Introduction to Pinch Technology

DEFF Research Database (Denmark)

Rokni, Masoud

? How to put energy efficiency and other targets like reducing emissions, increasing plant capacities, improve product qualities etc, into a one coherent strategic plan for the overall site? All these questions and more can be answered with a full understanding of Pinch Technology and an awareness...... of the available tools for applying it in a practical way. The aim here is to provide the basic knowledge of pinch technology concept and how it can be applied across a wide range of process industries. The pinch technology was proposed firstly for optimization of heat exchangers and therefore it is introduced...

Characterization of laser-cut copper foil X-pinches

Science.gov (United States)

Collins, G. W.; Valenzuela, J. C.; Hansen, S. B.; Wei, M. S.; Reed, C. T.; Forsman, A. C.; Beg, F. N.

2016-10-01

Quantitative data analyses of laser-cut Cu foil X-pinch experiments on the 150 ns quarter-period, ˜250 kA GenASIS driver are presented. Three different foil designs are tested to determine the effects of initial structure on pinch outcome. Foil X-pinch data are also presented alongside the results from wire X-pinches with comparable mass. The X-ray flux and temporal profile of the emission from foil X-pinches differed significantly from that of wire X-pinches, with all emission from the foil X-pinches confined to a ˜3 ns period as opposed to the delayed, long-lasting electron beam emission common in wire X-pinches. Spectroscopic data show K-shell as well as significant L-shell emission from both foil and wire X-pinches. Fits to synthetic spectra using the SCRAM code suggest that pinching foil X's produced a ˜1 keV, ne ≥ 1023 cm-3 plasma. The spectral data combined with the improved reliability of the source timing, flux, and location indicate that foil X-pinches generate a reproducible, K-shell point-projection radiography source that can be easily modified and tailored to suit backlighting needs across a variety of applications.

Parameter study of a screw-pinch reactor with circular cross-section

International Nuclear Information System (INIS)

Bustraan, M.; Franken, W.M.P.; Klippel, H.Th.; Muysken, M.; Verschuur, K.A.

1977-04-01

In the framework of system studies on pulsed high-β fusion reactors, a parameter study of a reactor based on a screw pinch with a circular cross-section has been performed. The plasma is heated to ignition in two stages. First, the cold plasma is heated by fast implosion in order to guarantee pitch conservation of the inward moving magnetic field lines. The relevant implosion theory has been generalized to a β<1 plasma. In the second stage, an adiabatic compression heats the plasma to the ignition temperature at which point α-particle heating takes over. For stability reasons, β is kept below 0.25. The choice of a particular set of basic parameter values is justified by global design considerations of the reactor. These considerations, e.g. on blanket design and electrotechnical requirements, are presented in some detail. A computer program searches for optimal reactors, i.e. for which at a given thermal output the net efficiency is a maximum. The parameters of a Reference Screw-Pinch Reactor and some other numerical examples are given. The main conclusions are: the net efficiency, although increasing with output energy, is low because of ohmic losses in the compression coil system; the application of sustained fields generated by superconducting coils to reduce these ohmic losses is problematical; a belt-shaped screw pinch in which higher values of β may be reached, improves the net efficiency and alleviates the technical requirements; heating by implosion and adiabatic compression of a plasma with values of β as low as considered here, is inefficient. Therefore, other means of heating the plasma to ignition may be attractive

Measurements of high-current electron beams from X pinches and wire array Z pinches

International Nuclear Information System (INIS)

Shelkovenko, T. A.; Pikuz, S. A.; Blesener, I. C.; McBride, R. D.; Bell, K. S.; Hammer, D. A.; Agafonov, A. V.; Romanova, V. M.; Mingaleev, A. R.

2008-01-01

Some issues concerning high-current electron beam transport from the X pinch cross point to the diagnostic system and measurements of the beam current by Faraday cups are discussed. Results of computer simulation of electron beam propagation from the pinch to the Faraday cup give limits for the measured current for beams having different energy spreads. The beam is partially neutralized as it propagates from the X pinch to a diagnostic system, but within a Faraday cup diagnostic, space charge effects can be very important. Experimental results show evidence of such effects.

Lower pinch radius limit in EXTRAP

International Nuclear Information System (INIS)

Lehnert, B.

1989-01-01

In an Extrap pinch there is a superimposed magnetic octupole field which forms a magnetic separatrix with the field generated by the pinch current. Earlier experiments have shown that the octupole field has a stabilizing influence on the plasma. Regardless of the details of this stabilizing mechanism, it is expected that the influence of the octupole field should become negligible for a sufficiently small ratio between the characteristic pinch and separatrix radii. In other words, there should exist a lower limit of this ratio below which the system approaches the state of an ordinary unstabilized Z-pinch. The present paper presents an extended version of an earlier theoretical model of this lower limit, and its relation to the corresponding critical ratio between the external conductor and pinch currents. This ratio is found to vary substantially with the plasma parameters. (authors)

Plasma sheath dynamics in pinch discharge

International Nuclear Information System (INIS)

Mansour, A.A.Abd-Fattah

1995-01-01

The main interest of the study was to understand the dynamic and to determine the plasma parameters in the 3.5 meter θ-pinch discharge. The 3.5 meter thetatron plasma device has been reconstructed and developed which consist of four capacitor banks: a) Main pinch capacitor bank, (θ-pinch bank) consists of 40 capacitors connected in parallel each of 1.5 μ F., with maximum energy equal to 48 k Joule. b) Preionization capacitor bank (z-pinch) consists of capacitors connected in series each of 1.5μ F., with maximum energy to 0.94 k Joule. c) Bias field bank consists of 4 capacitors connected in parallel each of 38μ F., with maximum energy equal to 4.46 k Joule. d) Screw pinch capacitor bank consists of 5 capacitors connected in parallel each of 1.5μ F., with maximum energy equal to 6 k Joule

Pinch-off Scaling Law of Soap Bubbles

Science.gov (United States)

Davidson, John; Ryu, Sangjin

2014-11-01

Three common interfacial phenomena that occur daily are liquid drops in gas, gas bubbles in liquid and thin-film bubbles. One aspect that has been studied for these phenomena is the formation or pinch-off of the drop/bubble from the liquid/gas threads. In contrast to the formation of liquid drops in gas and gas bubbles in liquid, thin-film bubble pinch-off has not been well documented. Having thin-film interfaces may alter the pinch-off process due to the limiting factor of the film thickness. We observed the pinch-off of one common thin-film bubble, soap bubbles, in order to characterize its pinch-off behavior. We achieved this by constructing an experimental model replicating the process of a human producing soap bubbles. Using high-speed videography and image processing, we determined that the minimal neck radius scaled with the time left till pinch-off, and that the scaling law exponent was 2/3, similar to that of liquid drops in gas.

The physics of fast Z pinches

International Nuclear Information System (INIS)

Ryutov, D.D.; Derzon, M.S.; Matzen, M.K.

1998-07-01

The spectacular progress made during the last few years in reaching high energy densities in fast implosions of annular current sheaths (fast Z pinches) opens new possibilities for a broad spectrum of experiments, from x-ray generation to controlled thermonuclear fusion and astrophysics. Presently Z pinches are the most intense laboratory X ray sources (1.8 MJ in 5 ns from a volume 2 mm in diameter and 2 cm tall). Powers in excess of 200 TW have been obtained. This warrants summarizes the present knowledge of physics that governs the behavior of radiating current-carrying plasma in fast Z-pinches. This survey covers essentially all aspects of the physics of fast Z pinches: initiation, instabilities of the early stage, magnetic Rayleigh-Taylor instability in the implosion phase, formation of a transient quasi-equilibrium near the stagnation point, and rebound. Considerable attention is paid to the analysis of hydrodynamic instabilities governing the implosion symmetry. Possible ways of mitigating these instabilities are discussed. Non-magnetohydrodynamic effects (anomalous resistivity, generation of particle beams, etc.) are summarized. Various applications of fast Z pinches are briefly described. Scaling laws governing development of more powerful Z pinches are presented. The survey contains 52 figures and nearly 300 references

The Physics of Fast Z Pinches

Energy Technology Data Exchange (ETDEWEB)

RYUTOV,D.D.; DERZON,MARK S.; MATZEN,M. KEITH

1999-10-25

The spectacular progress made during the last few years in reaching high energy densities in fast implosions of annular current sheaths (fast Z pinches) opens new possibilities for a broad spectrum of experiments, from x-ray generation to controlled thermonuclear fusion and astrophysics. Presently Z pinches are the most intense laboratory X ray sources (1.8 MJ in 5 ns from a volume 2 mm in diameter and 2 cm tall). Powers in excess of 200 TW have been obtained. This warrants summarizing the present knowledge of physics that governs the behavior of radiating current-carrying plasma in fast Z pinches. This survey covers essentially all aspects of the physics of fast Z pinches: initiation, instabilities of the early stage, magnetic Rayleigh-Taylor instability in the implosion phase, formation of a transient quasi-equilibrium near the stagnation point, and rebound. Considerable attention is paid to the analysis of hydrodynamic instabilities governing the implosion symmetry. Possible ways of mitigating these instabilities are discussed. Non-magnetohydrodynamic effects (anomalous resistivity, generation of particle beams, etc.) are summarized. Various applications of fast Z pinches are briefly described. Scaling laws governing development of more powerful Z pinches are presented. The survey contains 36 figures and more than 300 references.

Determining the resistance of X-pinch plasma

International Nuclear Information System (INIS)

Zhao Shen; Zhu Xin-Lei; Zhang Ran; Luo Hai-Yun; Zou Xiao-Bing; Wang Xin-Xin; Xue Chuang; Ning Cheng; Ding Ning; Shu Xiao-Jian

2013-01-01

The current and the voltage of an X-pinch were measured. The inductance of the X-pinch was assumed to be a constant and estimated by the calculation of the magnetic field based on the well-known Biot—Savart's Law. The voltage of the inductance was calculated with L · di/dt and subtracted from the measured voltage of the X-pinch. Then, the resistance of the X-pinch was determined and the following results were obtained. At the start of the current flow the resistance of the exploding wires is several tens of Ohms, one order of magnitude, higher than the metallic resistance of the wires at room temperature, and then it falls quickly to about 1 Ω, which reflects the physical processes occurring in the electrically exploding wires, i.e., a current transition from the highly resistive wire core to the highly conductive plasma. It was shown that the inductive contribution to the voltage of the X-pinch is less than the resistive contribution. For the wires we used, the wires' material and diameter have no strong influence on the resistance of the X-pinch, which may be explained by the fact that the current flows through the plasma rather than through the metallic wire itself. As a result, the current is almost equally divided between two parallel X-pinches even though the diameter and material of the wires used for these two X-pinches are significantly different. (physics of gases, plasmas, and electric discharges)

An evaluation of a weightlifting belt and back injury prevention training class for airline baggage handlers.

Science.gov (United States)

Reddell, C R; Congleton, J J; Dale Huchingson, R; Montgomery, J F

1992-10-01

This study evaluated the efficacy of a commercially available weightlifting belt in relation to reduction of lumbar injury incident rate and severity of injuries over an 8-month period. The study used 642 baggage handlers working for a major airline company as participants. Four treatment groups were randomly selected: a group receiving the belt only, a group receiving a 1 h training class only, a group receiving both a belt and a 1 h training class, and a control group receiving nothing. Two treatment groups were added which contained participants who discontinued use of the belt prior to the end of an 8-month study period. Results indicated that there were no significant differences for total lumbar injury incident rate, restricted workday case injury incident rate, lost workdays and restricted workdays rate, and worker's compensation rates. There was, however, a marginal significant difference for lost workday case injury incident rate. Groups with participants who wore the belt for a while then discontinued its use had a higher lost day case injury incident rate than did either the group receiving training only or the control group. Compliance was an overriding factor as the belt questionnaire response indicated that 58% of participants in the belt groups discontinued use of the belt before the end of 8 months. Comments made on the survey forms indicated that the belt was too hot. Similarly, comments suggested that the belt rubbed, pinched, and bruised ribs. Based on these results, the weightlifting belt used for this study cannot be recommended for use in aid of lifting during daily work activities of baggage handlers. Results indicate that use of the belts may, in fact, increase the risk of injury when not wearing a belt following a period of wearing a belt. As industries are experimenting with the use of belts, it is recommended that great care be taken in any further evaluation and close attention directed towards injuries which occur when not wearing the

Progress on z-pinch inertial fusion energy

International Nuclear Information System (INIS)

Olson, C.; Rochau, G.; Matzen, M.K.

2005-01-01

The goal of z-pinch inertial fusion energy (IFE) is to extend the single-shot z-pinch inertial confinement fusion (ICF) results on Z to a repetitive-shot z-pinch power plant concept for the economical production of electricity. Z produces up to 1.8 MJ of x-rays at powers as high as 230 TW. Recent target experiments on Z have demonstrated capsule implosion convergence ratios of 14-21 with a double-pinch driven target, and DD neutron yields up to 8x10exp10 with a dynamic hohlraum target. For z-pinch IFE, a power plant concept is discussed that uses high-yield IFE targets (3 GJ) with a low rep-rate per chamber (0.1 Hz). The concept includes a repetitive driver at 0.1 Hz, a Recyclable Transmission Line (RTL) to connect the driver to the target, high-yield targets, and a thick-liquid wall chamber. Recent funding by a U.S. Congressional initiative for $4M for FY04 is supporting research on RTLs, repetitive pulsed power drivers, shock mitigation, full RTL cycle planned experiments, high-yield IFE targets, and z-pinch power plant technologies. Recent results of research in all of these areas are discussed, and a Road Map for Z-Pinch IFE is presented. (author)

History of the Z-pinch

International Nuclear Information System (INIS)

Lovberg, R.H.

1988-01-01

The plasma Z-Pinch occupies a unique position in the history of controlled fusion research as the first confinement and heating scheme to be tried experimentally. In contrast to the sophistication of programs being conducted today, in which extensive theoretical and experimental forces are in close collaboration, early pinch experiments were designed on quite elementary theoretical grounds. Indeed, these systems and the results from them provided the focus for much of the rapid development of theoretical plasma physics and magnetohydrodynamics during the 1950's. In comparison to present programs, these early experiments had the considerable advantage of small size and minimal managerial encumbrance. After nearly three decades of abandonment because of difficulties with MHD instabilities, the Z-pinch is arising once again in a new incarnation characterized by microscopic size and time scales, and very high density. Uniquely in the history of the pinch, the new experimental surprises seem encouraging, rather than discouraging, to the goal of thermonuclear fusion

Z-Pinch Fusion for Energy Applications

Energy Technology Data Exchange (ETDEWEB)

SPIELMAN,RICK B.

2000-01-01

Z pinches, the oldest fusion concept, have recently been revisited in light of significant advances in the fields of plasma physics and pulsed power engineering. The possibility exists for z-pinch fusion to play a role in commercial energy applications. We report on work to develop z-pinch fusion concepts, the result of an extensive literature search, and the output for a congressionally-mandated workshop on fusion energy held in Snowmass, Co July 11-23,1999.

Z-Pinch Fusion for Energy Applications

International Nuclear Information System (INIS)

SPIELMAN, RICK B.

2000-01-01

Z pinches, the oldest fusion concept, have recently been revisited in light of significant advances in the fields of plasma physics and pulsed power engineering. The possibility exists for z-pinch fusion to play a role in commercial energy applications. We report on work to develop z-pinch fusion concepts, the result of an extensive literature search, and the output for a congressionally-mandated workshop on fusion energy held in Snowmass, Co July 11-23,1999

X-ray backlighting of two-wire Z-pinch plasma using X-pinch

International Nuclear Information System (INIS)

Tong, Zhao; Xiao-Bing, Zou; Ran, Zhang; Xin-Xin, Wang

2010-01-01

Two 50-μm Mo wires in parallel used as a Z-pinch load are electrically exploded with a pulsed current rising to 275 kA in 125 ns and their explosion processes are backlighted using an X-pinch as an x-ray source. The backlighting images show clearly the processes similar to those occurring in the initial stages of a cylindrical wire-array Z-pinch, including the electric explosion of single wires characterised by the dense wire cores surrounded by a low-density coronal plasma, the expansion of the exploding wire, the sausage instability (m = 0) in the coronal plasma around each wire, the motion of the coronal plasma as well as the wire core toward the current centroid, the formation of the precursor plasma column with a twist structure something like that of higher mode instability, especially the kink instability (m = 1). (fluids, plasmas and electric discharges)

High-density fusion and the Z-pinch

International Nuclear Information System (INIS)

Hartman, C.W.; Eddleman, J.L.; Munger, R.H.

1975-01-01

The formation of a Z-pinch in dense gas is investigated using numerical modeling in one and two dimensions. Hot, dense Z-pinches are calculated with n approximately 2 x 10 21 cm 3 and T = 10 keV. Relaxation by sausage instability of an unstable pinch profile to a marginally stable one is calculated along with end losses in 2 dimensions to show that, if plasma is confined for N = 50 to 200 sound transits across the radius a, pinches with length L = Na are of interest for fusion power. A conceptual, ''no-wall'' fusion reactor is discussed. (author)

Sheet pinch devices

International Nuclear Information System (INIS)

Anderson, O.A.; Baker, W.R.; Ise, J. Jr.; Kunkel, W.B.; Pyle, R.V.; Stone, J.M.

1958-01-01

Three types of sheet-like discharges are being studied at Berkeley. The first of these, which has been given the name 'Triax', consists of a cylindrical plasma sleeve contained between two coaxial conducting cylinders A theoretical analysis of the stability of the cylindrical sheet plasma predicts the existence of a 'sausage-mode' instability which is, however, expected to grow more slowly than in the case of the unstabilized linear pinch (by the ratio of the radial dimensions). The second pinch device employs a disk shaped discharge with radial current guided between flat metal plates, this configuration being identical to that of the flat hydromagnetic capacitor without external magnetic field. A significant feature of these configurations is the absence of a plasma edge, i.e., there are no regions of sharply curved magnetic field lines anywhere in these discharges. The importance of this fact for stability is not yet fully investigated theoretically. As a third configuration a rectangular, flat pinch tube has been constructed, and the behaviour of a flat plasma sheet with edges is being studied experimentally

Pinch Strengths in Healthy Iranian Children and Young Adult Population

Directory of Open Access Journals (Sweden)

Iman Dianat

2015-03-01

Full Text Available Background: Data on the physical strength capabilities are essential for design-ing safe and usable products and are useful in a wide range of clinical settings especially during treatment of disease affecting the function of the hand. The purpose of this study was to determine peak lateral pinch strength, key pinch strength, tip-to-tip pinch strength and three-jaw pinch strength exertions in a healthy Iranian children and young adult population.Methods: The study was conducted among 511 participants (242 males and 269 females aged 7-30 years. Measurements were carried out with both dominant and non-dominant hands in standard sitting posture using a B&L pinch gauge. Two repetitions of each strength measurement were recorded for each condition and the average value of the two trials was used in the subsequent analysis.Results: The results showed significant differences in the pinch strength data in terms of the age, gender and hand dominance. The lateral pinch strength, key pinch strength, tip-to-tip pinch strength and three-jaw pinch strength exertions by females were 68.4%, 68.8%, 78.8% and 81.8% of those exerted by males, respectively. Strength exertions with the non-dominant hand were 6.4%, 5.2%, 6.6% and 5.1% lower than strength exertions of the dominant hand for the lat-eral pinch strength, key pinch strength, tip-to-tip pinch strength and three-jaw pinch strength exertions, respectively.Conclusion: These findings can be used to fill the gaps in strength data for Iranian population.

The ZaP Flow Z-Pinch Project

International Nuclear Information System (INIS)

Shumlak, U.; Nelson, B. A.

2005-01-01

The results from the ZaP experiment are consistent with the theoretical predictions of sheared flow stabilization. Z pinches with a sheared flow are generated in the ZaP experiment using a coaxial accelerator coupled to an assembly region. The current sheet in the accelerator initially acts as a snowplow. As the Z pinch forms, plasma formation in the accelerator transits to a deflagration process. The plasma exits the accelerator and maintains the flow in the Z pinch. During the quiescent period in the magnetic mode activity at z=0 cm, a stable Z pinch is seen on the axis of the assembly region. The evolution of the axial velocity profile shows a large velocity shear is measured at the edge of the Z pinch during the quiescent period. The velocity shear is above the theoretical threshold. As the velocity shear decreases towards 0.1kV A , the predicted stability threshold, the quiescent period ends. The present understanding of the ZaP experiment shows that it may be possible for the Z pinch to operate in a steady state if the deflagration process can be maintained by constantly supplying neutral gas or plasma to the accelerator

Investigation on the pinch point position in heat exchangers

Science.gov (United States)

Pan, Lisheng; Shi, Weixiu

2016-06-01

The pinch point is important for analyzing heat transfer in thermodynamic cycles. With the aim to reveal the importance of determining the accurate pinch point, the research on the pinch point position is carried out by theoretical method. The results show that the pinch point position depends on the parameters of the heat transfer fluids and the major fluid properties. In most cases, the pinch point locates at the bubble point for the evaporator and the dew point for the condenser. However, the pinch point shifts to the supercooled liquid state in the near critical conditions for the evaporator. Similarly, it shifts to the superheated vapor state with the condensing temperature approaching the critical temperature for the condenser. It even can shift to the working fluid entrance of the evaporator or the supercritical heater when the heat source fluid temperature is very high compared with the absorbing heat temperature. A wrong position for the pinch point may generate serious mistake. In brief, the pinch point should be founded by the iterative method in all conditions rather than taking for granted.

Self-pinched lithium beam transport experiments on SABRE

International Nuclear Information System (INIS)

Hanson, D.L.; Olson, C.L.; Poukey, J.W.; Shokir, I.; Cuneo, M.E.; Menge, P.R.; Johnston, R.R.; Welch, D.R.

1996-01-01

Self-pinched transport of ion beams has many advantages for ion-driven ICF applications involving high yield and energy production. The authors are currently preparing for a self-pinched lithium beam transport experiment on the SABRE accelerator. There are three transport elements that must eventually be demonstrated: (1) efficient lithium beam generation and ballistic transport to a focus at the self-pinched transport channel entrance; (2) self-pinched transport in the channel, requiring optimized injection conditions and gas breakdown; and (3) self-pinched transport of the equilibrated beam from the channel into free space, with associated aiming and stability considerations. In the present experiment, a hollow annular lithium beam from an applied-B extraction ion diode will be focused to small radius (r ≤ 2 cm) in a 60 cm long ballistic focus section containing argon gas at a pressure of a few Torr. The self-pinched transport channel will contain a low pressure background gas of 10--40 mTorr argon to allow sufficient net current to confine the beam for long distance transport. IPROP simulations are in progress to optimize the design of the ballistic and self-pinched transport sections. Progress on preparation of this lithium self-pinched transport experiment, including a discussion of transport system design, important gas breakdown issues, and diagnostics, will be presented

Linear pinch driven by a moving compact torus

International Nuclear Information System (INIS)

Hartman, C.W.; Hammer, J.H.; Eddleman, J.L.

1984-01-01

In principle, a Z-pinch of sufficiently large aspect ratio can provide arbitrarily high magnetic field intensity for the confinement of plasma. In practice, however, achievable field intensities and timescales are limited by parasitic inductances, pulse driver power, current, voltage, and voltage standoff of nearby insulating surfaces or surrounding gas. Further, instabilities may dominate to prevent high fields (kink mode) or enhance them (sausage mode) but in a nonuniform and uncontrollable way. In this paper we discuss an approach to producing a high-field-intensity pinch using a moving compact torus. The moving torus can serve as a very high power driver and may be used to compress a pre-established pinch field, switch on an accelerating pinch field, or may itself be reconfigured to form an intense pinch. In any case, the high energy, high energy density, and high velocity possible with an accelerated compact torus can provide extremely high power to overcome, by a number of orders of magnitude, the limitations to pinch formation described earlier. In this paper we will consider in detail pinches formed by reconfiguration of the compact torus

A summary of the Berkeley and Livermore pinch programs

Energy Technology Data Exchange (ETDEWEB)

Colgate, Stirling A [University of California Radiation Laboratory, Livermore, CA (United States)

1958-07-01

In order to progress toward practical thermonuclear devices, the principal objective must be to prolong containment times by improving the electrical conductivity of the plasma. Those pinch configurations which are grossly unstable are, of course, unsuitable for practical thermonuclear work. Therefore our purely dynamic experiments are conducted only to study basic shock heating and instability mechanisms. Our basic evaluation of progress in pinch-type experiments is the reduction of the dissipation rate of the magnetic fields. The present pessimistic viewpoint is that most of the pinch devices that depend upon high current density within the plasma are beset with an enhanced dissipation rate which is disastrous to pinch containment. This dissipation is derived either from an electron plasma current instability or from hydromagnetic turbulence. Both have been predicted in theory and observed in experiment. Studies have been presented for the following cases: linear and toroidal pinch experiments; sheet pinch devices of modest size; homopolar geometry; shock heating and screw dynamic pinch.

The static pinch

Energy Technology Data Exchange (ETDEWEB)

Longmire, Conrad L [University of California, Los Alamos Scientific Laboratory, Los Alamos, NM (United States)

1958-07-01

In a pinch, the outward diffusion of plasma due to collisions can be balanced by the inward drift resulting from ExB, where E is the applied electric field and B the magnetic field. From the equation expressing the balance of these two effects, together with the pressure balance equation, one obtains the perpendicular conductivity, which is about one-half of the classical parallel conductivity. This result has been applied to the problem of a static pinch under the assumptions: 1) there is an applied longitudinal (B{sub z}) magnetic field; 2) the plasma is isothermal; 3) the solution depends only on the radial coordinate.

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

International Nuclear Information System (INIS)

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

2005-01-01

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

Sausage mode of a high density Z-pinch

International Nuclear Information System (INIS)

Pereira, N.; Rostoker, N.

1983-01-01

In Z-pinch experiments at Maxwell Laboratories, Inc., growth rates have been measured by observing optical emission along the pinch axis. Growth rates estimated by means of the usual model of a pinch involving an incompressible fluid and a surface current are too large by a factor of 2-4. X-ray pinhole photographs generally have the appearance of a series of beads that would be expected from instability of the sausage mode. In some cases, particularly the implosion of large diameter wire arrays with BLACKJACK 5, the beads disappear and only the kink instability is apparent. Generalizing the pinch model to include compressibility does not significantly alter the predictions. A further generalization to include distributed current has therefore been considered. It seems likely that the current can penetrate significantly during the lifetime of the pinch. We consider a model of the pinch that is initially an infinite cylinder. For the sausage mode, stability is determined by a simple second order differential equation together with the boundary condition that follows from the wave number and the frequency of the instability

Nonlinear stage of a Z-pinch instability

International Nuclear Information System (INIS)

Garanin, S.F.; Chernyshev, Y.D.

1987-01-01

The nonlinear evolution of the sausage instability is analyzed for a Z-pinch with a fully developed skin effect in the current. Two-dimensional numerical calculations carried out on the sausage instability show that its occurrence leads to a stage describable by a self-similar solution when the length of the neck is fixed and the plasma compression is isentropic. At a perturbation wavelength small in comparison with the pinch radius, this stage is preceded by a stage which reduces to a nonlinear Rayleigh--Taylor instability. The dynamics of the motion of magnetic field ''bubbles'' and of plasma ''jets'' is analyzed in this case. The plasma jets emerging from the pinch do not block the pinch from the current source

Plasma focus - dense Z pinch and their applications

International Nuclear Information System (INIS)

Ishii, Shozo

1986-02-01

''Workshop on the possibility of Z-pinch as a intense pulse light source'' in 1983 and ''Research meeting on plasma focus and Z-pinch'' in 1984 were held at Institute of Plasma Physics, Nagoya University under a collaborating research program. Research activities reported at the meetings on plasma focus, dense Z-pinch, and related phenomena are summerized. (author)

1/4-pinched contact sphere theorem

DEFF Research Database (Denmark)

Ge, Jian; Huang, Yang

2016-01-01

Given a closed contact 3-manifold with a compatible Riemannian metric, we show that if the sectional curvature is 1/4-pinched, then the contact structure is universally tight. This result improves the Contact Sphere Theorem in [EKM12], where a 4/9-pinching constant was imposed. Some tightness...

Architecture of petawatt-class z-pinch accelerators

International Nuclear Information System (INIS)

Stygar, William A.; Mazarakis, Michael Gerrassimos; Cuneo, Michael Edward; Leeper, Ramon Joe; Ives, H.C.; Headley, D.I.; Wagoner, Tim C.; Porter, John Larry Jr.

2006-01-01

We have developed an accelerator architecture that can serve as the basis of the design of petawatt-class z-pinch drivers. The architecture has been applied to the design of two z-pinch accelerators, each of which can be contained within a 104-m-diameter cylindrical tank. One accelerator is driven by slow (∼1 (micro)s) Marx generators, which are a mature technology but which necessitate significant pulse compression to achieve the short pulses ( 4 capacitors, store 98 MJ, and erect to 5 MV; (ii) 600 water-dielectric triplate intermediate-store transmission lines, which also serve as pulse-forming lines; (iii) 600 5-MV laser-triggered gas switches; (iv) three monolithic radial-transmission-line impedance transformers, with triplate geometries and exponential impedance profiles; (v) a 6-level 5.5-m-diameter 15-MV vacuum insulator stack; (vi) six magnetically insulated vacuum transmission lines (MITLs); and (vii) a triple-post-hole vacuum convolute that adds the output currents of the six MITLs, and delivers the combined current to a z-pinch load. The accelerator delivers an effective peak current of 52 MA to a 10-mm-length z pinch that implodes in 95 ns, and 57 MA to a pinch that implodes in 120 ns. The LTD-driven accelerator includes monolithic radial transformers and a MITL system similar to those described above, but does not include intermediate-store transmission lines, multimegavolt gas switches, or a laser trigger system. Instead, this accelerator is driven by 210 LTD modules that include a total of 1 x 10 6 capacitors and 5 x 10 5 200-kV electrically triggered gas switches. The LTD accelerator stores 182 MJ and produces a peak electrical power of 1000 TW. The accelerator delivers an effective peak current of 68 MA to a pinch that implodes in 95 ns, and 75 MA to a pinch that implodes in 120 ns. Conceptually straightforward upgrades to these designs would deliver even higher pinch currents and faster implosions

Architecture of petawatt-class z-pinch accelerators

Directory of Open Access Journals (Sweden)

W. A. Stygar

2007-03-01

Full Text Available We have developed an accelerator architecture that can serve as the basis of the design of petawatt-class z-pinch drivers. The architecture has been applied to the design of two z-pinch accelerators, each of which can be contained within a 104-m-diameter cylindrical tank. One accelerator is driven by slow (∼1   μs Marx generators, which are a mature technology but which necessitate significant pulse compression to achieve the short pulses (≪1   μs required to drive z pinches. The other is powered by linear transformer drivers (LTDs, which are less mature but produce much shorter pulses than conventional Marxes. Consequently, an LTD-driven accelerator promises to be (at a given pinch current and implosion time more efficient and reliable. The Marx-driven accelerator produces a peak electrical power of 500 TW and includes the following components: (i 300 Marx generators that comprise a total of 1.8×10^{4} capacitors, store 98 MJ, and erect to 5 MV; (ii 600 water-dielectric triplate intermediate-store transmission lines, which also serve as pulse-forming lines; (iii 600 5-MV laser-triggered gas switches; (iv three monolithic radial-transmission-line impedance transformers, with triplate geometries and exponential impedance profiles; (v a 6-level 5.5-m-diameter 15-MV vacuum insulator stack; (vi six magnetically insulated vacuum transmission lines (MITLs; and (vii a triple-post-hole vacuum convolute that adds the output currents of the six MITLs, and delivers the combined current to a z-pinch load. The accelerator delivers an effective peak current of 52 MA to a 10-mm-length z pinch that implodes in 95 ns, and 57 MA to a pinch that implodes in 120 ns. The LTD-driven accelerator includes monolithic radial transformers and a MITL system similar to those described above, but does not include intermediate-store transmission lines, multimegavolt gas switches, or a laser trigger system. Instead, this accelerator is driven by 210

Plasma and current structures in dynamical pinches

International Nuclear Information System (INIS)

Butov, I.Ya.; Matveev, Yu.V.

1981-01-01

Dynamics of plasma layers and current structure in aZ-pinch device has been experimentally investigated. It is found that shaping of a main current envelope is ended with its explosion-like expansion, the pinch decaying after compression to separated current filaments. It is also shown that filling of a region outside the pinch with plasma and currents alternating in directions occurs owing to interaction of current loops (inductions) formed in a magnetic piston during its compression with reflected shock wave. Current circulating in the loops sometimes exceeds 1.5-2 times the current of discharge circuit. The phenomena noted appear during development of superheat instability and can be realized, for example, in theta-pinches, plasma focuses, tokamaks. The experiments were carried out at the Dynamic Zeta-pinch device at an energy reserse of up to 15 kJ (V 0 =24 kV) in a capacitor bank. Half-period of the discharge current is 9 μs; Isub(max)=3.5x10sup(5) A. Back current guide surrounding a china chamber of 28 cm diameter and 50 cm length is made in the form of a hollow cylinder. Initial chamber vacuum is 10 -6 torr [ru

Radiation hydrodynamics of z-pinch plasmas

International Nuclear Information System (INIS)

Davis, J.

1993-01-01

Over the years there has been a sustained interest in and fascination with Z-pinch plasmas. Whether the interest is in radiation source development, fusion plasmas, or basic research there exits an extensive bibliography of literature promulgating and perpetuating a variety of claims regarding the performance of Z-pinch plasmas. In this paper an attempt will be made to present a coherent picture of the documented and commonly held views for a class of Z-pinch plasmas concerned primarily with soft x-ray radiation source development. Many of the issues and findings are common to Z-pinch plasmas in general but the attention here will be focused on gas puffs and multiple wire arrays. The role and importance of radiation on the dynamics and the interplay between the radiation and the dynamics will also be presented and discussed. A number of comparisons with experimental results will be made with 0-, 1-, and 2-D numerical simulations for several pulsed power drivers ranging in current from several mega-amps to 10's of mega-amps for a variety of risetimes and load materials

Hybrid Z-Θ Pinches with fused capacitor banks

International Nuclear Information System (INIS)

Grandey, R.; Gersten, M.; Loter, N.; Rauch, J.; Rostoker, N.; Thompson, W.; Ware, K.

1987-01-01

The Hybrid Z-Θ Pinch circuit equations in the thin shell model were reexamined to see what advantages can be obtained by using a fused, high-energy (>--1MJ) bank driver. The DNA ACE facility at MLI utilizes a 36 μF capacitor band which can be charged to 120 kV to provide 250 kJ of stored energy. This configuration appears to be very appropriate to test the performance of a hybrid-stabilized fused-bank driven pinch. The circuit analyses suggest that the energy transfer efficiency from the bank to a pinched plasma can be increased from less than 1%, for a nonfused bank, to about 10% for a fused configuration. In the applicable region of parameter space, the Hybrid Pinch does not increase the efficiency of energy transfer into the plasma over that obtainable from a Z-pinch. The additional stability may allow larger initial radii to be used with concomitant improved coupling into radiation above 1 keV

Energy balance in a Z pinch with suppressed Rayleigh-Taylor instability

Science.gov (United States)

Baksht, R. B.; Oreshkin, V. I.; Rousskikh, A. G.; Zhigalin, A. S.

2018-03-01

At present Z-pinch has evolved into a powerful plasma source of soft x-ray. This paper considers the energy balance in a radiating metallic gas-puff Z pinch. In this type of Z pinch, a power-law density distribution is realized, promoting suppression of Rayleigh-Taylor (RT) instabilities that occur in the pinch plasma during compression. The energy coupled into the pinch plasma, is determined as the difference between the total energy delivered to the load from the generator and the magnetic energy of the load inductance. A calibrated voltage divider and a Rogowski coil were used to determine the coupled energy and the load inductance. Time-gated optical imaging of the pinch plasma showed its stable compression up to the stagnation phase. The pinch implosion was simulated using a 1D two-temperature radiative magnetohydrodynamic code. Comparison of the experimental and simulation results has shown that the simulation adequately describes the pinch dynamics for conditions in which RT instability is suppressed. It has been found that the proportion of the Ohmic heating in the energy balance of a Z pinch with suppressed RT instability is determined by Spitzer resistance and makes no more than ten percent.

On the instability increments of a stationary pinch

International Nuclear Information System (INIS)

Bud'ko, A.B.

1989-01-01

The stability of stationary pinch to helical modes is numerically studied. It is shown that in the case of a rather fast plasma pressure decrease to the pinch boundary, for example, for an isothermal diffusion pinch with Gauss density distribution instabilities with m=0 modes are the most quickly growing. Instability increments are calculated. A simple analytical expression of a maximum increment of growth of sausage instability for automodel Gauss profiles is obtained

On the Heating of Ions in Noncylindrical Z-Pinches

Science.gov (United States)

Svirsky, E. B.

2018-01-01

The method proposed here for analyzing processes in a hot plasma of noncylindrical Z-pinches is based on separation of the group of high-energy ions into a special fraction. Such ions constitute an insignificant fraction ( 10%) of the total volume of the Z-pinch plasma, but these ions contribute the most to the formation of conditions in which the pinch becomes a source of nuclear fusion products and X-ray radiation. The method allows a quite correct approach to obtaining quantitative estimates of the plasma parameters, the nuclear fusion energy yield, and the features of neutron fluxes in experiments with Z-pinches.

Staged theta pinch experiments

International Nuclear Information System (INIS)

Linford, R.K.; Downing, J.N.; Gribble, R.F.; Jacobson, A.R.; Platts, D.A.; Thomas, K.S.

1976-01-01

Two implosion heating circuits are being experimentally tested. The principal experiment in the program is the 4.5-m-long Staged Theta Pinch (STP). It uses two relatively low energy (50kJ and 100 kJ), high voltage (125 kV) capacitor banks to produce the theta pinch plasma inside the 20 cm i.d. quartz discharge tube. A lower voltage (50 kV), higher energy (750 kJ) capacitor bank is used to contain the plasma and provide a variable amount of adiabatic compression. Because the experiment produces a higher ratio of implosion heating to compressional heating than conventional theta pinches, it should be capable of producing high temperature plasmas with a much larger ratio of plasma radius to discharge tube radius than has been possible in the past. The Resonant Heating Experiment (RHX) in its initial configuration is the same as a 0.9-m-long section of the high voltage part of the STP experiment and all the plasma results here were obtained with the experiment in that configuration. Part of the implosion bank will be removed and a low inductance crowbar added to convert it to the resonant heating configuration. (U.K.)

Parametric dependences of momentum pinch and Prandtl number in JET

DEFF Research Database (Denmark)

Tala, T.; Salmi, A.; Angioni, C.

2011-01-01

Several parametric scans have been performed to study momentum transport on JET. A neutral beam injection modulation technique has been applied to separate the diffusive and convective momentum transport terms. The magnitude of the inward momentum pinch depends strongly on the inverse density...... gradient length, with an experimental scaling for the pinch number being -Rvpinch/χφ = 1.2R/Ln +1.4. There is no dependence of the pinch number on collisionality, whereas the pinch seems to depend weakly on q-profile, the pinch number decreasing with increasing q. The Prandtl number was not found to depend...... either on R/Ln, collisionality or on q. The gyro-kinetic simulations show qualitatively similar dependence of the pinch number on R/Ln, but the dependence is weaker in the simulations. Gyro-kinetic simulations do not find any clear parametric dependence in the Prandtl number, in agreement...

Proposal for the ZT-40 reversed-field Z-pinch experiment

International Nuclear Information System (INIS)

Baker, D.A.; Machalek, M.D.

1977-08-01

A next-generation, toroidal, reversed-field Z-pinch experiment to be constructed at LASL is proposed. On the basis of encouraging ZT-I and ZT-S experimental results, a larger device with a 40-cm bore and a 114-cm major radius is proposed, to extend the confinement time by about an order of magnitude. The new experiment will explore the physics of programming reversed-field pinches in a size range unexplored by previous reversed-field pinch experiments. Model reversed-field pinch reactor calculations show that, if stability is assumed, small fusion reactors are possible if the pinch current density is high. A basic aim will be to delineate the plasma and current density ranges in which stable reversed-field pinches can be produced. Improved vacuum techniques will be used to overcome the radiation losses that probably kept electron temperatures low in the earlier, smaller experiments

Overview of the Fusion Z-Pinch Experiment FuZE

Science.gov (United States)

Weber, T. R.; Shumlak, U.; Nelson, B. A.; Golingo, R. P.; Claveau, E. L.; McLean, H. S.; Tummel, K. K.; Higginson, D. P.; Schmidt, A. E.; UW/LLNL Team

2016-10-01

Previously, the ZaP device, at the University of Washington, demonstrated sheared flow stabilized (SFS) Z-pinch plasmas. Instabilities that have historically plagued Z-pinch plasma confinement were mitigated using sheared flows generated from a coaxial plasma gun of the Marshall type. Based on these results, a new SFS Z-pinch experiment, the Fusion Z-pinch Experiment (FuZE), has been constructed. FuZE is designed to investigate the scaling of SFS Z-pinch plasmas towards fusion conditions. The experiment will be supported by high fidelity physics modeling using kinetic and fluid simulations. Initial plans are in place for a pulsed fusion reactor following the results of FuZE. Notably, the design relies on proven commercial technologies, including a modest discharge current (1.5 MA) and voltage (40 kV), and liquid metal electrodes. Supported by DoE FES, NNSA, and ARPA-E ALPHA.

Kinetic simulation of neutron production in a deuterium z-pinch

International Nuclear Information System (INIS)

Mostrom, C.; Stygar, William A.; Thoma, Carsten; Welch, Dale Robert; Clark, R.E.; Leeper, Ramon Joe; Rose, David V.

2010-01-01

We have found computationally that, at sufficiently high currents, half of the neutrons produced by a deuterium z pinch are thermonuclear in origin. Early experiments below 1-MA current found that essentially all of the neutrons produced by a deuterium pinch are not thermonuclear, but are initiated by an instability that creates beam-target neutrons. Many subsequent authors have supported this result while others have claimed that pinch neutrons are thermonuclear. To resolve this issue, we have conducted fully kinetic, collisional, and electromagnetic simulations of the complete time evolution of a deuterium pinch. We find that at 1-MA pinch currents, most of the neutrons are, indeed, beam-target in origin. At much higher current, half of the neutrons are thermonuclear and half are beam-target driven by instabilities that produce a power law fall off in the ion energy distribution function at large energy. The implications for fusion energy production with such pinches are discussed.

Current redistribution and generation of kinetic energy in the stagnated Z pinch.

Science.gov (United States)

Ivanov, V V; Anderson, A A; Papp, D; Astanovitskiy, A L; Talbot, B R; Chittenden, J P; Niasse, N

2013-07-01

The structure of magnetic fields was investigated in stagnated wire-array Z pinches using a Faraday rotation diagnostic at the wavelength of 266 nm. The distribution of current in the pinch and trailing material was reconstructed. A significant part of current can switch from the main pinch to the trailing plasma preheated by x-ray radiation of the pinch. Secondary implosions of trailing plasma generate kinetic energy and provide enhanced heating and radiation of plasma at stagnation. Hot spots in wire-array Z pinches also provide enhanced radiation of the Z pinch. A collapse of a single hot spot radiates 1%-3% of x-ray energy of the Z pinch with a total contribution of hot spots of 10%-30%.

Finite-Larmor-radius effects on z-pinch stability

Science.gov (United States)

Scheffel, Jan; Faghihi, Mostafa

1989-06-01

The effect of finite Larmor radius (FLR) on the stability of m = 1 small-axial-wavelength kinks in a z-pinch with purely poloidal magnetic field is investigated. We use the incompressible FLR MHD model; a collisionless fluid model that consistently includes the relevant FLR terms due to ion gyroviscosity, Hall effect and electron diamagnetism. With FLR terms absent, the Kadomtsev criterion of ideal MHD, 2r dp/dr + m2B2/μ0 ≥ 0 predicts instability for internal modes unless the current density is singular at the centre of the pinch. The same result is obtained in the present model, with FLR terms absent. When the FLR terms are included, a normal-mode analysis of the linearized equations yields the following results. Marginally unstable (ideal) modes are stabilized by gyroviscosity. The Hall term has a damping (but not absolutely stabilizing) effect - in agreement with earlier work. On specifying a constant current and particle density equilibrium, the effect of electron diamagnetism vanishes. For a z-pinch with parameters relevant to the EXTRAP experiment, the m = 1 modes are then fully stabilized over the crosssection for wavelengths λ/a ≤ 1, where a denotes the pinch radius. As a general z-pinch result a critical line-density limit Nmax = 5 × 1018 m-1 is found, above which gyroviscous stabilization near the plasma boundary becomes insufficient. This limit corresponds to about five Larmor radii along the pinch radius. The result holds for wavelengths close to, or smaller than, the pinch radius and for realistic equilibrium profiles. This limit is far below the required limit for a reactor with contained alpha particles, which is in excess of 1020 m-1.

Finite-Larmor-radius effects on z-pinch stability

Energy Technology Data Exchange (ETDEWEB)

Scheffel, J.; Faghihi, M. (Royal Inst. of Tech., Stockholm (Sweden))

1989-06-01

The effect of finite Larmor radius (FLR) on the stability of m = 1 small-axial-wavelength kinks in a z-pinch with purely poloidal magnetic field is investigated. The incompressible FLR MHD model is used; a collisionless fluid model that consistently includes the relevant FLR terms due to ion gyroviscosity, Hall effect and electron diamagnetism. With FLR terms absent, the Kadomtsev criterion of ideal MHD, 2rdp/dr+m{sup 2}B{sup 2}/{mu}{sub 0}{ge}0 predicts instability for internal modes unless the current density is singular at the centre of the pinch. The same result is obtained in the present model, with FLR terms absent. When the LFR terms are included, a normal-mode analysis of the linearized equations yields the following results. Marginally unstable (ideal) modes are stabilized by gyroviscosity. The Hall term has a damping (but no absolutely stabilizing) effect - in agreement with earlier work. On specifying a constant current and particle density equilibrium, the effect of electron diamagnetism vanishes. For a z-pinch with parameters relevant to the EXTRAP experiment, the m = 1 modes are then fully stabilized over the cross-section for wavelengths {lambda}/{alpha}{le}1, where {alpha} denotes the pinch radius. As a general z-pinch result a critical line-density limit ''N''{sub max}=5x10{sup 18}m{sup -1} is found, above which gyroviscous stabilization near the plasma boundary becomes insufficient. This limit corresponds to about five Larmor radii along the pinch radius. The result holds for wavelengths close to, or smaller than, the pinch radius and for realistic equilibrium profiles. This limit is far below the required limit for a reactor with contained alpha particles, which is in excess of 10{sup 20} m{sup -1}. (author).

Finite-Larmor-radius effects on z-pinch stability

International Nuclear Information System (INIS)

Scheffel, J.; Faghihi, M.

1989-01-01

The effect of finite Larmor radius (FLR) on the stability of m = 1 small-axial-wavelength kinks in a z-pinch with purely poloidal magnetic field is investigated. The incompressible FLR MHD model is used; a collisionless fluid model that consistently includes the relevant FLR terms due to ion gyroviscosity, Hall effect and electron diamagnetism. With FLR terms absent, the Kadomtsev criterion of ideal MHD, 2rdp/dr+m 2 B 2 /μ 0 ≥0 predicts instability for internal modes unless the current density is singular at the centre of the pinch. The same result is obtained in the present model, with FLR terms absent. When the LFR terms are included, a normal-mode analysis of the linearized equations yields the following results. Marginally unstable (ideal) modes are stabilized by gyroviscosity. The Hall term has a damping (but no absolutely stabilizing) effect - in agreement with earlier work. On specifying a constant current and particle density equilibrium, the effect of electron diamagnetism vanishes. For a z-pinch with parameters relevant to the EXTRAP experiment, the m = 1 modes are then fully stabilized over the cross-section for wavelengths λ/α≤1, where α denotes the pinch radius. As a general z-pinch result a critical line-density limit ''N'' max =5x10 18 m -1 is found, above which gyroviscous stabilization near the plasma boundary becomes insufficient. This limit corresponds to about five Larmor radii along the pinch radius. The result holds for wavelengths close to, or smaller than, the pinch radius and for realistic equilibrium profiles. This limit is far below the required limit for a reactor with contained alpha particles, which is in excess of 10 20 m -1 . (author)

Self-similar oscillations of the Extrap pinch

International Nuclear Information System (INIS)

Tendler, M.

1987-11-01

The method of the dynamic stabilization is invoked to explain the enhanced stability of a Z-pinch in EXTRAP configuration. The oscillatory motion is assumed to be forced on EXTRAP due to self-similar oscillations of a Z-pinch. Using a scaling for the net energy loss with plasma density and temperature typical for divertor configurations, a new analytic, self-similar solution of the fluid equations is presented. Strongly unharmonic oscillations of the plasma parameters in the pinch arise. These results are used in a discussion on the stability of EXTRAP, considered as a system with a time dependent internal magnetic field. The effect of the dynamic stabilization is considered by taking estimates. (author)

Performance improvement of centrifugal compressor stage with pinched geometry or vaned diffuser

Energy Technology Data Exchange (ETDEWEB)

Jaatinen, A.

2009-07-01

Centrifugal compressors are widely used for example in refrigeration processes, the oil and gas industry, superchargers, and waste water treatment. In this work, five different vaneless diffusers and six different vaned diffusers are investigated numerically. The vaneless diffusers vary only by their diffuser width, so that four of the geometries have pinch implemented to them. Pinch means a decrease in the diffuser width. Four of the vaned diffusers have the same vane turning angle and a different number of vanes, and two have different vane turning angles. The flow solver used to solve the flow fields is Finfo, which is a Navier-Stokes solver. All the cases are modeled Chien's k-epsilon turbulence model. All five vaneless diffusers and three vaned diffusers are investigated also experimentally. For each construction, the compressor operating map is measured according to relevant standards. In addition to this, the flow fields before and after the diffuser are measured with static and total pressure, flow angle and total temperature measurements k-omega SST turbulence model. The simulation results indicate that it is possible to improve the efficiency with the pinch, and according to the numerical results, the two best geometries are the ones with most pinch at the shroud. These geometries have approximately 4 percentage points higher effciency than the unpinched vaneless diffusers. The hub pinch does not seem to have any major benefits. In general, the pinches make the flow fields before and after the diffuser more uniform. The pinch also seems to improve the impeller effciency. This is down to two reasons. The major reason is that the pinch decreases the size of slow flow and possible backflow region located near the shroud after the impeller. Secondly, the pinches decrease the flow velocity in the tip clearance, leading to a smaller tip leakage flow and therefore slightly better impeller efficiency. Also some of the vaned diffusers improve the efficiency

Acoustic bubble enhanced pinched flow fractionation for microparticle separation

International Nuclear Information System (INIS)

Zhou, Ran; Wang, Cheng

2015-01-01

Pinched flow fractionation is a simple method for separating micron-sized particles by size, but has certain intrinsic limitations, e.g. requirement of a pinched segment similar to particle size and limited separation distance. In this paper, we developed an acoustic bubble enhanced pinched flow fractionation (PFF) method for microparticle separation. The proposed technique utilized microbubble streaming flows to overcome the limitations of conventional PFF. Our device has demonstrated separation of different sized microparticles (diameters 10 and 2 μm) with a larger pinched segment (60 μm) and at different buffer/particle solution flow rate ratios (5–25). The separation distances between particles are larger (as much as twice as large) than those achieved with conventional PFF. In addition, the separation position and distance can be adjusted by changing the driving voltage. The robust performance is due to the unique features of the flow field inside the pinched segment. We investigated several factors, including flow rate ratio, total flow rate and driving voltage, that affect the separation performance. (paper)

Effects of boundary conditions on temperature and density in an EXTRAP Z-pinch

International Nuclear Information System (INIS)

Drake, J.R.; Karlsson, P.

1985-08-01

Using the fluid equations, we examine transport in an Extrap configuration by carrying out calculations incorporating model profiles for the density and temperature. The goal of this analysis is to examine the scaling of the pinch equilibrium plasma density, temperature and radius with parameters that are characteristic for Extrap Z-pinches. These parameters include the discharge current, the neutral hydrogen filling density, an oxygen impurity fractional concentration and the condition at the pinch boundary. An Extrap Z-pinch is a pinch discharge where the current channel has a characteristic non-circular cross-section achieved by bounding the discharge by a magnetic separatrix produced when a vacuum octupole magnetic field, generated by currents in external conductors, combines with the self-magnetic field produced by the discharge current. The pinch boundary is changed from a plasma-vacuum boundary to an interface between a high-beta pinch plasma and a low-beta plasma contained in the vacuum magnetic field. The energy that is lost from the pinch region sustains this boundary layer. The introduction of a separatrix boundary around the pinch with four X-point nulls deteriorates the containment of the pinch somewhat. However the presence of the warm, low-beta plasma scrape-off layer, which provides a boundary condition on the pinch, tends to counteract the negative effects of the poorer confinement. Thus the equilibrium parameters that characterize the pinch may not be severely deteriorated by the introduction of the separatrix when the entire configuration, including the scrape-off layer, is considered. (author)

Experiments on screw-pinch plasmas with elongated cross section

International Nuclear Information System (INIS)

Lassing, H.W.

1989-01-01

In this thesis experiments are described carried out with SPICA II, a toroidal screw-pinch plasma device. this device is the last one in a series of plasma machines of the toroidal screw-pinch differing from its predecessor in its race-track shaped section. In devices of the type toroidal screw-pinch stable confinement is possible of plasmas with larger β values than in a tokamak discharge. In a pinch the plasma is screwed up, during the formation, in such a way that in a relatively small volume a plasma is formated with a high pressure. During the screwing up the plasma is heated by shock heating as well as adiabatic compression. With the modified snowplow model the density and temperature after the formation can be calculated, starting from the initial conditions. When all ions arrive into the plasma column, the density in the column is determined by the volume compression. First purpose of the experiments was to find a stable discharge. Subsequently discharges have been made with a high as possible β in order to investigate at which maximum β it is possible to confine screw-pinch plasmas stably. When these had been found, the nature and importance could be investigated of the processes following which the screw-pinch plasma looses its energy. (author), 75 res.; 95 figs.; 8 tabs

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

International Nuclear Information System (INIS)

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

1999-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1999-07-01

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

Impact of PINCH expression on survival in colorectal cancer patients

International Nuclear Information System (INIS)

Lööf, Jasmine; Rosell, Johan; Bratthäll, Charlotte; Doré, Siv; Starkhammar, Hans; Zhang, Hong; Sun, Xiao-Feng

2011-01-01

The adaptor protein PINCH is overexpressed in the stroma of several types of cancer, and is an independent prognostic marker in colorectal cancer. In this study we further investigate the relationship of PINCH and survival regarding the response to chemotherapy in colorectal cancer. Paraffin-embedded tissue sections from 251 primary adenocarcinomas, 149 samples of adjacent normal mucosa, 57 samples of distant normal mucosa and 75 lymph node metastases were used for immunohistochemical staining. Stromal staining for PINCH increased from normal mucosa to primary tumour to metastasis. Strong staining in adjacent normal mucosa was related to worse survival independently of sex, age, tumour location, differentiation and stage (p = 0.044, HR, 1.60, 95% CI, 1.01-2.52). PINCH staining at the invasive margin tended to be related to survival (p = 0.051). In poorly differentiated tumours PINCH staining at the invasive margin was related to survival independently of sex, age and stage (p = 0.013, HR, 1.90, 95% CI, 1.14-3.16), while in better differentiated tumours it was not. In patients with weak staining, adjuvant chemotherapy was related to survival (p = 0.010, 0.013 and 0.013 in entire tumour area, invasive margin and inner tumour area, respectively), but not in patients with strong staining. However, in the multivariate analysis no such relationship was seen. PINCH staining in normal adjacent mucosa was related to survival. Further, PINCH staining at the tumour invasive margin was related to survival in poorly differentiated tumours but not in better differentiated tumours, indicating that the impact of PINCH on prognosis was dependent on differentiation status

Influence of pinches on magnetic reconnection in turbulent space plasmas

Science.gov (United States)

Olshevsky, Vyacheslav; Lapenta, Giovanni; Markidis, Stefano; Divin, Andrey

A generally accepted scenario of magnetic reconnection in space plasmas is the breakage of magnetic field lines in X-points. In laboratory, reconnection is widely studied in pinches, current channels embedded into twisted magnetic fields. No model of magnetic reconnection in space plasmas considers both null-points and pinches as peers. We have performed a particle-in-cell simulation of magnetic reconnection in a three-dimensional configuration where null-points are present nitially, and Z-pinches are formed during the simulation. The X-points are relatively stable, and no substantial energy dissipation is associated with them. On contrary, turbulent magnetic reconnection in the pinches causes the magnetic energy to decay at a rate of approximately 1.5 percent per ion gyro period. Current channels and twisted magnetic fields are ubiquitous in turbulent space plasmas, so pinches can be responsible for the observed high magnetic reconnection rates.

