Channel-accelerating gap interaction and beam acceleration and transport experiments with the recirculating linear accelerator (RLA)

International Nuclear Information System (INIS)

Mazarakis, M.G.; Smith, D.L.; Poukey, J.W.; Wagner, J.S.; Bennett, L.F.; Olson, W.R.; Turman, B.N.; Prestwich, K.R.; Wells, J.; Struve, K.

1992-01-01

The lifetime of the Ion Focusing Regime (IFR) channel following the pulsing of the post-accelerating gaps is critical for open-ended low energy devices. It dictates the number of allowable beam recirculations through the gaps. In the case of a closed racetrack configuration, it is significant but not as critical, since the presence of the electron beam focuses the ions and lengthens the lifetime of the ion channel. The authors have experimentally established that pulsing an accelerating gap perturbs the IFR channel. However for the parameters studied, the lifetime is long enough to allow at least four beam recirculations in a spiral device. In addition transparent grids of cusp fields positioned upstream and downstream from the gaps prevent them from perturbing the IFR channel. Experiments were performed with and without injected electron beams. For the experiments investigating the IFR channel interaction with the accelerating gap, the injector was removed and the beam line was extended downstream and upstream from the accelerating cavity. Only the first straight section of the RLA with one accelerating cavity (ET-2) was utilized. The acceleration and transport experiments were performed utilizing two injectors: first the low energy 1.3-MV Isolated Blumlein (IB) injector and most recently the new 4-MV 20-kA injector. Beams of 6--20 kA current were produced and successfully transported and accelerated through the ET-2 post-accelerating gap. For both injectors an apertured non-immersed ion-focused foilless diode was selected among various options. It is the simplest and easiest to operate and can be adjusted to provide variable beam impedance loads to the injector. The transport efficiencies were 90% for the low energy injector and 100% for the new 4-MV injector. The beam Gaussian profile and radius (5 mm) remain the same through acceleration. Experimental results will be presented and compared with numerical simulations

Engineering development for a small-scale recirculator experiment

International Nuclear Information System (INIS)

Newton, M.A.; Deadrick, F.J.; Hanks, R.L.; Hawkins, S.A.; Holm, K.A.; Kirbie, H.C.; Karpenko, V.P.; Nattrass, L.A.; Longinotti, D.B.

1995-01-01

Lawrence Livermore National Laboratory (LLNL) is evaluating the physics and technology of recirculating induction accelerators for heavy-ion inertial-fusion drivers. As part of this evaluation, the authors are building a small-scale recirculator to demonstrate the concept and to use as a test bed for the development of recirculator technologies. System designs have been completed and components are presently being designed and developed for the small-scale recirculator. This paper discusses results of the design and development activities that are presently being conducted to implement the small-scale recirculator experiments. An, overview of the system design is presented along with a discussion of the implications of this design on the mechanical and electrical hardware. The paper focuses primarily on discussions of the development and design of the half-lattice period hardware and the advanced solid-state modulator

Stability of the particle transverse motion in an electron linear accelerator with beam recirculation

International Nuclear Information System (INIS)

Volodin, V.A.

1979-01-01

Conditions, under which beam transverse instabilities appear in the electron linear accelerator (ELA) with a double particle acceleration due to excitation of asymmetric stray waves in the accelerating waveguide, and their peculiarities have been investigated. It is shown that in the ELA with beam recirculation the conditions under which the beam transverse instability appears can be determined with the help of the ''interaction function'' which depends on both the accelerating structure and the focusing in the beam transport channel. Comparison is made with characteristics of this phenomenon in conventional ELA, and possible reasons for the decrease of a starting current in ELA with recirculation are shown

Development of technique to apply induction heating stress improvement to recirculation inlet nozzle

International Nuclear Information System (INIS)

Chiba, Kunihiko; Nihei, Kenichi; Ootaka, Minoru

2009-01-01

Stress corrosion cracking (SCC) have been found in the primary loop recirculation (PLR) systems of boiling water reactors (BWR). Residual stress in welding heat-affected zone is one of the factors of SCC, and the residual stress improvement is one of the most effective methods to prevent SCC. Induction heating stress improvement (IHSI) is one of the techniques to improve reduce residual stress. However, it is difficult to apply IHSI to the place such as the recirculation inlet nozzle where the flow stagnates. In this present study, the technique to apply IHSI to the recirculation inlet nozzle was developed using water jet which blowed into the crevice between the nozzle safe end and the thermal sleeve. (author)

Linear fixed-field multipass arcs for recirculating linear accelerators

Directory of Open Access Journals (Sweden)

V. S. Morozov

2012-06-01

Full Text Available Recirculating linear accelerators (RLA’s provide a compact and efficient way of accelerating particle beams to medium and high energies by reusing the same linac for multiple passes. In the conventional scheme, after each pass, the different energy beams coming out of the linac are separated and directed into appropriate arcs for recirculation, with each pass requiring a separate fixed-energy arc. In this paper we present a concept of an RLA return arc based on linear combined-function magnets, in which two and potentially more consecutive passes with very different energies are transported through the same string of magnets. By adjusting the dipole and quadrupole components of the constituting linear combined-function magnets, the arc is designed to be achromatic and to have zero initial and final reference orbit offsets for all transported beam energies. We demonstrate the concept by developing a design for a droplet-shaped return arc for a dogbone RLA capable of transporting two beam passes with momenta different by a factor of 2. We present the results of tracking simulations of the two passes and lay out the path to end-to-end design and simulation of a complete dogbone RLA.

Diagnostics for induction accelerators

International Nuclear Information System (INIS)

Fessenden, T.J.

1996-04-01

The induction accelerator was conceived by N. C. Christofilos and first realized as the Astron accelerator that operated at LLNL from the early 1960's to the end of 1975. This accelerator generated electron beams at energies near 6 MeV with typical currents of 600 Amperes in 400 ns pulses. The Advanced Test Accelerator (ATA) built at Livermore's Site 300 produced 10,000 Ampere beams with pulse widths of 70 ns at energies approaching 50 MeV. Several other electron and ion induction accelerators have been fabricated at LLNL and LBNL. This paper reviews the principal diagnostics developed through efforts by scientists at both laboratories for measuring the current, position, energy, and emittance of beams generated by these high current, short pulse accelerators. Many of these diagnostics are closely related to those developed for other accelerators. However, the very fast and intense current pulses often require special diagnostic techniques and considerations. The physics and design of the more unique diagnostics developed for electron induction accelerators are presented and discussed in detail

Induction sensor for measuring the accelerating voltage in an iron-free induction accelerator

International Nuclear Information System (INIS)

Bol'nykh, N.S.; Il'in, Yu.M.; Kostyushok, A.A.; Suvorov, V.A.

1987-01-01

An inductive sensor is described for measuring the amplitude and form of the accelerating-voltage pulse in the storage coils in a radial iron-free linear induction accelerator. The sensor does not respond to interference from external fields and does not require adjustment after calibration

Diagnostics for induction accelerators

International Nuclear Information System (INIS)

Fessenden, T.J.

1997-01-01

The induction accelerator was conceived by N. C. Christofilos and first realized as the Astron accelerator that operated at Lawrence Livermore National Laboratory (LLNL) from the early 1960s to the end of 1975. This accelerator generated electron beams at energies near 6 MeV with typical currents of 600 Amperes in 400-ns pulses. The Advanced Test Accelerator (ATA) built at Livermore close-quote s Site 300 produced 10,000-Ampere beams with pulse widths of 70 ns at energies approaching 50 MeV. Several other electron and ion induction accelerators have been fabricated at LLNL and Lawrence Berkeley National Laboratory (LBNL). This paper reviews the principal diagnostics developed through efforts by scientists at both laboratories for measuring the current, position, energy, and emittance of beams generated by these high-current, short-pulse accelerators. Many of these diagnostics are closely related to those developed for other accelerators. However, the very fast and intense current pulses often require special diagnostic techniques and considerations. The physics and design of the more unique diagnostics developed for electron induction accelerators are presented and discussed in detail. copyright 1997 American Institute of Physics

Linear Fixed-Field Multi-Pass Arcs for Recirculating Linear Accelerators

International Nuclear Information System (INIS)

Morozov, V.S.; Bogacz, S.A.; Roblin, Y.R.; Beard, K.B.

2012-01-01

Recirculating Linear Accelerators (RLA's) provide a compact and efficient way of accelerating particle beams to medium and high energies by reusing the same linac for multiple passes. In the conventional scheme, after each pass, the different energy beams coming out of the linac are separated and directed into appropriate arcs for recirculation, with each pass requiring a separate fixed-energy arc. In this paper we present a concept of an RLA return arc based on linear combined-function magnets, in which two and potentially more consecutive passes with very different energies are transported through the same string of magnets. By adjusting the dipole and quadrupole components of the constituting linear combined-function magnets, the arc is designed to be achromatic and to have zero initial and final reference orbit offsets for all transported beam energies. We demonstrate the concept by developing a design for a droplet-shaped return arc for a dog-bone RLA capable of transporting two beam passes with momenta different by a factor of two. We present the results of tracking simulations of the two passes and lay out the path to end-to-end design and simulation of a complete dog-bone RLA.

Optics of beam recirculation in the CEBAF [Continuous Electron Beam Accelerator Facility] cw linac

International Nuclear Information System (INIS)

Douglas, D.R.

1986-01-01

The use of recirculation in linear accelerator designs requires beam transport systems that will not degrade beam quality. We present a design for the transport lines to be used during recirculation in the CEBAF accelerator. These beam lines are designed to avoid beam degradation through synchrotron radiation excitation or betatron motion mismatch, are insensitive to errors commonly encountered during beam transport, and are optimized for electron beams with energies of 0.5 to 6.0 GeV. Optically, they are linearly isochronous second order achromats based on a ''missing magnet'' FODO structure. We give lattice specifications for, and results of analytic estimates and numerical simulations of the performance of, the beam transport system

Experiments investigating the effects of the accelerating gap voltage pulse on the ion focused (IFR) high current electron recirculators

International Nuclear Information System (INIS)

Mazarakis, M.G.; Smith, D.L.; Poukey, J.W.; Wagner, J.S.; Bennett, L.F.; Olson, W.R. Turnman, B.N.; Prestwich, K.R.; Wells, J.

1991-01-01

The lifetime of the Ion Focusing Regime (IFR) channel following the pulsing of the post-accelerating gaps is critical for an open-ended, spiral recirculating electron linear accelerator. It dictates the number of allowable beam recirculations through the gap. In the case of a racetrack configuration, its is significant but not as critical, since the presence of the electron beam focuses the ions and lengthens the lifetime of the ion channel. It was established that pulsing the accelerating gap perturbs the IFR channel. However, for the parameters studied, the lifetime is long enough to allow at least four beam recirculations in a spiral device. In addition, cusp fields positioned upstream and downstream from the gap prevent it from perturbing the IFR channel

Experiments investigating the effects of the accelerating gap voltage pulse on the ion focused (IFR) high current electron recirculators

International Nuclear Information System (INIS)

Mazarakis, M.G.; Smith, D.L.; Poukey, J.W.; Wagner, J.S.; Bennett, L.F.; Olson, W.R.; Turman, B.N.; Prestwich, K.R.; Wells, J.

1991-01-01

The lifetime of the Ion Focusing Regime (IFR) channel following the pulsing of the post-accelerating gaps is critical for an open-ended, spiral recirculating electron linear accelerator. It dictates the number of allowable beam recirculations through the gap. In the case of a racetrack configuration, it is significant but not as critical, since the presence of the electron beam focuses the ions and lengthens the lifetime of the ion channel. It was established that pulsing the accelerating gap perturbs the IFR channel. However, for the parameters studied, the lifetime is long enough to allow at least four beam recirculations in a spiral device. In addition, cusp fields positioned upstream and downstream from the gap prevent it from perturbing the IFR channel. 4 refs., 5 figs., 1 tab

A high-current racetrack induction accelerator

International Nuclear Information System (INIS)

Mondelli, A.; Roberson, C.W.

1983-01-01

In this paper, the energy and system scaling laws of the Racetrack Induction Accelerator are determined and its operating principles are discussed. This device is a cyclic accelerator that is capable of multi-kiloamp operation. Long pulse induction linac technology is used to obtain short acceleration times. The accelerator consists of a long-pulse linear induction module and a racetrack beam transport system. For detailed studies of the particle dynamics in a racetrack, a numerical model is required to integrate the fully-relativistic single-particle equations of motion in an externally applied magnetic field. The numerical model is a compromise between the need for a large rotational transform and the need for a reasonable volume within the separatrix

Linear induction accelerator

Science.gov (United States)

Buttram, M.T.; Ginn, J.W.

1988-06-21

A linear induction accelerator includes a plurality of adder cavities arranged in a series and provided in a structure which is evacuated so that a vacuum inductance is provided between each adder cavity and the structure. An energy storage system for the adder cavities includes a pulsed current source and a respective plurality of bipolar converting networks connected thereto. The bipolar high-voltage, high-repetition-rate square pulse train sets and resets the cavities. 4 figs.

High power millimeter-wave free electron laser based on recirculating electrostatic accelerator

International Nuclear Information System (INIS)

Lee, Byung-Cheol; Kim, Sun-Kook; Jeong, Young-Uk; Cho, Sung-Oh; Lee, Jongmin

1995-01-01

Progress in the development of a high power, millimeter-wave free electron laser driven by a recirculating electrostatic accelerator is reported. The energy and the current of electron beam are 430 keV and 2 A, respectively. The expected average output power is above 10 kW at the wavelength of 3-10 mm. Minimizing of the beam loss is a key issue for CW operation of the FEL with high efficiency. (author)

Beam transport physics issues for the recirculating linear accelerator

International Nuclear Information System (INIS)

Shokair, I.R.

1992-11-01

The Recirculating Linear Accelerator (RLA) utilizes the Ion Focused Regime (IFR) of beam transport plus a ramped bending field to guide the beam around the curved sections. Several issues of beam transport are considered. Beam transverse perturbations that could result in growth of the ion hose instability are analyzed. It is found that transverse kicks due to bending field errors, energy mismatches and fringe fields are the most important. The scaling of these perturbations with beam and channel parameters is derived. The effect of ramping of the bending field on the preformed plasma channel is then considered. For RLA experimental parameters the effect is found to be very small. For high energies however, in addition to axial heating, it is found that ramping the field causes compression of the plasma channel along the radius of curvature. This compression results in a quasi-equilibrium plasma electron temperature along the field lines which leads to collisionless transport towards the walls. The analysis of compression is done in an approximate way using a single particle picture and the channel expansion is analyzed using an envelope solution which gives a simple expression for the expansion time. This solution is then verified by Buckshot simulations. For a bending field of 2 kG ramped in 2 μ-secs and an argon channel (RLA parameters) we estimate that the channel radius doubling time (along field lines) is of the order of 0.5 μ-secs. Finally the effect of electron impact ionization due to axially heated electrons by the action of the inductive field is estimated. It is found that in Argon gas the electron avalanche time could be as low as 0.5 μ-sec which is smaller than the field ramp time

Induction accelerator development for heavy ion fusion

International Nuclear Information System (INIS)

Reginato, L.L.

1993-05-01

For approximately a decade, the Heavy Ion Fusion Accelerator Research (HIFAR) group at LBL has been exploring the use of induction accelerators with multiple beams as the driver for inertial fusion targets. Scaled experiments have investigated the transport of space charge dominated beams (SBTE), and the current amplification and transverse emittance control in induction linacs (MBE-4) with very encouraging results. In order to study many of the beam manipulations required by a driver and to further develop economically competitive technology, a proposal has been made in partnership with LLNL to build a 10 MeV accelerator and to conduct a series of experiments collectively called the Induction Linac System Experiments (ILSE). The major components critical to the ILSE accelerator are currently under development. We have constructed a full scale induction module and we have tested a number of amorphous magnetic materials developed by Allied Signal to establish an overall optimal design. The electric and magnetic quadrupoles critical to the transport and focusing of heavy ion beams are also under development The hardware is intended to be economically competitive for a driver without sacrificing any of the physics or performance requirements. This paper will concentrate on the recent developments and tests of the major components required by the ILSE accelerator

Induction accelerator development for heavy ion fusion

International Nuclear Information System (INIS)

Reginato, L.L.

1993-05-01

For approximately a decade, the Heavy Ion Fusion Accelerator Research (HIFAR) group at LBL has been exploring the use of induction accelerators with multiple beams as the driver for inertial fusion targets. Scaled experiments have investigated the transport of space charge dominated beams (SBTE), and the current amplification and transverse emittance control in induction linacs (MBE-4) with very encouraging results. In order to study many of the beam manipulations required by a driver and to further develop economically competitive technology, a proposal has been made in partnership with LLNL to build a 10 MeV accelerator and to conduct a series of experiments collectively called the Induction Linac System Experiments (ILSE).The major components critical to the ILSE accelerator are currently under development. We have constructed a full scale induction module and we have tested a number of amorphous magnetic materials developed by Allied Signal to establish an overall optimal design. The electric and magnetic quadrupoles critical to the transport and focusing of heavy ion beams are also under development. The hardware is intended to be economically competitive for a driver without sacrificing any of the physics or performance requirements. This paper will concentrate on the recent developments and tests of the major components required by the ILSE accelerator

Dragon-I Linear Induction Electron Accelerator

International Nuclear Information System (INIS)

Ding Bonan; Deng Jianjun; Wang Huacen; Cheng Nian'an; Dai Guangsen; Zhang Linwen; Liu Chengjun; Zhang Wenwei; Li Jin; Zhang Kaizhi

2005-01-01

Dragon-I is a linear induction electron accelerator. This facility consists of a 3.6 MeV injector, 38 meter beam transport line and 16 MeV induction accelerator powered by high voltage generators, including 8 Marx generators and 48 Blumlein lines. This paper describes the physics design, development and experimental results of Dragon-I. The key technology is analyzed in the accelerator development, and the design requirements and operation of the major subsystems are presented. The experimental results show Dragon-I generates an 18-20 MeV, 2.5 kA, 70 ns electron beam. The X-ray spot size is about 1.2 mm and dose level about 0.103 C/kg at 1 meter. (authors)

Acceleration of aged-landfill stabilization by combining partial nitrification and leachate recirculation: A field-scale study

Energy Technology Data Exchange (ETDEWEB)

Chung, Jinwook [R& D Center, Samsung Engineering Co., Ltd., 415-10 Woncheon-dong, Youngtong-gu, Suwon, Gyeonggi-do 443-823 (Korea, Republic of); Kim, Seungjin; Baek, Seungcheon [Department of Civil and Environmental Engineering, Hanyang University, Sa 3-dong, Sangnok-gu, Ansan, Gyeonggi-do 426-791 (Korea, Republic of); Lee, Nam-Hoon [Department of Environmental & Energy Engineering, Anyang University, 22 Samdeok-ro, 37 Beon-gil, Manan-gu, Anyang, Gyeonggi-do 430-714 (Korea, Republic of); Park, Seongjun; Lee, Junghun; Lee, Heechang [Department of Civil and Environmental Engineering, Hanyang University, Sa 3-dong, Sangnok-gu, Ansan, Gyeonggi-do 426-791 (Korea, Republic of); Bae, Wookeun, E-mail: wkbae@hanyang.ac.kr [Department of Civil and Environmental Engineering, Hanyang University, Sa 3-dong, Sangnok-gu, Ansan, Gyeonggi-do 426-791 (Korea, Republic of)

2015-03-21

Highlights: • To solve the drawbacks (NH{sub 4}{sup +} accumulation) of leachate recirculation, ex-situ SBR was applied. • Produced NO{sub 2}{sup −} was recirculated and denitrified to N{sub 2} in landfill with insufficient carbon source. • Despite the inhibition of methanogenesis by DO and nitrate, CH{sub 4} fraction eventually increased. - Abstract: Leachate recirculation for rapid landfill stabilization can result in the accumulation of high-strength ammonium. An on-site sequencing batch reactor (SBR) was therefore, applied to oxidize the ammonium to nitrite, which was then recirculated to the landfill for denitrification to nitrogen gas. At relatively higher ammonium levels, nitrite accumulated well in the SBR; the nitrite was denitrified stably in the landfill, despite an insufficient biodegradable carbon source in the leachate. As the leachate was recirculated, the methane and carbon dioxide contents produced from the landfill fluctuated, implying that the organic acids and hydrogen produced in the acid production phase acted as the carbon source for denitrification in the landfill. Leachate recirculation combined with ex-situ partial nitrification of the leachate may enhance the biodegradation process by: (a) removing the nitrogen that is contained with the leachate, and (b) accelerating landfill stabilization, because the biodegradation efficiency of landfill waste is increased by supplying sufficient moisture and its byproducts are used as the carbon source for denitrification. In addition, partial nitrification using an SBR has advantages for complete denitrification in the landfill, since the available carbon source is in short supply in aged landfills.

Induction Acceleration of a Single RF Bunch in the KEK PS

CERN Document Server

Takayama, Ken; Arakida, Yoshio; Horioka, Kazuhiko; Igarashi, Susumu; Iwashita, Taiki; Kawasaki, Atsushi; Kishiro, Junichi; Kono, Tadaaki; Koseki, Kunio; Nakamura, Eiji; Sakuda, Makoto; Sato, Hikaru; Shiho, Makoto; Shimosaki, Yoshito; Shirakata, Masashi; Sueno, Tsuyoshi; Tokuchi, Akira; Torikai, Kota; Toyama, Takeshi; Wake, Masayoshi; Watanabe, Masao; Yamane, Isao

2005-01-01

A single bunch trapped in an RF bucket was accelerated by induction devices from 500 MeV to 8GeV beyond transition energy in the KEK-PS. This is the first demonstration of induction acceleration in a high energy circular ring. The acceleration was confirmed by measuring a temporal evolution of the RF phase through an entire acceleration.* Key devices in an induction acceleration system are an induction accelerating cavity capable of generating an induced voltage of 2kV/cell, a pulse modulator to drive the cavity (switching driver), and a DSP system to control gate signals for switching. Their remarkable characteristics are its repetition ratio of about 1MHz and duty factor of 50%. All devices have been newly developed at KEK so as to meet this requirement. The pulse modulator employing MOSFETs as switching elements is connected with the accelerating cavity through a long transmission cable in order to avoid a high-dose irradiation in the accelerator tunnel. The induction system has been running beyond more th...

Parameter choices for a muon recirculating linear accelerator from 5 to 63 GeV

Energy Technology Data Exchange (ETDEWEB)

Berg, J. S. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

2014-06-19

A recirculating linear accelerator (RLA) has been proposed to accelerate muons from 5 to 63 GeV for a muon collider. It should be usable both for a Higgs factory and as a stage for a higher energy collider. First, the constraints due to the beam loading are computed. Next, an expression for the longitudinal emittance growth to lowest order in the longitudinal emittance is worked out. After finding the longitudinal expression, a simplified model that describes the arcs and their approximate expression for the time of flight dependence on energy in those arcs is found. Finally, these results are used to estimate the parameters required for the RLA arcs and the linac phase.

Induction Accelerator Efficiency at 5 Hz

International Nuclear Information System (INIS)

Molvik, A.W.; Faltens, A.

2000-01-01

We simulate fusion power plant driver efficiency by pulsing small induction cores at 5 Hz (a typical projected power plant repetition rate), with a resistive load in the secondary winding that is scaled to simulate the beam loading for induction acceleration. Starting from a power plant driver design that is based on other constraints, we obtain the core mass and acceleration efficiency for several energy ranges of the driver accelerator and for three magnetic alloys. The resistor in the secondary is chosen to give the same acceleration efficiency, the ratio of beam energy gain to energy input to the core module (core plus acceleration gap), as was computed for the driver. The pulser consists of a capacitor switched by FETs, Field Effect Transistors, which are gated on for the desired pulse duration. The energy to the resistor is evaluated during the portion of the pulse that is adequately flat. We present data over a range of 0.6 to 5 μs pulse lengths. With 1 μs pulses, the acceleration efficiency at 5 Hz is measured to be 75%, 52%, and 32% for thin-tape-wound cores of nanocrystalline, amorphous, and 3% silicon steel materials respectively, including only core losses. The efficiency increases for shorter pulse durations

Induction accelerator test module for HIF

International Nuclear Information System (INIS)

Faltens, A.

1991-04-01

An induction linac test module suitable for investigating the drive requirements and the longitudinal coupling impedance of a high-power ion induction linac has been constructed by the Heavy Ion Fusion (HIF) group at LBL. The induction linac heavy ion driver for inertial confinement fusion (ICF) as presently envisioned uses multiple parallel beams which are transported in separate focusing channels but accelerated together in the induction modules. The resulting induction modules consequently have large beam apertures-1--2 meters in diameter- and correspondingly large outside diameters. The module geometry is related to a low-frequency ''gap capacity'' and high-frequency structural resonances, which are affected by the magnetic core loading and the module pulser impedance. A description of the test module and preliminary results are presented. 3 figs

Undulative induction electron accelerator for the waste and natural water purification systems

CERN Document Server

Kulish, Victor V; Gubanov, I V

2001-01-01

The project analysis of Undulative Induction Accelerator (EH - accelerator) for the waste and natural water purification systems is accomplished. It is shown that the use of the four-channel design of induction block and the standard set of auxiliary equipment (developed earlier for the Linear Induction Accelerators - LINACs) allow to construct commercially promising purification systems. A quality analysis of the accelerator is done and the optimal parameters are chosen taking into account the specific sphere of its usage.

Investigation of induction cells and modulator design for heavy ion accelerators

International Nuclear Information System (INIS)

Fong, C.G.; Reginato, L.R.

1992-01-01

The induction linear accelerator has been a leading candidate in the U.S. for the acceleration of high current heavy ion beams to initiate inertial confinement fusion (ICF). This paper describes the rather unique parameters derived from the accelerator beam dynamics, and addresses the design and development of accelerator induction cells and their modulators to be used in a near-term driver scaling experiment named the Induction Linac Systems Experiments (ILSE) planned for construction starting in 1994. Work is underway to develop the cells and their pulse modulators. Tradeoffs between the amorphous core material, pulse length, rise and fall time are made against efficiency, costs and technical risks are discussed

Linear induction accelerator for heavy ions

International Nuclear Information System (INIS)

Keefe, D.

1976-01-01

There is considerable recent interest in the use of high energy heavy ions to irradiate deuterium-tritium pellets in a reactor vessel to constitute a power source at the level of 1 GW or more. Various accelerator configurations involving storage rings have been suggested. This paper discusses how the technology of linear induction accelerators - well known to be matched to high current and short pulse length - may offer significant advantages for this application. (author)

Induction accelerators for the phase rotator system

International Nuclear Information System (INIS)

Reginato, Lou; Yu, Simon; Vanecek, Dave

2001-01-01

The principle of magnetic induction has been applied to the acceleration of high current beams in betatrons and a variety of induction accelerators. The linear induction accelerator (LIA) consists of a simple nonresonant structure where the drive voltage is applied to an axially symmetric gap that encloses a toroidal ferromagnetic material. The change in flux in the magnetic core induces an axial electric field that provides particle acceleration. This simple nonresonant (low Q) structure acts as a single turn transformer that can accelerate from hundreds of amperes to tens of kiloamperes, basically only limited by the drive impedance. The LIA is typically a low gradient structure that can provide acceleration fields of varying shapes and time durations from tens of nanoseconds to several microseconds. The efficiency of the LIA depends on the beam current and can exceed 50% if the beam current exceeds the magnetization current required by the ferromagnetic material. The acceleration voltage available is simply given by the expression V=A dB/dt. Hence, for a given cross section of material, the beam pulse duration influences the energy gain. Furthermore, a premium is put on minimizing the diameter, which impacts the total weight or cost of the magnetic material. The diameter doubly impacts the cost of the LIA since the power (cost) to drive the cores is proportional to the volume as well. The waveform requirements during the beam pulse makes it necessary to make provisions in the pulsing system to maintain the desired dB/dt during the useful part of the acceleration cycle. This is typically done two ways, by using the final stage of the pulse forming network (PFN) and by the pulse compensation network usually in close proximity of the acceleration cell. The choice of magnetic materials will be made by testing various materials both ferromagnetic and ferrimagnetic. These materials will include the nickel-iron, silicon steel amorphous and various types of ferrites not

The design of the accelerating gaps for the linear induction accelerator RADLAC II

International Nuclear Information System (INIS)

Shope, S.L.; Mazarakis, M.G.; Miller, R.B.; Poukey, J.W.

1987-01-01

In high current (50 kA) linear induction accelerators, the accelerating gaps can excite large radial oscillations. A gap was designed that minimized the radial oscillations and reduced potential depressions. The envelope equation predicted radial oscillation amplitudes of 1 mm which agreed with experimental measurements

Long-pulse induction acceleration of heavy ions

International Nuclear Information System (INIS)

Faltens, A.; Firth, M.; Keefe, D.; Rosenblum, S.S.

1983-03-01

A long-pulse induction acceleration unit has been installed in the high-current Cs + beam line at LBL and has accelerated heavy ions. A maximum energy gain of 250 keV for 1.5 μs is possible. The unit comprises 12 independent modules which may be used to synthesize a variety of waveforms by varying the triggering times of the low-voltage trigger generators

Long-pulse induction acceleration of heavy ions

International Nuclear Information System (INIS)

Faltons, A.; Firth, M.; Keefe, D.; Rosenblum, S.

1983-01-01

A long-pulse induction acceleration unit has been installed in the high-current Cs + beam line at LBL and has accelerated heavy ions. A maximum energy gain of 250 keV for 1.5 μs is possible. The unit comprises 12 independent modules which may be used to synthesize a variety of waveforms by varying the triggering times of the low voltage trigger generators

Long-pulse induction acceleration of heavy-ions

International Nuclear Information System (INIS)

Faltens, A.; Firth, M.; Keefe, D.; Rosenblum, S.S.

1983-01-01

A long-pulse induction acceleration unit has been installed in the high-current Cs + beam line at LBL and has accelerated heavy ions. A maximum energy gain of 250 keV for 1.5 μs is possible. The unit comprises 12 independent modules which may be used to synthesize a variety of waveforms by varying the triggering times of the low voltage trigger generators

Linear induction accelerator for heavy ions

International Nuclear Information System (INIS)

Keefe, D.

1976-09-01

There is considerable recent interest in the use of high energy (γ = 1.1), heavy (A greater than or equal to 100) ions to irradiate deuterium--tritium pellets in a reactor vessel to constitute a power source at the level of 1 GW or more. Various accelerator configurations involving storage rings have been suggested. A discussion is given of how the technology of Linear Induction Accelerators--well known to be matched to high current and short pulse length--may offer significant advantages for this application

Induction linear accelerators with high-Tc bulk superconductor lenses

International Nuclear Information System (INIS)

Matsuzawa, Hidenori; Wada, Haruhisa; Mori, Satoshi; Yamamoto, Tadashi

1991-01-01

Solenoidal coils in a one-stage induction accelerator were replaced by a high-T c bulk superconductor lens (Supertron). The accelerator postaccelerated injected electron beams to ∼ 400 keV, ∼ 0.35 kA, and ∼ 10 ns of duration time. (author)

Core reset system design for linear induction accelerator

International Nuclear Information System (INIS)

Durga Praveen Kumar, D.; Mitra, S.; Sharma, Archana; Nagesh, K.V.; Chakravarthy, D.P.

2006-01-01

A repetitive pulsed power system based Linear Induction Accelerator (LIA-200) is being developed at BARC to get an electron beam of 200keV, 5kA, 50ns, 10-100 Hz. Amorphous core is the heart of these accelerators. It serves various functions in different subsystems viz. pulse power modulator, pulse transformer, magnetic switches and induction cavities. One of the factors that make the magnetic components compact is utilization of the total flux swing available in the core. In the present system, magnetic switches, pulse transformers, and induction cavity are designed to avail the full flux swing available in the core. For achieving this objective, flux density in the core has to be kept at the reverse saturation, before the main pulse is applied. The electrical circuit which makes it possible is called the core reset system. In this paper the details of core reset system designed for LIA-200 are described. (author)

MHz repetition rate solid-state driver for high current induction accelerators

International Nuclear Information System (INIS)

Brooksby, C; Caporaso, G; Goerz, D; Hanks, R; Hickman, B; Kirbie, H; Lee, B; Saethre, R.

1999-01-01

A research team from the Lawrence Livermore National Laboratory and Bechtel Nevada Corporation is developing an all solid-state power source for high current induction accelerators. The original power system design, developed for heavy-ion fusion accelerators, is based on the simple idea of using an array of field effect transistors to switch energy from a pre-charged capacitor bank to an induction accelerator cell. Recently, that idea has been expanded to accommodate the greater power needs of a new class of high-current electron accelerators for advanced radiography. For this purpose, we developed a 3-stage induction adder that uses over 4,000 field effect transistors to switch peak voltages of 45 kV at currents up to 4.8 kA with pulse repetition rates of up to 2 MHz. This radically advanced power system can generate a burst of five or more pulses that vary from 200 ns to 2 ampersand micro;s at a duty cycle of up to 25%. Our new source is precise, robust, flexible, and exceeds all previous drivers for induction machines by a factor of 400 in repetition rate and a factor of 1000 in duty cycle

Induction linear accelerator technology for SDIO applications

International Nuclear Information System (INIS)

Birx, D.; Reginato, L.; Rogers, D.; Trimble, D.

1986-11-01

The research effort reported concentrated primarily on three major activities. The first was aimed at improvements in the accelerator drive system of an induction linac to meet the high repetition rate requirements of SDI applications. The second activity centered on a redesign of the accelerator cells to eliminate the beam breakup instabilities, resulting in optimized beam transport. The third activity sought to improve the source of electrons to achieve a higher quality beam to satisfy the requirement of the free electron laser

Experimental research of double-pulse linear induction electron accelerator

International Nuclear Information System (INIS)

Liao Shuqing; Cheng Cheng; Zheng Shuxin; Tang Chuanxiang; Lin Yuzheng; Jing Xiaobing; Mu Fan; Pan Haifeng

2009-01-01

The Mini-LIA is a double-pulse linear induction electron accelerator with megahertz repetition rates, which consists of a double-pulse power system, a thermal cathode electron gun, two induction cells, beam transportation systems and diagnosis systems, etc. Experiments of the Mini-LIA have been conducted. The double-pulse high voltage was obtained with several hundred nanosecond pulse intervals (i. e. megahertz repetition rate) and each pulse had an 80 kV amplitude with a FWHM of 80 ns. In the gap of the induction cell, the double-pulse accelerating electric field was measured via E-field probes, and the double-pulse electron beam with a current about 1.1 A has been obtained at the Mini-LIA exit. These experimental results show that the double-pulse high voltage with megahertz repetition rates can be generated by an insulation and junction system. And they also indicate that the induction cell with metglas as the ferromagnetic material and the LaB 6 thermal cathode electron gun suit the double-pulse operation with megahertz repetition rates. (authors)

VoxHenry: FFT-Accelerated Inductance Extraction for Voxelized Geometries

KAUST Repository

Yucel, Abdulkadir C.

2018-01-18

VoxHenry, a fast Fourier transform (FFT)-accelerated integral-equation-based simulator for extracting frequency-dependent inductances and resistances of structures discretized by voxels, is presented. VoxHenry shares many features with the popular inductance extractor, FastHenry. Just like FastHenry, VoxHenry solves a combination of the electric volume integral equation and the current continuity equation, but with three distinctions that make VoxHenry suitable and extremely efficient for analyzing voxelized geometries: 1) it leverages a carefully selected set of piecewise-constant and piecewise-linear basis functions; 2) it exploits FFTs to accelerate the matrix-vector multiplications during the iterative solution of system of equations; and 3) it employs a sparse preconditioner to ensure the rapid convergence of iterative solution. VoxHenry is capable of accurately computing frequency-dependent inductances and resistances of arbitrarily shaped and large-scale structures on a desktop computer. The accuracy, efficiency, and applicability of VoxHenry are demonstrated through inductance analysis of various structures, including square and circular coils as well as arrays of RF inductors (situated over ground planes).

''Theta gun,'' a multistage, coaxial, magnetic induction projectile accelerator

International Nuclear Information System (INIS)

Burgess, T.J.; Duggin, B.W.; Cowan, M. Jr.

1985-11-01

We experimentally and theoretically studied a multistage coaxial magnetic induction projectile accelerator. We call this system a ''theta gun'' to differentiate it from other coaxial accelerator concepts such as the mass driver. We conclude that this system can theoretically attain railgun performance only for large caliber or very high injection velocity and, even then, only for long coil geometry. Our experiments with a three-stage, capactor bank-driven accelerator are described. The experiments are modeled with a 1-1/2 dimensional equivalent circuit-hydrodynamics code which is also described. We derive an expression for the conditions of coaxial accelerator-railgun ''velocity breakeven'' in the absence of ohmic and hydrodynamic effects. This, in conjunction with an expression for the magnetic coupling coefficient, defines a set of geometric relations which the coaxial system must simultaneously satisfy. Conclusions concerning both the existence and configuration of a breakeven coaxial system follow from this requirement. The relative advantages and disadvantages of the coaxial induction projectile accelerator, previously cited in the literature, are critiqued from the viewpoint of our analysis and experimental results. We find that the advantages vis-a-vis the railgun have been overstated. 13 refs., 17 figs

Linear induction accelerator and pulse forming networks therefor

Science.gov (United States)

Buttram, Malcolm T.; Ginn, Jerry W.

1989-01-01

A linear induction accelerator includes a plurality of adder cavities arranged in a series and provided in a structure which is evacuated so that a vacuum inductance is provided between each adder cavity and the structure. An energy storage system for the adder cavities includes a pulsed current source and a respective plurality of bipolar converting networks connected thereto. The bipolar high-voltage, high-repetition-rate square pulse train sets and resets the cavities.

Induction-accelerator heavy-ion fusion: Status and beam physics issues

International Nuclear Information System (INIS)

Friedman, A.

1996-01-01

Inertial confinement fusion driven by beams of heavy ions is an attractive route to controlled fusion. In the U.S., induction accelerators are being developed as open-quotes driversclose quotes for this process. This paper is divided into two main sections. In the first section, the concept of induction-accelerator driven heavy-ion fusion is briefly reviewed, and the U.S. program of experiments and theoretical investigations is described. In the second, a open-quotes taxonomyclose quotes of space-charge-dominated beam physics issues is presented, accompanied by a brief discussion of each area

Transport and error sensitivity in a heavy-ion recirculator

International Nuclear Information System (INIS)

Sharp, W.M.; Barnard, J.J.; Yu, S.S.

1991-05-01

An envelope code has been developed to facilitate the design of a recirculating accelerator for a heavy-ion fusion reactor. A novel feature of the model is the treatment of the beam charge density as a Lagrangian fluid in the axial direction. Transport results for a preliminary recirculator design are presented, and sensitivity of the transport to errors in the magnet strength is discussed. 4 refs., 4 figs

Linear induction accelerators for fusion and neutron production

International Nuclear Information System (INIS)

Barletta, W.A.; California Univ., Los Angeles, CA

1993-08-01

Linear induction accelerators (LIA) with pulsed power drives can produce high energy, intense beams or electrons, protons, or heavy ions with megawatts of average power. The continuing development of highly reliable LIA components permits the use such accelerators as cost-effective beam sources to drive fusion pellets with heavy ions, to produce intense neutron fluxes using proton beams, and to generate with electrons microwave power to drive magnetic fusion reactors and high gradient, rf-linacs

Cell design for the DARHT linear induction accelerators

International Nuclear Information System (INIS)

Burns, M.; Allison, P.; Earley, L.; Liska, D.; Mockler, C.; Ruhe, J.; Tucker, H.; Walling, L.

1991-01-01

The Dual-Axis Radiographic Hydrotest (DARHT) facility will employ two linear induction accelerators to produce intense, bremsstrahlung x- ray pulses for flash radiography. The accelerator cell design for a 3- kA, 16--20 MeV, 60-ns flattop, high-brightness electron beam is presented. The cell is optimized for high-voltage stand-off while also minimizing the its transverse impedance. Measurements of high- voltage and rf characteristics are summarized. 7 refs., 5 figs

Technology demonstration for the DARHT linear induction accelerators

International Nuclear Information System (INIS)

Burns, M.; Allison, P.; Downing, J.; Moir, D.; Caporaso, G.; Chen, Y.J.

1992-01-01

The Dual-Axis Radiographic Hydrodynamics Test (DARHT) facility will employ two 16-MeV, 3-kA Linear Induction Accelerators to produce intense, bremsstrahlung x-ray pulses for flash radiography. Technology demonstration of the key accelerator sub-systems is underway at the DARHT Integrated Test Stand (ITS), which will produce a 6-MeV, 3-kA, 60-ns flattop electron beam. We will summarized measurements of ITS injector, pulsed-power, and accelerator cell performance. Time-resolved measurements of the electron beam parameters will also be presented. These measurements indicate that the DARHT accelerator design is sufficiently advanced to provide the high quality electron beams required for radiography with sub-millimeter spatial resolution

Technology demonstration for the DARHT linear induction accelerators

International Nuclear Information System (INIS)

Burns, M.; Allison, P.; Downing, J.; Moir, D.; Caporaso, G.; Chen, Y.J.

1993-01-01

The Dual-Axis Radiographic Hydrodynamics Test (DARHT) facility will employ two 16-MeV, 3-kA Linear Induction Accelerators to produce intense, bremsstrahlung x-ray pulses for flash radiography. Technology demonstration of the key accelerator sub-systems is underway at the DARHT Integrated Test Stand (ITS), which will produce a 6-MeV, 3-kA, 60-ns flattop electron beam. The authors summarize measurements of ITS injector, pulsed-power, and accelerator cell performance. Time-resolved measurements of the electron beam parameters are also presented. These measurements indicate that the DARHT accelerator design is sufficiently advanced to provide the high quality electron beams required for radiography with sub-millimeter spatial resolution

Beam breakup in a multi-section recirculating linac

International Nuclear Information System (INIS)

Gluckstern, R.L.

1986-01-01

It has long been recognized that recirculating a beam through a linac cavity in order to provide a more efficient acceleration can also lead to an instability in which the transverse displacement on successive recirculations can excite modes which further deflect the initial beam. The effect is of particular concern for superconducting rf cavities where the high Q (or order 10 9 ) implied low starting currents for the instability. Previous work has addressed this effect by calculating the beam trajectory in a single cavity, and its effect on excitation of unwanted modes. The analysis of Gluckstern, Cooper and Channel is extended to the case of recirculation of a CW beam, and the starting current for a multi-cavity structure with several recirculations is computed. Each of the cavities is assumed to provide a simple impulse to the beam proportional to the transverse displacement in that cavity

Circular induction accelerator for borehole logging

International Nuclear Information System (INIS)

Chen, F.K.; Bertozzi, W.; Corris, G.W.; Diamond, W.; Doucet, J.A.; Schweitzer, J.S.

1992-01-01

This patent describes a downhole logging sonde adapted to be moved through a borehole, a source of gamma rays in the sonde for irradiating earth formations traversed by the borehole, one or more gamma ray detectors for detecting gamma rays scattered back to the sonde from the irradiated earth formations, and means for transmitting signals representative of the detected gamma rays to the earth's surface for processing. This patent describes improvement in the gamma ray source comprises a magnetic induction particle accelerator, including: a magnetic circuit having a field magnet, generally circular opposed pole pieces, and a core magnet metal ions from the group consisting of Mn, Zn and Ni; an excitation circuit including a field coil surrounding the field magnet and the core magnet and a core coil surrounding the central axially leg of the core magnet; an annular acceleration chamber interposed between the pole pieces; means for applying time-varying acceleration voltage pulses across the primary excitation circuit; means for injecting charged particles into orbit within the acceleration chamber; means for compressing the particle orbits to trap particles within generally circular orbits within the acceleration chamber; means for generating a particle accelerating magnetic flux in the magnetic circuit; and means for ejecting charged particles from the generally circular orbits and into contact with a target to produce gamma ray photons

Optimization design of the main switch in 12 MeV linear induction accelerator

International Nuclear Information System (INIS)

Li Xin; Wang Jinsheng; Ding Hensong; Ye Yi

2004-01-01

A method for optimization design of the main switch (using in 12 MeV linear induction accelerator) was introduced. The switch's inductance was decreased from 63.7 nH to 35 nH by optimizing the configuration of the main switch and the size of the electric poles so that the accelerating cavity can get a better rising time of 27 ns. The accelerator's performance can be effectively improved through this method, the feasibility of the method is also proved by testing

Progress in heavy-ion drivers for inertial fusion

International Nuclear Information System (INIS)

Friedman, A.; Bangerter, R.O.; Herrmannsfeldt, W.B.

1994-01-01

Heavy-ion induction accelerators are being developed as fusion drivers for ICF power production in the US Inertial Fusion Energy (IFE) program, in the Office of Fusion Energy of the US Department of Energy. In addition, they represent an attractive driver option for a high-yield microfusion facility for defense research. This paper describes recent progress in induction drivers for Heavy-Ion Fusion (HIF), and plans for future work. It presents research aimed at developing drivers having reduced cost and size, specifically advanced induction linacs and recirculating induction accelerators (recirculators). The goals and design of the Elise accelerator being built at Lawrence Berkeley Laboratory (LBL), as the first stage of the ILSE (Induction Linac Systems Experiments) program, are described. Elise will accelerate, for the first time, space-charge-dominated ion beams which are of full driver scale in line-charge density and diameter. Elise will be a platform on which the critical beam manipulations of the induction approach can be explored. An experimental program at Lawrence Livermore National Laboratory (LLNL) exploring the recirculator principle on a small scale is described in some detail; it is expected that these studies will result ultimately in an operational prototype recirculating induction accelerator. In addition, other elements of the US HIF program are described

Transverse emittance studies of an induction accelerator of heavy ions

International Nuclear Information System (INIS)

Garvey, T.; Eylon, S.; Fessenden, T.J.; Hahn, K.; Henestroza, E.

1991-01-01

Current amplification of heavy ion beams is an integral feature of the induction linac approach to heavy ion fusion. As part of the Heavy Ion Fusion Accelerator Research program at LBL the authors have been studying the evolution of the transverse emittance of ion beams while they are undergoing current amplification, achieved by longitudinal bunch compression and acceleration. Experiments are conducted on MBE-4, a four beam Cs + induction linac. The space-charge dominated beams of MBE-4 are focused by electrostatic quadrupoles while they are accelerated from nominally 200 keV up to ∼ 1 MEV by 24 accelerating gaps. Initially the beams have currents of typically 4 mA to 10 mA per beam. Early experimental results showed a growth of the normalized emittance by a factor of 2 while the beam current was amplified by up to 9 times its initial value. The authors will discuss the results of recent experiments in which a mild bunch length compression rate, more typical of that required by a fusion driver, has shown that the normalized emittance can be maintained at its injection value (0.03 mm-mr) during acceleration

Longitudinal instability of an induction linac with acceleration

International Nuclear Information System (INIS)

Smith, L.; Lee, E.P.

1993-05-01

The question arises as to what effect acceleration, which so far has been ignored, has on the longitudinal instability of an induction linac. The answer is not much for the anticipated acceleration rate (1--2 MeV/m) and minimum e-folding distance for the instability (50--500 meters). However, total unstable growth is significantly reduced over distances which are long enough for appreciable acceleration to occur. The purpose of this note is to record a calculation of the instability, including a constant acceleration rate. Some interesting features emerge -- for example, the velocity of the head is a more convenient independent variable than axial position and, for an initial sinusoidal perturbation of velocity in time, the number of oscillations along the pulse is constant; as the pulse shortens in nine the frequency increases

High average power linear induction accelerator development

International Nuclear Information System (INIS)

Bayless, J.R.; Adler, R.J.

