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Sample records for relevant hohlraums apply

  1. Laser scattering in large-scale-length plasmas relevant to National Ignition Facility hohlraums

    International Nuclear Information System (INIS)

    MacGowan, B.J.; Berger, R.L.; Afeyan, B.B.

    1996-10-01

    We have used homogeneous plasmas of high density (up to 1.3 X 10 21 electrons per cm 3 ) and temperature (∼ 3 keV) with large density scale lengths (∼2 mm) to approximate conditions within National Ignition Facility (NIF) hohlraums. Within these plasmas we have studied the dependence of stimulated Raman (SRS) and Brillouin (SBS) scattering on beam smoothing and plasma conditions at the relevant laser intensity (3ω, 2 X 10 15 Wcm 2 ). Both SBS and SRS are reduced by the use of smoothing by spectral dispersion (SSD)

  2. Characteristics of ICF Relevant Hohlraums Driven by X-Rays from a Z-Pinch

    Energy Technology Data Exchange (ETDEWEB)

    BOWERS,R.L.; CHANDLER,GORDON A.; HEBRON,DAVID E.; LEEPER,RAMON J.; MATUSKA,W.; MOCK,RAYMOND CECIL; NASH,THOMAS J.; OLSON,RICHARD E.; PETERSON,D.L.; PETERSON,R.R.; RUGGLES,LAURENCE E.; RUIZ,CARLOS L.; SANFORD,THOMAS W. L.; SIMPSON,WALTER W.; VESEY,ROGER A.

    1999-11-03

    Radiation environments characteristic of those encountered during the low-temperature foot pulse and subsequent higher-temperature early-step pulses (without the foot pulse) required for indirect-drive ICF ignition on the National ignition Facility have been produced in hohlraums driven by x-rays from a z-pinch. These environments provide a platform to better understand the dynamics of full-scale NIF hohlraums, ablator material, and capsules prior to NIF completion. Radiation temperature, plasma fill, and wall motion of these hohlraums are discussed.

  3. Laser beam smoothing and backscatter saturation processes in plasmas relevant to national ignition facility hohlraums

    International Nuclear Information System (INIS)

    MacGowan, B.J.; Berger, R.L.; Cohen, B.I.

    2001-01-01

    We have used gas-filled targets irradiated by the Nova laser to simulate National Ignition Facility (NIF) hohlraum plasmas and to study the dependence of Stimulated Raman (SRS) and Brillouin (SBS) Scattering on beam smoothing at a range of laser intensities (3ω, 2-410 15 Wcm -2 ) and plasma conditions. We have demonstrated the effectiveness of polarization smoothing as a potential upgrade to the NIF. Experiments with higher intensities and higher densities characteristic of 350eV hohlraum designs indicate that with appropriate beam smoothing the backscatter from such hohlraums may be tolerable. (author)

  4. Characteristics of ICF Relevant Hohlraums Driven by X-Rays from a Z-Pinch

    International Nuclear Information System (INIS)

    BOWERS, R.L.; CHANDLER, GORDON A.; HEBRON, DAVID E.; LEEPER, RAMON J.; MATUSKA, W.; MOCK, RAYMOND CECIL; NASH, THOMAS J.; OLSON, RICHARD E.; PETERSON, D.L.; PETERSON, R.R.; RUGGLES, LAURENCE E.; RUIZ, CARLOS L.; SANFORD, THOMAS W. L.; SIMPSON, WALTER W.; VESEY, ROGER A.

    1999-01-01

    Radiation environments characteristic of those encountered during the low-temperature foot pulse and subsequent higher-temperature early-step pulses (without the foot pulse) required for indirect-drive ICF ignition on the National ignition Facility have been produced in hohlraums driven by x-rays from a z-pinch. These environments provide a platform to better understand the dynamics of full-scale NIF hohlraums, ablator material, and capsules prior to NIF completion. Radiation temperature, plasma fill, and wall motion of these hohlraums are discussed

  5. A unified free-form representation applied to the shape optimization of the hohlraum with octahedral 6 laser entrance holes

    International Nuclear Information System (INIS)

    Jiang, Shaoen; Ding, Yongkun; Huang, Yunbao; Li, Haiyan; Jing, Longfei; Huang, Tianxuan

    2016-01-01

    The hohlraum is very crucial for indirect laser driven Inertial Confinement Fusion. Usually, its shape is designed as sphere, cylinder, or rugby with some kind of fixed functions, such as ellipse or parabola. Recently, a spherical hohlraum with octahedral 6 laser entrance holes (LEHs) has been presented with high flux symmetry [Lan et al., Phys. Plasmas 21, 010704 (2014); 21, 052704 (2014)]. However, there is only one shape parameter, i.e., the hohlraum to capsule radius ratio, being optimized. In this paper, we build the hohlraum with octahedral 6LEHs with a unified free-form representation, in which, by varying additional shape parameters: (1) available hohlraum shapes can be uniformly and accurately represented, (2) it can be used to understand why the spherical hohlraum has higher flux symmetry, (3) it allows us to obtain a feasible shape design field satisfying flux symmetry constraints, and (4) a synthetically optimized hohlraum can be obtained with a tradeoff of flux symmetry and other hohlraum performance. Finally, the hohlraum with octahedral 6LEHs is modeled, analyzed, and then optimized based on the unified free-form representation. The results show that a feasible shape design field with flux asymmetry no more than 1% can be obtained, and over the feasible design field, the spherical hohlraum is validated to have the highest flux symmetry, and a synthetically optimal hohlraum can be found with closing flux symmetry but larger volume between laser spots and centrally located capsule

  6. A unified free-form representation applied to the shape optimization of the hohlraum with octahedral 6 laser entrance holes

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Shaoen; Ding, Yongkun [Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Huang, Yunbao, E-mail: Huangyblhy@gmail.com, E-mail: scmyking-2008@163.com; Li, Haiyan [Key Laboratory of Computer Integrated Manufacturing System, Guangdong University of Technology, Guangzhou 510006 (China); Jing, Longfei, E-mail: Huangyblhy@gmail.com, E-mail: scmyking-2008@163.com; Huang, Tianxuan [Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900 (China)

    2016-01-15

    The hohlraum is very crucial for indirect laser driven Inertial Confinement Fusion. Usually, its shape is designed as sphere, cylinder, or rugby with some kind of fixed functions, such as ellipse or parabola. Recently, a spherical hohlraum with octahedral 6 laser entrance holes (LEHs) has been presented with high flux symmetry [Lan et al., Phys. Plasmas 21, 010704 (2014); 21, 052704 (2014)]. However, there is only one shape parameter, i.e., the hohlraum to capsule radius ratio, being optimized. In this paper, we build the hohlraum with octahedral 6LEHs with a unified free-form representation, in which, by varying additional shape parameters: (1) available hohlraum shapes can be uniformly and accurately represented, (2) it can be used to understand why the spherical hohlraum has higher flux symmetry, (3) it allows us to obtain a feasible shape design field satisfying flux symmetry constraints, and (4) a synthetically optimized hohlraum can be obtained with a tradeoff of flux symmetry and other hohlraum performance. Finally, the hohlraum with octahedral 6LEHs is modeled, analyzed, and then optimized based on the unified free-form representation. The results show that a feasible shape design field with flux asymmetry no more than 1% can be obtained, and over the feasible design field, the spherical hohlraum is validated to have the highest flux symmetry, and a synthetically optimal hohlraum can be found with closing flux symmetry but larger volume between laser spots and centrally located capsule.

  7. Dynamics of a Z Pinch X Ray Source for Heating ICF Relevant Hohlraums to 120-160eV

    Energy Technology Data Exchange (ETDEWEB)

    SANFORD,THOMAS W. L.; OLSON,RICHARD E.; MOCK,RAYMOND CECIL; CHANDLER,GORDON A.; LEEPER,RAMON J.; NASH,THOMAS J.; RUGGLES,LAURENCE E.; SIMPSON,WALTER W.; STRUVE,KENNETH W.; PETERSON,D.L.; BOWERS,R.L.; MATUSKA,W.

    2000-07-10

    A z-pinch radiation source has been developed that generates 60 {+-} 20 KJ of x-rays with a peak power of 13 {+-} 4 TW through a 4-mm diameter axial aperture on the Z facility. The source has heated NIF (National Ignition Facility)-scale (6-mm diameter by 7-mm high) hohlraums to 122 {+-} 6 eV and reduced-scale (4-mm diameter by 4-mm high) hohlraums to 155 {+-} 8 eV -- providing environments suitable for indirect-drive ICF (Inertial Confinement Fusion) studies. Eulerian-RMHC (radiation-hydrodynamics code) simulations that take into account the development of the Rayleigh-Taylor instability in the r-z plane provide integrated calculations of the implosion, x-ray generation, and hohlraum heating, as well as estimates of wall motion and plasma fill within the hohlraums. Lagrangian-RMHC simulations suggest that the addition of a 6 mg/cm{sup 3} CH{sub 2} fill in the reduced-scale hohlraum decreases hohlraum inner-wall velocity by {approximately}40% with only a 3--5% decrease in peak temperature, in agreement with measurements.

  8. Dynamics of a Z Pinch X Ray Source for Heating ICF Relevant Hohlraums to 120-160eV

    International Nuclear Information System (INIS)

    Sanford, Thomas W.L.; Olson, Richard E.; Mock, Raymond Cecil; Chandler, Gordon A.; Leeper, Ramon J.; Nash, Thomas J.; Ruggles, Laurence E.; Simpson, Walter W.; Struve, Kenneth W.; Peterson, D.L.; Bowers, R.L.; Matuska, W.

    2000-01-01

    A z-pinch radiation source has been developed that generates 60 ± 20 KJ of x-rays with a peak power of 13 ± 4 TW through a 4-mm diameter axial aperture on the Z facility. The source has heated NIF (National Ignition Facility)-scale (6-mm diameter by 7-mm high) hohlraums to 122 ± 6 eV and reduced-scale (4-mm diameter by 4-mm high) hohlraums to 155 ± 8 eV -- providing environments suitable for indirect-drive ICF (Inertial Confinement Fusion) studies. Eulerian-RMHC (radiation-hydrodynamics code) simulations that take into account the development of the Rayleigh-Taylor instability in the r-z plane provide integrated calculations of the implosion, x-ray generation, and hohlraum heating, as well as estimates of wall motion and plasma fill within the hohlraums. Lagrangian-RMHC simulations suggest that the addition of a 6 mg/cm 3 CH 2 fill in the reduced-scale hohlraum decreases hohlraum inner-wall velocity by ∼40% with only a 3--5% decrease in peak temperature, in agreement with measurements

  9. Dynamics of a Z-pinch x-ray source for heating inertial-confinement-fusion relevant hohlraums to 120--160 eV

    Energy Technology Data Exchange (ETDEWEB)

    Sanford, T. W. L.; Olson, R. E.; Mock, R. C.; Chandler, G. A.; Leeper, R. J.; Nash, T. J.; Ruggles, L. E.; Simpson, W. W.; Struve, K. W.; Peterson, D. L. (and others)

    2000-11-01

    A Z-pinch radiation source has been developed that generates 60{+-}20 kJ of x rays with a peak power of 13{+-}4 TW through a 4-mm-diam axial aperture on the Z facility. The source has heated National Ignition Facility-scale (6-mm-diam by 7-mm-high) hohlraums to 122{+-}6 eV and reduced-scale (4-mm-diam by 4-mm-high) hohlraums to 155{+-}8 eV -- providing environments suitable for indirect-drive inertial confinement fusion studies. Eulerian-RMHC (radiation-magnetohydrodynamics code) simulations that take into account the development of the Rayleigh--Taylor instability in the r--z plane provide integrated calculations of the implosion, x-ray generation, and hohlraum heating, as well as estimates of wall motion and plasma fill within the hohlraums. Lagrangian-RMHC simulations suggest that the addition of a 6 mg/cm3 CH{sub 2} fill in the reduced-scale hohlraum decreases hohlraum inner-wall velocity by {approx}40% with only a 3%--5% decrease in peak temperature, in agreement with measurements.

  10. Dynamics of a Z-pinch x-ray source for heating inertial-confinement-fusion relevant hohlraums to 120--160 eV

    International Nuclear Information System (INIS)

    Sanford, T. W. L.; Olson, R. E.; Mock, R. C.; Chandler, G. A.; Leeper, R. J.; Nash, T. J.; Ruggles, L. E.; Simpson, W. W.; Struve, K. W.; Peterson, D. L.

    2000-01-01

    A Z-pinch radiation source has been developed that generates 60±20 kJ of x rays with a peak power of 13±4 TW through a 4-mm-diam axial aperture on the Z facility. The source has heated National Ignition Facility-scale (6-mm-diam by 7-mm-high) hohlraums to 122±6 eV and reduced-scale (4-mm-diam by 4-mm-high) hohlraums to 155±8 eV -- providing environments suitable for indirect-drive inertial confinement fusion studies. Eulerian-RMHC (radiation-magnetohydrodynamics code) simulations that take into account the development of the Rayleigh--Taylor instability in the r--z plane provide integrated calculations of the implosion, x-ray generation, and hohlraum heating, as well as estimates of wall motion and plasma fill within the hohlraums. Lagrangian-RMHC simulations suggest that the addition of a 6 mg/cm3 CH 2 fill in the reduced-scale hohlraum decreases hohlraum inner-wall velocity by ∼40% with only a 3%--5% decrease in peak temperature, in agreement with measurements

  11. Dynamics of a Z-pinch x-ray source for heating inertial-confinement-fusion relevant hohlraums to 120-160 eV

    Science.gov (United States)

    Sanford, T. W. L.; Olson, R. E.; Mock, R. C.; Chandler, G. A.; Leeper, R. J.; Nash, T. J.; Ruggles, L. E.; Simpson, W. W.; Struve, K. W.; Peterson, D. L.; Bowers, R. L.; Matuska, W.

    2000-11-01

    A Z-pinch radiation source has been developed that generates 60±20 kJ of x rays with a peak power of 13±4 TW through a 4-mm-diam axial aperture on the Z facility. The source has heated National Ignition Facility-scale (6-mm-diam by 7-mm-high) hohlraums to 122±6 eV and reduced-scale (4-mm-diam by 4-mm-high) hohlraums to 155±8 eV—providing environments suitable for indirect-drive inertial confinement fusion studies. Eulerian-RMHC (radiation-magnetohydrodynamics code) simulations that take into account the development of the Rayleigh-Taylor instability in the r-z plane provide integrated calculations of the implosion, x-ray generation, and hohlraum heating, as well as estimates of wall motion and plasma fill within the hohlraums. Lagrangian-RMHC simulations suggest that the addition of a 6 mg/cm3 CH2 fill in the reduced-scale hohlraum decreases hohlraum inner-wall velocity by ˜40% with only a 3%-5% decrease in peak temperature, in agreement with measurements.

  12. Novel spherical hohlraum with cylindrical laser entrance holes and shields

    Energy Technology Data Exchange (ETDEWEB)

    Lan, Ke [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Zheng, Wudi [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)

    2014-09-15

    Our recent works [K. Lan et al., Phys. Plasmas 21, 010704 (2014); K. Lan et al., Phys. Plasmas 21, 052704 (2014)] have shown that the octahedral spherical hohlraums are superior to the cylindrical hohlraums in both higher symmetry during the capsule implosion and lower backscatter without supplementary technology. However, both the coupling efficiency from the drive laser energy to the capsule and the capsule symmetry decrease remarkably when larger laser entrance holes (LEHs) are used. In addition, the laser beams injected at angles > 45° transport close to the hohlraum wall, thus the wall blowoff causes the LEH to close faster and results in strong laser plasma interactions inside the spherical hohlraums. In this letter, we propose a novel octahedral hohlraum with LEH shields and cylindrical LEHs to alleviate these problems. From our theoretical study, with the LEH shields, the laser coupling efficiency is significantly increased and the capsule symmetry is remarkably improved in the spherical hohlraums. The cylindrical LEHs take advantage of the cylindrical hohlraum near the LEH and mitigate the influence of the blowoff on laser transport inside a spherical hohlraum. The cylindrical LEHs can also be applied to the rugby and elliptical hohlraums.

  13. Novel spherical hohlraum with cylindrical laser entrance holes and shields

    International Nuclear Information System (INIS)

    Lan, Ke; Zheng, Wudi

    2014-01-01

    Our recent works [K. Lan et al., Phys. Plasmas 21, 010704 (2014); K. Lan et al., Phys. Plasmas 21, 052704 (2014)] have shown that the octahedral spherical hohlraums are superior to the cylindrical hohlraums in both higher symmetry during the capsule implosion and lower backscatter without supplementary technology. However, both the coupling efficiency from the drive laser energy to the capsule and the capsule symmetry decrease remarkably when larger laser entrance holes (LEHs) are used. In addition, the laser beams injected at angles > 45° transport close to the hohlraum wall, thus the wall blowoff causes the LEH to close faster and results in strong laser plasma interactions inside the spherical hohlraums. In this letter, we propose a novel octahedral hohlraum with LEH shields and cylindrical LEHs to alleviate these problems. From our theoretical study, with the LEH shields, the laser coupling efficiency is significantly increased and the capsule symmetry is remarkably improved in the spherical hohlraums. The cylindrical LEHs take advantage of the cylindrical hohlraum near the LEH and mitigate the influence of the blowoff on laser transport inside a spherical hohlraum. The cylindrical LEHs can also be applied to the rugby and elliptical hohlraums

  14. Tetrahedral hohlraums at omega

    International Nuclear Information System (INIS)

    Kyrala, G.A.; Goldman, S.R.; Batha, S.H.; Wallace, J.M.; Klare, K.A.; Schappert, G.T.; Oertel, J.; Turner, R.E.

    2000-01-01

    We have initiated a study of the usefulness of tetrahedrally illuminated spherical hohlraums, using the Omega laser beams, to drive planar shocks in packages that require indirect drive. A first suite of experiments used spherical hohlraums with a 2-μm thick gold wall surrounded by a 100-μm thick epoxy layer and had an internal diameter of 2.8 mm. Four laser entrance holes each of diameter 700 μm, located on the tips of a regular tetrahedron were used. The shock velocities and the shock uniformities were measured using optical shock break out techniques. The hohlraum x-ray radiation spectrum was also measured using a 10-channel x-ray detector. Tentatively, peak temperatures approaching 195 eV were achieved and shock speeds of 60 μm/ns were measured, when the hohlraum was driven by 22 kJ of 3 ω radiation. (authors)

  15. Gas-filled hohlraum experiments at the National Ignition Facility

    International Nuclear Information System (INIS)

    Fernandez, Juan C.; Goldman, S.R.; Kline, J.L.; Dodd, E.S.; Gautier, C.; Grim, G.P.; Hegelich, B.M.; Montgomery, D.S.; Lanier, N.E.; Rose, H.; Schmidt, D.W.; Workman, J.B.; Braun, D.G.; Dewald, E.L.; Landen, O.L.; Campbell, K.M.; Holder, J.P.; MacKinnon, A.J.; Niemann, C.; Schein, J.

    2006-01-01

    Experiments done at the National Ignition Facility laser [J. A. Paisner, E. M. Campbell, and W. Hogan, Fusion Technol. 26, 755 (1994)] using gas-filled hohlraums demonstrate a key ignition design feature, i.e., using plasma pressure from a gas fill to tamp the hohlraum-wall expansion for the duration of the laser pulse. Moreover, our understanding of hohlraum energetics and the ability to predict the hohlraum soft-x-ray drive has been validated in ignition-relevant conditions. Finally, the laser reflectivity from stimulated Raman scattering in the fill plasma, a key threat to hohlraum performance, is shown to be suppressed by choosing a design with a sufficiently high ratio of electron temperature to density

  16. Scaling laws for specialized hohlraums

    International Nuclear Information System (INIS)

    Rosen, M.D.

    1993-01-01

    The author presents scaling laws for the behavior of hohlraums that are somewhat more complex than a simple sphere or cylinder. In particular the author considers hohlraums that are in what has become known as a open-quotes primaryclose quotes open-quotes secondaryclose quotes configuration, namely geometries in which the laser is absorbed in a primary region of a hohlraum, and only radiation energy is transported to a secondary part of the hohlraum that is shielded from seeing the laser light directly. Such hohlraums have been in use of late for doing LTE opacity experiments on a sample in the secondary and in recently proposed open-quotes shimmedclose quotes hohlraums that use gold disks on axis to block a capsule's view of the cold laser entrance hole. The temperature/drive of the secondary, derived herein, scales somewhat differently than the drive in simple hohlraums

  17. Kinetic modeling of Nernst effect in magnetized hohlraums.

    Science.gov (United States)

    Joglekar, A S; Ridgers, C P; Kingham, R J; Thomas, A G R

    2016-04-01

    We present nanosecond time-scale Vlasov-Fokker-Planck-Maxwell modeling of magnetized plasma transport and dynamics in a hohlraum with an applied external magnetic field, under conditions similar to recent experiments. Self-consistent modeling of the kinetic electron momentum equation allows for a complete treatment of the heat flow equation and Ohm's law, including Nernst advection of magnetic fields. In addition to showing the prevalence of nonlocal behavior, we demonstrate that effects such as anomalous heat flow are induced by inverse bremsstrahlung heating. We show magnetic field amplification up to a factor of 3 from Nernst compression into the hohlraum wall. The magnetic field is also expelled towards the hohlraum axis due to Nernst advection faster than frozen-in flux would suggest. Nonlocality contributes to the heat flow towards the hohlraum axis and results in an augmented Nernst advection mechanism that is included self-consistently through kinetic modeling.

  18. Progress in octahedral spherical hohlraum study

    Directory of Open Access Journals (Sweden)

    Ke Lan

    2016-01-01

    Full Text Available In this paper, we give a review of our theoretical and experimental progress in octahedral spherical hohlraum study. From our theoretical study, the octahedral spherical hohlraums with 6 Laser Entrance Holes (LEHs of octahedral symmetry have robust high symmetry during the capsule implosion at hohlraum-to-capsule radius ratio larger than 3.7. In addition, the octahedral spherical hohlraums also have potential superiority on low backscattering without supplementary technology. We studied the laser arrangement and constraints of the octahedral spherical hohlraums, and gave a design on the laser arrangement for ignition octahedral hohlraums. As a result, the injection angle of laser beams of 50°–60° was proposed as the optimum candidate range for the octahedral spherical hohlraums. We proposed a novel octahedral spherical hohlraum with cylindrical LEHs and LEH shields, in order to increase the laser coupling efficiency and improve the capsule symmetry and to mitigate the influence of the wall blowoff on laser transport. We studied on the sensitivity of the octahedral spherical hohlraums to random errors and compared the sensitivity among the octahedral spherical hohlraums, the rugby hohlraums and the cylindrical hohlraums, and the results show that the octahedral spherical hohlraums are robust to these random errors while the cylindrical hohlraums are the most sensitive. Up till to now, we have carried out three experiments on the spherical hohlraum with 2 LEHs on Shenguang(SG laser facilities, including demonstration of improving laser transport by using the cylindrical LEHs in the spherical hohlraums, spherical hohlraum energetics on the SGIII prototype laser facility, and comparisons of laser plasma instabilities between the spherical hohlraums and the cylindrical hohlraums on the SGIII laser facility.

  19. Laser plasma interactions in hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Kruer, W.L.

    1994-10-05

    Lasers plasma instabilities are an important constraint in x-ray driven inertial confinement fusion. In hohlraums irradiated with 1.06 {mu}m light on the Shiva laser, plasma instabilities were extremely deleterious, driving the program to the use of shorter wavelength light. Excellent coupling has been achieved in hohlraums driven with 0.35 {mu}m light on the Nova laser. Considerable attention is being given to the scaling of this excellent coupling to the larger hohlraums for an ignition target. Various instability control mechanisms such as large plasma wave damping and laser beam incoherence are discussed, as well as scaling experiments to check the instability levels.

  20. Development and characterization of a Z-pinch-driven hohlraum high-yield inertial confinement fusion target concept

    International Nuclear Information System (INIS)

    Cuneo, Michael E.; Vesey, Roger A.; Porter, John L. Jr.; Chandler, Gordon A.; Fehl, David L.; Gilliland, Terrance L.; Hanson, David L.; McGurn, John S.; Reynolds, Paul G.; Ruggles, Laurence E.; Seamen, Hans; Spielman, Rick B.; Struve, Ken W.; Stygar, William A.; Simpson, Walter W.; Torres, Jose A.; Wenger, David F.; Hammer, James H.; Rambo, Peter W.; Peterson, Darrell L.

    2001-01-01

    Initial experiments to study the Z-pinch-driven hohlraum high-yield inertial confinement fusion (ICF) concept of Hammer, Tabak, and Porter [Hammer et al., Phys. Plasmas 6, 2129 (1999)] are described. The relationship between measured pinch power, hohlraum temperature, and secondary hohlraum coupling ('hohlraum energetics') is well understood from zero-dimensional semianalytic, and two-dimensional view factor and radiation magnetohydrodynamics models. These experiments have shown the highest x-ray powers coupled to any Z-pinch-driven secondary hohlraum (26±5 TW), indicating the concept could scale to fusion yields of >200 MJ. A novel, single-sided power feed, double-pinch driven secondary that meets the pinch simultaneity requirements for polar radiation symmetry has also been developed. This source will permit investigation of the pinch power balance and hohlraum geometry requirements for ICF relevant secondary radiation symmetry, leading to a capsule implosion capability on the Z accelerator [Spielman et al., Phys. Plasmas 5, 2105 (1998)

  1. Hohlraum modeling for opacity experiments on the National Ignition Facility

    Science.gov (United States)

    Dodd, E. S.; DeVolder, B. G.; Martin, M. E.; Krasheninnikova, N. S.; Tregillis, I. L.; Perry, T. S.; Heeter, R. F.; Opachich, Y. P.; Moore, A. S.; Kline, J. L.; Johns, H. M.; Liedahl, D. A.; Cardenas, T.; Olson, R. E.; Wilde, B. H.; Urbatsch, T. J.

    2018-06-01

    This paper discusses the modeling of experiments that measure iron opacity in local thermodynamic equilibrium (LTE) using laser-driven hohlraums at the National Ignition Facility (NIF). A previous set of experiments fielded at Sandia's Z facility [Bailey et al., Nature 517, 56 (2015)] have shown up to factors of two discrepancies between the theory and experiment, casting doubt on the validity of the opacity models. The purpose of the new experiments is to make corroborating measurements at the same densities and temperatures, with the initial measurements made at a temperature of 160 eV and an electron density of 0.7 × 1022 cm-3. The X-ray hot spots of a laser-driven hohlraum are not in LTE, and the iron must be shielded from a direct line-of-sight to obtain the data [Perry et al., Phys. Rev. B 54, 5617 (1996)]. This shielding is provided either with the internal structure (e.g., baffles) or external wall shapes that divide the hohlraum into a laser-heated portion and an LTE portion. In contrast, most inertial confinement fusion hohlraums are simple cylinders lacking complex gold walls, and the design codes are not typically applied to targets like those for the opacity experiments. We will discuss the initial basis for the modeling using LASNEX, and the subsequent modeling of five different hohlraum geometries that have been fielded on the NIF to date. This includes a comparison of calculated and measured radiation temperatures.

  2. Gas-filled hohlraum fabrication

    International Nuclear Information System (INIS)

    Salazar, M.A.; Gobby, P.L.; Foreman, L.R.; Bush, H. Jr.; Gomez, V.M.; Moore, J.E.; Stone, G.F.

    1995-01-01

    Los Alamos National Laboratory (LANL) researchers have fabricated and fielded gas-filled hohlraums at the Lawrence Livermore National Laboratory (LLNL) Nova laser. Fill pressures of 1--5 atmospheres have been typical. We describe the production of the parts, their assembly and fielding. Emphasis is placed on the production of gas-tight polyimide windows and the fielding apparatus and procedure

  3. Exploring the limits of case-to-capsule ratio, pulse length, and picket energy for symmetric hohlraum drive on NIF

    Science.gov (United States)

    Callahan, Debra

    2017-10-01

    Over the past two years, we have been exploring low gasfill hohlraums (He fill at 0.3-0.6 mg/cc) as an alternate to the high gasfill hohlraums used in NIC and the High Foot campaigns (He fill at 1-1.6 mg/cc). These low fill hohlraums have significantly reduced laser-plasma instabilities and increased coupling to the target as compared to the high fill hohlraums and take us to a new region of parameter space where the hohlraum is limited by hydrodynamic motion of the hohlraum wall rather than by laser plasma interactions. The outer cone laser beams interacting with the hohlraum wall produce a ``bubble'' of low density, high Z material that moves toward the center of the hohlraum. This gold or depleted uranium bubble eventually intercepts the inner cone beams and prevents the inner cone beams from reaching the waist of the hohlraum-where they are needed to get a symmetric implosion. Thus, the speed of the bubble expansion sets the allowable pulse duration in a given size hohlraum. Data and simulations suggest that the bubble is launched by the early part of the laser pulse (``picket'') and the gold/gas interfaces moves nearly linearly in time toward the axis of the hohlraum. The velocity of the bubble is related to the square root of the energy in the picket of the pulse - thus the picket energy and pulse duration set the allowable hohlraum size and case-to-capsule ratio. In this talk, will discuss a data based model to describe the bubble motion and apply this model to a broad set of data from a variety of ablators (CH, HDC, Be), pulse durations (6-14 ns), case-to-capsule ratios (rhohl/rcap of 3-4.2), hohlraum sizes (5.4-6.7 mm diameter), and hohlraum gasfill densities (0.3-0.6 mg/cc). We will discuss how this model can help guide future designs and how improvements in the hohlraum (foam liners, hohlraum shape) can open up new parts of parameter space. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National

  4. The maxillae: integrated and applied anatomy relevant to dentistry.

    Science.gov (United States)

    Du Tolt, D F; Nortjé, Curly

    2003-09-01

    The union of the two paired maxillae form the whole upper jaw. Individual components of the maxilla contribute to the formation of the face, nose, mouth and orbit. The bony surfaces are in relation to the infratemporal and pterygopalatine fossae. Grooves, openings and foramina lend passage to structures such as the infra-orbital, posterior superior alveolar, nasopalatine and greater palatine nerves. These nerves are of great importance for regional anaesthesia in dentistry. The maxillary antrum of Highmore is frequently affected by pathological processes such as accidental tooth root impaction during an extraction procedure, sinusitis, cysts, fractures (LeFort) and tumours. Fast-growing maxillary sinus tumours often breach the thin walls of this cavity and encroach upon adjacent structures such as the orbit, nose, cheek, infratemporal fossa and mouth. 'Blow-out' fractures through the orbital component may result in nerve and muscle entrapment. Alveolar processes form an arcade for the two incisors, one canine, two premolars and three molars on each side. Knowledge of regional and applied anatomy, relevant to the maxillae, is essential when considering diagnostic imaging by X-rays, CT, and MRI.

  5. Hohlraum manufacture for inertial confinement fusion

    International Nuclear Information System (INIS)

    Foreman, L.R.; Gobby, P.; Bartos, J.

    1994-01-01

    Hohlraums are an integral part of indirect drive targets for Inertial Confinement Fusion (ICF) research. Hohlraums are made by an electroforming process that combines elements of micromachining and coating technology. The authors describe how these target element are made and extension of the method that allow fabrication of other, more complex target components

  6. Kinetic modeling of Nernst effect in magnetized hohlraums

    OpenAIRE

    Joglekar, A. S.; Ridgers, Christopher Paul; Kingham, R J; Thomas, A. G. R.

    2016-01-01

    We present nanosecond time-scale Vlasov-Fokker-Planck-Maxwell modeling of magnetized plasma transport and dynamics in a hohlraum with an applied external magnetic field, under conditions similar to recent experiments. Self-consistent modeling of the kinetic electron momentum equation allows for a complete treatment of the heat flow equation and Ohm's law, including Nernst advection of magnetic fields. In addition to showing the prevalence of nonlocal behavior, we demonstrate that effects such...

  7. Wall-shaped hohlraum influence on symmetry and energetics in gas-filled hohlraums

    Science.gov (United States)

    Tassin, Veronique; Philippe, Franck; Laffite, Stephane; Videau, Laurent; Monteil, Marie-Christine; Villette, Bruno; Stemmler, Philippe; Bednarczyk, Sophie; Peche, Emilie; Reneaume, Benoit; Thessieux, Christian

    2008-11-01

    On the way to the LMJ completion, achieving ignition with 40 quads in a 2-cone configuration will be attempted as a first step. Theoretical investigation of a rugby-shaped hohlraum shows energetics optimization and a better symmetry control compared to a cylindrical hohlraum [1]. We recently conducted experiments on the Omega laser facility with 3 different wall-shaped methane-filled hohlraum configurations. We present here the experimental results. Energetics benefits are shown for reduced wall area hohlraums. The wall-shaped hohlraum influence on time-dependent radiation symmetry is also discussed. For the 3 gas-filled hohlraums configurations, we compare the foamball early-time radiographs, the D2Ar-filled capsule time-integrated images and the core self-emission images. [1] M. Vandenboomgaerde, Phys. Rev. Lett., 99, 065004 (2007).

  8. Comparison of high-density carbon implosions in unlined uranium versus gold hohlraums

    Science.gov (United States)

    Dewald, Eduard; Meezan, Nathan; Tommasini, Riccardo; Khan, Shahab; MacKinnon, Andrew; Berzak Hopkins, Laura; Divol, Laurent; Lepape, Sebastien; Moore, Alastair; Schneider, Marilyn; Pak, Arthur; Nikroo, Abbas; Landen, Otto

    2016-10-01

    In Inertial Confinement Fusion (ICF) implosions, laser energy is converted to x-ray radiation in hohlraums with High-Z walls. At radiation temperatures near 300 eV relevant for ICF experiments, the radiative losses in heating the wall are lower for U than for Au hohlraums. Furthermore, the intensity of the ``M-band'' x-rays with photon energies h ν >1.8 keV is lower for uranium, allowing for reduced capsule dopant concentrations employed to minimize inner ablator preheat and hence keep favorable fuel/ablator interface Atwood numbers. This in turn improves the ablator rocket efficiency and reduces the risk of polluting the hot-spot with emissive dopant material. The first uranium vacuum hohlraum experiments on the National Ignition Facility (NIF) with undoped high-density carbon (HDC, or diamond) capsules have demonstrated 30% lower ``M-band'' intensity relative to Au, resulting in lower inflight ablator thickness due to reduced preheat. In addition, fusion neutron yields are 2x higher in U than in Au hohlraums for D2-gas filled capsule implosions at ICF relevant velocities of 380 +/-20 km/s. These results have led the NIF ICF implosions to routinely employ U hohlraums. Prepared by LLNL under Contract DE-AC52-07NA27344.

  9. Progress of Rugby Hohlraum Experiments on Omega

    Science.gov (United States)

    Philippe, Franck; Tassin, Veronique; Casner, Alexis; Gauthier, Pascal; Seytor, Patricia; Monteil, Marie-Christine; Park, Hye-Sook; Robey, Harry; Ross, Steven; Amendt, Peter; Girard, Frederic; Villette, Bruno; Reverdin, Charles; Loiseau, Pascal; Caillaud, Tony; Landoas, Olivier; Li, Chi Kang; Petrasso, Richard; Seguin, Fredrick; Rosenberg, Markus

    2011-10-01

    The rugby hohlraum concept is predicted to enable better coupling and higher gains in the indirect drive approach to ignition. A collaborative experimental program is currently pursued on OMEGA to test this concept in preparation for future megajoule-scale ignition designs. A direct comparison of gas-filled rugby hohlraums with classical cylinders was recently performed, showing a significant (up to ~40%) observed x-ray drive enhancement and neutron yields that are consistently higher in the rugby case. This work extends and confirms our previous findings in empty rugby hohlraums.

  10. Radiation drive in laser heated hohlraums

    International Nuclear Information System (INIS)

    Suter, L.J.; Kauffman, R.L.; Darrow, C.B.

    1995-01-01

    Nearly 10 years of Nova experiments and analysis have lead to a relatively detailed quantitative and qualitative understanding of radiation drive in laser heated hohlraums. Our most successful quantitative modelling tool is 2D Lasnex numerical simulations. Analysis of the simulations provides us with insight into the details of the hohlraum drive. In particular we find hohlraum radiation conversion efficiency becomes quite high with longer pulses as the accumulated, high Z blow-off plasma begins to radiate. Extensive Nova experiments corroborate our quantitative and qualitative understanding

  11. Enthalpy generation from mixing in hohlraum-driven targets

    Science.gov (United States)

    Amendt, Peter; Milovich, Jose

    2016-10-01

    The increase in enthalpy from the physical mixing of two initially separated materials is analytically estimated and applied to ICF implosions and gas-filled hohlraums. Pressure and temperature gradients across a classical interface are shown to be the origin of enthalpy generation from mixing. The amount of enthalpy generation is estimated to be on the order of 100 Joules for a 10 micron-scale annular mixing layer between the solid deuterium-tritium fuel and the undoped high-density carbon ablator of a NIF-scale implosion. A potential resonance is found between the mixing layer thickness and gravitational (Cs2/ g) and temperature-gradient scale lengths, leading to elevated enthalpy generation. These results suggest that if mixing occurs in current capsule designs for the National Ignition Facility, the ignition margin may be appreciably eroded by the associated enthalpy of mixing. The degree of enthalpy generation from mixing of high- Z hohlraum wall material and low- Z gas fills is estimated to be on the order of 100 kJ or more for recent NIF-scale hohlraum experiments, which is consistent with the inferred missing energy based on observed delays in capsule implosion times. Work performed under the auspices of Lawrence Livermore National Security, LLC (LLNS) under Contract No. DE-AC52-07NA27344.

  12. Pulsed power driven hohlraum research at Sandia National Laboratories

    International Nuclear Information System (INIS)

    Leeper, R.J.; Alberts, T.E.; Allshouse, G.A.

    1996-01-01

    Three pulsed power driven hohlraum concepts are being investigated at Sandia for application to inertial fusion research. These hohlraums are driven by intense proton and Li ion beams as well as by two different types of z-pinch x-ray sources. Research on these hohlraum systems will continue on Sandia's PBFA II-Z facility

  13. Analysis of hohlraum energetics of the SG series and the NIF experiments with energy balance model

    Directory of Open Access Journals (Sweden)

    Guoli Ren

    2017-01-01

    Full Text Available The basic energy balance model is applied to analyze the hohlraum energetics data from the Shenguang (SG series laser facilities and the National Ignition Facility (NIF experiments published in the past few years. The analysis shows that the overall hohlraum energetics data are in agreement with the energy balance model within 20% deviation. The 20% deviation might be caused by the diversity in hohlraum parameters, such as material, laser pulse, gas filling density, etc. In addition, the NIF's ignition target designs and our ignition target designs given by simulations are also in accordance with the energy balance model. This work confirms the value of the energy balance model for ignition target design and experimental data assessment, and demonstrates that the NIF energy is enough to achieve ignition if a 1D spherical radiation drive could be created, meanwhile both the laser plasma instabilities and hydrodynamic instabilities could be suppressed.

  14. Suppression of Stimulated Brillouin Scattering in multiple-ion species inertial confinement fusion Hohlraum Plasmas

    International Nuclear Information System (INIS)

    Neumayer, P

    2007-01-01

    A long-standing problem in the field of laser-plasma interactions is to successfully employ multiple-ion species plasmas to reduce stimulated Brillouin scattering (SBS) in inertial confinement fusion (ICF) hohlraum conditions. Multiple-ion species increase significantly the linear Landau damping for acoustic waves. Consequently, recent hohlraum designs for indirect-drive ignition on the National Ignition Facility investigate wall liner material options so that the liner gain for parametric instabilities will be below threshold for the onset SBS. Although the effect of two-ion species plasmas on Landau damping has been directly observed with Thomson scattering, early experiments on SBS in these plasmas have suffered from competing non-linear effects or laser beam filamentation. In this study, a reduction of SBS scattering to below the percent level has been observed in hohlraums at Omega that emulate the plasma conditions in an indirect drive ICF experiments. These experiments have measured the laser-plasma interaction processes in ignition-relevant high-electron temperature regime demonstrating Landau damping as a controlling process for SBS. The hohlraums have been filled with various fractions of CO 2 and C 3 H 8 varying the ratio of the light (H) to heavy (C and O) ion density from 0 to 2.6. They have been heated by 14.5 kJ of 351-nm light, thus increasing progressively Landau damping by an order of magnitude at constant electron density and temperature. A delayed 351-nm interaction beam, spatially smoothed to produce a 200-(micro)m laser spot at best focus, has propagated along the axis of the hohlraum. The backscattered light, both into the lens and outside, the transmitted light through the hohlraum plasma and the radiation temperature of the hohlraum has been measured. For ignition relevant laser intensities (3-9 10 14 Wcm -2 ), we find that the SBS reflectivity scales as predicted with Landau damping from >30% to <1%. Simultaneously, the hohlraum radiation

  15. Current scaling of axially radiated power in dynamic hohlraums and dynamic hohlraum load design for ZR

    International Nuclear Information System (INIS)

    Mock, Raymond Cecil; Nash, Thomas J.; Sanford, Thomas W. L.

    2007-01-01

    We present designs for dynamic hohlraum z-pinch loads on the 28 MA, 140 ns driver ZR. The scaling of axially radiated power with current in dynamic hohlraums is reviewed. With adequate stability on ZR this scaling indicates that 30 TW of axially radiated power should be possible. The performance of the dynamic hohlraum load on the 20 MA, 100 ns driver Z is extensively reviewed. The baseline z-pinch load on Z is a nested tungsten wire array imploding onto on-axis foam. Data from a variety of x-ray diagnostics fielded on Z are presented. These diagnostics include x-ray diodes, bolometers, fast x-ray imaging cameras, and crystal spectrometers. Analysis of these data indicates that the peak dynamic radiation temperature on Z is between 250 and 300 eV from a diameter less than 1 mm. Radiation from the dynamic hohlraum itself or from a radiatively driven pellet within the dynamic hohlraum has been used to probe a variety of matter associated with the dynamic hohlraum: the tungsten z-pinch itself, tungsten sliding across the end-on apertures, a titanium foil over the end aperture, and a silicon aerogel end cap. Data showing the existence of asymmetry in radiation emanating from the two ends of the dynamic hohlraum is presented, along with data showing load configurations that mitigate this asymmetry. 1D simulations of the dynamic hohlraum implosion are presented and compared to experimental data. The simulations provide insight into the dynamic hohlraum behavior but are not necessarily a reliable design tool because of the inherently 3D behavior of the imploding nested tungsten wire arrays

  16. Implosion spectroscopy in Rugby hohlraums on OMEGA

    Science.gov (United States)

    Philippe, Franck; Tassin, Veronique; Bitaud, Laurent; Seytor, Patricia; Reverdin, Charles

    2014-10-01

    The rugby hohlraum concept has been validated in previous experiments on the OMEGA laser facility. This new hohlraum type can now be used as a well-characterized experimental platform to study indirect drive implosion, at higher radiation temperatures than would be feasible at this scale with classical cylindrical hohlraums. Recent experiments have focused on the late stages of implosion and hotspot behavior. The capsules included both a thin buried Titanium tracer layer, 0-3 microns from the inner surface, Argon dopant in the deuterium gas fuel and Germanium doped CH shells, providing a variety of spectral signatures of the plasma conditions in different parts of the target. X-ray spectroscopy and imaging were used to study compression, Rayleigh-Taylor instabilities growth at the inner surface and mix between the shell and gas.

  17. Pulsed power driven hohlraum research at Sandia National Laboratories

    Energy Technology Data Exchange (ETDEWEB)

    Leeper, R J; Alberts, T E; Allshouse, G A [Sandia Labs., Albuquerque, NM (United States); and others

    1997-12-31

    Three pulsed power driven hohlraum concepts are being investigated at Sandia National Laboratories. These hohlraums are driven by intense proton and Li ion beams as well as by two different types of z-pinch x-ray sources. The paper is an overview of the experiments that have been conducted on these hohlraum systems and discusses several new and novel hohlraum characterization diagnostics that have been developed for this work. These diagnostics include an active shock breakout measurement of hohlraum temperature and a new transmission grating spectrograph for detailed thermal radiation spectral measurements. (author). 3 figs., 6 refs.

  18. Pulsed power driven hohlraum research at Sandia National Laboratories

    International Nuclear Information System (INIS)

    Leeper, R.J.; Alberts, T.E.; Allshouse, G.A.

    1996-01-01

    Three pulsed power driven hohlraum concepts are being investigated at Sandia National Laboratories. These hohlraums are driven by intense proton and Li ion beams as well as by two different types of z-pinch x-ray sources. The paper is an overview of the experiments that have been conducted on these hohlraum systems and discusses several new and novel hohlraum characterization diagnostics that have been developed for this work. These diagnostics include an active shock breakout measurement of hohlraum temperature and a new transmission grating spectrograph for detailed thermal radiation spectral measurements. (author). 3 figs., 6 refs

  19. LDRD Final Report: Advanced Hohlraum Concepts

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Ogden S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-11-08

    Indirect drive inertial confinement fusion (ICF) experiments to date have mostly used cylindrical, laser-heated, gas-filled hohlraums to produce the radiation drive needed to symmetrically implode DT-filled fusion capsules. These hohlraums have generally been unable to produce a symmetric radiation drive through the end of the desired drive pulse, and are plagued with complications due to laser-plasma interactions (LPI) that have made it difficult to predict their performance. In this project we developed several alternate hohlraum concepts. These new hohlraums utilize different hohlraum geometries, radiation shields, and foam materials in an attempt to improve performance relative to cylindrical hohlraums. Each alternate design was optimized using radiation hydrodynamic (RH) design codes to implode a reference DT capsule with a high-density carbon (HDC) ablator. The laser power and energy required to produce the desired time-dependent radiation drive, and the resulting time-dependent radiation symmetry for each new concept were compared to the results for a reference cylindrical hohlraum. Since several of the new designs needed extra laser entrance holes (LEHs), techniques to keep small LEHs open longer, including high-Z foam liners and low-Z wires at the LEH axis, were investigated numerically. Supporting experiments and target fabrication efforts were also done as part of this project. On the Janus laser facility plastic tubes open at one end (halfraums) and filled with SiO2 or Ta2O5 foam were heated with a single 2w laser. Laser propagation and backscatter were measured. Generally the measured propagation was slower than calculated, and the measured laser backscatter was less than calculated. A comparable, scaled up experiment was designed for the NIF facility and four targets were built. Since low density gold foam was identified as a desirable material for lining the LEH and the hohlraum wall, a technique was developed to

  20. Analytic Models of High-Temperature Hohlraums

    International Nuclear Information System (INIS)

    Stygar, W.A.; Olson, R.E.; Spielman, R.B.; Leeper, R.J.

    2000-01-01

    A unified set of high-temperature-hohlraum models has been developed. For a simple hohlraum, P s = (A s +(1minusα W )A W +A H )σT R 4 + (4Vσ/c)(dT R r /dt) where P S is the total power radiated by the source, A s is the source area, A W is the area of the cavity wall excluding the source and holes in the wall, A H is the area of the holes, σ is the Stefan-Boltzmann constant, T R is the radiation brightness temperature, V is the hohlraum volume, and c is the speed of light. The wall albedo α W triple b ond (T W /T R ) 4 where T W is the brightness temperature of area A W . The net power radiated by the source P N = P S -A S σT R 4 , which suggests that for laser-driven hohlraums the conversion efficiency η CE be defined as P N /P LASER . The characteristic time required to change T R 4 in response to a change in P N is 4V/C((lminusα W )A W +A H ). Using this model, T R , α W , and η CE can be expressed in terms of quantities directly measurable in a hohlraum experiment. For a steady-state hohlraum that encloses a convex capsule, P N = {(1minusα W )A W +A H +((1minusα C )(A S +A W α W )A C /A T = )}σT RC 4 where α C is the capsule albedo, A C is the capsule area, A T triple b ond (A S +A W +A H ), and T RC is the brightness temperature of the radiation that drives the capsule. According to this relation, the capsule-coupling efficiency of the baseline National-Ignition-Facility (NIF) hohlraum is 15% higher than predicted by previous analytic expressions. A model of a hohlraum that encloses a z pinch is also presented

  1. Laser absorption, power transfer, and radiation symmetry during the first shock of inertial confinement fusion gas-filled hohlraum experiments

    International Nuclear Information System (INIS)

    Pak, A.; Dewald, E. L.; Landen, O. L.; Milovich, J.; Strozzi, D. J.; Berzak Hopkins, L. F.; Bradley, D. K.; Divol, L.; Ho, D. D.; MacKinnon, A. J.; Meezan, N. B.; Michel, P.; Moody, J. D.; Moore, A. S.; Schneider, M. B.; Town, R. P. J.; Hsing, W. W.; Edwards, M. J.

    2015-01-01

    Temporally resolved measurements of the hohlraum radiation flux asymmetry incident onto a bismuth coated surrogate capsule have been made over the first two nanoseconds of ignition relevant laser pulses. Specifically, we study the P2 asymmetry of the incoming flux as a function of cone fraction, defined as the inner-to-total laser beam power ratio, for a variety of hohlraums with different scales and gas fills. This work was performed to understand the relevance of recent experiments, conducted in new reduced-scale neopentane gas filled hohlraums, to full scale helium filled ignition targets. Experimental measurements, matched by 3D view factor calculations, are used to infer differences in symmetry, relative beam absorption, and cross beam energy transfer (CBET), employing an analytic model. Despite differences in hohlraum dimensions and gas fill, as well as in laser beam pointing and power, we find that laser absorption, CBET, and the cone fraction, at which a symmetric flux is achieved, are similar to within 25% between experiments conducted in the reduced and full scale hohlraums. This work demonstrates a close surrogacy in the dynamics during the first shock between reduced-scale and full scale implosion experiments and is an important step in enabling the increased rate of study for physics associated with inertial confinement fusion

  2. Laser absorption, power transfer, and radiation symmetry during the first shock of inertial confinement fusion gas-filled hohlraum experiments

    Science.gov (United States)

    Pak, A.; Dewald, E. L.; Landen, O. L.; Milovich, J.; Strozzi, D. J.; Berzak Hopkins, L. F.; Bradley, D. K.; Divol, L.; Ho, D. D.; MacKinnon, A. J.; Meezan, N. B.; Michel, P.; Moody, J. D.; Moore, A. S.; Schneider, M. B.; Town, R. P. J.; Hsing, W. W.; Edwards, M. J.

    2015-12-01

    Temporally resolved measurements of the hohlraum radiation flux asymmetry incident onto a bismuth coated surrogate capsule have been made over the first two nanoseconds of ignition relevant laser pulses. Specifically, we study the P2 asymmetry of the incoming flux as a function of cone fraction, defined as the inner-to-total laser beam power ratio, for a variety of hohlraums with different scales and gas fills. This work was performed to understand the relevance of recent experiments, conducted in new reduced-scale neopentane gas filled hohlraums, to full scale helium filled ignition targets. Experimental measurements, matched by 3D view factor calculations, are used to infer differences in symmetry, relative beam absorption, and cross beam energy transfer (CBET), employing an analytic model. Despite differences in hohlraum dimensions and gas fill, as well as in laser beam pointing and power, we find that laser absorption, CBET, and the cone fraction, at which a symmetric flux is achieved, are similar to within 25% between experiments conducted in the reduced and full scale hohlraums. This work demonstrates a close surrogacy in the dynamics during the first shock between reduced-scale and full scale implosion experiments and is an important step in enabling the increased rate of study for physics associated with inertial confinement fusion.

  3. Laser absorption, power transfer, and radiation symmetry during the first shock of inertial confinement fusion gas-filled hohlraum experiments

    Energy Technology Data Exchange (ETDEWEB)

    Pak, A.; Dewald, E. L.; Landen, O. L.; Milovich, J.; Strozzi, D. J.; Berzak Hopkins, L. F.; Bradley, D. K.; Divol, L.; Ho, D. D.; MacKinnon, A. J.; Meezan, N. B.; Michel, P.; Moody, J. D.; Moore, A. S.; Schneider, M. B.; Town, R. P. J.; Hsing, W. W.; Edwards, M. J. [Lawrence Livermore National Laboratory, Livermore, California, 94550 (United States)

    2015-12-15

    Temporally resolved measurements of the hohlraum radiation flux asymmetry incident onto a bismuth coated surrogate capsule have been made over the first two nanoseconds of ignition relevant laser pulses. Specifically, we study the P2 asymmetry of the incoming flux as a function of cone fraction, defined as the inner-to-total laser beam power ratio, for a variety of hohlraums with different scales and gas fills. This work was performed to understand the relevance of recent experiments, conducted in new reduced-scale neopentane gas filled hohlraums, to full scale helium filled ignition targets. Experimental measurements, matched by 3D view factor calculations, are used to infer differences in symmetry, relative beam absorption, and cross beam energy transfer (CBET), employing an analytic model. Despite differences in hohlraum dimensions and gas fill, as well as in laser beam pointing and power, we find that laser absorption, CBET, and the cone fraction, at which a symmetric flux is achieved, are similar to within 25% between experiments conducted in the reduced and full scale hohlraums. This work demonstrates a close surrogacy in the dynamics during the first shock between reduced-scale and full scale implosion experiments and is an important step in enabling the increased rate of study for physics associated with inertial confinement fusion.

  4. The physics of radiation driven ICF hohlraums

    International Nuclear Information System (INIS)

    Rosen, M.D.

    1995-01-01

    On the Nova Laser at LLNL, we have recently demonstrated many of the key elements required for assuring that the next proposed laser, the National Ignition Facility (NIF) will drive an Inertial Confinement Fusion (ICF) target to ignition. The target uses the recently declassified indirect drive (sometimes referred to as open-quotes radiation driveclose quotes) approach which converts laser light to x-rays inside a gold cylinder, which then acts as an x-ray open-quotes ovenclose quotes (called a hohlraum) to drive the fusion capsule in its center. On Nova we've demonstrated good understanding of the temperatures reached in hohlraums and of the ways to control the uniformity with which the x-rays drive the spherical fusion capsules. In this lecture we briefly review the fundamentals of ICF, and describe the capsule implosion symmetry advantages of the hohlraum approach. We then concentrate on a quantitative understanding of the scaling of radiation drive with hohlraum size and wall material, and with laser pulse length and power. We demonstrate that coupling efficiency of x-ray drive to the capsule increases as we proceed from Nova to the NIF and eventually to a reactor, thus increasing the gain of the system

  5. Optimizing implosion yields using rugby-shaped hohlraums

    Science.gov (United States)

    Park, Hye-Sook; Robey, H.; Amendt, P.; Philippe, F.; Casner, A.; Caillaud, T.; Bourgade, J.-L.; Landoas, O.; Li, C. K.; Petrasso, R.; Seguin, F.; Rosenberg, M.; Glebov, V. Yu.

    2009-11-01

    We present the first experimental results on optimizing capsule implosion experiments by using rugby-shaped hohlraums [1] on the Omega laser, University of Rochester. This campaign compared D2-filled capsule performance between standard cylindrical Au hohlraums and rugby-shaped hohlraums for demonstrating the energetics advantages of the rugby geometry. Not only did the rugby-shaped hohlraums show nearly 20% more x-ray drive energy over the cylindrical hohlraums, but also the high-performance design of the capsules provided nearly 20 times more DD neutrons than in any previous Omega hohlraum campaigns, thereby enabling use of neutron temporal diagnostics. Comparison with simulations on neutron burn histories, x-ray core imaging, backscattered laser light and radiation temperature are presented. [1] P. Amendt et al., Phys. Plasmas 15, 012702 (2008)

  6. Status Update: Modeling Energy Balance in NIF Hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Jones, O. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-07-22

    We have developed a standardized methodology to model hohlraum drive in NIF experiments. We compare simulation results to experiments by 1) comparing hohlraum xray fluxes and 2) comparing capsule metrics, such as bang times. Long-pulse, high gas-fill hohlraums require a 20-28% reduction in simulated drive and inclusion of ~15% backscatter to match experiment through (1) and (2). Short-pulse, low fill or near-vacuum hohlraums require a 10% reduction in simulated drive to match experiment through (2); no reduction through (1). Ongoing work focuses on physical model modifications to improve these matches.

  7. First Laser-Plasma Interaction and Hohlraum Experiments on NIF

    International Nuclear Information System (INIS)

    Dewald, E L; Glenzer, S H; Landen, O L; Suter, L J; Jones, O S; Schein, J; Froula, D; Divol, L; Campbell, K; Schneider, M S; McDonald, J W; Niemann, C; Mackinnon, A J

    2005-01-01

    Recently the first hohlraum experiments have been performed at the National Ignition Facility (NIF) in support of indirect drive Inertial Confinement Fusion (ICF) designs. The effects of laser beam smoothing by spectral dispersion (SSD) and polarization smoothing (PS) on the beam propagation in long scale gas-filled pipes has been studied at plasma scales as found in indirect drive gas filled ignition hohlraum designs. The long scale gas-filled target experiments have shown propagation over 7 mm of dense plasma without filamentation and beam break up when using full laser smoothing. Vacuum hohlraums have been irradiated with laser powers up to 6 TW, 1-9 ns pulse lengths and energies up to 17 kJ to activate several diagnostics, to study the hohlraum radiation temperature scaling with the laser power and hohlraum size, and to make contact with hohlraum experiments performed at the NOVA and Omega laser facilities. Subsequently, novel long laser pulse hohlraum experiments have tested models of hohlraum plasma filling and long pulse hohlraum radiation production. The validity of the plasma filling assessment in analytical models and in LASNEX calculations has been proven for the first time. The comparison of these results with modeling will be discussed

  8. First hohlraum drive studies on the National Ignition Facility

    International Nuclear Information System (INIS)

    Dewald, E.L.; Landen, O.L.; Suter, L.J.; Schein, J.; Holder, J.; Campbell, K.; Glenzer, S.H.; McDonald, J.W.; Niemann, C.; Mackinnon, A.J.; Schneider, M.S.; Haynam, C.; Hinkel, D.; Hammel, B.A.

    2006-01-01

    The first hohlraum experiments on the National Ignition Facility (NIF) [G. H. Miller, E. I. Moses, and C. R. Wuest, Nucl. Fusion 44, 228 (2004)] using the first four laser beams have activated the indirect-drive experimental capabilities and tested radiation temperature limits imposed by hohlraum plasma filling. Vacuum hohlraums have been irradiated with laser powers up to 9 TW, 1 to 9 ns long square pulses and energies of up to 17 kJ to study the hohlraum radiation temperature scaling with the laser power and hohlraum size, and to make contact with hohlraum experiments performed previously at other laser facilities. Furthermore, for a variety of hohlraum sizes and pulse lengths, the measured x-ray flux shows signatures of plasma filling that coincide with hard x-ray emission from plasma streaming out of the hohlraum. These observations agree with hydrodynamic simulations and with analytical modeling that includes hydrodynamic and coronal radiative losses. The modeling predicts radiation temperature limits on full NIF (1.8 MJ) that are significantly greater than required for ignition hohlraums

  9. High Foot Implosion Experiments in Rugby Hohlraums

    Science.gov (United States)

    Ralph, Joseph; Leidinger, J.-P.; Callahan, D.; Kaiser, P.; Morice, O.; Marion, D.; Moody, J. D.; Ross, J. S.; Amendt, P.; Kritcher, A. L.; Milovich, J. L.; Strozzi, D.; Hinkel, D.; Michel, P.; Berzak Hopkins, L.; Pak, A.; Dewald, E. L.; Divol, L.; Khan, S.; Rygg, R.; Hurricane, O.; Lawrence Livermore National Lab Team; CEA/DAM Team

    2015-11-01

    The rugby hohlraum design is aimed at providing uniform x-ray drive on the capsule while minimizing the need for crossed beam energy transfer (CBET). As part of a series of experiments at the NIF using rugby hohlraums, design improvements in dual axis shock tuning experiments produced some of the most symmetric shocks measured on implosion experiments at the NIF. Additionally, tuning of the in-flight shell and hot spot shape have demonstrated that capsules can be tuned between oblate and prolate with measured velocities of nearly 340 km/s. However, these experimental measurements were accompanied by high levels of Stimulated Raman Scattering (SRS) that may result from the long inner beam path length, reamplification of the inner SRS by the outers, significant (CBET) or a combination of these. All rugby shots results were achieved with lower levels of hot electrons that can preheat the DT fuel layer for increased adiabat and reduced areal density. Detailed results from these experiments and those planned throughout the summer will be presented and compared with results obtained from cylindrical hohlraums. This work performed under the auspices of U.S. Department of Energy by Lawrence Livermore National Lab under Contract DE-AC52-07NA27344.

  10. Progress in hohlraum physics for the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Moody, J. D., E-mail: moody4@llnl.gov; Callahan, D. A.; Hinkel, D. E.; Amendt, P. A.; Baker, K. L.; Bradley, D.; Celliers, P. M.; Dewald, E. L.; Divol, L.; Döppner, T.; Eder, D. C.; Edwards, M. J.; Jones, O.; Haan, S. W.; Ho, D.; Hopkins, L. B.; Izumi, N.; Kalantar, D.; Kauffman, R. L.; Kilkenny, J. D. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); and others

    2014-05-15

    Advances in hohlraums for inertial confinement fusion at the National Ignition Facility (NIF) were made this past year in hohlraum efficiency, dynamic shape control, and hot electron and x-ray preheat control. Recent experiments are exploring hohlraum behavior over a large landscape of parameters by changing the hohlraum shape, gas-fill, and laser pulse. Radiation hydrodynamic modeling, which uses measured backscatter, shows that gas-filled hohlraums utilize between 60% and 75% of the laser power to match the measured bang-time, whereas near-vacuum hohlraums utilize 98%. Experiments seem to be pointing to deficiencies in the hohlraum (instead of capsule) modeling to explain most of the inefficiency in gas-filled targets. Experiments have begun quantifying the Cross Beam Energy Transfer (CBET) rate at several points in time for hohlraum experiments that utilize CBET for implosion symmetry. These measurements will allow better control of the dynamic implosion symmetry for these targets. New techniques are being developed to measure the hot electron energy and energy spectra generated at both early and late time. Rugby hohlraums offer a target which requires little to no CBET and may be less vulnerable to undesirable dynamic symmetry “swings.” A method for detecting the effect of the energetic electrons on the fuel offers a direct measure of the hot electron effects as well as a means to test energetic electron mitigation methods. At higher hohlraum radiation temperatures (including near vacuum hohlraums), the increased hard x-rays (1.8–4 keV) may pose an x-ray preheat problem. Future experiments will explore controlling these x-rays with advanced wall materials.

  11. THE RELEVANCE OF DUESENBERRY CONSUMPTION THEORY! AN APPLIED CASE TO LATIN AMERICA

    OpenAIRE

    Parada Corrales, Jairo; Bacca Mejia, William

    2009-01-01

    In this paper we examine the to-date relevance of Duesenberry's Consumption Theory through an applied case to four economies in Latin America: Mexico, Brazil, Argentina and Colombia. Using annual time series of these countries we show that some empirical evidence of Duesenberry's theory still holds and should not be discarded in modern macroeconomics as it has happened in regular macro text books in mainstream economics. Duesenberry's theory includes important institutional factors that canno...