Experimental studies of the argon-puff Z-pinch implosion process

International Nuclear Information System (INIS)

Huang Xianbin; Yang Libing; Gu Yuanchao; Deng Jianjun; Zhou Rongguo; Zou Jie; Zhou Shaotong; Zhang Siqun; Chen Guanghua; Chang Lihua; Li Fengping; Ouyang Kai; Li Jun; Yang Liang; Wang Xiong; Zhang Zhaohui

2006-01-01

A preliminary experiment for studying the argon-puff Z-pinch implosion process has been performed on the Yang accelerator. The ten-frame nanosecond temporal and spatial gated camera, visible high-speed scanning camera, differential laser interferometer, X-ray time integration pinhole camera and X-ray power system have been used to investigated the evolution of the argon-puff Z-pinch. Some typical results of argon-puff Z-pinch during implosion and pinch phase, including the 'zipper' effect, necking phenomenon, sausage instability, temperature changes and the effect of load current rise time, are given and analyzed as examples, and some relevant conclusions are drawn. (authors)

X-Pinch And Its Applications In X-ray Radiograph

International Nuclear Information System (INIS)

Zou Xiaobing; Wang Xinxin; Liu Rui; Zhao Tong; Zeng Naigong; Zhao Yongchao; Du Yanqiang

2009-01-01

An X-pinch device and the related diagnostics of x-ray emission from X-pinch were briefly described. The time-resolved x-ray measurements with photoconducting diodes show that the x-ray pulse usually consists of two subnanosecond peaks with a time interval of about 0.5 ns. Being consistent with these two peaks of the x-ray pulse, two point x-ray sources of size ranging from 100 μm to 5 μm and depending on cut-off x-ray photon energy were usually observed on the pinhole pictures. The x-pinch was used as x-ray source for backlighting of the electrical explosion of single wire and the evolution of X-pinch, and for phase-contrast imaging of soft biological objects such as a small shrimp and a mosquito.

Determination of plasma Z-pinch effect by intrinsic stimulated emission

International Nuclear Information System (INIS)

Lue, J.T.; Liang, J.M.

1977-01-01

The plasma Z-pinch behavior has been observed in a relatively small-bore diameter tube and low bank voltage discharge system. The instant of the occurrence of the laser line at 4880 A coincides with the plasma pinch time calculated by using a one-fluid snow-plow model. A determination of plasma pinch parameters by measuring the intrinsic stimulated emission of the ions is described

Development of sausage-type instability in a Z-pinch plasma column

International Nuclear Information System (INIS)

Vikhrev, V.V.; Ivanov, V.V.; Rozanova, G.A.

1993-01-01

The development of sausage-type instabilities in an initially homogeneous Z-pinch plasma column has been investigated by means of numerical modelling. It is shown that in the presence of short-wave perturbations of a Z-pinch boundary and a rarefied plasma surrounding the pinch, cavities filled with a rarefied plasma and with a magnetic field are formed in the plasma column. As a result of this cavity growth, small columns of dense plasma form on the axis in the Z-pinch which have a temperature substantially higher than the average plasma temperature in the plasma column. When deuterium is present in the pinch, these dense high temperature bunches can become a source of intensive neutron radiation. (author). 24 refs, 7 figs

ANALYSIS OF POWER GRIP AND PINCH GRIP AMONG HEALTH CARE PROFESSIONALS

Directory of Open Access Journals (Sweden)

Zakariya M P

2016-02-01

Full Text Available Background: Grip and pinch strength are commonly employed indices of strength used in hand evaluations. Pinch grip and power grip strengths are used as indices of strength in hand therapy assessments. For all professions grip strength is an important criterion to be successful in their profession. Such phenomena may be explained by differences in nature of work, working environment, and objects workers handle. Method: 200 healthy subjects, satisfying the selection criteria were included and assessed with standardized procedure for power grip and pinch grip (lateral pinch, pad-pad, and tip-tip strength. They were divided in four groups, 50 group each according to profession i.e. medical surgeons, dentist, physiotherapists and nurses. Results: The mean power grip strength shows highly significant difference between medical vs. dental (p>0.01 and medical vs. physiotherapy group (p> 0.05 .The mean lateral pinch strength shows there is highly significant difference (p< 0.001 between dental vs. nursing profession and dental vs. physiotherapy group. No significant difference among other groups. The mean pad-pad pinch strength shows there is significant difference between dental vs. nursing (p< 0.05 and dental vs physiotherapy group (p< 0.05. The mean Tip-Tip pinch strength shows there is significant difference between dental vs nursing profession(p< 0.05 and dental vs. physiotherapy(p< 0.05. No significant different among other groups. Conclusion: Surgeons have highest power grip strength followed by Nursing, Physiotherapy and Dental professionals. Dentists have the maximum pinch strength in all three positions, followed by Surgeons, Nurses and Physiotherapists. Surgeons have maximum pinch strength next to Dentists.

Experimental studies of an Extrap Z-Pinch

International Nuclear Information System (INIS)

Drake, J.R.

1983-01-01

Experimental studies of the formation, equilibrium and stability of a linear Extrap Z-pinch are reported on. The Z-pinch discharge is generated between electrodes along the Z-axis of a linear octupole field produced by currents in four Z-directed rods. The combined discharge current and rod currents produce a magnetic field having a separatrix with four null X-points which define the corners of a square shaped region where the high beta plasma discharge is contained. Bounding the pinch discharge with a separatrix produces equilibria which are stable against global kink modes for the 50-μsec duration of the discharge which corresponds to about 100 Alfven transit times. The equilibria, with line densities of about 3 x 10 18 m - 1 , are consistent in magnitude and scaling with the Bennet relation. (Author)

Effect of transcranial magnetic stimulation on force of finger pinch

Science.gov (United States)

Odagaki, Masato; Fukuda, Hiroshi; Hiwaki, Osamu

2009-04-01

Transcranial magnetic stimulation (TMS) is used to explore many aspects of brain function, and to treat neurological disorders. Cortical motor neuronal activation by TMS over the primary motor cortex (M1) produces efferent signals that pass through the corticospinal tracts. Motor-evoked potentials (MEPs) are observed in muscles innervated by the stimulated motor cortex. TMS can cause a silent period (SP) following MEP in voluntary electromyography (EMG). The present study examined the effects of TMS eliciting MEP and SP on the force of pinching using two fingers. Subjects pinched a wooden block with the thumb and index finger. TMS was applied to M1 during the pinch task. EMG of first dorsal interosseous muscles and pinch forces were measured. Force output increased after the TMS, and then oscillated. The results indicated that the motor control system to keep isotonic forces of the muscles participated in the finger pinch was disrupted by the TMS.

Scaling of X pinches from 1 MA to 6 MA

International Nuclear Information System (INIS)

Bland, Simon Nicholas; McBride, Ryan D.; Wenger, David Franklin; Sinars, Daniel Brian; Chittenden, Jeremy Paul; Pikuz, Sergei A.; Harding, Eric; Jennings, Christopher A.; Ampleford, David J.; Yu, Edmund P.; Cuneo, Michael Edward; Shelkovenko, Tatiana A.; Hansen, Stephanie B.

2010-01-01

This final report for Project 117863 summarizes progress made toward understanding how X-pinch load designs scale to high currents. The X-pinch load geometry was conceived in 1982 as a method to study the formation and properties of bright x-ray spots in z-pinch plasmas. X-pinch plasmas driven by 0.2 MA currents were found to have source sizes of 1 micron, temperatures >1 keV, lifetimes of 10-100 ps, and densities >0.1 times solid density. These conditions are believed to result from the direct magnetic compression of matter. Physical models that capture the behavior of 0.2 MA X pinches predict more extreme parameters at currents >1 MA. This project developed load designs for up to 6 MA on the SATURN facility and attempted to measure the resulting plasma parameters. Source sizes of 5-8 microns were observed in some cases along with evidence for high temperatures (several keV) and short time durations (<500 ps).

Experimental study of the neck formation in an X pinch

International Nuclear Information System (INIS)

Artyomov, A P; Chaikovsky, S A; Fedunin, A V; Labetskaya, N A; Rousskikh, A G; Zhigalin, A S; Oreshkin, V I

2014-01-01

X-pinch experiments have been performed on a compact 250 kA, 180 ns pulsed power generator specially designed for this purpose at the Institute of High Current Electronics (Tomsk, Russia). The X pinches were composed of two molybdenum wires of diameter 25 μm making an angle of 36° with the z-axis. The X-pinch dynamics was recorded with a 3 ns exposure time using an HSFC Pro four-frame camera. Axial plasma jets propagating toward both the anode and the cathode were observed. The jets became noticeable within 10 ns after the onset of current flow, which approximately corresponded to the time at which the electrical explosion of the X-pinch wires occurred. The velocity of the anode-directed jet reached 10 7 cm/s, which was about 1.5 times the velocity of the cathode-directed jet. These high jet velocities are inconsistent with the plasma temperature resulting from the wire explosion. Hence, these jets seem to develop due to implosion of the light plasma layer stripped by magnetic forces from the wire surface, and the increase in their velocities is perhaps due to cumulative effects taking place at the X-pinch axis. The X-pinch neck formed as a rule above the initial wire cross point (closer to the anode). In this region, the plasma diameter gradually increased with time and then drastically decreased 10-15 ns prior to the x-ray pulse. Immediately before the x-ray pulse, in the (250-300 μm long) plasma neck, a lower scale constriction developed, forming a h ot spot . It has been confirmed that the anode-directed plasma jet could take some part of the X-pinch wire current because of the evident jet pinching in the anode region. This process seems to determine the neck length

Investigation of layered Z-pinches on ANGARA-5-1

Energy Technology Data Exchange (ETDEWEB)

Branitskij, A V; Grabovskij, E V; Zakharov, S V; Zurin, M V; Nedoseev, S L; Olejnik, G M; Smirnov, V P; Frolov, I N [Troitsk Inst. of Innovative and Fusion Research (Russian Federation)

1997-12-31

Experimental results of layered Z-pinch investigations on Angara-5-1 are presented. The level of current was 3-4 MA through a load with a 70-90 ns rise time. The initial-to-final radius ratio increased from 10-15 for a conventional single pinch, up to 30-50 for the double layered design. A power flux of about 8-12 TW/cm{sup 2} was achieved with front rise time about 3 ns. The final pinch diameter was down to 0.5-1 mm. (author). 4 figs., 1 ref.

A Reactor Development Scenario for the FuZE Sheared-Flow Stabilized Z-pinch

Science.gov (United States)

McLean, Harry S.; Higginson, D. P.; Schmidt, A.; Tummel, K. K.; Shumlak, U.; Nelson, B. A.; Claveau, E. L.; Forbes, E. G.; Golingo, R. P.; Stepanov, A. D.; Weber, T. R.; Zhang, Y.

2017-10-01

We present a conceptual design, scaling calculations, and development path for a pulsed fusion reactor based on a flow-stabilized Z-pinch. Experiments performed on the ZaP and ZaP-HD devices have largely demonstrated the basic physics of sheared-flow stabilization at pinch currents up to 100 kA. Initial experiments on the FuZE device, a high-power upgrade of ZaP, have achieved 20 usec of stability at pinch current 100-200 kA and pinch diameter few mm for a pinch length of 50 cm. Scaling calculations based on a quasi-steady-state power balance show that extending stable duration to 100 usec at a pinch current of 1.5 MA and pinch length of 50 cm, results in a reactor plant Q 5. Future performance milestones are proposed for pinch currents of: 300 kA, where Te and Ti are calculated to exceed 1-2 keV; 700 kA, where DT fusion power would be expected to exceed pinch input power; and 1 MA, where fusion energy per pulse exceeds input energy per pulse. This work funded by USDOE ARPA-E and performed under the auspices of Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-734770.

X-ray sources by Z-pinch for inertial confinement fusion

International Nuclear Information System (INIS)

Akiyama, Hidenori; Katsuki, Sunao; Lisitsyn, Igor

1999-01-01

Inertial confinement nuclear fusion driven by X-ray from Z-pinch plasmas has been developed. Recently, extremely high X-ray power (290 TW) and energy (1.8 MJ) were produced in fast Z-pinch implosions on the Z accelerator (Sandia National Laboratories). Wire arrays are used to produce the initial plasma. The X-ray from Z-pinch plasmas produced by pulsed power has great potential as a driver of inertial confinement nuclear fusion. (author)

Engineering prototypes for theta-pinch devices

International Nuclear Information System (INIS)

Hansborough, L.D.; Hammer, C.F.; Hanks, K.W.; McDonald, T.E.; Nunnally, W.C.

1975-01-01

Past, present, and future engineering prototypes for theta-pinch plasma-physics devices at Los Alamos Scientific Laboratory are discussed. Engineering prototypes are designed to test and evaluate all components under system conditions expected on actual plasma-physics experimental devices. The importance of engineering prototype development increases as the size and complexity of the plasma-physics device increases. Past experiences with the Scyllac prototype and the Staged Theta-Pinch prototype are discussed and evaluated. The design of the proposed Staged Scyllac prototype and the Large Staged Scyllac implosion prototype assembly are discussed

Constraints on inner forearc deformation from balanced cross sections, Fila Costeña thrust belt, Costa Rica

Science.gov (United States)

Sitchler, Jason C.; Fisher, Donald M.; Gardner, Thomas W.; Protti, Marino

2007-12-01

The Fila Costeña thrust belt in the forearc of Costa Rica is accommodating a significant portion of the convergence of the Cocos plate and Panama microplate. Geologic mapping of the thrust belt depicts a duplex with three horses that incorporate Eocene limestones and Oligocene to early Miocene clastics inboard of the subducting Cocos Ridge axis. By constructing a cross section at this location along a NE-SW trending transect perpendicular to the thrust belt, we constrain a shortening rate of approximately 40 mm/a and propose that as much as 50% of the total plate convergence rate is taken up in the inner forearc. The Eocene limestones at the base of the thrust sheets pinch out in both directions away from the onland projection of the Cocos Ridge axis owing to decrease in slip on faults and a lateral ramp in the basal décollement. The thrust belt terminates near the Panama border at the onland projection of the subducting Panama Fracture Zone. These observations suggest that shortening is propagating to the east with the migration of the Panama triple junction and the onset of shallow subduction of the thickened edge of the Cocos plate. The absence of similar features in the Nicaraguan forearc, where the subducting crust is older, subducts more steeply, and lacks incoming ridges and seamounts, indicates that deformation of the forearc basin in Costa Rica reflects greater coupling between the converging plates inboard of the Cocos Ridge.

The ZaP Flow Z-Pinch Project - Final Technical Report

Energy Technology Data Exchange (ETDEWEB)

Shumlak, Uri [Univ. of Washington, Seattle, WA (United States); Nelson, Brian A. [Univ. of Washington, Seattle, WA (United States)

2013-12-31

The ZaP Flow Z-Pinch Project is a project to extend the performance of the flow Z-pinch experiment at the University of Washington to investigate and isolate the relevant physics of the stabilizing effect of plasma flow. Experimental plasmas have exhibited an enhanced stability under certain operating parameters which generate a flow state (axial flows in Z-pinches and VH mode in tokamaks). Flow has also been suggested as the stabilizing mechanism in astrophysical jets.

A Reactor Development Scenario for the FUZE Shear-flow Stabilized Z-pinch

Science.gov (United States)

McLean, H. S.; Higginson, D. P.; Schmidt, A.; Tummel, K. K.; Shumlak, U.; Nelson, B. A.; Claveau, E. L.; Golingo, R. P.; Weber, T. R.

2016-10-01

We present a conceptual design, scaling calculations, and a development path for a pulsed fusion reactor based on the shear-flow-stabilized Z-pinch device. Experiments performed on the ZaP device have demonstrated stable operation for 40 us at 150 kA total discharge current (with 100 kA in the pinch) for pinches that are 1cm in diameter and 100 cm long. Scaling calculations show that achieving stabilization for a pulse of 100 usec, for discharge current 1.5 MA, in a shortened pinch 50 cm, results in a pinch diameter of 200 um and a reactor plant Q 5 for reasonable assumptions of the various system efficiencies. We propose several key intermediate performance levels in order to justify further development. These include achieving operation at pinch currents of 300 kA, where Te and Ti are calculated to exceed 1 keV, 700 kA where fusion power exceeds pinch input power, and 1 MA where fusion energy per pulse exceeds input energy per pulse. This work funded by USDOE ARPAe ALPHA Program and performed under the auspices of Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-697801.

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

International Nuclear Information System (INIS)

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

1999-01-01

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

The pinch of cold ions from recycling in the tokamak edge pedestal

International Nuclear Information System (INIS)

Wan Weigang; Parker, Scott E.; Chen Yang; Park, Gun-Young; Chang, Choong-Seock; Stotler, Daren

2011-01-01

We apply the ''natural fueling mechanism'' [W. Wan, S. E. Parker, Y. Chen, and F. W. Perkins, Phys. Plasmas 17, 040701 (2010)] to the edge pedestal. The natural fueling mechanism is where cold ions naturally pinch radially inward for a heat-flux dominated plasma. It is shown from neoclassical-neutral transport coupled simulations that the recycling neutrals and the associated source ions are colder than the main ions in the edge pedestal. These recycling source ions will pinch radially inward due to microturbulence. Gyrokinetic turbulence simulations indicate that near the top of the pedestal, the pinch velocity of the recycling source ions is much higher than the main ion outgoing flow velocity. The turbulent pinch of the recycling source ions may play a role in the edge pedestal transport and dynamics. The cold ion temperature significantly enhances the pinch velocity of the recycling source ions near to the pedestal top. Neoclassical calculations show a cold ion pinch in the pedestal as well.

New developments of belt conveyor systems; Inclined belt systems, vertical pipe elevators, vibration belts, oscillating tubes

Energy Technology Data Exchange (ETDEWEB)

Bahke, E.A. (Universitaet Karlsruhe, Karlsruhe (Germany, F.R.). Inst. fuer Foerdertechnik)

1991-03-01

Factors that have influenced the design of belt conveyor systems are discussed - these include strength and shaping. Belt conveyor systems for inclined, steep-angle and vertical conveying are described and comparison made between cable belt and steel cord belt conveyors used in coal mines. Hose-belt or tube conveyors such as are used in the PWH/Conti-Rollgurt Conveyor System for feeding boilers in German coal fired power stations are mentioned and advantages of the pipe-belt conveyor for vertical transport discussed. Design of the vibratory conveyor for transporting solids upwards by pulses is described. 29 refs., 19 figs., 2 tabs.

Scaling the Shear-flow Stabilized Z-pinch to Reactor Conditions

Science.gov (United States)

McLean, H. S.; Schmidt, A.; Shumlak, U.; Nelson, B. A.; Golingo, R. P.; Cleveau, E.

2015-11-01

We present a conceptual design along with scaling calculations for a pulsed fusion reactor based on the shear-flow-stabilized Z-pinch device. Experiments performed on the ZaP device, at the University of Washington, have demonstrated stable operation for durations of 20 usec at ~100kA discharge current for pinches that are ~1 cm in diameter and 100 cm long. The inverse of the pinch diameter and plasma energy density scale strongly with pinch current and calculations show that maintaining stabilization durations of ~7 usec for increased discharge current (~15x) in a shortened pinch (10 cm) results in a pinch diameter of ~200 um and plasma conditions that approach those needed to support significant fusion burn and energy gain (Ti ~ 30keV, density ~ 3e26/m3, ntau ~1.4e20 sec/m3). Compelling features of the concept include operation at modest discharge current (1.5 MA) and voltage (40kV) along with direct adoption of liquid metals for at least one electrode--technological capabilities that have been proven in existing, commercial, pulse power devices such as large ignitrons. LLNL-ABS-674920. This work performed under the auspices of the U.S. Department of Energy ARPAe ALPHA Program by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Evidence of flow stabilization in the ZaP Z pinch experiment

International Nuclear Information System (INIS)

Shumlak, U.; Crawford, E.; Golingo, R.P.; Nelson, B.A.; Zyrmpas, A.; Den Hartog, D.J.; Holly, D.J.

2001-01-01

The stabilizing effect of an axial flow on the m = 1 kink instability in Z pinches has been studied numerically with a linearized ideal MHD model to reveal that a sheared axial flow stabilizes the kink mode when the shear exceeds a threshold. The sheared flow stabilizing effect is investigated with the flow-through Z pinch experiment, ZaP. An azimuthal array of surface mounted magnetic probes located at the midplane of the 50 cm long pinch plasma measures the fluctuation levels of the azimuthal modes m=1, 2, and 3. After pinch formation a quiescent period is found where the mode activity is reduced to a few percent of the average field. Optical images from a fast framing camera and a HeNe interferometer also indicate a stable pinch plasma during this time. Doppler shift measurements of a C-III line correspond to an axial flow velocity of 9.6x10 4 m/s internal to the pinch. During the time when the axial plasma flow is high, the plasma experiences a quiescent period which lasts approximately 800 exponential growth times predicted by linear theory for a static plasma. (author)

Diffusion-driven steady states of the Z-pinch

International Nuclear Information System (INIS)

Lehnert, B.

1988-01-01

Steady states of a Z-pinch where no electric field is imposed along the pinch axis by external means are investigated. In this case, diffusion-driven states become possible when imposed volume sources of particles and heat drive a radial diffusion velocity that, in its turn, generates the electric plasma current. The particle sources can be from pellet injection or a neutral gas blanket, and the heat sources provided by thermonuclear reactions or auxiliary heating. The present analysis and associated kinetic considerations indicate that steady diffusion-driven operation should become possible for certain classes of plasma profiles, without running into singularity problems at the pinch axis. Such operation leads to higher axial currents in a Z-pinch without an axial magnetic field than in a tokamaklike case under similar plasma conditions. The technical difficulty in realizing a volume distribution of particle sinks introduces certain constraints on the plasma and current profiles. This fact has to be taken into account in a stability analysis. Neoclassical or anomalous diffusion will increase the diffusion velocity of the plasma but is not expected to affect the main physical features of the present results

Flow effects on the stability of z-pinches

International Nuclear Information System (INIS)

Shumlak, U.; Hartman, C.W.

1996-01-01

The effect of an axial flow on the m = 1 kink instability in z-pinches is studied numerically by reducing the linearized ideal MHD equations to a one-dimensional eigenvalue equation for the radial displacement. The derivation of the displacement equation for equilibria with axial flows will be presented. A diffuse z-pinch equilibrium is chosen that is made marginally stable to the m = 0 sausage mode by tailoring the pressure profile. The principle result reveals that a sheared axial flow does stabilize the kink mode when the shear exceeds a threshold value. Additionally, the m = 0 sausage mode is driven from marginal stability into the stable regime which suggests that the equilibrium pressure profile control can be relaxed. Fast z-pinches such as liner implosions are plagued by the Rayleigh-Taylor instability which destroys the liner and disrupts the current path before the liner arrives on axis. A sheared axial flow in a liner may quench the Rayleigh-Taylor instability in the same way that it quenches MHD instabilities in a diffuse z-pinch. Simulation results will be presented showing the effect of a sheared axial flow on the Rayleigh-Taylor instability in a fast liner implosion

Developments of sausages in a z-pinch with short-wave perturbation of a boundary

International Nuclear Information System (INIS)

Vikhrev, V.V.; Ivanov, V.V.; Rozanova, G.A.

1989-01-01

A numeric simulation of sausage evolution in z-pinch during short-wave excitation of the boundary of plasma column pinch is carried out. The simulation has shown that due to nonlinear development of sausages in a pinch plasma colomn the cavities filled with a magnetic field in a rarefied pinch plasma are formed. Simultaneously compact column of tense plasma whose temperature is much higher than the average temperature of pinch plasma column are formed on the pinch axis. In the region of inlet in the cavity plasma is radially directed due to ponderomotoric force 1/2 x jB up to velocities greatly increasing the thermal velocity of ions in a plasma column

Mechanism of neutron generation in Z-pinches

International Nuclear Information System (INIS)

Vikhrev, V.V.

1986-01-01

The review of experimental and theoretical investigations in a mechanism of neutron generation in Z-pinches is presented. Special attention is paid to the thermonuclear mechanism of neutron generation occuring due to the formation of high-temperature plasma regions in Z-pinch sausage-type instabilities. This mechanism is shown to be predominant in charges with the neutron yield more than 10 9 per a charge. Experimental data, which are considered to be contradicting to thermonuclear nature of neutron radiation, are explained

Seeded perturbations in wire array Z-Pinches

International Nuclear Information System (INIS)

Robinson, Allen Conrad; Fedin, Dmitry; Kantsyrev, Victor Leonidovich; Wunsch, Scott Edward; Oliver, Bryan Velten; Lebedev, Sergey V.; Coverdale, Christine Anne; Ouart, Nicholas D.; LePell, Paul David; Safronova, Alla S.; Shrestha, I.; McKenney, John Lee; Ampleford, David J.; Rapley, J.; Bott, S.C.; Palmer, J.B.A.; Sotnikov, Vladimir Isaakovich; Bland, Simon Nicholas; Ivanov, Vladimir V.; Chittenden, Jeremy Paul; Jones, B.; Garasi, Christopher Joseph; Hall, Gareth Neville; Yilmaz, M. Faith; Mehlhorn, Thomas Alan; Deeney, Christopher; Pokala, S.; Nalajala, V.

2005-01-01

Controlled seeding of perturbations is employed to study the evolution of wire array z-pinch implosion instabilities which strongly impact x-ray production when the 3D plasma stagnates on axis. Wires modulated in radius exhibit locally enhanced magnetic field and imploding bubble formation at discontinuities in wire radius due to the perturbed current path. Wires coated with localized spectroscopic dopants are used to track turbulent material flow. Experiments and MHD modeling offer insight into the behavior of z-pinch instabilities.

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

International Nuclear Information System (INIS)

Hamann, F.

2003-12-01

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

Experimental study of the 'NOVA' Z-pinch equipment working as vacuum-gap

International Nuclear Information System (INIS)

Acuna, H.; Bernal, L.; Cortazar, D.; Iglesias, G.; Pouzo, J.

1990-01-01

The Z-pinch device 'NOVA' (2 kjoule, 10 kV, 250 kA) is operated as a vacuum gap. The plasma is generated in high vacuum (10 -5 mb) by the material let loose from the copper electrodes. Many strong compressions (micro pinches) are produced in the pinch column over the first quarter of the current period. This is detected by the observable pulses in the dI/dt signal. Hard X-rays generated in coincidence with the micro pinches are detected using a scintillator-photomultiplier system. This work studies the plasma evolution, by taking pictures of the pinch with obturation times of about 15 ns, temporally correlated with the dI/dt signal. Instabilities of types m=0 and m=1 are observed. (Author). 3 refs., 6 figs

The effects of shoulder load and pinch force on electromyographic activity and blood flow in the forearm during a pinch task

DEFF Research Database (Denmark)

Visser, Bart; Kofoed Nielsen, Pernille; de Kraker, Heleen

2006-01-01

loaded with 4.95 kg each) were combined with intermittent pinch forces at 0, 10 and 25% of the maximum voluntary contraction (MVC). Blood flow to the forearm was measured with Doppler ultrasound. Myoelectric activity of the forearm and neck-shoulder muscles was recorded to check for the workload levels....... Across all levels of shoulder load, blood flow increased significantly with increasing pinch force (21% at 10% MVC and by 44% at 25% MVC). Blood flow was significantly affected by shoulder load, with the lowest blood flow at the highest shoulder load. Interactions of pinch force and shoulder load were....... The results of this study indicate that shoulder load might influence blood flow to the forearm....

Spatially and temporally resolved EUV emissions from SATURN z-pinches

International Nuclear Information System (INIS)

Nash, T.J.; Breeze, S.; Mock, R.; Jobe, D.

1995-01-01

EUV emissions can be used to measure several z-pinch parameters. The authors have measured implosion velocity from Doppler splitting of lines and estimated electron temperature during run-in from the mean ionization state of line emissions. In an argon pinch they measure an electron temperature of 100 eV before stagnation. To date Doppler split lines have measured implosion velocities less than 40 cm/microsecond. They are presently attempting to measure magnetic field or load current from Zeeman splitting and it may be possible to measure electron density from a Stark-broadened line. Opacity and ion thermal broadening may also contribute to line width information. The spectrometer utilizes a variable line space grating to give a flat focal field. Spectral resolution with a 60 micron detector resolution is up to 3,000 and generally increases with wavelength. This is sufficient to detect several plasma line broadening mechanisms. The spectrometer may detect lines above 100 angstrom and below 1,400 angstrom. Spectral range across a microchannel plate stripline detector decreases with increasing wavelength setting. The authors may gate two striplines with 1 to 12 nsec gates at any time during the pinch discharge. Each stripline spatially images the pinch diameter perpendicular to the direction of dispersion. Spatial resolution in the pinch diameter is 1 mm. Spatial acquisition along the z axis is also 1 mm. Data are presented from argon, krypton, and aluminum z-pinch discharges on the SATURN accelerator

PBFA Z: A 20-MA z-pinch driver for plasma radiation sources

International Nuclear Information System (INIS)

Spielman, R.B.; Breeze, S.F.; Deeney, C.

1996-01-01

Sandia National Laboratories is completing a major modification to the PBFA-II facility. PBFA Z will be a z-pinch driver capable of delivering up to 20 MA to a z-pinch load. It optimizes the electrical coupling to the implosion energy of z pinches at implosion velocities of ∼ 40 cm/μs. Design constraints resulted in an accelerator with a 0.12-Ω impedance, a 10.25-nH inductance, and a 120-ns pulse width. The design required new water transmission lines, insulator stack, and vacuum power feeds. Current is delivered to the z-pinch load through four, self-magnetically-insulated vacuum transmission lines and a double post-hole convolute. A variety of design codes are used to model the power flow. These predict a peak current of 20 MA to a z-pinch load having a 2-cm length, a 2-cm radius, and a 15--mg mass, coupling 1.5 MJ into kinetic energy. We present 2-D Rad-Hydro calculations showing MJ x-ray outputs from tungsten wire-array z pinches

Dynamical analysis of surface-insulated planar wire array Z-pinches

Science.gov (United States)

Li, Yang; Sheng, Liang; Hei, Dongwei; Li, Xingwen; Zhang, Jinhai; Li, Mo; Qiu, Aici

2018-05-01

The ablation and implosion dynamics of planar wire array Z-pinches with and without surface insulation are compared and discussed in this paper. This paper first presents a phenomenological model named the ablation and cascade snowplow implosion (ACSI) model, which accounts for the ablation and implosion phases of a planar wire array Z-pinch in a single simulation. The comparison between experimental data and simulation results shows that the ACSI model could give a fairly good description about the dynamical characteristics of planar wire array Z-pinches. Surface insulation introduces notable differences in the ablation phase of planar wire array Z-pinches. The ablation phase is divided into two stages: insulation layer ablation and tungsten wire ablation. The two-stage ablation process of insulated wires is simulated in the ACSI model by updating the formulas describing the ablation process.

Magnetostatic Analysis of a Pinch Mode Magnetorheological Valve

Directory of Open Access Journals (Sweden)

Gołdasz Janusz

2017-09-01

Full Text Available The study deals with the pinch mode of magnetorheological (MR fluids’ operation and its application in MR valves. By applying the principle in MR valves a highly non-uniform magnetic field can be generated in flow channels in such a way to solidify the portion of the material that is the nearest to the flow channel’s walls. This is in contrary to well-known MR flow mode valves. The authors investigate a basic pinch mode valve in several fundamental configurations, and then examine their magnetic circuits through magnetostatic finite-element (FE analysis. Flux density contour maps are revealed and basic performance figures calculated and analysed. The FE analysis results yield confidence in that the performance of MR pinch mode devices can be effectively controlled through electromagnetic means.

Direction of Impurity Pinch and Auxiliary Heating in Tokamak Plasmas

International Nuclear Information System (INIS)

Angioni, C.; Peeters, A.G.

2006-01-01

A mechanism of particle pinch for trace impurities in tokamak plasmas, arising from the effect of parallel velocity fluctuations in the presence of a turbulent electrostatic potential, is identified analytically by means of a reduced fluid model and verified numerically with a gyrokinetic code for the first time. The direction of such a pinch reverses as a function of the direction of rotation of the turbulence in agreement with the impurity pinch reversal observed in some experiments when moving from dominant auxiliary ion heating to dominant auxiliary electron heating

Torus C-I field reversed theta-pinch at UNICAMP

International Nuclear Information System (INIS)

Machida, M.; Collares, M.P.; Honda, R.Y.; Sakanaka, P.H.; Scheid, V.H.B.

1984-01-01

The influence of multipole fields (octopole and quadrupole) on supressing the n=2 rotational instability, field reconnection, particle loss effects is studied, and the viability of transforming the theta-pinch from Campinas, Brazil (100Kv, 55Kj) to the field reversed theta-pinch with plasma translation program is analyzed. (E.G.) [pt

Preliminary study of Rayleigh-Taylor instability in wire-array Z-pinch

International Nuclear Information System (INIS)

He Kaihui; Feng Kaiming; Li Qiang; Gao Chunming

2000-01-01

It is important to research into the MHD Rayleigh-Taylor instability developed in Z-pinch implosion. A snowplough model of the single wire Z-pinch is presented. The perturbation amplitude of Rayleigh-Taylor instability in the wire-array Z-pinch is analyzed quantitatively. Sheared axial flow is put forward to mitigate and reduce the Rayleigh-Taylor instability. And other approaches used to mitigate MHD instability in such a super-fast process are explored

Metal Wire-array Load for Z-pinch Used as X-ray Source

Institute of Scientific and Technical Information of China (English)

1999-01-01

<正> The inertial confinement fusion （ICF） has evident minatory applications becasuse ICF ignites the fusion fuel with high energy media. As a method of ICF, Z-pinch has obtained evidently increased X-ray power PX-ray and energy EX-ray. The scientists have noticed this promising achievement. The Z-accelerator which is an operating Z-pinch device in Sandia national laboratory （SNL） in USA achieved 290 TW Px-ray in 1997 and the energy and defense departments of USA will finance SNL for a larger Z-pinch device. The early Z-pinch aimed to obtain high tempera

Radiative collapse of a Bennett-relaxed z-pinch

International Nuclear Information System (INIS)

Turner, L.

1989-01-01

The global evolution of a z-pinch has been studied with the assumption of a relaxed state consisting of ions and electrons, each in a rigidly drifting isothermal Maxwellian distribution. This speculative approach has the pragmatic feature of possessing phenomenologically useful global parameters such as drift velocity and temperature that vary in accordance with global physical quantities such as energy and entropy. The plasma gains energy from a time-dependent electric field by means of Poynting's vector. Coulomb collisions between electrons and ions is calculated with a Fokker-Planck treatment analogous to that used by Dreicer to calculate runaways. For a variety of initial conditions and time-independent applied electric fields, the pinch evolution always culminates in a time-independent (attractor) state whose current is the Pease-Braginskii current and whose final radius is proportional to (line density)/sup 3/4//(electric field)/sup 1/2/. Before the final state is attained, the pinch may bounce toward and away from a highly collapsed state. For the case of a Bennett pinch, the classical limit of the resistivity is attained when the line density is much greater than 4πm/sub e//e 2 μ/sub o/; i.e., 3.55 /times/ 10 14 m/sup /minus/1/. 6 refs., 2 figs

Deuterated fibre Z-pinch on the S-300 generator

NARCIS (Netherlands)

Klir, D.; Kravarik, J.; Kubes, P.; Bakshaev, Yu L.; Blinov, P. I.; Chernenko, A. S.; Danko, S. A.; Korolev, V. D.; Ustroev, G. I.; Ivanov, M. I.; Cai, Hongchun

2006-01-01

Dense Z-pinch experiments were carried out on the S-300 generator (3.5 MA, 100 ns, 0.15 Omega) at the Kurchatov Institute in Moscow. The experiments were performed at a peak current of 2 MA with a rise time of about 100 ns. The Z-pinch was formed from a deuterated polyethylene fibre of 100 mu m

Plasma-erosion-enhanced neutron emission in fiber-generated dense Z-pinches

International Nuclear Information System (INIS)

Mosher, D.; Colombant, D.

1990-01-01

Experiments in which dense z-pinches are created from high-current discharges through frozen deuterium fibers have reported neutron yields far in excess of those expected from thermal processes. A simple analysis based on pinch collapse due to the sausage instability has successfully predicted the relative variation of neutron yield with discharge current, but model assumptions precluded prediction of absolute values of the yield. A pinch-collapse model derived from a 2-dimensional, nonlinear treatment of the sausage instability, combined with space-charged-limited (SCL) ion orbital dynamic for the vacuum region above the pinches and between the expanding flares, leads to neutron yields four or more orders-of-magnitude below experimental values. Here, the same pinch-collapse model is used in conjunction with a low-density plasma background above the collapsing pinches. Ions are accelerated across the space-charge sheath separating the background plasma from the flares, which electron emission from the flares is strongly insulated by the z-discharge magnetic field. The sheath gap increases in time, i.e., the background plasma erodes, at a rate determined by its density and the SCL ion current density which, in turn, depends on the z-discharge dynamics and the associated induced electromagnetic fields. A model incorporating the above processes is used to determine the accelerated ion energy spectrum and associated neutron yield as functions of the discharge, instability, and background parameters

PBFA Z: A 60-TW/5-MJ Z-pinch driver

International Nuclear Information System (INIS)

Spielman, R.B.; Deeney, C.; Chandler, G.A.; Douglas, M.R.; Fehl, D.L.; Matzen, M.K.; McDaniel, D.H.; Nash, T.J.; Porter, J.L.; Sanford, T.W.; Seamen, J.F.; Stygar, W.A.; Struve, K.W.; Breeze, S.P.; McGurn, J.S.; Torres, J.A.; Zagar, D.M.; Gilliland, T.L.; Jobe, D.O.; McKenney, J.L.; Mock, R.C.; Vargas, M.; Wagoner, T.; Peterson, D.L.

1997-01-01

PBFA Z, a new 60-TW/5-MJ electrical accelerator located at Sandia National Laboratories, is now the world's most powerful z-pinch driver. PBFA Z stores 11.4 MJ in its 36 Marx generators, couples 5 MJ into a 60-TW/105-ns FWHM pulse to the 120-mΩ water transmission lines, and delivers 3.0 MJ and 50 TW of electrical energy to the z-pinch load. Depending on load parameters, we attain peak load currents of 16-20 MA with a current rise time of ∼105ns with wire-array z-pinch loads. We have extended the x-ray performance of tungsten wire-array z pinches from earlier Saturn experiments. Using a 2-cm-radius, 2-cm-long tungsten wire array with 240, 7.5-μm diameter wires (4.1-mg mass), we achieved an x-ray power of 210 TW and an x-ray energy of 1.9 MJ. Preliminary spectral measurements suggest a mostly optically-thick, Planckian-like radiator below 1000 eV. Data indicate ∼100kJ of x rays radiated above 1000 eV. An intense z-pinch x-ray source with an overall coupling efficiency greater than 15% has been demonstrated. copyright 1997 American Institute of Physics

Self-pinched transport of intense ion beams

International Nuclear Information System (INIS)

Ottinger, P.F.; Neri, J.M.; Stephanakis, S.J.

1999-01-01

Electron beams with substantial net currents have been routinely propagated in the self-pinched mode for the past two decades. However, as the physics of gas breakdown and beam neutralization is different for ion beams, previous predictions indicated insufficient net current for pinching so that ion beam self-pinched transport (SPT) was assumed impossible. Nevertheless, recent numerical simulations using the IPROP code have suggested that ion SPT is possible. These results have prompted initial experiments to investigate SPT of ion beams. A 100-kA, 1.2-MeV, 3-cm-radius proton beam, generated on the Gamble II pulsed-power accelerator at NRL, has been injected into helium in the 30- to 250-mTorr regime to study this phenomenon. Evidence of self-pinched ion beam transport was observed in the 35- to 80-mTorr SPT pressure window predicted by IPROP. Measured signals from a time- and space-resolved scattered proton diagnostic and a time-integrated Li(Cu) nuclear activation diagnostic, both of which measure protons striking a 10-cm diameter target 50 cm into the transport region, are significantly larger in this pressure window than expected for ballistic transport. These results are consistent with significant self-magnetic fields and self-pinching of the ion beam. On the other hand, time-integrated signals from these same two diagnostics are consistent with ballistic transport at pressures above and below the SPT window. Interferometric electron line-density measurements, acquired during beam injection into the helium gas, show insignificant ionization below 35 mTorr, a rapidly rising ionization fraction with pressure in the SPT window, and a plateau in ionization fraction at about 2% for pressures above 80 mTorr. These and other results are consistent with the physical picture for SPT. IPROP simulations, which closely model the Gamble II experimental conditions, produce results that are in qualitative agreement with the experimental results. The advantages of SPT for

Plasma dynamics in a staged pinch device

International Nuclear Information System (INIS)

Khattak, N.A.D.; Ahmed, Z.; Mirza, A.M.; Murtaza, G.

1998-01-01

Plasma parameters in fiber initiated fast and dense theta-pinch plasma driven by an annular finite-thickness gas-puff Z-pinch are studied. The imploding gas-puff Z-pinch plasma traps an axial magnetic field B/sub z/, compressing it to large values (of the order of several megagauss) in an extremely short time. The rapidly changing magnetic flux of this field induces an azimuthal current on the surface of the coaxially placed fiber, with a rise time an order of magnitude shorter than the applied Z-pinch current. The shorter rise time of the current stabilizes the pinch against sausage mode of MHD instabilities. Our numerical results demonstrate that for a relatively thick gas-puff layer, the compression occurs before the current saturates. At the peak compression the fuel densities of the order of 10/sup 25/ cm/sup -3/ and temperature above 10 keV can be achieved on a time scale of 0.1 nanoseconds, yielding the Lawson Criterion parameters n tau is approximately equal to 10/sup 14/ sec cm/sup -3/ for D-T fuel. The snow-plow effect incorporated in our model exercise a strong influence on the onset and growth rate of sausage and Rayleigh-Taylor (R-T) modes of instabilities. Imposing a rotational velocity on the outer thin gas-puff plasma can control the Rayleigh-Taylor instability. Numerical results indicate that the choice of the spin velocity is critical. Large values of the spin velocity, though provide stabilization against the R-T instability at the final stage of compression, however, it adversely reduce the plasma parameters so essential to achieve controlled fusion. Our analysis, therefore, suggests that a judicious choice of the spin velocity is necessary to obtain the desired temperature and density, especially when we seed D-T fiber plasma with a small fraction of high-Z Kr impurity to initiate the radiative collapse. (author)

Recent developments in linear theta-pinch research: experiment and theory

International Nuclear Information System (INIS)

McKenna, K.F.; Bartsch, R.R.; Commisso, R.J.

1978-01-01

High energy plasmas offusion interest can be generated in linear theta pinches. However, end losses present a fundamental limitation on the plasma containment time. This paper discusses recent progress in end-loss and end-stoppering experiments and in the theoretical understanding of linear theta-pinch physics

UV Laser Diagnostics of the 1-MA Z-pinch Plasmas

International Nuclear Information System (INIS)

Altemara, S. D.; Ivanov, V. V.; Astanovitskiy, A. L.; Haboub, A.

2009-01-01

The 532 nm laser diagnostic set at the Zebra generator shows the details of the ablation and stagnation phases in cylindrical, planar, and star-like wire arrays but it cannot show the structure of the stagnated z-pinch and the implosion in small diameter loads, 1-3 mm in diameter. The absorption increment and the refraction angle of the 532 nm laser, when passing through the plasma, are too great to obtain quality images. An ultraviolet probing beam at the wavelength of 266 nm was developed to study small-diameter loads and to investigate the structure of the 1-MA z-pinch. The UV radiation has a much smaller absorption increment and refraction angles in plasmas than the 532 nm light and allows for better imaging of the z-pinch plasmas. Estimates showed that UV probing would be able to probe the high-density z-pinch plasma in experiments on the Zebra generator, and the early results of UV probing on the Zebra generator have shown promise.

Mechanism of hot spots formation in magnetic Z-pinch

Energy Technology Data Exchange (ETDEWEB)

Kubes, P; Kravarik, J [Ceske Vysoke Uceni Technicke, Prague (Czech Republic). Fakulta Elektrotechnicka; Kolacek, K; Krejci, A [Akademie Ved Ceske Republiky, Prague (Czech Republic). Ustav Fyziky Plazmatu; Paduch, M; Tomaszewski, K [Inst. of Plasma Physics and Laser Microfusion, Warsaw (Poland)

1997-12-31

The evolution of neon implosion of low energy discharge (4 kJ, 40 kV, 150 kA, 1.1 {mu}s) was studied using X-ray, schlieren and high speed electrooptical visible gated Quadro camera diagnostics. The geometry, the helical structure of pinched column, two steps of pinching and X-ray emission were studied. The diameters, electron density and temperature of the hot spots were determined. The hypothesis of axial component of magnetic field generation, of helical shape of magnetic and electric field lines, of the possibility of the release of magnetic energy and of the acceleration of the keV electrons and ions due to voltage induction during the second pinching of the column are discussed. (author). 3 figs., 5 refs.

X-Pinch soft x-ray source for microlithography

International Nuclear Information System (INIS)

Glidden, S.C.; Hammer, D.A.; Kalantar, D.H.; Qi, N.

1993-01-01

The x-pinch soft x-ray source is described for application in submicron resolution lithography. Experiments have been performed to characterize the radiation emitted from magnesium wire x-pinch plasmas using an 80 ns, ≤500 kA pulse. Yields of 14.2 J averaged over three independent calibrated diagnostics at 445 kA have been measured in magnesium K-shell radiation (predominantly 8.4 angstrom to 9.4 angstrom or 1.5 keV to 1.3 keV) from a submillimeter source, with as little as 5-10% of the yield below the 6.74 angstrom silicon absorption edge. A new ≤700 kA, 100 ns pulser being used for x-pinch physics experiments is described. The design of a 40 pulse per second pulsed power system and wire loading mechanism for exposing a resist in 1 second at a distance 40 cm is presented

Putting the pinch on reactors

International Nuclear Information System (INIS)

Glavic, P.; Kravanja, Z.; Homsak, M.

1990-01-01

Pinch technology has proven to be a powerful tool for designing new processes and retrofitting old ones. But, until recently, it was thought to pertain only to heat exchanger networks, separators and power devices (such as heat engines and heat pumps). Regarded as process background, reactors have been left out of heat integrations. Their structure, however, can be changed and, within limits, their parameters modified to better exploit energy. In a pinch-designed plant, heat is transferred between the hot and cold process streams so efficiently that the plant's utility requirements (heat sources and sinks) are minimal. The design procedure is discussed. It involves two steps: finding a nearly optimal process structure by means of an analysis of process-temperature-vs.- enthalpy diagrams, and then optimizing the structure by means of grid diagrams or a computerized procedure

Pinch modes in the SPEED2 plasma focus

International Nuclear Information System (INIS)

Kies, W.; Decker, G.; Berntien, U.; Glushkov, D.A.; Sidelnikov, Yu.V.; Koshelev, K.N.; Simanovskij, D.M.; Bobashev, S.V.

2001-01-01

Deuterium discharges in the SPEED2 plasma focus (80 kJ, 200 kV, 2 MA, 400 ns) have been found unexpectedly stable within the operational regime as a neutron source. Only at higher filling pressures (above 6 mbar) sometimes m=0 instabilities appeared in the pinch column, especially in discharges of lower efficiency (moderate dynamics and neutron yield). Enhancing the electromagnetic radiation by doping these discharges with heavy gases (e.g. neon, argon) distinctly two pinch modes are produced, the micropinch mode (MPM) or the stable column mode (SCM), with a transition regime where the initial SCM is followed by the MPM. Micropinches are local radiative collapses initiated by m=0 instabilities of low-energy-density pinch plasmas. These instabilities and the successive micropinches can be suppressed by kinetic deuterons produced during dynamical compression of high-energy-density deuterium plasma sheaths. Depending on the relaxation of this fast deuteron component the pinch column can be stabilized for several tens of nanoseconds. While the short-lived (appr.1 ns) micropinches erratically appear as point-like successive flashes along the pinch axis with temperatures about 1 keV and about solid density the reproducible SCM, optimized with respect to the compression ratio, forms a powerful linear radiation source of temperatures and densities similar to the MPM. The SCM needs powerful (fast) drivers in order to use the kinetic ion stabilization, but not necessarily MA currents as available from the SPEED2 driver. This opens the possibility to establish the SCM also in compact experiments like SPEED3 (8 kJ, 80 kV, 0.8 MA, 300 ns) or even SPEED4 (2 kJ, 40 kV 250 kA, 300 ns). (author)

Stage theta pinch experiments

International Nuclear Information System (INIS)

Linford, R.K.; Downing, J.N.; Gribble, R.F.; Jacobson, A.R.; Platts, D.A.; Thomas, K.S.

1975-01-01

The Staged Theta Pinch program is designed to study the technological and physics problems associated with producing fat plasmas and separating the implosion heating from the adiabatic compression. Several methods of implosion heating are discussed. Circuit diagrams and theoretical magnetic field behavior are described for the STP and resonant heating experiments. (MOW)

30 CFR 75.1731 - Maintenance of belt conveyors and belt conveyor entries.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Maintenance of belt conveyors and belt conveyor....1731 Maintenance of belt conveyors and belt conveyor entries. (a) Damaged rollers, or other damaged belt conveyor components, which pose a fire hazard must be immediately repaired or replaced. All other...

Electron-Cloud Pinch Dynamics in Presence of Lattice Magnet Fields

CERN Document Server

Franchetti, G

2011-01-01

The pinch of the electron cloud due to a passing proton bunch was extensively studied in a field free region and in a dipolar magnetic field. For the latter study, a strong field approximation helped to formulate the equations of motion and to understand the complex electron pinch dynamics, which exhibited some similarities with the field-free situation. Here we extend the analysis to the case of electron pinch in quadrupoles and in sextupoles. We discuss the limits of validity for the strong field approximation and we evaluate the relative magnitude of the peak tune shift along the bunch expected for the different fields.

Kinetic theory of the sausage instability of a z-pinch

International Nuclear Information System (INIS)

Isichenko, M.B.; Kulyabin, K.L.; Yan'kov, V.V.

1989-01-01

A linear problem of z-pinch sausage development is considered taking into account the influence of kinetic effects for ideal scanning current. Plasma electrons are considered to be cold and ions - collisionless. It is also supposed that the magnetic field inside a pinch doesn't affect the motion of ions, which are reflected like in a mirror from a jump of an electric potential arising on the plasma boundary. In case of long-wave perturbations ka >1 the acount of kinetics leads to considerable decrease of the increment [(ka) 1/2 times] in comparison with the hydrodynamic description, that permits to explain the increased instability of z-pinches observed in experiments

Plasma channel and Z-pinch dynamics for heavy ion transport

Energy Technology Data Exchange (ETDEWEB)

Ponce-Marquez, David [Univ. of California, Berkeley, CA (United States)

2002-01-01

A self stabilized, free standing, z-pinch plasma channel has been proposed to deliver the high intensity heavy ion beam from the end of a driver to the fuel target in a heavy ion inertial fusion power plant. The z-pinch relaxes emittance and energy spread requirements requiring a lower cost driver. A z-pinch transport would reduce the number of beam entry port holes to the target chamber from over a hundred to four as compared to neutralized ballistic focusing thus reducing the driver hardware exposure to neutron flux. Experiments where a double pulse discharge technique is used, z-pinch plasma channels with enhanced stability are achieved. Typical parameters are 7 kV pre-pulse discharge and 30 kV main bank discharge with 50 kA of channel current in a 7 torr background gas atmosphere. This work is an experimental study of these plasma channels examining the relevant physics necessary to understand and model such plasmas. Laser diagnostics measured the dynamical properties of neutrals and plasma. Schlieren and phase contrast techniques probe the pre-pulse gas dynamics and infrared interferometry and faraday effect polarimetry are used on the z-pinch to study its electron density and current distribution. Stability and repeatability of the z-pinch depend on the initial conditions set by the pre-pulse. Results show that the z-pinch channel is wall stabilized by an on-axis gas density depression created by the pre-pulse through hydrodynamic expansion where the ratio of the initial gas density to the final gas density is > 10/1. The low on-axis density favors avalanching along the desired path for the main bank discharge. Pinch time is around 2 s from the main bank discharge initiation with a FWHM of ~ 2 cm. Results also show that typical main bank discharge plasma densities reach 10¹⁷ cm^-3 peak on axis for a 30 kV, 7 torr gas nitrogen discharge. Current rise time is limited by the circuit-channel inductance with the highest contribution to the

Experiments on the ZT-S reversed-field pinch, August--December 1978

International Nuclear Information System (INIS)

Jacobson, A.R.

1979-06-01

During the latter half of 1978 the ZT-S reversed-field pinch was used to explore the utility of pitch-programming techniques in setting up stable diffuse pinch profiles. Several experimental observations relating to this goal are presented

Lap belts and three-point belts.

NARCIS (Netherlands)

Kampen, L.T.B. van & Edelman, A.

1975-01-01

Results of the swov-accident investigation prove that if there are any differences in the effectiveness of lap belts and three-point belts, these are so small that they cannot form a basis for giving preference to one type over the other. Furthermore, in spite of the results of this investigation

Energy transfer efficiency measurements in a theta-pinch

International Nuclear Information System (INIS)

Cavalcanti, G.H.; Luna, F.R.T.; Trigueiros, A.G.

1993-01-01

An increase in energy transfer efficiency of the capacitor bank to the plasma was obtained when the electrical system of a theta-pinch was changed so that the ratio of total inductance to coil inductance was switched of 1/6 to 1/2. A further increase about 20% was obtained for 16/1 ratio. The measurements were made through the current discharge decay, and the spectral analysis of the emitted light from theta-pinch shows a correspondent efficiency increase. (author)

Simulation of engine auxiliary drive V-belt slip motion. Part 1. Development of belt slip model; Engine hoki V belt slip kyodo no simulation. 1. Belt slip model no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Kurisu, T [Mazda Motor Corp., Hiroshima (Japan)

1997-10-01

V-belts are widely used for driving auxiliary components of an engine. Inadequet design of such belt system sometimes results in troubles such as belt squeak, side rubber separation and/or bottom rubber crack. However, there has been no design tools which can predict belt slip quantitatively. The author developed a motion simulation program of Auxiliary Drive V-Belt System considering belt slip. The program showed good prediction accuracy for belt slip motion. This paper describes the simulation model. 1 ref., 12 figs.

Developing models for simulation of pinched-beam dynamics in heavy ion fusion. Revision 1

International Nuclear Information System (INIS)

Boyd, J.K.; Mark, J.W.K.; Sharp, W.M.; Yu, S.S.

1984-01-01

For heavy-ion fusion energy applications, Mark and Yu have derived hydrodynamic models for numerical simulation of energetic pinched-beams including self-pinches and external-current pinches. These pinched-beams are applicable to beam propagation in fusion chambers and to the US High Temperature Experiment. The closure of the Mark-Yu model is obtained with adiabatic assumptions mathematically analogous to those of Chew, Goldberger, and Low for MHD. Features of this hydrodynamic beam model are compared with a kinetic treatment

Producing High-Performance, Stable, Sheared-Flow Z-Pinches in the FuZE project

Science.gov (United States)

Golingo, R. P.; Shumlak, U.,; Nelson, B. A.; Claveau, E. L.; Forbes, E. G.; Stepanov, A. D.; Weber, T. R.; Zhang, Y.; McLean, H. S.; Tummel, K. K.; Higginson, D. P.; Schmidt, A. E.; University of Washington (UW) Collaboration; Lawrence Livermore National Laboratory (LLNL) Collaboration

2017-10-01

The Fusion Z-Pinch Experiment (FuZE) has made significant strides towards generating high-performance, stable Z-pinch plasmas with goals of ne = 1018 cm-3 and T =1 keV. The Z-pinch plasmas are stabilized with a sheared axial flow that is driven by a coaxial accelerator. The new FuZE device has been constructed and reproduces the major scientific achievements the ZaP project at the University of Washington; ne = 1016 cm-3,T = 100 eV, r20 μs. These parameters are measured with an array of magnetic field probes, spectroscopy, and fast framing cameras. The plasma parameters are achieved using a small fraction of the maximum energy storage and gas injection capability of the FuZE device. Higher density, ne = 5×1017 cm-3, and temperature, T = 500 eV, Z-pinch plasmas are formed by increasing the pinch current. At the higher voltages and currents, the ionization rates in the accelerator increase. By modifying the neutral gas profile in the accelerator, the plasma flow from the accelerator is maintained, driving the flow shear. Formation and sustainment of the sheared-flow Z-pinch plasma will be discussed. Experimental data demonstrating high performance plasmas in a stable Z-pinches will be shown. This work is supported by an award from US ARPA-E.

Seat belt reminders.

NARCIS (Netherlands)

2008-01-01

Seat belts are an effective way of reducing the number or road deaths and severe road injuries in crashes. Seat belt reminders warn car drivers and passengers if the seat belt is not fastened. This can be done by a visual signal or an acoustic signal or by a combination of the two. Seat belt

Self-stabilized pinch (SSP) concept

International Nuclear Information System (INIS)

Sugisaki, Kiwamu; Hirano, Keiichi.

