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Sample records for compact reversed shear

  1. Drift Wave Test Particle Transport in Reversed Shear Profile

    International Nuclear Information System (INIS)

    Horton, W.; Park, H.B.; Kwon, J.M.; Stronzzi, D.; Morrison, P.J.; Choi, D.I.

    1998-01-01

    Drift wave maps, area preserving maps that describe the motion of charged particles in drift waves, are derived. The maps allow the integration of particle orbits on the long time scale needed to describe transport. Calculations using the drift wave maps show that dramatic improvement in the particle confinement, in the presence of a given level and spectrum of E x B turbulence, can occur for q(r)-profiles with reversed shear. A similar reduction in the transport, i.e. one that is independent of the turbulence, is observed in the presence of an equilibrium radial electric field with shear. The transport reduction, caused by the combined effects of radial electric field shear and both monotonic and reversed shear magnetic q-profiles, is also investigated

  2. Shear heating by translational brittle reverse faulting along a single ...

    Indian Academy of Sciences (India)

    Increase in temperature (Ti) of faulted hangingwall and footwall blocks by frictional/shear heating for planar rough reverse faults is proportional to the coefficient of friction (μ), density and thickness of the hangingwall block (ρ). Ti increases as movement progresses with time. Thermal conductivity (Ki) and thermal diffusivity ...

  3. Experimental investigations into the shear behavior of self-compacting RC beams with and without shear reinforcement

    Directory of Open Access Journals (Sweden)

    Ammar N. HANOON

    2014-12-01

    Full Text Available Self-compacting concrete (SCC is a new generation of high-performance concrete, known for its excellent deformability and high resistance to segregation and bleeding. Nonetheless, SCC may be incapable of resisting shear because the shear resistance mechanisms of this concrete are uncertain, especially the aggregate interlock mechanism. This uncertainty is attributed to the fact that SCC contains a smaller amount of coarse aggregates than normal concrete (NC does. This study focuses on the shear strength of self-compacting reinforced concrete (RC beams with and without shear reinforcement. A total of 16 RC beam specimens was manufactured and tested in terms of shear span-to-depth ratio and flexural and shear reinforcement ratio. The test results were compared with those of the shear design equations developed by ACI, BS, CAN and NZ codes. Results show that an increase in web reinforcement enhanced cracking strength and ultimate load. Shear-tension failure was the control failure in all tested beams.

  4. Compact Reversed-Field Pinch Reactors (CRFPR): preliminary engineering considerations

    Energy Technology Data Exchange (ETDEWEB)

    Hagenson, R.L.; Krakowski, R.A.; Bathke, C.G.; Miller, R.L.; Embrechts, M.J.; Schnurr, N.M.; Battat, M.E.; LaBauve, R.J.; Davidson, J.W.

    1984-08-01

    The unique confinement physics of the Reversed-Field Pinch (RFP) projects to a compact, high-power-density fusion reactor that promises a significant reduction in the cost of electricity. The compact reactor also promises a factor-of-two reduction in the fraction of total cost devoted to the reactor plant equipment (i.e., fusion power core (FPC) plus support systems). In addition to operational and developmental benefits, these physically smaller systems can operate economically over a range of total power output. After giving an extended background and rationale for the compact fusion approaches, key FPC subsystems for the Compact RFP Reactor (CRFPR) are developed, designed, and integrated for a minimum-cost, 1000-MWe(net) system. Both the problems and promise of the compact, high-power-density fusion reactor are quantitatively evaluated on the basis of this conceptual design. The material presented in this report both forms a framework for a broader, more expanded conceptual design as well as suggests directions and emphases for related research and development.

  5. Compact Reversed-Field Pinch Reactors (CRFPR): preliminary engineering considerations

    International Nuclear Information System (INIS)

    Hagenson, R.L.; Krakowski, R.A.; Bathke, C.G.; Miller, R.L.; Embrechts, M.J.; Schnurr, N.M.; Battat, M.E.; LaBauve, R.J.; Davidson, J.W.

    1984-08-01

    The unique confinement physics of the Reversed-Field Pinch (RFP) projects to a compact, high-power-density fusion reactor that promises a significant reduction in the cost of electricity. The compact reactor also promises a factor-of-two reduction in the fraction of total cost devoted to the reactor plant equipment [i.e., fusion power core (FPC) plus support systems]. In addition to operational and developmental benefits, these physically smaller systems can operate economically over a range of total power output. After giving an extended background and rationale for the compact fusion approaches, key FPC subsystems for the Compact RFP Reactor (CRFPR) are developed, designed, and integrated for a minimum-cost, 1000-MWe(net) system. Both the problems and promise of the compact, high-power-density fusion reactor are quantitatively evaluated on the basis of this conceptual design. The material presented in this report both forms a framework for a broader, more expanded conceptual design as well as suggests directions and emphases for related research and development

  6. Machine to compact fuel assemblies and to shear out the end parts

    International Nuclear Information System (INIS)

    Auchapt, P.; Sablier, R.; Symard, J.; Seyfried, P.

    1983-01-01

    The present machine allows a simultaneous compaction of the fuel assemblies and the separation of their end parts; the machine compacts the protection structures of the fuel without deforming them and ensures the evacuation of the end parts out of the shears, what allows to consider them apart from α wastes. The present machine accepts fuel assemblies of different length [fr

  7. Conceptual design of economic compact reversed shear Tokamak (CRST)

    International Nuclear Information System (INIS)

    Okano, Kunihiko

    1998-01-01

    Two indices of performance for economic analysis of Tokamak are defined as toroidal β value: β t (%)=(plasma pressure)/(pressure of magnetic field) and Troyon coefficient β N . The pressure of magnetic field is defined as β t 2 /2μ 0 (Bt: strength of toroidal magnetic field and μ 0 : permeability). β N is determined in order to make possible compare β t between other devices. To increase β N is very important on the economic viewpoint. ITER is designed as 2.2 β N , 1 MW/m 2 average neutron wall load, 8.14 m large radius and 2.8 m small radius, but the above values of CRST are 5.5, 4.5 MW/m 2 , 5.4 m and 1.59 m, respectively. Development of industrial and physical technologies makes possible to minimize economic Tokamak. After ITER, we expect that economic fusion reactor is obtained by minimization. CRST satisfies the conditions of economic fusion reactor conduced by the economic analysis. CRST is designed as 5.4 m main radius and 116x10 4 kW electric output. Fundamental physics and technologies, conceptual and industrial design of CRST are explained. (S.Y.)

  8. Effect of cohesion on local compaction and granulation of sheared soft granular materials

    NARCIS (Netherlands)

    Roy, Sudeshna; Luding, Stefan; Weinhart, Thomas

    2017-01-01

    This paper results from an ongoing investigation of the effect of cohesion on the compaction of sheared soft wet granular materials. We compare dry non-cohesive and wet moderately-to-strongly cohesive soft almost frictionless granular materials and report the effect of cohesion between the grains on

  9. Effect of cohesion on local compaction and granulation of sheared soft granular materials

    Directory of Open Access Journals (Sweden)

    Roy Sudeshna

    2017-01-01

    Full Text Available This paper results from an ongoing investigation of the effect of cohesion on the compaction of sheared soft wet granular materials. We compare dry non-cohesive and wet moderately-to-strongly cohesive soft almost frictionless granular materials and report the effect of cohesion between the grains on the local volume fraction. We study this in a three dimensional, unconfined, slowly sheared split-bottom ring shear cell, where materials while sheared are subject to compression under the confining weight of the material above. Our results show that inter-particle cohesion has a considerable impact on the compaction of soft materials. Cohesion causes additional stresses, due to capillary forces between particles, leading to an increase in volume fraction due to higher compaction. This effect is not visible in a system of infinitely stiff particles. In addition, acting oppositely, we observe a general decrease in volume fraction due to increased cohesion for frictional particle, which we attribute to the role of contact friction that enhances dilation.

  10. Global gyrokinetic simulations of toroidal electron temperature gradient driven mode in reversed shear tokamaks

    International Nuclear Information System (INIS)

    Idomura, Y.; Tokuda, S.; Kishimoto, Y.

    2005-01-01

    Using a global gyrokinetic toroidal particle code, the toroidal electron temperature gradient driven (ETG) turbulence is studied in positive and reversed shear tokamaks. In the positive shear configuration, the ETG mode shows a ballooning structure, and its envelope width Δr/ρ te , which is limited by a global ω te *-shearing effect, is proportional to ρ* -1/2 , where ω te * is the electron diamagnetic frequency and ρ* is the electron Larmor radius ρ te divided by the minor radius a. In the reversed shear configuration, the mode width of a slab like ETG mode, which is determined by a global magnetic field structure around the q min surface, does not depend on ρ*. According to the mixing length theory, a ballooning mode gives a Bohm like ρ*-scaling, while a slab like mode shows a gyro-Bohm like ρ*-scaling. In realistic small ρ* tokamaks, the saturation level of the ETG mode in the positive shear configuration is order of magnitude higher than that in the reversed shear configuration. In the nolinear turbulent state, the ETG turbulence in the positive and reversed shear configurations show quite different structure formations. In the positive shear configuration, the ETG turbulence is dominated by streamers which have a ballooning type structure, and the electron temperature T e profile is quickly relaxed to the marginally stable state in a turbulent time scale. In the reversed shear configuration, quasi-steady zonal flows are produced in the negative shear region, while the positive shear region is characterized by streamers. Accordingly, the electron thermal diffusivity χ e has a gap structure across the q min surface, and the T e gradient is sustained above the marginal value for a long time in the quasi-steady phase. The results suggest a stiffness of the T e profile in positive shear tokamaks, and a possibility of the T e transport barrier in reversed shear tokamaks. (author)

  11. The response of dense dry granular material to the shear reversal

    Science.gov (United States)

    Zhang, Jie; Ren, Jie; Farhadi, Somayeh; Behringer, Robert

    2008-11-01

    We have performed two dimensional granular experiments under pure shear using bidisperse photo-elastic disks. Starting from a stress free state, a square box filled with granular particles is subject to shear. The forward shears involved various number of steps, leading to maximum strains between 0.1 and 0.3. The area is kept constant during the shear. The network of force chains gradually built up as the strain increased, leading to increased pressure and shear stress. Reverse shear was then applied to the system. Depending on the initial packing fraction and the strain at which the shear is reversed, the force chain network built prior to the shear reversal may be destroyed completely or partially destroyed. Following the force chain weakening, when the reserve shear is continuously applied to the system, there is a force chain strengthening. Following each change of the system, contact forces of individual disks were measured by applying an inverse algorithm. We also kept track of the displacement and angle of rotation of every particle from frame to frame. We present the results for the structure failure and reconstruction during shear reversals. We also present data for stresses, contact force distributions and other statistical measures.

  12. Rational load rating of deck-girder bridges with girder end shear cracks in reverse orientation.

    Science.gov (United States)

    2017-04-01

    Reverse diagonal shear cracking at reinforced concrete girder supports affects many low-volume bridges built : in the early 1900s in Kansas. This phenomenon, however, is not addressed in the American Association of State : Highway and Transportation ...

  13. Calculations of alpha particle loss for reversed magnetic shear in the Tokamak Fusion Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Redi, M.H.; White, R.B.; Batha, S.H.; Levinton, F.M.; McCune, D.C.

    1997-03-01

    Hamiltonian coordinate, guiding center code calculations of the toroidal field ripple loss of alpha particles from a reversed shear plasma predict both total alpha losses and ripple diffusion losses to be greater than those from a comparable non-reversed magnetic shear plasma in the Tokamak Fusion Test Reactor (TFTR) [Fusion Technol. 21, 1324 (1992)]. High central q is found to increase alpha ripple losses as well as first orbit losses of alphas in the reversed shear simulations. A simple ripple loss model, benchmarked against the guiding center code, is found to work satisfactorily in transport analysis modelling of reversed and monotonic shear scenarios. Alpha ripple transport on TFTR affects ions within r/a=0.5, not at the plasma edge. The entire plasma is above threshold for stochastic ripple loss of alpha particles at birth energy in the reversed shear case simulated, so that all trapped 3.5 MeV alphas are lost stochastically or through prompt losses. The 40% alpha particle loss predictions for TFTR suggest that reduction of toroidal field ripple will be a critical issue in the design of a reversed shear fusion reactor.

  14. Synergistic effects of the safety factor and shear flows on development of internal transport barriers in reversed shear plasmas

    International Nuclear Information System (INIS)

    Wang, A.K.; Dong, J.Q.; Qu, W.X.; Qiu, X.M.

    2002-01-01

    A new suppression mechanism of turbulent transport, characteristic of the synergism between safety factor and shear flows, is proposed to explain the internal transport barriers (ITBs) observed in neutral-beam-heated tokamak discharges with reversed magnetic shear. It is shown that the evolution of turbulent transport with the strength of the suppression mechanism reproduces the basic features of the formation and development of ITBs observed in experiments. In addition, the present analyses predict the possibility of global ion and electron heat transport barriers

  15. ''Compact'' reversed-field pinch (CRFP) reactor design

    International Nuclear Information System (INIS)

    Miley, G.H.; Nebel, R.A.

    1980-01-01

    These results indicate that a CRFP operating in the range of 100 MWe should be feasible. While the large aspect ratio leads to a 6.4-m major radius, the design still retains many attributes of conventional compact tori, such as simplicity and ease of access. The relatively low Q/sub p/ with batch burns might be satifactory for a demonstration unit. However, to obtain power-plant ''grade'' Q/sub p/, either refueling (possibly by pellets) or larger size plasmas appear necessary

  16. Measured temperature and pressure dependence of compressional (Vp) and shear (Vs) wave speeds in compacted, polycrystalline ice lh

    Science.gov (United States)

    Helgerud, M.B.; Waite, W.F.; Kirby, S.H.; Nur, A.

    2003-01-01

    We report on laboratory measurements of compressional- and shear-wave speeds in a compacted, polycrystalline ice-Ih sample. The sample was made from triply distilled water that had been frozen into single crystal ice, ground into small grains, and sieved to extract the 180–250 µm diameter fraction. Porosity was eliminated from the sample by compacting the granular ice between a hydraulically driven piston and a fixed end plug, both containing shear-wave transducers. Based on simultaneous compressional- and shear-wave-speed measurements, we calculated Poisson's ratio and compressional-wave, bulk, and shear moduli from –20 to –5°C and 22 to 33 MPa.

  17. Strain reversal in simple shear extrusion (SSE) processing: Microstructure investigations and mechanical properties

    Science.gov (United States)

    Bagherpour, Ebad; Qods, Fathallah; Ebrahimi, Ramin; Miyamoto, Hiroyuki

    2018-01-01

    Simple shear extrusion (SSE) is one of the severe plastic deformations which are based on the direct extrusion of the samples. By passing the material through the deformation channel, gradually increased shear strain is imposed to the material. The direction of the shear is reversed at the middle of the channel after the maximum distortion angle is achieved. Therefore, the change in the direction of the shear affects the microstructure and texture of the sample in a unique way. Hence, in the present search role of shear reversal on microstructure and mechanical properties of pure copper after multi passes and during a single pass of the simple shear extrusion (SSE) process was investigated. For SSE processing an appropriate die with a linear die profile was designed and constructed. Transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) were used to evaluate the microstructure of the deformed samples. Strain reversal during the process results in a slight reduction in dislocation density, the hardness and mean disorientation angle of the samples, and an increase in the grain size. Strain softening happens as a result of the reduction in the dislocation density and strain induced grain growth. Also, a decrease in hardness and yield strength and an increase in the uniform elongation are observed after softening. Two stages for softening were observed. First, at the middle of the deformation channel in each passes of SSE and second after eight passes of SSE. The mechanism for the latter is the stress coupled grain-boundary migration while the former happens as a result of shear reversal.

  18. Compact and field-portable 3D printed shearing digital holographic microscope for automated cell identification.

    Science.gov (United States)

    Rawat, Siddharth; Komatsu, Satoru; Markman, Adam; Anand, Arun; Javidi, Bahram

    2017-03-20

    We propose a low-cost, compact, and field-portable 3D printed holographic microscope for automated cell identification based on a common path shearing interferometer setup. Once a hologram is captured from the portable setup, a 3D reconstructed height profile of the cell is created. We extract several morphological cell features from the reconstructed 3D height profiles, including mean physical cell thickness, coefficient of variation, optical volume (OV) of the cell, projected area of the cell (PA), ratio of PA to OV, cell thickness kurtosis, cell thickness skewness, and the dry mass of the cell for identification using the random forest (RF) classifier. The 3D printed prototype can serve as a low-cost alternative for the developing world, where access to laboratory facilities for disease diagnosis are limited. Additionally, a cell phone sensor is used to capture the digital holograms. This enables the user to send the acquired holograms over the internet to a computational device located remotely for cellular identification and classification (analysis). The 3D printed system presented in this paper can be used as a low-cost, stable, and field-portable digital holographic microscope as well as an automated cell identification system. To the best of our knowledge, this is the first research paper presenting automatic cell identification using a low-cost 3D printed digital holographic microscopy setup based on common path shearing interferometry.

  19. The effect of toroidal plasma rotation on low-frequency reversed shear Alfven eigenmodes in tokamaks

    NARCIS (Netherlands)

    Haverkort, J. W.

    2012-01-01

    The influence of toroidal plasma rotation on the existence of reversed shear Alfven eigenmodes (RSAEs) near their minimum frequency is investigated analytically. An existence condition is derived showing that a radially decreasing kinetic energy density is unfavourable for the existence of RSAEs.

  20. Lower hybrid heating and current drive in ignitor shear reversal scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Barbato, E.; Pinaccione, L. [Italian Agengy for New Technologies, Energy and the Environment, Centro Ricerche Frascati, Rome (Italy). Dip. Energia

    1996-05-01

    Injection of Lower Hybrid (LH) Wave power at 8 GHz is considered into IGNITOR shear reversal scenarios, characterized by a reduced plasma current and density. Power deposition calculation are performed to establish whether LH waves can be used both as central heating and off axis current drive tool. It turns out that LH waves can be used (a) for central plasma heating purpose during the current vamp phase, to freeze the shear reversed configuration, at the power level of {approx}10 MW. (b) to drive a current in the outer part of the plasma at the power level of 20 MW. In this way around 1/3-1/6 of the total current in the proper plasma position (i.e. where q is minimum) is driven.

  1. Using nanocomposite materials technology to understand and control reverse osmosis membrane compaction

    KAUST Repository

    Pendergast, Mary Theresa M.

    2010-10-01

    Composite reverse osmosis (RO) membranes were formed by interfacial polymerization of polyamide thin films over pure polysulfone and nanocomposite-polysulfone support membranes. Nanocomposite support membranes were formed from amorphous non-porous silica and crystalline microporous zeolite nanoparticles. For each hand-cast membrane, water flux and NaCl rejection were monitored over time at two different applied pressures. Nanocomposite-polysulfone supported RO membranes generally had higher initial permeability and experienced less flux decline due to compaction than pure polysulfone supported membranes. In addition, observed salt rejection tended to increase as flux declined from compaction. Crosssectional SEM images verified significant reduction in thickness of pure polysulfone supports, whereas nanocomposites better resisted compaction due to enhanced mechanical stability imparted by the nanoparticles. A conceptual model was proposed to explain the mechanistic relationship between support membrane compaction and observed changes in water flux and salt rejection. As the support membrane compacts, skin layer pore constriction increased the effective path length for diffusion through the composite membranes, which reduced both water and salt permeability identically. However, experimental salt permeability tended to decline to a greater extent than water permeability; hence, the observed changes in flux and rejection might also be related to structural changes in the polyamide thin film. © 2010 Elsevier B.V. All rights reserved.

  2. Compact-Toroid Fusion Reactor (CTOR) based on the Field-Reversed Theta Pinch

    International Nuclear Information System (INIS)

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

    1981-01-01

    Scoping studies of a translating Compact Torus Reactor (CTOR) have been made on the basis of a dynamic plasma model and an overall systems approach. This CTOR embodiment uses a Field-Reversed Theta Pinch as a plasma source. The field-reversed plasmoid would be formed and compressionally heated to ignition prior to injection into and translation through a linear burn chamber, thereby removing the high-technology plamoid source from the hostile reactor environment. Stabilization of the field-reversed plasmoid would be provided by a passive conducting shell located outside the high-temperature blanket but within the low-field superconducting magnets and associated radition shielding. On the basis of this batch-burn but thermally steady-state approach, a reactor concept emerges with a length below approx. 40 m that generates 300 to 400 MWe of net electrical power with a recirculating power fraction less than 0.15

  3. Characteristics of internal transport barrier in JT-60U reversed shear plasmas

    International Nuclear Information System (INIS)

    Sakamoto, Y.; Kamada, Y.; Ide, S.; Fujita, T.; Shirai, H.; Takizuka, T.; Koide, Y.; Fukuda, T.; Oikawa, T.; Suzuki, T.; Shinohara, K.; Yoshino, R.

    2001-01-01

    Characteristics of internal transport barrier (ITB) structure are studied and the active ITB control has been developed in JT-60U reversed shear plasmas. The following results are found. Outward propagation of the ITB with steep T i gradient is limited to the minimum safety factor location (ρ qmin ). However the ITB with reduced T i gradient can move to the outside of ρ qmin . Lower boundary of ITB width is proportional to the ion poloidal gyroradius at the ITB center. Furthermore the demonstration of the active control of the ITB strength based on the modification of the radial electric field shear profile is successfully performed by the toroidal momentum injection in different directions or the increase of heating power by neutral beams. (author)

  4. Steady shear rheometry of dissipative particle dynamics models of polymer fluids in reverse Poiseuille flow.

    Science.gov (United States)

    Fedosov, Dmitry A; Karniadakis, George Em; Caswell, Bruce

    2010-04-14

    Polymer fluids are modeled with dissipative particle dynamics (DPD) as undiluted bead-spring chains and their solutions. The models are assessed by investigating their steady shear-rate properties. Non-Newtonian viscosity and normal stress coefficients, for shear rates from the lower to the upper Newtonian regimes, are calculated from both plane Couette and plane Poiseuille flows. The latter is realized as reverse Poiseuille flow (RPF) generated from two Poiseuille flows driven by uniform body forces in opposite directions along two-halves of a computational domain. Periodic boundary conditions ensure the RPF wall velocity to be zero without density fluctuations. In overlapping shear-rate regimes the RPF properties are confirmed to be in good agreement with those calculated from plane Couette flow with Lees-Edwards periodic boundary conditions (LECs), the standard virtual rheometer for steady shear-rate properties. The concentration and the temperature dependence of the properties of the model fluids are shown to satisfy the principles of concentration and temperature superposition commonly employed in the empirical correlation of real polymer-fluid properties. The thermodynamic validity of the equation of state is found to be a crucial factor for the achievement of time-temperature superposition. With these models, RPF is demonstrated to be an accurate and convenient virtual rheometer for the acquisition of steady shear-rate rheological properties. It complements, confirms, and extends the results obtained with the standard LEC configuration, and it can be used with the output from other particle-based methods, including molecular dynamics, Brownian dynamics, smooth particle hydrodynamics, and the lattice Boltzmann method.

  5. FIREBIRD - a conceptual design of a field reversed configuration compact torus fusion reactor (CTFR)

    International Nuclear Information System (INIS)

    Raman, R.; Zubrin, R.M.

    1987-01-01

    This paper is a summary of the work carried out by the Nuclear Engineering 512 design team at the University of Washington on a conceptual design study of a Compact-Torus (Field-Reversed) Fusion Reactor Configuration (CTFR). The primary objective of the study was to develop a reactor design that strived for high engineering power density, modest recirculating power and competitive cost of electrical power. A Conceptual design was developed for a translating field-reversed configuration reactor; based on the Physics developed by Tuszewski and Lindford at LANL and by Hoffman and Milroy at MSNW. Furthermore, it also appears possible to operate a simplified form of this reactor using a pure D-D fuel cycle after an initial D-T ignition ramp to reach the advanced fuel operating regime. One optimistic reactor so designed has a length of about 35 meters, producing a net electrical power of about 375 MWe

  6. Reverse flow and vortex breakdown in a shear-thinning fluid

    International Nuclear Information System (INIS)

    Cabeza, C; Sarasua, G; Barrere, N; Marti, A C

    2011-01-01

    The effect of polymer concentration on the development of reverse secondary flow and vortex breakdown was studied using a viscoelastic solution of polyacrlylamide in water. The fluid was contained in cylindrical containers of two different radii, the top end wall of which rotated at a varying speed, thus, imparting a circulating motion to the fluid. Whereas using a newtonian fluid, streamlines will occupy the entire container, the flow of a shear-thinning fluid may divide into two cells of opposite circulating motion. The curve of critical Reynolds and elasticity numbers (Re, E) values corresponding to the development of reverse flow was obtained over a wide range of Re values. Vortex breakdown was found to occur at extremely low Re values.

  7. Deuterium-Tritium Simulations of the Enhanced Reversed Shear Mode in the Tokamak Fusion Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mikkelsen, D.R.; Manickam, J.; Scott, S.D.; Zarnstorff

    1997-04-01

    The potential performance, in deuterium-tritium plasmas, of a new enhanced con nement regime with reversed magnetic shear (ERS mode) is assessed. The equilibrium conditions for an ERS mode plasma are estimated by solving the plasma transport equations using the thermal and particle dif- fusivities measured in a short duration ERS mode discharge in the Tokamak Fusion Test Reactor [F. M. Levinton, et al., Phys. Rev. Letters, 75, 4417, (1995)]. The plasma performance depends strongly on Zeff and neutral beam penetration to the core. The steady state projections typically have a central electron density of {approx}2:5x10 20 m{sup -3} and nearly equal central electron and ion temperatures of {approx}10 keV. In time dependent simulations the peak fusion power, {approx} 25 MW, is twice the steady state level. Peak performance occurs during the density rise when the central ion temperature is close to the optimal value of {approx} 15 keV. The simulated pressure profiles can be stable to ideal MHD instabilities with toroidal mode number n = 1, 2, 3, 4 and {infinity} for {beta}{sub norm} up to 2.5; the simulations have {beta}{sub norm} {le} 2.1. The enhanced reversed shear mode may thus provide an opportunity to conduct alpha physics experiments in conditions imilar to those proposed for advanced tokamak reactors.

  8. Analytical reverse time migration: An innovation in imaging of infrastructures using ultrasonic shear waves.

    Science.gov (United States)

    Asadollahi, Aziz; Khazanovich, Lev

    2018-04-11

    The emergence of ultrasonic dry point contact (DPC) transducers that emit horizontal shear waves has enabled efficient collection of high-quality data in the context of a nondestructive evaluation of concrete structures. This offers an opportunity to improve the quality of evaluation by adapting advanced imaging techniques. Reverse time migration (RTM) is a simulation-based reconstruction technique that offers advantages over conventional methods, such as the synthetic aperture focusing technique. RTM is capable of imaging boundaries and interfaces with steep slopes and the bottom boundaries of inclusions and defects. However, this imaging technique requires a massive amount of memory and its computation cost is high. In this study, both bottlenecks of the RTM are resolved when shear transducers are used for data acquisition. An analytical approach was developed to obtain the source and receiver wavefields needed for imaging using reverse time migration. It is shown that the proposed analytical approach not only eliminates the high memory demand, but also drastically reduces the computation time from days to minutes. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Shear behavior of prestressed precast beams made of self-compacting fiber reinforced concrete

    OpenAIRE

    Cuenca Asensio, Estefanía; Serna Ros, Pedro

    2013-01-01

    Even after many years of in-depth research the shear behavior of concrete structures is still a subject for debate. Current Design Codes need to be adapted to new materials and production methods. This paper discusses some still unresolved doubts, based on an experimental program consisting of nine prestressed l-beams of different flange dimensions. Shear evaluation is analyzed in accordance with the Codes under different conditions: a combination of fibers with stirrups, the possible influen...

  10. Escape patterns due to ergodic magnetic limiters in tokamaks with reversed magnetic shear

    International Nuclear Information System (INIS)

    Roberto, M.; Da Silva, E.C.; Caldas, I.L.; Viana, R.L.

    2004-01-01

    In this work we study the ergodic magnetic limiters (EML) action on field lines from the point of view of a chaotic scattering process, considering the so-called exit basins, or sets of points in the chaotic region which originate field lines hitting the wall in some specified region. We divide the tokamak wall into three areas of equal poloidal angular length, corresponding to different exits for a chaotic field line. In order to obtain the exit basins we used a grid chosen inside a small rectangle which comprises a representative part of the chaotic region near the wall. Thus, exit basins were obtained for a tokamak wall with reversed magnetic shear. The no-twist mapping describes the perturbed magnetic field lines with two chains of magnetic islands and chaotic field lines in their vicinity. For a perturbing resonant magnetic field with a fixed helicity, the observed escape pattern changes with the perturbation intensity. (authors)

  11. The effect of toroidal plasma rotation on low-frequency reversed shear Alfvén eigenmodes in tokamaks

    NARCIS (Netherlands)

    J.W. Haverkort (Willem)

    2012-01-01

    htmlabstractThe influence of toroidal plasma rotation on the existence of reversed shear Alfvén eigenmodes (RSAEs) near their minimum frequency is investigated analytically. An existence condition is derived showing that a radially decreasing kinetic energy density is unfavourable for the existence

  12. Effect of percentage of low plastic fines on the unsaturated shear strength of compacted gravel soil

    Directory of Open Access Journals (Sweden)

    Kamal Mohamed Hafez Ismail Ibrahim

    2015-06-01

    Full Text Available Low plastic fines in gravel soils affect its unsaturated shear strength due to the contribution of matric suction that arises in micro and macro pores found within and between aggregates. The shear strength of five different types of prepared gravel soils is measured and is compared with a theoretical model (Fredlund et al., 1978 to predict the unsaturated shear strength. The results are consistent to a great extent except the case of dry clayey gravel soil. It is also found that on inundation of gravel soils containing plastic fines greater than 12% a considerable reduction in both the strength and the stiffness modulus is noticed. This 12% percentage is close to the accepted 15% percentage of fines given by ASTM D4318 (American society for testing material. The angle of internal friction that arises due to matric suction decreases with the increase of degree of saturation of soil. The hysteresis of some tested gravel soils is measured and found that it increases by increasing the percentage of fines.

  13. PZT-Based Detection of Compactness of Concrete in Concrete Filled Steel Tube Using Time Reversal Method

    Directory of Open Access Journals (Sweden)

    Shi Yan

    2014-01-01

    Full Text Available A smart aggregate-based approach is proposed for the concrete compactness detection of concrete filled steel tube (CFST columns. The piezoceramic-based smart aggregates (SAs were embedded in the predetermined locations prior to the casting of concrete columns to establish a wave-based smart sensing system for the concrete compactness detection purpose. To evaluate the efficiency of the developed approach, six specimens of the CFST columns with the rectangular cross-section were produced by placing some artificial defects during casting of concrete for simulating various uncompacted voids such as cavities, cracks, and debond. During the test, the time reversal technology was applied to rebuild the received signals and launch the reversed signals again by SAs, to overcome the issue of the lack of the prototype. Based on the proposed nonprototype, two indices of time reversibility (TR and symmetry (SYM were applied to relatively evaluate the level of concrete compactness in the range of the two SAs. The experimental results show that the developed method can effectively detect the compactness of concrete in CFST columns.

  14. Gyrokinetic global analysis of ion temperature gradient driven mode in reversed shear tokamaks

    International Nuclear Information System (INIS)

    Idomura, Y.; Tokuda, S.; Kishimoto, Y.

    2003-01-01

    A new toroidal gyrokinetic particle code has been developed to study the ion temperature gradient driven (ITG) turbulence in reactor relevant tokamak parameters. We use a new method based on a canonical Maxwellian distribution F CM (P φ , ε, μ), which is defined by three constants of motion in the axisymmetric toroidal system, the canonical angular momentum P φ , the energy ε, and the magnetic moment μ. A quasi-ballooning representation enables linear and nonlinear high-m,n global calculations with a good numerical convergence. Conservation properties are improved by using the optimized loading method. From comprehensive linear global analyses over a wide range of an unstable toroidal mode number spectrum (n=0∼100) in large tokamak parameters (a/ρ ti =320∼460), properties of the ITG modes in reversed shear tokamaks are discussed. In the nonlinear simulation, it is found that a new method based on F CM can simulate a zonal flow damping correctly, and spurious zonal flow oscillations, which are observed in a conventional method based on a local Maxwellian distribution F LM (ψ, ε, μ), do not appear in the nonlinear regime. (author)

  15. Sustainment of high confinement in JT-60U reversed shear plasmas

    International Nuclear Information System (INIS)

    Fujita, T.; Kamada, Y.; Ide, S.; Takeji, S.; Sakamoto, Y.; Isayama, A.; Suzuki, T.; Oikawa, T.; Fukuda, T.

    2001-01-01

    confinement is achieved owing to strong internal transport barriers (ITBs), are reported. In a high current plasma with an L-mode edge, deuterium-tritium-equivalent fusion power gain, Q DT eq =0.5 was sustained for 0.8 s (∼ energy confinement time) by adjusting plasma beta precisely using feedback control of stored energy. In a high triangularity plasma with an ELMy H-mode edge, the shrinkage of reversed shear region was suppressed and quasi steady sustainment of high confinement was achieved by raising the poloidal beta and enhancing the bootstrap current peaked at the ITB layer. High bootstrap current fraction (∼80%) was obtained in a high q regime (q 95 ∼9), which leaded to full non-inductive current drive condition. The normalized beta (β N ) of ∼ 2 and H-factor of H 89 ∼3.5 (HH 98y2 ∼2.2) were sustained for 2.7 s (∼ 6 times energy confinement time). (author)

  16. Phase contrast imaging measurements of reversed shear Alfvén eigenmodes during sawteeth in Alcator C-Moda)

    Science.gov (United States)

    Edlund, E. M.; Porkolab, M.; Kramer, G. J.; Lin, L.; Lin, Y.; Wukitch, S. J.

    2009-05-01

    Reversed shear Alfvén eigenmodes (RSAEs) have been observed with the phase contrast imaging diagnostic and Mirnov coils during the sawtooth cycle in Alcator C-mod [M. Greenwald et al., Nucl. Fusion 45, S109 (2005)] plasmas with minority ion-cyclotron resonance heating. Both down-chirping RSAEs and up-chirping RSAEs have been observed during the sawtooth cycle. Experimental measurements of the spatial structure of the RSAEs are compared to theoretical models based on the code NOVA [C. Z. Cheng and M. S. Chance, J. Comput. Phys. 71, 124 (1987)] and used to derive constraints on the q profile. It is shown that the observed RSAEs can be understood by assuming a reversed shear q profile (up chirping) or a q profile with a local maximum (down chirping) with q ≈1.

  17. Compact toroid injection fueling in a large field-reversed configuration

    Science.gov (United States)

    Asai, T.; Matsumoto, T.; Roche, T.; Allfrey, I.; Gota, H.; Sekiguchi, J.; Edo, T.; Garate, E.; Takahashi, Ts.; Binderbauer, M.; Tajima, T.

    2017-07-01

    A repetitively driven compact toroid (CT) injector has been developed for the large field-reversed configuration (FRC) facility of the C-2/C-2U, primarily for particle refueling. A CT is formed and injected by a magnetized coaxial plasma gun (MCPG) exclusively developed for the C-2/C-2U FRC. To refuel the particles of long-lived FRCs, multiple CT injections are required. Thus, a multi-stage discharge circuit was developed for a multi-pulsed CT injection. The drive frequency of this system can be adjusted up to 1 kHz and the number of CT shots per injector is two; the system can be further upgraded for a larger number of injection pulses. The developed MCPG can achieve a supersonic ejection velocity in the range of ~100 km s-1. The key plasma parameters of electron density, electron temperature and the number of particles are ~5  ×  1021 m-3, ~30 eV and 0.5-1.0  ×  1019, respectively. In this project, single- and double-pulsed counter CT injection fueling were conducted on the C-2/C-2U facility by two CT injectors. The CT injectors were mounted 1 m apart in the vicinity of the mid-plane. To avoid disruptive perturbation on the FRC, the CT injectors were operated at the lower limit of the particle inventory. The experiments demonstrated successful refueling with a significant density build-up of 20-30% of the FRC particle inventory per single CT injection without any deleterious effects on the C-2/C-2U FRC.

  18. Overview of the ARIES-RS reversed-shear tokamak power plant study

    International Nuclear Information System (INIS)

    Najmabadi, F.; Billone, M.C.

    1997-01-01

    The ARIES-RS tokamak is a conceptual, D-T-burning 1000 MWe power plant. As with earlier ARIES design studies, the final design of ARIES-RS was obtained in a self-consistent manner using the best available physics and engineering models. Detailed analyses of individual systems together with system interfaces and interactions were incorporated into the ARIES systems code in order to assure self-consistency and to optimize towards the lowest cost system. The ARIES-RS design operates with a reversed-shear plasma and employs a moderate aspect ratio (A=4.0). The plasma current is relatively low (I p =11.32 MA) and bootstrap current fraction is high (f BC =0.88). Consequently, the auxiliary power required for RF current drive is relatively low (∝80 MW). At the same time, the average toroidal beta is high (β=5%), providing power densities near practical engineering limits (the peak neutron wall loading is 5.7 MW m -2 ). The toroidal-field (TF) coil system is designed with relatively 'conventional' materials (Nb 3 Sn and NbTi conductor with 316SS structures), and is operated at a design limit of ∝16 T at the coil in order to optimize the design point. The ARIES-RS design uses a self-cooled lithium blanket with vanadium alloy as the structural material. The V-alloy has low activation, low afterheat, high temperature capability and can handle high heat flux. A self-cooled liquid lithium blanket is simple, and with the development of an insulating coating, has low operating pressure. Also, this blanket gives excellent neutronics performance. Detailed analysis has been performed to minimize the cost and maximize the performance of the blanket and shield. (orig.)

  19. Shear Reversal and Mhd Activity During Pellet Enhanced Performance Pulses in Jet

    NARCIS (Netherlands)

    Hugon, M.; van Milligen, B. P.; Smeulders, P.; Appel, L. C.; Bartlett, D. V.; Boucher, D.; Edwards, A. W.; Eriksson, L. G.; Gowers, C. W.; Hender, T. C.; Huysmans, G.; Jacquinot, J. J.; Kupschus, P.; Porte, L.; Rebut, P. H.; Start, D. F. H.; Tibone, F.; Tubbing, B. J. D.; Watkins, M. L.; Zwingmann, W.

    1992-01-01

    Analysis of MHD activity in Pellet Enhanced Performance (PEP) pulses is used to determine the position of rational surfaces associated with the safety factor q. This gives evidence for negative shear in the central region of the plasma. The plasma equilibrium calculated from the measured q values

  20. Dynamic behavior of transport in normal and reversed shear plasmas with internal barriers in JT-60U

    International Nuclear Information System (INIS)

    Neudatchin, Sergi V.; Takizuka, Tomonori; Shirai, Hiroshi; Fujita, Takaaki; Isayama, Akihiko; Kamada, Yutaka; Koide, Yoshihiko

    2001-12-01

    Transport evolution in normal shear (NrS) and reversed shear (RS) JT-60U tokamak plasmas with internal transport barrier (ITB) is described as a combination of various fast and slow time scale processes. Abrupt in time (ms time scale) and wide in space (∼0.3 of minor radius) variations of electron and ion heat diffusivities χ e,i (δχ e,i ), which are called ITB-events and seen as simultaneous rise and decay of electron and ion temperatures in two spatial zones, are found for weak ITBs in both NrS and RS plasmas. Profiles of δχ e in RS plasmas with strong ITBs are usually localized near ITB foot inside smaller space region. The maximum of the heat flux variation is located near position of the minimum of safety factor in various RS plasmas, and variation is extended in positive shear region. Inward and outward heat pulse propagations created by the jump of χ e and the sawtooth-like crash are analyzed. Small values of χ e and the absence of heat pinch are found inside strong ITBs. Another non-local abrupt variations of χ e inside most of the plasma volume, including significant part of weak ITB inside RS zone of RS plasmas, are seen at the ELM-induced H-L transition and the L-H recovery. (author)

  1. Indirect, reversible high-density hydrogen storage in compact metal ammine salts

    DEFF Research Database (Denmark)

    Sørensen, Rasmus Zink; Hummelshøj, Jens Strabo; Klerke, Asbjørn

    2008-01-01

    structures develop, which facilitates desorption from the interior of large, compact tablets. Density functional theory calculations reproduce trends in desorption enthalpies for the systems studied, and a mechanism in which individual chains of the ammines are released from the surface of the crystal......The indirect hydrogen storage capabilities of Mg(NH3)(6)Cl-2, Ca(NH3)(6)Cl-2, Mn(NH3)(6)Cl-2, and Ni(NH3)(6)Cl-2 are investigated. All four metal ammine chlorides can be compacted to solid tablets with densities of at least 95% of the crystal density. This gives very high indirect hydrogen...... densities both gravimetrically and volumetrically. Upon heating, NH3 is released from the salts, and by employing an appropriate catalyst, H-2 can be released corresponding to up to 9.78 wt % H and 0.116 kg H/L for the Ca(NH3)(8)Cl-2 salt. The NH3 release from all four salts is investigated using...

  2. Experimental Study of Reversed Shear Alfven Eigenmodes During The Current Ramp In The Alcator C-Mod Tokamak

    International Nuclear Information System (INIS)

    Edlund, E.M.; Porkolab, M.; Kramer, G.J.; Lin, L.; Lin, Y.; Tsuji, N.; Wukitch, S.J.

    2010-01-01

    Experiments conducted in the Alcator C-Mod tokamak at MIT have explored the physics of reversed shear Alfven eigenmodes (RSAEs) during the current ramp. The frequency evolution of the RSAEs throughout the current ramp provides a constraint on the evolution of q min , a result which is important in transport modeling and for comparison with other diagnostics which directly measure the magnetic field line structure. Additionally, a scaling of the RSAE minimum frequency with the sound speed is used to derive a measure of the adiabatic index, a measure of the plasma compressibility. This scaling bounds the adiabatic index at 1.40 ± 0.15 used in MHD models and supports the kinetic calculation of separate electron and ion compressibilities with an ion adiabatic index close to 7/4.

  3. Point design for deuterium-deuterium compact reversed-field pinch reactors

    International Nuclear Information System (INIS)

    Dabiri, A.E.; Dobrott, D.R.; Gurol, H.; Schnack, D.D.

    1984-01-01

    A deuterium-deuterium (D-D) reversed-field pinch (RFP) reactor may be made comparable in size and cost to a deuterium-tritium (D-T) reactor at the expense of high-thermal heat load to the first wall. This heat load is the result of the larger percentage of fusion power in charged particles in the D-D reaction as compared to the D-T reaction. The heat load may be reduced by increasing the reactor size and hence the cost. In addition to this ''degraded'' design, the size may be kept small by means of a higher heat load wall, or by means of a toroidal divertor, in which case most of the heat load seen by the wall is in the form of radiation. Point designs are developed for these approaches and cost studies are performed and compared with a D-T reactor. The results indicate that the cost of electricity of a D-D RFP reactor is about20% higher than a D-T RFP reactor. This increased cost could be offset by the inherent safety features of the D-D fuel cycle

  4. Development of a magnetized coaxial plasma gun for compact toroid injection into the C-2 field-reversed configuration device.

    Science.gov (United States)

    Matsumoto, T; Sekiguchi, J; Asai, T; Gota, H; Garate, E; Allfrey, I; Valentine, T; Morehouse, M; Roche, T; Kinley, J; Aefsky, S; Cordero, M; Waggoner, W; Binderbauer, M; Tajima, T

    2016-05-01

    A compact toroid (CT) injector was developed for the C-2 device, primarily for refueling of field-reversed configurations. The CTs are formed by a magnetized coaxial plasma gun (MCPG), which consists of coaxial cylindrical electrodes and a bias coil for creating a magnetic field. First, a plasma ring is generated by a discharge between the electrodes and is accelerated by Lorenz self-force. Then, the plasma ring is captured by an interlinkage flux (poloidal flux). Finally, the fully formed CT is ejected from the MCPG. The MCPG described herein has two gas injection ports that are arranged tangentially on the outer electrode. A tungsten-coated inner electrode has a head which can be replaced with a longer one to extend the length of the acceleration region for the CT. The developed MCPG has achieved supersonic CT velocities of ∼100 km/s. Plasma parameters for electron density, electron temperature, and the number of particles are ∼5 × 10(21) m(-3), ∼40 eV, and 0.5-1.0 × 10(19), respectively.

  5. Development of a magnetized coaxial plasma gun for compact toroid injection into the C-2 field-reversed configuration device

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, T., E-mail: cstd14003@g.nihon-u.ac.jp; Sekiguchi, J.; Asai, T. [College of Science and Technology, Nihon University, 1-8-14 Kanda, Chiyoda-ku, Tokyo 1018308 (Japan); Gota, H.; Garate, E.; Allfrey, I.; Valentine, T.; Morehouse, M.; Roche, T.; Kinley, J.; Aefsky, S.; Cordero, M.; Waggoner, W.; Binderbauer, M. [Tri Alpha Energy, Inc., P.O. Box 7010 Rancho Santa Margarita, California 92688 (United States); Tajima, T. [Tri Alpha Energy, Inc., P.O. Box 7010 Rancho Santa Margarita, California 92688 (United States); Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States)

    2016-05-15

    A compact toroid (CT) injector was developed for the C-2 device, primarily for refueling of field-reversed configurations. The CTs are formed by a magnetized coaxial plasma gun (MCPG), which consists of coaxial cylindrical electrodes and a bias coil for creating a magnetic field. First, a plasma ring is generated by a discharge between the electrodes and is accelerated by Lorenz self-force. Then, the plasma ring is captured by an interlinkage flux (poloidal flux). Finally, the fully formed CT is ejected from the MCPG. The MCPG described herein has two gas injection ports that are arranged tangentially on the outer electrode. A tungsten-coated inner electrode has a head which can be replaced with a longer one to extend the length of the acceleration region for the CT. The developed MCPG has achieved supersonic CT velocities of ∼100 km/s. Plasma parameters for electron density, electron temperature, and the number of particles are ∼5 × 10{sup 21} m{sup −3}, ∼40 eV, and 0.5–1.0 × 10{sup 19}, respectively.

  6. Physics-Based Compact Model for CIGS and CdTe Solar Cells: From Voltage-Dependent Carrier Collection to Light-Enhanced Reverse Breakdown: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xingshu; Alam, Muhammad Ashraful; Raguse, John; Garris, Rebekah; Deline, Chris; Silverman, Timothy

    2015-10-15

    In this paper, we develop a physics-based compact model for copper indium gallium diselenide (CIGS) and cadmium telluride (CdTe) heterojunction solar cells that attributes the failure of superposition to voltage-dependent carrier collection in the absorber layer, and interprets light-enhanced reverse breakdown as a consequence of tunneling-assisted Poole-Frenkel conduction. The temperature dependence of the model is validated against both simulation and experimental data for the entire range of bias conditions. The model can be used to characterize device parameters, optimize new designs, and most importantly, predict performance and reliability of solar panels including the effects of self-heating and reverse breakdown due to partial-shading degradation.

  7. Onshore-offshore evidence for periodic post-rift shear reversal along the Pernambuco Fracture Zone, NE Brazil

    Science.gov (United States)

    Balsamo, Fabrizio; Nestola, Yago; Storti, Fabrizio; Nogueira, Cézar; Bezerra, Hilario F. R.

    2014-05-01

    Oceanic facture zones are among the most evident bathymetric features of seafloors. They include transform faults that connect adjacent mid-ocean ridge segments and accommodate opposite spreading directions. According to the plate tectonics theory, only the latter are tectonically active. Recent onshore and offshore evidence in the Antarctic plate sector facing Australia suggest, conversely, that oceanic fracture zones can transfer shear into the plate interior. In this contribution we illustrate the results of a research project performed in the NE Brazilian passive margin, where the seismic activity is clustered along major crustal-scale, long-lived shear zones, thus resembling the Antarctic case. In particular, we performed a detailed study of the offshore pattern of seafloor age domains on both sides of the Pernambuco Fracture Zone (PFZ), which indicates non-uniform spreading rates on the two lithospheric lanes separated by the PFZ. The differential spreading rate, calculated in 8 age provinces from Upper Cretaceous to Present, varies between 1.3 and 8.8 mm/yr and periodically switched from right-lateral to left-lateral excess transform shear along the PFZ. Five major inversions were found, including a Tortonian inversion from right-lateral to left-lateral excess shear, consistently with structural data acquired in Miocene to Quaternary sediments along the PFZ. We discuss the impact of our findings in the current plate tectonic theory framework.

  8. The reversed-field pinch as a poloidal-field-dominated, compact, high-power-density fusion system

    International Nuclear Information System (INIS)

    Krakowski, R.A.

    1988-01-01

    This paper discusses the feasibility of reversed-field pinch devices as future thermonuclear reactors. Safety, cost, ion temperatures, Lawson numbers, and power densities are reviewed for these types of devices. 12 refs., 2 figs., 1 tab

  9. Specific features of the occurrence, development, and re-compaction of spall and shear fractures in spherically-convergent shells made of unalloyed iron and some steels under their spherical explosive loading

    International Nuclear Information System (INIS)

    Kozlov, E.A.; Brichikov, S.A.; Gorbachev, D.M.; Brodova, I.G.; Yablonskikh, T.I.

    2007-01-01

    Results of comparative metallographic examination of recovered shells exposed to explosive loading in two modes (with and without a heavy casing confining explosion products scatter) are presented. The shells were made of high-purity and technical-grade unalloyed iron with the initial grain size 250 and 125 μm, steel 30KhGSA in delivery state and quenched up to HR C 35...40, austenitic stainless steel 12Kh18N10T. The heavy casing used in experiments is demonstrated to ensure a rather compact convergence of shells destroyed at high radii. In the described comparative experiments, one managed to compile the 12Kh18N10T steel shell, after it was spalled at high radii and exposed to shear fracture and spallation layer fragmentation at medium radii, into a compact sphere but failed to do the same with the 30KhGSA quenched steel shell after it was fractured according to spall and shear mechanisms at high and medium radii. Polar zones of this steel shell have obvious undercompressed areas due to significant dissipative losses to overcome the shear strength. Occurrence, development, and re-compaction of spall and shear fractures in spherically-convergent shells made of materials, which were already carefully investigated in 1D- and 2D-geometry experiments, were systematically studied in order to verify and validate new physical models of dynamic fractures, as well as up-to-date used in 1D-, 2D- and 3D-numerical algorithms [ru

  10. Multi Resonance Shear Mode Transducers

    Science.gov (United States)

    2016-11-21

    engineering in the single crystal lead magnesium niobate-lead titanate (PMNT) system has uncovered a very unique piezoelectric shear mode. Contrary to...ABSTRACT Crystallographic engineering of single crystal relaxor-based ferroelectrics was used to design broadband, compact, high power, low frequency...utilize the d36 shear piezoelectric coefficient, which has advantages for compact low frequency sonar transducers. The d36 cut is unique in that large

  11. US-Japan workshop on field-reversed configurations with steady-state high-temperature fusion plasmas and the 11th US-Japan workshop on compact toroids

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, D.C.; Fernandez, J.C.; Rej, D.J. (comps.)

    1990-05-01

    The US-Japan Workshop on Field-Reversed Configurations with Steady-State High-Temperature Fusion Plasma and the 11th US-Japan Workshop on Compact Toroids were held at Los Alamos National Laboratory, Los Alamos, New Mexico on November 7--9, 1989. These proceedings contain the papers presented at the workshops as submitted by the authors. These papers have been indexed separately.

  12. Physics of Compact Advanced Stellarators

    International Nuclear Information System (INIS)

    Zarnstorff, M.C.; Berry, L.A.; Brooks, A.; Fredrickson, E.; Fu, G.-Y.; Hirshman, S.; Hudson, S.; Ku, L.-P.; Lazarus, E.; Mikkelsen, D.; Monticello, D.; Neilson, G.H.; Pomphrey, N.; Reiman, A.; Spong, D.; Strickler, D.; Boozer, A.; Cooper, W.A.; Goldston, R.; Hatcher, R.; Isaev, M.; Kessel, C.; Lewandowski, J.; Lyon, J.; Merkel, P.; Mynick, H.; Nelson, B.E.; Nuehrenberg, C.; Redi, M.; Reiersen, W.; Rutherford, P.; Sanchez, R.; Schmidt, J.; White, R.B.

    2001-01-01

    Compact optimized stellarators offer novel solutions for confining high-beta plasmas and developing magnetic confinement fusion. The 3-D plasma shape can be designed to enhance the MHD stability without feedback or nearby conducting structures and provide drift-orbit confinement similar to tokamaks. These configurations offer the possibility of combining the steady-state low-recirculating power, external control, and disruption resilience of previous stellarators with the low-aspect ratio, high beta-limit, and good confinement of advanced tokamaks. Quasi-axisymmetric equilibria have been developed for the proposed National Compact Stellarator Experiment (NCSX) with average aspect ratio 4-4.4 and average elongation of approximately 1.8. Even with bootstrap-current consistent profiles, they are passively stable to the ballooning, kink, vertical, Mercier, and neoclassical-tearing modes for beta > 4%, without the need for external feedback or conducting walls. The bootstrap current generates only 1/4 of the magnetic rotational transform at beta = 4% (the rest is from the coils), thus the equilibrium is much less nonlinear and is more controllable than similar advanced tokamaks. The enhanced stability is a result of ''reversed'' global shear, the spatial distribution of local shear, and the large fraction of externally generated transform. Transport simulations show adequate fast-ion confinement and thermal neoclassical transport similar to equivalent tokamaks. Modular coils have been designed which reproduce the physics properties, provide good flux surfaces, and allow flexible variation of the plasma shape to control the predicted MHD stability and transport properties

  13. Shear machines

    International Nuclear Information System (INIS)

    Astill, M.; Sunderland, A.; Waine, M.G.

    1980-01-01

    A shear machine for irradiated nuclear fuel elements has a replaceable shear assembly comprising a fuel element support block, a shear blade support and a clamp assembly which hold the fuel element to be sheared in contact with the support block. A first clamp member contacts the fuel element remote from the shear blade and a second clamp member contacts the fuel element adjacent the shear blade and is advanced towards the support block during shearing to compensate for any compression of the fuel element caused by the shear blade (U.K.)

  14. Advances in compact torus research

    International Nuclear Information System (INIS)

    1986-05-01

    A compact torus is a low aspect ratio, axisymmetric, closed magnetic field line configuration with no vessel wall or magnetic field coils linking the hole in the plasma toroid. This concept offers reactor advantages such as simplicity, high β, and the possibility of translation. Several methods have been used to generate compact toroids, including plasma guns, high energy particle rings, and field-reversed theta pinches. This document summarizes the results of recent work on compact toroids, presented at the first IAEA Technical Committee Meeting on Compact Torus Research held in Sydney, Australia from 4 to 7 March 1985

  15. Acoustic and Shear-Wave Velocities in Hydrate-Bearing Sediments Offshore Southwestern Taiwan: Tomography, Converted Waves Analysis and Reverse-Time Migration of OBS Records

    Directory of Open Access Journals (Sweden)

    Philippe Schnurle

    2006-01-01

    Full Text Available A 2.5-D combined seismic reflection and refraction survey has been conducted in the accretionary complex offshore of southwestern Taiwan where BSRs (Bottom Simulating Reflectors are highly concentrated and geochemical signals for the presence of gas hydrate are strong. In this study, we perform velocity analysis of the 6 4-component OBS (Ocean-Bottom Seismometer records along the southernmost transect of this seismic experiment. We utilize 3 independent methods in order to accurately determine the acoustic and shear-wave velocities of the sediments: 1-D Root Mean Square (RMS analysis of the P-P and P-S reflected events on individual datumed components, 2-D inversion of the P-P and P-S reflected and refracted events along the in-line transect, and 3-D acoustic inversion of the first arrivals. The principal sources of bias in the determination of the velocities are the 3-dimentional nature of the topography and the complexity of the underlying structures. The three methods result in consistent velocity profiles. Rapid lateral and vertical variations of the velocities are observed. We then investigate the large scale gas hydrate content through rock physic modeling: at the vertical of each OBS, shear-waves velocities are utilized to estimate the water-filled porosities, and the acoustic velocities predicted for a set of gas hydrate, quartz and clay contents are compared to the observed profiles.