  12. Electromagnetic radiations from laser interaction with gas-filled Hohlraum

    Science.gov (United States)

    Yang, Ming; Yang, Yongmei; Li, Tingshuai; Yi, Tao; Wang, Chuanke; Liu, Shenye; Jiang, Shaoen; Ding, Yongkun

    2018-01-01

    The emission of intensive electromagnetic pulse (EMP) due to laser-target interactions at the ShenGuang-III laser facility has been evaluated by probes. EMP signals measured using the small discone antennas demonstrated two variation trends including a bilateral oscillation wave and a unilateral oscillation wave. The new trend of unilateral oscillation could be attributed to the hohlraum structure and low-Z gas in the hohlraum. The EMP waveform showed multiple peaks when the gas-filled hohlraum was shot by the high-power laser. Comparing the EMP signals with the verification of stimulated Raman scattering energy and hard x-ray energy spectrum, we found that the intensity of EMP signals decreased with the increase of the hohlraum size. The current results are expected to offer preliminary information to study physical processes on laser injecting gas-filled hohlraums in the National Ignition Facility implementation.

  13. Clinically applied medical ethnography: relevance to cultural competence in patient care.

    Science.gov (United States)

    Engebretson, Joan

    2011-06-01

    Medical anthropology provides an excellent resource for nursing research that is relevant to clinical nursing. By expanding the understanding of ethnographic research beyond ethnicity, nurses can conduct research that explores patient's constructions and explanatory models of health and healing and how they make meaning out of chronic conditions and negotiate daily life. These findings can have applicability to culturally competent care at both the organizational or systems level, as well as in the patient/provider encounter. Individual patient care can be improved by applying ethnographic research findings to build provider expertise and then using a cultural negotiation process for individualized patient care. Copyright © 2011. Published by Elsevier Inc.

  14. Laser plasma interaction on rugby hohlraum on the Omega Laser Facility: Comparisons between cylinder, rugby, and elliptical hohlraums

    Science.gov (United States)

    Masson-Laborde, P. E.; Monteil, M. C.; Tassin, V.; Philippe, F.; Gauthier, P.; Casner, A.; Depierreux, S.; Neuville, C.; Villette, B.; Laffite, S.; Seytor, P.; Fremerye, P.; Seka, W.; Teychenné, D.; Debayle, A.; Marion, D.; Loiseau, P.; Casanova, M.

    2016-02-01

    Gas-filled rugby-shaped hohlraums have demonstrated high performances compared to a classical similar diameter cylinder hohlraum with a nearly 40% increase of x-ray drive, 10% higher measured peak drive temperature, and an increase in neutron production. Experimental comparisons have been done between rugby, cylinder, and elliptical hohlraums. The impact of these geometry differences on the laser plasma instabilities is examined. Using comparisons with hydrodynamic simulations carried out with the code FCI2 and postprocessed by Piranah, we have been able to reproduce the stimulated Raman and Brillouin scattering spectrum of the different beams. Using a methodology based on a statistical analysis for the gain calculations, we show that the behavior of the laser plasma instabilities in rugby hohlraums can be reproduced. The efficiency of laser smoothing techniques to mitigate these instabilities are discussed, and we show that while rugby hohlraums exhibit more laser plasma instabilities than cylinder hohlraum, the latter can be mitigated in the case of an elliptical hohlraum.

  15. A novel three-axis cylindrical hohlraum designed for inertial confinement fusion ignition

    Science.gov (United States)

    Kuang, Longyu; Li, Hang; Jing, Longfei; Lin, Zhiwei; Zhang, Lu; Li, Liling; Ding, Yongkun; Jiang, Shaoen; Liu, Jie; Zheng, Jian

    2016-10-01

    A novel ignition hohlraum for indirect-drive inertial confinement fusion is proposed, which is named three-axis cylindrical hohlraum (TACH). TACH is a kind of 6 laser entrance holes (LEHs) hohlraum, which is orthogonally jointed of three cylindrical hohlraums. Laser beams are injected through every entrance hole with the same incident angle of 55°. A view-factor simulation result shows that the time-varying drive asymmetry of TACH is less than 1.0% in the whole drive pulse period without any supplementary technology. Coupling efficiency of TACH is close to that of 6 LEHs spherical hohlraum with corresponding size. Its plasma-filling time is close to that of typical cylindrical ignition hohlraum. Its laser plasma interaction has as low backscattering as the outer cone of the cylindrical ignition hohlraum. Therefore, TACH combines most advantages of various hohlraums and has little predictable risk, providing an important competitive candidate for ignition hohlraum.

  16. Numerical simulations of inertial confinement fusion hohlraum with LARED-integration code

    International Nuclear Information System (INIS)

    Li Jinghong; Li Shuanggui; Zhai Chuanlei

    2011-01-01

    In the target design of the Inertial Confinement Fusion (ICF) program, it is common practice to apply radiation hydrodynamics code to study the key physical processes happened in ICF process, such as hohlraum physics, radiation drive symmetry, capsule implosion physics in the radiation-drive approach of ICF. Recently, many efforts have been done to develop our 2D integrated simulation capability of laser fusion with a variety of optional physical models and numerical methods. In order to effectively integrate the existing codes and to facilitate the development of new codes, we are developing an object-oriented structured-mesh parallel code-supporting infrastructure, called JASMIN. Based on two-dimensional three-temperature hohlraum physics code LARED-H and two-dimensional multi-group radiative transfer code LARED-R, we develop a new generation two-dimensional laser fusion code under the JASMIN infrastructure, which enable us to simulate the whole process of laser fusion from the laser beams' entrance into the hohlraum to the end of implosion. In this paper, we will give a brief description of our new-generation two-dimensional laser fusion code, named LARED-Integration, especially in its physical models, and present some simulation results of holhraum. (author)

  17. Hohlraum Target Alignment from X-ray Detector Images using Starburst Design Patterns

    International Nuclear Information System (INIS)

    Leach, R.R.; Conder, A.; Edwards, O.; Kroll, J.; Kozioziemski, B.; Mapoles, E.; McGuigan, D.; Wilhelmsen, K.

    2010-01-01

    National Ignition Facility (NIF) is a high-energy laser facility comprised of 192 laser beams focused with enough power and precision on a hydrogen-filled spherical, cryogenic target to initiate a fusion reaction. The target container, or hohlraum, must be accurately aligned to an x-ray imaging system to allow careful monitoring of the frozen fuel layer in the target. To achieve alignment, x-ray images are acquired through starburst-shaped windows cut into opposite sides of the hohlraum. When the hohlraum is in alignment, the starburst pattern pairs match nearly exactly and allow a clear view of the ice layer formation on the edge of the target capsule. During the alignment process, x-ray image analysis is applied to determine the direction and magnitude of adjustment required. X-ray detector and source are moved in concert during the alignment process. The automated pointing alignment system described here is both accurate and efficient. In this paper, we describe the control and associated image processing that enables automation of the starburst pointing alignment.

  18. Laser-plasma interactions and implosion symmetry in rugby hohlraums

    Science.gov (United States)

    Michel, Pierre; Berger, R. L.; Lasinski, B. F.; Ross, J. S.; Divol, L.; Williams, E. A.; Meeker, D.; Langdon, B. A.; Park, H.; Amendt, P.

    2011-10-01

    Cross-beam energy transfer is studied in the context of ``rugby''-hohlraum experiments at the Omega laser facility in FY11, in preparation for future NIF experiments. The transfer acts in opposite direction between rugby and cylinder hohlraums due to the different beam pointing geometries and flow patterns. Its interaction with backscatter is also different as both happen in similar regions inside rugby hohlraums. We will analyze the effects of non-linearities and temporal beam smoothing on energy transfer using the code pF3d. Calculations will be compared to experiments at Omega; analysis of future rugby hohlraum experiments on NIF will also be presented. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  19. Hohlraum drive and implosion experiments on Nova. Revision 1

    International Nuclear Information System (INIS)

    Kilkenny, J.D.; Suter, L.J.; Cable, M.D.

    1994-01-01

    Experiments on Nova have demonstrated hohlraum radiation temperatures up to 300 eV and in lower temperature experiments reproducible time integrated symmetry to 1--2%. Detailed 2-D LASNEX simulations satisfactorily reproduce Nova's drive and symmetry scaling data bases. Hohlraums has been used for implosion experiments achieving convergence ratios (initial capsule radius/final fuel radius) up to 24 with high density glass surrounding a hot gas fill

  20. Laser plasma interaction in rugby-shaped hohlraums

    Science.gov (United States)

    Masson-Laborde, P.-E.; Philippe, F.; Tassin, V.; Monteil, M.-C.; Gauthier, P.; Casner, A.; Depierreux, S.; Seytor, P.; Teychenne, D.; Loiseau, P.; Freymerie, P.

    2014-10-01

    Rugby shaped-hohlraum has proven to give high performance compared to a classical similar-diameter cylinder hohlraum. Due to this performance, this hohlraum has been chosen as baseline ignition target for the Laser MegaJoule (LMJ). Many experiments have therefore been performed during the last years on the Omega laser facility in order to study in details the rugby hohlraum. In this talk, we will discuss the interpretation of these experiments from the point of view of the laser plasma instability problem. Experimental comparisons have been done between rugby, cylinder and elliptical shape rugby hohlraums and we will discuss how the geometry differences will affect the evolution of laser plasma instabilities (LPI). The efficiency of laser smoothing techniques on these instabilities will also be discussed as well as gas filling effect. The experimental results will be compared with FCI2 hydroradiative calculations and linear postprocessing with Piranah. Experimental Raman and Brillouin spectrum, from which we can infer the location of the parametric instabilities, will be compared to simulated ones, and will give the possibility to compare LPI between the different hohlraum geometries.

  1. Applying GRADE-CERQual to qualitative evidence synthesis findings-paper 6: how to assess relevance of the data.

    Science.gov (United States)

    Noyes, Jane; Booth, Andrew; Lewin, Simon; Carlsen, Benedicte; Glenton, Claire; Colvin, Christopher J; Garside, Ruth; Bohren, Meghan A; Rashidian, Arash; Wainwright, Megan; Tunςalp, Özge; Chandler, Jacqueline; Flottorp, Signe; Pantoja, Tomas; Tucker, Joseph D; Munthe-Kaas, Heather

    2018-01-25

    The GRADE-CERQual (Confidence in Evidence from Reviews of Qualitative research) approach has been developed by the GRADE (Grading of Recommendations Assessment, Development and Evaluation) Working Group. The approach has been developed to support the use of findings from qualitative evidence syntheses in decision-making, including guideline development and policy formulation. CERQual includes four components for assessing how much confidence to place in findings from reviews of qualitative research (also referred to as qualitative evidence syntheses): (1) methodological limitations, (2) coherence, (3) adequacy of data and (4) relevance. This paper is part of a series providing guidance on how to apply CERQual and focuses on CERQual's relevance component. We developed the relevance component by searching the literature for definitions, gathering feedback from relevant research communities and developing consensus through project group meetings. We tested the CERQual relevance component within several qualitative evidence syntheses before agreeing on the current definition and principles for application. When applying CERQual, we define relevance as the extent to which the body of data from the primary studies supporting a review finding is applicable to the context (perspective or population, phenomenon of interest, setting) specified in the review question. In this paper, we describe the relevance component and its rationale and offer guidance on how to assess relevance in the context of a review finding. This guidance outlines the information required to assess relevance, the steps that need to be taken to assess relevance and examples of relevance assessments. This paper provides guidance for review authors and others on undertaking an assessment of relevance in the context of the CERQual approach. Assessing the relevance component requires consideration of potentially important contextual factors at an early stage in the review process. We expect the CERQual

  2. Hollow wall to stabilize and enhance ignition hohlraums

    Science.gov (United States)

    Vandenboomgaerde, M.; Grisollet, A.; Bonnefille, M.; Clérouin, J.; Arnault, P.; Desbiens, N.; Videau, L.

    2018-01-01

    In the context of the indirect-drive scheme of the inertial-confinement fusion, performance of the gas-filled hohlraums at the National Ignition Facility appears to be reduced. Experiments ascertain a limited efficacy of the laser beam propagation and x-ray conversion. One identified issue is the growth of the gold plasma plume (or bubble) which is generated near the ends of the hohlraum by the impact of the laser beams. This bubble impedes the laser propagation towards the equator of the hohlraum. Furthermore, for high foot or low foot laser pulses, the gold-gas interface of the bubble can be unstable. If this instability should grow to mixing, the x-ray conversion could be degraded. A novel hollow-walled hohlraum is designed, which drastically reduces the growth of the gold bubble and stabilizes the gold-gas interface. The hollow walls are built from the combination of a thin gold foil and a gold domed-wall. We theoretically explain how the bubble expansion can be delayed and the gold-gas interface stabilized. This advanced design lets the laser beams reach the waist of the hohlraum. As a result, the x-ray drive on the capsule is enhanced, and more spherical implosions are obtained. Furthermore, this design only requires intermediate gas fill density to be efficient.

  3. Comprehensive diagnostic set for intense lithium ion hohlraum experiments on PBFA II

    International Nuclear Information System (INIS)

    Leeper, R.J.; Bailey, J.E.; Carlson, A.L.

    1994-01-01

    A review of the comprehensive diagnostic package developed at Sandia National Laboratories for intense lithium ion hohlraum target experiments on PBFA II will be presented. This package contains an extensive suite of x-ray spectral and imaging diagnostics that enable measurements of target radiation smoothing, hydro-motion, and temperature. The x-ray diagnostics include time-integrated and time-resolved pinhole cameras, energy-resolved 1-D streaked imaging diagnostics that enable measurements of target radiation smoothing, hydro-motion, and temperature. The x-ray diagnostics include time-integrated and time-resolved pinhole cameras, energy-resolved 1-D streaked imaging diagnostics, time-integrated and time-resolved grazing incidence spectrographs, a transmission grating spectrography, an elliptical crystal spectrograph, a bolometer array, an eleven element x-ray diode (XRD) array, and an eleven element PIN diode detector array. A hohlraum temperature measurement technique under development is a shock breakout diagnostic that measures the radiation pressure at the hohlraum wall. The incident Li beam symmetry and an estimate of incident Li beam power density are measured from ion beam-induced characteristic x-ray line and neutron emissions. An attempt to measure the Li beam intensity directly on target used Rutherford scattered ions into an ion movie camera and a magnetic spectrograph. The philosophy used in designing all the diagnostics in the set has emphasized redundant and independent measurements of fundamental physical quantities relevant to the performance of the target. Details of each diagnostic, its integration, data reduction procedures, and recent PBFA-II data will be discussed

  4. Electroless plating technology of integral hohlraum Cu target

    International Nuclear Information System (INIS)

    Liu Jiguang; Fu Qu; Wan Xiaobo; Zhou Lan; Xiao Jiang

    2005-01-01

    The electroless plating method of making integral hohlraum Cu target and corrosion-resistant technology of target's surface were researched. The actual process was as follows, choosing plexiglass (PMMA) as arbor, taking cationic activation and electroless plating Cu on the arbor surface, taking arbor surface passivation and chemical etching by C 6 H 5 N 3 solution. The technology is easy to realize and its cost is lower, so it is of great reference value for fabricating other integral hohlraum metal or alloy targets used for inertial confinement fusion study. (author)

  5. Lithium beam characterization of cylindrical PBFA II hohlraum experiments

    International Nuclear Information System (INIS)

    Moats, A.R.; Derzon, M.S.; Chandler, G.A.; Haill, T.A.; Johnson, D.J.; Leeper, R.J.; Ruiz, C.L.; Wenger, D.F.

    1995-01-01

    Sandia National Laboratories is actively engaged in exploring indirect-drive inertial confinement fusion on the Particle Beam Fusion Accelerator (PBFA II) with pulsed-power accelerated lithium ions as the driver. Experiments utilizing cylindrical hohlraum targets were conducted in 1994. Using the incoming ion beam-induced line radiation from titanium wires surrounding these hohlraums, beam profiles during these experiments have been measured and characterized. These data, their comparison/cross-correlation with particle-based beam diagnostics, and an analysis of the beam parameters that most significantly influence target temperature are presented

  6. Soft X-Ray Measurements of Z-Pinch-Driven Vacuum Hohlraums

    International Nuclear Information System (INIS)

    Baker, K.L.; Porter, J.L.; Ruggles, L.E.; Chandler, G.A.; Deeney, Chris; Varas, M.; Moats, Ann; Struve, Ken; Torres, J.; McGurn, J.; Simpson, W.W.; Fehl, D.L.; Chrien, R.E.; Matuska, W.; Idzorek, G.C.

    1999-01-01

    This article reports the experimental characterization of a z-pinch driven-vacuum hohlraum. The authors have measured soft x-ray fluxes of 5 x 10 12 W/cm 2 radiating from the walls of hohlraums which are 2.4--2.5 cm in diameter by 1 cm tall. The x-ray source used to drive these hohlraums was a z-pinch consisting of a 300 wire tungsten array driven by a 2 MA, 100 ns current pulse. In this hohlraum geometry, the z-pinch x-ray source can produce energies in excess of 800 kJ and powers in excess of 100 TW to drive these hohlraums. The x-rays released in these hohlraums represent greater than a factor of 25 in energy and more than a factor of three in x-ray power over previous laboratory-driven hohlraums

  7. Effect of applied pressure on callus formation and its relevance in ...

    African Journals Online (AJOL)

    ... effect of applied pressure on callus formation, cell differentiation and its importance in grafting. Callus was formed earlier in pressure-free explants. The importance of applied pressure in graft formation was indicated by the fusion of callus cells in capped explant experiments. Where callus grew from the edges, a cambium ...

  8. Relevant aspects of a quality assurance program applied to a nuclear power plant operation

    International Nuclear Information System (INIS)

    Fernandez, J.C.

    1987-01-01

    The purpose of this work was to enumerate the most relevant subjects to be taken into account for the elaboration of a Quality Assurance Program aimed to regulate a nuclear power plant operation. At first, it was necessary to point out the relevance that implies the presence of a group of personnel, experienced in quality assurance with enough knowledge on the technical and organizing aspects of the plant. Other aspect to be taken into account was the contemplation of the international requirements, through the International Atomic Energy Agency and of the national requirements that each country had set up by the corresponding regulating agencies. These organizations pointed out the minimum rules that must be followed for the adequate and efficient execution of a program. The Quality Assurance Manual and the program and work procedures constituted the Quality Assurance Program which must be checked as regards its fulfillment by auditors and quality assurance supervisions. (Author)

  9. Mitigation of stimulated Raman scattering in hohlraum plasmas

    International Nuclear Information System (INIS)

    Kline, J L; Montgomery, D S; Rose, H A; Goldman, S R; Froula, D H; Ross, J S; Stevenson, R M; Lushnikov, P M

    2008-01-01

    One aspect of recent research to control Stimulated Raman Scattering (SRS) in hohlraum plasmas is the investigation of risk mitigation strategies for indirect drive inertial confinement fusion. Experimental tests of these strategies, based on prior theoretical and experimental knowledge of SRS, are performed in hohlraum experiments. In the last year, two strategies have been investigated. The first is the use of high Z dopants to reduce SRS backscatter. Forward stimulated Brillouin scattering (FSBS) could lead to beam spray reducing SRS. Since FSBS depends on the electron temperature and thermal effects depend strongly on Z 2 , a small amount of a high Z dopant, 1-2%, can have a large effect. Experiments have been conducted at the Omega laser to test this theory by varying the amount of Xe dopant in neo-pentane gas filled hohlraums. The experimental measurements do show a decrease in SRS backscatter as Xe dopant is added. However, there are still uncertainties regarding the responsible mechanism since increases inverse-Bremsstrahlung absorption of the SRS light may play a role. The second strategy investigated is using high kλ D plasmas to reduce SRS backscatter. Experiments conducted at the Omega laser facility in hohlraum plasmas determined the critical onset intensity for a range of kλ D . A scaling of the critical onset intensity as a function of kλ D has been determined

  10. Language Teacher Cognition in Applied Linguistics Research: Revisiting the Territory, Redrawing the Boundaries, Reclaiming the Relevance

    Science.gov (United States)

    Kubanyiova, Magdalena; Feryok, Anne

    2015-01-01

    Understanding language teachers' "mental lives" (Walberg, 1972), and how these shape and are shaped by the activity of language teaching in diverse sociocultural contexts, has been at the forefront of the sub discipline of applied linguistics that has become known as "language teacher cognition." Although the collective…

  11. Characterization of Blistering and Delamination in Depleted Uranium Hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Biobaum, K. J. M.

    2013-03-01

    Blistering and delamination are the primary failure mechanisms during the processing of depleted uranium (DU) hohlraums. These hohlraums consist of a sputter-deposited DU layer sandwiched between two sputter-deposited layers of gold; a final thick gold layer is electrodeposited on the exterior. The hohlraum is deposited on a copper-coated aluminum mandrel; the Al and Cu are removed with chemical etching after the gold and DU layers are deposited. After the mandrel is removed, blistering and delamination are observed on the interiors of some hohlraums, particularly at the radius region. It is hypothesized that blisters are caused by pinholes in the copper and gold layers; etchant leaking through these holes reaches the DU layer and causes it to oxidize, resulting in a blister. Depending on the residual stress in the deposited layers, blistering can initiate larger-scale delamination at layer interfaces. Scanning electron microscopy indicates that inhomogeneities in the machined aluminum mandrel are replicated in the sputter-deposited copper layer. Furthermore, the Cu layer exhibits columnar growth with pinholes that likely allow etchant to come in contact with the gold layer. Any inhomogeneities or pinholes in this initial gold layer then become nucleation sites for blistering. Using a focused ion beam system to etch through the gold layer and extract a cross-sectional sample for transmission electron microscopy, amorphous, intermixed layers at the gold/DU interfaces are observed. Nanometer-sized bubbles in the sputtered and electrodeposited gold layers are also present. Characterization of the morphology and composition of the deposited layers is the first step in determining modifications to processing parameters, with the goal of attaining a significant improvement in hohlraum yield.

  12. Measuring symmetry of implosions in cryogenic Hohlraums at the NIF using gated x-ray detectors (invited).

    Science.gov (United States)

    Kyrala, G A; Dixit, S; Glenzer, S; Kalantar, D; Bradley, D; Izumi, N; Meezan, N; Landen, O L; Callahan, D; Weber, S V; Holder, J P; Glenn, S; Edwards, M J; Bell, P; Kimbrough, J; Koch, J; Prasad, R; Suter, L; Kline, J L; Kilkenny, J

    2010-10-01

    Ignition of imploding inertial confinement capsules requires, among other things, controlling the symmetry with high accuracy and fidelity. We have used gated x-ray imaging, with 10 μm and 70 ps resolution, to detect the x-ray emission from the imploded core of symmetry capsules at the National Ignition Facility. The measurements are used to characterize the time dependent symmetry and the x-ray bang time of the implosion from two orthogonal directions. These measurements were one of the primary diagnostics used to tune the parameters of the laser and Hohlraum to vary the symmetry and x-ray bang time of the implosion of cryogenically cooled ignition scale deuterium/helium filled plastic capsules. Here, we will report on the successful measurements performed with up to 1.2 MJ of laser energy in a fully integrated cryogenics gas-filled ignition-scale Hohlraum and capsule illuminated with 192 smoothed laser beams. We will describe the technique, the accuracy of the technique, and the results of the variation in symmetry with tuning parameters, and explain how that set was used to predictably tune the implosion symmetry as the laser energy, the laser cone wavelength separation, and the Hohlraum size were increased to ignition scales. We will also describe how to apply that technique to cryogenically layered tritium-hydrogen-deuterium capsules.

  13. Progress of LMJ-relevant implosions experiments on OMEGA

    Directory of Open Access Journals (Sweden)

    Casner A.

    2013-11-01

    Full Text Available In preparation of the first ignition attempts on the Laser Mégajoule (LMJ, an experimental program is being pursued on OMEGA to investigate LMJ-relevant hohlraums. First, radiation temperature levels close to 300 eV were recently achieved in reduced-scale hohlraums with modest backscatter losses. Regarding the baseline target design for fusion experiments on LMJ, an extensive experimental database has also been collected for scaled implosions experiments in both empty and gas-filled rugby-shaped hohlraums. We acquired a full picture of hohlraum energetics and implosion dynamics. Not only did the rugby hohlraums show significantly higher x-ray drive energy over the cylindrical hohlraums, but symmetry control by power balance was demonstrated, as well as high-performance D2 implosions enabling the use of a complete suite of neutrons diagnostics. Charged particle diagnostics provide complementary insights into the physics of these x-ray driven implosions. An overview of these results demonstrates our ability to control the key parameters driving the implosion, lending more confidence in extrapolations to ignition-scale targets.

  14. High Temperature Dynamic Hohlraums on the Pulsed Power Driver Z

    International Nuclear Information System (INIS)

    Armijo, J.; Chandler, G.A.; Cooper, G.; Derzon, M.S.; Fehl, D.; Gilliland, T.; Hawn, R.; Hebron, D.; Hurst, M.; Jobe, D.; Lash, J.; Lazier, S.; Leeper, R.; McGurn, J.; McKenney, J.; Mock, R.; Nash, T.J.; Nielsen, D.; Ruiz, C.; Ryan, P.; Seaman, J.F.; Torres, J.

    1999-01-01

    In the concept of the dynamic hohlraum an imploding z-pinch is optically thick to its own radiation. Radiation may be trapped inside the pinch to give a radiation temperature inside the pinch greater than that outside the pinch. The radiation is typically produced by colliding an outer Z-pinch liner onto an inner liner. The collision generates a strongly radiating shock, and the radiation is trapped by the outer liner. As the implosion continues after the collision the radiation temperature may continue to increase due to ongoing PdV (pressure times change in volume) work done by the implosion. In principal the radiation temperature may increase to the point at which the outer liner burns through, becomes optically thin, and no longer traps the radiation. One application of the dynamic hohlraum is to drive an ICF (inertial confinement fusion) pellet with the trapped radiation field. Members of the dynamic hohlraum team at Sandia National Labs have used the pulsed power driver Z (20 LMA, 100 ns) to create a dynamic hohlraum with temperature linearly ramping from 100 to 180 eV over 5 ns. On this shot zp214 a nested tungsten wire array of 4 and 2 cm diameters with masses of 2 and 1 mg imploded onto a 2.5 mg plastic annulus at 5 mm diameter. The current return can on this shot was slotted. It is likely the radiation temperature may be increased to over 200 CV by stabilizing the pinch with a solid current return can. A current return can with 9 slots imprints 9 filaments onto the imploding pinch. This degrades the optical trapping and the quality of the liner collision. A 1.6 mm diameter capsule situated inside this dynamic hohlraum of zp214 would see 15 kJ of radiation impinging on its surface before the pinch itself collapses to a 1.6 mm diameter. Dynamic hohlraum shots including pellets are scheduled to take place on Z in September of 1998

  15. Simulation of the hohlraum for a laser facility of Megajoule scale

    Energy Technology Data Exchange (ETDEWEB)

    Chizhkov, M N; Kozmanov, M Y U; Lebedev, S N; Lykov, V A; Rykovanova, V V; Seleznev, V N; Selezneva, K I; Stryakhnina, O V; Shestakov, A A; Vronskiy, A V, E-mail: M.N.Chizhkov@VNIITF.r [Russian Federal Nuclear Center - VNIITF Vasilieva str. 13, Snezhinsk, Chelyabinsk reg., 456770 (Russian Federation)

    2010-08-01

    2D calculations of the promising laser hohlraums were performed with using of the Sinara computer code. These hohlraums are intended for achievement of indirectly-driven thermonuclear ignition at laser energy above 1 MJ. Two calculation variants of the laser assembly with the form close to a rugby ball were carried out: with laser entrance hole shields and without shields. Time dependent hohlraum radiation temperature and x-ray flux asymmetry on a target were obtained.

  16. Simulation of the hohlraum for a laser facility of Megajoule scale

    International Nuclear Information System (INIS)

    Chizhkov, M N; Kozmanov, M Y U; Lebedev, S N; Lykov, V A; Rykovanova, V V; Seleznev, V N; Selezneva, K I; Stryakhnina, O V; Shestakov, A A; Vronskiy, A V

    2010-01-01

    2D calculations of the promising laser hohlraums were performed with using of the Sinara computer code. These hohlraums are intended for achievement of indirectly-driven thermonuclear ignition at laser energy above 1 MJ. Two calculation variants of the laser assembly with the form close to a rugby ball were carried out: with laser entrance hole shields and without shields. Time dependent hohlraum radiation temperature and x-ray flux asymmetry on a target were obtained.

  17. Prolate-Spheroid ('Rugby-Shaped') Hohlraum for Inertial Confinement Fusion

    International Nuclear Information System (INIS)

    Vandenboomgaerde, M.; Bastian, J.; Casner, A.; Galmiche, D.; Jadaud, J.-P.; Laffite, S.; Liberatore, S.; Malinie, G.; Philippe, F.

    2007-01-01

    A novel rugby-ball shaped hohlraum is designed in the context of the indirect-drive scheme of inertial-confinement fusion (ICF). Experiments were performed on the OMEGA laser and are the first use of rugby hohlraums for ICF studies. Analysis of experimental data shows that the hohlraum energetics is well understood. We show that the rugby-ball shape exhibits advantages over cylinder, in terms of temperature and of symmetry control of the capsule implosion. Simulations indicate that rugby hohlraum driven targets may be candidates for ignition in a context of early Laser MegaJoule experiments with reduced laser energy

  18. First laser-plasma interaction and hohlraum experiments on the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Dewald, E L; Glenzer, S H; Landen, O L; Suter, L J; Jones, O S; Schein, J; Froula, D; Divol, L; Campbell, K; Schneider, M S; Holder, J; McDonald, J W; Niemann, C; Mackinnon, A J; Hammel, B A [Lawrence Livermore National Laboratory, PO Box 808, Livermore, CA 94550 (United States)

    2005-12-15

    Recently the first laser-plasma interaction and hohlraum experiments have been performed at the National Ignition Facility (NIF) in support of indirect drive inertial confinement fusion designs. The effects of laser beam smoothing by spectral dispersion and polarization smoothing on the intense (2 x 10{sup 15} W cm{sup -2}) beam propagation in gas-filled tubes has been studied at up to 7 mm plasma scales as found in indirect drive gas filled ignition hohlraum designs. These experiments have shown the expected full propagation without filamentation and beam break up when using full laser smoothing. In addition, vacuum hohlraums have been irradiated with laser powers up to 6 TW, 1-9 ns pulse lengths and energies up to 17 kJ to activate several diagnostics, to study the hohlraum radiation temperature scaling with the laser power and hohlraum size, and to make contact with hohlraum experiments performed at the Nova and Omega laser facilities. Subsequently, novel long laser pulse hohlraum experiments have tested models of hohlraum plasma filling and long pulse hohlraum radiation production. The validity of the plasma filling assessment using in analytical models and radiation hydrodynamics calculations with the code LASNEX has been proven in these studies. The comparison of these results with modelling will be discussed.

  19. Radiation-driven hydrodynamics of long pulse hohlraums on the National Ignition Facility

    International Nuclear Information System (INIS)

    Dewald, D L; Landen, O L; Suter, L J; Schein, J; Holder, J.; Campbell, K.; Glenzer, S H.; McDonald, J W.; Niemann, C.; Mackinnon, A J.; Schneider, M S.; Haynam, C.; Hinkel, D.; Hammel, B.A.

    2005-01-01

    The first hohlraum experiments on the National Ignition Facility (NIF) using the first four laser beams have activated the indirect drive experimental capabilities and tested radiation temperature limits imposed by hohlraum plasma filling. Vacuum hohlraums have been irradiated with laser powers up to 6 TW, 1 ns to 9 ns long square pulses and energies of up to 17 kJ to activate several diagnostics, to study the hohlraum radiation temperature scaling with the laser power and hohlraum size, and to make contact with hohlraum experiments performed at the NOVA and Omega laser facilities. Furthermore, for a variety of hohlraum sizes and pulse lengths, the measured x-ray flux shows signatures of plasma filling that coincide with hard x-ray emission from plasma streaming out of the hohlraum. These observations agree with hydrodynamic simulations and with analytical modeling that includes hydrodynamic and coronal radiative losses. The modeling predicts radiation temperature limits on full NIF (1.8 MJ) that are significantly greater than required for ignition hohlraums

  20. Convergent ablation measurements of plastic ablators in gas-filled rugby hohlraums on OMEGA

    Science.gov (United States)

    Casner, A.; Jalinaud, T.; Masse, L.; Galmiche, D.

    2015-10-01

    Indirect-drive implosions experiments were conducted on the Omega Laser Facility to test the performance of uniformly doped plastic ablators for Inertial Confinement Fusion. The first convergent ablation measurements in gas-filled rugby hohlraums are reported. Ignition relevant limb velocities in the range from 150 to 300 μm .n s-1 have been reached by varying the laser drive energy and the initial capsule aspect ratio. The measured capsule trajectory and implosion velocity are in good agreement with 2D integrated simulations and a zero-dimensional modeling of the implosions. We demonstrate experimentally the scaling law for the maximum implosion velocity predicted by the improved rocket model [Y. Saillard, Nucl. Fusion 46, 1017 (2006)] in the high-ablation regime case.

  1. Symmetry control in subscale near-vacuum hohlraums

    Science.gov (United States)

    Turnbull, D.; Berzak Hopkins, L. F.; Le Pape, S.; Divol, L.; Meezan, N.; Landen, O. L.; Ho, D. D.; Mackinnon, A.; Zylstra, A. B.; Rinderknecht, H. G.; Sio, H.; Petrasso, R. D.; Ross, J. S.; Khan, S.; Pak, A.; Dewald, E. L.; Callahan, D. A.; Hurricane, O.; Hsing, W. W.; Edwards, M. J.

    2016-05-01

    Controlling the symmetry of indirect-drive inertial confinement fusion implosions remains a key challenge. Increasing the ratio of the hohlraum diameter to the capsule diameter (case-to-capsule ratio, or CCR) facilitates symmetry tuning. By varying the balance of energy between the inner and outer cones as well as the incident laser pulse length, we demonstrate the ability to tune from oblate, through round, to prolate at a CCR of 3.2 in near-vacuum hohlraums at the National Ignition Facility, developing empirical playbooks along the way for cone fraction sensitivity of various laser pulse epochs. Radiation-hydrodynamic simulations with enhanced inner beam propagation reproduce most experimental observables, including hot spot shape, for a majority of implosions. Specular reflections are used to diagnose the limits of inner beam propagation as a function of pulse length.

  2. Lithium ion beam driven hohlraums for PBFA II

    International Nuclear Information System (INIS)

    Dukart, R.J.

    1994-01-01

    In our light ion inertial confinement fusion (ICF) program, fusion capsules are driven with an intense x-ray radiation field produced when an intense beam of ions penetrates a radiation case and deposits energy in a foam x-ray conversion region. A first step in the program is to generate and measure these intense fields on the Particle Beam Fusion Accelerator II (PBFA II). Our goal is to generate a 100-eV radiation temperature in lithium ion beam driven hohlraums, the radiation environment which will provide the initial drive temperature for ion beam driven implosion systems designed to achieve high gain. In this paper, we describe the design of such hohlraum targets and their predicted performance on PBFA II as we provide increasing ion beam intensities

  3. Impeding hohlraum plasma stagnation in inertial-confinement fusion.

    Science.gov (United States)

    Li, C K; Séguin, F H; Frenje, J A; Rosenberg, M J; Rinderknecht, H G; Zylstra, A B; Petrasso, R D; Amendt, P A; Landen, O L; Mackinnon, A J; Town, R P J; Wilks, S C; Betti, R; Meyerhofer, D D; Soures, J M; Hund, J; Kilkenny, J D; Nikroo, A

    2012-01-13

    This Letter reports the first time-gated proton radiography of the spatial structure and temporal evolution of how the fill gas compresses the wall blowoff, inhibits plasma jet formation, and impedes plasma stagnation in the hohlraum interior. The potential roles of spontaneously generated electric and magnetic fields in the hohlraum dynamics and capsule implosion are discussed. It is shown that interpenetration of the two materials could result from the classical Rayleigh-Taylor instability occurring as the lighter, decelerating ionized fill gas pushes against the heavier, expanding gold wall blowoff. This experiment showed new observations of the effects of the fill gas on x-ray driven implosions, and an improved understanding of these results could impact the ongoing ignition experiments at the National Ignition Facility.

  4. Optimization of the NIF ignition point design hohlraum

    International Nuclear Information System (INIS)

    Callahan, D A; Hinkel, D E; Berger, R L; Divol, L; Dixit, S N; Edwards, M J; Haan, S W; Jones, O S; Lindl, J D; Meezan, N B; Michel, P A; Pollaine, S M; Suter, L J; Town, R P J; Bradley, P A

    2008-01-01

    In preparation for the start of NIF ignition experiments, we have designed a porfolio of targets that span the temperature range that is consistent with initial NIF operations: 300 eV, 285 eV, and 270 eV. Because these targets are quite complicated, we have developed a plan for choosing the optimum hohlraum for the first ignition attempt that is based on this portfolio of designs coupled with early NIF experiements using 96 beams. These early experiments will measure the laser plasma instabilities of the candidate designs and will demonstrate our ability to tune symmetry in these designs. These experimental results, coupled with the theory and simulations that went into the designs, will allow us to choose the optimal hohlraum for the first NIF ignition attempt

  5. Optimization of the NIF ignition point design hohlraum

    Science.gov (United States)

    Callahan, D. A.; Hinkel, D. E.; Berger, R. L.; Divol, L.; Dixit, S. N.; Edwards, M. J.; Haan, S. W.; Jones, O. S.; Lindl, J. D.; Meezan, N. B.; Michel, P. A.; Pollaine, S. M.; Suter, L. J.; Town, R. P. J.; Bradley, P. A.

    2008-05-01

    In preparation for the start of NIF ignition experiments, we have designed a porfolio of targets that span the temperature range that is consistent with initial NIF operations: 300 eV, 285 eV, and 270 eV. Because these targets are quite complicated, we have developed a plan for choosing the optimum hohlraum for the first ignition attempt that is based on this portfolio of designs coupled with early NIF experiements using 96 beams. These early experiments will measure the laser plasma instabilities of the candidate designs and will demonstrate our ability to tune symmetry in these designs. These experimental results, coupled with the theory and simulations that went into the designs, will allow us to choose the optimal hohlraum for the first NIF ignition attempt.

  6. Symmetry control in subscale near-vacuum hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Turnbull, D., E-mail: turnbull2@llnl.gov; Berzak Hopkins, L. F.; Le Pape, S.; Divol, L.; Meezan, N.; Landen, O. L.; Ho, D. D.; Ross, J. S.; Khan, S.; Pak, A.; Dewald, E. L.; Callahan, D. A.; Hurricane, O.; Hsing, W. W.; Edwards, M. J. [National Ignition Facility, LLNL, Livermore, California 94550 (United States); Mackinnon, A. [National Ignition Facility, LLNL, Livermore, California 94550 (United States); Linac Coherent Light Source, SLAC, Menlo Park, California 94025 (United States); Zylstra, A. B. [Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139 (United States); Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Rinderknecht, H. G. [Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139 (United States); National Ignition Facility, LLNL, Livermore, California 94550 (United States); Sio, H.; Petrasso, R. D. [Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139 (United States)

    2016-05-15

    Controlling the symmetry of indirect-drive inertial confinement fusion implosions remains a key challenge. Increasing the ratio of the hohlraum diameter to the capsule diameter (case-to-capsule ratio, or CCR) facilitates symmetry tuning. By varying the balance of energy between the inner and outer cones as well as the incident laser pulse length, we demonstrate the ability to tune from oblate, through round, to prolate at a CCR of 3.2 in near-vacuum hohlraums at the National Ignition Facility, developing empirical playbooks along the way for cone fraction sensitivity of various laser pulse epochs. Radiation-hydrodynamic simulations with enhanced inner beam propagation reproduce most experimental observables, including hot spot shape, for a majority of implosions. Specular reflections are used to diagnose the limits of inner beam propagation as a function of pulse length.

  7. Hohlraums energy balance and x-ray drive

    International Nuclear Information System (INIS)

    Kilkenny, J.D.

    1994-01-01

    For many years there has been an active ICF program in the US concentrating on x-ray drive. X-ray drive is produced by focusing laser beams into a high Z hohlraum. Conceptually, the radiation field comes close to thermodynamic equilibrium, that is it becomes isotropic and Planckian. These properties lead to the benefits of x-ray drive--it is relatively easy to obtain drive symmetry on a capsule with no small scalelengths drive perturbations. Other advantages of x-ray drive is the higher mass ablation rate, leading to lower growth rates for hydrodynamic instabilities. X-ray drive has disadvantages, principally the loss of energy to the walls of the hohlraum. This report is divided into the following sections: (1) review of blackbody radiation; (2) laser absorption and conversion to x-rays; (3) x-ray absorption coefficient in matter and Rosseland mean free path; (4) Marshak waves in high Z material; (5) x-ray albedo; and (6) power balance and hohlraum temperature

  8. Increasing Z-pinch vacuum hohlraum capsule coupling efficiency

    International Nuclear Information System (INIS)

    Callahan, Debbie; Vesey, Roger Alan; Cochrane, Kyle Robert; Nikroo, A.; Bennett, Guy R.; Schroen, Diana Grace; Ruggles, Laurence E.; Porter, John L.; Streit, Jon; Mehlhorn, Thomas Alan; Cuneo, Michael Edward

    2004-01-01

    Symmetric capsule implosions in the double-ended vacuum hohlraum (DEH) on Z have demonstrated convergence ratios of 14-21 for 2.15-mm plastic ablator capsules absorbing 5-7 kJ of x-rays, based on backlit images of the compressed ablator remaining at peak convergence (1). Experiments with DD-filled 3.3-mm diameter capsules designed to absorb 14 kJ of x-rays have begun as an integrated test of drive temperature and symmetry, complementary to thin-shell symmetry diagnostic capsules. These capsule implosions are characterized by excellent control of symmetry (< 3% time-integrated), but low hohlraum efficiency (< 2%). Possible methods to increase the capsule absorbed energy in the DEH include mixed-component hohlraums, large diameter foam ablator capsules, transmissive shine shields between the z-pinch and capsule, higher spoke electrode x-ray transmission, a double-sided power feed, and smaller initial radius z-pinch wire arrays. Simulations will explore the potential for each of these modifications to increase the capsule coupling efficiency for near-term experiments on Z and ZR

  9. Numerical investigation on target implosions driven by radiation ablation and shock compression in dynamic hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Delong; Sun, Shunkai; Zhao, Yingkui; Ding, Ning; Wu, Jiming; Dai, Zihuan; Yin, Li; Zhang, Yang; Xue, Chuang [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)

    2015-05-15

    In a dynamic hohlraum driven inertial confinement fusion (ICF) configuration, the target may experience two different kinds of implosions. One is driven by hohlraum radiation ablation, which is approximately symmetric at the equator and poles. The second is caused by the radiating shock produced in Z-pinch dynamic hohlraums, only taking place at the equator. To gain a symmetrical target implosion driven by radiation ablation and avoid asymmetric shock compression is a crucial issue in driving ICF using dynamic hohlraums. It is known that when the target is heated by hohlraum radiation, the ablated plasma will expand outward. The pressure in the shocked converter plasma qualitatively varies linearly with the material temperature. However, the ablation pressure in the ablated plasma varies with 3.5 power of the hohlraum radiation temperature. Therefore, as the hohlraum temperature increases, the ablation pressure will eventually exceed the shock pressure, and the expansion of the ablated plasma will obviously weaken the shock propagation and decrease its velocity after propagating into the ablator plasma. Consequently, longer time duration is provided for the symmetrical target implosion driven by radiation ablation. In this paper these processes are numerically investigated by changing drive currents or varying load parameters. The simulation results show that a critical hohlraum radiation temperature is needed to provide a high enough ablation pressure to decelerate the shock, thus providing long enough time duration for the symmetric fuel compression driven by radiation ablation.

  10. The near vacuum hohlraum campaign at the NIF: A new approach

    Energy Technology Data Exchange (ETDEWEB)

    Le Pape, S.; Berzak Hopkins, L. F.; Divol, L.; Meezan, N.; Turnbull, D.; Ho, D.; Ross, J. S.; Khan, S.; Pak, A.; Dewald, E.; Benedetti, L. R.; Nagel, S.; Biener, J.; Callahan, D. A.; Yeamans, C.; Michel, P.; Schneider, M.; Kozioziemski, B.; Ma, T.; Macphee, A. G. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); and others

    2016-05-15

    The near vacuum campaign on the National Ignition Facility has concentrated its efforts over the last year on finding the optimum target geometry to drive a symmetric implosion at high convergence ratio (30×). As the hohlraum walls are not tamped with gas, the hohlraum is filling with gold plasma and the challenge resides in depositing enough energy in the hohlraum before it fills up. Hohlraum filling is believed to cause symmetry swings late in the pulse that are detrimental to the symmetry of the hot spot at high convergence. This paper describes a series of experiments carried out to examine the effect of increasing the distance between the hohlraum wall and the capsule (case to capsule ratio) on the symmetry of the hot spot. These experiments have shown that smaller Case to Capsule Ratio (CCR of 2.87 and 3.1) resulted in oblate implosions that could not be tuned round. Larger CCR (3.4) led to a prolate implosion at convergence 30× implying that inner beam propagation at large CCR is not impeded by the expanding hohlraum plasma. A Case to Capsule ratio of 3.4 is a promising geometry to design a round implosion but in a smaller hohlraum where the hohlraum losses are lower, enabling a wider cone fraction range to adjust symmetry.

  11. The near vacuum hohlraum campaign at the NIF: A new approach

    Science.gov (United States)

    Le Pape, S.; Berzak Hopkins, L. F.; Divol, L.; Meezan, N.; Turnbull, D.; Mackinnon, A. J.; Ho, D.; Ross, J. S.; Khan, S.; Pak, A.; Dewald, E.; Benedetti, L. R.; Nagel, S.; Biener, J.; Callahan, D. A.; Yeamans, C.; Michel, P.; Schneider, M.; Kozioziemski, B.; Ma, T.; Macphee, A. G.; Haan, S.; Izumi, N.; Hatarik, R.; Sterne, P.; Celliers, P.; Ralph, J.; Rygg, R.; Strozzi, D.; Kilkenny, J.; Rosenberg, M.; Rinderknecht, H.; Sio, H.; Gatu-Johnson, M.; Frenje, J.; Petrasso, R.; Zylstra, A.; Town, R.; Hurricane, O.; Nikroo, A.; Edwards, M. J.

    2016-05-01

    The near vacuum campaign on the National Ignition Facility has concentrated its efforts over the last year on finding the optimum target geometry to drive a symmetric implosion at high convergence ratio (30×). As the hohlraum walls are not tamped with gas, the hohlraum is filling with gold plasma and the challenge resides in depositing enough energy in the hohlraum before it fills up. Hohlraum filling is believed to cause symmetry swings late in the pulse that are detrimental to the symmetry of the hot spot at high convergence. This paper describes a series of experiments carried out to examine the effect of increasing the distance between the hohlraum wall and the capsule (case to capsule ratio) on the symmetry of the hot spot. These experiments have shown that smaller Case to Capsule Ratio (CCR of 2.87 and 3.1) resulted in oblate implosions that could not be tuned round. Larger CCR (3.4) led to a prolate implosion at convergence 30× implying that inner beam propagation at large CCR is not impeded by the expanding hohlraum plasma. A Case to Capsule ratio of 3.4 is a promising geometry to design a round implosion but in a smaller hohlraum where the hohlraum losses are lower, enabling a wider cone fraction range to adjust symmetry.

  12. Rugby and elliptical-shaped hohlraums experiments on the OMEGA laser facility

    Science.gov (United States)

    Tassin, Veronique; Monteil, Marie-Christine; Depierreux, Sylvie; Masson-Laborde, Paul-Edouard; Philippe, Franck; Seytor, Patricia; Fremerye, Pascale; Villette, Bruno

    2017-10-01

    We are pursuing on the OMEGA laser facility indirect drive implosions experiments in gas-filled rugby-shaped hohlraums in preparation for implosion plateforms on LMJ. The question of the precise wall shape of rugby hohlraum has been addressed as part of future megajoule-scale ignition designs. Calculations show that elliptical-shaped holhraum is more efficient than spherical-shaped hohlraum. There is less wall hydrodynamics and less absorption for the inner cone, provided a better control of time-dependent symmetry swings. In this context, we have conducted a series of experiments on the OMEGA laser facility. The goal of these experiments was therefore to characterize energetics with a complete set of laser-plasma interaction measurements and capsule implosion in gas-filled elliptical-shaped hohlraum with comparison with spherical-shaped hohlraum. Experiments results are discussed and compared to FCI2 radiation hydrodynamics simulations.

  13. Demonstration of Enhanced Radiation Drive in Hohlraums Made from a Mixture of High-Z Wall Materials

    International Nuclear Information System (INIS)

    Schein, Jochen; Jones, Ogden; Rosen, Mordecai; Dewald, Eduard; Glenzer, Siegfried; Gunther, Janelle; Hammel, Bruce; Landen, Otto; Suter, Laurence; Wallace, Russell

    2007-01-01

    We present results from experiments, numerical simulations and analytic modeling, demonstrating enhanced hohlraum performance. Care in the fabrication and handling of hohlraums with walls consisting of high-Z mixtures (cocktails) has led to our demonstration, for the first time, of a significant increase in radiation temperature compared to a pure Au hohlraum that is in agreement with predictions and is ascribable to reduced wall losses. The data suggest that a National Ignition Facility ignition hohlraum made of a U:Au:Dy cocktail should have ∼17% reduction in wall losses compared to a similar gold hohlraum

  14. FABRICATION OF WINDOW SADDLES FOR NIF CRYOGENIC HOHLRAUMS

    International Nuclear Information System (INIS)

    GIRALDEZ, E; KAAE, J.L

    2003-09-01

    OAK-B135 A planar diagnostic viewing port attached to the cylindrical wall of the NIF cryogenic hohlraum requires a saddle-like transition piece. While the basic design of this window saddle is straightforward, its fabrication is not, given the scale and precision of the component. They solved the problem through the use of a two segment copper mandrel to electroform the gold window saddle. The segments were micro-machined using a combination of single-point diamond turning and single point diamond milling. These processes as well as the electroplating conditions, final machining and mandrel removal are described in this paper

  15. Gas-filled hohlraum experiments at the national ignition facility.

    Energy Technology Data Exchange (ETDEWEB)

    Fernández, J. C. (Juan C.); Gautier, D. C. (Donald Cort); Goldman, S. R. (Sanford R.); Grimm, B. M.; Hegelich, B. M. (Bjorn M.); Kline, J. L. (John L.); Montgomery, D. S. (David S.); Lanier, N. E. (Nicholas E.); Rose, H. A. (Harvey A.); Schmidt, D. M. (David M.); Swift, D. C.; Workman, J. B. (Jonathan B.); Alvarez, Sharon; Bower, Dan.; Braun, Dave.; Campbell, K. (Katherine); DeWald, E.; Glenzer, S. (Siegfried); Holder, J. (Joe P.); Kamperschroer, J. H. (James H.); Kimbrough, Joe (Joseph R.); Kirkwood, Robert (Bob); Landen, O. L. (Otto L.); Mccarville, Tom (Tomas J.); Macgowan, B.; Mackinnon, A.; Niemann, C.; Schein, J.; Schneider, M; Watts, Phil; Young, Ben-li [number : znumber] 194154; Young B.

    2004-01-01

    The summary of this paper is: (1) We have fielded on NIF a gas-filled hohlraum designed for future ignition experiments; (2) Wall-motion measurements are consistent with LASNEX simulations; (3) LPI back-scattering results have confounded expectations - (a) Stimulated Brillouin (SBS) dominates Raman (SRS) for any gas-fill species, (b) Measured SBS time-averaged reflectivity values are high, peak values are even higher, (c) SRS and SBS peak while laser-pulse is rising; and (4) Plasma conditions at the onset of high back-scattering yield high SBS convective linear gain - Wavelengths of the back-scattered light is predicted by linear theory.

  16. Hohlraum Radiation Drive Measurements on the Omega Laser

    International Nuclear Information System (INIS)

    Decker, C.; Turner, R.E.; Landen, O.L.; Suter, L.J.; Amendt, P.; Kornblum, H.N.; Hammel, B.A.; Murphy, T.J.; Wallace, J.; Delamater, N.D.; Gobby, P.; Hauer, A.A.; Magelssen, G.R.; Oertel, J.A.; Knauer, J.; Marshall, F.J.; Bradley, D.; Seka, W.; Soures, J.M.

    1997-01-01

    Time-resolved drive measurements with thin-walled hohlraum targets on Omega [J.M.Soures et al., Phys.Plasmas 3, 2108 (1996)] are presented and compared with two-dimensional hydrodynamical simulations. For the first time, radiation fluxes are measured through the laser entrance hole instead of through a diagnostic side hole. We find improved agreement between time dependent experiments and simulations using this new technique. In addition, the drive history obtained in this manner correlates well with the drive onto the capsule at target center. copyright 1997 The American Physical Society

  17. Gas-filled hohlraum experiments at the national ignition facility

    International Nuclear Information System (INIS)

    Fernandez, J.C.; Gautier, D.C.; Goldman, S.R.; Grimm, B.M.; Hegelich, B.M.; Kline, J.L.; Montgomery, D.S.; Lanier, N.E.; Rose, H.A.; Schmidt, D.M.; Swift, D.C.; Workman, J.B.; Alvarez, Sharon; Bower, Dan; Braun, Dave; Campbell, K.; DeWald, E.; Glenzer, S.; Holder, J.; Kamperschroer, J.H.; Kimbrough, Joe; Kirkwood, Robert; Landen, O.L.; Mccarville, Tom; Macgowan, B.; Mackinnon, A.; Niemann, C.; Schein, J.; Schneider, M.; Watts, Phil; Young, Ben-li; Young B.

    2004-01-01

    The summary of this paper is: (1) We have fielded on NIF a gas-filled hohlraum designed for future ignition experiments; (2) Wall-motion measurements are consistent with LASNEX simulations; (3) LPI back-scattering results have confounded expectations - (a) Stimulated Brillouin (SBS) dominates Raman (SRS) for any gas-fill species, (b) Measured SBS time-averaged reflectivity values are high, peak values are even higher, (c) SRS and SBS peak while laser-pulse is rising; and (4) Plasma conditions at the onset of high back-scattering yield high SBS convective linear gain - Wavelengths of the back-scattered light is predicted by linear theory.

  18. First demonstration of improving laser propagation inside the spherical hohlraums by using the cylindrical laser entrance hole

    Directory of Open Access Journals (Sweden)

    Wenyi Huo

    2016-01-01

    Full Text Available The octahedral spherical hohlraums have natural superiority in maintaining high radiation symmetry during the entire capsule implosion process in indirect drive inertial confinement fusion. While, in contrast to the cylindrical hohlraums, the narrow space between the laser beams and the spherical hohlraum wall is usually commented. In this Letter, we address this crucial issue and report our experimental work conducted on the SGIII-prototype laser facility which unambiguously demonstrates that a simple design of cylindrical laser entrance hole (LEH can dramatically improve the laser propagation inside the spherical hohlraums. In addition, the laser beam deflection in the hohlraum is observed for the first time in the experiments. Our 2-dimensional simulation results also verify qualitatively the advantages of the spherical hohlraums with cylindrical LEHs. Our results imply the prospect of adopting the cylindrical LEHs in future spherical ignition hohlraum design.

  19. The relationship between gas fill density and hohlraum drive performance at the National Ignition Facility

    Science.gov (United States)

    Hall, G. N.; Jones, O. S.; Strozzi, D. J.; Moody, J. D.; Turnbull, D.; Ralph, J.; Michel, P. A.; Hohenberger, M.; Moore, A. S.; Landen, O. L.; Divol, L.; Bradley, D. K.; Hinkel, D. E.; Mackinnon, A. J.; Town, R. P. J.; Meezan, N. B.; Berzak Hopkins, L.; Izumi, N.

    2017-05-01

    Indirect drive inertial confinement fusion experiments were conducted at the National Ignition Facility to investigate the performance of the hohlraum drive as a function of hohlraum gas fill density by imploding high-density-carbon capsules using a 2-shock laser pulse. Measurements characterized the backscatter behavior, the production of hot electrons, the motion and brightness of the laser spots on the hohlraum wall, and the efficiency of the hohlraum x-ray drive as a function of gas fill density ρgf between 0.03 mg/cc ("near vacuum") and 1.6 mg/cc. For hohlraums with ρgf up to 0.85 mg/cc, very little stimulated Raman backscatter (SRS) was observed. For higher ρgf, significant SRS was produced and was observed to occur during the rise to peak laser power and throughout the main pulse. The efficiency with which laser energy absorbed by the hohlraum is converted into drive energy was measured to be the same for ρgf ≥ 0.6 mg/cc once the laser reached peak power. However, for the near vacuum case, the absorbed energy was converted to drive energy more efficiently throughout the pulse and maintained an efficiency ˜10% higher than the gas filled hohlraums throughout the main pulse.

  20. First Octahedral Spherical Hohlraum Energetics Experiment at the SGIII Laser Facility

    Science.gov (United States)

    Huo, Wen Yi; Li, Zhichao; Chen, Yao-Hua; Xie, Xufei; Ren, Guoli; Cao, Hui; Li, Shu; Lan, Ke; Liu, Jie; Li, Yongsheng; Li, Sanwei; Guo, Liang; Liu, Yonggang; Yang, Dong; Jiang, Xiaohua; Hou, Lifei; Du, Huabing; Peng, Xiaoshi; Xu, Tao; Li, Chaoguang; Zhan, Xiayu; Wang, Zhebin; Deng, Keli; Wang, Qiangqiang; Deng, Bo; Wang, Feng; Yang, Jiamin; Liu, Shenye; Jiang, Shaoen; Yuan, Guanghui; Zhang, Haijun; Jiang, Baibin; Zhang, Wei; Gu, Qianqian; He, Zhibing; Du, Kai; Deng, Xuewei; Zhou, Wei; Wang, Liquan; Huang, Xiaoxia; Wang, Yuancheng; Hu, Dongxia; Zheng, Kuixing; Zhu, Qihua; Ding, Yongkun

    2018-04-01

    The first octahedral spherical hohlraum energetics experiment is accomplished at the SGIII laser facility. For the first time, the 32 laser beams are injected into the octahedral spherical hohlraum through six laser entrance holes. Two techniques are used to diagnose the radiation field of the octahedral spherical hohlraum in order to obtain comprehensive experimental data. The radiation flux streaming out of laser entrance holes is measured by six flat-response x-ray detectors (FXRDs) and four M -band x-ray detectors, which are placed at different locations of the SGIII target chamber. The radiation temperature is derived from the measured flux of FXRD by using the blackbody assumption. The peak radiation temperature inside hohlraum is determined by the shock wave technique. The experimental results show that the octahedral spherical hohlraum radiation temperature is in the range of 170-182 eV with drive laser energies of 71 kJ to 84 kJ. The radiation temperature inside the hohlraum determined by the shock wave technique is about 175 eV at 71 kJ. For the flat-top laser pulse of 3 ns, the conversion efficiency of gas-filled octahedral spherical hohlraum from laser into soft x rays is about 80% according to the two-dimensional numerical simulation.

  1. Characterization of diagnostic hole-closure in Z-pinch driven hohlraums

    International Nuclear Information System (INIS)

    Baker, K. L.; Porter, J. L.; Ruggles, L. E.; Chandler, G. A.; Deeney, Chris; Vargas, M.; Moats, Ann; Struve, Ken; Torres, J.; McGurn, J. S.

    2000-01-01

    In this article we investigate the partial closure of diagnostic holes in Z-pinch driven hohlraums. These hohlraums differ from current laser-driven hohlraums in a number of ways such as their larger size, greater x-ray drive energy, and lower temperature. Although the diameter of the diagnostic holes on these Z-pinch driven hohlraums can be much greater than their laser-driven counterparts, 4 mm in diameter or larger, radiation impinges on the wall material surrounding the hole for the duration of the Z pinch, nearly 100 ns. This incident radiation causes plasma to ablate from the hohlraum walls surrounding the diagnostic hole and partially obscure this diagnostic hole. This partial obscuration reduces the effective area over which diagnostics view the hohlraum's radiation. This reduction in area can lead to an underestimation of the wall temperature when nonimaging diagnostics such as x-ray diodes and bolometers are used to determine power and later to infer a wall temperature. In this article we describe the techniques used to characterize the hole-closure in these hohlraums and present the experimental measurements of this process. (c) 2000 American Institute of Physics

  2. Characterization of diagnostic hole-closure in Z-pinch driven hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Baker, K. L. [Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States); Porter, J. L. [Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States); Ruggles, L. E. [Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States); Chandler, G. A. [Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States); Deeney, Chris [Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States); Vargas, M. [Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States); Moats, Ann [Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States); Struve, Ken [Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States); Torres, J. [Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States); McGurn, J. S. [Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States)] (and others)

    2000-02-01

    In this article we investigate the partial closure of diagnostic holes in Z-pinch driven hohlraums. These hohlraums differ from current laser-driven hohlraums in a number of ways such as their larger size, greater x-ray drive energy, and lower temperature. Although the diameter of the diagnostic holes on these Z-pinch driven hohlraums can be much greater than their laser-driven counterparts, 4 mm in diameter or larger, radiation impinges on the wall material surrounding the hole for the duration of the Z pinch, nearly 100 ns. This incident radiation causes plasma to ablate from the hohlraum walls surrounding the diagnostic hole and partially obscure this diagnostic hole. This partial obscuration reduces the effective area over which diagnostics view the hohlraum's radiation. This reduction in area can lead to an underestimation of the wall temperature when nonimaging diagnostics such as x-ray diodes and bolometers are used to determine power and later to infer a wall temperature. In this article we describe the techniques used to characterize the hole-closure in these hohlraums and present the experimental measurements of this process. (c) 2000 American Institute of Physics.

  3. Rugby-like hohlraum experimental designs for demonstrating x-ray drive enhancement

    Science.gov (United States)

    Amendt, Peter; Cerjan, C.; Hinkel, D. E.; Milovich, J. L.; Park, H.-S.; Robey, H. F.

    2008-01-01

    A suite of experimental designs for the Omega laser facility [Boehly et al., Opt. Commun. 133, 495 (1997)] using rugby and cylindrical hohlraums is proposed to confirm the energetics benefits of rugby-shaped hohlraums over cylinders under optimal implosion symmetry conditions. Postprocessed Dante x-ray drive measurements predict a 12-17eV (23%-36%) peak hohlraum temperature (x-ray flux) enhancement for a 1ns flattop laser drive history. Simulated core self-emission x-ray histories also show earlier implosion times by 200-400ps, depending on the hohlraum case-to-capsule ratio and laser-entrance-hole size. Capsules filled with 10 or 50atm of deuterium (DD) are predicted to give in excess of 1010 neutrons in two-dimensional hohlraum simulations in the absence of mix, enabling DD burn history measurements for the first time in indirect-drive on Omega. Capsule designs with 50atm of DHe3 are also proposed to make use of proton slowing for independently verifying the drive benefits of rugby hohlraums. Scale-5/4 hohlraum designs are also introduced to provide further margin to potential laser-plasma-induced backscatter and hot-electron production.

  4. Rugby-like hohlraum experimental designs for demonstrating x-ray drive enhancement

    International Nuclear Information System (INIS)

    Amendt, Peter; Cerjan, C.; Hinkel, D. E.; Milovich, J. L.; Park, H.-S.; Robey, H. F.