1985-01-01

Self-Stabilized pinch (SSP) consept is revealed. SSP providcs many attractive features for application to a fusion reactor. Design studies for high temperature plasma production are carried out. Use of adiabatic compression leads to a remarkable reduction of required power source. (author)

Gas-puff Z-pinch experiment on the LIMAY-I

International Nuclear Information System (INIS)

Takasugi, K.; Miyamoto, T.; Akiyama, H.; Shimomura, N.; Sato, M.; Tazima, T.

1989-01-01

A gas-puff z-pinch plasma has been produced on the pulsed power generator LIMAY-I at IPP Nagoya University. The stored energy of the generator is 13 kJ, and it generates 600 kV-70 ns-3 Ω power pulse. Ar or He gas is puffed from a hollow nozzle with 18 mm diameter, and a z-pinch plasma is produced by a discharge between 3 mm gap electrodes

Quasi-steady accelerator operation on the ZAP flow Z-pinch

Energy Technology Data Exchange (ETDEWEB)

Hughes, M. C., E-mail: mchugs@uw.edu; Shumlak, U., E-mail: mchugs@uw.edu; Golingo, R. P., E-mail: mchugs@uw.edu; Nelson, B. A., E-mail: mchugs@uw.edu; Ross, M. P., E-mail: mchugs@uw.edu [Aerospace and Energetics Research Program, University of Washington, Seattle, WA 98195 (United States)

2014-12-15

The ZaP Flow Z-Pinch Experiment utilizes sheared flows to stabilize an otherwise unstable equilibrium. The sheared flows are maintained by streaming high velocity plasma parallel to the pinch. Previous operations of the machine show depletion of the accelerator’s neutral gas supply late in the pulse leading to pinch instability. The current distribution in the accelerator exhibits characteristic modes during this operation, which is corroborated by interferometric signals. The decrease in density precipitates a loss of plasma quiescence in the pinch, which occurs on a timescale related to the flow velocity from the plasma source. To abate the depletion, the geometry of the accelerator is altered to increase the neutral gas supply. The design creates a standing deflagration front in the accelerator that persists for the pulse duration. The new operating mode is characterized by the same diagnostics as the previous mode. The lessons learned in the accelerator operations have been applied to the design of a new experiment, ZaP-HD. This work was supported by grants from the Department of Energy and the National Nuclear Security Administration.

Model of enhanced energy deposition in a Z-pinch plasma

International Nuclear Information System (INIS)

Velikovich, A. L.; Davis, J.; Thornhill, J. W.; Giuliani, J. L. Jr.; Rudakov, L. I.; Deeney, C.

2000-01-01

In numerous experiments, magnetic energy coupled to strongly radiating Z-pinch plasmas exceeds the thermalized kinetic energy, sometimes by a factor of 2-3. An analytical model describing this additional energy deposition based on the concept of macroscopic magnetohydrodynamic (MHD) turbulent pinch heating proposed by Rudakov and Sudan [Phys. Reports 283, 253 (1997)] is presented. The pinch plasma is modeled as a foam-like medium saturated with toroidal ''magnetic bubbles'' produced by the development of surface m=0 Rayleigh-Taylor and MHD instabilities. As the bubbles converge to the pinch axis, their magnetic energy is converted to thermal energy of the plasma through pdV work. Explicit formulas for the average dissipation rate of this process and the corresponding contribution to the resistance of the load, which compare favorably to the experimental data and simulation results, are presented. The possibility of using this enhanced (relative to Ohmic heating) dissipation mechanism to power novel plasma radiation sources and produce high K-shell yields using long current rise time machines is discussed. (c) 2000 American Institute of Physics

Steady state theta pinch concept for slow formation of FRC

International Nuclear Information System (INIS)

Hirano, K.

1987-05-01

A steady state high beta plasma flow through a channel along the magnetic field increasing downstream can be regarded as a ''steady state theta pinch'', because if we see the plasma riding on the flow we should observe very similar process taking place in a theta pinch. Anticipating to produce an FRC without using very high voltage technics such as the ones required in a conventional theta pinch, we have studied after the analogy a ''steady state reversed field theta pinch'' which is brought about by steady head-on collision of counter plasma streams along the channel as ejected from two identical co-axial plasma sources mounted at the both ends of the apparatus. The ideal Poisson and shock adiabatic flow models are employed for the analysis of the steady colliding process. It is demonstrated that an FRC involving large numbers of particles is produced only by the weak shock mode which is achieved in case energetic plasma flow is decelerated almost to be stagnated through Poisson adiabatic process before the streams are collided. (author)

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

International Nuclear Information System (INIS)

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

2000-01-01

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

Belt Aligning Revisited

Directory of Open Access Journals (Sweden)

Yurchenko Vadim

2017-01-01

parts of the conveyor, the sides of the belt wear intensively. This results in reducing the life of the belt. The reasons for this phenomenon are well investigated, but the difficulty lies in the fact that they all act simultaneously. The belt misalignment prevention can be carried out in two ways: by minimizing the effect of causes and by aligning the belt. The construction of aligning devices and errors encountered in practice are considered in this paper. Self-aligning roller supports rotational in plan view are recommended as a means of combating the belt misalignment.

PBFA Z: A 20-MA Z-pinch driver for plasma radiation sources

International Nuclear Information System (INIS)

Spielman, R.B.; Breeze, S.F.; Deeney, C.

1996-01-01

Sandia National Laboratories is completing a major modification to the PBFA-II facility. PBFA Z will be capable of delivering up to 20 MA to a z-pinch load. It optimizes the electrical coupling to the implosion energy of z pinches at implosion velocities of ∼ 40 cm/μs. Design constraints resulted in an accelerator with a 0.12-Ω impedance, a 10.25-nH inductance, and a 120-ns pulse width. The design required new water transmission lines, insulator stack, and vacuum power feeds. Current is delivered to the z-pinch load through four self-magnetically-insulated vacuum transmission lines and a double post-hole convolute. A variety of design codes are used to model the power flow. These predict a peak current of 20 MA to a z-pinch load having a 2-cm length, a 2-cm radius, and a 15-mg mass, coupling 1.5 MJ into kinetic energy. Calculations are presented showing MJ x-ray outputs from tungsten wire-array z pinches. (author). 4 figs., 14 refs

PBFA Z: A 20-MA Z-pinch driver for plasma radiation sources

Energy Technology Data Exchange (ETDEWEB)

Spielman, R B; Breeze, S F; Deeney, C [Sandia Labs., Albuquerque, NM (United States); and others

1997-12-31

Sandia National Laboratories is completing a major modification to the PBFA-II facility. PBFA Z will be capable of delivering up to 20 MA to a z-pinch load. It optimizes the electrical coupling to the implosion energy of z pinches at implosion velocities of {approx} 40 cm/{mu}s. Design constraints resulted in an accelerator with a 0.12-{Omega} impedance, a 10.25-nH inductance, and a 120-ns pulse width. The design required new water transmission lines, insulator stack, and vacuum power feeds. Current is delivered to the z-pinch load through four self-magnetically-insulated vacuum transmission lines and a double post-hole convolute. A variety of design codes are used to model the power flow. These predict a peak current of 20 MA to a z-pinch load having a 2-cm length, a 2-cm radius, and a 15-mg mass, coupling 1.5 MJ into kinetic energy. Calculations are presented showing MJ x-ray outputs from tungsten wire-array z pinches. (author). 4 figs., 14 refs.

Condition-Based Conveyor Belt Replacement Strategy in Lignite Mines with Random Belt Deterioration

Science.gov (United States)

Blazej, Ryszard; Jurdziak, Leszek

2017-12-01

In Polish lignite surface mines, condition-based belt replacement strategies are applied in order to assure profitable refurbishment of worn out belts performed by external firms specializing in belt maintenance. In two of three lignite mines, staff asses belt condition subjectively during visual inspections. Only one mine applies specialized diagnostic device (HRDS) allowing objective magnetic evaluation of belt core condition in order to choose the most profitable moment for the dismantling of worn out belt segments from conveyors and sending them to the maintenance firm which provides their refurbishment. This article describes the advantages of a new diagnostic device called DiagBelt. It was developed at the Faculty of Geoengineering, Mining and Geology, Wroclaw University of Science and Technology. Economic gains from its application are calculated for the lignite mine and for the belt maintenance firm, taking into account random life (durability) of new and reconditioned belts (after the 1st and the 2nd refurbishment). Recursive calculations for following years allow the estimation of the length and costs of replaced, reconditioned and purchased belts on an annual basis, while the use of the Monte Carlo method allows the estimation of their variability caused by random deterioration of belts. Savings are obtained due to better selection of moments (times) for the replacement of belt segments and die to the possibility to qualify worn out belts for refurbishment without the need to remove their covers. In effect, increased belt durability and lowered share of waste belts (which were not qualified for reconditioning) create savings which can quickly cover expenditures on new diagnostic tools and regular belt inspections in the mine.

''Turbulent Equipartition'' Theory of Toroidal Momentum Pinch

International Nuclear Information System (INIS)

Hahm, T.S.; Diamond, P.H.; Gurcan, O.D.; Rewaldt, G.

2008-01-01

The mode-independent part of magnetic curvature driven turbulent convective (TuroCo) pinch of the angular momentum density (Hahm et al., Phys. Plasmas 14,072302 (2007)) which was originally derived from the gyrokinetic equation, can be interpreted in terms of the turbulent equipartition (TEP) theory. It is shown that the previous results can be obtained from the local conservation of 'magnetically weighted angular momentum density', nm i U # parallel# R/B 2 , and its homogenization due to turbulent flows. It is also demonstrated that the magnetic curvature modification of the parallel acceleration in the nonlinear gyrokinetic equation in the laboratory frame, which was shown to be responsible for the TEP part of the TurCo pinch of angular momentum density in the previous work, is closely related to the Coriolis drift coupling to the perturbed electric field. In addition, the origin of the diffusive flux in the rotating frame is highlighted. Finally, it is illustrated that there should be a difference in scalings between the momentum pinch originated from inherently toroidal effects and that coming from other mechanisms which exist in a simpler geometry.

Liquid conductor model of instabilities in a pinched discharge

Energy Technology Data Exchange (ETDEWEB)

Dattnery, A; Lehnert, B [Dept. of Electronics, Royal Institute of Technology, Stockholm (Sweden); Lundquist, S [Swedish State Power Board (Sweden)

1958-07-01

The pinched gas discharge experiments seem to have been handicapped by the great speed with which the instability develops as well as by the light coming from impurities instead of the main body of pinched gas. In the present work a liquid conductor is used in order to study the structure of the instabilities. The study of a pinch was made with and without the axial magnetic field. In cases with a magnetic field, the currents and fields were chosen so as to give a longitudinal magnetic field equal to or three times the azimuthal field at the boundary of the mercury stream. The study of the results shows that in the case without an external magnetic field there is a similarity between the behavior of the pinch in a stream of mercury and in an ionized gas column. The stabilizing action of the surface tension is small and the instabilities develop easily. The case with an external magnetic field is more complicated. The magnetic lines of force are not frozen into the medium; they can 'escape' from the medium. In this case the magnetic field has no stabilizing effect. The influence of conducting walls around the mercury column will be studied in forthcoming experiments.

Simplified scaling model for the THETA-pinch

Science.gov (United States)

Ewing, K. J.; Thomson, D. B.

1982-02-01

A simple ID scaing model for the fast Theta pinch was developed and written as a code that would be flexible, inexpensive in computer time, and readily available for use with the Los Alamos explosive-driven high magnetic field program. The simplified model uses three successive separate stages: (1) a snowplow-like radial implosion, (2) an idealized resistive annihilation of reverse bias field, and (3) an adiabatic compression stage of a Beta = 1 plasma for which ideal pressure balance is assumed to hold. The code uses one adjustable fitting constant whose value was first determined by comparison with results from the Los Alamos Scylla III, Scyllacita, and Scylla IA Theta pinches.

Numerical investigations of Z-pinch plasma instabilities

International Nuclear Information System (INIS)

Duan Yaoyong; Guo Yonghui; Wang Wensheng; Qiu Aici

2004-01-01

A two-dimensional, radiation magneto-hydrodynamics model is applied to the simulation of Z-pinch plasma sausage instability. Different implosion mechanisms in the cases of the existence and the non-existence of instability are analyzed, and the effects of various initial density perturbation levels on the x-ray power and energy are investigated. Numerical results show that x-ray energy output is not susceptive to sausage instabilities in a certain extent but x-ray power versus time is evidently dependent on the instabilities. In addition, this paper also studies the effects of numerical treatment of extreme low density in Z-pinch simulations on numerical results

Linear Transformer Drivers for Z-pinch Based Propulsion

Science.gov (United States)

Adams, Robert; Seidler, William; Giddens, Patrick; Fabisinski, Leo; Cassibry, Jason

2017-01-01

The MSFC/UAH team has been developing of a novel power management and distribution system called a Linear Transformer Driver (LTD). LTD's hold the promise of dramatically reducing the required mass to drive a z-pinch by replacing the capacitor banks which constitute half the mass of the entire system. The MSFC?UAH tea, is developing this technology in hope of integrating it with the Pulsed Fission Fusion (PuFF) propulsion concept. High-Voltage pulsed power systems used for Z-Pinch experimentation have in the past largely been based on Marx Generators. Marx generators deliver the voltage and current required for the Z-Pinch, but suffer from two significant drawbacks when applied to a flight system: they are very massive, consisting of high-voltage capacitor banks insulated in oil-filled tanks and they do not lend themselves to rapid pulsing. The overall goal of Phase 2 is to demonstrate the construction of a higher voltage stack from a number of cavities each of the design proven in Phase 1 and to characterize and understand the techniques for designing the stack. The overall goal of Phase 3 is to demonstrate the feasibility of constructing a higher energy cavity from a number of smaller LTD stacks, to characterize and understand the way in which the constituent stacks combine, and to extend this demonstration LTD to serve as the basis for a 64 kJ pulse generator for Z-Pinch experiments.

A tentative opinion of modeling plasma formation in metallic wire Z pinch

International Nuclear Information System (INIS)

Ding Ning

2002-01-01

Numerous experiments in both single wire and in wire arrays have attracted much attention. For the wire array Z-pinch implosions the plasma formation in the metallic wire Z pinches is a key question. By means of analyzing a number of single-wire and multi-wire experiments, two models to describe the behavior of a wire array Z-pinch in initial phase are suggested. In this phase each wire carries a rising current and behaves independently in a way similar to that found in single wire Z-pinch experiments in which a comparable current in one wire is employed. Based on one- or/and two-dimensional magnetohydrodynamics (MHD) theory, one model is used to simulate the electrical explosion stage of the metallic wire, another is used to simulate the wire-plasma formation stage

Study of the internal structure, instabilities, and magnetic fields in the dense Z-pinch

International Nuclear Information System (INIS)

Ivanov, Vladimir V.

2016-01-01

Z-pinches are sources of hot dense plasma which generates powerful x-ray bursts and can been applied to various areas of high-energy-density physics (HEDP). The 26-MA Z machine is at the forefront of many of these applications, but important aspects of HEDP have been studied on generators at the 1 MA current level. Recent development of laser diagnostics and upgrade of the Leopard laser at Nevada Terawatt Facility (NTF) give new opportunities for the dense Z-pinch study. The goal of this project is the investigation of the internal structure of the stagnated Z pinch including sub-mm and micron-scale instabilities, plasma dynamics, magnetic fields, and hot spots formation and initiation. New plasma diagnostics will be developed for this project. A 3D structure and instabilities of the pinch will be compared with 3D MHD and spectroscopic modeling and theoretical analysis. The structure and dynamics of stagnated Z pinches has been studied with x-ray self-radiation diagnostics which derive a temperature map of the pinch with a spatial resolution of 70-150 µm. The regular laser diagnostics at 532 nm does not penetrate in the dense pinch due to strong absorption and refraction in trailing plasma. Recent experiments at NTF showed that shadowgraphy at the UV wavelength of 266 nm unfolds a fine structure of the stagnated Z-pinch with unprecedented detail. We propose to develop laser UV diagnostics for Z pinches with a spatial resolution 20 MG, suggested in micropinches, Cotton-Mouton and cutoff diagnostics will be applied. A picosecond optical Kerr shutter will be tested to increase a sensitivity of UV methods for application at multi-MA Z pinches. The proposal is based on the experimental capability of NTF. The Zebra generator produces 1-1.7 MA Z-pinches with electron plasma density of 10"2"0-10"2"1cm"-"3, electron temperature of 0.5-1 keV, and magnetic fields >10 MG. The Leopard laser was upgraded to energy of 90-J at 0.8 ns. This regime will be used for laser initiation

The Z-pinch as plasma lens for the focusing of heavy ion beams

International Nuclear Information System (INIS)

Elfers, M.

1992-04-01

In the present thesis the influence of a Z-pinch plasma on the shape of heavy-ion beams and the for the understanding of this interaction most important plasma parameters were studied. For this the Z-pinch at the heavy-ion accelerator UNILAC was operated. The magnet field gradients of up to (25 ± 3) T/m occuring in the Z-pinch lead to the plasma-lens effect - the focusing of a charged-particle beam traversing axially the Z-pinch. In this thesis for the first time the focusing of a heavy-ion beam by the azimutal magnetic field of a Z-pinch is described. Different beams with an original diameter of 10 mm were focused. The smallest measured beam diameter amounts to 1 mm half-width. The beam energy amounts to 11.4 MeV/u, which leads at gold as projectile matter to a beam energy of 2.25 GeV. (orig./HSI) [de

Study of the internal structure, instabilities, and magnetic fields in the dense Z-pinch

Energy Technology Data Exchange (ETDEWEB)

Ivanov, Vladimir V. [Univ. of Nevada, Reno, NV (United States)

2016-08-17

Z-pinches are sources of hot dense plasma which generates powerful x-ray bursts and can been applied to various areas of high-energy-density physics (HEDP). The 26-MA Z machine is at the forefront of many of these applications, but important aspects of HEDP have been studied on generators at the 1 MA current level. Recent development of laser diagnostics and upgrade of the Leopard laser at Nevada Terawatt Facility (NTF) give new opportunities for the dense Z-pinch study. The goal of this project is the investigation of the internal structure of the stagnated Z pinch including sub-mm and micron-scale instabilities, plasma dynamics, magnetic fields, and hot spots formation and initiation. New plasma diagnostics will be developed for this project. A 3D structure and instabilities of the pinch will be compared with 3D MHD and spectroscopic modeling and theoretical analysis. The structure and dynamics of stagnated Z pinches has been studied with x-ray self-radiation diagnostics which derive a temperature map of the pinch with a spatial resolution of 70-150 µm. The regular laser diagnostics at 532 nm does not penetrate in the dense pinch due to strong absorption and refraction in trailing plasma. Recent experiments at NTF showed that shadowgraphy at the UV wavelength of 266 nm unfolds a fine structure of the stagnated Z-pinch with unprecedented detail. We propose to develop laser UV diagnostics for Z pinches with a spatial resolution <5 μm to study the small-scale plasma structures, implement two-frame shadowgraphy/interferometry, and develop methods for investigation of strong magnetic fields. New diagnostics will help to understand better basic physical processes in Z pinches. A 3D internal structure of the pinch and characteristic instabilities will be studied in wire arrays with different configurations and compared with 3D MHD simulations and analytical models. Mechanisms of “enhanced heating” of Z-pinch plasma will be studied. Fast dynamics of stagnated

Evolution of the MHD sheet pinch

International Nuclear Information System (INIS)

Matthaeus, W.H.; Montgomery, D.

1979-01-01

A magnetohydrodynamic (MHD) problem of recurrent interest for both astrophysical and laboratory plasmas is the evolution of the unstable sheet pinch, a current sheet across which a dc magnetic field reverses sign. The evolution of such a sheet pinch is followed with a spectral-method, incompressible, two-dimensional, MHD turbulence code. Spectral diagnostics are employed, as are contour plots of vector potential (magnetic field lines), electric current density, and velocity stream function (velocity streamlines). The nonlinear effect which seems most important is seen to be current filamentation: the concentration of the current density onto sets of small measure near a mgnetic X point. A great deal of turbulence is apparent in the current distribution, which, for high Reynolds numbers, requires large spatial grids (greater than or equal to (64) 2 ). 11 figures, 1 table

Nonlinear development of the sausage instability in dense Z-pinches

International Nuclear Information System (INIS)

Colombant, D.; Mosher, D.

1989-01-01

In this paper, a 2d envelope model is described for the nonlinear development of the sausage instability in dense Z-pinches. Numerical solutions for various cases of interest are provided which lay the foundation for a quantitative model of nonthermal neutron emission in dense Z-pinches by determining the induced electric fields associated with the development of the instability

Numerical studies of neon gas-puff Z-pinch dynamic processes

International Nuclear Information System (INIS)

Ning Cheng; Yang Zhenhua; Ding Ning

2003-01-01

Dynamic processes of neon gas-puff Z-pinch are studied numerically in this paper. A high temperature plasma with a high density can be generated in the process. Based on some physical analysis and assumption, a set of equations of one-dimensional Lagrangian radiation magneto-hydrodynamic (MHD) and its code are developed to solve the problem. Spatio-temporal distributions of plasma parameters in the processes are obtained, and their dynamic variations show that the major results are self-consistent. The duration for the plasma pinched to centre, as well as the width and the total energy of the x-ray pulse caused by the Z-pinch are in reasonable agreement with experimental results of GAMBLE-II. A zipping effect is also clearly shown in the simulation

Effectiveness of Ford's belt reminder system in increasing seat belt use

OpenAIRE

Williams, A; Wells, J; Farmer, C

2002-01-01

Objectives: The study investigated the effectiveness in increasing seat belt use of Ford's belt reminder system, a supplementary system that provides intermittent flashing lights and chimes for five minutes if drivers are not belted.

Multi-scale characterization of an upcurrent turbiditic pinch-out

Science.gov (United States)

Daghdevirenian, L. J. P.; Migeon, S.; Rubino, J. L., Sr.; Raisson, F.

2017-12-01

Continental margins with a steep topographic profile between their continental shelf and the basin exhibit a sudden slope break at the base of their continental slope. This slope break favors strong erosion or a by-pass and a fast accumulation of sediments on the base of the continental slope due to the hydraulic jump phenomena. Such a process is responsible for the construction of thick accumulations of limited extension and generally disconnected from the feeding tributaries. These accumulations usually onlap against the continental slope but their modality of pinch out is still questioned and it is the subject of this work. The Tabernas basin is located in South East of Spain, in the continuity of the Sorbas basin. Recent field works allowed identifying a "sedimentary" onlap associated with a small-scale sandy turbidite system that we discovered near the so-called El Buho area. The superb quality of the outcrops revealed, the presence of three successive onlap structures consisting in each case of a direct contact between fluvial conglomerates / marines conglomerates / marine marls / turbidite sands. Reconstruction of paleo-current direction gives a flow direction around N00, from north to south, suggesting the outcrops are cutting the pinch out of the sandy system in a longitudinal direction. A longitudinal and vertical transition of facies can be thus observed from marines' conglomerates to turbidite sands, respectively over distances of 500 m and 70 m. The complete evolution of facies along the pinch out consists of thick conglomerates in the proximal part to sandy turbidite channels then lobes in the distal part. The three successive onlap structures are located inside the channelize part of the system, just above a slope break structure. The basal units of the pinch out consist of an alternation of conglomerates and sandy bed, while the overlying units exhibits more sandy dominated beds. In order to reconstruct the architecture of the pinch out and to

Scylla IV-P theta pinch

International Nuclear Information System (INIS)

Bailey, A.G.; Chandler, G.I.; Ekdahl, C.A. Jr.; Lillberg, J.W.; Machalek, M.D.; Seibel, F.T.

1976-01-01

Scylla IV-P is a flexible, linear theta pinch designed to investigate high-density linear concepts, end-stoppering, alternate heating methods, and plasma injection techniques relevant to a pure fusion reactor and/or a fusion-fission hybrid system. The construction and experimental arrangement of the device are briefly described

Nonlinear tearing modes in the reversed field pinch

International Nuclear Information System (INIS)

Miller, G.

1989-01-01

Finite-amplitude islands, which are the saturated states of tearing modes in the reversed field pinch, are calculated. These states are bifurcated noncylindrical equilibrium states. With σ(r) (σequivalentj x B/B 2 ) nonuniform across the plasma, as is consistent with experiment, a variety of m = 1 and m = 0 bifurcated equilibria are possible, instead of just the m = 1 helix calculated for uniform σ(r) by Taylor [in Pulsed High Beta Plasmas, edited by D. Evans (Pergamon, Oxford, 1976), p. 59]. Assuming the magnetic field lines in the reversed field pinch are weakly stochastic, the growth time of an unstable tearing mode is on the inertial time scale, as in the Taylor model, in constrast to growth on the resistive time scale predicted from nonlinear tearing mode theory when magnetic surfaces exist. The dependence of the saturated island width on radius of a conducting shell is investigated. Islands in the reversed field pinch often have magnetic wells in the island interior, which may result in improved confinement in the island regions

Space and time resolved observations of plasma dynamics in a compressional gas embedded Z-pinch

International Nuclear Information System (INIS)

Soto, L.; Chuaqui, H.; Favre, M.; Saavedra, R.; Wyndham, E.; Aliaga-Rossel, R.; Mitchell, I.

1996-01-01

Recent experiments in a gas embedded compressional Z-pinch are presented. The experiments have been carried out in H 2 at 1/3 atm, using a pulse power generator capable of delivering a dl/dt > 10 12 A/s. The pinch is initiated by a focused laser pulse, which is coaxial with a cylindrical DC microdischarge. This configuration results in double column pinch at early times, which at current rise evolves into a gas embedded compressional Z-pinch. Diagnostics used are Rogowski coil, single frame holographic interferometry, and holographic shadowgraphy, visible streak camera images from which current, density, line density, pinch radius and plasma motion are obtained. The pinch is characterized by a maximum on axis density which is much higher than the expected value from the filling pressure, with a Bennett temperature of 40 eV at 130 kA. The results shown confirm the high degree of compression achievable with the composite preionization scheme. (author). 4 figs., 5 refs

Numerical simulation of a Z-pinch compressed by imploding liner

International Nuclear Information System (INIS)

Bilbao, L.; Linhart, J.G.; Verri, G.; Bernal, L.

2001-01-01

The spark created in a neck of a dense Z-pinch can ignite a fusion detonation in the adjacent D-T plasma channel. Using an appropriate transition between the ignited D-T plasma and an inertially confined cylinder of highly compressed advanced fuel plasma it is possible to amplify the spark energy to a level adequate for the ignition of a detonation wave in the advanced fuel. An m=0 instability of a Z-pinch carrying a current of the order of 10 MA, with a rise time inferior to 10 ns can generate a spark capable of igniting a fusion detonation in the adjacent D-T plasma channel. Such μZ-pinch may be produced by a fast implosion of a cylindrical liner, while a conical channel properly chosen can amplify the spark energy. In order to derive some general rules for the parameters of the spark, the transition, the cylinder of advanced fuel and the liner different numerical models were used. We present here a review of these results and an outline of a possible experimental arrangement for obtaining such a Z-pinch compression

Pinch grafting for chronic venous leg ulcers in general practice

OpenAIRE

Steele, Keith

1985-01-01

Twenty-five patients with chronic venous leg ulcers were treated in general practice by pinch grafting. Fifteen of the ulcers (60%) were completely healed one year after grafting. Prior to grafting 19 patients (76%) complained of daily pain in the ulcer. These patients experienced complete relief from pain after grafting. Pinch grafting is a simple, safe and effective therapy when applied in a domiciliary environment.

Numerical simulation on the screw pinch by 2-D MHD pinch code 'topics' including impurities and neutrals effects

International Nuclear Information System (INIS)

Nagata, A.; Ashida, H.; Okamoto, M.; Hirano, K.

1981-03-01

Two dimentional fluid simulation code ''TOPICS'' is developed for the STP-2, the shock heated screw pinch at Nagoya. It involves the effects of impurity ions and neutral atoms. In order to estimate the radiation losses, the impurity continuity equations with ionizations and recombinations are solved simultaneously with the plasma fluid equations. The results are compared with the coronal equilibrium model. It is found that the coronal equilibrium model underestimates the radiation losses from shock heated pinch plasmas in its initial dynamic phase. The present calculations including impurities and neutrals show the importance of the radiation losses from the plasma of the STP-2. Introducing the anomalous resistivity caused by the ion acoustic instability, the observed magnetic field penetration is explained fairly well. (author)

Finite Larmor radius effects on Z-pinch stability

International Nuclear Information System (INIS)

Scheffel, J.; Faghihi, M.

1987-10-01

The effect of finite Larmor radius (FLR) on the stability of m=1 small axial wavelength kinks in a z-pinch with purely poloidal magnetic field is investigated. We use the Incompressible FLR MHD model; a collisionless fluid model which consistently includes the relevant FLR terms due to ion gyroviscosity, Hall effect and electron diamagnetism. With FLR terms absent, the Kadomtsev criterion of ideal MHD 2rdp/dr+m 2 B 2 /μ 0 >=0 predicts instability for internal modes unless the current density becomes singular at the centre of the pinch. The same result is obtained in the present model, with FLR terms absent. When the FLR terms are included, a normal mode analysis of the linearized equations yields the following results. Marginally unstable (ideal) modes are stabilized by gyroviscosity. The Hall terms have a damping, however not stabilizing, effect, in agreement with earlier work. Specifying a constant current and particle density equilibrium, the effect of electron diamagnetism vanishes. For a z-pinch with parameters relevant to the EXTRAP experiment, the m=1 modes are then fully stabilized over the cross-section for wavelengths λ/a max =3-5x10 18 m -1 is found, above which gyroviscous stabilization near the plasma boundary becomes insufficient. The result holds for wavelengths close to, or smaller than, the pinch radius and for realistic equilibrium profiles. This limit is far below the required limit for a reactor with contained alpha particles, which is in excess of 10 20 m -1 . (authors)

Storm-time radiation belt electron dynamics: Repeatability in the outer radiation belt

Science.gov (United States)

Murphy, K. R.; Mann, I. R.; Rae, J.; Watt, C.; Boyd, A. J.; Turner, D. L.; Claudepierre, S. G.; Baker, D. N.; Spence, H. E.; Reeves, G. D.; Blake, J. B.; Fennell, J. F.

2017-12-01

During intervals of enhanced solar wind driving the outer radiation belt becomes extremely dynamic leading to geomagnetic storms. During these storms the flux of energetic electrons can vary by over 4 orders of magnitude. Despite recent advances in understanding the nature of competing storm-time electron loss and acceleration processes the dynamic behavior of the outer radiation belt remains poorly understood; the outer radiation belt can exhibit either no change, an enhancement, or depletion in radiation belt electrons. Using a new analysis of the total radiation belt electron content, calculated from the Van Allen probes phase space density (PSD), we statistically analyze the time-dependent and global response of the outer radiation belt during storms. We demonstrate that by removing adiabatic effects there is a clear and repeatable sequence of events in storm-time radiation belt electron dynamics. Namely, the relativistic (μ=1000 MeV/G) and ultra-relativistic (μ=4000 MeV/G) electron populations can be separated into two phases; an initial phase dominated by loss followed by a second phase dominated by acceleration. At lower energies, the radiation belt seed population of electrons (μ=150 MeV/G) shows no evidence of loss but rather a net enhancement during storms. Further, we investigate the dependence of electron dynamics as a function of the second adiabatic invariant, K. These results demonstrate a global coherency in the dynamics of the source, relativistic and ultra-relativistic electron populations as function of the second adiabatic invariant K. This analysis demonstrates two key aspects of storm-time radiation belt electron dynamics. First, the radiation belt responds repeatably to solar wind driving during geomagnetic storms. Second, the response of the radiation belt is energy dependent, relativistic electrons behaving differently than lower energy seed electrons. These results have important implications in radiation belt research. In particular

Belt attachment and system

Energy Technology Data Exchange (ETDEWEB)

Schneider, Abraham D.; Davidson, Erick M.

2018-03-06

Disclosed herein is a belt assembly including a flexible belt with an improved belt attachment. The belt attachment includes two crossbars spaced along the length of the belt. The crossbars retain bearings that allow predetermined movement in six degrees of freedom. The crossbars are connected by a rigid body that attaches to the bearings. Implements that are attached to the rigid body are simply supported but restrained in pitching rotation.

Pinching evidences in a miniature plasma focus with fast pseudospark switch

International Nuclear Information System (INIS)

Hassan, S M; Zhang, T; Patran, A; Rawat, R S; Springham, S V; Tan, T L; Wong, D; Wang, W; Lee, S; Gribkov, V A; Mohanty, S R; Lee, P

2006-01-01

We report the observations of pinching in a miniature plasma focus (PF) (58-160 J) operated in repetitive mode using fast pseudospark switch (PSS). The size of the device, which includes the capacitor bank, PSS and the focus chamber, is of the order of 22 cm x 22 cm x 38 cm. Several diagnostic tools, the gated imager, streak camera, current and voltage probe, are employed simultaneously to confirm the occurrence of pinching in this fast miniature PF device. The device is optimized for operation in neon and hydrogen as the working gas. The best focus formation was obtained at pressures between 0.5 to 8.0 mbar for neon and between 7.0 to 15.0 mbar for hydrogen. When the system was operated at 100 J with hydrogen as the filling gas, the typical dip in the current derivative signal and the typical peak in the voltage signal associated with pinch compression, are observed to be most intense indicating efficient pinching in the miniature PF device

Studies of implosion processes of nested tungsten wire-array Z-pinch

International Nuclear Information System (INIS)

Ning Cheng; Ding Ning; Liu Quan; Yang Zhenhua

2006-01-01

Nested wire-array is a kind of promising structured-load because it can improve the quality of Z-pinch plasma and enhance the radiation power of X-ray source. Based on the zero-dimensional model, the assumption of wire-array collision, and the criterion of optimized load (maximal load kinetic energy), optimization of the typical nested wire-array as a load of Z machine at Sandia Laboratory was carried out. It was shown that the load has been basically optimized. The Z-pinch process of the typical load was numerically studied by means of one-dimensional three-temperature radiation magneto-hydrodynamics (RMHD) code. The obtained results reproduce the dynamic process of the Z-pinch and show the implosion trajectory of nested wire-array and the transfer process of drive current between the inner and outer array. The experimental and computational X-ray pulse was compared, and it was suggested that the assumption of wire-array collision was reasonable in nested wire-array Z-pinch at least for the current level of Z machine. (authors)

Experimental studies of Z-pinches of mixed wire array with aluminum and tungsten

International Nuclear Information System (INIS)

Ning Cheng; Li Zhenghong; Hua Xinsheng; Xu Rongkun; Peng Xianjue; Xu Zeping; Yang Jianlun; Guo Cun; Jiang Shilun; Feng Shuping; Yang Libing; Yan Chengli; Song Fengjun; Smirnov, V.P.; Kalinin, Yu.G.; Kingsep, A.S.; Chernenko, A.S.; Grabovsky, E.V.

2004-01-01

In the form of joint experiment between China and Russia, the experimental studies of Z-pinches of mixed wire array of aluminum (A1) and tungsten (W) were carried out on S-300 generator, which was located on Kurchatov Institute of Russia. The experimental results were compared with those of single A1 array and single W array, respectively. There are obvious difference between mixed one and single one in their photon spectral distributions. The intensity of K-series emission lines from the mixed wire array Z-pinch is lower than that from single A1 array. The radiated lines with wavelengths less than 1.6 nm were not found in single W array Z-pinches. In the Z-pinch processes, the area radiating x-rays in mixed wire array is smaller than that of single A1 array, but is slightly lower than that from single W array. The FWHM of x-ray pulse with a maximal power 0.3-0.5 TW and total energy 10-20 kJ is about 25 ns, which radiated from Z-pinches with a radial convergence of 4-5 on S-300 generator. The shadow photograph of the mixed wire-array Z-pinch plasma by laser probe shows that the core-corona configuration was formed and the corona was moving toward the center axis during the wire-array plasma formation, that the interface of the plasma is not clear, and that there are a number structures inside. They also suggests that there was an obvious development of Magneto Rayleigh-Taylor instability in the Z-pinch process as well

The quest for a z-pinch based fusion energy source—a historical perspective

Science.gov (United States)

Sethian, John

1997-05-01

Ever since 1958, when Oscar Anderson observed copious neutrons emanating from a "magnetically self-constricted column of deuterium plasma," scientists have attempted to develop the simple linear pinch into a fusion power source. After all, simple calculations show that if one can pass a current of slightly less than 2 million amperes through a stable D-T plasma, then one could achieve not just thermonuclear break-even, but thermonuclear gain. Moreover, several reactor studies have shown that a simple linear pinch could be the basis for a very attractive fusion system. The problem is, of course, that the seemingly simple act of passing 2 MA through a stable pinch has proven to be quite difficult to accomplish. The pinch tends to disrupt due to instabilities, either by the m=0 (sausage) or m=1 (kink) modes. Curtailing the growth of these instabilities has been the primary thrust of z-pinch fusion research, and over the years a wide variety of formation techniques have been tried. The early pinches were driven by relatively slow capacitive discharges and were formed by imploding a plasma column. The advent of fast pulsed power technology brought on a whole new repertoire of formation techniques, including: fast implosions, laser or field-enhanced breakdown in a uniform volume of gas, a discharge inside a small capillary, a frozen deuterium fiber isolated by vacuum, and staged concepts in which one pinch implodes upon another. And although none of these have yet to be successful, some have come tantalizingly close. This paper will review the history of this four-decade long quest for fusion power.

The design and implementation of a windowing interface pinch force measurement system

Science.gov (United States)

Ho, Tze-Yee; Chen, Yuanu-Joan; Chung, Chin-Teng; Hsiao, Ming-Heng

2010-02-01

This paper presents a novel windowing interface pinch force measurement system that is basically based on an USB (Universal Series Bus) microcontroller which mainly processes the sensing data from the force sensing resistance sensors mounted on five digits. It possesses several friendly functions, such as the value and curve trace of the applied force by a hand injured patient displayed in real time on a monitoring screen, consequently, not only the physician can easily evaluate the effect of hand injury rehabilitation, but also the patients get more progressive during the hand physical therapy by interacting with the screen of pinch force measurement. In order to facilitate the pinch force measurement system and make it friendly, the detail hardware design and software programming flowchart are described in this paper. Through a series of carefully and detailed experimental tests, first of all, the relationship between the applying force and the FSR sensors are measured and verified. Later, the different type of pinch force measurements are verified by the oscilloscope and compared with the corresponding values and waveform traces in the window interface display panel to obtain the consistency. Finally, a windowing interface pinch force measurement system based on the USB microcontroller is implemented and demonstrated. The experimental results show the verification and feasibility of the designed system.

Design of the PST: A Diagnostic for 1-D Imaging of Fast Z-Pinch Power Emissions

International Nuclear Information System (INIS)

Rochau, Gregory A.; Derzon, Mark S.; Chandler, Gordon A.; Lazier, Steven Earl

2000-01-01

Fast Z-pinch technology developed on the Z machine at Sandia National Laboratories can produce up to 230 TW of thermal x-ray power for applications in inertial confinement fusion (ICF) and weapons physics experiments. During implosion, these Z-pinches develop Rayleigh-Taylor (R-T) instabilities which are very difficult to diagnose and which functionally diminish the overall pinch quality. The Power-Space-Time (PST) instrument is a newly configured diagnostic for measuring the pinch power as a function of both space and time in a Z-pinch. Placing the diagnostic at 90 degrees from the Z-pinch axis, the PST provides a new capability in collecting experimental data on R-T characteristics for making meaningful comparisons to magneto-hydrodynamic computer models. This paper is a summary of the PST diagnostic design. By slit-imaging the Z-pinch x-ray emissions onto a linear scintillator/fiber-optic array coupled to a streak camera system, the PST can achieve ∼100 microm spatial resolution and ∼1.3 ns time resolution. Calculations indicate that a 20 microm thick scintillating detection element filtered by 1,000 angstrom of Al is theoretically linear in response to Plankian x-ray distributions corresponding to plasma temperatures from 40 eV to 150 eV, By calibrating this detection element to x-ray energies up to 5,000 eV, the PST can provide pinch power as a function of height and time in a Z-pinch for temperatures ranging from ∼40 eV to ∼400 eV. With these system pm-meters, the PST can provide data for an experimental determination of the R-T mode number, amplitude, and growth rate during the late-time pinch implosion

Seeded perturbations in wire array z-pinches

International Nuclear Information System (INIS)

Robinson, Allen Conrad; Kantsyrev, Victor Leonidovich; Wunsch, Scott Edward; Oliver, Bryan Velten; Lebedev, Sergey V.; Safronova, Alla S.; Maxwell, J.; McKenney, John Lee; Ampleford, David J.; Rapley, J.; Bott, S.C.; Palmer, J.B.A.; Bland, Simon Nicholas; Jones, Brent Manley; Chittenden, Jeremy Paul; Garasi, Christopher Joseph; Hall, Gareth Neville; Mehlhorn, Thomas Alan; Deeney, Christopher

2004-01-01

The impact of 3D structure on wire array z-pinch dynamics is a topic of current interest, and has been studied by the controlled seeding of wire perturbations. First, Al wires were etched at Sandia, creating 20% radial perturbations with variable axial wavelength. Observations of magnetic bubble formation in the etched regions during experiments on the MAGPIE accelerator are discussed and compared to 3D MHD modeling. Second, thin NaF coatings of 1 mm axial extent were deposited on Al wires and fielded on the Zebra accelerator. Little or no axial transport of the NaF spectroscopic dopant was observed in spatially resolved K-shell spectra, which places constraints on particle diffusivity in dense z-pinch plasmas. Finally, technology development for seeding perturbations is discussed

Recent studies of Reversed-Field Pinch reactors

International Nuclear Information System (INIS)

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

1981-01-01

The reactor prognoses of a class of confinement scheme that relies primarily on self-fields induced by axial currents flowing within a plasma column are presented. The primary focus has been placed on the toroidal Reversed-Field Pinch (RFP). At the limit of very large current densities is the gas-embedded Dense Z-Pinch (DZP), a small-radius, linear device. Past conventional RFP reactor designs are reviewed. The extention of these conventional RFP reactors to DD advanced-fuel operation is described. The implications are summarized of operating higher-density, compact RFPs as reactors, wherein the current density rather than physical dimensions are scaled. Lastly, the application of very high current densities supported in a sub-millimeter linear current channel, as embodied in the DZP reactor, is reviewed

Riding the belt

Energy Technology Data Exchange (ETDEWEB)

Potts, A

1998-04-01

Recent developments in conveyor systems have focused on accessories rather than the belt itself. Radio frequency identification (RFID) is a technology using transponders embedded in conveyor belts and this is the latest development at the German firm Contitech. The system described in the articles developed with Moers, features transponders for cooling, controlling and monitoring conveyor belts. Other developments mentioned include a JOKI drum motor featuring a fully integrated gearbox and electric motor enclosed in a steel shell, from Interoll; a new scraper cleaning system from Hosch, new steel cord belting from Fenner, a conveying system for Schleenhain lignite opencast mine by FAM Foerdelantigen Magdeburg; new bearings from Nadella (the sales arm of Intersoll-Rand), an anti-shock belt transfer table from Rosta and new caliper disc brakes from GE Industrial.

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

International Nuclear Information System (INIS)

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

1999-01-01

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

Synaptic ribbon. Conveyor belt or safety belt?

Science.gov (United States)

Parsons, T D; Sterling, P

2003-02-06

The synaptic ribbon in neurons that release transmitter via graded potentials has been considered as a conveyor belt that actively moves vesicles toward their release sites. But evidence has accumulated to the contrary, and it now seems plausible that the ribbon serves instead as a safety belt to tether vesicles stably in mutual contact and thus facilitate multivesicular release by compound exocytosis.

Plasma confinement of Nagoya high-beta toroidal-pinch experiments

International Nuclear Information System (INIS)

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

1977-01-01

Two different types of high-β toroidal pinch experiments, STP [1] and CCT [2,3], have been done to study the confinement of the plasma produced by a theta-pinch. The STP is an axisymmetric toroidal pinch of high-β tokamak type, while the CCT consists of multiply connected periodic toroidal traps. Internal current-carrying copper rings are essential to the CCT. Since both apparatuses use the same fast capacitor bank system, they produce rather similar plasma temperatures and densities. The observed laser scattering temperature and density is about 50 eV and 4x10 15 cm -3 , respectively, when the filling pressure is 5 mtorr. In the STP experiment, strong correlations are found between the βsub(p) value and the amplitude of m=2 mode. It has a minimum around the value of βsub(p) of 0.8. The disruptive instability is observed to expand the pinched plasma column without lowering the plasma temperature. Just before the disruption begins, the q value around the magnetic axis becomes far less than 1 and an increase of the amplitude of m=2 mode is seen. The CCT also shows rapid plasma expansion just before the magnetic field reaches its maximum. Then the trap is filled up with the plasma by this irreversible expansion and stable plasma confinement is achieved. The energy confinement time of the CCT is found to be about 35 μs. (author)

Pinch analysis for bioethanol production process from lignocellulosic biomass

International Nuclear Information System (INIS)

Fujimoto, S.; Yanagida, T.; Nakaiwa, M.; Tatsumi, H.; Minowa, T.

2011-01-01

Bioethanol produced from carbon neutral and renewable biomass resources is an attractive process for the mitigation of greenhouse gases from vehicle exhaust. This study investigated energy utilization during bioethanol production from lignocellulose while avoiding competition with food production from corn and considering the potential mitigation of greenhouse gases. Process design and simulations were performed for bioethanol production using concentrated sulfuric acid. Mass and heat balances were obtained by process simulations, and the heat recovery ratio was determined by pinch analysis. An energy saving of 38% was achieved. However, energy supply and demand were not effectively utilized in the temperature range from 95 to 100 o C. Therefore, a heat pump was used to improve the temperature range of efficient energy supply and demand. Results showed that the energy required for the process could be supplied by heat released during the process. Additionally, the power required was supplied by surplus power generated during the process. Thus, pinch analysis was used to improve the energy efficiency of the process. - Highlights: → Effective energy utilization of bioethanol production was studied by using pinch analysis. → It was found that energy was not effectively utilized in the temperature range from 95 to 100 o C. → Use of a heat pump was considered to improve the ineffective utilization. → Then, remarkable energy savings could be achieved by it. → Pinch analysis effectively improved the energy efficiency of the bioethanol production.

Reconsideration of the m=0 Z-pinch stability

International Nuclear Information System (INIS)

Scheffel, J.; Coppins, M.

1993-01-01

Possible paths for obtaining linear stability against the m=0 mode in the Z-pinch are studied. Using a generalized energy principle, the necessary and sufficient Chew-Goldberger-Low (CGL) m=0 stability criterion is derived. This criterion is less restrictive than that of ideal MHD, although it also requires the boundary plasma pressure to be finite. It is shown that the edge pressure cannot be stably upheld by a surface current. By instead assuming a finite pressure external gas, it is found that an edge pressure to on-axis pressure ratio of 0.5 is required for stability of a constant current density profile. A parabolic current density profile lowers the limit to the value 0.17. The growth rates are shown to be monotonically decreasing as a function of the external gas pressure. Detailed derivations of the boundary conditions are also given. The results aid in clarifying the experimental stability of four major Z-pinch experiments. Finite Larmor radius stabilization is hence required to maintain stability in future fibre pinch experiments in vacuum, implying line densities less than 10 19 m -1 . (author). 28 refs, 10 figs

Two-dimensional integrated Z-pinch ICF design simulations

International Nuclear Information System (INIS)

Lash, J.S.

1999-01-01

The dynamic hohlraum ICF concept for a Z-pinch driver utilizes the imploding wire array collision with a target to produce a radiation history suitable for driving an embedded inertial confinement fusion (ICF) capsule. This target may consist of various shaped layers of low-density foams or solid-density materials. The use of detailed radiation magneto-hydrodynamic (RMHD) modeling is required for understanding and designing these complex systems. Critical to producing credible simulations and designs is inclusion of the Rayleigh-Taylor unstable wire-array dynamics; the bubble and spike structure of the collapsing sheath may yield regions of low-opacity enhancing radiation loss as well as introduce non-uniformities in the capsule's radiation drive. Recent improvements in LASNEX have allowed significant progress to be made in the modeling of unstable z-pinch implosions. Combining this with the proven ICF capsule design capabilities of LASNEX, the authors now have the modeling tools to produce credible, fully-integrated ICF dynamic hohlraum simulations. They present detailed two-dimensional RMHD simulations of recent ICF dynamic hohlraum experiments on the Sandia Z-machine as well as design simulations for the next-generation Z-pinch facility and future high-yield facility

Two-dimensional integrated Z-pinch ICF design simulations

Energy Technology Data Exchange (ETDEWEB)

Lash, J.S.

1999-07-01

The dynamic hohlraum ICF concept for a Z-pinch driver utilizes the imploding wire array collision with a target to produce a radiation history suitable for driving an embedded inertial confinement fusion (ICF) capsule. This target may consist of various shaped layers of low-density foams or solid-density materials. The use of detailed radiation magneto-hydrodynamic (RMHD) modeling is required for understanding and designing these complex systems. Critical to producing credible simulations and designs is inclusion of the Rayleigh-Taylor unstable wire-array dynamics; the bubble and spike structure of the collapsing sheath may yield regions of low-opacity enhancing radiation loss as well as introduce non-uniformities in the capsule's radiation drive. Recent improvements in LASNEX have allowed significant progress to be made in the modeling of unstable z-pinch implosions. Combining this with the proven ICF capsule design capabilities of LASNEX, the authors now have the modeling tools to produce credible, fully-integrated ICF dynamic hohlraum simulations. They present detailed two-dimensional RMHD simulations of recent ICF dynamic hohlraum experiments on the Sandia Z-machine as well as design simulations for the next-generation Z-pinch facility and future high-yield facility.

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

International Nuclear Information System (INIS)

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

2001-01-01

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

LASL toroidal reversed-field pinch program

International Nuclear Information System (INIS)

Baker, D.A.; Buchenauer, C.J.; Burkhardt, L.C.

1978-01-01

The determination of the absolute energy loss due to radiation from impurities in the LASL toroidal reversed-field pinch experiment ZT-S is reported. The measurements show over half of the energy loss is accounted for by this mechanism. Thomson scattering electron density measurements indicate only a gradual increase in temperature as the filling pressure is reduced indicating an increased energy loss at lower pressures. Cylindrical and toroidal simulations of the experiment indicate either that a highly radiative pinch boundary or anomalous transport are needed to match the experimental results. New effects on the equilibrium due to plasma flows induced by the toroidal geometry are predicted by the toroidal simulations. The preliminary results on the low temperature discharge cleaning of the ZT-S torus are reported. A description of the upgrade of the ZT-S experiment and the objectives, construction and theoretical predictions for the new ZT-40 experiment are given

MHD turbulence models for the reversed field pinch

International Nuclear Information System (INIS)

Gimblett, C.G.; Watkins, M.L.

1976-01-01

A kinematic model which describes the effect of isotropic, non-mirror symmetric turbulence on a mean magnetic field is used to examine the temporal behaviour of magnetic field in high beta pinch experiments. Solutions to the model can indicate the formation of a steady-state, force-free configuration that corresponds to the state of lowest magnetic energy and the reversal of the toroidal magnetic field at the plasma boundary in accordance with experimental observations on toroidal pinches such as ZETA and HBTX. This model neglects both the dynamic interaction between fluid and field and the associated anisotropy. These effects are examined in a further model. (author)

Pinched hysteresis behavior in a PID-controlled resistor

Directory of Open Access Journals (Sweden)

M.A. Carrasco-Aguilar

2018-06-01

Full Text Available A current-controlled grounded resistor that exhibits a frequency-dependent pinched hysteresis loop is described. A mathematical model describing this behavior is derived and validated numerically, which has the form of a Proportional Integral-Derivative (PID controller. The proposed topology is build by using AD844 commercially available active device configured as second-generation current conveyor and experimental tests are compared with numerical simulations, showing a good agreement among them. Moreover, the proposed PID-controlled resistor can be reconfigured in order to be used in future applications such as programmable analog circuits. Keyword: Pinched hysteresis, Current conveyors, Nonlinear resistor, Proportional-Integral-Derivative Controller

Review of effects of dielectric coatings on electrical exploding wires and Z pinches

Science.gov (United States)

Wu, Jian; Li, Xingwen; Li, Mo; Li, Yang; Qiu, Aici

2017-10-01

As the most powerful x-ray source in the laboratories, the wire array Z pinches have been of great relevance to inertial confinement fusions, laboratory astrophysics, and other high-energy density applications. In order to produce x-ray with greater power and higher efficiency, the dynamics of wire array has been investigated extensively, and various methods have been proposed to improve the implosion quality of the wire array. This review focuses on the experimental and theoretical investigations regarding the effects of the dielectric coatings on electrical exploding wires and Z pinches. Since the early 2000, the electrical wire explosion related to the first stage of the wire array Z pinches has been studied extensively, and the results indicated that the dielectric coatings can significantly increase the joule energy deposition into a wire in the initial stage, and even the corona free explosion of tungsten wires can be achieved. Recently, there is an increasing interest in the dynamics of insulated wire array Z pinches. By applying dielectric coatings, the ablation process is suppressed, the x-ray start time is delayed, and the possibility of multi-peak radiation is decreased. This review is organized by the evolution dynamics of wire array Z pinches, and a broad introduction to relevant scientific concepts and various other applications are presented. According to the current research status, the challenges, opportunities and further developments of Z pinch loads using dielectric coatings are proposed to further promote the researches and their applications.

Review of effects of dielectric coatings on electrical exploding wires and Z pinches

International Nuclear Information System (INIS)

Wu, Jian; Li, Mo; Li, Yang; Li, Xingwen; Qiu, Aici

2017-01-01

As the most powerful x-ray source in the laboratories, the wire array Z pinches have been of great relevance to inertial confinement fusions, laboratory astrophysics, and other high-energy density applications. In order to produce x-ray with greater power and higher efficiency, the dynamics of wire array has been investigated extensively, and various methods have been proposed to improve the implosion quality of the wire array. This review focuses on the experimental and theoretical investigations regarding the effects of the dielectric coatings on electrical exploding wires and Z pinches. Since the early 2000, the electrical wire explosion related to the first stage of the wire array Z pinches has been studied extensively, and the results indicated that the dielectric coatings can significantly increase the joule energy deposition into a wire in the initial stage, and even the corona free explosion of tungsten wires can be achieved. Recently, there is an increasing interest in the dynamics of insulated wire array Z pinches. By applying dielectric coatings, the ablation process is suppressed, the x-ray start time is delayed, and the possibility of multi-peak radiation is decreased. This review is organized by the evolution dynamics of wire array Z pinches, and a broad introduction to relevant scientific concepts and various other applications are presented. According to the current research status, the challenges, opportunities and further developments of Z pinch loads using dielectric coatings are proposed to further promote the researches and their applications. (topical review)

High-energy electron acceleration in the gas-puff Z-pinch plasma

Energy Technology Data Exchange (ETDEWEB)

Takasugi, Keiichi, E-mail: takasugi@phys.cst.nihon-u.ac.jp [Institute of Quantum Science, Nihon University, 1-8 Kanda-Surugadai, Chiyoda, Tokyo 101-8308 (Japan); Miyazaki, Takanori [Institute of Quantum Science, Nihon University, 1-8 Kanda-Surugadai, Chiyoda, Tokyo 101-8308, Japan and Dept. Innovation Systems Eng., Utsunomiya University, 7-1-2 Yoto, Utsunomiya, Tochigi 321-8585 (Japan); Nishio, Mineyuki [Anan National College of Technology, 265 Aoki, Minobayashi, Anan, Tokushima 774-0017 (Japan)

2014-12-15

The characteristics of hard x-ray generation were examined in the gas-puff z-pinch experiment. The experiment on reversing the voltage was conducted. In both of the positive and negative discharges, the x-ray was generated only from the anode surface, so it was considered that the electrons were accelerated by the induced electromagnetic force at the pinch time.

Collisional tearing in a field-reversed sheet pinch assuming nonparallel propagation

International Nuclear Information System (INIS)

Quest, K.B.; Coroniti, F.V.

1985-01-01

We examine the linear stability properties of the collisional tearing mode in a reversed-field sheet pinch assuming that the wave vector is not parallel to B, where B is the equilibrium magnetic field. We show that pressure balance in the direction of the equilibrium current requires a nonzero perturbed current component deltaJ/sub z/ that is driven toward tyhe center of the pinch. At the center of the pinch, deltaJ/sub z/ goes to zero, and momentum is balanced by coupling to the ion-acoustic mode. In order to achieve current closure, a large perturbed field-aligned current is generated that is strongly localized about the dissipative tearing layer. The relation of this work to the collisionless case is discussed

Computer modeling of a small neon gas-puff pinch

International Nuclear Information System (INIS)

Ullschmied, J.