1987-07-01

There is increasing interest in linear induction accelerators (LIAs) for applications including free electron lasers, high power microwave generators and other types of radiation sources. Lawrence Livermore National Laboratory has developed LIA technology in combination with magnetic pulse compression techniques to achieve very impressive performance levels. In this paper we will briefly discuss the LIA concept and describe our development program. Our goals are to improve the reliability and reduce the cost of LIA systems. An accelerator is presently under construction to demonstrate these improvements at an energy of 1.6 MeV in 2 kA, 65 ns beam pulses at an average beam power of approximately 30 kW. The unique features of this system are a low cost accelerator design and an SCR-switched, magnetically compressed, pulse power system. 4 refs., 7 figs

Optimum design for 12 MeV linear induction accelerator diode

International Nuclear Information System (INIS)

Yu Haijun; Shi Jinshui; Li Qin; He Guorong; Ma Bing; Wang Jingsheng; Wang Liping

2001-01-01

A series of optimization designs of electron diode in 12 Mev linear induction accelerator are studied by using numerical simulation code MAGIC and experiment method in order to improve the electron beam quality. MAGIC code solves the Maxwell equations in the presence of charged particle, electron field distribution on cathode surface which influences electron emission is given, the optimum diode is obtained by comparing the results of experiment in 12 MeV linear induction accelerator. The author also gives SEM analysis and experiment comparison of velvet emission. Finally, emitted current I e = 8.52 kA, beam current I 8 ≥ 3.0 kA, targeted current I 0 ≥ 2.30 kA with optimum diode are obtained

Effect of accelerating gap geometry on the beam breakup instability in linear induction accelerators

International Nuclear Information System (INIS)

Miller, R.B.; Marder, B.M.; Coleman, P.D.; Clark, R.E.

1988-01-01

The electron beam in a linear induction accelerator is generally susceptible to growth of the transverse beam breakup instability. In this paper we analyze a new technique for reducing the transverse coupling between the beam and the accelerating cavities, thereby reducing beam breakup growth. The basic idea is that the most worrisome cavity modes can be cutoff by a short section of coaxial transmission line inserted between the cavity structure and the accelerating gap region. We have used the three-dimensional simulation code SOS to analyze this problem. In brief, we find that the technique works, provided that the lowest TE mode cutoff frequency in the coaxial line is greater than the frequency of the most worrisome TM mode of the accelerating cavity

Scaling of induction-cell transverse impedance: effect on accelerator design

International Nuclear Information System (INIS)

Ekdahl, Carl August

2016-01-01

The strength of the dangerous beam breakup (BBU) instability in linear induction accelerators (LIAs) is characterized by the transverse coupling impedance Z ? . This note addresses the dimensional scaling of Z ? , which is important when comparing new LIA designs to existing accelerators with known i BBU growth. Moreover, it is shown that the scaling of Z ? with the accelerating gap size relates BBU growth directly to high-voltage engineering considerations. It is proposed to firmly establish this scaling though a series of AMOS calculations.

Numerical simulation on beam breakup unstability of linear induction accelerator

International Nuclear Information System (INIS)

Zhang Kaizhi; Wang Huacen; Lin Yuzheng

2003-01-01

A code is written to simulate BBU in induction linac according to theoretical analysis. The general form of evolution of BBU in induction linac is investigated at first, then the effect of related parameters on BBU is analyzed, for example, the alignment error, oscillation frequency of beam centroid, beam pulse shape and acceleration gradient. At last measures are put forward to damp beam breakup unstability (BBU)

Concept for high-charge-state ion induction accelerators

International Nuclear Information System (INIS)

Logan, B.G.; Perry, M.D.; Caporaso, G.J.

1996-01-01

This work describes a particular concept for ion induction linac accelerators using high-charge-state ions produced by an intense, short pulse laser, and compares the costs of a modular driver system producing 6.5 MJ for a variety of ion masses and charge states using a simple but consistent cost model

Beam dynamics simulation of a double pass proton linear accelerator

Directory of Open Access Journals (Sweden)

Kilean Hwang

2017-04-01

Full Text Available A recirculating superconducting linear accelerator with the advantage of both straight and circular accelerator has been demonstrated with relativistic electron beams. The acceleration concept of a recirculating proton beam was recently proposed [J. Qiang, Nucl. Instrum. Methods Phys. Res., Sect. A 795, 77 (2015NIMAER0168-900210.1016/j.nima.2015.05.056] and is currently under study. In order to further support the concept, the beam dynamics study on a recirculating proton linear accelerator has to be carried out. In this paper, we study the feasibility of a two-pass recirculating proton linear accelerator through the direct numerical beam dynamics design optimization and the start-to-end simulation. This study shows that the two-pass simultaneous focusing without particle losses is attainable including fully 3D space-charge effects through the entire accelerator system.

Determination of acceleration and stabilization indicators for buried municipal wastes. Study of leachates recirculation impact on waste columns; Determination d'indicateurs d'acceleration et de stabilisation de dechets menagers enfouis. Etude de l'impact de la recirculation de lixiviats sur colonnes de dechets

Energy Technology Data Exchange (ETDEWEB)

Francois, V

2004-05-15

The main goal of this research work was to study the stabilisation processes of municipal solid waste (MSW). Representative parameters, which are required to evaluate the stabilization state of wastes, were applied to study the acceleration of the degradation processes in lab-scale landfill anaerobic bioreactors operated with leachate recirculation. The characterisation of the wastes solid phase (i.e., volatile solids, organic carbon, fines, paper-cardboard and degraded component contents) is necessary to assess its degradation state. However, additional parameters are required such as the characterisation of water extracted from the waste (i.e., Chemical Oxygen Content (COD), Dissolved Oxygen Content (DOC) and ions content) and biogas composition (methane potential). Those parameters are nevertheless complementary to conclude on its polluting feature. The analysis of more specific indicators such as the organic macromolecules content in leachates and the evaluation of the metal contamination level in solid waste and its potential remobilization was showed to be consistent for the evaluation of waste stabilisation state. The composition of leachates used during recirculation influences greatly the waste leaching behaviour. For instance, the recirculation of a stabilised leachate containing organic macromolecules can increase the release of pollutants (organics and minerals) if contacted with young waste or on the other hand the release of pollutant is reduced when the leachate composition is similar to the organic species, which are expected to be released by the wastes. Due to the experimental limits of the leaching tests, several lab-scale landfill anaerobic bioreactors containing different wastes types (height of 1 m and mass of waste varying from 28 kg to 65 kg) were operated to study the effects of recirculation on the waste degradation at flow rate of 540 mL per day. The speed-up of waste degradation was clearly established from global parameters measured on

Linear induction accelerators made from pulse-line cavities with external pulse injection

International Nuclear Information System (INIS)

Smith, I.

1979-01-01

Two types of linear induction accelerator have been reported previously. In one, unidirectional voltage pulses are generated outside the accelerator and injected into the accelerator cavity modules, which contain ferromagnetic material to reduce energy losses in the form of currents induced, in parallel with the beam, in the cavity structure. In the other type, the accelerator cavity modules are themselves pulse-forming lines with energy storage and switches; parallel current losses are made zero by the use of circuits that generate bidirectional acceleration waveforms with a zero voltage-time integral. In a third type of design described here, the cavities are externally driven, and 100% efficient coupling of energy to the beam is obtained by designing the external pulse generators to produce bidirectional voltage waveforms with zero voltage-time integral. A design for such a pulse generator is described that is itself one hundred percent efficient and which is well suited to existing pulse power techniques. Two accelerator cavity designs are described that can couple the pulse from such a generator to the beam; one of these designs provides voltage doubling. Comparison is made between the accelerating gradients that can be obtained with this and the preceding types of induction accelerator

Linear induction accelerator approach for advanced radiography

International Nuclear Information System (INIS)

Caporaso, G.J.

1997-05-01

Recent advances in induction accelerator technology make it possible to envision a single accelerator that can serve as an intense, precision multiple pulse x-ray source for advanced radiography. Through the use of solid-state modulator technology repetition rates on the order of 1 MHz can be achieved with beam pulse lengths ranging from 200 ns to 2 microsecs. By using fast kickers, these pulses may be sectioned into pieces which are directed to different beam lines so as to interrogate the object under study from multiple lines of sight. The ultimate aim is to do a time dependent tomographic reconstruction of a dynamic object. The technology to accomplish these objectives along with a brief discussion of the experimental plans to verify it will be presented

Recirculating accelerator driver for a high-power free-electron laser: A design overview

International Nuclear Information System (INIS)

Bohn, C.L.

1997-01-01

Jefferson Lab is building a free-electron laser (FEL) to produce continuous-wave (cw), kW-level light at 3-6 μm wavelength. A superconducting linac will drive the laser, generating a 5 mA average current, 42 MeV energy electron beam. A transport lattice will recirculate the beam back to the linac for deceleration and conversion of about 75% of its power into rf power. Bunch charge will range up to 135 pC, and bunch lengths will range down to 1 ps in parts of the transport lattice. Accordingly, space charge in the injector and coherent synchrotron radiation in magnetic bends come into play. The machine will thus enable studying these phenomena as a precursor to designing compact accelerators of high-brightness beams. The FEL is scheduled to be installed in its own facility by 1 October 1997. Given the short schedule, the machine design is conservative, based on modifications of the CEBAF cryomodule and MIT-Bates transport lattice. This paper surveys the machine design

Recirculating accelerator driver for a high-power free-electron laser: A design overview

Energy Technology Data Exchange (ETDEWEB)

Bohn, C.L. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

1997-06-01

Jefferson Lab is building a free-electron laser (FEL) to produce continuous-wave (cw), kW-level light at 3-6 {mu}m wavelength. A superconducting linac will drive the laser, generating a 5 mA average current, 42 MeV energy electron beam. A transport lattice will recirculate the beam back to the linac for deceleration and conversion of about 75% of its power into rf power. Bunch charge will range up to 135 pC, and bunch lengths will range down to 1 ps in parts of the transport lattice. Accordingly, space charge in the injector and coherent synchrotron radiation in magnetic bends come into play. The machine will thus enable studying these phenomena as a precursor to designing compact accelerators of high-brightness beams. The FEL is scheduled to be installed in its own facility by 1 October 1997. Given the short schedule, the machine design is conservative, based on modifications of the CEBAF cryomodule and MIT-Bates transport lattice. This paper surveys the machine design.

Induction-linear accelerators for food processing with ionizing radiation

International Nuclear Information System (INIS)

Lagunas-Solar, M.C.

1985-01-01

Electron accelerators with sufficient beam power and reliability of operation will be required for applications in the large-scale radiation processing of food. Electron beams can be converted to the more penetrating bremsstrahlung radiation (X-rays), although at a great expense in useful X-ray power due to small conversion efficiencies. Recent advances in the technology of pulse-power accelerators indicates that Linear Induction Electron Accelerators (LIEA) are capable of sufficiently high-beam current and pulse repetition rate, while delivering ultra-short pulses of high voltage. The application of LIEA systems in food irradiation provides the potential for high product output and compact, modular-type systems readily adaptable to food processing facilities. (orig.)

Theory of mutation induction by accelerated very heavy ions in cells

International Nuclear Information System (INIS)

Kozubek, S.; Ryznar, L.

1995-01-01

Stochastic effects of ionising radiation in humans are related to mutation induction in cells. Therefore experimental data on mutation induction represents one of the endpoints used for the estimation of risk in radiation protection. Only very rough estimates can be made owing to the fact that a suitable theoretical approach does not exist. A simple method is proposed for the evaluation of the efficiency of mutation induction by accelerated very heavy ions in mammalian cells. The approach is based on the calculation of the fraction of energy deposited by accelerated particles in indirect collisions (hits) in the cells. Two different modes of particle mutagenic action can be distinguished. δ ray mutagenesis is related to those particles that preferentially kill the cells in direct hits. Track-core mutagenesis arises from direct hits and is observed for lighter ions or ions with very high energy (LET ≤ 500 keV.μm -1 ). Available experimental data agree reasonably well with the results based on theory. (author)

Post acceleration of a pseudospark-produced electron beam by an induction linac

International Nuclear Information System (INIS)

Ding, B.N.; Myers, T.J.; Rhee, M.J.

1992-01-01

Recently, a high-brightness electron beam produced by a simple pseudospark device has been reported. Typically, the electron beam has a peak current of up to 1 kA, FWHM pulse duration of 30 ns, and an effective emittance of 4[ 2 > r2 > - 2] 1/2 = 100 mm-mrad. The normalized brightness of the beam is estimated to be on the order of 10 11 A/(m 2 -rad 2 ). This high-brightness beam may be immediately useful for high current accelerators and free-electron lasers if the beam energy can be boosted up. In this paper, the authors present preliminary results of the post acceleration of the electron beam by using an induction linac. The pseudospark device is modified by adding a trigger electrode in the hollow cavity of the cathode so that the generation of the electron beam is synchronized with the induction linac. A simple induction linac system of 25 kV, 1 kA, 50 ns pulse is being constructed. The electron beam, which is born in a low pressure gas, will be accelerated in the same background gas. This gas provides a sufficient ion channel for necessary focusing of this high-current density beam. Preliminary results on the beam current, energy spectrum, and emittance measurements of the post-accelerated beam will be presented

An induction accelerator for the Heidelberg Test Storage Ring TSR

International Nuclear Information System (INIS)

Ellert, C.; Habs, D.; Music, M.; Schwalm, D.; Wolf, A.; Jaeschke, E.; Kambara, T.; Sigray, P.

1992-01-01

An induction accelerator has been installed in the heavy ion test storage ring TSR in Heidelberg. It allows for constant acceleration or deceleration of stored coasting ion beams without affecting their velocity profile and is well suited for ion beam manipulation in cooling experiments and for measurements of velocity dependent cooling forces. The design and operation of the device and first applications to laser cooling and to measurements of laser and electron cooling forces are described. (orig.)

Preliminary results of Linear Induction Accelerator LIA-200

Energy Technology Data Exchange (ETDEWEB)

Sharma, Archana; Senthil, K; Kumar, D D Praveen; Mitra, S; Sharma, V; Patel, A; Sharma, D K; Rehim, R; Kolge, T S; Saroj, P C; Acharya, S; Amitava, Roy; Rakhee, M; Nagesh, K V; Chakravarthy, D P, E-mail: aroy@barc.gov.i, E-mail: arsharma@barc.gov.i [Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

2010-05-15

Repetitive Pulsed Power Technology is being developed keeping in mind the potential applications of this technology in material modifications, disinfections of water, timber, and food pasteurization etc. BARC has indigenously developed a Linear Induction Accelerator (LIA-200) rated for 200 kV, 4 kA, 100 ns, 10 Hz. The satisfactory performance of all the sub-systems including solid state power modulator, amorphous core based pulsed transformers, magnetic switches, water capacitors, water pulse- forming line, induction adder and field-emission diode have been demonstrated. This paper presents some design details and operational results of this pulsed power system. It also highlights the need for further research and development to build reliable and economic high-average power systems for industrial applications.

Acceleration, current amplification and emittance in MBE-4, an experimental beam induction linear accelerator for heavy ions

International Nuclear Information System (INIS)

Warwick, A.I.; Gough, D.E.; Keefe, D.; Meuth, H.

1988-10-01

We report on the implementation of a second schedule of acceleration and current amplification in MBE-4. Control of the beam current within the bunch is improved over that in the first schedule by the addition of several small amplitude induction pulsers to compensate for acceleration errors and to control the ends of the bunch. Measurements of the longitudinal and transverse emittance are presented. 5 refs., 3 figs., 1 tab

Acceleration units for the Induction Linac Systems Experiment (ILSE)

International Nuclear Information System (INIS)

Faltens, A.; Brady, V.; Brodzik, D.; Hansen, L.; Laslett, L.J.; Mukherjee, S.; Bubp, D.; Ravenscroft, D.; Reginato, L.

1989-03-01

The design of a high current heavy ion induction linac driver for inertial confinement fusion is optimized by adjusting the acceleration units along the length of the accelerator to match the beam current, energy, and pulse duration at any location. At the low energy end of the machine the optimum is a large number of electrostatically focused parallel beamlets, whereas at higher energies the optimum is a smaller number of magnetically focused beams. ILSE parallels this strategy by using 16 electrostatically focused beamlets at the low end followed by 4 magnetically focused beams after beam combining. 3 refs., 2 figs

Development of heavy ion induction linear accelerators as drivers for inertial confinement fusion

International Nuclear Information System (INIS)

Warwick, A.I.; Celata, C.; Faltens, A.; Fessenden, T.J.; Judd, D.L.; Keefe, D.; Kim, C.H.; Laslett, L.J.; Lee, E.P.; Meuth, H.

1988-01-01

This paper reports on a continuing study in the USA of the feasibility of an induction linac fusion driver, which would accelerate multiple heavy-ion beams through a sequence of pulsed transformers and amplify the beam current during acceleration. The driver cost could be $200/Joule or less and the cost of electricity in the range of .050-.055$/kWhr. As a next stage of development to assess the feasibility of this approach the authors propose an Induction Linac Systems Experiment. This will test some of the technology and multiple-beam manipulations necessary for a fusion driver

Development of heavy ion induction linear accelerators as drivers for inertial confinement fusion

International Nuclear Information System (INIS)

Warwick, A.I.; Celata, C.; Faltens, A.

1988-06-01

There is a continuing study in the USA of the feasibility of an induction linac fusion driver, which would accelerate multiple heavy-ion beams through a sequence of pulsed transformers and amplify the beam current during acceleration. The driver cost could be $200/Joule or less and the cost of electricity in the range of .050-.055$/kWhr. As a next stage of development to assess the feasibility of this approach we propose an ''Induction Linac Systems Experiment''. This will test some of the technology and multiple-beam manipulations necessary for a fusion driver. 7 refs., 1 fig

Recirculation of Chilean copper smelting dust with high impurities contents to the smelting process

Energy Technology Data Exchange (ETDEWEB)

Sano, H.; Fujisawa, T. [Nagoya Univ., Nagoya (Japan). EcoTopia Science Inst.; Montenegro, V. [Nagoya Univ., Nagoya (Japan). Dept. of Materials Science and Engineering

2007-07-01

Dust generated during the copper smelting process is generally stabilized using hydrometallurgical methods as it contains high concentrations of arsenic. In this laboratory study, dust was recirculated during the smelting process in order to recover more copper and decrease dust emissions while recovering more copper. The behaviour of impurities and their influence on matte quality was also investigated. Industrial matte, flue dust, slag, and copper concentrates from a Chilean smelter were used as test materials. Dust recirculation tests were conducted in a simulated electric furnace. Off-gases were collected in a reaction tube, and the condensed volatile matter, slag, and matte phases were analyzed for their elemental content by inductively coupled plasma atomic emission spectrometry. The distribution of arsenic (As); antimony (Sb), bismuth (Bi), lead (Pb), and zinc (Zn) were investigated by varying the amounts of dust recirculating to the smelting stage with 21 per cent of the oxygen. Results showed that distributions of all analyzed elements increased with recirculation. It was concluded that copper can be recovered using the dust recirculation technique. However, impurities may limit the efficacy of the dust recirculation process. 6 refs., 3 tabs., 4 figs.

Determination of acceleration and stabilization indicators for buried municipal wastes. Study of leachates recirculation impact on waste columns; Determination d'indicateurs d'acceleration et de stabilisation de dechets menagers enfouis. Etude de l'impact de la recirculation de lixiviats sur colonnes de dechets

Energy Technology Data Exchange (ETDEWEB)

Francois, V.

2004-05-15

The main goal of this research work was to study the stabilisation processes of municipal solid waste (MSW). Representative parameters, which are required to evaluate the stabilization state of wastes, were applied to study the acceleration of the degradation processes in lab-scale landfill anaerobic bioreactors operated with leachate recirculation. The characterisation of the wastes solid phase (i.e., volatile solids, organic carbon, fines, paper-cardboard and degraded component contents) is necessary to assess its degradation state. However, additional parameters are required such as the characterisation of water extracted from the waste (i.e., Chemical Oxygen Content (COD), Dissolved Oxygen Content (DOC) and ions content) and biogas composition (methane potential). Those parameters are nevertheless complementary to conclude on its polluting feature. The analysis of more specific indicators such as the organic macromolecules content in leachates and the evaluation of the metal contamination level in solid waste and its potential remobilization was showed to be consistent for the evaluation of waste stabilisation state. The composition of leachates used during recirculation influences greatly the waste leaching behaviour. For instance, the recirculation of a stabilised leachate containing organic macromolecules can increase the release of pollutants (organics and minerals) if contacted with young waste or on the other hand the release of pollutant is reduced when the leachate composition is similar to the organic species, which are expected to be released by the wastes. Due to the experimental limits of the leaching tests, several lab-scale landfill anaerobic bioreactors containing different wastes types (height of 1 m and mass of waste varying from 28 kg to 65 kg) were operated to study the effects of recirculation on the waste degradation at flow rate of 540 mL per day. The speed-up of waste degradation was clearly established from global parameters measured on

Induction linacs

International Nuclear Information System (INIS)

Keefe, D.

1986-07-01

The principle of linear induction acceleration is described, and examples are given of practical configurations for induction linacs. These examples include the Advanced Technology Accelerator, Long Pulse Induction Linac, Radial Line Accelerator (RADLAC), and Magnetically-Insulated Electron-Focussed Ion Linac. A related concept, the auto accelerator, is described in which the high-current electron-beam technology in the sub-10 MeV region is exploited to produce electron beams at energies perhaps as high as the 100 to 1000 MeV range. Induction linacs for ions are also discussed. The efficiency of induction linear acceleration is analyzed

A new linear inductive voltage adder driver for the Saturn Accelerator

International Nuclear Information System (INIS)

Mazarakis, M.G.; Spielman, R.B.; Struve, K.W.; Long, F.W.

2000-01-01

Saturn is a dual-purpose accelerator. It can be operated as a large-area flash x-ray source for simulation testing or as a Z-pinch driver especially for K-line x-ray production. In the first mode, the accelerator is fitted with three concentric-ring 2-MV electron diodes, while in the Z-pinch mode the current of all the modules is combined via a post-hole convolute arrangement and driven through a cylindrical array of very fine wires. We present here a point design for a new Saturn class driver based on a number of linear inductive voltage adders connected in parallel. A technology recently implemented at the Institute of High Current Electronics in Tomsk (Russia) is being utilized. In the present design we eliminate Marx generators and pulse-forming networks. Each inductive voltage adder cavity is directly fed by a number of fast 100-kV small-size capacitors arranged in a circular array around each accelerating gap. The number of capacitors connected in parallel to each cavity defines the total maximum current. By selecting low inductance switches, voltage pulses as short as 30-50-ns FWHM can be directly achieved. The voltage of each stage is low (100-200 kv). Many stages are required to achieve multi-megavolt accelerator output. However, since the length of each stage is very short (4-10 cm), accelerating gradients of higher than 1 MV/m can easily be obtained. The proposed new driver will be capable of delivering pulses of 15-MA, 36-TW, 1.2-MJ to the diode load, with a peak voltage of -2.2 MV and FWHM of 40-ns. And although its performance will exceed the presently utilized driver, its size and cost could be much smaller (approximately1/3). In addition, no liquid dielectrics like oil or deionized water will be required. Even elimination of ferromagnetic material (by using air-core cavities) is a possibility

Acceleration, current amplification and emittance in MBE-4, an experimental multiple beam induction linear accelerator for heavy ions

International Nuclear Information System (INIS)

Warwick, A.I.; Gough, D.E.; Keefe, D.; Meuth, H.

1989-01-01

The authors report on the implementation of a second schedule of acceleration and current amplification in MBE-4. Control of the beam current within the bunch is improved over that in the first schedule by the addition of several small amplitude induction pulsers to compensate for acceleration errors and to control the ends of the bunch. Measurements of the longitudinal and transverse emittance are presented. 5 refs., 3 figs., 1 tab

Mineral and organic compounds in leachate from landfill with concentrate recirculation.

Science.gov (United States)

Talalaj, Izabela Anna

2015-02-01

The effect of a reverse osmosis concentrate recirculation on the mineral and organic compounds in a landfill leachate was investigated. Investigated was the quality of a leachate from two landfills operated for different periods (a 20-year-old Cell A and a 1-year-old Cell B), where the concentrate was recirculated. Examined were general parameters (conductivity, pH), organic compounds (biochemical oxygen demand (BOD), chemical oxygen demand (COD), total organic nitrogen, BOD/COD), and inorganic compounds (nitrogen ammonia, sulfite, sulfate, cyanide, boron, chloride, ferrous, zinc, chrome, copper). The findings from the first year of investigation showed that over the initial period of recirculation, the concentration of organic compounds (BOD, COD) increased, but after 6 months their values stabilized. It indicates that the concentrate recirculation accelerated organic decomposition, especially in the new landfill Cell. The analysis of inorganic parameters showed that recirculation landfills produce a leachate with a higher concentration of N-NH4, and Cl(-). In case of the old landfill Cell, an increase in B and Fe was also noticeable. These compounds are cyclically washed out from a waste dump and require an additional pretreatment in order to exclude them from recirculation cycle. The increased concentration of Cu, Zn, and Fe was noticed during the initial months of recirculation and in the season of intense atmospheric precipitation in the leachate from both Cells. Higher values of electro conductivity, Cl(-), N-NH4 (+), B, and Fe in the leachate from the old field indicate that the attenuation capacity of this landfill is close to exhaustion.

Longitudinal and radial MHD linear induction accelerator with hot conducting plasma core

International Nuclear Information System (INIS)

Denno, K.

1985-01-01

Conceptual design of linear induction accelerator is presented using for the core continuum a highly conductive plasma with sustained pumping velocity. Karlovitz criterion of boundary theory is employed in the process of design

Inductive and electrostatic acceleration in relativistic jet-plasma interactions.

Science.gov (United States)

Ng, Johnny S T; Noble, Robert J

2006-03-24

We report on the observation of rapid particle acceleration in numerical simulations of relativistic jet-plasma interactions and discuss the underlying mechanisms. The dynamics of a charge-neutral, narrow, electron-positron jet propagating through an unmagnetized electron-ion plasma was investigated using a three-dimensional, electromagnetic, particle-in-cell computer code. The interaction excited magnetic filamentation as well as electrostatic plasma instabilities. In some cases, the longitudinal electric fields generated inductively and electrostatically reached the cold plasma-wave-breaking limit, and the longitudinal momentum of about half the positrons increased by 50% with a maximum gain exceeding a factor of 2 during the simulation period. Particle acceleration via these mechanisms occurred when the criteria for Weibel instability were satisfied.

Experimental research on electromagnetic radiation in inductive energy storage accelerator

International Nuclear Information System (INIS)

Zhong Jianzhong; Liu Lie; Li Limin; Wen Jianchun

2008-01-01

There exists strong electromagnetic radiation in inductive energy storage accelerators. In can destroy a measuring device at a distance. By repeated experiments, we found that it is a wide-spectrum electromagnetic wave with a main frequency of 75 MHz. The effector such as coaxial transmission line is effected strongly in short distance. The current in the coaxial transmission line can be measured in Rogowski coils. The strength of field in it is about 500 V/m and the peak current is 217 mA. The radiation source may be LC oscillating or electric exploding opening switch. Through the experimental research, we think it probably may be caused by the LC oscillating in the circuit when the switches conduct. And its strength is correlated to current change ratio. The change rate in secondary circuit is stronger than in primary circuit. So the radiation generated in secondary circuit is stronger than in primary circuit. It may be a reference for further research in inductive energy storage accelerators and shielding electromagnetic disturbing. (authors)

Two-phase flow phenomena in broken recirculation line of BWR

International Nuclear Information System (INIS)

Kato, Masami; Arai, Kenji; Narabayashi, Tadashi; Amano, Osamu.

1986-01-01

When a primary recirculation line of BWR is ruptured, a primary recirculation pump may be subjected to very high velocity two-phase flow and its speed may be accelerated by this flow. It is important for safety evaluation to estimate the pump behavior during blowdown. There are two problems involved in analyzing this behavior. One problem concerns the pump characteristics under two-phase flow. The other involves the two-phase conditions at the pump inlet. If the rupture occurs at a suction side of the pump, choking is considered to occur at a broken jet pump nozzle. Then, a void fraction becomes larger downstream from the jet pump nozzle and volumetric flow through the pump will be very high. However, there is little experimental data available on two-phase flow downstream from a choking plane. Blowdown tests were performed using a simulated broken recirculation line and measured data were analyzed by TRAC-PlA. Analytical results agreed with measured data. (author)

Multipurpose 5-MeV linear induction accelerator

International Nuclear Information System (INIS)

Birx, D.L.; Hawkins, S.A.; Poor, S.E.; Reginato, L.L.; Smith, M.W.

1984-01-01

Although linear induction accelerators (LIAs) are quite reliable by most standards, they are limited in repeating rate, average power, and reliability because the final stage of energy delivery is based on spark gap performance. In addition, they have a low duty factor of operation. To provide a higher burst rate and greater reliability, the researchers used new technology to develop a magnetic pulse compression scheme that eliminates all spark gaps and exceeds requirements. The paper describes the scheme. The magnetic drive system can be tailored to drive induction cells from a few kA to over 10 kA at 500 kV, with average beam power levels in the megawatts. This new 5-MeV, 2.5-kA LIA under construction at the Lawrence Livermore National Laboratory (LLNL) will be used for the development of high brightness sources and will provide a test bed for the new technology, which should lead to LIAs that surpass the radio frequency linacs for efficiency and reliability, as well as fit other industrial applications, such as sewage sterilization

Engineering research and development for the Elise Heavy Ion Induction Accelerator

International Nuclear Information System (INIS)

Reginato, L.; Peters, C.

1995-08-01

The Fusion Energy Research engineering team has been conducting Research and Development Associated with the Construction (RDAC) of the Elise accelerator since the approval of Key Decision one (KD1 is start of construction). The engineering design effort has worked in close cooperation with the physics design staff to achieve all parameters of the Elise accelerator. The design included the 2 MV injector, matching section, combiner, induction cells, electric/magnetic quadrupoles, alignment system and controls. All major designs and some hardware testing will be discussed

Engineering research and development for the Elise heavy ion induction accelerator

International Nuclear Information System (INIS)

Reginato, L.; Peters, C.

1996-01-01

The fusion energy research engineering team has been conducting research and development associated with the construction of the Elise accelerator since the approval of key decision 1 (this is the start of construction). The engineering design effort has worked in close cooperation with the physics design staff to achieve all parameters of the Elise accelerator. The design included the 2 MV injector, matching section, combiner, induction cells, electric-magnetic quadrupoles, alignment system and controls. All major designs and some hardware testing will be discussed. (orig.)

Magnetic field alignment for a 20 MeV linear induction accelerator

International Nuclear Information System (INIS)

Zhang Wenwei; Pan Haifeng; Li Hong; Liu Yunlong; Zhang Linwen

2002-01-01

'Dragon-1' accelerator now is being constructed in CAEP. It will produce high current pulse electron beams. The main components of the accelerator include 72 induction accelerating cells and 18 connection cells with ports for beam di gnostic hardware and vacuum pump. In order to acquire high quality beams, a lot of problems have to be addressed such as to reduce the emittance, to control the increase of corkscrew and so on. The alignment of the focus magnetic field is the most concerned. A laser track has been used for mechanical alignment, magnetic alignment is performed by using pulsed-wire technique, and the natural tilt errors is corrected by a pair of steering coil, which is located inside the cell

Racetrack linear accelerators

International Nuclear Information System (INIS)

Rowe, C.H.; Wilton, M.S. de.

1979-01-01

An improved recirculating electron beam linear accelerator of the racetrack type is described. The system comprises a beam path of four straight legs with four Pretzel bending magnets at the end of each leg to direct the beam into the next leg of the beam path. At least one of the beam path legs includes a linear accelerator. (UK)

Method for the mechanical axis alignment of the linear induction accelerator

International Nuclear Information System (INIS)

Li Hong; China Academy of Engineering Physics, Mianyang; Yao Jin; Liu Yunlong; Zhang Linwen; Deng Jianjun

2004-01-01

Accurate mechanical axis alignment is a basic requirement for assembling a linear induction accelerator (LIA). The total length of an LIA is usually over thirty or fifty meters, and it consists of many induction cells. By using a laser tracker a new method of mechanical axis alignment for LIA is established to achieve the high accuracy. This paper introduces the method and gives implementation step and point position measure errors of the mechanical axis alignment. During the alignment process a 55 m-long alignment control survey net is built, and the theoretic revision of the coordinate of the control survey net is presented. (authors)

Engineering method of calculation and choice of main parameters of the linear induction accelerator inductors

Directory of Open Access Journals (Sweden)

В.Т. Чемерис

2006-04-01

Full Text Available  There is a method of simplified calculation and design parameters choice elaborated in this article with corresponding basing for the induction system of electron-beam sterilizer on the base of linear induction accelerator taking into account the parameters of magnetic material for production of cores and parameters of pulsed voltage.

Recirculation system for nuclear reactors

International Nuclear Information System (INIS)

Braun, H. E.; Dollard, W. J.; Tower, S. N.

1980-01-01

A recirculation system for use in pressurized water nuclear reactors to increase the output temperature of the reactor coolant, thereby achieving a significant improvement in plant efficiency without exceeding current core design limits. A portion of the hot outlet coolant is recirculated to the inlets of the peripheral fuel assemblies which operate at relatively low power levels. The outlet temperature from these peripheral fuel assemblies is increased to a temperature above that of the average core outlet. The recirculation system uses external pumps and introduces the hot recirculation coolant to the free space between the core barrel and the core baffle, where it flows downward and inward to the inlets of the peripheral fuel assemblies. In the unlikely event of a loss of coolant accident, the recirculation system flow path through the free space and to the inlets of the fuel assemblies is utilized for the injection of emergency coolant to the lower vessel and core. During emergency coolant injection, the emergency coolant is prevented from bypassing the core through the recirculation system by check valves inserted into the recirculation system piping

Improved focus solenoid design for linear induction accelerators

International Nuclear Information System (INIS)

Zentler, J.M.; Van Maren, R.D.; Nexsen, W.E.

1992-08-01

Our FXR linear induction accelerator produces a 2 KA, 17 MeV electron beam of 60 ns duration. The beam is focused on a tantalum target to produce x-rays for radiography. The FWHM spot size of the focused beam is currently 2.2 mm. We strive to reduce the spot size by 30% by improving the field characteristics of focusing solenoids housed in each of 50 induction cells along the beamline. Tilts in the magnetic axis of the existing solenoids range up to 12 mrad (0.7 degrees). We are building new solenoid assemblies which include ferromagnetic homogenizer rings. These dramatically reduce field errors. A field tilt of under 0.5 mrad has been achieved. Mechanical alignment of the rings is critical. We developed a novel construction method in which the rings are wound with 4 mil thick Si-Fe ribbon into grooves on an aluminum cylinder. The cylinder then becomes the winding mandrel for the focus solenoids. This forms a more accurate and compact assembly than the standard practice of pressing individual solid rings onto a tube

Induction Accelerator Technology Choices for the Integrated Beam Experiment (IBX)

International Nuclear Information System (INIS)

Leitner, M.A.; Celata, C.M.; Lee, E.P.; Logan, B.G.; Sabbi, G.; Waldron, W.L.; Barnard, J.J.

2003-01-01

Over the next three years the research program of the Heavy Ion Fusion Virtual National Laboratory (HIF-VNL), a collaboration among LBNL, LLNL, and PPPL, is focused on separate scientific experiments in the injection, transport and focusing of intense heavy ion beams at currents from 100 mA to 1 A. As a next major step in the HIF-VNL program, we aim for a complete 'source-to-target' experiment, the Integrated Beam Experiment (IBX). By combining the experience gained in the current separate beam experiments IBX would allow the integrated scientific study of the evolution of a single heavy ion beam at high current (∼1 A) through all sections of a possible heavy ion fusion accelerator: the injection, acceleration, compression, and beam focusing.This paper describes the main parameters and technology choices of the planned IBX experiment. IBX will accelerate singly charged potassium or argon ion beams up to 10 MeV final energy and a longitudinal beam compression ratio of 10, resulting in a beam current at target of more than 10 Amperes. Different accelerator cell design options are described in detail: Induction cores incorporating either room temperature pulsed focusing-magnets or superconducting magnets

Hybrid preheat/recirculating steam generator

International Nuclear Information System (INIS)

Lilly, G.P.

1985-01-01

The patent describes a hybrid preheat/recirculating steam generator for nuclear power plants. The steam generator utilizes recirculated liquid to preheat incoming liquid. In addition, the steam generator incorporates a divider so as to limit the amount of recirculating water mixed with the feedwater. (U.K.)

The light ion pulsed power induction accelerator for ETF

International Nuclear Information System (INIS)

Mazarakis, M.G.; Olson, R.E.; Olson, C.L.; Smith, D.L.; Bennett, L.F.

1994-01-01

Our Engineering Test Facility (ETF) driver concept is based on HERMES III and RHEPP technologies. Actually, it is a scaled-down version of the LMF design incorporating repetition rate capabilities of up to 10 Hz CW. The preconceptual design presented here provides 200-TW peak power to the ETF target during 10 ns, equal to 2-MJ total ion beam energy. Linear inductive voltage addition driving a self-magnetically insulated transmission line (MITL) is utilized to generate the 36-MV peak voltage needed for lithium ion beams. The ∼ 3-MA ion current is achieved by utilizing many accelerating modules in parallel. Since the current per module is relatively modest (∼300 kA), two-stage or one-stage extraction diodes can be utilized for the generation of singly charged lithium ions. The accelerating modules are arranged symmetrically around the fusion chamber in order to provide uniform irradiation onto the ETF target. In addition, the modules are fired in a programmed sequence in order to generate the optimum power pulse shape onto the target. This design utilizes RHEPP accelerator modules as the principal power source

CFD modeling of hydro-biochemical behavior of MSW subjected to leachate recirculation.

Science.gov (United States)

Feng, Shi-Jin; Cao, Ben-Yi; Li, An-Zheng; Chen, Hong-Xin; Zheng, Qi-Teng

2018-02-01

The most commonly used method of operating landfills more sustainably is to promote rapid biodegradation and stabilization of municipal solid waste (MSW) by leachate recirculation. The present study is an application of computational fluid dynamics (CFD) to the 3D modeling of leachate recirculation in bioreactor landfills using vertical wells. The objective is to model and investigate the hydrodynamic and biochemical behavior of MSW subject to leachate recirculation. The results indicate that the maximum recirculated leachate volume can be reached when vertical wells are set at the upper middle part of a landfill (H W /H T  = 0.4), and increasing the screen length can be more helpful in enlarging the influence radius than increasing the well length (an increase in H S /H W from 0.4 to 0.6 results in an increase in influence radius from 6.5 to 7.7 m). The time to reach steady state of leachate recirculation decreases with the increase in pressure head; however, the time for leachate to drain away increases with the increase in pressure head. It also showed that methanogenic biomass inoculum of 1.0 kg/m 3 can accelerate the volatile fatty acid depletion and increase the peak depletion rate to 2.7 × 10 -6  kg/m 3 /s. The degradation-induced void change parameter exerts an influence on the processes of MSW biodegradation because a smaller parameter value results in a greater increase in void space.

Optimization of the linear induction accelerator construction for maximizing the bremsstrahlung output

Energy Technology Data Exchange (ETDEWEB)

Zinchenko, V F; Tulisov, E V; Chlenov, A M; Shiyan, V D [Research Institute of Scientific Instruments, Turaevo-Lytkarino (Russian Federation)

1997-12-31

The results of experimental and theoretical optimization of the linear induction accelerator (LIA) design are presented. The major aim of the investigations was to maximize the bremsstrahlung output near the target face. The work was carried out in two stages: l) modernization of the injector module and 2) focusing of the relativistic electron beam (REB) produced at the exit of the accelerating system (AS) in the increasing axial magnetic field. In addition, the methods of diagnostics of angular and energetic parameters of REB based on measurements of radiation dose fields behind the target are described. (author). 2 figs., 4 refs.

Mechanical design of the recirculating, terminal pumping in the Lund Pelletron, and experimental experience

International Nuclear Information System (INIS)

Hellborg, R.; Hakansson, K.; Faarinen, M.; Kiisk, M.; Persson, P.; Skog, G.; Stenstroem, K.

2002-01-01

A recirculating terminal pumping system has been installed in the 3 MV Pelletron tandem accelerator in Lund. An extremely limited space in the high voltage terminal and the absence of electrical power in the terminal, forced us to provide a unique design for the installation and powering of the new pumps. Details of the technical design, as well as experience of the use of the new system for accelerator mass spectrometry, will be given. (author)

High ratio recirculating gas compressor

Science.gov (United States)

Weinbrecht, J.F.

1989-08-22

A high ratio positive displacement recirculating rotary compressor is disclosed. The compressor includes an integral heat exchanger and recirculation conduits for returning cooled, high pressure discharge gas to the compressor housing to reducing heating of the compressor and enable higher pressure ratios to be sustained. The compressor features a recirculation system which results in continuous and uninterrupted flow of recirculation gas to the compressor with no direct leakage to either the discharge port or the intake port of the compressor, resulting in a capability of higher sustained pressure ratios without overheating of the compressor. 10 figs.

Induction linear accelerators for commercial photon irradiation processing

International Nuclear Information System (INIS)

Matthews, S.M.

1989-01-01

A number of proposed irradiation processes requires bulk rather than surface exposure with intense applications of ionizing radiation. Typical examples are irradiation of food packaged into pallet size containers, processing of sewer sludge for recycling as landfill and fertilizer, sterilization of prepackaged medical disposals, treatment of municipal water supplies for pathogen reduction, etc. Volumetric processing of dense, bulky products with ionizing radiation requires high energy photon sources because electrons are not penetrating enough to provide uniform bulk dose deposition in thick, dense samples. Induction Linear Accelerator (ILA) technology developed at the Lawrence Livermore National Laboratory promises to play a key role in providing solutions to this problem. This is discussed in this paper

Electron beam dynamics in the long-pulse, high-current DARHT-II linear induction accelerator

International Nuclear Information System (INIS)

Ekdahl, Carl A.; Abeyta, Epifanio O.; Aragon, Paul; Archuleta, Rita; Cook, Gerald; Dalmas, Dale; Esquibel, Kevin; Gallegos, Robert A.; Garnett, Robert; Harrison, James F.; Johnson, Jeffrey B.; Jacquez, Edward B.; Mccuistian, Brian T.; Montoya, Nicholas A.; Nath, Subrato; Nielsen, Kurt; Oro, David; Prichard, Benjamin; Rowton, Lawrence; Sanchez, Manolito; Scarpetti, Raymond; Schauer, Martin M.; Seitz, Gerald; Schulze, Martin; Bender, Howard A.; Broste, William B.; Carlson, Carl A.; Frayer, Daniel K.; Johnson, Douglas E.; Tom, C.Y.; Williams, John; Hughes, Thomas; Anaya, Richard; Caporaso, George; Chambers, Frank; Chen, Yu-Jiuan; Falabella, Steve; Guethlein, Gary; Raymond, Brett; Richardson, Roger; Trainham, C.; Watson, Jim; Weir, John; Genoni, Thomas; Toma, Carsten

2009-01-01

The DARHT-II linear induction accelerator (LIA) now accelerates 2-kA electron beams to more than 17 MeV. This LIA is unique in that the accelerated current pulse width is greater than 2 microseconds. This pulse has a flat-top region where the final electron kinetic energy varies by less than 1% for more than 1.5 microseconds. The long risetime of the 6-cell injector current pulse is 0.5 (micro)s, which can be scraped off in a beam-head cleanup zone before entering the 68-cell main accelerator. We discuss our experience with tuning this novel accelerator; and present data for the resulting beam transport and dynamics. We also present beam stability data, and relate these to previous stability experiments at lower current and energy.

Operation of LIA-30 linear induction accelerator in the mode of generation of two bremsstrahlung pulses

Energy Technology Data Exchange (ETDEWEB)

Bossamykin, V S; Gerasimov, A I; Gordeev, V S; Grishin, A V; Gritsina, V P; Tarasov, A D; Fedotkin, A S; Lazarev, S A; Averchenkov, A Ya [All-Russian Scientific Research Institute of Experimental Physics, Sarov (Russian Federation)

1997-12-31

The operating mode was studied of the LIA-30 linear induction accelerator ({approx} 40 MeV, {approx} 100 kA, {approx} 30 ns) with the generation of two bremsstrahlung pulses separated by a specified time interval from 0 to 5 {mu}s. In the accelerating channel an additional tube cathode was installed, and a synchronization system for two accelerating module groups triggering the formation and acceleration, at different initial times, of two annular electron beams with different outer diameters was changed. The energy limit of each beam electron acceleration can be controlled, and the energy sum limit is {<=} 540 MeV. (author). 2 tabs., 2 figs.

Suppressing beam-centroid motion in a long-pulse linear induction accelerator

Directory of Open Access Journals (Sweden)

Carl Ekdahl

2011-12-01

Full Text Available The second axis of the dual-axis radiography of hydrodynamic testing (DARHT facility produces up to four radiographs within an interval of 1.6  μs. It does this by slicing four micropulses out of a 2-μs long electron beam pulse and focusing them onto a bremsstrahlung converter target. The 1.8-kA beam pulse is created by a dispenser cathode diode and accelerated to more than 16 MeV by the unique DARHT Axis-II linear induction accelerator (LIA. Beam motion in the accelerator would be a problem for multipulse flash radiography. High-frequency motion, such as from beam-breakup (BBU instability, would blur the individual spots. Low-frequency motion, such as produced by pulsed-power variation, would produce spot-to-spot differences. In this article, we describe these sources of beam motion, and the measures we have taken to minimize it. Using the methods discussed, we have reduced beam motion at the accelerator exit to less than 2% of the beam envelope radius for the high-frequency BBU, and less than 1/3 of the envelope radius for the low-frequency sweep.

Bidirectional pulser made from pulse lines for linear induction accelerators

International Nuclear Information System (INIS)

Hotta, E.; Mori, T.; Kobayashi, T.; Okino, A.; Haginomori, E.; Ko, K.C.