    2008-01-01

    A suite of experimental designs for the Omega laser facility [Boehly et al., Opt. Commun. 133, 495 (1997)] using rugby and cylindrical hohlraums is proposed to confirm the energetics benefits of rugby-shaped hohlraums over cylinders under optimal implosion symmetry conditions. Postprocessed Dante x-ray drive measurements predict a 12-17 eV (23%-36%) peak hohlraum temperature (x-ray flux) enhancement for a 1 ns flattop laser drive history. Simulated core self-emission x-ray histories also show earlier implosion times by 200-400 ps, depending on the hohlraum case-to-capsule ratio and laser-entrance-hole size. Capsules filled with 10 or 50 atm of deuterium (DD) are predicted to give in excess of 10 10 neutrons in two-dimensional hohlraum simulations in the absence of mix, enabling DD burn history measurements for the first time in indirect-drive on Omega. Capsule designs with 50 atm of D 3 He are also proposed to make use of proton slowing for independently verifying the drive benefits of rugby hohlraums. Scale-5/4 hohlraum designs are also introduced to provide further margin to potential laser-plasma-induced backscatter and hot-electron production

  5. Cylindrical target Li-beam-driven hohlraum experiments

    International Nuclear Information System (INIS)

    Derzon, M.S.; Aubert, J.; Chandler, G.A.

    1998-06-01

    The authors performed a series of experiments on the Particle Beam Fusion Accelerator II (PBFA II) in May, 1994, and obtained a brightness temperature of 61 ± 2 eV for an ion-beam heated hohlraum. The hohlraum was a 4-mm-diameter, right-circular cylinder with a 1.5-mm-thick gold wall, a low-density CH foam fill, and a 1.5- or 3-mm-diameter diagnostic aperture in the top. The nominal parameters of the radially-incident PBFA II Li ion beam were 9 MeV peak energy (∼10 MeV at the gas cell) at the target at a peak power of 2.5 ± 0.3 TW/cm 2 and a 15 ns pulse width. Azimuthal variations in intensity of a factor of 3, with respect to the mean, were observed. Nonuniformities in thermal x-ray emission across the area of the diagnostic hole were also observed. Time-dependent hole-closure velocities were measured: the time-averaged velocity of ∼2 cm/micros is in good agreement with sound speed estimates. Unfolded x-ray spectra and brightness temperatures as a function of time are reported and compared to simulations. Hole closure corrections are discussed with comparisons between XRD and bolometer measurements. Temperature scaling with power on target is also presented

  6. Dynamic hohlraum and ICF pellet implosion experiments on Z

    International Nuclear Information System (INIS)

    Nash, T.J.; Derzon, M.S.; Chandler, G.A.

    1999-01-01

    By stabilizing an imploding z-pinch on Z (20 MA, 100 ns) with a solid current return can and a nested wire array the authors have achieved dynamic hohlraum radiation temperatures over 200 eV at a diameter of approximately 1 mm. The pinch configuration yielding this temperature is a nested tungsten wire array of 240 and 120 wires at 4 and 2 cm diameters weighing 2 and 1 mg, 1 cm long, imploding onto a 5 mm diameter, 14 mg/cc cylindrical CH foam, weighing 3 mg. They have used a single 4 cm diameter tungsten wire array to drive a 1.6 mm diameter ICF capsule mounted in a 6 mg/cc foam inside a 3 mg copper annulus at 5 mm diameter, and measured x-ray emissions indicative of the pellet implosion. Mounting the pellet in foam may have caused the hohlraum to become equator-hot. They will present results from upcoming pellet experiments in which the pellet is mounted by thread and driven by a larger diameter, 6 or 7 mm, copper annulus to improve radiation drive symmetry. They will also discuss designs for tapered foam annular targets that distort a cylindrical pinch into a quasi-sphere that will wrap around an ICF pellet to further improve drive symmetry

  7. Studies on radiation symmetrization in heavy-ion driven hohlraum targets

    International Nuclear Information System (INIS)

    Temporal, M.; Atzeni, S.

    1993-01-01

    Radiation symmetrization within spherical, ellipsoidal and cylindral hohlraum targets for heavy ion inertial confinement fusion (ICF) is studied by means of a 3-D numerical, static model, in which realistic assumptions are made concerning the geometry of the system and, particularly, of the radiation converters. Among the systems so far studied, only spherical hohlraums with six converters achieve the illumination symmetry of the fusion capsule considered necessary for ICF applications. A parametric study of cylindrical hohlraums enlightens the effect of several parameter changes, and suggests directions for further studies, aiming at the design of two-converter targets

  8. Green frequency-doubled laser-beam propagation in high-temperature hohlraum plasmas.

    Science.gov (United States)

    Niemann, C; Berger, R L; Divol, L; Froula, D H; Jones, O; Kirkwood, R K; Meezan, N; Moody, J D; Ross, J; Sorce, C; Suter, L J; Glenzer, S H

    2008-02-01

    We demonstrate propagation and small backscatter losses of a frequency-doubled (2omega) laser beam interacting with inertial confinement fusion hohlraum plasmas. The electron temperature of 3.3 keV, approximately a factor of 2 higher than achieved in previous experiments with open geometry targets, approaches plasma conditions of high-fusion yield hohlraums. In this new temperature regime, we measure 2omega laser-beam transmission approaching 80% with simultaneous backscattering losses of less than 10%. These findings suggest that good laser coupling into fusion hohlraums using 2omega light is possible.

  9. Experimental Demonstration of X-Ray Drive Enhancement with Rugby-Shaped Hohlraums

    International Nuclear Information System (INIS)

    Philippe, F.; Casner, A.; Caillaud, T.; Landoas, O.; Monteil, M. C.; Liberatore, S.; Park, H. S.; Amendt, P.; Robey, H.; Sorce, C.; Li, C. K.; Seguin, F.; Rosenberg, M.; Petrasso, R.; Glebov, V.; Stoeckl, C.

    2010-01-01

    Rugby-shaped hohlraums have been suggested as a way to enhance x-ray drive in the indirect drive approach to inertial confinement fusion. This Letter presents an experimental comparison of rugby-shaped and cylinder hohlraums used for D 2 and D 3 He-filled capsules implosions on the Omega laser facility, demonstrating an increase of x-ray flux by 18% in rugby-shaped hohlraums. The highest yields to date for deuterium gas implosions in indirect drive on Omega (1.5x10 10 neutrons) were obtained, allowing for the first time the measurement of a DD burn history. Proton spectra measurements provide additional validation of the higher drive in rugby-shaped hohlraums.

  10. Experimental Demonstration of X-Ray Drive Enhancement with Rugby-Shaped Hohlraums

    Science.gov (United States)

    Philippe, F.; Casner, A.; Caillaud, T.; Landoas, O.; Monteil, M. C.; Liberatore, S.; Park, H. S.; Amendt, P.; Robey, H.; Sorce, C.; Li, C. K.; Seguin, F.; Rosenberg, M.; Petrasso, R.; Glebov, V.; Stoeckl, C.

    2010-01-01

    Rugby-shaped hohlraums have been suggested as a way to enhance x-ray drive in the indirect drive approach to inertial confinement fusion. This Letter presents an experimental comparison of rugby-shaped and cylinder hohlraums used for D2 and DHe3-filled capsules implosions on the Omega laser facility, demonstrating an increase of x-ray flux by 18% in rugby-shaped hohlraums. The highest yields to date for deuterium gas implosions in indirect drive on Omega (1.5×1010 neutrons) were obtained, allowing for the first time the measurement of a DD burn history. Proton spectra measurements provide additional validation of the higher drive in rugby-shaped hohlraums.

  11. Characterizing Hohlraum Plasma Conditions at the National Ignition Facility (NIF) Using X-ray Spectroscopy

    Science.gov (United States)

    Barrios, Maria Alejandra

    2015-11-01

    Improved hohlraums will have a significant impact on increasing the likelihood of indirect drive ignition at the NIF. In indirect-drive Inertial Confinement Fusion (ICF), a high-Z hohlraum converts laser power into a tailored x-ray flux that drives the implosion of a spherical capsule filled with D-T fuel. The x-radiation drive to capsule coupling sets the velocity, adiabat, and symmetry of the implosion. Previous experiments in gas-filled hohlraums determined that the laser-hohlraum energy coupling is 20-25% less than modeled, therefore identifying energy loss mechanisms that reduce the efficacy of the hohlraum drive is central to improving implosion performance. Characterizing the plasma conditions, particularly the plasma electron temperature (Te) , is critical to understanding mechanism that affect the energy coupling such as the laser plasma interactions (LPI), hohlraum x-ray conversion efficiency, and dynamic drive symmetry. The first Te measurements inside a NIF hohlraum, presented here, were achieved using K-shell X-ray spectroscopy of an Mn-Co tracer dot. The dot is deposited on a thin-walled CH capsule, centered on the hohlraum symmetry axis below the laser entrance hole (LEH) of a bottom-truncated hohlraum. The hohlraum x-ray drive ablates the dot and causes it to flow upward, towards the LEH, entering the hot laser deposition region. An absolutely calibrated streaked spectrometer with a line of sight into the LEH records the temporal history of the Mn and Co X-ray emission. The measured (interstage) Lyα/ Heα line ratios for Co and Mn and the Mn-Heα/Co-Heα isoelectronic line ratio are used to infer the local plasma Te from the atomic physics code SCRAM. Time resovled x-ray images perpendicular to the hohlraum axis record the dot expansion and trajectory into the LEH region. The temporal evolution of the measured Te and dot trajectory are compared with simulations from radiation-hydrodynamic codes. This work was performed under the auspices of the U

  12. Experimental results and modeling of a dynamic hohlraum on SATURN

    International Nuclear Information System (INIS)

    Derzon, M.S.; Allshouse, G.O.; Deeney, C.; Leeper, R.J.; Nash, T.J.; Matuska, W.; Peterson, D.L.; MacFarlane, J.J.; Ryutov, D.D.

    1998-06-01

    Experiments were performed at SATURN, a high current z-pinch, to explore the feasibility of creating a hohlraum by imploding a tungsten wire array onto a low-density foam. Emission measurements in the 200--280 eV energy band were consistent with a 110--135 eV Planckian before the target shock heated, or stagnated, on-axis. Peak pinch radiation temperatures of nominally 160 eV were obtained. Measured early time x-ray emission histories and temperature estimates agree well with modeled performance in the 200--280 eV band using a 2D radiation magneto-hydrodynamics code. However, significant differences are observed in comparisons of the x-ray images and 2D simulations

  13. Use of d-3He proton spectroscopy as a diagnostic of shell rho r in capsule implosion experiments with approximately 0.2 NIF scale high temperature Hohlraums at Omega.

    Science.gov (United States)

    Delamater, N D; Wilson, D C; Kyrala, G A; Seifter, A; Hoffman, N M; Dodd, E; Singleton, R; Glebov, V; Stoeckl, C; Li, C K; Petrasso, R; Frenje, J

    2008-10-01

    We present the calculations and preliminary results from experiments on the Omega laser facility using d-(3)He filled plastic capsule implosions in gold Hohlraums. These experiments aim to develop a technique to measure shell rho r and capsule unablated mass with proton spectroscopy and will be applied to future National Ignition Facility (NIF) experiments with ignition scale capsules. The Omega Hohlraums are 1900 microm length x 1200 microm diameter and have a 70% laser entrance hole. This is approximately a 0.2 NIF scale ignition Hohlraum and reaches temperatures of 265-275 eV similar to those during the peak of the NIF drive. These capsules can be used as a diagnostic of shell rho r, since the d-(3)He gas fill produces 14.7 MeV protons in the implosion, which escape through the shell and produce a proton spectrum that depends on the integrated rho r of the remaining shell mass. The neutron yield, proton yield, and spectra change with capsule shell thickness as the unablated mass or remaining capsule rho r changes. Proton stopping models are used to infer shell unablated mass and shell rho r from the proton spectra measured with different filter thicknesses. The experiment is well modeled with respect to Hohlraum energetics, neutron yields, and x-ray imploded core image size, but there are discrepancies between the observed and simulated proton spectra.

  14. Development of a Z-pinch-driven ICF hohlraum concept on Z

    International Nuclear Information System (INIS)

    Cuneo, M.E.; Porter, J.L. Jr.; Vesey, R.A.

    1999-01-01

    Recent development of high power z-pinches (> 150 MW) on the Z driver has permitted the study of high-temperature, radiation-driven hohlraums. Three complementary, Z-pinch source-hohlraum-ICF capsule configurations are being developed to harness the x-ray output of these Z-pinch's. These are the dynamic-hohlraum, static-wall hohlraum, and Z-pinch-driven hohlraum concepts. Each has different potential strengths and concerns. In this paper, the authors report on the first experiments with the Z-pinch-driven hohlraum (ZPDH) concept. A high-yield ICF capsule design for this concept appears feasible, when driven by z-pinches from a 60 MA-class driver. Initial experiments characterize the behavior of the spoke array on Z-pinch performance and x-ray transmission, and the uniformity of radiation flux incident on a foam capsule in the secondary, for a single-sided drive. Measurements of x-ray wall re-emission power and spectrum, radiation temperatures, spoke-plasma location, and drive uniformity will be presented and compared with 0-D energetics, 2-D Lasnex rad-hydro, and 3-D radiosity calculations of energy transport and drive uniformity

  15. Development of a Z-pinch-driven ICF hohlraum concept on Z

    Energy Technology Data Exchange (ETDEWEB)

    Cuneo, M E; Porter, Jr, J L; Vesey, R A [and others

    1999-07-01

    Recent development of high power z-pinches (> 150 MW) on the Z driver has permitted the study of high-temperature, radiation-driven hohlraums. Three complementary, Z-pinch source-hohlraum-ICF capsule configurations are being developed to harness the x-ray output of these Z-pinch's. These are the dynamic-hohlraum, static-wall hohlraum, and Z-pinch-driven hohlraum concepts. Each has different potential strengths and concerns. In this paper, the authors report on the first experiments with the Z-pinch-driven hohlraum (ZPDH) concept. A high-yield ICF capsule design for this concept appears feasible, when driven by z-pinches from a 60 MA-class driver. Initial experiments characterize the behavior of the spoke array on Z-pinch performance and x-ray transmission, and the uniformity of radiation flux incident on a foam capsule in the secondary, for a single-sided drive. Measurements of x-ray wall re-emission power and spectrum, radiation temperatures, spoke-plasma location, and drive uniformity will be presented and compared with 0-D energetics, 2-D Lasnex rad-hydro, and 3-D radiosity calculations of energy transport and drive uniformity.

  16. Observation of hohlraum-wall motion with spectrally selective x-ray imaging at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Izumi, N., E-mail: izumi2@llnl.gov; Meezan, N. B.; Divol, L.; Hall, G. N.; Barrios, M. A.; Jones, O.; Landen, O. L.; Kroll, J. J.; Vonhof, S. A.; Nikroo, A.; Bailey, C. G.; Hardy, C. M.; Ehrlich, R. B.; Town, R. P. J.; Bradley, D. K.; Hinkel, D. E.; Moody, J. D. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Jaquez, J. [General Atomics, San Diego, California 9212 (United States)

    2016-11-15

    The high fuel capsule compression required for indirect drive inertial confinement fusion requires careful control of the X-ray drive symmetry throughout the laser pulse. When the outer cone beams strike the hohlraum wall, the plasma ablated off the hohlraum wall expands into the hohlraum and can alter both the outer and inner cone beam propagations and hence the X-ray drive symmetry especially at the final stage of the drive pulse. To quantitatively understand the wall motion, we developed a new experimental technique which visualizes the expansion and stagnation of the hohlraum wall plasma. Details of the experiment and the technique of spectrally selective x-ray imaging are discussed.

  17. Target design for high fusion yield with the double Z-pinch-driven hohlraum

    International Nuclear Information System (INIS)

    Vesey, R. A.; Herrmann, M. C.; Lemke, R. W.; Desjarlais, M. P.; Cuneo, M. E.; Stygar, W. A.; Bennett, G. R.; Campbell, R. B.; Christenson, P. J.; Mehlhorn, T. A.; Porter, J. L.; Slutz, S. A.

    2007-01-01

    A key demonstration on the path to inertial fusion energy is the achievement of high fusion yield (hundreds of MJ) and high target gain. Toward this goal, an indirect-drive high-yield inertial confinement fusion (ICF) target involving two Z-pinch x-ray sources heating a central secondary hohlraum is described by Hammer et al. [Phys. Plasmas 6, 2129 (1999)]. In subsequent research at Sandia National Laboratories, theoretical/computational models have been developed and an extensive series of validation experiments have been performed to study hohlraum energetics, capsule coupling, and capsule implosion symmetry for this system. These models have been used to design a high-yield Z-pinch-driven ICF target that incorporates the latest experience in capsule design, hohlraum symmetry control, and x-ray production by Z pinches. An x-ray energy output of 9 MJ per pinch, suitably pulse-shaped, is sufficient for this concept to drive 0.3-0.5 GJ capsules. For the first time, integrated two-dimensional (2D) hohlraum/capsule radiation-hydrodynamics simulations have demonstrated adequate hohlraum coupling, time-dependent radiation symmetry control, and the successful implosion, ignition, and burn of a high-yield capsule in the double Z-pinch hohlraum. An important new feature of this target design is mode-selective symmetry control: the use of burn-through shields offset from the capsule that selectively tune certain low-order asymmetry modes (P 2 ,P 4 ) without significantly perturbing higher-order modes and without a significant energy penalty. This paper will describe the capsule and hohlraum design that have produced 0.4-0.5 GJ yields in 2D simulations, provide a preliminary estimate of the Z-pinch load and accelerator requirements necessary to drive the system, and suggest future directions for target design work

  18. 3D Simulations of the ``Keyhole'' Hohlraum for Shock Timing on NIF

    Science.gov (United States)

    Robey, H. F.; Marinak, M. M.; Munro, D. H.; Jones, O. S.

    2007-11-01

    Ignition implosions planned for the National Ignition Facility (NIF) require a pulse shape with a carefully designed series of steps, which launch a series of shocks through the ablator and DT fuel. The relative timing of these shocks must be tuned to better than +/- 100ps to maintain the DT fuel on a sufficiently low adiabat. To meet these requirements, pre-ignition tuning experiments using a modified hohlraum geometry are being planned. This modified geometry, known as the ``keyhole'' hohlraum, adds a re-entrant gold cone, which passes through the hohlraum and capsule walls, to provide an optical line-of-sight to directly measure the shocks as they break out of the ablator. In order to assess the surrogacy of this modified geometry, 3D simulations using HYDRA [1] have been performed. The drive conditions and the resulting effect on shock timing in the keyhole hohlraum will be compared with the corresponding results for the standard ignition hohlraum. [1] M.M. Marinak, et al., Phys. Plasmas 8, 2275 (2001).

  19. Gas-filled Rugby hohlraum energetics and implosions experiments on OMEGA

    Science.gov (United States)

    Casner, Alexis; Philippe, F.; Tassin, V.; Seytor, P.; Monteil, M. C.; Villette, B.; Reverdin, C.

    2010-11-01

    Recent experiments [1,2] have validated the x-ray drive enhancement provided by rugby-shaped hohlraums over cylinders in the indirect drive (ID) approach to inertial confinement fusion (ICF). This class of hohlraum is the baseline design for the Laser Mégajoule program, is also applicable to the National Ignition Facility and could therefore benefit ID Inertial Fusion Energy studies. We have carried out a serie of energetics and implosions experiments with OMEGA ``scale 1'' rugby hohlraums [1,2]. For empty hohlraums these experiments provide complementary measurements of backscattered light along 42 cone, as well as detailed drive history. In the case of gas-filled rugby hohlraums we have also study implosion performance (symmetry, yield, bangtime, hotspot spectra...) using a high contrast shaped pulse leading to a different implosion regime and for a range of capsule convergence ratios. These results will be compared with FCI2 hydrocodes calculations and future experimental campaigns will be suggested. [4pt] [1] F. Philippe et al., Phys. Rev. Lett. 104, 035004 (2010). [0pt] [2] H. Robey et al., Phys. Plasnas 17, 056313 (2010).

  20. Computational modeling of z-pinch-driven hohlraum experiments on Z

    International Nuclear Information System (INIS)

    Vesey, R.A.; Porter, J.L. Jr.; Cuneo, M.E.

    1999-01-01

    The high-yield inertial confinement fusion concept based on a double-ended z-pinch driven hohlraum tolerates the degree of spatial inhomogeneity present in z-pinch plasma radiation sources by utilizing a relatively large hohlraum wall surface to provide spatial smoothing of the radiation delivered to the fusion capsule. The z-pinch radiation sources are separated from the capsule by radial spoke arrays. Key physics issues for this concept are the behavior of the spoke array (effect on the z-pinch performance, x-ray transmission) and the uniformity of the radiation flux incident on the surface of the capsule. Experiments are underway on the Z accelerator at Sandia National laboratories to gain understanding of these issues in a single-sided drive geometry. These experiments seek to measure the radiation coupling among the z-pinch, source hohlraum, and secondary hohlraum, as well as the uniformity of the radiation flux striking a foam witness ball diagnostic positioned in the secondary hohlraum. This paper will present the results of computational modeling of various aspects of these experiments

  1. 0-d energetics scaling models for Z-pinch-driven hohlraums

    International Nuclear Information System (INIS)

    CUNEO, MICHAEL E.; VESEY, ROGER A.; HAMMER, J.H.; PORTER, JOHN L.

    2000-01-01

    Wire array Z-pinches on the Z accelerator provide the most intense laboratory source of soft x-rays in the world. The unique combination of a highly-Planckian radiation source with high x-ray production efficiency (15% wall plug), large x-ray powers and energies ( >150 TW, ge1 MJ in 7 ns), large characteristic hohlraum volumes (0.5 to >10 cm 3 ), and long pulse-lengths (5 to 20 ns) may make Z-pinches a good match to the requirements for driving high-yield scale ICF capsules with adequate radiation symmetry and margin. The Z-pinch driven hohlraum approach of Hammer and Porter [Phys.Plasmas, 6, 2129(1999)] may provide a conservative and robust solution to the requirements for high yield, and is currently being studied on the Z accelerator. This paper describes a multiple region, 0-d hohlraum energetic model for Z-pinch driven hohlraums in four configurations. The authors observe consistency between the models and the measured x-ray powers and hohlraum wall temperatures to within ±20% in flux, for the four configurations

  2. Laser-generated magnetic fields in quasi-hohlraum geometries

    Science.gov (United States)

    Pollock, Bradley; Turnbull, David; Ross, Steven; Hazi, Andrew; Ralph, Joseph; Lepape, Sebastian; Froula, Dustin; Haberberger, Dan; Moody, John

    2014-10-01

    Laser-generated magnetic fields of 10--40 T have been produced with 100--4000 J laser drives at Omega EP and Titan. The fields are generated using the technique described by Daido et al. [Phys. Rev. Lett. 56, 846 (1986)], which works by directing a laser through a hole in one plate to strike a second plate. Hot electrons generated in the laser-produced plasma on the second plate collect on the first plate. A strap connects the two plates allowing a current of 10 s of kA to flow and generate a solenoidal magnetic field. The magnetic field is characterized using Faraday rotation, b-dot probes, and proton radiography. Further experiments to study the effect of the magnetic field on hohlraum performance are currently scheduled for Omega. This work was performed under the auspices of the United States Department of Energy by the Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA-27344.

  3. Characterizing high energy spectra of NIF ignition Hohlraums using a differentially filtered high energy multipinhole x-ray imager.

    Science.gov (United States)

    Park, Hye-Sook; Dewald, E D; Glenzer, S; Kalantar, D H; Kilkenny, J D; MacGowan, B J; Maddox, B R; Milovich, J L; Prasad, R R; Remington, B A; Robey, H F; Thomas, C A

    2010-10-01

    Understanding hot electron distributions generated inside Hohlraums is important to the national ignition campaign for controlling implosion symmetry and sources of preheat. While direct imaging of hot electrons is difficult, their spatial distribution and spectrum can be deduced by detecting high energy x-rays generated as they interact with target materials. We used an array of 18 pinholes with four independent filter combinations to image entire Hohlraums with a magnification of 0.87× during the Hohlraum energetics campaign on NIF. Comparing our results with Hohlraum simulations indicates that the characteristic 10-40 keV hot electrons are mainly generated from backscattered laser-plasma interactions rather than from Hohlraum hydrodynamics.

  4. Radiation transport and energetics of laser-driven half-hohlraums at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Moore, A. S., E-mail: alastair.moore@physics.org; Graham, P.; Comley, A. J.; Foster, J. [Directorate Science and Technology, AWE Aldermaston, Reading RG7 4PR (United Kingdom); Cooper, A. B. R.; Schneider, M. B.; MacLaren, S.; Lu, K.; Seugling, R.; Satcher, J.; Klingmann, J.; Marrs, R.; May, M.; Widmann, K.; Glendinning, G.; Castor, J.; Sain, J.; Baker, K.; Hsing, W. W.; Young, B. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808 (United States); and others

    2014-06-15

    Experiments that characterize and develop a high energy-density half-hohlraum platform for use in benchmarking radiation hydrodynamics models have been conducted at the National Ignition Facility (NIF). Results from the experiments are used to quantitatively compare with simulations of the radiation transported through an evolving plasma density structure, colloquially known as an N-wave. A half-hohlraum is heated by 80 NIF beams to a temperature of 240 eV. This creates a subsonic diffusive Marshak wave, which propagates into a high atomic number Ta{sub 2}O{sub 5} aerogel. The subsequent radiation transport through the aerogel and through slots cut into the aerogel layer is investigated. We describe a set of experiments that test the hohlraum performance and report on a range of x-ray measurements that absolutely quantify the energetics and radiation partition inside the target.

  5. Radiation transport and energetics of laser-driven half-hohlraums at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Moore, A. S. [Directorate Science and Technology, AWE Aldermaston, Reading (United Kingdom); Cooper, A. B.R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Schneider, M. B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); MacLaren, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Graham, P. [Directorate Science and Technology, AWE Aldermaston, Reading (United Kingdom); Lu, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Seugling, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Satcher, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Klingmann, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Comley, A. J. [Directorate Science and Technology, AWE Aldermaston, Reading (United Kingdom); Marrs, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); May, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Widmann, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Glendinning, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Castor, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sain, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Back, C. A. [General Atomics, San Diego, CA (United States); Hund, J. [General Atomics, San Diego, CA (United States); Baker, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hsing, W. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Foster, J. [Directorate Science and Technology, AWE Aldermaston, Reading (United Kingdom); Young, B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Young, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-06-01

    Experiments that characterize and develop a high energy-density half-hohlraum platform for use in bench-marking radiation hydrodynamics models have been conducted at the National Ignition Facility (NIF). Results from the experiments are used to quantitatively compare with simulations of the radiation transported through an evolving plasma density structure, colloquially known as an N-wave. A half-hohlraum is heated by 80 NIF beams to a temperature of 240 eV. This creates a subsonic di usive Marshak wave which propagates into a high atomic number Ta2O5 aerogel. The subsequent radiation transport through the aerogel and through slots cut into the aerogel layer is investigated. We describe a set of experiments that test the hohlraum performance and report on a range

  6. High-density carbon ablator ignition path with low-density gas-filled rugby hohlraum

    International Nuclear Information System (INIS)

    Amendt, Peter; Ho, Darwin D.; Jones, Ogden S.

    2015-01-01

    A recent low gas-fill density (0.6 mg/cc 4 He) cylindrical hohlraum experiment on the National Ignition Facility has shown high laser-coupling efficiency (>96%), reduced phenomenological laser drive corrections, and improved high-density carbon capsule implosion symmetry [Jones et al., Bull. Am. Phys. Soc. 59(15), 66 (2014)]. In this Letter, an ignition design using a large rugby-shaped hohlraum [Amendt et al., Phys. Plasmas 21, 112703 (2014)] for high energetics efficiency and symmetry control with the same low gas-fill density (0.6 mg/cc 4 He) is developed as a potentially robust platform for demonstrating thermonuclear burn. The companion high-density carbon capsule for this hohlraum design is driven by an adiabat-shaped [Betti et al., Phys. Plasmas 9, 2277 (2002)] 4-shock drive profile for robust high gain (>10) 1-D ignition performance and large margin to 2-D perturbation growth

  7. High-density carbon ablator ignition path with low-density gas-filled rugby hohlraum

    Science.gov (United States)

    Amendt, Peter; Ho, Darwin D.; Jones, Ogden S.

    2015-04-01

    A recent low gas-fill density (0.6 mg/cc 4He) cylindrical hohlraum experiment on the National Ignition Facility has shown high laser-coupling efficiency (>96%), reduced phenomenological laser drive corrections, and improved high-density carbon capsule implosion symmetry [Jones et al., Bull. Am. Phys. Soc. 59(15), 66 (2014)]. In this Letter, an ignition design using a large rugby-shaped hohlraum [Amendt et al., Phys. Plasmas 21, 112703 (2014)] for high energetics efficiency and symmetry control with the same low gas-fill density (0.6 mg/cc 4He) is developed as a potentially robust platform for demonstrating thermonuclear burn. The companion high-density carbon capsule for this hohlraum design is driven by an adiabat-shaped [Betti et al., Phys. Plasmas 9, 2277 (2002)] 4-shock drive profile for robust high gain (>10) 1-D ignition performance and large margin to 2-D perturbation growth.

  8. High-density carbon ablator ignition path with low-density gas-filled rugby hohlraum

    Energy Technology Data Exchange (ETDEWEB)

    Amendt, Peter; Ho, Darwin D.; Jones, Ogden S. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

    2015-04-15

    A recent low gas-fill density (0.6 mg/cc {sup 4}He) cylindrical hohlraum experiment on the National Ignition Facility has shown high laser-coupling efficiency (>96%), reduced phenomenological laser drive corrections, and improved high-density carbon capsule implosion symmetry [Jones et al., Bull. Am. Phys. Soc. 59(15), 66 (2014)]. In this Letter, an ignition design using a large rugby-shaped hohlraum [Amendt et al., Phys. Plasmas 21, 112703 (2014)] for high energetics efficiency and symmetry control with the same low gas-fill density (0.6 mg/cc {sup 4}He) is developed as a potentially robust platform for demonstrating thermonuclear burn. The companion high-density carbon capsule for this hohlraum design is driven by an adiabat-shaped [Betti et al., Phys. Plasmas 9, 2277 (2002)] 4-shock drive profile for robust high gain (>10) 1-D ignition performance and large margin to 2-D perturbation growth.

  9. High Performance Capsule Implosions on the Omega Laser Facility with Rugby Hohlraums

    Science.gov (United States)

    Robey, Harry F.

    2009-11-01

    Rugby-shaped hohlraums have been proposed as a method for x-ray drive enhancement for indirectly-driven capsule implosions [1]. This concept has recently been tested in a series of shots on the OMEGA laser facility at the Laboratory for Laser Energetics at the University of Rochester. In this talk, experimental results are presented comparing the performance of D2-filled capsules between standard cylindrical Au hohlraums and rugby-shaped hohlraums. Not only did the rugby hohlraums demonstrate 18% more x-ray drive energy as compared with the cylinders, but the high-performance design of these implosions (both cylinder and rugby) also provided 20X more DD neutrons than any previous indirectly-driven campaign on Omega (and 3X more than ever achieved on Nova implosions driven with nearly twice the laser energy). This increase in performance enables, for the first time, a measurement of the neutron burn history of an indirectly-driven implosion. Previous DD neutron yields had been too low to register this key measurement of capsule performance and the effects of dynamic mix. A wealth of additional data on the fuel areal density from the suite of charged particle diagnostics was obtained on a subset of the shots that used D^3He rather than D2 fuel. Comparisons of the experimental results with numerical simulations are shown to be in excellent agreement. The design techniques employed in this campaign, e.g., smaller NIF-like laser entrance holes and hohlraum case-to-capsule ratios, provide added confidence in the pursuit of ignition on the National Ignition Facility. [4pt] [1] P. Amendt, C. Cerjan, D. E. Hinkel, J. L. Milovich, H.-S. Park, and H. F. Robey, ``Rugby-like hohlraum experimental designs for demonstrating x-ray drive enhancement'', Phys. Plasmas 15, 012702 (2008).

  10. Full aperture backscatter signal analysis of laser with hohlraum on Shenguang II laser facility

    International Nuclear Information System (INIS)

    Jiao Chunye; Wang Feng; Liu Shenye; Jiang Xiaohua; Li Sanwei; Liu Yonggang; Yang Jiamin; Gu Yuqiu; Wang Chuanke

    2010-01-01

    Full aperture backscatter system and experimental measurement of hohlraum with 351 nm wavelength laser on Shenguang II laser facility is reported. FABS optical path has been analyzed and the backscattering light completely entered FABS collecting optical path. FABS existed the background light when the eight beams symmetrically acted on hohlraum. The background light is composed of 526.5 nm and 1053 nm wavelength remains while the 1053 nm wavelength changes into 351 nm wavelength, according to records of laser sensitive paper and optical filter. The background light accounts for 15% of FABS energy from experimental measurement result. (authors)

  11. X-ray conversion efficiency of high-Z hohlraum wall materials for indirect drive ignition

    International Nuclear Information System (INIS)

    Dewald, E. L.; Rosen, M.; Glenzer, S. H.; Suter, L. J.; Neumayer, P.; Landen, O. L.; Girard, F.; Jadaud, J. P.; Wagon, F.; Huser, G.; Schein, J.; Constantin, C.

    2008-01-01

    The conversion efficiency of 351 nm laser light to soft x rays (0.1-5 keV) was measured for Au, U, and high Z mixture ''cocktails'' used as hohlraum wall materials in indirect drive fusion experiments. For the spherical targets in a direct drive geometry, flattop laser pulses and laser smoothing with phase plates are employed to achieve constant and uniform laser intensities of 10 14 and 10 15 W/cm 2 over the target surface that are relevant for the future ignition experiments at the National Ignition Facility [G. H. Miller, E. I. Moses, and C. R. Wuest, Nucl. Fusion 44, 228 (2004)]. The absolute time and spectrally resolved radiation flux is measured with a multichannel soft x-ray power diagnostic. The conversion efficiency is then calculated by dividing the measured x-ray power by the incident laser power from which the measured laser backscattering losses are subtracted. After ∼0.5 ns, the time resolved x-ray conversion efficiency reaches a slowly increasing plateau of 95% at 10 14 W/cm 2 laser intensity and of 80% at 10 15 W/cm 2 . The M-band flux (2-5 keV) is negligible at 10 14 W/cm 2 reaching ∼1% of the total x-ray flux for all target materials. In contrast, the M-band flux is significant and depends on the target material at 10 15 W/cm 2 laser intensity, reaching values between 10% of the total flux for U and 27% for Au. LASNEX simulations [G. B. Zimmerman and W. L. Kruer, Comm. Plasma Phys. Contr. Fusion 2, 51 (1975)] show good agreement in conversion efficiency and radiated spectra with data when using XSN atomic physics model and a flux limiter of 0.15, but they underestimate the generated M-band flux.

  12. Indirect drive ablative Rayleigh-Taylor experiments with rugby hohlraums on OMEGA

    International Nuclear Information System (INIS)

    Casner, A.; Galmiche, D.; Huser, G.; Jadaud, J.-P.; Liberatore, S.; Vandenboomgaerde, M.

    2009-01-01

    Results of ablative Rayleigh-Taylor instability growth experiments performed in indirect drive on the OMEGA laser facility [T. R. Boehly, D. L. Brown, S. Craxton et al., Opt. Commun. 133, 495 (1997)] are reported. These experiments aim at benchmarking hydrocodes simulations and ablator instabilities growth in conditions relevant to ignition in the framework of the Laser MegaJoule [C. Cavailler, Plasma Phys. Controlled Fusion 47, 389 (2005)]. The modulated samples under study were made of germanium-doped plastic (CHGe), which is the nominal ablator for future ignition experiments. The incident x-ray drive was provided using rugby-shaped hohlraums [M. Vandenboomgaerde, J. Bastian, A. Casner et al., Phys. Rev. Lett. 99, 065004 (2007)] and was characterized by means of absolute time-resolved soft x-ray power measurements through a dedicated diagnostic hole, shock breakout data and one-dimensional and two-dimensional (2D) side-on radiographies. All these independent x-ray drive diagnostics lead to an actual on-foil flux that is about 50% smaller than laser-entrance-hole measurements. The experimentally inferred flux is used to simulate experimental optical depths obtained from face-on radiographies for an extensive set of initial conditions: front-side single-mode (wavelength λ=35, 50, and 70 μm) and two-mode perturbations (wavelength λ=35 and 70 μm, in phase or in opposite phase). Three-dimensional pattern growth is also compared with the 2D case. Finally the case of the feedthrough mechanism is addressed with rear-side modulated foils.

  13. Indirect drive ablative Rayleigh-Taylor experiments with rugby hohlraums on OMEGA

    Science.gov (United States)

    Casner, A.; Galmiche, D.; Huser, G.; Jadaud, J.-P.; Liberatore, S.; Vandenboomgaerde, M.

    2009-09-01

    Results of ablative Rayleigh-Taylor instability growth experiments performed in indirect drive on the OMEGA laser facility [T. R. Boehly, D. L. Brown, S. Craxton et al., Opt. Commun. 133, 495 (1997)] are reported. These experiments aim at benchmarking hydrocodes simulations and ablator instabilities growth in conditions relevant to ignition in the framework of the Laser MégaJoule [C. Cavailler, Plasma Phys. Controlled Fusion 47, 389 (2005)]. The modulated samples under study were made of germanium-doped plastic (CHGe), which is the nominal ablator for future ignition experiments. The incident x-ray drive was provided using rugby-shaped hohlraums [M. Vandenboomgaerde, J. Bastian, A. Casner et al., Phys. Rev. Lett. 99, 065004 (2007)] and was characterized by means of absolute time-resolved soft x-ray power measurements through a dedicated diagnostic hole, shock breakout data and one-dimensional and two-dimensional (2D) side-on radiographies. All these independent x-ray drive diagnostics lead to an actual on-foil flux that is about 50% smaller than laser-entrance-hole measurements. The experimentally inferred flux is used to simulate experimental optical depths obtained from face-on radiographies for an extensive set of initial conditions: front-side single-mode (wavelength λ =35, 50, and 70 μm) and two-mode perturbations (wavelength λ =35 and 70 μm, in phase or in opposite phase). Three-dimensional pattern growth is also compared with the 2D case. Finally the case of the feedthrough mechanism is addressed with rear-side modulated foils.

  14. X-ray Conversion Efficiency of high-Z hohlraum wall materials for indirect drive ignition

    International Nuclear Information System (INIS)

    Dewald, E.; Rosen, M.; Glenzer, S.H.; Suter, L.J.; Girard, F.; Jadaud, J.P.; Schein, J.; Constantin, C.G.; Neumayer, P.; Landen, O.

    2008-01-01

    We measure the conversion efficiency of 351 nm laser light to soft x-rays (0.1-5 keV) for Au, U and high Z mixtures 'cocktails' used for hohlraum wall materials in indirect drive ICF. We use spherical targets in a direct drive geometry, flattop laser pulses and laser smoothing with phase plates to achieve constant and uniform laser intensities of 10 14 and 10 15 W/cm 2 over the target surface that are relevant for the future ignition experiments on NIF. The absolute time and spectrally-resolved radiation flux is measured with a multichannel soft x-ray power diagnostic. The conversion efficiency is then calculated by dividing the measured x-ray power by the incident laser power from which the measured laser backscattering losses is subtracted. After ∼0.5 ns, the time resolved x-ray conversion efficiency reaches a slowly increasing plateau of 95% at 10 14 W/cm 2 laser intensity and of 80% at 10 15 W/cm 2 . The M-band flux (2-5 keV) is negligible at 10 14 W/cm 2 reaching ∼1% of the total x-ray flux for all target materials. In contrast, the M-band flux is significant and depends on the target material at 10 15 W/cm 2 laser intensity, reaching values between 10% of the total flux for U and 27% for Au. Our LASNEX simulations show good agreement in conversion efficiency and radiated spectra with data when using XSN atomic physics model and a flux limiter of 0.15, but they underestimate the generated M-band flux

  15. Mitigating the impact of hohlraum asymmetries in National Ignition Facility implosions using capsule shims

    Energy Technology Data Exchange (ETDEWEB)

    Clark, D. S.; Weber, C. R.; Smalyuk, V. A.; Robey, H. F.; Kritcher, A. L.; Milovich, J. L.; Salmonson, J. D. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)

    2016-07-15

    Current indirect drive implosion experiments on the National Ignition Facility (NIF) [Moses et al., Phys. Plasmas 16, 041006 (2009)] are believed to be strongly impacted by long wavelength perturbations driven by asymmetries in the hohlraum x-ray flux. To address this perturbation source, active efforts are underway to develop modified hohlraum designs with reduced asymmetry imprint. An alternative strategy, however, is to modify the capsule design to be more resilient to a given amount of hohlraum asymmetry. In particular, the capsule may be deliberately misshaped, or “shimmed,” so as to counteract the expected asymmetries from the hohlraum. Here, the efficacy of capsule shimming to correct the asymmetries in two recent NIF implosion experiments is assessed using two-dimensional radiation hydrodynamics simulations. Despite the highly time-dependent character of the asymmetries and the high convergence ratios of these implosions, simulations suggest that shims could be highly effective at counteracting current asymmetries and result in factors of a few enhancements in neutron yields. For higher compression designs, the yield improvement could be even greater.

  16. Numerical simulations of radiation hydrodynamics and modeling of high temperature hohlraum cavities

    International Nuclear Information System (INIS)

    Gupta, N.K.; Godwal, B.K.

    2003-10-01

    A summary of our efforts towards the validation of radiation hydrodynamics and opacity models are presented. Effects of various parameters on the radiation temperature inside an inertial confinement fusion (ICF) hohlraum, the effects of non-local thermodynamic equilibrium conditions on emission and absorption, and the hydrodynamics of aluminium and gold foils driven by radiation are studied. LTE and non-LTE predictions for emitted radiation are compared with the experimental results and it is seen that non-LTE simulations show a marked improvement over LTE results. It is shown that the mixing of two high Z materials can lead to an enhancement in the Rosseland mean. An experimental study of soft x-ray emission from laser-irradiated Au-Cu mix-Z targets confirmed these predictions. It is seen that only multi group non-LTE radiation transport is able to explain experimentally observed features in the conversion efficiency of laser light to x-rays. One group radiation transport under predicts the radiation temperature. It is shown that erroneous results can be obtained if the space mesh in the hohlraum wall is not fine enough. Hydrodynamics of a wedge shaped aluminium foil driven by the hohlraum radiation is also presented and results are compared with NOVA laser experiments. Laser driven shock wave EOS and gold hohlraum experiments carried out at CAT are analyzed and they confirmed our theoretical estimates. (author)

  17. New compact hohlraum configuration research at the 1.7 MA Z-pinch generator

    Energy Technology Data Exchange (ETDEWEB)

    Kantsyrev, V. L., E-mail: victor@unr.edu; Shrestha, I. K.; Esaulov, A. A.; Safronova, A. S.; Shlyaptseva, V. V.; Osborne, G. C.; Astanovitsky, A. L.; Weller, M. E.; Stafford, A.; Schultz, K. A.; Cooper, M. C. [Physics Department, University of Nevada, Reno, NV 89557 (United States); Chuvatin, A. S. [Laboratorie de Physique des Plasmas, Ecole Polytechnique, 91128 Palaiseau (France); Rudakov, L. I. [Icarus Research Inc., P.O. Box 30780, Bethesda, MD 20824-0780 (United States); Velikovich, A. L. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Cuneo, M. E.; Jones, B.; Vesey, R. A. [Sandia National Laboratories, Albuquerque, NM 87110 (United States)

    2014-12-15

    A new compact Z-pinch x-ray hohlraum design with parallel-driven x-ray sources was experimentally demonstrated in a full configuration with a central target and tailored shine shields (to provide a symmetric temperature distribution on the target) at the 1.7 MA Zebra generator. This presentation reports on the joint success of two independent lines of research. One of these was the development of new sources – planar wire arrays (PWAs). PWAs turned out to be a prolific radiator. Another success was the drastic improvement in energy efficiency of pulsed-power systems, such as the Load Current Multiplier (LCM). The Zebra/LCM generator almost doubled the plasma load current to 1.7 MA. The two above-mentioned innovative approaches were used in combination to produce a new compact hohlraum design for ICF, as jointly proposed by SNL and UNR. Good agreement between simulated and measured radiation temperature of the central target is shown. Experimental comparison of PWAs with planar foil liners (PFL) - another viable alternative to wire array loads at multi-MA generators show promising data. Results of research at the University of Nevada Reno allowed for the study of hohlraum coupling physics at University-scale generators. The advantages of new hohlraum design applications for multi-MA facilities with W or Au double PWAs or PFL x-ray sources are discussed.

  18. The LMJ project - status of our knowledge in hohlraum energetics physics: production and control of the radiation flux

    International Nuclear Information System (INIS)

    Dattolo, E.

    2001-09-01

    CEA-DAM in France is working on Inertial controlled Fusion (ICF) since the beginning of nineties. In an indirect drive scheme, the laser light is converted in X-ray in a hohlraum made with an high-Z material. Part of this radiation flux is absorbed by a micro-balloon filled with DT, placed in the center of the hohlraum, and generates its implosion, ignition and burn. This paper gives the status of our knowledge and studies for production and control of the radiation flux in the hohlraum, in the perspective of the Laser MegaJoule (LMJ). (authors)

  19. Experimental room temperature hohlraum performance study on the National Ignition Facility

    Science.gov (United States)

    Ralph, J. E.; Strozzi, D.; Ma, T.; Moody, J. D.; Hinkel, D. E.; Callahan, D. A.; MacGowan, B. J.; Michel, P.; Kline, J. L.; Glenzer, S. H.; Albert, F.; Benedetti, L. R.; Divol, L.; MacKinnon, A. J.; Pak, A.; Rygg, J. R.; Schneider, M. B.; Town, R. P. J.; Widmann, K.; Hsing, W.; Edwards, M. J.

    2016-12-01

    Room temperature or "warm" (273 K) indirect drive hohlraum experiments have been conducted on the National Ignition Facility with laser energies up to 1.26 MJ and compared to similar cryogenic or "cryo" (˜20 K) experiments. Warm experiments use neopentane (C5H12) as the low pressure hohlraum fill gas instead of helium, and propane (C3H8) to replace the cryogenic DT or DHe3 capsule fill. The increased average Z of the hohlraum fill leads to increased inverse bremsstrahlung absorption and an overall hotter hohlraum plasma in simulations. The cross beam energy transfer (CBET) from outer laser beams (pointed toward the laser entrance hole) to inner beams (pointed at the equator) was inferred indirectly from measurements of Stimulated Raman Scattering (SRS). These experiments show that a similar hot spot self-emission shape can be produced with less CBET in warm hohlraums. The measured inner cone SRS reflectivity (as a fraction of incident power neglecting CBET) is ˜2.5 × less in warm than cryo shots with similar hot spot shapes, due to a less need for CBET. The measured outer-beam stimulated the Brillouin scattering power that was higher in the warm shots, leading to a ceiling on power to avoid the optics damage. These measurements also show that the CBET induced by the flow where the beams cross can be effectively mitigated by a 1.5 Å wavelength shift between the inner and outer beams. A smaller scale direct comparison indicates that warm shots give a more prolate implosion than cryo shots with the same wavelength shift and pulse shape. Finally, the peak radiation temperature was found to be between 5 and 7 eV higher in the warm than the corresponding cryo experiments after accounting for differences in backscatter.

  20. Initial Computational Study of a New Multi-Hole Hohlraum (the "Midraum")

    Energy Technology Data Exchange (ETDEWEB)

    Tabak, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Jones, O. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-11-02

    Existing cylindrical hohlraums with two oppositely positioned laser entrance holes (LEHs) have multiple constraints. Their goal is to produce radiation sources distributed over the sky, as visible from the spherical implosion capsule, with most of the deposition near the zeroes of the fourth Legendre polynomial in cosine of the polar angle. This requires some of the laser light to propagate across the hohlraum to positions near the hohlraum symmetry plane. The ratio of case spherical radius to capsule spherical radius should exceed 3 so that the light doesn’t pass through over-dense ablator plasma. Radiation transport can smooth higher radiation modes. For capsules that demand long pulse lengths, hohlraum walls can blow in and change the position where light is absorbed. This changes the radiation symmetry in a time dependent fashion. This affects both P2 and P4. This wall motion can be reduced by introducing fill gas into the hohlraum. The gas provides back pressure and tamps the wall motion. Adding the fill gas comes at some cost. It leads to increased absorption of laser light along the path. The fill gas adds heat capacity to the system, ultimately requiring more laser energy to meet the radiation flux goals, both in total and particularly in the amount of radiation coming from the vicinity of the capsule waist. Given the existing beam pointing at NIF energy from the outer beams must be transferred into the inner beams. Cross beam energy transport (CBET) is accomplished via a plasma instability. This transfer is not perfectly predictable. In addition, the higher intensity required to make up for the losses along the long path can lead to stimulated backscatter as well as the generation of suprathermal electrons. The inner beams will pass through the plasma ablated from the capsule toward the end of the pulse. Heating this plasma acts as another parasitic loss. In addition, the light passing through the turbulent blow-off can be refracted in unpredictable

  1. High performance capsule implosions on the OMEGA Laser facility with rugby hohlraums

    International Nuclear Information System (INIS)

    Robey, H. F.; Amendt, P.; Park, H.-S.; Town, R. P. J.; Milovich, J. L.; Doeppner, T.; Hinkel, D. E.; Wallace, R.; Sorce, C.; Strozzi, D. J.; Philippe, F.; Casner, A.; Caillaud, T.; Landoas, O.; Liberatore, S.; Monteil, M.-C.; Seguin, F.; Rosenberg, M.; Li, C. K.; Petrasso, R.

    2010-01-01

    Rugby-shaped hohlraums have been proposed as a method for x-ray drive enhancement for indirectly driven capsule implosions. This concept has recently been tested in a series of shots on the OMEGA laser facility [T. R. Boehly, D. L. Brown, R. S. Craxton et al., Opt. Commun. 133, 495 (1997)]. In this paper, experimental results are presented comparing the performance of D 2 -filled capsules between standard cylindrical Au hohlraums and rugby-shaped hohlraums. The rugby hohlraums demonstrated 18% more x-ray drive energy as compared with the cylinders, and the high-performance design of these implosions (both cylinder and rugby) also provided ≅20x more deuterium (DD) neutrons than any previous indirectly driven campaign on OMEGA and ≅3x more than ever achieved on NOVA [E. M. Campbell, Laser Part. Beams 9, 209 (1991)] implosions driven with nearly twice the laser energy. This increase in performance enables, for the first time, a measurement of the neutron burn history and imaging of the neutron core shapes in an indirectly driven implosion. Previous DD neutron yields had been too low to register this key measurement of capsule performance and the effects of dynamic mix. A wealth of additional data on the fuel areal density from the suite of charged particle diagnostics was obtained on a subset of the shots that used D 3 He rather than D 2 fuel. Comparisons of the experimental results with numerical simulations are shown to be in very good agreement. The design techniques employed in this campaign, e.g., smaller laser entrance holes and hohlraum case-to-capsule ratios, provide added confidence in the pursuit of ignition on the National Ignition Facility [J. D. Lindl, P. Amendt, R. L. Berger et al., Phys. Plasmas 11, 339 (2004)].

  2. Hohlraum glint and laser pre-pulse detector for NIF experiments using velocity interferometer system for any reflector.

    Science.gov (United States)

    Moody, J D; Clancy, T J; Frieders, G; Celliers, P M; Ralph, J; Turnbull, D P

    2014-11-01

    Laser pre-pulse and early-time laser reflection from the hohlraum wall onto the capsule (termed "glint") can cause capsule imprint and unwanted early-time shocks on indirect drive implosion experiments. In a minor modification to the existing velocity interferometer system for any reflector diagnostic on NIF a fast-response vacuum photodiode was added to detect this light. The measurements show evidence of laser pre-pulse and possible light reflection off the hohlraum wall and onto the capsule.

  3. High-temperature dynamic hohlraums on the pulsed power driver Z

    International Nuclear Information System (INIS)

    Nash, T.J.; Derzon, M.S.; Chandler, G.A.; Leeper, R.; Fehl, D.; Lash, J.; Ruiz, C.; Cooper, G.; Seaman, J.F.; McGurn, J.; Lazier, S.; Torres, J.; Jobe, D.; Gilliland, T.; Hurst, M.; Mock, R.; Ryan, P.; Nielsen, D.; Armijo, J.; McKenney, J.; Hawn, R.; Hebron, D.; MacFarlane, J.J.; Petersen, D.; Bowers, R.; Matuska, W.; Ryutov, D.D.

    1999-01-01

    In the concept of the dynamic hohlraum an imploding Z pinch is optically thick to its own radiation. Radiation may be trapped inside the pinch to give a radiation temperature inside the pinch greater than that outside the pinch. The radiation is typically produced by colliding an outer Z-pinch liner onto an inner liner. The collision generates a strongly radiating shock, and the radiation is trapped by the outer liner. As the implosion continues after the collision, the radiation temperature may continue to increase due to ongoing PdV (pressure times change in volume) work done by the implosion. In principal, the radiation temperature may increase to the point at which the outer liner burns through, becomes optically thin, and no longer traps the radiation. One application of the dynamic hohlraum is to drive an ICF (inertial confinement fusion) pellet with the trapped radiation field. Members of the dynamic hohlraum team at Sandia National Labs have used the pulsed power driver Z (20 MA, 100 ns) to create a dynamic hohlraum with temperature linearly ramping from 100 to 180 eV over 5 ns. On this shot zp214 a nested tungsten wire array of 4 and 2 cm diam with masses of 2 and 1 mg imploded onto a 2.5 mg plastic annulus at 5 mm diam. The current return can on this shot was slotted. It is likely the radiation temperature may be increased to over 200 eV by stabilizing the pinch with a solid current return can. A current return can with nine slots imprints nine filaments onto the imploding pinch. This degrades the optical trapping and the quality of the liner collision. A 1.6 mm diam capsule situated inside this dynamic hohlraum of zp214 would see 15 kJ of radiation impinging on its surface before the pinch itself collapses to a 1.6 mm diam. Dynamic hohlraum shots including pellets were scheduled to take place on Z in September of 1998. copyright 1999 American Institute of Physics

  4. A systematic review of methodology applied during preclinical anesthetic neurotoxicity studies: important issues and lessons relevant to the design of future clinical research.

    Science.gov (United States)

    Disma, Nicola; Mondardini, Maria C; Terrando, Niccolò; Absalom, Anthony R; Bilotta, Federico

    2016-01-01

    Preclinical evidence suggests that anesthetic agents harm the developing brain thereby causing long-term neurocognitive impairments. It is not clear if these findings apply to humans, and retrospective epidemiological studies thus far have failed to show definitive evidence that anesthetic agents are harmful to the developing human brain. The aim of this systematic review was to summarize the preclinical studies published over the past decade, with a focus on methodological issues, to facilitate the comparison between different preclinical studies and inform better design of future trials. The literature search identified 941 articles related to the topic of neurotoxicity. As the primary aim of this systematic review was to compare methodologies applied in animal studies to inform future trials, we excluded a priori all articles focused on putative mechanism of neurotoxicity and the neuroprotective agents. Forty-seven preclinical studies were finally included in this review. Methods used in these studies were highly heterogeneous-animals were exposed to anesthetic agents at different developmental stages, in various doses and in various combinations with other drugs, and overall showed diverse toxicity profiles. Physiological monitoring and maintenance of physiological homeostasis was variable and the use of cognitive tests was generally limited to assessment of specific brain areas, with restricted translational relevance to humans. Comparison between studies is thus complicated by this heterogeneous methodology and the relevance of the combined body of literature to humans remains uncertain. Future preclinical studies should use better standardized methodologies to facilitate transferability of findings from preclinical into clinical science. © 2015 John Wiley & Sons Ltd.

  5. Z-pinch driven hohlraums design for the 100 nanoseconds current time scale

    International Nuclear Information System (INIS)

    Hamann, F.

    2003-12-01

    This work estimates Z-pinch driven hohlraums capabilities to obtain high temperatures (>200 eV). Simple models are proposed to calculate the performances offered by currents of 5 to 100 MA in 100 ns. The one dimensional physics of the Z-pinch at the length scale of its thickness and the hydrodynamics instabilities are studied. Then the enhancement of hohlraums performances with double nested Z-pinches or the use of an axial magnetic field is analysed. Z-pinch direct drive approach for inertial confinement fusion is finally considered. All the presented results are based on theoretical and 2D numerical approach and on the analysis of experimental results which were obtained on the american 'Z' generator. Annexes recall radiation MHD equations and check their validity for Z-pinch implosion. (author)

  6. Three-dimensional modeling of capsule implosions in OMEGA tetrahedral hohlraums

    International Nuclear Information System (INIS)

    Schnittman, J. D.; Craxton, R. S.

    2000-01-01

    Tetrahedral hohlraums have been proposed as a means for achieving the highly uniform implosions needed for ignition with inertial confinement fusion (ICF) [J. D. Schnittman and R. S. Craxton, Phys. Plasmas 3, 3786 (1996)]. Recent experiments on the OMEGA laser system have achieved good drive uniformity consistent with theoretical predictions [J. M. Wallace et al., Phys. Rev. Lett. 82, 3807 (1999)]. To better understand these experiments and future investigations of high-convergence ICF implosions, the three-dimensional (3-D) view-factor code BUTTERCUP has been expanded to model the time-dependent radiation transport in the hohlraum and the hydrodynamic implosion of the capsule. Additionally, a 3-D postprocessor has been written to simulate x-ray images of the imploded core. Despite BUTTERCUP's relative simplicity, its predictions for radiation drive temperatures, fusion yields, and core deformation show close agreement with experiment. (c) 2000 American Institute of Physics

  7. 2D simulations of hohlraum targets for laser-plasma experiments and ion stopping measurement in hot plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Basko, M.M. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany). ExtreMe Matter Institute EMMI; Maruhn, J.; Tauschwitz, Anna [Frankfurt Univ. (Germany); Novikov, V.G.; Grushin, A.S. [Keldysh Institute of Applied Mathematics, Moscow (Russian Federation)

    2011-12-15

    An attractive way to create uniform plasma states at high temperatures and densities is by using hohlraums - cavities with heavy-metal walls that are either directly or indirectly heated by intense laser pulses to x-ray temperatures of tens and hundreds electron volts. A sample material, whose plasma state is to be studied, can be placed inside such a hohlraum (usually in the form of a low-density foam) and uniformly heated to a high temperature. In this case a high-Z hohlraum enclosure serves a double purpose: it prevents the hot plasma from rapid disassembly due to hydrodynamic expansion and, at the same time, suppresses its rapid radiative cooling by providing high diffusive resistivity for X-rays. Of course, both the inertial and the thermal confinement of high-temperature plasmas can be achieved only for a limited period of time - on the order of nanoseconds for millimeter-scale hohlraums. Some time ago such hohlraum targets were proposed for measurements of the stopping power of hot dense plasmas for fast ions at GSI (Darmstadt). Theoretical modeling of hohlraum targets has always been a challenging task for computational physics because it should combine multidimensional hydrodynamic simulations with the solution of the spectral transfer equation for thermal radiation. In this work we report on our latest progress in this direction, namely, we present the results of 2D (two-dimensional) simulations with a newly developed radiation-hydrodynamics code RALEF-2D of two types of the hohlraum targets proposed for experiments on the PHELIX laser at GSI. The first configuration is a simple spherical hohlraum with gold walls and empty interior, which has two holes - one for laser beam entrance, and the other for diagnostics. The hohlraums of this type have already been used in several experimental sessions with the NHELIX and PHELIX lasers at GSI. The second type is a two-chamber cylindrical hohlraum with a characteristic {omega}-shaped cross-section of the enclosure

  8. 2-D simulation of hohlraum targets for HIDIF: gold vs. beryllium converters

    International Nuclear Information System (INIS)

    Honrubia, J.J.; Meyer-ter-Vehn, J.

    2000-01-01

    Two cylindrical hohlraum targets for heavy-ion-fusion are compared from the point of view of total ion-energy required to ignite a specified capsule. Target a, a simple bare gold cylindrical cavity behaves much more efficiently than Target b, the former one internally cladded with solid beryllium where convenient, to ensure ion energy conversion to X-rays mainly in this cladding. A discussion of the problem is provided. (authors)

  9. Demonstrated high performance of gas-filled rugby-shaped hohlraums on Omega

    Energy Technology Data Exchange (ETDEWEB)

    Philippe, F.; Villette, B. [CEA, DAM, DIF, F-91297 Arpajon (France); Michel, P. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Petrasso, R. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Stoeckl, C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Giraldez, E. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Tassin, V.; Depierreux, S.; Gauthier, P.; Masson-Laborde, P. E.; Monteil, M. C.; Seytor, P.; Lasinski, B.; Park, H. S.; Ross, J. S.; Amendt, P.; Döppner, T.; Hinkel, D. E.; Wallace, R.; Williams, E.; and others

    2014-07-15

    A direct experimental comparison of rugby-shaped and cylindrical shaped gas-filled hohlraums on the Omega laser facility demonstrates that higher coupling and minimal backscatter can be achieved in the rugby geometry, leading to significantly enhanced implosion performance. A nearly 50% increase of x-ray drive is associated with earlier bangtime and increase of neutron production. The observed drive enhancement from rugby geometry in this study is almost twice stronger than in previously published results.

  10. Planar hydrodynamic instability computations and experiments with rugby-shaped hohlraums at the Omega laser

    International Nuclear Information System (INIS)

    Vandenboomgaerde, M; Liberatore, S; Galmiche, D; Casner, A; Huser, G; Jadaud, J P; Villette, B

    2008-01-01

    Implosion of inertial confinement fusion (ICF) capsule is very sensitive to the growth of sphericity perturbations. The control of the feeding of such perturbations and their transport ('feedthrough') through the ablator is a key point to reach ignition. Since 2002, experiments have been designed and performed on the Omega laser facility in order to study these phenomena in planar geometry. A new 'rugby shaped' hohlraum was used. We present experimental results and comparisons with numerical simulations

  11. Planar hydrodynamic instability computations and experiments with rugby-shaped hohlraums at the Omega laser

    Energy Technology Data Exchange (ETDEWEB)

    Vandenboomgaerde, M; Liberatore, S; Galmiche, D; Casner, A; Huser, G; Jadaud, J P; Villette, B [Commissariat a l' Energie Atomique, CEA/DAM-Ile de France, BP 12, 91680 Bruyeres-Le-Chatel (France)

    2008-05-15

    Implosion of inertial confinement fusion (ICF) capsule is very sensitive to the growth of sphericity perturbations. The control of the feeding of such perturbations and their transport ('feedthrough') through the ablator is a key point to reach ignition. Since 2002, experiments have been designed and performed on the Omega laser facility in order to study these phenomena in planar geometry. A new 'rugby shaped' hohlraum was used. We present experimental results and comparisons with numerical simulations.