  16. FAMECE Compaction Study - Phase I

    Science.gov (United States)

    1980-08-01

    apparatus chosen for the compaction study is model CN-992, manufactured by Soiltest. In(c., of’ Evanston, Illinois. This model is part of the Army Soill...Figure 17) is model CL-700, nmanufactured by Soiltest, Inc.. of Evanston, Illinois. It has a foot adapter (CL-701) for low-shear-strength soils. It will be...moderate plasticity. 12. Soil Characteristics. Samples of’ thc three soil types were analyzed -with stand- ardl soils testinig eq(uipmlent. Sieve, or

  17. Simulations of Granular Particles Under Cyclic Shear

    Science.gov (United States)

    Royer, John; Chaikin, Paul

    2012-02-01

    We perform molecular dynamics (MD) simulations of spherical grains subjected to cyclic, quasi-static shear in a 3D parallelepiped shear cell. This virtual shear cell is constructed out of rough, bumpy walls in order to minimize wall-induced ordering and has an open top surface to allow the packing to readily dilate or compact. Using a standard routine for MD simulations of frictional grains, we simulate over 1000 shear cycles, measuring grain displacements, the local packing density and changes in the contact network. Varying the shear amplitude and the friction coefficient between grains, we map out a phase diagram for the different types of behavior exhibited by these sheared grains. With low friction and high enough shear, the grains can spontaneously order into densely packed crystals. With low shear and increasing friction the packing remains disordered, yet the grains arrange themselves into configurations which exhibit limit cycles where all grains return to the same position after each full shear cycle. At higher shear and friction there is a transition to a diffusive state, where grains continue rearrange and move throughout the shear cell.

  18. Compact vortices

    Energy Technology Data Exchange (ETDEWEB)

    Bazeia, D.; Losano, L.; Marques, M.A.; Zafalan, I. [Universidade Federal da Paraiba, Departamento de Fisica, Joao Pessoa, PB (Brazil); Menezes, R. [Universidade Federal da Paraiba, Departamento de Ciencias Exatas, Rio Tinto, PB (Brazil); Universidade Federal de Campina Grande, Departamento de Fisica, Campina Grande, PB (Brazil)

    2017-02-15

    We study a family of Maxwell-Higgs models, described by the inclusion of a function of the scalar field that represent generalized magnetic permeability. We search for vortex configurations which obey first-order differential equations that solve the equations of motion. We first deal with the asymptotic behavior of the field configurations, and then implement a numerical study of the solutions, the energy density and the magnetic field. We work with the generalized permeability having distinct profiles, giving rise to new models, and we investigate how the vortices behave, compared with the solutions of the corresponding standard models. In particular, we show how to build compact vortices, that is, vortex solutions with the energy density and magnetic field vanishing outside a compact region of the plane. (orig.)

  19. Compact magnetic confinement fusion: Spherical torus and compact torus

    Directory of Open Access Journals (Sweden)

    Zhe Gao

    2016-05-01

    Full Text Available The spherical torus (ST and compact torus (CT are two kinds of alternative magnetic confinement fusion concepts with compact geometry. The ST is actually a sub-category of tokamak with a low aspect ratio; while the CT is a toroidal magnetic configuration with a simply-connected geometry including spheromak and field reversed pinch. The ST and CT have potential advantages for ultimate fusion reactor; while at present they can also provide unique fusion science and technology contributions for mainstream fusion research. However, some critical scientific and technology issues should be extensively investigated.

  20. Designing shear-thinning

    Science.gov (United States)

    Nelson, Arif Z.; Ewoldt, Randy H.

    2017-11-01

    Design in fluid mechanics often focuses on optimizing geometry (airfoils, surface textures, microfluid channels), but here we focus on designing fluids themselves. The dramatically shear-thinning ``yield-stress fluid'' is currently the most utilized non-Newtonian fluid phenomenon. These rheologically complex materials, which undergo a reversible transition from solid-like to liquid-like fluid flow, are utilized in pedestrian products such as paint and toothpaste, but also in emerging applications like direct-write 3D printing. We present a paradigm for yield-stress fluid design that considers constitutive model representation, material property databases, available predictive scaling laws, and the many ways to achieve a yield stress fluid, flipping the typical structure-to-rheology analysis to become the inverse: rheology-to-structure with multiple possible materials as solutions. We describe case studies of 3D printing inks and other flow scenarios where designed shear-thinning enables performance remarkably beyond that of Newtonian fluids. This work was supported by Wm. Wrigley Jr. Company and the National Science Foundation under Grant No. CMMI-1463203.

  1. Pharmaceutical powder compaction technology

    National Research Council Canada - National Science Library

    Çelik, Metin

    2011-01-01

    ... through the compaction formulation process and application. Compaction of powder constituents both active ingredient and excipients is examined to ensure consistent and reproducible disintegration and dispersion profiles...

  2. Constant load and constant volume response of municipal solid waste in simple shear.

    Science.gov (United States)

    Zekkos, Dimitrios; Fei, Xunchang

    2017-05-01

    Constant load and constant volume simple shear testing was conducted on relatively fresh municipal solid waste (MSW) from two landfills in the United States, one in Michigan and a second in Texas, at respective natural moisture content below field capacity. The results were assessed in terms of two failure strain criteria, at 10% and 30% shear strain, and two interpretations of effective friction angle. Overall, friction angle obtained assuming that the failure plane is horizontal and at 10% shear strain resulted in a conservative estimation of shear strength of MSW. Comparisons between constant volume and constant load simple shear testing results indicated significant differences in the shear response of MSW with the shear resistance in constant volume being lower than the shear resistance in constant load. The majority of specimens were nearly uncompacted during specimen preparation to reproduce the state of MSW in bioreactor landfills or in uncontrolled waste dumps. The specimens had identical percentage of waste. The results of these tests suggest the possibility of significantly lower shear strength of MSW in bioreactor landfills where waste is placed with low compaction effort and constant volume, i.e., "undrained", conditions may occur. Compacted MSW specimens resulted in shear strength parameters that are higher than uncompacted specimens and closer to values reported in the literature. However, the normalized undrained shear strength in simple shear for uncompacted and compacted MSW was still higher than the normalized undrained shear strength reported in the literature for clayey and silty soils. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Shear zones between rock units with no relative movement

    DEFF Research Database (Denmark)

    Koyi, H.; Schmeling, H.; Burchardt, S.

    2012-01-01

    Shear zones are normally viewed as relatively narrow deformation zones that accommodate relative displacement between two "blocks" that have moved past each other in opposite directions. This study reports localized zones of shear between adjacent blocks that have not moved past each other...... magma body (stoping). From the fluid dynamics point of view these shear zones can be regarded as the low Reynolds number deformation zones within the wake of a body moving through a viscous medium. While compact (aspect ratio 1:1:1) moving bodies generate axial symmetric (cone like) shear zones...

  4. Shear zones between rock units with no relative movement

    DEFF Research Database (Denmark)

    Koyi, Hemin; Schmeling, Harro; Burchardt, Steffi

    2013-01-01

    Shear zones are normally viewed as relatively narrow deformation zones that accommodate relative displacement between two "blocks" that have moved past each other in opposite directions. This study reports localized zones of shear between adjacent blocks that have not moved past each other...... a partially molten magma body (stoping). From the fluid dynamics perspective these shear zones can be regarded as low Reynolds number deformation zones within the wake of a body moving through a viscous medium. While compact moving bodies (aspect ratio 1:1:1) generate axial symmetric (cone like) shear zones...

  5. Model Compaction Equation

    African Journals Online (AJOL)

    Petrophysical, Decompaction and Linear Regression techniques were used to investigate overpressure, degree of compaction and to derive a model compaction equation for. -1. -1 hydrostatic sandstones. Compaction coefficients obtained range from 0.0003 - 0.0005 m (averaging 0.0004 m ) and percentage compaction ...

  6. Assessment of soil compaction properties based on surface wave techniques

    Science.gov (United States)

    Jihan Syamimi Jafri, Nur; Rahim, Mohd Asri Ab; Zahid, Mohd Zulham Affandi Mohd; Faizah Bawadi, Nor; Munsif Ahmad, Muhammad; Faizal Mansor, Ahmad; Omar, Wan Mohd Sabki Wan

    2018-03-01

    Soil compaction plays an important role in every construction activities to reduce risks of any damage. Traditionally, methods of assessing compaction include field tests and invasive penetration tests for compacted areas have great limitations, which caused time-consuming in evaluating large areas. Thus, this study proposed the possibility of using non-invasive surface wave method like Multi-channel Analysis of Surface Wave (MASW) as a useful tool for assessing soil compaction. The aim of this study was to determine the shear wave velocity profiles and field density of compacted soils under varying compaction efforts by using MASW method. Pre and post compaction of MASW survey were conducted at Pauh Campus, UniMAP after applying rolling compaction with variation of passes (2, 6 and 10). Each seismic data was recorded by GEODE seismograph. Sand replacement test was conducted for each survey line to obtain the field density data. All seismic data were processed using SeisImager/SW software. The results show the shear wave velocity profiles increase with the number of passes from 0 to 6 passes, but decrease after 10 passes. This method could attract the interest of geotechnical community, as it can be an alternative tool to the standard test for assessing of soil compaction in the field operation.

  7. Inplane shear capacity of reinforced composite masonry block walls

    International Nuclear Information System (INIS)

    White, W.H.; Tseng, W.S.

    1981-01-01

    The objective of this paper is to describe a test program performed to determine the inplane shear capacity, stiffness and ductility of composite masonry walls subjected to earthquake type loadings. Specimens were simultaneously subjected to a range of compressive loads to simulate dead load; and inplane shear loads with full load reversal to simulate the earthquake cycling load. The influence of horizontal and vertical reinforcing steel percentages on the inplane shear capacity, stiffness and ductility was also investigated. (orig./HP)

  8. Compaction and flow rule of oxide nanopowders

    Science.gov (United States)

    Boltachev, G. Sh.; Lukyashin, K. E.; Maximenko, A. L.; Maksimov, R. N.; Shitov, V. A.; Shtern, M. B.

    2017-09-01

    Transparent Al2O3 ceramics have attracted considerable interest for use in a wide range of optical, electronic and structural applications. The fabrication of these ceramics using powder metallurgy processes requires the development of theoretical approaches to the compaction of nanopowders. In this work, we investigate the compaction processes of two model granular systems imitating Al2O3 nanosized powders. System I is a loosely aggregated powder, and system II is a powder strongly inclined to agglomeration (for instance, calcined powder). The processes of isostatical (uniform), biaxial, and uniaxial compaction as well as uniaxial compaction with simultaneous shear deformation are studied. The energy parameters of compaction such as the energy change of elastic interparticle interactions and dispersion interactions, dissipative energy losses related to the processes of interparticle friction, and the total work of compaction are calculated for all the processes. The nonapplicability of the associated flow rule to the description of deformation processes of oxide nanopowders is shown and an alternative plastic flow rule is suggested. A complete system of determining the relationship of the flow including analytical approximations of yield surfaces is obtained.

  9. Fuzzy Inverse Compactness

    Directory of Open Access Journals (Sweden)

    Halis Aygün

    2008-01-01

    Full Text Available We introduce definitions of fuzzy inverse compactness, fuzzy inverse countable compactness, and fuzzy inverse Lindelöfness on arbitrary -fuzzy sets in -fuzzy topological spaces. We prove that the proposed definitions are good extensions of the corresponding concepts in ordinary topology and obtain different characterizations of fuzzy inverse compactness.

  10. The relation between granule size, granule stickiness, and torque in the high-shear granulation process

    NARCIS (Netherlands)

    Bouwman, A.M.; Henstra, M.J.; Hegge, J.J.M.E.; Zhang, Z.; Ingram, A.; Seville, J.P.K.; Frijlink, H.W.

    2005-01-01

    Purpose. To investigate the background of the observed relationship between measured torque and granule size in high-shear granulation processes. Methods. Torque was measured during the granulation process; the behavior of individual wet granules during compaction was investigated using

  11. Magnetohydodynamics stability of compact stellarators

    International Nuclear Information System (INIS)

    Fu, G.Y.; Ku, L.P.; Cooper, W.A.; Hirshman, S.H.

    2000-01-01

    Recent stability results of external kink modes and vertical modes in compact stellarators are presented. The vertical mode is found to be stabilized by externally generated poloidal flux. A simple stability criterion is derived in the limit of large aspect ratio and constant current density. For a wall at infinite distance from the plasma, the amount of external flux needed for stabilization is given by Fi = (k2 minus k)=(k2 + 1), where k is the axisymmetric elongation and Fi is the fraction of the external rotational transform. A systematic parameter study shows that the external kink mode in QAS can be stabilized at high beta (approximately 5%) without a conducting wall by magnetic shear via 3D shaping. It is found that external kinks are driven by both parallel current and pressure gradient. The pressure contributes significantly to the overall drive through the curvature term and the Pfirsch-Schluter current

  12. Effects of shear coupling on shear properties of wood

    Science.gov (United States)

    Jen Y. Liu

    2000-01-01

    Under pure shear loading, an off-axis element of orthotropic material such as pure wood undergoes both shear and normal deformations. The ratio of the shear strain to a normal strain is defined as the shear coupling coefficient associated with the direction of the normal strain. The effects of shear coupling on shear properties of wood as predicted by the orthotropic...

  13. DNA compaction by azobenzene-containing surfactant

    International Nuclear Information System (INIS)

    Zakrevskyy, Yuriy; Kopyshev, Alexey; Lomadze, Nino; Santer, Svetlana; Morozova, Elena; Lysyakova, Ludmila; Kasyanenko, Nina

    2011-01-01

    We report on the interaction of cationic azobenzene-containing surfactant with DNA investigated by absorption and fluorescence spectroscopy, dynamic light scattering, and atomic force microscopy. The properties of the surfactant can be controlled with light by reversible switching of the azobenzene unit, incorporated into the surfactant tail, between a hydrophobic trans (visible irradiation) and a hydrophilic cis (UV irradiation) configuration. The influence of the trans-cis isomerization of the azobenzene on the compaction process of DNA molecules and the role of both isomers in the formation and colloidal stability of DNA-surfactant complexes is discussed. It is shown that the trans isomer plays a major role in the DNA compaction process. The influence of the cis isomer on the DNA coil configuration is rather small. The construction of a phase diagram of the DNA concentration versus surfactant/DNA charge ratio allows distancing between three major phases: colloidally stable and unstable compacted globules, and extended coil conformation. There is a critical concentration of DNA above which the compacted globules can be hindered from aggregation and precipitation by adding an appropriate amount of the surfactant in the trans configuration. This is because of the compensation of hydrophobicity of the globules with an increasing amount of the surfactant. Below the critical DNA concentration, the compacted globules are colloidally stable and can be reversibly transferred with light to an extended coil state.

  14. Remarks on impact shearing

    Science.gov (United States)

    Klepaczko, J. R.

    1998-10-01

    A review is presented on recent progress in shear testing of materials at high and very high strain rates. Some experimental techniques are discussed which allow for materials testing in shear up to 10 6 ls. More detailed informations are provided on experimental techniques based on the Modified Double Shear specimen loaded by direct impact. This technique has been applied so far to test a variety of materials, including construction, armor and inoxidable steels, and also aluminum alloys. The double shear configuration has also been applied to test sheet metals, mostly used in the automotive industry, in a wide range of strain rates. Details of both techniques, including measuring systems and elastic wave propagation in tubes, are discussed. In addition, a new experimental configuration which can be applied for experimental studies of adiabatic shear propagation and high speed machining is discussed. The role of adiabatic heating at different rates of shearing is also discussed, including transition from pure isothermal to pure adiabatic deformation. It appears that the initial impact velocity is an important parameter in development of plastic localization. Finally, a new development is discussed in determination of the Critical Impact Velocity in shear. A comparison is shown between recent experimental findings and a simple analytic estimation. The CIV in shear is a certain mode of adiabatic failure which occurs at relatively high shear velocities of adjacent material layers. Numerical simulations support the existence of the CIV in shear which can be recognized to some extent as a material constant.

  15. Compaction behaviour of soils

    OpenAIRE

    Kurucuk, Nurses

    2017-01-01

    Soil compaction is widely applied in geotechnical engineering practice. It is used to maximise the dry density of soils to reduce subsequent settlement under working loads or to reduce the permeability of soils. The durability and stability of structures are highly related to the appropriate compaction achievement. The structural failure of roads and airfields, and the damage caused by foundation settlement can often be traced back to the failure in achieving adequate compaction. For that rea...

  16. Self-Compacting Concrete

    OpenAIRE

    Okamura, Hajime; Ouchi, Masahiro

    2003-01-01

    Self-compacting concrete was first developed in 1988 to achieve durable concrete structures. Since then, various investigations have been carried out and this type of concrete has been used in practical structures in Japan, mainly by large construction companies. Investigations for establishing a rational mix-design method and self-compactability testing methods have been carried out from the viewpoint of making self-compacting concrete a standard concrete.

  17. Textural Dependence of Shear Strength and Consolidation of ...

    African Journals Online (AJOL)

    The pH, sulphate content, specific gravity, particle size distribution, consistency limits, compaction and consolidation tests of these wastes were first carried out. Direct shear ... than the minestone. The results showed that the wastes are good for subgrade, sub-base, filling, and for earth dam and embankment construction.

  18. influence of molding water content on shear strength characteristic

    African Journals Online (AJOL)

    eobe

    INFLUENCE OF MOLDING WATER CONTENT ON SHEAR STRENGTH OF COMPACTED CEMENT KILN DUST, K. J. Osinub. K. J. Osinub. K. J. Osinubi, et al. Nigerian Journal of Technology,. Vol. 34, No. 2, April 2015 267 pavements or as waste containment materials. Therefore, recent studies have been geared towards.

  19. Influence of Molding Water Content on Shear Strength Characteristic ...

    African Journals Online (AJOL)

    A laboratory investigation was carried out to determine the shear strength characteristics of compacted cement kiln dust treated lateritic soils for use in liners and covers with up to 12.5% cement kiln dust by dry weight of soil. Specimens were prepared at molding water contents of -2, 0, +2 and +4% of the optimum moisture ...

  20. Pharmaceutical powder compaction technology

    National Research Council Canada - National Science Library

    Çelik, Metin

    2011-01-01

    "Revised to reflect modern pharmaceutical compacting techniques, this Second Edition guides pharmaceutical engineers, formulation scientists, and product development and quality assurance personnel...

  1. Compact Polarimetry Potentials

    Science.gov (United States)

    Truong-Loi, My-Linh; Dubois-Fernandez, Pascale; Pottier, Eric

    2011-01-01

    The goal of this study is to show the potential of a compact-pol SAR system for vegetation applications. Compact-pol concept has been suggested to minimize the system design while maximize the information and is declined as the ?/4, ?/2 and hybrid modes. In this paper, the applications such as biomass and vegetation height estimates are first presented, then, the equivalence between compact-pol data simulated from full-pol data and compact-pol data processed from raw data as such is shown. Finally, a calibration procedure using external targets is proposed.

  2. Shear Thinning in Xenon

    Science.gov (United States)

    Bergm Robert F.; Moldover, Michael R.; Yao, Minwu; Zimmerli, Gregory A.

    2009-01-01

    We measured shear thinning, a viscosity decrease ordinarily associated with complex liquids such as molten plastics or ketchup, near the critical point of xenon. The data span a wide range of dimensionless shear rate: the product of the shear rate and the relaxation time of critical fluctuations was greater than 0.001 and was less than 700. As predicted by theory, shear thinning occurred when this product was greater than 1. The measurements were conducted aboard the Space Shuttle Columbia to avoid the density stratification caused by Earth's gravity.

  3. Evidence of Shear-Induced Fluid Fracture in Telechelic Polymer Networks

    Energy Technology Data Exchange (ETDEWEB)

    Berret, J.-F.; Serero, Y.

    2001-07-23

    The shear-flow properties of telechelic polymer networks have been investigated by rheology and flow-visualization techniques. The steady-shear viscosity versus shear-rate curves exhibits two main branches separated by a discontinuity. One branch of the flow curve is Newtonian and shear thickening, whereas the second one is shear thinning. Above the discontinuity, shear induces a fluid fracture similar to those reported for brittle solids and at the origin of an inhomogeneous flow. Because of the finite relaxation time of the polymer network however, and contrary to ordinary gels, the fracture can be created and healed reversibly.

  4. Reverse Osmosis

    Indian Academy of Sciences (India)

    ment of Civil Engineering and is presently the. Chairman of Center for. Sustainable Technologies,. Indian Institute of Science,. Bangalore. His research areas include, unsaturated soil behaviour, hazardous waste management, water quality and remediation of contaminated water. Keywords. Osmosis, reverse osmosis,.

  5. Reversible Sterilization

    Science.gov (United States)

    Largey, Gale

    1977-01-01

    Notes that difficult questions arise concerning the use of sterilization for alleged eugenic and euthenic purposes. Thus, how reversible sterilization will be used with relation to the poor, mentally ill, mentally retarded, criminals, and minors, is questioned. (Author/AM)

  6. Formation of a compact toroid for enhanced efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Mozgovoy, A. G. [P.N. Lebedev Physical Institute, Moscow 119991 (Russian Federation); Romadanov, I. V.; Ryzhkov, S. V., E-mail: ryzhkov@power.bmstu.ru [Bauman Moscow State Technical University, Moscow 105005 (Russian Federation)

    2014-02-15

    We report here our results on the formation of a plasma configuration with the generic name of compact toroid (CT). A method of compact toroid formation to confine, heat and compress a plasma is investigated. Formation of a compact torus using an additional toroidal magnetic field helps to increase the plasma current to a maintainable level of the original magnetic field. We design the Compact Toroid Challenge (CTC) experiment in order to improve the magnetic flux trapping during field reversal in the formation of a compact toroid. The level of the magnetic field immersed in the plasma about 70% of the primary field is achieved. The CTC device and scheme of high level capturing of magnetic flux are presented.

  7. Relationship between types of surface shear stress profiles and membrane fouling.

    Science.gov (United States)

    Chan, C C V; Bérubé, P R; Hall, E R

    2011-12-01

    Shear stress has been recognized as an important parameter in controlling particle back-transport from membrane surfaces. However, little is known of the relationship between transient shear conditions induced by air sparging and fouling control near membrane surfaces. In this paper, the different types of surface shear stress profiles that had beneficial effects on minimizing reversible surface fouling were examined. The relationship between different statistical shear parameters (e.g. time-averaged shear, standard deviation of shear and amplitude of shear) and fouling control that have been used by others were examined as well. It was found that the fouling rate for membranes subjected to transient shear conditions was lower than for membranes subjected to constant shear conditions. The magnitude, duration and frequency of the shear conditions were found to have an impact on the fouling rate of membranes. It was also found that although some statistical shear parameters could generally be used to relate shear and fouling, they were inadequate to relate surface shear stress to fouling, for all transient shear conditions examined. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Compaction of FGD-gypsum

    NARCIS (Netherlands)

    Stoop, B.T.J.; Larbi, J.A.; Heijnen, W.M.M.

    1996-01-01

    It is shown that it is possible to produce compacted gypsum with a low porosity and a high strength on a laboratory scale by uniaxial compaction of flue gas desulphurization (FGD-) gypsum powder. Compacted FGD-gypsum cylinders were produced at a compaction pres-sure between 50 and 500 MPa yielding

  9. Inhomogeneous compact extra dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Bronnikov, K.A. [Center of Gravity and Fundamental Metrology, VNIIMS, 46 Ozyornaya st., Moscow 119361 (Russian Federation); Budaev, R.I.; Grobov, A.V.; Dmitriev, A.E.; Rubin, Sergey G., E-mail: kb20@yandex.ru, E-mail: buday48@mail.ru, E-mail: alexey.grobov@gmail.com, E-mail: alexdintras@mail.ru, E-mail: sergeirubin@list.ru [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), 115409 Moscow (Russian Federation)

    2017-10-01

    We show that an inhomogeneous compact extra space possesses two necessary features— their existence does not contradict the observable value of the cosmological constant Λ{sub 4} in pure f ( R ) theory, and the extra dimensions are stable relative to the 'radion mode' of perturbations, the only mode considered. For a two-dimensional extra space, both analytical and numerical solutions for the metric are found, able to provide a zero or arbitrarily small Λ{sub 4}. A no-go theorem has also been proved, that maximally symmetric compact extra spaces are inconsistent with 4D Minkowski space in the framework of pure f ( R ) gravity.

  10. Insulation irradiation test programme for the Compact Ignition Tokamak

    International Nuclear Information System (INIS)

    McManamy, T.J.; Kanemoto, G.; Snook, P.

    1991-01-01

    In a programme to evaluate the effects of radiation exposure on the electrical insulation for the toroidal field coils of the Compact Ignition Tokamak, three types of boron-free insulation were irradiated at room temperature in the Advanced Technology Reactor (ATR) and tested at the Idaho National Engineering Laboratory. The materials were Spaulrad-S, Shikishima PG5-1 and Shikishima PG3-1. The first two use a bismaleimide resin and the third an aromatic amine hardened epoxy. Spaulrad-S is a two-dimensional (2-D) weave of S-glass, while the others are 3-D weaves of T-glass. Flexure and shear/compression samples were irradiated to ≅ 5 x 10 9 and 3 x 10 10 rad with 35-40% of the total dose from neutrons. The shear/compression samples were tested in pairs by applying an average compression of 345 MPa and then a shear load. After static tests were completed, fatigue testing was performed by cycling the shear load for up to 30000 cycles with a constant compression. The static shear strength of the samples that did not fail was then determined. Generally, shear strengths of the order of 120 MPa were measured. The behaviour of the flexure and shear/compression samples was significantly different; large reductions in the flexure strength were observed, while the shear strength stayed the same or increased slightly. The 3-D weave material demonstrated higher strength and significantly less radiation damage than the 2-D material in flexure but performed almost identically when tested with combined shear and compression. The epoxy system was much more sensitive to fatigue damage than the bismaleimide materials. No swelling was measured; however, the epoxy samples did twist slightly. (author)

  11. Reverse Osmosis

    Indian Academy of Sciences (India)

    or the water reaches the tip of every leaf of a plant is due to osmotic pressure. ... concentration and temperature of the solution by a law that is similar to the gas law. ... waste management, water quality and remediation of contaminated water. Keywords. Osmosis, reverse osmosis, desalinatiion, seawater, water purification.

  12. Displacement-length scaling of brittle faults in ductile shear.

    Science.gov (United States)

    Grasemann, Bernhard; Exner, Ulrike; Tschegg, Cornelius

    2011-11-01

    Within a low-grade ductile shear zone, we investigated exceptionally well exposed brittle faults, which accumulated antithetic slip and rotated into the shearing direction. The foliation planes of the mylonitic host rock intersect the faults approximately at their centre and exhibit ductile reverse drag. Three types of brittle faults can be distinguished: (i) Faults developing on pre-existing K-feldspar/mica veins that are oblique to the shear direction. These faults have triclinic flanking structures. (ii) Wing cracks opening as mode I fractures at the tips of the triclinic flanking structures, perpendicular to the shear direction. These cracks are reactivated as faults with antithetic shear, extend from the parent K-feldspar/mica veins and form a complex linked flanking structure system. (iii) Joints forming perpendicular to the shearing direction are deformed to form monoclinic flanking structures. Triclinic and monoclinic flanking structures record elliptical displacement-distance profiles with steep displacement gradients at the fault tips by ductile flow in the host rocks, resulting in reverse drag of the foliation planes. These structures record one of the greatest maximum displacement/length ratios reported from natural fault structures. These exceptionally high ratios can be explained by localized antithetic displacement along brittle slip surfaces, which did not propagate during their rotation during surrounding ductile flow.

  13. Displacement–length scaling of brittle faults in ductile shear

    Science.gov (United States)

    Grasemann, Bernhard; Exner, Ulrike; Tschegg, Cornelius

    2011-01-01

    Within a low-grade ductile shear zone, we investigated exceptionally well exposed brittle faults, which accumulated antithetic slip and rotated into the shearing direction. The foliation planes of the mylonitic host rock intersect the faults approximately at their centre and exhibit ductile reverse drag. Three types of brittle faults can be distinguished: (i) Faults developing on pre-existing K-feldspar/mica veins that are oblique to the shear direction. These faults have triclinic flanking structures. (ii) Wing cracks opening as mode I fractures at the tips of the triclinic flanking structures, perpendicular to the shear direction. These cracks are reactivated as faults with antithetic shear, extend from the parent K-feldspar/mica veins and form a complex linked flanking structure system. (iii) Joints forming perpendicular to the shearing direction are deformed to form monoclinic flanking structures. Triclinic and monoclinic flanking structures record elliptical displacement–distance profiles with steep displacement gradients at the fault tips by ductile flow in the host rocks, resulting in reverse drag of the foliation planes. These structures record one of the greatest maximum displacement/length ratios reported from natural fault structures. These exceptionally high ratios can be explained by localized antithetic displacement along brittle slip surfaces, which did not propagate during their rotation during surrounding ductile flow. PMID:26806996

  14. Plasticity Approach to Shear Design

    DEFF Research Database (Denmark)

    Hoang, Cao Linh; Nielsen, Mogens Peter

    1998-01-01

    The paper presents some plastic models for shear design of reinforced concrete beams. Distinction is made between two shear failure modes, namely web crushing and crack sliding. The first mentioned mode is met in beams with large shear reinforcement degrees. The mode of crack sliding is met in non......-shear reinforced beams as well as in lightly shear reinforced beams. For such beams the shear strength is determined by the recently developed crack sliding model. This model is based upon the hypothesis that cracks can be transformed into yield lines, which have lower sliding resistance than yield lines formed...

  15. Real Compact Surfaces

    Indian Academy of Sciences (India)

    The classification of real compact surfaces is a main result which is at the same time easy to understand and non- trivial, simple in formulation and rich in consequences. The aim of this article is to explain the theorem by means of many drawings. It is an invitation to a visual approach of mathematics. First Definitions and ...

  16. Hadrons in compact stars

    Indian Academy of Sciences (India)

    physics pp. 817–825. Hadrons in compact stars. DEBADES BANDYOPADHYAY. Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata 700 064, India ... There is a growing interplay between the physics of dense matter in relativistic .... Kaplan and Nelson [7] first showed in a chiral SU(3)L × SU(3)R model that.

  17. Sheared Electroconvective Instability

    Science.gov (United States)

    Kwak, Rhokyun; Pham, Van Sang; Lim, Kiang Meng; Han, Jongyoon

    2012-11-01

    Recently, ion concentration polarization (ICP) and related phenomena draw attention from physicists, due to its importance in understanding electrochemical systems. Researchers have been actively studying, but the complexity of this multiscale, multiphysics phenomenon has been limitation for gaining a detailed picture. Here, we consider electroconvective(EC) instability initiated by ICP under pressure-driven flow, a scenario often found in electrochemical desalinations. Combining scaling analysis, experiment, and numerical modeling, we reveal unique behaviors of sheared EC: unidirectional vortex structures, its size selection and vortex propagation. Selected by balancing the external pressure gradient and the electric body force, which generates Hagen-Poiseuille(HP) flow and vortical EC, the dimensionless EC thickness scales as (φ2 /UHP)1/3. The pressure-driven flow(or shear) suppresses unfavorably-directed vortices, and simultaneously pushes favorably-directed vortices with constant speed, which is linearly proportional to the total shear of HP flow. This is the first systematic characterization of sheared EC, which has significant implications on the optimization of electrodialysis and other electrochemical systems.

  18. Sheared solid materials

    Indian Academy of Sciences (India)

    cores eventually breaks the Peierls potential leading to slow relaxations in the stress and the free energy (aging). .... Figure 1 displays the stress–strain curves at constant shear rate ˙γ applied for t > 0 in units of µ0 and τ−1 ..... In particular, the slow structural relaxations evidently arise from migration of the free volume.

  19. Compaction and Porosity Based Pore Pressure Prediction in the ...

    African Journals Online (AJOL)

    2: A reversal in the trend (well 3; 5450-9658ft, r = -0.89) indicated by an increase in porosity as a result of overpressure. A number of factors such as compaction, fluid content and pore pressure affect the porosity-depth trends of the Agbada Formation. A decrease in porosity with depth generally holds true for shales (well 1: ...

  20. Theoretical studies of non inductive current drive in compact toroids

    NARCIS (Netherlands)

    Farengo, R; Lifschitz, AF; Caputi, KI; Arista, NR; Clemente, RA

    Three non inductive current drive methods that can be applied to compact toroids axe studied. The use of neutral beams to drive current in field reversed configurations and spheromaks is studied using a Monte Carlo code that includes a complete ionization package and follows the exact particle

  1. Shear heating by translational brittle reverse faulting along a single ...

    Indian Academy of Sciences (India)

    Department of Earth Sciences, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India. e-mail: soumyajitm@gmail.com .... The equation of transient heat flow for a homo- geneous solid whose conductivity does not .... The role of frictional heating and hydraulic diffusivity;. Geophys. Res. Lett. 34 L07301.

  2. Shear heating by translational brittle reverse faulting along a single ...

    Indian Academy of Sciences (India)

    structures of fault zones (Lamb 2006). Such stud- ies are also important to understand the genesis of pseudotachylites (Vernon and Clarke 2008) that may be present along faults (Rice and Cocco 2005), fault kinematics (e.g., Sibson 2002), thermal soft- ening during deformation (Blanpied et al. 1998), etc. (also see Segall ...

  3. Reversible Statistics

    DEFF Research Database (Denmark)

    Tryggestad, Kjell

    2004-01-01

    The study aims is to describe how the inclusion and exclusion of materials and calculative devices construct the boundaries and distinctions between statistical facts and artifacts in economics. My methodological approach is inspired by John Graunt's (1667) Political arithmetic and more recent work...... within constructivism and the field of Science and Technology Studies (STS). The result of this approach is here termed reversible statistics, reconstructing the findings of a statistical study within economics in three different ways. It is argued that all three accounts are quite normal, albeit...... by accounting for the significance of the materials and the equipment that enters into the production of statistics. Key words: Reversible statistics, diverse materials, constructivism, economics, science, and technology....

  4. Investigating the Effect of Compaction Characteristics on the Erodibility of Cohesive Soils Using the JET Method

    Science.gov (United States)

    Asghari Tabrizi, A.; LaRocque, L. A.; Chaudhry, M.; Imran, J.

    2013-12-01

    Several flood disasters occur every year all over the world, mostly due to levee and dam failure which result in human fatalities as well as devastating economic damages. To model and predict earthen embankment failures for the preparation of emergency action plans and risk assessments, the soil erodibility by flowing water is an essential parameter. The determination of erodibility becomes even more complicated for cohesive soils because of the large number of parameters controlling their erosion behavior (e.g. clay content, plasticity, compaction effort, compaction water content) and the difficulty of estimating these parameters. In this study the effect of the compaction energy and compaction water content on the erodibility of a sandy loam soil was assessed. Soil samples were prepared in a standard diameter compaction mold, 101.6 mm, for three levels of compaction effort and water content (i.e. low, medium, and high) with two replications for each case (18 tests total) and examined using the jet erosion test (JET). Observations from qualitative and statistical analyses of the data are: 1) a wide range of erodibility, from very erodible to very resistant, was produced by changes in the compaction characteristics; 2) for a given compaction energy, the erosion resistance based on the detachment rate coefficient kd tends to become minimum near the optimum compaction water content. On the dry side of optimum compaction water content, kd decreases with steep gradients by increasing the water content, while it increases with a flatter gradient on the wet side; 3) At a given water content, the soil erosion resistance increases with compaction efforts; 4) compaction water content influences soil erosibility more than compaction energy, especially on the dry side of the optimum compaction water content; and 5) for a given compaction effort, the critical shear stress increases with water content up to an optimum water content and then it decreases which is in consistent

  5. Hydrodynamic of a deformed bubble in linear shear flow

    International Nuclear Information System (INIS)

    Adoua, S.R.

    2007-07-01

    This work is devoted to the study of an oblate spheroidal bubble of prescribed shape set fixed in a linear shear flow using direct numerical simulation. The three dimensional Navier-Stokes equations are solved in orthogonal curvilinear coordinates using a finite volume method. The bubble response is studied over a wide range of the aspect ratio (1-2.7), the bubble Reynolds number (50-2000) and the non-dimensional shear rate (0.-1.2). The numerical simulations shows that the shear flow imposes a plane symmetry of the wake whatever the parameters of the flow. The trailing vorticity is organized into two anti-symmetrical counter rotating tubes with a sign imposed by the competition of two mechanisms (the Lighthill mechanism and the instability of the wake). Whatever the Reynolds number, the lift coefficient reaches the analytical value obtained in an inviscid, weakly sheared flow corresponding to a lift force oriented in the same direction as that of a spherical bubble. For moderate Reynolds numbers, the direction of the lift force reverses when the bubble aspect ratio is large enough as observed in experiments. This reversal occurs for aspect ratios larger than 2.225 and is found to be directly linked to the sign of the trailing vorticity which is concentrated within two counter-rotating threads which propel the bubble in a direction depending of their sign of rotation. The behavior of the drag does not revel any significant effect induced by the wake structure and follows a quadratic increase with the shear rate. Finally, the torque experienced by the bubble also reverses for the same conditions inducing the reversal of the lift force. By varying the orientation of the bubble in the shear flow, a stable equilibrium position is found corresponding to a weak angle between the small axis of the bubble and the flow direction. (author)

  6. The Capacity for Compaction Weakening in Fault Gouge in Nature and Experiment

    Science.gov (United States)

    Faulkner, D.; Boulton, C. J.; Sanchez Roa, C.; Den Hartog, S. A. M.; Bedford, J. D.

    2017-12-01

    As faults form in low permeability rocks, the compaction of fault gouge can lead to significant pore-fluid pressure increases. The pore pressure increase results from the collapse of the porosity through shear-enhanced compaction and the low hydraulic diffusivity of the gouge that inhibits fluid flow. In experiments, the frictional properties of clay-bearing fault gouges are significantly affected by the development of locally high pore-fluid pressures when compaction rates are high due to fast displacement rates or slip in underconsolidated materials. We show how the coefficient of friction of fault gouges sheared at different slip velocities can be explained with a numerical model that is constrained by laboratory measurements of contemporaneous changes in permeability and porosity. In nature, for compaction weakening to play an important role in earthquake nucleation (and rupture propagation), a mechanism is required to reset the porosity, i.e., maintain underconsolidated gouge along the fault plane. We use the observations of structures within the principal slip zone of the Alpine Fault in New Zealand to suggest that cyclic fluidization of the gouge occurs during coseismic slip, thereby resetting the gouge porosity prior to the next seismic event. Results from confined laboratory rotary shear measurements at elevated slip rates appear to support the hypothesis that fluidization leads to underconsolidation and, thus, to potential weakening by shear-enhanced compaction-induced pore-fluid pressurization.

  7. Soft b-compact spaces

    Directory of Open Access Journals (Sweden)

    Alkan Özkan

    2016-04-01

    Full Text Available In this paper, a new class of generalized soft open sets in soft generalized topological spaces as a generalization of compact spaces, called soft b-compact spaces, is introduced and studied. A soft generalized topological space is soft b-compact if every soft b-open soft cover of (F,E contains a finite soft subcover. We characterize soft b-compact space and study some of their basic properties.

  8. Weakly compact operators and interpolation

    OpenAIRE

    Maligranda, Lech

    1992-01-01

    The class of weakly compact operators is, as well as the class of compact operators, a fundamental operator ideal. They were investigated strongly in the last twenty years. In this survey, we have collected and ordered some of this (partly very new) knowledge. We have also included some comments, remarks and examples. The class of weakly compact operators is, as well as the class of compact operators, a fundamental operator ideal. They were investigated strongly in the last twenty years. I...

  9. Experiments on sheet metal shearing

    OpenAIRE

    Gustafsson, Emil

    2013-01-01

    Within the sheet metal industry, different shear cutting technologies are commonly used in several processing steps, e.g. in cut to length lines, slitting lines, end cropping etc. Shearing has speed and cost advantages over competing cutting methods like laser and plasma cutting, but involves large forces on the equipment and large strains in the sheet material.Numerical models to predict forces and sheared edge geometry for different sheet metal grades and different shear parameter set-ups a...

  10. Analysis of laboratory compaction methods of roller compacted concrete

    Science.gov (United States)

    Trtík, Tomáš; Chylík, Roman; Bílý, Petr; Fládr, Josef

    2017-09-01

    Roller-Compacted Concrete (RCC) is an ordinary concrete poured and compacted with machines typically used for laying of asphalt road layers. One of the problems connected with this technology is preparation of representative samples in the laboratory. The aim of this work was to analyse two methods of preparation of RCC laboratory samples with bulk density as the comparative parameter. The first method used dynamic compaction by pneumatic hammer. The second method of compaction had a static character. The specimens were loaded by precisely defined force in laboratory loading machine to create the same conditions as during static rolling (in the Czech Republic, only static rolling is commonly used). Bulk densities obtained by the two compaction methods were compared with core drills extracted from real RCC structure. The results have shown that the samples produced by pneumatic hammer tend to overestimate the bulk density of the material. For both compaction methods, immediate bearing index test was performed to verify the quality of compaction. A fundamental difference between static and dynamic compaction was identified. In static compaction, initial resistance to penetration of the mandrel was higher, after exceeding certain limit the resistance was constant. This means that the samples were well compacted just on the surface. Specimens made by pneumatic hammer actively resisted throughout the test, the whole volume was uniformly compacted.

  11. Compact Spreader Schemes

    Energy Technology Data Exchange (ETDEWEB)

    Placidi, M.; Jung, J. -Y.; Ratti, A.; Sun, C.

    2014-07-25

    This paper describes beam distribution schemes adopting a novel implementation based on low amplitude vertical deflections combined with horizontal ones generated by Lambertson-type septum magnets. This scheme offers substantial compactness in the longitudinal layouts of the beam lines and increased flexibility for beam delivery of multiple beam lines on a shot-to-shot basis. Fast kickers (FK) or transverse electric field RF Deflectors (RFD) provide the low amplitude deflections. Initially proposed at the Stanford Linear Accelerator Center (SLAC) as tools for beam diagnostics and more recently adopted for multiline beam pattern schemes, RFDs offer repetition capabilities and a likely better amplitude reproducibility when compared to FKs, which, in turn, offer more modest financial involvements both in construction and operation. Both solutions represent an ideal approach for the design of compact beam distribution systems resulting in space and cost savings while preserving flexibility and beam quality.

  12. Compact spreader schemes

    Energy Technology Data Exchange (ETDEWEB)

    Placidi, M.; Jung, J.-Y.; Ratti, A.; Sun, C., E-mail: csun@lbl.gov

    2014-12-21

    This paper describes beam distribution schemes adopting a novel implementation based on low amplitude vertical deflections combined with horizontal ones generated by Lambertson-type septum magnets. This scheme offers substantial compactness in the longitudinal layouts of the beam lines and increased flexibility for beam delivery of multiple beam lines on a shot-to-shot basis. Fast kickers (FK) or transverse electric field RF Deflectors (RFD) provide the low amplitude deflections. Initially proposed at the Stanford Linear Accelerator Center (SLAC) as tools for beam diagnostics and more recently adopted for multiline beam pattern schemes, RFDs offer repetition capabilities and a likely better amplitude reproducibility when compared to FKs, which, in turn, offer more modest financial involvements both in construction and operation. Both solutions represent an ideal approach for the design of compact beam distribution systems resulting in space and cost savings while preserving flexibility and beam quality.

  13. Compact stellarators as reactors

    International Nuclear Information System (INIS)

    Lyon, J.F.; Valanju, P.; Zarnstorff, M.C.; Hirshman, S.; Spong, D.A.; Strickler, D.; Williamson, D.E.; Ware, A.

    2001-01-01

    Two types of compact stellarators are examined as reactors: two- and three-field-period (M=2 and 3) quasi-axisymmetric devices with volume-average =4-5% and M=2 and 3 quasi-poloidal devices with =10-15%. These low-aspect-ratio stellarator-tokamak hybrids differ from conventional stellarators in their use of the plasma-generated bootstrap current to supplement the poloidal field from external coils. Using the ARIES-AT model with B max =12T on the coils gives Compact Stellarator reactors with R=7.3-8.2m, a factor of 2-3 smaller R than other stellarator reactors for the same assumptions, and neutron wall loadings up to 3.7MWm -2 . (author)

  14. Compact fusion reactors

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    Fusion research is currently to a large extent focused on tokamak (ITER) and inertial confinement (NIF) research. In addition to these large international or national efforts there are private companies performing fusion research using much smaller devices than ITER or NIF. The attempt to achieve fusion energy production through relatively small and compact devices compared to tokamaks decreases the costs and building time of the reactors and this has allowed some private companies to enter the field, like EMC2, General Fusion, Helion Energy, Lawrenceville Plasma Physics and Lockheed Martin. Some of these companies are trying to demonstrate net energy production within the next few years. If they are successful their next step is to attempt to commercialize their technology. In this presentation an overview of compact fusion reactor concepts is given.

  15. Shear Behavior of Concrete Beams Reinforced with GFRP Shear Reinforcement

    Directory of Open Access Journals (Sweden)

    Heecheul Kim

    2015-01-01

    Full Text Available This paper presents the shear capacities of concrete beams reinforced with glass fiber reinforced polymer (GFRP plates as shear reinforcement. To examine the shear performance, we manufactured and tested a total of eight specimens. Test variables included the GFRP strip-width-to-spacing ratio and type of opening array. The specimen with a GFRP plate with a 3×2 opening array showed the highest shear strength. From the test results, the shear strength increased as the strip-width-to-strip-spacing ratio increased. Also, we used the experimental results to evaluate whether the shear strength equations of ACI 318-14 and ACI 440.1R can be applied to the design of GFRP shear reinforcement. In the results, the ACI 440 equation underestimated the experimental results more than that of ACI 318.

  16. Compact SAW aerosol generator

    OpenAIRE

    Winkler, A.; Harazim, S.; Collins, D.J.; Br?nig, R.; Schmidt, H.; Menzel, S.B.

    2017-01-01

    In this work, we discuss and demonstrate the principle features of surface acoustic wave (SAW) aerosol generation, based on the properties of the fluid supply, the acoustic wave field and the acoustowetting phenomena. Furthermore, we demonstrate a compact SAW-based aerosol generator amenable to mass production fabricated using simple techniques including photolithography, computerized numerical control (CNC) milling and printed circuit board (PCB) manufacturing. Using this device, we present ...

  17. Shear-thinning Fluid

    Science.gov (United States)

    2001-01-01

    Whipped cream and the filling for pumpkin pie are two familiar materials that exhibit the shear-thinning effect seen in a range of industrial applications. It is thick enough to stand on its own atop a piece of pie, yet flows readily when pushed through a tube. This demonstrates the shear-thinning effect that was studied with the Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002. CVX observed the behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. The principal investigator was Dr. Robert Berg of the National Institutes of Standards and Technology in Gaithersburg, MD.

  18. Forflytning: shear og friktion

    DEFF Research Database (Denmark)

    2005-01-01

    friktion). Formålet med filmprojektet er: At give personalet i Apopleksiafsnittet viden om shear og friktion, så det motiveres til forebyggelse. Mål At udarbejde et enkelt undervisningsmateriale til bed-side-brug Projektbeskrivelse (resume) Patienter med apopleksi er særligt udsatte for tryksår, fordi de...... ofte er immobile, har svært ved at opretholde en god siddestilling eller ligger tungt i sengen som følger efter apopleksien Hvis personalet bruger forkert lejrings-og forflytningsteknik, udsættes patienterne for shear og friktion. Målgruppen i projektet er de personer, der omgås patienterne, dvs...

  19. Shear Roll Mill Reactivation

    Science.gov (United States)

    2012-09-13

    pneumatically operated paste dumper and belt conveyor system , the loss in weight feeder system , the hydraulically operated shear roll mill, the pellet...out feed belt conveyor , and the pack out system comprised of the metal detector, scale, and pack out empty and full drum roller conveyors . Page | 4...process equipment sprinkler protection systems , and the 5 psig steam supply serving the building heating and make-up air systems . It also included

  20. Effects of dynamic shear and transmural pressure on wall shear stress sensitivity in collecting lymphatic vessels

    Science.gov (United States)

    Kornuta, Jeffrey A.; Nepiyushchikh, Zhanna; Gasheva, Olga Y.; Mukherjee, Anish; Zawieja, David C.

    2015-01-01

    Given the known mechanosensitivity of the lymphatic vasculature, we sought to investigate the effects of dynamic wall shear stress (WSS) on collecting lymphatic vessels while controlling for transmural pressure. Using a previously developed ex vivo lymphatic perfusion system (ELPS) capable of independently controlling both transaxial pressure gradient and average transmural pressure on an isolated lymphatic vessel, we imposed a multitude of flow conditions on rat thoracic ducts, while controlling for transmural pressure and measuring diameter changes. By gradually increasing the imposed flow through a vessel, we determined the WSS at which the vessel first shows sign of contraction inhibition, defining this point as the shear stress sensitivity of the vessel. The shear stress threshold that triggered a contractile response was significantly greater at a transmural pressure of 5 cmH2O (0.97 dyne/cm2) than at 3 cmH2O (0.64 dyne/cm2). While contraction frequency was reduced when a steady WSS was applied, this inhibition was reversed when the applied WSS oscillated, even though the mean wall shear stresses between the conditions were not significantly different. When the applied oscillatory WSS was large enough, flow itself synchronized the lymphatic contractions to the exact frequency of the applied waveform. Both transmural pressure and the rate of change of WSS have significant impacts on the contractile response of lymphatic vessels to flow. Specifically, time-varying shear stress can alter the inhibition of phasic contraction frequency and even coordinate contractions, providing evidence that dynamic shear could play an important role in the contractile function of collecting lymphatic vessels. PMID:26333787

  1. A method for manufacturing compacts

    International Nuclear Information System (INIS)

    Baschwitz, Robert; Raymond, Jean.

    1974-01-01

    Description is given of a method for preparing compacts with high matrix density. The method is characterized by the steps of forming the mixture by simultaneously pouring the components directly into a compacting matrix comprising coated particles and a graphite binder mixture in the granular form, then compressing the compact after having brought the material to be compacted to a temperature at which the binder is in the fluid state. The method can be applied to the manufacture of compacts for high temperature nuclear reactors [fr

  2. Magnetic reversals from planetary dynamo waves

    DEFF Research Database (Denmark)

    Sheyko, Andrey; Finlay, Chris; Jackson, Andrew

    2016-01-01

    A striking feature of many natural dynamos is their ability to undergo polarity reversals. The best documented example is Earth's magnetic field, which has reversed hundreds of times during its history. The origin of geomagnetic polarity reversals lies in a magnetohydrodynamic process that takes...... place in Earth's core, but the precise mechanism is debated. The majority of numerical geodynamo simulations that exhibit reversals operate in a regime in which the viscosity of the fluid remains important, and in which the dynamo mechanism primarily involves stretching and twisting of field lines...... (the ratio of advection to Coriolis force). Instead, stretching of the magnetic field by a strong shear in the east-west flow near the imaginary cylinder just touching the inner core and parallel to the axis of rotation is crucial to the reversal mechanism in our models, which involves a process akin...

  3. Diffusion through statically compacted clay

    International Nuclear Information System (INIS)

    Ho, C.L.; Shebl, M.A.A.

    1994-01-01

    This paper presents experimental work on the effect of compaction on contaminant flow through clay liners. The experimental program included evaluation of soil properties, compaction, permeability and solute diffusion. A permeameter was built of non reactive materials to test samples compacted at different water contents and compactive efforts. The flow of a permeating solute, LiCl, was monitored. Effluent samples were collected for solute concentration measurements. The concentrations were measured by performing atomic adsorption tests. The analyzed results showed different diffusion characteristics when compaction conditions changed. At each compactive effort, permeability decreased as molding water content increased. Consequently, transit time (measured at relative concentration 50%) increased and diffusivity decreased. As compactive effort increased for soils compacted dry of optimum, permeability and diffusion decreased. On the other hand, as compactive effort increased for soils compacted wet of optimum, permeability and diffusivity increased. Tortuosity factor was indirectly measured from the diffusion and retardation rate. Tortuosity factor also decreased as placement water content was increased from dry of optimum to wet of optimum. Then decreases were more pronounced for low compactive effort tests. 27 refs., 7 figs., 5 tabs

  4. Interchange stability of noncircular reversed field pinches

    International Nuclear Information System (INIS)

    Skinner, D.A.; Prager, S.C.; Todd, A.M.M.

    1987-08-01

    Interchange (Mercier) stability of toroidal reversed-field-pinch plasmas with noncircular cross-section is evaluated numerically. Marginally stable pressure profiles and beta values are produced. Most shapes, such as indented or vertically elongated, reduce stability by making the net magnetic curvature of the poloidal-field-dominated plasmas yet worse than that of the circle. Horizontally elongated plasmas slightly enhance stability beyond that of the circle as a result of increased shear produced by toroidicity. Such shear enhancement by the toroidal shift of magnetic surfaces might be exploited for future, more comprehensive studies

  5. Reversible Statistics

    DEFF Research Database (Denmark)

    Tryggestad, Kjell

    2004-01-01

    The study aims is to describe how the inclusion and exclusion of materials and calculative devices construct the boundaries and distinctions between statistical facts and artifacts in economics. My methodological approach is inspired by John Graunt's (1667) Political arithmetic and more recent work...... within constructivism and the field of Science and Technology Studies (STS). The result of this approach is here termed reversible statistics, reconstructing the findings of a statistical study within economics in three different ways. It is argued that all three accounts are quite normal, albeit...... in different ways. The presence and absence of diverse materials, both natural and political, is what distinguishes them from each other. Arguments are presented for a more symmetric relation between the scientific statistical text and the reader. I will argue that a more symmetric relation can be achieved...

  6. Compact synchrotron radiation source

    International Nuclear Information System (INIS)

    Liu, N.; Wang, T.; Tian, J.; Lin, Y.; Chen, S.; He, W.; Hu, Y.; Li, Q.

    1985-01-01

    A compact 800 MeV synchrotron radiation source is discussed. The storage ring has a circumference of 30.3 m, two 90 degree and four 45 degree bending magnet sections, two long straight sections and four short straight sections. The radius of the bending magnet is 2.224m. The critical wave length is 24A. The injector is a 15 Mev Microtron Electrons are accelerated from 15 Mev to 800 Mev by ramping the field of the ring. The expected stored current will be around 100 ma

  7. Compact neutron flux monitor

    International Nuclear Information System (INIS)

    Madhavi, V.; Phatak, P.R.; Bahadur, C.; Bayala, A.K.; Jakati, R.K.; Sathian, V.

    2003-01-01

    Full text: A compact size neutron flux monitor has been developed incorporating standard boards developed for smart radiation monitors. The sensitivity of the monitors is 0.4cps/nV. It has been tested up to 2075 nV flux with standard neutron sources. It shows convincing results even in high flux areas like 6m away from the accelerator in RMC (Parel) for 106/107 nV. These monitors have a focal and remote display, alarm function with potential free contacts for centralized control and additional provision of connectivity via RS485/Ethernet. This paper describes the construction, working and results of the above flux monitor

  8. Compact Q-balls

    Energy Technology Data Exchange (ETDEWEB)

    Bazeia, D., E-mail: bazeia@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, 58051-970 João Pessoa, PB (Brazil); Losano, L.; Marques, M.A. [Departamento de Física, Universidade Federal da Paraíba, 58051-970 João Pessoa, PB (Brazil); Menezes, R. [Departamento de Ciências Exatas, Universidade Federal da Paraíba, 58297-000 Rio Tinto, PB (Brazil); Departamento de Física, Universidade Federal de Campina Grande, 58109-970 Campina Grande, PB (Brazil); Rocha, R. da [Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, 09210-580 Santo André (Brazil)

    2016-07-10

    In this work we deal with non-topological solutions of the Q-ball type in two space–time dimensions, in models described by a single complex scalar field that engenders global symmetry. The main novelty is the presence of stable Q-balls solutions that live in a compact interval of the real line and appear from a family of models controlled by two distinct parameters. We find analytical solutions and study their charge and energy, and show how to control the parameters to make the Q-balls classically and quantum mechanically stable.

  9. Compact synchrotron light sources

    CERN Document Server

    Weihreter, Ernst

    1996-01-01

    This book covers a new niche in circular accelerator design, motivated by the promising industrial prospects of recent micromanufacturing methods - X-ray lithography, synchrotron radiation-based micromachining and microanalysis techniques. It describes the basic concepts and the essential challenges for the development of compact synchrotron radiation sources from an accelerator designer's point of view and gives an outline of the actual state of the art. The volume is intended as an introduction and as a reference for physicists, engineers and managers involved in this rapidly developing fiel

  10. Negative snakes in JET: evidence for negative shear

    International Nuclear Information System (INIS)

    Gill, R.D.; Alper, B.; Edwards, A.W.