1996-01-01

In order to obtain high-current charged particle beams, linear induction accelerators (LIA's) of two types have been already constructed. Conventional LIA's adopt a unidirectional pulse injected from an external pulser. The other LIA's, one of which has been proposed and constructed by Pavlovskii et al., have accelerating cavities made from pulse forming lines (PFL's). In this case, no magnetic core loaded in the cavity is necessary. However, the injected pulse must be a bidirectional one. Since a part of the voltage pulse with reversed polarity is used to accelerate a beam, it is possible to make the time integral of the output voltage zero. Thus the final magnetic energy stored in the cavity can be made zero at the end of the pulse, and the pulser-accelerator system attains the energy transfer efficiency of 100%. Accelerators of this type can be divided into two kinds, one of which has cavities with internal energy storage, and the other has cavities with energy injected from external bidirectional pulsers. The accelerator of latter type has been first proposed by Smith, but it has not been realized. Several bidirectional pulsers, which consist of three individual PFL's with arbitrary impedances and a closing switch, are analyzed. Output voltages are analytically calculated by using the method proposed by Dommel for digital computations of electromagnetic transients in networks, and conditions for attaining the maximum efficiency of energy transfer from the pulser to the beam are derived. Thus, 4 bidirectional pulsers of internal energy storage type and 2 of external pulse injection type with energy transfer efficiency of 100% are obtained, including the pulsers already reported by other authors

Voltage-regulating constant-current sources in a linear induction accelerator

International Nuclear Information System (INIS)

Zhao Juan; Cao Kefeng; Deng Jianjun; Zhu Lijun; Yang Jia; Ye Chao; Huang Bin; Cao Ningxiang; Dong Jinxuan; Zhang Jichang; Yu Zhiguo; Chen Min

2002-01-01

Constant-current Sources are one of key units in a linear induction accelerator. The requirements for the sources are to supply stable direct current of high power for the induction coil, be easy to computer-control and highly stable and reliable. Applying the technique of linear current source regulating in series, the primary voltage of the power transformer is regulated through an MJYS-JL-350A type three-phase alterative voltage-regulating module. The output current variation is 300-500 A when the load variation is 0.06-0.1 Ω and the voltage drop of the regulator tube is controlled within 8 V±2V when the variation of mains voltage is in ±10%. Both the current ripple and stability meet the technical requirements. The constant-current sources are controlled through an industrial controller. For each of the constant-current sources has a smallest system comprised of 8051 which is communication-controlled through a RS-485 interface, the sources can be controlled remotely

A new gas stripper system for BARC-TIFR Pelletron Accelerator facility: installation and preliminary results

International Nuclear Information System (INIS)

Sharma, S.C.; Ninawe, N.G.; Yadav, M.L.; Ekambaram, M.; Ramjilal; Matkar, U.V.; Ansari, Q.N.; Lokare, R.N.; Ramlal; Gupta, A.K.; Bhagwat, P.V.; Pillay, R.G.

2009-01-01

The gas-stripper plays a key role in stripping the heavy and molecular ion beams in a tandem accelerator. Efficiency of gas stripper depends on its supporting vacuum pumps. A new recirculating turbo molecular pump-based gas stripper has been installed in the high voltage terminal of Pelletron Accelerator. Re-circulating the stripper gas reduces the flow of gas into the accelerating tubes reducing the transmission losses. Preliminary results obtained using the new gas stripper system are discussed. (author)

Recirculating beam-breakup thresholds for polarized higher-order modes with optical coupling

Directory of Open Access Journals (Sweden)

Georg H. Hoffstaetter

2007-04-01

Full Text Available Here we will derive the general theory of the beam-breakup (BBU instability in recirculating linear accelerators with coupled beam optics and with polarized higher-order dipole modes. The bunches do not have to be at the same radio-frequency phase during each recirculation turn. This is important for the description of energy recovery linacs (ERLs where beam currents become very large and coupled optics are used on purpose to increase the threshold current. This theory can be used for the analysis of phase errors of recirculated bunches, and of errors in the optical coupling arrangement. It is shown how the threshold current for a given linac can be computed and a remarkable agreement with tracking data is demonstrated. General formulas are then analyzed for several analytically solvable problems: (a Why can different higher order modes (HOM in one cavity couple and why can they then not be considered individually, even when their frequencies are separated by much more than the resonance widths of the HOMs? For the Cornell ERL as an example, it is noted that optimum advantage is taken of coupled optics when the cavities are designed with an x-y HOM frequency splitting of above 50 MHz. The simulated threshold current is then far above the design current of this accelerator. To justify that the simulation can represent an actual accelerator, we simulate cavities with 1 to 8 modes and show that using a limited number of modes is reasonable. (b How does the x-y coupling in the particle optics determine when modes can be considered separately? (c How much of an increase in threshold current can be obtained by coupled optics and why does the threshold current for polarized modes diminish roughly with the square root of the HOMs’ quality factors. Because of this square root scaling, polarized modes with coupled optics increase the threshold current more effectively for cavities that have rather large HOM quality factors, e.g. those without very

Human skin is protected by four functionally and phenotypically discrete populations of resident and recirculating memory T cells

Science.gov (United States)

Watanabe, Rei; Gehad, Ahmed; Yang, Chao; Campbell, Laura; Teague, Jessica E.; Schlapbach, Christoph; Elco, Christopher; Huang, Victor; Matos, Tiago R.; Kupper, Thomas S.; Clark, Rachael A.

2015-01-01

The skin of an adult human contains approximately 20 billion memory T cells. Epithelial barrier tissues are infiltrated by a combination of resident and recirculating T cells in mice but the relative proportions and functional activities of resident versus recirculating T cells have not been evaluated in human skin. We discriminated resident from recirculating T cells in human engrafted mice and lymphoma patients using alemtuzumab, a medication that depletes recirculating T cells from skin, and then analyzed these T cell populations in healthy human skin. All non-recirculating resident memory T cells (TRM) expressed CD69, but the majority were CD4+, CD103− and located in the dermis, in contrast to studies in mice. Both CD4+ and CD8+ CD103+ TRM were enriched in the epidermis, had potent effector functions and had a limited proliferative capacity compared to CD103− TRM. TRM of both types had more potent effector functions than recirculating T cells. Induction of CD103 on human T cells was enhanced by keratinocyte contact, depended on TGFβ and was independent of T cell keratinocyte adhesive interactions. We observed two distinct populations of recirculating T cells, CCR7+/L-selectin+ central memory T cells (TCM) and CCR7+/L-selectin− T cells, which we term migratory memory T cells (TMM). Circulating skin-tropic TMM were intermediate in cytokine production between TCM and effector memory T cells. In patients with cutaneous T cell lymphoma, malignant TCM and TMM induced distinct inflammatory skin lesions and TMM were depleted more slowly from skin after alemtuzumab, suggesting TMM may recirculate more slowly. In summary, human skin is protected by four functionally distinct populations of T cells, two resident and two recirculating, with differing territories of migration and distinct functional activities. PMID:25787765

The CEBAF [Continuous Electron Beam Accelerator Facility] superconducting accelerator: An overview

International Nuclear Information System (INIS)

Leemann, C.W.

1986-01-01

The CEBAF accelerator is a CW linac based on rf superconductivity and making use of multiple recirculation. Its major components are a 50 MeV injector, two linac segments of 0.5 GeV energy gain each, and recirculator arcs connecting the two linac segments. Each linac segment consists of 25 cryomodules, separated by warm sections with quadrupoles, steering magnets, and beam diagnostics. Each cryomodule contains 8, 1500 MHz, 5-cell, Cornell type cavities with waveguide couplers for fundamental power and HOM damping, each cavity being powered by its own klystron. Recirculator arcs are vertically stacked, large radius, strong focusing beam lines that minimize synchrotron radiation effects. A high quality (ΔE/E ∼ 10 -4 , ε ∼ 10 -9 m) beam of 200μA, 100% duty factor, with 0.5 GeV ≤ E ≤ 4.0 GeV will be generated

Advanced test accelerator (ATA), a 50 MeV, 10 kA induction linac

International Nuclear Information System (INIS)

Reginato, L.

1983-01-01

The ATA is an induction accelerator designed to produce 70 ns pulses of electrons at currents of 10 kA and energies in excess of 50 MeV. The accelerator is capable of operating at an average rate of 5 Hz or at 1 kHz for ten pulses. The parameters were chosen primarily to provide the experimental basis for advancing the understanding of electron beam propagation physics. The 85 m accelerator has been under construction for the past four years and has adopted mainly an improved version of the ETA technology to satisfy the required parameters. Initial operation of the facility and the energy conversion system from primary power to axial electric field will be described; recent advances in magnetic switching which have been incorporated in the innector will also be discussed

Electron beam potential measurements on an inductive-store, opening-switch accelerator

International Nuclear Information System (INIS)

Riordan, J.C.; Goyer, J.R.; Kortbawi, D.; Meachum, J.S.; Mendenhall, R.S.; Roth, I.S.

1993-01-01

Direct measurement of the accelerating potential in a relativistic electron beam accelerator is difficult, particularly when the diode is downstream from a plasma opening switch. An indirect potential measurement can be obtained from the high energy tail of the bremsstrahlung spectrum generated as the electron beam strikes the anode. The authors' time-resolved spectrometer contains 7 silicon pin diode detectors filtered with 2 to 15 mm of lead to span an electron energy range of 0.5 to 2 MeV. A Monte-Carlo transport code was used to provide calibration curves, and the resulting potential measurements have been confirmed in experiments on the PITHON accelerator. The spectrometer has recently been deployed on PM1, an inductive-store, opening-switch testbed. The diode voltage measurements from the spectrometer are in good agreement with the diode voltage measured upstream and corrected using transmission line relations. The x-ray signal and spectral voltage rise 10 ns later than the corrected electrical voltage, however, indicating plasma motion between the opening switch and the diode

Accelerating complex for basic researches in the nuclear physics

NARCIS (Netherlands)

Dovbnya, A.N.; Guk, I.S.; Kononenko, S.G.; Peev, F.A.; Tarasenko, A.S.; Botman, J.I.M.

2009-01-01

In 2003 in NSC KIPT was begun the work on development the project of accelerator, base facility IHEPNP NSC KIPT electron recirculator SALO. The accelerator will be disposed in target hall of accelerator LU 2000 complex. It is projected first of all as facility for basic researches in the field of

Performance of MBE-4: An experimental multiple beam induction linear accelerator for heavy ions

International Nuclear Information System (INIS)

Warwick, A.I.; Fessenden, T.J.; Keefe, D.; Kim, C.H.; Meuth, H.

1988-06-01

An experimental induction linac, called MBE-4, has been constructed to demonstrate acceleration and current amplification of multiple heavy ion beams. This work is part of a program to study the use of such an accelerator as a driver for heavy ion inertial fusion. MBE-4 is 16m long and accelerates four space-charge-dominated beams of singly-charged cesium ions, in this case from 200 keV to 700 keV, amplifying the current in each beam from 10mA by a factor of nine. Construction of the experiment was completed late in 1987 and we present the results of detailed measurements of the longitudinal beam dynamics. Of particular interest is the contribution of acceleration errors to the growth of current fluctuations and to the longitudinal emittance. The effectiveness of the longitudinal focusing, accomplished by means of the controlled time dependence of the accelerating fields, is also discussed. 4 refs., 5 figs., 1 tab

Gun and optics calculations for the Fermilab recirculation experiment

International Nuclear Information System (INIS)

Kroc, T.

1997-10-01

Fermilab is investigating electron cooling to recycle 8 Gev antiprotons recovered from the Tevatron. To do so, it is developing an experiment to recirculate 2 Mev electrons generated by a Pelletron at National Electrostatics Corporation. This paper reports on the optics calculations done in support of that work. We have used the computer codes EGN2 and MacTrace to represent the gun area and acceleration columns respectively. In addition to the results of our simulations, we discuss some of the problems encountered in interfacing the two codes

Failure investigation of stem of valve disc in reactor recirculation system of TAPS Unit-1

International Nuclear Information System (INIS)

Ramadasan, E.; Bahl, J.K.; Sivaramakrishnan, K.S.

1986-01-01

Failure analysis was carried out of failed 17-4 PH stainless steel stem of the valve disc in reactor recirculation system of Unit-1 of Tarapur Atomic Power Station. The examination revealed that the stem failed due to fatigue, accelerated by corrosion. Recommendations have been made to avoid such failures. (author)

Design and performance of a 3.3-MeV linear induction accelerator (LIA)

International Nuclear Information System (INIS)

Cheng Nianan; Zhang Shouyun; Tao Zucong

1992-01-01

A 3.3-MeV linear induction accelerator (LIA) has been designed and constructed at the China Academy of Engineering Physics. The parameters of 3.4 MeV, 2 kA, 80 ns and 1 x 10 4 A/(rad.cm) 2 have been achieved. It has been used for SG-1 FEL experiments. The accelerator is mounted on a movable frame so that , after moving 3 m transversely, it can be assembled with more modules into a 10-MeV LIA. The authors summarize the physics and engineering aspects of the LIA facility and describe the measuring means of characters for the beam

Effect of adding a swirl on flow pattern and recirculation zone in ADS windowless spallation target

Energy Technology Data Exchange (ETDEWEB)

Liu, Jie, E-mail: nauty@ucas.ac.cn [School of Physics, University of Chinese Academy of Sciences, Beijing (China); Gao, Lei [School of Physics, University of Chinese Academy of Sciences, Beijing (China); Yang, Lei [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou (China); Lu, Wen-qiang [School of Physics, University of Chinese Academy of Sciences, Beijing (China)

2014-09-15

Highlights: • The reduction of the recirculation zone and the stability of the free surface are key issues in the target. • A swirl is numerically added in the target to make the recirculation zone small and stable. • Numerical simulation with different boundary conditions is carried out. • Physical analysis is presented to explain the numerical results. - Abstract: Aiming the key issues in the accelerator driven system (ADS), windowless spallation target focus on the minimization of the recirculation zone and on the stability of the free surface, an innovation has been made by numerically adding swirl to the fluid at the inlet. At first, two phase flow pattern in the simulation is compared with the experiments and numerical method is employed correctly. The results reveal that the recirculation zone and the flow pattern are greatly influenced when the swirl strength is changed from 1.0 rad/s to 2.5 rad/s. The height of the recirculation zone decreases with increase in swirl strength and completely disappears when the swirl strength reaches 2.0 rad/s. In addition, larger swirl strength leads to different flow pattern and a new cavitation zone is generated under the recirculation zone. The Bernoulli's equation and angular momentum conservation are applied to make it clear that this phenomena is due to the decrease of the axial pressure caused by the radial velocity. Moreover, the new cavitation zone totally links to the vapor area above the recirculation zone when the swirl strength is 2.5 rad/s. The results are very helpful to the design and optimization of the ADS windowless spallation target.

Effect of adding a swirl on flow pattern and recirculation zone in ADS windowless spallation target

International Nuclear Information System (INIS)

Liu, Jie; Gao, Lei; Yang, Lei; Lu, Wen-qiang

2014-01-01

Highlights: • The reduction of the recirculation zone and the stability of the free surface are key issues in the target. • A swirl is numerically added in the target to make the recirculation zone small and stable. • Numerical simulation with different boundary conditions is carried out. • Physical analysis is presented to explain the numerical results. - Abstract: Aiming the key issues in the accelerator driven system (ADS), windowless spallation target focus on the minimization of the recirculation zone and on the stability of the free surface, an innovation has been made by numerically adding swirl to the fluid at the inlet. At first, two phase flow pattern in the simulation is compared with the experiments and numerical method is employed correctly. The results reveal that the recirculation zone and the flow pattern are greatly influenced when the swirl strength is changed from 1.0 rad/s to 2.5 rad/s. The height of the recirculation zone decreases with increase in swirl strength and completely disappears when the swirl strength reaches 2.0 rad/s. In addition, larger swirl strength leads to different flow pattern and a new cavitation zone is generated under the recirculation zone. The Bernoulli's equation and angular momentum conservation are applied to make it clear that this phenomena is due to the decrease of the axial pressure caused by the radial velocity. Moreover, the new cavitation zone totally links to the vapor area above the recirculation zone when the swirl strength is 2.5 rad/s. The results are very helpful to the design and optimization of the ADS windowless spallation target

Improvement on the accuracy of beam bugs in linear induction accelerator

International Nuclear Information System (INIS)

Xie Yutong; Dai Zhiyong; Han Qing

2002-01-01

In linear induction accelerator the resistive wall monitors known as 'beam bugs' have been used as essential diagnostics of beam current and location. The author presents a new method that can improve the accuracy of these beam bugs used for beam position measurements. With a fine beam simulation set, this method locates the beam position with an accuracy of 0.02 mm and thus can scale the beam bugs very well. Experiment results prove that the precision of beam position measurements can reach submillimeter degree

Accelerator research on MBE-4, an experimental multi-beam induction linac

International Nuclear Information System (INIS)

Meuth, H.; Fessenden, T.J.; Keefe, D.; Warwick, A.I.

1988-06-01

The multiple beam accelerator MBE-4 is a device for research toward a heavy ion driver for inertial confinement fusion, based on the induction linac concept. Its main goal is proof of the principle of current amplification by acceleration and controlled self-similar beam pulse compression. Into the 16-m long device four beams, each with an initial current of 10 mA are injected from a Marx-driven diode at 200 keV. The current amplification is up to nine-fold, with a final beam energy of about 800 keV in the middle of the bunch. Now that all the apparatus' accelerator sections have been completed, installed and aligned, and its unaccelerated transport properties have been studied, our experimental research has reached the crucial phase of implementing appropriate accelerator schedules that approximate self-similar current-pulse compression. These schedules are established through a close interplay of computations using a one-dimensional simulation code and a manual empirical tuning procedure. In a first approach, with a rather vigorous schedule that uses most of the accelerator modules to their voltage limits, we have determined the limits of our capability for controlled pulse compression, mainly due to waveform shaping of the driving pulse-forming networks. We shall report on these results. In the future, we will also aim for gentler schedules that would model more closely an inertial confinement fusion scenario. 8 refs., 11 figs., 1 tab

Fractal solutions of recirculation tubular chemical reactors

International Nuclear Information System (INIS)

Berezowski, Marek

2003-01-01

Three kinds of fractal solutions of model of recirculation non-adiabatic tubular chemical reactors are presented. The first kind concerns the structure of Feigenbaum's diagram on the limit of chaos. The second kind and the third one concern the effect of initial conditions on the dynamic solutions of models. In the course of computations two types of recirculation were considered, viz. the recirculation of mass (return of a part of products' stream) and recirculation of heat (heat exchange in the external heat exchanger)

High-efficiency FEL with Bragg resonator driven by linear induction accelerator

Energy Technology Data Exchange (ETDEWEB)

Ginzburg, N S; Kaminskij, A A; Kaminskij, A K; Peskov, N Yu; Sedykh, S N; Sergeev, A P; Sergeev, A S [Russian Academy of Sciences, Nizhny Novgorod (Russian Federation). Inst. of Applied Physics

1997-12-31

A narrow-band high-efficiency FEL-oscillator with a Bragg resonator was constructed based on a linear induction accelerator which formed a 1 MeV, 200 A, 200 ns electron beam. At the frequency of 31 GHz, radiation with a power of 31 MW and efficiency of 25% was measured. A high efficiency and a narrow width of the spectrum were achieved owing to the selective properties of the Bragg resonator in combination with the high quality of the helical electron beam formed in the reversed guide field regime. (author). 3 figs., 3 refs.

Effect of recirculation rate on methane production and SEBAR system performance using active stage digester.

Science.gov (United States)

Tubtong, Cheevanuch; Towprayoon, Sirintornthep; Connor, Michael Anthony; Chaiprasert, Pawinee; Nopharatana, Annop

2010-09-01

A project was undertaken to examine the feasibility of treating organic wastes from Thai fruit and vegetable markets using the sequential batch anaerobic digester (SEBAR) approach. A key feature of the SEBAR system is the regular interchanging, or recirculation, of portions of leachate between each freshly filled digester and a support digester to which it is coupled until it is ready to operate independently. Leachate transfer from this support digester to the fresh waste digester provides additional alkalinity to help counteract the effects of early high acid release rates; it also helps build a balanced microbial population in the fresh waste digester. To optimize the leachate recirculation process, the effect of varying the quantities of leachate interchanged between freshly filled waste digesters and the still highly active support digesters to which they were coupled was studied. It was found that increasing the recirculation rate accelerated the onset of both waste degradation and methane production. The increasing of recirculation rate from 10% to 20% and 10% to 30% could reduce the SEBAR cycle period by approximately 7% and 22% without significant reduction in the amount of methane obtained from the systems. The methane yields were 0.0063, 0.0068 and 0.0077 l g(-1) VS added in the NEW digester per day using leachate recirculation rates of 10%, 20% and 30%, respectively. This finding has potentially important practical and economic implications for those using the SEBAR system to add value to market waste.

Beam control in the ETA-II linear induction accelerator

International Nuclear Information System (INIS)

Chen, Y.J.

1992-01-01

Corkscrew beam motion is caused by chromatic aberration and misalignment of a focusing system. We have taken some measures to control the corkscrew motion on the ETA-II induction accelerator. To minimize chromatic aberration, we have developed an energy compensation scheme which reduces energy sweep and differential phase advance within a beam pulse. To minimize the misalignment errors, we have developed a time-independent steering algorithm which minimizes the observed corkscrew amplitude averaged over the beam pulse. The steering algorithm can be used even if the monitor spacing is much greater than the system's cyclotron wavelength and the corkscrew motion caused by a given misaligned magnet is fully developed, i.e., the relative phase advance is greater than 2π. (Author) 5 figs., 11 refs

Interpretation of Mutation Induction by Accelerated Very Heavy Ions in Bacteria

International Nuclear Information System (INIS)

Kozubek, S.; Ryznar, L.; Krasavin, E.A.

1994-01-01

We propose a simple approach for the calculation of the frequency of mutation induction in bacteria. The approach is based on the calculation of the fraction of energy deposited by accelerated particles in indirect hits, e.i. events in which the particle does not pass through the cell, however, the cell is hit by δ-electrons. This descriptor of the radiation field has been evaluated for different values of the particle energy and different radii of sensitive structure. Four models of the track structure have been used for calculations. The results have been compared with experimental data on mutation induction in bacteria. Two different modes of particle mutagenic action can be distinguished. Available experimental data agree reasonably well with the results of the presented theory if appropriate track structure is taken. Very good results have been obtained with the track structure models of Kudryashov, 1973 and Chatterjee and Magee, 1973. 23 refs., 6 figs., 1 tab

The effect of leachate recirculation with enzyme cellulase addition on waste stability in landfill bioreactor

Science.gov (United States)

Saffira, N.; Kristanto, G. A.

2018-01-01

Landfill bioreactor with leachate recirculation is known to enhance waste stabilization. However, the composition of waste in Indonesia is comprised by organic waste which is lignocellulosic materials that considered take a long time to degrade under anaerobic condition. To accelerate the degradation process, enzyme addition is ought to do. Cellulase is an enzyme that can catalyse cellulose and other polysaccharide decomposition processes. Therefore, operation of waste degradation using leachate recirculation with a cellulase addition to enhance waste stabilization was investigated using anaerobic bioreactor landfill. The experiment was performed on 2 conditions; leachate recirculation with cellulase addition and recirculation only as a control. The addition of cellulase is reported to be significant in decreasing organic content, represented by volatile solid parameter. The volatile solid reduction in the cellulase augmented reactor and control reactor was 17.86% and 7.90%, respectively. Cellulase addition also resulted in the highest cellulose reduction. Settlement of the landfill in a bioreactor with enzyme addition (32.67%) was reported to be higher than the control (19.33%). Stabilization of landfill review by the decreasing rate constant of the cellulose and lignin ratio parameter was more rapidly achieved by the enzyme addition (0.014 day-1) compared to control (0.002 day-1).

Accelerator development at Bates

International Nuclear Information System (INIS)

Sargent, C.P.

1983-01-01

The past year has seen the completion of a major expansion of the Bates Accelerator Laboratory. A second experimental hall, South Hall, and several magnetic spectrometers have been constructed. The accelerator's maximum energy has been raised from 400 to 750 MeV by means of beam recirculation. A current two-year project for the fabrication of an additional RF transmitter plus a 30% increase in RF peak power capability will increase energy further to ca. 1 GeV. During the same period pulse-to-pulse beam sharing between the high-resolution spectrometer area and South Hall will become available. In January 1981 the Laboratory submitted their ''Proposal for a Long-Range Expansion Program'' to DOE-NSF. The proposed development consists of three stages. Stage I calls for the addition of a pulse stretcher ring to furnish a CW beam to the South Hall beam lines. Additional experimental space for internal target experiments and photon tagging research are also included. Stage II increases the accelerator energy to 2.1 GeV (at 140 microamps) by means of a five-pass head-to-tail recirculator. Stage III is, at this time, a plan rather than a proposal. It increases accelerator energy to 4 GeV by extending the accelerator length and power and adds another pulse stretcher ring and three new experimental areas for the higher energy work. This paper discusses each of these stages in detail and recommends their funding and scheduling

Closed recirculation-Water treatment

International Nuclear Information System (INIS)

Hamza, Hamza B.; Ben Ali, Salah; Saad, Mohamed A.; Traish, Massud R.

2005-01-01

This water treatment is a practical work applied in the center, for a closed recirculation-water system. The system had experienced a serious corrosion problem, due to the use of inadequate water. This work includes chemical preparation for the system. Water treatment, special additives, and follow-up, which resulted in the stability of the case. This work can be applied specially for closed recirculation warm, normal, and chilled water. (author)

The Experimental Study of Rayleigh-Taylor Instability using a Linear Induction Motor Accelerator

Science.gov (United States)

Yamashita, Nicholas; Jacobs, Jeffrey

2009-11-01

The experiments to be presented utilize an incompressible system of two stratified miscible liquids of different densities that are accelerated in order to produce the Rayleigh-Taylor instability. Three liquid combinations are used: isopropyl alcohol with water, a calcium nitrate solution or a lithium polytungstate solution, giving Atwood numbers of 0.11, 0.22 and 0.57, respectively. The acceleration required to drive the instability is produced by two high-speed linear induction motors mounted to an 8 m tall drop tower. The motors are mounted in parallel and have an effective acceleration length of 1.7 m and are each capable of producing 15 kN of thrust. The liquid system is contained within a square acrylic tank with inside dimensions 76 x76x184 mm. The tank is mounted to an aluminum plate, which is driven by the motors to create constant accelerations in the range of 1-20 g's, though the potential exists for higher accelerations. Also attached to the plate are a high-speed camera and an LED backlight to provide continuous video of the instability. In addition, an accelerometer is used to provide acceleration measurements during each experiment. Experimental image sequences will be presented which show the development of a random three-dimensional instability from an unforced initial perturbation. Measurements of the mixing zone width will be compared with traditional growth models.

Critical system issues and modeling requirements - the problem of beam energy sweep in an electron linear induction accelerator

International Nuclear Information System (INIS)

Turner, W.C.; Barrett, D.M.; Sampayan, S.E.

1991-01-01

In this paper the authors attempt to motivate the development of modeling tools for linear induction accelerator components by giving examples of performance limitations related to energy sweep. The most pressing issues is the development of an accurate model of the switching behavior of large magnetic cores at high dB/dt in the accelerator and magnetic compression modulators. Ideally one would like to have a model with as few parameters as possible that allows the user to choose the core geometry and magnetic material and perhaps a few parameters characterizing the switch model. Beyond this, the critical modeling tasks are: simulation of a magnetic compression modulator, modeling the reset dynamics of a magnetic compression modulator, modeling the loading characteristics of a linear induction accelerator cell, and modeling the electron injector current including the dynamics of feedback modulation and beam loading in an accelerator cell. Of course in the development of these models care should be given to benchmarking them against data from experimental systems. Beyond that one should aim for tools that have predictive power so that they can be used as design tools and not merely to replicate existing data

Powerful accelerators for bremsstrahlung and electron beams generation on the basis of inductive energy-storage elements

Energy Technology Data Exchange (ETDEWEB)

Diyankov, V S; Kovalev, V P; Kormilitsin, A I; Lavrentev, B N [All-Russian Research Institute of Technical Physics, Snezhinsk (Russian Federation)

1997-12-31

The report summarizes RFNC-VNIITF activities from 1963 till 1995, devoted to the development of pulsed electron accelerators on the basis of inductive energy storage with electroexplosive wires. These accelerators are called IGUR. The activities resulted in the development of a series of generators of powerful radiation being cheap and easy in manufacturing and servicing. The accelerators achieved the following maximum parameters: diode voltage up to 6 MV, diode current up to 80 kA, current of the extracted electron beam 30 kA, density of the extracted electron beam energy 500 J/cm{sup 2}, bremsstrahlung dose 250000 Rads, and bremsstrahlung dose rate 10{sup 13} Rads/sec. (author). 3 tabs., 5 figs., 7 refs.

Powerful accelerators for bremsstrahlung and electron beams generation on the basis of inductive energy-storage elements

International Nuclear Information System (INIS)

Diyankov, V.S.; Kovalev, V.P.; Kormilitsin, A.I.; Lavrentev, B.N.

1996-01-01

The report summarizes RFNC-VNIITF activities from 1963 till 1995, devoted to the development of pulsed electron accelerators on the basis of inductive energy storage with electroexplosive wires. These accelerators are called IGUR. The activities resulted in the development of a series of generators of powerful radiation being cheap and easy in manufacturing and servicing. The accelerators achieved the following maximum parameters: diode voltage up to 6 MV, diode current up to 80 kA, current of the extracted electron beam 30 kA, density of the extracted electron beam energy 500 J/cm 2 , bremsstrahlung dose 250000 Rads, and bremsstrahlung dose rate 10 13 Rads/sec. (author). 3 tabs., 5 figs., 7 refs

RF accelerating unit installed in the PSB

CERN Multimedia

CERN PhotoLab

1972-01-01

RF accelerating unit installed in the PSB ring between two bending magnets. Cool air from a heat exchanger is injected into the four cavities from the central feeder and the hot air recirculated via the lateral ducts.

The bio-ethanol production with the thin stillage recirculation

Directory of Open Access Journals (Sweden)

M. Rakin

2009-01-01

Full Text Available In this paper, the bioethanol production with the thin stillage recirculation in mashing was investigated. The mashing was performed with recirculation of: 0, 10, 20 and 30 % of the thin stillage. The thin stillage recirculation was repeated six times. In the experiment without the thin stillage, the recirculation bioethanol yield (compared to the theoretical yield was 97.96 %, which implicates that the experiment conditions were chosen and performed well. With the addition of the thin stillage, the bioethanol yield increased and was above 100 %. Higher bioethanol yield than 100 % can be explained by the fact that the thin stillage contains carbohydrates, amino acids and yeast cells degradation products. The bioethanol yield increased with the increased number of thin stillage recirculation cycles. Dry matter content in fermenting slurry increased with the increased thin stillage quantity and the number of the thin stillage recirculation cycles (8.04 % for the first and 9.40 % for the sixth cycle. Dry matter content in thin stillage increased with the increased thin stillage quantity and the number of thin stillage recirculation cycles. Based on the obtained results it can be concluded that thin stillage recirculation increased the bioethanol yield. The highest bioethanol yields were obtained with recirculation of 10% thin stillage.

NGL recovery increase through natural gasoline recirculation

Energy Technology Data Exchange (ETDEWEB)

Rivas M., M.; Bracho, J.L.; Murray, J. [Lagoven S.A., Maracaibo (Venezuela). Western Div.

1997-12-31

Given that the gas being processed in the compression plants Tia Juana 2 (PCTJ-2) and Tia Juana 3 (PCTJ-3) of Lagoven, S.A., an operating affiliate of Petroleos de Venezuela, S.A. has become learner through time, current production of natural gas liquids (NGL) and plant efficiency are significantly lower, compared to design and first obtained values. In this sense and aimed at increasing propane production, an optimization study on condensate stream recirculation and absorber installation was carried out to affect the process equilibrium constants thereby obtaining deeper extraction. Recirculation streams options were recirculation of natural gasoline obtained from the downstream fractionation process and recirculation of a conditioned, unfractionated, deethanized condensate stream. From the study, the natural gasoline recirculation scheme was determined to be the most efficient NGL recovery process. Accordingly, Lagoven, S.A. has undertaken a project to carry out this optimization scheme in PCTJ-2 and PCTJ-3. Construction stages are currently underway with completion scheduled at the end of 1997.

Plasma-focused cyclic accelerators

International Nuclear Information System (INIS)

Mondelli, A.A.; Chernin, D.P.

1985-01-01

The use of ambient plasma to neutralize the transverse forces of an intense particle beam has been known for many years. Most recently, the so-called ion-focused regime (IFR) for beam propagation has been used as a means of focusing intense electron beams in linear accelerators and suggested for injecting an electron beam across magnetic field lines into a high-current cyclic accelerator. One technique for generating the required background plasma for IFR propagation is to use a laser to ionize ambient gas in the accelerator chamber. This paper discusses an alternative means of plasma production for IFR, viz. by using RF breakdown. For this approach the accelerator chamber acts as a waveguide. This technique is not limited to toroidal accelerators. It may be applied to any accelerator or recirculator geometry as well as for beam steering and for injection or extraction of beams in closed accelerator configurations

Low inductance diode design on the Proto II accelerator for imploding plasma loads

International Nuclear Information System (INIS)

Hsing, W.W.; Coats, R.; McDaniel, D.H.; Spielman, R.B.

1985-01-01

A new water transmission line convolute, single piece insulator, and double disk feed has been designed and tested on the .125 ohm, 10 TW Proto II accelerator. The water transmission lines have a 5 cm gap to eliminate any water arcing. A two-dimensional magnetic field code was used to calculate the convolute inductance. The authors used an acrylic insulator as well as a single piece, laminated polycarbonate insulator. They have been successfully tested at over 90% of the Shipman criteria for classical insulator breakdown, although the laminations in the polycarbonate insulator failed after a few shots. The anode and cathode each have two pieces and are held together mechanically. The vacuum MITL tapers to a 3 mm minimum gap. The total inductance is 8.4 nH for gas puff loads and 7.8 nH for imploding foil loads

A detailed BWR recirculation loop model for RELAP

Energy Technology Data Exchange (ETDEWEB)

Araiza-Martínez, Enrique, E-mail: enrique.araiza@inin.gob.mx; Ortiz-Villafuerte, Javier, E-mail: javier.ortiz@inin.gob.mx; Castillo-Durán, Rogelio, E-mail: rogelio.castillo@inin.gob.mx

2017-01-15

Highlights: • A new detailed BWR recirculation loop model was developed for RELAP. • All jet pumps, risers, manifold, suction and control valves, and recirculation pump are modeled. • Model is tested against data from partial blockage of two jet pumps. • For practical applications, simulation results showed good agreement with available data. - Abstract: A new detailed geometric model of the whole recirculation loop of a BWR has been developed for the code RELAP. This detailed model includes the 10 jet pumps, 5 risers, manifold, suction and control valves, and the recirculation pump, per recirculation loop. The model is tested against data from an event of partial blockage at the entrance nozzle of one jet pump in both recirculation loops. For practical applications, simulation results showed good agreement with data. Then, values of parameters considered as figure of merit (reactor power, dome pressure, core flow, among others) for this event are compared against those from the common 1 jet pump per loop model. The results show that new detailed model led to a closer prediction of the reported power change. The detailed recirculation loop model can provide more reliable boundary condition data to a CFD models for studies of, for example, flow induced vibration, wear, and crack initiation.

Experimental demonstration of the KEK induction synchrotron

International Nuclear Information System (INIS)

Takayama, Ken; Torikai, Kota; Shimosaki, Yoshito; Kono, Tadaaki; Iwashita, Taiki; Arakida, Yoshio; Nakamura, Eiji; Shirakata, Masashi; Sueno, Takeshi; Wake, Masayoshi; Otsuka, Kazunori

2007-01-01

Recent progress in the KEK induction synchrotron is presented. In the recent experiment, by using a newly developed induction acceleration system instead of radio-wave acceleration devices, a single proton bunch injected from the 500 MeV Booster ring and captured by the barrier bucket created by the induction step-voltages was accelerated to 6 GeV in the KEK proton synchrotron

Chaotic dynamics in accelerator physics

International Nuclear Information System (INIS)

Cary, J.R.

1992-01-01

Substantial progress was in several areas of accelerator dynamics. For developing understanding of longitudinal adiabatic dynamics, and for creating efficiency enhancements of recirculating free-electron lasers, was substantially completed. A computer code for analyzing the critical KAM tori that bound the dynamic aperture in circular machines was developed. Studies of modes that arise due to the interaction of coating beams with a narrow-spectrum impedance have begun. During this research educational and research ties with the accelerator community at large have been strengthened

Exhaust gas recirculation system for an internal combustion engine

Science.gov (United States)

Wu, Ko-Jen

2013-05-21

An exhaust gas recirculation system for an internal combustion engine comprises an exhaust driven turbocharger having a low pressure turbine outlet in fluid communication with an exhaust gas conduit. The turbocharger also includes a low pressure compressor intake and a high pressure compressor outlet in communication with an intake air conduit. An exhaust gas recirculation conduit fluidly communicates with the exhaust gas conduit to divert a portion of exhaust gas to a low pressure exhaust gas recirculation branch extending between the exhaust gas recirculation conduit and an engine intake system for delivery of exhaust gas thereto. A high pressure exhaust gas recirculation branch extends between the exhaust gas recirculation conduit and the compressor intake and delivers exhaust gas to the compressor for mixing with a compressed intake charge for delivery to the intake system.

Tuning the DARHT Axis-II linear induction accelerator focusing

Energy Technology Data Exchange (ETDEWEB)

Ekdahl, Carl A. [Los Alamos National Laboratory

2012-04-24

Flash radiography of large hydrodynamic experiments driven by high explosives is a well-known diagnostic technique in use at many laboratories, and the Dual-Axis Radiography for Hydrodynamic Testing (DARHT) facility at Los Alamos produces flash radiographs of large hydrodynamic experiments. Two linear induction accelerators (LIAs) make the bremsstrahlung radiographic source spots for orthogonal views of each test. The 2-kA, 20-MeV Axis-I LIA creates a single 60-ns radiography pulse. The 1.7-kA, 16.5-MeV Axis-II LIA creates up to four radiography pulses by kicking them out of a longer pulse that has a 1.6-{mu}s flattop. The Axis-II injector, LIA, kicker, and downstream transport (DST) to the bremsstrahlung converter are described. Adjusting the magnetic focusing and steering elements to optimize the electron-beam transport through an LIA is often called 'tuning.' As in all high-current LIAs, the focusing field is designed to be as close to that of the ideal continuous solenoid as physically possible. In ideal continuous solenoidal transport a smoothly varying beam size can easily be found for which radial forces balance, and the beam is said to be 'matched' to the focusing field. A 'mismatched' beam exhibits unwanted oscillations in size, which are a source of free energy that contributes to emittance growth. This is undesirable, because in the absence of beam-target effects, the radiographic spot size is proportional to the emittance. Tuning the Axis-II LIA is done in two steps. First, the solenoidal focusing elements are set to values designed to provide a matched beam with little or no envelope oscillations, and little or no beam-breakup (BBU) instability growth. Then, steering elements are adjusted to minimize the motion of the centroid of a well-centered beam at the LIA exit. This article only describes the design of the tune for the focusing solenoids. The DARHT Axis-II LIA was required to be re-tuned after installing an

A Recirculating Linac-Based Facility for Ultrafast X-Ray Science

International Nuclear Information System (INIS)

Corlett, J. N.; Barletta, W. A.; DeSantis, S.; Doolittle, L.; Fawley, W. M.; Green, M.A.; Heimann, P.; Leone, S.; Lidia, S.; Li, D.; Ratti, A.; Robinson, K.; Schoenlein, R.; Staples, J.; Wan, W.; Wells, R.; Wolski, A.; Zholents, A.; Parmigiani, F.; Placidi, M.; Pirkl, W.; Rimmer, R. A.; Wang, S.

2003-01-01

We present an updated design for a proposed source of ultra-fast synchrotron radiation pulses based on a recirculating superconducting linac [1,2], in particular the incorporation of EUV and soft x-ray production. The project has been named LUX--Linac-based Ultrafast X-ray facility. The source produces intense x-ray pulses with duration of 10-100 fs at a 10 kHz repetition rate, with synchronization of 10's fs, optimized for the study of ultra-fast dynamics. The photon range covers the EUV to hard x-ray spectrum by use of seeded harmonic generation in undulators, and a specialized technique for ultra-short pulse photon production in the 1-10 keV range. High brightness rf photocathodes produce electron bunches which are optimized either for coherent emission in free electron lasers, or to provide a large x/y emittance ration and small vertical emittance which allows for manipulation to produce short-pulse hard x-rays. An injector linac accelerates the beam to 120 MeV, and is followed by f our passes through a 600-720 MeV recirculating linac. We outline the major technical components of the proposed facility

Direct measurement of the image displacement instability in a linear induction accelerator

Science.gov (United States)

Burris-Mog, T. J.; Ekdahl, C. A.; Moir, D. C.

2017-06-01

The image displacement instability (IDI) has been measured on the 20 MeV Axis I of the dual axis radiographic hydrodynamic test facility and compared to theory. A 0.23 kA electron beam was accelerated across 64 gaps in a low solenoid focusing field, and the position of the beam centroid was measured to 34.3 meters downstream from the cathode. One beam dynamics code was used to model the IDI from first principles, while another code characterized the effects of the resistive wall instability and the beam break-up (BBU) instability. Although the BBU instability was not found to influence the IDI, it appears that the IDI influences the BBU. Because the BBU theory does not fully account for the dependence on beam position for coupling to cavity transverse magnetic modes, the effect of the IDI is missing from the BBU theory. This becomes of particular concern to users of linear induction accelerators operating in or near low magnetic guide fields tunes.

INFLUENCE OF SLUDGE RECIRCULATION ON NUTRIENT REMOVAL IN SUBMERGED MEMBRANE BIOREACTORS

Directory of Open Access Journals (Sweden)

María Casamitjanaa Causa

2015-06-01

Full Text Available Membrane bioreactors (MBR technology is a well-developed wastewater treatment process; however, the integrated operation between biological reactions and physical filtration has been poorly studied. Among other operational parameters, optimal control of sludge recirculation can enhance nitrogen and phosphorous removal processes, but the effects on sludge filterability is not clear. In this paper, different recirculation flow rates were tested to evaluate consequences on sludge filterability and nutrient removal in a MBR-UCT pilot plant treating real municipal wastewater. Three distinct sludge recirculation flows were studied during 10 weeks [external recirculation (from the membrane tank to the anoxic reactor, anoxic recirculation (from the aerobic to the anoxic reactor and anaerobic recirculation (from the anoxic to the anaerobic reactor]. The obtained results have shown that anaerobic recirculation affected nutrient removal in an inversely proportional way, whereas anoxic recirculation had a directly proportional effect. Referring sludge characteristics, filterability and capillarity suction time (CST remained independent of sludge recirculation, whereas CST is proportional to transmembrane pressure (TMP, which seems to depend on external and anoxic sludge recirculation.

The bio-ethanol production with the thin stillage recirculation

OpenAIRE

M. Rakin; J. Pejin; O. Grujić; Lj. Mojović; D. Pejin

2009-01-01

In this paper, the bioethanol production with the thin stillage recirculation in mashing was investigated. The mashing was performed with recirculation of: 0, 10, 20 and 30 % of the thin stillage. The thin stillage recirculation was repeated six times. In the experiment without the thin stillage, the recirculation bioethanol yield (compared to the theoretical yield) was 97.96 %, which implicates that the experiment conditions were chosen and performed well. With the addition of the thin still...

Design of a MeV, 4kA linear induction accelerator for flash radiography

International Nuclear Information System (INIS)

Kulke, B.; Brier, R.; Chapin, W.

1981-01-01

For verifying the hydrodynamics of nuclear weapons design it is useful to have flash x-ray machines that can deliver a maximum dose in a minimum pulse length and with very high reliability. At LLNL, such a requirement was identified some years ago as 500 roentgens at one meter, in a 60 nsec pulse length. In response to this requirement, a linear induction accelerator was proposed to and funded by DOE in 1977. The design of this machine, called FXR, has now been completed and construction has begun. The FXR design extends the parameters of a similar machine that had been built and operated at LBL, Berkeley, some ten years ago. Using a cold cathode injector followed by 48 accelerator modules rated at 400 kV each, the FXR machine will accelerate a 4 kA electron beam pulse to 20 MeV final energy. Key design features are the generation and the stable transport of a low emittance (100 mr-cm) beam from a field emitter diode, the design of reliable, compact energy storage components such as Blumleins, feedlines and accelerator modules, and a computer-assisted control system

NGL recovery being hiked by natural-gasoline recirculation

Energy Technology Data Exchange (ETDEWEB)

Rivas M, M.; Bracho, J.L. [Lagoven S.A., Maracaibo (Venezuela); Murray, J.E. [Murray (James E.), Corpus Christi, TX (United States)

1997-07-07

Construction will be completed later this year at two compression plants operated by Lagoven, S.A., to install natural-gasoline recirculation to improve NGL recovery. The project is the result of a study of condensate-stream recirculation and absorber operations at the compression plants Tia Juana 2 (PCTJ-2) and Tia Juana 3 (PCTJ-3), offshore Lake Maracaibo in western Venezuela. The PCTJ-2 and PCTJ-3 gas compression plants have two systems: gas compression and NGL extraction. Previous analysis of the NGL extraction and fractionation processes of Lagoven determined that there are two practical and attractive alternatives for the recirculation of the condensate streams in PCTJ-2 and 3: recirculation of natural gasoline from the Ule LPG plant; recirculation of a conditioned condensate from the de-ethanizer tower of each plant. Both alternatives are discussed. Also described are fractionation capacity, and modifications for adding absorption and fractionation.

Conceptual design for an accelerator system for a very high-intensity pulsed neutron source using a linear-induction accelerator

International Nuclear Information System (INIS)

Foss, M.H.

1981-01-01

Several accelerator-based intense neutron sources have been constructed or designed by various laboratories around the world. All of these facilities have a common scheme of a linac and synchrotron or accumulator ring, and the system produces the proton energy of 500 to 1000 MeV. The average beam currents range from a few mA to a few hundred mA. The protons are then used to generate high-flux neutrons by spallation out of heavy-metal targets. In a synchrotron system, the protons are already bunched, and thus the pulse rate of the neutron beam is that of the repetition rate of the synchrotron. For an accumulator system, the pulse rate is determined by the extraction repetition rate of the accumulator. We have conceptually designed a new system that uses a linear-induction accelerator which can be operated for an average beam current up to a few mA with a repetition rate up to 100 Hz. The details of the design will be given

Status of the 25URC accelerator

International Nuclear Information System (INIS)

Ziegler, N.F.; Mills, G.D.; Meigs, M.J.; McPherson, R.L.; Juras, R.C.; Jones, C.M.; Haynes, D.L.; Alton, G.D.

1987-01-01

This paper discusses the operation of the 25URC accelerator. Shaft and charging chain life, new corona point holder, recirculating gas stripper, an air-SF 6 separator, and replication of chopped beam pulse are discussed. Seven new ion species were provided for experiment. 2 refs., 2 figs., 2 tabs

Exhaust gas recirculation apparatus for internal combustion engine

Energy Technology Data Exchange (ETDEWEB)

Shigemori, M; Eguchi, N

1975-01-07

An exhaust gas recirculation device to reduce nitrogen oxides emission from internal combustion engines is described. The recirculation is achieved by employing a tube connecting between the exhaust pipe and intake tube. A throttle valve is installed within the exhaust pipe between the muffler and recirculation tube, and regulated by exhaust gas temperature. Whenever the gas temperature is high, the valve closes and increases the gas flow to the intake tube. A temperature sensor is installed within the exhaust pipe and controls a solenoid or magnetic air valve linking to the throttle valve through a relay. The recirculation tube can be cooled by a fan to improve the engine power.

The radon daughter radiation hazard in controlled recirculation systems

International Nuclear Information System (INIS)

Rolle, R.; Burton, R.C.