  12. Demonstrated high performance of gas-filled rugby-shaped hohlraums on Omega

    Science.gov (United States)

    Philippe, F.; Tassin, V.; Depierreux, S.; Gauthier, P.; Masson-Laborde, P. E.; Monteil, M. C.; Seytor, P.; Villette, B.; Lasinski, B.; Park, H. S.; Ross, J. S.; Amendt, P.; Döppner, T.; Hinkel, D. E.; Wallace, R.; Williams, E.; Michel, P.; Frenje, J.; Gatu-Johnson, M.; Li, C. K.; Petrasso, R.; Glebov, V.; Sorce, C.; Stoeckl, C.; Nikroo, A.; Giraldez, E.

    2014-07-01

    A direct experimental comparison of rugby-shaped and cylindrical shaped gas-filled hohlraums on the Omega laser facility demonstrates that higher coupling and minimal backscatter can be achieved in the rugby geometry, leading to significantly enhanced implosion performance. A nearly 50% increase of x-ray drive is associated with earlier bangtime and increase of neutron production. The observed drive enhancement from rugby geometry in this study is almost twice stronger than in previously published results.

  13. Demonstrated high performance of gas-filled rugby-shaped hohlraums on Omega

    International Nuclear Information System (INIS)

    Philippe, F.; Villette, B.; Michel, P.; Petrasso, R.; Stoeckl, C.; Giraldez, E.; Tassin, V.; Depierreux, S.; Gauthier, P.; Masson-Laborde, P. E.; Monteil, M. C.; Seytor, P.; Lasinski, B.; Park, H. S.; Ross, J. S.; Amendt, P.; Döppner, T.; Hinkel, D. E.; Wallace, R.; Williams, E.

    2014-01-01

    A direct experimental comparison of rugby-shaped and cylindrical shaped gas-filled hohlraums on the Omega laser facility demonstrates that higher coupling and minimal backscatter can be achieved in the rugby geometry, leading to significantly enhanced implosion performance. A nearly 50% increase of x-ray drive is associated with earlier bangtime and increase of neutron production. The observed drive enhancement from rugby geometry in this study is almost twice stronger than in previously published results

  14. Demonstrated high performance of gas-filled rugby-shaped hohlraums on Omega

    Energy Technology Data Exchange (ETDEWEB)

    Philippe, F. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Tassin, V. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Depierreux, S. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Gauthier, P. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Masson-Laborde, P. E. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Monteil, M. C. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Seytor, P. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Villette, B. [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA), Arpajon (France); Lasinski, B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Park, H. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ross, J. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Amendt, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Doeppner, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hinkel, D. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wallace, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Williams, E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Michel, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Frenje, J. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; Gatu-Johnson, M. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; Li, C. K. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; Petrasso, R. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; Glebov, V. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics; Sorce, C. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics; Stoeckl, C. [Univ. of Rochester, NY (United States). Lab. for Laser Energetics; Nikroo, A. [General Atomics, San Diego, CA (United States); Giraldez, E. [General Atomics, San Diego, CA (United States)

    2014-07-25

    A direct experimental comparison of rugby-shaped and cylindrical shaped gas-filled hohlraums on the Omega laser facility demonstrates that higher coupling and minimal backscatter can be achieved in the rugby geometry, leading to significantly enhanced implosion performance. A nearly 50% increase of x-ray drive is associated with earlier bangtime and increase of neutron production. The observed drive enhancement from rugby geometry in this study is almost twice stronger than in previously published results.

  15. Multi-keV x-ray sources from metal-lined cylindrical hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Jacquet, L.; Girard, F.; Primout, M.; Villette, B.; Stemmler, Ph. [CEA, DAM, DIF, F-91297 Arpajon (France)

    2012-08-15

    As multi-keV x-ray sources, plastic hohlraums with inner walls coated with titanium, copper, and germanium have been fired on Omega in September 2009. For all the targets, the measured and calculated multi-keV x-ray power time histories are in a good qualitative agreement. In the same irradiation conditions, measured multi-keV x-ray conversion rates are {approx}6%-8% for titanium, {approx}2% for copper, and {approx}0.5% for germanium. For titanium and copper hohlraums, the measured conversion rates are about two times higher than those given by hydroradiative computations. Conversely, for the germanium hohlraum, a rather good agreement is found between measured and computed conversion rates. To explain these findings, multi-keV integrated emissivities calculated with RADIOM [M. Busquet, Phys. Fluids 85, 4191 (1993)], the nonlocal-thermal-equilibrium atomic physics model used in our computations, have been compared to emissivities obtained from different other models. These comparisons provide an attractive way to explain the discrepancies between experimental and calculated quantitative results.

  16. Multi-keV x-ray sources from metal-lined cylindrical hohlraums

    International Nuclear Information System (INIS)

    Jacquet, L.; Girard, F.; Primout, M.; Villette, B.; Stemmler, Ph.

    2012-01-01

    As multi-keV x-ray sources, plastic hohlraums with inner walls coated with titanium, copper, and germanium have been fired on Omega in September 2009. For all the targets, the measured and calculated multi-keV x-ray power time histories are in a good qualitative agreement. In the same irradiation conditions, measured multi-keV x-ray conversion rates are ∼6%-8% for titanium, ∼2% for copper, and ∼0.5% for germanium. For titanium and copper hohlraums, the measured conversion rates are about two times higher than those given by hydroradiative computations. Conversely, for the germanium hohlraum, a rather good agreement is found between measured and computed conversion rates. To explain these findings, multi-keV integrated emissivities calculated with RADIOM [M. Busquet, Phys. Fluids 85, 4191 (1993)], the nonlocal-thermal-equilibrium atomic physics model used in our computations, have been compared to emissivities obtained from different other models. These comparisons provide an attractive way to explain the discrepancies between experimental and calculated quantitative results.

  17. Multi-keV x-ray sources from metal-lined cylindrical hohlraums

    Science.gov (United States)

    Jacquet, L.; Girard, F.; Primout, M.; Villette, B.; Stemmler, Ph.

    2012-08-01

    As multi-keV x-ray sources, plastic hohlraums with inner walls coated with titanium, copper, and germanium have been fired on Omega in September 2009. For all the targets, the measured and calculated multi-keV x-ray power time histories are in a good qualitative agreement. In the same irradiation conditions, measured multi-keV x-ray conversion rates are ˜6%-8% for titanium, ˜2% for copper, and ˜0.5% for germanium. For titanium and copper hohlraums, the measured conversion rates are about two times higher than those given by hydroradiative computations. Conversely, for the germanium hohlraum, a rather good agreement is found between measured and computed conversion rates. To explain these findings, multi-keV integrated emissivities calculated with RADIOM [M. Busquet, Phys. Fluids 85, 4191 (1993)], the nonlocal-thermal-equilibrium atomic physics model used in our computations, have been compared to emissivities obtained from different other models. These comparisons provide an attractive way to explain the discrepancies between experimental and calculated quantitative results.

  18. Mode-selective symmetry control for indirect-drive inertial confinement fusion hohlraums

    International Nuclear Information System (INIS)

    Vesey, R. A.; Slutz, S. A.; Herrmann, M. C.; Mehlhorn, T. A.; Campbell, R. B.

    2008-01-01

    Achieving a high degree of radiation symmetry is a critical feature of target designs for indirect-drive inertial confinement fusion. Typically, the radiation flux incident on the capsule is required to be uniform to 1% or better. It is generally possible to design a hohlraum that provides low values of higher-order asymmetry (Legendre mode P 10 and above) due to geometric averaging effects. Because low-order intrinsic asymmetry (e.g., Legendre modes P 2 and P 4 ) are less strongly reduced by geometric averaging alone, the development of innovative control techniques has been an active area of research in the inertial fusion community over the years. Shields placed inside the hohlraum are one example of a technique that has often been proposed and incorporated into hohlraum target designs. Simple mathematical considerations are presented indicating that radiation shields may be designed to specifically tune lower-order modes (e.g., P 4 ) without deleterious effects on the higher order modes. Two-dimensional view factor and radiation-hydrodynamics simulations confirm these results and support such a path to achieving a highly symmetric x-ray flux. The term ''mode-selective'' is used because these shields, essentially ring structures offset from the capsule, are designed to affect only a specific Legendre mode (or multiple modes) of interest

  19. Demonstration of high coupling efficiency to Al capsule in rugby hohlraum on NIF

    Science.gov (United States)

    Ping, Y.; Smalyuk, V.; Amendt, P.; Bennett, D.; Chen, H.; Dewald, E.; Goyon, C.; Graziani, F.; Johnson, S.; Khan, S.; Landen, O.; Nikroo, A.; Pino, J.; Ralph, J.; Seugling, R.; Strozzi, D.; Tipton, R.; Tommasini, R.; Wang, M.; Loomis, E.; Merritt, E.; Montgomery, D.

    2017-10-01

    A new design of the double-shell approach predicts a high coupling efficiency from the hohlraum to the capsule, with 700 kJ in the capsule instead of 200kJ in the conventional low-Z single-shell scheme, improving prospects of double-shell performance. A recent experiment on NIF has evaluated a first step toward this goal of energy coupling using 0.7x subscale Al capsule, Au rugby hohlraum and 1MJ drive. A shell velocity of 150 μm/ns was measured, DANTE peak temperature of 255 eV was measured, and shell kinetic energy of 36 kJ was inferred using a rocket model, all close to predictions and consistent with 330kJ of total energy coupled to the capsule. Data analysis and more results from subsequent experiments will be presented. In the next step, an additional 2x increase of total coupled energy up to 700 kJ is projected for full-scale 2-MJ drive in U Rugby hohlraum. This work was performed under DOE contract DE-AC52-07NA27344.

  20. Convergent ablation measurements with gas-filled rugby hohlraum on OMEGA

    Science.gov (United States)

    Casner, A.; Jalinaud, T.; Galmiche, D.

    2016-03-01

    Convergent ablation experiments with gas-filled rugby hohlraum were performed for the first time on the OMEGA laser facility. A time resolved 1D streaked radiography of capsule implosion is acquired in the direction perpendicular to hohlraum axis, whereas a 2D gated radiography is acquired at the same time along the hohlraum axis on a x-ray framing camera. The implosion trajectory has been measured for various kinds of uniformly doped ablators, including germanium-doped and silicon-doped polymers (CH), at two different doping fraction (2% and 4% at.). Our experiments aimed also at measuring the implosion performance of laminated capsules. A laminated ablator is constituted by thin alternate layers of un-doped and doped CH. It has been previously shown in planar geometry that laminated ablators could mitigate Rayleigh Taylor growth at ablation front. Our results confirm that the implosion of a capsule constituted with a uniform or laminated ablator behaves similarly, in accordance with post-shot simulations performed with the CEA hydrocode FCI2.

  1. Convergent ablation measurements with gas-filled rugby hohlraum on OMEGA

    International Nuclear Information System (INIS)

    Casner, A.; Jalinaud, T.; Galmiche, D.

    2016-01-01

    Convergent ablation experiments with gas-filled rugby hohlraum were performed for the first time on the OMEGA laser facility. A time resolved 1D streaked radiography of capsule implosion is acquired in the direction perpendicular to hohlraum axis, whereas a 2D gated radiography is acquired at the same time along the hohlraum axis on a x-ray framing camera. The implosion trajectory has been measured for various kinds of uniformly doped ablators, including germanium-doped and silicon-doped polymers (CH), at two different doping fraction (2% and 4% at.). Our experiments aimed also at measuring the implosion performance of laminated capsules. A laminated ablator is constituted by thin alternate layers of un-doped and doped CH. It has been previously shown in planar geometry that laminated ablators could mitigate Rayleigh Taylor growth at ablation front. Our results confirm that the implosion of a capsule constituted with a uniform or laminated ablator behaves similarly, in accordance with post-shot simulations performed with the CEA hydrocode FCI2. (paper)

  2. Generation and Beaming of Early Hot Electrons onto the Capsule in Laser-Driven Ignition Hohlraums

    Science.gov (United States)

    Dewald, E. L.; Hartemann, F.; Michel, P.; Milovich, J.; Hohenberger, M.; Pak, A.; Landen, O. L.; Divol, L.; Robey, H. F.; Hurricane, O. A.; Döppner, T.; Albert, F.; Bachmann, B.; Meezan, N. B.; MacKinnon, A. J.; Callahan, D.; Edwards, M. J.

    2016-02-01

    In hohlraums for inertial confinement fusion (ICF) implosions on the National Ignition Facility, suprathermal hot electrons, generated by laser plasma instabilities early in the laser pulse ("picket") while blowing down the laser entrance hole (LEH) windows, can preheat the capsule fuel. Hard x-ray imaging of a Bi capsule surrogate and of the hohlraum emissions, in conjunction with the measurement of time-resolved bremsstrahlung spectra, allows us to uncover for the first time the directionality of these hot electrons and infer the capsule preheat. Data and Monte Carlo calculations indicate that for most experiments the hot electrons are emitted nearly isotropically from the LEH. However, we have found cases where a significant fraction of the generated electrons are emitted in a collimated beam directly towards the capsule poles, where their local energy deposition is up to 10 × higher than the average preheat value and acceptable levels for ICF implosions. The observed "beaming" is consistent with a recently unveiled multibeam stimulated Raman scattering model [P. Michel et al., Phys. Rev. Lett. 115, 055003 (2015)], where laser beams in a cone drive a common plasma wave on axis. Finally, we demonstrate that we can control the amount of generated hot electrons by changing the laser pulse shape and hohlraum plasma.

  3. Improved Understanding of Implosion Symmetry through New Experimental Techniques Connecting Hohlraum Dynamics with Laser Beam Deposition

    Science.gov (United States)

    Ralph, Joseph; Salmonson, Jay; Dewald, Eduard; Bachmann, Benjamin; Edwards, John; Graziani, Frank; Hurricane, Omar; Landen, Otto; Ma, Tammy; Masse, Laurent; MacLaren, Stephen; Meezan, Nathan; Moody, John; Parrilla, Nicholas; Pino, Jesse; Sacks, Ryan; Tipton, Robert

    2017-10-01

    Understanding what affects implosion symmetry has been a challenge for scientists designing indirect drive inertial confinement fusion experiments on the National Ignition Facility (NIF). New experimental techniques and data analysis have been employed aimed at improving our understanding of the relationship between hohlraum dynamics and implosion symmetry. Thin wall imaging data allows for time-resolved imaging of 10 keV Au l-band x-rays providing for the first time on the NIF, a spatially resolved measurement of laser deposition with time. In the work described here, we combine measurements from the thin wall imaging with time resolved views of the interior of the hohlraum. The measurements presented are compared to hydrodynamic simulations as well as simplified physics models. The goal of this work is to form a physical picture that better explains the relationship of the hohlraum dynamics and capsule ablator on laser beam propagation and implosion symmetry. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344.

  4. Proton imaging of hohlraum plasma stagnation in inertial-confinement-fusion experiments

    International Nuclear Information System (INIS)

    Li, C.K.; Séguin, F.H.; Frenje, J.A.; Sinenian, N.; Rosenberg, M.J.; Manuel, M.J.-E; Rinderknecht, H.G.; Zylstra, A.B.; Petrasso, R.D.; Amendt, P.A.; Landen, O.L.; Mackinnon, A.J.; Town, R.P.J.; Wilks, S.C.; Betti, R.; Meyerhofer, D.D.; Soures, J.M.; Hund, J.; Kilkenny, J.D.; Nikroo, A.

    2013-01-01

    Proton radiography of the spatial structure and temporal evolution of plasma blowing off from a hohlraum wall reveals how the fill gas compresses the wall blow-off, inhibits plasma jet formation and impedes plasma stagnation in the hohlraum interior. The roles of spontaneously generated electric and magnetic fields in hohlraum dynamics and capsule implosions are demonstrated. The heat flux is shown to rapidly convect the magnetic field due to the Nernst effect, which is shown to be ∼10 times faster than convection by the plasma fluid from expanded wall blow-off (v N ∼ 10v). This leads to inhibition of heat transfer from the gas region in the laser beam paths to the surrounding cold gas, resulting in a local plasma temperature increase. The experiments show that interpenetration of the two materials (gas and wall) occurs due to the classical Rayleigh–Taylor instability as the lighter, decelerating ionized fill gas pushes against the heavier, expanding gold wall blow-off. This experiment provides physics insight into the effects of fill gas on x-ray-driven implosions, and would impact the ongoing ignition experiments at the National Ignition Facility. (paper)

  5. First experimental comparisons of laser-plasma interactions between spherical and cylindrical hohlraums at SGIII laser facility

    Directory of Open Access Journals (Sweden)

    Yaohua Chen

    2017-03-01

    Full Text Available We present our recent laser-plasmas instability (LPI comparison experiment at the SGIII laser facility between the spherical and cylindrical hohlraums. Three kinds of filling are considered: vacuum, gas-filling with or without a capsule inside. A spherical hohlraum of 3.6 mm in diameter, and a cylindrical hohlraum of 2.4 mm × 4.3 mm are used. The capsule diameter is 0.96 mm. A flat-top laser pulse with 3 ns duration and up to 92.73 kJ energy is used. The experiment has shown that the LPI level in the spherical hohlraum is close to that of the outer beam in the cylindrical hohlraum, while much lower than that of the inner beam. The experiment is further simulated by using our 2-dimensional radiation hydrodynamic code LARED-Integration, and the laser back-scattering fraction and the stimulated Raman scatter (SRS spectrum are post-processed by the high efficiency code of laser interaction with plasmas HLIP. According to the simulation, the plasma waves are strongly damped and the SRS is mainly developed at the plasma conditions of electron density from 0.08 nc to 0.1 nc and electron temperature from 1.5 keV to 2.0 keV inside the hohlraums. However, obvious differences between the simulation and experiment are found, such as that the SRS back-scattering is underestimated, and the numerical SRS spectrum peaks at a larger wavelength and at a later time than the data. These differences indicate that the development of a 3D radiation hydrodynamic code, with more accurate physics models, is mandatory for spherical hohlraum study.

  6. Crystal spectroscopy of silicon aero-gel end-caps driven by a dynamic hohlraum on Z

    International Nuclear Information System (INIS)

    Nash, T.J.; Sanford, T.W.L.; Mock, R.C.; Leeper, R.J.; Chandler, G.A.; Bailey, J.E.; McKenney, J.L.; Mehlhorn, T.A.; Seaman, J.F.; McGurn, J.; Schroen, D.; Russell, C.; Lake, P.E.; Jobe, D.O.; Gilliland, T.; Nielsen, D.S.; Lucas, J.; Moore, T.; Torres, J.A.; MacFarlane, J.J.; Apruzese, J.P.; Chrien, R.; Idzorek, G.; Peterson, D.L.; Watt, R.

    2005-01-01

    We present results from crystal spectroscopic analysis of silicon aero-gel foams heated by dynamic hohlraums on Z. The dynamic hohlraum on Z creates a radiation source with a 230-eV average temperature over a 2.4-mm diameter. In these experiments silicon aero-gel foams with 10-mg/cm3 densities and 1.7-mm lengths were placed on both ends of the dynamic hohlraum. Several crystal spectrometers were placed both above and below the z-pinch to diagnose the temperature of the silicon aero-gel foam using the K-shell lines of silicon. The crystal spectrometers were (1) temporally integrated and spatially resolved, (2) temporally resolved and spatially integrated, and (3) both temporally and spatially resolved. The results indicate that the dynamic hohlraum heats the silicon aero-gel to approximately 150-eV at peak power. As the dynamic hohlraum source cools after peak power the silicon aero-gel continues to heat and jets axially at an average velocity of approximately 50-cm/μs. The spectroscopy has also shown that the reason for the up/down asymmetry in radiated power on Z is that tungsten enters the line-of-sight on the bottom of the machine much more than on the top

  7. Early-time radiation flux symmetry optimization and its effect on gas-filled hohlraum ignition targets on the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Milovich, J. L., E-mail: milovich1@llnl.gov; Dewald, E. L.; Pak, A.; Michel, P.; Town, R. P. J.; Bradley, D. K.; Landen, O.; Edwards, M. J. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2016-03-15

    Achieving ignition on the National Ignition Facility (NIF) is tied to our ability to control and minimize deviations from sphericity of the capsule implosion. Low-mode asymmetries of the hot spot result from the combined effect of radiation drive asymmetries throughout the laser pulse and initial roughness on the capsule surface. In this paper, we report on simulations and experiments designed to assess, measure, and correct the drive asymmetries produced by the early-time (≈first 2 ns or “picket”) period of the laser pulse. The drive asymmetry during the picket is commonly thought to introduce distortions in the hot-spot shape at ignition time. However, a more subtle effect not previously considered is that it also leads to an asymmetry in shock velocity and timing, thereby increasing the fuel adiabat and reducing the margin for ignition. It is shown via hydrodynamic simulations that minimizing this effect requires that the early-time asymmetry be kept below 7.5% in the second Legendre mode (P{sub 2}), thus keeping the loss of performance margin below ≈10% for a layered implosion. Asymmetries during the picket of the laser pulse are measured using the instantaneous self-emission of a high-Z re-emission sphere in place of an ignition capsule in a hohlraum with large azimuthal diagnostic windows. Three dimensional simulations using the code HYDRA (to capture the effect of non-azimuthal hohlraum features) coupled to a cross-beam energy transfer model [Michel et al., Phys. Plasmas 17, 056305 (2010)] are used to establish the surrogacy of the re-emit target and to assess the early-time drive symmetry. Calculations using this model exhibit the same sensitivity to variations in the relative input powers between the different cones of NIF beams as measured for the “Rev5” CH target [Haan et al., Phys Plasmas 18, 051001 (2011)] and reported by Dewald et al. [Phys. Rev. Lett. 111, 235001 (2013)]. The same methodology applied to recently improved implosions

  8. Early-time radiation flux symmetry optimization and its effect on gas-filled hohlraum ignition targets on the National Ignition Facility

    International Nuclear Information System (INIS)

    Milovich, J. L.; Dewald, E. L.; Pak, A.; Michel, P.; Town, R. P. J.; Bradley, D. K.; Landen, O.; Edwards, M. J.

    2016-01-01

    Achieving ignition on the National Ignition Facility (NIF) is tied to our ability to control and minimize deviations from sphericity of the capsule implosion. Low-mode asymmetries of the hot spot result from the combined effect of radiation drive asymmetries throughout the laser pulse and initial roughness on the capsule surface. In this paper, we report on simulations and experiments designed to assess, measure, and correct the drive asymmetries produced by the early-time (≈first 2 ns or “picket”) period of the laser pulse. The drive asymmetry during the picket is commonly thought to introduce distortions in the hot-spot shape at ignition time. However, a more subtle effect not previously considered is that it also leads to an asymmetry in shock velocity and timing, thereby increasing the fuel adiabat and reducing the margin for ignition. It is shown via hydrodynamic simulations that minimizing this effect requires that the early-time asymmetry be kept below 7.5% in the second Legendre mode (P_2), thus keeping the loss of performance margin below ≈10% for a layered implosion. Asymmetries during the picket of the laser pulse are measured using the instantaneous self-emission of a high-Z re-emission sphere in place of an ignition capsule in a hohlraum with large azimuthal diagnostic windows. Three dimensional simulations using the code HYDRA (to capture the effect of non-azimuthal hohlraum features) coupled to a cross-beam energy transfer model [Michel et al., Phys. Plasmas 17, 056305 (2010)] are used to establish the surrogacy of the re-emit target and to assess the early-time drive symmetry. Calculations using this model exhibit the same sensitivity to variations in the relative input powers between the different cones of NIF beams as measured for the “Rev5” CH target [Haan et al., Phys Plasmas 18, 051001 (2011)] and reported by Dewald et al. [Phys. Rev. Lett. 111, 235001 (2013)]. The same methodology applied to recently improved implosions using

  9. Early-time radiation flux symmetry optimization and its effect on gas-filled hohlraum ignition targets on the National Ignition Facility

    Science.gov (United States)

    Milovich, J. L.; Dewald, E. L.; Pak, A.; Michel, P.; Town, R. P. J.; Bradley, D. K.; Landen, O.; Edwards, M. J.

    2016-03-01

    Achieving ignition on the National Ignition Facility (NIF) is tied to our ability to control and minimize deviations from sphericity of the capsule implosion. Low-mode asymmetries of the hot spot result from the combined effect of radiation drive asymmetries throughout the laser pulse and initial roughness on the capsule surface. In this paper, we report on simulations and experiments designed to assess, measure, and correct the drive asymmetries produced by the early-time (≈first 2 ns or "picket") period of the laser pulse. The drive asymmetry during the picket is commonly thought to introduce distortions in the hot-spot shape at ignition time. However, a more subtle effect not previously considered is that it also leads to an asymmetry in shock velocity and timing, thereby increasing the fuel adiabat and reducing the margin for ignition. It is shown via hydrodynamic simulations that minimizing this effect requires that the early-time asymmetry be kept below 7.5% in the second Legendre mode (P2), thus keeping the loss of performance margin below ≈10% for a layered implosion. Asymmetries during the picket of the laser pulse are measured using the instantaneous self-emission of a high-Z re-emission sphere in place of an ignition capsule in a hohlraum with large azimuthal diagnostic windows. Three dimensional simulations using the code HYDRA (to capture the effect of non-azimuthal hohlraum features) coupled to a cross-beam energy transfer model [Michel et al., Phys. Plasmas 17, 056305 (2010)] are used to establish the surrogacy of the re-emit target and to assess the early-time drive symmetry. Calculations using this model exhibit the same sensitivity to variations in the relative input powers between the different cones of NIF beams as measured for the "Rev5" CH target [Haan et al., Phys Plasmas 18, 051001 (2011)] and reported by Dewald et al. [Phys. Rev. Lett. 111, 235001 (2013)]. The same methodology applied to recently improved implosions using different

  10. Exploring the limits of case-to-capsule ratio, pulse length, and picket energy for symmetric hohlraum drive on the National Ignition Facility Laser

    Science.gov (United States)

    Callahan, D. A.; Hurricane, O. A.; Ralph, J. E.; Thomas, C. A.; Baker, K. L.; Benedetti, L. R.; Berzak Hopkins, L. F.; Casey, D. T.; Chapman, T.; Czajka, C. E.; Dewald, E. L.; Divol, L.; Döppner, T.; Hinkel, D. E.; Hohenberger, M.; Jarrott, L. C.; Khan, S. F.; Kritcher, A. L.; Landen, O. L.; LePape, S.; MacLaren, S. A.; Masse, L. P.; Meezan, N. B.; Pak, A. E.; Salmonson, J. D.; Woods, D. T.; Izumi, N.; Ma, T.; Mariscal, D. A.; Nagel, S. R.; Kline, J. L.; Kyrala, G. A.; Loomis, E. N.; Yi, S. A.; Zylstra, A. B.; Batha, S. H.

    2018-05-01

    We present a data-based model for low mode asymmetry in low gas-fill hohlraum experiments on the National Ignition Facility {NIF [Moses et al., Fusion Sci. Technol. 69, 1 (2016)]} laser. This model is based on the hypothesis that the asymmetry in these low fill hohlraums is dominated by the hydrodynamics of the expanding, low density, high-Z (gold or uranium) "bubble," which occurs where the intense outer cone laser beams hit the high-Z hohlraum wall. We developed a simple model which states that the implosion symmetry becomes more oblate as the high-Z bubble size becomes large compared to the hohlraum radius or the capsule size becomes large compared to the hohlraum radius. This simple model captures the trends that we see in data that span much of the parameter space of interest for NIF ignition experiments. We are now using this model as a constraint on new designs for experiments on the NIF.

  11. Assessing the prospects for achieving double-shell ignition on the National Ignition Facility using vacuum hohlraums

    Science.gov (United States)

    Amendt, Peter

    2006-10-01

    The goal of demonstrating ignition on the National Ignition Facility (NIF) has motivated a revisit of double-shell (DS) [1] targets as a complementary path to the baseline cryogenic single-shell approach [2]. Benefits of DS targets include room-temperature deuterium-tritium (DT) fuel preparation, minimal hohlraum-plasma-mediated laser backscatter, low threshold-ignition temperatures (4 keV) for relaxed hohlraum x-ray flux asymmetry tolerances [3], and loose shock timing requirements. On the other hand, DS ignition presents several challenges, including room-temperature containment of high-pressure DT (790 atm) in the inner shell; strict concentricity requirements on the two shells; development of nanoporous, low-density, metallic foams for structural support of the inner shell and hydrodynamic instability mitigation; and effective control of perturbation growth on the high-Atwood number interface between the DT fuel and the high-Z inner shell. Recent progress in DS ignition target designs using vacuum hohlraums is described, offering the potential for low levels of laser backscatter from stimulated Raman and Brillouin processes. In addition, vacuum hohlraums have the operational advantages of room temperature fielding and fabrication simplicity, as well as benefiting from extensive benchmarking on the Nova and Omega laser facilities. As an alternative to standard cylindrical hohlraums, a rugby-shaped geometry is also introduced that may provide energetics and symmetry tuning benefits for more robust DS designs with yields exceeding 10 MJ for 2 MJ of 3w laser energy. The recent progress in hohlraum designs and required advanced materials development are scheduled to culminate in a prototype demonstration of a NIF-scale ignition-ready DS in 2007. [1] P. Amendt et al., PoP 9, 2221 (2002). [2] J.D. Lindl et al., PoP 11, 339 (2004). [3] M.N. Chizhkov et al., Laser Part. Beams 23, 261 (2005). In collaboration with C. Cerjan, A. Hamza, J. Milovich and H. Robey.

  12. Reproducibility of hohlraum-driven implosion symmetry on the National Ignition Facility

    Directory of Open Access Journals (Sweden)

    Kyrala G.A.

    2013-11-01

    Full Text Available Indirectly driven Symcap capsules are used at the NIF to obtain information about ignition capsule implosion performance, in particular shape. Symcaps replace the cryogenic fuel layer with an equivalent ablator mass and can be similarly diagnosed. Symcaps are good symmetry surrogates to an ignition capsule after the peak of the drive, radiation-hydrodynamics simulations predict that doping of the symcaps vary the behavior of the implosion. We compare the equatorial shapes of a symcap doped with Si or Ge, as well as examine the reproducibility of the shape measurement using two symcaps with the same hohlraum and laser conditions.

  13. Recent experimental results on ICF target implosions by Z-pinch radiation sources and their relevance to ICF ignition studies

    International Nuclear Information System (INIS)

    Mehlhorn, T A; Bailey, J E; Bennett, G; Chandler, G A; Cooper, G; Cuneo, M E; Golovkin, I; Hanson, D L; Leeper, R J; MacFarlane, J J; Mancini, R C; Matzen, M K; Nash, T J; Olson, C L; Porter, J L; Ruiz, C L; Schroen, D G; Slutz, S A; Varnum, W; Vesey, R A

    2003-01-01

    Inertial confinement fusion capsule implosions absorbing up to 35 kJ of x-rays from a ∼220 eV dynamic hohlraum on the Z accelerator at Sandia National Laboratories have produced thermonuclear D-D neutron yields of (2.6±1.3) x 10 10 . Argon spectra confirm a hot fuel with T e ∼ 1 keV and n e ∼ (1-2) x 10 23 cm -3 . Higher performance implosions will require radiation symmetry control improvements. Capsule implosions in a ∼70 eV double-Z-pinch-driven secondary hohlraum have been radiographed by 6.7 keV x-rays produced by the Z-beamlet laser (ZBL), demonstrating a drive symmetry of about 3% and control of P 2 radiation asymmetries to ±2%. Hemispherical capsule implosions have also been radiographed in Z in preparation for future experiments in fast ignition physics. Z-pinch-driven inertial fusion energy concepts are being developed. The refurbished Z machine (ZR) will begin providing scaling information on capsule and Z-pinch in 2006. The addition of a short pulse capability to ZBL will enable research into fast ignition physics in the combination of ZR and ZBL-petawatt. ZR could provide a test bed to study NIF-relevant double-shell ignition concepts using dynamic hohlraums and advanced symmetry control techniques in the double-pinch hohlraum backlit by ZBL

  14. Recent experimental results on ICF target implosions by Z-pinch radiation sources and their relevance to ICF ignition studies

    International Nuclear Information System (INIS)

    Bailey, James E.; Chandler, Gordon Andrew; Vesey, Roger Alan; Hanson, David Lester; Olson, Craig Lee; Nash, Thomas J.; Matzen, Maurice Keith; Ruiz, Carlos L.; Porter, John Larry Jr.; Cuneo, Michael Edward; Varnum, William S.; Bennett, Guy R.; Cooper, Gary Wayne; Schroen, Diana Grace; Slutz, Stephen A.; MacFarlane, Joseph John; Leeper, Ramon Joe; Golovkin, I.E.; Mehlhorn, Thomas Alan; Mancini, Roberto Claudio

    2003-01-01

    Inertial confinement fusion capsule implosions absorbing up to 35 kJ of x-rays from a ∼220 eV dynamic hohlraum on the Z accelerator at Sandia National Laboratories have produced thermonuclear D-D neutron yields of (2.6 ± 1.3) x 10 10 . Argon spectra confirm a hot fuel with Te ∼ 1 keV and n e ∼ (1-2) x 10 23 cm -3 . Higher performance implosions will require radiation symmetry control improvements. Capsule implosions in a ∼70 eV double-Z-pinch-driven secondary hohlraum have been radiographed by 6.7 keV x-rays produced by the Z-beamlet laser (ZBL), demonstrating a drive symmetry of about 3% and control of P 2 radiation asymmetries to ±2%. Hemispherical capsule implosions have also been radiographed in Z in preparation for future experiments in fast ignition physics. Z-pinch-driven inertial fusion energy concepts are being developed. The refurbished Z machine (ZR) will begin providing scaling information on capsule and Z-pinch in 2006. The addition of a short pulse capability to ZBL will enable research into fast ignition physics in the combination of ZR and ZBL-petawatt. ZR could provide a test bed to study NIF-relevant double-shell ignition concepts using dynamic hohlraums and advanced symmetry control techniques in the double-pinch hohlraum backlit by ZBL.

  15. High performance capsule implosions driven by the Z-pinch dynamic hohlraum

    Energy Technology Data Exchange (ETDEWEB)

    Rochau, G A [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Bailey, J E [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Chandler, G A [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Cooper, G [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Dunham, G S [K-tech Corporation, 10800 Gibson S E, Albuquerque, NM 87123 (United States); Lake, P W [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Leeper, R J [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Lemke, R W [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Mehlhorn, T A [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Nikroo, A [General Atomics, PO Box 85608, San Diego, CA 92186 (United States); Peterson, K J [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Ruiz, C L [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Schroen, D G [General Atomics, PO Box 85608, San Diego, CA 92186 (United States); Slutz, S A [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Steinman, D [General Atomics, PO Box 85608, San Diego, CA 92186 (United States); Stygar, W A [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States); Varnum, W [Sandia National Laboratories, PO Box 5800 MS 1196, Albuquerque, NM 87185 (United States)

    2007-12-15

    The Z-pinch dynamic hohlraum (ZPDH) is a high-power x-ray source that has been used in a variety of high energy-density experiments including inertial confinement fusion (ICF) studies. The system consists of a tungsten wire-array Z pinch that implodes onto a low-density CH{sub 2} foam converter launching a radiating shock that heats the hohlraum to radiation temperatures >200 eV. Through time-gated pinhole camera measurements, the mean shock speed is measured from 28 experiments to be 326 {+-} 4 {mu}m ns{sup -1} with a shot-to-shot standard deviation of 7%. Broad-band x-ray measurements indicate that the shot-to-shot reproducibility in the power emission and pulse-shape of the source shock is <15% and {approx}5%, respectively. Calculations have shown that an ICF capsule placed at the center of the foam in the ZPDH can absorb >40 kJ of x-ray energy, within a factor of 4 of the energy believed sufficient for ICF ignition. The capsule types imploded by the ZPDH have evolved over four years culminating in a design that produces record indirect-drive DD thermonuclear neutron yields of up to 3.5E11.

  16. Demonstration of High Performance in Layered Deuterium-Tritium Capsule Implosions in Uranium Hohlraums at the National Ignition Facility.

    Science.gov (United States)

    Döppner, T; Callahan, D A; Hurricane, O A; Hinkel, D E; Ma, T; Park, H-S; Berzak Hopkins, L F; Casey, D T; Celliers, P; Dewald, E L; Dittrich, T R; Haan, S W; Kritcher, A L; MacPhee, A; Le Pape, S; Pak, A; Patel, P K; Springer, P T; Salmonson, J D; Tommasini, R; Benedetti, L R; Bond, E; Bradley, D K; Caggiano, J; Church, J; Dixit, S; Edgell, D; Edwards, M J; Fittinghoff, D N; Frenje, J; Gatu Johnson, M; Grim, G; Hatarik, R; Havre, M; Herrmann, H; Izumi, N; Khan, S F; Kline, J L; Knauer, J; Kyrala, G A; Landen, O L; Merrill, F E; Moody, J; Moore, A S; Nikroo, A; Ralph, J E; Remington, B A; Robey, H F; Sayre, D; Schneider, M; Streckert, H; Town, R; Turnbull, D; Volegov, P L; Wan, A; Widmann, K; Wilde, C H; Yeamans, C

    2015-07-31

    We report on the first layered deuterium-tritium (DT) capsule implosions indirectly driven by a "high-foot" laser pulse that were fielded in depleted uranium hohlraums at the National Ignition Facility. Recently, high-foot implosions have demonstrated improved resistance to ablation-front Rayleigh-Taylor instability induced mixing of ablator material into the DT hot spot [Hurricane et al., Nature (London) 506, 343 (2014)]. Uranium hohlraums provide a higher albedo and thus an increased drive equivalent to an additional 25 TW laser power at the peak of the drive compared to standard gold hohlraums leading to higher implosion velocity. Additionally, we observe an improved hot-spot shape closer to round which indicates enhanced drive from the waist. In contrast to findings in the National Ignition Campaign, now all of our highest performing experiments have been done in uranium hohlraums and achieved total yields approaching 10^{16} neutrons where more than 50% of the yield was due to additional heating of alpha particles stopping in the DT fuel.

  17. Fluorescence imaging as a diagnostic of M-band x-ray drive condition in hohlraum with fluorescent Si targets

    International Nuclear Information System (INIS)

    Li, Qi; Hu, Zhimin; Yao, Li; Huang, Chengwu; Yuan, Zheng; Zhao, Yang; Xiong, Gang; Qing, Bo; Lv, Min; Zhu, Tuo; Deng, Bo; Li, Jin; Wei, Minxi; Zhan, Xiayu; Li, Jun; Yang, Yimeng; Su, Chunxiao; Yang, Guohong; Zhang, Jiyan; Li, Sanwei

    2017-01-01

    Fluorescence imaging of surrogate Si-doped CH targets has been used to provide a measurement for drive condition of high-energy x-ray (i.e. M-band x-ray) drive symmetry upon the capsule in hohlraum on Shenguang-II laser facility. A series of experiments dedicated to the study of photo-pumping and fluorescence effect in Si-plasma are presented. To investigate the feasibility of fluorescence imaging in Si-plasma, an silicon plasma in Si-foil target is pre-formed at ground state by the soft x-ray from a half-hohlraum, which is then photo-pumped by the K-shell lines from a spatially distinct laser-produced Si-plasma. The resonant Si photon pump is used to improve the fluorescence signal and cause visible image in the Si-foil. Preliminary fluorescence imaging of Si-ball target is performed in both Si-doped and pure Au hohlraum. The usual capsule at the center of the hohlraum is replaced with a solid Si-doped CH-ball (Si-ball). Since the fluorescence is proportional to the photon pump upon the Si-plasma, high-energy x-ray drive symmetry is equal to the fluorescence distribution of the Si-ball. (paper)

  18. pF3D Simulations of Large Outer-Beam Brillouin Scattering from NIF Rugby Hohlraums

    Science.gov (United States)

    Langer, Steven; Strozzi, David; Chapman, Thomas; Amendt, Peter

    2015-11-01

    We assess the cause of large outer-beam stimulated Brillouin scattering (SBS) in a NIF shot with a rugby-shaped hohlraum, which has less wall surface loss and thus higher x-ray drive than a cylindrical hohlraum of the same radius. This shot differed from a prior rugby shot with low SBS in three ways: outer beam pointing, split-pointing of the four beams within each outer-beam quadruplet, and a small amount of neon added to the hohlraum helium fill gas. We use pF3D, a massively-parallel, paraxial-envelope laser plasma interaction code, with plasma profiles from the radiation-hydrodynamics code Lasnex. We determine which change between the two shots increased the SBS by adding them one at a time to the simulations. We compare the simulations to experimental data for total SBS power, its spatial distribution at the lens, and the SBS spectrum. For each shot, we use profiles from Lasnex simulations with and without a model for mix at the hohlraum wall-gas interface. Work performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344. Release number LLNL-ABS-674893.

  19. Usefulness of a Rugby-shaped hohlraum in a Laser M'egaJoule (LMJ) 40-quad configuration

    Science.gov (United States)

    Malinie, G.; Vandenboomgaerde, M.; Bastian, J.; Galmiche, D.; Laffite, S.; Liberatore, S.

    2007-11-01

    The LMJ setup will consist of 60 quads in a 3-cone configuration, at angles 33.2^o, 49^o and 59.5^o. First ignition attempts in indirect drive are planned to be made on the way to the completion of the full facility, with only 40 quads in a 2-cone configuration, at angles 33.2^o and 49^o. By analytic considerations, we show that in a 40-quad configuration, the angular location of the hohlraum outer irradiating ring, as seen from the capsule, must be closer to the laser entrance hole than with the full LMJ. The use of a Rugby-shaped hohlraum instead of a cylinder therefore allows to keep a correct symmetry while reducing the wall surface, which improves the global energetic efficiency of the target. Simplified 2D numerical simulations of Rugby hohlraums are presented, achieving a yield of about 30 MJ with our 1.215 mm-radius, CH-uniform-ablator capsule. These results suggests this kind of hohlraum might be an interesting candidate for 40-quad ignition experiments. Work on optimizing the present design and refining the numerical simulations is currently pursued.

  20. Radiation symmetry control for inertial confinement fusion capsule implosions in double Z-pinch hohlraums on Z

    International Nuclear Information System (INIS)

    Vesey, Roger A.; Cuneo, Michael E.; Porter, John L. Jr.; Adams, Richard G.; Aragon, Rafael A.; Rambo, Patrick K.; Ruggles, Laurence E.; Simpson, Walter W.; Smith, Ian C.; Bennett, Guy R.

    2003-01-01

    The double Z-pinch hohlraum high-yield concept [Hammer et al., Phys. Plasmas 6, 2129 (1999)] utilizes two 63-MA Z pinches to heat separate primary hohlraums at either end of a secondary hohlraum containing the cryogenic fusion capsule. Recent experiments on the Z accelerator [Spielman et al., Phys. Plasmas 5, 2105 (1998)] at Sandia National Laboratories have developed an advanced single-sided power feed, double Z-pinch load to study radiation symmetry and pinch power balance using implosion capsules [Cuneo et al., Phys. Rev. Lett. 88, 215004 (2002)]. Point-projection x-ray imaging with the Z-Beamlet Laser mapped the trajectory and distortion of 2-mm diameter plastic ablator capsules. Using the backlit capsule distortion as a symmetry diagnostic, the ability to predictably tune symmetry at the 2 Legendre mode asymmetry coefficient over a range of ±6% (±2% considering points nearest the optimum) was achieved by varying the length of the cylindrical secondary hohlraum containing the capsule, in agreement with viewfactor and radiation-hydrodynamics simulations

  1. Relationship between symmetry and laser pulse shape in low-fill hohlraums at the National Ignition Facility

    Science.gov (United States)

    MacLaren, Steve; Zylstra, A. B.; Yi, A.; Kline, J. L.; Kyrala, G. A.; Kot, L. B.; Loomis, E. N.; Perry, T. S.; Shah, R. C.; Masse, L. P.; Ralph, J. E.; Khan, S. F.

    2017-10-01

    Typically in indirect-drive inertial confinement fusion (ICF) hohlraums cryogenic helium gas fill is used to impede the motion of the hohlraum wall plasma as it is driven by the laser pulse. A fill of 1 mg/cc He has been used to significantly suppress wall motion in ICF hohlraums at the National Ignition Facility (NIF); however, this level of fill also causes laser-plasma instabilities (LPI) which result in hot electrons, time-dependent symmetry swings and reduction in drive due to increased backscatter. There are currently no adequate models for these phenomena in codes used to simulate integrated ICF experiments. A better compromise is a fill in the range of 0.3 0.6 mg/cc, which has been shown to provide some reduction in wall motion without incurring significant LPI effects. The wall motion in these low-fill hohlraums and the resulting effect on symmetry due to absorption of the inner cone beams by the outer cone plasma can be simulated with some degree of accuracy with the hydrodynamics and inverse Bremsstrahlung models in ICF codes. We describe a series of beryllium capsule implosions in 0.3 mg/cc He fill hohlraums that illustrate the effect of pulse shape on implosion symmetry in the ``low-fill'' regime. In particular, we find the shape of the beginning or ``foot'' of the pulse has significant leverage over the final symmetry of the stagnated implosion. This work was performed under the auspices of the Lawrence Livermore National Security, LLC, (LLNS) under Contract No. DE-AC52-07NA27344.

  2. Parsimonious relevance models

    NARCIS (Netherlands)

    Meij, E.; Weerkamp, W.; Balog, K.; de Rijke, M.; Myang, S.-H.; Oard, D.W.; Sebastiani, F.; Chua, T.-S.; Leong, M.-K.

    2008-01-01

    We describe a method for applying parsimonious language models to re-estimate the term probabilities assigned by relevance models. We apply our method to six topic sets from test collections in five different genres. Our parsimonious relevance models (i) improve retrieval effectiveness in terms of

  3. Progress in z-pinch driven dynamic-hohlraums for high-temperature radiation-flow and ICF experiments at Sandia National Laboratories

    International Nuclear Information System (INIS)

    Sanford, T W L; Nash, T J; Olson, R E; Bliss, D E; Lemke, R W; Olson, C L; Ruiz, C L; Mock, R C; Bailey, J E; Chandler, G A; Cuneo, M E; Leeper, R J; Matzen, M K; Mehlhorn, T A; Slutz, S A; Stygar, W A; Peterson, D L; Chrien, R E; Watt, R G; Roderick, N F; Cooper, G W; Apruzese, J P; Sarkisov, G S; Chittenden, J P; Haines, M G

    2004-01-01

    Progress in understanding the physics of dynamic-hohlraums is reviewed for a system capable of generating 13 TW of axial radiation for high temperature (>200 eV) radiation-flow experiments and ICF capsule implosions

  4. A systematic review of methodology applied during preclinical anesthetic neurotoxicity studies : important issues and lessons relevant to the design of future clinical research

    NARCIS (Netherlands)

    Disma, Nicola; Mondardini, Maria C.; Terrando, Niccolo; Absalom, Anthony R.; Bilotta, Federico

    Preclinical evidence suggests that anesthetic agents harm the developing brain thereby causing long-term neurocognitive impairments. It is not clear if these findings apply to humans, and retrospective epidemiological studies thus far have failed to show definitive evidence that anesthetic agents

  5. Development of soft x-ray tracer diagnostics for hohlraum experiments

    International Nuclear Information System (INIS)

    MacFarlane, J.J.; Cohen, D.H.; Wang, P.; Peterson, R.R.; Moses, G.A.

    1998-04-01

    The purpose of this report is to summarize work performed by the University of Wisconsin during fiscal year 1996 under the NLUF contract DE-FG-96SF21015. This contract involved the development of soft x-ray spectral diagnostics from tracer layers in hohlraum witness plates. This effort was originally intended to be focused on OMEGA experiments, but the experiments were changed to NOVA because initial indirect drive shots had not yet been performed on the OMEGA upgrade. Data were collected in a series of experiments between January 1997 and October 1997. Experiments were delayed somewhat due to bringing up the Hettrick spectrometer on the NOVA target chamber. The tasks related to the planning, carrying out, and modeling of the experiments are outlined in Table 1.1 and detailed in the remainder of this report

  6. Rayleigh-Taylor instabilities in indirect laser drive with rugby-shaped hohlraums

    International Nuclear Information System (INIS)

    Casner, A.; Galmiche, D.; Huser, G.; Jadaud, J.P.; Richard, A.; Liberatore, S.; Vandenboomgaerde, M.

    2009-01-01

    The mastering of the development of hydrodynamic instabilities like Rayleigh-Taylor instabilities is an important milestone on the way to perform efficient laser implosions. The complexity of these instabilities implies an experimental validation of the theoretical models and their computer simulations. An experimental platform involving the Omega laser has allowed us to perform indirect drive with rugby-shaped hohlraums. The experiments have validated the growth of 2- and 3-dimensional initial defects as predicted by theory. We have shown that the 3-dimensional defect saturates for an higher amplitude than the 2-dimensional one does. The experiments have been made by using a plastic shell doped with Germanium (CH:Ge). (A.C.)

  7. Characterizing NIF hohlraum energy and particle transport using mid-Z spectroscopic tracer materials

    Science.gov (United States)

    Moody, J. D.; Barrios, M. A.; Widmann, K.; Suter, L. J.; Liedahl, D. A.; Schneider, M. B.; Thorn, D. B.; Farmer, W. A.; Landen, O. L.; Kauffman, R. L.; Jarrott, C.; Sherlock, M. W.; Chen, H.; Jones, O.; MacLaren, S. A.; Eder, D.; Strozzi, D. J.; Meezan, N. B.; Nikroo, A.; Kroll, J. J.; Johnson, S.; Jaquez, J.; Huang, H.

    2017-10-01

    Line emission from mid-Z dopants placed at several spatial locations is used to determine the electron temperature (Te) and plasma flow in NIF hohlraums. Laser drive ablates the dopant and launches it on a trajectory recorded with a framing camera. Analysis of temporally streaked spectroscopy provides an estimate of the time-resolved Te. The estimated temperature gradients show evidence for significantly restricted thermal conduction. Non-local thermal conductivity can account for part of this; additional effects due to magnetic fields, return-current instabilities, ion acoustic turbulence and other physics are considered. We describe our findings and discuss interpretations. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  8. Hohlraum energetics scaling to 520 TW on the National Ignition Facilitya)

    Science.gov (United States)

    Kline, J. L.; Callahan, D. A.; Glenzer, S. H.; Meezan, N. B.; Moody, J. D.; Hinkel, D. E.; Jones, O. S.; MacKinnon, A. J.; Bennedetti, R.; Berger, R. L.; Bradley, D.; Dewald, E. L.; Bass, I.; Bennett, C.; Bowers, M.; Brunton, G.; Bude, J.; Burkhart, S.; Condor, A.; Di Nicola, J. M.; Di Nicola, P.; Dixit, S. N.; Doeppner, T.; Dzenitis, E. G.; Erbert, G.; Folta, J.; Grim, G.; Glenn, S.; Hamza, A.; Haan, S. W.; Heebner, J.; Henesian, M.; Hermann, M.; Hicks, D. G.; Hsing, W. W.; Izumi, N.; Jancaitis, K.; Jones, O. S.; Kalantar, D.; Khan, S. F.; Kirkwood, R.; Kyrala, G. A.; LaFortune, K.; Landen, O. L.; Lagin, L.; Larson, D.; Pape, S. Le; Ma, T.; MacPhee, A. G.; Michel, P. A.; Miller, P.; Montincelli, M.; Moore, A. S.; Nikroo, A.; Nostrand, M.; Olson, R. E.; Pak, A.; Park, H. S.; Patel, J. P.; Pelz, L.; Ralph, J.; Regan, S. P.; Robey, H. F.; Rosen, M. D.; Ross, J. S.; Schneider, M. B.; Shaw, M.; Smalyuk, V. A.; Strozzi, D. J.; Suratwala, T.; Suter, L. J.; Tommasini, R.; Town, R. P. J.; Van Wonterghem, B.; Wegner, P.; Widmann, K.; Widmayer, C.; Wilkens, H.; Williams, E. A.; Edwards, M. J.; Remington, B. A.; MacGowan, B. J.; Kilkenny, J. D.; Lindl, J. D.; Atherton, L. J.; Batha, S. H.; Moses, E.

    2013-05-01

    Indirect drive experiments have now been carried out with laser powers and energies up to 520 TW and 1.9 MJ. These experiments show that the energy coupling to the target is nearly constant at 84% ± 3% over a wide range of laser parameters from 350 to 520 TW and 1.2 to 1.9 MJ. Experiments at 520 TW with depleted uranium hohlraums achieve radiation temperatures of ˜330 ± 4 eV, enough to drive capsules 20 μm thicker than the ignition point design to velocities near the ignition goal of 370 km/s. A series of three symcap implosion experiments with nearly identical target, laser, and diagnostics configurations show the symmetry and drive are reproducible at the level of ±8.5% absolute and ±2% relative, respectively.

  9. A comparative study of x-ray emission from laser spots in laser-heated hohlraums relative to spots on simple disk targets

    International Nuclear Information System (INIS)

    Ze, F.; Langer, S.H.; Kauffman, R.L.; Kilkenny, J.D.; Landen, O.; Ress, D.; Rosen, M.D.; Suter, L.J.; Wallace, R.J.; Wiedwald, J.D.

    1997-01-01

    In this paper we report the results of experiments that compare the x-ray emission from a laser spot in a radiation-filled hohlraum to that from a similar laser spot on a simple disk target. The studies were done using the Nova laser facility [J. D. Lindl, Phys. Plasmas 2, 3933 (1995)] in its 0.35 μm wavelength, 1 ns square pulse configuration. Focal spot intensities were 2 endash 3.5x10 15 W/cm 2 . X-ray images measured x-ray conversion in a hohlraum and from an isolated disk simultaneously. A laser spot inside a hohlraum emitted more x rays, after subtracting the background emission from the hohlraum walls, than a spot on a disk. Numerical models suggest the enhanced spot emission inside the hohlraum is due to an increase in lateral transport relative to the disk. Filamentation in the hohlraum will also increase the spot size. The models agree fairly well with the results on spot spreading but do not explain the overall increase in conversion efficiency. copyright 1997 American Institute of Physics

  10. The I-Raum: A new shaped hohlraum for improved inner beam propagation in indirectly-driven ICF implosions on the National Ignition Facility

    Science.gov (United States)

    Robey, H. F.; Berzak Hopkins, L.; Milovich, J. L.; Meezan, N. B.

    2018-01-01

    Recent work in indirectly-driven inertial confinement fusion implosions on the National Ignition Facility has indicated that late-time propagation of the inner cones of laser beams (23° and 30°) is impeded by the growth of a "bubble" of hohlraum wall material (Au or depleted uranium), which is initiated by and is located at the location where the higher-intensity outer beams (44° and 50°) hit the hohlraum wall. The absorption of the inner cone beams by this "bubble" reduces the laser energy reaching the hohlraum equator at late time driving an oblate or pancaked implosion, which limits implosion performance. In this article, we present the design of a new shaped hohlraum designed specifically to reduce the impact of this bubble by adding a recessed pocket at the location where the outer cones hit the hohlraum wall. This recessed pocket displaces the bubble radially outward, reducing the inward penetration of the bubble at all times throughout the implosion and increasing the time for inner beam propagation by approximately 1 ns. This increased laser propagation time allows one to drive a larger capsule, which absorbs more energy and is predicted to improve implosion performance. The new design is based on a recent National Ignition Facility shot, N170601, which produced a record neutron yield. The expansion rate and absorption of laser energy by the bubble is quantified for both cylindrical and shaped hohlraums, and the predicted performance is compared.

  11. High coupling efficiency of foam spherical hohlraum driven by 2ω laser light

    Science.gov (United States)

    Chen, Yao-Hua; Lan, Ke; Zheng, Wanguo; Campbell, E. M.

    2018-02-01

    The majority of solid state laser facilities built for laser fusion research irradiate targets with third harmonic light (0.35 μm) up-converted from the fundamental Nd wavelength at 1.05 μm. The motivation for this choice of wavelength is improved laser-plasma coupling. Significant disadvantages to this choice of wavelength are the reduced damage threshold of optical components and the efficiency of energy conversion to third harmonic light. Both these issues are significantly improved if second harmonic (0.53 μm) radiation is used, but theory and experiments have shown lower optical to x-ray energy conversion efficiency and increased levels of laser-plasma instabilities, resulting in reduced laser-target coupling. In this letter, we propose to use a 0.53 μm laser for the laser ignition facilities and use a low density foam wall to increase the coupling efficiency from the laser to the capsule and present two-dimensional radiation-hydrodynamic simulations of 0.53 μm laser light irradiating an octahedral-spherical hohlraum with a low density foam wall. The simulations show that the reduced optical depth of the foam wall leads to an increased laser-light conversion into thermal x-rays and about 10% higher radiation flux on the capsule than that achieved with 0.35 μm light irradiating a solid density wall commonly used in laser indirect drive fusion research. The details of the simulations and their implications and suggestions for wavelength scaling coupled with innovative hohlraum designs will be discussed.

  12. The size and structure of the laser entrance hole in gas-filled hohlraums at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, M. B., E-mail: schneider5@llnl.gov; MacLaren, S. A.; Widmann, K.; Meezan, N. B.; Hammer, J. H.; Yoxall, B. E.; Bell, P. M.; Benedetti, L. R.; Bradley, D. K.; Callahan, D. A.; Dewald, E. L.; Döppner, T.; Eder, D. C.; Edwards, M. J.; Hinkel, D. E.; Hsing, W. W.; Kervin, M. L.; Landen, O. L.; Lindl, J. D.; May, M. J. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States); and others

    2015-12-15

    At the National Ignition Facility, a thermal X-ray drive is created by laser energy from 192 beams heating the inside walls of a gold cylinder called a “hohlraum.” The x-ray drive heats and implodes a fuel capsule. The laser beams enter the hohlraum via laser entrance holes (LEHs) at each end. The LEH radius decreases as heated plasma from the LEH material blows radially inward but this is largely balanced by hot plasma from the high-intensity region in the center of the LEH pushing radially outward. The x-ray drive on the capsule is deduced by measuring the time evolution and spectra of the x-radiation coming out of the LEH and correcting for geometry and for the radius of the LEH. Previously, the LEH radius was measured using time-integrated images in an x-ray band of 3–5 keV (outside the thermal x-ray region). For gas-filled hohlraums, the measurements showed that the LEH radius is larger than that predicted by the standard High Flux radiation-hydrodynamic model by about 10%. A new platform using a truncated hohlraum (“ViewFactor hohlraum”) is described, which allows time-resolved measurements of the LEH radius at thermal x-ray energies from two views, from outside the hohlraum and from inside the hohlraum. These measurements show that the LEH radius closes during the low power part of the pulse but opens up again at peak power. The LEH radius at peak power is larger than that predicted by the models by about 15%–20% and does not change very much with time. In addition, time-resolved images in a >4 keV (non-thermal) x-ray band show a ring of hot, optically thin gold plasma just inside the optically thick LEH plasma. The structure of this plasma varies with time and with Cross Beam Energy Transfer.

  13. [Analysis of clinical relevance applied to 3methods of reducing weight in overweight or obesity followed-up for one year].

    Science.gov (United States)

    Tárraga Marcos, M L; Panisello Royo, J M; Carbayo Herencia, J A; Rosich Domenech, N; Alins Presas, J; Castell Panisello, E; Tárraga López, P J

    To analyse the effect of the use/implementation of 3methods to reduce weight in overweight or obese patients during one year of follow up. The design corresponds to a double-blind, randomised, controlled clinical trial with 3arms, and 12 months of follow-up. Patients were randomised into 3intervention groups: obesity motivational intervention, with a nurse previously trained in motivational intervention by expert psychologists (G1; n=60); lower intensity consultation, non-motivational group, with digital platform support (G2; N=61), and a third group that received recommendations for weight loss and follow-up in Primary Care Clinic (G3; n=59). Anthropometric variables (weight, height, and abdominal-waist circumference) were measured, and the percentage of patients who managed to reduce their weight ≥5% was considered as the main measurement of treatment effectiveness. All groups significantly decreased body weight at the end of the study, with a reduction in G1 (-5.6kg) followed by G2 (-4.3kg), and G3 (-1.7kg), with an overall mean: -3.9kg. The indicators of clinical relevance were in G1/G3: relative risk (RR): 4.99 (95% CI: from 2.71 to 9.18); relative risk reduction (RRR): 399.1% (171.3 to 818.0); Absolute risk reduction (RAR): 65.3% (from 51.5 to 79.1) and NNT: 2 (from 2 to 2). In the G2/G3 groups: RR: 3.01 (from 1.57 to 5.76); RRR: 200.5% (from 57.0 to 475.5); RAR: 32.8% (from 16.9 to 48.7) and NNT: 4 (from 3 to 6). In the G1/G2 groups: RR: 1.66 (from 1.25 to 2.20); RRR: 66.1% (from 25.3 to 120.1); RAR: 32.5% (from 16.6 to 48.4) and NNT: 4 (from 3 to 7). All 3groups were able to reduce weight. Although the group with motivational intervention achieved the greatest decrease, as well as the most favourable clinical relevance indicators. Copyright © 2017 SEH-LELHA. Publicado por Elsevier España, S.L.U. All rights reserved.

  14. The LMJ project - status of our knowledge in hohlraum energetics physics: production and control of the radiation flux; Projet laser megajoule - les etudes et activites dans le domaine de la physique de la cavite (hohlraum): production et controle du flux radiatif

    Energy Technology Data Exchange (ETDEWEB)

    Dattolo, E

    2001-09-01

    CEA-DAM in France is working on Inertial controlled Fusion (ICF) since the beginning of nineties. In an indirect drive scheme, the laser light is converted in X-ray in a hohlraum made with an high-Z material. Part of this radiation flux is absorbed by a micro-balloon filled with DT, placed in the center of the hohlraum, and generates its implosion, ignition and burn. This paper gives the status of our knowledge and studies for production and control of the radiation flux in the hohlraum, in the perspective of the Laser MegaJoule (LMJ). (authors)

  15. Assessing the prospects for achieving double-shell ignition on the National Ignition Facility using vacuum hohlraums

    International Nuclear Information System (INIS)

    Amendt, Peter; Cerjan, C.; Hamza, A.; Hinkel, D. E.; Milovich, J. L.; Robey, H. F.

    2007-01-01

    The goal of demonstrating ignition on the National Ignition Facility [J. D. Lindl et al., Phys. Plasmas 11, 339 (2003)] has motivated a revisit of double-shell (DS) targets as a complementary path to the cryogenic baseline approach. Expected benefits of DS ignition targets include noncryogenic deuterium-tritium (DT) fuel preparation, minimal hohlraum-plasma-mediated laser backscatter, low threshold-ignition temperatures (≅4 keV) for relaxed hohlraum x-ray flux asymmetry tolerances, and minimal (two-) shock timing requirements. On the other hand, DS ignition presents several formidable challenges, encompassing room-temperature containment of high-pressure DT (≅790 atm) in the inner shell, strict concentricity requirements on the two shells ( 2 nanoporous aerogels with suspended Cu particles. A prototype demonstration of an ignition DS is planned for 2008, incorporating the needed novel nanomaterials science developments and the required fabrication tolerances for a realistic ignition attempt after 2010

  16. Predicting the Equilibrium Deuterium-Tritium Fuel Layer Thickness Profile in an Indirect-Drive Hohlraum Capsule

    International Nuclear Information System (INIS)

    Sanchez, Jorge J.; Giedt, Warren H.