1996-01-01

The macroscopic dynamics of a cylindrical gas-puff pinch and conditions of radiation plasma collapse are studied by using a one-dimensional ('mechanical') computer model. Besides the Joule plasma heating, compressional heating, magnetic field freezing in a plasma and recombination losses, also the real temperature- and density-dependences of radiation plasma loss are taken into account. The results of calculations are compared with experimental data taken from a small neon-puff z-pinch experiment operated at the Institute of Plasma Physics in Prague. (author). 7 figs., 11 refs

Experimental study of CF4 conical theta pinch plasma expanding into vacuum

International Nuclear Information System (INIS)

Pedrow, P.D.; Nasiruddin, A.M.

1989-01-01

Langmuir probe, photodiode, and optical multichannel analyzer (OMA) measurements have been made on a pulsed CF 4 conical theta pinch plasma. A cloud of CF 4 gas was puffed into a conical theta pinch coil, converted to plasma, and propelled into the vacuum region ahead of the expanding gas cloud. At a position 67 cm away from the conical theta pinch coil, the plasma arrived in separate packets that were about 20 μs in duration. The average drift velocity of these packets corresponded to an energy of about 3 eV. The OMA measurements showed that the second packet contained neutral atomic fluorine as well as charged particles

High energy density Z-pinch plasmas using flow stabilization

Energy Technology Data Exchange (ETDEWEB)

Shumlak, U., E-mail: shumlak@uw.edu; Golingo, R. P., E-mail: shumlak@uw.edu; Nelson, B. A., E-mail: shumlak@uw.edu; Bowers, C. A., E-mail: shumlak@uw.edu; Doty, S. A., E-mail: shumlak@uw.edu; Forbes, E. G., E-mail: shumlak@uw.edu; Hughes, M. C., E-mail: shumlak@uw.edu; Kim, B., E-mail: shumlak@uw.edu; Knecht, S. D., E-mail: shumlak@uw.edu; Lambert, K. K., E-mail: shumlak@uw.edu; Lowrie, W., E-mail: shumlak@uw.edu; Ross, M. P., E-mail: shumlak@uw.edu; Weed, J. R., E-mail: shumlak@uw.edu [Aerospace and Energetics Research Program, University of Washington, Seattle, Washington, 98195-2250 (United States)

2014-12-15

The ZaP Flow Z-Pinch research project[1] at the University of Washington investigates the effect of sheared flows on MHD instabilities. Axially flowing Z-pinch plasmas are produced that are 100 cm long with a 1 cm radius. The plasma remains quiescent for many radial Alfvén times and axial flow times. The quiescent periods are characterized by low magnetic mode activity measured at several locations along the plasma column and by stationary visible plasma emission. Plasma evolution is modeled with high-resolution simulation codes – Mach2, WARPX, NIMROD, and HiFi. Plasma flow profiles are experimentally measured with a multi-chord ion Doppler spectrometer. A sheared flow profile is observed to be coincident with the quiescent period, and is consistent with classical plasma viscosity. Equilibrium is determined by diagnostic measurements: interferometry for density; spectroscopy for ion temperature, plasma flow, and density[2]; Thomson scattering for electron temperature; Zeeman splitting for internal magnetic field measurements[3]; and fast framing photography for global structure. Wall stabilization has been investigated computationally and experimentally by removing 70% of the surrounding conducting wall to demonstrate no change in stability behavior.[4] Experimental evidence suggests that the plasma lifetime is only limited by plasma supply and current waveform. The flow Z-pinch concept provides an approach to achieve high energy density plasmas,[5] which are large, easy to diagnose, and persist for extended durations. A new experiment, ZaP-HD, has been built to investigate this approach by separating the flow Z-pinch formation from the radial compression using a triaxial-electrode configuration. This innovation allows more detailed investigations of the sheared flow stabilizing effect, and it allows compression to much higher densities than previously achieved on ZaP by reducing the linear density and increasing the pinch current. Experimental results and

Comparative study of millennials' (age 20-34 years) grip and lateral pinch with the norms.

Science.gov (United States)

Fain, Elizabeth; Weatherford, Cara

Cross-sectional research design. Clinical practice continues to use normative data for grip and pinch measurements that were established in 1985. There is no updated norms despite different hand usage patterns in today's society. Measuring and comparing grip and pinch strengths with normative data is a valid method to determine hand function. This research was implemented to compare the grip and pinch measurements obtained from healthy millennials to the established norms and to describe hand usage patterns for millennials. Grip and lateral pinch measurements were obtained from a sample of 237 healthy millennials (ages 20-34 years). Strength scores were statistically lower that older normative data in all millennial grip strengths, with the exception of the women in the age group of 30-34 years. Specifically, this statistically significant trend was observed in all male grip strengths, as well as in women in the age group of 20-24 years (bilateral grip) and 25-29 years (right grip). However, the lateral pinch data reflected was similar to the older norms with variances of 0.5-1 kg. Current data reflect statistically significant differences from the norms for all male grip measurements, as well as for women in the age group of 20-24 years (bilateral grip) and 25-29 years (right grip). No statistical significance was observed in the independent-sample t tests for the lateral pinch in men of all age groups. Statistical significance was noted for lateral pinch for female age groups for the left hand (20-24 years) and for bilateral lateral pinches (30-34 years). IV. Copyright © 2016 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.

A simplified MHD model of capillary Z-Pinch compared with experiments

Energy Technology Data Exchange (ETDEWEB)

Shapolov, A.A.; Kiss, M.; Kukhlevsky, S.V. [Institute of Physics, University of Pecs (Hungary)

2016-11-15

The most accurate models of the capillary Z-pinches used for excitation of soft X-ray lasers and photolithography XUV sources currently are based on the magnetohydrodynamics theory (MHD). The output of MHD-based models greatly depends on details in the mathematical description, such as initial and boundary conditions, approximations of plasma parameters, etc. Small experimental groups who develop soft X-ray/XUV sources often use the simplest Z-pinch models for analysis of their experimental results, despite of these models are inconsistent with the MHD equations. In the present study, keeping only the essential terms in the MHD equations, we obtained a simplified MHD model of cylindrically symmetric capillary Z-pinch. The model gives accurate results compared to experiments with argon plasmas, and provides simple analysis of temporal evolution of main plasma parameters. The results clarify the influence of viscosity, heat flux and approximations of plasma conductivity on the dynamics of capillary Z-pinch plasmas. The model can be useful for researchers, especially experimentalists, who develop the soft X-ray/XUV sources. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Pinch-off syndrome: transection of implantable central venous access device

OpenAIRE

Sugimoto, Takuya; Nagata, Hiroshi; Hayashi, Ken; Kano, Nobuyasu

2012-01-01

As the population of people with cancer increases so does the number of patients who take chemotherapy. Majority of them are administered parentally continuously. Implantable central venous catheter device is a good choice for those patients; however, severe complication would occur concerning the devices. Pinch-off syndrome is one of the most severe complications. The authors report a severe case of pinch-off syndrome. The patient with the implantable central venous device could not take che...

Theory of wire number scaling in wire-array Z pinches

International Nuclear Information System (INIS)

Desjarlais, M.P.; Marder, B.M.

1999-01-01

Pulsed-power-driven Z pinches, produced by imploding cylindrical arrays of many wires, have generated very high x-ray radiation powers (>200 TW) and energies (2 MJ). Experiments have revealed a steady improvement in Z-pinch performance with increasing wire number at fixed total mass and array radius. The dominant mechanism acting to limit the performance of these devices is believed to be the Rayleigh-Taylor instability which broadens the radially imploding plasma sheath and consequently reduces the peak radiation power. A model is presented which describes an amplification over the two-dimensional Rayleigh-Taylor growth rate brought about by kink-like forces on the individual wires. This amplification factor goes to zero as the number of wires approaches infinity. This model gives results which are in good agreement with the experimental data and provides a scaling for wire-array Z pinches. copyright 1999 American Institute of Physics

3D modeling of instabilities in multi-wire Z pinches

International Nuclear Information System (INIS)

Haill, T.A.; Desjarlais, M.P.; Marder, B.M.; Robinson, A.C.

1998-01-01

Recent success in generating large x-ray energies and powers from large wire-number Z pinch arrays has revived a strong interest in MHD and magneto-Rayleigh-Taylor (RT) instabilities. Two-dimensional r-z simulations of Z pinches typically start calculations with a preformed plasma sheath and seed RT instabilities with a random density perturbation. The magnitude of the random density perturbation is tuned so that the calculated x-ray radiation pulse matches the amplitude and pulse-width of experimentally measured data. While these calculations have been extremely useful in understanding the effect of RT instabilities on experiments, they do not capture all of the three-dimension structure seen in experimental images and are not truly predictive in nature. To remedy this shortcoming Sandia is developing a 3D nature of Z pinch dynamics, namely the merger of arrays of wires into a plasma sheath

Dynamics of low density coronal plasma in low current x-pinches

International Nuclear Information System (INIS)

Haas, D; Bott, S C; Vikhrev, V; Eshaq, Y; Ueda, U; Zhang, T; Baranova, E; Krasheninnikov, S I; Beg, F N

2007-01-01

Experiments were performed on an x-pinch using a pulsed power current generator capable of producing an 80 kA current with a rise time of 50 ns. Molybdenum wires with and without gold coating were employed to study the effect of high z coating on the low-density ( 18 cm -3 ) coronal plasma dynamics. A comparison of images from XUV frames and optical probing shows that the low density coronal plasma from the wires initially converges at the mid-plane immediately above and below the cross-point. A central jet is formed which moves with a velocity of 6 x 10 4 ms -1 towards both electrodes forming a z-pinch column before the current maximum. A marked change in the low density coronal plasma dynamics was observed when molybdenum wires coated with ∼ 0.09 μm of gold were used. The processes forming the jet structure were delayed relative to bare Mo x-pinches, and the time-resolved x-ray emission also showed differences. An m = 0 instability was observed in the coronal plasma along the x-pinch legs, which were consistent with x-ray PIN diode signals in which x-ray pulses were observed before x-ray spot formation. These early time x-ray pulses were not observed with pure molybdenum x-pinches. These observations indicate that a thin layer of gold coating significantly changes the coronal plasma behaviour. Two dimensional MHD simulations were performed and qualitatively agree with experimental observations of low density coronal plasma

Measurements of hot spots and electron beams in Z-pinch devices

International Nuclear Information System (INIS)

Deeney, C.

1988-04-01

Hot spots and Electron Beams have been observed in different types of Z-pinches. There is, however, no conclusive evidence on how either are formed although there has been much theoretical interest in both these phenomena. In this thesis, nanosecond time resolved and time correlated, X-ray and optical diagnostics, are performed on two different types of Z-pinch: a 4 kJ, 30 kV Gas Puff Z-pinch and a 28 kJ, 60 kV Plasma Focus. The aim being to study hot spots and electron beams, as well as characterise the plasma, two different Z-pinch devices. Computer codes are developed to analyse the energy and time resolved data obtained in this work. These codes model both, X-ray emission from a plasma and X-ray emission due to electron beam bombardment of a metal surface. The hot spot and electron beam parameters are measured, from the time correlated X-ray data using these computer codes. The electron beams and the hot spots are also correlated to the plasma behaviour and to each other. The results from both devices are compared with each other and with the theoretical work on hot spot and electron beam formation. A previously unreported 3-5 keV electron temperature plasma is identified, in the gas puff Z-pinch plasma, prior to the formation of the hot spots. it is shown, therefore, that the hot spots are more dense but not hotter than the surrounding plasma. Two distinct periods of electron beam generation are identified in both devices. (author)

On the dynamics of cylindrical z-pinch

International Nuclear Information System (INIS)

Solov'ev, L.S.

1984-01-01

The stationary configurations of cylindrical plasma flow in the framework of two-liquid relativistic electromagnetic gas dynamics (REMG)) and nonlinear radial oscillations of the plasma cylinder with longitudinal current in the framework of classical monoliquid MGD are considered. It is shown that at sufficiently high conductivity Z-pinch is stable relative to one-dimensional radial perturbations and its motion represents respectively nonlinear radial oscillations. In case of a rather low conductivity or low particle concentration there is in cross section a stability also in relation to the development of sausage type instability. The performed investigations of cylindrical equilibrium and radial oscillations give a qualitative representation on plasma behaviour in Z-pinch at the initial stage of it compression and expansion as well as on motion in an average plane of the developing sausage type instability

Equilibrium and stability MHD in the magnetic confinement for thermonuclear fusion

International Nuclear Information System (INIS)

Otero, Dino; Proto, A.N.

1979-08-01

A survey of the mayor systems for magnetic confinement of plasmas is made. The basic concepts are reviewed briefly. The equilibrium and stability conditions for open systems (mirrors, magnetic wells, Z and Theta-pinches), for toroidal axisymmetric (Z-Pinch, Screw-Pinch, Belt-Pinch and Tokamak) and toroidal non-axisymmetric systems (High-β Stellarator and low-β Theta-Pinch) are discussed. A comparative analysis between the diferent systems is made. In the conclusions, the author's opinions about future developments in the field are included. (author) [es

Earth's radiation belts

International Nuclear Information System (INIS)

Moslehi Fard, M.

1984-01-01

The theory of trapped particles in a magnetic field of approximated dipole is described completely in the first part. Second part contains experimental results. The mechanism of radiation belt source ''albedo neutrons'' and also types of dissipation mechanism about radiation belt is explained. The trapped protons and electrons by radiation belt is discussed and the life-time of trapped particles are presented. Finally the magnetic fields of Moon, Venus, Mars, and Saturn, measured by passengers Mariner 4,10 and pioneer 10,11 are indicated. The experimental and theoretical results for the explanation of trapped plasma around the earth which is looked like two internal and external belt have almost good correspondence

Dynamics Analysis and Modeling of Rubber Belt in Large Mine Belt Conveyors

OpenAIRE

Gao Yang

2014-01-01

Rubber belt not only is one of the key components of belt conveyor, but also affects the overall performance of the core part. Research on dynamics analysis of large conveyor not only helps to improve the reliability and design level, but also can guide the rational selection of conveyor safety factor, and effectively reduce the cost of the conveyor belt. Based on unique viscoelastic properties of belt conveyor, it was simplified as one-dimensional viscoelastic rod in this study, and then a d...

LASL toroidal reversed-field pinch programme

International Nuclear Information System (INIS)

Baker, D.A.; Buchenauer, C.J.; Burkhardt, L.C.

1979-01-01

The determination of the absolute energy loss due to radiation from impurities in the LASL toroidal reversed-field pinch experiment ZT-S is reported. The measurements show that over half the energy loss is accounted for by this mechanism. Thomson-scattering electron density measurements indicate only a gradual increase in temperature as the filling pressure is reduced, indicating an increased energy loss at lower pressures. Cylindrical and toroidal simulations of the experiment indicate either that a highly radiative pinch boundary or anomalous transport is needed to match the experimental results. New effects on the equilibrium due to plasma flows induced by the toroidal geometry are predicted by the toroidal simulations. The preliminary results on the low-temperature discharge cleaning of the ZT-S torus are reported. A description of the upgrade of the ZT-S experiment and the objectives, construction and theoretical predictions for the new ZT-40 experiment are given. (author)

Comparative Studies of Traditional (Non-Energy Integration and Energy Integration of Catalytic Reforming Unit using Pinch Analysis

Directory of Open Access Journals (Sweden)

M. Alta

2012-12-01

Full Text Available Energy Integration of Catalytic Reforming Unit (CRU of Kaduna Refinery and petrochemicals Company Kaduna Nigeria was carried out using Pinch Technology. The pinch analysis was carried out using Maple. Optimum minimum approach temperature of 20 °C was used to determine the energy target. The pinch point temperature was found to be 278 °C. The utilities targets for the minimum approach temperature were found to be 72711839.47 kJ/hr and 87105834.43 kJ/hr for hot and cold utilities respectively. Pinch analysis as an energy integration technique was found to save more energy and utilities cost than the traditional energy technique. Key words: Pinch point, CRU, Energy Target, Maple

Design and experimental research on a self-magnetic pinch diode under MV

Science.gov (United States)

Pengfei, ZHANG; Yang, HU; Jiang, SUN; Yan, SONG; Jianfeng, SUN; Zhiming, YAO; Peitian, CONG; Mengtong, QIU; Aici, QIU

2018-01-01

A self-magnetic pinch diode (SMPD) integrating an anode foil-reinforced electron beam pinch focus and a small high-dose x-ray spot output was designed and optimized. An x-ray focal spot measuring system was developed in accordance with the principle of pinhole imaging. The designed SMPD and the corresponding measuring system were tested under ∼MV, with 1.75 × 2 mm2 oval x-ray spots (AWE defined) and forward directed dose 1.6 rad at 1 m. Results confirmed that the anode foil can significantly strengthen the electron beam pinch focus, and the focal spot measuring system can collect clear focal spot images. This finding indicated that the principle and method are feasible.

Design and experimental research on a self-magnetic pinch diode under MV

Institute of Scientific and Technical Information of China (English)

Pengfei ZHANG; Yang HU; Jiang SUN; Yan SONG; Jianfeng SUN; Zhiming YAO; Peitian CONG; Mengtong QIU; Aici QIU

2018-01-01

A self-magnetic pinch diode (SMPD) integrating an anode foil-reinforced electron beam pinch focus and a small high-dose x-ray spot output was designed and optimized.An x-ray focal spot measuring system was developed in accordance with the principle of pinhole imaging.The designed SMPD and the corresponding measuring system were tested under ～MV,with 1.75 × 2 mm2 oval x-ray spots (AWE defined) and forward directed dose 1.6 rad at 1 m.Results confirmed that the anode foil can significantly strengthen the electron beam pinch focus,and the focal spot measuring system can collect clear focal spot images.This finding indicated that the principle and method are feasible.

Diagnostics for Z-pinch implosion experiments on PTS

Energy Technology Data Exchange (ETDEWEB)

Ren, X. D., E-mail: amosrxd@163.com; Huang, X. B., E-mail: amosrxd@163.com; Zhou, S. T., E-mail: amosrxd@163.com; Zhang, S. Q., E-mail: amosrxd@163.com; Dan, J. K., E-mail: amosrxd@163.com; Li, J., E-mail: amosrxd@163.com; Cai, H. C., E-mail: amosrxd@163.com; Wang, K. L., E-mail: amosrxd@163.com; Ouyang, K., E-mail: amosrxd@163.com; Xu, Q., E-mail: amosrxd@163.com; Duan, S. C., E-mail: amosrxd@163.com; Chen, G. H., E-mail: amosrxd@163.com; Wang, M., E-mail: amosrxd@163.com; Feng, S. P., E-mail: amosrxd@163.com; Yang, L. B., E-mail: amosrxd@163.com; Xie, W. P., E-mail: amosrxd@163.com; Deng, J. J., E-mail: amosrxd@163.com [Key Lab of Pulsed Power, Institute of Fluid Physics, CAEP, P.O. Box 919-108, Mianyang, Sichuan 621999 (China)

2014-12-15

The preliminary experiments of wire array implosion were performed on PTS, a 10 MA z-pinch driver with a 70 ns rise time. A set of diagnostics have been developed and fielded on PTS to study pinch physics and implosion dynamics of wire array. Radiated power measurement for soft x-rays was performed by multichannel filtered x-ray diode array, and flat spectral responses x-ray diode detector. Total x-ray yield was measured by a calibrated, unfiltered nickel bolometer which was also used to obtain pinch power. Multiple time-gated pinhole cameras were used to produce spatial-resolved images of x-ray self-emission from plasmas. Two time-integrated pinhole cameras were used respectively with 20-μm Be filter and with multilayer mirrors to record images produced by >1-keV and 277±5 eV self-emission. An optical streak camera was used to produce radial implosion trajectories, and an x-ray streak camera paired with a horizontal slit was used to record a continuous time-history of emission with one-dimensional spatial resolution. A frequency-doubled Nd:YAG laser (532 nm) was used to produce four frame laser shadowgraph images with 6 ns time interval. We will briefly describe each of these diagnostics and present some typical results from them.

Stabilization of long wavelength sausage and kink modes of a Z-pinch by nonlinear radial oscillations

International Nuclear Information System (INIS)

Bud'ko, A.B.; Karlson, E.T.; Liberman, M.A.

1992-01-01

A number of experiments with fiber-initiated dense Z-pinches, with compressional and gas-embedded Z-pinches, with imploding gas-puff Z-pinches and the straight Extrap configuration performed in the last decade demonstrated sufficiently improved stability of Z-pinch configurations. The striking stability with respect to the sausage modes can be explained, in principle, by ideal MHD theory as well as by finite plasma conductivity effects. The global kink mode can not be stabilized by the appropriate choice of the unperturbed profiles neither within the scope of the ideal MHD nor taking into account finite ion Larmor radius and viscous damping effects. In this report we shall demonstrate that stabilization of the global kink modes can be explained by the assumption that pinch is not in a stationary but in a dynamic equilibrium. (author) 12 refs., 2 figs

Belt conveyor apparatus

Science.gov (United States)

Oakley, David J.; Bogart, Rex L.

1987-01-01

A belt conveyor apparatus according to this invention defines a conveyance path including a first pulley and at least a second pulley. An endless belt member is adapted for continuous travel about the pulleys and comprises a lower portion which engages the pulleys and an integral upper portion adapted to receive objects therein at a first location on said conveyance path and transport the objects to a second location for discharge. The upper belt portion includes an opposed pair of longitudinally disposed crest-like members, biased towards each other in a substantially abutting relationship. The crest-like members define therebetween a continuous, normally biased closed, channel along the upper belt portion. Means are disposed at the first and second locations and operatively associated with the belt member for urging the normally biased together crest-like members apart in order to provide access to the continuous channel whereby objects can be received into, or discharged from the channel. Motors are in communication with the conveyance path for effecting the travel of the endless belt member about the conveyance path. The conveyance path can be configured to include travel through two or more elevations and one or more directional changes in order to convey objects above, below and/or around existing structures.

Fiber Z-pinch experiments and calculations in the finite Larmor radius regime

International Nuclear Information System (INIS)

Haines, M.G.; Dangor, A.E.; Coppins, M.

1996-01-01

The dense Z-pinch project at Imperial College is aimed at achieving radiative collapse to high density in a hydrogen plasma, and also to study plasmas close to controlled fusion conditions. To this end, the MAGPIE generator (2.4 MV, 1.25 Ω, and 200 ns) has been built and tested, and is now giving preliminary experimental data at 60% of full voltage for carbon and CD 2 fibers. These discharges are characterized by an initial radial expansion followed by the occurrence of m = 0 structures with transient X-ray emission from bright spots. Late in the discharge a disruption can occur, accompanied by hard X-ray emission from the anode due to an energetic electron beam and, in the case of CD 2 fibers, a neutron burst. Concomitant theoretical studies have solved the linear stability problem for a Z-pinch with large ion Larmor radii, showing that a reduction in growth rate of m = 0 and m = 1 modes to about 20% of the magnetohydrodynamic (MHD) value can occur for a parabolic density profile when the Larmor radius is optimally 20% of the pinch radius. Two-dimensional MHD simulations of Z-pinches in two extremes of focussed short-pulse laser-plasma interactions and of galactic jets reveal a nonlinear stabilizing effect in the presence of sheared flow. One-dimensional simulations show that at low line density the lower hybrid drift instability can lead to coronal radial expansion of a Z-pinch plasma. (Author)

Progress in Z-pinch research driven by the mega-ampere device SPEED2

International Nuclear Information System (INIS)

Pavez, Cristian; Soto, Leopoldo; Moreno, Jose; Sylvester, Gustavo; Tarifeno, Ariel

2008-01-01

Several pinch configurations have being studied at the Chilean Nuclear Energy Commission using the SPEED2 generator: plasma focus, gas embedded z-pinch and wire arrays. SPEED2 is a generator based on Marx technology (4.1 μF equivalent Marx generator capacity, 300 kV, 4 MA in short circuit, 187 kJ, 400 ns rise time, dI/dt∼10 13 A/s). Currently the device is being operated at 70kJ stored energy producing a peak current of 2.4 MA in short circuit. In this work results related to studies in gas embedded z-pinch in deuterium and studies in wire arrays are presented.

Progress in Z-pinch research driven by the mega-ampere device SPEED2

International Nuclear Information System (INIS)

Pavez, Cristian; Soto, Leopoldo; Moreno, Jose; Tarifeno, Ariel; Sylvester, Gustavo

2008-01-01

Several pinch configurations have being studied at the Chilean Nuclear Energy Commission using the SPEED2 generator: plasma focus, gas embedded z-pinch and wire arrays. SPEED2 is a generator based on Marx technology (4.1 μF equivalent Marx generator capacity, 300 kV, 4 MA in short circuit, 187 kJ, 400 ns rise time, dI/dt∼10 13 A/s). Currently the device is being operated at 70kJ stored energy producing a peak current of 2.4 MA in short circuit. In this work results related to studies in gas embedded z-pinch in deuterium and studies in wire arrays are presented

Study of X-ray emission in aluminium z-pinches

International Nuclear Information System (INIS)

Rosch, R.

1999-01-01

Previous experiments, at 0.1. TX level, have shown that stability and x-ray emission of fast Z-pinches, could be strongly increased by imploding an aluminium vapor jet onto a very thin coaxial wire. We present here first results of an aluminium Z-pinch, using a similar liner, but at mega-ampere level. The pinch is driven by AMBIORIX high-power facility, a 2 TW, 0.5 Ω, 2 MA, 50 ns pulse-line generator. We study the effect of an aluminium wire and its diameter (20-50 μm) on the implosion dynamics, on x-ray yield on MHD stability of the column at stagnation. Analysis of A1 jet on A1 wire shots demonstrates that x-ray yield due to emission processes in the H- and He- like ionization stages (i.e. the K-shell) is significantly enhanced, relative to that of A1 jet only ones. The wire also leads to better symmetry of the implosion, and to better reproducibility of shots. X-ray signals exhibit two similar pulses, 10 ns in width, 15 ns spaced. To discern spectral origin of both pulses, experiments are realized with stainless steel wire (25 μm in diameter). Results show that liner and wire radial simultaneously and contribute to both pulses. Analysis of a typical A1 jet on A1 wire shot, using detailed collisional-radiative equilibrium (CRE) model is also given in this thesis. View o the pinch at stagnation as a cola-dense core surrounded by a hot-low density corona reproduces all features of the X-ray data. (author)

On the equilibrium of a linear Extrap pinch

International Nuclear Information System (INIS)

Lehnert, B.

1982-01-01

The equilibrium is studied of a pinched linear plasma column of 'Extrap' type which is confined in a purely transverse magnetic field, partly arising from currents in a set of external conductor rods being introduced for stabilizing purposes. The axial and transverse losses are separated in a simplified theoretical model for which stability is assumed as a working hypothesis and anomalous transport as well as impurity radiation are neglected. Then, the reduction of the axial heat transport by the magnetic field will have a substantial effect on the over-all heat balance, thus leading to high temperatures at large axial lengths of the plasma column. Conditions near ignition should become possible at technically realistic linear dimensions and pinch currents. (orig.)

Pinch Related Research At Institute For Plasma Research, India

International Nuclear Information System (INIS)

Shyam, Anurag

2006-01-01

Several pinch related experiment, their drivers and related diagnostics are being developed in our laboratory. The first set of experiments is to investigate various aspects of magnetized target fusion (MTF/MAGO). To drive the liner, in Z or theta pinch configuration, a 1.2 MJ, 3.6 MA capacitor bank is developed. For liner diagnostics flash radiography, VISAR and pyrometery are being developed. To produce magnetized (target) plasma a 120 kJ, 3 MA and several other banks are developed. Hot magnetized Plasma will be diagnosed by optical schlieren, interferometery and X-Ray spectrometry. A terra-watt system consisting of a Marx bank and water line delivering 800 kA at 1.6 MV will be commissioned, soon. The device will be used to study different pinch (wire array) configurations for production of electro-magnetic radiations. Smaller pulsed power systems, consisting of 1MV/500 kV Marx bank/tesla transformer and than water or solid state (cables) pulse forming network (coax) are also being developed for capillary discharge and other experiments. Two plasma foci experiments are also being conducted. The effort is produce a repetitively operating compact plasma focus

Analysis of stress distribution of timing belts by FEM; Yugen yosoho ni yoru timing belt oryoku kaiseki (belt code oryoku bunpu kaiseki hokoku)

Energy Technology Data Exchange (ETDEWEB)

Furukawa, Y; Tomono, K; Takahashi, H; Uchida, T [Honda R and D Co. Ltd., Tokyo (Japan)

1997-10-01

A model of the belt analyzed by-ABAQUS (: a general nonlinear finite element program) successfully confirmed the mechanism that generates the belt cord stress. A quite good agreement between experimental and computed results for the stress distribution of the belt cord. It is found that maximum stress of the cords occurs near the root of the tooth by calculation, where the belt cords break off. 3 refs., 9 figs.

Experimental studies of the MHD stability of non-circular Extrap Z-pinches

International Nuclear Information System (INIS)

Drake, J.R.

1985-01-01

Extrap Z-pinches, which can be sustained for many Alfven times, can be characterized as non-circular Z-pinch discharges bounded by a magnetic separatrix acting somewhat like a limiter. The magnetic separatrix is produced when a vacuum magnetic field, generated by currents in external conductors, combines with the self-magnetic field produced by the discharge current. The separatrix deforms the pinch cross-section and affects the equilibrium at the pinch boundary; both effects improve stability. Experiments have been performed which indicate that both effects are necessary for the successful generation of sustained Extrap discharges. In one experiment, the importance of the non-circularity of the cross-section was investigated. The deformation provided by the vacuum field can provide regions in the discharge where field lines have good curvature, which improves the stability of the configuration against internal modes. In configurations apparently lacking good curvature, discharges could not be sustained. In a second experiment, the dependence of the amplitude of global kink instabilities on the discharge current density profile were studied. The behaviour of the modes was consistent with that which would be expected for surface current-driven modes. (orig.)

Experimental studies of the MHD stability of non-circular extrap Z-pinches

International Nuclear Information System (INIS)

Drake, J.R.

1984-12-01

Extrap Z-pinches, which can be sustained for many Alfven times, can be characterized as non-circular Z-pinch discharges bounded by a magnetic separatrix acting somewhat like a limiter. The magnetic separatrix is produced when a vacuum magnetic field, generated by currents in external conductors, combines with the self-magnetic field produced by the discharge current. The separatrix deforms the pinch cross-section and affects the equilibrium at the pinch boundary; both effects improve stability. Experiments have been performed which indicate that both effects are necessary for the successful generation of sustained Extrap discharges. In one experiment, the importance of the non-circularity of the cross-section was investigated. The deformation provided by the vacuum field can provide regions in the discharge where field lines have good curvature, which improves the stability of the configuration against internal modes. In configurations apparently lacking good curvature, discharges could not be sustained. In a second experiment, the dependence of the amplitude of global kink instabilities on the discharge current density profile were studied. The behaviour of the modes was consistent with that which would be expected for surface current-driven modes. (Author)

A heuristic model of the wire array z-pinch

International Nuclear Information System (INIS)

Haines, M.G.

1998-01-01

Recent experimental results at the Sandia National Laboratory have shown that the X-ray power increases as the number of wires n employed is increased, with a sharper increase in power when the wire gap is below a critical value. This paper proposes a model that can not only explain these phenomena, but also shows how the initial perturbations that lead to the Rayleigh-Taylor instability scale as n -1/2 . The model predicts the shell thickness at merger of the expanding separate wires which will mainly determine the final pinch radius. The largest amplitude Rayleigh-Taylor mode at the pinch time is also found, in reasonable agreement with experiment

Explosive instabilities of reaction-diffusion equations including pinch effects

International Nuclear Information System (INIS)

Wilhelmsson, H.

1992-01-01

Particular solutions of reaction-diffusion equations for temperature are obtained for explosively unstable situations. As a result of the interplay between inertial, diffusion, pinch and source processes certain 'bell-shaped' distributions may grow explosively in time with preserved shape of the spatial distribution. The effect of the pinch, which requires a density inhomogeneity, is found to diminish the effect of diffusion, or inversely to support the inertial and source processes in creating the explosion. The results may be described in terms of elliptic integrals or. more simply, by means of expansions in the spatial coordinate. An application is the temperature evolution of a burning fusion plasma. (au) (18 refs.)

Study of X-ray emission in aluminium z-pinches; Etude de l'emission X dans les plasmas d'aluminium de type Z-pinch

Energy Technology Data Exchange (ETDEWEB)

Rosch, R [CEA/DAM-Ile de France, Dept. de Conception et Realisation des Experimentations (DCRE), 91 - Bruyeres-le-Chatel (France); [Paris-11 Univ., 91 - Orsay (France)

1999-07-01

Previous experiments, at 0.1. TX level, have shown that stability and x-ray emission of fast Z-pinches, could be strongly increased by imploding an aluminium vapor jet onto a very thin coaxial wire. We present here first results of an aluminium Z-pinch, using a similar liner, but at mega-ampere level. The pinch is driven by AMBIORIX high-power facility, a 2 TW,0.5 {omega}, 2 MA, 50 ns pulse-line generator. We study the effect of an aluminium wire and its diameter (20-50 {mu}m) on the implosion dynamics, on x-ray yield on MHD stability of the column at stagnation. Analysis of A1 jet on A1 wire shots demonstrates that x-ray yield due to emission processes in the H- and He- like ionization stages (i.e. the K-shell) is significantly enhanced, relative to that of A1 jet only ones. The wire also leads to better symmetry of the implosion, and to better reproducibility of shots. X-ray signals exhibit two similar pulses, 10 ns in width, 15 ns spaced. To discern spectral origin of both pulses, experiments are realized with stainless steel wire (25 {mu}m in diameter). Results show that liner and wire radial simultaneously and contribute to both pulses. Analysis of a typical A1 jet on A1 wire shot, using detailed collisional-radiative equilibrium (CRE) model is also given in this thesis. View o the pinch at stagnation as a cola-dense core surrounded by a hot-low density corona reproduces all features of the X-ray data. (author)

DT ignition in a Z pinch compressed by an imploding liner

International Nuclear Information System (INIS)

Bilbao, L.; Bernal, L.; Linhart, J.G.; Verri, G.

2001-01-01

It has been shown that an m=0 instability of a Z pinch carrying a current of the order of 10 MA with a rise time of less than 10 ns can generate a spark capable of igniting a fusion detonation in the adjacent DT plasma channel. A possible method for generating such currents, necessary for the implosion of an initial large radius, low temperature Z pinch, can be a radial implosion of a cylindrical fast liner. The problem has been addressed in previous publications without considering the role played by an initially impressed m=0 perturbation, a mechanism indispensable for the generation of a spark. The liner-Z pinch dynamics can be solved at several levels of physical model completeness. The first corresponds to a zero dimensional model in which the liner has a given mass per unit length and a zero thickness, the plasma is compressed adiabatically and is isotropic, and there are no energy losses or Joule heating. The second level is one dimensional. The Z pinch plasma is described by the full set of MHD, two-fluid equations. The liner is treated first as thin and incompressible, and subsequently it is assumed that it has a finite thickness and is composed of a heavy ion plasma, having an artificial but realistic equation of state. Both plasma and liner are considered uniform in the Z direction and only DT reactions are considered. It is shown that, given sufficient energy and speed of the liner, the Z pinch can reach a volume ignition. The third level is two dimensional. Plasma and liner are treated as in the second level but either the Z pinch or the liner is perturbed by an m=0 non-uniformity. Provided the liner energy is high enough and the initial m=0 perturbation is correctly chosen, the final neck plasma can act as a spark for DT ignition. It is also shown that the liner energy required for generating a spark and the subsequent detonation propagation are considerably less than in the case of volume ignition. (author)

Development of fast pulsed power driver for radiography and Z-pinch

International Nuclear Information System (INIS)

Qiu Aici; Sun Fengju

2008-01-01

Z-pinch and flash X-ray radiography have an important application in inertial confine fusion (ICF) and nuclear radiation effects simulation and high performance hydrodynamic test, etc. Z-pinch ICF and multi-pulse multi-axis high energy X-ray radiography put forward a huge challenge for pulsed power driver, so the direct-driven-load fast pulsed power driver are developed actively in home and abroard. The paper summarized the recent advances and developing trends of the fast pulsed power driver based on fast Marx(FMG) and fast linear transformer driver (LTD), and analysized the advantages and disadvantages and restricting factors about FMG and FLTD and their key technologies, then introduced the state-of-arts on the investigation in Northwest Institute of Nuclear Technology. In the end, the paper presented some advices and views about studying fast pulsed power driver applied to Z-pinch and flash X-ray radiography in home. (authors)

Observation of helical structure in a low energy plasma focus pinch

International Nuclear Information System (INIS)

Rout, R.K.; Shyam, A.

1989-01-01

Helical structure and hot spots were observed in a Mather-type plasma focus operated at 3 KJ of bank energy. The experiments were carried out with the help of a fast optical framing camera and two X-ray pin-hole cameras with different filters. It was observed that initially a conical pinch (with base diameter of 6 mm and length of 14 mm) with temperature of ≅ 10 2 eV was formed. This pinch disintegrated after ≅ 50 ns by a single lobe sausage instability into a central high temperature (≅ 10 3 eV) filament of 1 mm diameter and 8 mm length containing a high emissivity helical structure. This helix is probably responsible for generation of axial magnetic field and relaxation of the focus pinch. Hot spots of high X-ray intensity and temperature (≅ 10 3 eV) were also observed much beyond the filament region. (author)

X pinch a point x-ray source

International Nuclear Information System (INIS)

Garg, A.B.; Rout, R.K.; Shyam, A.; Srinivasan, M.

1993-01-01

X ray emission from an X pinch, a point x-ray source has been studied using a pin-hole camera by a 30 kV, 7.2 μ F capacitor bank. The wires of different material like W, Mo, Cu, S.S.(stainless steel) and Ti were used. Molybdenum pinch gives the most intense x-rays and stainless steel gives the minimum intensity x-rays for same bank energy (∼ 3.2 kJ). Point x-ray source of size (≤ 0.5 mm) was observed using pin hole camera. The size of the source is limited by the size of the pin hole camera. The peak current in the load is approximately 150 kA. The point x-ray source could be useful in many fields like micro lithography, medicine and to study the basic physics of high Z plasmas. (author). 4 refs., 3 figs

Energy transformation in Z-pinch and plasma focus discharges with wire and wire-in-liner loads

International Nuclear Information System (INIS)

Kubes, Pavel; Kravarik, Jozef; Klir, Daniel; Scholz, Marek; Paduch, Marian; Tomaszewski, Krzysztof; Karpinski, Leslaw; Bakshaev, Yury L.; Blinov, Peter I.; Chernenko, Andrey S.; Dan'ko, Sergey A.; Korolev, Valery D.; Shashkov, Andrey Y.; Tumanov, Victor I.

2002-01-01

The results of the study of the Z-pinch and plasma-focus plasmas at presence of the axial C, Al, or Cu wires of sufficient high diameter are discussed in this paper. The wire was positioned on the top of the inner electrode of the PF 1000 plasma focus (1.8 MA, IPPLM Warsaw), or at the axis with or without the tungsten or alumine wire array load at the S-300 facility (3 MA, RRC Kurchatov Institute, Moscow), and at the axis of the small Z-pinch Z-150 (50 kA, CTU Prague). The plasma corona around the wire was generated both by the current going through the wires and by the implosion of the wire array or of the current sheath. The experiments showed interesting results often observed in some shots of Z-pinch type discharges - existence of helical structures, two relatively long and stable pinch phases, oscillation of pinch diameter, and back return of the plasma exploding from the pinch. All these observed phenomena can be evolved by spontaneous self-generation and transformation of the axial magnetic field in the pinch during the plasma implosion and explosion. A configuration of axial and azimuthal magnetic field confines the plasma and later transforms or dissipates during a few tens or hundreds ns. A fast transformation of internal magnetic fields can induce a sufficiently high electric field for generation of keV particles and radiation. Study and usage of Z-pinch discharges is connected with solving of two principal problems, limitation of instability development and a way of generation of high energy particles and radiation. The first problem is partially solved by the faster increase of the current, by better cylindrical symmetry of the load and plasma, by higher density of the plasma or by the presence of a stronger magnetized plasma

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

International Nuclear Information System (INIS)

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

2007-01-01

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

Equilibrium, stability and heating of plasmas in linear and toroidal Extrap pinches

International Nuclear Information System (INIS)

Bonnevier, B.; Drake, J.R.; Dalhed, H.E.

1983-01-01

The Extrap scheme consists of a Z-pinch immersed in an octupole field. The total magnetic field has no component along the pinch axis. Globally stable Z-pinch equilibria with a distributed plasma current density and a duration of about 100 Alfven transit times have been observed in linear and toroidal sector experiments. Theoretical studies indicate that this stability can be the result of constraints introduced by the octupole field and the resulting separatrix of the total field, in combination with finite-Larmor-radius effects. A scheme for ICRF heating of the plasma in configurations with a magnetic neutral line, being applicable to Extrap and FRC, is analysed. Wave propagation arises owing to the Hall effect. Particle resonances are responsible for the absorption, owing to a high parallel wavenumber and a weak magnetic field. (author)

The stability of Z-pinches with equilibrium flows

International Nuclear Information System (INIS)

Howell, D.F.

1999-01-01

According to Ideal Magnetohydrodynamic (MHD) theory the Z-pinch is an inherently unstable magnetic configuration. However it is possible that there exist regimes of operation whereby the predicted instabilities may be reduced or even eliminated. We must look to effects normally ignored in the Ideal MHD model in order to predict such regimes. In this thesis various non-ideal effects will be studied, namely the inclusion of equilibrium flow and finite Larmor radius effects. Astrophysical jets, for example those seen to be emitted from active galactic nuclei, are seen to persist for a greater time than suggested by Ideal MHD before the onset of instabilities. It is postulated that one of the contributing factors to this enhanced stability is the presence of a sheared axial flow. In this thesis we study the stability properties of the Z-pinch where flow is present in the equilibrium. It is found that a sheared axial flow generally has a stabilising effect, the degree of which is determined by the equilibrium and flow profiles, but that absolute stability cannot be achieved due to the onset of the Kelvin-Helmholtz instability. The effect of adding rotation has also been studied. It is found that adding rotation changes the equilibrium density profiles from the static case, and that it always has a destabilising effect. Another postulated method of stabilising the Z-pinch is by increasing the ratio of the ion Larmor radius to the pinch radius, and it is seen to have a stabilising effect for some equilibria in the collisionless regime. In this thesis we study the effects of increasing the Larmor radius in the collisional regime using the Hall fluid model. It is found that for free boundary modes the stability properties are unchanged for experimentally realistic values of the Larmor radius, but for fixed boundary modes a small stabilising effect is noted for some equilibria. (author)

Stabilization of sausage and kink instability modes of a plasma pinch by radial oscillations

International Nuclear Information System (INIS)

Bud'ko, A.B.; Kravchenko, Y.P.; Liberman, M.A.

1995-01-01

The growth of the global sausage (m=0) and kink (m=1) perturbations of a Z-pinch subject to radial oscillations is considered. It is demonstrated that the oscillations result in significant reduction of the growth rate of both kink and sausage instability modes with wavelengths long compared to the pinch radius. The analysis of stability is carried out in two ways. The first method is based on the averaging magnetohydrodynamic equations over the period of radial oscillations. The second one consists in the analysis of the growth of Fourier-components of perturbations. Numerical simulation demonstrates that even moderate radial oscillations cause reduction of the growth rate of long-wavelength sausage instabilities and complete stabilization of long kinks. This can be understood as a result of the effective gravitational field produced in the pinch by the oscillations. The effect in question can explain the anomalous stability of pinches with respect to the kink perturbations observed in experiments. copyright 1995 American Institute of Physics

Study of energy transfer in table-top X-pinch driven by a water line

International Nuclear Information System (INIS)

Beg, F N; Zhang, T; Fedin, D; Beagen, B; Chua, E; Lee, J Y; Rawat, R S; Lee, P

2007-01-01

The current passing through X-pinches and the energy transferring from the pulse forming line to the load are modelled using a simple LCR circuit. A comparison of the electrical properties of two table-top X-pinch devices is made. It was found that up to 25% of the stored energy is transferred from the water transmission line to the load in the University of California,San Diego (UCSD) table-top X-pinch before x-ray emission starts. The highest energy transmitted (75%) is found after the current peak. In comparison, only 3% of the energy is transferred to the load in the National Institute of Education (NIE) X-pinch device just after the maximum current peak. The highest energy (25%) transmitted to the plasma occurs long after the current peak. The plasma in both devices is visually and qualitatively similar. However, the UCSD device emits intense x-rays with no x-rays observed in the NIE device. This observation is consistent with the electrical circuit analysis

A spin-liquid with pinch-line singularities on the pyrochlore lattice.

Science.gov (United States)

Benton, Owen; Jaubert, L D C; Yan, Han; Shannon, Nic

2016-05-26

The mathematics of gauge theories lies behind many of the most profound advances in physics in the past 200 years, from Maxwell's theory of electromagnetism to Einstein's theory of general relativity. More recently it has become clear that gauge theories also emerge in condensed matter, a prime example being the spin-ice materials which host an emergent electromagnetic gauge field. In spin-ice, the underlying gauge structure is revealed by the presence of pinch-point singularities in neutron-scattering measurements. Here we report the discovery of a spin-liquid where the low-temperature physics is naturally described by the fluctuations of a tensor field with a continuous gauge freedom. This gauge structure underpins an unusual form of spin correlations, giving rise to pinch-line singularities: line-like analogues of the pinch points observed in spin-ice. Remarkably, these features may already have been observed in the pyrochlore material Tb2Ti2O7.

Reversed-field pinch configuration with minimum energy and finite beta

International Nuclear Information System (INIS)

Zhang Peng

1989-01-01

The reversed-field pinch (RFP) configuration has been studied for the case of finite beta. Suydam's condition and the sufficient criterion have been used to examine this configuration. Results of numerical calculations show that the critical value of the pinch parameter Θ for the appearance of the reverse toroidal field increases as the β-value increases. The critical value of Θ for the helical state increases with β as well. Suydam's and Robinson's stability regions increase and shift towards higher values of Θ with increasing β. Theoretical results for finite β coincide with recent RFP experimental results

The effect of magnetic field configuration on particle pinch velocity in compact helical system (CHS)

International Nuclear Information System (INIS)

Iguchi, H.; Ida, K.; Yamada, H.

1994-01-01

Radial particle transport has been experimentally studied in the low-aspect-ratio heliotron/torsatron device CHS. A non-diffusive outward particle flow (inverse pinch) is observed in the magnetic configuration with the magnetic axis shifted outward, while an inward pinch, like in tokamaks, is observed with the magnetic axis shifted inward. This change in the direction of anomalous particle flow is not due to the reversal of temperature gradient nor the radial electric field. The observation suggests that the particle pinch velocity is sensitive to the magnetic field structure. (author)

Los Alamos Compact Toroid, fast liner, and High-Density Z-Pinch programs

International Nuclear Information System (INIS)

Linford, R.K.; Hammel, J.E.; Sherwood, H.R.

1982-01-01

The compact Toroid and High Density Z-Pinch are two of the plasma configurations presently being studied at Los Alamos. This paper summarizes these two programs along with the recently terminated Fast Liner Program. Included in this discussion is an analysis of compact Toroid formation techniques showing the tearing and reconnection of the fields that separate the spheromak from the radial fields of the coaxial source, and the final equilibrium state of the elongated FRC in the theta-pinch coil. In addition the typical dimensions of the geometry of the Fast Liner experiments are delineated Z-pinch and electrode assembly is displayed as is a graphic of the temporal behavior of the current required for radial equilibrium. Spheromak is examined in terms of formation, gross stability, and equilibrium and field reversed configuration is discussed in terms of gross stability, equilibrium, and confinement scaling

Interferometric characterization of density dynamics of an ultradense Z-pinch plasma

International Nuclear Information System (INIS)

Ackenhusen, J.G.; Bach, D.R.

1979-01-01

We have measured the spatially and temporally resolved density in a Z-pinch plasma by holographic interferometry. The high electron density (4 x 10 19 e/cm 3 ), short density scale length (100 μm), and low temperature (about 20 eV) make the plasma source suitable for simulation of laser-pellet interaction experiments at 10.6-μm laser wavelengths. A cinema of density evolution, indicating plasma pinching and subsequent relaxation, provides an experimental view of plasma dynamics which is then compared to simple theoretical models

A study of Z-pinch in capillary filled by boron vapours

Czech Academy of Sciences Publication Activity Database

Vrba, Pavel; Vrbová, M.; Bobrova, N. A.; Sasorov, P. V.

2009-01-01

Roč. 51, č. 2 (2009), s. 481-486 ISSN 1434-6079. [Symposium on Plasma Physics and Technology/23rd./. Praha, 16.06.2008-19.06.2008] R&D Projects: GA ČR GA102/07/0275; GA MŠk LA08024 Institutional research plan: CEZ:AV0Z20430508 Keywords : Z-pinches * plasma focus and other pinch devices * Plasma devices for generation of coherent radiation * Magnetohydrodynamics and fluid equation Subject RIV: BH - Optics, Masers, Lasers www.edpsciences.org/epjd nebo www.epj.org

Belt drive construction improvement

Directory of Open Access Journals (Sweden)

I.Yu. Khomenko

2012-08-01

Full Text Available The possibility of the traction capacity increase of the belt drive TRK is examined. This was done for the purpose of air conditioning system of passenger car with double-generator system energy supplying. Belts XPC (made by the German firm «Continental ContiTech» testing were conducted. The results confirmed the possibility of their usage in order to improve belt drive TRK characteristics.

Quantification of hand function by power grip and pinch strength force measurements in ulnar nerve lesion simulated by ulnar nerve block.

Science.gov (United States)

Wachter, Nikolaus Johannes; Mentzel, Martin; Krischak, Gert D; Gülke, Joachim

2017-06-24

In the assessment of hand and upper limb function, grip strength is of the major importance. The measurement by dynamometers has been established. In this study, the effect of a simulated ulnar nerve lesion on different grip force measurements was evaluated. In 25 healthy volunteers, grip force measurement was done by the JAMAR dynamometer (Fabrication Enterprises Inc, Irvington, NY) for power grip and by a pinch strength dynamometer for tip pinch strength, tripod grip, and key pinch strength. A within-subject research design was used in this prospective study. Each subject served as the control by preinjection measurements of grip and pinch strength. Subsequent measurements after ulnar nerve block were used to examine within-subject change. In power grip, there was a significant reduction of maximum grip force of 26.9% with ulnar nerve block compared with grip force without block (P force could be confirmed. However, the assessment of other dimensions of hand strength as tip pinch, tripod pinch and key pinch had more relevance in demonstrating hand strength changes resulting from an distal ulnar nerve lesion. The measurement of tip pinch, tripod grip and key pinch can improve the follow-up in hand rehabilitation. II. Copyright © 2017 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.

Scintillator power meter applied on Z-pinch plasma soft X-ray yield measurement

International Nuclear Information System (INIS)

Zhang Siqun; Huang Xianbin; Li Jing; Dan Jiakun; Li Jun; Yang Libing; Cui Mingqi; Zhao Yidong

2010-01-01

This paper presents the configuration and measuring parameters of scintillator power meter applied in Z-pinch plasma soft X-ray yield measurement on Yang accelerator. It also introduces the calibration experiment on BSRF, and analyzes the defect of the power meter from calibration results, the possible errors and feasible method for correcting the errors. The measuring results are revised according to spectrum acquired from Dante spectrometer. The revised discrepancy of two instruments is decreased from over 30% to subter-15%. Finally, the result of yield measurement of the puff Z-pinch X-ray radiation is reported as well, i.e., hundreds of Joule, multigigawatt levels of soft X ray radiation were produced by puff Z-pinch on Yang accelerator. (authors)

Continuous Mass Measurement on Conveyor Belt

Science.gov (United States)

Tomobe, Yuki; Tasaki, Ryosuke; Yamazaki, Takanori; Ohnishi, Hideo; Kobayashi, Masaaki; Kurosu, Shigeru

The continuous mass measurement of packages on a conveyor belt will become greatly important. In the mass measurement, the sequence of products is generally random. An interesting possibility of raising throughput of the conveyor line without increasing the conveyor belt speed is offered by the use of two or three conveyor belt scales (called a multi-stage conveyor belt scale). The multi-stage conveyor belt scale can be created which will adjust the conveyor belt length to the product length. The conveyor belt scale usually has maximum capacities of less than 80kg and 140cm, and achieves measuring rates of more than 150 packages per minute and more. The output signals from the conveyor belt scale are always contaminated with noises due to vibrations of the conveyor and the product to be measured in motion. In this paper an employed digital filter is of Finite Impulse Response (FIR) type designed under the consideration on the dynamics of the conveyor system. The experimental results on the conveyor belt scale suggest that the filtering algorithms are effective enough to practical applications to some extent.

PINCH1 regulates cell-matrix and cell-cell adhesions, cell polarity and cell survival during the peri-implantation stage

DEFF Research Database (Denmark)

Li, Shaohua; Bordoy, Randi; Stanchi, Fabio

2005-01-01

PINCH1 is composed of 5 LIM domains, binds integrin-linked kinase (ILK) and locates to integrin-mediated adhesion sites. In order to investigate PINCH1 function we generated mice and embryonic stem (ES) cell-derived embryoid bodies (EBs) lacking the PINCH1 gene. Similar to mice lacking beta1...... integrin or Ilk, loss of PINCH1 arrested development at the peri-implantation stage. In contrast to beta1 integrin or Ilk mutants, however, disruption of the PINCH1 gene produced implantation chambers with visible cell clumps even at embryonic day 9.5. In order to define the phenotype leading to the peri...... not observed in beta1 integrin- or ILK-deficient mice or EBs, included abnormal cell-cell adhesion of endoderm and epiblast as well as the presence of apoptotic cells in the endodermal cell layer. Although ILK and PINCH1 were shown to be involved in the phosphorylation of serine-473 of PKB/Akt, immunostaining...

The TITAN reversed-field-pinch fusion reactor study

International Nuclear Information System (INIS)

1990-01-01

This paper on titan plasma engineering contains papers on the following topics: reversed-field pinch as a fusion reactor; parametric systems studies; magnetics; burning-plasma simulations; plasma transient operations; current drive; and physics issues for compact RFP reactors

Equilibria and Free Vibration of a Two-Pulley Belt-Driven System with Belt Bending Stiffness

Directory of Open Access Journals (Sweden)

Jieyu Ding

2014-01-01

Full Text Available Nonlinear equilibrium curvatures and free vibration characteristics of a two-pulley belt-driven system with belt bending stiffness and a one-way clutch are investigated. With nonlinear dynamical tension, the transverse vibrations of the translating belt spans and the rotation motions of the pulleys and the accessory shaft are coupled. Therefore, nonlinear piecewise discrete-continuous governing equations are established. Considering the bending stiffness of the translating belt spans, the belt spans are modeled as axially moving beams. The pattern of equilibria is a nontrivial solution. Furthermore, the nontrivial equilibriums of the dynamical system are numerically determined by using two different approaches. The governing equations of the vibration near the equilibrium solutions are derived by introducing a coordinate transform. The natural frequencies of the dynamical systems are studied by using the Galerkin method with various truncations and the differential and integral quadrature methods. Moreover, the convergence of the Galerkin truncation is investigated. Numerical results reveal that the study needs 16 terms after truncation in order to determine the free vibration characteristics of the pulley-belt system with the belt bending stiffness. Furthermore, the first five natural frequencies are very sensitive to the bending stiffness of the translating belt.

Dynamics Analysis and Modeling of Rubber Belt in Large Mine Belt Conveyors

Directory of Open Access Journals (Sweden)

Gao Yang

2014-10-01

Full Text Available Rubber belt not only is one of the key components of belt conveyor, but also affects the overall performance of the core part. Research on dynamics analysis of large conveyor not only helps to improve the reliability and design level, but also can guide the rational selection of conveyor safety factor, and effectively reduce the cost of the conveyor belt. Based on unique viscoelastic properties of belt conveyor, it was simplified as one-dimensional viscoelastic rod in this study, and then a discrete element model of conveyor systems was established. The kinetic equations of each discrete unit was derived using kinetic energy, potential energy of driving segment, bearing segment and return segment and equation of energy dissipation and Lagrange equation. Based on Wilson-q algorithm, the kinetic equation of DT1307-type ST2000's conveyor belt was solved by using Matlab to write computer programs. Research on the change rule of conveyor displacement, velocity, acceleration and dynamic tension during the boot process revealed the working mechanism of nonlinear viscoelastic, which lay the theoretical foundation for dynamic performance optimization of large belt conveyor. The calculation results were used to optimize design and analysis of conveyor system, the result showed that it could reduce the driven tension peaks about 12 %, save 5 % of overall manufacturing cost, which bring considerable profits for enterprises.

Dense X-pinch plasmas for x-ray microlithography

International Nuclear Information System (INIS)

Kalantar, D.H.; Hammer, D.A.; Qi, N.; Mittal, K.C.