1987-01-01

In deep South African gold mines, controlled recirculation systems with air cooling are being used to an increasing extent to improve the thermal environment. Recirculation causes some air to reside in the working area for a longer time than would have occurred without recirculation. Since radon daughters grow spontaneously from radon there is some concern that, with the extended residence time, the potential radiation hazard could increase to an unacceptable level. This paper describes the results obtained from a theoretical model of a controlled recirculation system. Guidelines for the design of recirculation systems to control the radon daughter radiation, and to keep it within acceptable limits are provided. 3 refs., 5 figs

FFAGS for muon acceleration

International Nuclear Information System (INIS)

Berg, J. Scott; Kahn, Stephen; Palmer, Robert; Trbojevic, Dejan; Johnstone, Carol; Keil, Eberhard; Aiba, Masamitsu; Machida, Shinji; Mori, Yoshiharu; Ogitsu, Toru; Ohmori, Chihiro; Sessler, Andrew; Koscielniak, Shane

2003-01-01

Due to their finite lifetime, muons must be accelerated very rapidly. It is challenging to make the magnets ramp fast enough to accelerate in a synchrotron, and accelerating in a linac is very expensive. One can use a recirculating accelerator (like CEBAF), but one needs a different arc for each turn, and this limits the number of turns one can use to accelerate, and therefore requires significant amounts of RF to achieve the desired energy gain. An alternative method for muon acceleration is using a fixed field alternating gradient (FFAG) accelerator. Such an accelerator has a very large energy acceptance (a factor of two or three), allowing one to use the same arc with a magnetic field that is constant over time. Thus, one can in principle make as many turns as one can tolerate due to muon decay, therefore reducing the RF cost without increasing the arc cost. This paper reviews the current status of research into the design of FFAGs for muon acceleration. Several current designs are described and compared. General design considerations are also discussed

The SAT Protein of Porcine Parvovirus Accelerates Viral Spreading through Induction of Irreversible Endoplasmic Reticulum Stress.

Science.gov (United States)

Mészáros, István; Tóth, Renáta; Olasz, Ferenc; Tijssen, Peter; Zádori, Zoltán

2017-08-15

The SAT protein (SATp) of porcine parvovirus (PPV) accumulates in the endoplasmic reticulum (ER), and SAT deletion induces the slow-spreading phenotype. The in vitro comparison of the wild-type Kresse strain and its SAT knockout (SAT - ) mutant revealed that prolonged cell integrity and late viral release are responsible for the slower spreading of the SAT - virus. During PPV infection, regardless of the presence or absence of SATp, the expression of downstream ER stress response proteins (Xbp1 and CHOP) was induced. However, in the absence of SATp, significant differences in the quantity and the localization of CHOP were detected, suggesting a role of SATp in the induction of irreversible ER stress in infected cells. The involvement of the induction of irreversible ER stress in porcine testis (PT) cell necrosis and viral egress was confirmed by treatment of infected cells by ER stress-inducing chemicals (MG132, dithiothreitol, and thapsigargin), which accelerated the egress and spreading of both the wild-type and the SAT - viruses. UV stress induction had no beneficial effect on PPV infection, underscoring the specificity of ER stress pathways in the process. However, induction of CHOP and its nuclear translocation cannot alone be responsible for the biological effect of SAT, since nuclear CHOP could not complement the lack of SAT in a coexpression experiment. IMPORTANCE SATp is encoded by an alternative open reading frame of the PPV genome. Earlier we showed that SATp of the attenuated PPV NADL-2 strain accumulates in the ER and accelerates virus release and spreading. Our present work revealed that slow spreading is a general feature of SAT - PPVs and is the consequence of prolonged cell integrity. PPV infection induced ER stress in infected cells regardless of the presence of SATp, as demonstrated by the morphological changes of the ER and expression of the stress response proteins Xbp1 and CHOP. However, the presence of SATp made the ER stress more severe and

Induction linacs and pulsed power

International Nuclear Information System (INIS)

Caporaso, G.J.

1995-01-01

Progress in electronic power conversion technology is making possible a new class of induction linacs that can operate at extremely high repetition rates. Advances in insulator technology, pulse forming line design and switching may also lead to a new type of high current accelerator with accelerating gradients at least an order of magnitude greater than those attainable today. The evolution of the induction accelerator pulsed power system will be discussed along with some details of these emerging technologies which are at the frontiers of accelerator technology

BWR recirculation pump diagnostic expert system

International Nuclear Information System (INIS)

Chiang, S.C.; Morimoto, C.N.; Torres, M.R.

2004-01-01

At General Electric (GE), an on-line expert system to support maintenance decisions for BWR recirculation pumps for nuclear power plants has been developed. This diagnostic expert system is an interactive on-line system that furnishes diagnostic information concerning BWR recirculation pump operational problems. It effectively provides the recirculation pump diagnostic expertise in the plant control room continuously 24 hours a day. The expert system is interfaced to an on-line monitoring system, which uses existing plant sensors to acquire non-safety related data in real time. The expert system correlates and evaluates process data and vibration data by applying expert rules to determine the condition of a BWR recirculation pump system by applying knowledge based rules. Any diagnosis will be automatically displayed, indicating which pump may have a problem, the category of the problem, and the degree of concern expressed by the validity index and color hierarchy. The rules incorporate the expert knowledge from various technical sources such as plant experience, engineering principles, and published reports. These rules are installed in IF-THEN formats and the resulting truth values are also expressed in fuzzy terms and a certainty factor called a validity index. This GE Recirculation Pump Expert System uses industry-standard software, hardware, and network access to provide flexible interfaces with other possible data acquisition systems. Gensym G2 Real-Time Expert System is used for the expert shell and provides the graphical user interface, knowledge base, and inference engine capabilities. (author)

The use of induction linacs with nonlinear magnetic drive as high average power accelerators

International Nuclear Information System (INIS)

Birx, D.L.; Cook, E.G.; Hawkins, S.A.; Newton, M.A.; Poor, S.E.; Reginato, L.L.; Schmidt, J.A.; Smith, M.W.

1985-01-01

The marriage of induction linac technology with Nonlinear Magnetic Modulators has produced some unique capabilities. It appears possible to produce electron beams with average currents measured in amperes, at gradients exceeding 1 MeV/m, and with power efficiences approaching 50%. A 2 MeV, 5 kA electron accelerator is under construction at Lawrence Livermore National Laboratory (LLNL) to allow us to demonstrate some of these concepts. Progress on this project is reported here. (orig.)

Low inductance diode design of the Proto 2 accelerator for imploding plasma loads

Science.gov (United States)

Hsing, W. W.; Coats, R.; McDaniel, D. H.; Spielman, R. B.

A new water transmission line convolute, single piece insulator, and double accelerator. The water transmission lines have a 5 cm gap to eliminate any water arcing. A two-dimensional magnetic field code was used to calculate the convolute inductance. An acrylic insulator was used as well as a single piece, laminated polycarbonate insulator. They have been successfully tested at over 90% of the Shipman criteria for classical insulator breakdown, although the laminations in the polycarbonate insulator failed after a few shots. The anode and cathode each have two pieces and are held together mechanically. The vacuum MITL tapers to a 3 mm minimum gap. The total inductance is 8.4 nH for gas puff loads and 7.8 nH for imploding foil loads. Out of a forward-going energy of 290 kJ, 175 kJ has been delivered past the insulator, and 100 kJ has been successfully delivered to the load.

Power ion beam production in an accelerator with inductive microsecond storage and plasmaerosion switch

International Nuclear Information System (INIS)

Mesyats, G.A.; Didenko, A.N.; Abdullin, Eh.N.; Tomskij Politekhnicheskij Inst.

1986-01-01

Results of investigations into powerful ion beam (PIB) production in an accelerator with inductive microsecond storage and plasmaerosion switch (PES) are given. The storage consists of the 100 kJ high-voltage pulse generator, the inductive load as a vacuum coaxial line. Coaxial line was divided into two regions with PES plasma guns. Generation of converging PIB on switching of energy flux from the first region to the second was performed in the PES area itself as well as in an additional diode during its placing at different distances from PES. The investigations have shown that microsecond PES is an effective element providing PIB eneration with durations of an order of tens of nanoseconds. Total PIB energy contribution is in the range of 3-6 kJ which constitutes 40-50% of total energy release in PES

Design of inductively detuned RF extraction cavities for the Relativistic Klystron Two Beam Accelerator

International Nuclear Information System (INIS)

Henestroza, E.; Yu, S.S.; Li, H.

1995-04-01

An inductively detuned traveling wave cavity for the Relativistic Klystron Two Beam Accelerator expected to extract high RF power at 11. 424 GHz for the 1 TeV Center of Mass Next Linear Collider has been designed. Longitudinal beam dynamics studies led to the following requirements on cavity design: (a) Extraction of 360 MW of RF power with RF component of the current being 1.15 kAmps at 11.424 GHz, (b) Inductively detuned traveling wave cavity with wave phase velocity equal to 4/3 the speed of light, (c) Output cavity with appropriate Q ext and eigenfrequency for proper matching. Furthermore, transverse beam dynamics require low shunt impedances to avoid the beam break-up instability. We describe the design effort to meet these criteria based on frequency-domain and time-domain computations using 2D- and 3D- electromagnetic codes

Approaching maximal performance of longitudinal beam compression in induction accelerator drivers

International Nuclear Information System (INIS)

Mark, J.W.K.; Ho, D.D.M.; Brandon, S.T.; Chang, C.L.; Drobot, A.T.; Faltens, A.; Lee, E.P.; Krafft, G.A.

1986-01-01

Longitudinal beam compression is an integral part of the US induction accelerator development effort for heavy ion fusion. Producing maximal performance for key accelerator components is an essential element of the effort to reduce driver costs. We outline here initial studies directed towards defining the limits of final beam compression including considerations such as: maximal available compression, effects of longitudinal dispersion and beam emittance, combining pulse-shaping with beam compression to reduce the total number of beam manipulations, etc. The use of higher ion charge state Z greater than or equal to 3 is likely to test the limits of the previously envisaged beam compression and final focus hardware. A more conservative approach is to use additional beamlets in final compression and focus. On the other end of the spectrum of choices, alternate approaches might consider new final focus with greater tolerances for systematic momentum and current variations. Development of such final focus concepts would also allow more compact (and hopefully cheaper) hardware packages where the previously separate processes of beam compression, pulse-shaping and final focus occur as partially combined and nearly concurrent beam manipulations

Particle acceleration by inverse-Weibel instability

International Nuclear Information System (INIS)

Kawata, S.

1996-01-01

A high demagnetization rate delta B/delta t can be obtained through fast decoupling of a magnetic field from an electric circuit which generates the magnetic field. Nowadays fast decoupling is possible by present switching technologies. A high particle-acceleration gradient can be obtained in an inductive acceleration system compared with that in a conventional induction accelerator. Based on this new proposal, inductive ion and electron accelerations were investigated numerically. The mechanism presented can be considered as pseudo-inverse Weibel instability. (author). 3 figs., 7 refs

Particle acceleration by inverse-Weibel instability

Energy Technology Data Exchange (ETDEWEB)

Kawata, S [Nagaoka Univ. of Technology (Japan). Dept. of Electrical Engineering

1997-12-31

A high demagnetization rate delta B/delta t can be obtained through fast decoupling of a magnetic field from an electric circuit which generates the magnetic field. Nowadays fast decoupling is possible by present switching technologies. A high particle-acceleration gradient can be obtained in an inductive acceleration system compared with that in a conventional induction accelerator. Based on this new proposal, inductive ion and electron accelerations were investigated numerically. The mechanism presented can be considered as pseudo-inverse Weibel instability. (author). 3 figs., 7 refs.

KEK digital accelerator

Directory of Open Access Journals (Sweden)

T. Iwashita

2011-07-01

Full Text Available The High Energy Accelerator Research Organization KEK digital accelerator (KEK-DA is a renovation of the KEK 500 MeV booster proton synchrotron, which was shut down in 2006. The existing 40 MeV drift tube linac and rf cavities have been replaced by an electron cyclotron resonance (ECR ion source embedded in a 200 kV high-voltage terminal and induction acceleration cells, respectively. A DA is, in principle, capable of accelerating any species of ion in all possible charge states. The KEK-DA is characterized by specific accelerator components such as a permanent magnet X-band ECR ion source, a low-energy transport line, an electrostatic injection kicker, an extraction septum magnet operated in air, combined-function main magnets, and an induction acceleration system. The induction acceleration method, integrating modern pulse power technology and state-of-art digital control, is crucial for the rapid-cycle KEK-DA. The key issues of beam dynamics associated with low-energy injection of heavy ions are beam loss caused by electron capture and stripping as results of the interaction with residual gas molecules and the closed orbit distortion resulting from relatively high remanent fields in the bending magnets. Attractive applications of this accelerator in materials and biological sciences are discussed.

Device for controlling a recirculation flow in a reactor

International Nuclear Information System (INIS)

Shida, Toichi; Tohei, Kazushige; Hirose, Masao; Nakamura, Hideo.

1976-01-01

Object: To provide an emergency cut-off valve in a recirculation system in a reactor to control the recirculation at the time of turbine trip or load cut-off, thereby relieving excessive increase in heat output of fuel. Structure: A recirculation pump is driven through a recirculation pump motor by an AC generator, which is driven by a driving motor through a fluid coupling, so that reactor water passes the emergency cut-off valve and recirculation flow stop valve and then passes a jet pump into the core. At the time of turbine trip or load cut-off, the emergency cut-off valve is closed by a hydraulic circuit, whereby core flow is merely decreased by 20 to 30% in a short period of time to restrain excessive increase in heat output. (Yoshino, Y.)

Heavy Ion Fusion Accelerator Research (HIFAR)

International Nuclear Information System (INIS)

1991-04-01

This report discusses the following topics: emittance variations in current-amplifying ion induction lina; transverse emittance studies of an induction accelerator of heavy ions; drift compression experiments on MBE-4 and related emittance; low emittance uniform- density C s + sources for heavy ion fusion accelerator studies; survey of alignment of MBE-4; time-of-flight dependence on the MBE-4 quadrupole voltage; high order calculation of the multiple content of three dimensional electrostatic geometries; an induction linac injector for scaled experiments; induction accelerator test module for HIF; longitudinal instability in HIF beams; and analysis of resonant longitudinal instability in a heavy ion induction linac

Confinement of a high current proton beam in a linear induction accelerator

International Nuclear Information System (INIS)

Kerslick, G.S.; Roth, I.S.; Golkowski, C.; Ivers, J.D.; Nation, J.A.

1987-01-01

A 1 MeV, 6 kA, 50 ns annular proton beam has been generated in a two stage induction linac. Several confinement systems designed to allow propagation through multiple acceleration stages have been studied. In the first, the beam is injected through a half cusp into a 1.4 T solenoidal magnetic field. In the second system the beam is generated in a full cusp diode. The third system discussed relies on collective confinement of the protons by the space charge of the neutralizing electrons. This is in contrast to the previously described systems which rely on magnetic confinement. A comparison between the three methods of transport is made

Ways for improvement of the LIU-5/5000 linear induction accelerator parameters

International Nuclear Information System (INIS)

Bobylev, V.I.; Kapchinskij, I.M.; Lapitskij, Yu.Ya.; Plotnikov, V.K.; Chuvilo, I.V.

1987-01-01

The reasons of limitaions to increase the beam current and improve the quality of beam in the electron linear induction accelerator LIU-5/5000 are studied. The necessity to increase the voltage in the gaps of the electron gun, increase the diameter of the cathode and aperture of the drift tube, accuracy of axial symmetry electron gun current-carrying elements and accuracy of gun fabrication are shown. Stabilization of beam parameters require a new high voltage modulators. Different versions of the linac modernization with the use of transformers with cores of 430 and 600 mm are studied. Technical possibilities at several versions of high voltage modulators are discussed

Direct measurement of the image displacement instability in a linear induction accelerator

Directory of Open Access Journals (Sweden)

T. J. Burris-Mog

2017-06-01

Full Text Available The image displacement instability (IDI has been measured on the 20 MeV Axis I of the dual axis radiographic hydrodynamic test facility and compared to theory. A 0.23 kA electron beam was accelerated across 64 gaps in a low solenoid focusing field, and the position of the beam centroid was measured to 34.3 meters downstream from the cathode. One beam dynamics code was used to model the IDI from first principles, while another code characterized the effects of the resistive wall instability and the beam break-up (BBU instability. Although the BBU instability was not found to influence the IDI, it appears that the IDI influences the BBU. Because the BBU theory does not fully account for the dependence on beam position for coupling to cavity transverse magnetic modes, the effect of the IDI is missing from the BBU theory. This becomes of particular concern to users of linear induction accelerators operating in or near low magnetic guide fields tunes.

Coreless Concept for High Gradient Induction Cell

International Nuclear Information System (INIS)

Krasnykh, Anatoly

2008-01-01

An induction linac cell for a high gradient is discussed. The proposed solid state coreless approach for the induction linac topology (SLIM(reg s ign)) is based on nanosecond mode operation. This mode may have an acceleration gradient comparable with gradients of rf- accelerator structures. The discussed induction system has the high electric efficiency. The key elements are a solid state semiconductor switch and a high electric density dielectric with a thin section length. The energy in the induction system is storied in the magnetic field. The nanosecond current break-up produces the high voltage. The induced voltage is used for acceleration. This manner of an operation allows the use of low voltage elements in the booster part and achieves a high accelerating gradient. The proposed topology was tested in POP (proof of principle) experiments

Influence of leachate recirculation on aerobic and anaerobic decomposition of solid wastes

International Nuclear Information System (INIS)

Bilgili, M. Sinan; Demir, Ahmet; Ozkaya, Bestamin

2007-01-01

In this study, the effect of leachate recirculation on aerobic and anaerobic degradation of municipal solid wastes is determined by four laboratory-scale landfill reactors. The options studied and compared with the traditional anaerobic landfill are: leachate recirculation, landfill aeration, and aeration with leachate recirculation. Leachate quality is regularly monitored by the means of pH, alkalinity, total dissolved solids, conductivity, oxidation-reduction potential, chloride, chemical oxygen demand, ammonia, and total Kjeldahl nitrogen, in addition to generated leachate quantity. Aerobic leachate recirculated landfill appears to be the most effective option in the removal of organic matter and ammonia. The main difference between aerobic recirculated and non-recirculated landfill options is determined at leachate quantity. Recirculation is more effective on anaerobic degradation of solid waste than aerobic degradation. Further studies are going on to determine the optimum operational conditions for aeration and leachate recirculation rates, also with the operational costs of aeration and recirculation

Engine with pulse-suppressed dedicated exhaust gas recirculation

Science.gov (United States)

Keating, Edward J.; Baker, Rodney E.

2016-06-07

An engine assembly includes an intake assembly, a spark-ignited internal combustion engine, and an exhaust assembly. The intake assembly includes a charge air cooler disposed between an exhaust gas recirculation (EGR) mixer and a backpressure valve. The charge air cooler has both an inlet and an outlet, and the back pressure valve is configured to maintain a minimum pressure difference between the inlet of the charge air cooler and an outlet of the backpressure valve. A dedicated exhaust gas recirculation system is provided in fluid communication with at least one cylinder and with the EGR mixer. The dedicated exhaust gas recirculation system is configured to route all of the exhaust gas from the at least one cylinder to the EGR mixer for recirculation back to the engine.

Accelerated proliferation of non-small cell lung cancer cells after induction chemotherapy

International Nuclear Information System (INIS)

El Sharouni, S.Y.; Kal, H.B.

2003-01-01

Induction chemotherapy of non-small cell lung cancer (NSCLC) stage IIIB with gemcitabine and cisplatin for downstaging the tumour with the aim for further treatment with ionising radiation, is one of the treatments for lung cancer employed. The purpose of this study was to investigate the influence of the waiting time for radiotherapy, i.e. the interval between induction chemotherapy and radiotherapy, on the rate of tumour growth. Interval times between end of chemotherapy and day of diagnostic CT, planning CT and first day of radiotherapy were determined. Increase in tumour volume was measured for 23 patients with NSCLC by measuring the primary tumour dimensions on the diagnostic CT made after induction chemotherapy and on the CT used for radiotherapy planning. Volume doubling times were calculated from the time interval between the two CTs and ratio of the volumes on CT planning and CT diagnostic. The mean time interval between end of chemotherapy and day of diagnostic CT was 16 days, till CT planning 66 days and till first day of radiotherapy 76 (29 - 108) days. Tumour doubling times ranged from 9 to 153 days with a mean of 47 days. This is far less than the mean doubling time of NSCL in untreated patients. This study shows that time interval between chemo- and start of radiotherapy varies between 29 to 108 days. The consequence is fast tumour progression as result of accelerated proliferation: mean tumour-doubling times are decreased by a factor of 2 to 4. The gain obtained with induction chemotherapy with regard to volume reduction was practically lost in the waiting time for radiotherapy. We recommend diminishing the time interval between chemo- and radiotherapy to as short as possible

Recent advances in kicker pulser technology for linear induction accelerators

International Nuclear Information System (INIS)

Chen, Y. J.; Cook, E.; Davis, B.; Dehope, W. J.; Yen, B.

1999-01-01

Recent progress in the development and understanding of linear induction accelerator have produced machines with 10s of MeV of beam energy and multi-kiloampere currents. Near-term machines, such as DARHT-2, are envisioned with microsecond pulselengths. Fast beam kickers, based on cylindrical electromagnetic stripline structures, will permit effective use of these extremely high-energy beams in an increasing number of applications. In one application, radiography, kickers were an essential element in resolving temporal evolution of hydrodynamic events by cleaving out individual pulses from long, microsecond beams. Advanced schemes are envisioned where these individual pulses are redirected through varying length beam lines and suitably recombined for stereographic imaging or tomographic reconstruction. Recent advances in fast kickers and their pulsed power technology are described. Kicker pulsers based on both planar triode and all solid-state componentry are discussed and future development plans are presented

Low inductance diode design on the Proto II accelerator for imploding plasma loads

International Nuclear Information System (INIS)

Hsing, W.W.; Coats, R.; McDaniel, D.H.; Spielman, R.B.

1985-01-01

A new water transmission line convolute, single piece insulator, and double disk feed has been designed and tested on the .125 ohm, 10 TW Proto II accelerator. The water transmission lines have a 5 cm gap to eliminate any water arcing. A two-dimensional magnetic field code was used to calculate the convolute inductance. We used an acrylic insulator as well as a single piece, laminated polycarbonate insulator. They have been succuessfully tested at over 90% of the Shipman criteria for classical insulator breakdown, although the laminations in the polycarbonate insulator failed after a few shots. The anode and cathode each have two pieces and are held together mechanically. The vacuum MITL tapers to a 3 mm minimum gap. The total inductance is 8.4 nH for gas puff loads and 7.8 nH for imploding foil loads. Out of a forward-going energy of 290 kJ, 175 kJ has been delivered past the insulator, and 100 kJ has been successfully delivered to the load

The LLNL Flash X-Ray Induction Linear Accelerator (FXR)

International Nuclear Information System (INIS)

Multhauf, L G

2002-01-01

The FXR is an induction linear accelerator used for high-speed radiography at the Lawrence Livermore National Laboratory's Experimental Test Site. It was designed specifically for the radiography of very thick explosive objects. Since its completion in 1982, it has been very actively used for a large variety of explosives tests, and has been periodically upgraded to achieve higher performance. Upgrades have addressed machine reliability, radiographic sensitivity and resolution, two-frame imaging by double pulsing improvements that are described in detail in the paper. At the same time, the facility in which it was installed has also been extensively upgraded, first by adding space for optical and interferometric diagnostics, and more recently by adding a containment chamber to prevent the environmental dispersal of hazardous and radioactive materials. The containment addition also further expands space for new non-radiographic diagnostics. The new Contained Firing Facility is still in the process of activation. At the same time, FXR is continuing to undergo modifications aimed primarily at further increasing radiographic resolution and sensitivity, and at improving double-pulsed performance

Induction of DNA double-strand breaks in hepatoma cell SMMC-7721 by accelerated carbon ion 12C6+

International Nuclear Information System (INIS)

Lei Suwen; Su Xu; Wang Jufang; Zhao Jing; Li Wenjian

2004-01-01

DNA lesions, especially DNA double-strand breaks (dsbs), are looked upon as the dominant molecular effect of radiation action. Dsbs mark the beginning of a cascade of cellular processes that either results in complete repair of the DNA damage or lead to deleterious stages such as mutation, transformation or even cell death. Changing the radiation quality can influence the radiosensitivity of cells in culture. Accelerated particles provide an excellent means of varying the ionization density of the test radiation. With ion beams, the molecular mechanisms underlying the biological consequences of high linear energy transfer (LET) irradiation can be studied and describing radiation action with biophysical models can be tested. In this paper, radiation-induced DNA double-strand breaks (dsbs) were measured in hepatoma SMMC-7721 cells by means of an experimental approach involving pulsed-field gel electrophoresis and densitometric scanning of ethidium bromide stained gels. With this set-up, the induction of dsbs was investigated in SMMC-7721 cells after irradiation with accelerated carbon ions with specific LET 70 keV/μm. The fraction of DNA retained was taken as quantitative measure to calculate absolute yields of induced DNA dsbs. Experimental data shows that the induction of DNA dsbs increasing with the dose of irradiation. Data are compared with published results on dsbs induction in mammalian cells by radiations of comparable LET

Progress in heavy-ion drivers for inertial fusion

International Nuclear Information System (INIS)

Friedman, A.; Bangerter, R.O.; Herrmannsfeldt, W.B.

1995-01-01

This document deals with heavy-ion induction accelerators developed as fusion drivers for Inertial Confinement Fusion power. It presents the results of research aimed at developing drivers having reduced cost and size as well as the Elise accelerator being built at Lawrence Berkeley Laboratory. An experimental program at Lawrence Livermore National Laboratory concerning recirculating induction accelerators is also presented. Eventually, the document provides some information on other elements of the U.S. Heavy-Ion Fusion (HIF) research program: the experimental study of beam merging, a magnetic quadrupole development program and a study of plasma lenses. (TEC). 28 refs., 6 figs

Investigation of induced recirculation during planned ventilation system maintenance

Science.gov (United States)

Pritchard, C.J.; Scott, D.F.; Noll, J.D.; Voss, B.; Leonis, D.

2015-01-01

The Office of Mine Safety and Health Research (OMSHR) investigated ways to increase mine airflow to underground metal/nonmetal (M/NM) mine working areas to improve miners’ health and safety. One of those areas is controlled recirculation. Because the quantity of mine air often cannot be increased, reusing part of the ventilating air can be an effective alternative, if implemented properly, until the capacity of the present system is improved. The additional airflow can be used to provide effective dilution of contaminants and higher flow velocities in the underground mine environment. Most applications of controlled recirculation involve taking a portion of the return air and passing it back into the intake to increase the air volume delivered to the desired work areas. OMSHR investigated a Nevada gold mine where shaft rehabilitation was in progress and one of the two main fans was shut down to allow reduced air velocity for safe shaft work. Underground booster fan operating pressures were kept constant to maintain airflow to work areas, inducing controlled recirculation in one work zone. Investigation into system behavior and the effects of recirculation on the working area during times of reduced primary ventilation system airflow would provide additional information on implementation of controlled recirculation into the system and how these events affect M/NM ventilation systems. The National Institute for Occupational Safety and Health monitored the ventilation district when both main fans were operating and another scenario with one of the units turned off for maintenance. Airflow and contaminants were measured to determine the exposure effects of induced recirculation on miner health. Surveys showed that 19% controlled recirculation created no change in the overall district airflow distribution and a small reduction in district fresh air intake. Total dust levels increased only modestly and respirable dust levels were also low. Diesel particulate matter

Modeling and simulation of the bioprocess with recirculation

Directory of Open Access Journals (Sweden)

Žerajić Stanko

2007-01-01

Full Text Available The bioprocess models with recirculation present an integration of the model of continuous bioreaction system and the model of separation system. The reaction bioprocess is integrated with separation the biomass, formed product, no consumed substrate or inhibitory substance. In this paper the simulation model of recirculation bioprocess was developed, which may be applied for increasing the biomass productivity and product biosynthesis increasing the conversion of a substrate-to-product, mixing efficiency and secondary C02 separation. The goal of the work is optimal bioprocess configuration, which is determined by simulation optimization. The optimal hemostat state was used as referent. Step-by-step simulation method is necessary because the initial bioprocess state is changing with recirculation in each step. The simulation experiment confirms that at the recirculation ratio a. = 0.275 and the concentration factor C = 4 the maximum glucose conversion to ethanol and at a dilution rate ten times larger.

Recirculating steam generator operation at very low power

International Nuclear Information System (INIS)

Holcblat, A.

2001-01-01

The behaviour of recirculating SG's at very low power has been thoroughly investigated by laboratory and on-site tests as well as numerical simulations. A special experimental program dedicated to recirculation threshold determination has been performed on the Freon SG mock-up CLOTAIRE. These laboratory data are completed with transients of feedwater injections at hot stand-by on two instrumented SG's, one boiler type SG and one economizer type SG. The phenomena are different on both types. In boiler SG's, the SG behaves like a U-tube and recirculation stops around 2% load at stand-by temperature and water level. In economizer SG's, the presence of 2 separate down-comers and a divider plate inside the tube bundle allows a recirculation loop by-passing the separators. The mixing of saturated and cold water induced by this loop limits down-comer cooling and thus alleviates the thermal load on the tube sheet. These tests were used to validate the SG transient analysis 1-D code ANETH. (author)

Indoor spread of respiratory infection by recirculation of air: a controllable hazard

International Nuclear Information System (INIS)

Riley, R.L.

1980-01-01

The overall health benefit to be derived from disinfecting air before recirculation is difficult to predict, but as more and more buildings recirculate air without disinfection, the problem of spreading infection increases. Since the cost of disinfection with uv radiation is small and the cost of morbidity from airborne infections immense, the cost-benefit ratio for disinfecting recirculated air may be attractive, even though the protection of occupants would be limited. Recirculation of air in buildings is a relatively new technology that conserves energy. Like most new technologies, it brings new hazards. Disinfection of recirculated air is an appropriate additional technique with which to counter some of the hazards of air recirculation

Retrofitting adjustable speed drives for large induction motors

International Nuclear Information System (INIS)

Wuestefeld, M.R.; Merriam, C.H.; Porter, N.S.

2004-01-01

Adjustable speed drives (ASDs) are used in many power plants to control process flow by varying the speed of synchronous and induction motors. In applications where the flow requirements vary significantly, ASDs reduce energy and maintenance requirements when compared with drag valves, dampers or other methods to control flow. Until recently, high horsepower ASDs were not available for induction motors. However, advances in power electronics technology have demonstrated the reliability and cost effectiveness of ASDs for large horsepower induction motors. Emphasis on reducing operation and maintenance costs and increasing the capacity factor of nuclear power plants has led some utilities to consider replacing flow control devices in systems powered by large induction motors with ASDs. ASDs provide a high degree of reliability and significant energy savings in situations where full flow operation is not needed for a substantial part of the time. This paper describes the basic adjustable speed drive technologies available for large induction motor applications, ASD operating experience and retrofitting ASDs to replace the existing GE Boiling Water Reactor recirculation flow control system

Flue gas recirculation to pellets burner

International Nuclear Information System (INIS)

Loefgren, B.E.; Blohm, T.

1999-05-01

The aim of this project has been to study the influence of flue gas recirculation on the combustion results. Primarily regarding the turbulence, stability and air surplus of the flame, but also the influence on environmental factors (CO and unburnt hydrocarbons). Also studied was the possibility of automatic control of the mixing of recirculating flue gases in the combustion process through the use of a λ-sond and O 2 control Project report from the program: Small scale combustion of biofuels. 9 figs, 8 tabs

Proton induction linacs as high-intensity neutron sources

International Nuclear Information System (INIS)

Keefe, D.; Hoyer, E.

1981-01-01

Proton induction linacs are explored as high intensity neutron sources. The induction linac - concept, properties, experience with electrons, and possibilities - and its limitations for accelerating ions are reviewed. A number of proton induction linac designs are examined with the LIACEP program and general conclusions are given. Results suggest that a proton induction accelerator of the lowest voltage, consistent with good neutron flux, is preferred and could well be cost competitive with the usual rf linac/storage ring designs. (orig.)

Linear induction accelerator requirements for ion fast ignition

International Nuclear Information System (INIS)

Logan, G.

1998-01-01

induction linacs, the purpose of this memo is to explore possible new features and characteristic parameters that induction linacs would need to meet the stringent requirements for beam quality and compression (sufficiently low longitudinal and transverse thermal spread) for ion driven fast ignition. Separately, Ed Lee at LBNL is looking at heavy-ion synchrotrons to meet similar fast ignition requirements. Parameters relating to cost (e.g, total beam-line length and transport quads, total core volt-seconds and power switching) have to be considered in addition to meeting the challenging beam quality requirements for fast ignition compared to conventional HIF. The aim of this preliminary study is to motivate, after critical debate, taking a next step to do more detailed designs, particle simulations, and experimental tests of the most critical accelerator elements and focusing optics, to further assess the feasibility of ion-driven fast ignition

Investigation on inlet recirculation characteristics of double suction centrifugal compressor with unsymmetrical inlet

Science.gov (United States)

Yang, Ce; Wang, Yingjun; Lao, Dazhong; Tong, Ding; Wei, Longyu; Liu, Yixiong

2016-08-01

The inlet recirculation characteristics of double suction centrifugal compressor with unsymmetrical inlet structures were studied in numerical method, mainly focused on three issues including the amounts and differences of the inlet recirculation in different working conditions, the circumferential non-uniform distributions of the inlet recirculation, the recirculation velocity distributions of the upstream slot of the rear impeller. The results show that there are some differences between the recirculation of the front impeller and that of the rear impeller in whole working conditions. In design speed, the recirculation flow rate of the rear impeller is larger than that of the front impeller in the large flow range, but in the small flow range, the recirculation flow rate of the rear impeller is smaller than that of the front impeller. In different working conditions, the recirculation velocity distributions of the front and rear impeller are non-uniform along the circumferential direction and their non-uniform extents are quite different. The circumferential non-uniform extent of the recirculation velocity varies with the working conditions change. The circumferential non-uniform extent of the recirculation velocity of front impeller and its distribution are determined by the static pressure distribution of the front impeller, but that of the rear impeller is decided by the coupling effects of the inlet flow distortion of the rear impeller, the circumferential unsymmetrical distribution of the upstream slot and the asymmetric structure of the volute. In the design flow and small flow conditions, the recirculation velocities at different circumferential positions of the mean line of the upstream slot cross-section of the rear impeller are quite different, and the recirculation velocities distribution forms at both sides of the mean line are different. The recirculation velocity distributions in the cross-section of the upstream slot depend on the static pressure

Dust deposit in recirculation regions

International Nuclear Information System (INIS)

Griemert, R.

1985-03-01

The present report shows investigations, which have been carried out in a closed duct at forward and backward facing steps. Distribution of fluid velocity and fluid fluctuations in and normal to main flow direction as well as the distribution of Reynolds shear stress have been measured. The mass transfer downstream of a backward facing step has been investigated as well. By using graphite-, copper-, tin- and rubber dust, conditions of deposition have been defined experimentally. A serie of photos shows the filling of a recirculation region downstream of a backward facing step with graphite dust. The present investigations allow to avoid deposition of dust in recirculation regions by selecting the fluid numbers in an appropriate way. (orig.) [de

Conceptual design of an L-band recirculating superconducting traveling wave accelerating structure for ILC

International Nuclear Information System (INIS)

Avrakhov, P.; Kanareykin, A.; Liu, Z.; Kazakov, S.; KEK, Tsukuba; Solyak, N.; Yakovlev, V.; Gai, W.

2007-01-01

With this paper, we propose the conceptual design of a traveling wave accelerating structure for a superconducting accelerator. The overall goal is to study a traveling wave (TW) superconducting (SC) accelerating structure for ILC that allows an increased accelerating gradient and, therefore reduction of the length of the collider. The conceptual studies were performed in order to optimize the acceleration structure design by minimizing the surface fields inside the cavity of the structure, to make the design compatible with existing technology, and to determine the maximum achievable gain in the accelerating gradient. The proposed solution considers RF feedback system redirecting the accelerating wave that passed through the superconducting traveling wave acceleration (STWA) section back to the input of the accelerating structure. The STWA structure has more cells per unit length than a TESLA structure but provides an accelerating gradient higher than a TESLA structure, consequently reducing the cost. In this paper, the STWA cell shape optimization, coupler cell design and feedback waveguide solution are considered. We also discuss the field flatness in the superconducting TW structure, the HOM modes and multipactor performance have been studied as well. The proposed TW structure design gives an overall 46% gain over the SW ILC structure if the 10 m long TW structure is employed

Exhaust gas recirculation in a homogeneous charge compression ignition engine

Science.gov (United States)

Duffy, Kevin P [Metamora, IL; Kieser, Andrew J [Morton, IL; Rodman, Anthony [Chillicothe, IL; Liechty, Michael P [Chillicothe, IL; Hergart, Carl-Anders [Peoria, IL; Hardy, William L [Peoria, IL

2008-05-27

A homogeneous charge compression ignition engine operates by injecting liquid fuel directly in a combustion chamber, and mixing the fuel with recirculated exhaust and fresh air through an auto ignition condition of the fuel. The engine includes at least one turbocharger for extracting energy from the engine exhaust and using that energy to boost intake pressure of recirculated exhaust gas and fresh air. Elevated proportions of exhaust gas recirculated to the engine are attained by throttling the fresh air inlet supply. These elevated exhaust gas recirculation rates allow the HCCI engine to be operated at higher speeds and loads rendering the HCCI engine a more viable alternative to a conventional diesel engine.

Sulphur recirculation for reduced boiler corrosion; Minskad pannkorrosion med svavelrecirkulation

Energy Technology Data Exchange (ETDEWEB)

Andersson, Sven; Karlsson, Martin (Goetaverken Miljoe AB, Goeteborg (Sweden)); Blomqvist, Evalena; Baefver, Linda; Claesson, Frida; Davidsson, Kent (SP Sveriges Tekniska Forskningsinstitut, Boraas (Sweden)); Froitzheim, Jan; Pettersson, Jesper; Steenari, Britt-Marie (Chalmers Tekniska Hoegskola, Oorganisk miljoekemi, Goeteborg (Sweden))

2010-03-15

Sulphur recirculation is a new technology for reducing boiler corrosion and dioxin formation, which was demonstrated in full-scale tests performed at the Renova Waste to Energy plant at Saevenaes in Goeteborg (Sweden). Sulphur is recirculated from the flue gas cleaning back to the boiler, which reduces the chloride content of the deposits, which in turn reduces boiler corrosion and dioxin formation. Sulphur dioxide was separated from the flue gas in a wet scrubber by adding hydrogen peroxide, producing sulphuric acid. The sulphuric acid was injected into the furnace using nozzles with atomization air, surrounded by recirculated flue gas for improved mixing. By recirculating the sulphur, the sulphur dioxide concentration was increased in the boiler. Each sulphur atom passed the boiler several times and no external sulphur had to be added. Dioxin, ash, deposits and particle samplings together with 1000 h corrosion probe measurements were performed for normal operation (reference) and with sulphur recirculation respectively. During spring 2009, reference measurements were made and the recirculation system was installed and tested. During autumn 2009, a long term test with sulphur recirculation was made. An SO{sub 2} concentration of approximately 800 mg/m3 (n, d.g.) was maintained in the boiler by the system except during a period of extremely low sulphur content in the waste. The sulphur dioxide stack concentrations have been far below the emission limit. Sulphuric acid dew point measurements have shown that the sulphuric acid dosage did not lead to elevated SO{sub 3} concentrations, which may otherwise lead to low temperature corrosion. The chlorine content of both fly ash and boiler ash decreased and the sulphur content increased during the sulphur recirculation tests. The molar chlorine/sulphur ratio (Cl/S) decreased by two thirds in the fly ash as well as in the boiler ash, except for one sample. With sulphur recirculation in operation, the deposit growth was

High power switches for ion induction linacs

International Nuclear Information System (INIS)

Humphries, S. Jr.; Savage, M.; Saylor, W.B.

1985-01-01

The success of linear induction ion accelerators for accelerator inertial fusion (AIF) applications depends largely on innovations in pulsed power technology. There are tight constraints on the accuracy of accelerating voltage waveforms to maintain a low momentum spread. Furthermore, the non-relativistic ion beams may be subject to a klystron-like interaction with the accelerating cavities leading to enhanced momentum spread. In this paper, the author describe a novel high power switch with a demonstrated ability to interrupt 300 A at 20 kV in less than 60 ns. The switch may allow the replacement of pulse modulators in linear induction accelerators with hard tube pulsers. A power system based on a hard tube pulser could solve the longitudinal instability problem while maintaining high energy transfer efficiency. The problem of longitudinal beam control in ion induction linacs is reviewed in Section 2. Section 3 describes the principles of the plasma flow switch. Experimental results are summarized in Section 4

High power switches for ion induction linacs

International Nuclear Information System (INIS)

Humphries, S.; Savage, M.; Saylor, W.B.

1985-01-01

The success of linear induction ion accelerators for accelerator inertial fusion (AIF) applications depends largely on innovations in pulsed power technology. There are tight constraints on the accuracy of accelerating voltage waveforms to maintain a low momentum spread. Furthermore, the non-relativistic ion beams may be subject to a klystronlike interaction with the accelerating cavities, leading to enhanced momentum spread. In this paper, we describe a novel high power switch with a demonstrated ability to interrupt 300 A at 20 kV in less than 60 ns. The switch may allow the replacement of pulse modulators in linear induction accelerators with hard tube pulsers. A power system based on a hard tube pulser could solve the longitudinal instability problem while maintaining high energy transfer efficiency. The problem of longitudinal beam control in ion induction linacs is reviewed in Section 2. Section 3 describes the principles of the plasma flow switch. Experimental results are summarized in Section 4

Sulfur recirculation for increased electricity production in Waste-to-Energy plants.

Science.gov (United States)

Andersson, Sven; Blomqvist, Evalena W; Bäfver, Linda; Jones, Frida; Davidsson, Kent; Froitzheim, Jan; Karlsson, Martin; Larsson, Erik; Liske, Jesper

2014-01-01

Sulfur recirculation is a new technology for reducing boiler corrosion and dioxin formation. It was demonstrated in full-scale tests at a Waste to Energy plant in Göteborg (Sweden) during nearly two months of operation. Sulfur was recirculated as sulfuric acid from the flue gas cleaning back to the boiler, thus creating a sulfur loop. The new technology was evaluated by extensive measurement campaigns during operation under normal conditions (reference case) and operation with sulfur recirculation. The chlorine content of both fly ash and boiler ash decreased and the sulfur content increased during the sulfur recirculation tests. The deposit growth and the particle concentration decreased with sulfur recirculation and the dioxin concentration (I-TEQ) of the flue gas was reduced by approximately 25%. Sulfuric acid dew point measurements showed that the sulfuric acid dosage did not lead to elevated SO3 concentrations, which may otherwise induce low temperature corrosion. In the sulfur recirculation corrosion probe exposures, the corrosion rate decreased for all tested materials (16Mo3, Sanicro 28 and Inconel 625) and material temperatures (450 °C and 525 °C) compared to the reference exposure. The corrosion rates were reduced by 60-90%. Sulfur recirculation prevented the formation of transition metal chlorides at the metal/oxide interface, formation of chromate and reduced the presence of zinc in the corrosion products. Furthermore, measured corrosion rates at 525 °C with sulfur recirculation in operation were similar or lower compared to those measured at 450 °C material temperature in reference conditions, which corresponds to normal operation at normal steam temperatures. This implies that sulfur recirculation allows for higher steam data and electricity production without increasing corrosion. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

Simultaneously reducing CO2 and particulate exposures via fractional recirculation of vehicle cabin air.

Science.gov (United States)

Jung, Heejung S; Grady, Michael L; Victoroff, Tristan; Miller, Arthur L

2017-07-01

Prior studies demonstrate that air recirculation can reduce exposure to nanoparticles in vehicle cabins. However when people occupy confined spaces, air recirculation can lead to carbon dioxide (CO 2 ) accumulation which can potentially lead to deleterious effects on cognitive function. This study proposes a fractional air recirculation system for reducing nanoparticle concentration while simultaneously suppressing CO 2 levels in the cabin. Several recirculation scenarios were tested using a custom-programmed HVAC (heat, ventilation, air conditioning) unit that varied the recirculation door angle in the test vehicle. Operating the recirculation system with a standard cabin filter reduced particle concentrations to 1000 particles/cm 3 , although CO 2 levels rose to 3000 ppm. When as little as 25% fresh air was introduced (75% recirculation), CO 2 levels dropped to 1000 ppm, while particle concentrations remained below 5000 particles/cm 3 . We found that nanoparticles were removed selectively during recirculation and demonstrated the trade-off between cabin CO 2 concentration and cabin particle concentration using fractional air recirculation. Data showed significant increases in CO 2 levels during 100% recirculation. For various fan speeds, recirculation fractions of 50-75% maintained lower CO 2 levels in the cabin, while still reducing particulate levels. We recommend fractional recirculation as a simple method to reduce occupants' exposures to particulate matter and CO 2 in vehicles. A design with several fractional recirculation settings could allow air exchange adequate for reducing both particulate and CO 2 exposures. Developing this technology could lead to reductions in airborne nanoparticle exposure, while also mitigating safety risks from CO 2 accumulation.

MBE-4: an induction linac experiment for heavy ion fusion

International Nuclear Information System (INIS)

Fessenden, T.J.; Avery, R.T.; Brodzik, D.A.

1986-06-01

The multiple-beam induction linac approach to a heavy ion fusion driver features continuous current amplification along the accelerator and a minimum of transverse beam manipulation from source to pellet. Current amplification and bunch length control require careful shaping of the accelerating voltages. This driver approach exploits developments in electron induction linac technology that have occurred within the last 15 years at LBL, LLNL and NBS. MBE-4 is a four beam induction linac that models much of the accelerator physics of the electrostatically focused section of a considerably longer induction accelerator. Four parallel Cs + beams are electrostatically focussed and will be accelerated from 200 keV to approximately one MeV when the experiment is complete in the spring of 1987. The current in each of the four beams will increase from 10 to 40 mA due to both increase in beam speed and shortening of the bunch length. Results of experiments with the injector and first eight accelerating gaps are presented

Armature design for coaxial induction launchers

International Nuclear Information System (INIS)

Andrews, J.A.; Devine, J.R.

1991-01-01

This paper reports on the armature design for a coaxial induction launcher that is influenced by a large set of highly coupled parameters. The simplifying assumptions often employed in coaxial accelerator analysis, such as a uniform or sinusoidal axial distribution of the azimuthal armature current, are unrealistic in induction launchers with monolithic single-turn armatures. In order to better understand the true dynamic behavior of coaxial accelerators, the Center for Electromechanics at The University of Texas at Austin (CEM-UT) has developed series of computer codes based on the current filament method. By utilizing these performance codes in conjunction with electromagnetic (EM) and mechanical finite element programs, it is now possible to design high performance induction launchers with armatures that can withstand the considerable mechanical and thermal loads inherent in a coaxial accelerator launch

Modeling of velocity field for vacuum induction melting process

Institute of Scientific and Technical Information of China (English)

CHEN Bo; JIANG Zhi-guo; LIU Kui; LI Yi-yi

2005-01-01

The numerical simulation for the recirculating flow of melting of an electromagnetically stirred alloy in a cylindrical induction furnace crucible was presented. Inductive currents and electromagnetic body forces in the alloy under three different solenoid frequencies and three different melting powers were calculated, and then the forces were adopted in the fluid flow equations to simulate the flow of the alloy and the behavior of the free surface. The relationship between the height of the electromagnetic stirring meniscus, melting power, and solenoid frequency was derived based on the law of mass conservation. The results show that the inductive currents and the electromagnetic forces vary with the frequency, melting power, and the physical properties of metal. The velocity and the height of the meniscus increase with the increase of the melting power and the decrease of the solenoid frequency.

Development of circular protons accelerator for ocular teletherapy

International Nuclear Information System (INIS)

Rabelo, L. A.; Campos, T.P.R.