    2004-01-01

    A numerical procedure for calculating the equilibrium thickness distribution of a thin layer of deuterium and tritium on the inner surface of an indirect drive target sphere (∼2.0 mm in diameter) is described. Starting with an assumed uniform thickness layer and with specified thermal boundary conditions, the temperature distribution throughout the capsule and hohlraum (including natural convection in the hohlraum gas) is calculated. Results are used to make a first estimate of the final non-uniform thickness distribution of the layer. This thickness distribution is then used to make a second calculation of the temperature distribution with the same boundary conditions. Legendre polynomial coefficients are evaluated for the two temperature distributions and the two thickness profiles. Final equilibrium Legendre coefficients are determined by linear extrapolation. From these coefficients, the equilibrium layer thickness can be computed

  17. Time-dependent, x-ray spectral unfolds and brightness temperatures for intense Li+ ion beam-driven hohlraums

    International Nuclear Information System (INIS)

    Fehl, D.L.; Chandler, G.A.; Biggs, F.; Dukart, R.J.; Moats, A.R.; Leeper, R.J.

    1996-01-01

    X-ray-producing hohlraums are being studied as indirect drives for Inertial Confinement Fusion targets. In a 1994 target series on the PBFAII accelerator, cylindrical hohlraum targets were heated by an intense Li + ion beam and viewed by an array of 13 time-resolved, filtered x-ray detectors (XRDs). The UFO unfold code and its suite of auxiliary functions were used extensively in obtaining time- resolved x-ray spectra and radiation temperatures from this diagnostic. UFO was also used to obtain fitted response functions from calibration data, to simulate data from blackbody x-ray spectra of interest, to determine the suitability of various unfolding parameters (e.g., energy domain, energy partition, smoothing conditions, and basis functions), to interpolate the XRD signal traces, and to unfold experimental data. The simulation capabilities of the code were useful in understanding an anomalous feature in the unfolded spectra at low photon energies (≤ 100 eV). Uncertainties in the differential and energy-integrated unfolded spectra were estimated from uncertainties in the data. The time-history of the radiation temperature agreed well with independent calculations of the wall temperature in the hohlraum

  18. Time-dependent, x-ray spectral unfolds and brightness temperatures for intense Li+ ion beam-driven hohlraums

    International Nuclear Information System (INIS)

    Fehl, D.L.; Chandler, G.A.; Biggs, F.; Dukart, R.J.; Moats, A.R.; Leeper, R.J.

    1997-01-01

    X-ray-producing hohlraums are being studied as indirect drives for inertial confinement fusion targets. In a 1994 target series on the PBFAII accelerator, cylindrical hohlraum targets were heated by an intense Li + ion beam and viewed by an array of 13 time-resolved, filtered x-ray detectors (XRDs). The unfold operator (UFO) code and its suite of auxiliary functions were used extensively in obtaining time-resolved x-ray spectra and radiation temperatures from this diagnostic. The UFO was also used to obtain fitted response functions from calibration data, to simulate data from blackbody x-ray spectra of interest, to determine the suitability of various unfolding parameters (e.g., energy domain, energy partition, smoothing conditions, and basis functions), to interpolate the XRD signal traces, and to unfold experimental data. The simulation capabilities of the code were useful in understanding an anomalous feature in the unfolded spectra at low photon energies (≤100 eV). Uncertainties in the differential and energy-integrated unfolded spectra were estimated from uncertainties in the data. The time endash history of the radiation temperature agreed well with independent calculations of the wall temperature in the hohlraum. copyright 1997 American Institute of Physics

  19. Z-Pinch Generated X-Rays in Static-Wall Hohlraum Geometry Demonstrate Potential for Indirect-Drive ICF Studies

    Energy Technology Data Exchange (ETDEWEB)

    BOWERS,RICHARD; CHANDLER,GORDON A.; HEBRON,DAVID E.; LEEPER,RAMON J.; MATUSLKA,WALTER; MOCK,RAYMOND CECIL; NASH,THOMAS J.; OLSON,CRAIG L.; PETERSON,BOB; PETERSON,DARRELL; RUGGLES,LAURENCE E.; SANFORD,THOMAS W. L.; SIMPSON,WALTER W.; STRUVE,KENNETH W.; VESEY,ROGER A.

    1999-11-01

    Hohlraums of full ignition scale (6-mm diameter by 7-mm length) have been heated by x-rays from a z-pinch magnet on Z to a variety of temperatures and pulse shapes which can be used to simulate the early phases of the National Ignition Facility (NIF) temperature drive. The pulse shape is varied by changing the on-axis target of the z pinch in a static-wall-hohlraum geometry. A 2-{micro}m-thick walled Cu cylindrical target of 8-mm diameter filled with 10 mg/cm{sup 3} CH, for example, produces foot-pulse conditions of {approx}85 eV for a duration of {approx}10 ns, while a solid cylindrical target of 5-mm diameter and 14-mg/cm{sup 3} CH generates first-step-pulse conditions of {approx}122 eV for a duration of a few ns. Alternatively, reducing the hohlraum size (to 4-mm diameter by 4-mm length) with the latter target has increased the peak temperature to {approx}150 eV, which is characteristic of a second-step-pulse temperature. In general, the temperature T of these x-ray driven hohlraums is in agreement with the Planckian relation T{approx}(P/A){sup 1/4}. P is the measured x-ray input power and A is the surface area of the hohlraum. Fully-integrated 2-D radiation-hydrodynamic simulations of the z pinch and subsequent hohlraum heating show plasma densities within the useful volume of the hohlraums to be on the order of air or less.

  20. Z-Pinch Generated X-Rays in Static-Wall Hohlraum Geometry Demonstrate Potential for Indirect-Drive ICF Studies

    International Nuclear Information System (INIS)

    Sandord, T.W.L.; Olson, R.E.; Chandler, G.A.; Hebron, D.E.; Mock, R.C.; Leeper, R.J.; Nash, T.J.; Ruggles, L.E.; Simpson, W.W.; Struve, K.W.; Vesey, R.A.; Bowers, R.L.; Matuska, W.; Peterson, D.L.; Peterson, R.R.

    1999-01-01

    Hohlraums of full ignition scale (6-mm diameter by 7-mm length) have been heated by x-rays from a z-pinch target on Z to a variety of temperatures and pulse shapes which can be used to simulate the early phases of the National Ignition Facility (NIF) temperature drive. The pulse shape is varied by changing the on-axis target of the z pinch in a static-wall-hohlraum geometry. A 2-microm-thick walled Cu cylindrical target of 8-mm diameter filled with 10 mg/cm 3 CH, for example, produces foot-pulse conditions of minus85 eV for a duration of approximately 10 ns, while a solid cylindrical target of 5-mm diameter and 14-mg/cm 3 CH generates first-step-pulse conditions of approximately 122 eV for a duration of a few ns. Alternatively, reducing the hohlraum size (to 4-mm diameter by 4-mm length) with the latter target has increased the peak temperature to approximately 150 eV, which is characteristic of a second-step-pulse temperature. In general, the temperature T of these x-ray driven hohlraums is in agreement with the Planckian relation (T-(P/A) 1/4 ). P is the measured x-ray input power and A is the surface area of the hohlraum. Fully-integrated 2-D radiation-hydrodynamic simulations of the z pinch and subsequent hohlraum heating show plasma densities within the useful volume of the hohlraums to be on the order of air or less

  1. Z-Pinch Generated X-Rays in Static-Wall Hohlraum Geometry Demonstrate Potential for Indirect-Drive ICF Studies

    Energy Technology Data Exchange (ETDEWEB)

    Sandord, T.W.L.; Olson, R.E.; Chandler, G.A.; Hebron, D.E.; Mock, R.C.; Leeper, R.J.; Nash, T.J.; Ruggles, L.E.; Simpson, W.W.; Struve, K.W.; Vesey, R.A.; Bowers, R.L.; Matuska, W.; Peterson, D.L.; Peterson, R.R.

    1999-08-25

    Hohlraums of full ignition scale (6-mm diameter by 7-mm length) have been heated by x-rays from a z-pinch target on Z to a variety of temperatures and pulse shapes which can be used to simulate the early phases of the National Ignition Facility (NIF) temperature drive. The pulse shape is varied by changing the on-axis target of the z pinch in a static-wall-hohlraum geometry. A 2-{micro}m-thick walled Cu cylindrical target of 8-mm diameter filled with 10 mg/cm{sup 3} CH, for example, produces foot-pulse conditions of {minus}85 eV for a duration of {approximately} 10 ns, while a solid cylindrical target of 5-mm diameter and 14-mg/cm{sup 3} CH generates first-step-pulse conditions of {approximately} 122 eV for a duration of a few ns. Alternatively, reducing the hohlraum size (to 4-mm diameter by 4-mm length) with the latter target has increased the peak temperature to {approximately} 150 eV, which is characteristic of a second-step-pulse temperature. In general, the temperature T of these x-ray driven hohlraums is in agreement with the Planckian relation (T-(P/A){sup 1/4}). P is the measured x-ray input power and A is the surface area of the hohlraum. Fully-integrated 2-D radiation-hydrodynamic simulations of the z pinch and subsequent hohlraum heating show plasma densities within the useful volume of the hohlraums to be on the order of air or less.

  2. Z-pinch generated X-rays in static-wall-hohlraum geometry demonstrate potential for indirect-drive ICF studies

    International Nuclear Information System (INIS)

    Sanford, T.W.L.; Olson, R.E.; Mock, R.C.; Chandler, G.A.; Hebron, D.E.; Leeper, R.J.; Nash, T.J.; Ruggles, L.E.; Simpson, W.W.; Struve, K.W.; Vesey, R.A.; Bowers, R.L.; Matuska, W.; Peterson, D.L.; Peterson, R.R.

    2000-01-01

    Hohlraums of full ignition scale (6-mm diameter by 7-mm length) have been heated by x-rays from a z-pinch target on Z to a variety of temperatures and pulse shapes which can be used to simulate the early phases of the National Ignition Facility (NIF) temperature drive. The pulse shape is varied by changing the on-axis target of the z pinch in a static-wall-hohlraum geometry [Fusion Technol. 35, 260 (1999)]. A 2-μm-thick walled Cu cylindrical target of 8-mm diameter filled with 10 mg/cm 3 CH, for example, produces foot-pulse conditions of ∼85 eV for a duration of ∼10 ns, while a solid cylindrical target of 5-mm diameter and 14-mg/cm 3 CH generates first-step-pulse conditions of ∼122 eV for a duration of a few ns. Alternatively, reducing the hohlraum size (to 4-mm diameter by 4-mm length) with the latter target has increased the peak temperature to ∼150 eV, which is characteristic of a second-step-pulse temperature. In general, the temperature T of these x-ray driven hohlraums is in agreement with the Planckian relation T∼(P/A) 1/4 . P is the measured x-ray input power and A is the surface area of the hohlraum. Fully-integrated 2-D radiation hydrodynamic simulations of the z pinch and subsequent hohlraum heating show plasma densities within the useful volume of the hohlraums to be on the order of 10 -3 g/cm 3 or less. (authors)

  3. Z-Pinch Generated X-Rays in Static-Wall Hohlraum Geometry Demonstrate Potential for Indirect-Drive ICF Studies

    International Nuclear Information System (INIS)

    Sanford, Thomas W.L.; Bowers, Richard; Chandler, Gordon A.; Hebron, David E.; Leeper, Ramon J.; Matulska, W Alter; Mock, Raymond Cecil; Nash, Thomas J.; Olson, Craig L.; Peterson, Bob; Peterson, Darrell; Ruggles, Laurence E.; Simpson, Walter W.; Struve, Kenneth W.; Vesey, Roger A.

    1999-01-01

    Hohlraums of full ignition scale (6-mm diameter by 7-mm length) have been heated by x-rays from a z-pinch magnet on Z to a variety of temperatures and pulse shapes which can be used to simulate the early phases of the National Ignition Facility (NIF) temperature drive. The pulse shape is varied by changing the on-axis target of the z pinch in a static-wall-hohlraum geometry. A 2-microm-thick walled Cu cylindrical target of 8-mm diameter filled with 10 mg/cm 3 CH, for example, produces foot-pulse conditions of ∼85 eV for a duration of ∼10 ns, while a solid cylindrical target of 5-mm diameter and 14-mg/cm 3 CH generates first-step-pulse conditions of ∼122 eV for a duration of a few ns. Alternatively, reducing the hohlraum size (to 4-mm diameter by 4-mm length) with the latter target has increased the peak temperature to ∼150 eV, which is characteristic of a second-step-pulse temperature. In general, the temperature T of these x-ray driven hohlraums is in agreement with the Planckian relation T∼(P/A) 1/4 . P is the measured x-ray input power and A is the surface area of the hohlraum. Fully-integrated 2-D radiation-hydrodynamic simulations of the z pinch and subsequent hohlraum heating show plasma densities within the useful volume of the hohlraums to be on the order of air or less

  4. Modal analysis applied to rotor balancing: two relevant technical aspects; Analisis modal aplicado al balanceo de rotores: dos aspectos tecnicos relevantes

    Energy Technology Data Exchange (ETDEWEB)

    Aguirre Romano, Jorge E.; Preciado Delgado, Eduardo [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1991-12-31

    In applying the modal analysis to rotor balancing, it is frequent to find technical matters that are hardly developed in text books or that can only be deducted through a profound and complex study. For this reason, an engineer dedicated to the practice that wishes to deepen in the subject of rotor balancing, can hardly understand these matters, unless they are developed with the specific orientation that relate them with the balancing practice. In this paper two of these subjects related to the definition and recollection of modal parameters are presented: a) the fundamental form of the polar diagrams of response, that can be perfectly circular in certain cases and b) the relationship that exists among the modal forms of a rotor and the distribution of weights that must be placed to balance them in a given way. [Espanol] Al aplicar el analisis modal al balanceo de rotores, es frecuente encontrar temas tecnicos que dificilmente se desarrollan en los libros de texto, o que solo pueden deducirse mediante un estudio profundo y complejo. Por esta razon, un ingeniero dedicado a la practica que desee profundizar en el tema de balanceo de rotores, dificilmente podra comprender estos temas, a no ser que estos sean desarrollados con la orientacion especifica que los relacionen con la practica del balanceo. En este trabajo se presentan dos de esos temas relacionados con la definicion y obtencion de los parametros modales: a) la forma fundamental de los diagramas polares de respuesta, que puede ser circular perfecta en ciertos casos, y b) la relacion que existe entre las formas modales de un rotor y la distribucion de pesos que se deben colocar para balancear un modo dado.

  5. Modal analysis applied to rotor balancing: two relevant technical aspects; Analisis modal aplicado al balanceo de rotores: dos aspectos tecnicos relevantes

    Energy Technology Data Exchange (ETDEWEB)

    Aguirre Romano, Jorge E; Preciado Delgado, Eduardo [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1992-12-31

    In applying the modal analysis to rotor balancing, it is frequent to find technical matters that are hardly developed in text books or that can only be deducted through a profound and complex study. For this reason, an engineer dedicated to the practice that wishes to deepen in the subject of rotor balancing, can hardly understand these matters, unless they are developed with the specific orientation that relate them with the balancing practice. In this paper two of these subjects related to the definition and recollection of modal parameters are presented: a) the fundamental form of the polar diagrams of response, that can be perfectly circular in certain cases and b) the relationship that exists among the modal forms of a rotor and the distribution of weights that must be placed to balance them in a given way. [Espanol] Al aplicar el analisis modal al balanceo de rotores, es frecuente encontrar temas tecnicos que dificilmente se desarrollan en los libros de texto, o que solo pueden deducirse mediante un estudio profundo y complejo. Por esta razon, un ingeniero dedicado a la practica que desee profundizar en el tema de balanceo de rotores, dificilmente podra comprender estos temas, a no ser que estos sean desarrollados con la orientacion especifica que los relacionen con la practica del balanceo. En este trabajo se presentan dos de esos temas relacionados con la definicion y obtencion de los parametros modales: a) la forma fundamental de los diagramas polares de respuesta, que puede ser circular perfecta en ciertos casos, y b) la relacion que existe entre las formas modales de un rotor y la distribucion de pesos que se deben colocar para balancear un modo dado.

  6. Detailed spectral simulations in support of PBFA-Z dynamic hohlraum Z-pinch experiments

    International Nuclear Information System (INIS)

    MacFarlane, J.J.; Wang, P.; Derzon, M.S.; Haill, A.; Nash, T.J.; Peterson, D.L.

    1997-01-01

    In PBFA-Z dynamic hohlraum Z-pinch experiments, 16--18 MA of current is delivered to a load comprises of a tungsten wire array surrounding a low-density cylindrical CH foam. The magnetic field accelerates the W plasma radially inward at velocities ∼ 40--60 cm/micros. The W plasma impacts into the foam, generating a high T R radiation field which diffuses into the foam. The authors are investigating several types of spectral diagnostics which can be used to characterize the time-dependent conditions in the foam. In addition, they are examining the potential ramifications of axial jetting on the interpretation of axial x-ray diagnostics. In the analysis, results from 2-D radiation-magnetohydrodynamics simulations are post-processed using a hybrid spectral analysis code in which low-Z material is treated using a detailed collisional-radiative atomic model, while high-Z material is modeled using LTE UTA (unresolved transition array) opacities. They will present results from recent simulations and discuss ramifications for x-ray diagnostics

  7. An investigation of the opacity of high-Z mixture and implications for inertial confinement fusion hohlraum design

    International Nuclear Information System (INIS)

    Wang, P.; MacFarlane, J.J.; Orzechowski, T.J.

    1997-01-01

    We use an unresolved transition array model to investigate the opacities of high-Z materials and their mixtures which are of interest to indirect-drive inertial confinement fusion hohlraum design. In particular, we report on calculated opacities for pure Au, Gd, and Sm, as well as Au endash Sm and Au endash Gd mixtures. Our results indicate that mixtures of Au endash Gd and Au endash Sm can produce a significant enhancement in the Rosseland mean opacity. Radiation hydrodynamics simulations of Au radiation burnthrough are also presented, and compared with NOVA experimental data. copyright 1997 American Institute of Physics

  8. Symmetry control using beam phasing in ∼0.2 NIF scale high temperature Hohlraum experiment on OMEGA

    International Nuclear Information System (INIS)

    Delamater, Norman D.; Wilson, Goug C.; Kyrala, George A.; Seifter, Achim; Hoffman, N.M.; Dodd, E.; Glebov, V.

    2009-01-01

    Results are shown from recent experiments at the Omega laser facility, using 40 Omega beams driving the hohlraum with 3 cones from each side and up to 19.5 kJ of laser energy. Beam phasing is achieved by decreasing the energy separately in each of the three cones, by 3 kJ, for a total drive energy of 16.5kJ. This results in a more asymmetric drive, which will vary the shape of the imploded symmetry capsule core from round to oblate or prolate in a systematic and controlled manner. These results would be the first demonstration of beam phasing for implosions in such 'high temperature' (275 eV) hohlraums at Omega. Dante measurements confirmed the predicted peak drive temperatures of 275 eV. Implosion core time dependent x-ray images were obtained from framing camera data which show the expected change in symmetry due to beam phasing and which also agree well with post processed hydro code calculations. Time resolved hard x-ray data has been obtained and it was found that the hard x-rays are correlated mainly with the low angle 21 o degree cone.

  9. Low-foot rugby hohlraum experiments on the NIF: Wall-gas mix and a connection with missing x-ray drive energy?

    Science.gov (United States)

    Amendt, Peter; Ross, J. Steven; Schneider, Marilyn; Jones, Oggie; Milovich, Jose; Moody, John

    2014-10-01

    Rugby-shaped hohlraums on the NIF have shown strong symmetry anomalies when simulated with the high-flux model. The wall-gas interface is Rayleigh-Taylor unstable and may lead to the formation of a late-time mix layer that impedes inner- cone propagation, resulting in a drive asymmetry on the capsule. Due to the rugby curvature near the laser entrance hole, the effect of mix may be more pronounced than in cylinders. At the same time a persistent pattern of 15--25% missing energy has been inferred in gas-filled hohlraums (ρ >= 0 . 96 mg/cc). A possible physical connection between formation of a mix layer and the plasma adiabatic lapse rate, where a temperature-gradient reversal is predicted to occur, is explored. Such a profile reversal, in turn, hinders electron conduction to the dense (ρ > 0 . 2 g/cc) Au region responsible for ~900 eV drive x-ray emission, leading to a hotter coronal plasma and reduced hohlraum efficiency. Remedial measures for recovering the loss in hohlraum efficiency through the use of higher-Z gas fills are explored. Prepared by LLNL under Contract DE-AC52-07NA27344.

  10. Effects of the P2 M-band flux asymmetry of laser-driven gold Hohlraums on the implosion of ICF ignition capsule

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yongsheng [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Graduate School, China Academy of Engineering Physics, Beijing 100088 (China); Gu, Jianfa; Wu, Changshu; Song, Peng; Dai, Zhensheng; Li, Shuanggui; Li, Xin; Kang, Dongguo; Gu, Peijun; Zheng, Wudi; Zou, Shiyang [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Ding, Yongkun [Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Lan, Ke; Ye, Wenhua, E-mail: ye-wenhua@iapcm.ac.cn [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Zhang, Weiyan [China Academy of Engineering Physics, Mianyang 621900 (China)

    2016-07-15

    Low-mode asymmetries in the laser-indirect-drive inertial confinement fusion implosion experiments conducted on the National Ignition Facility [G. H. Miller et al., Nucl. Fusion 44, S228 (2004)] are deemed the main obstacles hindering further improvement of the nuclear performance of deuterium-tritium-layered capsules. The dominant seeds of these asymmetries include the P2 and P4 asymmetries of x-ray drives and P2 asymmetry introduced by the supporting “tent.” Here, we explore the effects of another possible seed that can lead to low-mode asymmetric implosions, i.e., the M-band flux asymmetry (MFA) in laser-driven cylindrical gold Hohlraums. It is shown that the M-band flux facilitates the ablation and acceleration of the shell, and that positive P2 MFAs can result in negative P2 asymmetries of hot spots and positive P2 asymmetries of shell's ρR. An oblate or toroidal hot spot, depending on the P2 amplitude of MFA, forms at stagnation. The energy loss of such a hot spot via electron thermal conduction is seriously aggravated not only due to the enlarged hot spot surface but also due to the vortices that develop and help transferring thermal energy from the hotter center to the colder margin of such a hot spot. The cliffs of nuclear performance for the two methodologies of applying MFA (i.e., symmetric flux in the presence of MFA and MFA added for symmetric soft x-ray flux) are obtained locating at 9.5% and 5.0% of P2/P0 amplitudes, respectively.

  11. Effects of the P2 M-band flux asymmetry of laser-driven gold Hohlraums on the implosion of ICF ignition capsule

    Science.gov (United States)

    Li, Yongsheng; Gu, Jianfa; Wu, Changshu; Song, Peng; Dai, Zhensheng; Li, Shuanggui; Li, Xin; Kang, Dongguo; Gu, Peijun; Zheng, Wudi; Zou, Shiyang; Ding, Yongkun; Lan, Ke; Ye, Wenhua; Zhang, Weiyan

    2016-07-01

    Low-mode asymmetries in the laser-indirect-drive inertial confinement fusion implosion experiments conducted on the National Ignition Facility [G. H. Miller et al., Nucl. Fusion 44, S228 (2004)] are deemed the main obstacles hindering further improvement of the nuclear performance of deuterium-tritium-layered capsules. The dominant seeds of these asymmetries include the P2 and P4 asymmetries of x-ray drives and P2 asymmetry introduced by the supporting "tent." Here, we explore the effects of another possible seed that can lead to low-mode asymmetric implosions, i.e., the M-band flux asymmetry (MFA) in laser-driven cylindrical gold Hohlraums. It is shown that the M-band flux facilitates the ablation and acceleration of the shell, and that positive P2 MFAs can result in negative P2 asymmetries of hot spots and positive P2 asymmetries of shell's ρR. An oblate or toroidal hot spot, depending on the P2 amplitude of MFA, forms at stagnation. The energy loss of such a hot spot via electron thermal conduction is seriously aggravated not only due to the enlarged hot spot surface but also due to the vortices that develop and help transferring thermal energy from the hotter center to the colder margin of such a hot spot. The cliffs of nuclear performance for the two methodologies of applying MFA (i.e., symmetric flux in the presence of MFA and MFA added for symmetric soft x-ray flux) are obtained locating at 9.5% and 5.0% of P2/P0 amplitudes, respectively.

  12. Effects of the P2 M-band flux asymmetry of laser-driven gold Hohlraums on the implosion of ICF ignition capsule

    International Nuclear Information System (INIS)

    Li, Yongsheng; Gu, Jianfa; Wu, Changshu; Song, Peng; Dai, Zhensheng; Li, Shuanggui; Li, Xin; Kang, Dongguo; Gu, Peijun; Zheng, Wudi; Zou, Shiyang; Ding, Yongkun; Lan, Ke; Ye, Wenhua; Zhang, Weiyan

    2016-01-01

    Low-mode asymmetries in the laser-indirect-drive inertial confinement fusion implosion experiments conducted on the National Ignition Facility [G. H. Miller et al., Nucl. Fusion 44, S228 (2004)] are deemed the main obstacles hindering further improvement of the nuclear performance of deuterium-tritium-layered capsules. The dominant seeds of these asymmetries include the P2 and P4 asymmetries of x-ray drives and P2 asymmetry introduced by the supporting “tent.” Here, we explore the effects of another possible seed that can lead to low-mode asymmetric implosions, i.e., the M-band flux asymmetry (MFA) in laser-driven cylindrical gold Hohlraums. It is shown that the M-band flux facilitates the ablation and acceleration of the shell, and that positive P2 MFAs can result in negative P2 asymmetries of hot spots and positive P2 asymmetries of shell's ρR. An oblate or toroidal hot spot, depending on the P2 amplitude of MFA, forms at stagnation. The energy loss of such a hot spot via electron thermal conduction is seriously aggravated not only due to the enlarged hot spot surface but also due to the vortices that develop and help transferring thermal energy from the hotter center to the colder margin of such a hot spot. The cliffs of nuclear performance for the two methodologies of applying MFA (i.e., symmetric flux in the presence of MFA and MFA added for symmetric soft x-ray flux) are obtained locating at 9.5% and 5.0% of P2/P0 amplitudes, respectively.

  13. Low-adiabat rugby hohlraum experiments on the National Ignition Facility: Comparison with high-flux modeling and the potential for gas-wall interpenetration

    Energy Technology Data Exchange (ETDEWEB)

    Amendt, Peter, E-mail: amendt1@llnl.gov; Ross, J. Steven; Milovich, Jose L.; Schneider, Marilyn; Storm, Erik; Callahan, Debra A.; Hinkel, Denise; Lasinski, Barbara; Meeker, Don; Michel, Pierre; Moody, John; Strozzi, David [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

    2014-11-15

    Rugby-shaped gold hohlraums driven by a nominal low-adiabat laser pulse shape have been tested on the National Ignition Facility. The rugby affords a higher coupling efficiency than a comparably sized cylinder hohlraum or, alternatively, improved drive symmetry and laser beam clearances for a larger hohlraum with similar cylinder wall area and laser energy. A first (large rugby hohlraum) shot at low energy (0.75 MJ) to test laser backscatter resulted in a moderately oblate CH capsule implosion, followed by a high energy shot (1.3 MJ) that gave a highly oblate compressed core according to both time-integrated and –resolved x-ray images. These implosions used low wavelength separation (1.0 Å) between the outer and inner cones to provide an alternative platform free of significant cross-beam energy transfer for simplified hohlraum dynamics. Post-shot 2- and 3-D radiation-hydrodynamic simulations using the high-flux model [M. D. Rosen et al., High Energy Density Phys. 7, 180 (2011)], however, give nearly round implosions for both shots, in striking contrast with observations. An analytic assessment of Rayleigh-Taylor hydrodynamic instability growth on the gold–helium gas-fill interface shows the potential for significant linear growth, saturation and transition to a highly nonlinear state. Candidate seeds for instability growth include laser speckle during the early-time laser picket episode in the presence of only partial temporal beam smoothing (1-D smoothing by spectral dispersion and polarization smoothing) and intensity modulations from quad-to-quad and beam overlap. Radiation-hydrodynamic 2-D simulations adapted to include a dynamic fall-line mix model across the unstable Au-He interface show good agreement with the observed implosion symmetry for both shots using an interface-to-fall-line penetration fraction of 100%. Physically, the potential development of an instability layer in a rugby hohlraum is tantamount to an enhanced wall motion leading to

  14. Low-adiabat rugby hohlraum experiments on the National Ignition Facility: Comparison with high-flux modeling and the potential for gas-wall interpenetration

    International Nuclear Information System (INIS)

    Amendt, Peter; Ross, J. Steven; Milovich, Jose L.; Schneider, Marilyn; Storm, Erik; Callahan, Debra A.; Hinkel, Denise; Lasinski, Barbara; Meeker, Don; Michel, Pierre; Moody, John; Strozzi, David

    2014-01-01

    Rugby-shaped gold hohlraums driven by a nominal low-adiabat laser pulse shape have been tested on the National Ignition Facility. The rugby affords a higher coupling efficiency than a comparably sized cylinder hohlraum or, alternatively, improved drive symmetry and laser beam clearances for a larger hohlraum with similar cylinder wall area and laser energy. A first (large rugby hohlraum) shot at low energy (0.75 MJ) to test laser backscatter resulted in a moderately oblate CH capsule implosion, followed by a high energy shot (1.3 MJ) that gave a highly oblate compressed core according to both time-integrated and –resolved x-ray images. These implosions used low wavelength separation (1.0 Å) between the outer and inner cones to provide an alternative platform free of significant cross-beam energy transfer for simplified hohlraum dynamics. Post-shot 2- and 3-D radiation-hydrodynamic simulations using the high-flux model [M. D. Rosen et al., High Energy Density Phys. 7, 180 (2011)], however, give nearly round implosions for both shots, in striking contrast with observations. An analytic assessment of Rayleigh-Taylor hydrodynamic instability growth on the gold–helium gas-fill interface shows the potential for significant linear growth, saturation and transition to a highly nonlinear state. Candidate seeds for instability growth include laser speckle during the early-time laser picket episode in the presence of only partial temporal beam smoothing (1-D smoothing by spectral dispersion and polarization smoothing) and intensity modulations from quad-to-quad and beam overlap. Radiation-hydrodynamic 2-D simulations adapted to include a dynamic fall-line mix model across the unstable Au-He interface show good agreement with the observed implosion symmetry for both shots using an interface-to-fall-line penetration fraction of 100%. Physically, the potential development of an instability layer in a rugby hohlraum is tantamount to an enhanced wall motion leading to

  15. Low-adiabat rugby hohlraum experiments on the National Ignition Facility: Comparison with high-flux modeling and the potential for gas-wall interpenetration

    Science.gov (United States)

    Amendt, Peter; Ross, J. Steven; Milovich, Jose L.; Schneider, Marilyn; Storm, Erik; Callahan, Debra A.; Hinkel, Denise; Lasinski, Barbara; Meeker, Don; Michel, Pierre; Moody, John; Strozzi, David

    2014-11-01

    Rugby-shaped gold hohlraums driven by a nominal low-adiabat laser pulse shape have been tested on the National Ignition Facility. The rugby affords a higher coupling efficiency than a comparably sized cylinder hohlraum or, alternatively, improved drive symmetry and laser beam clearances for a larger hohlraum with similar cylinder wall area and laser energy. A first (large rugby hohlraum) shot at low energy (0.75 MJ) to test laser backscatter resulted in a moderately oblate CH capsule implosion, followed by a high energy shot (1.3 MJ) that gave a highly oblate compressed core according to both time-integrated and -resolved x-ray images. These implosions used low wavelength separation (1.0 Å) between the outer and inner cones to provide an alternative platform free of significant cross-beam energy transfer for simplified hohlraum dynamics. Post-shot 2- and 3-D radiation-hydrodynamic simulations using the high-flux model [M. D. Rosen et al., High Energy Density Phys. 7, 180 (2011)], however, give nearly round implosions for both shots, in striking contrast with observations. An analytic assessment of Rayleigh-Taylor hydrodynamic instability growth on the gold-helium gas-fill interface shows the potential for significant linear growth, saturation and transition to a highly nonlinear state. Candidate seeds for instability growth include laser speckle during the early-time laser picket episode in the presence of only partial temporal beam smoothing (1-D smoothing by spectral dispersion and polarization smoothing) and intensity modulations from quad-to-quad and beam overlap. Radiation-hydrodynamic 2-D simulations adapted to include a dynamic fall-line mix model across the unstable Au-He interface show good agreement with the observed implosion symmetry for both shots using an interface-to-fall-line penetration fraction of 100%. Physically, the potential development of an instability layer in a rugby hohlraum is tantamount to an enhanced wall motion leading to hindered

  16. Characterization of the neutron flux in the Hohlraum of the thermal column of the TRIGA Mark III reactor of the ININ; Caracterizacion del flujo neutronico en el Hohlraum de la columna termica del reactor TRIGA Mark III del ININ

    Energy Technology Data Exchange (ETDEWEB)

    Delfin L, A.; Palacios, J.C.; Alonso, G. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: adl@nuclear.inin.mx

    2006-07-01

    Knowing the magnitude of the neutron flux in the reactor irradiation facilities, is so much importance for the operation of the same one, like for the investigation developing. Particularly, knowing with certain precision the spectrum and the neutron flux in the different positions of irradiation of a reactor, it is essential for the evaluation of the results obtained for a certain irradiation experiment. The TRIGA Mark III reactor account with irradiation facilities designed to carry out experimentation, where the reactor is used like an intense neutron source and gamma radiation, what allows to make irradiations of samples or equipment in radiation fields with components and diverse levels in the different facilities, one of these irradiation facilities is the Thermal Column where the Hohlraum is. In this work it was carried out a characterization of the neutron flux inside the 'Hohlraum' of the irradiation facility Thermal Column of the TRIGA Mark III reactor of the Nuclear Center of Mexico to 1 MW of power. It was determined the sub cadmic neutron flux and the epi cadmic by means of the neutron activation technique of thin sheets of gold. The maps of the distribution of the neutron flux for both energy groups in three different positions inside the 'Hohlraum' are presented, these maps were obtained by means of the irradiation of undressed thin activation sheets of gold and covered with cadmium in arrangements of 10 x 12, located parallel to 11.5 cm, 40.5 cm and 70.5 cm to the internal wall of graphite of the installation in inverse address to the position of the reactor core. Starting from the obtained values of neutron flux it was found that, for the same position of the surface of irradiation of the experimental arrangement, the relative differences among the values of neutron flux can be of 80%, and that the differences among different positions of the irradiation surfaces can vary until in a one order of magnitude. (Author)

  17. Assessing the existence of non-LTE behavior in aluminum K-shell diagnostic lines from dynamic hohlraum driven experiments

    International Nuclear Information System (INIS)

    Sherrill, M E

    2015-01-01

    We describe in this work a study designed to obtain insight into the sensitivity of foil targets driven out of local thermodynamic equilibrium (LTE) by an idealized dynamic hohlraum during its brightest phase. This work is motivated by a perceived over-prediction of the plasma temperature by current LTE spectral modeling of opacity experiments performed by Bailey et al at the Sandia Z facility. Although several aspects of this modeling study parallel the SNL/LANL opacity experiments, this work is primarily intended to gain insight into radiatively over-driven systems. The results from this idealized study suggest that a non-LTE population distribution with qualities similar to an LTE distribution at higher material temperatures are possible, and therefore support a further theoretical investigation with experimental parameters. (special issue paper)

  18. Z-pinch driven hohlraums design for the 100 nanoseconds current time scale; Conception de cavites radiatives chauffees par plasma de striction magnetique en regime 100ns

    Energy Technology Data Exchange (ETDEWEB)

    Hamann, F

    2003-12-15

    This work estimates Z-pinch driven hohlraums capabilities to obtain high temperatures (>200 eV). Simple models are proposed to calculate the performances offered by currents of 5 to 100 MA in 100 ns. The one dimensional physics of the Z-pinch at the length scale of its thickness and the hydrodynamics instabilities are studied. Then the enhancement of hohlraums performances with double nested Z-pinches or the use of an axial magnetic field is analysed. Z-pinch direct drive approach for inertial confinement fusion is finally considered. All the presented results are based on theoretical and 2D numerical approach and on the analysis of experimental results which were obtained on the american 'Z' generator. Annexes recall radiation MHD equations and check their validity for Z-pinch implosion. (author)

  19. Progress in symmetric ICF capsule implosions and wire-array z-pinch source physics for double z-pinch driven hohlraums

    International Nuclear Information System (INIS)

    Bliss, David Emery; Vesey, Roger Alan; Rambo, Patrick K.; Lebedev, Sergey V.; Hanson, David L.; Nash, Thomas J.; Yu, Edmund P.; Matzen, Maurice Keith; Afeyan, Bedros B.; Smith, Ian Craig; Stygar, William A.; Porter, John Larry Jr.; Cuneo, Michael Edward; Bennett, Guy R.; Campbell, Robert B.; Sinars, Daniel Brian; Chittenden, Jeremy Paul; Waisman, Eduardo Mario; Mehlhorn, Thomas Alan

    2005-01-01

    Over the last several years, rapid progress has been made evaluating the double-z-pinch indirect-drive, inertial confinement fusion (ICF) high-yield target concept (Hammer et al 1999 Phys. Plasmas 6 2129). We have demonstrated efficient coupling of radiation from two wire-array-driven primary hohlraums to a secondary hohlraum that is large enough to drive a high yield ICF capsule. The secondary hohlraum is irradiated from two sides by z-pinches to produce low odd-mode radiation asymmetry. This double-pinch source is driven from a single electrical power feed (Cuneo et al 2002 Phys. Rev. Lett. 88 215004) on the 20 MA Z accelerator. The double z-pinch has imploded ICF capsules with even-mode radiation symmetry of 3.1 ± 1.4% and to high capsule radial convergence ratios of 14-21 (Bennett et al 2002 Phys. Rev. Lett. 89 245002; Bennett et al 2003 Phys. Plasmas 10 3717; Vesey et al 2003 Phys. Plasmas 10 1854). Advances in wire-array physics at 20 MA are improving our understanding of z-pinch power scaling with increasing drive current. Techniques for shaping the z-pinch radiation pulse necessary for low adiabat capsule compression have also been demonstrated.

  20. Electron temperature measurements inside the ablating plasma of gas-filled hohlraums at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Barrios, M. A.; Liedahl, D. A.; Schneider, M. B.; Jones, O.; Brown, G. V.; Fournier, K. B.; Moore, A. S.; Ross, J. S.; Landen, O.; Kauffman, R. L.; Nikroo, A.; Kroll, J.; Callahan, D. A.; Hinkel, D. E.; Bradley, D.; Moody, J. D. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Regan, S. P. [Laboratory for Laser Energetics, Rochester, New York 14623 (United States); Jaquez, J.; Huang, H. [General Atomics, San Diego, California 92121 (United States); Hansen, S. B. [Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States)

    2016-05-15

    The first measurement of the electron temperature (T{sub e}) inside a National Ignition Facility hohlraum is obtained using temporally resolved K-shell X-ray spectroscopy of a mid-Z tracer dot. Both isoelectronic- and interstage-line ratios are used to calculate the local T{sub e} via the collisional–radiative atomic physics code SCRAM [Hansen et al., High Energy Density Phys 3, 109 (2007)]. The trajectory of the mid-Z dot as it is ablated from the capsule surface and moves toward the laser entrance hole (LEH) is measured using side-on x-ray imaging, characterizing the plasma flow of the ablating capsule. Data show that the measured dot location is farther away from the LEH in comparison to the radiation-hydrodynamics simulation prediction using HYDRA [Marinak et al., Phys. Plasmas 3, 2070 (1996)]. To account for this discrepancy, the predicted simulation T{sub e} is evaluated at the measured dot trajectory. The peak T{sub e}, measured to be 4.2 keV ± 0.2 keV, is ∼0.5 keV hotter than the simulation prediction.

  1. The Kelvin-Helmholtz instability in National Ignition Facility hohlraums as a source of gold-gas mixing

    Energy Technology Data Exchange (ETDEWEB)

    Vandenboomgaerde, M.; Bonnefille, M.; Gauthier, P. [CEA, DAM, DIF, F-91297 Arpajon (France)

    2016-05-15

    Highly resolved radiation-hydrodynamics FCI2 simulations have been performed to model laser experiments on the National Ignition Facility. In these experiments, cylindrical gas-filled hohlraums with gold walls are driven by a 20 ns laser pulse. For the first time, simulations show the appearance of Kelvin-Helmholtz (KH) vortices at the interface between the expanding wall material and the gas fill. In this paper, we determine the mechanisms which generate this instability: the increase of the gas pressure around the expanding gold plasma leads to the aggregation of an over-dense gold layer simultaneously with shear flows. At the surface of this layer, all the conditions are met for a KH instability to grow. Later on, as the interface decelerates, the Rayleigh-Taylor instability also comes into play. A potential scenario for the generation of a mixing zone at the gold-gas interface due to the KH instability is presented. Our estimates of the Reynolds number and the plasma diffusion width at the interface support the possibility of such a mix. The key role of the first nanosecond of the laser pulse in the instability occurrence is also underlined.

  2. Why relevance theory is relevant for lexicography

    DEFF Research Database (Denmark)

    Bothma, Theo; Tarp, Sven

    2014-01-01

    This article starts by providing a brief summary of relevance theory in information science in relation to the function theory of lexicography, explaining the different types of relevance, viz. objective system relevance and the subjective types of relevance, i.e. topical, cognitive, situational...... that is very important for lexicography as well as for information science, viz. functional relevance. Since all lexicographic work is ultimately aimed at satisfying users’ information needs, the article then discusses why the lexicographer should take note of all these types of relevance when planning a new...... dictionary project, identifying new tasks and responsibilities of the modern lexicographer. The article furthermore discusses how relevance theory impacts on teaching dictionary culture and reference skills. By integrating insights from lexicography and information science, the article contributes to new...

  3. Characterization of the neutron flux in the Hohlraum of the thermal column of the TRIGA Mark III reactor of the ININ

    International Nuclear Information System (INIS)

    Delfin L, A.; Palacios, J.C.; Alonso, G.

    2006-01-01

    Knowing the magnitude of the neutron flux in the reactor irradiation facilities, is so much importance for the operation of the same one, like for the investigation developing. Particularly, knowing with certain precision the spectrum and the neutron flux in the different positions of irradiation of a reactor, it is essential for the evaluation of the results obtained for a certain irradiation experiment. The TRIGA Mark III reactor account with irradiation facilities designed to carry out experimentation, where the reactor is used like an intense neutron source and gamma radiation, what allows to make irradiations of samples or equipment in radiation fields with components and diverse levels in the different facilities, one of these irradiation facilities is the Thermal Column where the Hohlraum is. In this work it was carried out a characterization of the neutron flux inside the 'Hohlraum' of the irradiation facility Thermal Column of the TRIGA Mark III reactor of the Nuclear Center of Mexico to 1 MW of power. It was determined the sub cadmic neutron flux and the epi cadmic by means of the neutron activation technique of thin sheets of gold. The maps of the distribution of the neutron flux for both energy groups in three different positions inside the 'Hohlraum' are presented, these maps were obtained by means of the irradiation of undressed thin activation sheets of gold and covered with cadmium in arrangements of 10 x 12, located parallel to 11.5 cm, 40.5 cm and 70.5 cm to the internal wall of graphite of the installation in inverse address to the position of the reactor core. Starting from the obtained values of neutron flux it was found that, for the same position of the surface of irradiation of the experimental arrangement, the relative differences among the values of neutron flux can be of 80%, and that the differences among different positions of the irradiation surfaces can vary until in a one order of magnitude. (Author)

  4. The association of 83 plasma proteins with CHD mortality, BMI, HDL-, and total-cholesterol in men: Applying multivariate statistics to identify proteins with prognostic value and biological relevance

    NARCIS (Netherlands)

    Geert Heidema, A.; Thissen, U.; Boer, J.M.A.; Bouwman, F.G.; Feskens, E.J.M.; Mariman, E.C.M.

    2009-01-01

    In this study, we applied the multivariate statistical tool Partial Least Squares (PLS) to analyze the relative importance of 83 plasma proteins in relation to coronary heart disease (CHD) mortality and the intermediate end points body mass index, HDL-cholesterol and total cholesterol. From a Dutch

  5. Deep learning relevance

    DEFF Research Database (Denmark)

    Lioma, Christina; Larsen, Birger; Petersen, Casper

    2016-01-01

    train a Recurrent Neural Network (RNN) on existing relevant information to that query. We then use the RNN to "deep learn" a single, synthetic, and we assume, relevant document for that query. We design a crowdsourcing experiment to assess how relevant the "deep learned" document is, compared...... to existing relevant documents. Users are shown a query and four wordclouds (of three existing relevant documents and our deep learned synthetic document). The synthetic document is ranked on average most relevant of all....

  6. The Personal Relevance of the Social Studies.

    Science.gov (United States)

    VanSickle, Ronald L.

    1990-01-01

    Conceptualizes a personal-relevance framework derived from Ronald L. VanSickle's five areas of life integrated with four general motivating goals from Abraham Maslow's hierarchy of needs and Richard and Patricia Schmuck's social motivation theory. Illustrates ways to apply the personal relevance framework to make social studies more relevant to…

  7. The association of 83 plasma proteins with CHD mortality, BMI, HDL-, and total-cholesterol in men: applying multivariate statistics to identify proteins with prognostic value and biological relevance.

    Science.gov (United States)

    Heidema, A Geert; Thissen, Uwe; Boer, Jolanda M A; Bouwman, Freek G; Feskens, Edith J M; Mariman, Edwin C M

    2009-06-01

    In this study, we applied the multivariate statistical tool Partial Least Squares (PLS) to analyze the relative importance of 83 plasma proteins in relation to coronary heart disease (CHD) mortality and the intermediate end points body mass index, HDL-cholesterol and total cholesterol. From a Dutch monitoring project for cardiovascular disease risk factors, men who died of CHD between initial participation (1987-1991) and end of follow-up (January 1, 2000) (N = 44) and matched controls (N = 44) were selected. Baseline plasma concentrations of proteins were measured by a multiplex immunoassay. With the use of PLS, we identified 15 proteins with prognostic value for CHD mortality and sets of proteins associated with the intermediate end points. Subsequently, sets of proteins and intermediate end points were analyzed together by Principal Components Analysis, indicating that proteins involved in inflammation explained most of the variance, followed by proteins involved in metabolism and proteins associated with total-C. This study is one of the first in which the association of a large number of plasma proteins with CHD mortality and intermediate end points is investigated by applying multivariate statistics, providing insight in the relationships among proteins, intermediate end points and CHD mortality, and a set of proteins with prognostic value.

  8. Rayleigh-Taylor instabilities in indirect laser drive with rugby-shaped hohlraums; Experiences d'instabilites Rayleigh-Taylor en attaque indirecte avec des cavites rugby

    Energy Technology Data Exchange (ETDEWEB)

    Casner, A.; Galmiche, D.; Huser, G.; Jadaud, J.P.; Richard, A.; Liberatore, S.; Vandenboomgaerde, M. [CEA Bruyeres-le-Chatel, 91 (France)

    2009-07-01

    The mastering of the development of hydrodynamic instabilities like Rayleigh-Taylor instabilities is an important milestone on the way to perform efficient laser implosions. The complexity of these instabilities implies an experimental validation of the theoretical models and their computer simulations. An experimental platform involving the Omega laser has allowed us to perform indirect drive with rugby-shaped hohlraums. The experiments have validated the growth of 2- and 3-dimensional initial defects as predicted by theory. We have shown that the 3-dimensional defect saturates for an higher amplitude than the 2-dimensional one does. The experiments have been made by using a plastic shell doped with Germanium (CH:Ge). (A.C.)

  9. Hohlraum-driven mid-Z (SiO2) double-shell implosions on the omega laser facility and their scaling to NIF.

    Science.gov (United States)

    Robey, H F; Amendt, P A; Milovich, J L; Park, H-S; Hamza, A V; Bono, M J

    2009-10-02

    High-convergence, hohlraum-driven implosions of double-shell capsules using mid-Z (SiO2) inner shells have been performed on the OMEGA laser facility [T. R. Boehly, Opt. Commun. 133, 495 (1997)]. These experiments provide an essential extension of the results of previous low-Z (CH) double-shell implosions [P. A. Amendt, Phys. Rev. Lett. 94, 065004 (2005)] to materials of higher density and atomic number. Analytic modeling, supported by highly resolved 2D numerical simulations, is used to account for the yield degradation due to interfacial atomic mixing. This extended experimental database from OMEGA enables a validation of the mix model, and provides a means for quantitatively assessing the prospects for high-Z double-shell implosions on the National Ignition Facility [Paisner, Laser Focus World 30, 75 (1994)].

  10. Exploring Educational Quality and Relevance through Integrating ...

    African Journals Online (AJOL)

    Exploring Educational Quality and Relevance through Integrating Environmental and Social Issues in Science Education. ... However, the new contextualised concept of learning and teaching was applied only to one of them. A post-test was ...

  11. Applied anatomy of the lingual nerve: relevance to dental anaesthesia.

    Science.gov (United States)

    Tan, Vui Leng; Andrawos, Alice; Ghabriel, Mounir N; Townsend, Grant C

    2014-03-01

    (1) to classify the external morphology of the lingual nerve and investigate any relationship between its external and internal morphology, (2) to explore the fascicular structure, nerve tissue density and capillary density of the lingual nerve, and (3) to provide an anatomical explanation as to why adverse clinical outcomes more commonly affect the lingual nerve following local dental anaesthesia. Where possible, comparisons were made between the lingual and inferior alveolar nerves. The lingual and inferior alveolar nerves were examined in 23 hemi-sectioned heads macroscopically and microscopically 2mm above the lingula. The lingual nerve was also examined in the regions of the third and second molars. Specimens underwent histological processing and staining with Haematoxylin & Eosin, Masson's Trichrome, anti-GLUT-1 and anti-CD 34. The lingual nerve became flatter as it traversed through the pterygomandibular space. There was an increase in the connective tissue and a decrease in nerve tissue density along the lingual nerve (p<0.001). At 2mm above the lingula, the lingual nerve was uni-fascicular in 39% of cases, whilst the inferior alveolar nerve consistently had more fascicles (p<0.001). The lingual nerve fascicles had thicker perineurium but the endoneurial vascular density was not significantly different in the two nerves. The greater susceptibility of lingual nerve dysfunction during inferior alveolar nerve blocks may be due to its uni-fascicular structure and the thicker perineurium, leading to increased endoneurial pressure and involvement of all axons if oedema or haemorrhage occurs due to trauma. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Repository-relevant testing applied to the Yucca Mountain Project

    International Nuclear Information System (INIS)

    Bates, J.K.; Gerding, T.J.; Veleckis, E.

    1989-04-01

    A repository environment poses a challenge to developing a testing program because of the diverse nature of conditions that may exist at a given time during the life of the repository. A starting point is to identify whether any potential waste-water contact modes are particularly deleterious to the waste form performance, and whether any interactions between materials present in the waste package environment need to be accounted for during modeling the waste form reaction. The Unsaturated Test method in one approach that has been developed by the Yucca Mountain Project (YMP) to investigate the above issues, and a description of results that have been obtained during the testing of glass and unirradiated UO 2 are the subject of this report. 10 refs., 7 figs., 4 tabs

  13. Repository relevant testing applied to the Yucca Mountain Project

    International Nuclear Information System (INIS)

    Bates, J.K.; Woodland, A.B.; Wronkiewicz, D.J.; Cunnane, J.C.

    1990-10-01

    The tuff beds of Yucca Mountain, Nevada, are currently being investigated as a site for the disposal of high-level nuclear waste in an underground repository. If this site is found suitable, the repository would be located in the unsaturated zone above the water table, and a description of the site and the methodology of assessing the performance of the repository are described in the Site Characterization Plan (SCP). While many factors are accounted for during performance assessment, an important input parameter is the degradation behavior of the waste forms, which may be either spent fuel or reprocessed waste contained in a borosilicate glass matrix. To develop the necessary waste form degradation input, the waste package environment needs to be identified. This environment will change as the waste decays and also is a function of the repository design which has not yet been finalized. At the present time, an exact description of the waste package environment is not available. The SCP does provide an initial description of conditions that can be used to guide waste form evaluation. However, considerable uncertainty exists concerning the conditions under which waste form degradation and radionuclide release may occur after the waste package containment barriers are finally breached. The release conditions that are considered to be plausible include (1) a open-quotes bathtubclose quotes condition in which the waste becomes fully or partially submerged in water that enters the breached container and accumulates to fill the container up to the level of the breach opening, (2) a open-quotes wet dripclose quotes or open-quotes trickle throughclose quotes condition in which the waste form is exposed to dripping water that enters through the top and exits the bottom of a container with multiple holes, and (3) a open-quotes dryclose quotes condition in which the waste form is exposed to a humid air environment

  14. Hohlraum targets for HIDIF

    International Nuclear Information System (INIS)

    Ramis, R.; Ramirez, J.; Meyer-ter-Vehn, J.

    2000-01-01

    An optimized high gain IFE indirect target design is presented. Beam parameters (5 MJ of 5 GeV Bi + ions in 10-20 ns and focal spot of 3 mm radius) are in agreement to the ones considered recently for the European Study Group on Heavy Ion Driven Inertial Fusion (HIDIF). The energy yield is close to 530 MJ, giving a large enough gain appropriate for industrial energy production. Numerical and analytical modeling are described and discussed. (authors)

  15. Applied physics

    International Nuclear Information System (INIS)

    Anon.

    1980-01-01

    The Physics Division research program that is dedicated primarily to applied research goals involves the interaction of energetic particles with solids. This applied research is carried out in conjunction with the basic research studies from which it evolved

  16. Making Deferred Taxes Relevant

    NARCIS (Netherlands)

    Brouwer, Arjan; Naarding, Ewout

    2018-01-01

    We analyse the conceptual problems in current accounting for deferred taxes and provide solutions derived from the literature in order to make International Financial Reporting Standards (IFRS) deferred tax numbers value-relevant. In our view, the empirical results concerning the value relevance of

  17. Culturally Relevant Cyberbullying Prevention

    OpenAIRE

    Phillips, Gregory John

    2017-01-01

    In this action research study, I, along with a student intervention committee of 14 members, developed a cyberbullying intervention for a large urban high school on the west coast. This high school contained a predominantly African American student population. I aimed to discover culturally relevant cyberbullying prevention strategies for African American students. The intervention committee selected video safety messages featuring African American actors as the most culturally relevant cyber...

  18. Applied Electromagnetics

    Energy Technology Data Exchange (ETDEWEB)

    Yamashita, H; Marinova, I; Cingoski, V [eds.

    2002-07-01

    These proceedings contain papers relating to the 3rd Japanese-Bulgarian-Macedonian Joint Seminar on Applied Electromagnetics. Included are the following groups: Numerical Methods I; Electrical and Mechanical System Analysis and Simulations; Inverse Problems and Optimizations; Software Methodology; Numerical Methods II; Applied Electromagnetics.

  19. Applied Electromagnetics

    International Nuclear Information System (INIS)

    Yamashita, H.; Marinova, I.; Cingoski, V.

    2002-01-01

    These proceedings contain papers relating to the 3rd Japanese-Bulgarian-Macedonian Joint Seminar on Applied Electromagnetics. Included are the following groups: Numerical Methods I; Electrical and Mechanical System Analysis and Simulations; Inverse Problems and Optimizations; Software Methodology; Numerical Methods II; Applied Electromagnetics

  20. The Limits to Relevance

    Science.gov (United States)

    Averill, M.; Briggle, A.

    2006-12-01

    Science policy and knowledge production lately have taken a pragmatic turn. Funding agencies increasingly are requiring scientists to explain the relevance of their work to society. This stems in part from mounting critiques of the "linear model" of knowledge production in which scientists operating according to their own interests or disciplinary standards are presumed to automatically produce knowledge that is of relevance outside of their narrow communities. Many contend that funded scientific research should be linked more directly to societal goals, which implies a shift in the kind of research that will be funded. While both authors support the concept of useful science, we question the exact meaning of "relevance" and the wisdom of allowing it to control research agendas. We hope to contribute to the conversation by thinking more critically about the meaning and limits of the term "relevance" and the trade-offs implicit in a narrow utilitarian approach. The paper will consider which interests tend to be privileged by an emphasis on relevance and address issues such as whose goals ought to be pursued and why, and who gets to decide. We will consider how relevance, narrowly construed, may actually limit the ultimate utility of scientific research. The paper also will reflect on the worthiness of research goals themselves and their relationship to a broader view of what it means to be human and to live in society. Just as there is more to being human than the pragmatic demands of daily life, there is more at issue with knowledge production than finding the most efficient ways to satisfy consumer preferences or fix near-term policy problems. We will conclude by calling for a balanced approach to funding research that addresses society's most pressing needs but also supports innovative research with less immediately apparent application.

  1. Applied superconductivity

    CERN Document Server

    Newhouse, Vernon L

    1975-01-01

    Applied Superconductivity, Volume II, is part of a two-volume series on applied superconductivity. The first volume dealt with electronic applications and radiation detection, and contains a chapter on liquid helium refrigeration. The present volume discusses magnets, electromechanical applications, accelerators, and microwave and rf devices. The book opens with a chapter on high-field superconducting magnets, covering applications and magnet design. Subsequent chapters discuss superconductive machinery such as superconductive bearings and motors; rf superconducting devices; and future prospec

  2. Relevant Subspace Clustering

    DEFF Research Database (Denmark)

    Müller, Emmanuel; Assent, Ira; Günnemann, Stephan

    2009-01-01

    Subspace clustering aims at detecting clusters in any subspace projection of a high dimensional space. As the number of possible subspace projections is exponential in the number of dimensions, the result is often tremendously large. Recent approaches fail to reduce results to relevant subspace...... clusters. Their results are typically highly redundant, i.e. many clusters are detected multiple times in several projections. In this work, we propose a novel model for relevant subspace clustering (RESCU). We present a global optimization which detects the most interesting non-redundant subspace clusters...... achieves top clustering quality while competing approaches show greatly varying performance....

  3. Is Information Still Relevant?

    Science.gov (United States)

    Ma, Lia

    2013-01-01

    Introduction: The term "information" in information science does not share the characteristics of those of a nomenclature: it does not bear a generally accepted definition and it does not serve as the bases and assumptions for research studies. As the data deluge has arrived, is the concept of information still relevant for information…

  4. Applied mathematics

    CERN Document Server

    Logan, J David

    2013-01-01

    Praise for the Third Edition"Future mathematicians, scientists, and engineers should find the book to be an excellent introductory text for coursework or self-study as well as worth its shelf space for reference." -MAA Reviews Applied Mathematics, Fourth Edition is a thoroughly updated and revised edition on the applications of modeling and analyzing natural, social, and technological processes. The book covers a wide range of key topics in mathematical methods and modeling and highlights the connections between mathematics and the applied and nat

  5. Applied mediation analyses

    DEFF Research Database (Denmark)

    Lange, Theis; Hansen, Kim Wadt; Sørensen, Rikke

    2017-01-01

    In recent years, mediation analysis has emerged as a powerful tool to disentangle causal pathways from an exposure/treatment to clinically relevant outcomes. Mediation analysis has been applied in scientific fields as diverse as labour market relations and randomized clinical trials of heart...... disease treatments. In parallel to these applications, the underlying mathematical theory and computer tools have been refined. This combined review and tutorial will introduce the reader to modern mediation analysis including: the mathematical framework; required assumptions; and software implementation...

  6. Cryogenic tritium-hydrogen-deuterium and deuterium-tritium layer implosions with high density carbon ablators in near-vacuum hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Meezan, N. B., E-mail: meezan1@llnl.gov; Hopkins, L. F. Berzak; Pape, S. Le; Divol, L.; MacKinnon, A. J.; Döppner, T.; Ho, D. D.; Jones, O. S.; Khan, S. F.; Ma, T.; Milovich, J. L.; Pak, A. E.; Ross, J. S.; Thomas, C. A.; Benedetti, L. R.; Bradley, D. K.; Celliers, P. M.; Clark, D. S.; Field, J. E.; Haan, S. W. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808 (United States); and others

    2015-06-15

    High Density Carbon (or diamond) is a promising ablator material for use in near-vacuum hohlraums, as its high density allows for ignition designs with laser pulse durations of <10 ns. A series of Inertial Confinement Fusion (ICF) experiments in 2013 on the National Ignition Facility [Moses et al., Phys. Plasmas 16, 041006 (2009)] culminated in a deuterium-tritium (DT) layered implosion driven by a 6.8 ns, 2-shock laser pulse. This paper describes these experiments and comparisons with ICF design code simulations. Backlit radiography of a tritium-hydrogen-deuterium (THD) layered capsule demonstrated an ablator implosion velocity of 385 km/s with a slightly oblate hot spot shape. Other diagnostics suggested an asymmetric compressed fuel layer. A streak camera-based hot spot self-emission diagnostic (SPIDER) showed a double-peaked history of the capsule self-emission. Simulations suggest that this is a signature of low quality hot spot formation. Changes to the laser pulse and pointing for a subsequent DT implosion resulted in a higher temperature, prolate hot spot and a thermonuclear yield of 1.8 × 10{sup 15} neutrons, 40% of the 1D simulated yield.

  7. Cryogenic tritium-hydrogen-deuterium and deuterium-tritium layer implosions with high density carbon ablators in near-vacuum hohlraums

    International Nuclear Information System (INIS)

    Meezan, N. B.; Hopkins, L. F. Berzak; Pape, S. Le; Divol, L.; MacKinnon, A. J.; Döppner, T.; Ho, D. D.; Jones, O. S.; Khan, S. F.; Ma, T.; Milovich, J. L.; Pak, A. E.; Ross, J. S.; Thomas, C. A.; Benedetti, L. R.; Bradley, D. K.; Celliers, P. M.; Clark, D. S.; Field, J. E.; Haan, S. W.

    2015-01-01

    High Density Carbon (or diamond) is a promising ablator material for use in near-vacuum hohlraums, as its high density allows for ignition designs with laser pulse durations of <10 ns. A series of Inertial Confinement Fusion (ICF) experiments in 2013 on the National Ignition Facility [Moses et al., Phys. Plasmas 16, 041006 (2009)] culminated in a deuterium-tritium (DT) layered implosion driven by a 6.8 ns, 2-shock laser pulse. This paper describes these experiments and comparisons with ICF design code simulations. Backlit radiography of a tritium-hydrogen-deuterium (THD) layered capsule demonstrated an ablator implosion velocity of 385 km/s with a slightly oblate hot spot shape. Other diagnostics suggested an asymmetric compressed fuel layer. A streak camera-based hot spot self-emission diagnostic (SPIDER) showed a double-peaked history of the capsule self-emission. Simulations suggest that this is a signature of low quality hot spot formation. Changes to the laser pulse and pointing for a subsequent DT implosion resulted in a higher temperature, prolate hot spot and a thermonuclear yield of 1.8 × 10 15 neutrons, 40% of the 1D simulated yield

  8. Applied Enzymology.

    Science.gov (United States)

    Manoharan, Asha; Dreisbach, Joseph H.