    1994-01-01

    The signature of the negative snakes from the soft X-ray cameras is very similar to the more usual snakes except that the localised region of the snake has, compared with its surroundings, decreased rather than increased emission. Circumstances where negative snakes have been seen are reviewed. The negative snake appears as a region of increased resistance and of increased impurity density. The relationship between the shear and the current perturbation is shown, and it seem probable that the magnetic shear is reversed at the point of the negative snake, i.e. that q is decreasing with radius. 6 refs., 6 figs

  11. Bone compaction enhances fixation of weight-bearing hydroxyapatite-coated implants

    DEFF Research Database (Denmark)

    Kold, Søren Vedding; Rahbek, Ole; Vestermark, Marianne Toft

    2006-01-01

    The effect of bone compaction vs conventional drilling on the fixation of hydroxyapatite-coated implants was examined in a weight-bearing canine model. In each dog, one knee joint had the implant cavity prepared with drilling, the other with compaction. Eight dogs were euthanized after 2 weeks...... and 8 dogs after 4 weeks. Femoral condyles from additional 7 dogs represented time 0. Compacted specimens had significantly higher bone implant contact and energy absorption at time 0. Compaction significantly increased ultimate shear strength at 0 and 2 weeks. There was no significant difference...... in implant fixation after 4 weeks. The results of this study suggest that compaction may be beneficial in optimizing the crucial initial implant stability, even when hydroxyapatite-coated implants with osteoconductive properties are inserted in vivo....

  12. Scalable Nonlinear Compact Schemes

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Debojyoti [Argonne National Lab. (ANL), Argonne, IL (United States); Constantinescu, Emil M. [Univ. of Chicago, IL (United States); Brown, Jed [Univ. of Colorado, Boulder, CO (United States)

    2014-04-01

    In this work, we focus on compact schemes resulting in tridiagonal systems of equations, specifically the fifth-order CRWENO scheme. We propose a scalable implementation of the nonlinear compact schemes by implementing a parallel tridiagonal solver based on the partitioning/substructuring approach. We use an iterative solver for the reduced system of equations; however, we solve this system to machine zero accuracy to ensure that no parallelization errors are introduced. It is possible to achieve machine-zero convergence with few iterations because of the diagonal dominance of the system. The number of iterations is specified a priori instead of a norm-based exit criterion, and collective communications are avoided. The overall algorithm thus involves only point-to-point communication between neighboring processors. Our implementation of the tridiagonal solver differs from and avoids the drawbacks of past efforts in the following ways: it introduces no parallelization-related approximations (multiprocessor solutions are exactly identical to uniprocessor ones), it involves minimal communication, the mathematical complexity is similar to that of the Thomas algorithm on a single processor, and it does not require any communication and computation scheduling.

  13. Insulation interlaminar shear strength testing with compression and irradiation

    International Nuclear Information System (INIS)

    McManamy, T.J.; Brasier, J.E.; Snook, P.

    1989-01-01

    The Compact Ignition Tokamak (CIT) project identified the need for research and development for the insulation to be used in the toroidal field coils. The requirements included tolerance to a combination of high compression and shear and a high radiation dose. Samples of laminate-type sheet material were obtained from commercial vendors. The materials included various combinations of epoxy, polyimide, E-glass, S-glass, and T-glass. The T-glass was in the form of a three-dimensional weave. The first tests were with 50 x 25 x 1 mm samples. These materials were loaded in compression and then to failure in shear. At 345-MPa compression, the interlaminar shear strength was generally in the range of 110 to 140 MPa for the different materials. A smaller sample configuration was developed for irradiation testing. The data before irradiation were similar to those for the larger samples but approximately 10% lower. Limited fatigue testing was also performed by cycling the shear load. No reduction in shear strength was found after 50,000 cycles at 90% of the failure stress. Because of space limitations, only three materials were chosen for irradiation: two polyimide systems and one epoxy system. All used boron-free glass. The small shear/compression samples and some flexure specimens were irradiated to 4 x 10 9 and 2 x 10 10 rad in the Advanced Technology Reactor at Idaho National Engineering Laboratory. A lead shield was used to ensure that the majority of the dose was from neutrons. The shear strength with compression before and after irradiation at the lower dose was determined. Flexure strength and the results from irradiation at the higher dose level will be available in the near future. 7 refs., 7 figs., 2 tabs

  14. NUMERICAL SIMULATION OF AN AGRICULTURAL SOIL SHEAR STRESS TEST

    Directory of Open Access Journals (Sweden)

    Andrea Formato

    2007-03-01

    Full Text Available In this work a numerical simulation of agricultural soil shear stress tests was performed through soil shear strength data detected by a soil shearometer. We used a soil shearometer available on the market to measure soil shear stress and constructed special equipment that enabled automated detection of soil shear stress. It was connected to an acquisition data system that displayed and recorded soil shear stress during the full field tests. A soil shearometer unit was used to the in situ measurements of soil shear stress in full field conditions for different types of soils located on the right side of the Sele river, at a distance of about 1 km from each other, along the perpendicular to the Sele river in the direction of the sea. Full field tests using the shearometer unit were performed alongside considered soil characteristic parameter data collection. These parameter values derived from hydrostatic compression and triaxial tests performed on considered soil samples and repeated 4 times and we noticed that the difference between the maximum and minimum values detected for every set of performed tests never exceeded 4%. Full field shear tests were simulated by the Abaqus program code considering three different material models of soils normally used in the literature, the Mohr-Coulomb, Drucker-Prager and Cam-Clay models. We then compared all data outcomes obtained by numerical simulations with those from the experimental tests. We also discussed any further simulation data results obtained with different material models and selected the best material model for each considered soil to be used in tyre/soil contact simulation or in soil compaction studies.

  15. The effect of fly ash to self-compactability of pumice aggregate ...

    Indian Academy of Sciences (India)

    when producing SCC in order to increase the workability and reduce the segregation. The con- tent of coarse aggregate and ... So, the use of pumice as aggregate or mineral additive in production of self-compacting concrete may be a good approach ..... rate and plastic viscosity of concrete. The shear stress and viscosity of ...

  16. The effect of fly ash to self-compactability of pumice aggregate ...

    Indian Academy of Sciences (India)

    concrete. In this study, pumice had been used as lightweight aggregates. Several prop- erties of self-compacting pumice aggregate lightweight concretes like the unit weight, flow diameter, T50 time, flow ..... flow diameter has increased because of shear stress and viscosity of concrete decreased. Fly ash replacing instead of ...

  17. Flexural strength of self compacting fiber reinforced concrete beams using polypropylene fiber: An experimental study

    Science.gov (United States)

    Lisantono, Ade; Praja, Baskoro Abdi; Hermawan, Billy Nouwen

    2017-11-01

    One of the methods to increase the tensile strength of concrete is adding a fiber material into the concrete. While to reduce a noise in a construction project, a self compacting concrete was a good choices in the project. This paper presents an experimental study of flexural behavior and strength of self compacting fiber reinforced concrete (RC) beams using polypropylene fiber. The micro monofilament polypropylene fibers with the proportion 0.9 kg/m3 of concrete weight were used in this study. Four beam specimens were cast and tested in this study. Two beams were cast of self compacting reinforced concrete without fiber, and two beams were cast of self compacting fiber reinforced concrete using polypropylene. The beams specimen had the section of (180×260) mm and the length was 2000 mm. The beams had simple supported with the span of 1800 mm. The longitudinal reinforcements were using diameter of 10 mm. Two reinforcements of Ø10 mm were put for compressive reinforcement and three reinforcements of Ø10 mm were put for tensile reinforcement. The shear reinforcement was using diameter of 8 mm. The shear reinforcements with spacing of 100 mm were put in the one fourth near to the support and the spacing of 150 mm were put in the middle span. Two points loading were used in the testing. The result shows that the load-carrying capacity of the self compacting reinforced concrete beam using polypropylene was a little bit higher than the self compacting reinforced concrete beam without polypropylene. The increment of load-carrying capacity of self compacting polypropylene fiber reinforced concrete was not so significant because the increment was only 2.80 % compare to self compacting non fiber reinforced concrete. And from the load-carrying capacity-deflection relationship curves show that both the self compacting polypropylene fiber reinforced concrete beam and the self compacting non fiber reinforced concrete beam were ductile beams.

  18. Magnetorheological dampers in shear mode

    International Nuclear Information System (INIS)

    Wereley, N M; Cho, J U; Choi, Y T; Choi, S B

    2008-01-01

    In this study, three types of shear mode damper using magnetorheological (MR) fluids are theoretically analyzed: linear, rotary drum, and rotary disk dampers. The damping performance of these shear mode MR dampers is characterized in terms of the damping coefficient, which is the ratio of the equivalent viscous damping at field-on status to the damping at field-off status. For these three types of shear mode MR damper, the damping coefficient or dynamic range is derived using three different constitutive models: the Bingham–plastic, biviscous, and Herschel–Bulkley models. The impact of constitutive behavior on shear mode MR dampers is theoretically presented and compared

  19. High Impact Technology Compact Combustion (HITCC) Compact Core Technologies

    Science.gov (United States)

    2016-01-01

    were combusted in a vitiated stream. The molecular weight and hydrogen -to-carbon ratios of these fuels were measured by Princeton University [17...AFRL-RQ-WP-TR-2016-0010 HIGH IMPACT TECHNOLOGY COMPACT COMBUSTION (HITCC) COMPACT CORE TECHNOLOGIES Andrew W. Caswell Combustion ...ANDREW W. CASWELL CHARLES J. CROSS, Branch Chief Program Engineer Combustion Branch Combustion Branch Turbine Engine Division Turbine

  20. Isometric coactions of compact quantum groups on compact ...

    Indian Academy of Sciences (India)

    We propose a notion of isometric coaction of a compact quantum group on a compact quantum metric space in the framework of Rieffel, where the metric structure is given by a Lipnorm. Within this setting we study the problem of the existence of a quantum isometry group.

  1. Shear strength of non-shear reinforced concrete elements

    DEFF Research Database (Denmark)

    Hoang, Cao linh

    1997-01-01

    The report deals with the shear strength of statically indeterminate reinforced concrete beams without shear reinforcement. Solutions for a number of beams with different load and support conditions have been derived by means of the crack sliding model developed by Jin- Ping Zhang.This model is b...

  2. Geometrical Aspects During Formation of Compact Aggregates of Red Blood Cells

    Directory of Open Access Journals (Sweden)

    Cardoso A.V.

    2002-01-01

    Full Text Available In the past forty years considerable progress has been achieved on the knowledge of human blood as a non-Newtonian shear-thinning suspension, whose initial state, that is at rest (stasis or at very low shear rates, has a gel-like internal structure which is destroyed as shear stress increases. The main goal of this communication is to describe the role of geometrical aspects during RBC (red blood cell aggregate formation, growth and compaction on naturally aggregate (porcine blood and non-aggregate (bovine blood samples. We consider how these aspects coupled with tension equilibrium are decisive to transform red cell linear roleaux to three-dimensional aggregates or clusters. Geometrical aspects are also crucial on the compaction of red blood cell aggregates. These densely packed aggregates could precipitate out of blood- either as dangerous deposits on arterial walls, or as clots which travel in suspension until they block some crucial capillary.

  3. The Compact Ignition Tokamak

    International Nuclear Information System (INIS)

    Schmidt, J.

    1987-01-01

    The author discusses his lab's plan for completing the Compact Ignition Tokamak (CIT) conceptual design during calendar year 1987. Around July 1 they froze the subsystem envelopes on the device to continue with the conceptual design. They did this by formalizing a general requirements document. They have been developing the management plan and submitted a version to the DOE July 10. He describes a group of management activities. They released the vacuum vessel Request For Proposals (RFP) on August 5. An RFP to do a major part of the system engineering on the device is being developed. They intend to assemble the device outside of the test cell, then move it into the the test cell, install it there, and bring to the test cell many of the auxiliary facilities from TFTR, for example, power supplies

  4. Compacting spent fuel rods

    International Nuclear Information System (INIS)

    Wachter, W.J.

    1988-01-01

    A method and apparatus for compacting spent fuel rods comprises transferring the rods from a nuclear fuel rod assembly into a different nuclear fuel rod container having a smaller cross section than the assembly. The individual rods are moved from a fuel assembly and through a transition funnel by movable grippers at opposite ends of the funnel. One movable gripper reciprocates between gripping and release positions in a gap between the fuel assembly and the transition funnel. All of the fuel rods are withdrawn concurrently and are merged towards one another into a tighter array within the transition funnel and emerge as a bundle. A movable and a stationary bundle gripper are provided between the funnel and the storage container to advance the bundle of fuel rods into the container. (author)

  5. Compact cryocooler heat exchangers

    International Nuclear Information System (INIS)

    Luna, J.; Frederking, T.H.K.

    1991-01-01

    Compact heat exchangers are subject to different constraints as a room temperature gas is cooled down by a cold stream returning from a JT valve (or a similar cryoprocess component). In particular, the optimization of exchangers for liquid helium systems has to cover a wide range in temperature and density of the fluid. In the present work we address the following thermodynamic questions: 1. The optimization of intermediate temperatures which optimize stage operation (a stage is assumed to have a constant cross section); 2. The optimum temperature difference available for best overall economic performance values. The results are viewed in the context of porous media concepts applied to rather low speeds of fluid flow in narrow passages. In this paper examples of fluid/solid constraints imposed in this non-classical low temperature area are presented

  6. Compact particle accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Elizondo-Decanini, Juan M.

    2017-08-29

    A compact particle accelerator having an input portion configured to receive power to produce particles for acceleration, where the input portion includes a switch, is provided. In a general embodiment, a vacuum tube receives particles produced from the input portion at a first end, and a plurality of wafer stacks are positioned serially along the vacuum tube. Each of the plurality of wafer stacks include a dielectric and metal-oxide pair, wherein each of the plurality of wafer stacks further accelerate the particles in the vacuum tube. A beam shaper coupled to a second end of the vacuum tube shapes the particles accelerated by the plurality of wafer stacks into a beam and an output portion outputs the beam.

  7. Compact vacuum insulation embodiments

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1992-04-28

    An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially point' or line' contacts with the metal wall sheets. In the case of monolithic spacers that form line' contacts, two such spacers with the line contacts running perpendicular to each other form effectively point' contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included. 26 figs.

  8. Compact vacuum insulation

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1993-01-05

    An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially point'' or line'' contacts with the metal wall sheets. In the case of monolithic spacers that form line'' contacts, two such spacers with the line contacts running perpendicular to each other form effectively point'' contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included.

  9. Compact semiconductor lasers

    CERN Document Server

    Yu, Siyuan; Lourtioz, Jean-Michel

    2014-01-01

    This book brings together in a single volume a unique contribution by the top experts around the world in the field of compact semiconductor lasers to provide a comprehensive description and analysis of the current status as well as future directions in the field of micro- and nano-scale semiconductor lasers. It is organized according to the various forms of micro- or nano-laser cavity configurations with each chapter discussing key technical issues, including semiconductor carrier recombination processes and optical gain dynamics, photonic confinement behavior and output coupling mechanisms, carrier transport considerations relevant to the injection process, and emission mode control. Required reading for those working in and researching the area of semiconductors lasers and micro-electronics.

  10. COMPACTION CHARACTERISTICS OF IGUMALE SHALE

    African Journals Online (AJOL)

    *

    In 1933 Proctor first conducted tests on compaction for application to construction of earth fill dams in California. Results published by. Proctor (1933) showed that with a given amount of compaction, there exists for each soil a moisture content, termed the optimum moisture content (OMC) at which a maximum dry density.

  11. Roller-compacted concrete pavements.

    Science.gov (United States)

    2010-09-01

    Roller-compacted concrete (RCC) gets its name from the heavy vibratory steel drum and rubber-tired rollers used to help compact it into its final form. RCC has similar strength properties and consists of the same basic ingredients as conventional con...

  12. An Innovative Adaptive Pushover Procedure Based on Storey Shear

    International Nuclear Information System (INIS)

    Shakeri, Kazem; Shayanfar, Mohsen A.

    2008-01-01

    Since the conventional pushover analyses are unable to consider the effect of the higher modes and progressive variation in dynamic properties, recent years have witnessed the development of some advanced adaptive pushover methods. However in these methods, using the quadratic combination rules to combine the modal forces result in a positive value in load pattern at all storeys and the reversal sign of the modes is removed; consequently these methods do not have a major advantage over their non-adaptive counterparts. Herein an innovative adaptive pushover method based on storey shear is proposed which can take into account the reversal signs in higher modes. In each storey the applied load pattern is derived from the storey shear profile; consequently, the sign of the applied loads in consecutive steps could be changed. Accuracy of the proposed procedure is examined by applying it to a 20-storey steel building. It illustrates a good estimation of the peak response in inelastic phase

  13. A Piezoelectric Shear Stress Sensor

    Science.gov (United States)

    Kim, Taeyang; Saini, Aditya; Kim, Jinwook; Gopalarathnam, Ashok; Zhu, Yong; Palmieri, Frank L.; Wohl, Christopher J.; Jiang, Xiaoning

    2016-01-01

    In this paper, a piezoelectric sensor with a floating element was developed for shear stress measurement. The piezoelectric sensor was designed to detect the pure shear stress suppressing effects of normal stress generated from the vortex lift-up by applying opposite poling vectors to the: piezoelectric elements. The sensor was first calibrated in the lab by applying shear forces and it showed high sensitivity to shear stress (=91.3 +/- 2.1 pC/Pa) due to the high piezoelectric coefficients of PMN-33%PT (d31=-1330 pC/N). The sensor also showed almost no sensitivity to normal stress (less than 1.2 pC/Pa) because of the electromechanical symmetry of the device. The usable frequency range of the sensor is 0-800 Hz. Keywords: Piezoelectric sensor, shear stress, floating element, electromechanical symmetry

  14. Proceedings of the third symposium on the physics and technology of compact toroids in the magnetic fusion energy program

    International Nuclear Information System (INIS)

    Siemon, R.E.

    1981-03-01

    This document contains papers contributed by the participants of the Third Symposium on Physics and Technology of Compact Toroids in the Magnetic Fusion Energy Program. Subjects include reactor aspects of compact toroids, energetic particle rings, spheromak configurations (a mixture of toroidal and poloidal fields), and field-reversed configurations

  15. Compressive Strength of Compacted Clay-Sand Mixes

    Directory of Open Access Journals (Sweden)

    Faseel Suleman Khan

    2014-01-01

    Full Text Available The use of sand to improve the strength of natural clays provides a viable alternative for civil infrastructure construction involving earthwork. The main objective of this note was to investigate the compressive strength of compacted clay-sand mixes. A natural clay of high plasticity was mixed with 20% and 40% sand (SP and their compaction and strength properties were determined. Results indicated that the investigated materials exhibited a brittle behaviour on the dry side of optimum and a ductile behaviour on the wet side of optimum. For each material, the compressive strength increased with an increase in density following a power law function. Conversely, the compressive strength increased with decreasing water content of the material following a similar function. Finally, the compressive strength decreased with an increase in sand content because of increased material heterogeneity and loss of sand grains from the sides during shearing.

  16. Evolution of compact stars and dark dynamical variables

    Energy Technology Data Exchange (ETDEWEB)

    Bhatti, M.Z.; Yousaf, Z. [University of the Punjab, Department of Mathematics, Lahore (Pakistan); Ilyas, M. [University of the Punjab, Centre for High Energy Physics, Lahore (Pakistan)

    2017-10-15

    This work aims to explore the dark dynamical effects of the f(R, T) modified gravity theory on the dynamics of a compact celestial star. We have taken the interior geometry of a spherical star which is filled with an imperfect fluid distribution. The modified field equations are explored by taking a particular form of the f(R, T) model, i.e. f(R, T) = f{sub 1}(R) + f{sub 2}(R)f{sub 3}(T). These equations are utilized to formulate the well-known structure scalars under the dark dynamical effects of this higher-order gravity theory. Also, with the help of these scalar variables, the evolution equations for expansion and shear are formulated. The whole analysis is made under the condition of a constant R and T. We found a crucial significance of dark source terms and dynamical variables on the evolution and density inhomogeneity of compact objects. (orig.)

  17. The insulation irradiation test program for the Compact Ignition Tokamak

    International Nuclear Information System (INIS)

    McManamy, T.J.; Kanemoto, G.; Snook, P.

    1990-01-01

    The electrical insulation for the toroidal field coils of the Compact Ignition Tokamak (CIT) is expected to be exposed to radiation doses on the order of 10 10 rad with ∼90% of the dose from neutrons. The coils are cooled to liquid nitrogen temperature and then heated during the pulse to a peak temperature >300 K. In a program to evaluate the effects of radiation exposure on the insulators, three types of boron-free insulation were irradiated at room temperature in the Advanced Technology Reactor (ATR) and tested at the Idaho National Engineering Laboratory. The materials were Spaulrad-S, Shikishima PG5-1, and Shikishima PG3-1. The first two use a bismaleimide resin and the third an aromatic amine hardened epoxy. Spaulrad-S is a two-dimensional (2-D) weave of S-glass, while the others are 3-D weaves of T-glass. Flexure and shear/compression samples were irradiated to approximately 5 x 10 9 rad and 3 x 10 10 rad with 35 to 40% of the total dose from neutrons. The shear/compression samples were tested in pairs by applying an average compression of 345 MPa and then a shear load. After static tests were completed, fatigue testing was done by cycling the shear load for up to 30,000 cycles with a constant compression. The static shear strength of the samples that did not fail was then determined. Generally, shear strengths on the order of 120 MPa were measured. The behavior of the flexure and shear/compression samples was significantly different; large reductions in the flexure strength were observed, while the shear strength stayed the same or increased slightly. The 3-D weave material demonstrated higher strength and significantly less radiation damage than the 2-D material in flexure but performed nearly identically when tested with combined shear and compression. The epoxy system was much more sensitive to fatigue damage than the bismaleimide materials. 9 refs., 5 figs

  18. Accurate diode behavioral model with reverse recovery

    Science.gov (United States)

    Banáš, Stanislav; Divín, Jan; Dobeš, Josef; Paňko, Václav

    2018-01-01

    This paper deals with the comprehensive behavioral model of p-n junction diode containing reverse recovery effect, applicable to all standard SPICE simulators supporting Verilog-A language. The model has been successfully used in several production designs, which require its full complexity, robustness and set of tuning parameters comparable with standard compact SPICE diode model. The model is like standard compact model scalable with area and temperature and can be used as a stand-alone diode or as a part of more complex device macro-model, e.g. LDMOS, JFET, bipolar transistor. The paper briefly presents the state of the art followed by the chapter describing the model development and achieved solutions. During precise model verification some of them were found non-robust or poorly converging and replaced by more robust solutions, demonstrated in the paper. The measurement results of different technologies and different devices compared with a simulation using the new behavioral model are presented as the model validation. The comparison of model validation in time and frequency domains demonstrates that the implemented reverse recovery effect with correctly extracted parameters improves the model simulation results not only in switching from ON to OFF state, which is often published, but also its impedance/admittance frequency dependency in GHz range. Finally the model parameter extraction and the comparison with SPICE compact models containing reverse recovery effect is presented.

  19. Multi-Scale Investigation of Sheared Flows In Magnetized Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Edward, Jr., Thomas [Auburn Univ., Auburn, AL (United States)

    2014-09-19

    Flows parallel and perpendicular to magnetic fields in a plasma are important phenomena in many areas of plasma science research. The presence of these spatially inhomogeneous flows is often associated with the stability of the plasma. In fusion plasmas, these sheared flows can be stabilizing while in space plasmas, these sheared flows can be destabilizing. Because of this, there is broad interest in understanding the coupling between plasma stability and plasma flows. This research project has engaged in a study of the plasma response to spatially inhomogeneous plasma flows using three different experimental devices: the Auburn Linear Experiment for Instability Studies (ALEXIS) and the Compact Toroidal Hybrid (CTH) stellarator devices at Auburn University, and the Space Plasma Simulation Chamber (SPSC) at the Naval Research Laboratory. This work has shown that there is a commonality of the plasma response to sheared flows across a wide range of plasma parameters and magnetic field geometries. The goal of this multi-device, multi-scale project is to understand how sheared flows established by the same underlying physical mechanisms lead to different plasma responses in fusion, laboratory, and space plasmas.

  20. Compact, self-regulating nuclear power source

    International Nuclear Information System (INIS)

    Peterson, Otis G.; Kimpland, Robert H.

    2008-01-01

    An inherently safe nuclear power source has been designed, that is self-stabilizing and requires no moving mechanical components. Unlike conventional designs, the proposed reactor is self-regulating through the inherent properties of uranium hydride, which serves as a combination fuel and moderator. The temperature driven mobility of the hydrogen contained in the hydride will control the nuclear activity. If the core temperature increases over the set point, the hydrogen is driven out of the core, the moderation drops and the power production decreases. If the temperature drops, the hydrogen returns and the process is reversed. Thus the design is inherently fail-safe and requires only minimal human oversight. The compact nature and inherent safety opens the possibility for low-cost mass production and operation of the reactors. This design has the capability to dramatically alter the manner in which nuclear energy is harnessed for commercial use. (author)

  1. Studying the compactibility of the VT22 high-strength alloy powder obtained by the PREP method

    Science.gov (United States)

    Kryuchkov, D. I.; Berezin, I. M.; Nesterenko, A. V.; Zalazinsky, A. G.; Vichuzhanin, D. I.

    2017-12-01

    Compression curves are plotted for VT22 high-strength alloy powder under conditions of uniaxial compression at room temperature. The density of the compacted briquette at the loading and unloading stages is determined. It is demonstrated that strong interparticle bonds are formed in the area of the action of shear deformation. The results are supposed to be used to identify the flow model of the material studied and to perform the subsequent numerical modeling of the compaction process.

  2. Compact Dexterous Robotic Hand

    Science.gov (United States)

    Lovchik, Christopher Scott (Inventor); Diftler, Myron A. (Inventor)

    2001-01-01

    A compact robotic hand includes a palm housing, a wrist section, and a forearm section. The palm housing supports a plurality of fingers and one or more movable palm members that cooperate with the fingers to grasp and/or release an object. Each flexible finger comprises a plurality of hingedly connected segments, including a proximal segment pivotally connected to the palm housing. The proximal finger segment includes at least one groove defining first and second cam surfaces for engagement with a cable. A plurality of lead screw assemblies each carried by the palm housing are supplied with power from a flexible shaft rotated by an actuator and output linear motion to a cable move a finger. The cable is secured within a respective groove and enables each finger to move between an opened and closed position. A decoupling assembly pivotally connected to a proximal finger segment enables a cable connected thereto to control movement of an intermediate and distal finger segment independent of movement of the proximal finger segment. The dexterous robotic hand closely resembles the function of a human hand yet is light weight and capable of grasping both heavy and light objects with a high degree of precision.

  3. Compact stellarator coils

    International Nuclear Information System (INIS)

    Pomphrey, N.; Berry, L.A.; Boozer, A.H.

    2001-01-01

    Experimental devices to study the physics of high-beta (β>∼4%), low aspect ratio (A<∼4.5) stellarator plasmas require coils that will produce plasmas satisfying a set of physics goals, provide experimental flexibility, and be practical to construct. In the course of designing a flexible coil set for the National Compact Stellarator Experiment, we have made several innovations that may be useful in future stellarator design efforts. These include: the use of Singular Value Decomposition methods for obtaining families of smooth current potentials on distant coil winding surfaces from which low current density solutions may be identified; the use of a Control Matrix Method for identifying which few of the many detailed elements of the stellarator boundary must be targeted if a coil set is to provide fields to control the essential physics of the plasma; the use of Genetic Algorithms for choosing an optimal set of discrete coils from a continuum of potential contours; the evaluation of alternate coil topologies for balancing the tradeoff between physics objective and engineering constraints; the development of a new coil optimization code for designing modular coils, and the identification of a 'natural' basis for describing current sheet distributions. (author)

  4. Compact neutron generator

    Science.gov (United States)

    Leung, Ka-Ngo; Lou, Tak Pui

    2005-03-22

    A compact neutron generator has at its outer circumference a toroidal shaped plasma chamber in which a tritium (or other) plasma is generated. A RF antenna is wrapped around the plasma chamber. A plurality of tritium ion beamlets are extracted through spaced extraction apertures of a plasma electrode on the inner surface of the toroidal plasma chamber and directed inwardly toward the center of neutron generator. The beamlets pass through spaced acceleration and focusing electrodes to a neutron generating target at the center of neutron generator. The target is typically made of titanium tubing. Water is flowed through the tubing for cooling. The beam can be pulsed rapidly to achieve ultrashort neutron bursts. The target may be moved rapidly up and down so that the average power deposited on the surface of the target may be kept at a reasonable level. The neutron generator can produce fast neutrons from a T-T reaction which can be used for luggage and cargo interrogation applications. A luggage or cargo inspection system has a pulsed T-T neutron generator or source at the center, surrounded by associated gamma detectors and other components for identifying explosives or other contraband.

  5. Compact vacuum insulation

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1992-10-27

    Improved compact insulation panel is provided which is comprised of two adjacent metal sheets spaced close together with a plurality of spherical, or other discretely shaped, glass or ceramic beads optimally positioned between the sheets to provide support and maintain the spacing between the metal sheets when the gases there between are evacuated to form a vacuum. These spherical glass beads provide the maximum support while minimizing thermal conductance. In its preferred embodiment; these two metal sheets are textured with ribs or concave protrusions in conjunction with the glass beads to maximize the structural integrity of the panels while increasing the spacing between beads, thereby reducing the number of beads and the number of thermal conduction paths. Glass or porcelain-enameled liners in combination with the glass spacers and metal sidewalls effectively decrease thermal conductivity, and various laminates, including wood, porcelain-enameled metal, and others effectively increase the strength and insulation capabilities of the panels. Also, a metal web is provided to hold the spacers in place, and strategic grooves are shown to accommodate expansion and contraction or shaping of the panels. 35 figs.

  6. Chemically induced compaction bands in geomaterials

    Science.gov (United States)

    Stefanou, Ioannis; Sulem, Jean

    2013-04-01

    -sensitive Dilatant Materials." Journal of the Mechanics and Physics of Solids 23.6 (1975): 371-394. [2] I. Vardoulakis and J. Sulem: Bifurcation analysis in geomechanics. Blackie. 1995. [3] J.W. Rudnicki, "Conditions for Compaction and Shear Bands in a Transversely Isotropic Material." International Journal of Solids and Structures 39.13-14 (2002): 3741-3756. [4] L.-B. Hu and T. Hueckel. "Coupled Chemo-mechanics of Intergranular Contact: Toward a Three-scale Model." Computers and Geotechnics 34.4 (2007): 306-327. [5] R. Nova, R. Castellanza, and C. Tamagnini. "A Constitutive Model for Bonded Geomaterials Subject to Mechanical And/or Chemical Degradation." International Journal for Numerical and Analytical Methods in Geomechanics 27.9 (2003): 705-732. [6] J.D. Rimstidt and H.L. Barnes. "The Kinetics of Silica-water Reactions." Geochimica et Cosmochimica Acta 44.11 (1980): 1683-1699. [7] P.V. Lade, J.A. Yamamuro and P.A. Bopp "Significance of Particle Crushing in Granular Materials." Journal of Geotechnical Engineering, 122.4 (1996): 309-316.

  7. Shear Thickening Electrolyte Built from Sterically Stabilized Colloidal Particles.

    Science.gov (United States)

    Shen, Brian H; Armstrong, Beth L; Doucet, Mathieu; Heroux, Luke; Browning, James F; Agamalian, Michael; Tenhaeff, Wyatt E; Veith, Gabriel M

    2018-03-21

    We present a method to prepare shear thickening electrolytes consisting of silica nanoparticles in conventional liquid electrolytes with limited flocculation. These electrolytes rapidly and reversibly stiffen to solidlike behaviors in the presence of external shear or high impact, which is promising for improved lithium ion battery safety, especially in electric vehicles. However, in initial chemistries the silica nanoparticles aggregate and/or sediment in solution over time. Here, we demonstrate steric stabilization of silica colloids in conventional liquid electrolyte via surface-tethered PMMA brushes, synthesized via surface-initiated atom transfer radical polymerization. The PMMA increases the magnitude of the shear thickening response, compared to the uncoated particles, from 0.311 to 2.25 Pa s. Ultrasmall-angle neutron scattering revealed a reduction in aggregation of PMMA-coated silica nanoparticles compared to bare silica nanoparticles in solution under shear and at rest, suggesting good stabilization. Conductivity tests of shear thickening electrolytes (30 wt % solids in electrolyte) at rest were performed with interdigitated electrodes positioned near the meniscus of electrolytes over the course of 24 h to track supernatant formation. Conductivity of electrolytes with bare silica increased from 10.1 to 11.6 mS cm -1 over 24 h due to flocculation. In contrast, conductivity of electrolytes with PMMA-coated silica remained stable at 6.1 mS cm -1 over the same time period, suggesting good colloid stability.

  8. Improving Interlaminar Shear Strength

    Science.gov (United States)

    Jackson, Justin

    2015-01-01

    To achieve NASA's mission of space exploration, innovative manufacturing processes are being applied to the fabrication of complex propulsion elements.1 Use of fiber-reinforced, polymeric composite tanks are known to reduce weight while increasing performance of propulsion vehicles. Maximizing the performance of these materials is needed to reduce the hardware weight to result in increased performance in support of NASA's missions. NASA has partnered with the Mississippi State University (MSU) to utilize a unique scalable approach of locally improving the critical properties needed for composite structures. MSU is responsible for the primary development of the concept with material and engineering support provided by NASA. The all-composite tank shown in figure 1 is fabricated using a prepreg system of IM7 carbon fiber/CYCOM 5320-1 epoxy resin. This is a resin system developed for out-of-autoclave applications. This new technology is needed to support the fabrication of large, all composite structures and is currently being evaluated on a joint project with Boeing for the Space Launch System (SLS) program. In initial efforts to form an all composite pressure vessel using this prepreg system, a 60% decrease in properties was observed in scarf joint regions. Inspection of these areas identified interlaminar failure in the adjacent laminated structure as the main failure mechanism. This project seeks to improve the interlaminar shear strength (ILSS) within the prepreg layup by locally modifying the interply region shown in figure 2.2

  9. Impact of shear rate modulation on vascular function in humans.

    Science.gov (United States)

    Tinken, Toni M; Thijssen, Dick H J; Hopkins, Nicola; Black, Mark A; Dawson, Ellen A; Minson, Christopher T; Newcomer, Sean C; Laughlin, M Harold; Cable, N Timothy; Green, Daniel J

    2009-08-01

    Shear stress is an important stimulus to arterial adaptation in response to exercise and training in humans. We recently observed significant reverse arterial flow and shear during exercise and different antegrade/retrograde patterns of shear and flow in response to different types of exercise. The purpose of this study was to simultaneously examine flow-mediated dilation, a largely NO-mediated vasodilator response, in both brachial arteries of healthy young men before and after 30-minute interventions consisting of bilateral forearm heating, recumbent leg cycling, and bilateral handgrip exercise. During each intervention, a cuff inflated to 60 mm Hg was placed on 1 arm to unilaterally manipulate the shear rate stimulus. In the noncuffed arm, antegrade flow and shear increased similarly in response to each intervention (ANOVA; P<0.001, no interaction between interventions; P=0.71). Baseline flow-mediated dilation (4.6%, 6.9%, and 6.7%) increased similarly in response to heating, handgrip, and cycling (8.1%, 10.4%, and 8.9%, ANOVA; P<0.001, no interaction; P=0.89). In contrast, cuffed arm antegrade shear rate was lower than in the noncuffed arm for all of the conditions (P<0.05), and the increase in flow-mediated dilation was abolished in this arm (4.7%, 6.7%, and 6.1%; 2-way ANOVA: all conditions interacted P<0.05). These results suggest that differences in the magnitude of antegrade shear rate transduce differences in endothelial vasodilator function in humans, a finding that may have relevance for the impact of different exercise interventions on vascular adaptation in humans.

  10. Good environmental performance from Compact

    International Nuclear Information System (INIS)

    Kinnunen, L.

    1996-01-01

    For Rovaniemi and the designers of the town's new Suosiola power plant, it was clear from the start that it would be based on atmospheric-pressurized fluidized bed technology. In a bid to keep environmental emissions to a minimum, the decision fell to Foster Wheeler's new Compact CFB boiler. Work on developing the Compact boiler has been carried out since 1989. Flow models and cold air and hot air tests were completed in 1990. The first Compact boiler, an 18 MW unit, was commissioned at Kuhmo in 1993; this was followed by one at Kokkola in 1994

  11. The United Nations Global Compact

    DEFF Research Database (Denmark)

    Rasche, Andreas; Waddock, Sandra; McIntosh, Malcolm

    2013-01-01

    This article reviews the interdisciplinary literature on the UN Global Compact. The review identifies three research perspectives, which scholars have used to study the UN Global Compact so far: a historical perspective discussing the Global Compact in the context of UN-business relations......, an operational perspective discussing the composition and impact of its participants, as well as a governance perspective discussing the constraints and opportunities of the initiative as an institutionalized arena for addressing global governance gaps. The authors contrast these three perspectives and identify...

  12. Fifty years of shear zones

    Science.gov (United States)

    Graham, Rodney

    2017-04-01

    We are here, of course, because 1967 saw the publication of John Ramsay's famous book. Two years later a memorable field trip from Imperial College to the Outer Hebrides saw John on a bleak headland on the coast of North Uist where a relatively undeformed metadolerite within Lewisian (Precambrian) gneisses contained ductile shear zones with metamorphic fabrics in amphibolite facies. One particular outcrop was very special - a shear zone cutting otherwise completely isotropic, undeformed metadolerite, with an incremental foliation starting to develop at 45° to the deformation zone, and increasing in intensity as it approached the shear direction. Here was proof of the process of simple shear under ductile metamorphic conditions - the principles of simple shear outlined in John Ramsay's 1967 book clearly visible in nature, and verified by Ramsay's mathematical proofs in the eventual paper (Ramsay and Graham, 1970). Later work on the Lewisian on the mainland of Scotland, in South Harris, in Africa, and elsewhere applied Ramsay's simple shear principles more liberally, more imprecisely and on larger scale than at Caisteal Odair, but in retrospect it documented what seems now to be the generality of mid and lower crustal deformation. Deep seismic reflection data show us that on passive margins hyper-stretched continental crust (whether or not cloaked by Seaward Dipping Reflectors) seems to have collapsed onto the mantle. Crustal faults mostly sole out at or above the mantle - so the Moho is a detachment- an 'outer marginal detachment', if you like, and, of course, it must be a ductile shear. On non-volcanic margins this shear zone forms the first formed ocean floor before true sea floor spreading gets going to create real oceanic crust. Gianreto Manatschal, Marcel Lemoine and others realised that the serpentinites described in parts of the Alps are exposed remnants of this ductile shear zone. Associated ophicalcite breccias tell of sea floor exposure, while high

  13. COMPACTNESS IN INTUITIONISTIC FUZZY MULTISET TOPOLOGY

    OpenAIRE

    Kunnambath, Shinoj Thekke; John, Sunil Jacob

    2017-01-01

    – In this paper, we discussVarious properties of Compact and Homeomorphic Intuitionistic Fuzzy Multiset Topological spacesarious properties of Compact and Homeomorphic Intuitionistic Fuzzy Multiset Topological spaces

  14. Analytical and Numerical Analysis of the Acoustics of Shallow Flow Reversal Chambers

    OpenAIRE

    Qazizadeh, Alireza

    2012-01-01

    Flow reversal chambers are mainly used to accomplish a compact silencer design needed on a vehicle. Generally in this configuration the inlet and outlet ports are on the same face and the flow direction is reversed. During many years different authors have tried to develop 1D and 3D models for evaluating the acoustic performance of circular and rectangular reversing chambers. Ih [1] categorizes four methods for evaluating the acoustic performance of the reversing chamber. The first involves u...

  15. Parametric Study of Rockbolt Shear Behaviour by Double Shear Test

    Science.gov (United States)

    Li, L.; Hagan, P. C.; Saydam, S.; Hebblewhite, B.; Li, Y.

    2016-12-01

    Failure of rockbolts as a result of shear or bending loads can often be found in underground excavations. The response of rock anchorage systems has been studied in shear, both by laboratory tests as well as numerical modelling in this study. A double shear test was developed to examine the shear behaviour of a bolt installed across two joints at different angles. To investigate the influence of various parameters in the double shear test, a numerical model of a fully grouted rockbolt installed in concrete was constructed and analysed using FLAC3D code. A number of parameters were considered including concrete strength, inclination between rockbolt and joints and rockbolt diameter. The numerical model considered three material types (steel, grout and concrete) and three interfaces (concrete-concrete, grout-concrete and grout-rockbolt). The main conclusions drawn from the study were that the level of bolt resistance to shear was influenced by rock strength, inclination angle, and diameter of the rockbolt. The numerical simulation of the bolt/grout interaction and deformational behaviour was found to be in close agreement with earlier experimental test results.

  16. Compact instantaneous water heater

    Energy Technology Data Exchange (ETDEWEB)

    Azevedo, Jorge G.W.; Machado, Antonio R.; Ferraz, Andre D.; Rocha, Ivan C.C. da; Konishi, Ricardo [Companhia de Gas de Santa Catarina (SCGAS), Florianopolis, SC (Brazil); Lehmkuhl, Willian A.; Francisco Jr, Roberto W.; Hatanaka, Ricardo L.; Pereira, Fernando M.; Oliveira, Amir A.M. [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil)

    2012-07-01

    This paper presents an experimental study of combustion in an inert porous medium in a liquid heating device application. This project aims to increase efficiency in the application of natural gas in residential and commercial sectors with the use of advanced combustion and heat transfer. The goal is to facilitate the development of a high performance compact water heater allowing hot water supply for up to two simultaneous showers. The experiment consists in a cylindrical porous burner with an integrated annular water heat exchanger. The reactants were injected radially into the burner and the flame stabilizes within the porous matrix. The water circulates in a coiled pipe positioned at the center of the burner. This configuration allows for heat transfer by conduction and radiation from the solid matrix to the heat exchanger. This article presented preliminary experimental results of a new water heater based on an annular porous burner. The range of equivalence ratios tested varied from 0.65 to 0.8. The power range was varied from 3 to 5 kW. Increasing the equivalence ratio or decreasing the total power input of the burner resulted in increased thermal efficiencies of the water heater. Thermal efficiencies varying from 60 to 92% were obtained. The condition for the goal of a comfortable bath was 20 deg C for 8-12 L/min. This preliminary prototype has achieved water temperature of 11deg C for 5 L/min. Further optimizations will be necessary in order to achieve intense heating with high thermal efficiency. (author)

  17. What Is Business's Social Compact?

    Science.gov (United States)

    Avishai, Bernard

    1994-01-01

    Under the "new" social compact, businesses must focus on continuous learning and thus have both an obligation to support teaching and an opportunity to profit from it. Learning organizations must also be teaching organizations. (SK)

  18. Compact, Ultrasensitive Formaldehyde Monitor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Small Business Innovative Research Phase II proposal seeks to develop a compact UV laser ?based sensor for Earth science and planetary atmosphere exploration....

  19. Experimental and theoretical studies on concrete structures with special-shaped shear walls

    Directory of Open Access Journals (Sweden)

    LIU Jianxin

    2014-06-01

    Full Text Available On the basis of concept design and staggered shear panels structure,this paper puts forward a new reinforced concrete high rise biuding structure with special-shaped shear walls and presents an experimental study of the seismic performance of the new special-shaped shear walls structure under low reversed cyclic loading using MTS electro hydraulic servo system.Compared with experimental results,a finite element analysis on this special-shaped shear wall structure,which considers the nonlinearity of concrete structure,is found suitable.It shows that the experimental results fairly confirms to the calculated values,which indicates that this new structure has advantages as good architecture function,big effective space,high overall lateral stiffness,fine ductility,advanced seismic behavior,etc..That is,the close r agreement between the theoretical and experimental results indicates the proposed shear wall structure has wide applications.

  20. SEDflume - High Shear Stress Flume

    Data.gov (United States)

    Federal Laboratory Consortium — The U.S. Army Corps of Engineers High Shear Stress flume (SEDflume) is designed for estimating erosion rates of fine-grained and mixed fine/coarse grained sediments...

  1. Compaction with Automatic Jog Introduction

    Science.gov (United States)

    1986-11-01

    conserve area. For these reasons, compaction algorithms have gained widespread attention in the VLSI literature S ,[4, 5, 9, 111, and have been incorporated...graph is (V,E), then Dijkstra’s algorithm runs in time 6 (IEl - IVI log IV!) using Fibonacci heaps [3]. In contrast, the longest- path algorithm of...however, so that hierarchical compaction can alleviate much of the resource -. 33 pa. .1 N’, problem. It also may be suited to use in channel routing

  2. Shear Alfven waves in tokamaks

    International Nuclear Information System (INIS)

    Kieras, C.E.

    1982-12-01

    Shear Alfven waves in an axisymmetric tokamak are examined within the framework of the linearized ideal MHD equations. Properties of the shear Alfven continuous spectrum are studied both analytically and numerically. Implications of these results in regards to low frequency rf heating of toroidally confined plasmas are discussed. The structure of the spatial singularities associated with these waves is determined. A reduced set of ideal MHD equations is derived to describe these waves in a very low beta plasma

  3. Shear properties and permeability of the joint of bentonite buffer for geological disposal of high-level radioactive waste

    International Nuclear Information System (INIS)

    Imamura, Masahiro; Chijimatsu, Masakazu; Amemiya, Kiyoshi; Sugita, Yutaka; Kikuchi, Hirohito; Murata, Sumihiko; Saito, Toshiaki

    2001-01-01

    In order to understand the shear and hydraulic properties of the joint of bentonite buffer for geological disposal of high level radioactive waste, single plane shear tests and permeability tests were conducted. Two types of bentonite specimens, compressed in the laboratory and compacted at the test site in Kamaishi Mine, were prepared considering construction methods. From these tests, the joint part of the bentonite buffer is the weakest and the most permeable part. However, its influence on shear strength and permeability decreases, after the bentonite buffer is saturated and the effect of swelling is appeared. (author)

  4. Shear viscosity of an ordering latex suspension

    NARCIS (Netherlands)

    van der Vorst, A.M.; van der Vorst, B.; van den Ende, Henricus T.M.; Aelmans, N.J.J.; Mellema, J.

    1997-01-01

    The shear viscosity of a latex which is ordered at rest is studied as a function of the shear rate and volume fraction. At low shear rates and for moderate to high volume fractions, the flow curves show dynamic yield behavior which disappears below a volume fraction of 8%. At high shear rates, the

  5. Experimental observation of shear thickening oscillation

    DEFF Research Database (Denmark)

    Nagahiro, Shin-ichiro; Nakanishi, Hiizu; Mitarai, Namiko

    2013-01-01

    We report experimental observations of the shear thickening oscillation, i.e. the spontaneous macroscopic oscillation in the shear flow of severe shear thickening fluid. Using a density-matched starch-water mixture, in the cylindrical shear flow of a few centimeters flow width, we observed...

  6. Localization and instability in sheared granular materials: Role of friction and vibration

    Science.gov (United States)

    Kothari, Konik R.; Elbanna, Ahmed E.

    2017-02-01

    Shear banding and stick-slip instabilities have been long observed in sheared granular materials. Yet, their microscopic underpinnings, interdependencies, and variability under different loading conditions have not been fully explored. Here we use a nonequilibrium thermodynamics model, the Shear Transformation Zone theory, to investigate the dynamics of strain localization and its connection to stability of sliding in sheared, dry, granular materials. We consider frictional and frictionless grains as well as the presence and absence of acoustic vibrations. Our results suggest that at low and intermediate strain rates, persistent shear bands develop only in the absence of vibrations. Vibrations tend to fluidize the granular network and delocalize slip at these rates. Stick-slip is observed only for frictional grains, and it is confined to the shear band. At high strain rates, stick-slip disappears and the different systems exhibit similar stress-slip response. Changing the vibration intensity, duration or time of application alters the system response and may cause long-lasting rheological changes. We analyze these observations in terms of possible transitions between rate strengthening and rate weakening response facilitated by a competition between shear-induced dilation and vibration-induced compaction. We discuss the implications of our results on dynamic triggering, quiescence, and strength evolution in gouge-filled fault zones.

  7. Compact Intracloud Discharges

    Energy Technology Data Exchange (ETDEWEB)

    Smith, David A. [Univ. of Colorado, Boulder, CO (United States)

    1998-11-01

    In November of 1993, mysterious signals recorded by a satellite-borne broadband VHF radio science experiment called Blackboard led to a completely unexpected discovery. Prior to launch of the ALEXIS satellite, it was thought that its secondary payload, Blackboard, would most often detect the radio emissions from lightning when its receiver was not overwhelmed by noise from narrowband communication carriers. Instead, the vast majority of events that triggered the instrument were isolated pairs of pulses that were one hundred times more energetic than normal thunderstorm electrical emissions. The events, which came to be known as TIPPs (for transionospheric pulse pairs), presented a true mystery to the geophysics community. At the time, it was not even known whether the events had natural or anthropogenic origins. After two and one half years of research into the unique signals, two ground-based receiver arrays in New Mexico first began to detect and record thunderstorm radio emissions that were consistent with the Blackboard observations. On two occasions, the ground-based systems and Blackboard even recorded emissions that were produced by the same exact events. From the ground based observations, it has been determined that TIPP events areproduced by brief, singular, isolated, intracloud electrical discharges that occur in intense regions of thunderstorms. These discharges have been dubbed CIDS, an acronym for compact intracloud discharges. During the summer of 1996, ground-based receiver arrays were used to record the electric field change signals and broadband HF emissions from hundreds of CIDS. Event timing that was accurate to within a few microseconds made possible the determination of source locations using methods of differential time of arrival. Ionospheric reflections of signals were recorded in addition to groundwave/line-of-sight signals and were used to determine accurate altitudes for the discharges. Twenty-four CIDS were recorded from three

  8. The Effects of Shear Strain, Fabric, and Porosity Evolution on Elastic and Mechanical Properties of Clay-Rich Fault Gouge

    Science.gov (United States)

    Kenigsberg, A.; Saffer, D. M.; Riviere, J.; Marone, C.

    2017-12-01

    Vp at shear strains of 7-9 reflects near complete alignment and increased compaction and density. This interpretation is supported by SEM imaging and analysis of a suite of experiments stopped at different shear strains.

  9. Managing Reverse Logistics or Reversing Logistics Management?

    NARCIS (Netherlands)

    M.P. de Brito (Marisa)

    2004-01-01

    textabstractIn the past, supply chains were busy fine-tuning the logistics from raw material to the end customer. Today an increasing flow of products is going back in the chain. Thus, companies have to manage reverse logistics as well.This thesis contributes to a better understanding of reverse

  10. Co-compact Gabor Systems on Locally Compact Abelian Groups

    DEFF Research Database (Denmark)

    Jakobsen, Mads Sielemann; Lemvig, Jakob

    2016-01-01

    In this work we extend classical structure and duality results in Gabor analysis on the euclidean space to the setting of second countable locally compact abelian (LCA) groups. We formulate the concept of rationally oversampling of Gabor systems in an LCA group and prove corresponding characteriz......In this work we extend classical structure and duality results in Gabor analysis on the euclidean space to the setting of second countable locally compact abelian (LCA) groups. We formulate the concept of rationally oversampling of Gabor systems in an LCA group and prove corresponding...

  11. Focusing of Shear Shock Waves

    Science.gov (United States)

    Giammarinaro, Bruno; Espíndola, David; Coulouvrat, François; Pinton, Gianmarco

    2018-01-01

    Focusing is a ubiquitous way to transform waves. Recently, a new type of shock wave has been observed experimentally with high-frame-rate ultrasound: shear shock waves in soft solids. These strongly nonlinear waves are characterized by a high Mach number, because the shear wave velocity is much slower, by 3 orders of magnitude, than the longitudinal wave velocity. Furthermore, these waves have a unique cubic nonlinearity which generates only odd harmonics. Unlike longitudinal waves for which only compressional shocks are possible, shear waves exhibit cubic nonlinearities which can generate positive and negative shocks. Here we present the experimental observation of shear shock wave focusing, generated by the vertical motion of a solid cylinder section embedded in a soft gelatin-graphite phantom to induce linearly vertically polarized motion. Raw ultrasound data from high-frame-rate (7692 images per second) acquisitions in combination with algorithms that are tuned to detect small displacements (approximately 1 μ m ) are used to generate quantitative movies of gel motion. The features of shear shock wave focusing are analyzed by comparing experimental observations with numerical simulations of a retarded-time elastodynamic equation with cubic nonlinearities and empirical attenuation laws for soft solids.

  12. Statistical mechanics of vibration-induced compaction of powders

    Science.gov (United States)

    Edwards, S. F.; Grinev, D. V.

    1998-10-01

    We propose a theory that describes the density relaxation of loosely packed, cohesionless granular material under mechanical tapping. Using the compactivity concept, we develop a formalism of statistical mechanics that allows us to calculate the density of a powder as a function of time and compactivity. A simple fluctuation-dissipation relation that relates compactivity to the amplitude and frequency of a tapping is proposed. The experimental data of Nowak et al. [Powder Technol. 94, 79 (1997)] show how the density of powder initially deposited in a fluffy state evolves under carefully controlled tapping towards a random close packing (RCP) density. Ramping the vibration amplitude repeatedly up and back down again reveals the existence of reversible and irreversible branches in the response. In the framework of our approach the reversible branch (along which the RCP density is obtained) corresponds to the steady-state solution of the Fokker-Planck equation, whereas the irreversible one is represented by a superposition of ``excited state'' eigenfunctions. These two regimes of response are analyzed theoretically and a qualitative explanation of the hysteresis curve is offered.

  13. HIV-1 reverse transcription.

    Science.gov (United States)

    Hu, Wei-Shau; Hughes, Stephen H

    2012-10-01

    Reverse transcription and integration are the defining features of the Retroviridae; the common name "retrovirus" derives from the fact that these viruses use a virally encoded enzyme, reverse transcriptase (RT), to convert their RNA genomes into DNA. Reverse transcription is an essential step in retroviral replication. This article presents an overview of reverse transcription, briefly describes the structure and function of RT, provides an introduction to some of the cellular and viral factors that can affect reverse transcription, and discusses fidelity and recombination, two processes in which reverse transcription plays an important role. In keeping with the theme of the collection, the emphasis is on HIV-1 and HIV-1 RT.

  14. Bed-parallel compaction bands in aeolian sandstone: Their identification, characterization and implications

    Science.gov (United States)

    Aydin, Atilla; Ahmadov, Ramil

    2009-12-01

    This study combines field observations and laboratory analyses to identify and characterize predominantly bed-parallel compaction bands in the aeolian Aztec Sandstone exposed in the Valley of Fire State Park, Nevada. These bed-parallel compaction bands display morphological and geometrical characteristics of deformation bands of various modes previously described in the literature, such as positive relief, echelon geometry, "bridge" and "eye" structure, and zonal occurrence. Portions of some bands cross-cut sedimentary layers, thereby distinguishing themselves from depositional bedding. Laboratory image analyses of several samples collected from bed-parallel bands, using a computational rock physics algorithm, show that their porosities are less than half that of the host rock and their permeability is nearly one order of magnitude less. In addition, the study area includes compaction bands that have dip angles ranging from sub-horizontal to greater than 20°. Parts of these bands have even higher dip angles and show evidence for increasing intragranular fracturing and shearing as the band inclination increases. We attribute this variation to shear-enhanced compaction, a mechanism proposed earlier by experimental rock mechanists. One of the implications of the occurrence of localized compaction in the form of discrete bands parallel to flat-lying and low-angle bedding is that it provides an alternative or an additional mode to a vertically continuous compaction in loose or poorly cemented sediments. If pervasive, bed-parallel compaction bands with significantly lower porosity than that of the surrounding undeformed rock should result in a significant heterogeneity and vertical anisotropy in seismic velocities and hydraulic properties of granular rocks.

  15. Squirming through shear thinning fluids

    Science.gov (United States)

    Datt, Charu; Zhu, Lailai; Elfring, Gwynn J.; Pak, On Shun

    2015-11-01

    Many microorganisms find themselves surrounded by fluids which are non-Newtonian in nature; human spermatozoa in female reproductive tract and motile bacteria in mucosa of animals are common examples. These biological fluids can display shear-thinning rheology whose effects on the locomotion of microorganisms remain largely unexplored. Here we study the self-propulsion of a squirmer in shear-thinning fluids described by the Carreau-Yasuda model. The squirmer undergoes surface distortions and utilizes apparent slip-velocities around its surface to swim through a fluid medium. In this talk, we will discuss how the nonlinear rheological properties of a shear-thinning fluid affect the propulsion of a swimmer compared with swimming in Newtonian fluids.