2011-01-01

The proton therapy has been used for ocular tumors providing tumor control in most cases and vision preservations. The protons show high doses in depth depict lower scattering from beam than other particles, electrons and photons. The cyclotron is a type of accelerator that increases the kinetic energy of the charged particle, recirculating it on a magnetic field and crossing an accelerating electrical field. It can be used to produce radioisotopes to hospitals. The goal of this study is to investigate a unit of circular accelerator to be coupled in existing national cyclotrons to generate a proton beams suitable to ocular therapy. Herein, physical parameters are evaluable, including relativistic corrections. That result shows the viability of developing an accelerator unit to ocular proton therapy. (author)

The continuous electron beam accelerator facility

International Nuclear Information System (INIS)

Grunder, H.A.

1989-01-01

Tunnel construction and accelerator component development, assembly, and testing are under way at the Continuous Electron Beam Accelerator Facility. CEBAF's 4-GeV, 200-μA superconducting recirculating accelerator will provide cw beam to simultaneous experiments in three end stations for studies of the nuclear many-body system, its quark substructure, and the strong and electroweak interactions governing this form of matter. Prototype accelerating cavities, assembled in cryostats and tested on site, continue to exceed performance specifications. An on-site liquid helium capability supports cryostat development and cavity testing. Major elements of the accelerator instrumentation and control hardware and software are in use in cryogenics, rf, and injector tests. Prototype rf systems have been operated and prototype klystrons have been ordered. The initial, 100-keV, room-temperature region of the 45-MeV injector is operational and meets specifications. CEBAF's end stations have been conceptually designed; experimental equipment conceptual designs will be completed in 1989. 2 refs., 5 figs., 2 tabs

Thermophysical fundamentals of cyclonic recirculating heating devices

Science.gov (United States)

Karpov, S. V.; Zagoskin, A. A.

2017-10-01

This report presents the results of experimental and theoretical research of aerodynamics and convective heat transfer in cyclone devices with the new system of external recirculation of heating gas under the influence of radial pressure gradient in a heat carrier’s swirling turbulent flow. The dynamic problem of tangential velocity distribution in a clearance volume is solved at various re-circulation ratio values including limiting quantities (kr = 0; 1) and variations in cyclonic combustion chamber’s design parameters and operating conditions (Rer); the integrated calculation ratios for fundamental aerodynamic characteristics of a recirculation device are derived. The first experimental and numerical studies of convective heat transfer on internal and external surfaces of a hollow shaft in a swirling recirculation flow are derived through the instrumentality of OpenFOAM, these studies are also conducted for a setting of several cylindrical solid inserts. The external surface heat problem of a hollow cylindrical insert is solved with integral and digital methods; generalized similarity equations for the internal and external surfaces extended in range of Reynolds number are derived. The experimental data is in reasonable agreement with the derived curves and the results of mathematic modelling of convective heat transfer. Calculation recommendations for optimal selection of kr values at various ratios of their geometric characteristics and products utilization rate are obtained.

Recent progress of the advanced test accelerator

International Nuclear Information System (INIS)

Prono, D.S.

1985-01-01

The Advanced Test Accelerator (ATA) of Lawrence Livermore National Laboratory is a linear induction accelerator whose electron beam parameters are 10 kA, 50 MeV, and 70 ns. This accelerator structure basically is a 2.5 MeV injector followed by 190 identical induction accelerator cores each of which incrementally adds 250 kV to the electron beam as it threads the center of the core. Recent work on beam stability, beam emittance and beam brightness is reported

CEBAF [Continuous Electron Beam Accelerator Facility] design overview and project status

International Nuclear Information System (INIS)

Leemann, C.

1988-01-01

This paper discusses the design and specifications of the Continuous Electron Beam Accelerator Facility. Beam performance objectives are discussed, as well as the recirculating linac concept, the injector, cavities, cryogenic system, beam transport and optics, rf system and construction progress. 19 refs., 10 figs

Monitoring for shaft cracks on reactor recirculation pumps

International Nuclear Information System (INIS)

Kowal, M.G.; O'Brien, J.T. Jr.

1989-01-01

The article discusses the vibration characteristics associated with a boiling water reactor (BWR) recirculation pump. It also describes the application of diagnostic techniques and shaft crack theory to an on-line diagnostic monitoring system for reactor recirculation pumps employed at Philadelphia Electric Company's Peach Bottom Atomic Power Station. Specific emphasis is placed on the unique monitoring techniques associated with these variable speed vertical pumps

A novel angular acceleration sensor based on the electromagnetic induction principle and investigation of its calibration tests.

Science.gov (United States)

Zhao, Hao; Feng, Hao

2013-08-12

An angular acceleration sensor can be used for the dynamic analysis of human and joint motions. In this paper, an angular acceleration sensor with novel structure based on the principle of electromagnetic induction is designed. The method involves the construction of a constant magnetic field by the excitation windings of sensor, and the cup-shaped rotor that cut the magnetic field. The output windings of the sensor generate an electromotive force, which is directly proportional to the angular acceleration through the electromagnetic coupling when the rotor has rotational angular acceleration. The mechanical structure and the magnetic working circuit of the sensor are described. The output properties and the mathematical model including the transfer function and state-space model of the sensor are established. The asymptotical stability of the sensor when it is working is verified by the Lyapunov Theorem. An angular acceleration calibration device based on the torsional pendulum principle is designed. The method involves the coaxial connection of the angular acceleration sensor, torsion pendulum and a high-precision angle sensor, and then an initial external force is applied to the torsion pendulum to produce a periodic damping angle oscillation. The angular acceleration sensor and the angle sensor will generate two corresponding electrical signals. The sensitivity coefficient of the angular acceleration sensor can be obtained after processing these two-channel signals. The experiment results show that the sensitivity coefficient of the sensor is about 17.29 mv/Krad·s2. Finally, the errors existing in the practical applications of the sensor are discussed and the corresponding improvement measures are proposed to provide effective technical support for the practical promotion of the novel sensor.

Induction linacs for heavy ion fusion research

International Nuclear Information System (INIS)

Fessenden, T.J.; Avery, R.T.; Brady, V.; Bisognano, J.; Celata, C.; Chupp, W.W.; Faltens, A.; Hartwig, E.C.; Judd, D.L.; Keefe, D.; Kim, C.H.; Laslett, L.J.; Lee, E.P.; Rosenblum, S.S.; Smith, L.; Warwick, A.

1984-01-01

The new features of employing an induction linac as a driver for inertial fusion involve (1) transport of high-current low-emittance heavy ion beams. (2) multiple independently-focussed beams threading the same accelerator structure, and (3) synthesis of voltage waveforms to accomplish beam current amplification. A research program is underway at LBL to develop accelerators that test all these features with the final goal of producing an ion beam capable of heating matter to proportional70 eV. This paper presents a discussion of some properties of induction linacs and how they may be used for HIF research. Physics designs of the High Temperature Experiment (HTE) and the Multiple Beam Experiment (MBE) accelerators are presented along with initial concepts of the MBE induction units. (orig.)

Induction linacs for heavy ion fusion research

Energy Technology Data Exchange (ETDEWEB)

Fessenden, T.J.

1984-05-01

The new features of employing an induction linac as a driver for inertial fusion involve (1) transport of high-current low-emittance heavy ion beams, (2) multiple independently-focussed beams threading the same accelerator structure, and (3) synthesis of voltage waveforms to accomplish beam current amplification. A research program is underway at LBL to develop accelerators that test all these features with the final goal of producing an ion beam capable of heating matter to approx. 70 eV. This paper presents a discussion of some properties of induction linacs and how they may be used for HIF research. Physics designs of the High Temperature Experiment (HTE) and the Multiple Beam Experiment (MBE) accelerators are presented along with initial concepts of the MBE induction units.

Status of an induction accelerator driven, high-power microwave generator at Livermore

International Nuclear Information System (INIS)

Houck, T.L.; Westenskow, G.A.

1993-01-01

The authors are testing an enhanced version of the Choppertron, a high-power rf generator which shows great promise of achieving greater than 400 MW of output power at 11.4 GHz with stable phase and amplitude. This version of the Choppertron is driven by a 5-MeV, 1-kA induction accelerator beam. Modifications to the original Choppertron included aggressive suppression of high order modes in the two output structures, lengthening of the modulation section to match for higher beam energy, and improved efficiency. Final results of the original Choppertron experiment, status of the ongoing experiment and planned experiments for the next year are presented. The motivation of the research program at the LLNL Microwave Source Facility is to develop microwave sources which could be suitable drivers for a future TeV linear e + e - collider

Measurements and effects of backstreaming ions produced at bremsstrahlung converter target in Dragon-I linear induction accelerator

International Nuclear Information System (INIS)

Yu Haijun; Zhu Jun; Chen Nan; Xie Yutong; Jiang Xiaoguo; Jian Cheng

2010-01-01

Positive ions released from x-ray converter target impacted by electron beam of millimeter spot size can be trapped and accelerated in the incident beam's potential well. As the ions move upstream, the beam will be pinched first and then defocused at the target. Four Faraday cups are used to collect backstreaming ions produced at the bremsstrahlung converter target in Dragon-I linear induction accelerator (LIA). Experimental and theoretical results show that the backstreaming positive ions density and velocity are about 10 21 /m 3 and 2-3 mm/μs, respectively. The theoretical and experimental results of electron beam envelope with ions and without ions are also presented. The discussions show that the backstreaming positive ions will not affect the electron beam focusing and envelope radius in Dragon-I LIA.

Plasma-focused cyclic accelerators

International Nuclear Information System (INIS)

Mondelli, A.A.; Chernin, D.P.

1985-01-01

The use of ambient plasma to neutralize the transverse forces of an intense particle beam has been known for many years. Most recently, the so-called ion-focused regime (IFR) for beam propagation has been used as a means of focusing intense electron beams in linear accelerators and suggested for injecting an electron beam across magnetic field lines into a high-current cyclic accelerator. One technique for generating the required background plasma for IFR propagation is to use a laser to ionize ambient gas in the accelerator chamber. For cyclic accelerators a technique is required for carrying the plasma channel and the beam around a bend. Multiple laser-generated channels with dipole magnetic fields to switch the beam from one channel to the next have been tested at Sandia. This paper discusses an alternative means of plasma production for IFR, viz. by using rf breakdown. For this approach the accelerator chamber acts as a waveguide. With a suitable driving frequency, a waveguide mode can be driven which has its peak field intensity on the axis with negligible fields at the chamber walls. The plasma production and hence the beam propagation is thereby isolated from the walls. This technique is not limited to toroidal accelerators. It may be applied to any accelerator or recirculator geometry as well as for beam steering and for injection or extraction of beams in closed accelerator configurations

Comparison of recirculation configurations for biological nutrient removal in a membrane bioreactor.

Science.gov (United States)

Bekir Ersu, Cagatayhan; Ong, Say Kee; Arslankaya, Ertan; Brown, Patrick

2008-03-01

A 12-L lab-scale membrane bioreactor (MBR), consisting of an anaerobic and anoxic compartment followed by an oxic plate-frame membrane compartment, was evaluated for carbonaceous and nutrient removals by varying the recirculation of mixed liquor and permeate. The hydraulic retention times (HRTs) for the anaerobic, anoxic, and oxic compartments were 2, 2, and 8h, respectively. The solids residence time (SRT) for the oxic compartment was 25 days. Five different recirculation configurations were tested by recirculating mixed liquor and/or permeate recirculation equal to the influent flow rate (identified as 100%) into different locations of the anaerobic and anoxic compartments. Of the five configurations, the configuration with 100% mixed liquor recirculation to the anaerobic compartment and 100% permeate recirculation to the anoxic compartment gave the highest percentage removal with an average 92.3+/-0.5% soluble chemical oxygen demand (sCOD), 75.6+/-0.4% total nitrogen (TN), and 62.4+/-1.3% total phosphorus (TP) removal. When the mixed liquor and permeate recirculation rates were varied for the same configuration, the highest TP removal was obtained for 300% mixed liquor recirculation and 100% permeate recirculation (300%/100%) with a TP removal of 88.1+/-1.3% while the highest TN removal (90.3+/-0.3%) was obtained for 200%/300% recirculation. TN and TP concentrations as low as 4.2+/-0.1 and 1.4+/-0.2mg/L respectively were obtained. Mass loading rates were generally low in the range of 0.11-0.22kgCOD/kgMLSS/d due to high biomass concentrations within the oxic reactor (approx. 8000mg/L). The BioWin model was calibrated against one set of the experimental data and was found to predict the experimental data of effluent TN, TP, and NO(3)(-)-N but over-predicted sCOD and NH(3)-N for various recirculation rates. The anoxic heterotrophic yield for the calibrated model was 0.2kg biomass COD/kg COD utilized while the maximum growth rates were found to be 0.45day(-1) for mu

Cellular and molecular effects for mutation induction in normal human cells irradiated with accelerated neon ions

International Nuclear Information System (INIS)

Suzuki, Masao; Tsuruoka, Chizuru; Kanai, Tatsuaki; Kato, Takeshi; Yatagai, Fumio; Watanabe, Masami

2006-01-01

We investigated the linear energy transfer (LET) dependence of mutation induction on the hypoxanthine-guanine phosphoribosyl transferase (HPRT) locus in normal human fibroblast-like cells irradiated with accelerated neon-ion beams. The cells were irradiated with neon-ion beams at various LETs ranging from 63 to 335 keV/μm. Neon-ion beams were accelerated by the Riken Ring Cyclotron at the Institute of Physical and Chemical Research in Japan. Mutation induction at the HPRT locus was detected to measure 6-thioguanine-resistant clones. The mutation spectrum of the deletion pattern of exons of mutants was analyzed using the multiplex polymerase chain reaction (PCR). The dose-response curves increased steeply up to 0.5 Gy and leveled off or decreased between 0.5 and 1.0 Gy, compared to the response to 137 Cs γ-rays. The mutation frequency increased up to 105 keV/μm and then there was a downward trend with increasing LET values. The deletion pattern of exons was non-specific. About 75-100% of the mutants produced using LETs ranging from 63 to 335 keV/μm showed all or partial deletions of exons, while among γ-ray-induced mutants 30% showed no deletions, 30% partial deletions and 40% complete deletions. These results suggested that the dose-response curves of neon-ion-induced mutations were dependent upon LET values, but the deletion pattern of DNA was not

Measurement and analysis of the electric field radiation in pulsed power system of linear induction accelerator

International Nuclear Information System (INIS)

Cheng Qifeng; Ni Jianping; Meng Cui; Cheng Cheng; Liu Yinong; Li Jin

2009-01-01

The close of high voltage switch in pulsed power system of linear induction accelerator often radiates strong transient electric field, which may influence ambient sensitive electric equipment, signals and performance of other instruments, etc. By performing gridded measurement around the Marx generator, the general distribution law and basic characters of electric field radiation are summarized. The current signal of the discharge circuit is also measured, which demonstrates that the current and the radiated electric field both have a resonance frequency about 150 kHz, and contain much higher frequency components. (authors)

Addition of Arsenic Trioxide into Induction Regimens Could Not Accelerate Recovery of Abnormality of Coagulation and Fibrinolysis in Patients with Acute Promyelocytic Leukemia.

Directory of Open Access Journals (Sweden)

Ye Zhang

Full Text Available All-trans retinoic acid combined to anthracycline-based chemotherapy is the standard regimen of acute promyelocytic leukemia. The advent of arsenic trioxide has contributed to improve the anti-leukemic efficacy in acute promyelocytic leukemia. The objectives of the current study were to evaluate if dual induction by all-trans retinoic acid and arsenic trioxide could accelerate the recovery of abnormality of coagulation and fibrinolysis in patients with acute promyelocytic leukemia.Retrospective analysis was performed in 103 newly-diagnosed patients with acute promyelocytic leukemia. Hemostatic variables and the consumption of component blood were comparably analyzed among patients treated by different induction regimen with or without arsenic trioxide.Compared to patients with other subtypes of de novo acute myeloid leukemia, patients with acute promyelocytic leukemia had lower platelet counts and fibrinogen levels, significantly prolonged prothrombin time and elevated D-dimers (P<0.001. Acute promyelocytic leukemia patients with high or intermediate risk prognostic stratification presented lower initial fibrinogen level than that of low-risk group (P<0.05. After induction treatment, abnormal coagulation and fibrinolysis of patients with acute promyelocytic leukemia was significantly improved before day 10. The recovery of abnormal hemostatic variables (platelet, prothrombin time, fibrinogen and D-dimer was not significantly accelerated after adding arsenic trioxide in induction regimens; and the consumption of transfused component blood (platelet and plasma did not dramatically change either. Acute promyelocytic leukemia patients with high or intermediate risk prognostic stratification had higher platelet transfusion demands than that of low-risk group (P<0.05.Unexpectedly, adding arsenic trioxide could not accelerate the recovery of abnormality of coagulation and fibrinolysis in acute promyelocytic leukemia patients who received all

Volume reduction and material recirculation by freon decontamination

International Nuclear Information System (INIS)

Berners, O.; Buhmann, D.; Yamashita, Y.; Yoshiaki, M.

1989-01-01

This paper discusses the use of freon in a large variety of decontamination in the nuclear and non-nuclear fields. As far as the contamination is loose or smerable, surfaces of nearly all materials can be decontaminated. Freon is electrically non-conductive, chemically neutral and has a low surface tension. So it is capable of creeping under the contaminant and loosening or dissolving it. Used freon can be collected, cleaned and recirculated. Its cleaning can be done easily by evaporation at its lower vapor point of about 48 degrees C (104 degrees F). Good decontamination results could be achieved, expensive materials, tools and equipment could be recirculated. Big volumes of materials could get separated from their contaminants, which is the real radioactive waste. Freon decontamination is an effective, overall economical and approved technology to volume reduction and material recirculation

Induction technology optimization code

International Nuclear Information System (INIS)

Caporaso, G.J.; Brooks, A.L.; Kirbie, H.C.

1992-01-01

A code has been developed to evaluate relative costs of induction accelerator driver systems for relativistic klystrons. The code incorporates beam generation, transport and pulsed power system constraints to provide an integrated design tool. The code generates an injector/accelerator combination which satisfies the top level requirements and all system constraints once a small number of design choices have been specified (rise time of the injector voltage and aspect ratio of the ferrite induction cores, for example). The code calculates dimensions of accelerator mechanical assemblies and values of all electrical components. Cost factors for machined parts, raw materials and components are applied to yield a total system cost. These costs are then plotted as a function of the two design choices to enable selection of an optimum design based on various criteria. (Author) 11 refs., 3 figs

Vortex dynamics in a pipe T-junction: Recirculation and sensitivity

Science.gov (United States)

Chen, Kevin K.; Rowley, Clarence W.; Stone, Howard A.

2015-03-01

In the last few years, many researchers have noted that regions of recirculating flow often exhibit particularly high sensitivity to spatially localized feedback. We explore the flow through a T-shaped pipe bifurcation—a simple and ubiquitous, but generally poorly understood flow configuration—and provide a complex example of the relation between recirculation and sensitivity. When Re ≥ 320, a phenomenon resembling vortex breakdown occurs in four locations in the junction, with internal stagnation points appearing on vortex axes and causing flow reversal. The structure of the recirculation is similar to the traditional bubble-type breakdown. These recirculation regions are highly sensitive to spatially localized feedback in the linearized Navier-Stokes operator. The flow separation at the corners of the "T," however, does not exhibit this kind of sensitivity. We focus our analysis on the Reynolds number of 560, near the first Hopf bifurcation of the flow.

Human amniotic membrane, best healing accelerator, and the choice of bone induction for vestibuloplasty technique (an animal study

Directory of Open Access Journals (Sweden)

Ahad Khoshzaban

2010-12-01

Full Text Available Mohammad H Samandari1, Shahriar Adibi2, Ahad Khoshzaban3, Sara Aghazadeh5, Parviz Dihimi4, Siamak S Torbaghan6, Saeed H Keshel5, Zohreh Shahabi71Department of Oral and Maxillofacial Surgery, Dentistry Faculty, 2Dental Research of Torabinejad Research Centre, 3Iranian Tissue Bank Research and Preparation Centre, Imam Khomeini Hospital Complex, 4Department of Oral and Maxillofacial Pathology, Dentistry Faculty, Isfahan University of Medical Sciences, Isfahan, Iran; 5Stem Cells Preparation Unit, Eye Research Center, Farabi Hospital, 6Department of Pathology, Imam Khomeini Medical Centre, 7BMT Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, IranObjective: To investigate the effects of amniotic membrane (AM in bone induction and wound healing after vestibuloplasty surgery on animal samples while receptacle proteins such as growth factors were considered as accelerators for wound healing and bone induction after these operations.Material and methods: Ten adult dogs (5 females, 5 males; race, Iranian mixed; weight, 44 pounds were included, which underwent surgery for transplantation on mandible and maxillary. AM was used for promoting bone induction and healing.Results: The tissue samples were obtained after 2, 8, and 12 weeks for histology survey. No significant differences were observed between male and female or left and right jaws. AM decreased fibrinoleukocytic exudates and inflammation in the experimental group, had significant effects on bone formation, considerably improves wound healing, and gives rise to bone induction (P < 0.0001.Conclusions: Our study findings indicate that the AM is a suitable cover for different injuries and acellular AM has the potential for rapid improvement and bone induction. The AM contains collagen, laminin, and fibronectin, which provide an appropriate substrate for bone induction. This substrate promoted bone induction and might contribute to induction of the progenitor cells and/or stem

Power plant including an exhaust gas recirculation system for injecting recirculated exhaust gases in the fuel and compressed air of a gas turbine engine

Science.gov (United States)

Anand, Ashok Kumar; Nagarjuna Reddy, Thirumala Reddy; Shaffer, Jason Brian; York, William David

2014-05-13

A power plant is provided and includes a gas turbine engine having a combustor in which compressed gas and fuel are mixed and combusted, first and second supply lines respectively coupled to the combustor and respectively configured to supply the compressed gas and the fuel to the combustor and an exhaust gas recirculation (EGR) system to re-circulate exhaust gas produced by the gas turbine engine toward the combustor. The EGR system is coupled to the first and second supply lines and configured to combine first and second portions of the re-circulated exhaust gas with the compressed gas and the fuel at the first and second supply lines, respectively.

Generation and acceleration of high-current annular electron beam in linear induction accelerator and generation of the power microwave radiation from Cherenkov TWT

International Nuclear Information System (INIS)

Abubakirov, E.V.; Arkhipov, O.V.; Bobyleva, L.V.

1990-01-01

The section of linear induction accelerator (LIA) with a strong guiding magnetic field (up to 1.5 T), with output beam power up to 2 GW and beam pulse duration 60 ns is created and investigated by experiment. The beam energy gain is equal to 10 keV/sm with explosive emission is used; the large length of the beam propagation (1.5 m) without spolling of the beam with high beam energy gain has been established. The microwave radiation power about 30-100 MW has achieved from relativistic Cherenkov travelling wave tube with high exponential gain on the basis of LIA and high-current diode

Analysis of the FEL-RF interaction in recirculating, energy-recovering linacs with an FEL

CERN Document Server

Merminga, L; Benson, S; Bolshakov, A; Doolittle, L; Neil, George R

1999-01-01

Recirculating, energy-recovering linacs can be used as driver accelerators for high power FELs. Instabilities which arise from fluctuations of the cavity fields are investigated. Energy changes can cause beam loss on apertures, phase oscillations and optical cavity detuning. These effects in turn cause changes in the laser output power through a time-varying FEL gain function. All three effects change the beam-induced voltage in the cavities and can lead to unstable variations of the accelerating field and output laser power. We have developed a model of the coupled system and solved it both analytically and numerically. It includes the beam-cavity interaction, low level RF feedback, and the electron-photon interaction. The latter includes the FEL gain function in terms of cavity detuning, energy offset, and is valid both in the small signal gain and in the saturated regimes. We have demonstrated that in the limit of small perturbations, the linear theory agrees with the numerical solutions and have performed...

Recirculation nursery systems for bivalves

NARCIS (Netherlands)

Kamermans, P.; Blanco Garcia, A.; Joaquim, Sandra; Matias, Domitilia; Magnesen, Thorolf; Nicolas, J.; Petten, Bruno; Robert, Rene

2016-01-01

n order to increase production of bivalves in hatcheries and nurseries, the development of new technology and its integration into commercial bivalve hatcheries is important. Recirculation aquaculture systems (RASs) have several advantages: high densities of the species can be cultured resulting in

Separated-orbit bisected energy-recovered linear accelerator

Science.gov (United States)

Douglas, David R.

2015-09-01

A separated-orbit bisected energy-recovered linear accelerator apparatus and method. The accelerator includes a first linac, a second linac, and a plurality of arcs of differing path lengths, including a plurality of up arcs, a plurality of downgoing arcs, and a full energy arc providing a path independent of the up arcs and downgoing arcs. The up arcs have a path length that is substantially a multiple of the RF wavelength and the full energy arc includes a path length that is substantially an odd half-integer multiple of the RF wavelength. Operation of the accelerator includes accelerating the beam utilizing the linacs and up arcs until the beam is at full energy, at full energy executing a full recirculation to the second linac using a path length that is substantially an odd half-integer of the RF wavelength, and then decelerating the beam using the linacs and downgoing arcs.

Re-circulating linac vacuum system

International Nuclear Information System (INIS)

Wells, Russell P.; Corlett, John N.; Zholents, Alexander A.

2003-01-01

The vacuum system for a proposed 2.5 GeV, 10ΜA recirculating linac synchrotron light source [1] is readily achievable with conventional vacuum hardware and established fabrication processes. Some of the difficult technical challenges associated with synchrotron light source storage rings are sidestepped by the relatively low beam current and short beam lifetime requirements of a re-circulating linac. This minimal lifetime requirement leads directly to relatively high limits on the background gas pressure through much of the facility. The 10ΜA average beam current produces very little synchrotron radiation induced gas desorption and thus the need for an ante-chamber in the vacuum chamber is eliminated. In the arc bend magnets, and the insertion devices, the vacuum chamber dimensions can be selected to balance the coherent synchrotron radiation and resistive wall wakefield effects, while maintaining the modest limits on the gas pressure and minimal outgassing

Impact of capillary rise and recirculation on simulated crop yields

NARCIS (Netherlands)

Kroes, J.G.; Supit, I.; Dam, van J.C.; Walsum, van P.E.V.; Mulder, H.M.

2018-01-01

Upward soil water flow is a vital supply of water to crops. The purpose of this study is to determine if upward flow and recirculated percolation water can be quantified separately, and to determine the contribution of capillary rise and recirculated water to crop yield and groundwater recharge.

Test Stand for Linear Induction Accelerator Optimization

International Nuclear Information System (INIS)

Ong, M; DeHope, B; Griffin, K; Goerz, D; Kihara, R; Vogtlin, G; Zentler, J M; Scarpetti, R

2003-01-01

Lawrence Livermore National Laboratory has designed and constructed a test stand to improve the voltage regulation in our Flash X-Ray (FXR) accelerator cell. The goal is to create a more mono-energetic electron beam that will create an x-ray source with a smaller spot size. Studying the interaction of the beam and pulse-power system with the accelerator cell will improve the design of high-current accelerators at Livermore and elsewhere. On the test stand, a standard FXR cell is driven by a flexible pulse-power system and the beam current is simulated with a switched center conductor. The test stand is fully instrumented with high-speed digitizers to document the effect of impedance mismatches when the cell is operated under various full-voltage conditions. A time-domain reflectometry technique was also developed to characterize the beam and cell interactions by measuring the impedance of the accelerator and pulse-power component. Computer models are being developed in parallel with the testing program to validate the measurements and evaluate different design changes. Both 3D transient electromagnetic and circuit models are being used

CEBAF: A superconducting radio frequency accelerator for nuclear physics

International Nuclear Information System (INIS)

Hartline, B.K.

1988-01-01

The Continuous Electron Beam Accelerator Facility (CEBAF) will be a 4-GeV, 200-μA superconducting recirculating linear accelerator to provide CW electron beams to simultaneous nuclear physics experiments in three end stations. Funded by the Department of Energy, CEBAF's purpose is basic research on the nuclear many-body system, its quark substructure, and the strong and electroweak interactions governing this form of matter. At the heart of the accelerator are niobium superconducting accelerating cavities designed at Cornell University and successfully prototyped with industry during the past three years. The cavities consistently exceed CEBAF's performance specifications (gradient ≥ 5 MV/m, Q 0 ≥ 2.4 /times/ 10 9 at 2 K and 5 MV/m). Construction is under way, and operation is scheduled in 1994. 26 refs., 9 figs., 3 tabs

Treatment of vinasses - recirculation

Directory of Open Access Journals (Sweden)

Germán Andrés Castro Moreno

2009-08-01

Full Text Available The purpose of this minireview is to give an overview of treatments that have been applied on the vinasse, residue from the alcoholic fermentation; appoint some of its advantages and disadvantages, and then submit recirculation, as one of the best options from an economic point of view and easy implementation, for those who are not interested in the ethanol byproducts.

Domestic manufacturing and reliability improvement of reactor water recirculation equipment

International Nuclear Information System (INIS)

Kobayashi, Hidekazu; Oi, Masao; Shida, Toichi; Yokomori, Takashi

1982-01-01

The reactor coolant recirculation system is one of the important systems to control the reactor output in BWR nuclear power plants. Its components require high reliability and maintainability as well as controllability. For many Japanese nuclear power plants, recirculation pumps, fluid couplings and others have been imported so far. Hitachi Ltd. has established a domestic manufacturing organization through the development and test of these equipment. The fundamental design conditions for these equipment are the improvement of the rate of utilization of plant facility, the capability to follow load, and output power stability. In this paper, the specifications, the investigation of moment of inertia and the design features of recirculation pumps, driving motors and variable frequency power supply systems are described. The paper also reports on the combination test implemented to evaluate the recirculation system. The combination test includes the test using water rheostat for the power source facility and the loading test for a recirculation pump. The application of those system equipment to an actual plant was analyzed and evaluated on a basis of the test data obtained. The result showed that the equipment can achieve the rate of change of reactor power of 30%/min. Those equipment have been employed for No. 2 reactor plant of the Fukushima No. 2 Nuclear Power Station, the Tokyo Electric Power Co., Inc. (Wakatsuki, Y.)

Radionuclide buildup in BWR [boiling water reactor] reactor coolant recirculation piping

International Nuclear Information System (INIS)

Duce, S.W.; Marley, A.W.; Freeman, A.L.

1989-12-01

Since the spring of 1985, thermoluminescent dosimeter, dose rate, and gamma spectral data have been acquired on the contamination of boiling water reactor primary coolant recirculation systems as part of a Nuclear Regulatory Commission funded study. Data have been gathered for twelve facilities by taking direct measurements and/or obtaining plant and vendor data. The project titled, ''Effectiveness and Safety Aspects of Selected Decontamination Processes'' (October 1983) initially reviewed the application of chemical decontamination processes on primary coolant recirculation system piping. Recontamination of the system following pipe replacement or chemical decontamination was studied as a second thrust of this program. During the course of this study, recontamination measurements were made at eight different commercial boiling water reactors. At four of the reactors the primary coolant recirculation system piping was chemically decontaminated. At the other four the piping was replaced. Vendor data were obtained from two boiling water reactors that had replaced the primary coolant recirculation system piping. Contamination measurements were made at two newly operating boiling water reactors. This report discusses the results of these measurements as they apply to contamination and recontamination of boiling water reactor recirculation piping. 16 refs., 29 figs., 9 tabs

An Improved SF6 System for the FXR Induction Linac Blumlein Switches

International Nuclear Information System (INIS)

DeHope, W; Kihara, R; Griffin, K L; Ong, M; Ross, T

2007-01-01

The now-mature FXR (Flash X-Ray) radiographic facility at Lawrence Livermore National Laboratory will be briefly described with emphasis on its pulsed power system. The heart of each accelerating cell's pulse forming Blumlein is it's sulfur hexafluoride-based triggered closing switch. FXR's recent upgrade to a recirculating SF 6 gas reclamation system will be described and the resulting accelerator performance and reliability improvements documented. This was accompanied by a detailed switch breakdown study on FXR's Test Stand and the recent analysis of the resulting statistics will be shown

Low Load Model of a Once-through Boiler with Recirculation

DEFF Research Database (Denmark)

Trangbæk, Klaus

2006-01-01

A dynamic simulation model of a once-through boiler in low to medium load is developed. When the system is in low load, water from the evaporator is recirculated through a bottle. This recirculation system is included in the model, which is then shown to fit closed-loop data from a real plant...

Coastal recirculation potential affecting air pollutants in Portugal: The role of circulation weather types

Science.gov (United States)

Russo, Ana; Gouveia, Célia; Levy, Ilan; Dayan, Uri; Jerez, Sonia; Mendes, Manuel; Trigo, Ricardo

2016-06-01

Coastal zones are under increasing development and experience air pollution episodes regularly. These episodes are often related to peaks in local emissions from industry or transportation, but can also be associated with regional transport from neighbour urban areas influenced by land-sea breeze recirculation. This study intends to analyze the relation between circulation weather patterns, air mass recirculation and pollution levels in three coastal airsheds of Portugal (Lisbon, Porto and Sines) based on the application of an objective quantitative measure of potential recirculation. Although ventilation events have a dominant presence throughout the studied 9-yrs period on all the three airsheds, recirculation and stagnation conditions occur frequently. The association between NO2, SO2 and O3 levels and recirculation potential is evident during summer months. Under high average recirculation potential and high variability, NO2 and SO2 levels are higher for the three airsheds, whilst for O3 each airshed responds differently. This indicates a high heterogeneity among the three airsheds in (1) the type of emission - traffic or industry - prevailing for each contaminant, and (2) the response to the various circulation weather patterns and recirculation situations. Irrespectively of that, the proposed methodology, based on iterative K-means clustering, allows to identify which prevailing patterns are associated with high recirculation potential, having the advantage of being applicable to any geographical location.

SLIA beam line design

International Nuclear Information System (INIS)

Petillo, J.; Chernin, D.; Kostas, C.; Mondelli, A.

1990-01-01

The Spiral Line Induction Accelerator (SLIA) is a multi-kiloampere compact electron accelerator. It uses linear induction accelerator modules on the straight sections of a racetrack spiral, with strong-focusing bends to recirculate the electrons. The strong focusing is provided by stellarator windings on the bends. Stellarator coils are used to provide the strong focusing on the bends. The matching of the electron beam from a diode through a series of accelerator modules and stellarator bends is a major issue in the design of this accelerator. The beam line design for a proof-of-concept SLIA experiment (10 kA, 7 MeV) to be carried out at Pulse Sciences, Inc. will be presented. The design will demonstrate beam matching from element to element in the focusing system, the design of an achromatic bend, and the requirements for avoiding collective instabilities

High current induction linacs

International Nuclear Information System (INIS)

Barletta, W.; Faltens, A.; Henestroza, E.; Lee, E.

1994-07-01

Induction linacs are among the most powerful accelerators in existence. They have accelerated electron bunches of several kiloamperes, and are being investigated as drivers for heavy ion driven inertial confinement fusion (HIF), which requires peak beam currents of kiloamperes and average beam powers of some tens of megawatts. The requirement for waste transmutation with an 800 MeV proton or deuteron beam with an average current of 50 mA and an average power of 40 MW lies midway between the electron machines and the heavy ion machines in overall difficulty. Much of the technology and understanding of beam physics carries over from the previous machines to the new requirements. The induction linac allows use of a very large beam aperture, which may turn out to be crucial to reducing beam loss and machine activation from the beam halo. The major issues addressed here are transport of high intensity beams, availability of sources, efficiency of acceleration, and the state of the needed technology for the waste treatment application. Because of the transformer-like action of an induction core and the accompanying magnetizing current, induction linacs make the most economic sense and have the highest efficiencies with large beam currents. Based on present understanding of beam transport limits, induction core magnetizing current requirements, and pulse modulators, the efficiencies could be very high. The study of beam transport at high intensities has been the major activity of the HIF community. Beam transport and sources are limiting at low energies but are not significant constraints at the higher energies. As will be shown, the proton beams will be space-charge-dominated, for which the emittance has only a minor effect on the overall beam diameter but does determine the density falloff at the beam edge

The Continuous Electron Beam Accelerator Facility

International Nuclear Information System (INIS)

Grunder, H.A.; Bisognano, J.J.; Diamond, W.I.; Hartline, B.K.; Leemann, C.W.; Mougey, J.; Sundelin, R.M.; York, R.C.

1987-01-01

On February 13, 1987, construction started on the Continuous Electron Beam Accelerator Facility - a 4-GeV, 200-μA, continuous beam, electron accelerator facility designed for nuclear physics research. The machine has a racetrack configuration with two antiparallel, 500-MeV, superconducting linac segments connected by beam lines to allow four passes of recirculation. The accelerating structure consists of 1500-MHz, five-cell niobium cavities developed at Cornell University. A liquid helium cryogenic system cools the cavities to an operating temperature of 2 K. Beam extraction after any three of the four passes allows simultaneous delivery of up to three beams of independently variable currents and different, but correlated, energies to the three experimental areas. Beam breakup thresholds exceed the design current by nearly two orders of magnitude. Project completion and the start of physics operations are scheduled for 1993. The total estimated cost is $255 million

The benefits of flue gas recirculation in waste incineration.

Science.gov (United States)

Liuzzo, Giuseppe; Verdone, Nicola; Bravi, Marco

2007-01-01

Flue gas recirculation in the incinerator combustion chamber is an operative technique that offers substantial benefits in managing waste incineration. The advantages that can be obtained are both economic and environmental and are determined by the low flow rate of fumes actually emitted if compared to the flue gas released when recirculation is not conducted. Simulations of two incineration processes, with and without flue gas recirculation, have been carried out by using a commercial flowsheeting simulator. The results of the simulations demonstrate that, from an economic point of view, the proposed technique permits a greater level of energy recovery (up to +3%) and, at the same time, lower investment costs as far as the equipment and machinery constituting the air pollution control section of the plant are concerned. At equal treatment system efficiencies, the environmental benefits stem from the decrease in the emission of atmospheric pollutants. Throughout the paper reference is made to the EC legislation in the field of environmental protection, thus ensuring the general validity in the EU of the foundations laid and conclusions drawn henceforth. A numerical example concerning mercury emission quantifies the reported considerations and illustrates that flue gas recirculation reduces emission of this pollutant by 50%.

High-current beam transport in electrostatic accelerator tubes

International Nuclear Information System (INIS)

Ramian, G.; Elais, L.

1987-01-01

The UCSB Free Electron Laser (FEL) has successfully demonstrated the use of a commercial 6 megavolt electrostatic accelerator as a high current beam source in a recirculating configuration. The accelerator, manufactured by National Electrostatics Corp. (NEC), Middleton WI, uses two standard high gradient accelerator tubes. Suppression of ion multiplication was accomplished by NEC with apertures and a shaped electrostatic field. This field shaping has fortuitously provided a periodically reversing radial field component with sufficient focusing strength to transport electron beams of up to 3 Amps current. Present two-stage FEL work requires a 20 Amp beam and proposed very high voltage FEL designs require currents as high as 100 Amps. A plan to permit transport of such high current beams by the addition of solenoidal focussing elements is described

High current pulsed ion inductor accelerator for destruction of radioactive wastes

Energy Technology Data Exchange (ETDEWEB)

Korenev, S A; Puzynin, I V; Samojlov, V N; Sissakyan, A N [Joint Institute for Nuclear Research, Dubna (Russian Federation)

1997-12-31

A new high-current pulsed linear induction accelerator proposed for application in beam-driven transmutation technologies is described. The accelerator consists of an ion injector, of ion separation and induction accelerating systems, and of an output system for extracting an ion beam into open air. An ion source with explosive ion emission, capable of producing various kinds of ions, is used as an injector. The ion separator exploits a pulsed magnetic system. The induction acceleration structure includes inductors with amorphous iron cores. Imbedded magnetic elements assure the ion beam transport. Main parameters of the accelerator are given in the paper and the design of an ion injector is discussed in more detail. (J.U.). 3 figs., 3 refs.

High current pulsed ion inductor accelerator for destruction of radioactive wastes

International Nuclear Information System (INIS)

Korenev, S.A.; Puzynin, I.V.; Samojlov, V.N.; Sissakyan, A.N.

1996-01-01

A new high-current pulsed linear induction accelerator proposed for application in beam-driven transmutation technologies is described. The accelerator consists of an ion injector, of ion separation and induction accelerating systems, and of an output system for extracting an ion beam into open air. An ion source with explosive ion emission, capable of producing various kinds of ions, is used as an injector. The ion separator exploits a pulsed magnetic system. The induction acceleration structure includes inductors with amorphous iron cores. Imbedded magnetic elements assure the ion beam transport. Main parameters of the accelerator are given in the paper and the design of an ion injector is discussed in more detail. (J.U.). 3 figs., 3 refs

Discussion of the effects of recirculating exhaust air on performance and efficiency of a typical microturbine

International Nuclear Information System (INIS)

De Paepe, Ward; Delattin, Frank; Bram, Svend; De Ruyck, Jacques

2012-01-01

This paper reports on a specific phenomenon, noticed during steam injection experiments on a microturbine. During the considered experiments, measurements indicated an unsteady inlet air temperature of the compressor, resulting in unstable operation of the microturbine. Non-continuous exhaust air recirculation was a possible explanation for the observed behaviour of the microturbine. The aim of this paper is to investigate and demonstrate the effects of exhaust recirculation on a microgasturbine. Depending on wind direction, exhaust air re-entered the engine, resulting in changing inlet conditions which affects the operating regime of the microturbine. For this paper, a series of experiments were performed in the wind tunnel. These series of experiments allowed investigation of the effect of the wind direction on flue gasses flow. Next to the experiments, steady-state simulations of exhaust recirculation were performed in order to study the effect of exhaust recirculation on thermodynamic performance of the microturbine. Dynamic simulations of the non-continuous recirculation revealed the effects of frequency and amplitude on average performance and stability. Results from simulations supported the important impact of exhaust recirculation. Wind tunnel tests demonstrated the influence of the wind direction on recirculation and revealed the necessity to heighten the stack, thus preventing exhaust recirculation. -- Highlights: ► Unstable operation of a T100 microturbine during steam injection tests was noticed, caused by exhaust gas recirculation. ► Wind tunnel tests were performed to study the effect of the wind direction on the recirculation process. ► Steady-state simulations to investigate the effect of exhaust gas recirculation on thermodynamic performance. ► Dynamic simulations to reveal effects of frequency and amplitude on average performance and stability. ► Wind tunnel tests revealed the necessity to heighten the stack to prevent exhaust

Preoperational test report, recirculation condenser cooling systems

Energy Technology Data Exchange (ETDEWEB)

Clifton, F.T.

1997-11-04

This represents a preoperational test report for Recirculation Condenser Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The four system provide condenser cooling water for vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102. Each system consists of a valved piping loop, a pair of redundant recirculation pumps, a closed-loop evaporative cooling tower, and supporting instrumentation; equipment is located outside the farm on concrete slabs. Piping is routed to the each ventilation condenser inside the farm via below-grade concrete trenches. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

Preoperational test report, recirculation condenser cooling systems

International Nuclear Information System (INIS)

Clifton, F.T.

1997-01-01

This represents a preoperational test report for Recirculation Condenser Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The four system provide condenser cooling water for vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102. Each system consists of a valved piping loop, a pair of redundant recirculation pumps, a closed-loop evaporative cooling tower, and supporting instrumentation; equipment is located outside the farm on concrete slabs. Piping is routed to the each ventilation condenser inside the farm via below-grade concrete trenches. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System

High average-power induction linacs

International Nuclear Information System (INIS)

Prono, D.S.; Barrett, D.; Bowles, E.

1989-01-01

Induction linear accelerators (LIAs) are inherently capable of accelerating several thousand amperes of /approximately/ 50-ns duration pulses to > 100 MeV. In this paper we report progress and status in the areas of duty factor and stray power management. These technologies are vital if LIAs are to attain high average power operation. 13 figs

R and D status of high-current accelerators at IFP

International Nuclear Information System (INIS)

Deng, J. J.; Shi, J. S.; Xie, W. P.

2011-01-01

High-current accelerators have many important applications in Z-pinches, high-power microwaves, and free electron lasers, imploding liners and radiography and so on. Research activities on Z-pinches, imploding liners, radiography at the Institute of Fluid Physics (IFP) are introduced. Several main high-current accelerators developed and being developed at IFP are described, such as the Linear Induction Accelerator X-Ray Facility Upgrade (LIAXFU, 12 MeV, 2.5 kA, 90 ns), the Dragon-I linear induction accelerator (20 MeV, 2.5 kA, 60 ns), and the Primary Test Stand for Z-pinch (PTS, 10 MA, 120 ns). The design of Dragon-II linear induction accelerator (20 MeV, 2.5 kA, 3 x 60 ns) to be built will be presented briefly.

Linear induction accelerators at the Los Alamos National Laboratory DARHT facility

International Nuclear Information System (INIS)

Nath, Subrata

2010-01-01

The Dual-Axis Radiographic Hydrodynamic Test Facility (DARHT) at Los Alamos National Laboratory consists of two linear induction accelerators at right angles to each other. The First Axis, operating since 1999, produces a nominal 20-MeV, 2-kA single beam-pulse with 60-nsec width. In contrast, the DARHT Second Axis, operating since 2008, produces up to four pulses in a variable pulse format by slicing micro-pulses out of a longer ∼1.6-microseconds (flat-top) pulse of nominal beam-energy and -current of 17 MeV and 2 kA respectively. Bremsstrahlung x-rays, shining on a hydro-dynamical experimental device, are produced by focusing the electron beam-pulses onto a high-Z target. Variable pulse-formats allow for adjustment of the pulse-to-pulse doses to record a time sequence of x-ray images of the explosively driven imploding mock device. Herein, we present a sampling of the numerous physics and engineering aspects along with the current status of the fully operational dual axes capability. First successful simultaneous use of both the axes for a hydrodynamic experiment was achieved in 2009.

Impact assessment of concentrate recirculation on the landfill gas production

Directory of Open Access Journals (Sweden)

Džolev Nikola M.

2016-01-01

Full Text Available This paper explores the impact of concentrate recirculation, as a product of leachate treated by reverse osmosis plant, on the production of landfill gas at the real-scale landfill for municipal solid waste. In an effort to come up with results experimental measurements were carried out at the landfill in Bijeljina. All measurements performed, were divided into 3 groups. The aims of two groups of measurement were to determine landfill gas and methane yield from concentrate and leachate in laboratory conditions (1st group and to find out concentrations of oxidizing matters (COD and BOD5 present in leachate and concentrate at different points of treatment as well as its variability over the time (2nd group which could be used to calculate the potential of landfill gas and methane generation from concentrate by recirculation, theoretically. 3rd group of measurements, carried out in parallel, have goal to determine the quality and quantity of the collected landfill gas at wells throughout the landfill. The results of analysis carried out in this experimental research show the clear evidence of concentrate recirculation impact on methane production by increasing the landfill gas flow, as well as its concentration within the landfill gas composition, at the nearby well. Although results indicated relatively high impact of concentrate recirculation on landfill gas production, comparing to its theoretical potential, the influence on the landfill at whole, is negligible, due to relatively low volumes in recirculation with respect to its size and objectively low potential given by organic matter present in concentrate.

Review of induction LINACS

International Nuclear Information System (INIS)

Faltens, A.; Keefe, D.