    1988-01-01

    Describes some examples of chemical and industrial applications of enzymes. Includes a background, a discussion of structure and reactivity, enzymes as therapeutic agents, enzyme replacement, enzymes used in diagnosis, industrial applications of enzymes, and immobilizing enzymes. Concludes that applied enzymology is an important factor in…

  9. Clinical Relevance of Adipokines

    Directory of Open Access Journals (Sweden)

    Matthias Blüher

    2012-10-01

    Full Text Available The incidence of obesity has increased dramatically during recent decades. Obesity increases the risk for metabolic and cardiovascular diseases and may therefore contribute to premature death. With increasing fat mass, secretion of adipose tissue derived bioactive molecules (adipokines changes towards a pro-inflammatory, diabetogenic and atherogenic pattern. Adipokines are involved in the regulation of appetite and satiety, energy expenditure, activity, endothelial function, hemostasis, blood pressure, insulin sensitivity, energy metabolism in insulin sensitive tissues, adipogenesis, fat distribution and insulin secretion in pancreatic β-cells. Therefore, adipokines are clinically relevant as biomarkers for fat distribution, adipose tissue function, liver fat content, insulin sensitivity, chronic inflammation and have the potential for future pharmacological treatment strategies for obesity and its related diseases. This review focuses on the clinical relevance of selected adipokines as markers or predictors of obesity related diseases and as potential therapeutic tools or targets in metabolic and cardiovascular diseases.

  10. Information Needs/Relevance

    OpenAIRE

    Wildemuth, Barbara M.

    2009-01-01

    A user's interaction with a DL is often initiated as the result of the user experiencing an information need of some kind. Aspects of that experience and how it might affect the user's interactions with the DL are discussed in this module. In addition, users continuously make decisions about and evaluations of the materials retrieved from a DL, relative to their information needs. Relevance judgments, and their relationship to the user's information needs, are discussed in this module. Draft

  11. Machine Learning and Applied Linguistics

    OpenAIRE

    Vajjala, Sowmya

    2018-01-01

    This entry introduces the topic of machine learning and provides an overview of its relevance for applied linguistics and language learning. The discussion will focus on giving an introduction to the methods and applications of machine learning in applied linguistics, and will provide references for further study.

  12. Applied dynamics

    CERN Document Server

    Schiehlen, Werner

    2014-01-01

    Applied Dynamics is an important branch of engineering mechanics widely applied to mechanical and automotive engineering, aerospace and biomechanics as well as control engineering and mechatronics. The computational methods presented are based on common fundamentals. For this purpose analytical mechanics turns out to be very useful where D’Alembert’s principle in the Lagrangian formulation proves to be most efficient. The method of multibody systems, finite element systems and continuous systems are treated consistently. Thus, students get a much better understanding of dynamical phenomena, and engineers in design and development departments using computer codes may check the results more easily by choosing models of different complexity for vibration and stress analysis.

  13. Applied optics

    International Nuclear Information System (INIS)

    Orszag, A.; Antonetti, A.

    1988-01-01

    The 1988 progress report, of the Applied Optics laboratory, of the (Polytechnic School, France), is presented. The optical fiber activities are focused on the development of an optical gyrometer, containing a resonance cavity. The following domains are included, in the research program: the infrared laser physics, the laser sources, the semiconductor physics, the multiple-photon ionization and the nonlinear optics. Investigations on the biomedical, the biological and biophysical domains are carried out. The published papers and the congress communications are listed [fr

  14. [Relevant public health enteropathogens].

    Science.gov (United States)

    Riveros, Maribel; Ochoa, Theresa J

    2015-01-01

    Diarrhea remains the third leading cause of death in children under five years, despite recent advances in the management and prevention of this disease. It is caused by multiple pathogens, however, the prevalence of each varies by age group, geographical area and the scenario where cases (community vs hospital) are recorded. The most relevant pathogens in public health are those associated with the highest burden of disease, severity, complications and mortality. In our country, norovirus, Campylobacter and diarrheagenic E. coli are the most prevalent pathogens at the community level in children. In this paper we review the local epidemiology and potential areas of development in five selected pathogens: rotavirus, norovirus, Shiga toxin-producing E. coli (STEC), Shigella and Salmonella. Of these, rotavirus is the most important in the pediatric population and the main agent responsible for child mortality from diarrhea. The introduction of rotavirus vaccination in Peru will have a significant impact on disease burden and mortality from diarrhea. However, surveillance studies are needed to determine the impact of vaccination and changes in the epidemiology of diarrhea in Peru following the introduction of new vaccines, as well as antibiotic resistance surveillance of clinical relevant bacteria.

  15. Bradford's Law and Its Relevance to Researchers

    Science.gov (United States)

    Shenton, Andrew K.; Hay-Gibson, Naomi V.

    2009-01-01

    Bradford's Law has been the subject of much discussion and analysis in library and information science since its formulation in the 1930s and remains frequently debated to this day. It has been applied to various practices within the discipline, especially with regard to collection development, but its relevance to researchers and the potential it…

  16. Applied geodesy

    International Nuclear Information System (INIS)

    Turner, S.

    1987-01-01

    This volume is based on the proceedings of the CERN Accelerator School's course on Applied Geodesy for Particle Accelerators held in April 1986. The purpose was to record and disseminate the knowledge gained in recent years on the geodesy of accelerators and other large systems. The latest methods for positioning equipment to sub-millimetric accuracy in deep underground tunnels several tens of kilometers long are described, as well as such sophisticated techniques as the Navstar Global Positioning System and the Terrameter. Automation of better known instruments such as the gyroscope and Distinvar is also treated along with the highly evolved treatment of components in a modern accelerator. Use of the methods described can be of great benefit in many areas of research and industrial geodesy such as surveying, nautical and aeronautical engineering, astronomical radio-interferometry, metrology of large components, deformation studies, etc

  17. Applied mathematics

    International Nuclear Information System (INIS)

    Nedelec, J.C.

    1988-01-01

    The 1988 progress report of the Applied Mathematics center (Polytechnic School, France), is presented. The research fields of the Center are the scientific calculus, the probabilities and statistics and the video image synthesis. The research topics developed are: the analysis of numerical methods, the mathematical analysis of the physics and mechanics fundamental models, the numerical solution of complex models related to the industrial problems, the stochastic calculus and the brownian movement, the stochastic partial differential equations, the identification of the adaptive filtering parameters, the discrete element systems, statistics, the stochastic control and the development, the image synthesis techniques for education and research programs. The published papers, the congress communications and the thesis are listed [fr

  18. Has Financial Statement Information become Less Relevant?

    DEFF Research Database (Denmark)

    Thinggaard, Frank; Damkier, Jesper

    This paper presents insights into the question of whether accounting information based on the EU’s Accounting Directives has become less value-relevant to investors over time. The study is based on a research design first used by Francis and Schipper (1999), where value-relevance is measured......? The sample is based on non-financial companies listed on the Copenhagen Stock Exchange in the period 1984-2002. Our analyses show that all the applied accounting measures are value-relevant as investment strategies based on the information earn positive market-adjusted returns in our sample period....... The results provide some indication of a decline in the value-relevance of earnings information in the 1984-2001 period, and mixed, but not statistically reliable, evidence for accounting measures where book value information and asset values are also extracted from financial statements. The results seem...

  19. Other relevant biological papers

    International Nuclear Information System (INIS)

    Shimizu, M.

    1989-01-01

    A considerable number of CRESP-relevant papers concerning deep-sea biology and radioecology have been published. It is the purpose of this study to call attention to them. They fall into three general categories. The first is papers of general interest. They are mentioned only briefly, and include text references to the global bibliography at the end of the volume. The second are papers that are not only mentioned and referenced, but for various reasons are described in abstract form. The last is a list of papers compiled by H.S.J. Roe specifically for this volume. They are listed in bibliographic form, and are also included in the global bibliography at the end of the volume

  20. Applying radiation

    International Nuclear Information System (INIS)

    Mallozzi, P.J.; Epstein, H.M.; Jung, R.G.; Applebaum, D.C.; Fairand, B.P.; Gallagher, W.J.; Uecker, R.L.; Muckerheide, M.C.

    1979-01-01

    The invention discloses a method and apparatus for applying radiation by producing X-rays of a selected spectrum and intensity and directing them to a desired location. Radiant energy is directed from a laser onto a target to produce such X-rays at the target, which is so positioned adjacent to the desired location as to emit the X-rays toward the desired location; or such X-rays are produced in a region away from the desired location, and are channeled to the desired location. The radiant energy directing means may be shaped (as with bends; adjustable, if desired) to circumvent any obstruction between the laser and the target. Similarly, the X-ray channeling means may be shaped (as with fixed or adjustable bends) to circumvent any obstruction between the region where the X-rays are produced and the desired location. For producing a radiograph in a living organism the X-rays are provided in a short pulse to avoid any blurring of the radiograph from movement of or in the organism. For altering tissue in a living organism the selected spectrum and intensity are such as to affect substantially the tissue in a preselected volume without injuring nearby tissue. Typically, the selected spectrum comprises the range of about 0.1 to 100 keV, and the intensity is selected to provide about 100 to 1000 rads at the desired location. The X-rays may be produced by stimulated emission thereof, typically in a single direction

  1. User perspectives on relevance criteria

    DEFF Research Database (Denmark)

    Maglaughlin, Kelly L.; Sonnenwald, Diane H.

    2002-01-01

    , partially relevant, or not relevant to their information need; and explained their decisions in an interview. Analysis revealed 29 criteria, discussed positively and negatively, that were used by the participants when selecting passages that contributed or detracted from a document's relevance......This study investigates the use of criteria to assess relevant, partially relevant, and not-relevant documents. Study participants identified passages within 20 document representations that they used to make relevance judgments; judged each document representation as a whole to be relevant...... matter, thought catalyst), full text (e.g., audience, novelty, type, possible content, utility), journal/publisher (e.g., novelty, main focus, perceived quality), and personal (e.g., competition, time requirements). Results further indicate that multiple criteria are used when making relevant, partially...

  2. Relevant Scatterers Characterization in SAR Images

    Science.gov (United States)

    Chaabouni, Houda; Datcu, Mihai

    2006-11-01

    Recognizing scenes in a single look meter resolution Synthetic Aperture Radar (SAR) images, requires the capability to identify relevant signal signatures in condition of variable image acquisition geometry, arbitrary objects poses and configurations. Among the methods to detect relevant scatterers in SAR images, we can mention the internal coherence. The SAR spectrum splitted in azimuth generates a series of images which preserve high coherence only for particular object scattering. The detection of relevant scatterers can be done by correlation study or Independent Component Analysis (ICA) methods. The present article deals with the state of the art for SAR internal correlation analysis and proposes further extensions using elements of inference based on information theory applied to complex valued signals. The set of azimuth looks images is analyzed using mutual information measures and an equivalent channel capacity is derived. The localization of the "target" requires analysis in a small image window, thus resulting in imprecise estimation of the second order statistics of the signal. For a better precision, a Hausdorff measure is introduced. The method is applied to detect and characterize relevant objects in urban areas.

  3. EOG feature relevance determination for microsleep detection

    OpenAIRE

    Golz Martin; Wollner Sebastian; Sommer David; Schnieder Sebastian

    2017-01-01

    Automatic relevance determination (ARD) was applied to two-channel EOG recordings for microsleep event (MSE) recognition. 10 s immediately before MSE and also before counterexamples of fatigued, but attentive driving were analysed. Two type of signal features were extracted: the maximum cross correlation (MaxCC) and logarithmic power spectral densities (PSD) averaged in spectral bands of 0.5 Hz width ranging between 0 and 8 Hz. Generalised learn-ing vector quantisation (GRLVQ) was used as ARD...

  4. Decree of the State Office for Nuclear Safety no. 146/1997 specifying nuclear safety-related activities and activities of special radiation protection relevance, requirements for qualification and professional education and training, procedures to examine special professional competence and to grant licences to selected personnel, and the format of documentation to be submitted when applying for selected personnel training licence

    International Nuclear Information System (INIS)

    Egermaier, J.

    2001-01-01

    The Decree is reproduced in the form of facsimile of the relevant pages of the official Collection of Laws of the Czech Republic, and accompanied by a commentary highlighting the past legislative developments and some aspects of this new document. (P.A.)

  5. Applied matrix algebra in the statistical sciences

    CERN Document Server

    Basilevsky, Alexander

    2005-01-01

    This comprehensive text offers teachings relevant to both applied and theoretical branches of matrix algebra and provides a bridge between linear algebra and statistical models. Appropriate for advanced undergraduate and graduate students. 1983 edition.

  6. Laser parametric instability experiments of a 3ω, 15 kJ, 6-ns laser pulse in gas-filled hohlraums at the Ligne d'Intégration Laser facility

    Energy Technology Data Exchange (ETDEWEB)

    Rousseaux, C.; Huser, G.; Loiseau, P.; Casanova, M.; Alozy, E.; Villette, B.; Wrobel, R. [Commissariat à l' Energie Atomique, DAM, DIF, F-91297 Arpajon (France); Henry, O.; Raffestin, D. [Commissariat à l' Energie Atomique, DAM, CESTA, F-33114 Le Barp (France)

    2015-02-15

    Experimental investigation of stimulated Raman (SRS) and Brillouin (SBS) scattering have been obtained at the Ligne-d'Intégration-Laser facility (LIL, CEA-Cesta, France). The parametric instabilities (LPI) are driven by firing four laser beamlets (one quad) into millimeter size, gas-filled hohlraum targets. A quad delivers energy on target of 15 kJ at 3ω in a 6-ns shaped laser pulse. The quad is focused by means of 3ω gratings and is optically smoothed with a kinoform phase plate and with smoothing by spectral dispersion-like 2 GHz and/or 14 GHz laser bandwidth. Open- and closed-geometry hohlraums have been used, all being filled with 1-atm, neo-pentane (C{sub 5}H{sub 12}) gas. For SRS and SBS studies, the light backscattered into the focusing optics is analyzed with spectral and time resolutions. Near-backscattered light at 3ω and transmitted light at 3ω are also monitored in the open geometry case. Depending on the target geometry (plasma length and hydrodynamic evolution of the plasma), it is shown that, at maximum laser intensity about 9 × 10{sup 14} W/cm{sup 2}, Raman reflectivity noticeably increases up to 30% in 4-mm long plasmas while SBS stays below 10%. Consequently, laser transmission through long plasmas drops to about 10% of incident energy. Adding 14 GHz bandwidth to the laser always reduces LPI reflectivities, although this reduction is not dramatic.

  7. Profiles of Dialogue for Relevance

    Directory of Open Access Journals (Sweden)

    Douglas Walton

    2016-12-01

    Full Text Available This paper uses argument diagrams, argumentation schemes, and some tools from formal argumentation systems developed in artificial intelligence to build a graph-theoretic model of relevance shown to be applicable (with some extensions as a practical method for helping a third party judge issues of relevance or irrelevance of an argument in real examples. Examples used to illustrate how the method works are drawn from disputes about relevance in natural language discourse, including a criminal trial and a parliamentary debate.

  8. Relevance theory: pragmatics and cognition.

    Science.gov (United States)

    Wearing, Catherine J

    2015-01-01

    Relevance Theory is a cognitively oriented theory of pragmatics, i.e., a theory of language use. It builds on the seminal work of H.P. Grice(1) to develop a pragmatic theory which is at once philosophically sensitive and empirically plausible (in both psychological and evolutionary terms). This entry reviews the central commitments and chief contributions of Relevance Theory, including its Gricean commitment to the centrality of intention-reading and inference in communication; the cognitively grounded notion of relevance which provides the mechanism for explaining pragmatic interpretation as an intention-driven, inferential process; and several key applications of the theory (lexical pragmatics, metaphor and irony, procedural meaning). Relevance Theory is an important contribution to our understanding of the pragmatics of communication. © 2014 John Wiley & Sons, Ltd.

  9. Clinical relevance in anesthesia journals

    DEFF Research Database (Denmark)

    Lauritsen, Jakob; Møller, Ann M

    2006-01-01

    The purpose of this review is to present the latest knowledge and research on the definition and distribution of clinically relevant articles in anesthesia journals. It will also discuss the importance of the chosen methodology and outcome of articles.......The purpose of this review is to present the latest knowledge and research on the definition and distribution of clinically relevant articles in anesthesia journals. It will also discuss the importance of the chosen methodology and outcome of articles....

  10. Enhancing Ignition Probability and Fusion Yield in NIF Indirect Drive Targets with Applied Magnetic Fields

    Science.gov (United States)

    Perkins, L. John; Logan, B. Grant; Ho, Darwin; Zimmerman, George; Rhodes, Mark; Blackfield, Donald; Hawkins, Steven

    2017-10-01

    Imposed magnetic fields of tens of Tesla that increase to greater than 10 kT (100 MGauss) under capsule compression may relax conditions for ignition and propagating burn in indirect-drive ICF targets. This may allow attainment of ignition, or at least significant fusion energy yields, in presently-performing ICF targets on the National Ignition Facility that today are sub-marginal for thermonuclear burn through adverse hydrodynamic conditions at stagnation. Results of detailed 2D radiation-hydrodynamic-burn simulations applied to NIF capsule implosions with low-mode shape perturbations and residual kinetic energy loss indicate that such compressed fields may increase the probability for ignition through range reduction of fusion alpha particles, suppression of electron heat conduction and stabilization of higher-mode RT instabilities. Optimum initial applied fields are around 50 T. Off-line testing has been performed of a hohlraum coil and pulsed power supply that could be integrated on NIF; axial fields of 58T were obtained. Given the full plasma structure at capsule stagnation may be governed by 3-D resistive MHD, the formation of closed magnetic field lines might further augment ignition prospects. Experiments are now required to assess the potential of applied magnetic fields to NIF ICF ignition and burn. Work performed under auspices of U.S. DOE by LLNL under Contract DE-AC52-07NA27344.

  11. Identifying Relevant Studies in Software Engineering

    DEFF Research Database (Denmark)

    Zhang, He; Ali Babar, Muhammad; Tell, Paolo

    2011-01-01

    Context: Systematic literature review (SLR) has become an important research methodology in software engineering since the introduction of evidence-based software engineering (EBSE) in 2004. One critical step in applying this methodology is to design and execute appropriate and effective search....... Objective: The main objective of the research reported in this paper is to improve the search step of undertaking SLRs in software engineering (SE) by devising and evaluating systematic and practical approaches to identifying relevant studies in SE. Method: We have systematically selected and analytically...

  12. Applied Linguistics: The Challenge of Theory

    Science.gov (United States)

    McNamara, Tim

    2015-01-01

    Language has featured prominently in contemporary social theory, but the relevance of this fact to the concerns of Applied Linguistics, with its necessary orientation to practical issues of language in context, represents an ongoing challenge. This article supports the need for a greater engagement with theory in Applied Linguistics. It considers…

  13. Shippingport: A relevant decommissioning project

    International Nuclear Information System (INIS)

    Crimi, F.P.

    1988-01-01

    Because of Shippingport's low electrical power rating (72 MWe), there has been some misunderstanding on the relevancy of the Shippingport Station Decommissioning Project (SSDP) to a modern 1175 MWe commercial pressurized water reactor (PWR) power station. This paper provides a comparison of the major components of the reactor plant of the 72 MWe Shippingport Atomic Power Station and an 1175 MWe nuclear plant and the relevancy of the Shippingport decommissioning as a demonstration project for the nuclear industry. For the purpose of this comparison, Portland General Electric Company's 1175 MWe Trojan Nuclear Plant at Rainier, Oregon, has been used as the reference nuclear power plant. 2 refs., 2 figs., 1 tab

  14. EOG feature relevance determination for microsleep detection

    Directory of Open Access Journals (Sweden)

    Golz Martin

    2017-09-01

    Full Text Available Automatic relevance determination (ARD was applied to two-channel EOG recordings for microsleep event (MSE recognition. 10 s immediately before MSE and also before counterexamples of fatigued, but attentive driving were analysed. Two type of signal features were extracted: the maximum cross correlation (MaxCC and logarithmic power spectral densities (PSD averaged in spectral bands of 0.5 Hz width ranging between 0 and 8 Hz. Generalised learn-ing vector quantisation (GRLVQ was used as ARD method to show the potential of feature reduction. This is compared to support-vector machines (SVM, in which the feature reduction plays a much smaller role. Cross validation yielded mean normalised relevancies of PSD features in the range of 1.6 – 4.9 % and 1.9 – 10.4 % for horizontal and vertical EOG, respectively. MaxCC relevancies were 0.002 – 0.006 % and 0.002 – 0.06 %, respectively. This shows that PSD features of vertical EOG are indispensable, whereas MaxCC can be neglected. Mean classification accuracies were estimated at 86.6±b 1.3 % and 92.3±b 0.2 % for GRLVQ and SVM, respectively. GRLVQ permits objective feature reduction by inclusion of all processing stages, but is not as accurate as SVM.

  15. EOG feature relevance determination for microsleep detection

    Directory of Open Access Journals (Sweden)

    Golz Martin

    2017-09-01

    Full Text Available Automatic relevance determination (ARD was applied to two-channel EOG recordings for microsleep event (MSE recognition. 10 s immediately before MSE and also before counterexamples of fatigued, but attentive driving were analysed. Two type of signal features were extracted: the maximum cross correlation (MaxCC and logarithmic power spectral densities (PSD averaged in spectral bands of 0.5 Hz width ranging between 0 and 8 Hz. Generalised learn-ing vector quantisation (GRLVQ was used as ARD method to show the potential of feature reduction. This is compared to support-vector machines (SVM, in which the feature reduction plays a much smaller role. Cross validation yielded mean normalised relevancies of PSD features in the range of 1.6 - 4.9 % and 1.9 - 10.4 % for horizontal and vertical EOG, respectively. MaxCC relevancies were 0.002 - 0.006 % and 0.002 - 0.06 %, respectively. This shows that PSD features of vertical EOG are indispensable, whereas MaxCC can be neglected. Mean classification accuracies were estimated at 86.6±b 1.3 % and 92.3±b 0.2 % for GRLVQ and SVM, respec-tively. GRLVQ permits objective feature reduction by inclu-sion of all processing stages, but is not as accurate as SVM.

  16. Applying evolutionary anthropology.

    Science.gov (United States)

    Gibson, Mhairi A; Lawson, David W

    2015-01-01

    Evolutionary anthropology provides a powerful theoretical framework for understanding how both current environments and legacies of past selection shape human behavioral diversity. This integrative and pluralistic field, combining ethnographic, demographic, and sociological methods, has provided new insights into the ultimate forces and proximate pathways that guide human adaptation and variation. Here, we present the argument that evolutionary anthropological studies of human behavior also hold great, largely untapped, potential to guide the design, implementation, and evaluation of social and public health policy. Focusing on the key anthropological themes of reproduction, production, and distribution we highlight classic and recent research demonstrating the value of an evolutionary perspective to improving human well-being. The challenge now comes in transforming relevance into action and, for that, evolutionary behavioral anthropologists will need to forge deeper connections with other applied social scientists and policy-makers. We are hopeful that these developments are underway and that, with the current tide of enthusiasm for evidence-based approaches to policy, evolutionary anthropology is well positioned to make a strong contribution. © 2015 Wiley Periodicals, Inc.

  17. Applying Evolutionary Anthropology

    Science.gov (United States)

    Gibson, Mhairi A; Lawson, David W

    2015-01-01

    Evolutionary anthropology provides a powerful theoretical framework for understanding how both current environments and legacies of past selection shape human behavioral diversity. This integrative and pluralistic field, combining ethnographic, demographic, and sociological methods, has provided new insights into the ultimate forces and proximate pathways that guide human adaptation and variation. Here, we present the argument that evolutionary anthropological studies of human behavior also hold great, largely untapped, potential to guide the design, implementation, and evaluation of social and public health policy. Focusing on the key anthropological themes of reproduction, production, and distribution we highlight classic and recent research demonstrating the value of an evolutionary perspective to improving human well-being. The challenge now comes in transforming relevance into action and, for that, evolutionary behavioral anthropologists will need to forge deeper connections with other applied social scientists and policy-makers. We are hopeful that these developments are underway and that, with the current tide of enthusiasm for evidence-based approaches to policy, evolutionary anthropology is well positioned to make a strong contribution. PMID:25684561

  18. Dramatic lives and relevant becomings

    DEFF Research Database (Denmark)

    Henriksen, Ann-Karina; Miller, Jody

    2012-01-01

    of marginality into positions of relevance. The analysis builds on empirical data from Copenhagen, Denmark, gained through ethnographic fieldwork with the participation of 20 female informants aged 13–22. The theoretical contribution proposes viewing conflicts as multi-linear, multi-causal and non...

  19. Regularization in Matrix Relevance Learning

    NARCIS (Netherlands)

    Schneider, Petra; Bunte, Kerstin; Stiekema, Han; Hammer, Barbara; Villmann, Thomas; Biehl, Michael

    A In this paper, we present a regularization technique to extend recently proposed matrix learning schemes in learning vector quantization (LVQ). These learning algorithms extend the concept of adaptive distance measures in LVQ to the use of relevance matrices. In general, metric learning can

  20. Popularity and Relevance of Science Education and Scientific Literacy

    DEFF Research Database (Denmark)

    Graeber, Wolfgang; Blonder, Ron; Bolte, Claus

    2008-01-01

    A consortium of researchers from 8 European nations has successfully applied to the EU commission for funding the PARSEL (Popularity and Relevance in Science Education for Scientific Literacy) project, which aims at raising the popularity and relevance of science teaching and enhancing students...... of a range of personal and social skills (including cognitive skills associated with investigatory scientific problem solving and socio-scientific decision making) and clarify the relevancy of science education for the 21st century. This symposium will introduce and discuss the project PARSEL ideas within...

  1. The Improved Relevance Voxel Machine

    DEFF Research Database (Denmark)

    Ganz, Melanie; Sabuncu, Mert; Van Leemput, Koen

    The concept of sparse Bayesian learning has received much attention in the machine learning literature as a means of achieving parsimonious representations of features used in regression and classification. It is an important family of algorithms for sparse signal recovery and compressed sensing....... Hence in its current form it is reminiscent of a greedy forward feature selection algorithm. In this report, we aim to solve the problems of the original RVoxM algorithm in the spirit of [7] (FastRVM).We call the new algorithm Improved Relevance Voxel Machine (IRVoxM). Our contributions...... and enables basis selection from overcomplete dictionaries. One of the trailblazers of Bayesian learning is MacKay who already worked on the topic in his PhD thesis in 1992 [1]. Later on Tipping and Bishop developed the concept of sparse Bayesian learning [2, 3] and Tipping published the Relevance Vector...

  2. A Compositional Relevance Model for Adaptive Information Retrieval

    Science.gov (United States)

    Mathe, Nathalie; Chen, James; Lu, Henry, Jr. (Technical Monitor)

    1994-01-01

    There is a growing need for rapid and effective access to information in large electronic documentation systems. Access can be facilitated if information relevant in the current problem solving context can be automatically supplied to the user. This includes information relevant to particular user profiles, tasks being performed, and problems being solved. However most of this knowledge on contextual relevance is not found within the contents of documents, and current hypermedia tools do not provide any easy mechanism to let users add this knowledge to their documents. We propose a compositional relevance network to automatically acquire the context in which previous information was found relevant. The model records information on the relevance of references based on user feedback for specific queries and contexts. It also generalizes such information to derive relevant references for similar queries and contexts. This model lets users filter information by context of relevance, build personalized views of documents over time, and share their views with other users. It also applies to any type of multimedia information. Compared to other approaches, it is less costly and doesn't require any a priori statistical computation, nor an extended training period. It is currently being implemented into the Computer Integrated Documentation system which enables integration of various technical documents in a hypertext framework.

  3. Microdosing: Concept, application and relevance

    Directory of Open Access Journals (Sweden)

    Tushar Tewari

    2010-01-01

    Full Text Available The use of microdose pharmacokinetic studies as an essential tool in drug development is still to catch on. While this approach promises potential cost savings and a quantum leap in efficiencies of the drug development process, major hurdles still need to be overcome before the technique becomes commonplace and part of routine practice. Clear regulations in Europe and the USA have had an enabling effect. The lack of enabling provisions for microdosing studies in Indian regulation, despite low risk and manifest relevance for the local drug development industry, is inconsistent with the country′s aspirations to be among the leaders in pharmaceutical research.

  4. The Relevance of Doctoral Training in Different Labour Markets

    Science.gov (United States)

    Kyvik, Svein; Olsen, Terje Bruen

    2012-01-01

    This study examines the relevance of doctoral training (thesis, coursework and generic skills) for a career in three types of labour market: academia, applied research institutes and industrial laboratories, and non-research workplaces. Data are drawn from a mail survey among PhD holders in Norway. In total, more than 40% of the respondents had…

  5. A principled and cosmopolitan neuroethics: considerations for international relevance

    OpenAIRE

    Shook, John R; Giordano, James

    2014-01-01

    Neuroethics applies cognitive neuroscience for prescribing alterations to conceptions of self and society, and for prescriptively judging the ethical applications of neurotechnologies. Plentiful normative premises are available to ground such prescriptivity, however prescriptive neuroethics may remain fragmented by social conventions, cultural ideologies, and ethical theories. Herein we offer that an objectively principled neuroethics for international relevance requires a new meta-ethics: un...

  6. Biological relevance and synthesis of C-substituted morpholine derivatives

    NARCIS (Netherlands)

    Wijtmans, R.; Vink, M.K.S.; Schoemaker, H.E.; Delft, F.L. van; Blaauw, R.H.; Rutjes, F.P.J.T.

    2004-01-01

    C-Functionalized morpholines are found in a variety of natural products and biologically active compounds, but have also for other reasons been applied in organic synthesis. This review deals with the biological relevance of C-substituted morpholines, their synthesis and important applications in

  7. The missing dimension: the relevance of people's conception of time.

    Science.gov (United States)

    Norgate, Sarah H; Davies, Nigel; Speed, Chris; Cherrett, Tom; Dickinson, Janet

    2014-02-01

    While a timely conceptual innovation for the digital age, the "map" proposed by Bentley et al. would benefit from strengthening through the inclusion of a non-clock-time perspective. In this way, there could be new hypotheses developed which could be applied and tested relevant to more diverse societies, cultures, and individuals.

  8. "To Mediate Relevantly": A Response to James Simpson

    Science.gov (United States)

    Waters, Alan

    2009-01-01

    In Waters (2009), it was contended that, because of its ideological orientation, a good deal of applied linguistics for language teaching (ALLT) fails to "mediate relevantly" between academic and practitioner perspectives. James Simpson's rejoinder to my article (Simpson 2009) attempts to refute its claims. However, in my view, it fails to do so,…

  9. Relevance in the science classroom: A multidimensional analysis

    Science.gov (United States)

    Hartwell, Matthew F.

    While perceived relevance is considered a fundamental component of adaptive learning, the experience of relevance and its conceptual definition have not been well described. The mixed-methods research presented in this dissertation aimed to clarify the conceptual meaning of relevance by focusing on its phenomenological experience from the students' perspective. Following a critical literature review, I propose an identity-based model of perceived relevance that includes three components: a contextual target, an identity target, and a connection type, or lens. An empirical investigation of this model that consisted of two general phases was implemented in four 9th grade-biology classrooms. Participants in Phase 1 (N = 118) completed a series of four open-ended writing activities focused on eliciting perceived personal connections to academic content. Exploratory qualitative content analysis of a 25% random sample of the student responses was used to identify the main meaning-units of the proposed model as well as different dimensions of student relevance perceptions. These meaning-units and dimensions provided the basis for the construction of a conceptual mapping sentence capturing students' perceived relevance, which was then applied in a confirmatory analysis to all other student responses. Participants in Phase 2 (N = 139) completed a closed survey designed based on the mapping sentence to assess their perceived relevance of a biology unit. The survey also included scales assessing other domain-level motivational processes. Exploratory factor analysis and non-metric multidimensional scaling indicated a coherent conceptual structure, which included a primary interpretive relevance dimension. Comparison of the conceptual structure across various groups (randomly-split sample, gender, academic level, domain-general motivational profiles) provided support for its ubiquity and insight into variation in the experience of perceived relevance among students of different

  10. Silk-polypyrrole biocompatible actuator performance under biologically relevant conditions

    Science.gov (United States)

    Hagler, Jo'elen; Peterson, Ben; Murphy, Amanda; Leger, Janelle

    Biocompatible actuators that are capable of controlled movement and can function under biologically relevant conditions are of significant interest in biomedical fields. Previously, we have demonstrated that a composite material of silk biopolymer and the conducting polymer polypyrrole (PPy) can be formed into a bilayer device that can bend under applied voltage. Further, these silk-PPy composites can generate forces comparable to human muscle (>0.1 MPa) making them ideal candidates for interfacing with biological tissues. Here silk-PPy composite films are tested for performance under biologically relevant conditions including exposure to a complex protein serum and biologically relevant temperatures. Free-end bending actuation performance, current response, force generation and, mass degradation were investigated . Preliminary results show that when exposed to proteins and biologically relevant temperatures, these silk-PPy composites show minimal degradation and are able to generate forces and conduct currents comparable to devices tested under standard conditions. NSF.

  11. Other relevant numerical modelling papers

    International Nuclear Information System (INIS)

    Chartier, M.

    1989-01-01

    The ocean modelling is a rapidly evolving science and a large number of results have been published. Several categories of papers are of particular interest for this review: the papers published by the international atomic institutions, such as the NEA (for the CRESP or Subseabed Programs), the IAEA (for example the Safety Series, the Technical Report Series or the TECDOC), and the ICRP, and the papers concerned by more fundamental research, which are published in specific scientific literature. This paper aims to list some of the most relevant publications for the CRESP purposes. It means by no way to be exhaustive, but informative on the incontestable progress recently achieved in that field. One should note that some of these papers are so recent that their final version has not yet been published

  12. Industrial relevance of thermophilic Archaea.

    Science.gov (United States)

    Egorova, Ksenia; Antranikian, Garabed

    2005-12-01

    The dramatic increase of newly isolated extremophilic microorganisms, analysis of their genomes and investigations of their enzymes by academic and industrial laboratories demonstrate the great potential of extremophiles in industrial (white) biotechnology. Enzymes derived from extremophiles (extremozymes) are superior to the traditional catalysts because they can perform industrial processes even under harsh conditions, under which conventional proteins are completely denatured. In particular, enzymes from thermophilic and hyperthermophilic Archaea have industrial relevance. Despite intensive investigations, our knowledge of the structure-function relationships of their enzymes is still limited. Information concerning the molecular properties of their enzymes and genes has to be obtained to be able to understand the mechanisms that are responsible for catalytic activity and stability at the boiling point of water.

  13. The Relevance of Hegel's Logic

    Directory of Open Access Journals (Sweden)

    John W Burbidge

    2007-12-01

    Full Text Available Hegel defines his Logic as the science that thinks about thinking.nbsp; But when we interpret that work as outlining what happens when we reason we are vulnerable to Fregersquo;s charge of psychologism.nbsp; I use Hegelrsquo;s tripartite distinction among understanding, dialectical and speculative reason as operations of pure thought to suggest how thinking can work with objective concepts.nbsp; In the last analysis, however, our ability to move from the subjective contingency of representations and ideas to the pure concepts we think develops from mechanical memory, which separates sign from sense so hat we can focus simply on the latter.nbsp; By becoming aware of the connections that underlie our thinking processes we may be able to both move beyond the abstractions of symbolic logic and clarify what informal logicians call relevance.

  14. 1st Applied Electromagnetic International Conference

    CERN Document Server

    Othman, Mohd; Aziz, Mohamad; Malek, Mohd

    2015-01-01

    In this book, experts from academia and industry present the latest advances in scientific theory relating to applied electromagnetics and examine current and emerging applications particularly within the fields of electronics, communications, and computer technology. The book is based on presentations delivered at APPEIC 2014, the 1st Applied Electromagnetic International Conference, held in Bandung, Indonesia in December 2014. The conference provided an ideal platform for researchers and specialists to deliver both theoretically and practically oriented contributions on a wide range of topics relevant to the theme of nurturing applied electromagnetics for human technology. Many novel aspects were addressed, and the contributions selected for this book highlight the relevance of advances in applied electromagnetics to a variety of industrial engineering problems and identify exciting future directions for research.

  15. 2nd Applied Electromagnetic International Conference

    CERN Document Server

    Sulaiman, Hamzah; Othman, Mohd; Aziz, Mohamad; Malek, Mohd

    2017-01-01

    In this book, experts from academia and industry present the latest advances in scientific theory relating to applied electromagnetics and examine current and emerging applications particularly within the fields of electronics, communications, and computer technology. The book is based on presentations delivered at APPEIC 2015, the 2nd Applied Electromagnetic International Conference, held in Krabi, Thailand in December 2015. The conference provided an ideal platform for researchers and specialists to deliver both theoretically and practically oriented contributions on a wide range of topics relevant to the theme of nurturing applied electromagnetics for human technology. Many novel aspects were addressed, and the contributions selected for this book highlight the relevance of advances in applied electromagnetics to a variety of industrial engineering problems and identify exciting future directions for research.

  16. Essays in Applied Microeconomics

    Science.gov (United States)

    Ge, Qi

    This dissertation consists of three self-contained applied microeconomics essays on topics related to behavioral economics and industrial organization. Chapter 1 studies how sentiment as a result of sports event outcomes affects consumers' tipping behavior in the presence of social norms. I formulate a model of tipping behavior that captures consumer sentiment following a reference-dependent preference framework and empirically test its relevance using the game outcomes of the NBA and the trip and tipping data on New York City taxicabs. While I find that consumers' tipping behavior responds to unexpected wins and losses of their home team, particularly in close game outcomes, I do not find evidence for loss aversion. Coupled with the findings on default tipping, my empirical results on the asymmetric tipping responses suggest that while social norms may dominate loss aversion, affect and surprises can result in freedom on the upside of tipping. Chapter 2 utilizes a novel data source of airline entry and exit announcements and examines how the incumbent airlines adjust quality provisions as a response to their competitors' announcements and the role of timing in such responses. I find no evidence that the incumbents engage in preemptive actions when facing probable entry and exit threats as signaled by the competitors' announcements in either short term or long term. There is, however, evidence supporting their responses to the competitors' realized entry or exit. My empirical findings underscore the role of timing in determining preemptive actions and suggest that previous studies may have overestimated how the incumbent airlines respond to entry threats. Chapter 3, which is collaborated with Benjamin Ho, investigates the habit formation of consumers' thermostat setting behavior, an often implicitly made decision and yet a key determinant of home energy consumption and expenditures. We utilize a high frequency dataset on household thermostat usage and find that

  17. Journal of applied mathematics

    National Research Council Canada - National Science Library

    2001-01-01

    "[The] Journal of Applied Mathematics is a refereed journal devoted to the publication of original research papers and review articles in all areas of applied, computational, and industrial mathematics...

  18. Mesothelioma Applied Research Foundation

    Science.gov (United States)

    ... Foundation Experts Can Answer Your Questions! The Mesothelioma Applied Research Foundation's team of experts is available to answer ... a law firm. Read more about the Mesothelioma Applied Research Foundation . TO GET HELP CALL: (877) End-Meso ...

  19. Applied Energy Program

    Science.gov (United States)

    Science Programs Applied Energy Programs Civilian Nuclear Energy Programs Laboratory Directed Research » Applied Energy Program Applied Energy Program Los Alamos is using its world-class scientific capabilities to enhance national energy security by developing energy sources with limited environmental impact

  20. Vygotsky's Crisis: Argument, context, relevance.

    Science.gov (United States)

    Hyman, Ludmila

    2012-06-01

    Vygotsky's The Historical Significance of the Crisis in Psychology (1926-1927) is an important text in the history and philosophy of psychology that has only become available to scholars in 1982 in Russian, and in 1997 in English. The goal of this paper is to introduce Vygotsky's conception of psychology to a wider audience. I argue that Vygotsky's argument about the "crisis" in psychology and its resolution can be fully understood only in the context of his social and political thinking. Vygotsky shared the enthusiasm, widespread among Russian leftist intelligentsia in the 1920s, that Soviet society had launched an unprecedented social experiment: The socialist revolution opened the way for establishing social conditions that would let the individual flourish. For Vygotsky, this meant that "a new man" of the future would become "the first and only species in biology that would create itself." He envisioned psychology as a science that would serve this humanist teleology. I propose that The Crisis is relevant today insofar as it helps us define a fundamental problem: How can we systematically account for the development of knowledge in psychology? I evaluate how Vygotsky addresses this problem as a historian of the crisis. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Relevance of equilibrium in multifragmentation

    International Nuclear Information System (INIS)

    Furuta, Takuya; Ono, Akira

    2009-01-01

    The relevance of equilibrium in a multifragmentation reaction of very central 40 Ca + 40 Ca collisions at 35 MeV/nucleon is investigated by using simulations of antisymmetrized molecular dynamics (AMD). Two types of ensembles are compared. One is the reaction ensemble of the states at each reaction time t in collision events simulated by AMD, and the other is the equilibrium ensemble prepared by solving the AMD equation of motion for a many-nucleon system confined in a container for a long time. The comparison of the ensembles is performed for the fragment charge distribution and the excitation energies. Our calculations show that there exists an equilibrium ensemble that well reproduces the reaction ensemble at each reaction time t for the investigated period 80≤t≤300 fm/c. However, there are some other observables that show discrepancies between the reaction and equilibrium ensembles. These may be interpreted as dynamical effects in the reaction. The usual static equilibrium at each instant is not realized since any equilibrium ensemble with the same volume as that of the reaction system cannot reproduce the fragment observables

  2. The Master's Thesis in Applied Psychology Training.

    Science.gov (United States)

    Shultz, Kenneth S.; Kottke, Janet L.

    1996-01-01

    Recommends the inclusion of a master's thesis in industrial and organizational psychology programs. Argues that the thesis serves several critical educational purposes and is relevant to applied psychology. Offers suggestions for increasing the relationship between the educational requirement and the professional tasks. (MJP)

  3. The Problem of Probability: An Examination and Refutation of Hjørland’s Relevance Equation

    DEFF Research Database (Denmark)

    Nicolaisen, Jeppe

    2017-01-01

    Introduction. The paper presents a critical examination of Professor Birger Hjørland’s relevance equation: Something (A) is relevant to a task (T) if it increases the likelihood of accomplishing the goal (G), which is implied by T. Method. Two theories of probability logic (the logical theory...... and the intersubjective theory) are briefly reviewed and then applied to Hjørland’s equation. Analysis. Focusing on how these theories warrant the probability assumption makes it possible to detect deficiencies in Hjørland’s equation, based as it is on probability logic. Results. Regardless of the kind of logic applied...... to warrant the probability assumption of Hjørland’s equation, the outcome of using it to determine the relevance of any A to any T is found to have quite bizarre consequences: Either nothing is relevant or everything is relevant. Conclusion. Contrary to Hjørland’s claim that his relevance equation applies...

  4. Statistical significance versus clinical relevance.

    Science.gov (United States)

    van Rijn, Marieke H C; Bech, Anneke; Bouyer, Jean; van den Brand, Jan A J G

    2017-04-01

    In March this year, the American Statistical Association (ASA) posted a statement on the correct use of P-values, in response to a growing concern that the P-value is commonly misused and misinterpreted. We aim to translate these warnings given by the ASA into a language more easily understood by clinicians and researchers without a deep background in statistics. Moreover, we intend to illustrate the limitations of P-values, even when used and interpreted correctly, and bring more attention to the clinical relevance of study findings using two recently reported studies as examples. We argue that P-values are often misinterpreted. A common mistake is saying that P < 0.05 means that the null hypothesis is false, and P ≥0.05 means that the null hypothesis is true. The correct interpretation of a P-value of 0.05 is that if the null hypothesis were indeed true, a similar or more extreme result would occur 5% of the times upon repeating the study in a similar sample. In other words, the P-value informs about the likelihood of the data given the null hypothesis and not the other way around. A possible alternative related to the P-value is the confidence interval (CI). It provides more information on the magnitude of an effect and the imprecision with which that effect was estimated. However, there is no magic bullet to replace P-values and stop erroneous interpretation of scientific results. Scientists and readers alike should make themselves familiar with the correct, nuanced interpretation of statistical tests, P-values and CIs. © The Author 2017. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

  5. Students' perceptions of the relevance of mathematics in engineering

    Science.gov (United States)

    Flegg, Jennifer; Mallet, Dann; Lupton, Mandy

    2012-09-01

    In this article, we report on the findings of an exploratory study into the experience of students as they learn first year engineering mathematics. Here we define engineering as the application of mathematics and sciences to the building and design of projects for the use of society [M. Kirschenman and B. Brenner, Education for Civil Engineering: A Profession of Practice, Leader. Manag. Eng. 10 (2010), p. 54]. Qualitative and quantitative data on students' views of the relevance of their mathematics study to their engineering studies and future careers in engineering was collected. The students described using a range of mathematics techniques (mathematics skills developed, mathematics concepts applied to engineering and skills developed relevant for engineering) for various usages (as a subject of study, a tool for other subjects or a tool for real world problems). We found a number of themes relating to the design of engineering mathematics curriculum emerged from the data. These included the relevance of mathematics within different engineering majors, the relevance of mathematics to future studies, the relevance of learning mathematical rigour and the effectiveness of problem-solving tasks in conveying the relevance of mathematics more effectively than other forms of assessment. We make recommendations for the design of engineering mathematics curriculum based on our findings.

  6. Does relevance matter in academic policy research?

    DEFF Research Database (Denmark)

    Dredge, Dianne

    2015-01-01

    A reflection on whether relevance matters in tourism policy research. A debate among tourism scholars.......A reflection on whether relevance matters in tourism policy research. A debate among tourism scholars....

  7. Advances in Applied Mechanics

    OpenAIRE

    2013-01-01

    Advances in Applied Mechanics draws together recent significant advances in various topics in applied mechanics. Published since 1948, Advances in Applied Mechanics aims to provide authoritative review articles on topics in the mechanical sciences, primarily of interest to scientists and engineers working in the various branches of mechanics, but also of interest to the many who use the results of investigations in mechanics in various application areas, such as aerospace, chemical, civil, en...

  8. Perspectives on Applied Ethics

    OpenAIRE

    2007-01-01

    Applied ethics is a growing, interdisciplinary field dealing with ethical problems in different areas of society. It includes for instance social and political ethics, computer ethics, medical ethics, bioethics, envi-ronmental ethics, business ethics, and it also relates to different forms of professional ethics. From the perspective of ethics, applied ethics is a specialisation in one area of ethics. From the perspective of social practice applying eth-ics is to focus on ethical aspects and ...

  9. Applied Neuroscience Laboratory Complex

    Data.gov (United States)

    Federal Laboratory Consortium — Located at WPAFB, Ohio, the Applied Neuroscience lab researches and develops technologies to optimize Airmen individual and team performance across all AF domains....

  10. Science and the struggle for relevance

    NARCIS (Netherlands)

    Hessels, L.K.|info:eu-repo/dai/nl/304832863

    2010-01-01

    This thesis deals with struggles for relevance of university researchers, their efforts to make their work correspond with ruling standards of relevance and to influence these standards. Its general research question is: How to understand changes in the struggle for relevance of Dutch academic

  11. The Development of Relevance in Information Retrieval

    Directory of Open Access Journals (Sweden)

    Mu-hsuan Huang

    1997-12-01

    Full Text Available This article attempts to investigate the notion of relevance in information retrieval. It discusses various definitions for relevance from historical viewpoints and the characteristics of relevance judgments. Also, it introduces empirical results of important related researches.[Article content in Chinese

  12. Photocatalysis applied to concrete products - Part 3: Practical relevance and modeling of the degradation process

    NARCIS (Netherlands)

    Hunger, M.; Hüsken, G.; Brouwers, H.J.H.

    2009-01-01

    The third and last part of this article series concludes the characterization of influencing factors on the degradation performance illustrated by the influence of pigments. Furthermore, the results of an accelerated durability test carried out on coated samples described in the second part of this

  13. Applying analytical redundancy to safety-relevant data acquisition in nuclear power plant

    International Nuclear Information System (INIS)

    Hengy, D.

    1988-01-01

    The modelling study reported here was carried out for examination and testing of four instrumental fault detection methods within the framwork of a non-linear steam generator model. It is shown that the introduction of a time shift between components of the Kalman filter innovation for generation of the covariance matrix can lead to correspondingly delayed error signals, which adds arguments against the suitability of this method. A main point of interest of the project is the question of whether model non-linearities are necessarily to be taken into account in the filter equations. Two alternative methods have been tested and are suggested. These use robust detection filters or state observers and the Fourier analysis. The results obtained are positive, so that there remain three recommendable methods, although it is not possible to carry out a direct comparison of the methods. (orig./DG) [de

  14. THE RELEVANCE OF LEARNING APPLIED ENGLISH FOR ACADEMICS TO FOSTER PROFESSIONALISM

    Directory of Open Access Journals (Sweden)

    Lubna Algadrie

    2005-01-01

    Full Text Available Academics who are not competent in communication skills, particularly language skills, will develop less compared to those who are. Communication skills in general and language skills in particular will foster professionalism since professionals will spend less time doing and more time managing as experience grows. Professionalism grows from qualities that can be learned and developed as well as information learned and acquired. Negotiating skills will enable them to win deals more readily. Moreover, internet based realms of communications are mostly English speaking creations, which vary in terms of level of formality and choice of words. In this paper the writer shares her experience in materials preparations and a classroom-centered research done on a group of academics of non-English majors who came to ITS Language Centre to improve their English language competence for career development and further studies.

  15. Applying the System Component and Operationally Relevant Evaluation (SCORE) Framework to Evaluate Advanced Military Technologies

    Science.gov (United States)

    2010-03-01

    and charac- terize the actions taken by the soldier (e.g., running, walking, climbing stairs ). Real-time image capture and exchange N The ability of...multimedia information sharing among soldiers in the field, two-way speech translation systems, and autonomous robotic platforms. Key words: Emerging...soldiers in the field, two-way speech translation systems, and autonomous robotic platforms. It has been the foundation for 10 technology evaluations

  16. The relevance of social media as it applies in South Africa to crime prediction

    CSIR Research Space (South Africa)

    Featherstone, Coral

    2013-05-01

    Full Text Available of data gathering, prediction and spotting broader patterns. An assessment is done to determine if South African people are already using Twitter to report crime and to find out what information they are sharing, with the goal of estabishing whether...

  17. Biology relevant to space radiation

    International Nuclear Information System (INIS)

    Fry, R.J.M.

    1996-01-01

    The biological effects of the radiations to which mankind on earth are exposed are becoming known with an increasing degree of detail. This knowledge is the basis of the estimates of risk that, in turn, fosters a comprehensive and evolving radiation protection system. The substantial body of information has been, and is being, applied to questions about the biological effects of radiation is space and the associated risk estimates. The purpose of this paper is not to recount all the biological effect of radiation but to concentrate on those that may occur as a result from exposure to the radiations encountered in space. In general, the biological effects of radiation in space are the same as those on earth. However, the evidence that the effects on certain tissues by the heaviest-charged particles can be interpreted on the basis of our knowledge about other high-LET radiation is equivocal. This specific question will be discussed in greater detail later. It is important to point out the that there are only limited data about the effects on humans of two components of the radiations in space, namely protons and heavy ions. Thus predictions of effects on space crews are based on experimental systems exposed on earth at rates and fluences that are higher than those in space and one the effects of gamma or x rays with estimates of the equivalent doses using quality factors

  18. Essays in applied microeconomics

    NARCIS (Netherlands)

    Bernal Lobato, N.

    2014-01-01

    This thesis consists of three chapters dealing with important topics for the well-being of individuals: retirement, health and happiness. All together are micro studies that deal with policy relevant research questions. The first chapter focuses on whether a pension reform has effects on income

  19. What Is Applied Linguistics?

    Science.gov (United States)

    James, Carl

    1993-01-01

    Ostensive and expository definitions of applied linguistics are assessed. It is suggested that the key to a meaningful definition lies in the dual articulation of applied linguistics: it is an interface between linguistics and practicality. Its role as an "expert system" is suggested. (45 references) (Author/LB)

  20. Applied social geography

    OpenAIRE

    Hilpert, Markus

    2002-01-01

    Applied social geography : management of spatial planning in reflective discourse ; research perspectives towards a ‚Theory of Practice‘. - In: Geografija in njene aplikativne moˆznosti = Prospects of applied geography. - Ljubljana : Oddelek za Geografijo, Filozofska Fakulteta, 2002. S. 29-39. - (Dela / Oddelek za geografijo Filozofske fakultete v Ljubljani ; 18)

  1. What are applied ethics?

    Science.gov (United States)

    Allhoff, Fritz

    2011-03-01

    This paper explores the relationships that various applied ethics bear to each other, both in particular disciplines and more generally. The introductory section lays out the challenge of coming up with such an account and, drawing a parallel with the philosophy of science, offers that applied ethics may either be unified or disunified. The second section develops one simple account through which applied ethics are unified, vis-à-vis ethical theory. However, this is not taken to be a satisfying answer, for reasons explained. In the third section, specific applied ethics are explored: biomedical ethics; business ethics; environmental ethics; and neuroethics. These are chosen not to be comprehensive, but rather for their traditions or other illustrative purposes. The final section draws together the results of the preceding analysis and defends a disunity conception of applied ethics.

  2. Nostalgia's place among self-relevant emotions.

    Science.gov (United States)

    van Tilburg, Wijnand A P; Wildschut, Tim; Sedikides, Constantine

    2017-07-24

    How is nostalgia positioned among self-relevant emotions? We tested, in six studies, which self-relevant emotions are perceived as most similar versus least similar to nostalgia, and what underlies these similarities/differences. We used multidimensional scaling to chart the perceived similarities/differences among self-relevant emotions, resulting in two-dimensional models. The results were revealing. Nostalgia is positioned among self-relevant emotions characterised by positive valence, an approach orientation, and low arousal. Nostalgia most resembles pride and self-compassion, and least resembles embarrassment and shame. Our research pioneered the integration of nostalgia among self-relevant emotions.

  3. Applied computing in medicine and health

    CERN Document Server

    Al-Jumeily, Dhiya; Mallucci, Conor; Oliver, Carol

    2015-01-01

    Applied Computing in Medicine and Health is a comprehensive presentation of on-going investigations into current applied computing challenges and advances, with a focus on a particular class of applications, primarily artificial intelligence methods and techniques in medicine and health. Applied computing is the use of practical computer science knowledge to enable use of the latest technology and techniques in a variety of different fields ranging from business to scientific research. One of the most important and relevant areas in applied computing is the use of artificial intelligence (AI) in health and medicine. Artificial intelligence in health and medicine (AIHM) is assuming the challenge of creating and distributing tools that can support medical doctors and specialists in new endeavors. The material included covers a wide variety of interdisciplinary perspectives concerning the theory and practice of applied computing in medicine, human biology, and health care. Particular attention is given to AI-bas...

  4. Applied Mathematics Seminar 1982

    International Nuclear Information System (INIS)

    1983-01-01

    This report contains the abstracts of the lectures delivered at 1982 Applied Mathematics Seminar of the DPD/LCC/CNPq and Colloquy on Applied Mathematics of LCC/CNPq. The Seminar comprised 36 conferences. Among these, 30 were presented by researchers associated to brazilian institutions, 9 of them to the LCC/CNPq, and the other 6 were given by visiting lecturers according to the following distribution: 4 from the USA, 1 from England and 1 from Venezuela. The 1981 Applied Mathematics Seminar was organized by Leon R. Sinay and Nelson do Valle Silva. The Colloquy on Applied Mathematics was held from october 1982 on, being organized by Ricardo S. Kubrusly and Leon R. Sinay. (Author) [pt

  5. Handbook of Applied Analysis

    CERN Document Server

    Papageorgiou, Nikolaos S

    2009-01-01

    Offers an examination of important theoretical methods and procedures in applied analysis. This book details the important theoretical trends in nonlinear analysis and applications to different fields. It is suitable for those working on nonlinear analysis.

  6. Applying contemporary statistical techniques

    CERN Document Server

    Wilcox, Rand R

    2003-01-01

    Applying Contemporary Statistical Techniques explains why traditional statistical methods are often inadequate or outdated when applied to modern problems. Wilcox demonstrates how new and more powerful techniques address these problems far more effectively, making these modern robust methods understandable, practical, and easily accessible.* Assumes no previous training in statistics * Explains how and why modern statistical methods provide more accurate results than conventional methods* Covers the latest developments on multiple comparisons * Includes recent advanc

  7. Relevance: An Interdisciplinary and Information Science Perspective

    Directory of Open Access Journals (Sweden)

    Howard Greisdorf

    2000-01-01

    Full Text Available Although relevance has represented a key concept in the field of information science for evaluating information retrieval effectiveness, the broader context established by interdisciplinary frameworks could provide greater depth and breadth to on-going research in the field. This work provides an overview of the nature of relevance in the field of information science with a cursory view of how cross-disciplinary approaches to relevance could represent avenues for further investigation into the evaluative characteristics of relevance as a means for enhanced understanding of human information behavior.

  8. Problems of applied geochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Ovchinnikov, L N

    1983-01-01

    The concept of applied geochemistry was introduced for the first time by A. Ye. Fersman. He linked the branched and complicated questions of geochemistry with specific problems of developing the mineral and raw material base of our country. Geochemical prospecting and geochemistry of mineral raw materials are the most important sections of applied geochemistry. This now allows us the right to view applied geochemistry as a sector of science which applies geochemical methodology, set of geochemical methods of analysis, synthesis, geological interpretation of data based on laws governing theoretical geochemistry to the solution of different tasks of geology, petrology, tectonics, stratigraphy, science of minerals and other geological sciences, and also the technology of mineral raw materials, interrelationships of man and nature (ecogeochemistry, technogeochemistry, agrogeochemistry). The main problem of applied geochemistry, geochemistry of ore fields is the prehistory of ore formation. This is especially important for metallogenic and forecasting constructions, for an understanding of the reasons for the development of fields and the detection of laws governing their distribution, their genetic links with the general geological processes and the products of these processes.

  9. Brief report: Inhibitory control of socially relevant stimuli in children with high functioning autism

    NARCIS (Netherlands)

    Geurts, H.M.; Begeer, S.; Stockman, L.

    2009-01-01

    The current study explored whether inhibitory control deficits in high functioning autism (HFA) emerged when socially relevant stimuli were used and whether arousal level affected the performance. A Go/NoGo paradigm, with socially relevant stimuli and varying presentation rates, was applied in 18

  10. Applied chemical engineering thermodynamics

    CERN Document Server

    Tassios, Dimitrios P

    1993-01-01

    Applied Chemical Engineering Thermodynamics provides the undergraduate and graduate student of chemical engineering with the basic knowledge, the methodology and the references he needs to apply it in industrial practice. Thus, in addition to the classical topics of the laws of thermodynamics,pure component and mixture thermodynamic properties as well as phase and chemical equilibria the reader will find: - history of thermodynamics - energy conservation - internmolecular forces and molecular thermodynamics - cubic equations of state - statistical mechanics. A great number of calculated problems with solutions and an appendix with numerous tables of numbers of practical importance are extremely helpful for applied calculations. The computer programs on the included disk help the student to become familiar with the typical methods used in industry for volumetric and vapor-liquid equilibria calculations.

  11. PSYCHOANALYSIS AS APPLIED AESTHETICS.

    Science.gov (United States)

    Richmond, Stephen H

    2016-07-01

    The question of how to place psychoanalysis in relation to science has been debated since the beginning of psychoanalysis and continues to this day. The author argues that psychoanalysis is best viewed as a form of applied art (also termed applied aesthetics) in parallel to medicine as applied science. This postulate draws on a functional definition of modernity as involving the differentiation of the value spheres of science, art, and religion. The validity criteria for each of the value spheres are discussed. Freud is examined, drawing on Habermas, and seen to have erred by claiming that the psychoanalytic method is a form of science. Implications for clinical and metapsychological issues in psychoanalysis are discussed. © 2016 The Psychoanalytic Quarterly, Inc.

  12. Earnings Management, Value Relevance Of Earnings and Book Value of Equity

    OpenAIRE

    Subekti, Imam

    2013-01-01

    Previous studies examining relationship between earnings management and value relevance of accounting information show that earnings management decrease value relevance of accounting information. Generally, the studies apply accruals earnings management. In contrast, the present study applies integrated earnings management proxies i.e. real and accruals earnings manage-ment. Real earnings management proxies are measured by abnormal cash flow of operation, ab-normal production cost, and abnorm...

  13. Applied peritoneal anatomy

    International Nuclear Information System (INIS)

    Patel, R.R.; Planche, K.

    2013-01-01

    The peritoneal cavity is a complex anatomical structure with multiple attachments and connections. These are better understood with reference to the embryological development of this region. Armed with this knowledge, the diagnosis and assessment of a wide range of common intra-abdominal diseases becomes straightforward. This article will review and simplify the terminology, complex embryological development, and anatomy of the peritoneum, peritoneal attachments, and the reflections forming the peritoneal boundaries. Normal anatomy will be described using schematic diagrams with corresponding computed tomography (CT) and magnetic resonance imaging (MRI) images, including CT peritoneograms. The relevance of intra- and extra-peritoneal anatomy to common pathological processes will be demonstrated

  14. Introduction to applied thermodynamics

    CERN Document Server

    Helsdon, R M; Walker, G E

    1965-01-01

    Introduction to Applied Thermodynamics is an introductory text on applied thermodynamics and covers topics ranging from energy and temperature to reversibility and entropy, the first and second laws of thermodynamics, and the properties of ideal gases. Standard air cycles and the thermodynamic properties of pure substances are also discussed, together with gas compressors, combustion, and psychrometry. This volume is comprised of 16 chapters and begins with an overview of the concept of energy as well as the macroscopic and molecular approaches to thermodynamics. The following chapters focus o

  15. Applying the accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Barbalat, Oscar

    1989-12-15

    Originally developed as tools for frontier physics, particle accelerators provide valuable spinoff benefits in applied research and technology. These accelerator applications are the subject of a biennial meeting in Denton, Texas, but the increasing activity in this field resulted this year (5-9 September) in the first European Conference on Accelerators in Applied Research and Technology, organized by K. Bethge of Frankfurt's Goethe University. The meeting reflected a wide range of applications - ion beam analysis, exploitation of nuclear microbeams, accelerator mass spectrometry, applications of photonuclear reactions, ion beam processing, synchrotron radiation for semiconductor technology, specialized technology.

  16. Applied mathematics made simple

    CERN Document Server

    Murphy, Patrick

    1982-01-01

    Applied Mathematics: Made Simple provides an elementary study of the three main branches of classical applied mathematics: statics, hydrostatics, and dynamics. The book begins with discussion of the concepts of mechanics, parallel forces and rigid bodies, kinematics, motion with uniform acceleration in a straight line, and Newton's law of motion. Separate chapters cover vector algebra and coplanar motion, relative motion, projectiles, friction, and rigid bodies in equilibrium under the action of coplanar forces. The final chapters deal with machines and hydrostatics. The standard and conte

  17. Applying the accelerator

    International Nuclear Information System (INIS)

    Barbalat, Oscar

    1989-01-01

    Originally developed as tools for frontier physics, particle accelerators provide valuable spinoff benefits in applied research and technology. These accelerator applications are the subject of a biennial meeting in Denton, Texas, but the increasing activity in this field resulted this year (5-9 September) in the first European Conference on Accelerators in Applied Research and Technology, organized by K. Bethge of Frankfurt's Goethe University. The meeting reflected a wide range of applications - ion beam analysis, exploitation of nuclear microbeams, accelerator mass spectrometry, applications of photonuclear reactions, ion beam processing, synchrotron radiation for semiconductor technology, specialized technology

  18. On applying cognitive psychology.

    Science.gov (United States)

    Baddeley, Alan

    2013-11-01

    Recent attempts to assess the practical impact of scientific research prompted my own reflections on over 40 years worth of combining basic and applied cognitive psychology. Examples are drawn principally from the study of memory disorders, but also include applications to the assessment of attention, reading, and intelligence. The most striking conclusion concerns the many years it typically takes to go from an initial study, to the final practical outcome. Although the complexity and sheer timescale involved make external evaluation problematic, the combination of practical satisfaction and theoretical stimulation make the attempt to combine basic and applied research very rewarding. © 2013 The British Psychological Society.