1990-01-01

The authors report experimental results from a study of the radiation emission from aluminum and magnesium x-pinch experiments. The single cross x-pinch, driven by the 0.5 TW, 40ns pulse width Lion accelerator, consists of 2-8 fine wires stretched between the output electrodes of Lion so as to touch at a single point. The wires were twisted up to 360 degrees at the crossing point. The number and size of Al and Mg wires were varied in order to optimize the K-shell line radiation. Diagnostics used for the experiments included pinhole photography, streak imaging, filtered photoconducting diodes and x-ray crystal spectroscopy. The source size and distribution are determined through x-ray pinhole photographs. The radiation energy spectrum is determined by x-ray spectroscopy and attenuation through filters. Energy intensities were obtained from the filtered photoconducting diodes

Eigenvalue pinching on spinc manifolds

Science.gov (United States)

Roos, Saskia

2017-02-01

We derive various pinching results for small Dirac eigenvalues using the classification of spinc and spin manifolds admitting nontrivial Killing spinors. For this, we introduce a notion of convergence for spinc manifolds which involves a general study on convergence of Riemannian manifolds with a principal S1-bundle. We also analyze the relation between the regularity of the Riemannian metric and the regularity of the curvature of the associated principal S1-bundle on spinc manifolds with Killing spinors.

Lap belt injuries in children.

LENUS (Irish Health Repository)

McGrath, N

2010-07-01

The use of adult seat belts without booster seats in young children may lead to severe abdominal, lumbar or cervical spine and head and neck injuries. We describe four characteristic cases of lap belt injuries presenting to a tertiary children\\'s hospital over the past year in addition to a review of the current literature. These four cases of spinal cord injury, resulting in significant long-term morbidity in the two survivors and death in one child, arose as a result of lap belt injury. These complex injuries are caused by rapid deceleration characteristic of high impact crashes, resulting in sudden flexion of the upper body around the fixed lap belt, and consequent compression of the abdominal viscera between the lap belt and spine. This report highlights the dangers of using lap belts only without shoulder straps. Age-appropriate child restraint in cars will prevent these injuries.

Classical transport in a non-circular z-pinch

International Nuclear Information System (INIS)

Eriksson, G.

1987-05-01

A method is devised, in which particle and heat fluxes are found by solving the heat balance equation self-consistently for specified profiles. The procedure is applied to an equilibrium which corresponds to a non-circular z-pinch. (author)

A novel graphical technique for Pinch Analysis applications: Energy Targets and grassroots design

International Nuclear Information System (INIS)

Gadalla, Mamdouh A.

2015-01-01

Graphical abstract: A new HEN graphical design. - Highlights: • A new graphical technique for heat exchanger networks design. • Pinch Analysis principles and design rules are better interpreted. • Graphical guidelines for optimum heat integration. • New temperature-based graphs provide user-interactive features. - Abstract: Pinch Analysis is for decades a leading tool to energy integration for retrofit and design. This paper presents a new graphical technique, based on Pinch Analysis, for the grassroots design of heat exchanger networks. In the new graph, the temperatures of hot streams are plotted versus those of the cold streams. The temperature–temperature based graph is constructed to include temperatures of hot and cold streams as straight lines, horizontal lines for hot streams, and vertical lines for cold streams. The graph is applied to determine the pinch temperatures and Energy Targets. It is then used to synthesise graphically a complete exchanger network, achieving the Energy Targets. Within the new graph, exchangers are represented by inclined straight lines, whose slopes are proportional to the ratio of heat capacities and flows. Pinch Analysis principles for design are easily interpreted using this new graphical technique to design a complete exchanger network. Network designs achieved by the new technique can guarantee maximum heat recovery. The new technique can also be employed to simulate basic designs of heat exchanger networks. The strengths of the new tool are that it is simply applied using computers, requires no commercial software, and can be used for academic purposes/engineering education

Processes governing pinch formation in diodes

International Nuclear Information System (INIS)

Blaugrund, A.E.; Cooperstein, G.; Goldstein, S.A.

1975-01-01

The process of pinch formation in large aspect ratio diodes has been studied by means of streak photography and time-resolved x-ray detectors. A tight pinch is formed at the anode center by a collapsing thin hollow electron beam. The collapse velocity depends, among other things, on the type of material in the top 1 μm layer of the anode. In a tentative model it is assumed that an anode plasma is at least partially created from gases released from the surface layer of the anode by the heating action of the beam. These gases are ionized by primary, backscattered, and secondary electrons. Ions emitted from this plasma modify the electron trajectories in the diode leading to a radial collapse of the hollow electron beam. The observed monotonic dependence of the collapse velocity on the atomic number of the anode material can be explained by the smooth dependence on Z of both the specific heat and the electron backscatter coefficient. In the case of high-Z anodes the ion expansion time appears to be the factor limiting the collapse velocity. Detailed experimental data are presented

An ultra miniature pinch-focus discharge

International Nuclear Information System (INIS)

Soto, L.; Pavez, C.; Moreno, J.; Pavez, C.; Barbaglia, M.; Clausse, A.

2004-01-01

As a way to investigate the minimum energy to produce a pinch plasma focus discharge, an ultra miniature device has been designed and constructed (nano focus NF: 5 nF, 5-10 kV, 5-10 kA, 60-250 mJ, 16 ns time to peak current). Sub-millimetric anode radius covered by a coaxial insulator were used for experiments in hydrogen. Evidence of pinch was observed in electrical signals in discharges operating at 60 mJ. A single-frame image converter camera (4 ns exposure) was used to obtain plasma images in the visible range. The dynamics observed from the photographs is consistent with: a) formation of a plasma sheath close to the insulator surface, b) fast axial motion of the plasma sheath, c) radial compression over the anode, and d) finally the plasma is detached from the anode in the axial direction. The total time since stage a) to d) was observed to be about 30 ns. X ray and neutron emission is being studied. Neutron yield of the order of 10 3 neutrons per shot is expected for discharges operating in deuterium at 10 kA. (authors)

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

International Nuclear Information System (INIS)

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

2000-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2000-02-01

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

Generation of an intense ion beam by a pinched relativistic electron beam

International Nuclear Information System (INIS)

Gilad, P.; Zinamon, Z.

1976-01-01

The pinched electron beam of a pulsed electron accelerator is used to generate an intense beam of ions. A foil anode and vacuum drift tube are used. The space charge field of the pinched beam in the tube accelerates ions from the foil anode. Ion currents of 10 kA at a density of 5kA/cm 2 with pulse length of 50 ns are obtained using a 5 kJ, 450 kV, 3 Ω diode. (author)

Application of 2-D Simulations to Z-Pinch Experiment Design and Analysis

International Nuclear Information System (INIS)

Peterson, D.L.; Bowers, R.L.; Matuska, W.; Chandler, G.A.; Deeney, C.; Derzon, M.S.; Matzen, M.K.; Mock, R.C.; Nash, T.J.; Sanford, T.W.L.; Spielman, R.B.; Struve, K.W.

1998-01-01

The successful 2-D simulations of z-pinch experiments (reproducing such features as the measured experimental current drive, radiation pulse shape, peak power and total radiated energy) can lead to a better understanding of the underlying physics in z-pinch implosions and to the opportunity to use such simulations in the analysis of experimental data and in the design of new experiments. Such use has been made with LANL simulations of experiments on the Sandia Saturn and Z accelerators. Applications have included ''vacuum'' and ''dynamic'' hohlraum experiments; variations in mass, radius and length; and ''nested'' array configurations. Notable examples include the explanation of the power/length results in reduced length pinches and the prediction of the current best power and pulsewidth nested array experiment. Examples of circumstances where the simulation results do not match the experiments will be given along with a discussion of opportunities for improved simulation results

Compressibility Effects in the Dynamics of the Reversed-Field Pinch

International Nuclear Information System (INIS)

Onofri, M.; Malara, F.; Veltri, P.

2008-01-01

We study the reversed-field pinch through the numerical solution of the compressible magnetohydrodynamic equations. Two cases are investigated: In the first case the pressure is derived from an adiabatic condition, and in the second case the pressure equation includes heating terms due to resistivity and viscosity. In the adiabatic case a single helicity state is observed, and the reversed-field pinch configuration is formed for short time intervals and is finally lost. In the nonadiabatic case the system reaches a multiple helicity state, and the reversal parameter remains negative for a longer time. The results show the importance of compressibility in determining the large scale dynamics of the system

Production of ion beam by conical pinched electron beam diode

International Nuclear Information System (INIS)

Matsukawa, Y.; Nakagawa, Y.

1982-01-01

Some properties of the ion beam produced by pinched electron beam diode having conical shape electrodes and organic insulator anode was studied. Ion energy is about 200keV and the peak diode current is about 30 kA. At 11cm from the diode apex, not the geometrical focus point, concentrated ion beam was obtained. Its density is more than 500A/cm 2 . The mean ion current density within the radius of 1.6cm around the axis from conical diode is two or three times that from an usual pinched electron beam diode with flat parallel electrodes of same dimension and impedance under the same conditions. (author)

Pinch-off syndrome: transection of implantable central venous access device.

Science.gov (United States)

Sugimoto, Takuya; Nagata, Hiroshi; Hayashi, Ken; Kano, Nobuyasu

2012-11-30

As the population of people with cancer increases so does the number of patients who take chemotherapy. Majority of them are administered parentally continuously. Implantable central venous catheter device is a good choice for those patients; however, severe complication would occur concerning the devices. Pinch-off syndrome is one of the most severe complications. The authors report a severe case of pinch-off syndrome. The patient with the implantable central venous device could not take chemotherapy because the device occluded. Further examination revealed the transection of the catheter. The transected fragment of the catheter in the heart was successfully removed by using a loop snare placed through the right femoral vein.

Belt technology stretches conveyors' coverage

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-07-15

With China the leading growth engine in the conveyor market, leading belt manufacturers are establishing local manufacturing plants to boost their presence. Fenner is planning to almost triple production capacity over the next three years, with a third of its investment in China. Shanxi-Phoenix Conveyor Belt Systems is a joint venture between Phoenix Conveyor Belt Systems GmbH, now part of ContiTech Ag, and its Chinese partners Lu An Mining Group Co. Ltd. and Jingcheng Anthracite Group Co. Ltd. It manufacturers steel cable belts, PVC and multi-ply belts for coal mines and power plants. Recent belt designs by FennerEurope and Metso Minerals are reported. 2 photos.

Simulation of high-energy particle production through sausage and kink instabilities in pinched plasma discharges

International Nuclear Information System (INIS)

Haruki, Takayuki; Yousefi, Hamid Reza; Masugata, Katsumi; Sakai, Jun-Ichi; Mizuguchi, Yusuke; Makino, Nao; Ito, Hiroaki

2006-01-01

In an experimental plasma, high-energy particles were observed by using a plasma focus device, to obtain energies of a few hundred keV for electrons, up to MeV for ions. In order to study the mechanism of high-energy particle production in pinched plasma discharges, a numerical simulation was introduced. By use of a three-dimensional relativistic and fully electromagnetic particle-in-cell code, the dynamics of a Z-pinch plasma, thought to be unstable against sausage and kink instabilities, are investigated. In this work, the development of sausage and kink instabilities and subsequent high-energy particle production are shown. In the model used here, cylindrically distributed electrons and ions are driven by an external electric field. The driven particles spontaneously produce a current, which begins to pinch by the Lorentz force. Initially the pinched current is unstable against a sausage instability, and then becomes unstable against a kink instability. As a result high-energy particles are observed

Particle acceleration and neutron production at the necks of plasma pinches

International Nuclear Information System (INIS)

Trubnikov, B.A.

1986-01-01

Induction electric fields are shown to arise in a deuterium plasma pinch because of a redistribution of the current over the discharge cross section. These fields accelerate deuterons, which produce neutrons. The total current I 0 is assumed to be constant but to consist of two components: I 0 = I 1 +I 2 , where K 1 (t) is a decaying current in the main pinch, and I 2 (t) is an increasing current in the peripheral plasma around the pinch. The current I 1 produces fields B = 2I 1 /cr and E = I 1 c -2 ln(r/R) 2 , where R is some length. The current I 1 is assumed to fall off so rapidly that the deuterons of the peripheral plasma are not ''coiled'' by the magnetic field. They acquire a velocity v = (e/M) ∫ E dt = v/sub */ ln(R/r) 2 , where v/sub */ = eI 0 /Mc 2 , in an impulsive fashion. The functional dependence r 2 = R 2 exp(-v/v/sub */) follows

D-D fusion experiments using fast z pinches

International Nuclear Information System (INIS)

Spielman, R.B.; Baldwin, G.T.; Cooper, G.

1994-01-01

The development of high current (I > 10 MA) drivers provides us with a new tool for the study of neutron-producing plasmas in the thermal regime. The imploded deuterium mass (or collisionality) increases as I 2 and the ability of the driver to heat the plasma to relevant fusion temperatures improves as the power of the driver increases. Additionally, fast ( 2 fiber arrays were imploded in a fast z-pinch configuration on Sandia's Saturn facility generating up to 3 x 10 12 D-D neutrons. These experiments were designed to explore the physics of neutron-generating plasmas in a z-pinch geometry. Specifically, we intended to produce neutrons from a nearly thermal plasma where the electrons and ions have a nearly Maxwellian distribution. This is to be clearly differentiated from the more usual D-D beam-target neutrons generated in many dense plasma focus (DPF) devices

The Rayleigh-Taylor instability in the spherical pinch

International Nuclear Information System (INIS)

Chen, H.B.; Hilko, B.; Panarella, E.

1994-01-01

The spherical pinch (SP) concept is an outgrowth of the inertial confinement model (ICF). Unlike the ICF where instabilities, especially the Rayleigh-Taylor instability, have been studied extensively, the instability study of the spherical pinch has just begun. The Raleigh-Taylor instability is investigated for the first time in the SP in the present work. By using the simple condition for the Rayleigh-Taylor instability ∇p · ∇p < O (density and pressure gradients have opposite direction), we have qualitatively identified the regions for development of instabilities in the SP. It is found that the explosion phase (central discharge) is stable and instabilities take place in the imploding phase. However, the growth rate for the instability is not in exponential form, and the appearance of the Rayleigh-Taylor instability does not prevent the main shock wave from converging to the center of the sphere

D-D fusion experiments using fast Z pinches

International Nuclear Information System (INIS)

Spielman, R.B.; Baldwin, G.T.; Cooper, G.

1998-03-01

The development of high current (I > 10 MA) drivers provides the authors with a new tool for the study of neutron-producing plasmas in the thermal regime. The imploded deuterium mass (or collisionality) increases as I 2 and the ability of the driver to heat the plasma to relevant fusion temperatures improves as the power of the driver increases. Additionally, fast ( 2 fiber arrays were imploded in a fast z-pinch configuration on Sandia's Saturn facility generating up to 3 x 10 12 D-D neutrons. These experiments were designed to explore the physics of neutron-generating plasmas in a z-pinch geometry. Specifically, the authors intended to produce neutrons from a nearly thermal plasma where the electrons and ions have a nearly Maxwellian distribution. This is to be clearly differentiated from the more usual D-D beam-target neutrons generated in many dense plasma focus (DPF) devices

Drivers' attitudes toward front or rear child passenger belt use and seat belt reminders at these seating positions.

Science.gov (United States)

Kidd, David G; McCartt, Anne T

2014-01-01

Passengers, especially those in rear seating positions, use seat belts less frequently than drivers. In-vehicle technology can inform drivers when their passengers are unbuckled and encourage passengers to use belts. The current study collected information about drivers' attitudes toward passenger belt use and belt reminders for front passengers and children in back seats. A national telephone survey of 1218 people 18 and older was conducted, of which 477 respondents were drivers who transport a front seat passenger at least once a week and 254 were drivers who transport an 8- to 15-year-old child in the back seat. Respondents were asked about their attitudes toward belt use by their front passengers or rear child passengers and preferences for different passenger belt reminder features. Ninety percent of drivers who regularly transport front seat passengers said that the passengers always use seat belts. Reported belt use was even higher among 8- to 15-year-old children in the back seat (97%). Among the drivers whose children do not always buckle up, about half said their child unbuckled the belt during the trip. Almost every full-time belt use driver (96%) would encourage front passengers to buckle up if not belted, compared to 57 percent of part-time belt users and nonusers. In contrast, nearly every driver who transports children in the back seat would encourage their belt use, regardless of the driver's belt use habits. Most drivers who transport front passengers wanted passenger belt reminders to encourage passengers to buckle up. Most of these drivers wanted a chime/buzzer or warning light or text display and wanted the reminder to last indefinitely. Most drivers who transport child passengers in the rear seat wanted the vehicle to indicate whether child passengers are unbuckled. A large majority of these drivers wanted notifications via a visual diagram of seating positions and belt use, a chime/buzzer, and a warning light or text display. These drivers

Resistive wall modes in the EXTRAP T2R reversed-field pinch

Science.gov (United States)

Brunsell, P. R.; Malmberg, J.-A.; Yadikin, D.; Cecconello, M.

2003-10-01

Resistive wall modes (RWM) in the reversed field pinch are studied and a detailed comparison of experimental growth rates and linear magnetohydrodynamic (MHD) theory is made. RWM growth rates are experimentally measured in the thin shell device EXTRAP T2R [P. R. Brunsell et al., Plasma Phys. Controlled Fusion 43, 1 (2001)]. Linear MHD calculations of RWM growth rates are based on experimental equilibria. Experimental and linear MHD RWM growth rate dependency on the equilibrium profiles is investigated experimentally by varying the pinch parameter Θ=Bθ(a)/ in the range Θ=1.5-1.8. Quantitative agreement between experimental and linear MHD growth rates is seen. The dominating RWMs are the internal on-axis modes (having the same helicity as the central equilibrium field). At high Θ, external nonresonant modes are also observed. For internal modes experimental growth rates decrease with Θ while for external modes, growth rates increase with Θ. The effect of RWMs on the reversed-field pinch plasma performance is discussed.

Grip and Pinch Strength Norms for Michigan Workers

Directory of Open Access Journals (Sweden)

Joel M. Phillips M.S., OTRL

2013-06-01

Full Text Available The purpose of this study was to create a norm reference of current grip and pinch strength norms for working-age Michigan adults. This normative study included a convenience sample of 179 volunteers who were employees at car plants in South East Michigan or hospital sites in West Michigan. Participants’ ages ranged from between 20 and 62 years of age with a mean age of 49.15 years. There were 78 females (44% and 101 males (56%. Subjects were classified by gender and in the age categories of ages 20 to 49 years and ages 50-62 years. Grip and pinch strength norms were collected following the American Society of Hand Therapy protocol. The norms from these working adults were calculated with descriptive statistics for males and females in two age classifications: ages 20 to 49 and ages 50 to 62 years. Standard Errors (SE are better than the 1985 norms for both males and females ages 20 to 49 years. SEs are higher than the ages 20 to 49 years’ norms for the ages 50 to 62 years age categories in both males and females. These norms offer a point of comparison for clinicians to use for clients in Michigan who are ages 20 to 62 years and who have a goal to improve their grip strength. Clients’ grip and pinch strength could be compared to their age level or gender norms using the comparison for one standard deviation above, below, or at the means.

Material testing in a linear theta pinch

International Nuclear Information System (INIS)

Alani, R.; Azodi, H.; Naraghi, M.; Safaii, B.; Torabi-Fard, A.

1983-01-01

The interaction of stainless steel 316 and Inconel 625 alloys has been investigated with a thermonuclear-like plasma, n = 10 16 cm -3 and Tsub(i) = 1 keV, generated in the Alvand I linear theta pinch. The average power flux is 10 7 W/cm 2 and the interaction time nearly one μs. A theoretical analysis based on the formation of an observed impurity layer near the material, has been used to determine the properties of the impurity layer and the extent of the damage on the material. Although arcing has been observed, the dominant damage mechanism has been assessed to be due to evaporation. Exposure to single shots has produced very heavily defective areas and even surface cracks on the SS 316 sample, but no cracks were observed on Inconel 625 after exposure to even 18 shots. On the basis of temperature rise and evaporation a comparison is made among materials exposed to plasmas of a theta pinch, shock tube, present generation tokamak and an anticipated tokamak reactor. (orig.)

Analysis of pinching in deterministic particle separation

Science.gov (United States)

Risbud, Sumedh; Luo, Mingxiang; Frechette, Joelle; Drazer, German

2011-11-01

We investigate the problem of spherical particles vertically settling parallel to Y-axis (under gravity), through a pinching gap created by an obstacle (spherical or cylindrical, center at the origin) and a wall (normal to X axis), to uncover the physics governing microfluidic separation techniques such as deterministic lateral displacement and pinched flow fractionation: (1) theoretically, by linearly superimposing the resistances offered by the wall and the obstacle separately, (2) computationally, using the lattice Boltzmann method for particulate systems and (3) experimentally, by conducting macroscopic experiments. Both, theory and simulations, show that for a given initial separation between the particle centre and the Y-axis, presence of a wall pushes the particles closer to the obstacle, than its absence. Experimentally, this is expected to result in an early onset of the short-range repulsive forces caused by solid-solid contact. We indeed observe such an early onset, which we quantify by measuring the asymmetry in the trajectories of the spherical particles around the obstacle. This work is partially supported by the National Science Foundation Grant Nos. CBET- 0731032, CMMI-0748094, and CBET-0954840.

Belt conveyors for bulk materials. 6th ed.

Energy Technology Data Exchange (ETDEWEB)

NONE

2007-07-01

The 16 chapters are entitled: Belt conveyor general applications economics; Design considerations; Characteristics and conveyability of bulk materials; Capacities, belt widths and speeds; Belt conveyor idlers; Belt tension and power engineering; Belt selection; Pulleys and shafts; Curves; Steep angle conveying; Belt cleaners and accessories; Transfer points; Conveyor motor drives and controls; Operation, maintenance and safety; Belt takeups; and Emerging technologies. 6 apps.

Belt conveying of minerals

Energy Technology Data Exchange (ETDEWEB)

Stace, L.R.; Yardley, E.D. [University of Nottingham, Nottingham (United Kingdom). School of Civil Engineering

2008-02-15

A discussion of the history and economics of conveyor applications sets the scene. Conveyor design is investigated in detail, covering power requirements, belt tensioning, and hardware. Principles regarding construction and joining of belts are outlined and a helpful and practical overview of relevant standards, belt test methods, and issues surrounding standardisation is given. Conveyor belt systems can represent a significant operational hazard, so the authors have set out to highlight the important area of safety, with consideration given to fire/electrical resistance, as well as the interface between personnel and conveyor systems - including nip points and operational issues such as man-riding. Selected case studies illustrate some practical aspects of installation and operation, at Selby mine in the UK and Prosper-Haniel Colliery in Germany and others. 3 apps.

Method and apparatus for producing average magnetic well in a reversed field pinch

International Nuclear Information System (INIS)

Ohkawa, T.

1983-01-01

A magnetic well reversed field plasma pinch method and apparatus produces hot magnetically confined pinch plasma in a toroidal chamber having a major toroidal axis and a minor toroidal axis and a small aspect ratio, e.g. < 6. A pinch current channel within the plasma and at least one hyperbolic magnetic axis outside substantially all of the plasma form a region of average magnetic well in a region surrounding the plasma current channel. The apparatus is operated so that reversal of the safety factor q and of the toroidal magnetic field takes place within the plasma. The well-producing plasma cross section shape is produced by a conductive shell surrounding the shaped envelope and by coils. A shell is of copper or aluminium with non-conductive breaks, and is bonded to a thin aluminium envelope by silicone rubber. (author)

Pinching Solutions of Slender Cylindrical Jets

Science.gov (United States)

1993-06-01

NASA Langley Research Center, Hampton, VA 23681.2This research was supported in part by Fondo Nacional de Desarrollo Cientifico y Tecnologico (FONDE...concentrate on inviscid irrotational flows of liquid jets. A review article has been written by Bogy [2]. Of relevance is also the work of Chandrasekhar...equations become elliptic and allow the possibility of admissible pinching solutions described in this article . It is interesting to find that for jets

Evident anomalous inward particle pinch in full non-inductive plasmas driven by lower hybrid waves on Tore Supra

International Nuclear Information System (INIS)

Hoang, G.T.; Bourdelle, C.; Pegourie, B.; Artaud, J.F.; Bucalossi, J.; Clairet, F.; Fenzi-Bonizec, C.; Garbet, X.; Gil, C.; Guirlet, R.; Imbeaux, F.; Lasalle, J.; Loarer, T.; Lowry, C.; Schunke, B.; Travere, J.M.; Tsitrone, E.

2003-01-01

These slides present some characteristics concerning peaked density profile observed in Tore-Supra. It appears that density profile remains peaked for more than 3 minutes in fully LHCD (lower hybrid current drive) discharges. The absence of toroidal electric field and the fact that the ware pinch has vanished across the entire plasma show that toroidal electric field and ware pinch are not the cause of the peaked profile. It is shown that peaked profile is linked to transport properties and can only be explained by a particle pinch velocity 2 orders of magnitude above the neoclassical pinch. It is also shown that the radial profile is in agreement with Isitchenko's formula. (A.C.)

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

International Nuclear Information System (INIS)

Hartman, C.W.; Carlson, G.; Hoffman, M.; Werner, R.

1977-01-01

Conceptual DT and DD fusion reactors are discussed based on magnetic confinement with the high-plasma-density Z-pinch. The reactor concepts have no ''first wall'', the fusion neutrons and plasma energy being absorbed directly into a surrounding lithium vortex blanket. Efficient systems with low re-circulated power are projected, based on a flow-through pinch cycle for which overall Q values can approach 10. The conceptual reactors are characterized by simplicity, small minimum size (100MW(e)) and by the potential for minimal radioactivity hazards. (author)

A new graphical method for Pinch Analysis applications: Heat exchanger network retrofit and energy integration

International Nuclear Information System (INIS)

Gadalla, Mamdouh A.

2015-01-01

Energy integration is a key solution in chemical process and crude refining industries to minimise external fuel consumption and to face the impact of growing energy crises. Typical energy integration projects can reach a reduction of heating fuels and cold utilities by up to 40% compared with original designs or existing installations. Pinch Analysis is a leading tool and regarded as an efficient method to increase energy efficiency and minimise fuel flow consumptions. It is valid for both natures of design, grassroots and retrofit situations. It can practically be applied to synthesise a HEN (heat exchanger network) or modify an existing preheat train for minimum energy consumption. Heat recovery systems or HENs are networks for exchanging heat between hot and cold process sources. All heat transferred from hot process sources into cold process sinks represent the scope for energy integration. On the other hand, energies required beyond this integrated amount are to be satisfied by external utilities. Graphical representations of Pinch Analysis, such as Composite and Grand Composite Curves are very useful for grassroots designs. Nevertheless, in retrofit situation the analysis is not adequate and besides it is graphically tedious to represent existing exchangers on such graphs. This research proposes a new graphical method for the analysis of heat recovery systems, applicable to HEN retrofit. The new graphical method is based on plotting temperatures of process hot streams versus temperatures of process cold streams. A new graph is constructed for representing existing HENs. For a given network, each existing exchanger is represented by a straight line, whose slope is proportional to the ratio of heat capacities and flows. Further, the length of each exchanger line is related to the heat flow transferred across this exchanger. This new graphical representation can easily identify exchangers across the pinch, Network Pinch, pinching matches and improper placement

Moderately reverberant learning ultrasonic pinch panel.

Science.gov (United States)

Nikolovski, Jean-Pierre

2013-10-01

Tactile sensing is widely used in human-computer interfaces. However, mechanical integration of touch technologies is often perceived as difficult by engineers because it often limits the freedom of style or form factor requested by designers. Recent work in active ultrasonic touch technologies has made it possible to transform thin glass plates, metallic sheets, or plastic shells into interactive surfaces. The method is based on a learning process of touch-induced, amplitude-disturbed diffraction patterns. This paper proposes, first, an evolution in the design with multiple dipole transducers that improves touch sensitivity or maximum panel size by a factor of ten, and improves robustness and usability in moderately reverberant panels, and second, defines a set of acoustic variables in the signal processing for the evaluation of sensitivity and radiating features. For proof of concept purposes, the design and process are applied to 3.2- and 6-mm-thick glass plates with variable damping conditions. Transducers are bonded to only one short side of the rectangular substrates. Measurements show that the highly sensitive free lateral sides are perfectly adapted for pinch-touch and pinch-slide interactions. The advantage of relative versus absolute touch disturbance measurement is discussed, together with tolerance to abutting contaminants.

Solid fiber Z-pinches

International Nuclear Information System (INIS)

Lindemuth, I.R.

1989-01-01

One- and two-dimensional magnetohydrodynamic computations have been performed to study the behavior of solid deuterium fiber Z-pinch experiments performed at Los Alamos and the Naval Research Laboratory. The computations use a tabulated atomic data base and ''cold-start'' initial conditions. The computations predict that the solid fiber persists longer in existing experiments than previously expected and that the discharge actually consists of a relatively low-density, hot plasma which has been ablated from the fiber. The computations exhibit m = 0 behavior in the hot, exterior plasma prior to complete ablation of the solid fiber. The m = 0 behavior enhances the fiber ablation rate. 10 refs., 5 figs

Energy Conversion in Imploding Z-Pinch Plasma

International Nuclear Information System (INIS)

Fisher, V.I.; Gregorian, L.; Davara, G.; Kroupp, E.; Bernshtam, V.A.; Ralchenko, Yu. V.; Starobinets, A.; Maron, Y.

2002-01-01

Due to important applications, Z-pinches became a subject of extensive studies. In these studies, main attention is directed towards improvement in efficiency of electric energy conversion into high-power radiation burst. At present, knowledge available on physics of Z-pinch operation, plasma motion, atomic kinetics, and energy conversion is mainly knowledge of numerical simulation results. We believe further progress require (i) experimental determination of spatial distribution and time history of thermodynamic parameters and magnetic field, as well as (ii) utilization of this data for experiment-based calculation of r,t-distribution of driving forces, mass and energy fluxes, and local energy deposition rates due to each of contributing mechanisms, what provides an insight into a process of conversion of stored electric energy into radiation burst. Moreover, experimentally determined r, t-distribution of parameters may serve for verification of computer programs developed for simulation of Z-pinch operation and optimization of radiation output. Within this research program we performed detailed spectroscopic study of plasmas imploding in modest-size (25 kV, 5 kJ, 1.2 μs quaterperiod) gas-puff Z-pinch. This facility has reasonably high repetition rate and provides good reproducibility of results. Consistent with plasma ionization degree in the implosion period, measurements are performed in UV-visible spectral range. Observation of spectral lines emitted at various azimuthal angles f showed no dependence on f. Dependence on axial coordinate z is found to be weak in near-anode half of the anode-cathode gap. Based on these observations and restricting the measurements to near-anode half of the gap, an evolution of parameters is studied in time and radial coordinate r only. In present talk we report on determination of radial component of plasma hydrodynamic velocity u r (r,t), magnetic field B ζ (r,t), electron density n e (r,t), density of ions in various

Particle pinch with fully noninductive lower hybrid current drive in Tore Supra.

Science.gov (United States)

Hoang, G T; Bourdelle, C; Pégourié, B; Schunke, B; Artaud, J F; Bucalossi, J; Clairet, F; Fenzi-Bonizec, C; Garbet, X; Gil, C; Guirlet, R; Imbeaux, F; Lasalle, J; Loarer, T; Lowry, C; Travère, J M; Tsitrone, E

2003-04-18

Recently, plasmas exceeding 4 min have been obtained with lower hybrid current drive (LHCD) in Tore Supra. These LHCD plasmas extend for over 80 times the resistive current diffusion time with zero loop voltage. Under such unique conditions the neoclassical particle pinch driven by the toroidal electric field vanishes. Nevertheless, the density profile remains peaked for more than 4 min. For the first time, the existence of an inward particle pinch in steady-state plasma without toroidal electric field, much larger than the value predicted by the collisional neoclassical theory, is experimentally demonstrated.

Pinch technology in theory and its application to a biomass integrated gasification and humid air turbine process

Energy Technology Data Exchange (ETDEWEB)

Garcia, B.L.

1998-03-01

The Pinch Technology has become a powerful tool for the optimization of the design of heat exchanger networks during the last 20 years. In this work, the different aspects of the methodology have been studied both in a theoretical way and in a practical approach. The first part of the work is a systematic analysis of the pinch technology: what it is, how it works, what are its advantages and disadvantages. There is also a brief discussion about the pinch method and other methods which handle energy recovery problems. Once the philosophy of the pinch technology has been theoretically studied, the second part of the work is its application to two different processes. The first process analyzed is a relatively simple but realistically practical problem based on a two distillation columns system. The knowledge gained during the calculations of this process is used in the second and more complex one. This second process is an integrated biomass gasification and humid air turbine (IGHAT) which has been already optimized by a heat balance program. The application of the pinch technology to this process shows the huge potential for improvements that this technology can provide in order to save energy. All the calculations are handled by the pinch technology software program `SuperTarget`. This program is evaluated along the work. In spite of some shortcomings that have been noticed, the usefulness of the program can be claimed 26 refs, 28 figs, 7 tabs

VERO cells harbor a poly-ADP-ribose belt partnering their epithelial adhesion belt

Directory of Open Access Journals (Sweden)

Laura Lafon-Hughes

2014-10-01

Full Text Available Poly-ADP-ribose (PAR is a polymer of up to 400 ADP-ribose units synthesized by poly-ADP-ribose-polymerases (PARPs and degraded by poly-ADP-ribose-glycohydrolase (PARG. Nuclear PAR modulates chromatin compaction, affecting nuclear functions (gene expression, DNA repair. Diverse defined PARP cytoplasmic allocation patterns contrast with the yet still imprecise PAR distribution and still unclear functions. Based on previous evidence from other models, we hypothesized that PAR could be present in epithelial cells where cadherin-based adherens junctions are linked with the actin cytoskeleton (constituting the adhesion belt. In the present work, we have examined through immunofluorescence and confocal microscopy, the subcellular localization of PAR in an epithelial monkey kidney cell line (VERO. PAR was distinguished colocalizing with actin and vinculin in the epithelial belt, a location that has not been previously reported. Actin filaments disruption with cytochalasin D was paralleled by PAR belt disruption. Conversely, PARP inhibitors 3-aminobenzamide, PJ34 or XAV 939, affected PAR belt synthesis, actin distribution, cell shape and adhesion. Extracellular calcium chelation displayed similar effects. Our results demonstrate the existence of PAR in a novel subcellular localization. An initial interpretation of all the available evidence points towards TNKS-1 as the most probable PAR belt architect, although TNKS-2 involvement cannot be discarded. Forthcoming research will test this hypothesis as well as explore the existence of the PAR belt in other epithelial cells and deepen into its functional implications.

On finite larmor radius stabilization of Z-pinches

International Nuclear Information System (INIS)

Hellsten, T.

1982-12-01

Finite Larmor radius stabilization of Z-pinches is discussed. Stability criteria can be derived for a class of equilibria having constant mass and current density. The internal modes can be stabilized provided the line density not exceed a critical value of the order of 10 18 ions/m. (Author)

Analysis of staged Z-pinch implosion trajectories from experiments on Zebra

Science.gov (United States)

Ross, Mike P.; Conti, F.; Darling, T. W.; Ruskov, E.; Valenzuela, J.; Wessel, F. J.; Beg, F.; Narkis, J.; Rahman, H. U.

2017-10-01

The Staged Z-pinch plasma confinement concept relies on compressing an annular liner of high-Z plasma onto a target plasma column of deuterium fuel. The interface between the liner and target is stable against the Magneto-Rayleigh-Taylor Instability, which leads to effective fuel compression and makes the concept interesting as a potential fusion reactor. The liner initiates as a neutral gas puff, while the target plasma is a partially ionized (Zeff coaxial plasma gun. The Zebra pulsed power generator (1 MA peak current, 100 ns rise time) provides the discharge that ionizes the liner and drives the Z-pinch implosion. Diverse diagnostics observe the 100-300 km/s implosions including silicon diodes, photo-conducting detectors (PCDs), laser shadowgraphy, an XUV framing camera, and a visible streak camera. The imaging diagnostics track instabilities smaller than 0.1 mm, and Z-pinch diameters below 2.5 mm are seen at peak compression. This poster correlates the data from these diagnostics to elucidate implosion behavior dependencies on liner gas, liner pressure, target pressure, and applied, axial-magnetic field. Funded by the Advanced Research Projects Agency - Energy, DE-AR0000569.

Tungsten Z-Pinch Long Implosions on the Saturn Generator

International Nuclear Information System (INIS)

DOUGLAS, MELISSA R.; DEENEY, Christopher; SPIELMAN, RICK B.; COVERDALE, CHRISTINE A.; RODERICK, N.F.; HAINES, M.G.

1999-01-01

Recent success on the Saturn and Z accelerators at Sandia National Laboratories have demonstrated the ability to scale z-pinch parameters to increasingly larger current pulsed power facilities. Next generation machines will require even larger currents (>20 MA), placing further demands on pulsed power technology. To this end, experiments have been carried out on Saturn operating in a long pulse mode, investigating the potential of lower voltages and longer implosion times while still maintaining pinch fidelity. High wire number, 25 mm diameter tungsten arrays were imploded with implosion times ranging from 130 to 240 ns. The results were comparable to those observed in the Saturn short pulse mode, with risetimes on the order of 4.5 to 6.5 ns. Experimental data will be presented, along with two dimensional radiation magnetohydrodynamic simulations used to explain and reproduce the experiment

Pelvic belt effects on sacroiliac joint ligaments: a computational approach to understand therapeutic effects of pelvic belts.

Science.gov (United States)

Sichting, Freddy; Rossol, Jerome; Soisson, Odette; Klima, Stefan; Milani, Thomas; Hammer, Niels

2014-01-01

The sacroiliac joint is a widely described source of low back pain. Therapeutic approaches to relieve pain include the application of pelvic belts. However, the effects of pelvic belts on sacroiliac joint ligaments as potential pain generators are mostly unknown. The aim of our study was to analyze the influence of pelvic belts on ligament load by means of a computer model. Experimental computer study using a finite element method. A computer model of the human pelvis was created, comprising bones, ligaments, and cartilage. Detailed geometries, material properties of ligaments, and in-vivo pressure distribution patterns of a pelvic belt were implemented. The effects of pelvic belts on ligament strain were computed in the double-leg stance. Pelvic belts increase sacroiliac joint motion around the sagittal axis but decrease motion around the transverse axis. With pelvic belt application, most of the strained sacroiliac joint ligaments were relieved, especially the sacrospinous, sacrotuberous, and the interosseous sacroiliac ligaments. Sacroiliac joint motion and ligament strains were minute. These results agree with validation data from other studies. Assigning homogenous and linear material properties and excluding muscle forces are clear simplifications of the complex reality. Pelvic belts alter sacroiliac joint motion and provide partial relief of ligament strain that is subjectively marked, although minimal in absolute terms. These findings confirm theories that besides being mechanical stabilizers, the sacroiliac joint ligaments are likely involved in neuromuscular feedback mechanisms. The results from our computer model help with unraveling the therapeutic mechanisms of pelvic belts.

Modeling x-ray data for the Saturn z-pinch machine

International Nuclear Information System (INIS)

Matuska, W.; Peterson, D.; Deeney, C.; Derzon, M.

1997-01-01

A wealth of XRD and time dependent x-ray imaging data exist for the Saturn z-pinch machine, where the load is either a tungsten wire array or a tungsten wire array which implodes onto a SiO 2 foam. Also, these pinches have been modeled with a 2-D RMHD Eulerian computer code. In this paper the authors start with the 2-D Eulerian results to calculate time and spatially dependent spectra using both LTE and NLTE models. Then using response functions, these spectra are converted to XRD currents and camera images, which are quantitatively compared with the data. Through these comparisons, areas of good and lesser quality agreement are determined, and areas are identified where the 2-D Eulerian code should be improved

Reduction of thermal expansion in Z-pinches by electron beam assisted magnetic field generation

International Nuclear Information System (INIS)

Heikkinen, J.A.; Karttunen, S.J.

1989-01-01

Weak radial expansion of a Z-pinch plasma column during its strong initial ohmic heating phase is expected when the generation of a confining magnetic field is assisted by a correctly formed electron beam pulse. Appropriate one-dimensional magnetohydrodynamic equations are numerically solved, and the observed increase of plasma radius as a function of time for various discharge parameters is compared to a normal Z-pinch discharge initiation. (author)

30 CFR 57.4503 - Conveyor belt slippage.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Conveyor belt slippage. 57.4503 Section 57.4503... Control Installation/construction/maintenance § 57.4503 Conveyor belt slippage. (a) Surface belt conveyors...) Underground belt conveyors shall be equipped with a detection system capable of automatically stopping the...

Investigation of a new type charging belt

International Nuclear Information System (INIS)

Jones, N.L.

1994-01-01

There are many desirable characteristics for an electrostatic accelerator charging belt. An attempt has been made to find a belt that improves on these properties over the stock belt. Results of the search, procurement, and 1,500 hours of operational experience with a substantially different belt are reported

X-Pinch Plasma Generation Testing for Neutron Source Development and Nuclear Fusion

Directory of Open Access Journals (Sweden)

Hossam A.Gabbar

2018-04-01

Full Text Available Nuclear fusion is a sought-out technology in which two light elements are fused together to create a heavier element and releases energy. Two primary nuclear fusion technologies are being researched today: magnetic and inertial confinement. However, a new type of nuclear fusion technology is currently being research: multi-pinch plasma beams. At the University of Ontario Institute of Technology, there is research on multi-pinch plasma beam technology as an alternative to nuclear fusion. The objective is to intersect two plasma arcs at the center of the chamber. This is a precursor of nuclear fusion using multi-pinch. The innovation portion of the students’ work is the miniaturization of this concept using high energy electrical DC pulses. The experiment achieved the temperature of 2300 K at the intersection. In comparison to the simulation data, the temperature from the simulation is 7000 K at the intersection. Additionally, energy harvesting devices, both photovoltaics and a thermoelectric generator, were placed in the chamber to observe the viable energy extraction.

Wire-number effects on high-power annular z-pinches and some characteristics at high wire number

Energy Technology Data Exchange (ETDEWEB)

SANFORD,THOMAS W. L.

2000-05-23

Characteristics of annular wire-array z-pinches as a function of wire number and at high wire number are reviewed. The data, taken primarily using aluminum wires on Saturn are comprehensive. The experiments have provided important insights into the features of wire-array dynamics critical for high x-ray power generation, and have initiated a renaissance in z-pinches when high numbers of wires are used. In this regime, for example, radiation environments characteristic of those encountered during the early pulses required for indirect-drive ICF ignition on the NIF have been produced in hohlraums driven by x-rays from a z-pinch, and are commented on here.

Wire-number effects on high-power annular z-pinches and some characteristics at high wire number

International Nuclear Information System (INIS)

SANFORD, THOMAS W. L.

2000-01-01

Characteristics of annular wire-array z-pinches as a function of wire number and at high wire number are reviewed. The data, taken primarily using aluminum wires on Saturn are comprehensive. The experiments have provided important insights into the features of wire-array dynamics critical for high x-ray power generation, and have initiated a renaissance in z-pinches when high numbers of wires are used. In this regime, for example, radiation environments characteristic of those encountered during the early pulses required for indirect-drive ICF ignition on the NIF have been produced in hohlraums driven by x-rays from a z-pinch, and are commented on here

More efficient mushroom canning through pinch and exergy analysis

NARCIS (Netherlands)

Paudel, Ekaraj; Sman, van der Ruud G.M.; Westerik, Nieke; Awasthi, Ashutosh; Dewi, Belinda P.C.; Boom, Remko M.

2017-01-01

Conventional production of canned mushrooms involves multiple processing steps as vacuum hydration, blanching, sterilization, etc. that are intensive in energy and water usage. We analyzed the current mushroom processing technique plus three alternative scenarios via pinch and exergy analysis.

Electrical insulators for the theta-pinch fusion reactor

International Nuclear Information System (INIS)

Clinard, F.W. Jr.

1976-01-01

The five major applications for electrical insulators in the Reference Theta Pinch Reactor are as follows: (1) first-wall insulator, (2) blanket intersegment insulator, (3) graphite encapsulating insulator, (4) implosion coil insulator, and (5) compression coil insulator. Insulator design proposals and some preliminary test results are given for each application

Belt for picking up liquids

Energy Technology Data Exchange (ETDEWEB)

Sewell, R B.H.; Nelson, S P

1973-05-18

This belt for picking up liquids consists of a layer of strong material, e.g., coarse cloth, sewed on at least one layer of absorbing material, e.g., sponge cloth, the stitching being disposed along chevrons with their apexes along the central axis of the belt; the edges do not contain any other marks. This arrangement facilitates the expulsion of the absorbed liquid when the belt passes between compression rollers.

30 CFR 56.4503 - Conveyor belt slippage.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Conveyor belt slippage. 56.4503 Section 56.4503... Control Installation/construction/maintenance § 56.4503 Conveyor belt slippage. Belt conveyors within... shall attend the belt at the drive pulley when it is necessary to operate the conveyor while temporarily...

14 CFR 27.1413 - Safety belts.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Safety belts. 27.1413 Section 27.1413 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Safety Equipment § 27.1413 Safety belts. Each safety belt...

Persistence of Salmonella on egg conveyor belts is dependent on the belt type but not on the rdar morphotype.

Science.gov (United States)

Stocki, S L; Annett, C B; Sibley, C D; McLaws, M; Checkley, S L; Singh, N; Surette, M G; White, A P

2007-11-01

Commercial caged layer flocks in Alberta, Canada, are commonly monitored for Salmonella enterica serovar Enteritidis (SE) and S. enterica serovar Typhimurium (ST) by environmental sampling. In one recent case, a SE strain isolated from the egg conveyor belt was a source of persistent infection for the flock. This study was undertaken to examine Salmonella colonization on egg conveyor belts and to determine whether the rdar morphotype, a conserved physiology associated with aggregation and long-term survival, contributed to persistence. Four woven belts constructed of natural or nonnatural fibers and a 1-piece belt made of vinyl were tested with rdar-positive ST and SE strains and a rdar-negative ST DeltaagfD reference strain. The type of egg belt was the most important factor influencing Salmonella colonization and persistence. The vinyl belt, with the least surface area available for colonization, had the fewest Salmonella remaining after washing and disinfection, whereas the hemp-plastic belt, with the greatest surface area, had the most Salmonella remaining. Real-time gene expression indicated that the rdar morphotype was involved in colonizing the egg belt pieces; however, it was not essential for persistence. In addition, rdar-positive and rdar-negative strains were equally similarly to disinfection on the egg belt pieces. The results indicate that Salmonella can persist on a variety of egg belts by mechanisms other than the rdar morphotype, and that using egg conveyer belts with reduced surface area for bacterial colonization can lessen contamination problems.

Granulite belts of Central India with special reference to the Bhopalpatnam Granulite Belt: Significance in crustal evolution and implications for Columbia supercontinent

Science.gov (United States)

Vansutre, Sandeep; Hari, K. R.

2010-11-01

The Central Indian collage incorporates the following major granulite belts: (1) the Balaghat-Bhandara Granulite Belt (BBG), (2) the Ramakona-Katangi Granulite Belt (RKG), (3) the Chhatuabhavna Granulite (CBG) of Bilaspur-Raigarh Belt, (4) the Makrohar Granulite Belt (MGB) of Mahakoshal supracrustals, (5) the Kondagaon Granulite Belt (KGGB), (6) the Bhopalpatnam Granulite Belt (BGB), (7) the Konta Granulite Belt (KTGB) and (8) the Karimnagar Granulite Belt (KNGB) of the East Dharwar Craton (EDC). We briefly synthesize the general geologic, petrologic and geochronologic features of these belts and explain the Precambrian crustal evolution in Central India. On the basis of the available data, a collisional relationship between Bastar craton and the EDC during the Paleo-Mesoproterozoic is reiterated as proposed by the earlier workers. The tectonic evolution of only few of the orogenic belts (BGB in particular) of Central India is related to Columbia.

Electrostatic turbulence in the Z pinch corona

International Nuclear Information System (INIS)

Terry, R.E.

1994-01-01

The microstability of electrostatic waves in the periphery of a Z pinch is formulated and resolved for a new class of Vlasov meta-equilibria admitting self-similar solutions in the electron gyrokinetic limit. These equilibria are subject to strong radial motions, and a mild deviation from charge neutrality arises to maintain ion acceleration close to that of the magnetized electrons. A unique class of profiles in density, axial current, temperature, and drift speed defines these equilibria. They are characterized by (i) the interior pinch current, (ii) the interior number density, (iii) the parallel and perpendicular temperatures, (iv) the exterior axial electric field value at the initial time, and (v) the radial ion acceleration relative to that of the electrons. Unstable ion sound waves arise in this medium by coupling radial and axial free energy to azimuthal longitudinal oscillations. The waves grow only for a limited range of radial or axial Exb/B drift speeds and electron temperatures. The growth rate, which can be as large as 0.115ω pi , is found to scale proportional to plasma frequency over the density range from 10 12 to 10 18 ions cm -3

Warm dense matter study and pulsed-power developments for X-pinch equipment in Nagaoka University of Technology

International Nuclear Information System (INIS)

Sasaki, Toru; Miki, Yasutoshi; Tachinami, Fumitaka; Saito, Hirotaka; Takahashi, Takuya; Anzai, Nobuyuki; Kikuchi, Takashi; Aso, Tsukasa; Harada, Nob.

2014-01-01

In order to explore high energy density physics, we have performed WDM experiment by using several pulsed-power devices. To generate well-defined warm dense state for evaluating electrical conductivity and its properties, we have proposed an isochoric heating of foamed metal by using pulsed-power discharge. The proposed technique yields the electrical conductivity of warm dense matter with a well-defined temperature. To observe the warm dense matter, a pulsed-power generator based on a pulse-forming-network (PFN) was studied toward generating an intense point-spot-like X-ray source from X-pinch technique. From comparison of the designing and the actual inductances of the X-pinch system, the actual inductance of X-pinch system is 3.5 times higher than the designing inductance. To reduce the total inductance of X-pinch system, we will modify the gap switch system such as multi spake gap

Parameter scaling toward high-energy density in a quasi-steady flow Z-pinch

Science.gov (United States)

Hughes, M. C.; Shumlak, U.; Nelson, B. A.; Golingo, R. P.; Claveau, E. L.; Doty, S. A.; Forbes, E. G.; Kim, B.; Ross, M. P.

2016-10-01

Sheared axial flows are utilized by the ZaP Flow Z-Pinch Experiment to stabilize MHD instabilities. The pinches formed are 50 cm long with radii ranging from 0.3 to 1.0 cm. The plasma is generated in a coaxial acceleration region, similar to a Marshall gun, which provides a steady supply of plasma for approximately 100 us. The power to the plasma is partially decoupled between the acceleration and pinch assembly regions through the use of separate power supplies. Adiabatic scaling of the Bennett relation gives targets for future devices to reach high-energy density conditions or fusion reactors. The applicability of an adiabatic assumption is explored and work is done experimentally to clarify the plasma compression process, which may be more generally polytropic. The device is capable of a much larger parameter space than previous machine iterations, allowing flexibility in the initial conditions of the compression process to preserve stability. This work is supported by DoE FES and NNSA.

ZAPP: Z-pinch atomic physics program

International Nuclear Information System (INIS)

Reed, K.

1983-01-01

High-density and high-temperature plasmas have been produced in a z-pinch with a hollow gas puff. A number of interesting atomic-physics phenomena occur in these plasmas and some of these phenomena provide important diagnostic information for characterizing the plasmas. We have been interested in collisions of high-energy electrons with highly stripped ions in these plasmas. Such collisions may produce a population inversion which could result in stimulated emission in the x-ray regime

Turbulent transport in reversed field pinches

International Nuclear Information System (INIS)

Christiansen, J.P.; Roberts, K.V.

1976-01-01

MHD stability of the Reversed Field Pinch (RFP) relies on reversal of the toroidal field component in the outer plasma region. Interest in this configuration comes from its potential economic advantages as a thermonuclear reactor, since compared to a Tokamak the RFP supports a higher value of β, the ratio between plasma and total magnetic pressure. Results of computations on the time-evolution of the RFP using a 1D MHD model are reported. (orig./GG) [de

Observed use of automatic seat belts in 1987 cars.

Science.gov (United States)

Williams, A F; Wells, J K; Lund, A K; Teed, N

1989-10-01

Usage of the automatic belt systems supplied by six large-volume automobile manufacturers to meet the federal requirements for automatic restraints were observed in suburban Washington, D.C., Chicago, Los Angeles, and Philadelphia. The different belt systems studied were: Ford and Toyota (motorized, nondetachable automatic shoulder belt), Nissan (motorized, detachable shoulder belt), VW and Chrysler (nonmotorized, detachable shoulder belt), and GM (nonmotorized detachable lap and shoulder belt). Use of automatic belts was significantly greater than manual belt use in otherwise comparable late-model cars for all manufacturers except Chrysler; in Chrysler cars, automatic belt use was significantly lower than manual belt use. The automatic shoulder belts provided by Ford, Nissan, Toyota, and VW increased use rates to about 90%. Because use rates were lower in Ford cars with manual belts, their increase was greater. GM cars had the smallest increase in use rates; however, lap belt use was highest in GM cars. The other manufacturers supply knee bolsters to supplement shoulder belt protection; all--except VW--also provide manual lap belts, which were used by about half of those who used the automatic shoulder belt. The results indicate that some manufacturers have been more successful than others in providing automatic belt systems that result in high use that, in turn, will mean fewer deaths and injuries in those cars.

Use of Z pinch radiation sources for high pressure shock wave studies

International Nuclear Information System (INIS)

Asay, J.R.; Konrad, C.H.; Hall, C.A.; Trott, W.M.; Chandler, G.A.; Holland, K.G.; Fleming, K.J.; Trucano, T.G.

1998-01-01

Recent developments in pulsed power technology demonstrate use of intense radiation sources (Z pinches) for driving planar shock waves in samples with spatial dimensions larger than possible with other radiation sources. Initial indications are that the use of Z pinch sources can be used to produce planar shock waves in samples with diameters of a few millimeters and thicknesses approaching one half millimeter. These dimensions allow increased accuracy of both shock velocity and particle velocity measurements. The Z pinch radiation source uses imploding metal plasma induced by self-magnetic fields applied to wire arrays to produce high temperature x-ray environments in vacuum hohlraum enclosures. Previous experiments have demonstrated that planar shock waves can be produced with this approach. A photograph of a wire array located inside the vacuum hohlraum is shown here. Typically, a few hundred individual wires are used to produce the Z pinch source. For the shock wave experiments being designed, arrays of 120 to 240 tungsten wires with a diameter of 40 mm and with individual diameters of about 10 microm are used. Preliminary experiments have been performed on the Z pulsed radiation source to demonstrate the ability to obtain VISAR measurements in the Z accelerator environment. Analysis of these results indicate that another effect, not initially anticipated, is an apparent change in refractive index that occurs in the various optical components used in the system. This effect results in an apparent shift in the frequency of reflected laser light, and causes an error in the measured particle velocity. Experiments are in progress to understand and minimize this effect

Reversed field pinch diagnostics

International Nuclear Information System (INIS)

Weber, P.G.

1986-01-01

The Reversed Field Pinch (RFP) is a toroidal, axisymmetric magnetic confinement configuration characterized by a magnetic field configuration in which the toroidal magnetic field is of similar strength to the poloidal field, and is reversed at the edge compared to the center. The RFP routinely operates at high beta, and is a strong candidate for a compact fusion device. Relevant attributes of the configuration will be presented, together with an overview of present and planned experiments and their diagnostics. RFP diagnostics are in many ways similar to those of other magnetic confinement devices (such as tokamaks); these lectures will point out pertinent differences, and will present some diagnostics which provide special insights into unique attributes of the RFP

14 CFR 31.63 - Safety belts.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Safety belts. 31.63 Section 31.63 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS Design Construction § 31.63 Safety belts. (a) There must be a safety belt...

Evaluation of Particle Pinch and Diffusion Coefficients in the Edge Pedestal of DIII-D H-mode Discharges

Science.gov (United States)

Stacey, W. M.; Groebner, R. J.

2009-11-01

Momentum balance requires that the radial particle flux satisfy a pinch-diffusion relationship. The pinch can be evaluated in terms of measurable quantities (rotation velocities, Er, etc.) by the use of momentum and particle balance [1,2], the radial particle flux can be determined by momentum balance, and then the diffusion coefficient can be evaluated from the pinch diffusion relation using the measured density gradient. Applications to several DIII-D H-mode plasmas are presented. 6pt [1] W.M. Stacey, Contr. Plasma Phys. 48, 94 (2008). [2] W.M. Stacey and R.J. Groebner, Phys. Plasmas 15, 012503 (2008).

Self-similar oscillations of a Z pinch

International Nuclear Information System (INIS)

Felber, F.S.