1981-10-01

There has been a recent upsurge of activity in the field of induction linacs, with several new machines becoming operational and others in the design stages. The performance levels of electron machines have reached 10's of kiloamps of current and will soon reach 10's of MeV's of energy. Acceleration of ion current has been demonstrated, and the study of a 10 GeV heavy ion induction linac for ICF continues. The operating principles of induction linacs are reviewed with the emphasis on design choices which are important for increasing the maximum beam currents

Review of induction linacs

International Nuclear Information System (INIS)

Faltens, A.; Keefe, D.

1982-01-01

There has been a recent upsurge of activity in the field of induction linacs, with several new machines becoming operational and others in the design stages. The performance levels of electron machines have reached 10's of kiloamps of current and will soon reach 10's of MeV's of energy. Acceleration of several kiloamps of ion current has been demonstrated, and the study of a 10 GeV heavy ion induction linac for ICF continues. The operating principles of induction linacs are reviewed with the emphasis on design choices which are important for increasing the maximum beam currents

Analysis of the FEL-RF interaction in recirculating, energy-recovering linacs with an FEL

International Nuclear Information System (INIS)

Merminga, L.; Alexeev, P.; Benson, S.; Bolshakov, A.; Doolittle, L.; Neil, G.

1999-01-01

Recirculating, energy-recovering linacs can be used as driver accelerators for high power FELs. Instabilities which arise from fluctuations of the cavity fields are investigated. Energy changes can cause beam loss on apertures, phase oscillations and optical cavity detuning. These effects in turn cause changes in the laser output power through a time-varying FEL gain function. All three effects change the beam-induced voltage in the cavities and can lead to unstable variations of the accelerating field and output laser power. We have developed a model of the coupled system and solved it both analytically and numerically. It includes the beam-cavity interaction, low level RF feedback, and the electron-photon interaction. The latter includes the FEL gain function in terms of cavity detuning, energy offset, and is valid both in the small signal gain and in the saturated regimes. We have demonstrated that in the limit of small perturbations, the linear theory agrees with the numerical solutions and have performed numerical simulations for the IR FEL presently being commissioned at Jefferson Lab

Analysis of the FEL-RF interaction in recirculating energy-recovering linacs with an FEL

International Nuclear Information System (INIS)

Merminga, Lia; Alexeev, P.; Benson, Steve; Bolshakov, A.; Doolittle, Lawrence; Neil, George

1999-01-01

Recirculating, energy-recovering linacs can be used as driver accelerators for high power FELs. Instabilities which arise from fluctuations of the cavity fields are investigated. Energy changes can cause beam loss on apertures, phase oscillations and optical cavity detuning. These effects in turn cause changes in the laser output power through a time-varying FEL gain function. All three effects change the beam-induced voltage in the cavities and can lead to unstable variations of the accelerating field and output laser power. We have developed a model of the coupled system and solved it both analytically and numerically. It includes the beam-cavity interaction, low level RF feedback, and the electron-photon interaction. The latter includes the FEL gain function in terms of cavity detuning, energy offset, and is valid both in the small signal gain and in the saturated regimes. We have demonstrated that in the limit of small perturbations, the linear theory agrees with the numerical solutions and have performed numerical simulations for the IR FEL presently being commissioned at Jefferson Lab

Analysis of the FEL-RF interaction in recirculating, energy-recovering linacs with an FEL

Energy Technology Data Exchange (ETDEWEB)

Merminga, L. E-mail: merminga@jlab.org; Alexeev, P.; Benson, S.; Bolshakov, A.; Doolittle, L.; Neil, G

1999-06-01

Recirculating, energy-recovering linacs can be used as driver accelerators for high power FELs. Instabilities which arise from fluctuations of the cavity fields are investigated. Energy changes can cause beam loss on apertures, phase oscillations and optical cavity detuning. These effects in turn cause changes in the laser output power through a time-varying FEL gain function. All three effects change the beam-induced voltage in the cavities and can lead to unstable variations of the accelerating field and output laser power. We have developed a model of the coupled system and solved it both analytically and numerically. It includes the beam-cavity interaction, low level RF feedback, and the electron-photon interaction. The latter includes the FEL gain function in terms of cavity detuning, energy offset, and is valid both in the small signal gain and in the saturated regimes. We have demonstrated that in the limit of small perturbations, the linear theory agrees with the numerical solutions and have performed numerical simulations for the IR FEL presently being commissioned at Jefferson Lab.

High average-power induction linacs

International Nuclear Information System (INIS)

Prono, D.S.; Barrett, D.; Bowles, E.; Caporaso, G.J.; Chen, Yu-Jiuan; Clark, J.C.; Coffield, F.; Newton, M.A.; Nexsen, W.; Ravenscroft, D.; Turner, W.C.; Watson, J.A.

1989-01-01

Induction linear accelerators (LIAs) are inherently capable of accelerating several thousand amperes of ∼ 50-ns duration pulses to > 100 MeV. In this paper the authors report progress and status in the areas of duty factor and stray power management. These technologies are vital if LIAs are to attain high average power operation. 13 figs

Particle surface area and bacterial activity in recirculating aquaculture systems

DEFF Research Database (Denmark)

Pedersen, Per Bovbjerg; von Ahnen, Mathis; Fernandes, Paulo

2017-01-01

Suspended particles in recirculating aquaculture systems (RAS) provide surface area that can be colonized by bacteria. More particles accumulate as the intensity of recirculation increases thus potentially increasing the bacterial carrying capacity of the systems. Applying a recent, rapid, culture...... but may provide significant surface area. Hence, the study substantiates that particles in RAS provide surface area supporting bacterial activity, and that particles play a key role in controlling the bacterial carrying capacity at least in less intensive RAS. Applying fast, culture-independent techniques......-independent fluorometric detection method (Bactiquant®) for measuring bacterial activity, the current study explored the relationship between total particle surface area (TSA, derived from the size distribution of particles >5 μm) and bacterial activity in freshwater RAS operated at increasing intensity of recirculation...

Production of cobia in recirculating systems

Science.gov (United States)

Only limited information exists with respect to rearing juvenile cobia Rachycentron canadum to stocker and marketable sizes using recirculating aquaculture systems (RAS). To investigate this topic, two rearing trials were conducted using commercial scale RAS. In Trial 1, juvenile cobia (29 g) we...

Heavy ion induction linacs for fusion

International Nuclear Information System (INIS)

Bangerter, R.O.; Ho, D.D.M.

1991-01-01

In 1976 Denis Keefe proposed the heavy ion induction linac as a driver for inertial confinement fusion (ICF) power plants. Subsequent research has established that heavy ion fusion (HIF) is potentially an attractive energy source and has identified the issues that must be resolved to make HIF a reality. The principal accelerator issues are achieving adequately low transverse and longitudinal emittance and acceptable cost. Results from the single and multiple beam experiments at LBL on transverse emittance are encouraging. A predicted high current longitudinal instability that can affect longitudinal emittance is currently being studied. This paper presents an overview of economics and ICF target requirements and their relationship to accelerator design. It also presents a summary of the status of heavy ion induction linac research. It concludes with a discussion of research plans, including plans for the proposed Induction Linac Systems Experiments (ILSE)

RF-Based Accelerators for HEDP Research

CERN Document Server

Staples, John W; Keller, Roderich; Ostroumov, Peter; Sessler, Andrew M

2005-01-01

Accelerator-driven High-Energy Density Physics experiments require typically 1 nanosecond, 1 microcoulomb pulses of mass 20 ions accelerated to several MeV to produce eV-level excitations in thin targets, the "warm dense matter" regime. Traditionally the province of induction linacs, RF-based acceleration may be a viable alternative with recent breakthroughs in accelerating structures and high-field superconducting solenoids. A reference design for an RF-based accelerator for HEDP research is presented using 15 T solenoids and multiple-gap RF structures configured with either multiple parallel beams (combined at the target) or a single beam and a small stacking ring that accumulates 1 microcoulomb of charge. In either case, the beam is ballistically compressed with an induction linac core providing the necessary energy sweep and injected into a plasma-neutralized drift compression channel resulting in a 1 mm radius beam spot 1 nanosecond long at a thin foil or low-density target.

Optimization of recirculating laminar air flow in operating room air conditioning systems

Directory of Open Access Journals (Sweden)

Enver Yalcin

2016-04-01

Full Text Available The laminar flow air-conditioning system with 100% fresh air is used in almost all operating rooms without discrimination in Turkey. The laminar flow device which is working with 100% fresh air should be absolutely used in Type 1A operating rooms. However, there is not mandatory to use of 100% fresh air for Type 1B defined as places performed simpler operation. Compared with recirculating laminar flow, energy needs of the laminar flow with 100 % fresh air has been emerged about 40% more than re-circulated air flow. Therefore, when a recirculating laminar flow device is operated instead of laminar flow system with 100% fresh air in the Type 1B operating room, annual energy consumption will be reduced. In this study, in an operating room with recirculating laminar flow, optimal conditions have been investigated in order to obtain laminar flow form by analyzing velocity distributions at various supply velocities by using computational fluid dynamics method (CFD.

Mathematical Modeling Of The Acceleration Process In Race-track Microtron

CERN Document Server

Gromov, A M; Vasilev, A A

2004-01-01

The precise calculations of beam dynamics are needed to make choice of optimal design parameters of race-track microtron. As a result, the necessary physical require-ments to the accelerator systems become found. For cal-culation of the magnetic field, POISSON LANL code is used. Acceleration of the beam is investigated with the help of the program of MathCad. Nonlinear distribution of the field in magnets of micro-tron with adjustable reverse field was simulated. The equation of motion of a beam in bending magnets of re-circulation system are found and solved by a numerical method. Trajectories of the beam for all orbits in a micro-tron are received. The recursive equation for calculation of the largest area of injected beam phase and power spreads providing steady acceleration process is written. The acceleration of the beam with maximal phase-energy area through all orbits of microtron was simulated. The velocity of accelerated particles on first orbits dif-fers from velocity of light. The minimal energy ...

The CEBAF accelerator and its physics program

International Nuclear Information System (INIS)

Cardman, L.S.

1993-01-01

The continuous electron beam accelerator facility (CEBAF) consists of a pair of 400 MeV superconducting linacs together with a 5-pass recirculation system and beam switchyard that will permit it to provide three, simultaneous 4 GeV, cw electron beams with a total current of up to 200 μA. The conventional construction for the accelerator and the three experimental end stations is essentially complete. The first linac has been installed in the accelerator tunnel and beam has been accelerated through it; all tests to date have met or exceeded the design specifications. The major components of the experimental equipment for the end stations are under construction. Operation of CEBAF for nuclear physics is scheduled to begin in mid-1994. The facility will support a broad range of nuclear physics research, including topics such as how quarks and gluons are held together in protons and neutrons, the origins of the nuclear force, modifications of nucleons in the nuclear medium, and nuclear structure when nucleons are very close together. The status of the accelerator and its experimental equipment will be presented together with a sampling of experiments planned for the early phases of operation

Recent advances in the development of high average power induction accelerators for industrial and environmental applications

International Nuclear Information System (INIS)

Neau, E.L.

1994-01-01

Short-pulse accelerator technology developed during the early 1960's through the late 1980's is being extended to high average power systems capable of use in industrial and environmental applications. Processes requiring high dose levels and/or high volume throughput will require systems with beam power levels from several hundreds of kilowatts to megawatts. Beam accelerating potentials can range from less than 1 MeV to as much as 10 MeV depending on the type of beam, depth of penetration required, and the density of the product being treated. This paper addresses the present status of a family of high average power systems, with output beam power levels up to 200 kW, now in operation that use saturable core switches to achieve output pulse widths of 50 to 80 nanoseconds. Inductive adders and field emission cathodes are used to generate beams of electrons or x-rays at up to 2.5 MeV over areas of 1000 cm 2 . Similar high average power technology is being used at ≤ 1 MeV to drive repetitive ion beam sources for treatment of material surfaces over 100's of cm 2

Theoretical analysis of recirculation zone and buffer zone in the ADS windowless spallation target

International Nuclear Information System (INIS)

Liu, Jie; Pan, Chang-zhao; Tong, Jian-fei; Lu, Wen-qiang

2015-01-01

Highlights: • Height of recirculation zone is very important in windowless target design. • A theoretical formula for the height is derived based on the Bernoulli equation. • Numerical simulation for the LBE is performed and the height of recirculation zone is also obtained. • The theoretically-derived simulation-predicted recirculation zone heights agree with each other very well and the theoretical derivation is proved to be correct. - Abstract: The thermo-hydraulic analysis including reduction of the height of recirculation zone and stability of the free surface is very important in the design and optimization of ADS windowless spallation targets. In the present study, the Bernoulli equation is used to analyze the entire flow process in the target. Formulae for the height of the recirculation zone and the buffer zone are both obtained explicitly. Furthermore, numerical simulation for the heavy metal lead–bismuth eutectic liquid and vapor with cavitation phase change is also performed, and a novel method to calculate the height of the recirculation zone is put forward. By comparison of the theoretical formulae and numerical results, it is clearly shown that they agree with each other very well, and the heights predicted by the two methods are both determined by their own upstream flow parameters

Maintenance experience on reactor recirculation pumps at Tarapur Atomic Power Station

International Nuclear Information System (INIS)

Singh, A.K.

1995-01-01

Reactor recirculation pumps at Tarapur Atomic Power Station (TAPS) are vertical, single stage centrifugal pumps having mechanical shaft seals and are driven by vertical mounted 3.3 kV, 3 phase, 1500 h.p. electric motors. During these years of operation TAPS has gained enough experience and expertise on the maintenance of reactor recirculation pumps which are dealt in this article. Failure of mechanical shaft seals, damage on pump carbon bearings, motor winding insulation failures and motor shaft damage have been the main areas of concern on recirculation pump. A detailed procedure step by step with component sketches has helped in eliminating errors during shaft seal assembly and installation. Pressure breakdown devices in seal assembly were rebuilt. Additional coolant water injection for shaft seal cooling was provided. These measures have helped in extending the reactor recirculation pump seal life. Pump bearing problems were mainly due to failure of anti-rotation pins and dowel pins of bearing assembly. These pins were redesigned and strengthened. Motor stator winding insulation failures were detected. Stator winding replacement program has been taken up on regular basis to avoid winding insulation failure due to aging. 3 refs., 2 tabs., 7 figs

A recirculating stream aquarium for ecological studies.

Science.gov (United States)

Gordon H. Reeves; Fred H. Everest; Carl E. McLemore

1983-01-01

Investigations of the ecological behavior of fishes often require studies in both natural and artificial stream environments. We describe a large, recirculating stream aquarium and its controls, constructed for ecological studies at the Forestry Sciences Laboratory in Corvallis.

KE basin recirculation/skimmer/IX systems restart acceptance test report

International Nuclear Information System (INIS)

Derosa, D.C.

1996-01-01

The 105 KE Basin Recirculation System and Skimmer Loop have been upgraded to provide the flexibility to run the Ion Exchange Modules on either system to support spent fuel removal for the Spent Nuclear Fuel Project. This Acceptance Test Report Provides the documentation of the leak Testing for the construction work associated with the IXM inlet and outlet piping, places the cartridge filters back in service and provides the functional testing of the IXM's on the recirculation and skimmer systems

Prediction of flow recirculation in a blanket assembly under worst-case natural-convection conditions

International Nuclear Information System (INIS)

Khan, E.U.; Rector, D.R.

1982-01-01

Reactor fuel and blanket assemblies within a Liquid Metal Fast Breeder Reactor (LMFBR) can be subjected to severe radial heat flux gradients. At low-flow conditions, with power-to-flow ratios of nearly the same magnitude as design conditions, buoyancy forces cause flow redistribution to the side of a bundle with the higher heat generation rate. Recirculation of fluid within a rod bundle can occur during a natural convection transient because of the combined effect of flow coastdown and buoyancy-induced redistribution. An important concern is whether recirculation leads to high coolant temperatures. For this reason, the COBRA-WC code was developed with the capability of modeling recirculating flows. Experiments have been conducted in a 2 x 6 rod bundle for flow and power transients to study recirculation in the mixed-convection (forced cooled) and natural-convection regimes. The data base developed was used to validate the recirculation module in the COBRA-WC code. COBRA-WC code calculations were made to predict flow and temperature distributions in a typical LMFBR blanket assembly for the worst-case, natural-circulation transient

Define of internal recirculation coefficient for biological wastewater treatment in anoxic and aerobic bioreactors

Science.gov (United States)

Rossinskyi, Volodymyr

2018-02-01

The biological wastewater treatment technologies in anoxic and aerobic bioreactors with recycle of sludge mixture are used for the effective removal of organic compounds from wastewater. The change rate of sludge mixture recirculation between bioreactors leads to a change and redistribution of concentrations of organic compounds in sludge mixture in bioreactors and change hydrodynamic regimes in bioreactors. Determination of the coefficient of internal recirculation of sludge mixture between bioreactors is important for the choice of technological parameters of biological treatment (wastewater treatment duration in anoxic and aerobic bioreactors, flow capacity of recirculation pumps). Determination of the coefficient of internal recirculation of sludge mixture requires integrated consideration of hydrodynamic parameter (flow rate), kinetic parameter (rate of oxidation of organic compounds) and physical-chemical parameter of wastewater (concentration of organic compounds). The conducted numerical experiment from the proposed mathematical equations allowed to obtain analytical dependences of the coefficient of internal recirculation sludge mixture between bioreactors on the concentration of organic compounds in wastewater, the duration of wastewater treatment in bioreactors.

Multi-point optimization of recirculation flow type casing treatment in centrifugal compressors

Science.gov (United States)

Tun, Min Thaw; Sakaguchi, Daisaku

2016-06-01

High-pressure ratio and wide operating range are highly required for a turbocharger in diesel engines. A recirculation flow type casing treatment is effective for flow range enhancement of centrifugal compressors. Two ring grooves on a suction pipe and a shroud casing wall are connected by means of an annular passage and stable recirculation flow is formed at small flow rates from the downstream groove toward the upstream groove through the annular bypass. The shape of baseline recirculation flow type casing is modified and optimized by using a multi-point optimization code with a metamodel assisted evolutionary algorithm embedding a commercial CFD code CFX from ANSYS. The numerical optimization results give the optimized design of casing with improving adiabatic efficiency in wide operating flow rate range. Sensitivity analysis of design parameters as a function of efficiency has been performed. It is found that the optimized casing design provides optimized recirculation flow rate, in which an increment of entropy rise is minimized at grooves and passages of the rotating impeller.

Inductive voltage adder (IVA) for submillimeter radius electron beam

International Nuclear Information System (INIS)

Mazarakis, M.G.; Poukey, J.W.; Maenchen, J.E.

1996-01-01

The authors have already demonstrated the utility of inductive voltage adder accelerators for production of small-size electron beams. In this approach, the inductive voltage adder drives a magnetically immersed foilless diode to produce high-energy (10--20 MeV), high-brightness pencil electron beams. This concept was first demonstrated with the successful experiments which converted the linear induction accelerator RADLAC II into an IVA fitted with a small 1-cm radius cathode magnetically immersed foilless diode (RADLAC II/SMILE). They present here first validations of extending this idea to mm-scale electron beams using the SABRE and HERMES-III inductive voltage adders as test beds. The SABRE experiments are already completed and have produced 30-kA, 9-MeV electron beams with envelope diameter of 1.5-mm FWHM. The HERMES-III experiments are currently underway

Heavy-ion fusion accelerator research, 1989

International Nuclear Information System (INIS)

1990-06-01

This report discusses the following topics on heavy-ion fusion accelerator research: MBE-4: the induction-linac approach; transverse beam dynamics and current amplification; scaling up the results; through ILSE to a driver; ion-source and injector development; and accelerator component research and development

Pelletron-based MeV-range electron beam recirculation

CERN Document Server

Crawford, A C; Sharapa, A N; Shemyakin, A

1999-01-01

In this paper we describe the successful recirculation of a DC electron beam at energies 1-1.5 MeV and currents up to 0.7 A with typical relative losses of 5-20x10 sup - sup 6. Currents of 200 mA were maintained for periods of up to five hours without a single breakdown. We found that the aperture-limiting diaphragm in the gun anode significantly increased the stability of the recirculation. We also found that the stability depended strongly on vacuum pressure in the beamline. The performance of the collector with transverse magnetic fields was found to be adequate for beam currents up to 0.6 A, which is in agreement with our low-energy bench test results. (author)

A portable gas recirculation unit for gaseous detectors

Science.gov (United States)

Guida, R.; Mandelli, B.

2017-10-01

The use of greenhouse gases (usually C2H2F4, CF4 and SF6) is sometimes necessary to achieve the required performance for some gaseous detectors. The consumption of these gases in the LHC systems is reduced by recycling the gas mixture thanks to a complex gas recirculation system. Beyond greenhouse gas consumption due to LHC systems, a considerable contribution is generated by setups used for LHC detector upgrade projects, R&D activities, detector quality assurance or longevity tests. In order to minimise this emission, a new flexible and portable gas recirculation unit has been developed. Thanks to its low price, flexibility and user-friendly operation it can be easily adapted for the different types of detector systems and set-ups.

Seismic proving test of BWR primary loop recirculation system

International Nuclear Information System (INIS)

Sato, H.; Shigeta, M.; Karasawa, Y.

1987-01-01

The seismic proving test of BWR Primary Loop Recirculation system is the second test to use the large-scale, high-performance vibration table of Tadotsu Engineering Laboratory. The purpose of this test is to prove the seismic reliability of the primary loop recirculation system (PLR), one of the most important safety components in the BWR nuclear plants, and also to confirm the adequacy of seismic analysis method used in the current seismic design. To achieve the purpose, the test was conducted under conditions and scale as near as possible to actual systems. The strength proving test was carried out with the test model mounted on the vibration table in consideration of basic design earthquake ground motions and other conditions to confirm the soundness of structure and the strength against earthquakes. Detailed analysis and analytic evaluation of the data obtained from the test was conducted to confirm the adequacy of the seismic analysis method and earthquake response analysis method used in the current seismic design. Then, on the basis of the results obtained, the seismic safety and reliability of BWR primary loop recirculation of the actual plants was fully evaluated

Energy stability in recirculating, energy-recovering linacs in the presence of a FEL

International Nuclear Information System (INIS)

Merminga, L.; Bisognano, J.; Delayen, J.R.

1996-01-01

Recirculating, energy-recovering linacs can be used as driver accelerators for high power FELs (free electron lasers). Instabilities which arise from fluctuations of the cavity fields are investigated. Energy changes can cause beam loss on apertures, or, when coupled to M 56 , phase oscillations. Both effects change the beam induced voltage in the cavities and can lead to unstable variations of the accelerating field. An analytical model which includes amplitude and phase feedback, has been developed to study the stability of the system for small perturbations from equilibrium. The interaction of the electron beam with the FEL is a major perturbation which affects both the stability of the system and development of startup and recovery scenarios. To simulate the system's response to such large parameter variations, a numerical model of the beam-cavity interaction has been developed which includes low level rf feedback, phase oscillations and beam loss instabilities and the FEL interaction. Agreement between the numerical model and the linear theory has been demonstrated in the limit of small perturbations. In addition, the model has been benchmarked against experimental data obtained during CEBAF's high current operation. Numerical simulations have been performed for the high power IR DEMO approved for construction at CEBAF

Automation of water supply and recirculation-filtration of water at a swimming pool using Zelio PLC

Science.gov (United States)

Diniş, C. M.; Popa, G. N.; Iagăr, A.

2018-01-01

The paper proposes the use of the Zelio PLC for the automation of the water supply and recirculation-filtration system of a swimming pool. To do this, the Zelio SR3B261BD - 24V DC with 10 digital inputs (24V DC) and 10 digital outputs (relay contacts) was used. The proposed application makes the control of the water supply pumps and the water recirculation-filtration from a swimming pool. The recirculation-filtration systems for pools and swimming pools are designed to ensure water cleaning and recirculation to achieve optimum quality and lasting service life. The water filtration process is one of the important steps in water treatment in polls and swimming pools. It consists in recirculation of the entire volume of water and begins by absorbing the water in the pool by means of a pump followed by the passing of water through the filter, disinfectant and pH dosing, and reintroducing the water back into the pool or swimming pool through the discharge holes. Filters must to work 24 hours a day to remove pollutants from pools or swimming pools users. Filtration removes suspension particles with different origins. All newly built pools and swimming pools must be fitted with water recirculation systems, and existing ones will be equipped with water recirculation and water treatment systems.

Impact of capillary rise and recirculation on simulated crop yields

Science.gov (United States)

Kroes, Joop; Supit, Iwan; van Dam, Jos; van Walsum, Paul; Mulder, Martin

2018-05-01

Upward soil water flow is a vital supply of water to crops. The purpose of this study is to determine if upward flow and recirculated percolation water can be quantified separately, and to determine the contribution of capillary rise and recirculated water to crop yield and groundwater recharge. Therefore, we performed impact analyses of various soil water flow regimes on grass, maize and potato yields in the Dutch delta. Flow regimes are characterized by soil composition and groundwater depth and derived from a national soil database. The intermittent occurrence of upward flow and its influence on crop growth are simulated with the combined SWAP-WOFOST model using various boundary conditions. Case studies and model experiments are used to illustrate the impact of upward flow on yield and crop growth. This impact is clearly present in situations with relatively shallow groundwater levels (85 % of the Netherlands), where capillary rise is a well-known source of upward flow; but also in free-draining situations the impact of upward flow is considerable. In the latter case recirculated percolation water is the flow source. To make this impact explicit we implemented a synthetic modelling option that stops upward flow from reaching the root zone, without inhibiting percolation. Such a hypothetically moisture-stressed situation compared to a natural one in the presence of shallow groundwater shows mean yield reductions for grassland, maize and potatoes of respectively 26, 3 and 14 % or respectively about 3.7, 0.3 and 1.5 t dry matter per hectare. About half of the withheld water behind these yield effects comes from recirculated percolation water as occurs in free-drainage conditions and the other half comes from increased upward capillary rise. Soil water and crop growth modelling should consider both capillary rise from groundwater and recirculation of percolation water as this improves the accuracy of yield simulations. This also improves the accuracy of the

Accelerator requirments for strategic defense

International Nuclear Information System (INIS)

Gullickson, R.L.

1987-01-01

The authors discuss how directed energy applications require accelerators with high brightness and large gradients to minimize size and weight for space systems. Several major directed energy applications are based upon accelerator technology. The radio-frequency linear accelerator is the basis for both space-based neutral particle beam (NPB) and free electron laser (FEL) devices. The high peak current of the induction linac has made it a leading candidate for ground based free electron laser applications

Preliminary design of a 10 MV ion accelerator

International Nuclear Information System (INIS)

Fessenden, T.J.; Celata, C.M.; Faltens, A.

1986-06-01

At the low energy end of an induction linac HIF driver the beam current is limited by our ability to control space charge by a focusing system. As a consequence, HIF induction accelerator designs feature simultaneous acceleration of many beams in parallel within a single accelerator structure. As the speed of the beams increase, the focusing system changes from electrostatic to magnetic quadrupoles with a corresponding increase in the maximum allowable current. At that point the beams are merged thereby decreasing the cost of the subsequent accelerator structure. The LBL group is developing an experiment to study the physics of merging and of focusing ion beams. In the design, parallel beams of ions (C + , Al + , or Al ++ ) are accelerated to several MV and merged transversely. The merged beams are then further accelerated and the growth in transverse and longitudinal emittance is determined for comparison with theory. The apparatus will then be used to study the problems associated with focusing ion beams to a small spot. Details of the accelerator design and considerations of the physics of combining beams are presented

Effect of gas recirculation in a pilot-scale cow-dung digester

Energy Technology Data Exchange (ETDEWEB)

Pathak, B N; Kulkarni, D N; Dave, J M; Mohanrao, G J

1965-01-01

Laboratory experiments showed that if, during anaerobic digestion of cow manure, the contents of the digestion vessel are mixed by recirculating gas, nearly twice as much gas is produced, and there is less variation in the temperature of the digesting liquor, the pH value, the carbon-dioxide content of the gas, and the reduction in volatile matter. Results of experiments during which gas was recirculated for periods ranging from 0 to 4 hours are tabulated.

Simultaneous water desalination and electricity generation in a microbial desalination cell with electrolyte recirculation for pH control

KAUST Repository

Qu, Youpeng

2012-02-01

A recirculation microbial desalination cell (rMDC) was designed and operated to allow recirculation of solutions between the anode and cathode chambers. This recirculation avoided pH imbalances that could inhibit bacterial metabolism. The maximum power density was 931±29mW/m 2 with a 50mM phosphate buffer solution (PBS) and 776±30mW/m 2 with 25mM PBS. These power densities were higher than those obtained without recirculation of 698±10mW/m 2 (50mM PBS) and 508±11mW/m 2 (25mM PBS). The salt solution (20g/L NaCl) was reduced in salinity by 34±1% (50mM) and 37±2% (25mM) with recirculation (rMDC), and by 39±1% (50mM) and 25±3% (25mM) without recirculation (MDC). These results show that electrolyte recirculation using an rMDC is an effective method to increase power and achieve efficient desalination by eliminating pH imbalances. © 2011 Elsevier Ltd.

Control-oriented modeling of two-stroke diesel engines with exhaust gas recirculation for marine applications

OpenAIRE

Llamas, Xavier; Eriksson, Lars

2018-01-01

Large marine two-stroke diesel engines are widely used as propulsion systems for shipping worldwide and are facing stricter NOx emission limits. Exhaust gas recirculation is introduced to these engines to reduce the produced combustion NOx to the allowed levels. Since the current number of engines built with exhaust gas recirculation is low and engine testing is very expensive, a powerful alternative for developing exhaust gas recirculation controllers for such engines is to use control-orien...

Evaluation of a rainbow trout (Oncorhynchus mikyss culture water recirculating system

Directory of Open Access Journals (Sweden)

Iván Sánchez O.

2014-09-01

Full Text Available Objective. To evaluate a water recirculation system for rainbow trout fish cultures at the recirculating laboratory of the Aquaculture Engineering Production Program of University of Nariño. Materials and Methods. 324 rainbow trout (Oncorhynchus mikyss fries were cultured in 12 plastic tanks with a capacity of 250 L in an aquaculture recirculating system the treatment system of which was made up by a conventional sedimentation tank, a fixed stand upflow biofilter with recycled PVC tube pieces and a natural degassing system; the sedimentation unit effluent was pumped up to a reservoir tank using a 2 HP centrifugal pump after being subject to gravity through the biofilter and to be then distributed to the 12 culture units to which a constant amount of air from a blower was injected. Results. The water treatment system removed 31% of total suspended solids, 9.5% of total ammonia nitrogen, and increased dissolved oxygen to the final effluent in 6.5%. An increase of 305% in biomass was calculated during 75 days, the mortality percentage registered throughout the study period was 4.9%. Conclusions. The water treatment system maintained the physicochemical water quality parameters within the values recommended for the species. The increase in weight and size, food conversion, mortality and biomass production reported normal values for rainbow trout fish culture in recirculating systems.

A concentrated solar cavity absorber with direct heat transfer through recirculating metallic particles

Energy Technology Data Exchange (ETDEWEB)

Sarker, M. R. I., E-mail: islamrabiul@yahoo.com; Saha, Manabendra, E-mail: manabendra.saha@adelaide.edu.au, E-mail: manab04me@gmail.com; Beg, R. A. [Department of Mechanical Engineering, Rajshahi University of Engineering and Technology, Rajshahi-6204 (Bangladesh)

2016-07-12

A recirculating flow solar particle cavity absorber (receiver) is modeled to investigate the flow behavior and heat transfer characteristics of a novel developing concept. It features a continuous recirculating flow of non-reacting metallic particles (black silicon carbide) with air which are used as a thermal enhancement medium. The aim of the present study is to numerically investigate the thermal behavior and flow characteristics of the proposed concept. The proposed solar particle receiver is modeled using two phase discrete particle model (DPM), RNG k-flow model and discrete ordinate (DO) radiation model. Numerical analysis is carried out considering a solar receiver with only air and the mixture of non-reacting particles and air as a heat transfer as well as heat carrying medium. The parametric investigation is conducted considering the incident solar flux on the receiver aperture and changing air flow rate and recirculation rate inside the receiver. A stand-alone feature of the recirculating flow solar particle receiver concept is that the particles are directly exposed to concentrated solar radiation monotonously through recirculating flow inside the receiver and results in efficient irradiation absorption and convective heat transfer to air that help to achieve high temperature air and consequently increase in thermal efficiency. This paper presents, results from the developed concept and highlights its flow behavior and potential to enhance the heat transfer from metallic particles to air by maximizing heat carrying capacity of the heat transfer medium. The imposed milestones for the present system will be helpful to understand the radiation absorption mechanism of the particles in a recirculating flow based receiver, the thermal transport between the particles, the air and the cavity, and the fluid dynamics of the air and particle in the cavity.

Berkeley research program on ion-induction linacs for inertial fusion

International Nuclear Information System (INIS)

Keefe, D.; Rosenblum, S.S.

1982-03-01

The following areas of research are described: (1) driver studies, (2) induction linac technology, (3) core materials, (4) insulators, (5) modulator-switches and pulse forming network, (6) induction linac accelerators and prototype modules, and (7) a high-temperature experiment

Investigation of flashing de-aeration with and without recirculation

International Nuclear Information System (INIS)

Kjellstroem, B.; Toecksberg, B.

1977-06-01

A series of experiments with flashing de-areation has been carried out at the institute of Thermal Energytechnology of the Royal Institute of Technology in Stockholm. The results of the experiments with flashing de-areation without recirculation of the condensate show very low contents of dissolved oxygen in the de-aerated water. The results indicate that the de-aeration process is independent of the pressure. De-aeration efficiencies over 99 percent were measured. The continued experiments with recirculation of the condensate show a considerably deteriorated de-aeration performance together with a marked pressure dependency. A simple theoretical model has been formulated which explains these results. Comparisons between the experimental data and calculations with this model indicate that a conservative estimation of the oxygen content of the outgoing water can be obtained if the oxygen content of the recirculated condensate is calculated for the partial pressure of noncondensible gases equal to the total pressure in the condensor. It seems also possible to estimate a lower limit for the oxygen content of the outgoing water. The range of oxygen content between those limits is about a factor of 10 for the conditions investigated. Further studies of the uptake of oxygen during condensation seem necessary if a more accurate prediction is desired

Dynamics and acceleration in linear structures

International Nuclear Information System (INIS)

Le Duff, J.

1985-06-01

Basic methods of linear acceleration are reviewed. Both cases of non relativistic and ultra relativistic particles are considered. Induction linac, radiofrequency quadrupole are mentioned. Fundamental parameters of accelerating structures are recalled; they are transit time factor, shunt impedance, quality factor and stored energy, phase velocity and group velocity, filling time, space harmonics in loaded waveguides. Energy gain in linear accelerating structures is considered through standing wave structures and travelling wave structures. Then particle dynamics in linear accelerators is studied: longitudinal motion, transverse motion and dynamics in RFQ

Thermodynamic Model for Updraft Gasifier with External Recirculation of Pyrolysis Gas

Directory of Open Access Journals (Sweden)

Fajri Vidian

2016-01-01

Full Text Available Most of the thermodynamic modeling of gasification for updraft gasifier uses one process of decomposition (decomposition of fuel. In the present study, a thermodynamic model which uses two processes of decomposition (decomposition of fuel and char is used. The model is implemented in modification of updraft gasifier with external recirculation of pyrolysis gas to the combustion zone and the gas flowing out from the side stream (reduction zone in the updraft gasifier. The goal of the model obtains the influences of amount of recirculation pyrolysis gas fraction to combustion zone on combustible gas and tar. The significant results of modification updraft are that the increases amount of recirculation of pyrolysis gas will increase the composition of H2 and reduce the composition of tar; then the composition of CO and CH4 is dependent on equivalence ratio. The results of the model for combustible gas composition are compared with previous study.

Analysis of an induction linac driver system for inertial fusion

International Nuclear Information System (INIS)

Hovingh, J.; Brady, V.O.; Faltens, A.; Keefe, D.; Lee, E.P.

1987-07-01

A linear induction accelerator that produces a beam of energetic (5 to 20 GeV) heavy (130 to 210 amu) ions is a prime candidate as a driver for inertial fusion. Continuing developments in sources for ions with charge state greater than unity allow a potentially large reduction in the driver cost and an increase in the driver efficiency. The use of high undepressed tunes (σ 0 ≅ 85 0 ) and low depressed tunes (σ ≅ 8.5 0 ) also contributes to a potentially large reduction in the driver cost. The efficiency and cost of the induction linac system are discussed as a function of output energy and pulse repetition frequency for several ion masses and charge states. The cost optimization code LIACEP, including accelerating module alternatives, transport modules, and scaling laws, is presented. Items with large cost-leverage are identified as a guide to future research activities and development of technology that can yield substantial reductions in the accelerator system cost and improvement in the accelerator system efficiency. Finally, a cost-effective strategy using heavy ion induction linacs in a development scenario for inertial fusion is presented. 34 refs., 6 figs., 7 tabs

A new linear induction voltage adder approach to radiography

International Nuclear Information System (INIS)

Mazarakis, M.G.; Poukey, J.W.; Frost, C.A.; Johnson, D.L.; Shope, S.L.; Halbleib, J.A.; Prestwich, K.R.; Turman, B.N.; Smith, I.

1992-01-01

At present, two types of accelerators are being utilized for x-ray radiography: first a linear RF or induction accelerator with multiple accelerating gaps and beam vacuum magnetic transport systems; and second, single gap pulse-power devices with a high voltage Blumlein pulse forming line. The authors present a conceptual design of a new type of linear induction accelerator that can bridge the gap between the two devices. It can produce 30--50-kA electron currents small diameter (∼ 1 mm) and high energy (12--20-MV) beams. There is no beam drifting through the device. The voltage addition of the accelerating gaps occurs at the central self-magnetically insulated cathode electrode. The electron beam is created at the high voltage end in a single gap diode. A magnetically-immersed foilless diode can produce high quality 0.5 mm radius 30--50 kA beams. A short 100--200-kG small bore solenoidal coil is required to maintain the beam radius during transport from the cathode tips to the x-ray converter target, 50--70 cm downstream. The idea of very high impedance MITL voltage adder accelerators was first tested with RADLAC II/SMILE experiments where 12--14-MV, 50-kA 1 cm radius beams were produced with 2--3 mm annulus thickness. A 12.5 m eight-stage voltage adder was utilized, coupled to a 20 kG magnetically immersed foilless diode. In addition the magnetically-immersed foilless diodes with very thin (mm diameter) cathode tips were investigated in experiments with the IBEX accelerator. As an example of this new accelerator technology the authors present the following point design for a 16-MV, 50-kA accelerator producing 1-mm diameter electron beams. The design is based on a cavity fed MITL voltage adder which performs the series addition of the voltage pulses from 16 identical inductively-isolated cavity feed systems. Each cavity is a structure that is driven by one 14 ohm pulse-forming line, providing a 1 MV voltage pulse to the accelerating gap

Feasibility Study of Moderately Accelerated Intensity-Modulated Radiotherapy Plus Concurrent Weekly Cisplatin After Induction Chemotherapy in Locally Advanced Head-and Neck Cancer

International Nuclear Information System (INIS)

Morganti, Alessio G.; Mignogna, Samantha; Deodato, Francesco; Massaccesi, Mariangela; Cilla, Savino; Calista, Franco; Serafini, Giovanni; Digesu, Cinzia; Macchia, Gabriella; Picardi, Vincenzo; Caravatta, Luciana; Di Lullo, Liberato; Giglio, Gianfranco; Sallustio, Giuseppina; Piermattei, Angelo

2011-01-01

Purpose: To evaluate the feasibility and efficacy of moderately accelerated intensity-modulated radiation therapy (IMRT) along with weekly cisplatin, after induction chemotherapy, in patients with locally advanced unresectable head and neck cancer (HNC). Methods and Materials: Patients with Stage III or IV locally advanced HNC, without progressive disease after three courses of induction chemotherapy, received concurrent chemo-IMRT (weekly cisplatin 30 mg/m 2 plus simultaneous integrated boost IMRT). A total of 67.5 Gy in 30 fractions were delivered to primary tumor and involved nodes, 60 Gy in 30 fractions to high-risk nodal areas, and 55.5 Gy in 30 fractions to low-risk nodal areas. Results: In all, 36 patients (median age, 56 years) with International Union Against Cancer (UICC) Stage III (n = 5) and IV (n = 31) were included. Of the 36 patients, 17 had received CF (cisplatin and 5-fluorouracil (CF) and 19 had received docetaxel cisplatin and 5-fluorouracil (DCF). During concurrent chemoradiation, 11 of 36 patients (30.5%) experienced Grade III mucositis (CF, 47%; DCF, 15%; p < 0.04). Grade III pharyngeal-esophageal toxicity was observed in 5 of 19 patients (26.3%; CF, 0.0%; DCF, 26.3%; p = 0.02). Two patients died of complications (5.5%). After chemoradiation, the complete response rate was 63.8%. Two-year local control was 88.7%. Two-year progression free survival and overall survival were 74.5% and 60.9%, respectively. Conclusions: In our experience, a moderately accelerated chemo-IMRT was feasible after induction chemotherapy. However, a noteworthy early death rate of 5.5% was observed. Intensive supportive care strategies should be defined to better manage radiation-induced toxic effects. Longer follow-up is required to determine the incidence of late radiation toxicities and tumor control rates.

IC ENGINE SUPERCHARGING AND EXHAUST GAS RECIRCULATION USING JET COMPRESSOR

Directory of Open Access Journals (Sweden)

Adhimoulame Kalaisselvane

2010-01-01

Full Text Available Supercharging is a process which is used to improve the performance of an engine by increasing the specific power output whereas exhaust gas recirculation reduces the NOx produced by engine because of supercharging. In a conventional engine, supercharger functions as a compressor for the forced induction of the charge taking mechanical power from the engine crankshaft. In this study, supercharging is achieved using a jet compressor. In the jet compressor, the exhaust gas is used as the motive stream and the atmospheric air as the propelled stream. When high pressure motive stream from the engine exhaust is expanded in the nozzle, a low pressure is created at the nozzle exit. Due to this low pressure, atmospheric air is sucked into the expansion chamber of the compressor, where it is mixed and pressurized with the motive stream. The pressure of the mixed stream is further increased in the diverging section of the jet compressor. A percentage volume of the pressurized air mixture is then inducted back into the engine as supercharged air and the balance is let out as exhaust. This process not only saves the mechanical power required for supercharging but also dilutes the constituents of the engine exhaust gas thereby reducing the emission and the noise level generated from the engine exhaust. The geometrical design parameters of the jet compressor were obtained by solving the governing equations using the method of constant rate of momentum change. Using the theoretical design parameters of the jet compressor, a computational fluid dinamics analysis using FLUENT software was made to evaluate the performance of the jet compressor for the application of supercharging an IC engine. This evaluation turned out to be an efficient diagnostic tool for determining performance optimization and design of the jet compressor. A jet compressor was also fabricated for the application of supercharging and its performance was studied.

Dedicated exhaust gas recirculation control systems and methods

Science.gov (United States)

Sczomak, David P.; Narayanaswamy, Kushal; Keating, Edward J.

2018-05-01

An engine control system of a vehicle includes a fuel control module that controls fuel injection of a first cylinder of an engine based on a first target air/fuel ratio that is fuel lean relative to a stoichiometric air/fuel ratio and that controls fuel injection of a second cylinder of the engine based on a second target air/fuel ratio that is fuel rich relative to stoichiometry. The first cylinder outputs exhaust to a first three way catalyst (TWC), and the second cylinder outputs exhaust to an exhaust gas recirculation (EGR) valve. An EGR control module controls opening of the EGR valve to: (i) a second TWC that reacts with nitrogen oxides (NOx) in the exhaust and outputs ammonia to a selective catalytic reduction (SCR) catalyst; and (ii) a conduit that recirculates exhaust back to an intake system of the engine.

Daily micro particle distribution of an experimental recirculating aquaculture system – A case study

DEFF Research Database (Denmark)

Fernandes, Paulo; Pedersen, Lars-Flemming; Pedersen, Per Bovbjerg

2014-01-01

The particle size distribution (PSD) in a recirculating aquaculture system (RAS) was investigated duringa 24-h cycle. PSD was analyzed in water sampled at several locations in a recirculation loop containing a60-m drum filter, a submerged fixed-bed biofilter and a trickling filter.In relation...

Mutation induction in spores of Bacillus subtilis by accelerated very heavy ions

International Nuclear Information System (INIS)

Baltschukat, K.; Horneck, G.; Buecker, H.; Facius, R.; Schaefer, M.

1986-01-01

Mutation induction (resistance to sodium azide) in spores of Bacillus subtilis was investigated after irradiation with heavy ions from Neon to Uranium with specific particle energies between 0.17 and 18.6 MeV/u. A strong dependence of the mutation induction cross section on particle charge and energy was observed. From the results it was concluded that mutation induction in bacterial spores by very heavy ions is mainly caused by secondary electrons. (orig.)

Anaerobic degradation of dairy wastewater in intermittent UASB reactors: influence of effluent recirculation.

Science.gov (United States)

Couras, C S; Louros, V L; Gameiro, T; Alves, N; Silva, A; Capela, M I; Arroja, L M; Nadais, H

2015-01-01

This work studied the influence of effluent recirculation upon the kinetics of anaerobic degradation of dairy wastewater in the feedless phase of intermittent upflow anaerobic sludge bed (UASB) reactors. Several laboratory-scale tests were performed with different organic loads in closed circuit UASB reactors inoculated with adapted flocculent sludge. The data obtained were used for determination of specific substrate removal rates and specific methane production rates, and adjusted to kinetic models. A high initial substrate removal was observed in all tests due to adsorption of organic matter onto the anaerobic biomass which was not accompanied by biological substrate degradation as measured by methane production. Initial methane production rate was about 45% of initial soluble and colloidal substrate removal rate. This discrepancy between methane production rate and substrate removal rate was observed mainly on the first day of all experiments and was attenuated on the second day, suggesting that the feedless period of intermittent UASB reactors treating dairy wastewater should be longer than one day. Effluent recirculation expressively raised the rate of removal of soluble and colloidal substrate and methane productivity, as compared with results for similar assays in batch reactors without recirculation. The observed bed expansion was due to the biogas production and the application of effluent recirculation led to a sludge bed contraction after all the substrates were degraded. The settleability of the anaerobic sludge improved by the introduction of effluent recirculation this effect being more pronounced for the higher loads.

Induction Linac Systems Experiments for heavy ion fusion

International Nuclear Information System (INIS)

Herrmannsfeldt, W.B.; Bangerter, R.O.

1994-06-01

The Lawrence Berkeley Laboratory and the Lawrence Livermore National Laboratory propose to build at LBL the Induction Linac Systems Experiments (ILSE), the next logical step toward the eventual goal of a heavy ion induction accelerator powerful enough to implode or drive inertial confinement fusion targets. Though much smaller than a driver, ILSE will be at full driver scale in several important parameters. Nearly all accelerator components and beam manipulations required for a driver will be tested. It is expected that ILSE will be built in stages as funds and technical progress allow. The first stage, called Elise will include all of the electrostatic quadrupole focused parts of ILSE

Proposed inductive voltage adder based accelerator concepts for the second axis of DARHT

International Nuclear Information System (INIS)

Smith, D.L.; Johnson, D.L.; Boyes, J.D.