  19. Applied Computational Intelligence for finance and economics

    OpenAIRE

    Isasi Viñuela, Pedro; Quintana Montero, David; Sáez Achaerandio, Yago; Mochón, Asunción

    2007-01-01

    This article introduces some relevant research works on computational intelligence applied to finance and economics. The objective is to offer an appropriate context and a starting point for those who are new to computational intelligence in finance and economics and to give an overview of the most recent works. A classification with five different main areas is presented. Those areas are related with different applications of the most modern computational intelligence techniques showing a ne...

  20. Applying incentive sensitization models to behavioral addiction

    DEFF Research Database (Denmark)

    Rømer Thomsen, Kristine; Fjorback, Lone; Møller, Arne

    2014-01-01

    The incentive sensitization theory is a promising model for understanding the mechanisms underlying drug addiction, and has received support in animal and human studies. So far the theory has not been applied to the case of behavioral addictions like Gambling Disorder, despite sharing clinical...... symptoms and underlying neurobiology. We examine the relevance of this theory for Gambling Disorder and point to predictions for future studies. The theory promises a significant contribution to the understanding of behavioral addiction and opens new avenues for treatment....

  1. Does relevance matter in academic policy research

    DEFF Research Database (Denmark)

    Dredge, Dianne

    2015-01-01

    A reflection on whether relevance matters in tourism policy research, and if so, to whom/what should it matter......A reflection on whether relevance matters in tourism policy research, and if so, to whom/what should it matter...

  2. Inoculating Relevance Feedback Against Poison Pills

    NARCIS (Netherlands)

    Dehghani, Mostafa; Azarbonyad, Hosein; Kamps, Jaap; Hiemstra, Djoerd; Marx, Maarten

    2016-01-01

    Relevance Feedback is a common approach for enriching queries, given a set of explicitly or implicitly judged documents to improve the performance of the retrieval. Although it has been shown that on average, the overall performance of retrieval will be improved after relevance feedback, for some

  3. Relevant cost information for order acceptance decisions

    NARCIS (Netherlands)

    Wouters, M.J.F.

    1997-01-01

    Some economic considerations for order acceptance decisions are discussed. The relevant economic considerations for order acceptance are widely discussed in the literature: only those costs are relevant which would be avoidable by not accepting the order incremental costs plus opportunity costs .

  4. Android Smartphone Relevance to Military Weather Applications

    Science.gov (United States)

    2011-10-01

    lithium -ion battery that may be replaced by the user (unlike Apple iPod Touch devices), thus spare batteries can be carried. If there is only sporadic...Android Smartphone Relevance to Military Weather Applications by David Sauter ARL-TR-5793 October 2011...Android Smartphone Relevance to Military Weather Applications David Sauter Computational and Information Sciences Directorate, ARL

  5. Using small XML elements to support relevance

    NARCIS (Netherlands)

    G. Ramirez Camps (Georgina); T.H.W. Westerveld (Thijs); A.P. de Vries (Arjen)

    2006-01-01

    htmlabstractSmall XML elements are often estimated relevant by the retrieval model but they are not desirable retrieval units. This paper presents a generic model that exploits the information obtained from small elements. We identify relationships between small and relevant elements and use this

  6. Translation as secondary communication. The relevance theory ...

    African Journals Online (AJOL)

    Ernst-August Gutt started one of the greatest translation debates of the past ten years when he suggested that relevance theory holds the key to providing a unified account of translation. The bulk of the debate has been between practitioners of functional equivalence and advocates of a relevance theoretic approach to ...

  7. Advances in applied mechanics

    CERN Document Server

    Wu, Theodore Y; Wu, Theodore Y

    2000-01-01

    This highly acclaimed series provides survey articles on the present state and future direction of research in important branches of applied solid and fluid mechanics. Mechanics is defined as a branch of physics that focuses on motion and on the reaction of physical systems to internal and external forces.

  8. Essays on Applied Microeconomics

    Science.gov (United States)

    Mejia Mantilla, Carolina

    2013-01-01

    Each chapter of this dissertation studies a different question within the field of Applied Microeconomics. The first chapter examines the mid- and long-term effects of the 1998 Asian Crisis on the educational attainment of Indonesian children ages 6 to 18, at the time of the crisis. The effects are identified as deviations from a linear trend for…

  9. Signals: Applying Academic Analytics

    Science.gov (United States)

    Arnold, Kimberly E.

    2010-01-01

    Academic analytics helps address the public's desire for institutional accountability with regard to student success, given the widespread concern over the cost of higher education and the difficult economic and budgetary conditions prevailing worldwide. Purdue University's Signals project applies the principles of analytics widely used in…

  10. Journal of Applied Biosciences

    African Journals Online (AJOL)

    The Journal of Applied Biosciences provides a forum for scholars and practitioners in all spheres of biological sciences to publish their research findings or theoretical concepts and ideas of a scientific nature. Other websites related to this journal: http://m.elewa.org/Journals/about-jab/ ...

  11. Thermodynamics applied. Where? Why?

    NARCIS (Netherlands)

    Hirs, Gerard

    2003-01-01

    In recent years, thermodynamics has been applied in a number of new fields leading to a greater societal impact. This paper gives a survey of these new fields and the reasons why these applications are important. In addition, it is shown that the number of fields could be even greater in the future

  12. Thermodynamics, applied. : Where? why?

    NARCIS (Netherlands)

    Hirs, Gerard

    1999-01-01

    In recent years thermodynamics has been applied in a number of new fields leading to a greater societal impact. The paper gives a survey of these new fields and the reasons why these applications are important. In addition it is shown that the number of fields could be even greater in the future and

  13. Applied Statistics with SPSS

    Science.gov (United States)

    Huizingh, Eelko K. R. E.

    2007-01-01

    Accessibly written and easy to use, "Applied Statistics Using SPSS" is an all-in-one self-study guide to SPSS and do-it-yourself guide to statistics. What is unique about Eelko Huizingh's approach is that this book is based around the needs of undergraduate students embarking on their own research project, and its self-help style is designed to…

  14. Applied research on glucansucrases

    Science.gov (United States)

    Although glycansucrases have been known for over 70 years, they remain relatively unknown except to a small group of researchers. Practical, applied research on glycansucrases has been focused on certain key areas. The earliest of these was the development of blood plasma extenders from dextran, d...

  15. Essays in applied microeconometrics

    NARCIS (Netherlands)

    Cervený, Jakub

    2017-01-01

    Duration analysis has been widely used in the applied economic research since the late 1970s. The framework allows to examine the duration of time intervals and the rate of transition across a set of states over time. Many economic behaviors follow a similar pattern, such as transition from the

  16. Applied Behavior Analysis

    Science.gov (United States)

    Szapacs, Cindy

    2006-01-01

    Teaching strategies that work for typically developing children often do not work for those diagnosed with an autism spectrum disorder. However, teaching strategies that work for children with autism do work for typically developing children. In this article, the author explains how the principles and concepts of Applied Behavior Analysis can be…

  17. Applied Linguistics in Europe

    NARCIS (Netherlands)

    de Bot, Kees

    2004-01-01

    In this contribution developments in Applied Linguistics in Europe are linked to major social changes that have taken place over the last decades. These include: The decline of the USSR and the end of the cold war; The development of the EEC and the EU and fading of borders; The economic growth of

  18. Applied Anthropology in Broadcasting

    Science.gov (United States)

    Eiselein, E. B.

    1976-01-01

    Three different applied media anthropology projects are described. These projects stem from the broadcasters' legal need to know about the community (community ascertainment), the broadcasters' need to know about the station audience (audience profile), and the broadcasters' desire to change a community (action projects). (Author)

  19. Evolutionary relevance facilitates visual information processing.

    Science.gov (United States)

    Jackson, Russell E; Calvillo, Dusti P

    2013-11-03

    Visual search of the environment is a fundamental human behavior that perceptual load affects powerfully. Previously investigated means for overcoming the inhibitions of high perceptual load, however, generalize poorly to real-world human behavior. We hypothesized that humans would process evolutionarily relevant stimuli more efficiently than evolutionarily novel stimuli, and evolutionary relevance would mitigate the repercussions of high perceptual load during visual search. Animacy is a significant component to evolutionary relevance of visual stimuli because perceiving animate entities is time-sensitive in ways that pose significant evolutionary consequences. Participants completing a visual search task located evolutionarily relevant and animate objects fastest and with the least impact of high perceptual load. Evolutionarily novel and inanimate objects were located slowest and with the highest impact of perceptual load. Evolutionary relevance may importantly affect everyday visual information processing.

  20. Evolutionary Relevance Facilitates Visual Information Processing

    Directory of Open Access Journals (Sweden)

    Russell E. Jackson

    2013-07-01

    Full Text Available Visual search of the environment is a fundamental human behavior that perceptual load affects powerfully. Previously investigated means for overcoming the inhibitions of high perceptual load, however, generalize poorly to real-world human behavior. We hypothesized that humans would process evolutionarily relevant stimuli more efficiently than evolutionarily novel stimuli, and evolutionary relevance would mitigate the repercussions of high perceptual load during visual search. Animacy is a significant component to evolutionary relevance of visual stimuli because perceiving animate entities is time-sensitive in ways that pose significant evolutionary consequences. Participants completing a visual search task located evolutionarily relevant and animate objects fastest and with the least impact of high perceptual load. Evolutionarily novel and inanimate objects were located slowest and with the highest impact of perceptual load. Evolutionary relevance may importantly affect everyday visual information processing.

  1. Applied Control Systems Design

    CERN Document Server

    Mahmoud, Magdi S

    2012-01-01

    Applied Control System Design examines several methods for building up systems models based on real experimental data from typical industrial processes and incorporating system identification techniques. The text takes a comparative approach to the models derived in this way judging their suitability for use in different systems and under different operational circumstances. A broad spectrum of control methods including various forms of filtering, feedback and feedforward control is applied to the models and the guidelines derived from the closed-loop responses are then composed into a concrete self-tested recipe to serve as a check-list for industrial engineers or control designers. System identification and control design are given equal weight in model derivation and testing to reflect their equality of importance in the proper design and optimization of high-performance control systems. Readers’ assimilation of the material discussed is assisted by the provision of problems and examples. Most of these e...

  2. APPLIED ORGANIZATION OF CONSTRUCTION

    Directory of Open Access Journals (Sweden)

    Kievskiy Leonid Vladimirovich

    2017-03-01

    Full Text Available Applied disciplines in the sphere of construction which are engaged in the solution of vital macroeconomical problems (the general trend of development of these disciplines is the expansion of problematics and mutual integration are considered. Construction organization characteristic at the present stage as a systems engineering discipline covering the investment process of creation of real estate items, is given. The main source of current research trends for applied sciences (socio-economic development forecasts, regional and local programs is determined. Interpenetration and integration of various fields of knowledge exemplified by the current interindustry problem of blocks renovation organization of existing development, is demonstrated. Mathematical model of wave construction (for the period of deployment is proposed. Nature of dependence of the total duration of renovation on the limit of annual input and coefficient of renovation, is established. Overall structure of the Moscow region housing market is presented, and approaches to definition of effective demand are proposed.

  3. Applied evaluative informetrics

    CERN Document Server

    Moed, Henk F

    2017-01-01

    This book focuses on applied evaluative informetric artifacts or topics. It explains the base notions and assumptions of evaluative informetrics by discussing a series of important applications. The structure of the book is therefore not organized by methodological characteristics, but is centered around popular, often discussed or used informetric artifacts - indicators, methodologies, products, databases - or so called hot topics in which informetric indicators play an important role. Most of the artifacts and topics emerged during the past decade. The principal aim of the book is to present a state of the art in applied evaluative informetrics, and to inform the readers about the pros and cons, potentialities and limitations of the use of informetric/bibliometric indicators in research assessment. The book is a continuation of the book Citation Analysis in Research Evaluation (Springer, 2005). It is of interest to non-specialists, especially research students at advanced master level and higher, all thos...

  4. Applied statistics for economists

    CERN Document Server

    Lewis, Margaret

    2012-01-01

    This book is an undergraduate text that introduces students to commonly-used statistical methods in economics. Using examples based on contemporary economic issues and readily-available data, it not only explains the mechanics of the various methods, it also guides students to connect statistical results to detailed economic interpretations. Because the goal is for students to be able to apply the statistical methods presented, online sources for economic data and directions for performing each task in Excel are also included.

  5. Methods of applied mathematics

    CERN Document Server

    Hildebrand, Francis B

    1992-01-01

    This invaluable book offers engineers and physicists working knowledge of a number of mathematical facts and techniques not commonly treated in courses in advanced calculus, but nevertheless extremely useful when applied to typical problems in many different fields. It deals principally with linear algebraic equations, quadratic and Hermitian forms, operations with vectors and matrices, the calculus of variations, and the formulations and theory of linear integral equations. Annotated problems and exercises accompany each chapter.

  6. Applied longitudinal analysis

    CERN Document Server

    Fitzmaurice, Garrett M; Ware, James H

    2012-01-01

    Praise for the First Edition "". . . [this book] should be on the shelf of everyone interested in . . . longitudinal data analysis.""-Journal of the American Statistical Association   Features newly developed topics and applications of the analysis of longitudinal data Applied Longitudinal Analysis, Second Edition presents modern methods for analyzing data from longitudinal studies and now features the latest state-of-the-art techniques. The book emphasizes practical, rather than theoretical, aspects of methods for the analysis of diverse types of lo

  7. Applied clinical engineering

    International Nuclear Information System (INIS)

    Feinberg, B.

    1986-01-01

    This book demonstrates how clinical engineering has applied engineering principles to the development and use of complex medical devices for the diagnosis and treatment of the sick and injured. It discusses the proper utilization of medical devices and equipment in the health-care industry and provides understanding of complex engineering systems, and their uses in the modern hospital or other health-care facility

  8. Astrophysical relevance of γ transition energies

    International Nuclear Information System (INIS)

    Rauscher, Thomas

    2008-01-01

    The relevant γ energy range is explicitly identified where additional γ strength must be located to have an impact on astrophysically relevant reactions. It is shown that folding the energy dependences of the transmission coefficients and the level density leads to maximal contributions for γ energies of 2≤E γ ≤4 unless quantum selection rules allow isolated states to contribute. Under this condition, electric dipole transitions dominate. These findings allow us to more accurately judge the relevance of modifications of the γ strength for astrophysics

  9. Neutrophil programming dynamics and its disease relevance.

    Science.gov (United States)

    Ran, Taojing; Geng, Shuo; Li, Liwu

    2017-11-01

    Neutrophils are traditionally considered as first responders to infection and provide antimicrobial host defense. However, recent advances indicate that neutrophils are also critically involved in the modulation of host immune environments by dynamically adopting distinct functional states. Functionally diverse neutrophil subsets are increasingly recognized as critical components mediating host pathophysiology. Despite its emerging significance, molecular mechanisms as well as functional relevance of dynamically programmed neutrophils remain to be better defined. The increasing complexity of neutrophil functions may require integrative studies that address programming dynamics of neutrophils and their pathophysiological relevance. This review aims to provide an update on the emerging topics of neutrophil programming dynamics as well as their functional relevance in diseases.

  10. Determination of the relevant market as a criterion of assessment of concentration effects in the practice of antitrust authorities

    Directory of Open Access Journals (Sweden)

    Daria Kostecka-Jurczyk

    2012-12-01

    Full Text Available Determining the relevant market is the first and the most important step in antimonopoly proceedings due to the fact that the market position of an enterprise is always determined from the relevant market perspective. In respect of mergers, establishing the relevant market is essential in analysing whether the aim of the concentration is to distort and limit competition on the market. The author of the article focuses on describing methods for determining the relevant market applied by antimonopoly authorities.

  11. Summarizing Simulation Results using Causally-relevant States

    Science.gov (United States)

    Parikh, Nidhi; Marathe, Madhav; Swarup, Samarth

    2016-01-01

    As increasingly large-scale multiagent simulations are being implemented, new methods are becoming necessary to make sense of the results of these simulations. Even concisely summarizing the results of a given simulation run is a challenge. Here we pose this as the problem of simulation summarization: how to extract the causally-relevant descriptions of the trajectories of the agents in the simulation. We present a simple algorithm to compress agent trajectories through state space by identifying the state transitions which are relevant to determining the distribution of outcomes at the end of the simulation. We present a toy-example to illustrate the working of the algorithm, and then apply it to a complex simulation of a major disaster in an urban area. PMID:28042620

  12. Strategic approach to branding of nations: Relevancy for Serbia

    Directory of Open Access Journals (Sweden)

    Rakita Branko

    2009-01-01

    Full Text Available Building and managing brands becomes very important marketing tool in nowadays business. Branding is being pulled out from a strictly marketing area and becomes business component of a strategic importance. It is applying to products, services, companies, but also to events, people, ideas, institutions, destinations. Basically, almost everything can be branded. The subject of this paper is strategic approach to branding of nations. The paper contains review of relevant literature for the topic. Specifics of this type of branding have been analyzed. Detailed concept of strategic approach to branding of nations is a vital part of the paper. Relevancy of strategic approach to branding for Serbia is discussed at the end.

  13. The foundation of the concept of relevance

    DEFF Research Database (Denmark)

    Hjørland, Birger

    2010-01-01

    that what was regarded as the most fundamental view by Saracevic in 1975 has not since been considered (with very few exceptions). Other views, which are based on less fruitful assumptions, have dominated the discourse on relevance in information retrieval and information science. Many authors have...... reexamined the concept of relevance in information science, but have neglected the subject knowledge view, hence basic theoretical assumptions seem not to have been properly addressed. It is as urgent now as it was in 1975 seriously to consider “the subject knowledge view” of relevance (which may also...... be termed “the epistemological view”). The concept of relevance, like other basic concepts, is influenced by overall approaches to information science, such as the cognitive view and the domain-analytic view. There is today a trend toward a social paradigm for information science. This paper offers...

  14. Applied ALARA techniques

    International Nuclear Information System (INIS)

    Waggoner, L.O.

    1998-01-01

    The presentation focuses on some of the time-proven and new technologies being used to accomplish radiological work. These techniques can be applied at nuclear facilities to reduce radiation doses and protect the environment. The last reactor plants and processing facilities were shutdown and Hanford was given a new mission to put the facilities in a safe condition, decontaminate, and prepare them for decommissioning. The skills that were necessary to operate these facilities were different than the skills needed today to clean up Hanford. Workers were not familiar with many of the tools, equipment, and materials needed to accomplish:the new mission, which includes clean up of contaminated areas in and around all the facilities, recovery of reactor fuel from spent fuel pools, and the removal of millions of gallons of highly radioactive waste from 177 underground tanks. In addition, this work has to be done with a reduced number of workers and a smaller budget. At Hanford, facilities contain a myriad of radioactive isotopes that are 2048 located inside plant systems, underground tanks, and the soil. As cleanup work at Hanford began, it became obvious early that in order to get workers to apply ALARA and use hew tools and equipment to accomplish the radiological work it was necessary to plan the work in advance and get radiological control and/or ALARA committee personnel involved early in the planning process. Emphasis was placed on applying,ALARA techniques to reduce dose, limit contamination spread and minimize the amount of radioactive waste generated. Progress on the cleanup has,b6en steady and Hanford workers have learned to use different types of engineered controls and ALARA techniques to perform radiological work. The purpose of this presentation is to share the lessons learned on how Hanford is accomplishing radiological work

  15. Applied ALARA techniques

    Energy Technology Data Exchange (ETDEWEB)

    Waggoner, L.O.

    1998-02-05

    The presentation focuses on some of the time-proven and new technologies being used to accomplish radiological work. These techniques can be applied at nuclear facilities to reduce radiation doses and protect the environment. The last reactor plants and processing facilities were shutdown and Hanford was given a new mission to put the facilities in a safe condition, decontaminate, and prepare them for decommissioning. The skills that were necessary to operate these facilities were different than the skills needed today to clean up Hanford. Workers were not familiar with many of the tools, equipment, and materials needed to accomplish:the new mission, which includes clean up of contaminated areas in and around all the facilities, recovery of reactor fuel from spent fuel pools, and the removal of millions of gallons of highly radioactive waste from 177 underground tanks. In addition, this work has to be done with a reduced number of workers and a smaller budget. At Hanford, facilities contain a myriad of radioactive isotopes that are 2048 located inside plant systems, underground tanks, and the soil. As cleanup work at Hanford began, it became obvious early that in order to get workers to apply ALARA and use hew tools and equipment to accomplish the radiological work it was necessary to plan the work in advance and get radiological control and/or ALARA committee personnel involved early in the planning process. Emphasis was placed on applying,ALARA techniques to reduce dose, limit contamination spread and minimize the amount of radioactive waste generated. Progress on the cleanup has,b6en steady and Hanford workers have learned to use different types of engineered controls and ALARA techniques to perform radiological work. The purpose of this presentation is to share the lessons learned on how Hanford is accomplishing radiological work.

  16. Applied Semantic Web Technologies

    CERN Document Server

    Sugumaran, Vijayan

    2011-01-01

    The rapid advancement of semantic web technologies, along with the fact that they are at various levels of maturity, has left many practitioners confused about the current state of these technologies. Focusing on the most mature technologies, Applied Semantic Web Technologies integrates theory with case studies to illustrate the history, current state, and future direction of the semantic web. It maintains an emphasis on real-world applications and examines the technical and practical issues related to the use of semantic technologies in intelligent information management. The book starts with

  17. SIFT applied to CBIR

    Directory of Open Access Journals (Sweden)

    ALMEIDA, J.

    2009-12-01

    Full Text Available Content-Based Image Retrieval (CBIR is a challenging task. Common approaches use only low-level features. Notwithstanding, such CBIR solutions fail on capturing some local features representing the details and nuances of scenes. Many techniques in image processing and computer vision can capture these scene semantics. Among them, the Scale Invariant Features Transform~(SIFT has been widely used in a lot of applications. This approach relies on the choice of several parameters which directly impact its effectiveness when applied to retrieve images. In this paper, we discuss the results obtained in several experiments proposed to evaluate the application of the SIFT in CBIR tasks.

  18. Applied impulsive mathematical models

    CERN Document Server

    Stamova, Ivanka

    2016-01-01

    Using the theory of impulsive differential equations, this book focuses on mathematical models which reflect current research in biology, population dynamics, neural networks and economics. The authors provide the basic background from the fundamental theory and give a systematic exposition of recent results related to the qualitative analysis of impulsive mathematical models. Consisting of six chapters, the book presents many applicable techniques, making them available in a single source easily accessible to researchers interested in mathematical models and their applications. Serving as a valuable reference, this text is addressed to a wide audience of professionals, including mathematicians, applied researchers and practitioners.

  19. Applied energy an introduction

    CERN Document Server

    Abdullah, Mohammad Omar

    2012-01-01

    Introduction to Applied EnergyGeneral IntroductionEnergy and Power BasicsEnergy EquationEnergy Generation SystemsEnergy Storage and MethodsEnergy Efficiencies and LossesEnergy industry and Energy Applications in Small -Medium Enterprises (SME) industriesEnergy IndustryEnergy-Intensive industryEnergy Applications in SME Energy industriesEnergy Sources and SupplyEnergy SourcesEnergy Supply and Energy DemandEnergy Flow Visualization and Sankey DiagramEnergy Management and AnalysisEnergy AuditsEnergy Use and Fuel Consumption StudyEnergy Life-Cycle AnalysisEnergy and EnvironmentEnergy Pollutants, S

  20. Applied linear regression

    CERN Document Server

    Weisberg, Sanford

    2013-01-01

    Praise for the Third Edition ""...this is an excellent book which could easily be used as a course text...""-International Statistical Institute The Fourth Edition of Applied Linear Regression provides a thorough update of the basic theory and methodology of linear regression modeling. Demonstrating the practical applications of linear regression analysis techniques, the Fourth Edition uses interesting, real-world exercises and examples. Stressing central concepts such as model building, understanding parameters, assessing fit and reliability, and drawing conclusions, the new edition illus

  1. Applied Meteorology Unit (AMU)

    Science.gov (United States)

    Bauman, William; Crawford, Winifred; Barrett, Joe; Watson, Leela; Wheeler, Mark

    2010-01-01

    This report summarizes the Applied Meteorology Unit (AMU) activities for the first quarter of Fiscal Year 2010 (October - December 2009). A detailed project schedule is included in the Appendix. Included tasks are: (1) Peak Wind Tool for User Launch Commit Criteria (LCC), (2) Objective Lightning Probability Tool, Phase III, (3) Peak Wind Tool for General Forecasting, Phase II, (4) Upgrade Summer Severe Weather Tool in Meteorological Interactive Data Display System (MIDDS), (5) Advanced Regional Prediction System (ARPS) Data Analysis System (ADAS) Update and Maintainability, (5) Verify 12-km resolution North American Model (MesoNAM) Performance, and (5) Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) Graphical User Interface.

  2. Applied logistic regression

    CERN Document Server

    Hosmer, David W; Sturdivant, Rodney X

    2013-01-01

     A new edition of the definitive guide to logistic regression modeling for health science and other applications This thoroughly expanded Third Edition provides an easily accessible introduction to the logistic regression (LR) model and highlights the power of this model by examining the relationship between a dichotomous outcome and a set of covariables. Applied Logistic Regression, Third Edition emphasizes applications in the health sciences and handpicks topics that best suit the use of modern statistical software. The book provides readers with state-of-

  3. Analytic framework for peptidomics applied to large-scale neuropeptide identification

    DEFF Research Database (Denmark)

    Secher, Anna; Kelstrup, Christian D; Conde-Frieboes, Kilian W

    2016-01-01

    was integrated with publically available databases. We developed and applied an algorithm that reduces the peptide complexity for identification of biologically relevant peptides. The developed pipeline was applied to rat hypothalamus and identifies thousands of neuropeptides and their post...

  4. Natural brain-information interfaces: Recommending information by relevance inferred from human brain signals

    Science.gov (United States)

    Eugster, Manuel J. A.; Ruotsalo, Tuukka; Spapé, Michiel M.; Barral, Oswald; Ravaja, Niklas; Jacucci, Giulio; Kaski, Samuel

    2016-01-01

    Finding relevant information from large document collections such as the World Wide Web is a common task in our daily lives. Estimation of a user’s interest or search intention is necessary to recommend and retrieve relevant information from these collections. We introduce a brain-information interface used for recommending information by relevance inferred directly from brain signals. In experiments, participants were asked to read Wikipedia documents about a selection of topics while their EEG was recorded. Based on the prediction of word relevance, the individual’s search intent was modeled and successfully used for retrieving new relevant documents from the whole English Wikipedia corpus. The results show that the users’ interests toward digital content can be modeled from the brain signals evoked by reading. The introduced brain-relevance paradigm enables the recommendation of information without any explicit user interaction and may be applied across diverse information-intensive applications. PMID:27929077

  5. Introduction to Search with Sphinx From installation to relevance tuning

    CERN Document Server

    Aksyonoff, Andrew

    2011-01-01

    This concise introduction to Sphinx shows you how to use this free software to index an enormous number of documents and provide fast results to both simple and complex searches. Written by the creator of Sphinx, this authoritative book is short and to the point. Understand the particular way Sphinx conducts searchesInstall and configure Sphinx, and run a few basic testsIssue basic queries to Sphinx at the application levelLearn the syntax of search text and the effects of various search optionsGet strategies for dealing with large data sets, such as multi-index searchingApply relevance and r

  6. Identifying relevant feature-action associations for grasping unmodelled objects

    DEFF Research Database (Denmark)

    Thomsen, Mikkel Tang; Kraft, Dirk; Krüger, Norbert

    2015-01-01

    content. The method is provided with a large and structured set of visual features, motivated by the visual hierarchy in primates and finds relevant feature action associations automatically. We apply our method in a simulated environment on three different object sets for the case of grasp affordance...... learning. For box objects, we achieve a 0.90 success probability, 0.80 for round objects and up to 0.75 for open objects, when presented with novel objects. In this work, we in particular demonstrate the effect of choosing appropriate feature representations. We demonstrate a significant performance...

  7. THE RELEVANT TEMPORAL MARKET DEFINITION IN ANTITRUST ANALYSIS

    Directory of Open Access Journals (Sweden)

    Anzhelika Gerasymenko

    2018-01-01

    Full Text Available The purpose of the paper is to compare various theoretical approaches to the relevant temporal market definition, collecting the arguments for their implementation under the different kinds of antitrust cases. It is vital for the markets with peak demand (transport, electricity, markets of intergenerational products or discreet supply (agriculture. Methodology. The survey is based on the theoretical and graphical modelling of product space perception by consumers. It investigates changes of the latter under different marketing strategies of a seller. Statistical methods are used to analyse trends of demand and prices for iPhones’ changes, as well as dynamics of electricity consumption. Results. The paper reveals two facing approaches to the definition of relevant temporal market: 1 the discrete one that provides a short-run analysis of products’ substitutability and combines only those time periods that are characterized by a stable balance of demand and supply, as well as stable market equilibrium; 2 the coherent one that provides a long-run analysis of cyclical variation of the market. This cycling is based on the awareness of consumers and producers of intertemporal substitutability of products. The authors use the model of intertemporal competition to explain principles of these approaches and apply it to the iPhone market analysis. They conclude that the coherent approach must be applied to the temporal market definition for the products with elastic demand. Inelastic demand brings the necessity to apply the discrete approach to the temporal market definition. These conclusions cannot be applied to regulated markets. The system of government regulation is the main determinant of the temporal boundaries of such markets. Practical implications. The results of this research can be used by competition agencies in antitrust cases to define the relevant temporal market, where the violations of antitrust legislation can occur. The correct

  8. [The G-DRG System 2009--relevant changes for rheumatology].

    Science.gov (United States)

    Fiori, W; Liedtke-Dyong, A; Lakomek, H-J; Buscham, K; Lehmann, H; Liman, W; Fuchs, A-K; Bessler, F; Roeder, N

    2010-05-01

    The following article presents the major general and specific changes in the G-DRG system, in the classification systems for diagnoses and procedures as well as for the billing process for 2010. Since the G-DRG system is primarily a tool for the redistribution of resources, every hospital needs to analyze the economic effects of the changes by applying the G-DRG transition-grouper to its own cases. Depending on their clinical focus, rheumatological departments may experience positive or negative consequences from the adjustments. In addition, relevant current case law is considered.

  9. Applied plasma physics

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    Applied Plasma Physics is a major sub-organizational unit of the Magnetic Fusion Energy (MFE) Program. It includes Fusion Plasma Theory and Experimental Plasma Research. The Fusion Plasma Theory group has the responsibility for developing theoretical-computational models in the general areas of plasma properties, equilibrium, stability, transport, and atomic physics. This group has responsibility for giving guidance to the mirror experimental program. There is a formal division of the group into theory and computational; however, in this report the efforts of the two areas are not separated since many projects have contributions from members of both. Under the Experimental Plasma Research Program we are developing a neutral-beam source, the intense, pulsed ion-neutral source (IPINS), for the generation of a reversed-field configuration on 2XIIB. We are also studying the feasibility of using certain neutron-detection techniques as plasma diagnostics in the next generation of thermonuclear experiments

  10. Applied antineutrino physics workshop

    International Nuclear Information System (INIS)

    Lund, James C.

    2008-01-01

    This workshop is the fourth one of a series that includes the Neutrino Geophysics Conference at Honolulu, Hawaii, which I attended in 2005. This workshop was organized by the Astro-Particle and Cosmology laboratory in the recently opened Condoret building of the University of Paris. More information, including copies of the presentations, on the workshop is available on the website: www.apc.univ-paris7.fr/AAP2007/. The workshop aims at opening neutrino physics to various fields such that it can be applied in geosciences, nuclear industry (reactor and spent fuel monitoring) and non-proliferation. The workshop was attended by over 60 people from Europe, USA, Asia and Brazil. The meeting was also attended by representatives of the Comprehensive nuclear-Test Ban Treaty (CTBT) and the International Atomic Energy Agency (IAEA). The workshop also included a workshop dinner on board of a river boat sailing the Seine river

  11. Applied partial differential equations

    CERN Document Server

    Logan, J David

    2015-01-01

    This text presents the standard material usually covered in a one-semester, undergraduate course on boundary value problems and PDEs.  Emphasis is placed on motivation, concepts, methods, and interpretation, rather than on formal theory. The concise treatment of the subject is maintained in this third edition covering all the major ideas: the wave equation, the diffusion equation, the Laplace equation, and the advection equation on bounded and unbounded domains. Methods include eigenfunction expansions, integral transforms, and characteristics. In this third edition, text remains intimately tied to applications in heat transfer, wave motion, biological systems, and a variety other topics in pure and applied science. The text offers flexibility to instructors who, for example, may wish to insert topics from biology or numerical methods at any time in the course. The exposition is presented in a friendly, easy-to-read, style, with mathematical ideas motivated from physical problems. Many exercises and worked e...

  12. Applied computational physics

    CERN Document Server

    Boudreau, Joseph F; Bianchi, Riccardo Maria

    2018-01-01

    Applied Computational Physics is a graduate-level text stressing three essential elements: advanced programming techniques, numerical analysis, and physics. The goal of the text is to provide students with essential computational skills that they will need in their careers, and to increase the confidence with which they write computer programs designed for their problem domain. The physics problems give them an opportunity to reinforce their programming skills, while the acquired programming skills augment their ability to solve physics problems. The C++ language is used throughout the text. Physics problems include Hamiltonian systems, chaotic systems, percolation, critical phenomena, few-body and multi-body quantum systems, quantum field theory, simulation of radiation transport, and data modeling. The book, the fruit of a collaboration between a theoretical physicist and an experimental physicist, covers a broad range of topics from both viewpoints. Examples, program libraries, and additional documentatio...

  13. Applied statistical thermodynamics

    CERN Document Server

    Lucas, Klaus

    1991-01-01

    The book guides the reader from the foundations of statisti- cal thermodynamics including the theory of intermolecular forces to modern computer-aided applications in chemical en- gineering and physical chemistry. The approach is new. The foundations of quantum and statistical mechanics are presen- ted in a simple way and their applications to the prediction of fluid phase behavior of real systems are demonstrated. A particular effort is made to introduce the reader to expli- cit formulations of intermolecular interaction models and to show how these models influence the properties of fluid sy- stems. The established methods of statistical mechanics - computer simulation, perturbation theory, and numerical in- tegration - are discussed in a style appropriate for newcom- ers and are extensively applied. Numerous worked examples illustrate how practical calculations should be carried out.

  14. Applied plasma physics

    International Nuclear Information System (INIS)

    Anon.

    1978-01-01

    Applied Plasma Physics is a major sub-organizational unit of the MFE Program. It includes Fusion Plasma Theory and Experimental Plasma Research. The Fusion Plasma Theory group has the responsibility for developing theoretical-computational models in the general areas of plasma properties, equilibrium, stability, transport, and atomic physics. This group has responsibility for giving guidance to the mirror experimental program. There is a formal division of the group into theory and computational; however, in this report the efforts of the two areas are not separated since many projects have contributions from members of both. Under the Experimental Plasma Research Program, we are developing the intense, pulsed neutral-beam source (IPINS) for the generation of a reversed-field configuration on 2XIIB. We are also studying the feasibility of utilizing certain neutron-detection techniques as plasma diagnostics in the next generation of thermonuclear experiments

  15. Applied linear algebra

    CERN Document Server

    Olver, Peter J

    2018-01-01

    This textbook develops the essential tools of linear algebra, with the goal of imparting technique alongside contextual understanding. Applications go hand-in-hand with theory, each reinforcing and explaining the other. This approach encourages students to develop not only the technical proficiency needed to go on to further study, but an appreciation for when, why, and how the tools of linear algebra can be used across modern applied mathematics. Providing an extensive treatment of essential topics such as Gaussian elimination, inner products and norms, and eigenvalues and singular values, this text can be used for an in-depth first course, or an application-driven second course in linear algebra. In this second edition, applications have been updated and expanded to include numerical methods, dynamical systems, data analysis, and signal processing, while the pedagogical flow of the core material has been improved. Throughout, the text emphasizes the conceptual connections between each application and the un...

  16. Applied number theory

    CERN Document Server

    Niederreiter, Harald

    2015-01-01

    This textbook effectively builds a bridge from basic number theory to recent advances in applied number theory. It presents the first unified account of the four major areas of application where number theory plays a fundamental role, namely cryptography, coding theory, quasi-Monte Carlo methods, and pseudorandom number generation, allowing the authors to delineate the manifold links and interrelations between these areas.  Number theory, which Carl-Friedrich Gauss famously dubbed the queen of mathematics, has always been considered a very beautiful field of mathematics, producing lovely results and elegant proofs. While only very few real-life applications were known in the past, today number theory can be found in everyday life: in supermarket bar code scanners, in our cars’ GPS systems, in online banking, etc.  Starting with a brief introductory course on number theory in Chapter 1, which makes the book more accessible for undergraduates, the authors describe the four main application areas in Chapters...

  17. Applied systems theory

    CERN Document Server

    Dekkers, Rob

    2017-01-01

    Offering an up-to-date account of systems theories and its applications, this book provides a different way of resolving problems and addressing challenges in a swift and practical way, without losing overview and grip on the details. From this perspective, it offers a different way of thinking in order to incorporate different perspectives and to consider multiple aspects of any given problem. Drawing examples from a wide range of disciplines, it also presents worked cases to illustrate the principles. The multidisciplinary perspective and the formal approach to modelling of systems and processes of ‘Applied Systems Theory’ makes it suitable for managers, engineers, students, researchers, academics and professionals from a wide range of disciplines; they can use this ‘toolbox’ for describing, analysing and designing biological, engineering and organisational systems as well as getting a better understanding of societal problems. This revised, updated and expanded second edition includes coverage of a...

  18. Applied multivariate statistical analysis

    CERN Document Server

    Härdle, Wolfgang Karl

    2015-01-01

    Focusing on high-dimensional applications, this 4th edition presents the tools and concepts used in multivariate data analysis in a style that is also accessible for non-mathematicians and practitioners.  It surveys the basic principles and emphasizes both exploratory and inferential statistics; a new chapter on Variable Selection (Lasso, SCAD and Elastic Net) has also been added.  All chapters include practical exercises that highlight applications in different multivariate data analysis fields: in quantitative financial studies, where the joint dynamics of assets are observed; in medicine, where recorded observations of subjects in different locations form the basis for reliable diagnoses and medication; and in quantitative marketing, where consumers’ preferences are collected in order to construct models of consumer behavior.  All of these examples involve high to ultra-high dimensions and represent a number of major fields in big data analysis. The fourth edition of this book on Applied Multivariate ...

  19. Applied mechanics of solids

    CERN Document Server

    Bower, Allan F

    2009-01-01

    Modern computer simulations make stress analysis easy. As they continue to replace classical mathematical methods of analysis, these software programs require users to have a solid understanding of the fundamental principles on which they are based. Develop Intuitive Ability to Identify and Avoid Physically Meaningless Predictions Applied Mechanics of Solids is a powerful tool for understanding how to take advantage of these revolutionary computer advances in the field of solid mechanics. Beginning with a description of the physical and mathematical laws that govern deformation in solids, the text presents modern constitutive equations, as well as analytical and computational methods of stress analysis and fracture mechanics. It also addresses the nonlinear theory of deformable rods, membranes, plates, and shells, and solutions to important boundary and initial value problems in solid mechanics. The author uses the step-by-step manner of a blackboard lecture to explain problem solving methods, often providing...

  20. Inferring relevance in a changing world

    Directory of Open Access Journals (Sweden)

    Robert C Wilson

    2012-01-01

    Full Text Available Reinforcement learning models of human and animal learning usually concentrate on how we learn the relationship between different stimuli or actions and rewards. However, in real world situations stimuli are ill-defined. On the one hand, our immediate environment is extremely multi-dimensional. On the other hand, in every decision-making scenario only a few aspects of the environment are relevant for obtaining reward, while most are irrelevant. Thus a key question is how do we learn these relevant dimensions, that is, how do we learn what to learn about? We investigated this process of representation learning experimentally, using a task in which one stimulus dimension was relevant for determining reward at each point in time. As in real life situations, in our task the relevant dimension can change without warning, adding ever-present uncertainty engendered by a constantly changing environment. We show that human performance on this task is better described by a suboptimal strategy based on selective attention and serial hypothesis testing rather than a normative strategy based on probabilistic inference. From this, we conjecture that the problem of inferring relevance in general scenarios is too computationally demanding for the brain to solve optimally. As a result the brain utilizes approximations, employing these even in simplified scenarios in which optimal representation learning is tractable, such as the one in our experiment.

  1. Passage relevance models for genomics search

    Directory of Open Access Journals (Sweden)

    Frieder Ophir

    2009-03-01

    Full Text Available Abstract We present a passage relevance model for integrating syntactic and semantic evidence of biomedical concepts and topics using a probabilistic graphical model. Component models of topics, concepts, terms, and document are represented as potential functions within a Markov Random Field. The probability of a passage being relevant to a biologist's information need is represented as the joint distribution across all potential functions. Relevance model feedback of top ranked passages is used to improve distributional estimates of query concepts and topics in context, and a dimensional indexing strategy is used for efficient aggregation of concept and term statistics. By integrating multiple sources of evidence including dependencies between topics, concepts, and terms, we seek to improve genomics literature passage retrieval precision. Using this model, we are able to demonstrate statistically significant improvements in retrieval precision using a large genomics literature corpus.

  2. Applied Linguistics and the "Annual Review of Applied Linguistics."

    Science.gov (United States)

    Kaplan, Robert B.; Grabe, William

    2000-01-01

    Examines the complexities and differences involved in granting disciplinary status to the role of applied linguistics, discusses the role of the "Annual Review of Applied Linguistics" as a contributor to the development of applied linguistics, and highlights a set of publications for the future of applied linguistics. (Author/VWL)

  3. Identity theory and personality theory: mutual relevance.

    Science.gov (United States)

    Stryker, Sheldon

    2007-12-01

    Some personality psychologists have found a structural symbolic interactionist frame and identity theory relevant to their work. This frame and theory, developed in sociology, are first reviewed. Emphasized in the review are a multiple identity conception of self, identities as internalized expectations derived from roles embedded in organized networks of social interaction, and a view of social structures as facilitators in bringing people into networks or constraints in keeping them out, subsequently, attention turns to a discussion of the mutual relevance of structural symbolic interactionism/identity theory and personality theory, looking to extensions of the current literature on these topics.

  4. The relevance of 7-day patch test reading.

    Science.gov (United States)

    Higgins, Eleanor; Collins, Paul

    2013-01-01

    Patch test readings are usually performed on day 2 (48 hours) and day 4 (96 hours). However, reports in the literature identify delayed allergy to metals, corticosteroids, antibiotics, some preservatives, acrylic and methacrylic monomers and p-phenylenediamine. The aim of our study was to identify the benefit of performing a day 7 (168 hours) reading to identify relevant late positive reactions. Two hundred three consecutive patients were patch tested to the British Society for Cutaneous Allergy standard series with additional test series selected according to clinical history and applied at the same time. Twenty-six patients (12.8%) had new positive reactions on day 7 (168 hours), with 28 relevant positive reactions to 21 allergens. These included mercury 0.5% (2/26); cobalt chloride 1% (2/26); colophony 20% (2/26); disperse blue mix 106/124 1% (2/26); preservatives (4/26) that included Methylchloroisothiazolinone/methylisothiazolinone, sodium metabisulfite, and diazolidinyl urea; fragrances (7/26); and gentamycin sulfate 20% (1/26). These results confirm findings in the literature and support the argument for performing a day 7 reading (168 hours) to identify relevant late positive reactions.

  5. Applied hydraulic transients

    CERN Document Server

    Chaudhry, M Hanif

    2014-01-01

    This book covers hydraulic transients in a comprehensive and systematic manner from introduction to advanced level and presents various methods of analysis for computer solution. The field of application of the book is very broad and diverse and covers areas such as hydroelectric projects, pumped storage schemes, water-supply systems, cooling-water systems, oil pipelines and industrial piping systems. Strong emphasis is given to practical applications, including several case studies, problems of applied nature, and design criteria. This will help design engineers and introduce students to real-life projects. This book also: ·         Presents modern methods of analysis suitable for computer analysis, such as the method of characteristics, explicit and implicit finite-difference methods and matrix methods ·         Includes case studies of actual projects ·         Provides extensive and complete treatment of governed hydraulic turbines ·         Presents design charts, desi...

  6. Academic training: Applied superconductivity

    CERN Multimedia

    2007-01-01

    LECTURE SERIES 17, 18, 19 January from 11.00 to 12.00 hrs Council Room, Bldg 503 Applied Superconductivity : Theory, superconducting Materials and applications E. PALMIERI/INFN, Padova, Italy When hearing about persistent currents recirculating for several years in a superconducting loop without any appreciable decay, one realizes that we are dealing with a phenomenon which in nature is the closest known to the perpetual motion. Zero resistivity and perfect diamagnetism in Mercury at 4.2 K, the breakthrough during 75 years of several hundreds of superconducting materials, the revolution of the "liquid Nitrogen superconductivity"; the discovery of still a binary compound becoming superconducting at 40 K and the subsequent re-exploration of the already known superconducting materials: Nature discloses drop by drop its intimate secrets and nobody can exclude that the last final surprise must still come. After an overview of phenomenology and basic theory of superconductivity, the lectures for this a...

  7. Study guide for applied finite mathematics

    CERN Document Server

    Macri, Nicholas A

    1982-01-01

    Study Guide for Applied Finite Mathematics, Third Edition is a study guide that introduces beginners to the fundamentals of finite mathematics and its various realistic and relevant applications. Some applications of probability, game theory, and Markov chains are given. Each chapter includes exercises, and each set begins with basic computational ""drill"" problems and then progresses to problems with more substance.Comprised of 10 chapters, this book begins with exercises related to set theory and concepts such as the union and intersection of sets. Exercises on Cartesian coordinate

  8. Essays in applied microeconomics

    Science.gov (United States)

    Wang, Xiaoting

    In this dissertation I use Microeconomic theory to study firms' behavior. Chapter One introduces the motivations and main findings of this dissertation. Chapter Two studies the issue of information provision through advertisement when markets are segmented and consumers' price information is incomplete. Firms compete in prices and advertising strategies for consumers with transportation costs. High advertising costs contribute to market segmentation. Low advertising costs promote price competition among firms and improves consumer welfare. Chapter Three also investigates market power as a result of consumers' switching costs. A potential entrant can offer a new product bundled with an existing product to compensate consumers for their switching cost. If the primary market is competitive, bundling simply plays the role of price discrimination, and it does not dominate unbundled sales in the process of entry. If the entrant has market power in the primary market, then bundling also plays the role of leveraging market power and it dominates unbundled sales. The market for electric power generation has been opened to competition in recent years. Chapter Four looks at issues involved in the deregulated electricity market. By comparing the performance of the competitive market with the social optimum, we identify the conditions under which market equilibrium generates socially efficient levels of electric power. Chapter Two to Four investigate the strategic behavior among firms. Chapter Five studies the interaction between firms and unemployed workers in a frictional labor market. We set up an asymmetric job auction model, where two types of workers apply for two types of job openings by bidding in auctions and firms hire the applicant offering them the most profits. The job auction model internalizes the determination of the share of surplus from a match, therefore endogenously generates incentives for an efficient division of the matching surplus. Microeconomic

  9. Vygotsky in applied neuropsychology

    Directory of Open Access Journals (Sweden)

    Glozman J. M.

    2016-12-01

    Full Text Available The aims of this paper are: 1 to show the role of clinical experience for the theoretical contributions of L.S. Vygotsky, and 2 to analyze the development of these theories in contemporary applied neuropsychology. An analysis of disturbances of mental functioning is impossible without a systemic approach to the evidence observed. Therefore, medical psychology is fundamental for forming a systemic approach to psychology. The assessment of neurological patients at the neurological hospital of Moscow University permitted L.S. Vygotsky to create, in collaboration with A.R. Luria, the theory of systemic dynamic localization of higher mental functions and their relationship to cultural conditions. In his studies of patients with Parkinson’s disease, Vygotsky also set out 3 steps of systemic development: interpsychological, then extrapsychological, then intrapsychological. L.S. Vygotsky and A.R. Luria in the late 1920s created a program to compensate for the motor subcortical disturbances in Parkinson’s disease (PD through a cortical (visual mediation of movements. We propose to distinguish the objective mediating factors — like teaching techniques and modalities — from subjective mediating factors, like the individual’s internal representation of his/her own disease. The cultural-historical approach in contemporary neuropsychology forces neuropsychologists to re-analyze and re-interpret the classic neuropsychological syndromes; to develop new assessment procedures more in accordance with the patient’s conditions of life; and to reconsider the concept of the social brain as a social and cultural determinant and regulator of brain functioning. L.S. Vygotsky and A.R. Luria proved that a defect interferes with a child’s appropriation of his/her culture, but cultural means can help the child overcome the defect. In this way, the cultural-historical approach became, and still is, a methodological basis for remedial education.

  10. Bible Translation And Relevance Theory | Deist | Stellenbosch ...

    African Journals Online (AJOL)

    Stellenbosch Papers in Linguistics Plus. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 22 (1992) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. Bible Translation And Relevance Theory. F Deist ...

  11. Seeking Relevance: American Political Science and America

    Science.gov (United States)

    Maranto, Robert; Woessner, Matthew C.

    2012-01-01

    In this article, the authors talk about the relevance of American political science and America. Political science has enormous strengths in its highly talented practitioners and sophisticated methods. However, its disconnection from its host society, while not so severe as for fields like English and sociology, nonetheless poses an existential…

  12. Is Enterprise Education Relevant to Social Enterprise?

    Science.gov (United States)

    Bridge, Simon

    2015-01-01

    Purpose: Both enterprise education and social enterprise have become fashionable but what, if any, should be the connections between them? The purpose of this paper is to explore those connections and to reflect on what relevance the two concepts might have for each other. Design/methodology/approach: Both enterprise education and social…

  13. The Relevant Physical Trace in Criminal Investigation

    Directory of Open Access Journals (Sweden)

    Durdica Hazard

    2016-01-01

    Full Text Available A criminal investigation requires the forensic scientist to search and to interpret vestiges of a criminal act that happened in the past. The forensic scientist is one of the many stakeholders who take part in the information quest within the criminal justice system. She reads the investigation scene in search of physical traces that should enable her to tell the story of the offense/crime that allegedly occurred. The challenge for any investigator is to detect and recognize relevant physical traces in order to provide clues for investigation and intelligence purposes, and that will constitute sound and relevant evidence for the court. This article shows how important it is to consider the relevancy of physical traces from the beginning of the investigation and what might influence the evaluation process. The exchange and management of information between the investigation stakeholders are important. Relevancy is a dimension that needs to be understood from the standpoints of law enforcement personnel and forensic scientists with the aim of strengthening investigation and ultimately the overall judicial process.

  14. Interpersonal communication: It's relevance to nursing practice ...

    African Journals Online (AJOL)

    This paper is aimed at highlighting how essential interpersonal communication is necessary for establishing rapport, understanding the needs of the patients and planning effective intervention for meeting holistic health care. To be continually relevant, Nurses have to improve on their communication skills to meet the ...

  15. Inferring feature relevances from metric learning

    DEFF Research Database (Denmark)

    Schulz, Alexander; Mokbel, Bassam; Biehl, Michael

    2015-01-01

    Powerful metric learning algorithms have been proposed in the last years which do not only greatly enhance the accuracy of distance-based classifiers and nearest neighbor database retrieval, but which also enable the interpretability of these operations by assigning explicit relevance weights...

  16. The Relevance of Causal Social Construction

    Directory of Open Access Journals (Sweden)

    Marques Teresa

    2017-02-01

    Full Text Available Social constructionist claims are surprising and interesting when they entail that presumably natural kinds are in fact socially constructed. The claims are interesting because of their theoretical and political importance. Authors like Díaz-León argue that constitutive social construction is more relevant for achieving social justice than causal social construction. This paper challenges this claim. Assuming there are socially salient groups that are discriminated against, the paper presents a dilemma: if there were no constitutively constructed social kinds, the causes of the discrimination of existing social groups would have to be addressed, and understanding causal social construction would be relevant to achieve social justice. On the other hand, not all possible constitutively socially constructed kinds are actual social kinds. If an existing social group is constitutively constructed as a social kind K, the fact that it actually exists as a K has social causes. Again, causal social construction is relevant. The paper argues that (i for any actual social kind X, if X is constitutively socially constructed as K, then it is also causally socially constructed; and (ii causal social construction is at least as relevant as constitutive social construction for concerns of social justice. For illustration, I draw upon two phenomena that are presumed to contribute towards the discrimination of women: (i the poor performance effects of stereotype threat, and (ii the silencing effects of gendered language use.

  17. The economic lot size and relevant costs

    NARCIS (Netherlands)

    Corbeij, M.H.; Jansen, R.A.; Grübström, R.W.; Hinterhuber, H.H.; Lundquist, J.

    1993-01-01

    In many accounting textbooks it is strongly argued that decisions should always be evaluated on relevant costs; that is variable costs and opportunity costs. Surprisingly, when it comes to Economic Order Quantities or Lot Sizes, some textbooks appear to be less straightforward. The question whether

  18. Bootstrapping Visual Categorization with Relevant Negatives

    NARCIS (Netherlands)

    Li, X.; Snoek, C.G.M.; Worring, M.; Koelma, D.; Smeulders, A.W.M.

    Learning classifiers for many visual concepts are important for image categorization and retrieval. As a classifier tends to misclassify negative examples which are visually similar to positive ones, inclusion of such misclassified and thus relevant negatives should be stressed during learning.

  19. Why ritual plant use has ethnopharmacological relevance

    NARCIS (Netherlands)

    Quiroz, Diana; Sosef, Marc; Andel, Van Tinde

    2016-01-01

    Ethnopharmacological relevance Although ritual plant use is now recognised both for its socio-cultural importance and for its contribution to nature conservation, its potential pharmacological effects remain overlooked. Aim of the study Our objective was to see whether ritual plant use could have

  20. The relevance of cosmopolitanism for moral education

    NARCIS (Netherlands)

    Merry, M.S.; de Ruyter, D.J.

    2011-01-01

    In this article we defend a moral conception of cosmopolitanism and its relevance for moral education. Our moral conception of cosmopolitanism presumes that persons possess an inherent dignity in the Kantian sense and therefore they should be recognised as ends-in-themselves. We argue that

  1. Ranking Music Data by Relevance and Importance

    DEFF Research Database (Denmark)

    Ruxanda, Maria Magdalena; Nanopoulos, Alexandros; Jensen, Christian Søndergaard

    2008-01-01

    Due to the rapidly increasing availability of audio files on the Web, it is relevant to augment search engines with advanced audio search functionality. In this context, the ranking of the retrieved music is an important issue. This paper proposes a music ranking method capable of flexibly fusing...

  2. Fast multi-output relevance vector regression

    OpenAIRE

    Ha, Youngmin

    2017-01-01

    This paper aims to decrease the time complexity of multi-output relevance vector regression from O(VM^3) to O(V^3+M^3), where V is the number of output dimensions, M is the number of basis functions, and V

  3. Pragmatic inferences and self-relevant judgments

    DEFF Research Database (Denmark)

    Puente-Diaz, Rogelio; Cavazos Arroyo, Judith; Brem, Alexander

    2016-01-01

    Three studies examined the influence of type of scale on self-relevant judgments and the moderating role of age, prevention, focus, and need for cogni- tion. Participants were randomly assigned to a bipolar or a unipolar scale condition in all three studies. Results from study 1 with a representa...

  4. Making Chemistry Relevant to the Engineering Major

    Science.gov (United States)

    Basu-Dutt, Sharmistha; Slappey, Charles; Bartley, Julie K.

    2010-01-01

    As part of a campus-wide, externally funded project to increase performance in, enthusiasm for, and retention within STEM disciplines, we developed an interdisciplinary, team-taught first-year seminar course. The construction and delivery of this course was designed to show the relevance of selected general chemistry topics such as matter and…

  5. Contingent Attentional Capture by Conceptually Relevant Images

    Science.gov (United States)

    Wyble, Brad; Folk, Charles; Potter, Mary C.

    2013-01-01

    Attentional capture is an unintentional shift of visuospatial attention to the location of a distractor that is either highly salient, or relevant to the current task set. The latter situation is referred to as contingent capture, in that the effect is contingent on a match between characteristics of the stimuli and the task-defined…

  6. The Relevance Aura of Bibliographic Records.

    Science.gov (United States)

    Brooks, Terrence A.

    1997-01-01

    Analyzes relevance assessments of topical descriptors for bibliographic records for two dimensions: (1) a vertical conceptual hierarchy of broad to narrow descriptors, and (2) a horizontal linkage of related terms. The data were analyzed for a semantic distance and semantic direction effect as postulated by the Semantic Distance Model. (Author/LRW)

  7. The Relevance of Cosmopolitanism for Moral Education

    Science.gov (United States)

    Merry, Michael S.; de Ruyter, Doret J.

    2011-01-01

    In this article we defend a moral conception of cosmopolitanism and its relevance for moral education. Our moral conception of cosmopolitanism presumes that persons possess an inherent dignity in the Kantian sense and therefore they should be recognised as ends-in-themselves. We argue that cosmopolitan ideals can inspire moral educators to awaken…

  8. Practical relevance of pattern uniqueness in forensic science.

    Science.gov (United States)

    Jayaprakash, Paul T

    2013-09-10

    Uniqueness being unprovable, it has recently been argued that individualization in forensic science is irrelevant and, probability, as applied for DNA profiles, should be applied for all identifications. Critiques against uniqueness have omitted physical matching, a realistic and tangible individualization that supports uniqueness. Describing case examples illustrating pattern matches including physical matching, it is indicated that individualizations are practically relevant for forensic science as they establish facts on a definitive basis providing firm leads benefitting criminal investigation. As a tenet of forensic identification, uniqueness forms a fundamental paradigm relevant for individualization. Evidence on the indeterministic and stochastic causal pathways of characteristics in patterns available in the related fields of science sufficiently supports the proposition of uniqueness. Characteristics involved in physical matching and matching achieved in patterned evidence existing in the state of nature are not events amenable for counting; instead these are ensemble of visible units occupying the entire pattern area stretching the probability of re-occurrence of a verisimilitude pattern into infinity offering epistemic support to uniqueness. Observational methods are as respectable as instrumental or statistical methods since they are capable of generating results that are tangible and obviously valid as in physical matching. Applying the probabilistic interpretation used for DNA profiles to the other patterns would be unbefitting since these two are disparate, the causal pathways of the events, the loci, in the manipulated DNA profiles being determinable. While uniqueness enables individualizations, it does not vouch for eliminating errors. Instead of dismissing uniqueness and individualization, accepting errors as human or system failures and seeking remedial measures would benefit forensic science practice and criminal investigation. Copyright © 2013

  9. Tomographic diagnosis and relevant aspects of otosclerosis

    International Nuclear Information System (INIS)

    Gaiotti, Juliana Oggioni; Gomes, Natalia Delage; Costa, Ana Maria Doffemond; Villela, Caroline Laurita Batista Couto; Moreira, Wanderval; Diniz, Renata Lopes Furletti Caldeira

    2013-01-01

    A literature review and pictorial essay were developed to discuss the importance of knowing the main findings and locations of otosclerosis at multidetector computed tomography (MDCT). The authors performed a retrospective review of cases of otosclerosis diagnosed in their institution by means of high resolution multidetector computed tomography. Otosclerosis corresponds to otic capsule dysplasia characterized by metabolic derangement of its endochondral layer. Such condition constitutes a relevant cause of sensorineural hearing loss, affecting about 7% to 10% of the general population. The diagnosis is usually clinical, but imaging methods play a significant role in the anatomical detailing, differential diagnosis, surgical planning and evaluation of postoperative complications. Among such methods, the relevance of MDCT is highlighted. Radiologists should be familiar with the MDCT findings of otosclerosis, as well as with the temporal bone anatomy to assist in the appropriate clinical management of this disease. (author)

  10. Tomographic diagnosis and relevant aspects of otosclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Gaiotti, Juliana Oggioni; Gomes, Natalia Delage; Costa, Ana Maria Doffemond; Villela, Caroline Laurita Batista Couto; Moreira, Wanderval; Diniz, Renata Lopes Furletti Caldeira, E-mail: jugaiotti@gmail.com [Hospital Mater Dei-Mater Imagem, Belo Horizonte, MG (Brazil)

    2013-09-15

    A literature review and pictorial essay were developed to discuss the importance of knowing the main findings and locations of otosclerosis at multidetector computed tomography (MDCT). The authors performed a retrospective review of cases of otosclerosis diagnosed in their institution by means of high resolution multidetector computed tomography. Otosclerosis corresponds to otic capsule dysplasia characterized by metabolic derangement of its endochondral layer. Such condition constitutes a relevant cause of sensorineural hearing loss, affecting about 7% to 10% of the general population. The diagnosis is usually clinical, but imaging methods play a significant role in the anatomical detailing, differential diagnosis, surgical planning and evaluation of postoperative complications. Among such methods, the relevance of MDCT is highlighted. Radiologists should be familiar with the MDCT findings of otosclerosis, as well as with the temporal bone anatomy to assist in the appropriate clinical management of this disease. (author)

  11. Is QCD relevant to nuclear physics

    International Nuclear Information System (INIS)

    Thomas, A.W.

    1985-01-01

    A review is given of recent work on baryon structure in a number of QCD-motivated models. After establishing a prima facie case that the quark model should be relevant in a consistent description of the nucleus over a wide range of momentum transfer, the author looks for experimental confirmation. The discussion includes the search for exotic states, for a six quark component of the deuteron, and an up to date report on the interpretation of the EMC effect. (Auth.)

  12. Trade Off Relevance Dan Reliability: Isu Ifrs

    OpenAIRE

    Mahmudah, Hadi

    2013-01-01

    Financial reports containing qualitative characteristic that are useful for usernya.For a long time believed to be the existence of trade off between characteristic of qualitative relevance and reliability. Trade off due to the fact that the use of the method of measurement historical cost and fair value. Trade off occur because of the interests of for the purpose of the preparation of reports on finance. Accountability for the purpose of the measurement of the cost of historical still reliab...

  13. Hydrogen interaction with fusion-relevant materials

    International Nuclear Information System (INIS)

    Caorlin, M.