  16. Shear Brillouin light scattering microscope.

    Science.gov (United States)

    Kim, Moonseok; Besner, Sebastien; Ramier, Antoine; Kwok, Sheldon J J; An, Jeesoo; Scarcelli, Giuliano; Yun, Seok Hyun

    2016-01-11

    Brillouin spectroscopy has been used to characterize shear acoustic phonons in materials. However, conventional instruments had slow acquisition times over 10 min per 1 mW of input optical power, and they required two objective lenses to form a 90° scattering geometry necessary for polarization coupling by shear phonons. Here, we demonstrate a confocal Brillouin microscope capable of detecting both shear and longitudinal phonons with improved speeds and with a single objective lens. Brillouin scattering spectra were measured from polycarbonate, fused quartz, and borosilicate in 1-10 s at an optical power level of 10 mW. The elastic constants, phonon mean free path and the ratio of the Pockels coefficients were determined at microscopic resolution.

  17. SHEAR ACCELERATION IN EXPANDING FLOWS

    Energy Technology Data Exchange (ETDEWEB)

    Rieger, F. M. [ZAH, Institut für Theoretische Astrophysik, Universität Heidelberg, Philosophenweg 12, D-69120 Heidelberg (Germany); Duffy, P., E-mail: frank.rieger@mpi-hd.mpg.de, E-mail: peter.duffy@ucd.ie [University College Dublin, Belfield, Dublin 4 (Ireland)

    2016-12-10

    Shear flows are naturally expected to occur in astrophysical environments and potential sites of continuous non-thermal Fermi-type particle acceleration. Here we investigate the efficiency of expanding relativistic outflows to facilitate the acceleration of energetic charged particles to higher energies. To this end, the gradual shear acceleration coefficient is derived based on an analytical treatment. The results are applied to the context of the relativistic jets from active galactic nuclei. The inferred acceleration timescale is investigated for a variety of conical flow profiles (i.e., power law, Gaussian, Fermi–Dirac) and compared to the relevant radiative and non-radiative loss timescales. The results exemplify that relativistic shear flows are capable of boosting cosmic-rays to extreme energies. Efficient electron acceleration, on the other hand, requires weak magnetic fields and may thus be accompanied by a delayed onset of particle energization and affect the overall jet appearance (e.g., core, ridge line, and limb-brightening).

  18. Compact Chern–Simons vortices

    Directory of Open Access Journals (Sweden)

    D. Bazeia

    2017-09-01

    Full Text Available We introduce and investigate new models of the Chern–Simons type in the three-dimensional spacetime, focusing on the existence of compact vortices. The models are controlled by potentials driven by a single real parameter that can be used to change the profile of the vortex solutions as they approach their boundary values. One of the models unveils an interesting new behavior, the tendency to make the vortex compact, as the parameter increases to larger and larger values. We also investigate the behavior of the energy density and calculate the total energy numerically.

  19. Professional Windows Embedded Compact 7

    CERN Document Server

    Phung, Samuel; Joubert, Thierry; Hall, Mike

    2011-01-01

    Learn to program an array of customized devices and solutions As a compact, highly efficient, scalable operating system, Windows Embedded Compact 7 (WEC7) is one of the best options for developing a new generation of network-enabled, media-rich, and service-oriented devices. This in-depth resource takes you through the benefits and capabilities of WEC7 so that you can start using this performance development platform today. Divided into several major sections, the book begins with an introduction and then moves on to coverage of OS design, application development, advanced application developm

  20. Modeling of compact loop antennas

    International Nuclear Information System (INIS)

    Baity, F.W.

    1987-01-01

    A general compact loop antenna model which treats all elements of the antenna as lossy transmission lines has been developed. In addition to capacitively-tuned resonant double loop (RDL) antennas the model treats stub-tuned resonant double loop antennas. Calculations using the model have been compared with measurements on full-scale mockups of resonant double loop antennas for ATF and TFTR in order to refine the transmission line parameters. Results from the model are presented for RDL antenna designs for ATF, TFTR, Tore Supra, and for the Compact Ignition Tokamak

  1. Isometric coactions of compact quantum groups on compact ...

    Indian Academy of Sciences (India)

    a compact quantum metric space in the framework of Rieffel, where the metric structure is given by a ... For finite classical metric spaces, this problem was studied by Banica [2]. He has given a definition for a quantum symmetry of a classical finite metric space. With this ..... The graph theory we need concerns flow networks.

  2. Shear rheology of extended nanoparticles

    Science.gov (United States)

    Petersen, Matt K.; Lane, J. Matthew D.; Grest, Gary S.

    2010-07-01

    Nonequilibrium molecular-dynamics simulations are presented for the shear rheology of suspensions of extended “jack”-shaped nanoparticles in an explicit solvent. The shear viscosity is measured for two jack-shaped nanoparticle suspensions for volume fractions from 0.01 to 0.15 and compared to spherical nanoparticles of the same mass. Large differences, in some cases, orders of magnitude, are observed for both the equilibrium viscosity and diffusion constant as the shape of the nanoparticle is varied. The source of enhanced viscosity is the very large effective volume swept out by these extended nanoparticles which allows them to become highly entangled even at low volume fraction.

  3. Shear strength of non-shear reinforced concrete elements

    DEFF Research Database (Denmark)

    Hoang, Cao linh

    1997-01-01

    . The position of the crack in which sliding takes place is determined by the crack sliding model developed by Jin-Ping Zhang. The theoretical calculations are compared with test results reported in the literature. A good agreement has been found.A simplified method to calculate the shear capacity of T...

  4. Compaction dynamics of crunchy granular material

    Directory of Open Access Journals (Sweden)

    Guillard François

    2017-01-01

    Full Text Available Compaction of brittle porous material leads to a wide variety of densification patterns. Static compaction bands occurs naturally in rocks or bones, and have important consequences in industry for the manufacturing of powder tablets or metallic foams for example. Recently, oscillatory compaction bands have been observed in brittle porous media like snow or cereals. We will discuss the great variety of densification patterns arising during the compaction of puffed rice, including erratic compaction at low velocity, one or several travelling compaction bands at medium velocity and homogeneous compaction at larger velocity. The conditions of existence of each pattern are studied thanks to a numerical spring lattice model undergoing breakage and is mapped to the phase diagram of the patterns based on dimensionless characteristic quantities. This also allows to rationalise the evolution of the compaction behaviour during a single test. Finally, the localisation of compaction bands is linked to the strain rate sensitivity of the material.

  5. Compaction dynamics of crunchy granular material

    Science.gov (United States)

    Guillard, François; Golshan, Pouya; Shen, Luming; Valdès, Julio R.; Einav, Itai

    2017-06-01

    Compaction of brittle porous material leads to a wide variety of densification patterns. Static compaction bands occurs naturally in rocks or bones, and have important consequences in industry for the manufacturing of powder tablets or metallic foams for example. Recently, oscillatory compaction bands have been observed in brittle porous media like snow or cereals. We will discuss the great variety of densification patterns arising during the compaction of puffed rice, including erratic compaction at low velocity, one or several travelling compaction bands at medium velocity and homogeneous compaction at larger velocity. The conditions of existence of each pattern are studied thanks to a numerical spring lattice model undergoing breakage and is mapped to the phase diagram of the patterns based on dimensionless characteristic quantities. This also allows to rationalise the evolution of the compaction behaviour during a single test. Finally, the localisation of compaction bands is linked to the strain rate sensitivity of the material.

  6. Reverse logistics - a framework

    OpenAIRE

    de Brito, M.P.; Dekker, R.

    2002-01-01

    textabstractIn this paper we define and compare Reverse Logistics definitions. We start by giving an understanding framework of Reverse Logistics: the why-what-how. By this means, we put in context the driving forces for Reverse Logistics, a typology of return reasons, a classification of products, processes and actors. In addition we provide a decision framework for Reverse Logistics and we present it according to long, medium and short term decisions, i.e. strategic-tactic-operational decis...

  7. HIV-1 Reverse Transcription

    OpenAIRE

    Hu, Wei-Shau; Hughes, Stephen H.

    2012-01-01

    Reverse transcription and integration are the defining features of the Retroviridae; the common name “retrovirus” derives from the fact that these viruses use a virally encoded enzyme, reverse transcriptase (RT), to convert their RNA genomes into DNA. Reverse transcription is an essential step in retroviral replication. This article presents an overview of reverse transcription, briefly describes the structure and function of RT, provides an introduction to some of the cellular and viral fact...

  8. Reverse logistics - a framework

    NARCIS (Netherlands)

    M.P. de Brito (Marisa); R. Dekker (Rommert)

    2002-01-01

    textabstractIn this paper we define and compare Reverse Logistics definitions. We start by giving an understanding framework of Reverse Logistics: the why-what-how. By this means, we put in context the driving forces for Reverse Logistics, a typology of return reasons, a classification of

  9. The classification of 2-compact groups

    OpenAIRE

    Andersen, Kasper K. S.; Grodal, Jesper

    2006-01-01

    We prove that any connected 2-compact group is classified by its 2-adic root datum, and in particular the exotic 2-compact group DI(4), constructed by Dwyer-Wilkerson, is the only simple 2-compact group not arising as the 2-completion of a compact connected Lie group. Combined with our earlier work with Moeller and Viruel for p odd, this establishes the full classification of p-compact groups, stating that, up to isomorphism, there is a one-to-one correspondence between connected p-compact gr...

  10. Compactness in fuzzy function spaces

    African Journals Online (AJOL)

    In [3] we defined a notion of compactness in FCS, the category of fuzzy convergence spaces as defined by Lowen/Lowen/Wuyts [8]. In their paper the latter also introduced a fuzzy convergence structure c-lim for fuzzy function spaces thus proving that FCS is a topological quasitopos. In this paper we start the investigation of ...

  11. Permeation characteristics of compacted bentonite

    International Nuclear Information System (INIS)

    Banno, Katsunori; Nishi, Kenji; Yoshida, Hiroshi

    1991-01-01

    Bentonite has properties such as impermeability, hygroscopic swelling, which seem to make it a promising water cut-off material. In this research, performance tests were conducted with various types of compacted bentonite toward the application of bentonite to cut-off technology. (author)

  12. Learning from the Jordan Compact

    Directory of Open Access Journals (Sweden)

    Katharina Lenner

    2018-02-01

    Full Text Available Analysis of the implementation of the Jordan Compact offers three key lessons: governmental approval is important but not sufficient, the incorporation of critical voices is crucial, and meeting numeric targets is not the same as achieving underlying goals.

  13. Mesoscale Simulations of Power Compaction

    Energy Technology Data Exchange (ETDEWEB)

    Lomov, I; Fujino, D; Antoun, T; Liu, B

    2009-08-06

    Mesoscale 3D simulations of metal and ceramic powder compaction in shock waves have been performed with an Eulerian hydrocode GEODYN. The approach was validated by simulating shock compaction of porous well-characterized ductile metal using Steinberg material model. Results of the simulations with handbook values for parameters of solid 2024 aluminum have good agreement with experimental compaction curves and wave profiles. Brittle ceramic materials are not so well studied as metals, so material model for ceramic (tungsten carbide) has been fitted to shock compression experiments of non-porous samples and further calibrated to match experimental compaction curves. Direct simulations of gas gun experiments with ceramic powder have been performed and showed good agreement with experimental data. Numerical shock wave profile has same character and thickness as measured with VISAR. Numerical results show reshock states above the single-shock Hugoniot line also observed in experiments. They found that to receive good quantitative agreement with experiment it is essential to perform 3D simulations.

  14. Engineering aspects of compact stellarators

    International Nuclear Information System (INIS)

    Nelson, B.E.; Benson, R.D.; Brooks, A.

    2003-01-01

    Compact stellarators could combine the good confinement and high beta of a tokamak with the inherently steady state, disruption-free characteristics of a stellarator. Two U.S. compact stellarator facilities are now in the conceptual design phase: the National Compact Stellarator Experiment (NCSX) and the Quasi- Poloidal Stellarator (QPS). NCSX has a major radius of 1.4 m and a toroidal field up to 2 T. The primary feature of both NCSX and QPS is the set of modular coils that provide the basic magnetic configuration. These coils represent a major engineering challenge due to the complex shape, precise geometric accuracy, and high current density of the windings. The winding geometry is too complex for conventional hollow copper conductor construction. Instead, the modular coils will be wound with flexible, multi strand cable conductor that has been compacted to a 75% copper packing fraction. Inside the NCSX coil set and surrounding the plasma is a highly contoured vacuum vessel. The vessel consists of three identical, 120 deg. segments that are bolted together at double sealed joints. The QPS device has a major radius of 0.9 m, a toroidal field of 1 T, and an aspect ratio of only 2.7. Instead of an internal vacuum vessel, the QPS modular coils will operate in an external vacuum tank. (author)

  15. Compactness of eventually different families

    DEFF Research Database (Denmark)

    Schrittesser, David

    2018-01-01

    We show that there is an effectively closed maximal eventually different family in spaces of the form ∏ An with each An countable and discrete (for example, Baire space) and give an exact criterion for when there exists an effectively compact such family. The proof generalizes and simplifies...

  16. DNA compaction by nonbinding macromolecules

    NARCIS (Netherlands)

    Vries, de R.J.

    2012-01-01

    Compaction of DNA by nonbinding macromolecules such as uncharged flexible polymer chains and negatively charged globular proteins is thought to have various applications in biophysics, for example in the formation of a nucleoid structure in bacteria. A simple experimental model that has been very

  17. Compact He-Ne lasers

    Science.gov (United States)

    Eskin, N. I.; Ischenko, P. I.; Kozel, Stanislav M.; Kaplitsky, V. E.; Kononenko, V. I.

    1999-01-01

    The presented laser is a brand new elaboration of the compact gas laser with longitudinal excitation. This development has no analogues and is protected by the patent of Russia. Its main features are: monoblock construction of the had, internal mirrors, optical contact, small size and weight, long term of work and storage.

  18. Dynamic compaction of ceramic powders

    Energy Technology Data Exchange (ETDEWEB)

    Cline, C.F.

    1982-06-10

    Dynamic consolidation is a technique for densifying powder ensembles to near theoretical with or without external application of heat. The technique itself is simple: the confined powder, initially at a green density of approx. 50% encounters a high pressure shock wave which exceeds the yield strength and densifies as the wave proceeds through the compact. The time scales and pressure range from 1-10's of microseconds and 10-100's of kilobars (10 Kb = 1 GPa). The short time scale of the pressure pulse during the compaction stage inhibits kinetic processes which have longer time constants. The pressure pulse can be delivered to the green compact by a number of techniques, i.e. high explosive, projectile. The methods differ in the degree that one can control the amplitude, duration, and nature of the pressure pulse. The lecture compares powders compacted by explosive and light gas guns and when possible characterize their resulting structures and properties, using AlN as example. 14 figures.

  19. Meniscal shear stress for punching

    NARCIS (Netherlands)

    Tuijthof, Gabrielle J. M.; Meulman, Hubert N.; Herder, Just L.; van Dijk, C. Niek

    2009-01-01

    Aim: Experimental determination of the shear stress for punching meniscal tissue. Methods: Meniscectomy (surgical treatment of a lesion of one of the menisci) is the most frequently performed arthroscopic procedure. The performance of a meniscectomy is not optimal with the currently available

  20. In vivo shear stress response.

    Science.gov (United States)

    Egginton, Stuart

    2011-12-01

    EC (endothelial cell) responses to shear stress generated by vascular perfusion play an important role in circulatory homoeostasis, whereas abnormal responses are implicated in vascular diseases such as hypertension and atherosclerosis. ECs subjected to high shear stress in vitro alter their morphology, function and gene expression. The molecular basis for mechanotransduction of a shear stress signal, and the identity of the sensing mechanisms, remain unclear with many candidates under investigation. Translating these findings in vivo has proved difficult. The role of VEGF (vascular endothelial growth factor) flow-dependent nitric oxide release in remodelling skeletal muscle microcirculation is established for elevated (activity, dilatation) and reduced (overload, ischaemia) shear stress, although their temporal relationship to angiogenesis varies. It is clear that growth factor levels may offer only a permissive environment, and alteration of receptor levels may be a viable therapeutic target. Angiogenesis in vivo appears to be a graded phenomenon, and capillary regression on withdrawal of stimulus may be rapid. Combinations of physiological angiogenic stimuli appear not to be additive.

  1. Squatting-Related Tibiofemoral Shear Reaction Forces and a Biomechanical Rationale for Femoral Component Loosening

    Directory of Open Access Journals (Sweden)

    Ashvin Thambyah

    2014-01-01

    Full Text Available Previous gait studies on squatting have described a rapid reversal in the direction of the tibiofemoral joint shear reaction force when going into a full weight-bearing deep knee flexion squat. The effects of such a shear reversal have not been considered with regard to the loading demand on knee implants in patients whose activities of daily living require frequent squatting. In this paper, the shear reversal effect is discussed and simulated in a finite element knee implant-bone model, to evaluate the possible biomechanical significance of this effect on femoral component loosening of high flexion implants as reported in the literature. The analysis shows that one of the effects of the shear reversal was a switch between large compressive and large tensile principal strains, from knee extension to flexion, respectively, in the region of the anterior flange of the femoral component. Together with the known material limits of cement and bone, this large mismatch in strains as a function of knee position provides new insight into how and why knee implants may fail in patients who perform frequent squatting.

  2. Compaction and relaxation of biofilms

    KAUST Repository

    Valladares Linares, R.

    2015-06-18

    Operation of membrane systems for water treatment can be seriously hampered by biofouling. A better characterization of biofilms in membrane systems and their impact on membrane performance may help to develop effective biofouling control strategies. The objective of this study was to determine the occurrence, extent and timescale of biofilm compaction and relaxation (decompaction), caused by permeate flux variations. The impact of permeate flux changes on biofilm thickness, structure and stiffness was investigated in situ and non-destructively with optical coherence tomography using membrane fouling monitors operated at a constant crossflow velocity of 0.1 m s−1 with permeate production. The permeate flux was varied sequentially from 20 to 60 and back to 20 L m−2 h−1. The study showed that the average biofilm thickness on the membrane decreased after elevating the permeate flux from 20 to 60 L m−2 h−1 while the biofilm thickness increased again after restoring the original flux of 20 L m−2 h−1, indicating the occurrence of biofilm compaction and relaxation. Within a few seconds after the flux change, the biofilm thickness was changed and stabilized, biofilm compaction occurred faster than the relaxation after restoring the original permeate flux. The initial biofilm parameters were not fully reinstated: the biofilm thickness was reduced by 21%, biofilm stiffness had increased and the hydraulic biofilm resistance was elevated by 16%. Biofilm thickness was related to the hydraulic biofilm resistance. Membrane performance losses are related to the biofilm thickness, density and morphology, which are influenced by (variations in) hydraulic conditions. A (temporarily) permeate flux increase caused biofilm compaction, together with membrane performance losses. The impact of biofilms on membrane performance can be influenced (increased and reduced) by operational parameters. The article shows that a (temporary) pressure increase leads to more

  3. Reversed-Field Pinch plasma model

    International Nuclear Information System (INIS)

    Miley, G.H.; Nebel, R.A.; Moses, R.W.

    1979-01-01

    The stability of a Reversed-Field Pinch (RFP) is strongly dependent on the plasma profile and the confining sheared magnetic field. Magnetic diffusion and thermal transport produce changing conditions of stability. Despite the limited understanding of RFP transport, modelling is important to predict general trends and to study possible field programming options. To study the ZT-40 experiment and to predict the performance of future RFP reactors, a one-dimensional transport code has been developed. This code includes a linear, ideal MHD stability check based on an energy principle. The transport section integrates plasma profiles forward in time while the stability section periodically checks the stability of the evolving plasma profile

  4. The shear-free condition and constant-mean-curvature hyperboloidal initial data

    International Nuclear Information System (INIS)

    Allen, Paul T; Allen, Iva Stavrov; Isenberg, James; Lee, John M

    2016-01-01

    We consider the Einstein–Maxwell-fluid constraint equations, and make use of the conformal method to construct and parametrize constant-mean-curvature hyperboloidal initial data sets that satisfy the shear-free condition. This condition is known to be necessary in order that a spacetime development admit a regular conformal boundary at future null infinity; see (Andersson and Chruściel 1994 Commun. Math. Phys. 161 533–68). We work with initial data sets in a variety of regularity classes, primarily considering those data sets whose geometries are weakly asymptotically hyperbolic , as defined in (Allen et al 2015 arXiv:1506.03399). These metrics are C 1,1 conformally compact, but not necessarily C 2 conformally compact. In order to ensure that the data sets we construct are indeed shear-free, we make use of the conformally covariant traceless Hessian introduced in (Allen et al 2015 arXiv:1506.03399). We furthermore construct a class of initial data sets with weakly asymptotically hyerbolic metrics that may be only C 0,1 conformally compact; these data sets are insufficiently regular to make sense of the shear-free condition. (paper)

  5. Fourier band-power E/B-mode estimators for cosmic shear

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Matthew R.; Rozo, Eduardo

    2016-01-20

    We introduce new Fourier band-power estimators for cosmic shear data analysis and E/B-mode separation. We consider both the case where one performs E/B-mode separation and the case where one does not. The resulting estimators have several nice properties which make them ideal for cosmic shear data analysis. First, they can be written as linear combinations of the binned cosmic shear correlation functions. Secondly, they account for the survey window function in real-space. Thirdly, they are unbiased by shape noise since they do not use correlation function data at zero separation. Fourthly, the band-power window functions in Fourier space are compact and largely non-oscillatory. Fifthly, they can be used to construct band-power estimators with very efficient data compression properties. In particular, we find that all of the information on the parameters Ωm, σ8 and ns in the shear correlation functions in the range of ~10–400 arcmin for single tomographic bin can be compressed into only three band-power estimates. Finally, we can achieve these rates of data compression while excluding small-scale information where the modelling of the shear correlation functions and power spectra is very difficult. Given these desirable properties, these estimators will be very useful for cosmic shear data analysis.

  6. Kinetic Stability of the Field Reversed Configuration

    International Nuclear Information System (INIS)

    E.V. Belova; R.C. Davidson; H. Ji; and M. Yamada

    2002-01-01

    New computational results are presented which advance the understanding of the stability properties of the Field-Reversed Configuration (FRC). The FRC is an innovative confinement approach that offers a unique fusion reactor potential because of its compact and simple geometry, translation properties, and high plasma beta. One of the most important issues is FRC stability with respect to low-n (toroidal mode number) MHD modes. There is a clear discrepancy between the predictions of standard MHD theory that many modes should be unstable on the MHD time scale, and the observed macroscopic resilience of FRCs in experiments

  7. Seismic Behaviour of Composite Steel Fibre Reinforced Concrete Shear Walls

    Science.gov (United States)

    Boita, Ioana-Emanuela; Dan, Daniel; Stoian, Valeriu

    2017-10-01

    In this paper is presented an experimental study conducted at the “Politehnica” University of Timisoara, Romania. This study provides results from a comprehensive experimental investigation on the behaviour of composite steel fibre reinforced concrete shear walls (CSFRCW) with partially or totally encased profiles. Two experimental composite steel fibre reinforced concrete walls (CSFRCW) and, as a reference specimen, a typical reinforced concrete shear wall (RCW), (without structural reinforcement), were fabricated and tested under constant vertical load and quasi-static reversed cyclic lateral loads, in displacement control. The tests were performed until failure. The tested specimens were designed as 1:3 scale steel-concrete composite elements, representing a three storeys and one bay element from the base of a lateral resisting system made by shear walls. Configuration/arrangement of steel profiles in cross section were varied within the specimens. The main objective of this research consisted in identifying innovative solutions for composite steel-concrete shear walls with enhanced performance, as steel fibre reinforced concrete which was used in order to replace traditional reinforced concrete. A first conclusion was that replacing traditional reinforcement with steel fibre changes the failure mode of the elements, as from a flexural mode, in case of element RCW, to a shear failure mode for CSFRCW. The maximum lateral force had almost similar values but test results indicated an improvement in cracking response, and a decrease in ductility. The addition of steel fibres in the concrete mixture can lead to an increase of the initial cracking force, and can change the sudden opening of a crack in a more stable process.

  8. Development of Test Method for Simple Shear and Prediction of Hardening Behavior Considering the Branchings Effect

    International Nuclear Information System (INIS)

    Kim, Dongwook; Bang, Sungsik; Kim, Minsoo; Lee, Hyungyil; Kim, Naksoo

    2013-01-01

    In this study we establish a process to predict hardening behavior considering the Branchings effect for zircaloy-4 sheets. When a metal is compressed after tension in forming, the yield strength decreases. For this reason, the Branchings effect should be considered in FE simulations of spring-back. We suggested a suitable specimen size and a method for determining the optimum tightening torque for simple shear tests. Shear stress-strain curves are obtained for five materials. We developed a method to convert the shear load-displacement curve to the effective stress-strain curve with Fea. We simulated the simple shear forward/reverse test using the combined isotropic/kinematic hardening model. We also investigated the change of the load-displacement curve by varying the hardening coefficients. We determined the hardening coefficients so that they follow the hardening behavior of zircaloy-4 in experiments

  9. Development of Test Method for Simple Shear and Prediction of Hardening Behavior Considering the Branchings Effect

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dongwook; Bang, Sungsik; Kim, Minsoo; Lee, Hyungyil; Kim, Naksoo [Sogang Univ., Seoul (Korea, Republic of)

    2013-10-15

    In this study we establish a process to predict hardening behavior considering the Branchings effect for zircaloy-4 sheets. When a metal is compressed after tension in forming, the yield strength decreases. For this reason, the Branchings effect should be considered in FE simulations of spring-back. We suggested a suitable specimen size and a method for determining the optimum tightening torque for simple shear tests. Shear stress-strain curves are obtained for five materials. We developed a method to convert the shear load-displacement curve to the effective stress-strain curve with Fea. We simulated the simple shear forward/reverse test using the combined isotropic/kinematic hardening model. We also investigated the change of the load-displacement curve by varying the hardening coefficients. We determined the hardening coefficients so that they follow the hardening behavior of zircaloy-4 in experiments.

  10. Engineering design of a compact RFP reactor (CRFPR)

    International Nuclear Information System (INIS)

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

    1983-01-01

    The results of a previously-reported comprehensive parametric systems analysis of the Reversed-Field Pinch (RFP) give strong indications for minimum-cost systems that would operate with resistive water-cooled copper coils and higher first-wall neutron current (15 to 20 MW/m 2 ). These minimum-cost, compact RFP reactors (CRFPRs) have system power densities that can be comparable with fission power plants and, therefore, are 10 to 30 times smaller than most superconducting approaches. Reported herein are initial results of a conceptual engineering design of key fusion-power-core (FPC) subsystems

  11. Influence of wood-derived biochar on the compactibility and strength of silt loam soil

    Science.gov (United States)

    Ahmed, Ahmed; Gariepy, Yvan; Raghavan, Vijaya

    2017-04-01

    Biochar is proven to enhance soil fertility and increase crop productivity. Given that the influence of biochar on soil compaction remains unclear, selected physico-mechanical properties of soil amended with wood-derived biochar were assessed. For unamended silt loam, the bulk density, maximum bulk density, optimum moisture content, plastic limit, liquid limit, and plasticity index were 1.05 Mg m-3, 1.69 Mg m-3, 16.55, 17.1, 29.3, and 12.2%, respectively. The penetration resistance and shear strength of the unamended silt loam compacted in the standard compaction Proctor mold and at its optimum moisture content were 1800 kPa and 850 kPa, respectively. Results from amending the silt loam with 10% particle size ranges (0.5-212 μm) led to relative decreases of 18.1, 17.75, 66.66, and 97.4% in bulk density, maximum bulk density, penetration resistance, and shear strength, respectively; a 26.8% relative increase in optimum moisture content; along with absolute increases in plastic limit, liquid limit, and plasticity index of 5.3, 13.7, and 8.4%, respectively. While the biochar-amended silt loam soil was more susceptible to compaction, however, soil mechanical impedance enhanced.

  12. Reversible flowchart languages and the structured reversible program theorem

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2008-01-01

    operators. Reversible flowcharts are r- Turing-complete, meaning that they can simuluate reversible Turing machines without garbage data. We also demonstrate the injectivization of classical flowcharts into reversible flowcharts. The reversible flowchart computation model provides a theoretical...

  13. Rate type isotach compaction of consolidated sandstone

    NARCIS (Netherlands)

    Waal, J.A. de; Thienen-Visser, K. van; Pruiksma, J.P.

    2015-01-01

    Laboratory experiments on samples from a consolidated sandstone reservoir are presented that demonstrate rate type compaction behaviour similar to that observed on unconsolidated sands and soils. Such rate type behaviour can have large consequences for reservoir compaction, surface subsidence and

  14. Sequential normal compactness versur topological normal compactness in variational analysis

    Czech Academy of Sciences Publication Activity Database

    Fabian, Marián; Mordukhovich, B. S.

    2003-01-01

    Roč. 54, č. 6 (2003), s. 1057-1067 ISSN 0362-546X R&D Projects: GA ČR GA201/01/1198 Institutional research plan: CEZ:AV0Z1019905; CEZ:AV0Z1019905 Keywords : variational analysis * sequential and topological normal compactness * Banach spaces Subject RIV: BA - General Mathematics Impact factor: 0.354, year: 2003

  15. Shear behaviour of reinforced phyllite concrete beams

    International Nuclear Information System (INIS)

    Adom-Asamoah, Mark; Owusu Afrifa, Russell

    2013-01-01

    Highlights: ► Phyllite concrete beams often exhibited shear with anchorage bond failure. ► Different shear design provisions for reinforced phyllite beams are compared. ► Predicted shear capacity of phyllite beams must be modified by a reduction factor. -- Abstract: The shear behaviour of concrete beams made from phyllite aggregates subjected to monotonic and cyclic loading is reported. First diagonal shear crack load of beams with and without shear reinforcement was between 42–58% and 42–92% of the failure loads respectively. The phyllite concrete beams without shear links had lower post-diagonal cracking shear resistance compared to corresponding phyllite beams with shear links. As a result of hysteretic energy dissipation, limited cyclic loading affected the stiffness, strength and deformation of the phyllite beams with shear reinforcement. Generally, beams with and without shear reinforcement showed anchorage bond failure in addition to the shear failure due to high stress concentration near the supports. The ACI, BS and EC codes are conservative for the prediction of phyllite concrete beams without shear reinforcement but they all overestimate the shear strength of phyllite concrete beams with shear reinforcement. It is recommended that the predicted shear capacity of phyllite beams reinforced with steel stirrups be modified by a reduction factor of 0.7 in order to specify a high enough safety factor on their ultimate strength. It is also recommended that susceptibility of phyllite concrete beams to undergo anchorage bond failure is averted in design by the provision of greater anchorage lengths than usually permitted.

  16. Shear viscosity of the quark matter

    OpenAIRE

    Iwasaki, Masaharu; Ohnishi, Hiromasa; Fukutome, Takahiko

    2007-01-01

    We discuss shear viscosity of the quark matter by using Kubo formula. The shear viscosity is calculated in the framework of the quasi-particle RPA for the Nambu-Jona-Lasinio model. We obtain a formula that the shear viscosity is expressed by the quadratic form of the quark spectral function in the chiral symmetric phase. The magnitude of the shear viscosity is discussed assuming the Breit-Wigner type for the spectral function.

  17. UV written compact broadband optical couplers

    DEFF Research Database (Denmark)

    Olivero, Massimo; Svalgaard, Mikael

    2005-01-01

    In this paper the first demonstration of compact asymmetric directional couplers made by UV writing is presented. The combined performance in terms bandwidth, loss and compactness exceeds that reported using other, more elaborate fabrication techniques.......In this paper the first demonstration of compact asymmetric directional couplers made by UV writing is presented. The combined performance in terms bandwidth, loss and compactness exceeds that reported using other, more elaborate fabrication techniques....

  18. Evaluation of Shear Resisting Capacity of a Prestressed Concrete Containment Building with Steel or Polyamide Fiber Reinforcement

    Energy Technology Data Exchange (ETDEWEB)

    Choun, Youngsun; Park, Junhee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Conventional reinforced concrete (RC) members generally show a rapid deterioration in shear resisting mechanisms under a reversed cyclic load. However, the use of high-performance fiber-reinforced cement composites provides excellent damage tolerance under large displacement reversals compared with regular concrete. Previous experimental studies have indicated that the use of fibers in conventional RC can enhance the structural and functional performance of prestressed concrete containment buildings (PCCBs) in nuclear power plants. This study evaluates the shear resisting capacity for a PCCB constructed using steel fiber reinforced concrete (SFRC) or polyamide fiber reinforced concrete (PFRC). The effects of steel and polyamide fibers on the shear performance of a PCCB were investigated. It was revealed that steel fibers are more effective to enhance the shear resisting capacity of a PCCB than polyamide fibers. The ductility and energy dissipation increase significantly in fiber reinforced PCCBs.

  19. Shear assessment of reinforced concrete slab bridges

    NARCIS (Netherlands)

    Lantsoght, E.O.L.; Van der Veen, C.; Walraven, J.C.; De Boer, A.

    2013-01-01

    The capacity of reinforced concrete solid slab bridges in shear is assessed by comparing the design beam shear resistance to the design value of the applied shear force due to the permanent actions and live loads. Results from experiments on half-scale continuous slab bridges are used to develop a

  20. Equationally Compact Acts : Coproducts / Peeter Normak

    Index Scriptorium Estoniae

    Normak, Peeter

    1998-01-01

    In this article equational compactness of acts and its generalizations are discussed. As equational compactness does not carry over to coproducts a slight generalization of c-equational campactness is introduced. It is proved that a coproduct of acts is c-equationally compact if and only if all components are c-equationally campact

  1. Invariant subsets under compact quantum group actions

    OpenAIRE

    Huang, Huichi

    2012-01-01

    We investigate compact quantum group actions on unital $C^*$-algebras by analyzing invariant subsets and invariant states. In particular, we come up with the concept of compact quantum group orbits and use it to show that countable compact metrizable spaces with infinitely many points are not quantum homogeneous spaces.

  2. On the persistence of adiabatic shear bands

    Directory of Open Access Journals (Sweden)

    Bassim M.N.

    2012-08-01

    Full Text Available It is generally agreed that the initiation and development of adiabatic shear bands (ASBs are manifestations of damage in metallic materials subjected to high strain rates and large strains as those due to impact in a Hopkinson Bar system. Models for evolution of these bands have been described in the literature. One question that has not received attention is how persistent these bands are and whether their presence and effect can be reversed or eliminated by using a process of thermal (heat treatment or thermo-mechanical treatment that would relieve the material from the high strain associated with ASBs and their role as precursors to crack initiation and subsequent failure. Since ASBs are more prevalent and more defined in BCC metals including steels, a study was conducted to investigate the best conditions of generating ASBs in a heat treatable steel, followed by determining the best conditions for heat treatment of specimens already damaged by the presence of ASBs in order to relieve the strains due to ASBs and restore the material to an apparent microstructure without the “scars” due to the previous presence of ASBs. It was found that heat treatment achieves the curing from ASBs. This presentation documents the process undertaken to achieve this objective.

  3. Compact analyzer: an interactive simulator

    International Nuclear Information System (INIS)

    Ipakchi, A.; Khadem, M.; Colley, R.W.

    1985-01-01

    Compact Analyzer is a computer system that combines dynamic simulation models with interactive and color graphics user interface functions to provide a cost-effective simulator for dynamic analysis and evaluation of power plant operation, with engineering and training applications. Most dynamic simulation packages such as RETRAN and TRAC are designed for a batch-mode operation. With advancements in computer technology and man/machine interface capabilities, it is possible to integrate such codes with interactive and graphic functions into advanced simulators. The US Nuclear Regulatory Commission has sponsored development of plant analyzers with such characteristics. The Compact Analyzer is an Electric Power Research Institute (EPRI)-sponsored project, which currently utilizes the EPRI modular modeling system (MMS) for process simulation, and uses an adaptable color graphic package for dynamic display of the simulation results

  4. Probability on compact Lie groups

    CERN Document Server

    Applebaum, David

    2014-01-01

    Probability theory on compact Lie groups deals with the interaction between “chance” and “symmetry,” a beautiful area of mathematics of great interest in its own sake but which is now also finding increasing applications in statistics and engineering (particularly with respect to signal processing). The author gives a comprehensive introduction to some of the principle areas of study, with an emphasis on applicability. The most important topics presented are: the study of measures via the non-commutative Fourier transform, existence and regularity of densities, properties of random walks and convolution semigroups of measures, and the statistical problem of deconvolution. The emphasis on compact (rather than general) Lie groups helps readers to get acquainted with what is widely seen as a difficult field but which is also justified by the wealth of interesting results at this level and the importance of these groups for applications. The book is primarily aimed at researchers working in probability, s...

  5. Compact sources for eyesafe illumination

    Science.gov (United States)

    Baranova, Nadia; Pu, Rui; Stebbins, Kenneth; Bystryak, Ilya; Rayno, Michael; Ezzo, Kevin; DePriest, Christopher

    2018-02-01

    Q-peak has demonstrated a compact, pulsed eyesafe laser architecture operating with >10 mJ pulse energies at repetition rates as high as 160 Hz. The design leverages an end-pumped solid-state laser geometry to produce adequate eyesafe beam quality (M2˜4), while also providing a path toward higher-density laser architectures for pulsed eyesafe applications. The baseline discussed in this paper has shown a unique capability for high-pulse repetition rates in a compact package, and offers additional potential for power scaling based on birefringence compensation. The laser consists of an actively Q-switched oscillator cavity producing pulse widths designed to fit within a volume of 3760 cm3. We will discuss details of the optical system design, modeled thermal effects and stress-induced birefringence, as well as experimental advantages of the end-pumped laser geometry, along with proposed paths to higher eyesafe pulse energies.

  6. Intra-Continental Deformation by Mid-Crustal Shearing and Doming in a Cenozoic Compressive Setting Along the Ailao Shan-Red River Shear Zone

    Science.gov (United States)

    Zhang, B.

    2016-12-01

    Large-scale lateral strike-slip shear zones have been a key point in the debate about the deformation mechanisms of Asia in response to the India-Asia collision. The exhumed gneiss has been attributed to lateral strike-slip shear zone. This hypothesis has been challenged by recent discoveries indicating that a contractional doming deformation prior to the initiation of lateral strike-slip shearing. The Cenozoic Xuelong Shan antiformal dome is located at the northern segment of the Ailao Shan-Red River shear zone. Subhorizontal foliation in the gneiss core are recognized, representing a broad top-to-NE shear initiated under amphibolite facies conditions and propagated into greenschist facies in the mantling schist and strike-slip shear zone. Quartz CPOs and opening angles of crossed girdle fabrics in quartz suggest that the deformation temperatures increased with increasing structural depth from 300-500 °C in the mantling schist to ≥650 °C in the gneissic core. This trend is mirrored by variations in the metamorphic grade of the syn-kinematic mineral assemblages and microstructures, which ranges from garnet + amphibole + biotite + sillimanite + rutite + feldspar in the core to garnet + staurolite + biotite + epidote + muscovite within the limb units. Five-stage deformation is identified: (1) a broad top-to-NE shear in the subhorizontal level (D1); (2) opposing reverse-sense shear along the two schist limbs of the dome during contraction-related doming (D2-D3); (3) sinistral strike-slip shearing within the eastern limb (D4); and (4) extensional deformation (D5). The antiformal dome formation had been roughly coeval with top-to-NE ductile shearing in the mid-crust at 32 Ma or earlier. The geometries of the antiformal dome in the Xuelong Shan dome are similar to those associated with the antiform in the Dai Nui Con Voi, Diancang Shan and Ailao Shan zones. It is likely that the complex massifs, which define a regional linear gneiss dome zone in Cenozoic intra

  7. Effect of Shear Applied During a Pharmaceutical Process on Near Infrared Spectra.

    Science.gov (United States)

    Hernández, Eduardo; Pawar, Pallavi; Rodriguez, Sandra; Lysenko, Sergiy; Muzzio, Fernando J; Romañach, Rodolfo J

    2016-03-01

    This study describes changes observed in the near-infrared (NIR) diffuse reflectance (DR) spectra of pharmaceutical tablets after these tablets were subjected to different levels of strain (exposure to shear) during the mixing process. Powder shearing is important in the mixing of powders that are cohesive. Shear stress is created in a system by moving one surface over another causing displacements in the direction of the moving surface and is part of the mixing dynamics of particulates in many industries including the pharmaceutical industry. In continuous mixing, shear strain is developed within the process when powder particles are in constant movement and can affect the quality attributes of the final product such as dissolution. These changes in the NIR spectra could affect results obtained from NIR calibration models. The aim of the study was to understand changes in the NIR diffuse reflectance spectra that can be associated with different levels of strain developed during blend shearing of laboratory samples. Shear was applied using a Couette cell and tablets were produced using a tablet press emulator. Tablets with different shear levels were measured using NIR spectroscopy in the diffuse reflectance mode. The NIR spectra were baseline corrected to maintain the scattering effect associated with the physical properties of the tablet surface. Principal component analysis was used to establish the principal sources of variation within the samples. The angular dependence of elastic light scattering shows that the shear treatment reduces the size of particles and produces their uniform and highly isotropic distribution. Tablet compaction further reduces the diffuse component of scattering due to realignment of particles. © The Author(s) 2016.

  8. Magma shearing and friction in the volcanic conduit: A crystal constraint

    Science.gov (United States)

    Wallace, P. A.; Kendrick, J. E.; Henton De Angelis, S.; Ashworth, J. D.; Coats, R.; Miwa, T.; Mariani, E.; Lavallée, Y.

    2017-12-01

    Magma shearing and friction processes in the shallow volcanic conduit are typical manifestations of strain localisation, which in turn can have an influential role on magma ascent dynamics. The thermal consequences of such events could drive the destabilisation of magma and thus dictate the style of activity at the surface. Shear heating and fault friction are prime candidates for the generation of significant quantities of heat. Here we use a combination of field and experimental evidence to investigate how crystals can act as sensitive recorders of both physical and chemical processes occurring in the shallow volcanic conduit. Spine extrusion during the closing of the 1991-95 eruption at Unzen volcano, Japan, provided the unique opportunity to investigate marginal shear zone formation, which preserves a relic of the deformation during magma ascent. Our results show that crystals can effectively act as a deformation marker during magma ascent through the viscous-brittle transition by accommodating strain in the form of crystal plasticity before fracturing (comminution). Electron backscatter diffraction (EBSD) reveals up to 40° lattice distortion of biotite phenocrysts in zones of high shear, with negligible plasticity further away. Plagioclase microlites display a systematic plastic response to an increase in shear intensity, as recorded by an increase in lattice distortion towards the spine margin of up to 9°. This localisation of strain within the shear zone is also accompanied by the destabilisation of hydrous mineral phases (i.e. amphibole), compaction of pores (23-13% Φ), glass devitrification and magnetic anomalies. The narrow zone of disequilibrium textures suggests the likely effect of a thermal input due to strain localisation being the contributing factor. These observations are complimented by high-temperature high-velocity rotary shear experiments which simulate the deformation evolution during shear. Hence, understanding these shallow volcanic

  9. Statistical Model of Extreme Shear

    DEFF Research Database (Denmark)

    Hansen, Kurt Schaldemose; Larsen, Gunner Chr.

    2005-01-01

    In order to continue cost-optimisation of modern large wind turbines, it is important to continuously increase the knowledge of wind field parameters relevant to design loads. This paper presents a general statistical model that offers site-specific prediction of the probability density function...... (PDF) of turbulence driven short-term extreme wind shear events, conditioned on the mean wind speed, for an arbitrary recurrence period. The model is based on an asymptotic expansion, and only a few and easily accessible parameters are needed as input. The model of the extreme PDF is supplemented...... by a model that, on a statistically consistent basis, describes the most likely spatial shape of an extreme wind shear event. Predictions from the model have been compared with results from an extreme value data analysis, based on a large number of full-scale measurements recorded with a high sampling rate...

  10. Statistical Model of Extreme Shear

    DEFF Research Database (Denmark)

    Larsen, Gunner Chr.; Hansen, Kurt Schaldemose

    2004-01-01

    In order to continue cost-optimisation of modern large wind turbines, it is important to continously increase the knowledge on wind field parameters relevant to design loads. This paper presents a general statistical model that offers site-specific prediction of the probability density function...... (PDF) of turbulence driven short-term extreme wind shear events, conditioned on the mean wind speed, for an arbitrary recurrence period. The model is based on an asymptotic expansion, and only a few and easily accessible parameters are needed as input. The model of the extreme PDF is supplemented...... by a model that, on a statistically consistent basis, describe the most likely spatial shape of an extreme wind shear event. Predictions from the model have been compared with results from an extreme value data analysis, based on a large number of high-sampled full-scale time series measurements...

  11. Strange matter in compact stars

    Science.gov (United States)

    Klähn, Thomas; Blaschke, David B.

    2018-02-01

    We discuss possible scenarios for the existence of strange matter in compact stars. The appearance of hyperons leads to a hyperon puzzle in ab-initio approaches based on effective baryon-baryon potentials but is not a severe problem in relativistic mean field models. In general, the puzzle can be resolved in a natural way if hadronic matter gets stiffened at supersaturation densities, an effect based on the quark Pauli quenching between hadrons. We explain the conflict between the necessity to implement dynamical chiral symmetry breaking into a model description and the conditions for the appearance of absolutely stable strange quark matter that require both, approximately masslessness of quarks and a mechanism of confinement. The role of strangeness in compact stars (hadronic or quark matter realizations) remains unsettled. It is not excluded that strangeness plays no role in compact stars at all. To answer the question whether the case of absolutely stable strange quark matter can be excluded on theoretical grounds requires an understanding of dense matter that we have not yet reached.

  12. Durability of Self Compacting Concrete

    International Nuclear Information System (INIS)

    Benmarce, A.; Boudjehem, H.; Bendjhaiche, R.

    2011-01-01

    Self compacting concrete (SCC) seem to be a very promising materials for construction thanks to their properties in a fresh state. Studying of the influence of the parameters of specific designed mixes to their mechanical, physical and chemical characteristics in a state hardened is an important stage so that it can be useful for new-to-the-field researchers and designers (worldwide) beginning studies and work involving self compacting concrete. The objective of this research is to study the durability of self compacting concrete. The durability of concrete depends very much on the porosity; the latter determines the intensity of interactions with aggressive agents. The pores inside of concrete facilitate the process of damage, which began generally on the surface. We are interested to measure the porosity of concrete on five SCC with different compositions (w/c, additives) and vibrated concrete to highlight the influence of the latter on the porosity, thereafter on the compressive strength and the transfer properties (oxygen permeability, chloride ion diffusion, capillary absorption). (author)

  13. Introduction to reversible computing

    CERN Document Server

    Perumalla, Kalyan S

    2013-01-01

    Few books comprehensively cover the software and programming aspects of reversible computing. Filling this gap, Introduction to Reversible Computing offers an expanded view of the field that includes the traditional energy-motivated hardware viewpoint as well as the emerging application-motivated software approach. Collecting scattered knowledge into one coherent account, the book provides a compendium of both classical and recently developed results on reversible computing. It explores up-and-coming theories, techniques, and tools for the application of rever

  14. Recent Progress in MHD Stability Calculations of Compact Stellarators

    International Nuclear Information System (INIS)

    Fu, G.Y.; Ku, L.P.; Redi, M.H.; Kessel, C.; Monticello, D.A.; Reiman, A.; Cooper, W.A.; Nuehrenberg, C.; Sanchez, R.; Ware, A.; Hirshman, S.P.; Spong, D.A.

    2000-01-01

    A key issue for compact stellarators is the stability of beta-limiting MHD modes, such as external kink modes driven by bootstrap current and pressure gradient. We report here recent progress in MHD stability studies for low-aspect-ratio Quasi-Axisymmetric Stellarators (QAS) and Quasi-Omnigeneous Stellarators (QOS). We find that the N = 0 periodicity-preserving vertical mode is significantly more stable in stellarators than in tokamaks because of the externally generated rotational transform. It is shown that both low-n external kink modes and high-n ballooning modes can be stabilized at high beta by appropriate 3D shaping without a conducting wall. The stabilization mechanism for external kink modes in QAS appears to be an enhancement of local magnetic shear due to 3D shaping. The stabilization of ballooning mode in QOS is related to a shortening of the normal curvature connection length

  15. Shear viscosity of nuclear matter

    Science.gov (United States)

    Magner, A. G.; Gorenstein, M. I.; Grygoriev, U. V.; Plujko, V. A.

    2016-11-01

    Shear viscosity η is calculated for the nuclear matter described as a system of interacting nucleons with the van der Waals (VDW) equation of state. The Boltzmann-Vlasov kinetic equation is solved in terms of the plane waves of the collective overdamped motion. In the frequent-collision regime, the shear viscosity depends on the particle-number density n through the mean-field parameter a , which describes attractive forces in the VDW equation. In the temperature region T =15 -40 MeV, a ratio of the shear viscosity to the entropy density s is smaller than 1 at the nucleon number density n =(0.5 -1.5 ) n0 , where n0=0.16 fm-3 is the particle density of equilibrium nuclear matter at zero temperature. A minimum of the η /s ratio takes place somewhere in a vicinity of the critical point of the VDW system. Large values of η /s ≫1 are, however, found in both the low-density, n ≪n0 , and high-density, n >2 n0 , regions. This makes the ideal hydrodynamic approach inapplicable for these densities.

  16. Advanced radioactive waste compaction techniques: Final report

    International Nuclear Information System (INIS)

    Volodzko, M.; McGrath, R.N.; Kinsman, J.F.; Palo, W.J.

    1988-08-01

    The purpose of this test program is to provide definitive information on the volume reduction capabilities of conventional compactors used in the nuclear industry for the treatment of dry active waste and the effects of preshredding on compaction. The test program presents comprehensive data on compacted densities of dry active waste collected at five facilities generating this waste and using conventional compactors. Waste materials presently classified as ''non-compactable'' which would lend themselves to preshredding and compaction are identified. An ALARA evaluation of shredding operations and an economic evaluation of preshredding prior to compaction are also presented. 32 figs., 72 tabs

  17. Interaction between the Stress Phase Angle (SPA and the Oscillatory Shear Index (OSI Affects Endothelial Cell Gene Expression.

    Directory of Open Access Journals (Sweden)

    Ronny Amaya

    Full Text Available Hemodynamic forces play an important role in the non-uniform distribution of atherosclerotic lesions. Endothelial cells are exposed simultaneously to fluid wall shear stress (WSS and solid circumferential stress (CS. Due to variations in impedance (global factors and geometric complexities (local factors in the arterial circulation a time lag arises between these two forces that can be characterized by the temporal phase angle between CS and WSS (stress phase angle-SPA. Asynchronous flows (SPA close to -180° that are most prominent in coronary arteries have been associated with localization of atherosclerosis. Reversing oscillatory flows characterized by an oscillatory shear index (OSI that is great than zero are also associated with atherosclerosis localization. In this study we examined the relationship between asynchronous flows and reversing flows in altering the expression of 37 genes relevant to atherosclerosis development. In the case of reversing oscillatory flow, we observed that the asynchronous condition upregulated 8 genes compared to synchronous hemodynamics, most of them proatherogenic. Upregulation of the pro-inflammatory transcription factor NFκB p65 was confirmed by western blot, and nuclear translocation of NFκB p65 was confirmed by immunofluorescence staining. A comparative study between non-reversing flow and reversing flow found that in the case of synchronous hemodynamics, reversing flow altered the expression of 11 genes, while in the case of asynchronous hemodynamics, reversing flow altered the expression of 17 genes. Reversing flow significantly upregulated protein expression of NFκB p65 for both synchronous and asynchronous conditions. Nuclear translocation of NFκB p65 was confirmed for synchronous and asynchronous conditions in the presence of flow reversal. These data suggest that asynchronous hemodynamics and reversing flow can elicit proatherogenic responses in endothelial cells compared to synchronous

  18. Interaction between the Stress Phase Angle (SPA) and the Oscillatory Shear Index (OSI) Affects Endothelial Cell Gene Expression.

    Science.gov (United States)

    Amaya, Ronny; Cancel, Limary M; Tarbell, John M

    2016-01-01

    Hemodynamic forces play an important role in the non-uniform distribution of atherosclerotic lesions. Endothelial cells are exposed simultaneously to fluid wall shear stress (WSS) and solid circumferential stress (CS). Due to variations in impedance (global factors) and geometric complexities (local factors) in the arterial circulation a time lag arises between these two forces that can be characterized by the temporal phase angle between CS and WSS (stress phase angle-SPA). Asynchronous flows (SPA close to -180°) that are most prominent in coronary arteries have been associated with localization of atherosclerosis. Reversing oscillatory flows characterized by an oscillatory shear index (OSI) that is great than zero are also associated with atherosclerosis localization. In this study we examined the relationship between asynchronous flows and reversing flows in altering the expression of 37 genes relevant to atherosclerosis development. In the case of reversing oscillatory flow, we observed that the asynchronous condition upregulated 8 genes compared to synchronous hemodynamics, most of them proatherogenic. Upregulation of the pro-inflammatory transcription factor NFκB p65 was confirmed by western blot, and nuclear translocation of NFκB p65 was confirmed by immunofluorescence staining. A comparative study between non-reversing flow and reversing flow found that in the case of synchronous hemodynamics, reversing flow altered the expression of 11 genes, while in the case of asynchronous hemodynamics, reversing flow altered the expression of 17 genes. Reversing flow significantly upregulated protein expression of NFκB p65 for both synchronous and asynchronous conditions. Nuclear translocation of NFκB p65 was confirmed for synchronous and asynchronous conditions in the presence of flow reversal. These data suggest that asynchronous hemodynamics and reversing flow can elicit proatherogenic responses in endothelial cells compared to synchronous hemodynamics without

  19. On Intuitionistic Fuzzy β-Almost Compactness and β-Nearly Compactness.

    Science.gov (United States)

    Renuka, R; Seenivasan, V

    2015-01-01

    The concept of intuitionistic fuzzy β-almost compactness and intuitionistic fuzzy β-nearly compactness in intuitionistic fuzzy topological spaces is introduced and studied. Besides giving characterizations of these spaces, we study some of their properties. Also, we investigate the behavior of intuitionistic fuzzy β-compactness, intuitionistic fuzzy β-almost compactness, and intuitionistic fuzzy β-nearly compactness under several types of intuitionistic fuzzy continuous mappings.

  20. Numerical simulation of intelligent compaction technology for construction quality control.

    Science.gov (United States)

    2014-12-01

    Intelligent compaction (IC) technique is a fast-developing technology for compaction quality control and acceptance. Proof rolling using the intelligent compaction rollers after completing compaction can eectively identify : the weak spots and sig...

  1. COSMIC SHEAR MEASUREMENT USING AUTO-CONVOLVED IMAGES

    International Nuclear Information System (INIS)

    Li, Xiangchong; Zhang, Jun

    2016-01-01

    We study the possibility of using quadrupole moments of auto-convolved galaxy images to measure cosmic shear. The autoconvolution of an image corresponds to the inverse Fourier transformation of its power spectrum. The new method has the following advantages: the smearing effect due to the point-spread function (PSF) can be corrected by subtracting the quadrupole moments of the auto-convolved PSF; the centroid of the auto-convolved image is trivially identified; the systematic error due to noise can be directly removed in Fourier space; the PSF image can also contain noise, the effect of which can be similarly removed. With a large ensemble of simulated galaxy images, we show that the new method can reach a sub-percent level accuracy under general conditions, albeit with increasingly large stamp size for galaxies of less compact profiles.