1997-01-01

As participants in the Technology Options Study for the second axis of the Dual Axis Radiographic HydroTest (DARHT) facility located at Los Alamos National Laboratories, the authors have considered several accelerator concepts based on the Inductive Voltage Adder (IVA) technology that is being used successfully at Sandia on the SABRE and HERMES-III facilities. The challenging accelerator design requirements for the IVA approach include: ≥12-MeV beam energy; ∼60-ns electrical pulse width; ≤40-kA electron beam current; ∼1-mm diameter e-beam; four pulses on the same axis or as close as possible to that axis; and an architecture that fits within the existing building envelope. To satisfy these requirements the IVA concepts take a modular approach. The basic idea is built upon a conservative design for eight ferromagnetically isolated 2-MV cavities that are driven by two 3 to 4-Ω water dielectric pulse forming lines (PFLs) synchronized with laser triggered gas switches. The 100-Ω vacuum magnetically insulated transmission line (MITL) would taper to a needle cathode that produces the electron beam(s). After considering many concepts the authors narrowed their study to the following options: (A) Four independent single pulse drivers powering four single pulse diodes; (B) Four series adders with interleaved cavities feeding a common MITL and diode; (C) Four stages of series PFLs, isolated from each other by triggered spark gap switches, with single-point feeds to a common adder, MITL, and diode; and (D) Isolated PFLs with multiple-feeds to a common adder using spark gap switches in combination with saturable magnetic cores to isolate the non-energized lines. The authors will discuss these options in greater detail identifying the challenges and risks associated with each

Charged particle accelerators for inertial fusion energy

International Nuclear Information System (INIS)

Humphries, S. Jr.

1991-01-01

The long history of successful commercial applications of charged-particle accelerators is largely a result of initiative by private industry. The Department of Energy views accelerators mainly as support equipment for particle physicists rather than components of an energy generation program. In FY 91, the DOE spent over 850 M$ on building and supporting accelerators for physics research versus 5 M$ on induction accelerators for fusion energy. The author believes this emphasis is skewed. One must address problems of long-term energy sources to preserve the possibility of basic research by future generations. In this paper, the author reviews the rationale for accelerators as inertial fusion drivers, emphasizing that these devices provide a viable path of fusion energy from viewpoints of both physics and engineering. In this paper, he covered the full range of accelerator fusion applications. Because of space limitations, this paper concentrates on induction linacs for ICF, an approach singled out in recent reports by the National Academy of Sciences and the Fusion Policy Advisory Committee as a promising path to long-term fusion power production. Review papers by Cook, Leung, Franzke, Hofmann and Reiser in these proceedings give details on light ion fusion and RF accelerator studies

Impact of capillary rise and recirculation on simulated crop yields

Directory of Open Access Journals (Sweden)

J. Kroes

2018-05-01

Full Text Available Upward soil water flow is a vital supply of water to crops. The purpose of this study is to determine if upward flow and recirculated percolation water can be quantified separately, and to determine the contribution of capillary rise and recirculated water to crop yield and groundwater recharge. Therefore, we performed impact analyses of various soil water flow regimes on grass, maize and potato yields in the Dutch delta. Flow regimes are characterized by soil composition and groundwater depth and derived from a national soil database. The intermittent occurrence of upward flow and its influence on crop growth are simulated with the combined SWAP-WOFOST model using various boundary conditions. Case studies and model experiments are used to illustrate the impact of upward flow on yield and crop growth. This impact is clearly present in situations with relatively shallow groundwater levels (85 % of the Netherlands, where capillary rise is a well-known source of upward flow; but also in free-draining situations the impact of upward flow is considerable. In the latter case recirculated percolation water is the flow source. To make this impact explicit we implemented a synthetic modelling option that stops upward flow from reaching the root zone, without inhibiting percolation. Such a hypothetically moisture-stressed situation compared to a natural one in the presence of shallow groundwater shows mean yield reductions for grassland, maize and potatoes of respectively 26, 3 and 14 % or respectively about 3.7, 0.3 and 1.5 t dry matter per hectare. About half of the withheld water behind these yield effects comes from recirculated percolation water as occurs in free-drainage conditions and the other half comes from increased upward capillary rise. Soil water and crop growth modelling should consider both capillary rise from groundwater and recirculation of percolation water as this improves the accuracy of yield simulations. This also improves the

Effects of recirculation in a three-tank pilot-scale system for pharmaceutical removal with powdered activated carbon.

Science.gov (United States)

Kårelid, Victor; Larsson, Gen; Björlenius, Berndt

2017-05-15

The removal of pharmaceutically active compounds by powdered activated carbon (PAC) in municipal wastewater is a promising solution to the problem of polluted recipient waters. Today, an efficient design strategy is however lacking with regard to high-level overall, and specific, substance removal in the large scale. The performance of PAC-based removal of pharmaceuticals was studied in pilot-scale with respect to the critical parameters; contact time and PAC dose using one PAC product selected by screening in bench-scale. The goal was a minimum of 95% removal of the pharmaceuticals present in the evaluated municipal wastewater. A set of 21 pharmaceuticals was selected from an initial 100 due to their high occurrence in the effluent water of two selected wastewater treatment plants (WWTPs) in Sweden, whereof candidates discussed for future EU regulation directives were included. By using recirculation of PAC over a treatment system using three sequential contact tanks, a combination of the benefits of powdered and granular carbon performance was achieved. The treatment system was designed so that recirculation could be introduced to any of the three tanks to investigate the effect of recirculation on the adsorption performance. This was compared to use of the setup, but without recirculation. A higher degree of pharmaceutical removal was achieved in all recirculation setups, both overall and with respect to specific substances, as compared to without recirculation. Recirculation was tested with nominal contact times of 30, 60 and 120 min and the goal of 95% removal could be achieved already at the shortest contact times at a PAC dose of 10-15 mg/L. In particular, the overall removal could be increased even to 97% and 99%, at 60 and 120 min, respectively, when the recirculation point was the first tank. Recirculation of PAC to either the first or the second contact tank proved to be comparable, while a slightly lower performance was observed with recirculation to

Design of a High-Reynolds Number Recirculating Water Tunnel

Science.gov (United States)

Daniel, Libin; Elbing, Brian

2014-11-01

An experimental fluid mechanics laboratory focused on turbulent boundary layers, drag reduction techniques, multiphase flows and fluid-structure interactions has recently been established at Oklahoma State University. This laboratory has three primary components; (1) a recirculating water tunnel, (2) a multiphase pipe flow loop, and (3) a multi-scale flow visualization system. The design of the water tunnel is the focus of this talk. The criteria used for the water tunnel design was that it had to produce a momentum-thickness based Reynolds number in excess of 104, negligible flow acceleration due to boundary layer growth, maximize optical access for use of the flow visualization system, and minimize inlet flow non-uniformity. This Reynolds number was targeted to bridge the gap between typical university/commercial water tunnels (103) and the world's largest water tunnel facilities (105) . These objectives were achieved with a 152 mm (6-inch) square test section that is 1 m long and has a maximum flow speed of 10 m/s. The flow non-uniformity was mitigated with the use of a tandem honeycomb configuration, a settling chamber and an 8.5:1 contraction. The design process that produced this final design will be presented along with its current status.

New developments in design and applications for Pelletron accelerators

International Nuclear Information System (INIS)

Norton, Greg

2002-01-01

Most of the developments over the last several years related to Pelletron accelerator are in the field of accelerator mass spectrometry (AMS) and other low beam current applications with the exception of a very high DC electron recirculation Pelletron. High precision AMS systems based on tandem pelletrons from 500 kV to 5 MV terminal potential are now in use for routine high precision AMS measurements. Their performance will be reported. In addition, there has been significant advancement in the design of the multi-cathode SNICS source for the use of both gas and solid samples within a single source. The latest performance of these sources will be discussed. New diagnostics is being developed for very low beam currents. The latest design of the low current beam profile monitor (LCBPM) will also be presented. (author)

An induction linac injector for scaled experiments

International Nuclear Information System (INIS)

Rutkowski, H.L.; Faltens, A.; Pike, C.; Brodzik, D.; Johnson, R.M.; Vanecek, D.; Hewett, D.W.

1991-04-01

An injector is being developed at LBL that would serve as the front end of a scaled induction linac accelerator technology experiment for heavy ion fusion. The ion mass being used is in the range 10--18. It is a multi-beam device intended to accelerate up to 2 MeV with 500 mA in each beam. The first half of the accelerating column has been built and experiments with one carbon beam are underway at the 1 MeV level. 5 refs., 1 fig

Analysis of heat recovery from a spray dryer by recirculation of exhaust air

International Nuclear Information System (INIS)

Golman, Boris; Julklang, Wittaya

2014-01-01

Highlights: • We study a spray dryer with heat recovery by partial recirculation of exhaust air. • We examine effects of process parameters on energy efficiency and energy savings. • Decreasing drying air temperature and flow rate will increase energy efficiency. • Increasing recirculation ratio and slurry feed rate will increase energy efficiency. - Abstract: Model simulations were employed to investigate the influences of process parameters on the energy recovery in spray drying process that partially recycle the exhaust drying gas. The energy efficiency and energy saving were studied for various values of recirculation ratios with respect to the temperature and flow rate of the drying air, slurry feed rate and concentration of slurry in spray drying of advanced ceramic materials. As a result, significant gains in energy efficiency and energy saving were obtained for a spray drying system with high recirculation ratio of exhaust air. The high slurry feed rate and the low slurry concentration, inlet drying air temperature and drying air flow rate enhanced the energy efficiency of spray drying system. However, the high energy saving was obtained in spray dryers operating at low slurry feed rate and high slurry concentration

Effect of self recirculation casing treatment on the performance of a turbocharger centrifugal compressor

Science.gov (United States)

Gancedo, Matthieu

Increase in emission regulations in the transport industry brings the need to have more efficient engines. A path followed by the automobile industry is to downsize the size of the internal combustion engine and increase the air density at the intake to keep the engine power when needed. Typically a centrifugal compressor is used to force the air into the engine, it can be powered from the engine shaft (superchargers) or extracting energy contained into the hot exhaust gases with a turbine (turbochargers). The flow range of the compressor needs to match the one of the engine. However compressors mass flow operating range is limited by choke on the high end and surge on the low end. In order to extend the operation at low mass flow rates, the use of passive devices for turbocharger centrifugal compressors was explored since the late 80's. Hence, casing treatments including flow recirculation from the inducer part of the compressor have been shown to move the surge limit to lower flows. Yet, the working mechanisms are still not well understood and thus, to optimize the design of this by-pass system, it is necessary to determine the nature of the changes induced by the device both on the dynamic stability of the pressure delivery and on the flow at the inlet. The compressor studied here features a self-recirculating casing treatment at the inlet. The recirculation passage could be blocked to carry a direct comparison between the cases with and without the flow feature. To grasp the effect on compressor stability, pressure measurements were taken in the different constituting elements of the compressor. The study of the mean pressure variations across the operating map showed that the tongue region is a limiting element. Dynamic pressure measurements revealed that the instabilities generated near the inducer when the recirculation is blocked increase the overall instability levels at the compressor outlet and propagating pressure waves starting at the tongue occurred

Induction linac drivers for commercial heavy-ion beam fusion

International Nuclear Information System (INIS)

Keefe, D.

1987-11-01

This paper discusses induction linac drivers necessary to accelerate heavy ions at inertial fusion targets. Topics discussed are: driver configurations, the current-amplifying induction linac, high current beam behavior and emittance growth, new considerations for driver design, the heavy ion fusion systems study, and future studies. 13 refs., 6 figs., 1 tab

Experimental investigation on the influences of exhaust gas recirculation coupling with intake tumble on gasoline engine economy and emission performance

International Nuclear Information System (INIS)

Fu, Jianqin; Zhu, Guohui; Zhou, Feng; Liu, Jingping; Xia, Yan; Wang, Shuqian

2016-01-01

Highlights: • In-cylinder residual gas fraction almost increases linearly with exhaust gas recirculation rate. • Heat transfer loss and exhaust gas energy loss decrease with exhaust gas recirculation rate. • Engine indicated thermal efficiency can be increased by 4.29% at 1600 r/min and 2.94 bar. • The effective range of exhaust gas recirculation rate can be extended by intake tumble. - Abstract: To improve the economy and emission performance of gasoline engine under part load, the approach of exhaust gas recirculation coupling with intake tumble was investigated by bench testing. Based on a naturally aspirated gasoline engine, the sweeping test of exhaust gas recirculation rate was conducted in two intake modes (with/without intake tumble), and the parameters related to engine heat-work conversion process and emission performance were measured. Through comparing and analyzing the measured data, the effects of exhaust gas recirculation coupling with intake tumble on gasoline engine economy and emission performance were revealed. The results show that pumping loss decreases gradually while in-cylinder residual gas fraction increases linearly with the exhaust gas recirculation rate increasing; the high-pressure cycle efficiency ascends with exhaust gas recirculation rate increasing due to the decrease of heat transfer loss and exhaust gas energy loss. Thus, the improvement of indicated thermal efficiency is the superposition of double benefits of low-pressure cycle and high-pressure cycle. At 1600 r/min and 2.94 bar, the indicated thermal efficiency can be increased by 4.29%. With the increase of exhaust gas recirculation rate, nitrogen oxide emissions almost fall linearly, but hydrocarbon and carbonic oxide emissions have no obvious change in the effective range of exhaust gas recirculation rate. The biggest advantage of intake tumble is that it can extend the effective range of exhaust gas recirculation rate. As a result, the potential of energy

Induction linacs as radiation processors

International Nuclear Information System (INIS)

Birx, D.L.

1986-01-01

Experiments at the Lawrence Livermore National Laboratory (LLNL), University of California, in conjunction with the University of California at Davis have shown induction linear accelerators (linacs) to be suitable for radiation processing of food. Here we describe how it might be possible to optimize this technology developded for the Department of Defense to serve in radiation processing. The possible advantages of accelerator-produced radiation over the use of radioisotopes include a tailor-made energy spectrum that can provide much deeper penetration and thereby better dose uniformity

VoxHenry: FFT-Accelerated Inductance Extraction for Voxelized Geometries

KAUST Repository

Yucel, Abdulkadir C.; Georgakis, Ioannis P.; Polimeridis, Athanasios G.; Bagci, Hakan; White, Jacob K.

2018-01-01

inductance extractor, FastHenry. Just like FastHenry, VoxHenry solves a combination of the electric volume integral equation and the current continuity equation, but with three distinctions that make VoxHenry suitable and extremely efficient for analyzing

Modeling Tar Recirculation in Biomass Fluidized Bed Gasification

NARCIS (Netherlands)

Heineken, Wolfram; De la Cuesta de Cal, Daniel; Zobel, Nico

2016-01-01

A biomass gasification model is proposed and applied to investigate the benefits of tar recirculation within a gasification plant. In the model, tar is represented by the four species phenol, toluene, naphthalene, and benzene. The model is spatially one-dimensional, assuming plug flow for the

Effect of recirculation and regional counting rate on reliability of noninvasive bicompartmental CBF measurements

International Nuclear Information System (INIS)

Herholz, K.

1985-01-01

Based on data from routine intravenous Xe133-rCBF studies in 50 patients, using Obrist's algorithm the effect of counting rate statistics and amount of recirculating activity on reproducibility of results was investigated at five simulated counting rate levels. Dependence of the standard deviation of compartmental and noncompartmental flow parameters on recirculation and counting rate was determined by multiple linear regression analysis. Those regression equations permit determination of the optimum accuracy that may be expected from individual flow measurements. Mainly due to a delay of the start-of-fit time an exponential increase in standard deviation of flow measurements was observed as recirculation increased. At constant start-of-fit, however, a linear increase in standard deviation of compartmental flow parameters only was found, while noncompartmental results remained constant. Therefore, and in regard to other studies of potential sources of error, an upper limit of 2.5 min for the start-of-fit time and usage of noncompartmental flow parameters for measurements affected by high recirculation are suggested

Heavy-Ion Fusion Accelerator Research, 1991

International Nuclear Information System (INIS)

1992-03-01

This report discusses the following topics: research with multiple- beam experiment MBE-4; induction linac systems experiments; and long- range research and development of heavy-ion fusion accelerators

Current pulse generator of an induction accelerator electromagnet

International Nuclear Information System (INIS)

Baginskij, B.A.; Makarevich, V.N.; Shtejn, M.M.

1987-01-01

Thyristor generator forming in betatron electromagnet coil sinusoidal and quasisinusoidal current unipolar pulses, the field being deforced at the beginning of acceleration cycle, and with the pulse flat top in the cycle end, is described. The current amplitude is controlled by pulse-phase method. The current pulse time shift permitted to decrease the loss rate in the accumulating capacitor. The generator is used in systems with 1-10 ms pulse duration, electromagnet magnetic field maximal energy - 45-450 J, the voltage amplitude in the coil 960-1500 V and amplitude of the current passing the coil 100-500 A, the repetition frequency being 50-200 Hz. In particular, the generator is used to supply betatrons designed for defectoscopy in nonstationary conditions, the accelerated electron energy being 4, 6, 8 and 15 MeV

[Responses of antioxidation system of Cynodon dactylon to recirculated landfill leachate irrigation].

Science.gov (United States)

Wang, Ruyi; He, Pinjing; Shao, Liming; Zhang, Bin; Li, Guojian

2005-05-01

With pot experiment, this paper studied the membrane lipid peroxidation and the variations of antioxidation system in Cynodon dactylon under recirculated landfill leachate irrigation. The results showed that when irrigated with low dilution ratio ( 25%), there existed an obvious negative fect on Cynodon dactylon, i.e., the chlorophyll a/b ratio decreased, while cell membrane permeability and MDA and H2O2 contents increased, which meant that the membrane lipid peroxidation was accelerated. The contents antioxidants AsA, GSH and Car also showed the similar trend, i.e., they increased with increasing leachate dilution ratio when irrigated with low dilution ratio leachate, but decreased under medium or high dilution ratio leachate irrigation. Among three test anti-oxidative enzymes, SOD and POD activities showed a similar change test antioxidants, and POD activity was more sensitive, while CAT activity was on the contrary. The contents test antioxidants and the activities of SOD and POD were negatively and significantly correlated to MDA content, indicating that they might play an important role in preventing Cynodon dactylon from cell membrane lipid peroxdation.

The effect of sludge recirculation rate on a UASB-digester treating domestic sewage at 15 °C.

Science.gov (United States)

Zhang, Lei; Hendrickx, Tim L G; Kampman, Christel; Zeeman, Grietje; Temmink, Hardy; Li, Weiguang; Buisman, Cees J N

2012-01-01

The anaerobic treatment of low strength domestic sewage at low temperature is an attractive and important topic at present. The upflow anaerobic sludge bed (UASB)-digester system is one of the anaerobic systems to challenge low temperature and concentrations. The effect of sludge recirculation rate on a UASB-digester system treating domestic sewage at 15 °C was studied in this research. A sludge recirculation rate of 0.9, 2.6 and 12.5% of the influent flow rate was investigated. The results showed that the total chemical oxygen demand (COD) removal efficiency rose with increasing sludge recirculation rate. A sludge recirculation rate of 0.9% of the influent flow rate led to organic solids accumulation in the UASB reactor. After the sludge recirculation rate increased from 0.9 to 2.6%, the stability of the UASB sludge was substantially improved from 0.37 to 0.15 g CH₄-COD/g COD, and the bio-gas production in the digester went up from 2.9 to 7.4 L/d. The stability of the UASB sludge and bio-gas production in the digester were not significantly further improved by increasing sludge recirculation rate to 12.5% of the influent flow rate, but the biogas production in the UASB increased from 0.37 to 1.2 L/d. It is recommended to apply a maximum sludge recirculation rate of 2-2.5% of the influent flow rate in a UASB-digester system, as this still allows energy self-sufficiency of the system.

Validation of enhanced stabilization of municipal solid waste under controlled leachate recirculation using FTIR and XRD.

Science.gov (United States)

Sethi, Sapna; Kothiyal, N C; Nema, Arvind K

2012-07-01

Leachate recirculation at neutral PH accompanied with buffer/nutrients addition has been used successfully in earlier stabilization of municipal solid waste in bioreactor landfills. In the present study, efforts were made to enhance the stabilization rate of municipal solid waste (MSW) and organic solid waste (OSW) in simulated landfill bioreactors by controlling the pH of recirculated leachate towards slightly alkaline side in absence of additional buffer and nutrients addition. Enhanced stabilization in waste samples was monitored with the help of analytical tools like Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD). Predominance of bands assigned to inorganic compounds and comparatively lower intensities of bands for organic compounds in the FTIR spectra of waste samples degraded with leachate recirculation under controlled pH confirmed higher rate of biodegradation and mineralization of waste than the samples degraded without controlled leachate recirculation. XRD spectra also confirmed to a greater extent of mineralization in the waste samples degraded under leachate recirculation with controlled pH. Comparison of XRD spectra of two types of wastes pointed out higher degree of mineralization in organic solid waste as compared to municipal solid waste.

Study on performance and emission characteristics of a single cylinder diesel engine using exhaust gas recirculation

Directory of Open Access Journals (Sweden)

Anantha Raman Lakshmipathi

2017-01-01

Full Text Available Exhaust gas re-circulation is a method used in compression ignition engines to control and reduce NOx emission. These emissions are controlled by reducing the oxygen concentration inside the cylinder and thereby reducing the flame temperature of the charge mixture inside the combustion chamber. In the present investigation, experiments were performed to study the effect of exhaust gas re-circulation on performance and emission characteristics in a four stroke single cylinder, water cooled and constant speed diesel engine. The experiments were performed to study the performance and emissions for different exhaust gas re-circulation ratios of the engine. Performance parameters such as brake thermal efficiency, indicated thermal efficiency, specific fuel consumption, total fuel consumption and emission parameters such as oxides of nitrogen, unburned hydrocarbons, carbon monoxide, carbon dioxide and smoke opacity were measured. Reductions in NOx and CO2 were observed but other emissions like HC, CO, and smoke opacity were found to have increased with the usage of exhaust gas re-circulation. The 15% exhaust gas re-circulation was found optimum for the engine in the aspects of performance and emission.

Cost/performance analysis of an induction linac driver system for inertial fusion

International Nuclear Information System (INIS)

Hovingh, J.; Brady, V.O.; Faltens, A.; Hoyer, E.H.; Lee, E.P.

1986-01-01

A linear induction accelerator that produces a beam of energetic (≅ 10 GeV) heavy (A ≅ 200) ions is a prime candidate as a driver for inertial fusion. Continuing developments is amorphous iron for use in accelerating modules represent a potentially large reduction in the driver cost and an increase in the driver efficiency. Additional insulator developments may also represent a potentially large reduction in the driver cost. The efficiency and cost of the induction linac system is discussed as a function of output energy and pulse repetition frequency for several beam charge states, numbers of beams and beam particle species. Accelerating modules and transport modules are described. Large cost leverage items are identified as a guide to future research activities and technology of development that can yield further substantial reductions in the accelerator system cost and improvement in the accelerator system efficiency

Cost/performance analysis of an induction linac driver system for inertial fusion

International Nuclear Information System (INIS)

Hovingh, J.; Brady, V.O.; Faltens, A.; Hoyer, E.H.; Lee, E.P.

1985-11-01

A linear induction accelerator that produces a beam of energetic (approx. =10 GeV) heavy (CAapprox.200) ions is a prime candidate as a driver for inertial fusion. Continuing developments in amorphous iron for use in accelerating modules represent a potentially large reduction in the driver cost and an increase in the driver efficiency. Additional insulator developments may also represent a potentially large reduction in the driver cost. The efficiency and cost of the induction linac system is discussed as a function of output energy and pulse repetition frequency for several beam charge states, numbers of beams and beam particle species. Accelerating modules and transport modules will be described. Large cost leverage items will be identified as a guide to future research activities and technology of development that can yield further substantial reductions in the accelerator system cost and improvement in the accelerator system efficiency. 13 refs., 2 figs

Experiments and prospects for induction linac drivers

International Nuclear Information System (INIS)

Keefe, D.

1986-05-01

In the last three years, the US program in Heavy Ion Fusion has concentrated on understanding the induction linac approach to a power-plant driver. In this method it is important that the beam current be maximized throughout the accelerator. Consequently, it is crucial to understand the space-charge limit in the AG transport system in the linac and, also, to achieve current amplification during acceleration to keep pace with the kinematical increase of this limit with energy. Experimental results on both these matters and also on the use of multiple beams (inside the same accelerating structure) will be described. A new examination of the most attractive properties of the induction linac for a fusion driver has clearly pointed to the advantage of using heavy ions with a charge-state greater than unity - perhaps q = 3 may be an optimum. This development places even greater importance on understanding space-charge limits and mechanisms for emittance growth; also, it will require a new emphasis on the development of a suitable ion source

Experiments and prospects for induction linac drivers

International Nuclear Information System (INIS)

Keefe, D.

1986-12-01

In the last three years, the US program in Heavy Ion Fusion has concentrated on understanding the induction linac approach to a power-plant driver. In this method it is important that the beam current be maximized throughout the accelerator. Consequently, it is crucial to understand the space-charge limit in the AG transport system in the linac and, also, to achieve current amplification during acceleration to keep pace with the kinematical increase of this limit with energy. Experimental results on both these matters and also on the use of multiple beams (inside the same accelerating structure) will be described. A new examination of the most attractive properties of the induction linac for a fusion driver has clearly pointed to the advantage of using heavy ions with a charge-state greater than unity - perhaps q = 3 may be an optimum. This development places even greater importance on understanding space-charge limits and mechanisms for emittance growth; also, it will require a new emphasis on the development of a suitable ion source

Combined production of fish and plants in recirculating water

Energy Technology Data Exchange (ETDEWEB)

Naegel, L.C.A.

1977-01-01

A pilot plant of ca 2000 l of recirculating fresh water for intensive fish production was constructed in a controlled-environment greenhouse. The feasibility was examined of using nutrients from fish wastewater, mainly oxidized nitrogenous compounds, for plant production, combined with an activated sludge system for water purification. The reduction of nitrates, formed during the extended aeration process by nitrifying bacteria, was not sufficient by higher plants and unicellular algae alone to reduce the nitrate concentration in our system significantly. An additional microbial denitrification step had to be included to effect maximal decrease in nitrogenous compounds. For fish culture in the pilot plant Tilapia mossambica and Cyprinus carpio were chosen as experimental fishes. Both fish species showed significant weight increases during the course of the experiment. Ice-lettuce and tomatoes were tested both in recirculating water and in batch culture. The unicellular algae Scenedesmus spp. were grown in a non-sterile batch culture. All plants grew well in the wastewater without additional nutrients. Determination of the physical and chemical parameters for optimum water purification, the most suitable ratio of denitrification by plants and by microorganisms, and the most favourable fish and plant species for combined culture in recirculating water are important and of current interest in view of the increasing demand for clean, fresh water, and the pressing need to find new ways of producing protein for human nutrition under prevailing conditions of an exponentially expanding world population.

Updating the induction module from single-pulse to double-pulses

International Nuclear Information System (INIS)

Huang Ziping; Wang Huacen; Deng Jianjun

2002-01-01

A double-pulse Linear Induced Accelerator (LIA) module is reconstructed based on a usual simple-pulse LIA module. By changing the length of one of the cables between the inductive cell and the Blumlein pulse forming line, two induction pulses with 90 ns FWHM and 150 kV pulse voltage are generated by the ferrite cores inductive cell. The interval time of the pulses is adjustable by changing the lengths of the cable

Recirculator "SALO" - A basis for creation of a model of sub-critical reactor controlled by the accelerator

NARCIS (Netherlands)

Gann, V.V.; Guk, I.S.; Dovbnya, A.N.; Kononenko, S.G.; Kostromin, A.S.; Peev, F.A.; Prochorets, I.M.; Soldatov, C.A.; Tarasenko, A.S.; Wiel, van der M.J.; Botman, J.I.M.

2006-01-01

Recently opportunities of creation test facility with sub-crit. reactors controlled by accelerators of particles are actively discussed. At an initial stage of these researches it is the most expedient to use electron accelerators as cost of such facility will be much less, than at use of proton

Impacts of aeration and active sludge addition on leachate recirculation bioreactor

International Nuclear Information System (INIS)

Dong Jun; Zhao Yongsheng; Henry, Rotich K.; Hong Mei

2007-01-01

Stabilization of municipal solid waste (MSW) is affected by moisture, nutrients, oxygen, pH and accumulation of inhibitory fermentation products, etc. Optimization of these parameters could create a favorable environment that promotes the rapid development of the desired microbial population and acceleration of decomposition of MSW. The objectives of this work was to determine the feasibility of enhancing phase separation through intermittent aeration strategy throughout the treatment process; to demonstrate the potential of active sludge for in situ nitrogen removal; to examine the efficiency and evaluate the possibility of in situ removal of contaminants from leachate. The results indicate that the removal ratio of COD, BOD 5 , NH 4 + and total nitrogen are over 80, 81, 75, and 74%, respectively, in the leachate recirculation reactors with aeration; the removal efficiency of NH 4 + and total nitrogen of the reactor which were added active sludge were 88 and 84%, respectively. Therefore, aeration strategy has positive impacts on the solid waste stabilization; addition of active sludge in reactor is favorable for the remediation of the nitrogen; using landfill itself for in situ attenuating the contaminants from leachate is feasible

Coupling and decoupling of the accelerating units for pulsed synchronous linear accelerator

Science.gov (United States)

Shen, Yi; Liu, Yi; Ye, Mao; Zhang, Huang; Wang, Wei; Xia, Liansheng; Wang, Zhiwen; Yang, Chao; Shi, Jinshui; Zhang, Linwen; Deng, Jianjun

2017-12-01

A pulsed synchronous linear accelerator (PSLA), based on the solid-state pulse forming line, photoconductive semiconductor switch, and high gradient insulator technologies, is a novel linear accelerator. During the prototype PSLA commissioning, the energy gain of proton beams was found to be much lower than expected. In this paper, the degradation of the energy gain is explained by the circuit and cavity coupling effect of the accelerating units. The coupling effects of accelerating units are studied, and the circuit topologies of these two kinds of coupling effects are presented. Two methods utilizing inductance and membrane isolations, respectively, are proposed to reduce the circuit coupling effects. The effectiveness of the membrane isolation method is also supported by simulations. The decoupling efficiency of the metal drift tube is also researched. We carried out the experiments on circuit decoupling of the multiple accelerating cavity. The result shows that both circuit decoupling methods could increase the normalized voltage.

The Effect of Effluent Recirculation in a Semi-Continuous Two-Stage Anaerobic Digestion System

Directory of Open Access Journals (Sweden)

Karthik Rajendran

2013-06-01

Full Text Available The effect of recirculation in increasing organic loading rate (OLR and decreasing hydraulic retention time (HRT in a semi-continuous two-stage anaerobic digestion system using stirred tank reactor (CSTR and an upflow anaerobic sludge bed (UASB was evaluated. Two-parallel processes were in operation for 100 days, one with recirculation (closed system and the other without recirculation (open system. For this purpose, two structurally different carbohydrate-based substrates were used; starch and cotton. The digestion of starch and cotton in the closed system resulted in production of 91% and 80% of the theoretical methane yield during the first 60 days. In contrast, in the open system the methane yield was decreased to 82% and 56% of the theoretical value, for starch and cotton, respectively. The OLR could successfully be increased to 4 gVS/L/day for cotton and 10 gVS/L/day for starch. It is concluded that the recirculation supports the microorganisms for effective hydrolysis of polyhydrocarbons in CSTR and to preserve the nutrients in the system at higher OLRs, thereby improving the overall performance and stability of the process.

Hyperthermia induced after recirculation triggers chronic neurodegeneration in the penumbra zone of focal ischemia in the rat brain

Directory of Open Access Journals (Sweden)

L.A. Favero-Filho

2008-11-01

Full Text Available Chronic neurodegenerative processes have been identified in the rat forebrain after prolonged survival following hyperthermia (HT initiated a few hours after transient global ischemia. Since transient global ischemia and ischemic penumbra share pathophysiological similarities, this study addressed the effects of HT induced after recirculation of focal brain ischemia on infarct size during long survival times. Adult male Wistar rats underwent intra-luminal occlusion of the left middle cerebral artery for 60 min followed by HT (39.0-39.5°C or normothermia. Control procedures included none and sham surgery with and without HT, and middle cerebral artery occlusion alone. Part I: 6-h HT induced at recirculation. Part II: 2-h HT induced at 2-, 6-, or 24-h recirculation. Part III: 2-h HT initiated at recirculation or 6-h HT initiated at 2-, 6- or 24-h recirculation. Survival periods were 7 days, 2 or 6 months. The effects of post-ischemic HT on cortex and striatum were evaluated histopathologically by measuring the area of remaining tissue in the infarcted hemisphere at -0.30 mm from bregma. Six-hour HT initiated from 6-h recirculation caused a significant decrease in the remaining cortical tissue between 7-day (N = 8 and 2-month (N = 8 survivals (98.46 ± 1.14 to 73.62 ± 8.99%, respectively. When induced from 24-h recirculation, 6-h HT caused a significant reduction of the remaining cortical tissue between 2- (N = 8 and 6-month (N = 9 survivals (94.97 ± 5.02 vs 63.26 ± 11.97%, respectively. These data indicate that post-ischemic HT triggers chronic neurodegenerative processes in ischemic penumbra, suggesting that similar fever-triggered effects may annul the benefit of early recirculation in stroke patients over the long-term.

New type of magnetohydrodynamic converters: induction devices

International Nuclear Information System (INIS)

Petit, J.-P.; Viton, Maurice.

1977-01-01

A new induction MHD accelerator, disc shaped, with controlled ionization, is presented. Associated with a light and powerful electric generator it could become a MHD aerodyne. Solutions for confining the plasma to the wall are indicated [fr

An induction Linac approach to phase rotation of a muon bunch in the production region of μ+-μ- colliders

International Nuclear Information System (INIS)

Turner, W.C.

1995-01-01

The possibility of using an induction linac for phase rotation, or equivalently flattening the head to tail mean energy sweep, of a muon bunch in the production region of a μ + - μ - is examined. Axial spreading of an accelerating bunch is analyzed and the form of appropriate induction cell voltage waveforms is derived. A set of parametric equations for the induction accelerator structure is given and specific solutions are presented which demonstrate the technological feasibility of the induction linac approach to phase rotation

A replacement LH2 recirculation line before installation in Discovery

Science.gov (United States)

1999-01-01

A spare four-inch diameter LH2 recirculation line (shown in photo) will be used to replace a damaged LH2 line in the orbiter Discovery. The line recirculates hydrogen from the Shuttle main engines back to the external tank during prelaunch engine conditioning. Workers noted a dent in the line during routine aft compartment inspections Tuesday, Dec. 7. The dent measures 12 inches long and about =-inch deep. Managers expect the replacement work to take about 3 days, followed by system retests and final aft compartment close-outs. Preliminary assessments reflect a launch date of Space Shuttle Discovery on mission STS-103 no earlier than Dec. 16. STS-103 is the third servicing mission for the Hubble Space Telescope.

Performance of Water Recirculation Loop Maintentance Components for the Advanced Spacesuit Water Membrane Evaporator

Science.gov (United States)

Rector, Tony; Peyton, Barbara; Steele, John W.; Bue, Grant C.; Campbell, Colin; Makinen, Janice

2014-01-01

Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a second SWME water recirculation loop with no water quality maintenance. Results show the benefits of periodic water maintenance. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the evaluation of water recirculation maintenance components was to further enhance this advantage through the leveraging of fluid loop management lessonslearned from the International Space Station (ISS). A bed design that was developed for a UTAS military application, and considered for a potential ISS application with the Urine Processor Assembly, provided a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for ISS to introduce a biocide in a microgravity-compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

Performance of Water Recirculation Loop Maintenance Components for the Advanced Spacesuit Water Membrane Evaporator

Science.gov (United States)

Rector, Tony; Peyton, Barbara M.; Steele, John W.; Makinen, Janice; Bue, Grant C.; Campbell, Colin

2014-01-01

Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a second SWME water recirculation loop with no water quality maintenance. Results show the benefits of periodic water maintenance. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the evaluation of water recirculation maintenance components was to further enhance this advantage through the leveraging of fluid loop management lessons learned from the International Space Station (ISS). A bed design that was developed for a UTAS military application, and considered for a potential ISS application with the Urine Processor Assembly, provided a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for ISS to introduce a biocide in a microgravity compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

Freshwater Institute: Focused on improving recirculating aquaculture system technology

Science.gov (United States)

Recirculating aquaculture system (RAS) technologies help to overcome barriers to domestic aquaculture expansion and enhance the sustainability of the modern fish farming industry through reduction in environmental impacts. With RAS, fish farm expansion is no longer highly constrained by competition ...

STUDIES REGARDING THE PRESENCE OF THE PATHOGENS BACTERIA INTO A RECIRCULATING SYSTEM OF BELUGA STURGEON INTENSIVE REARING

Directory of Open Access Journals (Sweden)

ANGELICA DOCAN

2008-10-01

Full Text Available Recirculating aquaculture offers good potential for successful fish farming since is often independent of environmental conditions. Maintaining healthy fish in a recirculating system involves establishing adequate dissolved oxygen levels, removal of solid wastes, and sufficient ammonia nitrification to assure optimal rearing conditions. Neglecting these, the fish immune system will depress, the facultative pathogen germs will be able to provoke important disease outbreaks into cultured biomass, as was happened in our recirculating pilot system. In this study are presented the pathological aspects registered to the beluga sturgeon of 1 year, reared into our recirculating pilot system, pathological aspects generated by a haemorrhagic bacterial septicaemia which was manifested in the conditions of low concentrations of DO. The disease was diagnosed to the affected fish through anatomopathological and clinical exam, haematological exam and microbiological exam.

Multi-beam linear accelerator EVT

Energy Technology Data Exchange (ETDEWEB)

Teryaev, Vladimir E., E-mail: vladimir_teryaev@mail.ru [Omega-P, Inc., New Haven, CT 06510 (United States); Kazakov, Sergey Yu. [Fermilab, Batavia, IL 60510 (United States); Hirshfield, Jay L. [Omega-P, Inc., New Haven, CT 06510 (United States); Yale University, New Haven, CT 06511 (United States)

2016-09-01

A novel electron multi-beam accelerator is presented. The accelerator, short-named EVT (Electron Voltage Transformer) belongs to the class of two-beam accelerators. It combines an RF generator and essentially an accelerator within the same vacuum envelope. Drive beam-lets and an accelerated beam are modulated in RF modulators and then bunches pass into an accelerating structure, comprising uncoupled with each other and inductive tuned cavities, where the energy transfer from the drive beams to the accelerated beam occurs. A phasing of bunches is solved by choice correspond distances between gaps of the adjacent cavities. Preliminary results of numerical simulations and the initial specification of EVT operating in S-band, with a 60 kV gun and generating a 2.7 A, 1.1 MV beam at its output is presented. A relatively high efficiency of 67% and high design average power suggest that EVT can find its use in industrial applications.

Asymptotic analysis of the longitudinal instability of a heavy ion induction linac

International Nuclear Information System (INIS)

Lee, E.P.; Smith, L.

1990-09-01

An Induction Linac accelerating high ion currents at sub-relativistic energies is predicted to exhibit unstable growth of current fluctuations at low frequencies. The instability is driven by the interaction between the beam and complex impedance of the induction modules. In general, the detailed form of the growing disturbance depends on the initial perturbation and ratio of pulse length to accelerator length, as well as the specific form of the impedance. An asymptotic analysis of the several regimes of interest is presented. 1 ref

Boiler recirculation pumps for nuclear power stations - present state of development. Directions for planning, operational experience

International Nuclear Information System (INIS)

Mattias, H.B.

1976-01-01

Boiler recirculation pumps are important components of modern power stations. The development of large recirculation pumps up to a driving power of 1,500 kW was faced with some problems in meeting the plant requirements. In this paper, the present state of development is dealt with. The development problems in the fields of hydrodynamics, cavitation, corrosion and erosion are dealt with as well as the problems of the design of the casing with regard to thermodynamics and strength. Finally, operational experience with the boiler recirculation pump for 600 MW power stations will be reported on. (orig./AK) [de

Preliminary results from MBE-4: A four beam induction linac for heavy ion fusion research

International Nuclear Information System (INIS)

Fessenden, T.J.; Judd, D.L.; Keefe, D.; Kim, C.; Laslett, L.J.; Smith, L.; Warwick, A.I.; Warwick, P.b.A.I.

1986-01-01

Preliminary results are presented from a scaled experimental multiple beam induction linac. This experiment is part of a program of accelerator research for heavy ion fusion. It is shown that multiple beams can be accelerated without significant mutual interaction. Measurements of the longitudinal dynamics of a current-amplifying induction linac are presented and compared to calculations. Coupling of transverse and longitudinal dynamics is discussed

Preliminary results from MBE-4: a four beam induction linac for heavy ion fusion research

International Nuclear Information System (INIS)

Fessenden, T.J.; Judd, D.L.; Keefe, D.; Kim, C.; Laslett, L.J.; Smith, L.; Warwick, A.I.

1986-05-01

Preliminary results are presented from a scaled experimental multiple beam induction linac. This experiment is part of a program of accelerator research for heavy ion fusion. It is shown that multiple beams can be accelerated without significant mutual interaction. Measurements of the longitudinal dynamics of a current-amplifying induction linac are presented and compared to calculations. Coupling of transverse and longitudinal dynamics is discussed

Control oriented modeling of ejector in anode gas recirculation solid oxygen fuel cell systems

International Nuclear Information System (INIS)

Zhu Yinhai; Li Yanzhong; Cai Wenjian

2011-01-01

A one-equation model is proposed for fuel ejector in anode gas recirculation solid oxide fuel cell (SOFC) system. Firstly, the fundamental governing equations are established by employing the thermodynamic, fluid dynamic principles and chemical constraints inside the ejector; secondly, the one-equation model is derived by using the parameter analysis and lumped-parameter method. Finally, the computational fluid dynamics (CFD) technique is employed to obtain the source data for determining the model parameters. The effectiveness of the model is studied under a wide range of operation conditions. The effect of ejector performance on the anode gas recirculation SOFC system is also discussed. The presented model, which only contains four constant parameters, is useful in real-time control and optimization of fuel ejector in the anode gas recirculation SOFC system.

Prophage λ induction by ionizing radiation of different LETs

International Nuclear Information System (INIS)

Bonev, M.N.; Kozubek, S.; Krasavin, E.A.; Amirtaev, K.G.

1988-01-01

The λ prophage induction caused by γ-irradiation and accelerated heavy ions with different LET was studied in variety Escherichia coli strains. The induction frequency on the dose I(D) shaped a curve with a maximum in the strains which possess recA + /lexA + genotype. The inductivity of these strains increases as well as LET and an alteration poor → rich media does it. Unlike I(D) for recA + /lexA + , the dependence I(D) for recA, lexA and recBC strains was a constant. 15 refs.; 6 figs.; 3 tabs

Cost optimization of induction linac drivers for linear colliders

International Nuclear Information System (INIS)

Barletta, W.A.

1986-01-01

Recent developments in high reliability components for linear induction accelerators (LIA) make possible the use of these devices as economical power drives for very high gradient linear colliders. A particularly attractive realization of this ''two-beam accelerator'' approach is to configure the LIA as a monolithic relativistic klystron operating at 10 to 12 GHz with induction cells providing periodic reacceleration of the high current beam. Based upon a recent engineering design of a state-of-the-art, 10- to 20-MeV LIA at Lawrence Livermore National Laboratory, this paper presents an algorithm for scaling the cost of the relativistic klystron to the parameter regime of interest for the next generation high energy physics machines. The algorithm allows optimization of the collider luminosity with respect to cost by varying the characteristics (pulse length, drive current, repetition rate, etc.) of the klystron. It also allows us to explore cost sensitivities as a guide to research strategies for developing advanced accelerator technologies

Heavy ion induction linac drivers for inertial confinement fusion

International Nuclear Information System (INIS)

Lee, E.P.; Hovingh, J.

1988-10-01

Intense beams of high energy heavy ions (e.g., 10 GeV Hg) are an attractive option for an ICF driver because of their favorable energy deposition characteristics. The accelerator systems to produce the beams at the required power level are a development from existing technologies of the induction linac, rf linac/storage ring, and synchrotron. The high repetition rate of the accelerator systems, and the high efficiency which can be realized at high current make this approach especially suitable for commercial ICF. The present report gives a summary of the main features of the induction linac driver system, which is the approach now pursued in the USA. The main subsystems, consisting of injector, multiple beam accelerator at low and high energy, transport and pulse compression lines, and final focus are described. Scale relations are given for the current limits and other features of these subsystems. 17 refs., 1 fig., 1 tab

Economic Feasibility of Recirculating Aquaculture Systems in Pangasius Farming

NARCIS (Netherlands)

Pham, T.A.N.; Gielen-Meuwissen, M.P.M.; Le, T.C.; Verreth, J.A.J.; Bosma, R.H.; Oude Lansink, A.G.J.M.

2016-01-01

This study aims to analyze the economic feasibility of recirculating aquaculture systems (RAS) in pangasius farming in Vietnam. The study uses a capital budgeting approach and accounts for uncertainty in key parameters. Stochastic simulation is used to simulate the economic performance of medium and

Digital feedwater and recirculation flow control for GPUN Oyster Creek

International Nuclear Information System (INIS)

Burjorjee, D.; Gan, B.

1992-01-01

This paper describes the digital system for feedwater and recirculation control that GPU Nuclear will be installing at Oyster Creek during its next outage - expected circa December 1992. The replacement was motivated by considerations of reliability and obsolescence - the analog equipment was aging and reaching the end of its useful life. The new system uses Atomic Energy of Canada Ltd.'s software platform running on dual, redundant, industrial-grade 386 computers with opto-isolated field input/output (I/O) accessed through a parallel bus. The feedwater controller controls three main feed regulating valves, two low flow regulating valves, and two block valves. The recirculation controller drives the five scoop positioners of the hydraulic couplers. The system also drives contacts that lock up the actuators on detecting an open circuit in their current loops

A dented LH2 recirculation line is removed from Discovery

Science.gov (United States)

1999-01-01

In the Payload Changeout Room, Launch Pad 39B, United Space Alliance and NASA workers look at the replacement main propulsion system liquid hydrogen recirculation line (left) to be installed in Shuttle Discovery's aft compartment. At right is the dented line that has been removed. The 12-inch-long dent was discovered during routine aft compartment inspections Tuesday, Dec. 7. The line recirculates hydrogen from the Shuttle main engines back to the external tank during prelaunch engine conditioning. The line is being replaced and managers expect the replacement work to take about 3 days, followed by system retests and final aft compartment close-outs. Preliminary assessments reflect a launch date of Space Shuttle Discovery on mission STS-103 no earlier than Dec. 16. STS-103 is the third servicing mission for the Hubble Space Telescope.

Emission characteristics of iso-propanol/gasoline blends in a spark-ignition engine combined with exhaust gas re-circulation

Directory of Open Access Journals (Sweden)

Gong Jing

2014-01-01

Full Text Available Experiments were carried out in a spark-ignition engine fueled with iso-propanol/gasoline blends. Emission characteristics of this engine were investigated experimentally, including gaseous emissions (HC, CO, NOx and particulate matter emission in term of number and size distributions. The effects of different iso-propanol percentages, loads and exhaust gas recirculation rates on emissions were analyzed. Results show that the introduction of exhaust gas recirculation reduces the NOx emission and NOx emission gives the highest value at full load condition. HC and CO emissions present inconspicuous variations at all the loads except the load of 10%. Additionally, HC emission shows a sharp increase for pure propanol when the exhaust gas recirculation rate is up to 5%, while little variation is observed at lager exhaust gas recirculation rates. Moreover, the particulate matter number concentration increases monotonically with the increase of load and the decrease of exhaust gas recirculation rate. There exists a critical spark timing that produces the highest particulate matter number concentration at all the blending ratios.