1982-01-01

A new analytic, self-similar solution of the equations of ideal magnetohydrodynamics describes cylindrically symmetric plasmas conducting constant current. The solution indicates that an adiabatic Z pinch oscillates radially with a period typically of the order of a few acoustic transit times. A stability analysis, which shows the growth rate of the sausage instability to be a saturating function of wavenumber, suggests that the oscillations are observable

Ramp discharge in Z-pinch

Energy Technology Data Exchange (ETDEWEB)

Gaber, W.H.; Beshara, A.B.; El-Bialy, A.B.; Masoud, M.M. [Plasma and Nuclear Fusion Dept., N.R.C., Atomic Energy Authority, Enshass (Egypt)

2004-07-01

A ramp Z-pinch discharge is designed and built in order to increase the pinch ratio and obtain a maximum contraction, and to increase the temperature. The discharge chamber is a cylindrical Pyrex tube of 25 cm long, 18.5 cm, 20 cm inner and outer diameter and two circular Aluminum plates of radius 15 cm separated by 21 cm are inserted into the tube. The tube is filled with He gas at 0.1 mbar. Two capacitor banks are used, the first bank 30 {mu}F and the second fast bank 1.3 {mu}F. The charging voltage was 8 kV for both banks. The discharge current and voltage of each bank are measured by potential divider and Rogowski coil respectively. Also the plasma inductance and resistance are obtained for each case. The plasma inductance has its peak value 300 nH at 4 {mu}s, while the plasma resistance has it minimum 8 m{omega} at the same time in the case of conventional discharge (single bank). In the case of ramp discharge, the inductance has two peaks 440 nH, 380 nH at 4 {mu}s, 9.5 {mu}s respectively, while the resistance has two minimum 4 m{omega}, 20 m{omega} at at 4 {mu}s, 9.5 {mu}s respectively. The temperature has been measure spectroscopically by using relative continuum intensity ratio method. The temperature has its peak value 38 eV at 4 {mu}s for single bank case, while it larger peak value 55 eV for ramp case. (orig.)

30 CFR 77.1107 - Belt conveyors.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Belt conveyors. 77.1107 Section 77.1107 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY... § 77.1107 Belt conveyors. Belt conveyors in locations where fire would create a hazard to personnel...

46 CFR 169.723 - Safety belts.

Science.gov (United States)

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Safety belts. 169.723 Section 169.723 Shipping COAST... Control, Miscellaneous Systems, and Equipment § 169.723 Safety belts. Each vessel must carry a harness type safety belt conforming to Offshore Racing Council (ORC) standards for each person on watch or...

Plant trial of an under-belt capacitance and gamma-ray backscatter gauge for on-belt determination of moisture in coal

International Nuclear Information System (INIS)

Cutmore, N.G.; Rafter, P.T.; Abernethy, D.A.; Millen, M.J.

1989-01-01

A non-contacting under-belt capacitance and gamma-ray backscatter technique has been developed for the on-line measurement of moisture in coal. In this technique, moisture was correlated with radio frequency susceptance and conductance, determined using an under-belt capacitance sensor in which a fringing electric field interrogates a layer of coal on the conveyor belt directly about the sensor. To compensate for variations in the density and thickness of the coal layer, an under-belt gamma-ray backscatter gauge was used to measure an equivalent volume of coal. A plant trial of the technique was conducted at Stockton Borehole Colliery, NSW Australia, where the gauges were installed on the coking coal product conveyor. Product moistures, in the range 7-14%, were determined with r.m.s errors of 0.50 and 0.25 wt% using on-belt and static off-belt gauges, respectively. The difference in the on-belt and off-belt gauge measurement accuracy was attributed to sampling errors in the calibration of the on-belt gauge. 6 refs., 6 figs., 3 tabs

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

International Nuclear Information System (INIS)

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

2003-01-01

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

Nonlinear full two-fluid study of m=0 sausage instabilities in an axisymmetric Z pinch

International Nuclear Information System (INIS)

Loverich, J.; Shumlak, U.

2006-01-01

A nonlinear full five-moment two-fluid model is used to study axisymmetric instabilities in a Z pinch. When the electron velocity due to the current J is greater than the ion acoustic speed, high wave-number sausage instabilities develop that initiate shock waves in the ion fluid. This condition corresponds to a pinch radius on the order of a few ion Larmor radii

Current-driven instabilities of the kinetic shear Alfven wave: Application to reversed field pinches and spheromaks

International Nuclear Information System (INIS)

Meyerhofer, D.D.; Perkins, F.W.

1984-01-01

The kinetic Alfven wave is studied in a cylindrical force-free plasma with self-consistent magnetic fields. This equilibrium represents a reversed field pinch or a spheromak. The stability of the wave is found to depend on the ratio of the electron drift velocity to the Alfven velocity. This ratio varies inversely with the square root of the plasma line density. The critical line density using the Spitzer--Harm electron distribution function is found for reversed field pinches with deuterium plasmas to be approximately 2 x 10 18 and is 5 x 10 17 m -1 in spheromaks with hydrogen plasmas. The critical line density is in reasonable agreement with experimental data for reversed field pinches

Current driven instabilities of the kinetic shear Alfven wave: application to reversed field pinches and spheromaks

International Nuclear Information System (INIS)

Meyerhofer, D.D.; Perkins, F.W.

1984-04-01

The kinetic Alfven wave is studied in a cylindrical force-free plasma with self-consistent magnetic fields. This equilibrium represents a reversed field pinch or a spheromak. The stability of the wave is found to depend on the ratio of the electron drift velocity to the Alfven velocity. This ratio varies inversely with the square root of the plasma line density. The critical line density using the Spitzer-Harm electron distribution function is found for reversed field pinches with deuterium plasmas to be approximately 2 x 10 18 m -1 and is 5 x 10 17 m -1 in spheromaks with hydrogen plasmas. The critical line density is in reasonable agreement with experimental data for reversed field pinches

The physics of reversed-field pinch profile sustainment

International Nuclear Information System (INIS)

Moses, R.W.

1985-01-01

A description of the Reversed-Field Pinch (RFP) is given. There is experimental evidence that indicates that an RFP dynamo effect sustains field reversal in steady state. Three sustainment mechanisms are reviewed: the MHD model, the tangled discharge model, and the kinetic dynamo model. The relationship of these models to each another is discussed briefly

Statistical theory of field fluctuations in a reversed-field pinch

International Nuclear Information System (INIS)

Turner, L.

1982-01-01

A statistical description of three-dimensional, incompressible turbulence in an ideal, current-bearing, bounded magnetofluid is given both analytically and numerically. Our results are then compared with existing data taken from reversed-field pinch experiments

Increasing Z-pinch vacuum hohlraum capsule coupling efficiency

International Nuclear Information System (INIS)

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

2004-01-01

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

Characterization of aluminum x-pinch plasmas driven by the 0.5 TW Lion accelerator

International Nuclear Information System (INIS)

Qi, N.; Hammer, D.A.; Kalantantar, D.H.; Noonan, W.A.; Rondeau, G.; Workman, J.B.; Richardson, M.C.

1989-01-01

The x-pinch, obtained by crossing two fine wires at one or more points as the load for the 0.5 TW Lion accelerator, has been used as a bright x-ray source. High density and temperature hot spots are observed at the crossing point(s). From these hot spots, an intense, spatially confined burst of x-rays is emitted which can serve as a pump for resonant photo-pumping lasers. The authors present experimental results concerning the radiation emission using Al x-pinches. The optimum mass loading for different ionization stages of Al ions and the total x-ray energy yields are examined. The density and temperature of the plasma and the size of the hot spots are measures. Based upon the results of these experiments, the authors evaluate resonant photopumping schemes such as those involving Be-like ions, using the Al x-pinch emission as the pump source

The Ras suppressor Rsu-1 binds to the LIM 5 domain of the adaptor protein PINCH1 and participates in adhesion-related functions

International Nuclear Information System (INIS)

Dougherty, Gerard W.; Chopp, Treasa; Qi Shengmei; Cutler, Mary Lou

2005-01-01

Rsu-1 is a highly conserved leucine rich repeat (LRR) protein that is expressed ubiquitously in mammalian cells. Rsu-1 was identified based on its ability to inhibit transformation by Ras, and previous studies demonstrated that ectopic expression of Rsu-1 inhibited anchorage-independent growth of Ras-transformed cells and human tumor cell lines. Using GAL4-based yeast two-hybrid screening, the LIM domain protein, PINCH1, was identified as the binding partner of Rsu-1. PINCH1 is an adaptor protein that localizes to focal adhesions and it has been implicated in the regulation of adhesion functions. Subdomain mapping in yeast revealed that Rsu-1 binds to the LIM 5 domain of PINCH1, a region not previously identified as a specific binding domain for any other protein. Additional testing demonstrated that PINCH2, which is highly homologous to PINCH1, except in the LIM 5 domain, does not interact with Rsu-1. Glutathione transferase fusion protein binding studies determined that the LRR region of Rsu-1 interacts with PINCH1. Transient expression studies using epitope-tagged Rsu-1 and PINCH1 revealed that Rsu-1 co-immunoprecipitated with PINCH1 and colocalized with vinculin at sites of focal adhesions in mammalian cells. In addition, endogenous P33 Rsu-1 from 293T cells co-immunoprecipitated with transiently expressed myc-tagged PINCH1. Furthermore, RNAi-induced reduction in Rsu-1 RNA and protein inhibited cell attachment, and while previous studies demonstrated that ectopic expression of Rsu-1 inhibited Jun kinase activation, the depletion of Rsu-1 resulted in activation of Jun and p38 stress kinases. These studies demonstrate that Rsu-1 interacts with PINCH1 in mammalian cells and functions, in part, by altering cell adhesion

36 CFR 4.15 - Safety belts.

Science.gov (United States)

2010-07-01

... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Safety belts. 4.15 Section 4... TRAFFIC SAFETY § 4.15 Safety belts. (a) Each operator and passenger occupying any seating position of a motor vehicle in a park area will have the safety belt or child restraint system properly fastened at...

Migration of plasma points in the Z-pinch

International Nuclear Information System (INIS)

Afonin, V.I.

1995-01-01

The paper deals with the generation of a spontaneous magnetic field in Z-pinch sausage-type instability plasma and the effect of magnetic field on sausage-type instability movement. The presented evaluations of spontaneous magnetic fields and their role in the migration of plasma points are in a satisfactory agreement with the experimental data. 8 refs

Collapse of Z-pinch necks for inertial fusion

International Nuclear Information System (INIS)

Yan'kov, V.V.

1989-01-01

The ignition is possible under the condition of collapring z-pinch neck up to the diameter 10 -4 cm. The current pulse with duration 10 -7 s and 10 7 A must be applied to a cylinder of condensed D-T mixture in order to obtain the parameter ρr≥0.4 g/cm 2 . 22 refs

A reversed-field theta-pinch plasma machine

International Nuclear Information System (INIS)

Yasojima, Yoshiyuki; Ueda, Yoshihiro; Sasao, Hiroyuki; Ueno, Noboru; Tanaka, Toshihide

1984-01-01

Mitsubishi Electric has constructed a reversed-field theta-pinch machine at its Central Research Laboratory and initiated a series of plasma diagnostics and control studies for development of nuclear-fusion technology. Although the device has a linear configuration, a stable high-temperature, high-density toroidal plasma can be generated. The article describes the overall structure, vacuum system, power-supply system, and diagnostics and control system of the plasma machine. (author)

Toroidal equilibrium in an iron-core reversed field pinch

International Nuclear Information System (INIS)

Miller, G.

1984-04-01

An analytical theory of toroidal equilibrium in the ZT-40M reversed field pinch is obtained, including effects of iron cores and resistive shell. The iron cores alter the form of the equilibrium condition and cause the equilibrium to be unstable on the shell resistive time scale

Anisotropy of energy losses in high-current Z-pinches produced by the implosion of cylindrical tungsten wire arrays

Science.gov (United States)

Aleksandrov, V. V.; Volkov, G. S.; Grabovski, E. V.; Gritsuk, A. N.; Lakhtyushko, N. I.; Medovshchikov, S. F.; Oleinik, G. M.; Svetlov, E. V.

2014-02-01

Results are presented from measurements of the anisotropy of energy losses in high-current Z-pinches produced by the implosion of wire arrays at the ANGARA-5-1 facility at load currents of up to 4MA. The energy losses were measured in the radial direction and along the pinch axis from the anode side. The main diagnostics were time-integrated thermocouple calorimeters, nanosecond X-ray diodes (XRDs) with different filters, and a foil radiation calorimeter with a time resolution of 2 μs. The azimuthal anisotropy of energy losses was measured for different wire array configurations and different shapes of the high-voltage electrode. The presence of strong initial azimuthal inhomogeneity of the wire mass distribution (sectioned arrays), as well as the use of conical electrodes instead of plane ones, does not increase the azimuthal inhomogeneity of the total energy losses. For cylindrical wire arrays, energy losses in the radial direction are compared with those along the pinch axis. According to XRD and calorimetric measurements, the radiation yield per unit solid angle along the pinch axis is two to three times lower than that in the radial direction. In the axial direction, the energy flux density of the expanding plasma is two to three times lower than the radiation intensity. The measured radiation yield across the pinch is 2.5-5 kJ/sr, while that along the pinch axis is 1-2 kJ/sr. The results obtained by means of XRDs agree to within measurement errors with those obtained using the radiation calorimeter. It is found that the energy per unit solid angle carried by the expanding plasma in the radial direction does not exceed 10% of the soft X-ray yield. Analysis of the structure of time-integrated pinhole images and signals from the radial and axial XRDs shows that radiation emitted in the radial direction from the hot central region of the pinch is partially screened by the less dense surrounding plasma halo, whereas radiation emitted in the axial direction is a

Linking natural microstructures with numerical modeling of pinch-and-swell structures

Science.gov (United States)

Peters, Max; Berger, Alfons; Herwegh, Marco; Regenauer-Lieb, Klaus

2016-04-01

For a variety of geological problems, the change from homogeneous to localized deformation and the establishment of steady-state conditions are equally important. Here, we show that pinch-and-swell structures are ideal candidates for the study of the switch in deformation style and mechanism during ductile creep. We present an interdisciplinary approach to the onset of pinch-and-swell structures and to the flow conditions during pre- to post-localization stages in ductile rocks. For this reason, naturally boudinaged calcite veins, embedded in a calc-mylonite, and their microfabrics were investigated quantitatively. Remnants of slightly deformed calcite hosts build up the swells, showing twinning and minor dislocation glide as crystal plastic deformation mechanisms which are accompanied by subgrain rotation recrystallization (SGR). Towards the pinches, we find a gradient of severe grain size reduction through progressive SGR, developing a characteristic dislocation creep crystallographic preferred orientation (CPO). Along this gradient, the finest recrystallized calcite grains appear randomly oriented, expressed by a "smearing-out" of the CPO and missing systematics of misorientation angles in the most extended areas. We interpret this microstructure as a switch from dislocation dominated creep to grain boundary sliding processes. Further, we show that the onset of boudinage is independent on both the original orientation and grain size of calcite hosts. We implemented these microstructural observations into a layered elasto-visco-plastic finite element framework, tracing variations in grain size (Peters et al., 2015). We base the microstructural evolution on thermo-mechanical-chemical principles and end-member flow laws (Herwegh et al., 2014). The simulated pinch-and-swell structures indicate that low strain rates in the swells favor dislocation creep, whereas accelerated rates provoke continuous grain size reduction allowing strain accommodation by diffusion creep

Time resolved observations of helical disruptions in a gas embedded Z-pinch

International Nuclear Information System (INIS)

Favre, M.; Chuaqui, H.; Bruzzone, H.; Soto, L.; Wyndham, E.

1990-01-01

Multiframe holographic interferometry has been applied to a gas embedded Z-pinch driven by a 1.5 ω, 100 kV coaxial line generator. The Z-pinch is triggered by a 1.06 μm, 10 ns laser pulse, at the onset of the applied voltage. A hydrogen background pressure of 0.33 atmospheres, with a 3 cm interelectrode separation is used. The laser output is also doubled and it is passed through an optical system giving two or more pulses separated by up to 10 ns for the optical diagnostics. The complete evolution of the helical instability is observed and the main features are discussed. (Author)

The Pitt Innovation Challenge (PInCh): Driving Innovation in Translational Research Through an Incentive-Based, Problem-Focused Competition.

Science.gov (United States)

Fitzpatrick, Nicole Edgar; Maier, John; Yasko, Laurel; Mathias, David; Qua, Kacy; Wagner, Erika; Miller, Elizabeth; Reis, Steven E

2017-05-01

Translational research aims to move scientific discoveries across the biomedical spectrum from the laboratory to humans, and to ultimately transform clinical practice and public health policies. Despite efforts to accelerate translational research through national initiatives, several major hurdles remain. The authors created the Pitt Innovation Challenge (PInCh) as an incentive-based, problem-focused approach to solving identified clinical or public health problems at the University of Pittsburgh Clinical and Translational Science Institute in spring 2014. With input from a broad range of stakeholders, PInCh leadership arrived at the challenge question: How do we empower individuals to take control of their own health outcomes? The authors developed the PInCh's three-round proposal submission and review process as well as an online contest management tool to support the process. Ninety-two teams submitted video proposals in round one. Proposals included mobile applications (29; 32%), other information technology (19; 21%), and community program (22; 24%) solutions. Ten teams advanced to the final round, where three were awarded $100,000 to implement their solution over 12 months. In a 6-month follow-up survey, 6/11 (55%) team leaders stated the PInCh helped to facilitate connections outside their normal sphere of collaborators. Additional educational training sessions related to problem-focused research will be developed. The PInCh will be expanded to engage investment and industry communities to facilitate the translation of solutions to clinical practice via commercialization pathways. External organizations and other universities will be engaged to use the PInCh as a mechanism to fuel innovation in their spaces.

Drive alive: teen seat belt survey program.

Science.gov (United States)

Burkett, Katie M; Davidson, Steve; Cotton, Carol; Barlament, James; Loftin, Laurel; Stephens, James; Dunbar, Martin; Butterfield, Ryan

2010-08-01

To increase teen seat belt use among drivers at a rural high school by implementing the Drive Alive Pilot Program (DAPP), a theory-driven intervention built on highway safety best practices. The first component of the program was 20 observational teen seat belt surveys conducted by volunteer students in a high school parking lot over a 38-month period before and after the month-long intervention. The survey results were published in the newspaper. The second component was the use of incentives, such as gift cards, to promote teen seat belt use. The third component involved disincentives, such as increased police patrol and school policies. The fourth component was a programmatic intervention that focused on education and media coverage of the DAPP program. Eleven pre-intervention surveys and nine post-intervention surveys were conducted before and after the intervention. The pre- and post-intervention seat belt usage showed significant differences (p<0.0001). The average pre-intervention seat belt usage rate was 51.2%, while the average post-intervention rate was 74.5%. This represents a percentage point increase of 23.3 in seat belt use after the DAPP intervention. Based on seat belt observational surveys, the DAPP was effective in increasing seat belt use among rural high school teenagers. Utilizing a theory-based program that builds on existing best practices can increase the observed seat belt usage among rural high school students.

Electron temperature measurement in Z-pinch

International Nuclear Information System (INIS)

Gerusov, A.V.; Orlov, M.M.; Terent'ev, A.R.; Khrabrov, V.A.

1987-01-01

Measurement of temperature of emitting plasma sheath in noncylindrical Z-pinch in neon at the stage of convergence to the axis, based on comparing the intensity of spectral lines belonging to Ne1, Ne2, is performed. Line intensity relation dependence was determined using calculations according to emitting-collision model. Spectra were recorded by electron-optical converter and relative intensity was determined by subsequent photometry of photolayer. Cylindric symmetrical MHD-calculations during which temperature and the observed line intensity relation were determined, are conducted

MHD simulations of molybdenum X-pinches

International Nuclear Information System (INIS)

Ivanenkov, G.V.; Stepnevski, V.

2002-01-01

One investigates into compression of molybdenum X-pinches applying numerical MHD-models with parabolic and conical initial geometry. The second model describing plasma axial motion in greater detail offers a real geometry of a discharge and is applicable to loads characterized by higher masses in contrast to the first one. Both models enabled to describe all basic phases of compression including origination of a minidiode, occurrence of a narrow neck, microexplosion of a hot point and origination of shock waves followed by sausage instability [ru

Effect of cathode and anode plasma motion on current characteristics of pinch diode

International Nuclear Information System (INIS)

Yang Hailiang; Qiu Aici; Sun Jianfeng; Li Jingya; He Xiaoping; Tang Junping; Li Hongyu; Wang Haiyang; Huang Jianjun; Ren Shuqing; Yang Li; Zou Lili

2005-01-01

The preliminary research results for the effect of cathode and anode plasma motion on current characteristics of the pinch ion diode on FLASH II accelerator are reported. The structure and principle of pinch reflex ion beam diode are introduced. The time dependent evolution of electron and ion flow in large aspect-ratio relativistic diodes is studied by analytic models. The equation of Child-langmuir, weak focused-flow, strong focused-flow and parapotential flow are corrected to reduce the diode A-C gap caused by the motion of cathode and anode plasma. The diode current and ion current are calculated with these corrected equations, and the results are consistent with the experimental data. The methods of increasing ion current and efficiency are also presented. The high power ion beam peak current about 160 kA with a peak energy about 500 keV was produced using water-dielectric transmission-line generators with super-pinch reflex ion diodes on FLASH II accelerator at Northwest Institute of Nuclear Technology (NINT). (authors)

The role of radial particle pinches in ELM suppression by resonant magnetic perturbations

International Nuclear Information System (INIS)

Stacey, W.M.; Evans, T.E.

2011-01-01

The force balance in the plasma edge in a matched pair of DIII-D (Luxon 2002 Nucl. Fusion 42 6149) tokamak discharges with and without resonant magnetic perturbations (RMPs) is evaluated in order to investigate the effects on particle transport of RMP applied for the purpose of suppressing edge-localized modes (ELMs). Experimental data are used to evaluate the radial and toroidal force balances, which may be written as a pinch-diffusion relation for the radial ion flux to facilitate investigation of transport effects. The radial electric field in the H-mode plasma had a sharp negative dip in the steep gradient region of the edge pedestal, associated with which was a large inward pinch velocity. The main effect of RMP was to make the edge electric field less negative or more positive, reducing this strong negative dip in the radial electric field (even reversing it from negative to positive over some regions), thereby reducing the strong inward particle pinch in the edge of an H-mode discharge, thus causing a reduction in edge density below the ELM threshold.

An electron-beam-heating model for the Gamble II rod pinch

International Nuclear Information System (INIS)

Mosher, David; Schumer, Joseph; Hinshelwood, David; Weber, Bruce; Stephanakis, Stavros; Swanekamp, Stephen; Young, Frank

2002-01-01

The rod-pinch diode concentrates electron deposition onto the tip of a high-atomic-number, mm-dia. anode rod to create an ultra-bright x-ray source for multi-MV radiography. Here, a technique is presented whereby line-spread functions acquired on-axis and at 90 deg. to the rod are used to determine the electron-deposition distribution. Results show that the smaller measured on-axis spot size for heated rods on Gamble II is due to pinching closer to the tapered tip. For a diode power of 6x1010 W, peak electron heating of 1x1014 W/cm 3 is calculated. MHD calculations of the e-beam-heated rod response agree with Schlieren measurements of plasma expansion

Engineering feasibility evaluation of a peristaltic pinch

International Nuclear Information System (INIS)

Boicourt, G.P.

1977-04-01

A recent proposal for reducing the end loss of a linear theta pinch is to produce moving magnetic mirrors at the coil ends. The concept entails the sequential pulsing of an axially arranged series of two-turn coaxial coils. The electrical design of such a system presents some unique problems. Ideally, the individual pulse circuits should be completely independent. This would facilitate the design by eliminating interactive effects. In practice, the circuits must be interconnected through isolating inductors to enable the production of a uniform biasing magnetic field. Moreover, the coils must be located physically close together. This produces strong magnetic coupling between the pulse circuits, which can seriously affect the shape and speed of the inward-moving magnetic-mirror field. Possible systems were modeled for the NET-2 circuit analysis code. The models took account of the inductive coupling between the individual circuits in the model. The results show that an increasing magnetic mirror can be produced provided the radius of the theta pinch is not too great compared to the intercoil spacing. The peristaltic field can be maintained for several cycles in the inner coils. The voltage hold-off requirements on the pulse circuit switches are found to be severe, but not impossible to meet

Rotational instability in a linear theta pinch

International Nuclear Information System (INIS)

Ekdahl, C.; Bartsch, R.R.; Commisso, R.J.; Gribble, R.F.; McKenna, K.F.; Miller, G.; Siemon, R.E.

1980-01-01

The m=1 ''wobble'' instability of the plasma column in a 5-m linear theta pinch has been studied using an axial array of orthogonally viewing position detectors to resolve the wavelength and frequency of the column motion. The experimental results are compared with recent theoretical predictions that include finite Larmor orbit effects. The frequency and wavelength characteristics at saturation agree with the predicted dispersion relation for a plasma rotating faster than the diamagnetic drift speed. Measurements of the magnetic fields at the ends of the pinch establish the existence of currents flowing in such a way that they short out the radial electric fields in the plasma column. The magnitude of rotation, the observed delay in the onset of m=1 motion, and the magnitude of end-shorting currents can all be understood in terms of the torsional Alfven waves that communicate to the central plasma column the information that the ends have been shorted. The same waves are responsible for the torque which rotates the plasma and leads to the observed m=1 instability. Observations of the plasma in the presence of solid end plugs indicate a stabilization of high-m number modes and a reduction of the m=1 amplitude

Confinement in TPE-RX reversed field pinch

International Nuclear Information System (INIS)

Yagi, Y.; Bolzonella, T.; Canton, A.

2001-01-01

Characteristics of the confinement properties of a reversed field pinch (RFP), the TPE-RX (R/a=1.72/0.45 m, R and a are major and minor radii), are presented for the plasma current, I p of 0.2-0.4 MA. TPE-RX has been operational since 1998, and I p =0.5 MA and duration time of up to 0.1 s have been obtained separately. It is found that I p /N (=12x10 -14 Am, N is the line density) is higher than those of other RFPs and poloidal beta, β p , and energy confinement time, τ E , are 5-10% and 0.5-1 ms, respectively, which are comparable with those of other RFPs of comparable sizes (RFX and MST). Pulsed poloidal current drive has recently been tested and the result has shown a twofold improvement of β p and τ E . The improvement is discussed in terms of the dynamic trajectories in the F-Θ plane, where F and Θ are reversal and pinch parameters, respectively. The global confinement properties are compared between the locked and non-locked discharges, which yields a better understanding of the mode-locking phenomena in RFP plasmas. (author)

Dense transient pinches and pulsed power technology: research and applications using medium and small devices

International Nuclear Information System (INIS)

Soto, Leopoldo; Pavez, Cristian; Moreno, Jose; Cardenas, Miguel; Zambra, Marcelo; Tarifeno, Ariel; Huerta, Luis; Tenreiro, Claudio; Giordano, Jose Luis; Lagos, Miguel; Escobar, Rodrigo; Ramos, Jorge; Altamirano, Luis; Retamal, Cesar; Silva, Patricio

2008-01-01

The Plasma Physics and Plasma Technology Group of the Chilean Nuclear Energy Commission (CCHEN) has, since about ten years ago, used plasma production devices to study dense hot plasmas, particularly Z-pinches and plasma foci (PFs). In the case of Z-pinches, the studies include studies on the dynamics and stability of gas-embedded Z-pinches at currents of thermonuclear interest, and preliminary studies on wire arrays. For PF research, the aim of the work has been to characterize the physics of these plasmas and also to carry out the design and construction of smaller devices-in terms of both input energy and size-capable of providing dense hot plasmas. In addition, taking advantage of the experience in pulsed power technology obtained from experimental researches in dense transient plasmas, an exploratory line of pulsed power applications is being developed. In this paper, a brief review listing the most important results achieved by the Plasma Physics and Plasma Technology Group of the CCHEN is presented, including the scaling studies, PF miniaturization and diagnostics and research on Z-pinches at currents of thermonuclear interest. Then, exploratory applications of pulsed power are presented, including nanoflashes of radiation for radiography and substances detection, high pulsed magnetic fields generation and rock fragmentation.

Chaos on the conveyor belt.

Science.gov (United States)

Sándor, Bulcsú; Járai-Szabó, Ferenc; Tél, Tamás; Néda, Zoltán

2013-04-01

The dynamics of a spring-block train placed on a moving conveyor belt is investigated both by simple experiments and computer simulations. The first block is connected by a spring to an external static point and, due to the dragging effect of the belt, the blocks undergo complex stick-slip dynamics. A qualitative agreement with the experimental results can be achieved only by taking into account the spatial inhomogeneity of the friction force on the belt's surface, modeled as noise. As a function of the velocity of the conveyor belt and the noise strength, the system exhibits complex, self-organized critical, sometimes chaotic, dynamics and phase transition-like behavior. Noise-induced chaos and intermittency is also observed. Simulations suggest that the maximum complexity of the dynamical states is achieved for a relatively small number of blocks (around five).

X-ray spectroscopy for high energy-density X pinch density and temperature measurements (invited)

International Nuclear Information System (INIS)

Pikuz, S.A.; Shelkovenko, T.A.; Chandler, K.M.; Mitchell, M.D.; Hammer, D.A.; Skobelev, I.Y.; Shlyaptseva, A.S.; Hansen, S.B.

2004-01-01

X pinch plasmas produced from fine metal wires can reach near solid densities and temperatures of 1 keV or even more. Plasma conditions change on time scales as short as 5-10 ps as determined using an x-ray streak camera viewing a focusing crystal spectrograph or directly viewing the plasma through multiple filters on a single test. As a result, it is possible to determine plasma conditions from spectra with ∼10 ps time resolution. Experiments and theory are now coming together to give a consistent picture of the dynamics and kinetics of these high energy density plasmas with very high temporal and spatial precision. A set of diagnostic techniques used in experiments for spectrally, temporally, and spatially resolved measurements of X pinch plasmas is described. Results of plasma parameter determination from these measurements are presented. X ray backlighting of one x-pinch by another with ∼30 ps x-ray pulses enables the dynamics and kinetics to be correlated in time

Application of the Pinch analysis for the design of a cogeneration system in a paper mill; Aplicacion del analisis Pinch para el diseno de un sistema de cogeneracion en una industria papelera

Energy Technology Data Exchange (ETDEWEB)

Mani Gonzalez, A. G.; Arriola Medellin, A. [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1997-12-31

The Pinch Analysis is a set of principles, tools and rules for the design that allow the engineer find the best way to configure the elements of a process. In the last ten years it has been utilized for the design of new processes as well as in the energy optimization of existing processes. In this paper the tools utilized for the integration of a cogeneration system in a process for the production of paper is presented. It is also presented how the combined treatment of the Pinch Analysis and the exergy concept allows to define, before the detailed design, the cogeneration potential, the fuel consumption and the amount of pollutant emissions for different cogeneration schemes. [Espanol] El analisis Pinch es un conjunto de principios, herramientas y reglas de diseno que permiten al ingeniero encontrar la mejor manera de configurar los elementos de un proceso. En los ultimos diez anos se ha utilizado para el diseno de procesos nuevos asi como en la optimacion energetica de procesos existentes. En el presente articulo se presentan las herramientas utilizadas para la integracion de un sistema de cogeneracion en un proceso de produccion de papel. Se muestra tambien como el tratamiento combinado del analisis Pinch y el concepto de energia permite definir, antes del diseno detallado, el potencial de cogeneracion, el consumo de combustible y la cantidad de emisiones contaminantes para diferentes esquemas de cogeneracion.

Application of the Pinch analysis for the design of a cogeneration system in a paper mill; Aplicacion del analisis Pinch para el diseno de un sistema de cogeneracion en una industria papelera

Energy Technology Data Exchange (ETDEWEB)

Mani Gonzalez, A G; Arriola Medellin, A [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1998-12-31

The Pinch Analysis is a set of principles, tools and rules for the design that allow the engineer find the best way to configure the elements of a process. In the last ten years it has been utilized for the design of new processes as well as in the energy optimization of existing processes. In this paper the tools utilized for the integration of a cogeneration system in a process for the production of paper is presented. It is also presented how the combined treatment of the Pinch Analysis and the exergy concept allows to define, before the detailed design, the cogeneration potential, the fuel consumption and the amount of pollutant emissions for different cogeneration schemes. [Espanol] El analisis Pinch es un conjunto de principios, herramientas y reglas de diseno que permiten al ingeniero encontrar la mejor manera de configurar los elementos de un proceso. En los ultimos diez anos se ha utilizado para el diseno de procesos nuevos asi como en la optimacion energetica de procesos existentes. En el presente articulo se presentan las herramientas utilizadas para la integracion de un sistema de cogeneracion en un proceso de produccion de papel. Se muestra tambien como el tratamiento combinado del analisis Pinch y el concepto de energia permite definir, antes del diseno detallado, el potencial de cogeneracion, el consumo de combustible y la cantidad de emisiones contaminantes para diferentes esquemas de cogeneracion.

Electron beam generation in z-pinch discharges

Energy Technology Data Exchange (ETDEWEB)

Vikhrev, V.V.; Baronova, E.O. [Kurchatov Inst., Moscow (Russian Federation). Russian Research Center

1997-12-31

Numerical modelling of the process of electron beam generation in z-pinch discharges are presented. The proposed model represents the electron beam generation under turbulent plasma conditions. Strong current distribution inhomogeneity in the plasma column and the zigzag drift current motion through the plasma have accounted for the adequate generation process investigation. Electron beam is generated near the maximum of compression and it is not related with the current break effect. (author)

Necessary stability condition for field-reversed theta pinches

International Nuclear Information System (INIS)

Cary, J.R.

1981-03-01

Toroidal systems of arbitrary cross section without toroidal magnetic field are analyzed via the double adiabatic fluid equations. Such systems are shown to be unstable if there exists one closed field line on which the average of kapparB 2 is positive, where kappa is the curvature. A similar criterion is derived for linear systems and is applied to a noncircular z-pinch

30 CFR 75.1403-5 - Criteria-Belt conveyors.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Criteria-Belt conveyors. 75.1403-5 Section 75... Criteria—Belt conveyors. (a) Positive-acting stop controls should be installed along all belt conveyors... can be stopped or started at any location. (b) Belt conveyors used for regularly scheduled mantrips...

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

Drive Alive: Teen Seat Belt Survey Program

Directory of Open Access Journals (Sweden)

Loftin, Laurel

2010-08-01

Full Text Available Objective: To increase teen seat belt use among drivers at a rural high school by implementing the Drive Alive Pilot Program (DAPP, a theory-driven intervention built on highway safety best practices.Methods: The first component of the program was 20 observational teen seat belt surveys conducted by volunteer students in a high school parking lot over a 38-month period before and after the month-long intervention. The survey results were published in the newspaper. The second component was the use of incentives, such as gift cards, to promote teen seat belt use. The third component involved disincentives, such as increased police patrol and school policies. The fourth component was a programmatic intervention that focused on education and media coverage of the DAPP program.Results: Eleven pre-intervention surveys and nine post-intervention surveys were conducted before and after the intervention. The pre- and post-intervention seat belt usage showed significant differences (p<0.0001. The average pre-intervention seat belt usage rate was 51.2%, while the average post-intervention rate was 74.5%. This represents a percentage point increase of 23.3 in seat belt use after the DAPP intervention.Conclusion: Based on seat belt observational surveys, the DAPP was effective in increasing seat belt use among rural high school teenagers. Utilizing a theory-based program that builds on existing best practices can increase the observed seat belt usage among rural high school students. [West J Emerg Med. 2010; 11(3: 280-283.

Linking pinch analysis and bridge analysis to save energy by heat-exchanger network retrofit

International Nuclear Information System (INIS)

Bonhivers, Jean-Christophe; Moussavi, Alireza; Alva-Argaez, Alberto; Stuart, Paul R.

2016-01-01

Highlights: • The flow rate of cascaded heat in exchangers is presented between composite curves. • Reducing energy consumption implies decreasing the flow rate of cascaded heat. • Removing cross-pinch transfers is not necessary to reduce energy consumption. • Bridge modifications are necessary to reduce energy consumption. • Bridge modifications are evaluated on the Heat Exchanger Load Diagram. - Abstract: Reduction of energy requirements in the process industries results in increased profitability and better environmental performance. Methods for heat exchanger network (HEN) retrofit are based on thermodynamic analysis and insights, numerical optimization, or combined approaches. Numerical optimization-based methods are highly complex and may not guarantee identification of the global optimum. Pinch analysis, which is an approach based on thermodynamic analysis and composite curves, is the most widely used in the industry. Its simplicity, the use of graphical tools, and the possibility for the user to interact at each step of the design process help identify solutions with consideration of practical feasibility. In the last few years, bridge analysis has been developed for HEN retrofit. It includes the following tools: (a) the definition of the necessary conditions to reduce energy consumption which are expressed in the bridge formulation, (b) a method for enumerating the bridges, (c) the representation of the flow rate of cascaded heat through each existing exchanger on the energy transfer diagram (ETD), and (4) the use of the Heat Exchanger Load Diagram (HELD) to identify a suitable HEN configuration corresponding to modifications. It has been shown that reducing energy consumption implies decreasing the flow rate of cascaded heat through the existing exchangers across the entire temperature range between the hot and cold utilities. The ETD shows all possibilities to reduce the flow rate of cascaded heat through a HEN. The objective of this paper is

Opacity and gradients in aluminum wire array z-pinch implosions on the Z pulsed power facility

Energy Technology Data Exchange (ETDEWEB)

Ampleford, D. J., E-mail: damplef@sandia.gov; Hansen, S. B.; Jennings, C. A.; Jones, B.; Coverdale, C. A.; Harvey-Thompson, A. J.; Rochau, G. A.; Dunham, G.; Moore, N. W.; Harding, E. C.; Cuneo, M. E. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Chong, Y.-K.; Clark, R. W.; Ouart, N.; Thornhill, J. W.; Giuliani, J.; Apruzese, J. P. [Naval Research Laboratory, Washington, DC 20375 (United States)

2014-03-15

Aluminum wire array z pinches imploded on the Z generator are an extremely bright source of 1–2 keV radiation, with close to 400 kJ radiated at photon energies >1 keV and more than 50 kJ radiated in a single line (Al Ly-α). Opacity plays a critical role in the dynamics and K-shell radiation efficiency of these pinches. Where significant structure is present in the stagnated pinch this acts to reduce the effective opacity of the system as demonstrated by direct analysis of spectra. Analysis of time-integrated broadband spectra (0.8–25 keV) indicates electron temperatures ranging from a few 100 eV to a few keV are present, indicative of substantial temperature gradients.

Hotspot ignition using a Z-pinch precursor plasma in a magneto-inertial ICF scheme

International Nuclear Information System (INIS)

Chittenden, J.P.; Vincent, P.; Jennings, C.A.; Ciardi, A.

2006-01-01

Precursor plasma flow is a common feature of wire array Z-pinches. The precursor flow represents a fraction of the mass of the array which arrives on the axis early in time and remains confined at high density by the inertia of further material bombarding the axis. Later on, the main implosion of the Z-pinch then compresses this precursor to substantially higher density. We show that if the same system can be generated with a Deuterium-Tritium plasma then the precursor provides an ideal target for a cylindrical magneto-inertial ICF scheme. The implosion of the DT Z-pinch produces a dense, low temperature shell which compressively heats the precursor target to high temperatures and tamps its expansion. The azimuthal magnetic field in the hotspot is sufficient to reduce the Larmor radius for the alpha particles to much less than the hotspot size, which dramatically reduces the pR required for ignition. A computational analysis of this approach is presented, including a study of the thermonuclear burn wave propagation. The robustness of the scheme with respect to instabilities, confinement time and drive parameters is examined. The results indicate that a high energy gain can be achieved using Z-pinches with 50-100 MA currents and a few hundred nanosecond rise-times. This work was partially supported by the U.S. Department of Energy through cooperative agreement DE-FC03-02NA00057

Synchronous and Cogged Fan Belt Performance Assessment

Energy Technology Data Exchange (ETDEWEB)

Cutler, Dylan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Dean, Jesse [National Renewable Energy Lab. (NREL), Golden, CO (United States); Acosta, Jason [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2014-02-01

The GSA Regional GPG Team commissioned the National Renewable Energy Laboratory (NREL) to perform monitoring of cogged V-belts and synchronous belts on both a constant volume and a variable air volume fan at the Byron G. Rodgers Federal Building and U.S. Courthouse in Denver, Colorado. These motor/fan combinations were tested with their original, standard V-belts (appropriately tensioned by an operation and maintenance professional) to obtain a baseline for standard operation. They were then switched to the cogged V-belts, and finally to synchronous belts. The power consumption by the motor was normalized for both fan speed and air density changes. This was necessary to ensure that the power readings were not influenced by a change in rotational fan speed or by the power required to push denser air. Finally, energy savings and operation and maintenance savings were compiled into an economic life-cycle cost analysis of the different belt options.

Parametric dependences of momentum pinch and Prandtl number in JET

NARCIS (Netherlands)

Tala, T.; Salmi, A.; Angioni, C.; Casson, F. J.; Corrigan, G.; Ferreira, J.; Giroud, C.; Mantica, P.; Naulin, V.; Peeters, A.G.; Solomon, W. M.; Strintzi, D.; Tsalas, M.; Versloot, T. W.; de Vries, P. C.; Zastrow, K. D.

2011-01-01

Several parametric scans have been performed to study momentum transport on JET. A neutral beam injection modulation technique has been applied to separate the diffusive and convective momentum transport terms. The magnitude of the inward momentum pinch depends strongly on the inverse density

AUTOMATION OF CONVEYOR BELT TRANSPORT

Directory of Open Access Journals (Sweden)

Nenad Marinović

1990-12-01

Full Text Available Belt conveyor transport, although one of the most economical mining transport system, introduce many problems to mantain the continuity of the operation. Every stop causes economical loses. Optimal operation require correct tension of the belt, correct belt position and velocity and faultless rolls, which are together input conditions for automation. Detection and position selection of the faults are essential for safety to eliminate fire hazard and for efficient maintenance. Detection and location of idler roll faults are still open problem and up to now not solved successfully (the paper is published in Croatian.

2D radiation-magnetohydrodynamic simulations of SATURN imploding Z-pinches

International Nuclear Information System (INIS)

Hammer, J.H.; Eddleman, J.L.; Springer, P.T.

1995-01-01

Z-pinch implosions driven by the SATURN device at Sandia National Laboratory are modeled with a 2D radiation magnetohydrodynamic (MHD) code, showing strong growth of magneto-Rayleigh Taylor (MRT) instability. Modeling of the linear and nonlinear development of MRT modes predicts growth of bubble-spike structures that increase the time span of stagnation and the resulting x-ray pulse width. Radiation is important in the pinch dynamics keeping the sheath relatively cool during the run-in and releasing most of the stagnation energy. The calculations give x-ray pulse widths and magnitudes in reasonable agreement with experiments, but predict a radiating region that is too dense and radially localized at stagnation. We also consider peaked initial density profiles with constant imploding sheath velocity that should reduce MRT instability and improve performance. 2D krypton simulations show an output x-ray power > 80 TW for the peaked profile

Characterisation of Plasma Filled Rod Pinch electron beam diode operation

Science.gov (United States)

MacDonald, James; Bland, Simon; Chittenden, Jeremy

2016-10-01

The plasma filled rod pinch diode (aka PFRP) offers a small radiographic spot size and a high brightness source. It operates in a very similar to plasma opening switches and dense plasma focus devices - with a plasma prefill, supplied via a number of simple coaxial plasma guns, being snowploughed along a thin rod cathode, before detaching at the end. The aim of this study is to model the PFRP and understand the factors that affect its performance, potentially improving future output. Given the dependence on the PFRP on the prefill, we are making detailed measurements of the density (1015-1018 cm-3), velocity, ionisation and temperature of the plasma emitted from a plasma gun/set of plasma guns. This will then be used to provide initial conditions to the Gorgon 3D MHD code, and the dynamics of the entire rod pinch process studied.

Study of flow and loss processes at the ends of a linear theta pinch. Progress report, June 1, 1978--May 31, 1979

International Nuclear Information System (INIS)

York, T.M.; Klevans, E.H.

1979-02-01

Experimental and analytical studies of end loss from a linear theta pinch have been carried out. Analysis of reduced data on loss from a 25 cm long theta pinch has indicated: rotation at the end of pinch collapse, which appears to persist; ejection of the plasma in two modes, the first of which includes reversed, trapped fields; unique patterns of radial and axial variation of electron density in the end loss flow; substantial inaccuracies in plasma properties indicated by spectroscopy as compared to Thomson scattering. Studies of loss in a 50 cm long pinch with 50 eV, 2 x 10 16 cm -3 plasma are underway

Feed chute geometry for minimum belt wear

Energy Technology Data Exchange (ETDEWEB)

Roberts, A W; Wiche, S J [University of Newcastle, Newcastle, NSW (Australia). Centre for Bulk Solids and Particulate Technologies

1998-09-01

The paper is concerned with the feeding and transfer of bulk solids in conveyor belt operation. The paper focuses on chute design where the objective is to prevent spillage and minimise both chute and belt wear. It is shown that these objectives may be met through correct dynamic design of the chute and by directing the flow of bulk solids onto the belt at an acceptable incidence angle. The aim is to match the tangential velocity component of the feed velocity as close as possible to the belt velocity. At the same time, it is necessary to limit the impact pressure due to the change in momentum of the bulk solid as it feeds onto the belt. 2 refs., 8 figs.

Determination of relative immobile and sliding areas between carrying and tractive belts in using of belt conveyor intermediate drives

OpenAIRE

Goncharov K.A.

2015-01-01

Method of determination of relative immobile and sliding areas between carrying and tractive belts in places of mount-ing of belt conveyor intermediate drives made in the form of tractive contours is proposed. The example shows potential of this method in multidrive belt conveyor design process.

Optimization of a rod pinch diode radiography source at 2.3 MV

International Nuclear Information System (INIS)

Menge, P.R.; Johnson, D.L.; Maenchen, J.E.; Rovang, D.C.; Oliver, B.V.; Rose, D.V.; Welch, D.R.

2003-01-01

Rod pinch diodes have shown considerable capability as high-brightness flash x-ray sources for penetrating dynamic radiography. The rod pinch diode uses a small diameter (0.4-2 mm) anode rod extended through a cathode aperture. When properly configured, the electron beam born off of the aperture edge can self-insulate and pinch onto the tip of the rod creating an intense, small x-ray source. Sandia's SABRE accelerator (2.3 MV, 40 Ω, 70 ns) has been utilized to optimize the source experimentally by maximizing the figure of merit (dose/spot diameter2) and minimizing the diode impedance droop. Many diode parameters have been examined including rod diameter, rod length, rod material, cathode aperture diameter, cathode thickness, power flow gap, vacuum quality, and severity of rod-cathode misalignment. The configuration producing the greatest figure of merit uses a 0.5 mm diameter gold rod, a 6 mm rod extension beyond the cathode aperture (diameter=8 mm), and a 10 cm power flow gap to produce up to 3.5 rad (filtered dose) at 1 m from a 0.85 mm x-ray on-axis spot (1.02 mm at 3 deg. off axis). The resultant survey of parameter space has elucidated several physics issues that are discussed

30 CFR 75.1108 - Approved conveyor belts.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Approved conveyor belts. 75.1108 Section 75... Fire-Resistant Hydraulic Fluids on Underground Equipment § 75.1108 Approved conveyor belts. (a) Until December 31, 2009 conveyor belts placed in service in underground coal mines shall be: (1) Approved under...

Effectiveness of media and enforcement campaigns in increasing seat belt usage rates in a state with a secondary seat belt law.

Science.gov (United States)

Vasudevan, Vinod; Nambisan, Shashi S; Singh, Ashok K; Pearl, Traci

2009-08-01

In 2005, in terms of seat belt usage rates, Nevada ranked third nationally and first among states with secondary seat belt use enforcement laws in the United States. An effective combination of a media-based education and enforcement campaign helped in this regard. The objective of this article is to document the effectiveness of enforcement and media-based education and outreach campaigns on the seat belt usage rates in Nevada, a state with a secondary seat belt usage law. Observational data on seat belt usage and passenger fatality data are used to evaluate the effectiveness of enforcement campaigns and media-based education and outreach campaigns. Data based on observations of about 40,000 vehicles in each of the years 2003 to 2005 were analyzed. Statistical analyses show that a significant increase in seat belt usage rates among both drivers and passengers for both genders resulted from the accompanying the media and enforcement campaigns. The results from this study indicate that effective and well-planned media/enforcement campaigns can have a significant impact on seat belt usage rates even in a state where the enforcement of seat belt laws can only be as a secondary violation. They validate and expand on findings from other efforts documented in the literature. These results demonstrate that, if coordinated properly, media and enforcement campaigns work very effectively in increasing seat belt usage rates even in states with secondary seat belt laws.

Determination of relative immobile and sliding areas between carrying and tractive belts in using of belt conveyor intermediate drives

Directory of Open Access Journals (Sweden)

Goncharov K.A.

2015-12-01

Full Text Available Method of determination of relative immobile and sliding areas between carrying and tractive belts in places of mount-ing of belt conveyor intermediate drives made in the form of tractive contours is proposed. The example shows potential of this method in multidrive belt conveyor design process.

Modelling high density phenomena in hydrogen fibre Z-pinches

International Nuclear Information System (INIS)

Chittenden, J.P.

1990-09-01

The application of hydrogen fibre Z-pinches to the study of the radiative collapse phenomenon is studied computationally. Two areas of difficulty, the formation of a fully ionized pinch from a cryogenic fibre and the processes leading to collapse termination, are addressed in detail. A zero-D model based on the energy equation highlights the importance of particle end losses and changes in the Coulomb logarithm upon collapse initiation and termination. A 1-D Lagrangian resistive MHD code shows the importance of the changing radial profile shapes, particularly in delaying collapse termination. A 1-D, three fluid MHD code is developed to model the ionization of the fibre by thermal conduction from a high temperature surface corona to the cold core. Rate equations for collisional ionization, 3-body recombination and equilibration are solved in tandem with fluid equations for the electrons, ions and neutrals. Continuum lowering is found to assist ionization at the corona-core interface. The high density plasma phenomena responsible for radiative collapse termination are identified as the self-trapping of radiation and free electron degeneracy. A radiation transport model and computational analogues for the effects of degeneracy upon the equation of state, transport coefficients and opacity are implemented in the 1-D, single fluid model. As opacity increases the emergent spectrum is observed to become increasingly Planckian and a fall off in radiative cooling at small radii and low frequencies occurs giving rise to collapse termination. Electron degeneracy terminates radiative collapse by supplementing the radial pressure gradient until the electromagnetic pinch force is balanced. Collapse termination is found to be a hybrid process of opacity and degeneracy effects across a wide range of line densities with opacity dominant at large line densities but with electron degeneracy becoming increasingly important at lower line densities. (author)

Investigation of plasma turbulence in a theta-pinch-discharge

International Nuclear Information System (INIS)

Lins, G.

1980-01-01

This thesis is concerned with investigations of plasma turbulence in a 3 KJ Theta-Pinch during implosion by high-frequency Stark-effect and Thomson scattering. The next points are modifications of electron-distribution function by ionization in low preionizized turbulent plasma and energy losses by particle flow and heat flow at the ends. (HT)

Crustal Deformation around Zhangjiakou-Bohai Seismically Active Belt

Science.gov (United States)

Jin, H.; Fu, G.; Kato, T.

2011-12-01

Zhangjiakou-Bohai belt is a seismically active belt located in Northern China around Beijing, the capital of China. Near such a belt many great earthquakes occurred in the past centuries (e.g. the 1976 Tanshan Ms7.8 earthquake, the 1998 Zhangbei Ms6.2 earthquake, etc). Chinese Government established dense permanent and regional Global Positioning System (GPS) stations in and near the area. We collected and analyzed all the GPS observation data between 1999 and 2009 around Zhangjiakou-Bohai seismic belt, and obtained velocities at 143 stations. At the same time we investigated Zhangjiakou-Bohai belt slip rate for three profiles from northwest to southeast, and constructed a regional strain field on the Zhangjiakou-Bohai seismic belt region by least-square collocation. Based on the study we found that: 1) Nowadays the Zhangjiakou-Bohai seismic belt is creeping with left-lateral slip rate of 2.0mm~2.4mm/a, with coupling depth of 35~50km; 2) In total, the slip and coupling depth of the northwestern seismic belt is less than the one of southeast side; 3) The maximum shear strain is about 3×10-8 at Beijing-Tianjin-Tangshan area.

Simulation and modeling of the Gamble II self-pinched ion beam transport experiment

International Nuclear Information System (INIS)

Rose, D.V.; Ottinger, P.F.; Hinshelwood, D.D.

1999-01-01

Progress in numerical simulations and modeling of the self-pinched ion beam transport experiment at the Naval Research Laboratory (NRL) is reviewed. In the experiment, a 1.2-MeV, 100-kA proton beam enters a 1-m long, transport region filled with a low pressure gas (30--250 mTorr helium, or 1 Torr air). The time-dependent velocity distribution function of the injected ion beam is determined from an orbit code that uses a pinch-reflex ion diode model and the measured voltage and current from this diode on the Gamble II generator at NRL. This distribution function is used as the beam input condition for numerical simulations carried out using the hybrid particle-in-cell code IPROP. Results of the simulations will be described, and detailed comparisons will be made with various measurements, including line-integrated electron-density, proton-fluence, and beam radial-profile measurements. As observed in the experiment, the simulations show evidence of self-pinching for helium pressures between 35 and 80 mTorr. Simulations and measurements in 1 Torr air show ballistic transport. The relevance of these results to ion-driven inertial confinement fusion will be discussed

Measurements of high energy photons in Z-pinch experiments on primary test stand

International Nuclear Information System (INIS)

Si, Fenni; Zhang, Chuanfei; Xu, Rongkun; Yuan, Xi; Huang, Zhanchang; Xu, Zeping; Ye, Fan; Yang, Jianlun; Ning, Jiamin; Hu, Qingyuan; Zhu, Xuebin

2015-01-01

High energy photons are measured for the first time in wire-array Z-pinch experiments on the Primary Test Stand (PTS) which delivers a current up to 8 MA with a rise time of 70 ns. A special designed detecting system composed of three types of detectors is used to measure the average energy, intensity, and pulse waveform of high energy photons. Results from Pb-TLD (thermoluminescence dosimeter) detector indicate that the average energy is 480 keV (±15%). Pulse shape of high energy photons is measured by the photodiode detector consisted of scintillator coupled with a photodiode, and it is correlated with soft x-ray power by the same timing signal. Intensity is measured by both TLD and the photodiode detector, showing good accordance with each other, and it is 10 10 cm −2 (±20%) at 2 m in the horizontal direction. Measurement results show that high energy photons are mainly produced in pinch regions due to accelerated electrons. PTS itself also produces high energy photons due to power flow electrons, which is one order smaller in amplitude than those from pinch region

Study of soft X-ray energy spectra from gas-puff Z-pinch plasma

International Nuclear Information System (INIS)

Zou Xiaobing; Wang Xinxin; Zhang Guixin; Han Min; Luo Chengmu

2006-01-01

A ROSS-FILTER-PIN spectrometer in the spectral range of 0.28 keV-1.56 keV was developed to study the soft X-ray radiation emitted from gas-puff Z-pinch plasma. It is composed of five channels covering the energy interval of interest without gaps. Soft X-ray spectral energy cuts were determined by the L absorption edges of selected filter elements (K absorption edges being used for light filter elements), and the optimum thickness of filter material was designed using computer code. To minimize the residual sensitivity outside the sensitivity range of each channel, element of the first filter was added into the second filter of all the Ross pair. To diminish the area of each filter, PIN detector with small sensitive area of 1 mm 2 was adopted for the spectrometer. A filter with small area is easy to fabricate and would be helpful to withstand the Z-pinch discharge shock wave. With this ROSS-FILTER-PIN spectrometer, the energy spectra of soft X-ray from a small gas-puff Z-pinch were investigated, and the correlation between the soft X-ray yield and the plasma implosion state was also studied. (authors)

Anode plasma dynamics in the self-magnetic-pinch diode

Directory of Open Access Journals (Sweden)

Nichelle Bruner

2011-02-01

Full Text Available The self-magnetic-pinch diode is being developed as an intense electron beam source for pulsed-power-driven x-ray radiography. In high-power operation, the beam electrons desorb contaminants from the anode surface from which positive ions are drawn to the cathode. The counterstreaming electrons and ions establish an equilibrium current. It has long been recognized, however, that expanding electrode plasmas can disrupt this equilibrium and cause rapid reduction of the diode impedance and the radiation pulse. Recently developed numerical techniques, which enable simultaneous modeling of particle currents with 10^{13}  cm^{-3} densities to plasmas of near solid density, are applied to a model of the self-magnetic-pinch diode which includes the formation and evolution of anode surface plasmas. Two mechanisms are shown to cause rapid impedance loss, anode plasma expansion into the anode-cathode (A-K gap, and increased ion space-charge near the cathode surface. The former mechanism dominates for shorter A-K gaps, while the latter dominates for longer gaps. Model results qualitatively reproduce the time-dependent impedances measured for this diode.

Z-pinch driven fusion energy

International Nuclear Information System (INIS)

Slutz, Stephen A.; Olson, Craig L.; Rochau, Gary E.; Dezon, Mark S.; Peterson, P.F.; Degroot, J.S.; Jensen, N.; Miller, G.