  2. INVESTIGATION OF INNER SHEAR RESISTANCE OF GEOGRIDS BUILT UNDER GRANULAR PROTECTION LAYERS AND RAILWAY BALLAST

    Directory of Open Access Journals (Sweden)

    Sz. Fischer

    2015-10-01

    Full Text Available Purpose. Using adequate granular materials and layer structures in the railway super- and substructure is able to stabilise railway track geometry. For this purpose special behaviour of above materials has to be determined, e.g. inner shear resistance. Inner shear resistance of granular media with and without geogrid reinforcement in different depths is not known yet. Methodology. The author developed a special laboratory method to measure and define inner shear resistance of granular materials, it is called «multi-level shear box test». This method is adequate to determine inner shear resistance (pushing force vs. depth (distance from the «zero» surface. Two different granular materials: andesite railway ballast (31.5/63 mm and andesite railway protection layer material (0/56 mm, and seven different types of geogrids (GG1…GG7 were used during the tests. Findings. Values of inner shear resistance functions of andesite railway ballast without geogrid reinforcement and reinforced with different types of geogrids and andesite granular protection layer in function of the vertical distance from the geogrid plane were determined with multi-layer shear box tests when the material aggregation is uncompacted and compacted. Only the compacted sample was tested in case of the 0/56 mm protection layer. Cubic polynomial regression functions fitted on the mean values of the measurements are described graphically. Determination coefficients with values of R2>0.97 were resulted in all the cases of regression functions. Based on the polynomial regression functions fitted on the mean values of the test results, three increasing factors were determined in function of the distance measured from the geogrid. Increasing factor «A», «B» and «D». Originality. Multi-level shear box test, developed by the author, is certified unequivocally adequate for determining inner shear resistance of reinforced and unreinforced granular materials, e.g. railway ballast

  3. Response Of Lowland Rice To Soil Compaction

    International Nuclear Information System (INIS)

    Idawati; Haryanto

    2000-01-01

    Soil compaction, as a new tillage practice for paddy soil, is to substitute pudding in order to reduce land preparation cost. To study response of lowland rice to soil compaction, a pot experiment has been conducted which took place in the greenhouse of P3TIR-BATAN. Soil for experiment was taken from pusakanegara. Two factors (degree of soil compaction and rice variety) were combined. Degree of compaction was split into 3 levels (DI = normal; D215% more compact than normal; 30 % more compact than normal), and rice variety into 2 levels (IR64 and Atomita IV). KH 2 32 PO 4 solution was injected into the soil surrounding rice clump to test the root activity at blooming stage of rice plant. Data resulted from this experiment is presented together with additional data from some other experiments of fertilization in the research s erie to study soil compaction. Some information's from experiment results are as following. Both rice varieties tested gave the same response to soil compaction. Root activity, according to data of 32 P absorbed by plant, was not harmed by soil compaction at the degree tested in the experiment. This prediction is supported by the growth by rice observed at generative growth stage, in pot experiment as well as in field experiment, which showed that soil compaction tested did not decrease rice yield but in opposite in tended to increase the yield. In practising soil compaction in land preparation, fertilizers should be applied by deep placement to have higher increasing is rice yield

  4. Effects of sand compaction pile (SCP) driving on the strength of clay outside the improved area; Sand compaction pile no dasetsu ga jiban kairyo ikigai no nendo jiban no kyodo ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, H. [Yamaguchi University, Yamaguchi (Japan); Takahashi, S. [Ministry of Transport, Tokyo (Japan); Fujiwara, K. [Penta-Ocean Construction Co. Ltd., Tokyo (Japan); Kitayama, N. [Fukken Co. Ltd., Hiroshima (Japan)

    1998-06-21

    This paper describes effects of the disturbance by the sand compaction pile (SCP) driving operations on the shear strength of clay outside the improved area and the border of region affected by the SCP driving. About 1,400 soil specimens were taken before and after the SCP driving inside and outside the improved area during the foundation improvement at Tokuyama-Shimomatsu Port in Yamaguchi Prefecture. Soil test data of the specimens and strength characteristics of disturbed clay specimens were investigated through the laboratory experiments. The results obtained are as follows. According to the multi-directional simple shear test results, the shear strength immediately after the cyclic shear decreased in 10 to 30% compared with that before the cyclic shear. When recompaction was conducted before the cyclic shear, however, it increased in 50% compared with that before the cyclic shear. The strength of clay decreased by the SCP driving even outside the improved area. When the internal frictional angle of clay, friction coefficient of the improved boundary and driving depth of SCP were determined, it was possible to estimate an area affected by the SCP driving using a combined sliding plane. 21 refs., 18 figs.

  5. Flexural behaviour and punching shear of selfcompacting concrete ribbed slab reinforced with steel fibres

    Directory of Open Access Journals (Sweden)

    Ahmad Hazrina

    2017-01-01

    Full Text Available This paper investigates the effects of steel fibres as a replacement to the conventional reinforcement under flexural behaviour and punching shear in self-compacting (SCC ribbed slab reinforced with steel fibres. Four ribbed slabs with similar dimensions of 2.8 m length × 1.2 m width and 0.2m thickness were constructed. Two of the samples were considered as control samples (conventionally reinforced with reinforcement bars and welded mesh while another two samples were fully reinforced with 1% (80 kg/m3 volume of steel fibres incorporated to the SCC mix. For the flexural behaviour study, the ribbed slab samples were subjected to two line loads under four point bending. Meanwhile, for the punching shear analysis, the ribbed slab samples were subjected to a point load to simulate loading from the column. The analysis of the experimental results displayed that steel fibres incorporation had been found to effectively delay the first crack occurrence under both flexural and punching shear. The steel fibre replacement has been proven to be able to sustain up to 80% and 73% of the ultimate load resistance for flexural and punching shear, respectively, in comparison to conventionally reinforced ribbed slab structure. The visual observation carried out during the experiment exhibited similar failure mode for both steel fibre reinforced and control samples. This was observed for both flexural and punching shear samples. Overall, it can be concluded that the steel fibres had displayed a promising potential to effectively replace the conventional reinforcements.

  6. Laboratory Characterization of Mechanical and Permeability Properties of Dynamically Compacted Crushed Salt

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, F.D.; Mellegard, K.D.; Pfeifle, T.W.

    1999-02-01

    The U. S. Department of Energy plans to dispose of transuranic wastes at the Waste Isolation Pilot Plant (WIPP), a geologic repository located at a depth of about 655 meters. The WIPP underground facility is located in the bedded salt of the Salado Formation. Access to the facility is provided through vertical shafts, which will be sealed after decommissioning to limit the release of hazardous waste from the repository and to limit flow into the facility. Because limited data are available to characterize the properties of dynamically compacted crushed salt, Sandia National Laboratories authorized RE/SPEC to perform additional tests on specimens of dynamically compacted crushed salt. These included shear consolidation creep, permeability, and constant strain-rate triaxial compression tests. A limited number of samples obtained from the large compacted mass were available for use in the testing program. Thus, additional tests were performed on samples that were prepared on a smaller scale device in the RE/SPEC laboratory using a dynamic-compaction procedure based on the full-scale construction technique. The laboratory results were expected to (1) illuminate the phenomenology of crushed-salt deformation behavior and (2) add test results to a small preexisting database for purposes of estimating parameters in a crushed-salt constitutive model. The candidate constitutive model for dynamically compacted crushed salt was refined in parallel with this laboratory testing.

  7. Portable compact multifunction IR calibrator

    International Nuclear Information System (INIS)

    Wyatt, C.L.; Jacobsen, L.; Steed, A.

    1988-01-01

    A compact portable multifunction calibrator designed for future sensor systems is described which enables a linearity calibration for all detectors simultaneously using a near small-area source, a high-resolution mapping of the focal plane with 10 microrad setability and with a blur of less than 100 microrad, system spectral response calibration (radiometer) using a Michelson interferometer source, relative spectral response (spectrometer) using high-temperature external commercial blackbody simulators, and an absolute calibration using an internal low-temperature extended-area source. 5 references

  8. Simplified compact containment BWR plant

    International Nuclear Information System (INIS)

    Heki, H.; Nakamaru, M.; Tsutagawa, M.; Hiraiwa, K.; Arai, K.; Hida, T.

    2004-01-01

    The reactor concept considered in this paper has a small power output, a compact containment and a simplified BWR configuration with comprehensive safety features. The Compact Containment Boiling Water Reactor (CCR), which is being developed with matured BWR technologies together with innovative systems/components, is expected to prove attractive in the world energy markets due to its flexibility in regard to both energy demands and site conditions, its high potential for reducing investment risk and its safety features facilitating public acceptance. The flexibility is achieved by CCR's small power output of 300 MWe class and capability of long operating cycle (refueling intervals). CCR is expected to be attractive from view point of investment due to its simplification/innovation in design such as natural circulation core cooling with the bottom located short core, internal upper entry control rod drives (CRDs) with ring-type dryers and simplified ECCS system with high pressure containment concept. The natural circulation core eliminates recirculation pumps and the maintenance of such pumps. The internal upper entry CRDs reduce the height of the reactor vessel (RPV) and consequently reduce the height of the primary containment vessel (PCV). The safety features mainly consist of large water inventory above the core without large penetration below the top of the core, passive cooling system by isolation condenser (IC), passive auto catalytic recombiner and in-vessel retention (IVR) capability. The large inventory increases the system response time in the case of design-base accidents, including loss of coolant accidents. The IC suppresses PCV pressure by steam condensation without any AC power. The recombiner decreases hydrogen concentration in the PCV in the case of a severe accident. Cooling the molten core inside the RPV if the core should be damaged by loss of core coolability could attain the IVR. The feasibility of CCR safety system has been confirmed by LOCA

  9. Compact objects in Horndeski gravity

    Science.gov (United States)

    Silva, Hector O.; Maselli, Andrea; Minamitsuji, Masato; Berti, Emanuele

    2016-04-01

    Horndeski gravity holds a special position as the most general extension of Einstein’s theory of general relativity (GR) with a single scalar degree of freedom and second-order field equations. Because of these features, Horndeski gravity is an attractive phenomenological playground to investigate the consequences of modifications of GR in cosmology and astrophysics. We present a review of the progress made so far in the study of compact objects (black holes (BHs) and neutron stars (NSs)) within Horndeski gravity. In particular, we review our recent work on slowly rotating BHs and present some new results on slowly rotating NSs.

  10. Matter in compact binary mergers

    Science.gov (United States)

    Read, Jocelyn; LIGO Scientific Collaboration, Virgo Scientific Collaboration

    2018-01-01

    Mergers of binary neutron stars or neutron-star/black-hole systems are promising targets for gravitational-wave detection. The dynamics of merging compact objects, and thus their gravitational-wave signatures, are primarily determined by the mass and spin of the components. However, the presence of matter can make an imprint on the final orbits and merger of a binary system. I will outline efforts to understand the impact of neutron-star matter on gravitational waves, using both theoretical and computational input, so that gravitational-wave observations can be used to measure the properties of source systems with neutron-star components.

  11. Self-compacting concrete (SCC)

    DEFF Research Database (Denmark)

    Geiker, Mette Rica

    2008-01-01

    In many aspects Self-Compacting Concrete (SCC, “Self-Consolidating Concrete” in North America) can be considered the concrete of the future. SCC is a family of tailored concretes with special engineered properties in the fresh state. SCC flows into the formwork and around even complicated...... reinforcement arrangements under its own weight. Thus, SCC is not vibrated like conventional concrete. This drastically improves the working environment during construction, the productivity, and potentially improves the homogeneity and quality of the concrete. In addition SCC provides larger architectural...

  12. Compact Radiometers Expand Climate Knowledge

    Science.gov (United States)

    2010-01-01

    To gain a better understanding of Earth's water, energy, and carbon cycles, NASA plans to embark on the Soil Moisture Active and Passive mission in 2015. To prepare, Goddard Space Flight Center provided Small Business Innovation Research (SBIR) funding to ProSensing Inc., of Amherst, Massachusetts, to develop a compact ultrastable radiometer for sea surface salinity and soil moisture mapping. ProSensing incorporated small, low-cost, high-performance elements into just a few circuit boards and now offers two lightweight radiometers commercially. Government research agencies, university research groups, and large corporations around the world are using the devices for mapping soil moisture, ocean salinity, and wind speed.

  13. The dynamics of a shear band

    Science.gov (United States)

    Giarola, Diana; Capuani, Domenico; Bigoni, Davide

    2018-03-01

    A shear band of finite length, formed inside a ductile material at a certain stage of a continued homogeneous strain, provides a dynamic perturbation to an incident wave field, which strongly influences the dynamics of the material and affects its path to failure. The investigation of this perturbation is presented for a ductile metal, with reference to the incremental mechanics of a material obeying the J2-deformation theory of plasticity (a special form of prestressed, elastic, anisotropic, and incompressible solid). The treatment originates from the derivation of integral representations relating the incremental mechanical fields at every point of the medium to the incremental displacement jump across the shear band faces, generated by an impinging wave. The boundary integral equations (under the plane strain assumption) are numerically approached through a collocation technique, which keeps into account the singularity at the shear band tips and permits the analysis of an incident wave impinging a shear band. It is shown that the presence of the shear band induces a resonance, visible in the incremental displacement field and in the stress intensity factor at the shear band tips, which promotes shear band growth. Moreover, the waves scattered by the shear band are shown to generate a fine texture of vibrations, parallel to the shear band line and propagating at a long distance from it, but leaving a sort of conical shadow zone, which emanates from the tips of the shear band.

  14. Separation performance and interfacial properties of nanocomposite reverse osmosis membranes

    KAUST Repository

    Pendergast, MaryTheresa M.

    2013-01-01

    Four different types of nanocomposite reverse osmosis (RO) membranes were formed by interfacial polymerization of either polyamide (PA) or zeolite A-polyamide nanocomposite (ZA-PA) thin films over either pure polysulfone (PSf) or zeolite A-polysulfone nanocomposite (ZA-PSf) support membranes cast by wet phase inversion. All three nanocomposite membranes exhibited superior separation performance and interfacial properties relative to hand-cast TFC analogs including: (1) smoother, more hydrophilic surfaces (2) higher water permeability and salt rejection, and (3) improved resistance to physical compaction. Less compaction occurred for membranes with nanoparticles embedded in interfacially polymerized coating films, which adds further proof that flux decline associated with physical compaction is influenced by coating film properties in addition to support membrane properties. The new classes of nanocomposite membrane materials continue to offer promise of further improved RO membranes for use in desalination and advanced water purification. © 2011 Elsevier B.V.

  15. Nucleation in Sheared Granular Matter

    Science.gov (United States)

    Rietz, Frank; Radin, Charles; Swinney, Harry L.; Schröter, Matthias

    2018-02-01

    We present an experiment on crystallization of packings of macroscopic granular spheres. This system is often considered to be a model for thermally driven atomic or colloidal systems. Cyclically shearing a packing of frictional spheres, we observe a first order phase transition from a disordered to an ordered state. The ordered state consists of crystallites of mixed fcc and hcp symmetry that coexist with the amorphous bulk. The transition, initiated by homogeneous nucleation, overcomes a barrier at 64.5% volume fraction. Nucleation consists predominantly of the dissolving of small nuclei and the growth of nuclei that have reached a critical size of about ten spheres.

  16. Nucleation in Sheared Granular Matter.

    Science.gov (United States)

    Rietz, Frank; Radin, Charles; Swinney, Harry L; Schröter, Matthias

    2018-02-02

    We present an experiment on crystallization of packings of macroscopic granular spheres. This system is often considered to be a model for thermally driven atomic or colloidal systems. Cyclically shearing a packing of frictional spheres, we observe a first order phase transition from a disordered to an ordered state. The ordered state consists of crystallites of mixed fcc and hcp symmetry that coexist with the amorphous bulk. The transition, initiated by homogeneous nucleation, overcomes a barrier at 64.5% volume fraction. Nucleation consists predominantly of the dissolving of small nuclei and the growth of nuclei that have reached a critical size of about ten spheres.

  17. Relative viscosity of emulsions in simple shear flow: Temperature, shear rate, and interfacial tension dependence

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Se Bin; Lee, Joon Sang [Dept. of Mechanical Engineering, Yonsei Unversity, Seoul (Korea, Republic of)

    2015-08-15

    We simulate an emulsion system under simple shear rates to analyze its rheological characteristics using the lattice Boltzmann method (LBM). We calculate the relative viscosity of an emulsion under a simple shear flow along with changes in temperature, shear rate, and surfactant concentration. The relative viscosity of emulsions decreased with an increase in temperature. We observed the shear-thinning phenomena, which is responsible for the inverse proportion between the shear rate and viscosity. An increase in the interfacial tension caused a decrease in the relative viscosity of the decane-in-water emulsion because the increased deformation caused by the decreased interfacial tension significantly influenced the wall shear stress.

  18. Brittle to ductile transition in a model of sheared granular materials

    Science.gov (United States)

    Ma, X.; Elbanna, A. E.

    2016-12-01

    Understanding the fundamental mechanisms of deformation and failure in sheared fault gouge is critical for the development of physics-based earthquake rupture simulations that are becoming an essential ingredient in next generation hazard and risk models. To that end, we use the shear transformation zone (STZ) theory, a non-equilibrium statistical thermodynamics framework to describe viscoplastic deformation and localization in gouge materials as a first step towards developing multiscale models for earthquake source processes that are informed by high-resolution fault zone physics. The primary ingredient of the STZ theory is that inelastic deformation occurs at rare and local non-interacting soft zones known as the shear transformation zones. The larger the number of these STZs the more disordered (the more loose) the layer is. We will describe an implementation of this theory in a 2D/3D finite element framework, accounting for finite deformation, under both axial and shear loading and for dry and saturated conditions. We examine conditions under which a localized shear band may form and show that the initial value of disorder (or the initial porosity) plays an important role. In particular, our simulations suggest that if the material is more compact initially, the behavior is more brittle and the plastic deformation localizes with generating large strength drop. On the other hand, an initially loose material will show a more ductile response and the plastic deformations will be distributed more broadly. We will further show that incorporation of pore fluids alters the localization pattern and changes the stress slip response due to coupling between gouge volume changes (compaction and dilation) and pore pressure build up. We validate the model predictions by comparing them to available experimental observations on strain localization and fault gouge strength evolution. Finally, we discuss the implications of our model for gouge friction and dynamic weakening.

  19. Compact Visualisation of Video Summaries

    Directory of Open Access Journals (Sweden)

    Janko Ćalić

    2007-01-01

    Full Text Available This paper presents a system for compact and intuitive video summarisation aimed at both high-end professional production environments and small-screen portable devices. To represent large amounts of information in the form of a video key-frame summary, this paper studies the narrative grammar of comics, and using its universal and intuitive rules, lays out visual summaries in an efficient and user-centered way. In addition, the system exploits visual attention modelling and rapid serial visual presentation to generate highly compact summaries on mobile devices. A robust real-time algorithm for key-frame extraction is presented. The system ranks importance of key-frame sizes in the final layout by balancing the dominant visual representability and discovery of unanticipated content utilising a specific cost function and an unsupervised robust spectral clustering technique. A final layout is created using an optimisation algorithm based on dynamic programming. Algorithm efficiency and robustness are demonstrated by comparing the results with a manually labelled ground truth and with optimal panelling solutions.

  20. Geotechnical Aspects of Explosive Compaction

    Directory of Open Access Journals (Sweden)

    Mahdi Shakeran

    2016-01-01

    Full Text Available Explosive Compaction (EC is the ground modification technique whereby the energy released from setting off explosives in subsoil inducing artificial earthquake effects, which compact the soil layers. The efficiency of EC predominantly depends on the soil profile, grain size distribution, initial status, and the intensity of energy applied to the soil. In this paper, in order to investigate the geotechnical aspects, which play an important role in performance of EC, a database has been compiled from thirteen-field tests or construction sites around the world, where EC has been successfully applied for modifying soil. This research focuses on evaluation of grain size distribution and initial stability status of deposits besides changes of soil penetration resistance due to EC. Results indicated suitable EC performance for unstable and liquefiable deposits having particle sizes ranging from gravel to silty sand with less than 40% silt content and less than 10% clay content. However, EC is most effective in fine-to-medium sands with a fine content less than 5% and hydraulically deposited with initial relative density ranging from 30% to 60%. Moreover, it has been observed that EC can be an effective method to improve the density, stability, and resistance of the target soils.

  1. Spectrometers for compact neutron sources

    Science.gov (United States)

    Voigt, J.; Böhm, S.; Dabruck, J. P.; Rücker, U.; Gutberlet, T.; Brückel, T.

    2018-03-01

    We discuss the potential for neutron spectrometers at novel accelerator driven compact neutron sources. Such a High Brilliance Source (HBS) relies on low energy nuclear reactions, which enable cryogenic moderators in very close proximity to the target and neutron optics at comparably short distances from the moderator compared to existing sources. While the first effect aims at increasing the phase space density of a moderator, the second allows the extraction of a large phase space volume, which is typically requested for spectrometer applications. We find that competitive spectrometers can be realized if (a) the neutron production rate can be synchronized with the experiment repetition rate and (b) the emission characteristics of the moderator can be matched to the phase space requirements of the experiment. MCNP simulations for protons or deuterons on a Beryllium target with a suitable target/moderator design yield a source brightness, from which we calculate the sample fluxes by phase space considerations for different types of spectrometers. These match closely the figures of todays spectrometers at medium flux sources. Hence we conclude that compact neutron sources might be a viable option for next generation neutron sources.

  2. High flux compact neutron generators

    International Nuclear Information System (INIS)

    Reijonen, J.; Lou, T.-P.; Tolmachoff, B.; Leung, K.-N.; Verbeke, J.; Vujic, J.

    2001-01-01

    Compact high flux neutron generators are developed at the Lawrence Berkeley National Laboratory. The neutron production is based on D-D or D-T reaction. The deuterium or tritium ions are produced from plasma using either a 2 MHz or 13.56 MHz radio frequency (RF) discharge. RF-discharge yields high fraction of atomic species in the beam which enables higher neutron output. In the first tube design, the ion beam is formed using a multiple hole accelerator column. The beam is accelerated to energy of 80 keV by means of a three-electrode extraction system. The ion beam then impinges on a titanium target where either the 2.4 MeV D-D or 14 MeV D-T neutrons are generated. The MCNP computation code has predicted a neutron flux of ∼10 11 n/s for the D-D reaction at beam intensity of 1.5 A at 150 kV. The neutron flux measurements of this tube design will be presented. Recently new compact high flux tubes are being developed which can be used for various applications. These tubes also utilize RF-discharge for plasma generation. The design of these tubes and the first measurements will be discussed in this presentation

  3. Quark matter in compact stars

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, H., E-mail: harg@cefet-rj.b [Centro Federal de Educacao Tecnologica do Rio de Janeiro, Av. Maracana 249, 20271-110, Rio de Janeiro, RJ (Brazil); Duarte, S.B., E-mail: sbd@cbpf.b [Centro Brasileiro de Pesquisas Fisicas, Rua Dr. Xavier Sigaud 150, 22290-180, Rio de Janeiro, RJ (Brazil); Oliveira, J.C.T., E-mail: jcto@cbpf.b [Departamento de Fisica, Universidade Federal de Roraima, Campus do Paricarana s/n, 69310-270, Boa Vista, RR (Brazil)

    2010-02-15

    Recently reported massive compact stars (Mapprox2M{sub o}) have provided strong constraints on the properties of the ultradense matter beyond the saturation nuclear density. Therefore, realistic quark or hybrid star models must be compatible with these observational data. Some used equations of state (EoS) describing quark matter are in general too soft and hence are not suitable to explain the stability of high compact star masses. In this work, we present the calculations of static spherically symmetric quark star structure by using an equation of state which takes into account the superconducting colour-flavour locked phase of the strange quark matter. In addition, some fundamental aspects of QCD (asymptotic freedom and confinement) are considered by means of a phenomenological description of the deconfined quark phase, the density-dependent quark mass model. We discuss the influence of the obtained quark matter equation of state on the mass-radius relationship of quark stars. Massive quark stars are found due to the stiffness of the equation of state, when reasonable values of the superconducting gap, taken as a free parameter, are used.

  4. Inelastic Compaction in High-Porosity Limestone Monitored Using Acoustic Emissions

    Science.gov (United States)

    Baud, Patrick; Schubnel, Alexandre; Heap, Michael; Rolland, Alexandra

    2017-12-01

    We performed a systematic investigation of mechanical compaction and strain localization in Saint-Maximin limestone, a quartz-rich, high-porosity (37%) limestone from France. Our new data show that the presence of a significant proportion of secondary mineral (i.e., quartz) did not impact the mechanical strength of the limestone in both the brittle faulting and cataclastic flow regimes, but that the presence of water exerted a significant weakening effect. In contrast to previously published studies on deformation in limestones, inelastic compaction in Saint-Maximin limestone was accompanied by abundant acoustic emission (AE) activity. The location of AE hypocenters during triaxial experiments revealed the presence of compaction localization. Two failure modes were identified in agreement with microstructural analysis and X-ray computed tomography imaging: compactive shear bands developed at low confinement and complex diffuse compaction bands formed at higher confinement. Microstructural observations on deformed samples suggest that the recorded AE activity associated with inelastic compaction, unusual for a porous limestone, could have been due to microcracking at the quartz grain interfaces. Similar to published data on high-porosity macroporous limestones, the crushing of calcite grains was the dominant micromechanism of inelastic compaction in Saint-Maximin limestone. New P wave velocity data show that the effect of microcracking was dominant near the yield point and resulted in a decrease in P wave velocity, while porosity reduction resulted in a significant increase in P wave velocity beyond a few percent of plastic volumetric strain. These new data highlight the complex interplay between mineralogy, rock microstructure, and strain localization in porous rocks.

  5. Microstructural description of shear-thickening suspensions

    Directory of Open Access Journals (Sweden)

    Singh Abhinendra

    2017-01-01

    Full Text Available Dynamic particle-scale numerical simulations are used to study the variation of microstructure with shear stress during shear thickening in dense non-Brownian suspensions. The microscale information is used to characterize the differences between the shear thickened (frictional and non-thickened (lubricated, frictionless states. Here, we focus on the force and contact networks and study the evolution of associated anisotropies with increase in shear stress. The force and contact networks are both more isotropic in the shear-thickened state than in non-thickened state. We also find that both force and structural anisotropies are rate independent for both low and high stress, while they are rate (or stress dependent for the intermediate stress range where the shear thickening occurs. This behavior is similar to the evolution of viscosity with increasing stress, showing a clear correlation between the microstructure and the macroscopic rheology.

  6. An algebra of reversible computation.

    Science.gov (United States)

    Wang, Yong

    2016-01-01

    We design an axiomatization for reversible computation called reversible ACP (RACP). It has four extendible modules: basic reversible processes algebra, algebra of reversible communicating processes, recursion and abstraction. Just like process algebra ACP in classical computing, RACP can be treated as an axiomatization foundation for reversible computation.

  7. Method for preparing porous metal hydride compacts

    Science.gov (United States)

    Ron, M.; Gruen, D.M.; Mendelsohn, M.H.; Sheft, I.

    1980-01-21

    A method for preparing porous metallic-matrix hydride compacts which can be repeatedly hydrided and dehydrided without disintegration. A mixture of a finely divided metal hydride and a finely divided matrix metal is contacted with a poison which prevents the metal hydride from dehydriding at room temperature and atmospheric pressure. The mixture of matrix metal and poisoned metal hydride is then compacted under pressure at room temperature to form porous metallic-matrix hydride compacts.

  8. Developments in Plasticity Approach to Shear

    DEFF Research Database (Denmark)

    Hoang, Cao Linh; Nielsen, Mogens Peter

    1999-01-01

    The paper deals with plastic methods applied to shear design of reinforced concrete beams. Emphasis is put on the recently developed crack sliding model applicable to non-shear reinforced and lightly shear reinforced beams and slabs. The model, which is an upper bound plasticity approach, takes...... into account the mechanism of crack formation followed by crack sliding. Comparisons between the model and test results are carried out. Good agreement has been found over a wide range of cases....

  9. The Effect of a Shear Flow on the Uptake of LDL and Ac-LDL by Cultured Vascular Endothelial Cells

    Science.gov (United States)

    Niwa, Koichi; Karino, Takeshi

    The effects of a shear flow on the uptake of fluorescence-labeled low-density lipoprotein (DiI-LDL), acetylated LDL (DiI-Ac-LDL), and lucifer yellow (LY; a tracer of fluid-phase endocytosis) by cultured bovine aortic ECs were studied using a rotating-disk shearing apparatus. It was found that 2hours’ exposure of ECs to a laminar shear flow that imposed ECs an area-mean shear stress of 10dynes/cm2 caused an increase in the uptake of DiI-LDL and LY. By contrast, the uptake of DiI-Ac-LDL was decreased by exposure of the ECs to a shear flow. Addition of dextran sulfate (DS), a competitive inhibitor of scavenger receptors, reversed the effect of a shear flow on the uptake of DiI-Ac-LDL, resulting in an increase by the imposition of a shear flow, while the uptake of DiI-LDL and LY remained unaffected. It was concluded that a shear flow promotes the endocytosis of DiI-LDL and LY by ECs, but suppresses the uptake of DiI-Ac-LDL by ECs by inhibiting scavenger receptor-mediated endocytosis.

  10. Risk assessment of soil compaction in Walloon Region (Belgium)

    Science.gov (United States)

    Charlotte, Rosiere; Marie-France, Destain; Jean-Claude, Verbrugge

    2010-05-01

    The proposed Soil Framework Directive COM(2006)232 requires Member States to identify areas at risk of erosion, decline in organic matter, salinisation, compaction, sealing and landslides, as well as to set up an inventory of contaminated sites. The present project aims to identify the susceptibility to compaction of soils of the Walloon Region (Belgium) and to recommend good farming practices avoiding soil compaction as far as possible. Within this scope, the concept of precompression stress (Pc) (Horn and Fleige, 2003) was used. Pc is defined as the maximum major principal stress that a soil horizon can withstand against any applied external vertical stress. If applied stress is higher than Pc, the soil enters in a plastic state, not easily reversible. For a given soil, the intensity of soil compaction is mainly due to the applied load which depends on vehicle characteristics (axle load, tyre dimensions, tyre inflation pressure, and vehicle velocity). To determine soil precompression stress, pedotransfert functions of Lebert and Horn (1991) defined at two water suctions (pF 1.8 and 2.5) were used. Parameters required by these functions were found within several databases (Aardewerk and Digital Map of Walloon Soils) and literature. The validation of Pc was performed by measuring stress-strain relationships using automatic oedometers. Stresses of 15.6, 31, 3, 62.5, 125, 250, 500 and 1000 kPa were applied for 10 min each. In this study, the compaction due to beet harvesters was considered because the axle load can exceed 10 tons and these machines are often used during wet conditions. The compaction at two depth levels was considered: 30 and 50 cm. Compaction of topsoil was not taken into account because, under conventional tillage, the plough depth is lower than 25 cm. Before and after the passage of the machines, following measurements were performed: granulometry, density, soil moisture, pF curve, Atterberg limits, ... The software Soilflex (Keller et al., 2007

  11. Soil compaction and growth of woody plants

    International Nuclear Information System (INIS)

    Kozlowski, T.T.

    1999-01-01

    Although soil compaction in the field may benefit or inhibit the growth of plants, the harmful effects are much more common. This paper emphasizes the deleterious effects of predominantly high levels of soil compaction on plant growth and yield. High levels of soil compaction are common in heavily used recreation areas, construction sites, urban areas, timber harvesting sites, fruit orchards, agroforestry systems and tree nurseries. Compaction can occur naturally by settling or slumping of soil or may be induced by tillage tools, heavy machinery, pedestrian traffic, trampling by animals and fire. Compaction typically alters soil structure and hydrology by increasing soil bulk density; breaking down soil aggregates; decreasing soil porosity, aeration and infiltration capacity; and by increasing soil strength, water runoff and soil erosion. Appreciable compaction of soil leads to physiological dysfunctions in plants. Often, but not always, reduced water absorption and leaf water deficits develop. Soil compaction also induces changes in the amounts and balances of growth hormones in plants, especially increases in abscisic acid and ethylene. Absorption of the major mineral nutrients is reduced by compaction of both surface soils and subsoils. The rate of photosynthesis of plants growing in very compacted soil is decreased by both stomatal and non-stomatal inhibition. Total photosynthesis is reduced as a result of smaller leaf areas. As soils become increasingly compacted respiration of roots shifts toward an anaerobic state. Severe soil compaction adversely influences regeneration of forest stands by inhibiting seed germination and growth of seedlings, and by inducing seedling mortality. Growth of woody plants beyond the seedling stage and yields of harvestable plant products also are greatly decreased by soil compaction because of the combined effects of high soil strength, decreased infiltration of water and poor soil aeration, all of which lead to a decreased

  12. Soil compaction and growth of woody plants

    Energy Technology Data Exchange (ETDEWEB)

    Kozlowski, T.T. [Univ. of California, Berkeley (United States). Dept. of Environmental Science, Policy and Management

    1999-07-01

    Although soil compaction in the field may benefit or inhibit the growth of plants, the harmful effects are much more common. This paper emphasizes the deleterious effects of predominantly high levels of soil compaction on plant growth and yield. High levels of soil compaction are common in heavily used recreation areas, construction sites, urban areas, timber harvesting sites, fruit orchards, agroforestry systems and tree nurseries. Compaction can occur naturally by settling or slumping of soil or may be induced by tillage tools, heavy machinery, pedestrian traffic, trampling by animals and fire. Compaction typically alters soil structure and hydrology by increasing soil bulk density; breaking down soil aggregates; decreasing soil porosity, aeration and infiltration capacity; and by increasing soil strength, water runoff and soil erosion. Appreciable compaction of soil leads to physiological dysfunctions in plants. Often, but not always, reduced water absorption and leaf water deficits develop. Soil compaction also induces changes in the amounts and balances of growth hormones in plants, especially increases in abscisic acid and ethylene. Absorption of the major mineral nutrients is reduced by compaction of both surface soils and subsoils. The rate of photosynthesis of plants growing in very compacted soil is decreased by both stomatal and non-stomatal inhibition. Total photosynthesis is reduced as a result of smaller leaf areas. As soils become increasingly compacted respiration of roots shifts toward an anaerobic state. Severe soil compaction adversely influences regeneration of forest stands by inhibiting seed germination and growth of seedlings, and by inducing seedling mortality. Growth of woody plants beyond the seedling stage and yields of harvestable plant products also are greatly decreased by soil compaction because of the combined effects of high soil strength, decreased infiltration of water and poor soil aeration, all of which lead to a decreased

  13. Instability of periodic MHD shear flows

    International Nuclear Information System (INIS)

    Zaqarashvili, T.V.; Oliver, R.; Ballester, J.L.; Belvedere, G.

    2004-01-01

    The stability of periodic MHD shear flows generated by an external transversal periodic force in magnetized plasma is studied. It is shown that the temporal behaviour of magnetosonic wave spatial Fourier harmonics in such flows is governed by Mathieu equation. Consequently the harmonics with the half frequency of the shear flows grow exponentially in time. Therefore the periodic shear motions are unstable to the perturbations of compressible magnetosonic waves. The motions represent the kinetic part of the transversal oscillation in magnetized plasma. Therefore due to the instability of periodic shear motions, the transversal oscillations may quickly be damped, so transferring their energy to compressible magnetosonic perturbations

  14. Shear flow generation due to electromagnetic instabilities

    International Nuclear Information System (INIS)

    Wakatani, M.; Sato, M.; Hamaguchi, S.; Miyato, N.

    2003-01-01

    Shear flow is the most important ingredient governing nonlinear behavior of many types of plasma instability. Electromagnetic effects on shear flow generation have been studied for an electro- magnetic drift wave called resistive drift-Alfven mode (RDAM) and a global MHD mode called resistive wall mode (RWM). For RDAM it is found that the generated shear flow stabilizes the dominant modes; however, other modes are destabilized. For RWM Maxwell stress due to magnetic fluctuations has a tendency to suppress the poloidal flow near the plasma surface, which gives almost same saturation level, since the shear flow stabilization disappears. (author)

  15. Low-rise shear wall failure modes

    International Nuclear Information System (INIS)

    Farrar, C.R.; Hashimoto, P.S.; Reed, J.W.

    1991-01-01

    A summary of the data that are available concerning the structural response of low-rise shear walls is presented. This data will be used to address two failure modes associated with the shear wall structures. First, data concerning the seismic capacity of the shear walls with emphasis on excessive deformations that can cause equipment failure are examined. Second, data concerning the dynamic properties of shear walls (stiffness and damping) that are necessary to compute the seismic inputs to attached equipment are summarized. This case addresses the failure of equipment when the structure remains functional. 23 refs

  16. Tubal Ligation Reversal

    Science.gov (United States)

    ... and other factors. Success rates may be as high as 80 percent or as low as near 40 percent depending on your circumstances. Tubal ligation reversal is abdominal surgery, which carries a risk of infection, bleeding and ...

  17. Sex reversal in vertebrates

    OpenAIRE

    2016-01-01

    This special topic issue of Sexual Development gives an overview of sex reversal in vertebrates, from fishes naturally changing their sex, to rodents escaping the mammalian SRY-determining system. It offers eight up-to-date reviews on specific subjects in sex reversal, considering fishes, amphibians, reptiles, birds, marsupials, and placental mammals, including humans. The broad scope of represented animals makes this ideal for students and researchers, especially those interested in the...

  18. Continuous shear - a method for studying material elements passing a stationary shear plane

    DEFF Research Database (Denmark)

    Lindegren, Maria; Wiwe, Birgitte; Wanheim, Tarras

    2003-01-01

    Traditionally, material response to shear deformation has been studied with methods where the shear is gradually increasing from zero to the final value over a certain fixed deformation zone, e.g. in the well-known torsion test of a tube with a defined shear zone established by a machined...... circumferential groove. Normally shear in metal forming processes is of another nature, namely where the material elements move through a stationary shear zone, often of small width. In this paper a method enabling the simulation of this situation is presented. A tool for continuous shear has beeen manufactured...... and tested with AlMgSil and copper. The sheared material has thereafter been tested n plane strain compression with different orientation concerning the angle between the shear plane and the compression direction....

  19. What do reversible programs compute?

    DEFF Research Database (Denmark)

    Axelsen, Holger Bock; Glück, Robert

    2011-01-01

    transformation, program transformations such as inversion, and general static prediction of program properties. Historically, work on reversible computing has focussed on reversible simulations of irreversible computations. Here, we take the viewpoint that the property of reversibility itself should...

  20. A biaxial method for inplane shear testing. [shear strain in composite materials

    Science.gov (United States)

    Bush, H. G.; Weller, T.

    1978-01-01

    A biaxial method for performing inplane shear tests of materials using a shear frame is described. Aluminum plate and sandwich specimens were used to characterize the uniformity of shear strain imparted by the biaxial method of loading as opposed to the uniaxial method. The inplane stiffening effect of aluminum honeycomb core was determined. Test results for (+ or - 45) graphite-epoxy laminate are presented. Some theoretical considerations of subjecting an anisotropic material to a uniform shear deformation are discussed.

  1. Rail Shear and Short Beam Shear Properties of Various 3-Dimensional (3-D) Woven Composites

    Science.gov (United States)

    2016-01-01

    14 Fig. 9 Load vs. deflection curves from short beam shear experiments ..........17 Fig. 10 Short beam shear specimens cracking in tension on...Walter et al.17 Fig. 10 Short beam shear specimens cracking in tension on the bottom of the specimen Approved for public release; distribution is...unlimited. 19 Fig. 11 Short beam shear specimens cracking as viewed from the side While the 2-D base composite produced a widespread

  2. Shear thinning behaviors in magmas

    Science.gov (United States)

    Vetere, F. P.; Cassetta, M.; Perugini, D.

    2017-12-01

    Studies on magma rheology are of fundamental importance to understanding magmatic processes from depth to surface. Since viscosity is one of the most important parameter controlling eruption mechanisms, as well as lava flow emplacement, a comprehensive knowledge on the evolution of magma viscosities during crystallization is required. We present new viscosity data on partly crystalized basalt, andesite and analogue lavas comparable to those erupted on Mercury's northern volcanic plains. High-temperature viscosity measurements were performed using a rotational Anton Paar RheolabQC viscometer head at the PVRG labs, in Perugia (Italy) (http://pvrg.unipg.it). The relative proportion of phases in each experimental run were determined by image analysis on BS-SEM images at different magnifications; phases are glasses, clinopyroxene, spinel, plagioclase for the basalt, plagioclase and spinel for the andesite and pure enstatite and clinopyroxenes, for the analogue Mercury's composition. Glass and crystalline fractions determined by image analysis well correlate with compositions of residual melts. In order to constrain the viscosity (η) variations as a function of crystallinity, shear rate (γ) was varied from 0.1 to 5 s-1. Viscosity vs. time at constant temperature shows a typical S-shape curve. In particular, for basaltic composition η vary from 3.1-3.8 Pa s [log η] at 1493 K and crystallinity of 19 area % as γ vary from 1.0 to 0.1 s-1; the andesite viscosity evolution is 3.2 and 3.7 Pa s [log η] as γ varies from 1 to 0.1 at 1493 K and crystal content of 17 area %; finally, Mercury's analogue composition was investigated at different temperature ranging from 1533 to 1502 K (Vetere et al., 2017). Results, for γ = 0.1, 1.0 and 5.0 s-1, show viscosity variation between 2.7-4.0, 2.5-3.4 and 2.0-3.0 [log η inPa s] respectively while crystallinity vary from 9 to 27 (area %). As viscosity decreases as shear rate increases, these data points to a shear thinning behaviour

  3. (U) Influence of Compaction Model Form on Planar and Cylindrical Compaction Geometries

    Energy Technology Data Exchange (ETDEWEB)

    Fredenburg, David A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Carney, Theodore Clayton [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Fichtl, Christopher Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ramsey, Scott D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2018-01-05

    The dynamic compaction response of CeO2 is examined within the frameworks of the Ramp and P-a compaction models. Hydrocode calculations simulating the dynamic response of CeO2 at several distinct pressures within the compaction region are investigated in both planar and cylindrically convergent geometries. Findings suggest additional validation of the compaction models is warranted under complex loading configurations.

  4. Compact Microwave Fourier Spectrum Analyzer

    Science.gov (United States)

    Savchenkov, Anatoliy; Matsko, Andrey; Strekalov, Dmitry

    2009-01-01

    A compact photonic microwave Fourier spectrum analyzer [a Fourier-transform microwave spectrometer, (FTMWS)] with no moving parts has been proposed for use in remote sensing of weak, natural microwave emissions from the surfaces and atmospheres of planets to enable remote analysis and determination of chemical composition and abundances of critical molecular constituents in space. The instrument is based on a Bessel beam (light modes with non-zero angular momenta) fiber-optic elements. It features low power consumption, low mass, and high resolution, without a need for any cryogenics, beyond what is achievable by the current state-of-the-art in space instruments. The instrument can also be used in a wide-band scatterometer mode in active radar systems.

  5. A Compact UWB Diversity Antenna

    Directory of Open Access Journals (Sweden)

    Hui Zhao

    2014-01-01

    Full Text Available A compact printed ultrawideband (UWB diversity antenna with a size of 30 mm × 36 mm operating at a frequency range of 3.1–10.6 GHz is proposed. The antenna is composed of two semielliptical monopoles fed by two microstrip lines. Two semicircular slots, two rectangular slots, and one stub are introduced in the ground plane to adjust the impedance bandwidth of the antenna and improve the isolation between two feeding ports. The simulated and measured results show that impedance bandwidth of the proposed antenna can cover the whole UWB band with a good isolation of < −15 dB. The radiation patterns, peak antenna gain, and envelope correlation coefficient are also measured and discussed. The measured results show that the proposed antenna can be a good candidate for some portable MIMO/diversity UWB applications.

  6. Spiral Inflector For Compact Cyclotron

    CERN Document Server

    Karamysheva, G A

    2004-01-01

    Compact cyclotron for explosives detection by nuclear resonance absorption of γ-rays in nitrogen is under development [1] Cyclotron will be equipped with the external ion source. The injection system consists of a double-drift beam bunching system, a spiral inflector, beam diagnostics, focusing and adjustment elements [2]. The spiral inflector for ion bending from axial to median plane is used. Computer model of spiral inflector for the Customs cyclotron is developed. 3D electrostatic field calculations of the designed inflector are performed. Calculated electric field map and magnetic field map of the cyclotron [3] are used for beam dynamic simulations. Numeric simulations are carried out for 500 particles using code for calculation of particle dynamics by integration of differential equations in Cartesian coordinate system written in MATLAB. Direct Coulomb particle-to-particle method is used to take into account space-charge effects.

  7. Experimental studies of compact toroids

    International Nuclear Information System (INIS)

    1991-01-01

    The Berkeley Compact Toroid Experiment (BCTX) device is a plasma device with a Marshall-gun generated, low aspect ratio toroidal plasma. The device is capable of producing spheromak-type discharges and may, with some modification, produce low-aspect ratio tokamak configurations. A unique aspect of this experimenal devie is its large lower hybrid (LH) heating system, which consists of two 450MHz klystron tubes generating 20 megawatts each into a brambilla-type launching structure. Successful operation with one klystron at virtually full power (18 MW) has been accomplished with 110 μs pulse length. A second klystron is currently installed in its socket and magnet but has not been added to the RF drive system. This report describes current activities and accomplishments and describes the anticipated results of next year's activity

  8. Compact Digital High Voltage Charger

    CERN Document Server

    Li, Ge

    2005-01-01

    The operation of classical resonant circuit developed for the pulse energizing is investigated. The HV pulse or generator is very compact by a soft switching circuit made up of IGBT working at over 30 kHZ. The frequencies of macro pulses andμpulses can be arbitrarily tuned below resonant frequency to digitalize the HV pulse power. Theμpulses can also be connected by filter circuit to get the HVDC power. The circuit topology is given and its novel control logic is analyzed by flowchart. The circuit is part of a system consisting of a AC or DC LV power supply, a pulse transformer, the pulse generator implemented by LV capacitor and leakage inductance of the transformer, a HV DC or pulse power supply and the charged HV capacitor of the modulators.

  9. Quasistatic evolution of compact toroids

    International Nuclear Information System (INIS)

    Sgro, A.G.; Spencer, R.L.; Lilliequist, C.

    1981-01-01

    Some results are presented of simulations of the post formation evolution of compact toroids. The simulations were performed with a 1-1/2 D transport code. Such a code makes explicit use of the fact that the shapes of the flux surfaces in the plasma change much more slowly than do the profiles of the physical variables across the flux surfaces. Consequently, assuming that the thermodynamic variables are always equilibrated on a flux surface, one may calculate the time evolution of these profiles as a function of a single variable that labels the flux surfaces. Occasionally, during the calculation these profiles are used to invert the equilibrium equation to update the shapes of the flux surfaces. In turn, these shapes imply certain geometric cofficients, such as A = 2 >, which contain the geometric information required by the 1-D equations

  10. Optimal shapes of compact strings

    International Nuclear Information System (INIS)

    Maritan, A.; Micheletti, C.; Trovato, A.; Banavar, J.R.

    2000-07-01

    Optimal geometrical arrangements, such as the stacking of atoms, are of relevance in diverse disciplines. A classic problem is the determination of the optimal arrangement of spheres in three dimensions in order to achieve the highest packing fraction; only recently has it been proved that the answer for infinite systems is a face-centred-cubic lattice. This simply stated problem has had a profound impact in many areas, ranging from the crystallization and melting of atomic systems, to optimal packing of objects and subdivision of space. Here we study an analogous problem-that of determining the optimal shapes of closely packed compact strings. This problem is a mathematical idealization of situations commonly encountered in biology, chemistry and physics, involving the optimal structure of folded polymeric chains. We find that, in cases where boundary effects are not dominant, helices with a particular pitch-radius ratio are selected. Interestingly, the same geometry is observed in helices in naturally-occurring proteins. (author)

  11. On thermodynamic and microscopic reversibility

    International Nuclear Information System (INIS)

    Crooks, Gavin E

    2011-01-01

    The word 'reversible' has two (apparently) distinct applications in statistical thermodynamics. A thermodynamically reversible process indicates an experimental protocol for which the entropy change is zero, whereas the principle of microscopic reversibility asserts that the probability of any trajectory of a system through phase space equals that of the time reversed trajectory. However, these two terms are actually synonymous: a thermodynamically reversible process is microscopically reversible, and vice versa

  12. General Relativity&Compact Stars

    Energy Technology Data Exchange (ETDEWEB)

    Glendenning, Norman K.

    2005-08-16

    Compact stars--broadly grouped as neutron stars and white dwarfs--are the ashes of luminous stars. One or the other is the fate that awaits the cores of most stars after a lifetime of tens to thousands of millions of years. Whichever of these objects is formed at the end of the life of a particular luminous star, the compact object will live in many respects unchanged from the state in which it was formed. Neutron stars themselves can take several forms--hyperon, hybrid, or strange quark star. Likewise white dwarfs take different forms though only in the dominant nuclear species. A black hole is probably the fate of the most massive stars, an inaccessible region of spacetime into which the entire star, ashes and all, falls at the end of the luminous phase. Neutron stars are the smallest, densest stars known. Like all stars, neutron stars rotate--some as many as a few hundred times a second. A star rotating at such a rate will experience an enormous centrifugal force that must be balanced by gravity or else it will be ripped apart. The balance of the two forces informs us of the lower limit on the stellar density. Neutron stars are 10{sup 14} times denser than Earth. Some neutron stars are in binary orbit with a companion. Application of orbital mechanics allows an assessment of masses in some cases. The mass of a neutron star is typically 1.5 solar masses. They can therefore infer their radii: about ten kilometers. Into such a small object, the entire mass of our sun and more, is compressed.

  13. Compact autonomous navigation system (CANS)

    Science.gov (United States)

    Hao, Y. C.; Ying, L.; Xiong, K.; Cheng, H. Y.; Qiao, G. D.

    2017-11-01

    Autonomous navigation of Satellite and constellation has series of benefits, such as to reduce operation cost and ground station workload, to avoid the event of crises of war and natural disaster, to increase spacecraft autonomy, and so on. Autonomous navigation satellite is independent of ground station support. Many systems are developed for autonomous navigation of satellite in the past 20 years. Along them American MANS (Microcosm Autonomous Navigation System) [1] of Microcosm Inc. and ERADS [2] [3] (Earth Reference Attitude Determination System) of Honeywell Inc. are well known. The systems anticipate a series of good features of autonomous navigation and aim low cost, integrated structure, low power consumption and compact layout. The ERADS is an integrated small 3-axis attitude sensor system with low cost and small volume. It has the Earth center measurement accuracy higher than the common IR sensor because the detected ultraviolet radiation zone of the atmosphere has a brightness gradient larger than that of the IR zone. But the ERADS is still a complex system because it has to eliminate many problems such as making of the sapphire sphere lens, birefringence effect of sapphire, high precision image transfer optical fiber flattener, ultraviolet intensifier noise, and so on. The marginal sphere FOV of the sphere lens of the ERADS is used to star imaging that may be bring some disadvantages., i.e. , the image energy and attitude measurements accuracy may be reduced due to the tilt image acceptance end of the fiber flattener in the FOV. Besides Japan, Germany and Russia developed visible earth sensor for GEO [4] [5]. Do we have a way to develop a cheaper/easier and more accurate autonomous navigation system that can be used to all LEO spacecraft, especially, to LEO small and micro satellites? To return this problem we provide a new type of the system—CANS (Compact Autonomous Navigation System) [6].

  14. General Relativity and Compact Stars

    International Nuclear Information System (INIS)

    Glendenning, Norman K.

    2005-01-01

    Compact stars--broadly grouped as neutron stars and white dwarfs--are the ashes of luminous stars. One or the other is the fate that awaits the cores of most stars after a lifetime of tens to thousands of millions of years. Whichever of these objects is formed at the end of the life of a particular luminous star, the compact object will live in many respects unchanged from the state in which it was formed. Neutron stars themselves can take several forms--hyperon, hybrid, or strange quark star. Likewise white dwarfs take different forms though only in the dominant nuclear species. A black hole is probably the fate of the most massive stars, an inaccessible region of spacetime into which the entire star, ashes and all, falls at the end of the luminous phase. Neutron stars are the smallest, densest stars known. Like all stars, neutron stars rotate--some as many as a few hundred times a second. A star rotating at such a rate will experience an enormous centrifugal force that must be balanced by gravity or else it will be ripped apart. The balance of the two forces informs us of the lower limit on the stellar density. Neutron stars are 10 14 times denser than Earth. Some neutron stars are in binary orbit with a companion. Application of orbital mechanics allows an assessment of masses in some cases. The mass of a neutron star is typically 1.5 solar masses. They can therefore infer their radii: about ten kilometers. Into such a small object, the entire mass of our sun and more, is compressed

  15. Punching shear capacity of reinforced concrete slabs with headed shear studs

    DEFF Research Database (Denmark)

    Hoang, Linh Cao; Pop, Anamaria

    2015-01-01

    . To design shear reinforcement in slabs, on the other hand, the engineer must settle for an empirical equation. The aim of the study reported is to demonstrate that it is possible in a simple manner to design shear reinforcement in slabs based on the same rigid-plasticity foundation as for beam shear design...

  16. Preliminary reactor implications of compact tori: how small is compact

    International Nuclear Information System (INIS)

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

    1979-01-01

    The application of simplified but realistic engineering constraints to the special class of wall-stabilized field-reversed theta pinch configurations leads to reactor systems that may be as small as approx. 30 m in length and generating a total thermal power of the order of 500 MWt. Decreased size and power for a given ntau/sub B/ will be accompanied by decreased performance indicators, as reflected in this study by I/sub w/ and the allowable ΔT. It should be noted that this analysis is based upon fixing the duty factor, f/sub l/ = tau/sub s//tau/sub I/

  17. Shear Viscosity from Lattice QCD

    CERN Document Server

    Mages, Simon W; Fodor, Zoltán; Schäfer, Andreas; Szabó, Kálmán

    2015-01-01

    Understanding of the transport properties of the the quark-gluon plasma is becoming increasingly important to describe current measurements at heavy ion collisions. This work reports on recent efforts to determine the shear viscosity h in the deconfined phase from lattice QCD. The main focus is on the integration of the Wilson flow in the analysis to get a better handle on the infrared behaviour of the spectral function which is relevant for transport. It is carried out at finite Wilson flow time, which eliminates the dependence on the lattice spacing. Eventually, a new continuum limit has to be carried out which sends the new regulator introduced by finite flow time to zero. Also the non-perturbative renormalization strategy applied for the energy momentum tensor is discussed. At the end some quenched results for temperatures up to 4 : 5 T c are presented

  18. A thermodynamic approach to analyze shear localization in semi-solid materials

    Science.gov (United States)

    Sheikh-Ansari, M. H.; Aghaie-Khafri, M.

    2018-03-01

    A theoretical framework of the shear localization analysis was developed for semi-solid materials taking into account a non-equilibrium relationship between viscous deformation, pressure and interfacial surface energy. Considering a shear layer model, the necessary condition of perturbation growth and subsequent shear localization was derived. The results revealed that the localization phenomenon in the semi-solid deformation strongly depends on the difference between irreversible viscous work done on pores and grains and the reversible viscous deformational work stored as the interfacial surface energy. This thermodynamic quantity indicates the possibility of a perturbation growth or decade in terms of the process parameters such as dilatancy, permeability and also the fraction of the solid skeleton.

  19. Influence of compaction on chloride ingress

    NARCIS (Netherlands)

    Zlopasa, J.

    2012-01-01

    Experiences from practice show the need for more of an understanding and optimization of the compaction process in order to design a more durable concrete structure. Local variations in compaction are very often the reason for initiation of local damage and initiation of chloride induced corrosion.

  20. Ultrasonic compaction of granular geological materials.

    Science.gov (United States)

    Feeney, Andrew; Sikaneta, Sakalima; Harkness, Patrick; Lucas, Margaret

    2017-04-01

    It has been shown that the compaction of granular materials for applications such as pharmaceutical tableting and plastic moulding can be enhanced by ultrasonic vibration of the compaction die. Ultrasonic vibrations can reduce the compaction pressure and increase particle fusion, leading to higher strength products. In this paper, the potential benefits of ultrasonics in the compaction of geological granular materials in downhole applications are explored, to gain insight into the effects of ultrasonic vibrations on compaction of different materials commonly encountered in sub-sea drilling. Ultrasonic vibrations are applied, using a resonant 20kHz compactor, to the compaction of loose sand and drill waste cuttings derived from oolitic limestone, clean quartz sandstone, and slate-phyllite. For each material, a higher strain for a given compaction pressure was achieved, with higher sample density compared to that in the case of an absence of ultrasonics. The relationships between the operational parameters of ultrasonic vibration amplitude and true strain rate are explored and shown to be dependent on the physical characteristics of the compacting materials. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Quantification of the compactibility of pharmaceutical powders

    DEFF Research Database (Denmark)

    Sonnergaard, Jørn

    2006-01-01

    The purpose of this study is to investigate and to quantify the compactibility of pharmaceutical powders by a simple linear relationship between the diametral compressive strength of tablets and the applied compaction pressure. The mechanical strength of the tablets is characterized as the crushing...

  2. The double explosive layer cylindrical compaction method

    NARCIS (Netherlands)

    Stuivinga, M.E.C.; Verbeek, H.J.; Carton, E.P.