    1990-01-01

    This paper is an outline of the work carried out at JRC Ispra in the Tritium-materials Interaction Laboratory, on the interaction of gaseous hydrogen with several materials of interest in the field of fusion technology. Experimental work is reported and a concise review of relevant theoretical and numerical supporting activity is given as well. A period of about seven years is covered since 1982. Current work and possible future extensions are also briefly mentioned. 11 figs., 18 refs

  14. Nanostructure symmetry: Relevance for physics and computing

    International Nuclear Information System (INIS)

    Dupertuis, Marc-André; Oberli, D. Y.; Karlsson, K. F.; Dalessi, S.; Gallinet, B.; Svendsen, G.

    2014-01-01

    We review the research done in recent years in our group on the effects of nanostructure symmetry, and outline its relevance both for nanostructure physics and for computations of their electronic and optical properties. The exemples of C3v and C2v quantum dots are used. A number of surprises and non-trivial aspects are outlined, and a few symmetry-based tools for computing and analysis are shortly presented

  15. Nanostructure symmetry: Relevance for physics and computing

    Energy Technology Data Exchange (ETDEWEB)

    Dupertuis, Marc-André; Oberli, D. Y. [Laboratory for Physics of Nanostructure, EPF Lausanne (Switzerland); Karlsson, K. F. [Department of Physics, Chemistry, and Biology (IFM), Linköping University (Sweden); Dalessi, S. [Computational Biology Group, Department of Medical Genetics, University of Lausanne (Switzerland); Gallinet, B. [Nanophotonics and Metrology Laboratory, EPF Lausanne (Switzerland); Svendsen, G. [Dept. of Electronics and Telecom., Norwegian University of Science and Technology, Trondheim (Norway)

    2014-03-31

    We review the research done in recent years in our group on the effects of nanostructure symmetry, and outline its relevance both for nanostructure physics and for computations of their electronic and optical properties. The exemples of C3v and C2v quantum dots are used. A number of surprises and non-trivial aspects are outlined, and a few symmetry-based tools for computing and analysis are shortly presented.

  16. Monochloramine Cometabolism by Nitrifying Biofilm Relevant ...

    Science.gov (United States)

    Recently, biological monochloramine removal (i.e., cometabolism) by a pure culture ammonia–oxidizing bacteria, Nitrosomonas europaea, and a nitrifying mixed–culture have been shown to increase monochloramine demand. Although important, these previous suspended culture batch kinetic experiments were not representative of drinking water distribution systems where bacteria grow predominantly as biofilm attached to pipe walls or sediments and physiological differences may exist between suspension and biofilm growth. Therefore, the current research was an important next step in extending the previous results to investigate monochloramine cometabolism by biofilm grown in annular reactors under drinking water relevant conditions. Estimated monochloramine cometabolism kinetics were similar to those of ammonia metabolism, and monochloramine cometabolism was a significant loss mechanism (25–40% of the observed monochloramine loss). These results demonstrated that monochloramine cometabolism occurred in drinking water relevant nitrifying biofilm; thus, cometabolism may be a significant contribution to monochloramine loss during nitrification episodes in distribution systems. Investigate whether or not nitrifying biofilm can biologically transform monochloramine under drinking water relevant conditions.

  17. Selection of relevant dietary indicators for health.

    Science.gov (United States)

    Steingrímsdóttir, L; Ovesen, L; Moreiras, O; Jacob, S

    2002-05-01

    To define a set of dietary components that are relevant determinants for health in Europe. The selected components are intended to serve as nutrition indicators for health in the European Health Monitoring Programme and, as such, must be limited in number, relevant to health in Europe and practical for all involved countries with respect to data gathering and comparability of data. Major nutrition factors were determined by reviewing relevant epidemiological and clinical literature in nutrition and health as well as referring to reports from international expert groups, including the report from the project Nutrition and Diet for Healthy Lifestyles in Europe. The selection of factors was also based on the relative ease and cost involved for participating countries to obtain comparable and valid data. The selected factors include foods or food groups as well as individual nutrients. Biomarkers are suggested for selected nutrients that pose the greatest difficulty in obtaining valid and comparable data from dietary studies. The following list of diet indicators for health monitoring in Europe was agreed upon by the EFCOSUM group in 2001, in order of priority: vegetables, fruit, bread, fish, saturated fatty acids as percentage of energy (%E), total fat as %E, and ethanol in grams per day. Biomarkers were suggested for the following nutrients: folate, vitamin D, iron, iodine and sodium. Energy has to be assessed in order to calculate %E from total fat and saturated fatty acids.

  18. The value relevance of environmental emissions

    Directory of Open Access Journals (Sweden)

    Melinda Lydia Nelwan

    2016-07-01

    Full Text Available This study examines whether environmental performance has value relevance by investigating the relations between environmental emissions and stock prices for the U.S. public companies. The previous studies argued that the conjectured relations between accounting performance measures and environmental performance do not have a strong theoretical basis, and the modeling of relations between market per-formance measures and environmental performance do not adequately consider the relevance of accounting performance to market value. Therefore, this study examines whether publicly reported environmental emissions provide incremental information to accounting earnings in pricing companies stocks. It is done among the complete set of industries covered by Toxics Release Inventory (TRI reporting for the period 2007 to 2010. Using Ohlson model but modified to include different types of emis-sions, it is found that ground emissions (underground injection and land emissions are value relevant but other emission types (air and water and transferred-out emis-sions appear to not provide incremental information in the valuation model. The result in this study raise concerns that different types of emissions are assessed differently by the market, confirming that studies should not aggregate such measures.

  19. Valerian: No Evidence for Clinically Relevant Interactions

    Directory of Open Access Journals (Sweden)

    Olaf Kelber

    2014-01-01

    Full Text Available In recent popular publications as well as in widely used information websites directed to cancer patients, valerian is claimed to have a potential of adverse interactions with anticancer drugs. This questions its use as a safe replacement for, for example, benzodiazepines. A review on the interaction potential of preparations from valerian root (Valeriana officinalis L. root was therefore conducted. A data base search and search in a clinical drug interaction data base were conducted. Thereafter, a systematic assessment of publications was performed. Seven in vitro studies on six CYP 450 isoenzymes, on p-glycoprotein, and on two UGT isoenzymes were identified. However, the methodological assessment of these studies did not support their suitability for the prediction of clinically relevant interactions. In addition, clinical studies on various valerian preparations did not reveal any relevant interaction potential concerning CYP 1A2, 2D6, 2E1, and 3A4. Available animal and human pharmacodynamic studies did not verify any interaction potential. The interaction potential of valerian preparations therefore seems to be low and thereby without clinical relevance. We conclude that there is no specific evidence questioning their safety, also in cancer patients.

  20. Functional dyspepsia: Are psychosocial factors of relevance?

    Institute of Scientific and Technical Information of China (English)

    Sandra Barry; Timothy G Dinan

    2006-01-01

    The pathogenesis of Functional Dyspepsia (FD) remains unclear, appears diverse and is thus inadequately understood. Akin to other functional gastrointestinal disorders, research has demonstrated an association between this common diagnosis and psychosocial factors and psychiatric morbidity. Conceptualising the relevance of these factors within the syndrome of FD requires application of the biopsychosocial model of disease.Using this paradigm, dysregulation of the reciprocal communication between the brain and the gut is central to symptom generation, interpretation and exacerbation.Appreciation and understanding of the neurobiological correlates of various psychological states is also relevant.The view that psychosocial factors exert their influence in FD predominantly through motivation of health care seeking also persists. This appears too one-dimensional an assertion in light of the evidence available supporting a more intrinsic aetiological link. Evolving understanding of pathogenic mechanisms and the heterogeneous nature of the syndrome will facilitate effective management.Co-morbid psychiatric illness warrants treatment with conventional therapies. Acknowledging the relevance of psychosocial variables in FD, the degree of which is subject to variation, has implications for assessment and management. Available evidence suggests psychological therapies may benefit FD patients particularly those with chronic symptoms. The rationale for use of psychotropic medications in FD is apparent but the evidence base to support the use of antidepressant pharmacotherapy is to date limited.

  1. Morphometrics applied to medical entomology.

    Science.gov (United States)

    Dujardin, Jean-Pierre

    2008-12-01

    Morphometrics underwent a revolution more than one decade ago. In the modern morphometrics, the estimate of size is now contained in a single variable reflecting variation in many directions, as many as there are landmarks under study, and shape is defined as their relative positions after correcting for size, position and orientation. With these informative data, and the corresponding software freely available to conduct complex analyses, significant biological and epidemiological features can be quantified more accurately. We discuss the evolutionary significance of the environmental impact on metric variability, mentioning the importance of concepts like genetic assimilation, genetic accommodation, and epigenetics. We provide examples of measuring the effect of selection on metric variation by comparing (unpublished) Qst values with corresponding (published) Fst. The primary needs of medical entomologists are to distinguish species, especially cryptic species, and to detect them where they are not expected. We explain how geometric morphometrics could apply to these questions, and where there are deficiencies preventing the approach from being utilized at its maximum potential. Medical entomologists in connection with control programs aim to identify isolated populations where the risk of reinfestation after treatment would be low ("biogeographical islands"). Identifying them can be obtained from estimating the number of migrants per generation. Direct assessment of movement remains the most valid approach, but it scores active movement only. Genetic methods estimating gene flow levels among interbreeding populations are commonly used, but gene flow does not necessarily mean the current flow of migrants. Methods using the morphometric variation are neither suited to evaluate gene flow, nor are they adapted to estimate the flow of migrants. They may provide, however, the information needed to create a preliminary map pointing to relevant areas where one could

  2. Making research relevant? Ecological methods and the ecosystem services framework

    Science.gov (United States)

    Root-Bernstein, Meredith; Jaksic, Fabián. M.

    2017-07-01

    We examine some unexpected epistemological conflicts that arise at the interfaces between ecological science, the ecosystem services framework, policy, and industry. We use an example from our own research to motivate and illustrate our main arguments, while also reviewing standard approaches to ecological science using the ecosystem services framework. While we agree that the ecosystem services framework has benefits in its industrial applications because it may force economic decision makers to consider a broader range of costs and benefits than they would do otherwise, we find that many alignments of ecology with the ecosystem services framework are asking questions that are irrelevant to real-world applications, and generating data that does not serve real-world applications. We attempt to clarify why these problems arise and how to avoid them. We urge fellow ecologists to reflect on the kind of research that can lead to both scientific advances and applied relevance to society. In our view, traditional empirical approaches at landscape scales or with place-based emphases are necessary to provide applied knowledge for problem solving, which is needed once decision makers identify risks to ecosystem services. We conclude that the ecosystem services framework is a good policy tool when applied to decision-making contexts, but not a good theory either of social valuation or ecological interactions, and should not be treated as one.

  3. Applied Ethics in Nowadays Society

    OpenAIRE

    Tomita CIULEI

    2013-01-01

    This special issue is dedicated to Nowadays Applied Ethics in Society, and falls in the field of social sciences and humanities, being hosted both theoretical approaches and empirical research in various areas of applied ethics. Applied ethics analyzes of a series of morally concrete situations of social or professional practice in order to make / adopt decisions. In the field of applied ethics are integrated medical ethics, legal ethics, media ethics, professional ethics, environmental ethic...

  4. The Routledge Applied Linguistics Reader

    Science.gov (United States)

    Wei, Li, Ed.

    2011-01-01

    "The Routledge Applied Linguistics Reader" is an essential collection of readings for students of Applied Linguistics. Divided into five sections: Language Teaching and Learning, Second Language Acquisition, Applied Linguistics, Identity and Power and Language Use in Professional Contexts, the "Reader" takes a broad…

  5. The impact of positive, negative and topical relevance feedback

    NARCIS (Netherlands)

    Kaptein, Rianne; Kamps, Jaap; Hiemstra, Djoerd

    2008-01-01

    This document contains a description of experiments for the 2008 Relevance Feedback track. We experiment with different amounts of feedback, including negative relevance feedback. Feedback is implemented using massive weighted query expansion. Parsimonious query expansion using only relevant

  6. THE COMPLEX OF EMOTIONAL EXPERIENCES, RELEVANT MANIFESTATIONS OF INSPIRATION

    Directory of Open Access Journals (Sweden)

    Pavel A. Starikov

    2015-01-01

    Full Text Available The aim of the study is to investigate structure of emotional experiences, relevant manifestations of inspiration creative activities of students.Methods. The proposed methods of mathematical statistics (correlation analysis, factor analysis, multidimensional scaling are applied.Results and scientific novelty. The use of factor analysis, multidimensional scaling allowed to reveal a consistent set of positive experiences of the students, the relevant experience of inspiration in creative activities. «Operational» rueful feelings dedicated by M. Chiksentmihaji («feeling of full involvement, and dilution in what you do», «feeling of concentration, perfect clarity of purpose, complete control and a feeling of total immersion in a job that does not require special efforts» and experiences of the «spiritual» nature, more appropriate to peaks experiences of A. Maslow («feeling of love for all existing, all life»; «a deep sense of self importance, the inner feeling of approval of self»; «feeling of unity with the whole world»; «acute perception of the beauty of the world of nature, “beautiful instant”»; «feeling of lightness, flowing» are included in this complex in accordance with the study results. The interrelation of degree of expressiveness of the given complex of experiences with inspiration experience is considered.Practical significance. The results of the study show structure of emotional experiences, relevant manifestations of inspiration. Research materials can be useful both to psychologists, and experts in the field of pedagogy of creative activity.

  7. Applying Social Capital Theory and the Technology Acceptance ...

    African Journals Online (AJOL)

    Applying Social Capital Theory and the Technology Acceptance Model in information and knowledge sharing research. ... Inkanyiso: Journal of Humanities and Social Sciences ... The paper explains the components, relevance and practical applicability of the two theories to information and knowledge sharing research.

  8. Ethical Perspectives on Qualitative Research in Applied Psychology

    Science.gov (United States)

    Haverkamp, Beth E.

    2005-01-01

    The present article explores ethical issues that emerge in qualitative research conducted by applied psychologists. The utility and relevance of the Ethical Principles of Psychologists and Code of Conduct (American Psychological Association, 2002) for qualitative research are examined. The importance of psychology's fiduciary relationship with…

  9. Bringing the "Folk" into Applied Linguistics: An Introduction

    Science.gov (United States)

    Wilton, Antje; Stegu, Martin

    2011-01-01

    As applied linguistics is mainly concerned with solving the language-related problems of laypeople, the examination of folk views constitutes an important research field and its relevance is illustrated in this issue of the AILA review. In this introductory article, we address some of the more general aspects that need to be considered in the…

  10. The actual relevance of ecological corridors in nature conservation

    Directory of Open Access Journals (Sweden)

    Ćurčić Nina B.

    2013-01-01

    Full Text Available The paper considers theoretical and applied foundations of the concept of the ecological corridors in nature conservation. Their relevance comes from recent ecological phenomenon of habitat fragmentation which is rapidly increasing during last decades. Habitat fragmentation is one of the main threats to richness and diversity of wildlife. Ecological corridors can mitigate the loss and fragmentation of habitat. Corridors perform as “bridges” between habitats for species and they provide a flow of the natural or even anthropogenic caused disturbances. In this paper we will present the meaning and significance of ecological corridors in nature conservation, as well as types of ecological corridors and their ecological benefits. Methodological and practical approaches in nature protection system in Serbia are included. [Projekat Ministarstva nauke Republike Srbije, br. 47007 i br. 176008

  11. Are classical process safety concepts relevant to nanotechnology applications?

    International Nuclear Information System (INIS)

    Amyotte, Paul R

    2011-01-01

    The answer to the question posed by the title of this paper is yes - with adaptation to the specific hazards and challenges found in the field of nanotechnology. The validity of this affirmative response is demonstrated by relating key process safety concepts to various aspects of the nanotechnology industry in which these concepts are either already practised or could be further applied. This is accomplished by drawing on the current author's experience in process safety practice and education as well as a review of the relevant literature on the safety of nanomaterials and their production. The process safety concepts selected for analysis include: (i) risk management, (ii) inherently safer design, (iii) human error and human factors, (iv) safety management systems, and (v) safety culture.

  12. Fusion-relevant basic radiation effects: theory and experiment

    International Nuclear Information System (INIS)

    Mansur, L.K.; Coghlan, W.A.; Farrell, K.; Horton, L.L.; Lee, E.H.; Lewis, M.B.; Packan, N.H.

    1983-01-01

    A summary is given of results of the basic radiation effects program at Oak Ridge National Laboratory, which are relevant to fusion reactor materials applications. The basic radiation effects program at ORNL is a large effort with the dual objectives of understanding the atomic and microstructural defect mechanisms underlying radiation effects and of determining principles for the design of radiation resistant materials. A strength of this effort is the parallel and integrated experimental and theoretical approaches in each major research area. The experimental effort is active in electron microscopy, ion irradiations and ion-beam techniques, neutron irradiations, surface analysis and in other areas. The theoretical effort is active in developing the theory of radiation effects for a broad range of phenomena and in applying it to the design and interpretation of experiments and to alloy design

  13. [G-DRG system 2009: relevant changes for rheumatology].

    Science.gov (United States)

    Fiori, W; Liedtke-Dyong, A; Lakomek, H-J; Buscham, K; Lehmann, H; Liman, W; Fuchs, A-K; Bessler, F; Roeder, N

    2009-08-01

    The following article presents the main general and specific changes in the G-DRG (German diagnosis-related groups) system in terms of the classification systems for diagnoses and procedures as well as the billing process for 2009. Of fundamental relevance is the national weighting of the G-DRG I97Z (complex rheumatologic treatment), which up to now had to be negotiated individually by each hospital. Emphasis is also put on case auditing by the health insurers. Being primarily a tool for redistribution of resources, every hospital has to analyze the economic effects of the 2009 G-DRG system by applying the G-DRG transition grouper to its own cases. Depending on their clinical focus rheumatological departments may experience positive or negative consequences from the development. The strain imposed on hospitals by inadequate refunding of rising costs has to be assessed separately from the effects of redistribution by the G-DRG system.

  14. The relevance of behavioural sciences in dental practice

    DEFF Research Database (Denmark)

    Schou, L

    2000-01-01

    includes compliance with certain oral hygiene regimens or specific dental visiting patterns. The outcome of the treatment depends on both the dental professional's knowledge and skills and the patient's skills, objectives and expectations. Furthermore, dental professionals and patients should be satisfied......The aim of this paper is to illustrate how knowledge from behavioural sciences is necessary and relevant in creating a successful dental practice, benefitting patients and dental professionals. There are many ways to create a successful dental practice, the products of which are the various...... treatments performed by dentists or dental hygienists for their patients. Advanced technologies and methods are constantly improving these treatments and thus the technical and managerial aspects of dentistry. However, the success of dental practice is not only dependent on the technique applied...

  15. Happiness: origins, forms, and technical relevance.

    Science.gov (United States)

    Akhtar, Salman

    2010-09-01

    By critically reviewing Freud's views on happiness, and also those of Helene Deutsch, Bertram Lewin, Melanie Klein, and Heinz Kohut, the author evolves a complex and multilayered perspective on the phenomenon. He categorizes happiness into four related and occasionally overlapping varieties: pleasure-based happiness (elation), assertion-based happiness (joy), merger-based happiness (ecstasy), and fulfillment-based happiness (contentment). After entering some caveats and drawing from his clinical experience, the author then demonstrates the relevance of these ideas to the conduct of psychotherapy and psychoanalysis.

  16. Relevance of physics to the pharmacy major.

    Science.gov (United States)

    McCall, Richard P

    2007-08-15

    To offer a physics course that is relevant to pharmacy students, yet still contains many of the fundamental principles of physics. The course was modified over a period of several years to include activities and examples that were related to other courses in the curriculum. Course evaluations were given to assess student attitudes about the importance of physics in the pharmacy curriculum. Students' attitudes have changed over time to appreciate the role that physics plays in their studies. Students gained confidence in their ability to learn in other courses.

  17. Heuristics for Relevancy Ranking of Earth Dataset Search Results

    Science.gov (United States)

    Lynnes, Christopher; Quinn, Patrick; Norton, James

    2016-01-01

    As the Variety of Earth science datasets increases, science researchers find it more challenging to discover and select the datasets that best fit their needs. The most common way of search providers to address this problem is to rank the datasets returned for a query by their likely relevance to the user. Large web page search engines typically use text matching supplemented with reverse link counts, semantic annotations and user intent modeling. However, this produces uneven results when applied to dataset metadata records simply externalized as a web page. Fortunately, data and search provides have decades of experience in serving data user communities, allowing them to form heuristics that leverage the structure in the metadata together with knowledge about the user community. Some of these heuristics include specific ways of matching the user input to the essential measurements in the dataset and determining overlaps of time range and spatial areas. Heuristics based on the novelty of the datasets can prioritize later, better versions of data over similar predecessors. And knowledge of how different user types and communities use data can be brought to bear in cases where characteristics of the user (discipline, expertise) or their intent (applications, research) can be divined. The Earth Observing System Data and Information System has begun implementing some of these heuristics in the relevancy algorithm of its Common Metadata Repository search engine.

  18. Studies Relevent to Catalytic Activation Co & other small Molecules

    Energy Technology Data Exchange (ETDEWEB)

    Ford, Peter C

    2005-02-22

    Detailed annual and triannual reports describing the progress accomplished during the tenure of this grant were filed with the Program Manager for Catalysis at the Office of Basic Energy Sciences. To avoid unnecessary duplication, the present report will provide a brief overview of the research areas that were sponsored by this grant and list the resulting publications and theses based on this DOE supported research. The scientific personnel participating in (and trained by) this grant's research are also listed. Research carried out under this DOE grant was largely concerned with the mechanisms of the homogeneous catalytic and photocatalytic activation of small molecules such as carbon monoxide, dihydrogen and various hydrocarbons. Much of the more recent effort has focused on the dynamics and mechanisms of reactions relevant to substrate carbonylations by homogeneous organometallic catalysts. A wide range of modern investigative techniques were employed, including quantitative fast reaction methodologies such as time-resolved optical (TRO) and time-resolved infrared (TRIR) spectroscopy and stopped flow kinetics. Although somewhat diverse, this research falls within the scope of the long-term objective of applying quantitative techniques to elucidate the dynamics and understand the principles of mechanisms relevant to the selective and efficient catalytic conversions of fundamental feedstocks to higher value materials.

  19. FIRST experiment: Fragmentation of Ions Relevant for Space and Therapy

    Science.gov (United States)

    Agodi, C.; Abou-Haidar, Z.; Alvarez, M. A. G.; Aumann, T.; Balestra, F.; Battistoni, G.; Bocci, A.; Bohlen, T. T.; Bondì, M.; Boudard, A.; Brunetti, A.; Carpinelli, M.; Cappuzzello, F.; Cavallaro, M.; Carbone, D.; Cirrone, G. A. P.; Cortes-Giraldo, M. A.; Cuttone, G.; De Napoli, M.; Durante, M.; Fernandez-Garcia, J. P.; Finck, C.; Foti, A.; Gallardo, M. I.; Golosio, B.; Iarocci, E.; Iazzi, F.; Ickert, G.; Introzzi, R.; Juliani, D.; Krimmer, J.; Kurz, N.; Labalme, M.; Lavagno, A.; Leifels, Y.; Le Fevre, A.; Leray, S.; Marchetto, F.; Monaco, V.; Morone, M. C.; Nicolosi, D.; Oliva, P.; Paoloni, A.; Patera, V.; Piersanti, L.; Pleskac, R.; Quesada, J. M.; Randazzo, N.; Romano, F.; Rossi, D.; Rosso, V.; Rousseau, M.; Sacchi, R.; Sala, P.; Sarti, A.; Scheidenberger, C.; Schuy, C.; Sciubba, A.; Sfienti, C.; Simon, H.; Sipala, V.; Spiriti, E.; Stuttge, L.; Tropea, S.; Younis, H.

    2013-03-01

    Nuclear fragmentation processes are relevant in different fields of basic research and applied physics and are of particular interest for tumor therapy and for space radiation protection applications. The FIRST (Fragmentation of Ions Relevant for Space and Therapy) experiment at SIS accelerator of GSI laboratory in Darmstadt, has been designed for the measurement of different ions fragmentation cross sections at different energies between 100 and 1000 MeV/nucleon. The experiment is performed by an international collaboration made of institutions from Germany, France, Italy and Spain. The experimental apparatus is partly based on an already existing setup made of the ALADIN magnet, the MUSIC IV TPC, the LAND2 neutron detector and the TOFWALL scintillator TOF system, integrated with newly designed detectors in the interaction Region (IR) around the carbon removable target: a scintillator Start Counter, a Beam Monitor drift chamber, a silicon Vertex Detector and a Proton Tagger for detection of light fragments emitted at large angles (KENTROS). The scientific program of the FIRST experiment started on summer 2011 with the study of the 400 MeV/nucleon 12C beam fragmentation on thin (8mm) carbon target.

  20. Macroscale hydrologic modeling of ecologically relevant flow metrics

    Science.gov (United States)

    Wenger, Seth J.; Luce, Charles H.; Hamlet, Alan F.; Isaak, Daniel J.; Neville, Helen M.

    2010-09-01

    Stream hydrology strongly affects the structure of aquatic communities. Changes to air temperature and precipitation driven by increased greenhouse gas concentrations are shifting timing and volume of streamflows potentially affecting these communities. The variable infiltration capacity (VIC) macroscale hydrologic model has been employed at regional scales to describe and forecast hydrologic changes but has been calibrated and applied mainly to large rivers. An important question is how well VIC runoff simulations serve to answer questions about hydrologic changes in smaller streams, which are important habitat for many fish species. To answer this question, we aggregated gridded VIC outputs within the drainage basins of 55 streamflow gages in the Pacific Northwest United States and compared modeled hydrographs and summary metrics to observations. For most streams, several ecologically relevant aspects of the hydrologic regime were accurately modeled, including center of flow timing, mean annual and summer flows and frequency of winter floods. Frequencies of high and low flows in the summer were not well predicted, however. Predictions were worse for sites with strong groundwater influence, and some sites showed errors that may result from limitations in the forcing climate data. Higher resolution (1/16th degree) modeling provided small improvements over lower resolution (1/8th degree). Despite some limitations, the VIC model appears capable of representing several ecologically relevant hydrologic characteristics in streams, making it a useful tool for understanding the effects of hydrology in delimiting species distributions and predicting the potential effects of climate shifts on aquatic organisms.

  1. FIRST experiment: Fragmentation of Ions Relevant for Space and Therapy

    International Nuclear Information System (INIS)

    Agodi, C; Bondì, M; Cavallaro, M; Carbone, D; Cirrone, G A P; Cuttone, G; Abou-Haidar, Z; Alvarez, M A G; Bocci, A; Aumann, T; Durante, M; Balestra, F; Battistoni, G; Bohlen, T T; Boudard, A; Brunetti, A; Carpinelli, M; Cappuzzello, F; Cortes-Giraldo, M A; Napoli, M De

    2013-01-01

    Nuclear fragmentation processes are relevant in different fields of basic research and applied physics and are of particular interest for tumor therapy and for space radiation protection applications. The FIRST (Fragmentation of Ions Relevant for Space and Therapy) experiment at SIS accelerator of GSI laboratory in Darmstadt, has been designed for the measurement of different ions fragmentation cross sections at different energies between 100 and 1000 MeV/nucleon. The experiment is performed by an international collaboration made of institutions from Germany, France, Italy and Spain. The experimental apparatus is partly based on an already existing setup made of the ALADIN magnet, the MUSIC IV TPC, the LAND2 neutron detector and the TOFWALL scintillator TOF system, integrated with newly designed detectors in the interaction Region (IR) around the carbon removable target: a scintillator Start Counter, a Beam Monitor drift chamber, a silicon Vertex Detector and a Proton Tagger for detection of light fragments emitted at large angles (KENTROS). The scientific program of the FIRST experiment started on summer 2011 with the study of the 400 MeV/nucleon 12C beam fragmentation on thin (8 mm) carbon target.

  2. Interaction of dermatologically relevant nanoparticles with skin cells and skin

    Directory of Open Access Journals (Sweden)

    Annika Vogt

    2014-12-01

    Full Text Available The investigation of nanoparticle interactions with tissues is complex. High levels of standardization, ideally testing of different material types in the same biological model, and combinations of sensitive imaging and detection methods are required. Here, we present our studies on nanoparticle interactions with skin, skin cells, and biological media. Silica, titanium dioxide and silver particles were chosen as representative examples for different types of skin exposure to nanomaterials, e.g., unintended environmental exposure (silica versus intended exposure through application of sunscreen (titanium dioxide or antiseptics (silver. Because each particle type exhibits specific physicochemical properties, we were able to apply different combinations of methods to examine skin penetration and cellular uptake, including optical microscopy, electron microscopy, X-ray microscopy on cells and tissue sections, flow cytometry of isolated skin cells as well as Raman microscopy on whole tissue blocks. In order to assess the biological relevance of such findings, cell viability and free radical production were monitored on cells and in whole tissue samples. The combination of technologies and the joint discussion of results enabled us to look at nanoparticle–skin interactions and the biological relevance of our findings from different angles.

  3. Other relevant papers in physical oceanography

    International Nuclear Information System (INIS)

    Nyffeler, F.

    1989-01-01

    During the past few years, significant progress has occurred in the field of physical oceanography partly as a consequence of developing cooperation and international participation in well-coordinated ocean research programmes. Although these programs were not designed specifically to address CRESP problems, many have proved to be directly relevant to CRESP objectives. For example, MODE, POLYMODE, and Tourbillon were intensive site-specific experiments that included studies of dispersion processes throughout the water column. NOAMP and GME were also site specific, involved the entire water column, and even stressed near-bottom and suspended-sediment processes. Others, (e.g., WOCE) are larger in scope and include extensive observations of the general circulation of entire ocean basins. As a whole, they contribute immensely to improving the data base for exchange and transport processes and thereby for the verification and validation of both regional-scale and general-circulation ocean models. That, in turn, is directly relevant to radiological assessments. Selected papers deriving from experiments such as these are discussed and referenced below

  4. [Terbinafine : Relevant drug interactions and their management].

    Science.gov (United States)

    Dürrbeck, A; Nenoff, P

    2016-09-01

    The allylamine terbinafine is the probably most frequently prescribed systemic antifungal agent in Germany for the treatment of dermatomycoses and onychomycoses. According to the German drug law, terbinafine is approved for patients who are 18 years and older; however, this antifungal agent is increasingly used off-label for treatment of onychomycoses and tinea capitis in children. Terbinafine is associated with only a few interactions with other drugs, which is why terbinafine can generally be used without problems in older and multimorbid patients. Nevertheless, some potential interactions of terbinafine with certain drug substances are known, including substances of the group of antidepressants/antipsychotics and some cardiovascular drugs. Decisive for the relevance of interactions is-along with the therapeutic index of the substrate and the possible alternative degradation pathways-the genetically determined type of metabolism. When combining terbinafine with tricyclic antidepressants or selective serotonin reuptake inhibitors and serotonin/noradrenalin reuptake inhibitors, the clinical response and potential side effects must be monitored. Problematic is the use of terbinafine with simultaneous treatment with tamoxifen. The administration of potent CYP2D6 inhibitors leads to a diminished efficacy of tamoxifen because one of its most important active metabolites-endoxifen-is not sufficiently available. Therefore, combination of tamoxifen and terbinafine should be avoided. In conclusion, the number of substances which are able to cause clinically relevant interactions in case of simultaneously administration with terbinafine is clear and should be manageable in the dermatological office with adequate monitoring.

  5. Relevance of randomised controlled trials in oncology.

    Science.gov (United States)

    Tannock, Ian F; Amir, Eitan; Booth, Christopher M; Niraula, Saroj; Ocana, Alberto; Seruga, Bostjan; Templeton, Arnoud J; Vera-Badillo, Francisco

    2016-12-01

    Well-designed randomised controlled trials (RCTs) can prevent bias in the comparison of treatments and provide a sound basis for changes in clinical practice. However, the design and reporting of many RCTs can render their results of little relevance to clinical practice. In this Personal View, we discuss the limitations of RCT data and suggest some ways to improve the clinical relevance of RCTs in the everyday management of patients with cancer. RCTs should ask questions of clinical rather than commercial interest, avoid non-validated surrogate endpoints in registration trials, and have entry criteria that allow inclusion of all patients who are fit to receive treatment. Furthermore, RCTs should be reported with complete accounting of frequency and management of toxicities, and with strict guidelines to ensure freedom from bias. Premature reporting of results should be avoided. The bar for clinical benefit should be raised for drug registration, which should require publication and review of mature data from RCTs, post-marketing health outcome studies, and value-based pricing. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Physiologically Relevant Prosthetic Limb Movement Feedback for Upper and Lower Extremity Amputees

    Science.gov (United States)

    2016-10-01

    upper arm (elbow movement), Upper leg (knee movement) and lower leg ( ankle movement) to provide a physiologically relevant sense of limb movement...Additionally a BOA cable tensioning system is passed through these plates and anchored to the external surface of the socket. When tension is applied the

  7. Enabling multi-level relevance feedback on PubMed by integrating rank learning into DBMS.

    Science.gov (United States)

    Yu, Hwanjo; Kim, Taehoon; Oh, Jinoh; Ko, Ilhwan; Kim, Sungchul; Han, Wook-Shin

    2010-04-16

    Finding relevant articles from PubMed is challenging because it is hard to express the user's specific intention in the given query interface, and a keyword query typically retrieves a large number of results. Researchers have applied machine learning techniques to find relevant articles by ranking the articles according to the learned relevance function. However, the process of learning and ranking is usually done offline without integrated with the keyword queries, and the users have to provide a large amount of training documents to get a reasonable learning accuracy. This paper proposes a novel multi-level relevance feedback system for PubMed, called RefMed, which supports both ad-hoc keyword queries and a multi-level relevance feedback in real time on PubMed. RefMed supports a multi-level relevance feedback by using the RankSVM as the learning method, and thus it achieves higher accuracy with less feedback. RefMed "tightly" integrates the RankSVM into RDBMS to support both keyword queries and the multi-level relevance feedback in real time; the tight coupling of the RankSVM and DBMS substantially improves the processing time. An efficient parameter selection method for the RankSVM is also proposed, which tunes the RankSVM parameter without performing validation. Thereby, RefMed achieves a high learning accuracy in real time without performing a validation process. RefMed is accessible at http://dm.postech.ac.kr/refmed. RefMed is the first multi-level relevance feedback system for PubMed, which achieves a high accuracy with less feedback. It effectively learns an accurate relevance function from the user's feedback and efficiently processes the function to return relevant articles in real time.

  8. Optimized maintenance concept of safety relevant valves related to ageing management features in nuclear power plants

    International Nuclear Information System (INIS)

    Koring, R.

    2007-01-01

    This paper presents the existing concept in E.ON Kernkraft and its sound application to ageing management issues by focussing on group 2 components such as safety relevant valves. It is demonstrated how the maintenance concept of safety relevant valves is supported by a valve diagnostic system accompanied by an applied procedure to assess the measured results with respect to the required functionality and ageing phenomena. Furthermore this concept has been developed to optimize the existing preventive maintenance of the safety relevant valves by implementing condition oriented aspects derived from the diagnostic results. The main issue of this maintenance concept is to demonstrate the high level of the secured function, reliability and performance of the safety relevant valves within an integrated ageing management. Additionally it offers improvements of all preventive maintenance issues as maintenance periods and the component related volume, spare parts management and costs. (author)

  9. Searchers' relevance judgments and criteria in evaluating Web pages in a learning style perspective

    DEFF Research Database (Denmark)

    Papaeconomou, Chariste; Zijlema, Annemarie F.; Ingwersen, Peter

    2008-01-01

    The paper presents the results of a case study of searcher's relevance criteria used for assessments of Web pages in a perspective of learning style. 15 test persons participated in the experiments based on two simulated work tasks that provided cover stories to trigger their information needs. Two...... learning styles were examined: Global and Sequential learners. The study applied eye-tracking for the observation of relevance hot spots on Web pages, learning style index analysis and post-search interviews to gain more in-depth information on relevance behavior. Findings reveal that with respect to use......, they are statistically insignificant. When interviewed in retrospective the resulting profiles tend to become even similar across learning styles but a shift occurs from instant assessments with content features of web pages replacing topicality judgments as predominant relevance criteria....

  10. Constitutional relevance of atomic energy law

    International Nuclear Information System (INIS)

    Lettow, S.

    1980-01-01

    In a decision publicized on December 20, 1979 the German Federal Constitutional Court rejected a claim of unconstitutionality in connection with the licensing procedure of the Muelheim-Kaerlich Nuclear Power Station currently under construction. This constitutes confirmation, by the 1st Department of the Court, of a decision in 1978 by the 2nd Department about the Kalkar fast breeder power plant, in which the peaceful utilization of nuclear energy had been found to be constitutional. However, the new decision by the Federal Constitutional Court particularly emphasizes the constitutional relevance of the rules of procedure under the Atomic Energy Act and their function with respect to the protection of civil rights. (orig.) [de

  11. Mirror neurons and their clinical relevance.

    Science.gov (United States)

    Rizzolatti, Giacomo; Fabbri-Destro, Maddalena; Cattaneo, Luigi

    2009-01-01

    One of the most exciting events in neurosciences over the past few years has been the discovery of a mechanism that unifies action perception and action execution. The essence of this 'mirror' mechanism is as follows: whenever individuals observe an action being done by someone else, a set of neurons that code for that action is activated in the observers' motor system. Since the observers are aware of the outcome of their motor acts, they also understand what the other individual is doing without the need for intermediate cognitive mediation. In this Review, after discussing the most pertinent data concerning the mirror mechanism, we examine the clinical relevance of this mechanism. We first discuss the relationship between mirror mechanism impairment and some core symptoms of autism. We then outline the theoretical principles of neurorehabilitation strategies based on the mirror mechanism. We conclude by examining the relationship between the mirror mechanism and some features of the environmental dependency syndromes.

  12. The Integrin Receptor in Biologically Relevant Bilayers

    DEFF Research Database (Denmark)

    Kalli, Antreas C.; Róg, Tomasz; Vattulainen, Ilpo

    2017-01-01

    /talin complex was inserted in biologically relevant bilayers that resemble the cell plasma membrane containing zwitterionic and charged phospholipids, cholesterol and sphingolipids to study the dynamics of the integrin receptor and its effect on bilayer structure and dynamics. The results of this study...... demonstrate the dynamic nature of the integrin receptor and suggest that the presence of the integrin receptor alters the lipid organization between the two leaflets of the bilayer. In particular, our results suggest elevated density of cholesterol and of phosphatidylserine lipids around the integrin....../talin complex and a slowing down of lipids in an annulus of ~30 Å around the protein due to interactions between the lipids and the integrin/talin F2–F3 complex. This may in part regulate the interactions of integrins with other related proteins or integrin clustering thus facilitating signal transduction...

  13. PREDICTING RELEVANT EMPTY SPOTS IN SOCIAL INTERACTION

    Institute of Scientific and Technical Information of China (English)

    Yoshiharu MAENO; Yukio OHSAWA

    2008-01-01

    An empty spot refers to an empty hard-to-fill space which can be found in the records of the social interaction, and is the clue to the persons in the underlying social network who do not appear in the records. This contribution addresses a problem to predict relevant empty spots in social interaction. Homogeneous and inhomogeneous networks are studied as a model underlying the social interaction. A heuristic predictor function method is presented as a new method to address the problem. Simulation experiment is demonstrated over a homogeneous network. A test data set in the form of market baskets is generated from the simulated communication. Precision to predict the empty spots is calculated to demonstrate the performance of the presented method.

  14. Mathematical Properties Relevant to Geomagnetic Field Modeling

    DEFF Research Database (Denmark)

    Sabaka, Terence J.; Hulot, Gauthier; Olsen, Nils

    2010-01-01

    be directly measured. In this chapter, the mathematical foundation of global (as opposed to regional) geomagnetic field modeling is reviewed, and the spatial modeling of the field in spherical coordinates is focussed. Time can be dealt with as an independent variable and is not explicitly considered......Geomagnetic field modeling consists in converting large numbers of magnetic observations into a linear combination of elementary mathematical functions that best describes those observations.The set of numerical coefficients defining this linear combination is then what one refers.......The relevant elementary mathematical functions are introduced, their properties are reviewed, and how they can be used to describe the magnetic field in a source-free (such as the Earth’s neutral atmosphere) or source-dense (such as the ionosphere) environment is explained. Completeness and uniqueness...

  15. Mathematical Properties Relevant to Geomagnetic Field Modeling

    DEFF Research Database (Denmark)

    Sabaka, Terence J.; Hulot, Gauthier; Olsen, Nils

    2014-01-01

    be directly measured. In this chapter, the mathematical foundation of global (as opposed to regional) geomagnetic field modeling is reviewed, and the spatial modeling of the field in spherical coordinates is focused. Time can be dealt with as an independent variable and is not explicitly considered......Geomagnetic field modeling consists in converting large numbers of magnetic observations into a linear combination of elementary mathematical functions that best describes those observations. The set of numerical coefficients defining this linear combination is then what one refers....... The relevant elementary mathematical functions are introduced, their properties are reviewed, and how they can be used to describe the magnetic field in a source-free (such as the Earth’s neutral atmosphere) or source-dense (such as the ionosphere) environment is explained. Completeness and uniqueness...

  16. Towards increased policy relevance in energy modeling

    Energy Technology Data Exchange (ETDEWEB)

    Worrell, Ernst; Ramesohl, Stephan; Boyd, Gale

    2003-07-29

    Historically, most energy models were reasonably equipped to assess the impact of a subsidy or change in taxation, but are often insufficient to assess the impact of more innovative policy instruments. We evaluate the models used to assess future energy use, focusing on industrial energy use. We explore approaches to engineering-economic analysis that could help improve the realism and policy relevance of engineering-economic modeling frameworks. We also explore solutions to strengthen the policy usefulness of engineering-economic analysis that can be built from a framework of multi-disciplinary cooperation. We focus on the so-called ''engineering-economic'' (or ''bottom-up'') models, as they include the amount of detail that is commonly needed to model policy scenarios. We identify research priorities for the modeling framework, technology representation in models, policy evaluation and modeling of decision-making behavior.

  17. Climate-relevant monitorings in Germany

    International Nuclear Information System (INIS)

    Metternich, P.

    1993-01-01

    This catalogue contains so-called meta-data; i.e. information on data. For each measuring programme or set of data, users find the address (postal address, telephone, fax-number) of the respective contact person at the beginning of the entry. The catalogue has three parts: Part A is a compilation of monitoring programmes using conventional methods adopted on the ground. Part B contains research programmes or sets of data from the field of remote sensing. In part C, data sets from time series of climate-relevant parameters are described. Section A was additionally structured according so the compartments of the climate system: Atmosphere, hydrosphere, cryosphere, biosphere. (orig./KW) [de

  18. Bacteriophage lambda: early pioneer and still relevant

    Science.gov (United States)

    Casjens, Sherwood R.; Hendrix, Roger W.

    2015-01-01

    Molecular genetic research on bacteriophage lambda carried out during its golden age from the mid 1950's to mid 1980's was critically important in the attainment of our current understanding of the sophisticated and complex mechanisms by which the expression of genes is controlled, of DNA virus assembly and of the molecular nature of lysogeny. The development of molecular cloning techniques, ironically instigated largely by phage lambda researchers, allowed many phage workers to switch their efforts to other biological systems. Nonetheless, since that time the ongoing study of lambda and its relatives have continued to give important new insights. In this review we give some relevant early history and describe recent developments in understanding the molecular biology of lambda's life cycle. PMID:25742714

  19. Reach and Relevance of Prison Research

    Directory of Open Access Journals (Sweden)

    Hilde Tubex

    2015-04-01

    Full Text Available In this contribution I reflect on the changes in the penal landscape and how they impact on prison research. I do this from my experiences as a prison researcher in a variety of roles, in both Europe and Australia. The growing dominance of managerialism has impacted on both corrective services and universities, in ways that have changed the relationship between current prison practices and academically oriented research. Therefore, academics have to question how their contemporary prison research can bridge the emerging gap: how they can not only produce research that adheres to the roots of criminology and provides a base for a rational penal policy, but also how they can develop strategies to get recognition of and funding for this broader contextual work which, although it might not produce results that are immediately identifiable, can be of relevance in indirect ways and in the longer term.

  20. Relevance of protection quantities in medical exposures

    International Nuclear Information System (INIS)

    Pradhan, A.S.

    2008-01-01

    International Commission on Radiological Protection (ICRP) continues to classify the exposures to radiation in three categories; namely 1- occupational exposure, 2- public exposure, and 3- medical exposure. Protection quantities are primarily meant for the regulatory purpose in radiological protection for controlling and limiting stochastic risks in occupational and public exposures. These are based on two basic assumptions of 1- linear no-threshold dose-effect relationship (LNT) at low doses and 2- long-term additivity of low doses. Medical exposure are predominantly delivered to individuals (patients) undergoing diagnostic examinations, interventional procedures and radiation therapy but also include individual caring for or comforting patients incurring exposure and the volunteers of biomedical medical research programmes. Radiation protection is as relevant to occupational and public exposure as to medical exposures except that the dose limits set for the formers are not applicable to medical exposure but reference levels and dose constrains are recommended for diagnostic and interventional medical procedures. In medical institutions, both the occupational and medical exposure takes place. Since the doses in diagnostic examinations are low, it has been observed that not only the protection quantities are often used in such cases but these are extended to estimate the number of cancer deaths due to such practices. One of the striking features of the new ICRP recommendations has been to elaborate the concepts of the dosimetric quantities. The limitation of protection quantities ((Effective dose, E=Σ RT D TR .W T .W R and Equivalent Dose H T =Σ RT D TR .W R ) have been brought out and this has raised a great concern and initiated debates on the use of these quantities in medical exposures. Consequently, ICRP has set a task group to provide more details and the recommendations. It has, therefore, became important to draw the attention of medical physics community

  1. Ecological principles relevant to nuclear war

    International Nuclear Information System (INIS)

    Hutchinson, T.C.; Cropper, W.P. Jr.; Grover, H.D.

    1985-01-01

    The ecological principles outlined are very basic ones; the authors anticipate a readership trained in a broad range of disciplines, including those unfamiliar with the academic discipline of ecology. The authors include substantial discussion on ecophysiology (i.e., the responses of organisms to their environment) because this is relevant to the new understanding of the potential climatic consequences of nuclear war. In particular, the physiological sensitivity of organisms to reduced levels of light and temperature are a key part of the analysis of the potential ecological effects and agricultural effects of nuclear war. Much of the ecological analysis has been organized around major biological units called biomes. The authors describe the biome concept and discuss some of the environmental-climatic factors that are believed to control biome distribution. Emphasis is given to plants because of their controlling influence on ecosystem functions through their role as primary producers. Future reports are needed to address more fully the potential effects on animals. Much more research needs to be done on both plant and animal responses to the types of perturbations possible for the aftermath of a nuclear war. Another important element for analysis of the potential ecological consequences of nuclear war concerns recovery processes. As the post-nuclear war environmental extremes ameliorate, ecological communities in devastated regions would begin to reorganize. It is not possible to predict the course of such a succession precisely, but some principles concerning post-perturbation replacement (such as seed banks and germination), relevant successional patterns, and organism strategies are discussed

  2. Thermochemical data for environmentally-relevant elements

    International Nuclear Information System (INIS)

    Markich, S.J.; Brown, P.L.

    1999-01-01

    This study provides an extensive stability constant (log K) database suitable for calculating the speciation of selected environmentally-relevant elements (H, Na, K, Ca, Mg, Fe, Mn, U, Al Pb, Zn, Cu and cd) in an aqueous system, where a model fulvic acid (comprising aspartic, citric, malonic, salicylic and tricarballylic acids) is used to simulate metal binding by dissolved organic material Stability constants for inorganic metal complexes and minerals were selected primarily from critical literature complications and/or reviews. In contrast, few critically evaluated data were available for metal complexes with aspartic, citric, malonic, salicylic and tricarballylic acids. Consequently, data from original research articles were carefully evaluated and compiled as part of the study, following defined selection criteria. to meet the objective of compiling a comprehensive and reliable database of stability constants, all relevant equilibria and species, ranging from simple binary metal complexes to more complex ternary and even quaternary, metal complexes were included where possible in addition to the selection of stability constants from empirical sources, estimates of stability constants were performed when this could be done reliably, based on the unified theory of metal ion complexation and/or linear tree energy relationships The stability constants are given as common logarithms (logo) in the form required by the HARPHRQ geochemical code and refer to the standard state, i.e 298.15 K (25 deg C), 10 5 Pa (1 atm) and, for all species, infinite dilution (ionic strength = 0 mol L -1 ). In addition to the compilation of stability constant data, an overview is given of geochemical speciation modelling in aqueous systems and available conceptual models of metal binding by humic substances. (authors)

  3. SOCIAL METRICS APPLIED TO SMART TOURISM

    Directory of Open Access Journals (Sweden)

    O. Cervantes

    2016-09-01

    Full Text Available We present a strategy to make productive use of semantically-related social data, from a user-centered semantic network, in order to help users (tourists and citizens in general to discover cultural heritage, points of interest and available services in a smart city. This data can be used to personalize recommendations in a smart tourism application. Our approach is based on flow centrality metrics typically used in social network analysis: flow betweenness, flow closeness and eccentricity. These metrics are useful to discover relevant nodes within the network yielding nodes that can be interpreted as suggestions (venues or services to users. We describe the semantic network built on graph model, as well as social metrics algorithms used to produce recommendations. We also present challenges and results from a prototypical implementation applied to the case study of the City of Puebla, Mexico.

  4. Applied medical image processing a basic course

    CERN Document Server

    Birkfellner, Wolfgang

    2014-01-01

    A widely used, classroom-tested text, Applied Medical Image Processing: A Basic Course delivers an ideal introduction to image processing in medicine, emphasizing the clinical relevance and special requirements of the field. Avoiding excessive mathematical formalisms, the book presents key principles by implementing algorithms from scratch and using simple MATLAB®/Octave scripts with image data and illustrations on an accompanying CD-ROM or companion website. Organized as a complete textbook, it provides an overview of the physics of medical image processing and discusses image formats and data storage, intensity transforms, filtering of images and applications of the Fourier transform, three-dimensional spatial transforms, volume rendering, image registration, and tomographic reconstruction.

  5. Interactive computer programs for applied nutrition education.

    Science.gov (United States)

    Wise, A

    1985-12-01

    DIET2 and DIET3 are programs written for a Dec2050 computer and intended for teaching applied nutrition to students of nutrition, dietetics, home economics, and hotel and institutional administration. DIET2 combines all the facilities of the separate dietary programs already available at Robert Gordon's Institute of Technology into a single package, and extends these to give students a large amount of relevant information about the nutritional balance of foods (including DHSS and NACNE recommendations) prior to choosing them for meals. Students are also helped by the inclusion of typical portion weights. They are presented with an analysis of nutrients and their balance in the menu created, with an easy mechanism for ammendation of the menu and addition of foods which provide the nutrients that are lacking. At any stage the computer can give the proportion of total nutrient provided by each meal. DIET3 is a relatively simple program that displays the nutritional profile of foods and diets semigraphically.

  6. Social Metrics Applied to Smart Tourism

    Science.gov (United States)

    Cervantes, O.; Gutiérrez, E.; Gutiérrez, F.; Sánchez, J. A.

    2016-09-01

    We present a strategy to make productive use of semantically-related social data, from a user-centered semantic network, in order to help users (tourists and citizens in general) to discover cultural heritage, points of interest and available services in a smart city. This data can be used to personalize recommendations in a smart tourism application. Our approach is based on flow centrality metrics typically used in social network analysis: flow betweenness, flow closeness and eccentricity. These metrics are useful to discover relevant nodes within the network yielding nodes that can be interpreted as suggestions (venues or services) to users. We describe the semantic network built on graph model, as well as social metrics algorithms used to produce recommendations. We also present challenges and results from a prototypical implementation applied to the case study of the City of Puebla, Mexico.

  7. Applied complex variables for scientists and engineers

    CERN Document Server

    Kwok, Yue Kuen

    2010-01-01

    This introduction to complex variable methods begins by carefully defining complex numbers and analytic functions, and proceeds to give accounts of complex integration, Taylor series, singularities, residues and mappings. Both algebraic and geometric tools are employed to provide the greatest understanding, with many diagrams illustrating the concepts introduced. The emphasis is laid on understanding the use of methods, rather than on rigorous proofs. Throughout the text, many of the important theoretical results in complex function theory are followed by relevant and vivid examples in physical sciences. This second edition now contains 350 stimulating exercises of high quality, with solutions given to many of them. Material has been updated and additional proofs on some of the important theorems in complex function theory are now included, e.g. the Weierstrass–Casorati theorem. The book is highly suitable for students wishing to learn the elements of complex analysis in an applied context.

  8. Conversation Analysis and Applied Linguistics.

    Science.gov (United States)

    Schegloff, Emanuel A.; Koshik, Irene; Jacoby, Sally; Olsher, David

    2002-01-01

    Offers biographical guidance on several major areas of conversation-analytic work--turn-taking, repair, and word selection--and indicates past or potential points of contact with applied linguistics. Also discusses areas of applied linguistic work. (Author/VWL)

  9. Writing, Literacy, and Applied Linguistics.

    Science.gov (United States)

    Leki, Ilona

    2000-01-01

    Discusses writing and literacy in the domain of applied linguistics. Focus is on needs analysis for literacy acquisition; second language learner identity; longitudinal studies as extensions of identity work; and applied linguistics contributions to second language literacy research. (Author/VWL)

  10. The Rise of Applied Geography.

    Science.gov (United States)

    Philpponneau, Michel

    1981-01-01

    Presents an historical overview of the use of the science of geography for practical purposes. Topics discussed include British schools of geography during the 19th century, contributions of many of the founders of applied geography, forms in which geographical work can be used for practical purposes, and the status of applied geography in various…

  11. Mining Specific and General Features in Both Positive and Negative Relevance Feedback. QUT E-Discovery Lab at the TREC󈧍 Relevance Feedback Track

    Science.gov (United States)

    2009-11-01

    relevance feedback algo- rithm. Four methods, εMap [1], MapA , P10A, and StatAP [2], were used in the track to measure the performance of Phase 2 runs...εMap and StatAP were applied to the runs us- ing the testing set of only ClueWeb09 Category-B, whereas MapA and P10A were applied to those using the...whole ClueWeb09 English set. Because our experiments were based on only ClueWeb09 Category-B, measuring our per- formance by MapA and P10A might not

  12. [Applied ecology: retrospect and prospect].

    Science.gov (United States)

    He, Xingyuan; Zeng, Dehui

    2004-10-01

    Applied ecology is evolved into a principal part of modern ecology that rapidly develops. The major stimulus for the development of applied ecology roots in seeking the solutions for the problems of human populations, resources and environments. Through four decades, the science of applied ecology has been becoming a huge group of disciplines. The future for the applied ecology should concern more with human-influenced and managed ecosystems, and acknowledge humans as the components of ecosystems. Nowadays and in future, the top-priorities in applied ecology should include following fields: sustainable ecosystems and biosphere, ecosystem services and ecological design, ecological assessment of genetically modified organisms, ecology of biological invasions, epidemical ecology, ecological forecasting, ecological process and its control. The authors believe that the comprehensive and active research hotspots coupled some new traits would occur around these fields in foreseeable future.

  13. Conversation Analysis in Applied Linguistics

    DEFF Research Database (Denmark)

    Kasper, Gabriele; Wagner, Johannes

    2014-01-01

    on applied CA, the application of basic CA's principles, methods, and findings to the study of social domains and practices that are interactionally constituted. We consider three strands—foundational, social problem oriented, and institutional applied CA—before turning to recent developments in CA research...... on learning and development. In conclusion, we address some emerging themes in the relationship of CA and applied linguistics, including the role of multilingualism, standard social science methods as research objects, CA's potential for direct social intervention, and increasing efforts to complement CA......For the last decade, conversation analysis (CA) has increasingly contributed to several established fields in applied linguistics. In this article, we will discuss its methodological contributions. The article distinguishes between basic and applied CA. Basic CA is a sociological endeavor concerned...

  14. Applied probability and stochastic processes

    CERN Document Server

    Sumita, Ushio

    1999-01-01

    Applied Probability and Stochastic Processes is an edited work written in honor of Julien Keilson. This volume has attracted a host of scholars in applied probability, who have made major contributions to the field, and have written survey and state-of-the-art papers on a variety of applied probability topics, including, but not limited to: perturbation method, time reversible Markov chains, Poisson processes, Brownian techniques, Bayesian probability, optimal quality control, Markov decision processes, random matrices, queueing theory and a variety of applications of stochastic processes. The book has a mixture of theoretical, algorithmic, and application chapters providing examples of the cutting-edge work that Professor Keilson has done or influenced over the course of his highly-productive and energetic career in applied probability and stochastic processes. The book will be of interest to academic researchers, students, and industrial practitioners who seek to use the mathematics of applied probability i...

  15. Methodology applied to develop the DHIE: applied methodology

    CSIR Research Space (South Africa)

    Herselman, Marlien

    2016-12-01

    Full Text Available This section will address the methodology that was applied to develop the South African Digital Health Innovation Ecosystem (DHIE). Each chapter under Section B represents a specific phase in the methodology....

  16. Applied environmetrics. Simulation applied to the physical environment

    Energy Technology Data Exchange (ETDEWEB)

    Beer, T

    1988-02-01

    Environmetrics is the application of quantitative methods to all aspects of the social and natural environment. This includes forecasting, mathematical modelling, data analysis, and statistics. Applied Environmetrics as a discipline involves the analysis of environmental data through the use of packaged, or specially designed computer software. Two case studies of recent implementations of applied environmetrics within the Australian mining industry are dealt with. 3 figs., 5 refs.

  17. Functionally relevant microsatellites in sugarcane unigenes

    Directory of Open Access Journals (Sweden)

    Singh Nagendra K

    2010-11-01

    Full Text Available Abstract Background Unigene sequences constitute a rich source of functionally relevant microsatellites. The present study was undertaken to mine the microsatellites in the available unigene sequences of sugarcane for understanding their constitution in the expressed genic component of its complex polyploid/aneuploid genome, assessing their functional significance in silico, determining the extent of allelic diversity at the microsatellite loci and for evaluating their utility in large-scale genotyping applications in sugarcane. Results The average frequency of perfect microsatellite was 1/10.9 kb, while it was 1/44.3 kb for the long and hypervariable class I repeats. GC-rich trinucleotides coding for alanine and the GA-rich dinucleotides were the most abundant microsatellite classes. Out of 15,594 unigenes mined in the study, 767 contained microsatellite repeats and for 672 of these putative functions were determined in silico. The microsatellite repeats were found in the functional domains of proteins encoded by 364 unigenes. Its significance was assessed by establishing the structure-function relationship for the beta-amylase and protein kinase encoding unigenes having repeats in the catalytic domains. A total of 726 allelic variants (7.42 alleles per locus with different repeat lengths were captured precisely for a set of 47 fluorescent dye labeled primers in 36 sugarcane genotypes and five cereal species using the automated fragment analysis system, which suggested the utility of designed primers for rapid, large-scale and high-throughput genotyping applications in sugarcane. Pair-wise similarity ranging from 0.33 to 0.84 with an average of 0.40 revealed a broad genetic base of the Indian varieties in respect of functionally relevant regions of the large and complex sugarcane genome. Conclusion Microsatellite repeats were present in 4.92% of sugarcane unigenes, for most (87.6% of which functions were determined in silico. High level of

  18. Early onset depression: the relevance of anxiety.

    Science.gov (United States)

    Parker, G; Wilhelm, K; Asghari, A

    1997-01-01

    The aim of this study was to determine risk factors that may differentiate early onset from late onset depression. A non-clinical cohort that had been assessed from 1978 to 1993 at 5 yearly intervals and that had a high prevalence rate of lifetime depression took part in the study. We established an appropriate age cut-off to distinguish early onset (i.e. before 26 years) of major and of minor depression, and examined the relevance of a number of possible determinants of early onset depression assessed over the life of the study. Despite several dimensional measures of depression, self-esteem and personality being considered, they generally failed (when assessed early in the study) to discriminate subsequent early onset depression, with the exception of low masculinity scores being a weak predictor of major and/or minor depression. Early onset depression was strongly predicted, however, by a lifetime episode of a major anxiety disorder, with generalised anxiety being a somewhat stronger and more consistent predictor than panic disorder, agoraphobia and minor anxiety disorders (ie social phobia, simple phobia). The possibility that anxiety may act as a key predispositional factor to early onset depression and to a greater number of depressive episodes is important in that clinical assessment and treatment of any existing anxiety disorder may be a more efficient and useful strategy than focussing primarily on the depressive disorder.

  19. Top studies relevant to primary care practice.

    Science.gov (United States)

    Perry, Danielle; Kolber, Michael R; Korownyk, Christina; Lindblad, Adrienne J; Ramji, Jamil; Ton, Joey; Allan, G Michael

    2018-04-01

    To summarize 10 high-quality studies from 2017 that have strong relevance to primary care practice. Study selection involved routine literature surveillance by a group of primary care health professionals. This included screening abstracts of important journals and Evidence Alerts, as well as searching the American College of Physicians Journal Club. Topics of the 2017 articles include whether treating subclinical hypothyroidism improves outcomes or symptoms; whether evolocumab reduces cardiovascular disease as well as low-density lipoprotein levels; whether lifestyle interventions reduce medication use in patients with diabetes; whether vitamin D prevents cardiovascular disease, cancer, or upper respiratory tract infections; whether canagliflozin reduces clinical events in patients with diabetes; how corticosteroid injections affect knee osteoarthritis; whether drained abscesses benefit from antibiotic treatment; whether patients with diabetes benefit from bariatric surgery; whether exenatide reduces clinical events in patients with diabetes; and whether tympanostomy tubes affect outcomes in recurrent acute otitis media or chronic otitis media. We provide brief summaries, context where needed, and final recommendations for 10 studies with potential effects on primary care. We also briefly review 5 "runner-up" studies. Research from 2017 produced several high-quality studies in diabetes management. These have demonstrated benefit for alternative therapies and offered evidence not previously available. This year's selection of studies also provided information on a variety of conditions and therapies that are, or might become, more common in primary care settings. Copyright© the College of Family Physicians of Canada.

  20. Clinically Relevant Anticancer Polymer Paclitaxel Therapeutics

    Directory of Open Access Journals (Sweden)

    Danbo Yang

    2010-12-01

    Full Text Available The concept of utilizing polymers in drug delivery has been extensively explored for improving the therapeutic index of small molecule drugs. In general, polymers can be used as polymer-drug conjugates or polymeric micelles. Each unique application mandates its own chemistry and controlled release of active drugs. Each polymer exhibits its own intrinsic issues providing the advantage of flexibility. However, none have as yet been approved by the U.S. Food and Drug Administration. General aspects of polymer and nano-particle therapeutics have been reviewed. Here we focus this review on specific clinically relevant anticancer polymer paclitaxel therapeutics. We emphasize their chemistry and formulation, in vitro activity on some human cancer cell lines, plasma pharmacokinetics and tumor accumulation, in vivo efficacy, and clinical outcomes. Furthermore, we include a short review of our recent developments of a novel poly(L-g-glutamylglutamine-paclitaxel nano-conjugate (PGG-PTX. PGG-PTX has its own unique property of forming nano-particles. It has also been shown to possess a favorable profile of pharmacokinetics and to exhibit efficacious potency. This review might shed light on designing new and better polymer paclitaxel therapeutics for potential anticancer applications in the clinic.