2000-01-01

The Z machine at Sandia National Laboratories (SNL) is the most powerful multi-module synchronized pulsed-power accelerator in the world. Rapid development of z-pinch loads on Z has led to outstanding progress in the last few years, resulting in radiative powers of up to 280 TW in 4 ns and a total radiated x-ray energy of 1.8 MJ. The present goal is to demonstrate single-shot, high-yield fusion capsules. Pulsed power is a robust and inexpensive technology, which should be well suited for Inertial Fusion Energy, but a rep-rated capability is needed. Recent developments have led to a viable conceptual approach for a rep-rated z-pinch power plant for IFE. This concept exploits the advantages of going to high yield (a few GJ) at low rep-rate (approximately 0.1 Hz), and using a Recyclable Transmission Line (RTL) to provide the necessary standoff between the fusion target and the power plant chamber. In this approach, a portion of the transmission line near the capsule is replaced after each shot. The RTL should be constructed of materials that can easily be separated from the liquid coolant stream and refabricated for a subsequent shots. One possibility is that most of the RTL is formed by casting FLiBe, a salt composed of fluorine, lithium, and beryllium, which is an attractive choice for the reactor coolant, with chemically compatible lead or tin on the surface to provide conductivity. The authors estimate that fusion yields greater than 1 GJ will be required for efficient generation of electricity. Calculations indicate that the first wall will have an acceptable lifetime with these high yields if blast mitigation techniques are used. Furthermore, yields above 5 GJ may allow the use of a compact blanket direct conversion scheme

Method of monitoring, inspecting or testing conveyor belts

International Nuclear Information System (INIS)

Van der Walt, A.J.

1985-01-01

An invention is discussed which provides a method, installation and kit for monitoring, inspecting or testing a conveyor belt. Provision is made to transmit penetrating rays such as X-rays through a moving conveyor belt, forming a visible moving image from rays transmitted through the belt, and visually inspecting such moving image, after recording it if desired, to ascertain the condition of the interior of the belt. Typically an X-ray tube head is used to transmit the rays through the belt to a fluorescent screen which forms the image. The moving image can be recorded by means of a video camera

Generation of a subgigagauss magnetic field by pinching the plasma channel of exploded-wire

International Nuclear Information System (INIS)

Bogolyubsky, S.L.

1990-01-01

An interest in the dense pinches produced in the explosion of thin wires in the diodes of high current-nanosecond-REB-generators is provided by an opportunity to obtain high temperature-dense plasma configurations as an object of fusion studies and that in the spectroscopy of multi-charged ions. One needs to have a micrometer size of the Z-pinch neck to ignite the fusion reaction. The plasma channel pinching of the wires exploded by a megaampere current to a micrometer size of its neck can provide gigagauss magnetic fields. An important aspect of a given study is verification of an opportunity to obtain the radiation collapse of the plasma channel due to an exploded wire along its whole length up to the kA because of a line radiation cut-off due to the Braginsky-Pease current reduction to 150-200 from the plasma with left-angle Z right-angle much-gt 1. This paper presents experimental studies in this field, with the currents 0.2 MA, 0.5 MA, 1.2 MA

Effect of plasma formation on electron pinching and microwave emission in a virtual cathode oscillator

International Nuclear Information System (INIS)

Yatsuzuka, M.; Nakayama, M.; Nobuhara, S.; Young, D.; Ishihara, O.

1996-01-01

Time and spatial evolutions of anode and cathode plasmas in a vircator diode were observed with a streak camera. A cathode plasma appeared immediately after the rise of a beam current and was followed by an anode plasma typically after about 30 ns. Both plasmas expanded with almost the same speed of order of 104 m/s. The anode plasma was confirmed as a hydrogen plasma with an optical filter for H β line and study of anode-temperature rise. Electron beam pinching immediately followed by microwave emission was observed at the beam current less than the critical current for diode pinching in the experiment and the simulation. The electron beam current in the diode region is well characterized by the electron space-charge-limited current in bipolar flow with the expanding plasmas between the anode-cathode gap. As a result, electron bombardment produced the anode plasma, which made the electron beam strongly pinched, resulting in virtual cathode formation and microwave emission. (author). 5 figs., 5 refs

The development of an electronic system to continually monitor, indicate and control, 'belt slippage' in industrial friction 'V' belt drive transmission systems

International Nuclear Information System (INIS)

Brown, R E

2012-01-01

Belts have been used for centuries as a mechanism to transfer power from some form of drive system to a variety of load systems. Within industry today, many designs of belts but particularly friction, trapezoidal shaped 'V' belts are used and generally transfer power generated by electrical motors to numerous forms of driven load systems. It is suggested that belt systems, through their simplicity are sadly neglected by maintenance functions and generally are left unattended until high degrees of 'belt slippage' through loss of friction or 'belt breakage' provokes maintenance attention. These circumstances are most often identified through the reduced or loss of manufacturing production or the occurrence of catastrophic circumstances such as fire caused through excessive friction/ high belt slippage conditions. Obviously, these situations incur financial losses to companies and in some cases the near loss of the company's main manufacturing plant. Consequently, a satisfactory, viable solution is currently sought by industry to improve on current labour intensive maintenance practices. This paper will present an account of the development of an industrially robust, accurate and repeatable electronic system which continually monitors and indicates the degree of 'slippage' in a 'V' belt drive transmission system and in the circumstance of belt breakage or high belt slippage will enable and control the switching off the drive motor.

Overview of quasi single helicity experiments in reversed field pinches

International Nuclear Information System (INIS)

Martin, P.; Marrelli, L.; Spizzo, G.

2003-01-01

We report the results of an experimental and theoretical project dedicated to the study of Quasi Single Helicity Reversed Field Pinch plasmas. The project has involved several RFP devices and numerical codes. It appears that QSH spectra are a feature common to all the experiments. (author)

Operating point considerations for the Reference Theta-Pinch Reactor (RTPR)

International Nuclear Information System (INIS)

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

1976-01-01

Aspects of the continuing engineering design-point reassessment and optimization of the Reference Theta-Pinch Reactor (RTPR) are discussed. An updated interim design point which achieves a favorable energy balance and involves relaxed technological requirements, which nonetheless satisfy more rigorous physics and engineering constraints, is presented

Significance of thymosin β4 and implication of PINCH-1-ILK-α-parvin (PIP complex in human dilated cardiomyopathy.

Directory of Open Access Journals (Sweden)

Nikolai Sopko

Full Text Available Myocardial remodeling is a major contributor in the development of heart failure (HF after myocardial infarction (MI. Integrin-linked kinase (ILK, LIM-only adaptor PINCH-1, and α-parvin are essential components of focal adhesions (FAs, which are highly expressed in the heart. ILK binds tightly to PINCH-1 and α-parvin, which regulates FA assembly and promotes cell survival via the activation of the kinase Akt. Mice lacking ILK, PINCH or α-parvin have been shown to develop severe defects in the heart, suggesting that these proteins play a critical role in heart function. Utilizing failing human heart tissues (dilated cardiomyopathy, DCM, we found a 2.27-fold (p<0.001 enhanced expression of PINCH, 4 fold for α-parvin, and 10.5 fold (p<0.001 for ILK as compared to non-failing (NF counterparts. No significant enhancements were found for the PINCH isoform PINCH-2 and parvin isoform β-parvin. Using a co-immunoprecipitation method, we also found that the PINCH-1-ILK-α-parvin (PIP complex and Akt activation were significantly up-regulated. These observations were further corroborated with the mouse myocardial infarction (MI and transaortic constriction (TAC model. Thymosin beta4 (Tβ4, an effective cell penetrating peptide for treating MI, was found to further enhance the level of PIP components and Akt activation, while substantially suppressing NF-κB activation and collagen expression--the hallmarks of cardiac fibrosis. In the presence of an Akt inhibitor, wortmannin, we show that Tβ4 had a decreased effect in protecting the heart from MI. These data suggest that the PIP complex and activation of Akt play critical roles in HF development. Tβ4 treatment likely improves cardiac function by enhancing PIP mediated Akt activation and suppressing NF-κB activation and collagen-mediated fibrosis. These data provide significant insight into the role of the PIP-Akt pathway and its regulation by Tβ4 treatment in post-MI.

Grinding Glass Disks On A Belt Sander

Science.gov (United States)

Lyons, James J., III

1995-01-01

Small machine attached to table-top belt sander makes possible to use belt sander to grind glass disk quickly to specified diameter within tolerance of about plus or minus 0.002 in. Intended to be used in place of production-shop glass grinder. Held on driveshaft by vacuum, glass disk rotated while periphery ground by continuous sanding belt.

Development of pulsed high current drivers for fast Z-pinch

International Nuclear Information System (INIS)

Sun Fengju; Qiu Aici; Zeng Zhengzhong; Zeng Jiangtao; Kuai Bin; Yang Hailiang

2006-01-01

It is required that the peak current of high power pulsed drive for fast Z-pinch reaches 60 MA to realize inertial confine fusion (ICF) and high yield (HY). With the conventional technological methods similar to the Z or Saturn apparatus, increasing driver current further is impractical and difficult according to the cost, structure complexity and reliability of the driver, so it is necessary to develop novel fast pulsed high current driver. The present art-of-state and trends of fast Z-pinch driver are summarized, and the typical conceptual designs and technological methods on ICF/HY PRS (plasma radiation source) and destroying-level super X-ray simulators in USA and Russia are outlined, such as HCEI's UGXX1 driver and new Saturn driver based on fast linear transformer driver (FLTD) and novel driver based on fast Marx generator (FMG) with current of 15 MA. The crucial technological problems and requirements to investigate in the future are presented. (authors)

IB-LBM study on cell sorting by pinched flow fractionation.

Science.gov (United States)

Ma, Jingtao; Xu, Yuanqing; Tian, Fangbao; Tang, Xiaoying

2014-01-01

Separation of two categories of cells in pinched flow fractionation(PFF) device is simulated by employing IB-LBM. The separation performances at low Reynolds number (about 1) under different pinched segment widths, flow ratios, cell features, and distances between neighboring cells are studied and the results are compared with those predicted by the empirical formula. The simulation indicates that the diluent flow rate should approximate to or more than the flow rate of particle solution in order to get a relatively ideal separation performance. The discrepancy of outflow position between numerical simulation and the empirical prediction enlarges, when the cells become more flexible. Too short distance between two neighboring cells could lead to cell banding which would result in incomplete separation, and the relative position of two neighboring cells influences the banding of cells. The present study will probably provide some new applications of PFF, and make some suggestions on the design of PFF devices.

X-ray streak camera for observation of tightly pinched relativistic electron beams

International Nuclear Information System (INIS)

Johnson, D.J.

1977-01-01

A pinhole camera is coupled with a Pilot-B scintillator and image-intensified TRW streak camera to study pinched electron beam profiles via observation of anode target bremsstrahlung. Streak intensification is achieved with an EMI image intensifier operated at a gain of up to 10 6 which allows optimizing the pinhole configuration so that resolution is simultaneously limited by photon-counting statistics and pinhole geometry. The pinhole used is one-dimensional and is fabricated by inserting uranium shims with hyperbolic curved edges between two 5-cm-thick lead blocks. The loss of spatial resolution due to the x-ray transmission through the perimeter of the pinhole is calculated and a streak photograph of a Gamble I pinched beam interacting with a brass anode is presented

Observation of Electron Energy Pinch in HT-7 ICRF Heated Plasmas

International Nuclear Information System (INIS)

Ding Siye; Wan Baonian; Ti Ang; Zhang Xinjun; Liu Zixi; Qian Jinping; Zhong Guoqiang; Duan Yanmin; Wang Lu

2014-01-01

Inward energy transport (pinch phenomenon) in the electron channel is observed in HT-7 plasmas using off-axis ion cyclotron resonance frequency (ICRF) heating. Experimental results and power balance transport analysis by TRANSP code are presented in this article. With the aids of GLF23 and Chang-Hinton transport models, which predict energy diffusivity in experimental conditions, the estimated electron pinch velocity is obtained by experimental data and is found reasonably comparable to the results in the previous study, such as Song on Tore Supra. Density scanning shows that the energy convective velocity in the electron channel has a close relation to density scale length, which is qualitatively in agreement with Wang's theoretical prediction. The parametric dependence of electron energy convective velocity on plasma current is still ambiguous and is worthy of future research on EAST. (magnetically confined plasma)

The Magpie dense z-pinch project

International Nuclear Information System (INIS)

Chittenden, J.; Choi, P.; Mitchell, I.; Dangor, A.E.; Haines, M.G.

1990-01-01

The authors present a design study on the Mega Ampere Generator for Plasma Implosion Experiments (MAGPIE), a project currently under construction at Imperial College London, to study radiative collapse of a dense Z-pinch plasma created from a 20 um diameter cryogenic hydrogen fiber. The 2 TW generator is composed of four individual 2.4 MV Marx banks of the HERMES III type design with a maximum stored energy of 336 kJ. They drive four 5 ohm Pulse Forming Lines which are combined into a single 1.25 MA in 150 ns to a 150 nH load

Integration thermal processes through Pinch technology

International Nuclear Information System (INIS)

Rios H, Carlos Mario; Grisales Rincon, Rogelio; Cardona, Carlos Ariel

2004-01-01

This paper presents the techniques of heat integration used for process optimization, their fortresses and weaknesses during the implementation in several specific process are also discussed. It is focused to the pinch technology, explaining algorithms for method applications in the industry. The paper provides the concepts and models involved in different types of commercial software applying this method for energy cost reduction, both in design of new plants and improve of old ones. As complement to benefits of the energy cost reduction it is analysed other favorable aspects of process integration, as the emissions waste reduction and the combined heat end power systems

Colors of Inner Disk Classical Kuiper Belt Objects

Science.gov (United States)

Romanishin, W.; Tegler, S. C.; Consolmagno, G. J.

2010-07-01

We present new optical broadband colors, obtained with the Keck 1 and Vatican Advanced Technology telescopes, for six objects in the inner classical Kuiper Belt. Objects in the inner classical Kuiper Belt are of interest as they may represent the surviving members of the primordial Kuiper Belt that formed interior to the current position of the 3:2 resonance with Neptune, the current position of the plutinos, or, alternatively, they may be objects formed at a different heliocentric distance that were then moved to their present locations. The six new colors, combined with four previously published, show that the ten inner belt objects with known colors form a neutral clump and a reddish clump in B-R color. Nonparametric statistical tests show no significant difference between the B-R color distribution of the inner disk objects compared to the color distributions of Centaurs, plutinos, or scattered disk objects. However, the B-R color distribution of the inner classical Kuiper Belt Objects does differ significantly from the distribution of colors in the cold (low inclination) main classical Kuiper Belt. The cold main classical objects are predominately red, while the inner classical belt objects are a mixture of neutral and red. The color difference may reveal the existence of a gradient in the composition and/or surface processing history in the primordial Kuiper Belt, or indicate that the inner disk objects are not dynamically analogous to the cold main classical belt objects.

COLORS OF INNER DISK CLASSICAL KUIPER BELT OBJECTS

International Nuclear Information System (INIS)

Romanishin, W.; Tegler, S. C.; Consolmagno, G. J.

2010-01-01

We present new optical broadband colors, obtained with the Keck 1 and Vatican Advanced Technology telescopes, for six objects in the inner classical Kuiper Belt. Objects in the inner classical Kuiper Belt are of interest as they may represent the surviving members of the primordial Kuiper Belt that formed interior to the current position of the 3:2 resonance with Neptune, the current position of the plutinos, or, alternatively, they may be objects formed at a different heliocentric distance that were then moved to their present locations. The six new colors, combined with four previously published, show that the ten inner belt objects with known colors form a neutral clump and a reddish clump in B-R color. Nonparametric statistical tests show no significant difference between the B-R color distribution of the inner disk objects compared to the color distributions of Centaurs, plutinos, or scattered disk objects. However, the B-R color distribution of the inner classical Kuiper Belt Objects does differ significantly from the distribution of colors in the cold (low inclination) main classical Kuiper Belt. The cold main classical objects are predominately red, while the inner classical belt objects are a mixture of neutral and red. The color difference may reveal the existence of a gradient in the composition and/or surface processing history in the primordial Kuiper Belt, or indicate that the inner disk objects are not dynamically analogous to the cold main classical belt objects.

Speed Controlled Belt Conveyors: Drives and Mechanical Considerations

Directory of Open Access Journals (Sweden)

BEBIC, M. Z.

2018-02-01

Full Text Available The paper presents variable speed belt conveyor system where the reference speed is changed in order to achieve improved energy efficiency of operation. The recorded measurements show that belt tension varies within the same limits as under constant speed operation. These results introduce a new insight of the present state of the art in variable speed belt conveyor drives. The system is realized with remote control from the control center on an open pit mine. The structure of the multi-motor drive system of a single conveyor, as well as of the network-based control system distributed among belt conveyor stations and the control center are shown. Speed control of a belt conveyor system is organized to provide better utilization of the available material cross section on the belt and reduced electrical energy consumption of the drive. The experimental results obtained on the system prove that, under existing constraints, the applied algorithm has not introduced additional stress to the belt or mechanical assemblies during acceleration and deceleration processes, while providing higher energy efficiency of operation.

Timing belt in power transmission and conveying system

Directory of Open Access Journals (Sweden)

Domek Grzegorz

2018-01-01

Full Text Available This paper presents the problem of phenomena occurring at the contact of a timing belt and a pulley. Depending on a belt size range these phenomena differ significantly. There is no indication as to what solutions are optimal for drive belts. The analysis of the coupling process and performance tests have shown that the drive belt should have a cord of very good mechanical properties and its raceway side should be made from the material of a low friction coefficient against the pulley material. A flat belt in power transmission and conveying systems cooperates with several elements consisting of timing pulleys, tensioners or guiding rails. In gear with timing belts they depend strongly on characteristics of the process as well as the type of friction. In recent constructions, producers of timing belts are very much concerned about achieving as much slippery surface as possible. The work describes the problem of friction on different surfaces as well as its influence on gear lifetime. Research results confirm that on many surfaces bigger coefficient of friction is expected.

Investigation of intense XUV emission of nitrogen-puff Z-pinch with small energy input

International Nuclear Information System (INIS)

Raus, J.; Krejci, A.; Piffl, V.

1992-01-01

Light elements like nitrogen or carbon are suggested as optimum working media for small Z-pinches (several kJ energy input). It is shown that such elements can be ionized up to K-shell ionization stages not only in hot-spots, but also in the bulk plasma. The yield of nitrogen K-shell radiation (about 10 J/shot) is therefore substantially higher than that of the conventionally used neon. In addition to pinch physics and radiation dynamics, such radiation could be of interest for applications in the 'water window' spectral region. (author) 1 tab., 4 figs., 8 refs

Stability analysis of sharp-boundary Vlasov-fluid screw-pinch equilibria

International Nuclear Information System (INIS)

Lewis, H.R.; Turner, L.

1975-01-01

The Vlasov-fluid model is being used to study the linear stability of sharp-boundary screw pinches numerically. The numerical method appears to work well, and some preliminary results are reported. The sharp-boundary calculation is useful for gaining insight and for comparing with known MHD results. (auth)

Plasma-wall interaction and locked modes in the toroidal pinch experiment TPE-RX reversed-field pinch

International Nuclear Information System (INIS)

Pasqualini, D.; Martin, P.; Koguchi, H.; Yagi, Y.; Hirano, Y.; Sakakita, H.; Spizzo, G.

2006-01-01

The MHD instabilities that sustain the reversed-field pinch (RFP) configuration tend to phase-lock together and also to wall-lock, forming a bulging of the plasma column, called 'locked mode'. This phenomenon is of particular interest, since the locked mode causes a larger plasma resistivity, plasma cooling, and, in some cases, anomalous discharge termination. Up to now, studies of the locked mode have been focused on m=1 modes (being m the poloidal mode number). In this Letter we show that m=0 modes also play a role, based on the cross-check between magnetic spectra and toroidally resolved D α array measurements. (author)

An investigation of transient pressures and plasma properties in a pinched plasma column. M.S. Thesis

Science.gov (United States)

Stover, E. K.; York, T. M.

1971-01-01

The transient pinched plasma column generated in a linear Z-pinch was studied experimentally and analytically. The plasma column was investigated experimentally with several plasma diagnostics; they were: a rapid response pressure transducer, a magnetic field probe, a voltage probe, and discharge luminosity. Axial pressure profiles on the discharge chamber axis were used to identify three characteristic regions of plasma column behavior: (1) strong axial pressure asymmetry noted early in plasma column lifetime, (2) followed by plasma heating in which there is a rapid rise in static pressure, and (3) a slight decrease static pressure before plasma column breakup. Plasma column lifetime was approximately 5 microseconds. The axial pressure asymmetry was attributed to nonsimultaneous pinching of the imploding current sheet along the discharge chamber axis. The rapid heating could be attributed in part to viscous effects introduced by radial gradients in the axial streaming velocity.

The effect of sheared axial flow on nonlinear Z-pinch dynamics

International Nuclear Information System (INIS)

Kassapakis, N.

2000-01-01

A two dimensional Eulerian fluid code has been used to study three problems related to Z-pinch and laser produced plasmas. a) The nonlinear evolution of a localised m=0 MHD mode neck is studied in order to extract some scaling laws for the size and form of the artificial neck. We examine whether the ubiquitous m=0 instability could be beneficially used to assist in the formation of a transient localised dense plasma. The results obtained were in satisfactory agreement with experiments and other theoretical work where available. b) The development of the m=0 instability on a Z-pinch although beneficial in the previous case, is detrimental from a stability point of view and thus to the utilisation of the device as a fusion reactor by itself. This is because the timescales of the instability development are faster than the confinement time needed for fusion to occur. Sheared axial flow is a proposed mechanism for the non-linear saturation of this particular instability. Indeed the linear growth rate also can be substantially reduced. It is hoped that it can inhibit the growth of the instabilities or at least delay their development sufficiently for fusion to take place. The numerical study of the effect of sheared axial flow on the nonlinear dynamics of the Z-pinch carried out, demonstrates that sheared flow with velocity u z z >4 Alfven speed other modes, of the Kelvin-Helmholtz type, are excited which take over from the fastest growing mode in the static case. c) The expansion of the ablated plasma in laser-solid interactions is an important phenomenon for a plethora of reasons one of which is ICF. The simulations were in direct agreement with previous experimental work regarding the bulk properties of the ablation surface. They also provided justification for some assumptions made during the analysis of the observations and helped to confirm the calibration of the diagnostics timewise. The most striking feature of the experiments, namely the density dip on the

Conveyor belt weigher using a nuclear technique

International Nuclear Information System (INIS)

Magal, B.S.

1976-01-01

Principles of operation of different types of continuous conveyor belt weighing machines developed for use in factories for bulk weighing of material on conveyor belts without interupting the material flow, are briefly mentioned. The design of nuclear weighing scale making use of the radiation absorption property of the material used is described in detail. The radiation source, choice of the source, detector and geometry of such a weighing scale are discussed. The nucleonic belt weigher is compared with the gravimetric belt weigher system. The advantages of the nuclear system are pointed out. The assembly drawing of the electronics, calibration procedure and performance evaluation are given. (A.K.)

Importance of radial profiles in spectroscopic diagnostics applied to the EXTRAP-T2R reversed-field pinch

OpenAIRE

Gravestijn, Bob

2003-01-01

The determination of the plasma confinement propertiesdemand data as the electron temperature, the ionic and electrondensity profiles and the radiative emissivity profiles. Thefocus of this thesis is the importance of radial profiles inspectroscopic diagnostics applied to the EXTRAP-T2Rreversed-field pinch. EXTRAP-T2R is a resistive shell reversed-field pinch with amagnetic field shell penetration time much longer than therelaxation cycle time scale. Significant improvements inconfinement pro...

Crossed-swords, capsule-pinch technique for capsulotomy in pediatric and/or loose lens cataract extraction.

Science.gov (United States)

Snyder, Michael E; Lindsell, Luke B

2010-02-01

Puncturing the anterior capsule in a patient with a very soft lens, an elastic capsule, and/or deficient zonular countertraction can be challenging even with a sharp needle or blade. The crossed-swords, capsule-pinch technique capitalizes on opposing forces from 2 needles directed toward each other with a "pinch" of the capsule between their tips. This affords a controlled and facile puncture of the capsule without creating stress on the zonules or anteroposterior displacement of the lens. Copyright 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Generation and focusing of intense ion beams with an inverse pinch ion diode

International Nuclear Information System (INIS)

Hashimoto, Yoshiyuki; Sato, Morihiko; Yatsuzuka, Mitsuyasu; Nobuhara, Sadao

1992-01-01

Generation and focusing of ion beams using an inverse pinch ion diode with a flat anode has been studied. The ion beams generated with the inverse pinch ion diode were found to be focused at 120 mm from the anode by the electrostatic field in the diode. The energy and maximum current density of the ion beams were 180 keV and 420 A/cm 2 , respectively. The focusing angle of the ion beams was 4.3deg. The beam brightness was estimated to be 1.3 GW/cm 2 ·rad 2 . The focusing distance of the ion beams was found to be controllable by changing the diameters of the anode and cathode. (author)

Z-pinch driven inertial confinement fusion target physics research at Sandia National Laboratories

International Nuclear Information System (INIS)

Leeper, R.J.; Alberts, T.E.; Asay, J.R.

2001-01-01

Three hohlraum concepts are being pursued at Sandia National Laboratories (SNL) to investigate the possibility of using pulsed power driven magnetic implosions (z-pinches) to drive high gain targets capable of yields in the range of 200-1000 MJ. This research is being conducted on SNL's Z facility that is capable of driving peak currents of 20 MA in z-pinch loads producing implosion velocities as high as 7.5x10 7 cm/s, x-ray energies approaching 2 MJ, and x-ray powers exceeding 200 TW. This paper will discuss each of these hohlraum concepts and will overview the experiments that have been conducted on these systems to date. (author)

HERSCHEL -RESOLVED OUTER BELTS OF TWO-BELT DEBRIS DISKS—EVIDENCE OF ICY GRAINS

Energy Technology Data Exchange (ETDEWEB)

Morales, F. Y.; Bryden, G.; Werner, M. W.; Stapelfeldt, K. R., E-mail: Farisa@jpl.nasa.gov [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

2016-11-01

We present dual-band Herschel /PACS imaging for 59 main-sequence stars with known warm dust ( T {sub warm} ∼ 200 K), characterized by Spitzer . Of 57 debris disks detected at Herschel wavelengths (70 and/or 100 and 160 μ m), about half have spectral energy distributions (SEDs) that suggest two-ring disk architectures mirroring that of the asteroid–Kuiper Belt geometry; the rest are consistent with single belts of warm, asteroidal material. Herschel observations spatially resolve the outer/cold dust component around 14 A-type and 4 solar-type stars with two-belt systems, 15 of which for the first time. Resolved disks are typically observed with radii >100 AU, larger than expected from a simple blackbody fit. Despite the absence of narrow spectral features for ice, we find that the shape of the continuum, combined with resolved outer/cold dust locations, can help constrain the grain size distribution and hint at the dust’s composition for each resolved system. Based on the combined Spitzer /IRS+Multiband Imaging Photometer (5-to-70 μ m) and Herschel /PACS (70-to-160 μ m) data set, and under the assumption of idealized spherical grains, we find that over half of resolved outer/cold belts are best fit with a mixed ice/rock composition. Minimum grain sizes are most often equal to the expected radiative blowout limit, regardless of composition. Three of four resolved systems around the solar-type stars, however, tend to have larger minimum grains compared to expectation from blowout ( f {sub MB} = a {sub min}/ a {sub BOS} ∼ 5). We also probe the disk architecture of 39 Herschel -unresolved systems by modeling their SEDs uniformly, and find them to be consistent with 31 single- and 8 two-belt debris systems.

Instability study during implosion in the Tupa Theta-Pinch

International Nuclear Information System (INIS)

Kayama, M.E.; Boeckelmann, H.K.

1986-01-01

The importance of instabilities which occur during plasma heating in a Theta Pinch, in the implosion phase, is analysed. The plasma diagnostic was done by ultrafast photography and diamagnetic probe. The implosion time and the current layer thickness were calculated using a hybrid code for plasma simulation. The theoretical data were compared with the experimental ones. (M.C.K.) [pt

Physics of the dense Z-pinch in theory and in experiment with application to fusion reactor

Energy Technology Data Exchange (ETDEWEB)

Haines, M.G. (Imperial Coll. of Science and Technology, London (UK). Blackett Lab.)

1982-01-01

A new generation of Z-pinches employing high voltage, high current pulsed lines as power sources produce dense hot plasmas with enhanced stability properties. Three methods of Z-pinch formation are currently in use: (1) cylindrical collapse and compression of a pre-ionised gas; (2) laser initiation and Joule heating of a gas embedded pinch, and (3) hollow gas puff and subsequent collapse to the axis. The first two experimental conditions are relevant for fusion. A calculation of energy balance for satisfying Lawson conditions with axial and radial energy losses and radiation loss shows that a current of approximately 10/sup 6/ A and a line density of 6 x 10/sup 18/ m/sup -1/ are required. This leads to two coincidences of physical quantities that are very favourable for controlled fusion. The first is that at this line density and under pressure balance the ratio of the ion Larmor radius to pinch is of order 1 so that a marked stabilisation of the configuration is expected. The second coincidence is that the current is only just below the Pease-Braginskii limit; this will permit the possibility or radiative collapse to attain the high density (approximately 4 x 10/sup 27/ m/sup -3/) and small radius (approximately 20 ..mu..m) required for a compact (0.1 m long) discharge.

Compliance with Seat Belt Use in Makurdi, Nigeria: An ...

African Journals Online (AJOL)

Background: Seat belts are designed to reduce injuries due to road crash among vehicle occupants. Aims: This study aims to determine the availability of seat belt in vehicles and compliance with seat belt use among vehicle occupants. Materials and methods: This was a 24‑h direct observational study of seat belt usage ...

Global properties of ohmically heated reversed-field pinches

International Nuclear Information System (INIS)

Gerwin, R.A.

The simultaneous requirements of power balance and pressure balance have been considered. The treatment generalizes the Pease-Braginskii pinch current limit by including toroidal magnetic field, anomalous resistivity, nonradiative losses, and time-dependent fields. The rise of the temperature to a state of power balance proves to be amenable to a very simple and unified description. Finally, the practical parameter windows implied by the joint action of power balance and pressure balance are displayed

Prospects for fusion applications of reversed-field pinches

International Nuclear Information System (INIS)

Bathke, C.G.; Krakowski, R.A.; Hagenson, R.L.

1985-01-01

The applicability of the Reversed-Field Pinch (RFP) as a source of fusion neutrons for use in developing key fusion nuclear technologies is examined. This Fusion Test Facility (FTF) would emphasize high neutron wall loading, small plasma volume, low fusion and driver powers, and steady-state operation. Both parametric tradeoffs based on present-day physics understanding and a conceptual design based on an approx.1-MW/m 2 (neutron) driven operation are reported. 10 refs

Final Technical Report, DOE Grant DE-FG02-98ER54496, Physics of High-Energy-Density X Pinch Plasmas

International Nuclear Information System (INIS)

Hammer, David

2008-01-01

Abstract for the Final Technical Report, DOE Grant DE-FG02-98ER54496 An X-pinch plasma is produced by driving a high current (100-500 kiloamperes) through two or more fine wires that cross and touch at a point, forming an X in the case of two wires. The wires explode because of the high current, and then the resulting plasma is imploded radially inward by the magnetic field from the current. When the imploding material briefly stagnates at very small radius and high density, an intense burst of x-rays is produced and the plasma disassembles as rapidly as it imploded. When this project began, we could confidently state that at its minimum radius, X pinch plasmas made from such materials as titanium and molybdenum might be as hot as 10,000,000 K and had densities almost as high as the solid wire density, but their X-ray pulse durations were below one billionth of a second. We could also say that the X pinch was useful for point-projection imaging of rapidly changing objects, such as exploding wires, with high resolution, indicative of a very small X-ray source spot size. We can now confidently say that X-pinch plasma temperatures at the moment of the X-ray burst are 10-25 million K in titanium, molybdenum and several other wire X-pinches based upon the spectrum of emitted X-rays in the radiation burst. By the same means, as well as from the penetration of X-rays through the dense plasma, we know that ion densities are close to or higher than one-tenth of the density of the original (solid) wire material in molybdenum and a few other X-pinch plasmas. Furthermore, using the diffraction of X-rays radiated by the X-pinch when it reaches minimum radius, we have determined that the x-ray source size is about 1 thousandth of a millimeter for such wire materials as molybdenum and niobium, while it is 2-10 times larger for tungsten, titanium and aluminum wires. Finally, using a very high speed X-ray imaging 'streak camera,' we have determined that X pinch X-ray pulses can be

Infrared emission as a diagnostic for a collapsing gas shell < pinch

International Nuclear Information System (INIS)

Jones, L.A.; Kania, D.R.; Shephard, R.L.; Maestas, M.D.

1985-01-01

The shape and absolute intensity of the infrared emission as a function of wavelength can yield information about the conditions in a plasma. This diagnostic technique has been reviewed by Zwicker, who gives several examples of its application to low density plasmas. They have applied this diagnostic, for the first time, to a high density (∼ 10 20 cm -3 ) plasma, a collapsing gas (argon) shell Z pinch. Using a fast Au doped Ge detector and infrared notch filters they have scanned the emitted spectrum from ∼ 0.5 to 8.2 μm with 1-ns time resolution. This spectral range encompasses the optically thin-to-thick transition as well as the plasma frequency at the time of peak compression. The authors will present this data along with an interpretation which allows us to follow the development of the pinched column during the thermalization stage

Enclosed belts in the ascendancy

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-03-15

Although there will always be a place for traditional overland belt conveyors, enclosed belt systems are increasingly being specified where environmental protection assumes high priority or where there is a need to protect material from the weather. The article reports on recent conveyor projects such as: an MRC cable Belt in a 6.4 km system to carry coal in the Appalachian Mountains; a $40 m contract awarded to FL Smidth to supply an integrated coal handling system to LILIAMA in Vietnam and other contracts to handle coal for India's Coastal Gujarat Power; and a contract awarded to Bateman Engineered Technologies to supply a 7 km Japan Pipe Conveyor for a coal power station in Brazil. 3 photos.

Intelligent Belt Conveyor Monitoring and Control

NARCIS (Netherlands)

Pang, Y.

2010-01-01

Belt conveyors have been used worldwide in continuous material transport for about 250 years. Traditional inspection and monitoring of large-scale belt conveyors focus on individual critical components and response to catastrophic system failures. To prevent operational problems caused by the lack

Handbook Timing Belts Principles, Calculations, Applications

CERN Document Server

Perneder, Raimund

2012-01-01

Timing belts offer a broad range of innovative drivetrain solutions; they allow low-backlash operation in robot systems, they are widely used in automated processes and industrial handling involving highly dynamic start-up loads, they are low-maintenance solutions for continuous operation applications, and they can guarantee exact positioning at high operating speeds. Based on his years of professional experience, the author has developed concise guidelines for the dimensioning of timing belt drives and presents proven examples from the fields of power transmission, transport and linear transfer technology. He offers definitive support for dealing with and compensating for adverse operating conditions and belt damage, as well as advice on drive optimization and guidelines for the design of drivetrain details and supporting systems. All market-standard timing belts are listed as brand neutral. Readers will discover an extensive bibliography with information on the various manufacturers and their websites. This...

Dynamics of sausage instabilities of a gas-puff Z-pinch

International Nuclear Information System (INIS)

Sopkin, Yu.V.; Dorokhin, L.A.; Koshelev, K.N.; Sidelnikov, Yu.V.

1991-01-01

The early stage of the sausage instability in a gas-puff Z-pinch has been registered in VUV and soft X-rays with a 10 ns framing camera. We hypothesize that the rings of plasma expanding from the sausage instability enable an alternative current path to dominate the formation of 'micropinches'. (orig.)

A spectroscopic study of radiation produced in a theta-pinch

International Nuclear Information System (INIS)

Trigueiros, A.; Machida, M.; Pagan, C.J.B.

1988-01-01

Preliminary results of the analysis of the spectra of four times ionized Krypton, Kr-V, are presented. 28 transitions were classified and for five of then the classification is new. We also present the UNICAMP theta-pinch for the study of highly ionized atoms. This device is now in testing. (author) [pt

Draws on a relativistic pinch with a longitudinal magnetic field

International Nuclear Information System (INIS)

Trubnikov, B.A.

1991-01-01

The problems of draws on a relativistic pinch with longitudinal magnetic field are discussed. The absence of collisions promoting the energy exchange between different degrees of particle freedom is assumed. The calculations are conducted using the ideal relativistic anisotropic magnetic hydrodynamics equations. The spectrum of particles accelerated in the draws, is determined

Integration of solar thermal for improved energy efficiency in low-temperature-pinch industrial processes

International Nuclear Information System (INIS)

Atkins, Martin J.; Walmsley, Michael R.W.; Morrison, Andrew S.

2010-01-01

Solar thermal systems have the potential to provide renewable industrial process heat and are especially suited for low pinch temperature processes such as those in the food, beverage, and textile sectors. When correctly integrated within an industrial process, they can provide significant progress towards both increased energy efficiency and reduction in emissions. However, the integration of renewable solar energy into industrial processes presents a challenge for existing process integration techniques due to the non-continuous nature of the supply. A thorough pinch analysis study of the industrial process, taking in to account non-continuous operating rates, should be performed to evaluate the utility demand profile. Solar collector efficiency data under variable climatic conditions should also be collected for the specific site. A systematic method of combining this information leads to improved design and an optimal operating strategy. This approach has been applied to a New Zealand milk powder plant and benefits of several integration strategies, including mass integration, are investigated. The appropriate placement of the solar heat is analogous to the placement of a hot utility source and an energy penalty will be incurred when the solar thermal system provides heat below the pinch temperature.

Integration of solar thermal for improved energy efficiency in low-temperature-pinch industrial processes

Energy Technology Data Exchange (ETDEWEB)

Atkins, Martin J.; Walmsley, Michael R.W.; Morrison, Andrew S. [Energy Research Group, School of Science and Engineering, University of Waikato, Private Bag 3105, Hamilton 3240 (New Zealand)

2010-05-15

Solar thermal systems have the potential to provide renewable industrial process heat and are especially suited for low pinch temperature processes such as those in the food, beverage, and textile sectors. When correctly integrated within an industrial process, they can provide significant progress towards both increased energy efficiency and reduction in emissions. However, the integration of renewable solar energy into industrial processes presents a challenge for existing process integration techniques due to the non-continuous nature of the supply. A thorough pinch analysis study of the industrial process, taking in to account non-continuous operating rates, should be performed to evaluate the utility demand profile. Solar collector efficiency data under variable climatic conditions should also be collected for the specific site. A systematic method of combining this information leads to improved design and an optimal operating strategy. This approach has been applied to a New Zealand milk powder plant and benefits of several integration strategies, including mass integration, are investigated. The appropriate placement of the solar heat is analogous to the placement of a hot utility source and an energy penalty will be incurred when the solar thermal system provides heat below the pinch temperature. (author)

Energetic electrons in the inner belt in 1968

Energy Technology Data Exchange (ETDEWEB)

West, Jr, H I; Buck, R M [California Univ., Livermore (USA). Lawrence Livermore Lab.

1976-07-01

Pitch-angle data were obtained by the Lawrence Livermore Laboratory's scanning, magnetic electron spectrometer on OGO 5 during its traversals of the inner belt in 1968. Data from the five lowest-energy channels 79 to 822 keV, were analyzed. The inner-belt electron injection following two storm periods was observed; the first was the mild storm of 11 June and the second the more intense storms of 31 October and 1 November. Comparisons with other data indicate that only a small Starfish residual (at > 1 MeV) still remained in the heart of the inner belt; hence, the results are indicative of the normal inner belt. The data are discussed in terms of current ideas regarding the source and loss of particles in the inner belt.

Necking down of sausages in current-carrying plasma pinches

International Nuclear Information System (INIS)

Trubnikov, B.A.; Zhdanov, S.K.

1986-01-01

The evolution of long-wave perturbations is shown to be equivalent, for various unstable media, to the dynamics of a gas with a negative adiabatic index γ. This evolution is described (for various values at N) by the quasi-Chaplygin system of equations Several examples of such media are considered, including a ''Chaplygin gas'' (N = 3), drops on a ceiling or ''solitons which have broken'' (N = 0), necks in a current-carrying plasma pinch with a skin effect, for both incompressible and compressible models (N = 2), and the breakup of liquid jets into drops (N = 3/2). A principle for selecting evolutionary solutions corresponding to the absence of perturbations in the limit t → -∞ is formulated. In the cases N = 0 and N = 2, a hodograph transformation reduces system (1) to a magnetostatic equation (ΔA)/sub phi/ = -(4π/c)j/sub phi/ and all the instability modes are equivalent to multipoles of circular currents which are localized on a circle. Exact solutions are given for periodic and isolated (localized) perturbations. The breakup of a medium into distinct blobs, in particular, the rupture of necks in a current-carrying plasma pinch, is demonstrated

An investigation of transient pressure and plasma properties in a pinched plasma column. M.S. Thesis

Science.gov (United States)

Stover, E. K.; York, T. M.

1971-01-01

The transient pinched plasma column generated in a linear Z-pinch was studied experimentally and analytically. The plasma column was investigated experimentally with the following plasma diagnostics: a special rapid response pressure transducer, a magnetic field probe, a voltage probe and discharge luminosity. Axial pressure profiles on the discharge chamber axis were used to identify three characteristic regions of plasma column behavior; they were in temporal sequence: strong axial pressure asymmetry noted early in plasma column lifetime followed by plasma heating in which there is a rapid rise in static pressure and a slight decrease static pressure before plasma column breakup. Plasma column lifetime was approximately 5 microseconds. The axial pressure asymmetry was attributed to nonsimultaneous pinching of the imploding current sheet along the discharge chamber axis. The rapid heating is attributed in part to viscous effects introduced by radial gradients in the axial streaming velocity. Turbulent heating arising from discharge current excitation of the ion acoustic wave instability is also considered a possible heating mechanism.

Effect of plasma formation on electron pinching and microwave emission in a virtual cathode oscillator

Energy Technology Data Exchange (ETDEWEB)

Yatsuzuka, M; Nakayama, M; Nobuhara, S [Himeji Institute of Technology (Japan); Young, D; Ishihara, O [Texas Tech Univ., Lubbock, TX (United States)

1997-12-31

Time and spatial evolutions of anode and cathode plasmas in a vircator diode were observed with a streak camera. A cathode plasma appeared immediately after the rise of a beam current and was followed by an anode plasma typically after about 30 ns. Both plasmas expanded with almost the same speed of order of 104 m/s. The anode plasma was confirmed as a hydrogen plasma with an optical filter for H{sub {beta}} line and study of anode-temperature rise. Electron beam pinching immediately followed by microwave emission was observed at the beam current less than the critical current for diode pinching in the experiment and the simulation. The electron beam current in the diode region is well characterized by the electron space-charge-limited current in bipolar flow with the expanding plasmas between the anode-cathode gap. As a result, electron bombardment produced the anode plasma, which made the electron beam strongly pinched, resulting in virtual cathode formation and microwave emission. (author). 5 figs., 5 refs.

Z-Pinch at extreme energies: Nanofocus of less than 1J. Plasma Focus of 400 J. Gas embedded Z-pinch operating at MA

International Nuclear Information System (INIS)

Pavez Morales, Cristian A

2007-01-01

The work presented in this thesis is in relation with an experimental study developed in three different pulsed plasma generators. Two of them were already operating in the plasma laboratory of the Chilean Nuclear Energy Commission (CCHEN ) at the beginning of this thesis and they are: a) plasma focus PF-40OJ ((880nF, 30kV, 120kA, 400J, 300ns maximum current, dl/dt4x10 11 A/s) which is one of the first plasma focus devices at low energy that produces neutron pulses of fusion and b) the pulsed power generator SPEED-2 (4.1μF equivalent capacity, 300 kV, 4 MA in short circuit, 187 kJ, 400 ns at maximum current, dl/dt∼10 13 A/s) designed to operate in a plasma focus configuration. The third experiment corresponds to a plasma focus device at energy lower than 1J (Nanofocus), which was designed, constructed and characterized during the development of this thesis. The performed work can be summarized in two general aspects: the experimental study of the scaling in plasma focus devices at low energy and the development of a linear Z-pinch configuration using the SPEED-2 generator. In this last situation, a mechanism of preionization was developed in order to create a gas embedded Z-pinch discharge (Deuterium in the case of our experiment) that was conveniently coupled to the electrical characteristics of the generator. In every experiment, the plasma properties were studied (density, dynamics, size, radiation emission) and they reported the state of it. In the plasma focus device PF-40OJ, the electronic density was characterized for discharges in H 2 by using optical refractive techniques, measuring density values in the pinch ∼10 25 m -3 , similar to those reported in plasma focus devices at higher energies. The anisotropy was measured in the distribution of the intensity in the neutron emission for discharges in D 2 using track detector techniques CR-39. A distribution for the neutron flux characterized by an isotropic contribution of 57.5% and also by other

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

Belt design central to conveyor performance

Energy Technology Data Exchange (ETDEWEB)

NONE

2007-07-15

While a conveyor system comprises a complex range of components, it is the belt design which ultimately dictates its core performance and reliability. The complexity of modern systems can be seen by the recent contract awarded to ThyssenKrupp Foerdertechnik (TKF) to supply systems for a new steel plant (including a coking plant and a power plant) to be built in Sepetiba Bay in Brazil. Phoenix has designed the Phoenotec system to protect steel cord conveyor belts. Fenner Dunlop has developed Fenaplast belting with nylon or polyester load-bearing warp and weft yarns for good impact resistance. 2 photos.

Geography of the asteroid belt

Science.gov (United States)

Zellner, B. H.

1978-01-01

The CSM classification serves as the starting point on the geography of the asteroid belt. Raw data on asteroid types are corrected for observational biases (against dark objects, for instance) to derive the distribution of types throughout the belt. Recent work on family members indicates that dynamical families have a true physical relationship, presumably indicating common origin in the breakup of a parent asteroid.

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

Energy Technology Data Exchange (ETDEWEB)

Hamann, F

2003-12-15

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

Cryogenic deuterium Z-pinch and wire array Z-pinch studies at Imperial College

International Nuclear Information System (INIS)

Haines, M.G.; Aliaga-Rossel, R.; Beg, N.F.

2001-01-01

Z-pinch experiments using cryogenic deuterium fibre loads have been carried out on the MAGPIE generator at currents up to 1.4MA. M=0 instabilities in the corona caused plasma expansion and disruption before the plasma could enter the collisionless Large ion Larmor radius regime. For the last 12 months we have studied Aluminium wire array implosions using laser probing, optical streaks and gated X-ray images. Plasma from the wires in accelerated to the axis as radial plasma streams with uncorrelated m=0 instabilities superimposed. Later in the discharge a global Rayleigh-Taylor (R-T) instability develops. Single and double aluminium and tungsten wire shots were conducted at 150kA. 2-D and 3-D simulations and a heuristic model of wire arrays will be presented along with theories on the combined MHD/R-T instability and sheared axial flow generation by large ion Larmor radius effects. (author)

Cryogenic deuterium Z-pinch and wire array Z-pinch studies at imperial college

International Nuclear Information System (INIS)

Haines, M.G.; Aliaga-Rossel, R.; Beg, F.N.

1999-01-01

Z-pinch experiments using cryogenic deuterium fibre loads have been carried out on the MAGPIE generator at currents up to 1.4MA. M=0 instabilities in the corona caused plasma expansion and disruption before the plasma could enter the collisionless Large ion Larmor radius regime. For the last 12 months we have studied Aluminium wire array implosions using laser probing, optical streaks and gated X-ray images. Plasma from the wires in accelerated to the axis as radial plasma streams with uncorrelated m=0 instabilities superimposed. Later in the discharge a global Rayleigh-Taylor (R-T) instability develops. Single and double aluminium and tungsten wire shots were conducted at 150kA. 2-D and 3-D simulations and a heuristic model of wire arrays will be presented along with theories on the combined MHD/R-T instability and sheared axial flow generation by large ion Larmor radius effects. (author)

Multipoint Thomson scattering system for the EXTRAP Z-pinch experiment

International Nuclear Information System (INIS)

Karlsson, P.

1986-03-01

A Thomson scattering system for simultaneous measurements of the electron temperature and density at three different positions at two different times during a single plasma shot has been developed for the EXTRAP-L1 Z-pinch. The plasma in the present version of EXTRAP-L1 is characterized by densities in the range from 10 21 to 10 22 m -3 , temperatures up to 50 eV and a pinch radius of the order of 1 cm. A spatial resolution down to 3 mm between positions is obtained by imaging the plasma onto an array of quartz optical fibres at the output slit of the spectrometer. Fifteen PM-tubes are used to detect the scattered radiation as well as the background radiation. Due to the relatively dense plasma prevailing in the present version of EXTRAP-L1 the number of scattered photons in large and the photon to electron conversion noise is small. The background radiation is the most important factor limiting the accuracy of the measurements. (author)

Toroidal fusion reactor design based on the reversed-field pinch

International Nuclear Information System (INIS)

Hagenson, R.L.

1978-07-01

The toroidal reversed-field pinch (RFP) achieves gross equilibrium and stability with a combination of high shear and wall stabilization, rather than the imposition of tokamak-like q-constraints. Consequently, confinement is provided primarily by poloidal magnetic fields, poloidal betas as large as approximately 0.58 are obtainable, the high ohmic-heating (toroidal) current densities promise a sole means of heating a D-T plasma to ignition, and the plasma aspect ratio is not limited by stability/equilibrium constraints. A reactor-like plasma model has been developed in order to quantify and to assess the general features of a power system based upon RFP confinement. An ''operating point'' has been generated on the basis of this plasma model and a relatively detailed engineering energy balance. These results are used to generate a conceptual engineering model of the reversed-field pinch reactor (RFPR) which includes a general description of a 750 MWe power plant and the preliminary consideration of vacuum/fueling, first wall, blanket, magnet coils, iron core, and the energy storage/transfer system

Klippen Belt, Flysch Belt and Inner Western Carpathian Paleogene Basin Relations in the Northern Slovakia by Magnetotelluric Imaging

Czech Academy of Sciences Publication Activity Database

Majcin, D.; Bezák, V.; Klanica, Radek; Vozár, J.; Pek, Josef; Bilčík, D.; Telecký, Josef

(2018) ISSN 0033-4553 Institutional support: RVO:67985530 Keywords : magnetotellurics * Western Carpathians * Klippen Belt * Flysch Belt * Inner Carpathian Paleogene Subject RIV: DE - Earth Magnetism, Geodesy, Geography OBOR OECD: Physical geography Impact factor: 1.591, year: 2016

Data processing for elliptical crystal spectrometer used in Z-pinch diagnostic

International Nuclear Information System (INIS)

Li Jing; Xie Weiping; Huang Xianbin; Yang Libing; Cai Hongchun; Xiao Shali

2010-01-01

Elliptical crystal spectrometers are key instruments to detect the line spectra of soft X-rays in Z-pinch diagnostics. This paper deals with the data processing for an elliptical crystal spectrometer. Taking the diagnostic results obtained in a neon gas-puff Z-pinch experiment as an example, the detailed processes, such as changing the optical density to X-ray intensity according a calibrated film response curve, determining the X-ray energy of the measured spectrum using the energy and the order number of scanned point of identified spectral lines, and correcting the intensity of spectrum using the formula given by Henke are discussed. In the Henke's formula, the effect of nonuniform dispersion, integrated reflectivity of crystals and transmission of X-ray filters are considered. The final unfolding results are presented, including the relative intensities of several neon K-shell lines (H α , He α and He β , etc.) given by Lorentz fitting. The relative errors of the spectral intensities are also briefly discussed. (authors)

Capillary Thinning and Pinch-off Dynamics and Printability of Polyelectrolyte Solutions

Science.gov (United States)

Sharma, Vivek; Jimenez, Leidy N.; Dinic, Jelena; Parsi, Nikila

Biological macromolecules like proteins, DNA and polysaccharides, and many industrial polymers, are classified together as polyelectrolytes for in solution, the repeat units in their backbone are decorated with disassociated, charge-bearing ionic groups, surrounded by counter-ions. In diverse applications like inkjet printing, sprayable cosmetics and insecticides, paints and coatings that involve formation of fluid columns or sheets that undergo progressive thinning and pinch-off into drops, the dominant flow within the necking filament is extensional in nature. The extensional rheology response of the charged macromolecular solutions is not as well understood as that of their uncharged counterparts. Here focus on the characterization of capillary thinning and pinch-off dynamics, extensional rheology and printability of two model systems: sodium (polystyrene sulfonate) and poly(acrylic acid) by using dripping-onto-substrate (DoS) rheometry technique. Both the measured extensional relaxation times and the extensional viscosity values show salt- and polymer concentration-dependent behavior that is not expected or anticipated from the typical shear rheology response.

A short-pulse mode for the SPHINX LTD Z-pinch driver

Science.gov (United States)

D'Almeida, Thierry; Lassalle, Francis; Zucchini, Frederic; Loyen, Arnaud; Morell, Alain; Chuvatin, Alexander

2015-11-01

The SPHINX machine is a 6MA, 1 μs, LTD Z-pinch driver at CEA Gramat (France) and primarily used for studying radiation effects. Different power amplification concepts were examined in order to reduce the current rise time without modifying the generator discharge scheme, including the Dynamic Load Current Multiplier (DLCM) proposed by Chuvatin. A DLCM device, capable of shaping the current pulse without reducing the rise time, was developed at CEA. This device proved valuable for isentropic compression experiments in cylindrical geometry. Recently, we achieved a short pulse operation mode by inserting a vacuum closing switch between the DLCM and the load. The current rise time was reduced to ~300 ns. We explored the use of a reduced-height wire array for the Dynamic Flux Extruder in order to improve the wire array compression rate and increase the efficiency of the current transfer to the load. These developments are presented. Potential benefits of these developments for future Z pinch experiments are discussed.

Preliminary results from the flow-through z-pinch experiments: ZaP

International Nuclear Information System (INIS)

Shumlak, U.; Nelson, B.A.; Goilingo, R.P.; Tang, D.; Crawford, E.; Hartog, D.J.D.; Holly, D.J.

1999-01-01

The stabilizing effect of an axial flow on the m = 1 kink instability in z-pinches has been studied numerically by reducing the linearized ideal MHD equations to a one-dimensional eigenvalue equation for the radial displacement. A diffuse z-pinch equilibrium is chosen that is made marginally stable to the m = 0 sausage mode by tailoring the pressure profile. The principal result reveals that a sheared axial flow does stabilize the kink mode when the shear exceeds a threshold value which is inversely proportional to the wavelength of the mode. This threshold value can be satisfied with a peak flow which is less than the Alfven speed for certain wavelengths. Additionally, the m = 0 sausage mode is driven from marginal stability into the stable regime which suggests that the equilibrium pressure profile control can be relaxed. The flow stabilization agrees with experimental observations. The details of the theoretical development will be presented

Physical analysis for designing nested-wire arrays on Z-pinch implosion

International Nuclear Information System (INIS)

Yang Zhenhua; Liu Quan; Ding Ning; Ning Cheng

2005-01-01

Z-pinch experiments have demonstrated that the X-ray power increases 40% with a nested-wire array compared with that with a single-layered wire array. The design of the nested-wire array on Z accelerator is studied through the implosion dynamics and the growth of RT instabilities. The analysis shows that the nested-wire array does not produce more total X-ray radiation energy than the single-layered wire array, but it obviously increases the X-ray power. The radius of the outer array of the nested-wire array could be determined based on the radius of the optimized single-layered. The masses of the outer and inner arrays could be determined by the implosion time of the nested-wire array, which is roughly the same as that of the single-layered wire array. Some suggestions are put forward which may be helpful in the nested-wire array design for Z-pinch experiments. (authors)

On the stability limits of the Pinch-conductor current ratio in Extrap

International Nuclear Information System (INIS)

Lehnert, B.

1987-12-01

A first attempt is made to take the special stability features of the Extrap confinement scheme into account, thereby including kinetic large Larmor radius (LLR) effects. This approach predicts Extrap to be unstable outside a domain defined by a lower and an upper ratio a - /a x is related to the ratio J p /J v between the pinch current J p and the conductor current J v . Stability within the predicted domain seems to agree with so far performed linear and toroidal experiments, and can explain the observed increase in J p /J v and in the plasma temperature, in terms of an increased ratio a - /a x . According to present analysis, an optimum value of the conductor current J v should further exist with respect to pinch equilibrium and stability, as given by the condition a - approx = a x . (author)

Experimental study on gas-puff Z-pinch load characteristics on yang accelerator

International Nuclear Information System (INIS)

Ren Xiaodong; Huang Xianbin; Yang Libing; Dan Jiakun; Duan Shuchao; Zhang Zhaohui; Zhou Shaotong

2010-01-01

A supersonic single-shell gas-puff load has been developed for Z-pinch experiments on 'Yang' accelerator. Using a fast responding pressure probe to measure the supersonic gas flow, impact pressure at different position and plenum pressure were acquired, which were combined with gas dynamics formulas to determine gas pressures and densities. The radial density profile displays that positions of gas shell varies with axial position, and the gas densities on axis increases as the distance from nozzle increases. Integral radial densities indicates that the linear mass density peaks at nozzle exit and decreases as increasing the distance from nozzle. Using single-shell supersonic gas-puff load, Z-pinch implosion experiments were performed on 'Yang' accelerator. Primary analysis of implosion process was presented, and computational trajectories of imploding plasma shell using snowplow model are in agreement with the experimental results. (authors)

14 CFR 125.211 - Seat and safety belts.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Seat and safety belts. 125.211 Section 125... Requirements § 125.211 Seat and safety belts. (a) No person may operate an airplane unless there are available... the airplane who is at least 2 years old; and (2) An approved safety belt for separate use by each...