    1999-01-01

    The standard cylindrical configuration for shock compaction is useful for the compaction of composite materials which have some plastic behavior. It can also be used to densify hard ceramics up to about 85% of the theoretical density (TMD), when low detonation velocity explosives (2-4 km s-1) are

  3. Compact Process Development at Babcock & Wilcox

    Energy Technology Data Exchange (ETDEWEB)

    Eric Shaber; Jeffrey Phillips

    2012-03-01

    Multiple process approaches have been used historically to manufacture cylindrical nuclear fuel compacts. Scale-up of fuel compacting was required for the Next Generation Nuclear Plant (NGNP) project to achieve an economically viable automated production process capable of providing a minimum of 10 compacts/minute with high production yields. In addition, the scale-up effort was required to achieve matrix density equivalent to baseline historical production processes, and allow compacting at fuel packing fractions up to 46% by volume. The scale-up approach of jet milling, fluid-bed overcoating, and hot-press compacting adopted in the U.S. Advanced Gas Reactor (AGR) Fuel Development Program involves significant paradigm shifts to capitalize on distinct advantages in simplicity, yield, and elimination of mixed waste. A series of compaction trials have been completed to optimize compaction conditions of time, temperature, and forming pressure using natural uranium oxycarbide (NUCO) fuel at packing fractions exceeding 46% by volume. Results from these trials are included. The scale-up effort is nearing completion with the process installed and operable using nuclear fuel materials. Final process testing is in progress to certify the process for manufacture of qualification test fuel compacts in 2012.

  4. Computing Decoupled Residuals for Compact Disc Players

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle

    2006-01-01

    In order to improve Compact Disc Players playability regarding playing Compact Discs with surface faults, like scratches and fingerprints etc, the attention has been put on fault tolerant control schemes. Almost every of those methods are based on fault detection. The standard approach is to use...

  5. deposit, Singhbhum shear zone, eastern India

    Indian Academy of Sciences (India)

    Textural and compositional data of pyrites suggest that the hydrothermal fluid responsible for pre-/early-shearing mineralization evolved from Co-rich to Ni-rich and the late-/post-shearing fluid was largely depleted in minor elements. Sulphur isotope compositions of pyrite mostly furnish positive values ranging between ...

  6. Solvable groups and a shear construction

    DEFF Research Database (Denmark)

    Freibert, Marco; Swann, Andrew Francis

    The twist construction is a geometric model of T-duality that includes constructions of nilmanifolds from tori. This paper shows how one-dimensional foliations on manifolds may be used in a shear construction, which in algebraic form builds certain solvable Lie groups from Abelian ones. We discuss...... other examples of geometric structures that may be obtained from the shear construction....

  7. Rating precast prestressed concrete bridges for shear

    Science.gov (United States)

    2008-12-01

    Shear capacity of real-world prestressed concrete girders designed in the 1960s and 1970s is a concern because : AASHTO Standard Specifications (AASHTO-STD) employed the quarter-point rule for shear design, which is less : conservative for shea...

  8. Reversible Communicating Processes

    Directory of Open Access Journals (Sweden)

    Geoffrey Brown

    2016-02-01

    Full Text Available Reversible distributed programs have the ability to abort unproductive computation paths and backtrack, while unwinding communication that occurred in the aborted paths. While it is natural to assume that reversibility implies full state recovery (as with traditional roll-back recovery protocols, an interesting alternative is to separate backtracking from local state recovery. For example, such a model could be used to create complex transactions out of nested compensable transactions where a programmer-supplied compensation defines the work required to "unwind" a transaction. Reversible distributed computing has received considerable theoretical attention, but little reduction to practice; the few published implementations of languages supporting reversibility depend upon a high degree of central control. The objective of this paper is to demonstrate that a practical reversible distributed language can be efficiently implemented in a fully distributed manner. We discuss such a language, supporting CSP-style synchronous communication, embedded in Scala. While this language provided the motivation for the work described in this paper, our focus is upon the distributed implementation. In particular, we demonstrate that a "high-level" semantic model can be implemented using a simple point-to-point protocol.

  9. On compact galaxies in the UGC catalogue

    International Nuclear Information System (INIS)

    Kogoshvili, N.G.

    1980-01-01

    A problem of separation of compact galaxies in the UGC Catalogue is considered. Value of surface brightness equal to or less than 21sup(m) was used as compactness criterion from a square second of arc. 96 galaxies, which are brighter than 14sup(m)5 satisfy this criterion. Among compact galaxies discovered in the UGC Catalogue 7% are the Zwicky galaxies, 15% belong to the Markarian galaxies and 27% of galaxies are part of a galaxy list with high surface brightness. Considerable divergence in estimates of total share of compact galaxies in the B.A. Worontsov-Veljaminov Morphological Catalogue of Galaxies (MCG) and the UGC Catalogue is noted. This divergence results from systematical underestimation of visible sizes of compact galaxies in the MCG Catalogue as compared with the UGC Catalogue [ru

  10. Behaviour of Corroded Single Stud Shear Connectors

    Directory of Open Access Journals (Sweden)

    Wen Xue

    2017-03-01

    Full Text Available In this study, the effect of corrosion on the static behavior of stud shear connectors was investigated. An innovative test setup for single stud shear connectors was designed and established. Two series of specimens having different stud diameters were fabricated and tested. The test specimens were firstly corroded to different corrosion rates by the electronic accelerating method. Static loading tests were then performed to obtain the load-slip curves and ultimate strengths of the corroded test specimens. The actual corrosion rates were measured from the studs obtained from the tested specimens. The test results were compared with the push out test specimens having similar corrosion rates. It is shown that the test results obtained from the single stud shear connectors are conservative compared with the corroded push test specimens, which prove the validation of the single stud shear connector test method. The effect of corrosion on the behavior of stud shear connectors was also presented.

  11. Experimental study on the adiabatic shear bands

    International Nuclear Information System (INIS)

    Affouard, J.

    1984-07-01

    Four martensitic steels (Z50CDV5 steel, 28CND8 steel, 35NCDV16 steel and 4340 steel) with different hardness between 190 and 600 Hsub(B) (Brinell hardness), have been studied by means of dynamic compressive tests on split Hopkinson pressure bar. Microscopic observations show that the fracture are associated to the development of adiabatic shear bands (except 4340 steel with 190 Hsub(B) hardness). By means of tests for which the deformation is stopped at predetermined levels, the measurement of shear and hardness inside the band and the matrix indicates the chronology of this phenomenon: first the localization of shear, followed by the formation of adiabatic shear band and ultimatly crack initiation and propagation. These results correlated with few simulations by finite elements have permitted to suggest two mecanisms of deformation leading to the formation of adiabatic shear bands in this specific test [fr

  12. Friction of Shear-Fracture Zones

    Science.gov (United States)

    Riikilä, T. I.; Pylväinen, J. I.; Åström, J.

    2017-12-01

    A shear fracture of brittle solids under compression undergoes a substantial evolution from the initial microcracking to a fully formed powder-filled shear zone. Experiments covering the entire process are relatively easy to conduct, but they are very difficult to investigate in detail. Numerically, the large strain limit has remained a challenge. An efficient simulation model and a custom-made experimental device are employed to test to what extent a shear fracture alone is sufficient to drive material to spontaneous self-lubrication. A "weak shear zone" is an important concept in geology, and a large number of explanations, specific for tectonic conditions, have been proposed. We demonstrate here that weak shear zones are far more general, and that their emergence only demands that a microscopic, i.e., fragment-scale, stress relaxation mechanism develops during the fracture process.

  13. Imaging Shear Strength Along Subduction Faults

    Science.gov (United States)

    Bletery, Quentin; Thomas, Amanda M.; Rempel, Alan W.; Hardebeck, Jeanne L.

    2017-11-01

    Subduction faults accumulate stress during long periods of time and release this stress suddenly, during earthquakes, when it reaches a threshold. This threshold, the shear strength, controls the occurrence and magnitude of earthquakes. We consider a 3-D model to derive an analytical expression for how the shear strength depends on the fault geometry, the convergence obliquity, frictional properties, and the stress field orientation. We then use estimates of these different parameters in Japan to infer the distribution of shear strength along a subduction fault. We show that the 2011 Mw9.0 Tohoku earthquake ruptured a fault portion characterized by unusually small variations in static shear strength. This observation is consistent with the hypothesis that large earthquakes preferentially rupture regions with relatively homogeneous shear strength. With increasing constraints on the different parameters at play, our approach could, in the future, help identify favorable locations for large earthquakes.

  14. Simple shear of deformable square objects

    Science.gov (United States)

    Treagus, Susan H.; Lan, Labao

    2003-12-01

    Finite element models of square objects in a contrasting matrix in simple shear show that the objects deform to a variety of shapes. For a range of viscosity contrasts, we catalogue the changing shapes and orientations of objects in progressive simple shear. At moderate simple shear ( γ=1.5), the shapes are virtually indistinguishable from those in equivalent pure shear models with the same bulk strain ( RS=4), examined in a previous study. In theory, differences would be expected, especially for very stiff objects or at very large strain. In all our simple shear models, relatively competent square objects become asymmetric barrel shapes with concave shortened edges, similar to some types of boudin. Incompetent objects develop shapes surprisingly similar to mica fish described in mylonites.

  15. Imaging shear strength along subduction faults

    Science.gov (United States)

    Bletery, Quentin; Thomas, Amanda M.; Rempel, Alan W.; Hardebeck, Jeanne L.

    2017-01-01

    Subduction faults accumulate stress during long periods of time and release this stress suddenly, during earthquakes, when it reaches a threshold. This threshold, the shear strength, controls the occurrence and magnitude of earthquakes. We consider a 3-D model to derive an analytical expression for how the shear strength depends on the fault geometry, the convergence obliquity, frictional properties, and the stress field orientation. We then use estimates of these different parameters in Japan to infer the distribution of shear strength along a subduction fault. We show that the 2011 Mw9.0 Tohoku earthquake ruptured a fault portion characterized by unusually small variations in static shear strength. This observation is consistent with the hypothesis that large earthquakes preferentially rupture regions with relatively homogeneous shear strength. With increasing constraints on the different parameters at play, our approach could, in the future, help identify favorable locations for large earthquakes.

  16. Reversed extension flow

    DEFF Research Database (Denmark)

    Nielsen, Jens Kromann; Rasmussen, Henrik K.

    2008-01-01

    Afilament stretching rheometer (FSR) was used for measuring the start-up of uni-axial elongational flow followed by reversed bi-axial flow, both with a constant elongational rate. A narrow molecular mass distribution linear polystyrene with a molecular weight of 145 kg / mole wis subjected...... to the start-up of elongation for three Hencky strain units and subsequently the reversed flow. The integral molecular stress function formulation within the 'interchain pressure' concept agrees with the experiments. In the experiments the Hencky strain at which the str~ss becomes zero (the recovery strain......) in the reversed flow has been identified. The recovery strain is found to increase with elongational rate, and has a maximum value of approximately 1.45. The Doi Edwards model using any stretch evolution equation is not able to predict the correct level of the recovery strain....

  17. Jupiter's Great Red Spot: compactness condition and stability

    Directory of Open Access Journals (Sweden)

    Jun-Ichi Yano

    Full Text Available Linear Rossby wave dispersion relationships suggest that Jupiter's Great Red Spot (GRS is a baroclinic structure embedded in a barotropic shearing zonal flow. Quasi-geostrophic (QG two-layer simulations support the theory, as long as an infinitely deep zonal flow is assumed. However, once a finite depth of the lower layer is assumed, a self-interaction of the baroclinic eddy component produces a barotropic radiating field, so that the GRS-like eddy can no longer remain compact. Compactness is recovered by explicitly introducing a deep dynamics of the interior for the lower layer, instead of the shallow QG formulation. An implication of the result is a strong coupling of the GRS to a convectively active interior.

  18. Hydrodynamic of a deformed bubble in linear shear flow; Hydrodynamique d'une bulle deformee dans un ecoulement cisaille

    Energy Technology Data Exchange (ETDEWEB)

    Adoua, S.R

    2007-07-15

    This work is devoted to the study of an oblate spheroidal bubble of prescribed shape set fixed in a linear shear flow using direct numerical simulation. The three dimensional Navier-Stokes equations are solved in orthogonal curvilinear coordinates using a finite volume method. The bubble response is studied over a wide range of the aspect ratio (1-2.7), the bubble Reynolds number (50-2000) and the non-dimensional shear rate (0.-1.2). The numerical simulations shows that the shear flow imposes a plane symmetry of the wake whatever the parameters of the flow. The trailing vorticity is organized into two anti-symmetrical counter rotating tubes with a sign imposed by the competition of two mechanisms (the Lighthill mechanism and the instability of the wake). Whatever the Reynolds number, the lift coefficient reaches the analytical value obtained in an inviscid, weakly sheared flow corresponding to a lift force oriented in the same direction as that of a spherical bubble. For moderate Reynolds numbers, the direction of the lift force reverses when the bubble aspect ratio is large enough as observed in experiments. This reversal occurs for aspect ratios larger than 2.225 and is found to be directly linked to the sign of the trailing vorticity which is concentrated within two counter-rotating threads which propel the bubble in a direction depending of their sign of rotation. The behavior of the drag does not revel any significant effect induced by the wake structure and follows a quadratic increase with the shear rate. Finally, the torque experienced by the bubble also reverses for the same conditions inducing the reversal of the lift force. By varying the orientation of the bubble in the shear flow, a stable equilibrium position is found corresponding to a weak angle between the small axis of the bubble and the flow direction. (author)

  19. High-shear granulation as a manufacturing method for cocrystal granules

    DEFF Research Database (Denmark)

    Rehder, Sönke; Christensen, Niels Peter Aae; Rantanen, Jukka

    2013-01-01

    influenced by the excipients, since in presence of calcium hydrogenphosphate, the poorly water-soluble salt calcium tartrate monohydrate was formed at high relative humidity. Interestingly, compactability was increased by cocrystal formation compared to that of the reference granules (piracetam......Cocrystal formation allows the tailoring of physicochemical as well as of mechanical properties of an API. However, there is a lack of large-scale manufacturing methods of cocrystals. Therefore, the objective of this work was to examine the suitability of high-shear wet granulation...... as a manufacturing method for cocrystal granules on a batch scale. Furthermore, the cocrystal granules were characterized regarding their mechanical properties as well as their dissolution behavior. High-shear wet granulation was found to be a feasible manufacturing method for cocrystal granules. Cocrystal formation...

  20. Assessment of the mechanical properties of sisal fiber-reinforced silty clay using triaxial shear tests.

    Science.gov (United States)

    Wu, Yankai; Li, Yanbin; Niu, Bin

    2014-01-01

    Fiber reinforcement is widely used in construction engineering to improve the mechanical properties of soil because it increases the soil's strength and improves the soil's mechanical properties. However, the mechanical properties of fiber-reinforced soils remain controversial. The present study investigated the mechanical properties of silty clay reinforced with discrete, randomly distributed sisal fibers using triaxial shear tests. The sisal fibers were cut to different lengths, randomly mixed with silty clay in varying percentages, and compacted to the maximum dry density at the optimum moisture content. The results indicate that with a fiber length of 10 mm and content of 1.0%, sisal fiber-reinforced silty clay is 20% stronger than nonreinforced silty clay. The fiber-reinforced silty clay exhibited crack fracture and surface shear fracture failure modes, implying that sisal fiber is a good earth reinforcement material with potential applications in civil engineering, dam foundation, roadbed engineering, and ground treatment.

  1. Flow simulation of fiber reinforced self compacting concrete using Lattice Boltzmann method

    DEFF Research Database (Denmark)

    Svec, Oldrich; Skocek, Jan; Stang, Henrik

    2011-01-01

    to the compression strength and, therefore, it needs to be reinforced. Fiber reinforced concrete is an alternative to traditional stirrups reinforcement leading to lowered labor costs. To be able to access mechanical properties of the fiber reinforced concrete, knowledge of final spread and directions of fibers......Self compacting concrete (SCC) is a promising material in the civil engineering industry. One of the benefits of the SCC is a fast and simplified casting followed by decreased labor costs. The SCC as any other type of concrete has a significantly lower tensile and shear strength in comparison...

  2. Theory of field-reversed configurations

    International Nuclear Information System (INIS)

    Steinhauer, L.C.

    1993-01-01

    This report summarizes results from the theoretical program on field reversed configurations (FRC) at STI Optronics. The program, which has spanned the last 13 years, has included analytical as well as computational components. It has led to published papers on every major topic of FRC theory. The report is outlined to summarize results from each of these topic areas: formation, equilibrium, stability, and confinement. Also briefly described are Steinhauer's activities as Compact Toroid Theory Listening Post. Appendix A is a brief listing of the major advances achieved in this program. Attached at the back of this report is a collection of technical papers in archival journals that resulted from work in this program. The discussion within each subsection is given chronologically in order to give a historical sense of the evolution of understanding of FRC physics

  3. Rotational instabilities in field reversed configurations

    International Nuclear Information System (INIS)

    Santiago, M.A.M.; Tsui, K.H.; Ponciano, B.M.B.; Sakanaka, P.H.

    1988-01-01

    The rotational instability (n = 2 toroidal mode) in field reversed configurations (FRC) using the ideal MHD equations in cylindrical geometry is studied. These equations are solved using a realistic densite profile, and the influence of some plasma parameters on the growth rate is analysed. The model shows good qualitative results. The growth rate increases rapidly as rotational frequency goes up and the mode m = 2 dominates over the m = 1 mode. With the variation of the density profile, it is observed that the growth rate decreases as the density dip at the center fills up. Calculated value ranges from 1/2 to 1/7 of the rotational frequency Ω whereas the measured value is around Ω/50. The developed analysis is valid for larger machines. The influence of the plasma resistivity on the mode stabilization is also analysed. The resistivity, which is the fundamental factor in the formation of compact torus, tends to decrease the growth rate. (author) [pt

  4. Experimental and numerical contribution to heat transfer enhancement in compact plate heat exchangers

    International Nuclear Information System (INIS)

    Vitillo, Francesco

    2014-01-01

    In the framework of CEA R and D program to develop an industrial prototype of Sodium cooled Fast Reactor, the present thesis aimed to propose an innovative compact heat exchanger technology. In order to increase the global compactness the basic idea of this work is to design a channel were the fluid flow is as much three-dimensional as possible. In particular the channel can be thought as the result of the superposition of two undulated channels in phase opposition. To numerically provide a physically-consistent model, a new non-linear eddy viscosity named Anisotropic Shear Stress Transport (ASST) model has been developed and implemented into the available solver ANSYS FLUENT. To validate the numerical model, two experimental sections have been used to acquire an extensive aerodynamic database, whereas, to validate the thermal modeling approach, the VHEGAS facility has been built. Once having validated the ASST model, correlations for friction factor and Nusselt number for various geometries could be obtained. Finally, it has been shown that the innovative channel is the most compact one among the most important existing industrial compact heat exchanger technologies. (author) [fr

  5. Development of a MEMS dual-axis differential capacitance floating element shear stress sensor

    Energy Technology Data Exchange (ETDEWEB)

    Barnard, Casey [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Griffin, Benjamin [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    A single-axis MEMS wall shear stress sensor with differential capacitive transduction method is produced. Using a synchronous modulation and demodulation interface circuit, the system is capable of making real time measurements of both mean and fluctuating wall shear stress. A sensitivity of 3.44 mV/Pa is achieved, with linearity in response demonstrated up to testing limit of 2 Pa. Minimum detectable signals of 340 μPa at 100 Hz and 120 μPa at 1 kHz are indicated, with a resonance of 3.5 kHz. Multiple full scale wind tunnel tests are performed, producing spectral measurements of turbulent boundary layers in wind speeds ranging up to 0.5 Ma (18 Pa of mean wall shear stress). The compact packaging allows for minimally invasive installation, and has proven relatively robust over multiple testing events. Temperature sensitivity, likely due to poor CTE matching of packaged materials, is an ongoing concern being addressed. These successes are being directly leveraged into a development plan for a dual-axis wall shear stress sensor, capable of producing true vector estimates at the wall.

  6. Compaction Bands Around Unstable Wellbores In Porous Sandstone and Their Dependence On Grain Bonding

    Science.gov (United States)

    Haimson, B.; Klaetsch, A.

    Compaction bands are narrow tabular zones of localized deformation that accommodate pure compaction and no shear and form perpendicular to the maximum principal stress. They have been observed in moderate- to high- porosity sandstones, and are of substantial practical importance in that their reduced porosity compared with that of the surrounding rock creates a potential barrier to flow in aquifers or oil reservoirs. We have conducted laboratory simulations of fie ld deep drilling by boring 20 mm-diameter holes into 150×150×230 mm rock blocks subjected to true triaxial far-field stresses (H>v>h), and found that beyond a threshold of horizontal stress differential borehole instability takes the form of `breakouts'. In granite, limestone, and 17%-porosity Berea sandstone breakouts have the typical shallow dog-eared shape. Thin section study shows that grain bonding in the 17% Berea sandstone is by iron-rich clay mineral cementation. However, breakouts in 25%-porosity Berea as well as in St. Peter sandstone are fracture-like, very long and narrow (several grain diameters), and oriented counterintuitively perpendicular to h direction. A narrow zone of compacted grains just ahead of the breakout tip is observed, resembling a compaction band. Breakouts in these rocks appear to be merely emptied compaction bands with debonded grains flushed off primarily by the circulating drilling fluid. Thin sections reveal that grain bonding, leading to formation of compaction bands and subsequently of fracture-like breakouts, is primarily by sutured contacts. In the 25% Berea as well as in the 18% St. Peter sandstone almost all compacted and debonded grains are intact, suggesting that failure occurs at grain sutures, while in the 12% St. Peter a narrow zone of crushed grains is clearly evident, caused by extensive failure of both sutured grain contacts and the grains themselves. The explanation for this micromechanical behavior lies in the additional observation that in the higher

  7. A compact tritium AMS system

    International Nuclear Information System (INIS)

    Roberts, M.L.; Hamm, R.W.; Dingley, K.H.; Chiarappa-Zucca, M.L.; Love, A.H.

    2000-01-01

    Tritium ( 3 H) is a radioisotope that is extensively utilized in biological and environmental research. For biological research, 3 H is generally quantified by liquid scintillation counting requiring gram-sized samples and counting times of several hours. For environmental research, 3 H is usually quantified by 3 He in-growth which requires gram-sized samples and in-growth times of several months. In contrast, provisional studies at LLNL's Center for Accelerator Mass Spectrometry have demonstrated that accelerator mass spectrometry (AMS) can be used to quantify 3 H in milligram-sized biological samples with a 100 to 1000-fold improvement in detection limits when compared to scintillation counting. This increased sensitivity is expected to have great impact on the biological and environmental research community. However, in order to make the 3 H AMS technique more broadly accessible, smaller, simpler, and less expensive AMS instrumentation must be developed. To meet this need, a compact, relatively low cost prototype 3 H AMS system has been designed and built based on an LLNL ion source/sample changer and an AccSys Technology radio frequency quadrupole (RFQ) linac. With the prototype system, 3 H/ 1 H ratios ranging from 1x10 -10 to 1x10 -13 have be measured from milligram-sized samples. With improvements in system operation and sample preparation methodology, the sensitivity limit of the system is expected to increase to approximately 1x10 -15

  8. Compact, Pneumatically Actuated Filter Shuttle

    Science.gov (United States)

    Leighy, Bradley D.

    2003-01-01

    A compact, pneumatically actuated filter shuttle has been invented to enable alternating imaging of a wind-tunnel model in two different spectral bands characteristic of the pressure and temperature responses of a pressure and temperature-sensitive paint. This filter shuttle could also be used in other settings in which there are requirements for alternating imaging in two spectral bands. Pneumatic actuation was chosen because of a need to exert control remotely (that is, from outside the wind tunnel) and because the power leads that would be needed for electrical actuation would pose an unacceptable hazard in the wind tunnel. The entire shuttle mechanism and its housing can be built relatively inexpensively [camera used for viewing the wind-tunnel model. The mechanism includes a pneumatic actuator connected to a linkage. The linkage converts the actuator stroke to a scissor-like motion that places one filter in front of the camera and the other filter out of the way. Optoelectronic sensors detect tabs on the sliding panels for verification of the proper positioning of the filters.

  9. Compact dynamic microfluidic iris array

    Science.gov (United States)

    Kimmle, Christina; Doering, Christoph; Steuer, Anna; Fouckhardt, Henning

    2011-09-01

    A dynamic microfluidic iris is realized. Light attenuation is achieved by absorption of an opaque liquid (e.g. black ink). The adjustment of the iris diameter is achieved by fluid displacement via a transparent elastomer (silicone) half-sphere. This silicone calotte is hydraulically pressed against a polymethylmethacrylate (PMMA) substrate as the bottom window, such that the opaque liquid is squeezed away, this way opening the iris. With this approach a dynamic range of more than 60 dB can be achieved with response times in the ms to s regime. The design allows the realization of a single iris as well as an iris array. So far the master for the molded silicone structure was fabricated by precision mechanics. The aperture diameter was changed continuously from 0 to 8 mm for a single iris and 0 to 4 mm in case of a 3 x 3 iris array. Moreover, an iris array was combined with a PMMA lens array into a compact module, the distance of both arrays equaling the focal length of the lenses. This way e.g. spatial frequency filter arrays can be realized. The possibility to extend the iris array concept to an array with many elements is demonstrated. Such arrays could be applied e.g. in light-field cameras.

  10. Cooling of hypernuclear compact stars

    Science.gov (United States)

    Raduta, Adriana R.; Sedrakian, Armen; Weber, Fridolin

    2018-04-01

    We study the thermal evolution of hypernuclear compact stars constructed from covariant density functional theory of hypernuclear matter and parametrizations which produce sequences of stars containing two-solar-mass objects. For the input in the simulations, we solve the Bardeen-Cooper-Schrieffer gap equations in the hyperonic sector and obtain the gaps in the spectra of Λ, Ξ0, and Ξ- hyperons. For the models with masses M/M⊙ ≥ 1.5 the neutrino cooling is dominated by hyperonic direct Urca processes in general. In the low-mass stars the (Λp) plus leptons channel is the dominant direct Urca process, whereas for more massive stars the purely hyperonic channels (Σ-Λ) and (Ξ-Λ) are dominant. Hyperonic pairing strongly suppresses the processes on Ξ-s and to a lesser degree on Λs. We find that intermediate-mass 1.5 ≤ M/M⊙ ≤ 1.8 models have surface temperatures which lie within the range inferred from thermally emitting neutron stars, if the hyperonic pairing is taken into account. Most massive models with M/M⊙ ≃ 2 may cool very fast via the direct Urca process through the (Λp) channel because they develop inner cores where the S-wave pairing of Λs and proton is absent.

  11. Laboratory evaluation of friction loss and compactability of asphalt mixtures.

    Science.gov (United States)

    2012-04-01

    This study aimed to develop prediction models for friction loss and laboratory compaction of asphalt : mixtures. In addition, the study evaluated the effect of compaction level and compaction method of skid : resistance and the internal structure of ...

  12. A case study of intelligent compaction used in road upgrades

    CSIR Research Space (South Africa)

    Leyland, R

    2014-08-01

    Full Text Available is that of intelligent compaction (IC) systems. As a whole such systems are said to provide numerous advantages including increased productivity, proactive compaction process adjustment, reduced spatial variations in compaction and greater data coverage compared...

  13. Implementation of intelligent compaction technologies for road constructions in Wyoming.

    Science.gov (United States)

    2015-03-01

    Conventional test methods for roadway compaction cover less than 1% of roadway; whereas, intelligent : compaction (IC) offers a method to measure 100% of a roadway. IC offers the ability to increase : compaction uniformity of soils and asphalt paveme...

  14. Effects of Fluid Shear Stress on Expression of Smac/DIABLO in Human Umbilical Vein Endothelial Cells.

    Science.gov (United States)

    Zhang, Feng; Zhang, Le; Sun, Liang-Liang; Meng, Xiang-Lan; Zhao, Yun; Jin, Xin

    2013-06-01

    To investigate the molecular mechanisms of laminar shear stress on inhibition of apoptosis in endothelial cells, human umbilical vein endothelial cells (HUVECs) were starved in medium containing 2% fetal bovine serum and 20 dyne/cm(2) shear stress. HUVECs were subjected to shear stress or incubated in a static condition and then Smac/DIABLO expression was quantified by reverse-transcription polymerase chain reaction, real-time PCR, and western blot. The effect of shear stress on the migration of Smac/DIABLO proteins was detected by immunofluorescence microscopy. Results demonstrated that 20 dyne/cm(2) shear stress inhibited the expression of Smac/DIABLO at both the mRNA and protein levels in cultured HUVECs. Furthermore, release of Smac/DIABLO from mitochondria was induced by removal of basic fibroblast growth factor and decrease of fetal bovine serum in the medium, whereas shear stress inhibited its release under the same conditions. These results suggest that down-regulation of Smac/DIABLO may contribute to the potent antiatherosclerotic effect of shear stress by preventing endothelial cells from entering apoptosis.

  15. Thermal electron transport in regimes with low and negative magnetic shear in Tore Supra

    International Nuclear Information System (INIS)

    Voitsekhovitch, I.; Litaudon, X.; Moreau, D.; Aniel, T.; Becoulet, A.; Erba, M.; Joffrin, E.; Kazarian-Vibert, F.; Peysson, Y.

    1997-01-01

    The magnetic shear effect on thermal electron transport is studied in a large variety of non-inductive plasmas in Tore Supra. An improved confinement in the region of low and negative shear was observed and quantified with an exponential dependence on the magnetic shear (Litaudon, et al., Fusion Energy 1996 (Proc. 16th Int. Conf. Montreal, 1996), Vol. 1, IAEA, Vienna (1997) 669). This is interpreted as a consequence of a decoupling of the global modes (Romanelli and Zonca, Phys. Fluids B 5 (1993) 4081) that are thought to be responsible for anomalous transport. This dependence is proposed in order to complete the Bohm-like L mode local electron thermal diffusivity so as to describe the transition from Bohm-like to gyroBohm transport in the plasma core. The good agreement between the predictive simulations of the different Tore Supra regimes (hot core lower hybrid enhanced performance, reversed shear plasmas and combined lower hybrid current drive and fast wave electron heating) and experimental data provides a basis for extrapolation of this magnetic shear dependence in the local transport coefficients to future machines. As an example, a scenario for non-inductive current profile optimization and control in ITER is presented. (author)

  16. Thermal conductivity of graphene nanoribbons under shear deformation: A molecular dynamics simulation

    Science.gov (United States)

    Zhang, Chao; Hao, Xiao-Li; Wang, Cui-Xia; Wei, Ning; Rabczuk, Timon

    2017-01-01

    Tensile strain and compress strain can greatly affect the thermal conductivity of graphene nanoribbons (GNRs). However, the effect of GNRs under shear strain, which is also one of the main strain effect, has not been studied systematically yet. In this work, we employ reverse nonequilibrium molecular dynamics (RNEMD) to the systematical study of the thermal conductivity of GNRs (with model size of 4 nm × 15 nm) under the shear strain. Our studies show that the thermal conductivity of GNRs is not sensitive to the shear strain, and the thermal conductivity decreases only 12–16% before the pristine structure is broken. Furthermore, the phonon frequency and the change of the micro-structure of GNRs, such as band angel and bond length, are analyzed to explore the tendency of thermal conductivity. The results show that the main influence of shear strain is on the in-plane phonon density of states (PDOS), whose G band (higher frequency peaks) moved to the low frequency, thus the thermal conductivity is decreased. The unique thermal properties of GNRs under shear strains suggest their great potentials for graphene nanodevices and great potentials in the thermal managements and thermoelectric applications. PMID:28120921

  17. Thermal electron transport in the regimes with low and negative magnetic shear on tore supra

    International Nuclear Information System (INIS)

    Voitsekhovitch, I.; Litaudon, X.; Moreau, D.; Aniel, T.; Becoulet, A.; Erba, M.; Joffrin, E.; Kazarian-Vibert, F.; Peysson, Y.

    1997-04-01

    The magnetic shear effect on the thermal electron transport is studied in a large variety of non-inductive plasmas of Tore Supra. An improved confinement in the region of low and negative shear was observed and quantified with an exponential dependence on the magnetic shear [Litaudon et al. in Plasma Physics and Controlled Nuclear Fusion Research, 1996, Montreal (International Atomic Energy Agency, Vienna, 1997) to be published]. This is interpreted as the consequence of a decoupling of the global modes [Romanelli and Zonka, Phys. Fluids B5 (1993), 4081] which are thought to be responsible for anomalous transport. This dependence is proposed to complete the Bohm-like L-mode local electron thermal diffusivity to describe the transition from the Bohm-like to the gyro-Bohm transport in the plasma core. The good agreement between the predictive simulations of the different Tore Supra regimes (hot core lower hybrid enhanced performance, reversed shear plasmas and combined lower hybrid current drive and fast wave electron heating) and experimental data gives a basis for the extrapolation of this magnetic shear dependence in the local transport coefficients for future machines. As an example a scenario for non-inductive current profile optimisation and control in ITER is presented. (author)

  18. Thermal conductivity of graphene nanoribbons under shear deformation: A molecular dynamics simulation.

    Science.gov (United States)

    Zhang, Chao; Hao, Xiao-Li; Wang, Cui-Xia; Wei, Ning; Rabczuk, Timon

    2017-01-25

    Tensile strain and compress strain can greatly affect the thermal conductivity of graphene nanoribbons (GNRs). However, the effect of GNRs under shear strain, which is also one of the main strain effect, has not been studied systematically yet. In this work, we employ reverse nonequilibrium molecular dynamics (RNEMD) to the systematical study of the thermal conductivity of GNRs (with model size of 4 nm × 15 nm) under the shear strain. Our studies show that the thermal conductivity of GNRs is not sensitive to the shear strain, and the thermal conductivity decreases only 12-16% before the pristine structure is broken. Furthermore, the phonon frequency and the change of the micro-structure of GNRs, such as band angel and bond length, are analyzed to explore the tendency of thermal conductivity. The results show that the main influence of shear strain is on the in-plane phonon density of states (PDOS), whose G band (higher frequency peaks) moved to the low frequency, thus the thermal conductivity is decreased. The unique thermal properties of GNRs under shear strains suggest their great potentials for graphene nanodevices and great potentials in the thermal managements and thermoelectric applications.

  19. Nuclear Activity of Compact Group Galaxies

    Science.gov (United States)

    Jubee, Sohn; Hwang, H.; Lee, M.; Lee, G.; Lee, J.

    2013-01-01

    We present results of a study on nuclear activities of compact group galaxies in the local universe. The triggering mechanism of AGN is an intriguing proble, and one of the suggested AGN triggering mechanism is galaxy interaction. In this regard, compact groups are a great laboratory to study the connection between galaxy interaction and nuclear activities. To study the environmental effects on nuclear activity, we estimate the fraction of AGN-host galaxies for a spectroscopic sample of 238 member galaxies in 59 compact groups from the Sloan Digital Sky Survey using the emission-line ratio diagnostic diagrams in comparison with field and cluster regions. We derive the 17-42% of AGN fraction of the compact groups depending on the AGN classification methods. The AGN fraction of compact groups is not the highest among the galaxy environments for both early and late type galaxies. We also examine the environmental dependence of nuclear activity using the surface galaxy number density. For early type galaxies, the AGN fraction decreases with increasing galaxy number density, while the AGN fraction of late-type galaxies barely changes. Moreover, we do not find any mid-infrared detected AGN-host compact group galaxies in our sample using WISE photometry. These results imply that the compact group galaxies is not stronngly active because of lack of gas supply, in contrast to the expectation that they may experience frequent galaxy-galaxy interactions.

  20. Does soil compaction increase floods? A review

    Science.gov (United States)

    Alaoui, Abdallah; Rogger, Magdalena; Peth, Stephan; Blöschl, Günter

    2018-02-01

    Europe has experienced a series of major floods in the past years which suggests that flood magnitudes may have increased. Land degradation due to soil compaction from crop farming or grazing intensification is one of the potential drivers of this increase. A literature review suggests that most of the experimental evidence was generated at plot and hillslope scales. At larger scales, most studies are based on models. There are three ways in which soil compaction affects floods at the catchment scale: (i) through an increase in the area affected by soil compaction; (ii) by exacerbating the effects of changes in rainfall, especially for highly degraded soils; and (iii) when soil compaction coincides with soils characterized by a fine texture and a low infiltration capacity. We suggest that future research should focus on better synthesising past research on soil compaction and runoff, tailored field experiments to obtain a mechanistic understanding of the coupled mechanical and hydraulic processes, new mapping methods of soil compaction that combine mechanical and remote sensing approaches, and an effort to bridge all disciplines relevant to soil compaction effects on floods.

  1. Shear-induced APAP de-agglomeration.

    Science.gov (United States)

    Llusa, Marcos; Levin, Michael; Snee, Ronald D; Muzzio, Fernando J

    2009-12-01

    Active pharmaceutical ingredient agglomerates can generate many solid product regulatory compliance issues. To study the effects of shear rate, strain, type of excipient, and grade of acetaminophen (APAP) on the process of APAP de-agglomeration. A shear-controlled environment is used to expose six different blends that consist of one of three APAP grades and one of two possible types of excipient to 10 different combinations of shear rate and strain. APAP agglomerates are sifted and weighed. Finer APAP grades lead to blends with more APAP agglomerates and type of excipient only affects the de-agglomeration process for the finest APAP grade. De-agglomeration proceeds mainly as a function of strain with a minor contribution toward further de-agglomeration when larger shear rates are used. When mechanical stress (which us proportional to shear rate) overcomes interparticle forces, de-agglomeration occurs. Higher shear rates (and stress) contribute slightly to further APAP de-agglomeration. Extended exposure to stress (strain) reduces the size and the number of agglomerates. Blends with finer APAP present more agglomerates, particularly after low strain exposure. This article presents a useful method for formulation and process development. Exposing blends to higher shear rates and especially to strain mitigates APAP agglomeration in blends. Finer APAP presents more agglomerates and the type of excipient used affects the degree of APAP agglomeration.

  2. Surface shear inviscidity of soluble surfactants.

    Science.gov (United States)

    Zell, Zachary A; Nowbahar, Arash; Mansard, Vincent; Leal, L Gary; Deshmukh, Suraj S; Mecca, Jodi M; Tucker, Christopher J; Squires, Todd M

    2014-03-11

    Foam and emulsion stability has long been believed to correlate with the surface shear viscosity of the surfactant used to stabilize them. Many subtleties arise in interpreting surface shear viscosity measurements, however, and correlations do not necessarily indicate causation. Using a sensitive technique designed to excite purely surface shear deformations, we make the most sensitive and precise measurements to date of the surface shear viscosity of a variety of soluble surfactants, focusing on SDS in particular. Our measurements reveal the surface shear viscosity of SDS to be below the sensitivity limit of our technique, giving an upper bound of order 0.01 μN·s/m. This conflicts directly with almost all previous studies, which reported values up to 10(3)-10(4) times higher. Multiple control and complementary measurements confirm this result, including direct visualization of monolayer deformation, for SDS and a wide variety of soluble polymeric, ionic, and nonionic surfactants of high- and low-foaming character. No soluble, small-molecule surfactant was found to have a measurable surface shear viscosity, which seriously undermines most support for any correlation between foam stability and surface shear rheology of soluble surfactants.

  3. IMAGE ANALYSIS FOR MODELLING SHEAR BEHAVIOUR

    Directory of Open Access Journals (Sweden)

    Philippe Lopez

    2011-05-01

    Full Text Available Through laboratory research performed over the past ten years, many of the critical links between fracture characteristics and hydromechanical and mechanical behaviour have been made for individual fractures. One of the remaining challenges at the laboratory scale is to directly link fracture morphology of shear behaviour with changes in stress and shear direction. A series of laboratory experiments were performed on cement mortar replicas of a granite sample with a natural fracture perpendicular to the axis of the core. Results show that there is a strong relationship between the fracture's geometry and its mechanical behaviour under shear stress and the resulting damage. Image analysis, geostatistical, stereological and directional data techniques are applied in combination to experimental data. The results highlight the role of geometric characteristics of the fracture surfaces (surface roughness, size, shape, locations and orientations of asperities to be damaged in shear behaviour. A notable improvement in shear understanding is that shear behaviour is controlled by the apparent dip in the shear direction of elementary facets forming the fracture.

  4. Shear rheology of molten crumb chocolate.

    Science.gov (United States)

    Taylor, J E; Van Damme, I; Johns, M L; Routh, A F; Wilson, D I

    2009-03-01

    The shear rheology of fresh molten chocolate produced from crumb was studied over 5 decades of shear rate using controlled stress devices. The Carreau model was found to be a more accurate description than the traditional Casson model, especially at shear rates between 0.1 and 1 s(-1). At shear rates around 0.1 s(-1) (shear stress approximately 7 Pa) the material exhibited a transition to a solid regime, similar to the behavior reported by Coussot (2005) for other granular suspensions. The nature of the suspension was explored by investigating the effect of solids concentration (0.20 chocolate was then compared with the rheology of (1) a synthetic chocolate, which contained sunflower oil in place of cocoa butter, and (2) a suspension of sugar of a similar size distribution (volume mean 15 mum) in cocoa butter and emulsifier. The chocolate and synthetic chocolate showed very similar rheological profiles under both steady shear and oscillatory shear. The chocolate and the sugar suspension showed similar Krieger-Dougherty dependency on volume fraction, and a noticeable transition to a stiff state at solids volume fractions above approximately 0.5. Similar behavior has been reported by Citerne and others (2001) for a smooth peanut butter, which had a similar particle size distribution and solids loading to chocolate. The results indicate that the melt rheology of the chocolate is dominated by hydrodynamic interactions, although at high solids volume fractions the emulsifier may contribute to the departure of the apparent viscosity from the predicted trend.

  5. [Exercise-induced shear stress: Physiological basis and clinical impact].

    Science.gov (United States)

    Rodríguez-Núñez, Iván; Romero, Fernando; Saavedra, María Javiera

    2016-01-01

    The physiological regulation of vascular function is essential for cardiovascular health and depends on adequate control of molecular mechanisms triggered by endothelial cells in response to mechanical and chemical stimuli induced by blood flow. Endothelial dysfunction is one of the major risk factors for cardiovascular disease, where an imbalance between synthesis of vasodilator and vasoconstrictor molecules is one of its main mechanisms. In this context, the shear stress is one of the most important mechanical stimuli to improve vascular function, due to endothelial mechanotransduction, triggered by stimulation of various endothelial mechanosensors, induce signaling pathways culminating in increased bioavailability of vasodilators molecules such as nitric oxide, that finally trigger the angiogenic mechanisms. These mechanisms allow providing the physiological basis for the effects of exercise on vascular health. In this review it is discussed the molecular mechanisms involved in the vascular response induced by shear stress and its impact in reversing vascular injury associated with the most prevalent cardiovascular disease in our population. Copyright © 2016 Instituto Nacional de Cardiología Ignacio Chávez. Publicado por Masson Doyma México S.A. All rights reserved.

  6. Time reversal communication system

    Science.gov (United States)

    Candy, James V.; Meyer, Alan W.

    2008-12-02

    A system of transmitting a signal through a channel medium comprises digitizing the signal, time-reversing the digitized signal, and transmitting the signal through the channel medium. The channel medium may be air, earth, water, tissue, metal, and/or non-metal.

  7. Engineering Encounters: Reverse Engineering

    Science.gov (United States)

    McGowan, Veronica Cassone; Ventura, Marcia; Bell, Philip

    2017-01-01

    This column presents ideas and techniques to enhance your science teaching. This month's issue shares information on how students' everyday experiences can support science learning through engineering design. In this article, the authors outline a reverse-engineering model of instruction and describe one example of how it looked in our fifth-grade…

  8. Sex Reversal in Birds.

    Science.gov (United States)

    Major, Andrew T; Smith, Craig A

    2016-01-01

    Sexual differentiation in birds is controlled genetically as in mammals, although the sex chromosomes are different. Males have a ZZ sex chromosome constitution, while females are ZW. Gene(s) on the sex chromosomes must initiate gonadal sex differentiation during embryonic life, inducing paired testes in ZZ individuals and unilateral ovaries in ZW individuals. The traditional view of avian sexual differentiation aligns with that expounded for other vertebrates; upon sexual differentiation, the gonads secrete sex steroid hormones that masculinise or feminise the rest of the body. However, recent studies on naturally occurring or experimentally induced avian sex reversal suggest a significant role for direct genetic factors, in addition to sex hormones, in regulating sexual differentiation of the soma in birds. This review will provide an overview of sex determination in birds and both naturally and experimentally induced sex reversal, with emphasis on the key role of oestrogen. We then consider how recent studies on sex reversal and gynandromorphic birds (half male:half female) are shaping our understanding of sexual differentiation in avians and in vertebrates more broadly. Current evidence shows that sexual differentiation in birds is a mix of direct genetic and hormonal mechanisms. Perturbation of either of these components may lead to sex reversal. © 2016 S. Karger AG, Basel.

  9. Strategy Guideline. Compact Air Distribution Systems

    Energy Technology Data Exchange (ETDEWEB)

    Burdick, Arlan [IBACOS, Inc., Pittsburgh, PA (United States)

    2013-06-01

    This guideline discusses the benefits and challenges of using a compact air distribution system to handle the reduced loads and reduced air volume needed to condition the space within an energy efficient home. The decision criteria for a compact air distribution system must be determined early in the whole-house design process, considering both supply and return air design. However, careful installation of a compact air distribution system can result in lower material costs from smaller equipment, shorter duct runs, and fewer outlets; increased installation efficiencies, including ease of fitting the system into conditioned space; lower loads on a better balanced HVAC system, and overall improved energy efficiency of the home.

  10. Generalised model for anisotropic compact stars

    Energy Technology Data Exchange (ETDEWEB)

    Maurya, S.K. [University of Nizwa, Department of Mathematical and Physical Sciences College of Arts and Science, Nizwa (Oman); Gupta, Y.K. [Raj Kumar Goel Institute of Technology, Department of Mathematics, Ghaziabad, Uttar Pradesh (India); Ray, Saibal [Government College of Engineering and Ceramic Technology, Department of Physics, Kolkata, West Bengal (India); Deb, Debabrata [Indian Institute of Engineering Science and Technology, Shibpur, Department of Physics, Howrah, West Bengal (India)

    2016-12-15

    In the present investigation an exact generalised model for anisotropic compact stars of embedding class 1 is sought with a general relativistic background. The generic solutions are verified by exploring different physical aspects, viz. energy conditions, mass-radius relation, stability of the models, in connection to their validity. It is observed that the model presented here for compact stars is compatible with all these physical tests and thus physically acceptable as far as the compact star candidates RXJ 1856-37, SAX J 1808.4-3658 (SS1) and SAX J 1808.4-3658 (SS2) are concerned. (orig.)

  11. Compact vs. Exponential-Size LP Relaxations

    Energy Technology Data Exchange (ETDEWEB)

    Carr, R.D.; Lancia, G.

    2000-09-01

    In this paper we introduce by means of examples a new technique for formulating compact (i.e. polynomial-size) LP relaxations in place of exponential-size models requiring separation algorithms. In the same vein as a celebrated theorem by Groetschel, Lovasz and Schrijver, we state the equivalence of compact separation and compact optimization. Among the examples used to illustrate our technique, we introduce a new formulation for the Traveling Salesman Problem, whose relaxation we show equivalent to the subtour elimination relaxation.

  12. Shear reinforced beams in autoclaved aerated concrete

    DEFF Research Database (Denmark)

    Cornelius, Thomas

    2010-01-01

    combinations of reinforcement and for variable slenderness ratios. Theoretical approaches will be evaluated and compared with the test results of several test series. The load bearing capacity of shear reinforced aircrete is highly dependent on the anchorage and bond behaviour of the shear reinforcement......Shear behaviour in concrete materials is very well documented, for normal density concrete materials. In this paper results of various tests on low density concrete materials like aerated autoclaved concrete (in the following denoted aircrete) will be presented and analyzed for different...

  13. Shear viscosity of liquid mixtures Mass dependence

    CERN Document Server

    Kaushal, R

    2002-01-01

    Expressions for zeroth, second, and fourth sum rules of transverse stress autocorrelation function of two component fluid have been derived. These sum rules and Mori's memory function formalism have been used to study shear viscosity of Ar-Kr and isotopic mixtures. It has been found that theoretical result is in good agreement with the computer simulation result for the Ar-Kr mixture. The mass dependence of shear viscosity for different mole fraction shows that deviation from ideal linear model comes even from mass difference in two species of fluid mixture. At higher mass ratio shear viscosity of mixture is not explained by any of the emperical model.

  14. Problems pilots face involving wind shear

    Science.gov (United States)

    Melvin, W. W.

    1977-01-01

    Educating pilots and the aviation industry about wind shears presents a major problem associated with this meteorological phenomenon. The pilot's second most pressing problem is the need for a language to discuss wind shear encounters with other pilots so that the reaction of the aircraft to the wind shear encounter can be accurately described. Another problem is the flight director which gives a centered pitch command for a given angular displacement from the glide slope. It was suggested that they should instead be called flight path command and should not center unless the aircraft is actually correcting to the flight path.

  15. Assessing the environmental impacts of soil compaction in Life Cycle Assessment.

    Science.gov (United States)

    Stoessel, Franziska; Sonderegger, Thomas; Bayer, Peter; Hellweg, Stefanie

    2018-02-27

    Maintaining biotic capacity is of key importance with regard to global food and biomass provision. One reason for productivity loss is soil compaction. In this paper, we use a statistical empirical model to assess long-term yield losses through soil compaction in a regionalized manner, with global coverage and for different agricultural production systems. To facilitate the application of the model, we provide an extensive dataset including crop production data (with 81 crops and corresponding production systems), related machinery application, as well as regionalized soil texture and soil moisture data. Yield loss is modeled for different levels of soil depth (0-25cm, 25-40cm and >40cm depth). This is of particular relevance since compaction in topsoil is classified as reversible in the short term (approximately four years), while recovery of subsoil layers takes much longer. We derive characterization factors quantifying the future average annual yield loss as a fraction of the current yield for 100years and applicable in Life Cycle Assessment studies of agricultural production. The results show that crops requiring enhanced machinery inputs, such as potatoes, have a major influence on soil compaction and yield losses, while differences between mechanized production systems (organic and integrated production) are small. The spatial variations of soil moisture and clay content are reflected in the results showing global hotspot regions especially susceptible to soil compaction, e.g. the South of Brazil, the Caribbean Islands, Central Africa, and the Maharashtra district of India. The impacts of soil compaction can be substantial, with highest annual yield losses in the range of 0.5% (95% percentile) due to one year of potato production (cumulated over 100y this corresponds to a one-time loss of 50% of the present yield). These modeling results demonstrate the necessity for including soil compaction effects in Life Cycle Impact Assessment. Copyright © 2018

  16. Compact Ceramic Microchannel Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Lewinsohn, Charles [Ceramatec, Inc., Salt Lake City, UT (United States)

    2016-10-31

    The objective of the proposed work was to demonstrate the feasibility of a step change in power plant efficiency at a commercially viable cost, by obtaining performance data for prototype, compact, ceramic microchannel heat exchangers. By performing the tasks described in the initial proposal, all of the milestones were met. The work performed will advance the technology from Technology Readiness Level 3 (TRL 3) to Technology Readiness Level 4 (TRL 4) and validate the potential of using these heat exchangers for enabling high efficiency solid oxide fuel cell (SOFC) or high-temperature turbine-based power plants. The attached report will describe how this objective was met. In collaboration with The Colorado School of Mines (CSM), specifications were developed for a high temperature heat exchanger for three commercial microturbines. Microturbines were selected because they are a more mature commercial technology than SOFC, they are a low-volume and high-value target for market entry of high-temperature heat exchangers, and they are essentially scaled-down versions of turbines used in utility-scale power plants. Using these specifications, microchannel dimensions were selected to meet the performance requirements. Ceramic plates were fabricated with microchannels of these dimensions. The plates were tested at room temperature and elevated temperature. Plates were joined together to make modular, heat exchanger stacks that were tested at a variety of temperatures and flow rates. Although gas flow rates equivalent to those in microturbines could not be achieved in the laboratory environment, the results showed expected efficiencies, robust operation under significant temperature gradients at high temperature, and the ability to cycle the stacks. Details of the methods and results are presented in this final report.

  17. Ion diffusion in compacted bentonite

    International Nuclear Information System (INIS)

    Lehikoinen, J.

    1999-03-01

    In the study, a two-dimensional molecular-level diffusion model, based on a modified form of the Gouy-Chapman (GC) theory of the electrical double layers, for hydrated ionic species in compacted bentonite was developed. The modifications to the GC theory, which forms the very kernel of the diffusion model, stem from various non-conventional features: ionic hydration, dielectric saturation, finite ion-sizes and specific adsorption. The principal objectives of the study were met. With the aid of the consistent diffusion model, it is a relatively simple matter to explain the experimentally observed macroscopic exclusion for anions as well as the postulated, but greatly controversial, surface diffusion for cations. From purely theoretical grounds, it was possible to show that the apparent diffusivities of cations, anions and neutral molecules (i) do not exhibit order-or-magnitude differences, and (ii) are practically independent of the solution ionic strength used and, consequently, of the distribution coefficient, K d , unless they experience specific binding onto the substrate surface. It was also of interest to investigate the equilibrium anionic concentration distribution in the pore geometry of the GMM model as a function of the solution ionic strength, and to briefly speculate its consequences to diffusion. An explicit account of the filter-plate effect was taken by developing a computerised macroscopic diffusion model, which is based upon the very robust and efficient Laplace Transform Finite-Difference technique. Finally, the inherent limitations as well as the potential fields of applications of the models were addressed. (orig.)

  18. Common fixed point theorems for left reversible and near-commutative semigroups and applications

    Directory of Open Access Journals (Sweden)

    Kang Shin Min

    2005-01-01

    Full Text Available We prove some common fixed point theorems for left reversible and near-commutative semigroups in compact and complete metric spaces, respectively. As applications, we get the existence and uniqueness of solutions for a class of nonlinear Volterra integral equations.

  19. Random attractors for stochastic lattice reversible Gray-Scott systems with additive noise

    Directory of Open Access Journals (Sweden)

    Hongyan Li

    2015-10-01

    Full Text Available In this article, we prove the existence of a random attractor of the stochastic three-component reversible Gray-Scott system on infinite lattice with additive noise. We use a transformation of addition involved with Ornstein-Uhlenbeck process, for proving the pullback absorbing property and the pullback asymptotic compactness of the reaction diffusion system with cubic nonlinearity.

  20. Diagnostics for the National Compact Stellarator Experiment

    International Nuclear Information System (INIS)

    Stratton, B.C.; Johnson, D.; Feder, R.; Fredrickson, E.; Neilson, H.; Takahashi, H.; Zarnstorf, M.; Cole, M.; Goranson, P.; Lazarus, E.; Nelson, B.

    2003-01-01

    The status of planning of the National Compact Stellarator Experiment (NCSX) diagnostics is presented, with the emphasis on resolution of diagnostics access issues and on diagnostics required for the early phases of operation

  1. New geometrical compactness measures for zones design

    Directory of Open Access Journals (Sweden)

    Eric Alfredo Rincón-García

    2012-07-01

    Full Text Available The design of compact zones has been studied because of its influence in the creation of zones with regular forms, which are easier to analyze, to investigate or to administer. This paper propose a new method to measure compactness,by means of the transformation of the original geographical spaces, into figures formed with square cells, which are used to measure the similarity between the original zone and an ideal zone with straight forms. The proposed method was applied to design electoral zones, which must satisfy constraints of compactness, contiguity and population balance, in a topographical configuration that favors the creation of twisted and diffuse shapes. The results show that the new method favors the creation of zones with straight forms, without an important effect to the population balance, which are considered zones of high quality. Keywords: Redistricting, compactness, simulated annealing, GIS. Mathematics Subject Classification: 90C59, 90C29, 68T20.

  2. Compact 2 Micron Seed Laser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for the development of new compact, high power and extremely reliable 2 micron seed laser using newly developed Tm3+ doped germanate glass fibers,...

  3. Compact 2 Micron Seed Laser, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for the development of innovative compact, high power and extremely reliable 2 micron seed laser using newly developed Tm3+ doped germanate glass...

  4. Gamma-Rays from Galactic Compact Sources

    Science.gov (United States)

    Kaaret, Philip

    2007-04-01

    Recent discoveries have revealed many sources of TeV photons in our Mikly Way galaxy powered by compact objects, either neutron stars or black holes. These objects must be powerful particle accelerators, some with peak energies of at least 100 TeV, and may be neutrino, as well as photon, sources. Future TeV observations will enable us to address key questions concerning particle acceleration by compact objects including the fraction of energy which accreting black holes channel into relativstic jet production, whether the compact object jets are leptonic or hadronic, and the mechanism by which pulsar winds accelerate relativistic particles. We report on work done related to compact Galactic objects in preparation of a White Paper on the status and future of ground-based gamma-ray astronomy requested by the Division of Astrophysics of the American Physical Society.

  5. Compact Positron Tomograph for Prostate Imaging

    National Research Council Canada - National Science Library

    Huber, Jennifer S

    2005-01-01

    The goal of this project is to construct a functioning compact positron tomograph, whose geometry is optimized for detecting prostate tumors with molecular tracers such as 11Ccholine (carbon-11 choline...

  6. Compact Positron Tomograph for Prostate Imaging

    National Research Council Canada - National Science Library

    Huber, Jennifer

    2004-01-01

    The goal of this project is to construct a functioning compact positron tomograph, whose geometry is optimized for detecting prostate tumors with molecular tracers such as 11Ccholine (carbon-11 choline...

  7. Compact Positron Tomograph for Prostate Imaging

    National Research Council Canada - National Science Library

    Derenzo, Stephen

    2003-01-01

    The goal of this project is to construct a functioning compact positron tomography, whose geometry is optimized for detecting prostate tumors with molecular tracers such as 11Ccholine (carbon-11 choline...

  8. Compact Microtube Igniter for Methane Rockets

    Data.gov (United States)

    National Aeronautics and Space Administration — This project seeks to facilitate the Evolvable Mars Campaign (EMC) LOX/Methane Propulsion Architecture by developing a reliable, compact, low power methane igniter....

  9. Compact Energy Conversion Module, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This STTR project delivers a compact vibration-based Energy Conversion Module (ECM) that powers sensors for purposes such as structural health monitoring (SHM). NASA...

  10. Compact energy conversion module, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This STTR project delivers a compact vibration-based Energy Conversion Module (ECM) that powers sensors for purposes like structural health monitoring (SHM). NASA...

  11. Compact, Airborne Multispecies Sensor, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The Small Business Innovative Research Phase I proposal seeks to develop a compact mid-infrared laser spectrometer to benefit Earth science research activities. To...

  12. Effect of Subsoil Compaction on Hydraulic Parameters

    DEFF Research Database (Denmark)

    Iversen, Bo Vangsø; Berisso, Feto Esimo; Schjønning, Per

    effects of subsoil compaction on soil ecological services and functions) put forward the hypothesis that due to a decrease in the hydraulic conductivity in the soil matrix, compaction increases the frequency of preferential flow events in macropores and therefore increases the leaching of otherwise....... In the field the near-saturated hydraulic conductivity was measured with a tension infiltrometer in the same treatments at a depth of 30 cm. In the laboratory saturated and near-saturated hydraulic conductivity and the bulk density were measured as well. Also, macropores in the large soil cores were made...... that for the upper soil depth, a significant increase in bulk density was measured for the compacted treatment. For the lower depth differences were less pronounced. For the saturated hydraulic conductivity, the results indicated a decrease of the hydraulic conductivity for the compacted treatment for the upper...

  13. Compact variable rate laser for space application

    Data.gov (United States)

    National Aeronautics and Space Administration — We will focus on the development and test of high reliable, radiation tolerant, compact laser for planetary mission.  The laser will be able to operate at variable...

  14. The Compact Pulsed Hadron Source Construction Status

    CERN Document Server

    Wei, Jie; Cai, Jinchi; Chen, Huaibi; Cheng, Cheng; Du, Qiang; Du, Taibin; Feng, Qixi; Feng, Zhe; Gong, Hui; Guan, Xialing; Han, Xiaoxue; Huang, Tuchen; Huang, Zhifeng; Li, Renkai; Li, Wenqian; Loong, Chun-Keung; Tang, Chuanxiang; Tian, Yang; Wang, Xuewu; Xie, Xiaofeng; Xing, Qingzi; Xiong, Zhengfeng; Xu, Dong; Yang, Yigang; Zeng, Zhi; Zhang, Huayi; Zhang, Xiaozhang; Zheng, Shu-xin; Zheng, Zhihong; Zhong, Bin; Billen, James; Young, Lloyd; Fu, Shinian; Tao, Juzhou; Zhao, Yaliang; Guan, Weiqiang; He, Yu; Li, Guohua; Li, Jian; Zhang, Dong-sheng; Li, Jinghai; Liang, Tianjiao; Liu, Zhanwen; Sun, Liangting; Zhao, Hongwei; Shao, Beibei; Stovall, James

    2010-01-01

    This paper reports the design and construction status, technical challenges, and future perspectives of the proton-linac based Compact Pulsed Hadron Source (CPHS) at the Tsinghua University, Beijing, China

  15. Mappings with closed range and compactness

    International Nuclear Information System (INIS)

    Iyahen, S.O.; Umweni, I.

    1985-12-01

    The motivation for this note is the result of E.O. Thorp that a normed linear space E is finite dimensional if and only if every continuous linear map for E into any normed linear space has a closed range. Here, a class of Hausdorff topological groups is introduced; called r-compactifiable topological groups, they include compact groups, locally compact Abelian groups and locally convex linear topological spaces. It is proved that a group in this class which is separable, complete metrizable or locally compact, is necessarily compact if its image by a continuous group homomorphism is necessarily closed. It is deduced then that a Hausdorff locally convex is zero if its image by a continuous additive map is necessarily closed. (author)

  16. Deep Compaction Control of Sandy Soils

    Directory of Open Access Journals (Sweden)

    Bałachowski Lech

    2015-02-01

    Full Text Available Vibroflotation, vibratory compaction, micro-blasting or heavy tamping are typical improvement methods for the cohesionless deposits of high thickness. The complex mechanism of deep soil compaction is related to void ratio decrease with grain rearrangements, lateral stress increase, prestressing effect of certain number of load cycles, water pressure dissipation, aging and other effects. Calibration chamber based interpretation of CPTU/DMT can be used to take into account vertical and horizontal stress and void ratio effects. Some examples of interpretation of soundings in pre-treated and compacted sands are given. Some acceptance criteria for compaction control are discussed. The improvement factors are analysed including the normalised approach based on the soil behaviour type index.

  17. Controlled Compact High Voltage Power Lines

    Directory of Open Access Journals (Sweden)

    Postolati V.

    2016-04-01

    Full Text Available Nowadays modern overhead transmission lines (OHL constructions having several significant differences from conventional ones are being used in power grids more and more widely. Implementation of compact overhead lines equipped with FACTS devices, including phase angle regulator settings (compact controlled OHL, appears to be one of the most effective ways of power grid development. Compact controlled AC HV OHL represent a new generation of power transmission lines embodying recent advanced achievements in design solutions, including towers and insulation, together with interconnection schemes and control systems. Results of comprehensive research and development in relation to 110–500kV compact controlled power transmission lines together with theoretical basis, substantiation, and methodological approaches to their practical application are presented in the present paper.

  18. Compact Fiber Lasers for Coherent LIDAR Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This is a proposal to investigate the feasibility of developing a low cost, compact, lightweight, high power (>500m W) and narrow linewidth 1.5 and 1.06 micron...

  19. Impact Compaction of a Granular Material

    Science.gov (United States)

    Fenton, Gregg; Asay, Blaine; Todd, Steve; Grady, Dennis

    2017-06-01

    The dynamic behavior of granular materials has importance to a variety of engineering applications. Although, the mechanical behavior of granular materials have been studied extensively for several decades, the dynamic behavior of these materials remains poorly understood. High-quality experimental data are needed to improve our general understanding of granular material compaction physics. This paper describes how an instrumented plunger impact system can be used to measure the compaction process for granular materials at high and controlled strain rates and subsequently used for computational modelling. The experimental technique relies on a gas-gun driven plunger system to generate a compaction wave through a volume of granular material. This volume of material has been redundantly instrumented along the bed length to track the progression of the compaction wave, and the piston displacement is measured with Photon Doppler Velocimetry (PDV). Using the gathered experimental data along with the initial material tap density, a granular material equation of state can be determined.

  20. Steady state compact toroidal plasma production

    Science.gov (United States)

    Turner, William C.

    1986-01-01

    Apparatus and method for maintaining steady state compact toroidal plasmas. A compact toroidal plasma is formed by a magnetized coaxial plasma gun and held in close proximity to the gun electrodes by applied magnetic fields or magnetic fields produced by image currents in conducting walls. Voltage supply means maintains a constant potential across the electrodes producing an increasing magnetic helicity which drives the plasma away from a minimum energy state. The plasma globally relaxes to a new minimum energy state, conserving helicity according to Taylor's relaxation hypothesis, and injecting net helicity into the core of the compact toroidal plasma. Controlling the voltage so as to inject net helicity at a predetermined rate based on dissipative processes maintains or increases the compact toroidal plasma in a time averaged steady state mode.

  1. Shear wavelength estimation based on inverse filtering and multiple-point shear wave generation

    Science.gov (United States)

    Kitazaki, Tomoaki; Kondo, Kengo; Yamakawa, Makoto; Shiina, Tsuyoshi

    2016-07-01

    Elastography provides important diagnostic information because tissue elasticity is related to pathological conditions. For example, in a mammary gland, higher grade malignancies yield harder tumors. Estimating shear wave speed enables the quantification of tissue elasticity imaging using time-of-flight. However, time-of-flight measurement is based on an assumption about the propagation direction of a shear wave which is highly affected by reflection and refraction, and thus might cause an artifact. An alternative elasticity estimation approach based on shear wavelength was proposed and applied to passive configurations. To determine the elasticity of tissue more quickly and more accurately, we proposed a new method for shear wave elasticity imaging that combines the shear wavelength approach and inverse filtering with multiple shear wave sources induced by acoustic radiation force (ARF). The feasibility of the proposed method was verified using an elasticity phantom with a hard inclusion.

  2. Turbulent shear layers in confining channels

    Science.gov (United States)

    Benham, Graham; Castrejon-Pita, Alfonso; Hewitt, Ian; Please, Colin; Style, Rob; Bird, Paul

    2017-11-01

    The development of shear layers are ubiquitous in a wide range of situations, from diffusers, nozzles, turbines and ducts to urban air flow and geophysical flows. In this talk we present a simple model for the development of shear layers between flows that mix in confining channels. The model, comprising two plug flow regions separated by a linear shear layer, shows good agreement with both laboratory experiments and computational turbulence modelling (at a fraction of the computation time). Such efficient models, capable of capturing and exhibiting the main characteristics of the turbulent shear layers, are expected to be useful for both modelling and design purposes. We demonstrate the latter by showing how the model can be utilised to optimise pressure recovery in diffusers with non-uniform inflows. EPSRC Centre for Doctoral Training in Industrially Focused Mathematical Modelling, VerdErg Renewable Energy Limited, John Fell Fund (Oxford University Press).

  3. Localization in inelastic rate dependent shearing deformations

    KAUST Repository

    Katsaounis, Theodoros

    2016-09-18

    Metals deformed at high strain rates can exhibit failure through formation of shear bands, a phenomenon often attributed to Hadamard instability and localization of the strain into an emerging coherent structure. We verify formation of shear bands for a nonlinear model exhibiting strain softening and strain rate sensitivity. The effects of strain softening and strain rate sensitivity are first assessed by linearized analysis, indicating that the combined effect leads to Turing instability. For the nonlinear model a class of self-similar solutions is constructed, that depicts a coherent localizing structure and the formation of a shear band. This solution is associated to a heteroclinic orbit of a dynamical system. The orbit is constructed numerically and yields explicit shear localizing solutions. © 2016 Elsevier Ltd

  4. Electrostatic ion cyclotron velocity shear instability

    Science.gov (United States)

    Lemons, D. S.; Winske, D.; Gary, S. P.

    1992-01-01

    A local electrostatic dispersion equation is derived for a shear flow perpendicular to an ambient magnetic field, which includes all kinetic effects and involves only one important parameter. The dispersion equation is cast in the form of Gordeyev integrals and is solved numerically. Numerical solutions indicate that an ion cyclotron instability is excited. The instability occurs roughly at multiples of the ion cyclotron frequency (modified by the shear), with the growth rate or the individual harmonics overlapping in the wavenumber. At large values of the shear parameter, the instability is confined to long wavelengths, but at smaller shear, a second distinct branch at shorter wavelengths also appears. The properties of the instability obtained are compared with those obtained in the nonlocal limit by Ganguli et al. (1985, 1988).

  5. Recent progress in shear punch testing

    International Nuclear Information System (INIS)

    Hamilton, M.L.; Toloczko, M.B.; Lucas, G.E.

    1994-09-01

    The shear punch test was developed in response to the needs of the materials development community for small-scale mechanical properties tests. Such tests will be of great importance when a fusion neutron simulation device is built, since such a device is expected to have a limited irradiation volume. The shear punch test blanks a circular disk from a fixed sheet metal specimen, specifically a TEM disk. Load-displacement data generated during the test can be related to uniaxial tensile properties such as yield and ultimate strength. Shear punch and tensile tests were performed at room temperature on a number of unirradiated aluminum, copper, vanadium, and stainless steel alloys and on several irradiated aluminum alloys. Recent results discussed here suggest that the relationship between shear punch strength and tensile strength varies with alloy class, although the relationship determined for the unirradiated condition remains valid for the irradiated aluminum alloys

  6. Shear strength of clay and silt embankments.

    Science.gov (United States)

    2009-09-01

    Highway embankment is one of the most common large-scale geotechnical facilities constructed in Ohio. In the past, the design of these embankments was largely based on soil shear strength properties that had been estimated from previously published e...

  7. Immiscible blend morphology after shear and elongation

    Science.gov (United States)

    Batch, Gibson L.; Trifkovic, Milana; Hedegaard, Aaron; Macosko, Christopher W.

    2015-05-01

    This work examines the role of shear and extensional strain on immiscible blend morphology, namely domain size, orientation, and co-continuity. The domain size reduces with surface tension similar to what is observed with isolated droplets. The domain size is shown to increase with shear strain due to coalescence. Hence the best mixing is found with low shear strains, i.e. low rates of shear and short durations of time. Extensional strain (extrusion draw ratio DR) reduces phase width and thickness with a DR-0.5 dependence, suggesting the transformation to a fibrilar morphology. The critical draw ratio for morphology transformation is approximately 7, in agreement with observations by Grace for droplet breakup in elongation. Fibrilar morphology is also consistent with a large increase in strain-to-break in the drawn film and with observed creep and optical scattering behavior.

  8. Recent progress in shear punch testing

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, M.L. [Pacific Northwest Lab., Richland, WA (United States); Toloczko, M.B.; Lucas, G.E. [Univ. of California, Santa Barbara, CA (United States)

    1994-09-01

    The shear punch test was developed in response to the needs of the materials development community for small-scale mechanical properties tests. Such tests will be of great importance when a fusion neutron simulation device is built, since such a device is expected to have a limited irradiation volume. The shear punch test blanks a circular disk from a fixed sheet metal specimen, specifically a TEM disk. Load-displacement data generated during the test can be related to uniaxial tensile properties such as yield and ultimate strength. Shear punch and tensile tests were performed at room temperature on a number of unirradiated aluminum, copper, vanadium, and stainless steel alloys and on several irradiated aluminum alloys. Recent results discussed here suggest that the relationship between shear punch strength and tensile strength varies with alloy class, although the relationship determined for the unirradiated condition remains valid for the irradiated aluminum alloys.

  9. 49 CFR 230.89 - Reverse gear.

    Science.gov (United States)

    2010-10-01

    ... Reversing Gear § 230.89 Reverse gear. (a) General provisions. Reverse gear, reverse levers, and quadrants shall be maintained in a safe and suitable condition for service. Reverse lever latch shall be so...

  10. Hydrogen sorption and permeability of compacted LiBH4 nanoconfined into activated carbon nanofibers impregnated with TiO2

    Science.gov (United States)

    Sitthiwet, Chongsutthamani; Thiangviriya, Sophida; Thaweelap, Natthaporn; Meethom, Sukanya; Kaewsuwan, Dechmongkhon; Chanlek, Narong; Utke, Rapee

    2017-11-01

    Activated carbon nanofibers impregnated with titanium (IV) oxide (TiO2), denoted as ACNF-Ti are prepared by carbonization and activation of electrospun nanofibers of polyacrylonitrile (PAN)-titanium (IV) isopropoxide composite. Pristine LiBH4 and nanoconfined LiBH4 in ACNF-Ti, denoted as LiBH4-ACNF-Ti are compacted under the pressures of 434 and 868 MPa. Dehydrogenation temperature of compacted LiBH4 increases (up to 485 °C) with compaction pressure due to poor hydrogen permeability. In the case of compacted LiBH4-ACNF-Ti, major dehydrogenation temperature at 352-359 °C and hydrogen content liberated (74-76% of theoretical capacity) are obtained despite enhanced compaction pressure. Mechanical stability during cycling of compacted LiBH4-ACNF-Ti is achieved. Although hydrogen permeability of compacted LiBH4-ACNF-Ti improves with enhanced compaction pressure, detrimental kinetics and reversibility are detected. Since the fibrous structure of ACNF-Ti are brittle, the broken and/or shorten fibers are observed after compaction under high pressure. The latter results in not only inferior nanoconfinement of LiBH4 into ACNF-Ti, but also agglomeration of hydride materials upon cycling.

  11. Thermodynamics of dilute gases in shear flow

    Science.gov (United States)

    Jou, D.; Criado-Sancho, M.

    2001-03-01

    We consider the effect of shear and normal viscous pressures on the non-equilibrium entropy of ideal gases in Couette flow. These results extend the previous ones (Bidar et al., Physica A 233 (1996) 163), where normal pressure effects were ignored. Furthermore, we analyze the non-equilibrium contributions to the chemical potential, which may be useful in the analysis of shear-induced effects on colligative properties and chemical equilibrium.

  12. Hydrodynamical fluctuations in smooth shear flows

    International Nuclear Information System (INIS)

    Chagelishvili, G.D.; Khujadze, G.R.; Lominadze, J.G.

    1999-11-01

    Background of hydrodynamical fluctuations in a intrinsically/stochastically forced, laminar, uniform shear flow is studied. The employment of so-called nonmodal mathematical analysis makes it possible to represent the background of fluctuations in a new light and to get more insight into the physics of its formation. The basic physical processes responsible for the formation of vortex and acoustic wave fluctuation backgrounds are analyzed. Interplay of the processes at low and moderate shear rates is described. Three-dimensional vortex fluctuations around a given macroscopic state are numerically calculated. The correlation functions of the fluctuations of physical quantities are analyzed. It is shown that there exists subspace D k in the wave-number space (k-space) that is limited externally by spherical surface with radius k ν ≡ A/ν (where A is the velocity shear parameter, ν - the kinematic viscosity) in the nonequilibrium open system under study. The spatial Fourier harmonics of vortex as well as acoustic wave fluctuations are strongly subjected by flow shear (by the open character of the system) at wave-numbers satisfying the condition k ν . Specifically it is shown that in D k : The fluctuations are non-Markovian; the spatial spectral density of energy of the vortex fluctuations by far exceeds the white-noise; the term of a new type associated to the hydrodynamical fluctuation of velocity appears in the correlation function of pressure; the fluctuation background of the acoustic waves is completely different at low and moderate shear rates (at low shear rates it is reduced in D k in comparison to the uniform (non-shear) flow; at moderate shear rates it it comparable to the background of the vortex fluctuations). The fluctuation background of both the vortex and the acoustic wave modes is anisotropic. The possible significance of the fluctuation background of vortices for the subcritical transition to turbulence and Brownian motion of small macroscopic

  13. Modeling and implementation of wind shear data

    Science.gov (United States)

    Frost, Walter

    1987-01-01

    The problems of implementing the JAWS wind shear data are discussed. The data sets are described from the view of utilizing them in an aircraft performance computer program. Then, some of the problems of nonstandard procedures are described in terms of programming the equations of aircraft motion when the effects of temporal and spatially variable winds are included. Finally, some of the computed effects of the various wind shear terms are shown.

  14. Assessment of Shear Strength in Silty Soils

    Directory of Open Access Journals (Sweden)

    Stefaniak Katarzyna

    2015-06-01

    Full Text Available The article presents a comparison of shear strength values in silty soils from the area of Poznań, determined based on selected Nkt values recommended in literature, with values of shear strength established on the basis of Nkt values recommended by the author. Analysed silty soils are characterized by the carbonate cementation zone, which made it possible to compare selected empirical coefficients both in normally consolidated and overconsolidated soils

  15. Speckle Shearing Interferometry And Its Application

    Science.gov (United States)

    Jingtang, Ke; Hongqing, Zhang; Yeling, He; Yanfu, Chang

    1983-12-01

    The paper deals with experiments made to verify the theory of bending of plates and related problems by method of speckle shearing interferometry, which is proved to be highly sensitive. Tests carried out on rubber products: (such as tires)and thin-walled containers have demonstrated the prospects of using image-shearing camera in nondestructive in-situ testing of industrial products, suggesting a potentiality still wider than that of holographic interferometry.

  16. Experimental study of shear rate dependence in perpetually sheared granular matter

    Science.gov (United States)

    Liu, Sophie Yang; Guillard, François; Marks, Benjy; Rognon, Pierre; Einav, Itai

    2017-06-01

    We study the shear behaviour of various granular materials by conducting novel perpetual simple shear experiments over four orders of magnitude of relatively low shear rates. The newly developed experimental apparatus employed is called "3D Stadium Shear Device" which is an extended version of the 2D Stadium Shear Device [1]. This device is able to provide a non-radial dependent perpetual shear flow and a nearly linear velocity profile between two oppositely moving shear walls. Using this device, we are able to test a large variety of granular materials. Here, we demonstrate the applicability of the device on glass beads (diameter 1 mm, 3 mm, and 14 mm) and rice. We particularly focus on studying these materials at very low inertial number I ranging from 10-6 to 10-2. We find that, within this range of I, the friction coefficient μ of glass beads has no shear rate dependence. A particularly appealing observation comes from testing rice, where the attainment of critical state develops under much longer duration than in other materials. Initially during shear we find a value of μ similar to that found for glass beads, but with time this value decreases gradually towards the asymptotic critical state value. The reason, we believe, lies in the fact that rice grains are strongly elongated; hence the time to achieve the stable μ is primarily controlled by the time for particles to align themselves with respect to the shear walls. Furthermore, the initial packing conditions of samples also plays a role in the evolution of μ when the shear strain is small, but that impact will eventually be erased after sufficient shear strain.

  17. Experimental study of shear rate dependence in perpetually sheared granular matter

    Directory of Open Access Journals (Sweden)

    Liu Sophie Yang

    2017-01-01

    Full Text Available We study the shear behaviour of various granular materials by conducting novel perpetual simple shear experiments over four orders of magnitude of relatively low shear rates. The newly developed experimental apparatus employed is called “3D Stadium Shear Device” which is an extended version of the 2D Stadium Shear Device [1]. This device is able to provide a non-radial dependent perpetual shear flow and a nearly linear velocity profile between two oppositely moving shear walls. Using this device, we are able to test a large variety of granular materials. Here, we demonstrate the applicability of the device on glass beads (diameter 1 mm, 3 mm, and 14 mm and rice. We particularly focus on studying these materials at very low inertial number I ranging from 10−6 to 10−2. We find that, within this range of I, the friction coefficient μ of glass beads has no shear rate dependence. A particularly appealing observation comes from testing rice, where the attainment of critical state develops under much longer duration than in other materials. Initially during shear we find a value of μ similar to that found for glass beads, but with time this value decreases gradually towards the asymptotic critical state value. The reason, we believe, lies in the fact that rice grains are strongly elongated; hence the time to achieve the stable μ is primarily controlled by the time for particles to align themselves with respect to the shear walls. Furthermore, the initial packing conditions of samples also plays a role in the evolution of μ when the shear strain is small, but that impact will eventually be erased after sufficient shear strain.

  18. Posterior Reversible Encephalopathy (PRES)

    International Nuclear Information System (INIS)

    Moron E, Fanny E; Diaz Marchan, Pedro

    2005-01-01

    The Posterior Reversible Encephalopathy Syndrome (PRES) is a clinical Syndrome composed of cephalea, alteration in vision and convulsions, usually observed in patients with sudden elevation of arterial pressure. The imagenologic evidence shows reversible vasogenic brain edema without stroke. Its location is predominantly posterior; it affects the cortex and the subcortical white matter of the occipital, parietal and temporal lobes. The treatment with antihypertensive drugs and the removing of immunosupressor medication are generally associated with complete neurological recovery; this is reflected also in the images which return to their basal condition. The untreated hypertension, on the other side, can result in a progressive defect of the autoregulation system of the central nervous system with cerebral hemorrhage, irreversible brain stroke, coma and death

  19. Compaction of spent nuclear fuel cans

    International Nuclear Information System (INIS)

    Sullivan, H.

    1985-01-01

    Hydraulic press apparatus for compacting waste material eg. spent nuclear fuel cans comprises a fixed frame, a movable cross head, a press crown and three groups of piston/cylinder devices; having their pistons connected to the cross head and their cylinders secured to the press crown. A control means connects the first group of devices to hydraulic fluid in a reservoir which is pressurised initially by gas from gas accumulators to move the cross head and a quill secured thereto towards the frame base to compact the waste at a first high rate under a first high loading. Compaction then proceeds at a lower second rate at a lower second loading as the hydraulic fluid in the reservoir is pressurised by a pump. At two subsequent stages of compaction of the waste at which resistance increases causing a pressure rise in cylinders the control means causes hydraulic fluid to be passed to the second group of devices and thence to the third group of devices, the compaction rate reducing at each stage but the compaction force increasing. (author)

  20. Technology Selections for Cylindrical Compact Fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey A. Phillips

    2010-10-01

    A variety of process approaches are available and have been used historically for manufacture of cylindrical fuel compacts. The jet milling, fluid bed overcoating, and hot press compacting approach being adopted in the U.S. AGR Fuel Development Program for scale-up of the compacting process involves significant paradigm shifts from historical approaches. New methods are being pursued because of distinct advantages in simplicity, yield, and elimination of process mixed waste. Recent advances in jet milling technology allow simplified dry matrix powder preparation. The matrix preparation method is well matched with patented fluid bed powder overcoating technology recently developed for the pharmaceutical industry and directly usable for high density fuel particle matrix overcoating. High density overcoating places fuel particles as close as possible to their final position in the compact and is matched with hot press compacting which fully fluidizes matrix resin to achieve die fill at low compacting pressures and without matrix end caps. Overall the revised methodology provides a simpler process that should provide very high yields, improve homogeneity, further reduce defect fractions, eliminate intermediate grading and QC steps, and allow further increases in fuel packing fractions.

  1. The impact of soil compaction on runoff

    Science.gov (United States)

    Rogger, Magdalena; Blöschl, Günter

    2017-04-01

    Soil compaction caused by intensive agricultural practices is known to influence runoff processes at the local scale and is often speculated to have an impact on flood events at much larger scales. Due to the complex and diverse mechanisms related to soil compaction, the key processes influencing runoff at different scales are still poorly understood. In this study we are analyzing data from a subsoil compaction database [Trautner et al., 2003] that includes the results of a large number of field and laboratory experiments across Europe. We are focusing on changes in parameters relevant for hydrology such as saturated hydraulic conductivity and bulk density. We will compare the observed impacts in relation to climatic and soil conditions. The specific type of agricultural practice causing the soil compaction is also taken into account. In a further step the results of this study shall be used to derive a toy model for scenario analysis in order to identify the potential impacts of soil compaction on runoff processes at larger scales then the plot scale. Reference : Trautner, A., Van den Akker, J.J.H., Fleige, H, Arvidsson, J. and Horn, R., 2003. A subsoil compaction database: its development, structure and content. Soil & Till. Res. 73: 9-13.

  2. Time-reversal and Bayesian inversion

    Science.gov (United States)

    Debski, Wojciech

    2017-04-01

    Probabilistic inversion technique is superior to the classical optimization-based approach in all but one aspects. It requires quite exhaustive computations which prohibit its use in huge size inverse problems like global seismic tomography or waveform inversion to name a few. The advantages of the approach are, however, so appealing that there is an ongoing continuous afford to make the large inverse task as mentioned above manageable with the probabilistic inverse approach. One of the perspective possibility to achieve this goal relays on exploring the internal symmetry of the seismological modeling problems in hand - a time reversal and reciprocity invariance. This two basic properties of the elastic wave equation when incorporating into the probabilistic inversion schemata open a new horizons for Bayesian inversion. In this presentation we discuss the time reversal symmetry property, its mathematical aspects and propose how to combine it with the probabilistic inverse theory into a compact, fast inversion algorithm. We illustrate the proposed idea with the newly developed location algorithm TRMLOC and discuss its efficiency when applied to mining induced seismic data.

  3. Global Stability of the Field Reversed Configuration

    International Nuclear Information System (INIS)

    Belova, E.V.; Jardin, S.C.; Ji, H.; Kulsrud, R.M.; Park, W.; Yamada, M.

    2000-01-01

    New computational results are presented which provide a theoretical basis for the stability of the Field Reversed Configuration (FRC). The FRC is a compact toroid with negligible toroidal field in which the plasma is confined by a poloidal magnetic field associated with toroidal diamagnetic current. Although many MHD modes are predicted to be unstable, FRCs have been produced successfully by several formation techniques and show surprising macroscopic resilience. In order to understand this discrepancy, we have developed a new 3D nonlinear hybrid code (kinetic ions and fluid electrons), M3D-B, which is used to study the role of kinetic effects on the n = 1 tilt and higher n modes in the FRC. Our simulations show that there is a reduction in the tilt mode growth rate in the kinetic regime, but no absolute stabilization has been found for s bar less than or approximately equal to 1, where s bar is the approximate number of ion gyroradii between the field null and the separatrix. However, at low values of s bar, the instabilities saturate nonlinearly through a combination of a lengthening of the initial equilibrium and a modification of the ion distribution function. These saturated states persist for many Alfven times, maintaining field reversal

  4. A new look on blood shear thinning

    Science.gov (United States)

    Abkarian, Manouk; Lanotte, Luca; Fromental, Jean-Marc; Mendez, Simon; Fedosov, Dmitry; Gompper, Gerhard; Mauer, Johannes; Claveria, Viviana

    2015-11-01

    Blood is a shear-thinning fluid. At shear rates γ˙ cells (RBCs). For higher γ˙ in the range 10 - 1000 s-1 , where RBCs flow as single elements, studies demonstrated that RBCs suspended in a viscous fluid mimicking the viscosity of whole blood, deformed into ellipsoids aligned steadily in the direction of the flow, while their membrane rotated about their center of mass like a tank-tread. Such drop-like behavior seemed to explain shear-thinning. Here, using rheometers, microfluidics and simulations, we show that the dynamics of single RBCs in plasma-like fluids display a different sequence of deformation for increasing shear rates going from discocytes to successively, stomatocytes, folded stomatocytes, trilobes and tetralobes, but never ellipsoids. This result is also identical for physiological hematocrits. We correlate this shape diagram to the different regimes in blood rheology for high shear rates and propose a new-look on the interpretation of blood shear-thinning behavior.

  5. Cosmology with cosmic shear observations: a review.

    Science.gov (United States)

    Kilbinger, Martin

    2015-07-01

    Cosmic shear is the distortion of images of distant galaxies due to weak gravitational lensing by the large-scale structure in the Universe. Such images are coherently deformed by the tidal field of matter inhomogeneities along the line of sight. By measuring galaxy shape correlations, we can study the properties and evolution of structure on large scales as well as the geometry of the Universe. Thus, cosmic shear has become a powerful probe into the nature of dark matter and the origin of the current accelerated expansion of the Universe. Over the last years, cosmic shear has evolved into a reliable and robust cosmological probe, providing measurements of the expansion history of the Universe and the growth of its structure. We review here the principles of weak gravitational lensing and show how cosmic shear is interpreted in a cosmological context. Then we give an overview of weak-lensing measurements, and present the main observational cosmic-shear results since it was discovered 15 years ago, as well as the implications for cosmology. We then conclude with an outlook on the various future surveys and missions, for which cosmic shear is one of the main science drivers, and discuss promising new weak cosmological lensing techniques for future observations.

  6. Shear induced structures in crystallizing cocoa butter

    Science.gov (United States)

    Mazzanti, Gianfranco; Guthrie, Sarah E.; Sirota, Eric B.; Marangoni, Alejandro G.; Idziak, Stefan H. J.

    2004-03-01

    Cocoa butter is the main structural component of chocolate and many cosmetics. It crystallizes in several polymorphs, called phases I to VI. We used Synchrotron X-ray diffraction to study the effect of shear on its crystallization. A previously unreported phase (phase X) was found and a crystallization path through phase IV under shear was observed. Samples were crystallized under shear from the melt in temperature controlled Couette cells, at final crystallization temperatures of 17.5^oC, 20^oC and 22.5^oC in Beamline X10A of NSLS. The formation of phase X was observed at low shear rates (90 s-1) and low crystallization temperature (17.5^oC), but was absent at high shear (720 s-1) and high temperature (20^oC). The d-spacing and melting point suggest that this new phase is a mixture rich on two of the three major components of cocoa butter. We also found that, contrary to previous reports, the transition from phase II to phase V can happen through the intermediate phase IV, at high shear rates and temperature.

  7. Shear thinning in non-Brownian suspensions.

    Science.gov (United States)

    Chatté, Guillaume; Comtet, Jean; Niguès, Antoine; Bocquet, Lydéric; Siria, Alessandro; Ducouret, Guylaine; Lequeux, François; Lenoir, Nicolas; Ovarlez, Guillaume; Colin, Annie

    2018-02-14

    We study the flow of suspensions of non-Brownian particles dispersed into a Newtonian solvent. Combining capillary rheometry and conventional rheometry, we evidence a succession of two shear thinning regimes separated by a shear thickening one. Through X-ray radiography measurements, we show that during each of those regimes, the flow remains homogeneous and does not involve particle migration. Using a quartz-tuning fork based atomic force microscope, we measure the repulsive force profile and the microscopic friction coefficient μ between two particles immersed into the solvent, as a function of normal load. Coupling measurements from those three techniques, we propose that (1) the first shear-thinning regime at low shear rates occurs for a lubricated rheology and can be interpreted as a decrease of the effective volume fraction under increasing particle pressures, due to short-ranged repulsive forces and (2) the second shear thinning regime after the shear-thickening transition occurs for a frictional rheology and can be interpreted as stemming from a decrease of the microscopic friction coefficient at large normal load.

  8. Sobolev Spaces on Locally Compact Abelian Groups: Compact Embeddings and Local Spaces

    Directory of Open Access Journals (Sweden)

    Przemysław Górka

    2014-01-01

    Full Text Available We continue our research on Sobolev spaces on locally compact abelian (LCA groups motivated by our work on equations with infinitely many derivatives of interest for string theory and cosmology. In this paper, we focus on compact embedding results and we prove an analog for LCA groups of the classical Rellich lemma and of the Rellich-Kondrachov compactness theorem. Furthermore, we introduce Sobolev spaces on subsets of LCA groups and study its main properties, including the existence of compact embeddings into Lp-spaces.

  9. Time-reversal acoustics

    Energy Technology Data Exchange (ETDEWEB)

    Fink, Mathias [Laboratoire Ondes et Acoustique, Ecole Superieure de Physique et de Chimie Industrielle de la Ville de Paris, Universite Denis Diderot, UMR CNRS 7587, 10 Rue Vauquelin, 75005 Paris (France)], E-mail: mathias.fink@espci.fr

    2008-10-15

    Time-reversal mirrors (TRMs) refocus an incident acoustic field to the position of the original source regardless of the complexity of the propagation medium. TRM's have now been implemented in a variety of physical scenarios from MHz ultrasonics with order centimeter aperture size to hundreds/thousands of Hz in ocean acoustics with order hundred meter aperture size. Common to this broad range of scales is a remarkable robustness exemplified by observations at all scales that the more complex the medium between the probe source and the TRM, the sharper the focus. The relation between the medium complexity and the size of the focal spot is studied in this paper. It is certainly the most exciting property of TRM compared to standard focusing devices. A TRM acts as an antenna that uses complex environments to appears wider than it is, resulting for a broadband pulse in a refocusing quality that does not depend of the TRM aperture. In this paper, we investigate the time-reversal approach in various media of increasing complexity and we discuss the link existing between time-reversal approach and local helioseismology where Green's functions can be extracted from diffusive noise.

  10. Avulsive axillary artery injury in reverse total shoulder arthroplasty.

    Science.gov (United States)

    Wingert, Nathaniel C; Beck, John D; Harter, G Dean

    2014-01-01

    In addition to neurologic injuries such as peripheral nerve palsy, axillary vessel injury should be recognized as a possible complication of reverse total shoulder arthroplasty. Limb lengthening associated with Grammont-type reverse total shoulder arthroplasty places tension across the brachial plexus and axillary vessels and may contribute to observed injuries. The Grammont-type reverse total shoulder arthroplasty prosthesis reverses the shoulder ball and socket, shifts the shoulder center of rotation distal and medial, and lengthens the arm. This alteration of native anatomy converts shearing to compressive glenohumeral joint forces while augmenting and tensioning the deltoid lever arm. Joint stability is enhanced; shoulder elevation is enabled in the rotator cuff–deficient shoulder. Arm lengthening associated with reverse total shoulder arthroplasty places a longitudinal strain on the brachial plexus and axillary vessels. Peripheral nerve palsies and other neurologic complications of reverse total shoulder arthroplasty have been documented. The authors describe a patient with rotator cuff tear arthropathy and a history of radioulnar synostosis who underwent reverse total shoulder arthroplasty complicated by intraoperative injury to the axillary artery and postoperative radial, ulnar, and musculocutaneous nerve palsies. Following a seemingly unremarkable placement of reverse shoulder components, brisk arterial bleeding was encountered while approximating the incised subscapularis tendon in preparation for wound closure. Further exploration revealed an avulsive-type injury of the axillary artery. After an unsuccessful attempt at primary repair, a synthetic arterial bypass graft was placed. Reperfusion of the right upper extremity was achieved and has been maintained to date. Postoperative clinical examination and electromyographic studies confirmed ongoing radial, ulnar, and musculocutaneous neuropathies.

  11. Bond Strength between Hybrid Fiber-Reinforced Lightweight Aggregate Concrete Substrate and Self-Compacting Concrete as Topping Layer

    Directory of Open Access Journals (Sweden)

    Slamet Widodo

    2017-01-01

    Full Text Available Structural performance evaluation of composite concrete slabs that were constructed using partially precast concreting system which utilized Hybrid Fiber-Reinforced Lightweight Aggregate Concrete (HyFRLWAC as stay in-place formwork and self-compacting concrete (SCC as topping layer was conducted in this research. This paper focused on determining the appropriate strength limit criteria of interface between two different concrete layers. The tensile strength was tested using pull-off test, while concrete cohesion was investigated based on modified bisurface shear test, and dual L-shaped shear test was used to determine the effect of normal force on the shear strength of concrete interface. Sample variants were designed based on the substrate surface conditions, compressive strength of the topping layer, and magnitude of perpendicular normal force acting on interface area. The substrate surfaces were prepared in as-placed and grooved conditions for tensile test, cohesion, and shear strength test. Test results indicate that tensile strength, cohesion, and shear strength of the concrete interface are affected by surface condition of the substrate, compressive strength of the topping layer, and the normal force acting perpendicularly on the concrete interface area. Proposed formulation for bond strength prediction between HyFRLWAC as substrate and SCC as topping layer is also presented in this paper.

  12. Status of time reversal invariance

    International Nuclear Information System (INIS)

    Henley, E.M.

    1989-01-01

    Time Reversal Invariance is introduced, and theories for its violation are reviewed. The present experimental and theoretical status of Time Reversal Invariance and tests thereof will be presented. Possible future tests will be discussed

  13. Panel and planar experimental shear behavior of wood panels ...

    African Journals Online (AJOL)

    Panel and planar experimental shear behavior of wood panels laminated softwood oriented OSB conditioned at different environments. ... to that measured in the case of panel shear for different environments. Keywords : oriented strand board – panel shear strength- planar shear strength - environment – moisture content ...

  14. Evaluation of size dependent design shear strength of reinforced ...

    Indian Academy of Sciences (India)

    mate shear strengths of reinforced concrete (RC) beams without web reinforcement. The shear strength ... percentage of flexural reinforcement and depth of the beam constant) as (i) deep beams with 0. < a/d ≤ 1, (ii) ... the shear strength of deep beams when the shear span-to-depth ratio was 1.0 (Tan & Lu 1999;. Walraven ...

  15. Mesostructural investigation of micron-sized glass particles during shear deformation - An experimental approach vs. DEM simulation

    Science.gov (United States)

    Torbahn, Lutz; Weuster, Alexander; Handl, Lisa; Schmidt, Volker; Kwade, Arno; Wolf, Dietrich E.

    2017-06-01

    The interdependency of structure and mechanical features of a cohesive powder packing is on current scientific focus and far from being well understood. Although the Discrete Element Method provides a well applicable and widely used tool to model powder behavior, non-trivial contact mechanics of micron-sized particles demand a sophisticated contact model. Here, a direct comparison between experiment and simulation on a particle level offers a proper approach for model validation. However, the simulation of a full scale shear-tester experiment with micron-sized particles, and hence, validating this simulation remains a challenge. We address this task by down scaling the experimental setup: A fully functional micro shear-tester was developed and implemented into an X-ray tomography device in order to visualize the sample on a bulk and particle level within small bulk volumes of the order of a few micro liter under well-defined consolidation. Using spherical micron-sized particles (30 μm), shear tests with a particle number accessible for simulations can be performed. Moreover, particle level analysis allows for a direct comparison of experimental and numerical results, e.g., regarding structural evolution. In this talk, we focus on density inhomogeneity and shear induced heterogeneity during compaction and shear deformation.

  16. A Study on Reverse Logistics

    OpenAIRE

    Reddy, Dhananjaya

    2011-01-01

    In the competitive world of manufacturing, companies are often searching for new ways to improve their process, customer satisfaction and stay ahead in the game with their competitors. Reverse logistics has been considered a strategy to bring these things to life for the past decade or so. This thesis work tries to shed some light on the basics of reverse logistics and how reverse logistics can be used as a management strategy. This paper points out the fundamentals of reverse logistics and l...

  17. An injectable shear-thinning biomaterial for endovascular embolization.

    Science.gov (United States)

    Avery, Reginald K; Albadawi, Hassan; Akbari, Mohsen; Zhang, Yu Shrike; Duggan, Michael J; Sahani, Dushyant V; Olsen, Bradley D; Khademhosseini, Ali; Oklu, Rahmi

    2016-11-16

    Improved endovascular embolization of vascular conditions can generate better patient outcomes and minimize the need for repeat procedures. However, many embolic materials, such as metallic coils or liquid embolic agents, are associated with limitations and complications such as breakthrough bleeding, coil migration, coil compaction, recanalization, adhesion of the catheter to the embolic agent, or toxicity. Here, we engineered a shear-thinning biomaterial (STB), a nanocomposite hydrogel containing gelatin and silicate nanoplatelets, to function as an embolic agent for endovascular embolization procedures. STBs are injectable through clinical catheters and needles and have hemostatic activity comparable to metallic coils, the current gold standard. In addition, STBs withstand physiological pressures without fragmentation or displacement in elastomeric channels in vitro and in explant vessels ex vivo. In vitro experiments also indicated that STB embolization did not rely on intrinsic thrombosis as coils did for occlusion, suggesting that the biomaterial may be suitable for use in patients on anticoagulation therapy or those with coagulopathy. Using computed tomography imaging, the biomaterial was shown to fully occlude murine and porcine vasculature in vivo and remain at the site of injection without fragmentation or nontarget embolization. Given the advantages of rapid delivery, in vivo stability, and independent occlusion that does not rely on intrinsic thrombosis, STBs offer an alternative gel-based embolic agent with translational potential for endovascular embolization. Copyright © 2016, American Association for the Advancement of Science.

  18. Exponential Shear Flow of Linear, Entangled Polymeric Liquids

    DEFF Research Database (Denmark)

    Neergaard, Jesper; Park, Kyungho; Venerus, David C.

    2000-01-01

    A previously proposed reptation model is used to interpret exponential shear flow data taken on an entangled polystyrenesolution. Both shear and normal stress measurements are made during exponential shear using mechanical means. The model iscapable of explaining all trends seen in the data......, and suggests a novel analysis of the data. This analysis demonstrates thatexponential shearing flow is no more capable of stretching polymer chains than is inception of steady shear at comparableinstantaneous shear rates. In fact, all exponential shear flow stresses measured are bounded quantitatively...

  19. On topotaxy and compaction during antigorite and chlorite dehydration: an experimental and natural study

    Science.gov (United States)

    Padrón-Navarta, José Alberto; Tommasi, Andréa; Garrido, Carlos J.; Mainprice, David

    2015-04-01

    clinoenstatite lamellae enables estimating the local strain rates and shear stresses generated during compaction. An lower bound for the strain rates in the order of 10-12 to 10-13 s-1 and shear stresses of 60-70 MPa are estimated based on creep data. Lower shear stresses (20-40 MPa) are retrieved using a theoretical approach. These data point to slow compaction (and fluid extraction) in nature if the system is not perturbed by external forces, with rates only marginally higher than the viscoplastic deformation of the solid matrix.

  20. Numerical design and optimization of hydraulic resistance and wall shear stress inside pressure-driven microfluidic networks.

    Science.gov (United States)

    Damiri, Hazem Salim; Bardaweel, Hamzeh Khalid

    2015-11-07

    Microfluidic networks represent the milestone of microfluidic devices. Recent advancements in microfluidic technologies mandate complex designs where both hydraulic resistance and pressure drop across the microfluidic network are minimized, while wall shear stress is precisely mapped throughout the network. In this work, a combination of theoretical and modeling techniques is used to construct a microfluidic network that operates under minimum hydraulic resistance and minimum pressure drop while constraining wall shear stress throughout the network. The results show that in order to minimize the hydraulic resistance and pressure drop throughout the network while maintaining constant wall shear stress throughout the network, geometric and shape conditions related to the compactness and aspect ratio of the parent and daughter branches must be followed. Also, results suggest that while a "local" minimum hydraulic resistance can be achieved for a geometry with an arbitrary aspect ratio, a "global" minimum hydraulic resistance occurs only when the aspect ratio of that geometry is set to unity. Thus, it is concluded that square and equilateral triangular cross-sectional area microfluidic networks have the least resistance compared to all rectangular and isosceles triangular cross-sectional microfluidic networks, respectively. Precise control over wall shear stress through the bifurcations of the microfluidic network is demonstrated in this work. Three multi-generation microfluidic network designs are considered. In these three designs, wall shear stress in the microfluidic network is successfully kept constant, increased in the daughter-branch direction, or decreased in the daughter-branch direction, respectively. For the multi-generation microfluidic network with constant wall shear stress, the design guidelines presented in this work result in identical profiles of wall shear stresses not only within a single generation but also through all the generations of the

  1. Reversible brazing process

    Science.gov (United States)

    Pierce, Jim D.; Stephens, John J.; Walker, Charles A.

    1999-01-01

    A method of reversibly brazing surfaces together. An interface is affixed to each surface. The interfaces can be affixed by processes such as mechanical joining, welding, or brazing. The two interfaces are then brazed together using a brazing process that does not defeat the surface to interface joint. Interfaces of materials such as Ni-200 can be affixed to metallic surfaces by welding or by brazing with a first braze alloy. The Ni-200 interfaces can then be brazed together using a second braze alloy. The second braze alloy can be chosen so that it minimally alters the properties of the interfaces to allow multiple braze, heat and disassemble, rebraze cycles.

  2. Effect of tree roots on a shear zone: modeling reinforced shear stress.

    Science.gov (United States)

    Kazutoki Abe; Robert R. Ziemer

    1991-01-01

    Tree roots provide important soil reinforcement that impoves the stability of hillslopes. After trees are cut and roots begin to decay, the frequency of slope failures can increase. To more fully understand the mechanics of how tree roots reinforce soil, fine sandy soil containing pine roots was placed in a large shear box in horizontal layers and sheared across a...

  3. Comparison of direct shear and simple shear responses of municipal solid waste in USA

    KAUST Repository

    Fei, Xunchang

    2017-10-25

    Although large-size simple shear (SS) testing of municipal solid waste (MSW) may arguably provide a more realistic estimate of the shear strength (τ ) of MSW than the most commonly used direct shear (DS) testing, a systematic comparison between the shear responses of MSW obtained from the two testing methods is lacking. In this study, a large-size shear device was used to test identical MSW specimens sampled in USA in DS and SS. Eight DS tests and 11 SS tests were conducted at vertical effective stresses of 50–500 kPa. The stress–displacement response of MSW in SS testing was hyperbolic and a maximum shear stress was reached, whereas a maximum shear stress was not reached in most DS tests. The τ, effective friction angle (ϕ ′) and cohesion (c ′) of MSW were obtained from DS and SS tests by using a displacement failure criterion of 40 mm. τ in SS testing was found to be equal to or lower than τ in DS testing with ratios of τ between 73 and 101%. SS testing resulted in higher ϕ ′ but lower c ′ than DS testing. The shear strength parameters were lower than those obtained in previous studies from DS tests at 55 mm displacement.

  4. Reversed Pressure Compaction: A Novel Method for Processing Composite Materials Directly from Polymer Fibers

    Science.gov (United States)

    Cohen, Yachin; Rein, Dmitry M.; Vaykhansky, Lev

    2002-03-01

    “Single component” composite materials are processed directly from oriented polymer fibers without extraneous matrix. Bonding is achieved by entanglement of macromolecules that emanate from the fiber by controlled surface melting. The key element in the processing scheme is control of the fibers’ melting temperature by hydrostatic pressure, using the following steps: a) compression to high pressure (Pu) at low temperature (To), which deforms the fiber cross-section without melting. b) raising temperature to a high level (Tu), which is below the melting point of the oriented crystals at Pu. c) pPressure reduction to an intermediate level (Pm) for controlled time. At this pressure, the fibers’ begin melting from their surface and are consolidated. d) increase of pressure back to Pu stops the melting process. e) return to ambient temperature and pressure provides the finished material. This process is applicable to a wide range of polymeric materials such as ultra-high molecular weight polyethylene (UHMWPE), polypropylene, fluorinated polymers and liquid-crystalline polymers. The fact that the main processing steps occur at a constant temperature, whereby melting and crystallization are effected by control of pressure, allows enhanced homogeneity of the fabricated material. High-performance substrates for microwave antennae and circuitry have been fabricated with this manner, as will be described in the presentation.

  5. Extreme model reduction of shear layers

    Science.gov (United States)

    Qawasmeh, Bashar Rafee

    The aim of this research is to develop nonlinear low-dimensional models (LDMs) to describe vortex dynamics in shear layers. A modified Proper Orthogonal Decomposition (POD)/Galerkin projection method is developed to obtain models at extremely low dimension for shear layers. The idea is to dynamically scale the shear layer along y direction to factor out the shear layer growth and capture the dynamics by only a couple of modes. The models are developed for two flows, incompressible spatially developing and weakly compressible temporally developing shear layers, respectively. To capture basic dynamics, the low-dimensional models require only two POD modes for each wavenumber/frequency. Thus, a two-mode model is capable of representing single-wavenumber/frequency dynamics such as vortex roll-up, and a four-mode model is capable of representing the nonlinear dynamics involving a fundamental wavenumber/frequency and its subharmonic, such as vortex pairing/merging. Most of the energy is captured by the first mode of each wavenumber/frequency, the second POD mode, however, plays a critical role and needs to be included. In the thesis, we first apply the approach on temporally developing weakly compressible shear layers. In compressible flows, the thermodynamic variables are dynamically important, and must be considered. We choose isentropic Navier-Stokes equations for simplicity, and choose a proper inner product to present both kinetic energy and thermal energy. Two cases of convective Mach numbers are studied for low compressibility and moderate compressibility. Moreover, we study the sensitivity of the compressible four-mode model to several flow parameters: Mach number, the strength of initial perturbations of the fundamental and its subharmonic, and Reynolds number. Secondly we apply the approach on spatially developing incompressible shear layers with periodicity in time. We consider a streamwise parabolic form of the Navier-Stokes equations. When we add arbitrary

  6. Strategy Guideline: Compact Air Distribution Systems

    Energy Technology Data Exchange (ETDEWEB)

    Burdick, A.

    2013-06-01

    This Strategy Guideline discusses the benefits and challenges of using a compact air distribution system to handle the reduced loads and reduced air volume needed to condition the space within an energy efficient home. Traditional systems sized by 'rule of thumb' (i.e., 1 ton of cooling per 400 ft2 of floor space) that 'wash' the exterior walls with conditioned air from floor registers cannot provide appropriate air mixing and moisture removal in low-load homes. A compact air distribution system locates the HVAC equipment centrally with shorter ducts run to interior walls, and ceiling supply outlets throw the air toward the exterior walls along the ceiling plane; alternatively, high sidewall supply outlets throw the air toward the exterior walls. Potential drawbacks include resistance from installing contractors or code officials who are unfamiliar with compact air distribution systems, as well as a lack of availability of low-cost high sidewall or ceiling supply outlets to meet the low air volumes with good throw characteristics. The decision criteria for a compact air distribution system must be determined early in the whole-house design process, considering both supply and return air design. However, careful installation of a compact air distribution system can result in lower material costs from smaller equipment, shorter duct runs, and fewer outlets; increased installation efficiencies, including ease of fitting the system into conditioned space; lower loads on a better balanced HVAC system, and overall improved energy efficiency of the home.

  7. Pulsatility Index as a Diagnostic Parameter of Reciprocating Wall Shear Stress Parameters in Physiological Pulsating Waveforms.

    Directory of Open Access Journals (Sweden)

    Idit Avrahami

    Full Text Available Arterial wall shear stress (WSS parameters are widely used for prediction of the initiation and development of atherosclerosis and arterial pathologies. Traditional clinical evaluation of arterial condition relies on correlations of WSS parameters with average flow rate (Q and heart rate (HR measurements. We show that for pulsating flow waveforms in a straight tube with flow reversals that lead to significant reciprocating WSS, the measurements of HR and Q are not sufficient for prediction of WSS parameters. Therefore, we suggest adding a third quantity-known as the pulsatility index (PI-which is defined as the peak-to-peak flow rate amplitude normalized by Q. We examine several pulsating flow waveforms with and without flow reversals using a simulation of a Womersley model in a straight rigid tube and validate the simulations through experimental study using particle image velocimetry (PIV. The results indicate that clinically relevant WSS parameters such as the percentage of negative WSS (P[%], oscillating shear index (OSI and the ratio of minimum to maximum shear stress rates (min/max, are better predicted when the PI is used in conjunction with HR and Q. Therefore, we propose to use PI as an additional and essential diagnostic quantity for improved predictability of the reciprocating WSS.

  8. Phased array compaction cell for measurement of the transversely isotropic elastic properties of compacting sediments

    Energy Technology Data Exchange (ETDEWEB)

    Nihei, K.T.; Nakagawa, S.; Reverdy, F.; Meyer, L.R.; Duranti, L.; Ball, G.

    2010-12-15

    Sediments undergoing compaction typically exhibit transversely isotropic (TI) elastic properties. We present a new experimental apparatus, the phased array compaction cell, for measuring the TI elastic properties of clay-rich sediments during compaction. This apparatus uses matched sets of P- and S-wave ultrasonic transducers located along the sides of the sample and an ultrasonic P-wave phased array source, together with a miniature P-wave receiver on the top and bottom ends of the sample. The phased array measurements are used to form plane P-waves that provide estimates of the phase velocities over a range of angles. From these measurements, the five TI elastic constants can be recovered as the sediment is compacted, without the need for sample unloading, recoring, or reorienting. This paper provides descriptions of the apparatus, the data processing, and an application demonstrating recovery of the evolving TI properties of a compacting marine sediment sample.