Study of gas-puff Z-pinches on COBRA

Energy Technology Data Exchange (ETDEWEB)

Qi, N.; Rosenberg, E. W.; Gourdain, P. A.; Grouchy, P. W. L. de; Kusse, B. R.; Hammer, D. A.; Bell, K. S.; Shelkovenko, T. A.; Potter, W. M.; Atoyan, L.; Cahill, A. D.; Evans, M.; Greenly, J. B.; Hoyt, C. L.; Pikuz, S. A.; Schrafel, P. C. [Laboratory of Plasma Studies, Cornell University, Ithaca, New York 14853 (United States); Kroupp, E.; Fisher, A.; Maron, Y. [Weizmann Institute of Science, Rehovot 76100 (Israel)

2014-11-15

Gas-puff Z-pinch experiments were conducted on the 1 MA, 200 ns pulse duration Cornell Beam Research Accelerator (COBRA) pulsed power generator in order to achieve an understanding of the dynamics and instability development in the imploding and stagnating plasma. The triple-nozzle gas-puff valve, pre-ionizer, and load hardware are described. Specific diagnostics for the gas-puff experiments, including a Planar Laser Induced Fluorescence system for measuring the radial neutral density profiles along with a Laser Shearing Interferometer and Laser Wavefront Analyzer for electron density measurements, are also described. The results of a series of experiments using two annular argon (Ar) and/or neon (Ne) gas shells (puff-on-puff) with or without an on- (or near-) axis wire are presented. For all of these experiments, plenum pressures were adjusted to hold the radial mass density profile as similar as possible. Initial implosion stability studies were performed using various combinations of the heavier (Ar) and lighter (Ne) gasses. Implosions with Ne in the outer shell and Ar in the inner were more stable than the opposite arrangement. Current waveforms can be adjusted on COBRA and it was found that the particular shape of the 200 ns current pulse affected on the duration and diameter of the stagnated pinched column and the x-ray yield.

Belt Conveyor Dynamic Characteristics and Influential Factors

Directory of Open Access Journals (Sweden)

Junxia Li

2018-01-01

Full Text Available This paper uses the Kelvin-Voigt viscoelastic model to establish the continuous dynamic equations for tail hammer tension belt conveyors. The viscoelastic continuity equations are solved using the generalized coordinate method. We analyze various factors influencing longitudinal vibration of the belt conveyor by simulation and propose a control strategy to limit the vibration. The proposed approach and control strategy were verified by several experimental researches and cases. The proposed approach provides improved accuracy for dynamic design of belt conveyors.

Preliminary experimental results of tungsten wire-array Z-pinches on primary test stand

Energy Technology Data Exchange (ETDEWEB)

Huang, Xian-Bin; Zhou, Shao-Tong; Dan, Jia-Kun; Ren, Xiao-Dong, E-mail: amosrxd@163.com; Wang, Kun-Lun; Zhang, Si-Qun; Li, Jing; Xu, Qiang; Cai, Hong-Chun; Duan, Shu-Chao; Ouyang, Kai; Chen, Guang-Hua; Ji, Ce; Wei, Bing; Feng, Shu-Ping; Wang, Meng; Xie, Wei-Ping; Deng, Jian-Jun [Key Laboratory of Pulsed Power, Institute of Fluid Physics, China Academy of Engineering Physics, P.O. Box 919-108, Mianyang, Sichuan 621999 (China); Zhou, Xiu-Wen; Yang, Yi [Research Center of Laser Fusion, China Academy of Engineering Physics, P.O. Box 919-987, Mianyang, Sichuan 621999 (China)

2015-07-15

The Primary Test Stand (PTS) developed at the China Academy of Engineering Physics is a 20 TW pulsed power driver, which can deliver a ∼10 MA, 70 ns rise-time (10%–90%) current to a short-circuit load and has important applications in Z-pinch driven inertial confinement fusion and high energy density physics. Preliminary results of tungsten wire-array Z-pinch experiments on PTS are presented. The load geometries investigated include 15-mm-tall cylindrical single and nested arrays with diameter ranging from 13 mm to 30 mm, consisting of 132–300 tungsten wires with 5–10 μm in diameter. Multiple diagnostics were fielded to characterize the x-ray radiation from wire-array Z pinches. The x-ray peak power (∼50 TW) and total radiated energy (∼500 kJ) were obtained from a single 20-mm-diam array with 80-ns stagnation time. The highest x-ray peak power up to 80 TW with 2.4 ns FWHM was achieved by using a nested array with 20-mm outer diameter, and the total x-ray energy from the nested array is comparable to that of single array. Implosion velocity estimated from the time-resolved image measurement exceeds 30 cm/μs. The detailed experimental results and other findings are presented and discussed.

Space Weather Effects in the Earth's Radiation Belts

Science.gov (United States)

Baker, D. N.; Erickson, P. J.; Fennell, J. F.; Foster, J. C.; Jaynes, A. N.; Verronen, P. T.

2018-02-01

The first major scientific discovery of the Space Age was that the Earth is enshrouded in toroids, or belts, of very high-energy magnetically trapped charged particles. Early observations of the radiation environment clearly indicated that the Van Allen belts could be delineated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. The energy distribution, spatial extent and particle species makeup of the Van Allen belts has been subsequently explored by several space missions. Recent observations by the NASA dual-spacecraft Van Allen Probes mission have revealed many novel properties of the radiation belts, especially for electrons at highly relativistic and ultra-relativistic kinetic energies. In this review we summarize the space weather impacts of the radiation belts. We demonstrate that many remarkable features of energetic particle changes are driven by strong solar and solar wind forcings. Recent comprehensive data show broadly and in many ways how high energy particles are accelerated, transported, and lost in the magnetosphere due to interplanetary shock wave interactions, coronal mass ejection impacts, and high-speed solar wind streams. We also discuss how radiation belt particles are intimately tied to other parts of the geospace system through atmosphere, ionosphere, and plasmasphere coupling. The new data have in many ways rewritten the textbooks about the radiation belts as a key space weather threat to human technological systems.

Measurement of emission diameter as a function of time on foam z- pinch plasmas

International Nuclear Information System (INIS)

Lazier, S.E.; Barber, T.L.; Derzon, M.S.; Kellogg, J.W.

1996-01-01

We have developed a streaked imaging capability to make time-resolved measurements of the emission size for low density foam z-pinches. By lens coupling visible emission from the z-pinch target to an array of fiber optics we obtained the emission profile in the visible as a function of time with radial resolution of 300 μm. To measure the emission at temperatures greater than ∼40 eV the source was slit-imaged or pin-hole imaged onto an x-ray filtered scintillator. Non-uniformities in both visible and x-ray emission were observed. We describe the diagnostics, the image unfold process, and results from the instrument for both visible and x-ray measurements

A solvable self-similar model of the sausage instability in a resistive Z pinch

International Nuclear Information System (INIS)

Lampe, M.

1991-01-01

A solvable model is developed for the linearized sausage mode within the context of resistive magnetohydrodynamics. The model is based on the assumption that the fluid motion of the plasma is self-similar, as well as several assumptions pertinent to the limit of wavelength long compared to the pinch radius. The perturbations to the magnetic field are not assumed to be self-similar, but rather are calculated. Effects arising from time dependences of the z-independent perturbed state, e.g., current rising as t α , Ohmic heating, and time variation of the pinch radius, are included in the analysis. The formalism appears to provide a good representation of ''global'' modes that involve coherent sausage distortion of the entire cross section of the pinch, but excludes modes that are localized radially, and higher radial eigenmodes. For this and other reasons, it is expected that the model underestimates the maximum instability growth rates, but is reasonable for global sausage modes. The net effect of resistivity and time variation of the unperturbed state is to decrease the growth rate if α approx-lt 1, but never by more than a factor of about 2. The effect is to increase the growth rate if α approx-gt 1

Characteristics of the TPE reversed-field pinch plasmas in conventional and improved confinement regimes

International Nuclear Information System (INIS)

Sakakita, H.; Asai, T.; Fiksel, G.; Yagi, Y.; Frassinetti, L.; Hayase, K.; Hirano, Y.; Kiyama, S.; Koguchi, H.; Shimada, T.; Innocente, P.; Spizzo, G.; Terranova, D.; Sato, Y.; Yoshikawa, M.

2005-01-01

We present the characteristics and experimental scaling laws of reversed-field pinch (RFP) plasmas, which are obtained from the recently established toroidal pinch experiment (TPE) database. The database contains information for approximately 1500 discharges consistently selected from four TPE RFP devices, and covers two decades of RFP experiments under conventional operating conditions at the National Institute of Advanced Industrial Science and Technology. We present the physics of the pulsed poloidal current drive (PPCD) discharges in the TPE-RX RFP device, and a comparison of the improved energy confinement time in PPCD, τ E P PCD , with τ E s caling as the reference scaling law (τ E s caling ∼ a 1.63 (I P 0.78 (I P /N) 0.33 Θ 2.97 ) in the TPE database, is attempted. The result shows that τ E P PCD agrees well with τ E s caling because of the strong pinch parameter dependence on the TPE scaling law. A potential improved confinement mode in the quasi-single-helicity (QSH) state is also investigated in TPE-RX, with respect to the operation conditions under which the QSH spontaneously appears in the core region, where a typical island structure is observed by means of soft Xray tomography. (author)

An Empirical Planetesimal Belt Radius–Stellar Luminosity Relation

Science.gov (United States)

Matrà, L.; Marino, S.; Kennedy, G. M.; Wyatt, M. C.; Öberg, K. I.; Wilner, D. J.

2018-05-01

Resolved observations of millimeter-sized dust, tracing larger planetesimals, have pinpointed the location of 26 Edgeworth–Kuiper Belt analogs. We report that a belt’s distance R to its host star correlates with the star’s luminosity L ⋆, following R\\propto {L}\\star 0.19 with a low intrinsic scatter of ∼17%. Remarkably, our Edgeworth–Kuiper Belt in the solar system and the two CO snow lines imaged in protoplanetary disks lie close to this R–L ⋆ relation, suggestive of an intrinsic relationship between protoplanetary disk structures and belt locations. To test the effect of bias on the relation, we use a Monte Carlo approach and simulate uncorrelated model populations of belts. We find that observational bias could produce the slope and intercept of the R–L ⋆ relation but is unable to reproduce its low scatter. We then repeat the simulation taking into account the collisional evolution of belts, following the steady-state model that fits the belt population as observed through infrared excesses. This significantly improves the fit by lowering the scatter of the simulated R–L ⋆ relation; however, this scatter remains only marginally consistent with the one observed. The inability of observational bias and collisional evolution alone to reproduce the tight relationship between belt radius and stellar luminosity could indicate that planetesimal belts form at preferential locations within protoplanetary disks. The similar trend for CO snow line locations would then indicate that the formation of planetesimals or planets in the outer regions of planetary systems is linked to the volatility of their building blocks, as postulated by planet formation models.

Waste Management Pinch Analysis (WAMPA): Application of Pinch Analysis for greenhouse gas (GHG) emission reduction in municipal solid waste management

International Nuclear Information System (INIS)

Ho, Wai Shin; Hashim, Haslenda; Lim, Jeng Shiun; Lee, Chew Tin; Sam, Kah Chiin; Tan, Sie Ting

2017-01-01

Highlights: • A novel method known as Waste Management Pinch Analysis (WAMPA) is presented. • WAMPA aims to identify waste management strategies based on specific target. • WAMPA is capable to examine the capacity of waste management strategies through graphical representation. - Abstract: Improper waste management happened in most of the developing country where inadequate disposal of waste in landfill is commonly practiced. Apart from disposal, MSW can turn into valuable product through recycling, energy recovery, and biological recovery action as suggested in the hierarchy of waste management. This study presents a method known as Waste Management Pinch Analysis (WAMPA) to examine the implication of a dual-objective – landfill and GHG emission reduction target in sustainable waste management. WAMPA is capable to identify the capacity of each waste processing strategy through graphical representation. A general methodology of WAMPA is presented through a demonstration of a SWM case followed by a detailed representation of WAMPA for five waste types. Application of the WAMPA is then applied on a case study for sustainable waste management planning from year 2015 to 2035. Three waste management strategies are incorporated into the case study – landfill, Waste-to-Energy (WtE), and reduce, reuse, and recycle (3R). The results show a 13.5% of total GHG emission reduction and 54.6% of total reduction of landfill are achieved. The major contributor of GHG emission which are from food waste (landfill emission) and plastic (WtE emission) is reduced.

On-conveyor belt determination of ash in coal

International Nuclear Information System (INIS)

Sowerby, B.; Lim, C.S.; Abernethy, D.A.; Liu, Y.; Maguire, P.A.

1997-01-01

A laboratory feasibility study has been carried out on new and advanced neutron and gamma-ray analysis systems for the direct on-conveyor belt analysis of ash in coal without the need for sample by-lines. Such an analysis system could deliver the combined advantages of a direct on-conveyor configuration with new and accurate analysis techniques. An industry survey of 18 coal companies carried out in early 1996 indicated that accurate on-belt ash analysis is of the highest priority. Subsequent laboratory work has focussed on the investigation of methods with the potential for improving the accuracy of ash content measurement relative to existing on-belt ash analysers, the most widely-used of which are based on dual energy gamma-ray transmission (DUET), which is sensitive to variations in ash composition. The current work indicates that on-belt neutron/gamma-ray techniques combined with advanced spectral analysis techniques show promise for development into an on-belt ash analysis system which is significantly less sensitive to composition changes than DUET and which analyses a much larger proportion of coal on the belt, thus eliminating some key sources of analysis error

Numerical simulations of annular wire-array z-pinches in (x,y), (r,θ), and (r,z) geometries

International Nuclear Information System (INIS)

Marder, B.M.; Sanford, T.W.L.; Allshouse, G.O.

1997-12-01

The Total Immersion PIC (TIP) code has been used in several two-dimensional geometries to understand better the measured dynamics of annular, aluminum wire-array z-pinches. The areas investigated include the formation of the plasma sheath from current-induced individual wire explosions, the effects of wire number and symmetry on the implosion dynamics, and the dependence of the Rayleigh-Taylor instability growth on initial sheath thickness. A qualitative change in the dynamics with increasing wire number was observed, corresponding to a transition between a z-pinch composed of non-merging, self-pinching individual wires, and one characterized by the rapid formation and subsequent implosion of a continuous plasma sheath. A sharp increase in radiated power with increasing wire number has been observed experimentally near this calculated transition. Although two-dimensional codes have correctly simulated observed power pulse durations, there are indications that three dimensional effects are important in understanding the actual mechanism by which these pulse lengths are produced

Compact reversed-field pinch reactors (CRFPR)

International Nuclear Information System (INIS)

Krakowski, R.A.; Miller, R.L.; Bathke, C.G.; Hagenson, R.L.; Copenhaver, C.; Werley, K.A.

1986-01-01

The unique confinement properties of the Reversed-Field Pinch (RFP) are exploited to examine physics and technical issues related to a compact, high-power-density fusion reactor. This resistive-coil, steady-state, toroidal device would use a dual-media power cycle driven by a fusion power core (FPC, i.e., plasma chamber, first wall, blanket, shield, and coils) with a power density and mass approaching values characteristic of pressurized-water fission rectors. A 1000-MWe(net) base case is selected from a comprehensive trade-off study to examine technological issues related to operating a high-power-density FPC. After describing the main physics and technology issues for this base-case reactor, directions for future study are suggested

36 CFR 1004.15 - Safety belts.

Science.gov (United States)

2010-07-01

... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Safety belts. 1004.15 Section 1004.15 Parks, Forests, and Public Property PRESIDIO TRUST VEHICLES AND TRAFFIC SAFETY § 1004.15 Safety... administered by the Presidio Trust will have the safety belt or child restraint system properly fastened at all...

Field reversed theta pinch TC-I UNICAMP

International Nuclear Information System (INIS)

Honda, R.Y.; Machida, M.; Aramaki, E.A.; Porto, P.; Berni, L.A.

1990-01-01

Field reversed configuration TC-I device is 16 cm diameter, 1 meter long with two mirror coils and 30 kJ field reversed theta pinch working for over two years at University of Campinas. Its implosion dynamics and field reversal parameters have been studied using flux excluded loops, internal magnetic probe, visible spectroscopy, photodiode array and image converter camera. The vacuum vessel is a pyrex tube of 14,5 cm diameter pumped with a liquid nitrogen cooled diffusion pump to a base pressure of 6 x 10 -7 Torr. The schematic view of the machine and experimental set up are shown. (Author)

Modulation of thermal conductivity in kinked silicon nanowires: phonon interchanging and pinching effects.

Science.gov (United States)

Jiang, Jin-Wu; Yang, Nuo; Wang, Bing-Shen; Rabczuk, Timon

2013-04-10

We perform molecular dynamics simulations to investigate the reduction of the thermal conductivity by kinks in silicon nanowires. The reduction percentage can be as high as 70% at room temperature. The temperature dependence of the reduction is also calculated. By calculating phonon polarization vectors, two mechanisms are found to be responsible for the reduced thermal conductivity: (1) the interchanging effect between the longitudinal and transverse phonon modes and (2) the pinching effect, that is, a new type of localization, for the twisting and transverse phonon modes in the kinked silicon nanowires. Our work demonstrates that the phonon interchanging and pinching effects, induced by kinking, are brand-new and effective ways in modulating heat transfer in nanowires, which enables the kinked silicon nanowires to be a promising candidate for thermoelectric materials.

Overview of the TITAN-II reversed-field pinch aqueous fusion power core design

Energy Technology Data Exchange (ETDEWEB)

Wong, C.P.C.; Creedon, R.L.; Grotz, S.; Cheng, E.T.; Sharafat, S.; Cooke, P.I.H.

1988-03-01

TITAN-II is a compact, high power density Reversed-Field Pinch fusion power reactor design based on the aqueous lithium solution fusion power core concept. The selected breeding and structural materials are LiNO/sub 3/ and 9-C low activation ferritic steel, respectively. TITAN-II is a viable alternative to the TITAN-I lithium self-cooled design for the Reversed-Field Pinch reactor to operate at a neutron wall loading of 18 MWm/sup 2/. Submerging the complete fusion power core and the primary loop in a large pool of cool water will minimize the probability of radioactivity release. Since the protection of the large pool integrity is the only requirement for the protection of the public, TITAN-II is a passive safety assurance design. 13 refs., 3 figs., 1 tab.

Overview of the TITAN-II reversed-field pinch aqueous fusion power core design

Energy Technology Data Exchange (ETDEWEB)

Wong, C.P.C.; Creedon, R.L.; Cheng, E.T. (General Atomic Co., San Diego, CA (USA)); Grotz, S.P.; Sharafat, S.; Cooke, P.I.H. (California Univ., Los Angeles (USA). Dept. of Mechanical, Aerospace and Nuclear Engineering; California Univ., Los Angeles, CA (USA). Inst. for Plasma and Fusion Research); TITAN Research Group

1989-04-01

TITAN-II is a compact, high-power-density Reversed-Field Pinch fusion power reactor design based on the aqueous lithium solution fusion power core concept. The selected breeding and structural materials are LiNO/sub 3/ and 9-C low activation ferritic steel, respectively. TITAN-II is a viable alternative to the TITAN-I lithium self-cooled design for the Reversed-Field Pinch reactor to operate at a neutron wall loading of 18 MW/m/sup 2/. Submerging the complete fusion power core and the primary loop in a large pool of cool water will minimize the probability of radioactivity release. Since the protection of the large pool integrity is the only requirement for the protection of the public, TITAN-II is a level 2 of passive safety assurance design. (orig.).

Growth of Rayleigh-Taylor and bulk convective instabilities in dynamics of plasma liners and pinches

International Nuclear Information System (INIS)

Bud'ko, A.B.; Velikovich, A.L.; Liberman, M.A.; Felber, F.S.

1989-01-01

Perturbation growth is studied for the initial, linear stage of an instability development in the course of a cylindrically-symmetric compression and expansion of plasma liners and Z-pinches with a sharp boundary. The hydrodynamic instabilities are Rayleigh-Taylor and bulk convective ones, the former being the most dengerous. Classification of the instability modes developing in accelerated plasmas, inclusing the local and global Rayleigh-Taylor modes, is given. The spectra of the instability growth rates are calculated for plasma liners and Z-pinches. The properties of the spectra appear to explain the filamentation and stratification of plasmas observed in the experiments with liners and Z-pinches. An axial magnetic field is shown to create a window of stability in the space of the flow parameters, where th Rayleigh-Taylor modes are fully suppressed by the magnetic shear, and the bulk convective ones - to a considerable extent. The axial magnetic field required to stabilize the implosion of a liner is estimated as B z0 =(10-30 kG)I(MA)/R 0 (cm), where I is the average current, R 0 - the initial radius of the liner

Development of Rayleigh-Taylor and bulk convection instabilities in the dynamics of plasma liners and pinches

International Nuclear Information System (INIS)

Bud'ko, A.B.; Velikovich, A.L.; Liberman, M.A.; Felber, F.S.

1989-01-01

A solution is derived for the problem of the initial, linear stage of the growth of small perturbations in the course of the cylindrically symmetric compression and expansion of a plasma liner and a Z-pinch with a sharp boundary. In these systems, Rayleigh-Taylor instabilities localized near the plasma boundaries are the most dangerous. Bulk convective instabilities develop in addition to these Rayleigh-Taylor instabilities. The various instability modes, including local and global Rayleigh-Taylor modes, which grown in an accelerated plasma with distributed profiles of hydrodynamic variables, are classified. The spectra of the instability growth rates are calculated for plasma liners and Z-pinches. The shape of these spectra reveals an explanation of the stratification and filamentation of the plasma observed experimentally in pinches and liners. The imposition of a longitudinal magnetic field gives rise to a stability window in the space of the flow parameters. In this window, the Rayleigh-Taylor modes are suppressed completely by magnetic shear, while the bulk convective modes are suppressed to a significant extent

Space-based pseudo-fixed latitude observation mode based on the characteristics of geosynchronous orbit belt

Science.gov (United States)

Hu, Yun-peng; Chen, Lei; Huang, Jian-yu

2017-08-01

The US Lincoln Laboratory proved that space-based visible (SBV) observation is efficient to observe space objects, especially Geosynchronous Orbit (GEO) objects. After that, SBV observation plays an important role in the space surveillance. In this paper, a novel space-based observation mode is designed to observe all the GEO objects in a relatively short time. A low earth orbit (LEO) satellite, especially a dawn-dusk sun-synchronous orbit satellite, is useful for space-based observation. Thus, the observation mode for GEO objects is based on a dawn-dusk sun-synchronous orbit satellite. It is found that the Pinch Point (PP) regions proposed by the US Lincoln Laboratory are spreading based on the analysis of the evolution principles of GEO objects. As the PP regions becoming more and more widely in the future, many strategies based on it may not be efficient any more. Hence, the key point of the space-based observation strategy design for GEO objects should be emphasized on the whole GEO belt as far as possible. The pseudo-fixed latitude observation mode is proposed in this paper based on the characteristics of GEO belt. Unlike classical space-based observation modes, pseudo-fixed latitude observation mode makes use of the one-dimensional attitude adjustment of the observation satellite. The pseudo-fixed latitude observation mode is more reliable and simple in engineering, compared with the gazing observation mode which needs to adjust the attitude from the two dimensions. It includes two types of attitude adjustment, i.e. daily and continuous attitude adjustment. Therefore, the pseudo-fixed latitude observation mode has two characteristics. In a day, the latitude of the observation region is fixed and the scanning region is about a rectangle, while the latitude of the observation region centre changes each day in a long term based on a daily strategy. The capabilities of a pseudo-fixed latitude observation instrument with a 98° dawn-dusk sun-synchronous orbit are

Estimates Of Radiation Belt Remediation Requirements

Science.gov (United States)

Tuszewski, M.; Hoyt, R. P.; Minor, B. M.

2004-12-01

A low-Earth orbit nuclear detonation could produce an intense artificial radiation belt of relativistic electrons. Many satellites would be destroyed within a few weeks. We present here simple estimates of radiation belt remediation by several different techniques, including electron absorption by gas release, pitch angle scattering by steady electric and magnetic fields from tether arrays, and pitch angle scattering by wave-particle interactions from in-situ transmitters. For each technique, the mass, size, and power requirements are estimated for a one-week remediation (e-folding) timescale, assuming that a 10 kTon blast trapped 1024 fission product electrons (1 to 8 MeV) at L = 1.5 in a dipolar belt of width dL = 0.1.

The fabrication techniques of Z-pinch targets. Techniques of fabricating self-adapted Z-pinch wire-arrays

International Nuclear Information System (INIS)

Qiu Longhui; Wei Yun; Liu Debin; Sun Zuoke; Yuan Yuping

2002-01-01

In order to fabricate wire arrays for use in the Z-pinch physical experiments, the fabrication techniques are investigated as follow: Thickness of about 1-1.5 μm of gold is electroplated on the surface of ultra-fine tungsten wires. Fibers of deuterated-polystyrene (DPS) with diameters from 30 to 100 microns are made from molten DPS. And two kinds of planar wire-arrays and four types of annular wire-arrays are designed, which are able to adapt to the variation of the distance between the cathode and anode inside the target chamber. Furthermore, wire-arrays with diameters form 5-24 μm are fabricated with tungsten wires, respectively. The on-site test shows that the wire-arrays can self-adapt to the distance changes perfectly

Note: On the generation of sub-300 keV flash-X-rays using rod-pinch diode: An experimental investigation

Energy Technology Data Exchange (ETDEWEB)

Satyanarayana, N.; Rajawat, R. K.; Basu, Shibaji [Facility for Electromagnetic Systems, BARCF(V), B-Block, Autonagar, Visakhapatnam 530012, Andhra Pradesh (India); Rao, A. Durga Prasad [Department of Nuclear Physics, Andhra University, Visakhapatnam 530001, Andhra Pradesh (India); Mittal, K. C. [Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, Maharashtra (India)

2014-09-15

Generation of flash X-rays (FXRs) at less than 500 keV is described with emphasis on experimental investigation. The pulser is a Tesla transformer-Water transmission line based pulsed power generator operating in double resonance mode to power a rod-pinch diode. The configuration of aspect ratio reported here falls much below the normally reported ratios for the rod-pinch diode operation. Experimental investigation at such low pulsed voltage has revealed “flowering” of the anode tip and “pitting” of the perspex window. A possible explanation in terms of Lorentz body force is discussed rather than the pinch mechanism generally suggested in literature. The experimental investigation for the FXR generation is corroborated by measuring the radiation dose using CaSO{sub 4} (Dy) thermo luminescent dosimeters.

Plasma resistivity in a slow rising current theta-pinch device

International Nuclear Information System (INIS)

Kayama, Milton Eiji; Dobrowolsky, Marcelo Shubert; Honda, Roberto Yzumi; Aramaki, Emilia Akemi; Algatti, Mauricio Antonio

1998-01-01

Anomalous behavior of plasma resistivity was observed in a Theta-pinch plasma. A comparative analysis was performed with a hybrid numerical code where the Chodura s resistivity algorithm is included. Good agreement was found in the radial plasma dynamic description. The experimental value of resistivity at null field point was found to be one order of magnitude greater than the theoretical prediction. (author)

The effects of preionization level on a 'stabilized' z-pinch

International Nuclear Information System (INIS)

Silawatshananai, C.; Anderson, F.S.B.; Brennan, M.H.; Durance, G.; Jones, I.R.; Murray, E.L.; Tendys, J.

1980-02-01

The influence of the degree of preionization on the formation and properties of a conventional 'stabilized' Z-pinch has been studied experimentally for preionization levels ranging from 2% to 35%. It is concluded that there exists the possibility of using varying levels of preionization to tailor radial profiles of density and pressure, and hence to influence the value of βsub(theta)

Modeling of Jupiter's electron an ion radiation belts

International Nuclear Information System (INIS)

Sicard, Angelica

2004-01-01

In the Fifties, James Van Allen showed the existence of regions of the terrestrial magnetosphere consisted of energetic particles, trapped by the magnetic field: the radiation belts. The radiation belts of the Earth were the subject of many modeling works and are studied since several years at the Departement Environnement Spatial (DESP) of ONERA. In 1998, the DESP decided to adapt the radiation belts model of the Earth, Salammbo, to radiation environment of Jupiter. A first thesis was thus carried out on the subject and a first radiation belts model of electrons of Jupiter was developed [Santos-Costa, 2001]. The aim of this second thesis is to develop a radiation belts model for protons and heavy ions. In order to validate the developed model, the comparisons between Salammbo results and observations are essential. However, the validation is difficult in the case of protons and heavy ions because in-situ measurements of the probes are very few and most of the time contaminated by very energetic electrons. To solve this problem, a very good model of electrons radiation belts is essential to confirm or cancel the contamination of protons and heavy ions measurements. Thus, in parallel to the development of the protons and heavy ions radiation belts model, the electrons models, already existing, has been improved. Then Salammbo results have been compared to the different observations available (in-situ measurements, radio-astronomical observations). The different comparisons show a very good agreement between Salammbo results and observations. (author) [fr

Mesin Pemindah Bahan : Studi Prestasi Belt Conveyor Hubungannya Dengan Ukuran Butiran Dan Tingkat Kelembaban Bahan Curah ( Batubara ), Panjang Belt 7,6 Meter ; Lebar 32 Centimeter

OpenAIRE

Nugroho, Rio

2011-01-01

Banyak industri yang menggunakan belt conveyor sebagai alat transportasi material, sebab punya banyak keuntungan. Sehingga, untuk meningkatkan performansi belt conveyor tersebut perlu dilakukan pengidentifikasian prestasi belt conveyor. Identifikasi dilakukan dengan material transfer batubara. Yang akan diamati adalah pengaruh ukuran butiran material dan tingkat kelembaban terhadap kapasitas transfer belt conveyor. Dari pengujian didapatkan kapasitas transfer terbesar adalah material batubar...

Field simulation of axisymmetric plasma screw pinches by alternating-direction-implicit methods

International Nuclear Information System (INIS)

Lambert, M.A.

1996-06-01

An axisymmetric plasma screw pinch is an axisymmetric column of ionized gaseous plasma radially confined by forces from axial and azimuthal currents driven in the plasma and its surroundings. This dissertation is a contribution to detailed, high resolution computer simulation of dynamic plasma screw pinches in 2-d rz-coordinates. The simulation algorithm combines electron fluid and particle-in-cell (PIC) ion models to represent the plasma in a hybrid fashion. The plasma is assumed to be quasineutral; along with the Darwin approximation to the Maxwell equations, this implies application of Ampere's law without displacement current. Electron inertia is assumed negligible so that advective terms in the electron momentum equation are ignored. Electrons and ions have separate scalar temperatures, and a scalar plasma electrical resistivity is assumed. Altemating-direction-implicit (ADI) methods are used to advance the electron fluid drift velocity and the magnetic fields in the simulation. The ADI methods allow time steps larger than allowed by explicit methods. Spatial regions where vacuum field equations have validity are determined by a cutoff density that invokes the quasineutral vacuum Maxwell equations (Darwin approximation). In this dissertation, the algorithm was first checked against ideal MM stability theory, and agreement was nicely demonstrated. However, such agreement is not a new contribution to the research field. Contributions to the research field include new treatments of the fields in vacuum regions of the pinch simulation. The new treatments predict a level of magnetohydrodynamic turbulence near the bulk plasma surface that is higher than predicted by other methods

Survey of current situation in radiation belt modeling

Science.gov (United States)

Fung, Shing F.

2004-01-01

The study of Earth's radiation belts is one of the oldest subjects in space physics. Despite the tremendous progress made in the last four decades, we still lack a complete understanding of the radiation belts in terms of their configurations, dynamics, and detailed physical accounts of their sources and sinks. The static nature of early empirical trapped radiation models, for examples, the NASA AP-8 and AE-8 models, renders those models inappropriate for predicting short-term radiation belt behaviors associated with geomagnetic storms and substorms. Due to incomplete data coverage, these models are also inaccurate at low altitudes (e.g., <1000 km) where many robotic and human space flights occur. The availability of radiation data from modern space missions and advancement in physical modeling and data management techniques have now allowed the development of new empirical and physical radiation belt models. In this paper, we will review the status of modern radiation belt modeling. Published by Elsevier Ltd on behalf of COSPAR.

Wearing an abdominal belt increases diastolic blood pressure.

Science.gov (United States)

Rafacz, W; McGill, S M

1996-09-01

The purpose of this study was to determine the effect of wearing an abdominal belt on blood pressure (systolic and diastolic) and heart rate during a variety of tasks. The belt was typical of the elastic type with suspenders and Velcro tabs for cinching the belt snug. The tasks performed included sitting at rest, sitting with the torso inclined forward at 45 degrees, standing with the torso inclined forward at 45 degrees (with and without holding an 11-kg weight), a trunk axial rotation task, and squat lifting. Blood pressure was monitored noninvasively with a FINAPRES blood pressure monitor. Twenty healthy men performed each task with and without the abdominal belt. Although no significant increases in mean systolic blood pressure or heart rate were found, there was a significant increase in diastolic blood pressure in all conditions. All people considering wearing an abdominal belt should also consider the risks and liability associated with the additional cardiovascular load, particularly heart attack and stroke.

ANTHEM simulation of the early time magnetic field penetration of the plasma surrounding a high density Z-pinch

International Nuclear Information System (INIS)

Mason, R.J.

1989-01-01

The early time penetration of magnetic field into the low density coronal plasma of a Z-pinch fiber is studied with the implicit plasma simulation code ANTHEM. Calculations show the emission of electrons from the cathode, pinching of the electron flow, magnetic insulation of the electrons near the anode, and low density ion blow off. PIC-particle ion calculations show a late time clumping of the ion density not seen with a fluid ion treatment. 4 refs., 4 figs

Study on a metal pushing V-belt type CVT. Numerical analysis for belt tension distribution in brands of a ring at steady state; Kinzoku V belt wo mochiita CVT ni kansuru kenkyu. Sekiso belt (steel ring) no dendo kiko kaiseki

Energy Technology Data Exchange (ETDEWEB)

Fujii, T; Kuwabara, S [Doshisha University, Kyoto (Japan); Kanehara, S [Honda Motor Co. Ltd., Tokyo (Japan)

1997-10-01

The power transmitting mechanisms for laminated belts were studied to analyze belt tension in each band of the ring of metal V-belts. A numerical model consisting of linear springs and frictional elements was proposed. The present model was experimentally proved. It is revealed based on the numerical results that each band shares the ring tension equally when the coefficients of friction for bands and a pulley are the same while the first band must support more when the coefficients of friction between two bands are lower than that between a saddle surface of the block and the inner band. 4 refs., 9 figs.

An Effective Belt Conveyor for Underground Ore Transportation Systems

Science.gov (United States)

Krol, Robert; Kawalec, Witold; Gladysiewicz, Lech

2017-12-01

Raw material transportation generates a substantial share of costs in the mining industry. Mining companies are therefore determined to improve the effectiveness of their transportation system, focusing on solutions that increase both its energy efficiency and reliability while keeping maintenance costs low. In the underground copper ore operations in Poland’s KGHM mines vast and complex belt conveyor systems have been used for horizontal haulage of the run-of-mine ore from mining departments to shafts. Basing upon a long-time experience in the field of analysing, testing, designing and computing of belt conveyor equipment with regard to specific operational conditions, the improvements to the standard design of an underground belt conveyor for ore transportation have been proposed. As the key elements of a belt conveyor, the energy-efficient conveyor belt and optimised carrying idlers have been developed for the new generation of underground conveyors. The proposed solutions were tested individually on the specially constructed test stands in the laboratory and in the experimental belt conveyor that was built up with the use of prototype parts and commissioned for the regular ore haulage in a mining department in the KGHM underground mine “Lubin”. Its work was monitored and the recorded operational parameters (loadings, stresses and strains, energy dissipation, belt tracking) were compared with those previously collected on a reference (standard) conveyor. These in-situ measurements have proved that the proposed solutions will return with significant energy savings and lower maintenance costs. Calculations made on the basis of measurement results in the specialized belt conveyor designing software allow to estimate the possible savings if the modernized conveyors supersede the standard ones in a large belt conveying system.

Response to 'Comment on 'Pinch current limitation effect in plasma focus'' [Appl. Phys. Lett. 94, 076101 (2009)

International Nuclear Information System (INIS)

Lee, S.; Saw, S. H.

2009-01-01

The main point of the comment [Appl. Phys. Lett. 94, 076101 (2009)] is that Eq. (2) and consequentially Eq. (3) of the commented paper [Appl. Phys. Lett. 92, 021503 (2008)] require correction. The alternative equation suggested in the comment is derived using Kirchhoff's voltage rule. The comment consider only the energy distribution in the inductive components and the resultant equation confirms a progressive lowering of the I pinch /I peak ratio as the static inductance L 0 is reduced, lowering from 0.87 to 0.31 as L 0 is reduced from 100 to 5 nH according to the revised formula corresponding to Eq. (3), compared to 0.63-0.25 according to Eq. (3). This progressive lowering of the ratio I pinch /I peak due to the inductive energy distribution is one of two factors responsible for the pinch current limitation. The other factor is the progressive reduction in the L-C interaction time compared to the current dip duration denoted by δ cap in Eq. (2). The comment does not deal with δ cap at all; hence, its conclusion based on inductive energy distribution only is not useful, since in the low L 0 region when pinch current limitation begins to manifest, δ cap becomes more and more the dominant factor. In any case, the results of the paper do not depend on Eqs. (2) and (3), which are used in the paper only for illustrative purposes

Primary experimental results of wire-array Z-pinches on PTS

Energy Technology Data Exchange (ETDEWEB)

Huang, X. B., E-mail: caephxb2003@aliyun.com; Zhou, S. T., E-mail: caephxb2003@aliyun.com; Ren, X. D., E-mail: caephxb2003@aliyun.com; Dan, J. K., E-mail: caephxb2003@aliyun.com; Wang, K. L., E-mail: caephxb2003@aliyun.com; Zhang, S. Q., E-mail: caephxb2003@aliyun.com; Li, J., E-mail: caephxb2003@aliyun.com; Xu, Q., E-mail: caephxb2003@aliyun.com; Cai, H. C., E-mail: caephxb2003@aliyun.com; Duan, S. C., E-mail: caephxb2003@aliyun.com; Ouyang, K., E-mail: caephxb2003@aliyun.com; Chen, G. H., E-mail: caephxb2003@aliyun.com; Ji, C., E-mail: caephxb2003@aliyun.com; Wang, M., E-mail: caephxb2003@aliyun.com; Feng, S. P., E-mail: caephxb2003@aliyun.com; Yang, L. B., E-mail: caephxb2003@aliyun.com; Xie, W. P., E-mail: caephxb2003@aliyun.com; Deng, J. J., E-mail: caephxb2003@aliyun.com [Key Lab of Pulsed Power, Institute of Fluid Physics, CAEP, P.O. Box 919-108, Mianyang, Sichuan 621999 (China)

2014-12-15

The Primary Test Stand (PTS) developed at the China Academy of Engineering Physics is a multiterawatt pulsed power driver, which can deliver a ∼10 MA, 70 ns rise-time (10%-90%) current to a short circuit load and has important applications in Z-pinch driven inertial confinement fusion and high energy density physics. In this paper, primary results of tungsten wire-array Z-pinch experiments on PTS are presented. The load geometries investigated include 15-mm-tall cylindrical single and nested arrays with diameter ranging from 14.4-26.4 mm, and consisting of 132∼276 tungsten wires with 5∼10 μm in diameter. Multiple diagnostics were fielded to determine the characteristics of x-ray radiations and to obtain self-emitting images of imploding plasmas. X-ray power up to 80 TW with ∼3 ns FWMH is achieved by using nested wire arrays. The total x-ray energy exceeds 500 kJ and the peak radiation temperature is about 150 eV. Typical velocity of imploding plasmas goes around 3∼5×10{sup 7} cm/s and the radial convergence ratio is between 10 and 20.

Modeling and energy efficiency optimization of belt conveyors

International Nuclear Information System (INIS)

Zhang, Shirong; Xia, Xiaohua

2011-01-01

Highlights: → We take optimization approach to improve operation efficiency of belt conveyors. → An analytical energy model, originating from ISO 5048, is proposed. → Then an off-line and an on-line parameter estimation schemes are investigated. → In a case study, six optimization problems are formulated with solutions in simulation. - Abstract: The improvement of the energy efficiency of belt conveyor systems can be achieved at equipment and operation levels. Specifically, variable speed control, an equipment level intervention, is recommended to improve operation efficiency of belt conveyors. However, the current implementations mostly focus on lower level control loops without operational considerations at the system level. This paper intends to take a model based optimization approach to improve the efficiency of belt conveyors at the operational level. An analytical energy model, originating from ISO 5048, is firstly proposed, which lumps all the parameters into four coefficients. Subsequently, both an off-line and an on-line parameter estimation schemes are applied to identify the new energy model, respectively. Simulation results are presented for the estimates of the four coefficients. Finally, optimization is done to achieve the best operation efficiency of belt conveyors under various constraints. Six optimization problems of a typical belt conveyor system are formulated, respectively, with solutions in simulation for a case study.

"Abomination"--life as a Bible belt gay.

Science.gov (United States)

Barton, Bernadette

2010-01-01

Drawing on observation, autoethnography, and audio-taped interviews, this article explores the religious backgrounds and experiences of Bible Belt gays. In the Bible Belt, Christianity is not confined to Sunday worship. Christian crosses, messages, paraphernalia, music, news, and attitudes permeate everyday settings. Consequently, Christian fundamentalist dogma about homosexuality-that homosexuals are bad, diseased, perverse, sinful, other, and inferior-is cumulatively bolstered within a variety of other social institutions and environments in the Bible Belt. Of the 46 lesbians and gay men interviewed for this study (age 18-74 years), most describe living through spirit-crushing experiences of isolation, abuse, and self-loathing. This article argues that the geographic region of the Bible Belt intersects with religious-based homophobia. Informants explained that negative social attitudes about homosexuality caused a range of harmful consequences in their lives including the fear of going to hell, depression, low self-esteem, and feelings of worthlessness.

Process integration and pinch analysis in sugarcane industry

Energy Technology Data Exchange (ETDEWEB)

Prado, Adelk de Carvalho; Pinheiro, Ricardo Brant [UFMG, Departamento de Engenharia Nuclear, Programa de Pos-Graduacao em Ciencias e Tecnicas Nucleares, Belo Horizonte, MG (Brazil)], E-mail: rbp@nuclear.ufmg.br

2010-07-01

Process integration techniques were applied, particularly through the Pinch Analysis method, to sugarcane industry. Research was performed upon harvest data from an agroindustrial complex which processes sugarcane plant in excess of 3.5 million metric tons per year, producing motor fuel grade ethanol, standard quality sugar, and delivering excess electric power to the grid. Pinch Analysis was used in assessing internal heat recovery as well as external utility demand targets, while keeping the lowest but economically achievable targets for entropy increase. Efficiency on the use of energy was evaluated for the plant as it was found (the base case) as well as for five selected process and/or plant design modifications, always with guidance of the method. The first alternative design (case 2) was proposed to evaluate equipment mean idle time in the base case, to support subsequent comparisons. Cases 3 and 4 were used to estimate the upper limits of combined heat and power generation while raw material supply of the base case is kept; both the cases did not prove worth implementing. Cases 5 and 6 were devised to deal with the bottleneck of the plant, namely boiler capacity, in order to allow for some production increment. Inexpensive, minor modifications considered in case 5 were found unable to produce reasonable outcome gain. Nevertheless, proper changes in cane juice evaporation section (case 6) could allow sugar and ethanol combined production to rise up to 9.1% relative to the base case, without dropping cogenerated power. (author)

A heuristic model for the nonlinear Rayleigh--Taylor instability in fast Z pinches

International Nuclear Information System (INIS)

Hussey, T.W.; Roderick, N.F.; Shumlak, U.; Spielman, R.B.; Deeney, C.

1995-01-01

A simple, heuristic model for the early nonlinear phase of the Rayleigh--Taylor instability (RTI) in thin-cylindrical-shell Z-pinch implosions has been developed. This model is based on the fact that, as the field--plasma interface is deformed, there is a component of the applied force that acts to move mass from the low mass per unit area bubble region into the higher mass per unit area spike region. The resulting reduced mass per unit area of the bubble causes it to be preferentially accelerated ahead of the spike. The pinch begins to radiate as the bubble mass first reaches the axis, and it continues to radiate while the mass that is entrained within the spikes and within unperturbed parts of the shell also arrives on axis. This model relates the time at which the bubble arrives on axis to an initial wavelength and amplitude of a single mode of the RTI. Then, by comparing this to the time at which the unperturbed mass reaches the axis, one estimates pinch thermalization time, a quantity that is determined experimentally. Experimental data, together with analytic models, have been used to choose appropriate initial wavelength and amplitude both for foils and for certain gas puff implosions. By noting that thermalization time is a weak function of these parameters, it is argued that one may use the same values for an extrapolative study of qualitatively similar implosions

Gravity inferred subsurface structure of Gadwal Schist belt, Andhra

Indian Academy of Sciences (India)

Detailed gravity data collected across the Gadwal schist belt in the state of Andhra Pradesh show an 8.4 mgal residual gravity anomaly associated with meta-sediments/volcanics of the linear NNW-SSE trending schist belt that shows metamorphism from green schist to amphibolite facies. This schist belt is flanked on either ...

Soft X-Ray Spectra from High Current Nitrogen Z-Pinch Discharge

Czech Academy of Sciences Publication Activity Database

Vrba, Pavel; Vrbová, M.; Nevrkla, M.; Jančárek, A.

2016-01-01

Roč. 3, č. 1 (2016), s. 48 ISSN 2336-2626. [SPPT 2016 - 27th Symposium on Plasma Physics and Technology/27./. Prague, 20.06.2016-23.06.2016] Institutional support: RVO:61389021 Keywords : Capillary discharge * recombination pumping * pinch dynamics * evolution of spectra emission * computer modelling Subject RIV: BH - Optics, Masers, Lasers www.plasmaconference.cz

Using haptic feedback to increase seat belt use : traffic tech.

Science.gov (United States)

2011-07-01

The legacy of research on increasing seat belt use has : focused on enactment of seat belt legislation, public education, : high-visibility police enforcement, and seat belt : reminder systems. Several behavioral programs have : produced large, susta...

Seat belt injuries and sigmoid colon trauma.

OpenAIRE

Eltahir, E M; Hamilton, D

1997-01-01

Colonic seat belt injuries are rare but carry higher mortality rates than small bowel injuries. The case of a 44 year old man is described who had severe sigmoid colon compression injury from his seat belt a few days after a road traffic accident.

Shot-by-shot spectrum model for rod-pinch, pulsed radiography machines

Directory of Open Access Journals (Sweden)

Wm M. Wood

2018-02-01

Full Text Available A simplified model of bremsstrahlung production is developed for determining the x-ray spectrum output of a rod-pinch radiography machine, on a shot-by-shot basis, using the measured voltage, V(t, and current, I(t. The motivation for this model is the need for an agile means of providing shot-by-shot spectrum prediction, from a laptop or desktop computer, for quantitative radiographic analysis. Simplifying assumptions are discussed, and the model is applied to the Cygnus rod-pinch machine. Output is compared to wedge transmission data for a series of radiographs from shots with identical target objects. Resulting model enables variation of parameters in real time, thus allowing for rapid optimization of the model across many shots. “Goodness of fit” is compared with output from LSP Particle-In-Cell code, as well as the Monte Carlo Neutron Propagation with Xrays (“MCNPX” model codes, and is shown to provide an excellent predictive representation of the spectral output of the Cygnus machine. Improvements to the model, specifically for application to other geometries, are discussed.

A moving finite element model of the high density z-pinch

International Nuclear Information System (INIS)

Glasser, A.H.

1989-01-01

This paper presents the results of computations of the behavior of the fiber-initiated high density Z-pinch (HDZP). It purpose is twofold. One is to study the behavior of the physical system itself as an interesting controlled fusion experiment. The main result of this study is a demonstration of the relaxation of the full inertial behavior of the pinch to simplified self-similar behavior in which the forces on the system are in near balance. The moving free boundary and violent initial behavior of this configuration require carful treatment. This leads to the other purpose of the work, to use this realistic physical system as a test-bed for a general-purpose 1-dimensional code based on moving finite elements. A key step in accomplishing this goal has been the recognition that numerical stability of the discretized equations has required the use of nonconservative quantities as the fundamental dependent variables to be discretized. The main result of this work is a code which is capable of treating a very general class of nonlinear, time-dependent fluid equations. copyright 1989 Academic Press, Inc

Shot-by-shot spectrum model for rod-pinch, pulsed radiography machines

Science.gov (United States)

Wood, Wm M.

2018-02-01

A simplified model of bremsstrahlung production is developed for determining the x-ray spectrum output of a rod-pinch radiography machine, on a shot-by-shot basis, using the measured voltage, V(t), and current, I(t). The motivation for this model is the need for an agile means of providing shot-by-shot spectrum prediction, from a laptop or desktop computer, for quantitative radiographic analysis. Simplifying assumptions are discussed, and the model is applied to the Cygnus rod-pinch machine. Output is compared to wedge transmission data for a series of radiographs from shots with identical target objects. Resulting model enables variation of parameters in real time, thus allowing for rapid optimization of the model across many shots. "Goodness of fit" is compared with output from LSP Particle-In-Cell code, as well as the Monte Carlo Neutron Propagation with Xrays ("MCNPX") model codes, and is shown to provide an excellent predictive representation of the spectral output of the Cygnus machine. Improvements to the model, specifically for application to other geometries, are discussed.

Opacity measurements of tamped NaBr samples heated by z-pinch X-rays

International Nuclear Information System (INIS)

Bailey, J.E.; Arnault, P.; Blenski, T.; Dejonghe, G.; Peyrusse, O.; MacFarlane, J.J.; Mancini, R.C.; Cuneo, M.E.; Nielsen, D.S.; Rochau, G.A.

2003-01-01

Laboratory measurements provide benchmark data for wavelength-dependent plasma opacities to assist inertial confinement fusion, astrophysics, and atomic physics research. There are several potential benefits to using z-pinch radiation for opacity measurements, including relatively large cm-scale lateral sample sizes and relatively-long 3-5 ns experiment durations. These features enhance sample uniformity. The spectrally resolved transmission through a CH-tamped NaBr foil was measured. The z-pinch produced the X-rays for both the heating source and backlight source. The (50±4) eV foil electron temperature and (3±1)x10 21 cm -3 foil electron density were determined by analysis of the Na absorption features. LTE and NLTE opacity model calculations of the n=2 to 3, 4 transitions in bromine ionized into the M-shell are in reasonably good agreement with the data

Radiometric measurement independent of profile. Belt weighers

International Nuclear Information System (INIS)

Otto, J.

1986-01-01

Radiometric measuring techniques allow contactless determination of the material carried by belt conveyors. Data defining the material is obtained via attenuation of gamma rays passing through the material on the belt. The method applies the absorption law according to Lambert-Beer, which has to be corrected by a build-up factor because of the stray radiation induced by the Compton effect. The profile-dependent error observed with conventional radiometric belt weighers is caused by the non-linearity of the absorption law in connection with the simultaneous summation of the various partial rays in a detector. The scanning method allows separate evaluation of the partial rays' attenuation and thus yields the correct data of the material carried, regardless of the profile. The scanning method is applied on a finite number of scanning sections, and a residual error has to be taken into account. The stochastics of quantum emission and absorption leads to an error whose expectation value is to be taken into account in the scanning algorithm. As the conveyor belt is in motion during the process of measurements, only part of the material conveyed is irradiated. The resulting assessment error is investigated as a function of the autocorrelation function of the material on the belt. (orig./HP) [de

A comparison of muscle activation between back squats and belt squats.

Science.gov (United States)

Evans, Thomas W; McLester, Cherilyn N; Howard, Jonathan H; McLester, John R; Calloway, Jimmy P

2017-06-08

A machine belt squat is a piece of equipment designed to allow the performance of squats while loading weight on the lifter's hips using a belt. The purpose of this investigation was to determine if belt squats differ from back squats in activation of the primary movers, and to determine the predictive capabilities of back squat load, training status, and anthropometric data on belt squat load. Thirty-one participants (16 males and 15 females) completed anthropometric measurements, a demographic questionnaire, a familiarization visit, and two testing visits, completing a 5 repetition maximum test for back squat and belt squat. Surface electromyography was used to measure muscle activation for the left and right vastus medialis (VMO), vastus lateralis (VLO), rectus femoris (RF), and gluteus maximus (GM). Comparison of muscle activation between the two exercises showed significant differences in the left GM (back squat: 0.84 ± 0.45, belt squat: 0.69 ± 0.22, p=0.015) and right GM (back squat: 0.86 ± 0.45, belt squat: 0.71 ± 0.29, p=0.004). Regression analysis computed significant prediction equations for belt squat load for general population, males, females, and advanced lifters. Overall, results indicate that belt squats may significantly differ in GM activation from back squats. Back squat load, as well as other variables, may be effective in accurately estimating appropriate belt squat load. These findings may help to more appropriately program for training with machine belt squats as a back squat alternative.

The impact of plasma dynamics on the self-magnetic-pinch diode impedance

International Nuclear Information System (INIS)

Bennett, Nichelle; Crain, M. Dale; Droemer, Darryl W.; Gignac, Raymond E.; Molina, Isidro; Obregon, Robert; Smith, Chase C.; Wilkins, Frank L.; Welch, Dale R.; Webb, Timothy J.; Mazarakis, Michael G.; Kiefer, Mark L.; Johnston, Mark D.; Leckbee, Joshua J.; Nielsen, Dan; Romero, Tobias; Simpson, Sean; Ziska, Derek

2015-01-01

The self-magnetic-pinch diode is being developed as an intense electron beam source for pulsed-power-driven x-ray radiography. The basic operation of this diode has long been understood in the context of pinched diodes, including the dynamic effect that the diode impedance decreases during the pulse due to electrode plasma formation and expansion. Experiments being conducted at Sandia National Laboratories' RITS-6 accelerator are helping to characterize these plasmas using time-resolved and time-integrated camera systems in the x-ray and visible. These diagnostics are analyzed in conjunction with particle-in-cell simulations of anode plasma formation and evolution. The results confirm the long-standing theory of critical-current operation with the addition of a time-dependent anode-cathode gap length. The results may suggest that anomalous impedance collapse is driven by increased plasma radial drift, leading to larger-than-average ion v r × B θ acceleration into the gap

Study of flow and loss processes at the ends of a linear theta pinch. Progress report for the period June 1, 1976--May 31, 1977

International Nuclear Information System (INIS)

York, T.M.; Klevans, E.H.

1977-02-01

Experimental and analytical studies initiating and supporting research on flow and energy losses at the ends of a linear theta pinch have been carried out. A 25 cm linear pinch coil has been driven by a 515,000 A discharge with 10 μsec half-cycle time supplied by a 100 μF, 18 kV energy storage system. With reliable preionization generated up to 400 mT He, current sheath behavior has been identified with magnetic loop probes and double loop probes. Spectroscopic determination of preionization has been made. A ruby laser Thomson scattering diagnostic has been designed and is being procured. A study of transient plasma behavior in a 10 cm theta pinch has been carried out with a Twyman-Green interferometer using a 7 mW He--Ne CW laser. Pressure, electric field, and velocity probe diagnostics have received preliminary testing. Design work has been completed for the doubling of pinch length and energy storage system. Studies of particle loss scaling and reactor scaling of linear theta pinch devices have been reported. Detailed calculations of plasma properties at the end of the pinch coil following expansion from the central coil have been carried out. A O--D, time dependent computer code that includes conduction, convection, and magnetic field diffusion has been developed. Predicted plasma behavior is in good agreement with experimental data

New bifocal pinch experiment SPEED 3

International Nuclear Information System (INIS)

Raacke, J.; Berntien, U.; Decker, G.; Kies, W.; Roewekamp, P.

1996-01-01

The SPEED 3 compact plasma focus device will be used as a soft x-ray source for various practical applications. It exploits a bifocal configuration with a plane insulator, very short accelerator and a hollow inner electrode. The discharge is driven by eight parallel two-stage Marx modules, capable of delivering up to 1.25 MA of current with the rise time of 0.3 s. The key parts of the device, the plasma diagnostic systems used, and the processes in the discharge are described in the paper. Framing camera pictures of a typical discharge are shown for illustration. The results of preliminary experiments are discussed, dealing almost exclusively with the discharge inaction, sheath and pinch formation. (J.U.). 1 tab., 3 figs., 2 refs