  9. Stochastic parametric resonance in shear flows

    Directory of Open Access Journals (Sweden)

    F. J. Poulin

    2005-01-01

    Full Text Available Time-periodic shear flows can give rise to Parametric Instability (PI, as in the case of the Mathieu equation (Stoker, 1950; Nayfeh and Mook, 1995. This mechanism results from a resonance between the oscillatory basic state and waves that are superimposed on it. Farrell and Ioannou (1996a, b explain that PI occurs because the snap-shots of the velocity profile are subject to transient growth. If the flows were purely steady the transient growth would subside and not have any long lasting effect. However, the coupling between transient growth and the time variation of the basic state create PI. Mathematically, transient growth, and therefore PI, are due to the nonorthogonal eigenspace in the linearized system. Poulin et al. (2003 studied a time-periodic barotropic shear flow that exhibited PI, and thereby produced mixing at the interface between Potential Vorticity (PV fronts. The instability led to the formation of vortices that were stretched. A later study of an oscillatory current in the Cape Cod Bay illustrated that PI can occur in realistic shear flows (Poulin and Flierl, 2005. These studies assumed that the basic state was periodic with a constant frequency and amplitude. In this work we study a shear flow similar to that found in Poulin et al. (2003, but now where the magnitude of vorticity is a stochastic variable. We determine that in the case of stochastic shear flows the transient growth of perturbations of the snapshots of the basic state still generate PI.

  10. Piezoelectric energy harvesting through shear mode operation

    International Nuclear Information System (INIS)

    Malakooti, Mohammad H; Sodano, Henry A

    2015-01-01

    Piezoelectric materials are excellent candidates for use in energy harvesting applications due to their high electromechanical coupling properties that enable them to convert input mechanical energy into useful electric power. The electromechanical coupling coefficient of the piezoelectric material is one of the most significant parameters affecting energy conversion and is dependent on the piezoelectric mode of operation. In most piezoceramics, the d 15 piezoelectric shear coefficient is the highest coefficient compared to the commonly used axial and transverse modes that utilize the d 33 and the d 31 piezoelectric strain coefficients. However, complicated electroding methods and challenges in evaluating the performance of energy harvesting devices operating in the shear mode have slowed research in this area. The shear deformation of a piezoelectric layer can be induced in a vibrating sandwich beam with a piezoelectric core. Here, a model based on Timoshenko beam theory is developed to predict the electric power output from a cantilever piezoelectric sandwich beam under base excitations. It is shown that the energy harvester operating in the shear mode is able to generate ∼50% more power compared to the transverse mode for a numerical case study. Reduced models of both shear and transverse energy harvesters are obtained to determine the optimal load resistance in the system and perform an efficiency comparison between two models with fixed and adaptive resistances. (paper)

  11. Examining shear processes during magma ascent

    Science.gov (United States)

    Kendrick, J. E.; Wallace, P. A.; Coats, R.; Lamur, A.; Lavallée, Y.

    2017-12-01

    Lava dome eruptions are prone to rapid shifts from effusive to explosive behaviour which reflects the rheology of magma. Magma rheology is governed by composition, porosity and crystal content, which during ascent evolves to yield a rock-like, viscous suspension in the upper conduit. Geophysical monitoring, laboratory experiments and detailed field studies offer the opportunity to explore the complexities associated with the ascent and eruption of such magmas, which rest at a pivotal position with regard to the glass transition, allowing them to either flow or fracture. Crystal interaction during flow results in strain-partitioning and shear-thinning behaviour of the suspension. In a conduit, such characteristics favour the formation of localised shear zones as strain is concentrated along conduit margins, where magma can rupture and heal in repetitive cycles. Sheared magmas often record a history of deformation in the form of: grain size reduction; anisotropic permeable fluid pathways; mineral reactions; injection features; recrystallisation; and magnetic anomalies, providing a signature of the repetitive earthquakes often observed during lava dome eruptions. The repetitive fracture of magma at ( fixed) depth in the conduit and the fault-like products exhumed at spine surfaces indicate that the last hundreds of meters of ascent may be controlled by frictional slip. Experiments on a low-to-high velocity rotary shear apparatus indicate that shear stress on a slip plane is highly velocity dependent, and here we examine how this influences magma ascent and its characteristic geophysical signals.

  12. Evaluation of shear mounted elastomeric damper

    Science.gov (United States)

    Zorzi, E.; Walton, J.

    1982-01-01

    Viton-70 elastomeric shear mounted damper was built and tested on a T-55 power turbine spool in the rotor's high speed balancing rig. This application of a shear mounted elastomeric damper demonstrated for the first time, the feasibility of using elastomers as the primary rotor damping source in production turbine engine hardware. The shear damper design was selected because it was compatible with actual gas turbine engine radial space constraints, could accommodate both the radial and axial thrust loads present in gas turbine engines, and was capable of controlled axial preload. The shear damper was interchangeable with the production T-55 power turbine roller bearing support so that a direct comparison between the shear damper and the production support structure could be made. Test results show that the Viton-70 elastomer damper operated successfully and provided excellent control of both synchronous and nonsynchronous vibrations through all phases of testing up to the maximum rotor speed of 16,000 rpm. Excellent correlation between the predicted and experienced critical speeds, mode shapes and log decrements for the power turbine rotor and elastomer damper assembly was also achieved.

  13. Electrostatic ion cyclotron velocity shear instability

    International Nuclear Information System (INIS)

    Lemons, D.S.; Winske, D.; Gary, S.P.

    1992-01-01

    An electrostatic ion cyclotron instability driven by sheared velocity flow perpendicular to a uniform magnetic field is investigated in the local approximation. The dispersion equation, which includes all kinetic effects and involves only one important parameter, is cast in the form of Gordeyev integrals and solved numerically. The instability occurs roughly at multiples of the ion cyclotron frequency (but modified by the shear) with the growth rate of the individual harmonics overlapping in wavenumber. At small values of the shear parameter, the instability exists in two branches, one at long wavelength, κρ i ∼ 0.5, and one at short wavelength, κρ i > 1.5 (κρ i is the wavenumber normalized to the ion gyroradius). At larger values of the shear parameter only the longer wavelength branch persists. The growth rate of the long wavelength mode, maximized over wavenumber and frequency, increases monotonically with the shear parameter. Properties of the instability are compared to those of Ganguli et al. obtained in the nonlocal limit

  14. Colloidal Aggregate Structure under Shear by USANS

    Science.gov (United States)

    Chatterjee, Tirtha; van Dyk, Antony K.; Ginzburg, Valeriy V.; Nakatani, Alan I.

    2015-03-01

    Paints are complex formulations of polymeric binders, inorganic pigments, dispersants, surfactants, colorants, rheology modifiers, and other additives. A commercially successful paint exhibits a desired viscosity profile over a wide shear rate range from 10-5 s-1 for settling to >104 s-1 for rolling, and spray applications. Understanding paint formulation structure is critical as it governs the paint viscosity profile. However, probing paint formulation structure under shear is a challenging task due to the formulation complexity containing structures with different hierarchical length scales and their alterations under the influence of an external flow field. In this work mesoscale structures of paint formulations under shear are investigated using Ultra Small-Angle Neutron Scattering (rheo-USANS). Contrast match conditions were utilized to independently probe the structure of latex binder particle aggregates and the TiO2 pigment particle aggregates. Rheo-USANS data revealed that the aggregates are fractal in nature and their self-similarity dimensions and correlations lengths depend on the chemistry of the binder particles, the type of rheology modifier present and the shear stress imposed upon the formulation. These results can be explained in the framework of diffusion and reaction limited transient aggregates structure evolution under simple shear.

  15. Pressure-shear experiments on granular materials.

    Energy Technology Data Exchange (ETDEWEB)

    Reinhart, William Dodd (Sandia National Laboratories, Albuquerque, NM); Thornhill, Tom Finley, III (, Sandia National Laboratories, Albuquerque, NM); Vogler, Tracy John; Alexander, C. Scott (Sandia National Laboratories, Albuquerque, NM)

    2011-10-01

    Pressure-shear experiments were performed on granular tungsten carbide and sand using a newly-refurbished slotted barrel gun. The sample is a thin layer of the granular material sandwiched between driver and anvil plates that remain elastic. Because of the obliquity, impact generates both a longitudinal wave, which compresses the sample, and a shear wave that probes the strength of the sample. Laser velocity interferometry is employed to measure the velocity history of the free surface of the anvil. Since the driver and anvil remain elastic, analysis of the results is, in principal, straightforward. Experiments were performed at pressures up to nearly 2 GPa using titanium plates and at higher pressure using zirconium plates. Those done with the titanium plates produced values of shear stress of 0.1-0.2 GPa, with the value increasing with pressure. On the other hand, those experiments conducted with zirconia anvils display results that may be related to slipping at an interface and shear stresses mostly at 0.1 GPa or less. Recovered samples display much greater particle fracture than is observed in planar loading, suggesting that shearing is a very effective mechanism for comminution of the grains.

  16. Experimental studies of compaction and dilatancy during frictional sliding on faults containing gouge

    Science.gov (United States)

    Morrow, C.A.; Byerlee, J.D.

    1989-01-01

    Transient strength changes are observed in fault gouge materials when the velocity of shearing is varied. A transient stress peak is produced when the strain rate in the gouge is suddenly increased, whereas a transient stress drop results from a sudden change to a slower strain rate. We have studied the mechanism responsible for these observations by performing frictional sliding experiments on sawcut granite samples filled with a layer of several different fault gouge types. Changes in pore volume and strength were monitored as the sliding velocity alternated between fast and slow rates. Pore volume increased at the faster strain rate, indicating a dilation of the gouge layer, whereas volume decreased at the slower rate indicating compaction. These results verify that gouge dilation is a function of strain rate. Pore volume changed until an equilibrium void ratio of the granular material was reached for a particular rate of strain. Using arguments from soil mechanics, we find that the dense gouge was initially overconsolidated relative to the equilibrium level, whereas the loose gouge was initially underconsolidated relative to this level. Therefore, the transient stress behavior must be due to the overconsolidated state of the gouge at the new rate when the velocity is increased and to the underconsolidated state when the velocity is lowered. Time-dependent compaction was also shown to cause a transient stress response similar to the velocity-dependent behavior. This may be important in natural fault gouges as they become consolidated and stronger with time. In addition, the strain hardening of the gouge during shearing was found to be a function of velocity, rendering it difficult to quantify the change in equilibrium shear stress when velocity is varied under certain conditions. ?? 1989.

  17. Long time scale plasma dynamics driven by the double tearing mode in reversed shear plasmas

    International Nuclear Information System (INIS)

    Ishii, Y.; Azumi, M.; Kishimoto, Y.; Leboeuf, J.N.

    2003-01-01

    The new nonlinear destabilization process is found in the nonlinear phase of the double tearing mode (DTM) by using the reduced MHD equations in a helical symmetry. The nonlinear destabilization causes the abrupt growth of DTM and subsequent collapse after long time scale evolution in the Rutherford-type regime. The nonlinear growth of the DTM is suddenly triggered, when the triangular deformation of magnetic islands with sharp current point at the x-point around the outer rational surface exceeds a certain value. Such structure deformation is accelerated during the nonlinear growth phase. Decreasing the resistivity increases the sharpness of the triangularity and the spontaneous growth rate in the abrupt growth phase is almost independent on the resistivity. Current point formation is also confirmed in the multi-helicity simulation, where the magnetic fields become stochastic between two rational surfaces. (author)

  18. Core density fluctuations in reverse magnetic shear plasmas with internal transport barrier on JT-60U

    International Nuclear Information System (INIS)

    Nazikian, R.; Shinohara, K.; Yoshino, R.; Fujita, T.; Shirai, H.; Kramer, G.T.

    1999-01-01

    First measurements of the radial correlation length of density fluctuations in JT-60U plasmas with internal transport barrier (ITB) is reported. The measurements are obtained using a newly installed correlation reflectometer operating in the upper X-mode. Before transport barrier formation in the low beam power current ramp-up phase of the discharge, reflectometer measurements indicate density fluctuation levels n-tilde/n∼0.1-0.2% and radial correlation lengths 2-3 cm (k r p i ≤0.5) in the central plasma region (r/a r p i ∼3. However, fluctuation levels are considerably higher than measured near the magnetic axis. Reflectometer measurements obtained at the foot of the ITB also indicate high fluctuation levels compared to measurements in the central region of the discharge. (author)

  19. Core density fluctuations in reverse magnetic shear plasmas with internal transport barrier on JT-60U

    International Nuclear Information System (INIS)

    Nazikian, R.; Shinohara, K.; Yoshino, R.; Fujita, T.; Shirai, H.; Kramer, G.J.

    2001-01-01

    First measurements of the radial correlation length of density fluctuations in JT-60U plasmas with internal transport barrier (ITB) is reported. The measurements are obtained using a newly installed correlation reflectometer operating in the upper X-mode. Before transport barrier formation in the low beam power current ramp-up phase of the discharge, reflectometer measurements indicate density fluctuation levels n-tilde/n ∼ 0.1 - 0.2% and radial correlation lengths 2-3 cm (k r ρ i ≤ 0.5) in the central plasma region ( r/a r ρ i ∼ 3. However, fluctuation levels are considerably higher than measured near the magnetic axis. Reflectometer measurements obtained at the foot of the ITB also indicate high fluctuation levels compared to measurements in the central region of the discharge. (author)

  20. Compaction of Ti–6Al–4V powder using high velocity compaction technique

    International Nuclear Information System (INIS)

    Khan, Dil Faraz; Yin, Haiqing; Li, He; Qu, Xuanhui; Khan, Matiullah; Ali, Shujaat; Iqbal, M. Zubair

    2013-01-01

    Highlights: • We compacted Ti–6Al–4V powder by HVC technique. • As impact force rises up, the green density of the compacts increases gradually. • At impact force 1.857 kN relative sintered density of the compacts reaches 99.88%. • Spring back of the green compact’s decreases gradually with increasing impact force. • Mechanical properties of the samples increases with increasing impact force. - Abstract: High velocity compaction technique was applied to the compaction of pre-alloyed, hydride–dehydride Ti–6Al–4V powder. The powder was pressed in single stroke with a compaction speed of 7.10–8.70 ms −1 . When the speed was 8.70 ms −1 , the relative density of the compacts reaches up to 85.89% with a green density of 3.831 g cm −3 . The green samples were sintered at 1300 °C in Ar-gas atmosphere. Scanning electron microscope (SEM) was used to examine the surface of the sintered samples. Density and mechanical properties such as Vickers micro hardness and bending strength of the powder samples were investigated. Experimental results indicated that with the increase in impact force, the density and mechanical properties of the compacts increased. The sintered compacts exhibited a maximum relative density of 99.88% with a sintered density of 4.415 g cm −3 , hardness of 364–483 HV and the bending strength in the range of 103–126.78 MPa. The springback of the compacts decreased with increasing impact force

  1. Reversibly Bistable Flexible Electronics

    KAUST Repository

    Alfaraj, Nasir

    2015-05-01

    Introducing the notion of transformational silicon electronics has paved the way for integrating various applications with silicon-based, modern, high-performance electronic circuits that are mechanically flexible and optically semitransparent. While maintaining large-scale production and prototyping rapidity, this flexible and translucent scheme demonstrates the potential to transform conventionally stiff electronic devices into thin and foldable ones without compromising long-term performance and reliability. In this work, we report on the fabrication and characterization of reversibly bistable flexible electronic switches that utilize flexible n-channel metal-oxide-semiconductor field-effect transistors. The transistors are fabricated initially on rigid (100) silicon substrates before they are peeled off. They can be used to control flexible batches of light-emitting diodes, demonstrating both the relative ease of scaling at minimum cost and maximum reliability and the feasibility of integration. The peeled-off silicon fabric is about 25 µm thick. The fabricated devices are transferred to a reversibly bistable flexible platform through which, for example, a flexible smartphone can be wrapped around a user’s wrist and can also be set back to its original mechanical position. Buckling and cyclic bending of such host platforms brings a completely new dimension to the development of flexible electronics, especially rollable displays.

  2. The effect of mechanical dry coating with magnesium stearate on flowability and compactibility of plastically deforming microcrystalline cellulose powders.

    Science.gov (United States)

    Koskela, Jaana; Morton, David A V; Stewart, Peter J; Juppo, Anne M; Lakio, Satu

    2018-02-15

    Mechanofusion is a dry coating method that can be used to improve the flowability of cohesive powder by coating host particles with a lubricant, for example magnesium stearate (MgSt). It has been shown previously that fragmenting material can under some circumstances be mechanofused with MgSt without impairing compactibility of the powder and without reducing the dissolution rate of the resulting tablets. However, the effects on material with viscoelastic behaviour, known to be sensitive for the negative effects of MgSt, is not known. Therefore, mechanofusion of microcrystalline cellulose (MCC) with MgSt was investigated in this study. Four MCC grades were mechanofused with different MgSt concentrations and process parameters, and the resulting flowability and compactibility were studied. Starting materials and low-shear blended binary mixtures were studied as a reference. Mechanofusion improved the flow properties of small particle size MCC powders (d50 < 78 μm) substantially, but increasing the MgSt content consequently resulted in weaker tablets. Larger particle size MCC grades, however, fractured under the shear forces during the mechanofusion process and hence their flow properties were decreased. Improvement of the flow properties but also the negative effects on compactibility of small particle size grades were observed even at relatively mild mechanofusion parameters and low lubricant concentrations. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Hydrodynamic interactions between two equally sized spheres in viscoelastic fluids in shear flow.

    Science.gov (United States)

    Snijkers, Frank; Pasquino, Rossana; Vermant, Jan

    2013-05-14

    The effect of using a viscoelastic suspending medium on the in-plane hydrodynamic interaction between two equally sized spheres in shear flow is studied experimentally to understand flow-induced assembly behavior (i.e., string formation). A counterrotating device equipped with a Couette geometry is used together with quantitative videomicroscopy. To evaluate the effects of differences in rheological properties of the suspending media, fluids have been selected that highlight specific constitutive features. These include a reference Newtonian fluid (N), a constant-viscosity, high-elasticity Boger fluid (BF), a wormlike micellar surfactant solution with a single dominant relaxation time (WMS), and a broad spectrum shear-thinning elastic polymer solution (ST). As expected, the trajectories are symmetric in the Newtonian fluid. In the BF, the midpoints of the spheres are observed to remain in the same plane before and after the interaction, as in the Newtonian fluid, although the path lines are in this case no longer symmetric. Interactions in the ST and WMS are highly asymmetric. Two fundamentally different kinds of path lines are observed in the WMS and ST: reversing and open trajectories. The type of trajectory depends on the initial configuration of the spheres with respect to each other and on the shear rate. On the basis of the obtained results, shear-thinning of the viscosity seems to be the key rheological parameter that determines the overall nature of the interactions, rather than the relative magnitude of the normal stress differences.

  4. Radiation shielding aspects of compact medical cyclotrons

    International Nuclear Information System (INIS)

    Mukherjee, B.; Ruth, T.J.

    1995-01-01

    Hospital-based compact medical cyclotrons are commonly used to produce large activities of short-lived PET radioisotopes such as fluorine-18 (HL110 min) and oxygen-18 (HL= 20 min), by bombarding suitably enriched gas or liquid targets with 11-15 MeV protons. High energy prompt neutron/gamma radiation fields are generated as the nuclear reaction product. The compact medical cyclotrons are installed either inside or in the close proximity of the nuclear medicine clinic. Therefore the adequacy of the radiation shielding is vitally important for the radiological safety of the patients and members of the public. The present paper highlights the important radiation shielding aspects of some compact medical cyclotrons presently available in the international market. 2 tabs., 4 figs

  5. Compaction and sedimentary basin analysis on Mars

    Science.gov (United States)

    Gabasova, Leila R.; Kite, Edwin S.

    2018-03-01

    Many of the sedimentary basins of Mars show patterns of faults and off-horizontal layers that, if correctly understood, could serve as a key to basin history. Sediment compaction is a possible cause of these patterns. We quantified the possible role of differential sediment compaction for two Martian sedimentary basins: the sediment fill of Gunjur crater (which shows concentric graben), and the sediment fill of Gale crater (which shows outward-dipping layers). We assume that basement topography for these craters is similar to the present-day topography of complex craters that lack sediment infill. For Gunjur, we find that differential compaction produces maximum strains consistent with the locations of observed graben. For Gale, we were able to approximately reproduce the observed layer orientations measured from orbiter image-based digital terrain models, but only with a >3 km-thick donut-shaped past overburden. It is not immediately obvious what geologic processes could produce this shape.

  6. Activation analysis of the compact ignition tokamak

    International Nuclear Information System (INIS)

    Selcow, E.C.

    1986-01-01

    The US fusion program has completed the conceptual design of a compact tokamak device that achieves ignition. The high neutron wall loadings associated with this compact deuterium-tritium-burning device indicate that radiation-related issues may be significant considerations in the overall system design. Sufficient shielding will be requied for the radiation protection of both reactor components and occupational personnel. A close-in igloo shield has been designed around the periphery of the tokamak structure to permit personnel access into the test cell after shutdown and limit the total activation of the test cell components. This paper describes the conceptual design of the igloo shield system and discusses the major neutronic concerns related to the design of the Compact Ignition Tokamak

  7. JAPC Compact Simulator evolution to latest integration

    International Nuclear Information System (INIS)

    Nabeta, T.; Nakayama, Y.

    1999-01-01

    This paper describes the evolution of JAPC compact simulator from the first installation in 1988 until recent integration with SIMULATE-3 engineering code core model and extended simulation for Mid-loop operation and severe accidents. JAPC Compact Simulator has an advanced super compact rotating panel design. Three plants, Tokai 2 (GE BWR 5), Tsuruga 1 (GE BWR 2), Tsuruga 2 (MHI PWR 4-Loop) are simulated. The simulator has been used for training of operator and engineering personnel, and has continuously been upgraded to follow normal plant modifications as well as development in modeling and computer technology. The integration of SIMULATE-3 core model is, to our knowledge, the first integration of a real design code into a training simulator. SIMULATE-3 has been successfully integrated into the simulator and run in real time, without compromising the accuracy of SIMULATE-3. The code has been modified to also handle mid-loop operation and severe accidents. (author)

  8. Coherent states for quantum compact groups

    CERN Document Server

    Jurco, B

    1996-01-01

    Coherent states are introduced and their properties are discussed for all simple quantum compact groups. The multiplicative form of the canonical element for the quantum double is used to introduce the holomorphic coordinates on a general quantum dressing orbit and interpret the coherent state as a holomorphic function on this orbit with values in the carrier Hilbert space of an irreducible representation of the corresponding quantized enveloping algebra. Using Gauss decomposition, the commutation relations for the holomorphic coordinates on the dressing orbit are derived explicitly and given in a compact R--matrix formulation (generalizing this way the q--deformed Grassmann and flag manifolds). The antiholomorphic realization of the irreducible representations of a compact quantum group (the analogue of the Borel--Weil construction) are described using the concept of coherent state. The relation between representation theory and non--commutative differential geometry is suggested.}

  9. Challenges: a state and compact perspective

    International Nuclear Information System (INIS)

    Brown, H.

    1987-01-01

    The challenges facing states and compacts in their efforts to implement the Low-Level Waste Policy Amendments Act are described. Institutional challenges include: small-volume sites; compact maintenance; shifting agencies and changing personnel; and timing of progress. The technical challenge lies in the enormous number of plans, procedures, and regulations that have to be developed over the next four years. There are two main fiscal challenges: funding of day-to-day operations of compact commissions; and financing the siting and construction of new disposal sites. There are also two main regulatory challenges: host states must develop regulations for siting and selection of technology; and all states have to await federal regulations to be completed. The final challenge is political: whether a region can overcome public opposition and actually site a facility

  10. The effect of particle shape on mixing in a high shear mixer

    Science.gov (United States)

    Sinnott, Matthew D.; Cleary, Paul W.

    2016-11-01

    Discrete element method modelling is used to study the effect of particle shape on the flow dynamics and mixing in a high shear mixer. The blade generates strong flow over its top surface while compacting and pushing forward particles that are directly in front of the blade. A complex three dimensional flow is established with vertical and radial flow components that are shape dependent and which control the nature of the mixing. Mixing was found to be fast in the azimuthal direction, of intermediate speed in the vertical direction and comparatively slow in the radial mixing. Diffusive mixing is characterised using the granular temperature which shows that the regions of higher granular temperature are larger for round particles than non-round ones leading to stronger diffusive mixing. The spatial distribution of the convective component of mixing is identified using novel calculation of shear strain rate. This size and shape of the high shear region is found to be only slightly sensitive to the particle shape indicating that the convective mixing is relatively independent of shape, except in the middle of the mixer. The blockiness of the particles has the strongest impact on flow and mixing while the mixing has only a weak dependence on the particle aspect ratio.

  11. Sand production prediction using ratio of shear modulus to bulk compressibility (case study

    Directory of Open Access Journals (Sweden)

    Ehsan Khamehchi

    2015-06-01

    Full Text Available Sand production is a serious problem widely existing in oil/gas production. The problems resulting from sand influx include abrasion of downhole tubular/casing, subsurface safety valve and surface equipment; casing/tubing buckling, failure of casing or liners from removal of surrounding formation, compaction and erosion; and loss of production caused by sand bridging in tubing and/or flow lines. There are several methods for predicting sand production. The methods include use of production data, well logs, laboratory testing, acoustic, intrusive sand monitoring devices, and analogy. The methodologies are reviewed and the data needed for predicting sand production are enumerated. The technique used in this paper involves the calculation of shear modulus, bulk compressibility, and the ratio of shear modulus to bulk compressibility. The shear modulus to bulk compressibility ratio has been related empirically to sand influx. This Mechanical Properties Log method works 81% of the time. This technique is supported with examples and case studies from regions around the world known for sand production. The authors collected the information of the “Kaki and Bushgan Oilfield in Iran”, set a sand production prediction to predict sand production potential. The technique has been successfully applied in reservoirs and results have been compared with testing data.

  12. Transversely Compressed- and Restrained Shear Joints

    DEFF Research Database (Denmark)

    Schmidt, Jacob Wittrup; Hansen, Christian Skodborg

    2013-01-01

    Anchorage of FRP strengthening systems where the deformation perpendicular to the FRP material is restrained or a compressive force is applied on the strengthening, seems to provide ductility, increased utilization of the FRP and failure modes which can be controlled through the anchorage method....... This paper presents theoretical model which can predict the response of transversely compressed and restrained single- and double lap shear joints. The interface material model is based on a cohesive law in the shear-slip plane with a descending branch and a uniform frictional stress added due...... to the friction in the crack, emanating from the transverse pressure or restraint. The theoretical model is compared with experimental results from transversely compressed single- and double shear joints. Also theoretical predictions of a mechanical integrated sleeve-wedge anchorage load capacity are carried out...

  13. On shear rheology of gel propellants

    Energy Technology Data Exchange (ETDEWEB)

    Rahimi, Shai; Peretz, Arie [RAFAEL, MANOR Propulsion and Explosive Systems Division, Haifa (Israel); Natan, Benveniste [Faculty of Aerospace Engineering, Technion - Israel Institute of Technology, Haifa (Israel)

    2007-04-15

    Selected fuel, oxidizer and simulant gels were prepared and rheologically characterized using a rotational rheometer. For fuel gelation both organic and inorganic gellants were utilized, whereas oxidizers and simulants were gelled with addition of silica and polysaccharides, respectively. The generalized Herschel-Bulkley constitutive model was found to most adequately represent the gels studied. Hydrazine-based fuels, gelled with polysaccharides, were characterized as shear-thinning pseudoplastic fluids with low shear yield stress, whereas inhibited red-fuming nitric acid (IRFNA) and hydrogen peroxide oxidizers, gelled with silica, were characterized as yield thixotropic fluids with significant shear yield stress. Creep tests were conducted on two rheological types of gels with different gellant content and the results were fitted by Burgers-Kelvin viscoelastic constitutive model. The effect of temperature on the rheological properties of gel propellant simulants was also investigated. A general rheological classification of gel propellants and simulants is proposed. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  14. Observational properties of compact groups of galaxies

    International Nuclear Information System (INIS)

    Hickson, P.

    1990-01-01

    Compact groups are small, relatively isolated, systems of galaxies with projected separations comparable to the diameters of the galaxies themselves. Two well-known examples are Stephan's Quintet (Stephan, 1877) and Seyfert's Sextet (Seyfert 1948a,b). In groups such as these, the apparent space density of galaxies approaches 10(exp 6) Mpc(sub -3), denser even than the cores of rich clusters. The apparent unlikeliness of the chance occurrence of such tight groupings lead Ambartsumyan (1958, 1975) to conclude that compact groups must be physically dense systems. This view is supported by clear signs of galaxy interactions that are seen in many groups. Spectroscopic observations reveal that typical relative velocities of galaxies in the groups are comparable to their internal stellar velocities. This should be conducive to strong gravitational interactions - more so than in rich clusters, where galaxy velocities are typically much higher. This suggests that compact groups could be excellent laboratories in which to study galaxy interactions and their effects. Compact groups often contain one or more galaxies whose redshift differs greatly from those of the other group members. If these galaxies are at the same distance as the other members, either entire galaxies are being ejected at high velocities from these groups, or some new physical phenomena must be occurring. If their redshifts are cosmological, we must explain why so many discordant galaxies are found in compact groups. In recent years much progress has been made in addressing these questions. Here, the author discusses the current observational data on compact groups and their implications

  15. Measured temperature and pressure dependence of Vp and Vs in compacted, polycrystalline sI methane and sII methane-ethane hydrate

    Science.gov (United States)

    Helgerud, M.B.; Waite, W.F.; Kirby, S.H.; Nur, A.

    2003-01-01

    We report on compressional- and shear-wave-speed measurements made on compacted polycrystalline sI methane and sII methane-ethane hydrate. The gas hydrate samples are synthesized directly in the measurement apparatus by warming granulated ice to 17??C in the presence of a clathrate-forming gas at high pressure (methane for sI, 90.2% methane, 9.8% ethane for sII). Porosity is eliminated after hydrate synthesis by compacting the sample in the synthesis pressure vessel between a hydraulic ram and a fixed end-plug, both containing shear-wave transducers. Wave-speed measurements are made between -20 and 15??C and 0 to 105 MPa applied piston pressure.

  16. Spherical conformal models for compact stars

    Energy Technology Data Exchange (ETDEWEB)

    Takisa, P.M.; Maharaj, S.D.; Manjonjo, A.M.; Moopanar, S. [University of KwaZulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, Durban (South Africa)

    2017-10-15

    We consider spherical exact models for compact stars with anisotropic pressures and a conformal symmetry. The conformal symmetry condition generates an integral relationship between the gravitational potentials. We solve this condition to find a new anisotropic solution to the Einstein field equations. We demonstrate that the exact solution produces a relativistic model of a compact star. The model generates stellar radii and masses consistent with PSR J1614-2230, Vela X1, PSR J1903+327 and Cen X-3. A detailed physical examination shows that the model is regular, well behaved and stable. The mass-radius limit and the surface red shift are consistent with observational constraints. (orig.)

  17. Magnetohydrodynamic effects of current profile control in reversed field pinches

    International Nuclear Information System (INIS)

    Sovinec, C.R.; Prager, S.C.

    1999-01-01

    Linear and non-linear MHD computations are used to investigate reversed field pinch configurations with magnetic fluctuations reduced through current profile control. Simulations with reduced ohmic drive and moderate auxiliary current drive, represented generically with an electron force term, applied locally in radius near the plasma edge show magnetic fluctuation energies that are orders of magnitude smaller than those in simulations without profile control. The core of the improved configurations has reduced magnetic shear and closed flux surfaces in some cases, and reversal is sustained through the auxiliary current drive. Modes resonant near the edge may become unstable with auxiliary drive, but their saturation levels can be controlled. The space of auxiliary drive parameters is explored, and the ill effects of deviating far from optimal conditions is demonstrated in non-linear simulations. (author)

  18. Mechanical properties of self-compacting concrete state-of-the-art report of the RILEM technical committee 228-MPS on mechanical properties of self-compacting concrete

    CERN Document Server

    Schutter, Geert

    2014-01-01

    The State-of-the-Art Report of RILEM Technical Committee 228-MPS on Mechanical properties of Self-Compacting Concrete (SCC) summarizes an extensive body of information related to mechanical properties and mechanical behaviour of SCC. Due attention is given to the fact that the composition of SCC varies significantly. A wide range of  mechanical properties are considered, including compressive strength, stress-strain relationship, tensile and flexural strengths, modulus of elasticity, shear strength, effect of elevated temperature, such as fire spalling and residual properties after fire, in-situ properties, creep, shrinkage, bond properties, and structural behaviour. A chapter on fibre-reinforced SCC is included, as well as a chapter on specialty SCC, such as light-weight SCC, heavy-weight SCC, preplaced aggregate SCC, special fibre reinforced SCC, and underwater concrete.

  19. Reversible posterior leukoencephalopathy syndrome

    International Nuclear Information System (INIS)

    Lee, Eun Ja; Yu, Won Jong; Ahn, Kook Jin; Jung, So Lyung; Lee, Yeon Soo; Kim, Ji Chang; Kang, Si Won; Song, Chang Joon; Song, Soon-Young; Koo, Ja Hong; Kim, Man Deuk

    2001-01-01

    To review reversible posterior leukoencephalopathy syndrome. We reviewed 22 patients (M:F=3:19; age, 17-46 years) with the characteristic clinical and imaging features of reversible posterior leukoencephalopathy syndrome. All underwent brain MRI, and in three cases both CT and MRI were performed. In one, MRA was obtained, and in eleven, follow-up MR images were obtained. We evaluated the causes of this syndrome, its clinical manifestations, and MR findings including the locations of lesions, the presence or absence of contrast enhancement, and the changes seen at follow-up MRI. Of the 22 patients, 13 had eclampsia (six during pregnancy and seven during puerperium). Four were receiving immunosuppressive therapy (three, cyclosporine ; one, FK 506). Four suffered renal failure and one had complicated migraine. The clinical manifestations included headache (n=12), visual disturbance (n=13), seizure (n=15), focal neurologic sign (n=3), and altered mental status (n=2). Fifteen patients had hypertension and the others normotension. MRI revealed that lesions were bilateral (n=20) or unilateral (n=2). In all patients the lesion was found in the cortical and subcortical areas of the parieto-occipital lobes ; other locations were the basal ganglia (n=9), posterior temporal lobe (n=8), frontal lobe (n=5), cerebellum (n=5), pons (n=2), and thalamus (n=1). All lesions were of high signal intensity on T2-weighted images, and of iso to low intensity on T1-weighted images. One was combined with acute hematoma in the left basal ganglia. In eight of 11 patients who underwent postcontrast T1-weighted MRI, there was no definite enhancement ; in one, enhancement was mild, and in tow, patchy. CT studies showed low attenuation, and MRA revealed mild vasospasm. The symptoms of all patients improved. Follow-up MRI in nine of 11 patients depicted complete resolution of the lesions ; in two, small infarctions remained but the extent of the lesions had decreased. Reversible posterior

  20. Reversible posterior leukoencephalopathy syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Ja; Yu, Won Jong; Ahn, Kook Jin; Jung, So Lyung; Lee, Yeon Soo; Kim, Ji Chang; Kang, Si Won [The Catholic Univ. of Korea, Taejon (Korea, Republic of); Song, Chang Joon [Chungnam National Univ. School of Medicine, Cheonju (Korea, Republic of); Song, Soon-Young; Koo, Ja Hong [Kwandong Univ. College of Medicine, Myungji Hospital, Seoul (Korea, Republic of); Kim, Man Deuk [College of Medicine Pochon CHA Univ., Seoul (Korea, Republic of)

    2001-10-01

    To review reversible posterior leukoencephalopathy syndrome. We reviewed 22 patients (M:F=3:19; age, 17-46 years) with the characteristic clinical and imaging features of reversible posterior leukoencephalopathy syndrome. All underwent brain MRI, and in three cases both CT and MRI were performed. In one, MRA was obtained, and in eleven, follow-up MR images were obtained. We evaluated the causes of this syndrome, its clinical manifestations, and MR findings including the locations of lesions, the presence or absence of contrast enhancement, and the changes seen at follow-up MRI. Of the 22 patients, 13 had eclampsia (six during pregnancy and seven during puerperium). Four were receiving immunosuppressive therapy (three, cyclosporine ; one, FK 506). Four suffered renal failure and one had complicated migraine. The clinical manifestations included headache (n=12), visual disturbance (n=13), seizure (n=15), focal neurologic sign (n=3), and altered mental status (n=2). Fifteen patients had hypertension and the others normotension. MRI revealed that lesions were bilateral (n=20) or unilateral (n=2). In all patients the lesion was found in the cortical and subcortical areas of the parieto-occipital lobes ; other locations were the basal ganglia (n=9), posterior temporal lobe (n=8), frontal lobe (n=5), cerebellum (n=5), pons (n=2), and thalamus (n=1). All lesions were of high signal intensity on T2-weighted images, and of iso to low intensity on T1-weighted images. One was combined with acute hematoma in the left basal ganglia. In eight of 11 patients who underwent postcontrast T1-weighted MRI, there was no definite enhancement ; in one, enhancement was mild, and in tow, patchy. CT studies showed low attenuation, and MRA revealed mild vasospasm. The symptoms of all patients improved. Follow-up MRI in nine of 11 patients depicted complete resolution of the lesions ; in two, small infarctions remained but the extent of the lesions had decreased. Reversible posterior

  1. Enhancing Rotational Diffusion Using Oscillatory Shear

    KAUST Repository

    Leahy, Brian D.

    2013-05-29

    Taylor dispersion - shear-induced enhancement of translational diffusion - is an important phenomenon with applications ranging from pharmacology to geology. Through experiments and simulations, we show that rotational diffusion is also enhanced for anisotropic particles in oscillatory shear. This enhancement arises from variations in the particle\\'s rotation (Jeffery orbit) and depends on the strain amplitude, rate, and particle aspect ratio in a manner that is distinct from the translational diffusion. This separate tunability of translational and rotational diffusion opens the door to new techniques for controlling positions and orientations of suspended anisotropic colloids. © 2013 American Physical Society.

  2. Shear reinforced beams in autoclaved aerated concrete

    DEFF Research Database (Denmark)

    Cornelius, Thomas

    2010-01-01

    Shear behaviour in concrete materials is very well documented, for normal density concrete materials. In this paper results of various tests on low density concrete materials like aerated autoclaved concrete (in the following denoted aircrete) will be presented and analyzed for different combinat......Shear behaviour in concrete materials is very well documented, for normal density concrete materials. In this paper results of various tests on low density concrete materials like aerated autoclaved concrete (in the following denoted aircrete) will be presented and analyzed for different...

  3. Shear viscosity coefficient of liquid lanthanides

    Energy Technology Data Exchange (ETDEWEB)

    Patel, H. P., E-mail: patel.harshal2@gmail.com; Thakor, P. B., E-mail: pbthakore@rediffmail.com; Prajapati, A. V., E-mail: anand0prajapati@gmail.com [Department of Physics, Veer Narmad South Gujarat University, Surat 395 007, Gujarat (India); Sonvane, Y. A., E-mail: yas@ashd.svnit.ac.in [Department of Applied Physics, S. V. National Institute of Technology, Surat 395 007, Gujarat (India)

    2015-05-15

    Present paper deals with the computation of shear viscosity coefficient (η) of liquid lanthanides. The effective pair potential v(r) is calculated through our newly constructed model potential. The Pair distribution function g(r) is calculated from PYHS reference system. To see the influence of local field correction function, Hartree (H), Tailor (T) and Sarkar et al (S) local field correction function are used. Present results are compared with available experimental as well as theoretical data. Lastly, we found that our newly constructed model potential successfully explains the shear viscosity coefficient (η) of liquid lanthanides.

  4. A discrete finite element modelling and measurements for powder compaction

    International Nuclear Information System (INIS)

    Choi, J L; Gethin, D T

    2009-01-01

    An experimental investigation into friction between powder and a target surface together with numerical modelling of compaction and friction processes at a micro-scale are presented in this paper. The experimental work explores friction mechanisms by using an extended sliding plate apparatus operating at low load while sliding over a long distance. Tests were conducted for copper and 316 steel with variation in loads, surface finish and its orientation. The behaviours of the static and dynamic friction were identified highlighting the important influence of particle size, particle shape, material response and surface topography. The results also highlighted that under light loading the friction coefficient remains at a level lower than that derived from experiments on equipment having a wider dynamic range and this is attributed to the enhanced sensitivity of the measurement equipment. The results also suggest that friction variation with sliding distance is a consequence of damage, rather than presentation of an uncontaminated target sliding surface. The complete experimental cycle was modelled numerically using a combined discrete and finite element scheme enabling exploration of mechanisms that are defined at the particle level. Using compaction as the starting point, a number of simulation factors and process parameters were investigated. Comparisons were made with previously published work, showing reasonable agreement and the simulations were then used to explore the process response to the range of particle scale factors. Models comprising regular packing of round particles exhibited stiff response with high initial density. Models with random packing were explored and were found to reflect trends that are more closely aligned with experimental observation, including rearrangement, followed by compaction under a regime of elastic then plastic deformation. Numerical modelling of the compaction stage was extended to account for the shearing stage of the

  5. Hysteretic Models Considering Axial-Shear-Flexure Interaction

    Science.gov (United States)

    Ceresa, Paola; Negrisoli, Giorgio

    2017-10-01

    Most of the existing numerical models implemented in finite element (FE) software, at the current state of the art, are not capable to describe, with enough reliability, the interaction between axial, shear and flexural actions under cyclic loading (e.g. seismic actions), neglecting crucial effects for predicting the nature of the collapse of reinforced concrete (RC) structural elements. Just a few existing 3D volume models or fibre beam models can lead to a quite accurate response, but they are still computationally inefficient for typical applications in earthquake engineering and also characterized by very complex formulation. Thus, discrete models with lumped plasticity hinges may be the preferred choice for modelling the hysteretic behaviour due to cyclic loading conditions, in particular with reference to its implementation in a commercial software package. These considerations lead to this research work focused on the development of a model for RC beam-column elements able to consider degradation effects and interaction between the actions under cyclic loading conditions. In order to develop a model for a general 3D discrete hinge element able to take into account the axial-shear-flexural interaction, it is necessary to provide an implementation which involves a corrector-predictor iterative scheme. Furthermore, a reliable constitutive model based on damage plasticity theory is formulated and implemented for its numerical validation. Aim of this research work is to provide the formulation of a numerical model, which will allow implementation within a FE software package for nonlinear cyclic analysis of RC structural members. The developed model accounts for stiffness degradation effect and stiffness recovery for loading reversal.

  6. Microstructure analysis of laboratory and in-situ compacted silts

    Directory of Open Access Journals (Sweden)

    Russo Giacomo

    2016-01-01

    Full Text Available The paper presents and discusses some results of an experimental research aimed at analysing the influence of compaction variables (w and energy and method on the resulting microstructure of a compacted silty soil. In particular, the experimental data here discussed allow to compare the microstructure induced by different dynamic compaction techniques, comparing that characterising specimens obtained by two laboratory methods (Proctor standard and Harvard and that of samples compacted in-situ during the construction of an embankment built for river regimentation purposes. Both undisturbed and disturbed samples have been retrieved from the embankment, the latter one with the purpose of collecting the soil subsequently used for laboratory compaction. Microstructural analyses (SEM, MIP performed on laboratory and in-situ compacted samples evidenced a substantial similarity of the texture induced by the various compaction techniques, highlighting that laboratory compaction is suitable to provide soil samples representative of earth in-situ compacted soil.

  7. Compaction Scale Up and Optimization of Cylindrical Fuel Compacts for the Next Generation Nuclear Plant

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey J. Einerson; Jeffrey A. Phillips; Eric L. Shaber; Scott E. Niedzialek; W. Clay Richardson; Scott G. Nagley

    2012-10-01

    Multiple process approaches have been used historically to manufacture cylindrical nuclear fuel compacts. Scale-up of fuel compacting was required for the Next Generation Nuclear Plant (NGNP) project to achieve an economically viable automated production process capable of providing a minimum of 10 compacts/minute with high production yields. In addition, the scale-up effort was required to achieve matrix density equivalent to baseline historical production processes, and allow compacting at fuel packing fractions up to 46% by volume. The scale-up approach of jet milling, fluid-bed overcoating, and hot-press compacting adopted in the U.S. Advanced Gas Reactor (AGR) Fuel Development Program involves significant paradigm shifts to capitalize on distinct advantages in simplicity, yield, and elimination of mixed waste. A series of designed experiments have been completed to optimize compaction conditions of time, temperature, and forming pressure using natural uranium oxycarbide (NUCO) fuel. Results from these experiments are included. The scale-up effort is nearing completion with the process installed and operational using nuclear fuel materials. The process is being certified for manufacture of qualification test fuel compacts for the AGR-5/6/7 experiment at the Advanced Test Reactor (ATR) at the Idaho National Laboratory (INL).

  8. Reverse photoacoustic standoff spectroscopy

    Science.gov (United States)

    Van Neste, Charles W [Kingston, TN; Senesac, Lawrence R [Knoxville, TN; Thundat, Thomas G [Knoxville, TN

    2011-04-12

    A system and method are disclosed for generating a reversed photoacoustic spectrum at a greater distance. A source may emit a beam to a target and a detector measures signals generated as a result of the beam being emitted on the target. By emitting a chopped/pulsed light beam to the target, it may be possible to determine the target's optical absorbance by monitoring the intensity of light collected at the detector at different wavelengths. As the wavelength of light is changed, the target may absorb or reject each optical frequency. Rejection may increase the intensity at the sensing element and absorption may decrease the intensity. Accordingly, an identifying spectrum of the target may be made with the intensity variation of the detector as a function of illuminating wavelength.

  9. Reverse Osmosis Optimization

    Energy Technology Data Exchange (ETDEWEB)

    McMordie Stoughton, Kate; Duan, Xiaoli; Wendel, Emily M.

    2013-08-26

    This technology evaluation was prepared by Pacific Northwest National Laboratory on behalf of the U.S. Department of Energy’s Federal Energy Management Program (FEMP). ¬The technology evaluation assesses techniques for optimizing reverse osmosis (RO) systems to increase RO system performance and water efficiency. This evaluation provides a general description of RO systems, the influence of RO systems on water use, and key areas where RO systems can be optimized to reduce water and energy consumption. The evaluation is intended to help facility managers at Federal sites understand the basic concepts of the RO process and system optimization options, enabling them to make informed decisions during the system design process for either new projects or recommissioning of existing equipment. This evaluation is focused on commercial-sized RO systems generally treating more than 80 gallons per hour.¬

  10. Reverse Osmosis Optimization

    Energy Technology Data Exchange (ETDEWEB)

    None

    2013-08-01

    This technology evaluation was prepared by Pacific Northwest National Laboratory on behalf of the U.S. Department of Energy’s Federal Energy Management Program (FEMP). The technology evaluation assesses techniques for optimizing reverse osmosis (RO) systems to increase RO system performance and water efficiency. This evaluation provides a general description of RO systems, the influence of RO systems on water use, and key areas where RO systems can be optimized to reduce water and energy consumption. The evaluation is intended to help facility managers at Federal sites understand the basic concepts of the RO process and system optimization options, enabling them to make informed decisions during the system design process for either new projects or recommissioning of existing equipment. This evaluation is focused on commercial-sized RO systems generally treating more than 80 gallons per hour.

  11. Reverse osmosis application studies

    International Nuclear Information System (INIS)

    Golomb, A.

    1982-02-01

    To assess the feasibility of applying reverse osmosis (RO) and ultrafiltration (UF) for effective treatment of process and waste streams from operations at Ontario Hydro's thermal and nuclear stations, an extensive literature survey has been carried out. It is concluded that RO is not at present economic for pretreatment of Great Lakes water prior to ion exchange demineralization for boiler makeup. Using both conventional and novel commercial membrane modules, RO pilot studies are recommended for treatment of boiler cleaning wastes, fly ash leachates, and flue gas desulphurization scrubber discharges for removal of heavy metals. Volume reduction and decontamination of nuclear station low-level active liquid waste streams by RO/UF also appear promising. Research programmes are proposed

  12. Sex Reversal in Amphibians.

    Science.gov (United States)

    Flament, Stéphane

    2016-01-01

    Amphibians have been widely used to study developmental biology due to the fact that embryo development takes place independently of the maternal organism and that observations and experimental approaches are easy. Some amphibians like Xenopus became model organisms in this field. In the first part of this article, the differentiation of the gonads in amphibians and the mechanisms governing this process are reviewed. In the second part, the state of the art about sex reversal, which can be induced by steroid hormones in general and by temperature in some species, is presented. Also information about pollutants found in the environment that could interfere with the development of the amphibian reproductive apparatus or with their reproductive physiology is given. Such compounds could play a part in the amphibian decline, since in the wild, many amphibians are endangered species. © 2016 S. Karger AG, Basel.

  13. Mesoscale hydrodynamic modeling of a colloid in shear-thinning viscoelastic fluids under shear flow.

    Science.gov (United States)

    Ji, Shichen; Jiang, Run; Winkler, Roland G; Gompper, Gerhard

    2011-10-07

    In order to study the dynamics of colloidal suspensions with viscoelastic solvents, a simple mesoscopic model of the solvent is required. We propose to extend the multiparticle collision dynamics (MPC) technique--a particle-based simulation method, which has been successfully applied to study the hydrodynamic behavior of many complex fluids with Newtonian solvent--to shear-thinning viscoelastic solvents. Here, the normal MPC particles are replaced by dumbbells with finite-extensible nonlinear elastic (FENE) springs. We have studied the properties of FENE-dumbbell fluids under simple shear flow with shear rate ̇γ. The stress tensor is calculated, and the viscosity η and the first normal-stress coefficient Ψ(1) are obtained. Shear-thinning behavior is found for reduced shear rates Γ= ̇γτ>1, where τ is a characteristic dumbbell relaxation time. Here, both η and Ψ(1) display power-law behavior in the shear-thinning regime. Thus, the FENE-dumbbell fluid with MPC collisions provides a good description of viscoelastic fluids. As a first application, we study the flow behavior of a colloid in a shear-thinning viscoelastic fluid in two dimensions. A slowing down of the colloid rotation in a viscoelastic fluid compared to a Newtonian fluid is obtained, in agreement with recent numerical calculations and experimental results. © 2011 American Institute of Physics

  14. Shear thinning and shear thickening of a confined suspension of vesicles

    Science.gov (United States)

    Nait Ouhra, A.; Farutin, A.; Aouane, O.; Ez-Zahraouy, H.; Benyoussef, A.; Misbah, C.

    2018-01-01

    Widely regarded as an interesting model system for studying flow properties of blood, vesicles are closed membranes of phospholipids that mimic the cytoplasmic membranes of red blood cells. In this study we analyze the rheology of a suspension of vesicles in a confined geometry: the suspension, bound by two planar rigid walls on each side, is subject to a shear flow. Flow properties are then analyzed as a function of shear rate γ ˙, the concentration of the suspension ϕ , and the viscosity contrast λ =ηin/ηout , where ηin and ηout are the fluid viscosities of the inner and outer fluids, respectively. We find that the apparent (or effective viscosity) of the suspension exhibits both shear thinning (decreasing viscosity with shear rate) or shear thickening (increasing viscosity with shear rate) in the same concentration range. The shear thinning or thickening behaviors appear as subtle phenomena, dependant on viscosity contrast λ . We provide physical arguments on the origins of these behaviors.

  15. Acute shear stress direction dictates adherent cell remodeling and verifies shear profile of spinning disk assays

    International Nuclear Information System (INIS)

    Fuhrmann, Alexander; Engler, Adam J

    2015-01-01

    Several methods have been developed to quantify population level changes in cell attachment strength given its large heterogeneity. One such method is the rotating disk chamber or ‘spinning disk’ in which a range of shear forces are applied to attached cells to quantify detachment force, i.e. attachment strength, which can be heterogeneous within cell populations. However, computing the exact force vectors that act upon cells is complicated by complex flow fields and variable cell morphologies. Recent observations suggest that cells may remodel their morphology and align during acute shear exposure, but contrary to intuition, shear is not orthogonal to the radial direction. Here we theoretically derive the magnitude and direction of applied shear and demonstrate that cells, under certain physiological conditions, align in this direction within minutes. Shear force magnitude is also experimentally verified which validates that for spread cells shear forces and not torque or drag dominate in this assay, and demonstrates that the applied force per cell area is largely independent of initial morphology. These findings suggest that direct quantified comparison of the effects of shear on a wide array of cell types and conditions can be made with confidence using this assay without the need for computational or numerical modeling. (paper)

  16. Microstructural Origins of Nonlinear Response in Associating Polymers under Oscillatory Shear

    Directory of Open Access Journals (Sweden)

    Mark A. Wilson

    2017-10-01

    Full Text Available The response of associating polymers with oscillatory shear is studied through large-scale simulations. A hybrid molecular dynamics (MD, Monte Carlo (MC algorithm is employed. Polymer chains are modeled as a coarse-grained bead-spring system. Functionalized end groups, at both ends of the polymer chains, can form reversible bonds according to MC rules. Stress-strain curves show nonlinearities indicated by a non-ellipsoidal shape. We consider two types of nonlinearities. Type I occurs at a strain amplitude much larger than one, type II at a frequency at which the elastic storage modulus dominates the viscous loss modulus. In this last case, the network topology resembles that of the system at rest. The reversible bonds are broken and chains stretch when the system moves away from the zero-strain position. For type I, the chains relax and the number of reversible bonds peaks when the system is near an extreme of the motion. During the movement to the other extreme of the cycle, first a stress overshoot occurs, then a yield accompanied by shear-banding. Finally, the network restructures. Interestingly, the system periodically restores bonds between the same associating groups. Even though major restructuring occurs, the system remembers previous network topologies.

  17. Proposal for FRX-C and multiple-cell Compact Torus experiments

    Energy Technology Data Exchange (ETDEWEB)

    Dreicer, H.

    1979-10-01

    A Compact Torus (CT) is a configuration for plasma confinement that offers possible engineering advantages for fusion power generation such as small size, simple blanket geometry, natural divertor, and spatially separable functions of plasma production and fusion energy generation. Two experiments to study the physics and technology of some particular CT configurations are proposed here as part of the LASL Compact Torus Program Plan. One experiment, FRX-C, is designed to study CT stability and transport properties by scaling the parameters of the existing FRX-B field-reversed theta-pinch experiment to higher temperatures, larger size, and increased plasma lifetime. The second experiment, a modification of the existing Scylla IV-P device, would form a linear array of CTs with the aim of understanding the effect on CT transport of improved plasma confinement on the open field lines outside the separatrix, as well as other multiple-cell effects.

  18. EPRI compact analyzer: A compact, interactive and color-graphics based simulator for power plant analysis

    International Nuclear Information System (INIS)

    Ipakchi, A.; Khadem, M.; Chen, H.; Colley, R.W.

    1986-01-01

    This paper presents the results of an EPRI sponsored project (RP2395-2) for design and development of an interactive, and color graphics based simulator for power plant analysis. The system is called Compact Analyzer and can be applied to engineering and training applications in the utility industry. The Compact Analyzer's software and system design are described. Results of two demonstration system for a nuclear plant, and a fossil plant are presented, and the applications of the Compact Analyzer to operating procedures evaluation are discussed

  19. Test and Analysis of a New Ductile Shear Connection Design for RC Shear Walls

    DEFF Research Database (Denmark)

    Sørensen, Jesper Harrild; Hoang, Linh Cao; Olesen, John Forbes

    2017-01-01

    This paper presents a new and construction-friendly shear connection for assembly of precast reinforced concrete shear wall elements. In the proposed design, the precast elements have indented interfaces and are connected by a narrow zone grouted with mortar and reinforced with overlapping U......-bar loops. Contrary to the classical shear connections, the planes of the U-bar loops are here parallel to the plane of the wall elements. This feature enables a construction-friendly installation of the elements without the risk of rebars clashing. The core of mortar inside each U-bar loop is reinforced...

  20. Analysis of the Shear Behavior of Stubby Y-Type Perfobond Rib Shear Connectors for a Composite Frame Structure.

    Science.gov (United States)

    Kim, Sang-Hyo; Kim, Kun-Soo; Lee, Do-Hoon; Park, Jun-Seung; Han, Oneil

    2017-11-22

    Shear connectors are used in steel beam-concrete slabs of composite frame and bridge structures to transfer shear force according to design loads. The existing Y-type perfobond rib shear connectors are designed for girder slabs of composite bridges. Therefore, the rib and transverse rebars of the conventional Y-type perfobond rib shear connectors are extremely large for the composite frames of building structures. Thus, this paper proposes stubby Y-type perfobond rib shear connectors, redefining the existing connectors, for composite frames of building structures; these were used to perform push-out tests. These shear connectors have relatively small ribs compared to the conventional Y-type perfobond rib shear connectors. To confirm the shear resistance of these stubby shear connectors, we performed an experiment by using transverse rebars D13 and D16. The results indicate that these shear connectors have suitable shear strength and ductility for application in composite frame structures. The shear strengths obtained using D13 and D16 were not significantly different. However, the ductility of the shear connectors with D16 was 45.1% higher than that of the shear connectors with D13.