Very high pulse-energy accelerators

International Nuclear Information System (INIS)

Ramirez, J.J.

1989-01-01

The dominant trend in the development of pulsed power accelerator technology over the last decade has been towards higher power and shorter pulse widths. Limitations in high voltage, high current switch performance, and in power flow through vacuum insulator housings led to the development of highly modular designs. This modular approach requires precise synchronization of the various modules and efficient methods of combining the power from these modules to drive a common load. The need to drive very low impedance loads led to effective ways to combine these modules in parallel. The Particle Beam Fusion Accelerator I (PBFA I) and Saturn are representative of these designs. Hermes III represent a new approach towards the efficient generation of higher voltages. It is designed to drive a 22-MV, 730-kA, 40-ns electron beam diode and combines conventional, modular pulsed power technology with linear induction accelerator concepts. High-power induction accelerator cavities are combined with voltage addition along a MITL to generate the desired output. This design differs from a conventional linac in that the voltages are added by the MITL flow rather than by a drifting beam that gains kinetic energy at each stage. This design is a major extrapolation of previous state-of-the-art technology represented by the injector module of the Advanced Test Accelerator and has proven to be efficient and reliable. The design and performance of Hermes III are presented together with a discussion of the application of this technology to the light ion beam inertial confinement fusion program. 18 refs., 9 figs

Investigation of a combined gas-steam system with flue gas recirculation

Directory of Open Access Journals (Sweden)

Chmielniak Tadeusz

2016-06-01

Full Text Available This article presents changes in the operating parameters of a combined gas-steam cycle with a CO2 capture installation and flue gas recirculation. Parametric equations are solved in a purpose-built mathematical model of the system using the Ebsilon Professional code. Recirculated flue gases from the heat recovery boiler outlet, after being cooled and dried, are fed together with primary air into the mixer and then into the gas turbine compressor. This leads to an increase in carbon dioxide concentration in the flue gases fed into the CO2 capture installation from 7.12 to 15.7%. As a consequence, there is a reduction in the demand for heat in the form of steam extracted from the turbine for the amine solution regeneration in the CO2 capture reactor. In addition, the flue gas recirculation involves a rise in the flue gas temperature (by 18 K at the heat recovery boiler inlet and makes it possible to produce more steam. These changes contribute to an increase in net electricity generation efficiency by 1%. The proposed model and the obtained results of numerical simulations are useful in the analysis of combined gas-steam cycles integrated with carbon dioxide separation from flue gases.

A phase II study of hyperfractionated accelerated radiotherapy (HART) after induction cisplatin (CDDP) and vinorelbine (VNR) for stage III Non-small-cell lung cancer (NSCLC)

International Nuclear Information System (INIS)

Ishikura, Satoshi; Ohe, Yuichiro; Nihei, Keiji; Kubota, Kaoru; Kakinuma, Ryutaro; Ohmatsu, Hironobu; Goto, Koichi; Niho, Seiji; Nishiwaki, Yutaka; Ogino, Takashi

2005-01-01

Purpose: The purpose was to assess the feasibility and efficacy of hyperfractionated accelerated radiotherapy (HART) after induction chemotherapy for Stage III non-small-cell lung cancer. Methods and materials: Treatment consisted of 2 cycles of cisplatin 80 mg/m 2 on Day 1 and vinorelbine 25 mg/m 2 on Days 1 and 8 every 3 weeks followed by HART, 3 times a day (1.5, 1.8, 1.5 Gy, 4-h interval) for a total dose of 57.6 Gy. Results: Thirty patients were eligible. Their median age was 64 years (range, 46-73 years), 24 were male, 6 were female, 8 had performance status (PS) 0, 22 had PS 1, 9 had Stage IIIA, and 21 had Stage IIIB. All but 1 patient completed the treatment. Common grade ≥3 toxicities during the treatment included neutropenia, 25; infection, 5; esophagitis, 5; and radiation pneumonitis, 3. The overall response rate was 83%. The median survival was 24 months (95% confidence interval [CI], 13-34 months), and the 2-year overall survival was 50% (95% CI, 32-68%). The median progression-free survival was 10 months (95% CI, 8-20 months). Conclusion: Hyperfractionated accelerated radiotherapy after induction of cisplatin and vinorelbine was feasible and promising. Future investigation employing dose-intensified radiotherapy in combination with chemotherapy is needed

Recirculating electric air filter for use in confined spaces

International Nuclear Information System (INIS)

Bergman, W.; Biermann, A.; Kuhl, W.

1985-01-01

We have developed recirculating electric air filters for use in confined spaces where the existing ventilation system is not adequate for removing suspended particles. Two experimental filters were built and evaluated, both of which consisted of a cylindrical cartridge filter fitted over an air blower. In one design the cylindrical cartridge is a disposable unit with the electrodes and filter medium built as an integrated unit. The second design has a cylindrical cartridge that can be easily disassembled to allow replacement of the filter medium. Both designs were evaluated in a 354-ft 3 test cell using NaCl aerosols. The second design was installed and evaluated in a chamber where highly radioactive 238 PuO 2 powder is formed into pellets. We have derived equations that describe the theory of recirculating air filters. The predicted performance compares well with experimental measurements under controlled conditions. 2 refs., 7 figs., 1 tab. (DT)

Beam dynamics in stripline linear induction accelerators

International Nuclear Information System (INIS)

Adler, R.J.

1983-01-01

Stripline (parallel plate transmission line) pulsed power modules have been considered for application to advanced high current linear accelerators. Some advantages of the stripline designs include compact size, easy maintenance, and most importantly, the small number of switches required (one switch per 2 MeV). The principle drawback of stripline designs is that they impart a NET transverse force to particles in the gap. This is shown to result in randomized transverse momentum, and NET, constructive transverse guiding center motion. In this paper, a semi-quantitative analysis of several facets of the problem is presented

Power Transfer to plasma Coxial accelerator

International Nuclear Information System (INIS)

El-Aragi, G.M.; Soliman, H.M.; Masoud, M.M.

2000-01-01

The total power transfer from the condenser bank, to plasma coaxial accelerator device is theoretically studied by using the voltage equation of the entire circuit and applying impulse - linear momentum theorem. This total power represents a combination of (a) the power flowing to the external inductance, (b) the power flowing to the inductance of that part of electrode system between the breech and the momentary position of the plasma current sheath, (c) the power flowing in the annular space between the two coaxial electrodes, to form the magnetic field induction, (d) the power flowing to accelerate the initial mass, (e) the power flowing to accelerate the mass, which has been swept up into the plasma current sheath, (f) the power, which produces directed kinetic energy for the plasma current sheath, (g) the power, which produces internal energy in the plasma sheath, (h) the joule heating. The peak value of the total power = 6x10 8 watt at t=4 MUs, for maximum calculated discharge current = 110KA with a with a period of 34 us. Experimentally its equal to 3.5x10 8 watt at 7MUs and I 0 = 85KA. The energy flow to the coaxial discharge system has been evaluated theoretically and experimentally, E-MAX (CALCULATED)=5.92X10 2 J AT T = 5.5 MUs and E m ax (measured) = 3.54x10 2 joule at 7.5 MUs

High-gradient electron accelerator powered by a relativisitic klystron

International Nuclear Information System (INIS)

Allen, M.A.; Boyd, J.K.; Callin, R.S.; Deruyter, H.; Eppley, K.R.; Fant, K.S.; Fowkes, W.R.; Haimson, J.; Hoag, H.A.; Hopkins, D.B.; Houck, T.; Koontz, R.F.; Lavine, T.L.; Loew, G.A.; Mecklenburg, B.; Miller, R.H.; Ruth, R.D.; Ryne, R.D.; Sessler, A.M.; Vlieks, A.E.; Wang, J.W.; Westenskow, G.A.; Yu, S.S.

1989-01-01

We have used relativistic klystron technology to extract 290 MW of peak power at 11.4 GHz from an induction linac beam, and to power a short 11.4-GHz high-gradient accelerator. We have measured rf phase stability, field emission, and the momentum spectrum of an accelerated electron beam. An average accelerating gradient of 84 MV/m has been achieved with 80 MW of relativistic klystron power

Implementation of multiple measures to improve reactor recirculation pump sealing performance in nuclear boiling water reactor service

Energy Technology Data Exchange (ETDEWEB)

Loenhout, Gerard van [Flowserve B.V., Etten-Leur (Netherlands). Nuclear Services and Solutions Engineering; Hurni, Juerg

2014-07-01

A modern reactor recirculation pump circulates a large volume of high temperature, very pure water from the reactor pressure vessel back to the core. A crucial technical problem with a recirculation pump, such as a mechanical seal indicating loss of sealing pressure, may result in a power station having to shut down for repair. The paper describes the sudden increase in stray current phenomenon leading to rapid and severe deterioration of the mechanical end face shaft seal in a reactor recirculation pump. This occurred after the installation of a variable frequency converter replacing the original motorgenerator set.

Implementation of multiple measures to improve reactor recirculation pump sealing performance in nuclear boiling water reactor service

International Nuclear Information System (INIS)

Loenhout, Gerard van; Hurni, Juerg

2014-01-01

A modern reactor recirculation pump circulates a large volume of high temperature, very pure water from the reactor pressure vessel back to the core. A crucial technical problem with a recirculation pump, such as a mechanical seal indicating loss of sealing pressure, may result in a power station having to shut down for repair. The paper describes the sudden increase in stray current phenomenon leading to rapid and severe deterioration of the mechanical end face shaft seal in a reactor recirculation pump. This occurred after the installation of a variable frequency converter replacing the original motorgenerator set.

Thermodynamics of premixed combustion in a heat recirculating micro combustor

International Nuclear Information System (INIS)

Rana, Uttam; Chakraborty, Suman; Som, S.K.

2014-01-01

A thermodynamic model has been developed to evaluate exergy transfer and its destruction in the process of premixed combustion in a heat recirculating micro combustor. Exergy destruction caused by process irreversibilities is characterized by entropy generation in the process. The entropy transport equation along with the solution of temperature and species concentration fields in the wake of flame sheet assumptions have been used to determine the different components of entropy generation. The role of thermal conductivity and thickness of combustor wall, and Peclet number on transfer and destruction rate of exergy is depicted in the process of flame stabilization via heat recirculation. The entropy generations due to gas phase heat conduction and chemical reaction are identified as the major sources of exergy destruction. The total irreversibility in pre-flame region is confined only within a small distance upstream of the flame. It has been observed that the local volumetric entropy generation is higher near the axis than that near the combustor wall. The second law efficiency is almost invariant with heat loss from the combustor, Peclet number, and thermal conductivity and thickness of combustor wall. - Highlights: • Irreversibility in the combustor is mainly due to conduction and chemical reaction. • Entropy generation near the axis is higher compared to that near the wall. • Heat recirculation and process irreversibility decrease with heat loss. • The second law efficiency is almost independent of Peclet number. • Second law efficiency is almost independent of wall thermal conductivity

Constrained control of a once-through boiler with recirculation

DEFF Research Database (Denmark)

Trangbæk, K

2008-01-01

There is an increasing need to operate power plants at low load for longer periods of time. When a once-through boiler operates at a sufficiently low load, recirculation is introduced, significantly altering the control structure. This paper illustrates the possibilities for using constrained con...

Method and apparatus for control of coherent synchrotron radiation effects during recirculation with bunch compression

Science.gov (United States)

Douglas, David R; Tennant, Christopher

2015-11-10

A modulated-bending recirculating system that avoids CSR-driven breakdown in emittance compensation by redistributing the bending along the beamline. The modulated-bending recirculating system includes a) larger angles of bending in initial FODO cells, thereby enhancing the impact of CSR early on in the beam line while the bunch is long, and 2) a decreased bending angle in the final FODO cells, reducing the effect of CSR while the bunch is short. The invention describes a method for controlling the effects of CSR during recirculation and bunch compression including a) correcting chromatic aberrations, b) correcting lattice and CSR-induced curvature in the longitudinal phase space by compensating T.sub.566, and c) using lattice perturbations to compensate obvious linear correlations x-dp/p and x'-dp/p.

Review of induction linac studies

International Nuclear Information System (INIS)

Keefe, D.

1984-01-01

The three major experimental activities are as follows: (1) The Single-Beam Transport Experiment (SBTE): A quadrupole transport system consisting of 5 matching lenses and 41 identical F-D lens pairs to test the stability, or otherwise, of transport of a high-current Cs +1 beam over a long distance; (2) The Multiple-Beam Experiment (MBE): An arrangement of long-pulse induction accelerating units between which are placed multiple-beam focussing arrays to transport 16 independent beams threading the same accelerating structure. The experiment is designed to simulate on a small scale as many as possible of the features to be encountered in the HTE; and (3) The High Temperature Experiment

Heavy-Ion Fusion Accelerator Research, 1992

International Nuclear Information System (INIS)

1993-06-01

The National Energy Strategy calls for a demonstration IFE power plant by the year 2025. The cornerstone of the plan to meet this ambitious goal is research and development for heavy-ion driver technology. A series of successes indicates that the technology being studied by the HIFAR Group -- the induction accelerator -- is a prime candidate for further technology development toward this long-range goal. The HIFAR program addresses the generation of high-power, high-brightness beams of heavy ions; the understanding of the scaling laws that apply in this hitherto little-explored physics regime; and the validation of new, potentially more economical accelerator strategies. Key specific elements to be addressed include: fundamental physical limits of transverse and longitudinal beam quality; development of induction modules for accelerators, along with multiple-beam hardware, at reasonable cost; acceleration of multiple beams, merging of the beams, and amplification of current without significant dilution of beam quality; final bunching, transport, and focusing onto a small target. In 1992, the HIFAR Program was concerned principally with the next step toward a driver: the design of ILSE, the Induction Linac Systems Experiments. ILSE will address most of the remaining beam-control and beam-manipulation issues at partial driver scale. A few parameters -- most importantly, the line charge density and consequently the size of the ILSE beams -- will be at full driver scale. A theory group closely integrated with the experimental groups continues supporting present-day work and looking ahead toward larger experiments and the eventual driver. Highlights of this long-range, driver-oriented research included continued investigations of longitudinal instability and some new insights into scaled experiments with which the authors might examine hard-to-calculate beam-dynamics phenomena

Some advanced accelerator projects and ideas

International Nuclear Information System (INIS)

Sessler, A.

1987-01-01

The author discusses projects and ideas represented, as follows: The motivation is to secure high gradients to reduce power to a reasonable amount, and reduce the length as a consequence of the high gradient; a promising solution is offered by a possibility of having a free electron laser in conjunction with induction units resulting in the following steps: A free electron laser (FEL) to generate high peak power (30 GHz, 10 times the frequency at SLAC, so the wave length is one centimeter instead of ten centimeters); translate this radiation to a conventional high gradient accelerator structure, a conventional linac so that it results in stability and all the positive things known about ordinary linacs; this becomes a power source; use induction units to pump up low energy beams and accelerate little bunches of 10'' electrons up to a few hundred GeV; the schematic of such a system is exemplified with a low energy beam which is a kilo-amp of tens of MeVs; between the FEL sections, energy returns with induction units; and wave guides take rf power to a conventional linac structure - a high gradient linac structure

Increase in the Acceleration Efficiency of Solids in a Hybrid Coaxial Magnetoplasma Accelerator

Science.gov (United States)

Gerasimov, D. Yu.; Sivkov, A. A.

2018-01-01

It is shown that in a hybrid coaxial magnetoplasma accelerator with a channel length of 350 mm and a diameter of 23 mm, the acceleration velocity and the energy conversion efficiency increase as the length of the plasma structure formation channel filled with a gas-generating material decreases from 17 to 9 mm. It is found that it is reasonable to use paraffin as the gas-generating material as it has a less significant deionizing effect on the high-current arc discharge and hence causes a less significant decrease in the discharge current intensity and an increase in conductive and inductive electrodynamic forces.

The Pulse Line Ion Accelerator Concept

Energy Technology Data Exchange (ETDEWEB)

Briggs, Richard J.

2006-02-15

The Pulse Line Ion Accelerator concept was motivated by the desire for an inexpensive way to accelerate intense short pulse heavy ion beams to regimes of interest for studies of High Energy Density Physics and Warm Dense Matter. A pulse power driver applied at one end of a helical pulse line creates a traveling wave pulse that accelerates and axially confines the heavy ion beam pulse. Acceleration scenarios with constant parameter helical lines are described which result in output energies of a single stage much larger than the several hundred kilovolt peak voltages on the line, with a goal of 3-5 MeV/meter acceleration gradients. The concept might be described crudely as an ''air core'' induction linac where the PFN is integrated into the beam line so the accelerating voltage pulse can move along with the ions to get voltage multiplication.

Optical modeling of induction-linac driven free-electron lasers

International Nuclear Information System (INIS)

Scharlemann, E.T.; Fawley, W.M.

1986-01-01

The free-electron laser (FEL) simulation code FRED, developed at Lawrence Livermore National Laboratory (LLNL) primarily to model single-pass FEL amplifiers driven by induction linear accelerators, is described. The main emphasis is on the modeling of optical propagation in the laser and on the differences between the requirements for modeling rf-linac-driven vs. induction-linac-driven FELs. Examples of optical guiding and mode cleanup are presented for a 50 μm FEL

Applications of the Strategic Defense Initiative's Compact Accelerators

National Research Council Canada - National Science Library

Montanarelli, Nick

1992-01-01

...) was recently incorporated into the design of a cancer therapy unit at the Loma Linda University Medical Center, an SDI sponsored compact induction linear accelerator may replace Cobalt 60 radiation...

Engine with exhaust gas recirculation system and variable geometry turbocharger

Science.gov (United States)

Keating, Edward J.

2015-11-03

An engine assembly includes an intake assembly, an internal combustion engine defining a plurality of cylinders and configured to combust a fuel and produce exhaust gas, and an exhaust assembly in fluid communication with a first subset of the plurality of cylinders. Each of the plurality of cylinders are provided in fluid communication with the intake assembly. The exhaust assembly is provided in fluid communication with a first subset of the plurality of cylinders, and a dedicated exhaust gas recirculation system in fluid communication with both a second subset of the plurality of cylinders and with the intake assembly. The dedicated exhaust gas recirculation system is configured to route all of the exhaust gas from the second subset of the plurality of cylinders to the intake assembly. Finally, the engine assembly includes a turbocharger having a variable geometry turbine in fluid communication with the exhaust assembly.

Development of new electron beam accelerator

International Nuclear Information System (INIS)

Tanaka, Jiro

1976-01-01

Approximately two decades have elapsed since electron accelerators were first employed in industry. It is widely used in the fields of chemical and food industries and the prevention of pollution. The accelerators for industrial use are limited to those obtainable high current or high output, low cost and easy handling. The low energy (up to 2 or 3 MeV) accelerators applicable to industry include the rectification type (Cockcroft, Dynamitron, Van de Graaff etc.), the AC transformer type (resonance transformer, cascade transformer) and the transformer type. As the accelerators of higher energy (more than 3 MeV), there exist the linear accelerator and the electromagnetic induction type. The linear accelerators are widely employed for industrial and medical uses as the large output can be obtained. Though various types of accelerators are used in industry, more increasing demands in accordance with the diversification of application are not always satisfied. As it seems that the realization of a new accelerator of improved performance and cost requires long time, it may be important to perform the standardization by dividing the energy and output ranges. (Wakatsuki, Y.)

Axial electric wake field inside the induction gap exited by the intense electron beam

International Nuclear Information System (INIS)

Zhang Kaizhi; Zhang Huang; Long Jidong; Yang Guojun; He Xiaozhong; Wang Huacen

2008-01-01

While an intense electron beam passes through the accelerating gaps of a linear induction accelerator, a strong wake field will be excited. In this paper a relatively simple model is established based on the interaction between the transverse magnetic wake field and the electron beam, and the numerical calculation in succession generates a magnetic wake field distribution along the accelerator and along the beam pulse as well. The axial electric wake field is derived based on the relation between field components of a resonant mode. According to some principles in existence, the influence of this field on the high voltage properties of the induction gap is analyzed. The Dragon-I accelerator is taken as an example, and its maximum electric wake field is about 17 kV/cm, which means the effect of the wake field is noticeable. (authors)

Heavy Ion Fusion Accelerator Research (HIFAR) year-end report, April 1, 1990--September 30, 1990

International Nuclear Information System (INIS)

1990-12-01

The basic objective of the Heavy Ion Fusion Accelerator Research (HIFAR) program is to assess the suitability of heavy ion accelerators as igniters for Inertial Confinement Fusion (ICF). A specific accelerator technology, induction acceleration, is being studied at the Lawrence Berkeley Laboratory and at the Lawrence Livermore National Laboratory. The HIFAR program addresses the generation of high-power, high-brightness beams of heavy ions, the understanding of the scaling laws in this novel physics regime, and the validation of new accelerator strategies to cut costs. Key elements to be addressed include: (1) beam quality limits set by transverse and longitudinal beam physics; (2) development of induction accelerating modules, and multiple-beam hardware, at affordable costs; (3) acceleration of multiple beams with current amplification without significant dilution of the optical quality of the beams; (4) final bunching, transport, and accurate focusing on a small target

Preoperational test report, recirculation ventilation systems

Energy Technology Data Exchange (ETDEWEB)

Clifton, F.T.

1997-11-11

This represents a preoperational test report for Recirculation Ventilation Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102 and supports the ability to exhaust air from each tank. Each system consists of a valved piping loop, a fan, condenser, and moisture separator; equipment is located inside each respective tank farm in its own hardened building. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

Preoperational test report, recirculation ventilation systems

International Nuclear Information System (INIS)

Clifton, F.T.

1997-01-01

This represents a preoperational test report for Recirculation Ventilation Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102 and supports the ability to exhaust air from each tank. Each system consists of a valved piping loop, a fan, condenser, and moisture separator; equipment is located inside each respective tank farm in its own hardened building. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System

Research on high beam-current accelerators

International Nuclear Information System (INIS)

Keefe, D.

1981-01-01

In this review of research being undertaken at present in the US on accelerating devices and concepts of a novel nature, both non-collective systems, including high-current rf linacs and a variety of induction linacs, and also collective systems are considered. (U.K.)

Heavy-ion fusion accelerator research, 1988

International Nuclear Information System (INIS)

1989-05-01

This report discusses the following topics: MBE-4: The Induction-Linac Approach; Current Amplification and Acceleration Schedules; Emittance and Current Amplification; Scaling Up the Results; Progress on the Carbon-Arc Source; Injector Development; Progress Towards an ILSE Design; Beam Combination; and Focusing-System Alignment Tolerances

Recirculation zone length in renal artery is affected by flow spirality and renal-to-aorta flow ratio.

Science.gov (United States)

Javadzadegan, Ashkan; Fulker, David; Barber, Tracie

2017-07-01

Haemodynamic perturbations such as flow recirculation zones play a key role in progression and development of renal artery stenosis, which typically originate at the aorta-renal bifurcation. The spiral nature of aortic blood flow, division of aortic blood flow in renal artery as well as the exercise conditions have been shown to alter the haemodynamics in both positive and negative ways. This study focuses on the combinative effects of spiral component of blood flow, renal-to-aorta flow ratio and the exercise conditions on the size and distribution of recirculation zones in renal branches using computational fluid dynamics technique. Our findings show that the recirculation length was longest when the renal-to-aorta flow ratio was smallest. Spiral flow and exercise conditions were found to be effective in reducing the recirculation length in particular in small renal-to-aorta flow ratios. These results support the hypothesis that in renal arteries with small flow ratios where a stenosis is already developed an artificially induced spiral flow within the aorta may decelerate the progression of stenosis and thereby help preserve kidney function.

Study of atmospheric stagnation, recirculation, and ventilation potential at Narora Atomic Power Station site

International Nuclear Information System (INIS)

Kumar, Deepak; Kumar, Avinash; Kumar, Vimal; Rao, K.S.; Kumar, Jaivender; Ravi, P.M.

2011-01-01

Atmosphere is an important pathway to be considered in assessment of the environmental impact of radioactivity releases from nuclear facilities. Estimation of concentration of released effluents in air and possible ground contamination needs an understanding of relevant atmospheric dispersion. This article describes the meteorological characteristics of Narora Atomic Power Station (NAPS) site by using the integral parameters developed by Allwine and Whiteman. Meteorological data measured during the period 2006-2010 were analyzed. The integral quantities related to the occurrence of stagnation, recirculation, and ventilation characteristics were studied for NAPS site to assess the dilution potential of the atmosphere. Wind run and recirculation factors were calculated for a 24-h transport time using 5 years of hourly surface measurements of wind speed and direction. The occurrence of stagnation, recirculation, and ventilation characteristics during 2006-2010 at NAPS site is observed to be 33.8% of the time, 19.5% of the time, and 34.7% of the time, respectively. The presence of strong winds with predominant wind direction NW and WNW during winter and summer seasons leads to higher ventilation (48.1% and 44.3%) and recirculation (32.6% of the summer season). The presence of light winds and more dispersed winds during prewinter season with predominant wind directions W and WNW results in more stagnation (59.7% of the prewinter season). Thus, this study will serve as an essential meteorological tool to understand the transport mechanism of atmospheric radioactive effluent releases from any nuclear industry. (author)

Human skin is protected by four functionally and phenotypically discrete populations of resident and recirculating memory T cells

NARCIS (Netherlands)

Watanabe, Rei; Gehad, Ahmed; Yang, Chao; Scott, Laura L.; Teague, Jessica E.; Schlapbach, Christoph; Elco, Christopher P.; Huang, Victor; Matos, Tiago R.; Kupper, Thomas S.; Clark, Rachael A.

2015-01-01

The skin of an adult human contains about 20 billion memory T cells. Epithelial barrier tissues are infiltrated by a combination of resident and recirculating T cells in mice, but the relative proportions and functional activities of resident versus recirculating T cells have not been evaluated in

FROZEN ASH BERRIES PROCESSING IN THE DEVICE WITH A NOZZLE CONTINUOUS VIBRATION, EQUIPPED WITH AN EXTERNAL RECIRCULATION LOOP

Directory of Open Access Journals (Sweden)

P. P. Ivanov

2015-01-01

Full Text Available An external recirculation loop was used as the method of increasing the concentration of dry soluble substances in the obtained extract. The objective of the research is to determine the value of the external recirculation index (KR, which provides the optimal conditions for the process carrying out. The results of the conducted research show the increase in the concentration of dry soluble substances in the extract if the external recirculation index increases. It is conditioned by the extension of the interaction between the processed raw mate-rial and the extract, as well as by the decrease in the surface tension of the extracting agent, which results in improving the conditions of its penetration into the pores of particles. Such an opposite property of recirculation as the decrease in mass transfer rate was also ob-served. It causes the significant rise of dry soluble substances losses while discharging extraction cake, which leads to the performance degradation. According to the analytical evaluation of the obtained results, the maximum process results are observed if KR = 1 (without recirculation and KR = 2, the values of the optimality criterion are 5.02∙10-3 and 4.92∙10-3 % mass/W respectively. At the same time the operation of the apparatus with the recirculation loop at KR = 2 is characterized by 62%-increase in dry soluble substances concentration in the extract as compared to a pure extracting agent. The efficiency of recirculation at KR = 2 is proved by the saving of energy con-sumed on the evaporation of the extract obtained. The energy costs calculation for the production of 60l of 12 % mass dry soluble sub-stances concentration extract showed that if the initial dry soluble substances concentration is raised to 6 % mass (KR = 2, the amount of consumed saturated vapor is 104.1 kg less, which is 281685 kJ if the vapor specific enthalpy is 2706.29 kJ/kg.

Numerical analysis and control of the recirculation bubble strength ...

African Journals Online (AJOL)

Numerical investigation of the turbulent jet flows, both central and annular type of jets has been carried out with the introduction of swirl at the inlet using the modified κ −ε model. It was observed that the recirculation bubble generated by the central jet without swirl diminishes in size due to increase in swirl number, while in ...

Cost Characteristics of the African Catfish Culture in Recirculating ...

African Journals Online (AJOL)

Cost Characteristics of the African Catfish Culture in Recirculating Production Facilities in Ibadan, Oyo State, Nigeria. ... Food Conversion Ratio also ranged from 0.60–0.78 for fingerlings, 1.01-‐ 2.08 for juveniles and 1.15-‐1.68 for grow out system. In all cases, variable cost accounts for more than 75% of total cost.

NUTRIENTS DYNIMIC IN AN AQUAPONIC RECIRCULATING SYSTEM FOR STURGEON AND LETTUCE (LACTUCA SATIVA PRODUCTION

Directory of Open Access Journals (Sweden)

LORENA SFETCU

2008-10-01

Full Text Available Aquaponics are modern production systems, which integrate the aquaculture technology with hydroponic systems (vegetable production without soil with a goal of fructification of residual nutrients resulted from metabolic activity of fish biomass as high quality vegetable biomass sealable as ecological products. In the present study, as a first step in aquaponic recirculating systems evaluation, the authors aim to compare two types of recirculating systems: classical (hereby noted with RAS and integrated/aquaponic (RAS_A regarding water quality parameters generally, and TAN (total ammonia nitrogen production and transformation, particularly.

Particle capture by turbulent recirculation zones measured using long-time Lagrangian particle tracking

Energy Technology Data Exchange (ETDEWEB)

Siu, Y.W. [Hong Kong Securities Institute, Department of Professional Education and Training, Central (China); Taylor, A.M.K.P. [Imperial College London, Department of Mechanical Engineering, London (United Kingdom)

2011-07-15

We have measured the trajectories of particles into, and around, the recirculation zone formed in water flowing through a sudden pipe expansion with radius ratio 1:3.7, at Reynolds numbers between 5,960 and 41,700 over a range of particle Stokes number (here defined as St=(T{sub f})/({tau} p), where T{sub f} is an appropriate mean or turbulent timescale of the fluid flow and a particle relaxation time, {tau}{sub p},) between 6.2 and 51 and drift parameter between 0.3 and 2.8. The particles were thus weakly inertial but nevertheless heavy with a diameter about an order of magnitude larger than the Kolmogorov scale. Trajectories of particles, released individually into the flow, were taken in a Lagrangian framework by a three-dimensional particle tracking velocimeter using a single 25 Hz framing rate intensified CCD camera. Trajectories are quantified by the axial distribution of the locations of particle axial velocity component reversal and the probability distributions of trajectory angle and curvature. The effect of increasing the drift parameter was to reduce the tendency for particles to enter the recirculation zone. For centreline release, the proportion of particles entering the recirculation zone and acquiring a negative velocity decreased from about 80% to none and from about 66% to none, respectively, as the drift parameter increased from 0.3 to 2.8. Almost half of the particles experienced a relatively large change of direction corresponding to a radius of curvature of their trajectory comparable to, or smaller than, the radius of the downstream pipe. This was due to the interaction between these particles and eddies of this size in the downstream pipe and provides experimental evidence that particles are swept by large eddies into the recirculation zone over 1.0 < Z{sup *} < 2.5, where Z{sup *} is axial distance from the expansion plane normalized by the downstream pipe diameter, which was well upstream of the reattachment point at the wall (Z

Reactor recirculation pump test loop

International Nuclear Information System (INIS)

Taka, Shusei; Kato, Hiroyuki

1979-01-01

A test loop for a reactor primary loop recirculation pumps (PLR pumps) has been constructed at Ebara's Haneda Plant in preparation for production of PLR pumps under license from Byron Jackson Pump Division of Borg-Warner Corporation. This loop can simulate operating conditions for test PLR pumps with 130 per cent of the capacity of pumps for a 1100 MWe BWR plant. A main loop, primary cooling system, water demineralizer, secondary cooling system, instrumentation and control equipment and an electric power supply system make up the test loop. This article describes the test loop itself and test results of two PLR pumps for Fukushima No. 2 N.P.S. Unit 1 and one main circulation pump for HAZ Demonstration Test Facility. (author)

Heavy Ion Fusion Accelerator Research (HIFAR) year-end report, April 1--September 30, 1988

International Nuclear Information System (INIS)

1988-12-01

The basic objective of the Heavy Ion Fusion Accelerator Research (HIFAR) program is to assess the suitability of heavy ion accelerators as igniters for Inertial Confinement Fusion (ICF). A specific accelerator technology, the induction linac, has been studied at the Lawrence Berkeley Laboratory and has reached the point at which its viability for ICF applications can be assessed over the next few years. The HIFAR program addresses the generation of high power, high-brightness beams of heavy ions, the understanding of the scaling laws in this novel physics regime, and the validation of new accelerator strategies, to cut costs. Key elements to be addressed include: beam quality limits set by transverse and longitudinal beam physics; development of induction accelerating modules, and multiple-beam hardware, at affordable costs; acceleration of multiple beams with current amplification --both new features in a linac -- without significant dilution of the optical quality of the beams; final bunching, transport, and accurate focusing on a small target

Continuous hydrothermal co-liquefaction of aspen wood and glycerol with water phase recirculation

DEFF Research Database (Denmark)

Pedersen, Thomas H.; Grigoras, Ionela F.; Hoffmann, Julia

2016-01-01

heating value of 34.3 MJ/kg. The volatile fraction of the biocrude consisted mostly of compounds having number of carbon atoms in the C6–C12 range similar to gasoline. In terms of process feasibility, it was revealed that total organic carbon (TOC) and ash significantly accumulated in the water phase when...... such is recirculated for the proceeding batch. After four batches the TOC and the ash mass fraction of the water phase were 136.2 [g/L] and 12.6 [%], respectively. Water phase recirculation showed a slight increase in the biocrude quality in terms on an effective hydrogen-to-carbon ratio, but it showed no effects...

Characterising organic matter in recirculating aquaculture systems with fluorescence EEM spectroscopy

DEFF Research Database (Denmark)

Hambly, Adam; Arvin, Erik; Pedersen, Lars-Flemming

2015-01-01

The potential of recirculating aquaculture systems (RAS) in the aquaculture industry is increasingly being acknowledged. Along with intensified application, the need to better characterise and understand the accumulated dissolved organic matter (DOM) within these systems increases. Mature RASs...

Control methodologies based on geothermal recirculating aquaculture system

International Nuclear Information System (INIS)

Farghally, Hanaa M.; Atia, Doaa M.; El-madany, Hanaa T.; Fahmy, Faten H.

2014-01-01

One of the most common uses of geothermal heat is in RAS (recirculation aquaculture systems) where the water temperature is accurately controlled for optimum growing conditions for sustainable and intensive rearing of marine and freshwater fish. This paper presents a design for RAS rearing tank and plate type heat exchanger to be used with geothermal energy as a source of heating water. A well at Umm Huweitat on the Red Sea is used as a source of geothermal energy. The heat losses from the RAS tank are calculated using Geo Heat Center Software. Then a plate type heat exchanger is designed using the epsilon–NTU (number of transfer units) analysis method. For optimal growth and abundance of production, a different techniques of control system are applied to control the water temperature. The total system is built in MATLAB/SIMULINK to study the overall performance of control unit. Finally, a comparison between PI, Fuzzy-PID, and Fuzzy Logic Control has been done. - Highlights: • Design recirculating aquaculture system using geothermal energy. • Design a PI controller for water temperature control. • Design a Fuzzy logic controller for water temperature control. • Design a Fuzzy-PID controller for water temperature control. • Comparison between different control systems

Method of correcting eddy current magnetic fields in particle accelerator vacuum chambers

Science.gov (United States)

Danby, Gordon T.; Jackson, John W.

1991-01-01

A method for correcting magnetic field aberrations produced by eddy currents induced in a particle accelerator vacuum chamber housing is provided wherein correction windings are attached to selected positions on the housing and the windings are energized by transformer action from secondary coils, which coils are inductively coupled to the poles of electro-magnets that are powered to confine the charged particle beam within a desired orbit as the charged particles are accelerated through the vacuum chamber by a particle-driving rf field. The power inductively coupled to the secondary coils varies as a function of variations in the power supplied by the particle-accelerating rf field to a beam of particles accelerated through the vacuum chamber, so the current in the energized correction coils is effective to cancel eddy current flux fields that would otherwise be induced in the vacuum chamber by power variations in the particle beam.

Influence of recirculation rate on the performance of a combined ...

African Journals Online (AJOL)

The objective of this study was to evaluate a combined anaerobic-aerobic upflow fixed-bed reactor with liquid phase recirculation for the removal of nitrogen and organic matter from poultry slaughterhouse wastewater. The reactor performance was evaluated with a hydraulic retention time (HRT) of 11 h and three different ...

Preliminary design study of pebble bed reactor HTR-PM base using once-through-then-out fuel recirculation

International Nuclear Information System (INIS)

Topan Setiadipura; Jupiter S Pane; Zuhair

2016-01-01

Pebble Bed Reactor (PBR) is one of the advanced reactor type implementing strong passive safety feature. In this type of design has the potential to do a cogeneration useful for the treatment of various minerals in various islands in Indonesia. The operation of the PBR can be simplified by implementing once-through-then-out (OTTO) fuel recirculation scheme in which pebble fuel only pass the core once time. The purpose of this research is to understand quantitative influence of the changing of fuel element recirculation on the PBR core performance and to find preliminary optimization design of PBR type reactor with OTTO recirculation scheme. PEBBED software was used to find PBR equilibrium core. The calculation result gives quantitative data on the impact of implementing a different fuel recirculation, especially using OTTO scheme. Furthermore, an early optimized PBR design based on HTR-PM using OTTO scheme was obtained where the power must be downgraded into 115 MWt in order to preserve the safety feature. The simplicity of the reactor operation and the reduction of reactor component with OTTO scheme still make this early optimized design an interesting alternative design, despite its power reduction from the reference design. (author)

Resolution of issues related to alternative RCS injection in the absence of containment sump recirculation

International Nuclear Information System (INIS)

Charles L Kling; Stephen S Barshay; Mathew C Jacob; Michael J Friedman

2005-01-01

Full text of publication follows: On June 9, 2003 the US NRC issued Bulletin No. 2003-01 that deals with the potential impact of debris blockage on containment sump recirculation at PWRs during a Loss-of-Coolant Accident (LOCA). In response to the bulletin, the Omaha Public Power District (OPPD) is in the process of developing procedural and operational strategies for their Fort Calhoun Station (FCS) to address the issues raised. Westinghouse provided engineering support to OPPD in identifying and resolving issues related to alternative means of supplying safety injection water to the reactor coolant system (RCS) in the absence of containment sump recirculation. Nuclear power plants are designed to protect the core following a LOCA by providing a continuous supply of cooling water to the core. In the long term, the Refueling Water Storage Tank (RWST) inventory will be depleted and core heat removal accomplished via recirculation of water previously injected into the Reactor Coolant System (RCS) and collected in the containment sump. Debris generated within the containment as a result of the impingement of fluid jets in the Zone of Influence (ZOI) of the RCS break and containment wash down may find its way into the containment sump. As the safety injection pumps take suction from the sump, in the recirculation mode of operation, the debris suspended in the sump water could begin to accumulate in the sump screen that is located in the recirculation path. Should sufficient debris accumulate on the sump screen, a flow blockage could potentially develop. This would result in insufficient safety injection pump NPSH, thereby impairing the recirculation mode of injection into RCS. Potential debris blockage and prevention of sump recirculation may be addressed by refilling the RWST with water and injecting this water directly into the core. This paper identifies and attempts to resolve several issues related to this alternative mode of RCS injection. In particular, the

Molecular Adsorbent Recirculating System Can Reduce Short-Term Mortality Among Patients With Acute-on-Chronic Liver Failure-A Retrospective Analysis.

Science.gov (United States)

Gerth, Hans U; Pohlen, Michele; Thölking, Gerold; Pavenstädt, Hermann; Brand, Marcus; Hüsing-Kabar, Anna; Wilms, Christian; Maschmeier, Miriam; Kabar, Iyad; Torner, Josep; Pavesi, Marco; Arroyo, Vicente; Banares, Rafael; Schmidt, Hartmut H J

2017-10-01

Acute-on-chronic liver failure is associated with numerous consecutive organ failures and a high short-term mortality rate. Molecular adsorbent recirculating system therapy has demonstrated beneficial effects on the distinct symptoms, but the associated mortality data remain controversial. Retrospective analysis of acute-on-chronic liver failure patients receiving either standard medical treatment or standard medical treatment and molecular adsorbent recirculating system. Secondary analysis of data from the prospective randomized Recompensation of Exacerbated Liver Insufficiency with Hyperbilirubinemia and/or Encephalopathy and/or Renal Failure trial by applying the recently introduced Chronic Liver Failure-criteria. Medical Departments of University Hospital Muenster (Germany). This analysis was conducted in two parts. First, 101 patients with acute-on-chronic liver failure grades 1-3 and Chronic Liver Failure-C-Organ Failure liver subscore equals to 3 but stable pulmonary function were identified and received either standard medical treatment (standard medical treatment, n = 54) or standard medical treatment and molecular adsorbent recirculating system (n = 47) at the University Hospital Muenster. Second, the results of this retrospective analysis were tested against the Recompensation of Exacerbated Liver Insufficiency with Hyperbilirubinemia and/or Encephalopathy and/or Renal Failure trial. Standard medical treatment and molecular adsorbent recirculating system. Additionally to improved laboratory variables (bilirubin and creatinine), the short-term mortality (up to day 14) of the molecular adsorbent recirculating system group was significantly reduced compared with standard medical treatment. A reduced 14-day mortality rate was observed in the molecular adsorbent recirculating system group (9.5% vs 50.0% with standard medical treatment; p = 0.004), especially in patients with multiple organ failure (acute-on-chronic liver failure grade 2-3). Concerning the

Virtual gap dielectric wall accelerator

Science.gov (United States)

Caporaso, George James; Chen, Yu-Jiuan; Nelson, Scott; Sullivan, Jim; Hawkins, Steven A

2013-11-05

A virtual, moving accelerating gap is formed along an insulating tube in a dielectric wall accelerator (DWA) by locally controlling the conductivity of the tube. Localized voltage concentration is thus achieved by sequential activation of a variable resistive tube or stalk down the axis of an inductive voltage adder, producing a "virtual" traveling wave along the tube. The tube conductivity can be controlled at a desired location, which can be moved at a desired rate, by light illumination, or by photoconductive switches, or by other means. As a result, an impressed voltage along the tube appears predominantly over a local region, the virtual gap. By making the length of the tube large in comparison to the virtual gap length, the effective gain of the accelerator can be made very large.

Instrument for the measuring magnetic field characteristics of induction acceleration

International Nuclear Information System (INIS)

Novikov, V.M.; Romasheva, P.I.

1976-01-01

An instrument for the measuring instantaneous values of variable and pulsed magnetic fields with an amplitide of 0.005-2.0 and duration of 5x10 -6 -2x10 -2 sec is described. Time resolution is not less than 0.5 musec, measuring accuracy is about 1%. Induction coils are used as sensors. A digital voltmeter serves as a secondary recorder

Use of planted biofilters in integrated recirculating aquaculture-hydroponics systems in the Mekong Delta, Vietnam

DEFF Research Database (Denmark)

Trang, N.T.D.; Brix, Hans

2014-01-01

The feasibility of using planted biofilters for purification of recirculated aquaculture water in the Mekong Delta of Vietnam was assessed. The plant trenches were able to clean tilapia aquaculture water and to maintain good water quality in the fish tanks without renewal of the water. NH4-N was ...... rates of 725 kg N and 234 kg P ha-1 year-1. This research demonstrates that integrated recirculating aquaculture-hydroponics (aquaponics) systems provide significant water savings and nutrient recycling as compared with traditional fish ponds....

The accumulation of substances in Recirculating Aquaculture Systems (RAS) affects embryonic and larval development in common carp Cyprinus carpio

NARCIS (Netherlands)

Martins, C.I.; Pristin, M.G.; Ende, S.S.W.; Eding, E.H.; Verreth, J.A.J.

2009-01-01

The accumulation of substances in Recirculating Aquaculture Systems (RAS) may impair the growth and welfare of fish. To test the severity of contaminants accumulated in RAS, early-life stages of fish were used. Ultrafiltered water from two Recirculating Aquaculture Systems (RAS), one RAS with a high

Laser-plasma booster for ion post acceleration

Directory of Open Access Journals (Sweden)

Satoh D.

2013-11-01

Full Text Available A remarkable ion energy increase is demonstrated for post acceleration by a laser-plasma booster. An intense short-pulse laser generates a strong current by high-energy electrons accelerated, when this intense short-pulse laser illuminates a plasma target. The strong electric current creates a strong magnetic field along the high-energy electron current in plasma. During the increase phase in the magnetic field, a longitudinal inductive electric field is induced for the forward ion acceleration by the Faraday law. Our 2.5-dimensional particle-in-cell simulations demonstrate a remarkable increase in ion energy by several tens of MeV.

Turbulent characteristics of shear-thinning fluids in recirculating flows

Energy Technology Data Exchange (ETDEWEB)

Pereira, A.S. [Inst. Superior de Engenharia do Porto (Portugal). Dept. de Engenharia Quimica; Pinho, F.T. [Centro de Estudos de Fenomenos de Transporte, Departamento de Engenharia Mecanica e Gestao Industrial, Faculdade de Engenharia da Universidade do Porto, Rua dos Bragas, 4050-123 Porto (Portugal)

2000-03-01

A miniaturised fibre optic laser-Doppler anemometer was used to carry out a detailed hydrodynamic investigation of the flow downstream of a sudden expansion with 0.1-0.2% by weight shear-thinning aqueous solutions of xanthan gum. Upstream of the sudden expansion the pipe flow was fully-developed and the xanthan gum solutions exhibited drag reduction with corresponding lower radial and tangential normal Reynolds stresses, but higher axial Reynolds stress near the wall and a flatter axial mean velocity profile in comparison with Newtonian flow. The recirculation bubble length was reduced by more than 20% relative to the high Reynolds number Newtonian flow, and this was attributed to the occurrence further upstream of high turbulence for the non-Newtonian solutions, because of advection of turbulence and earlier high turbulence production in the shear layer. Comparisons with the measurements of Escudier and Smith (1999) with similar fluids emphasized the dominating role of inlet turbulence. The present was less anisotropic, and had lower maximum axial Reynolds stresses (by 16%) but higher radial turbulence (20%) than theirs. They reported considerably longer recirculating bubble lengths than we do for similar non-Newtonian fluids and Reynolds numbers. (orig.)

Adoption of Recirculating Aquaculture Systems in Pangasius Farms: A Choice Experiment

NARCIS (Netherlands)

Pham, T.A.N.; Gielen-Meuwissen, M.P.M.; Le, T.T.; Bosma, R.H.; Oude Lansink, A.G.J.M.

2015-01-01

A growing number of European customers’ demands certified pangasius such as ASC in order to ensure sustainable production. Implementing Recirculating Aquaculture Systems (RAS) contributes to an improved water quality, a key issue in achieving ASC certification. This study uses a choice experiment to

Steroids accumulate in the rearing water of commercial recirculating aquaculture systems

NARCIS (Netherlands)

Mota, V.C.; Martins, C.I.; Eding, E.H.; Canário, A.V.M.; Verreth, J.A.J.

2014-01-01

Little information is available on steroid concentrations in the rearing water of aquaculture systems and whether they accumulate in recirculating aquaculture systems (RAS). Therefore this study aimed at determining (1) the concentrations and variation of cortisol and sex steroids in RAS, (2) the

BWR series pump recirculation system

International Nuclear Information System (INIS)

Dillmann, C.W.

1992-01-01

This patent describes a recirculation system for driving reactor coolant water contained in an annular downcomer defined between a boiling water reactor vessel and a reactor core spaced radially inwardly therefrom. It comprises a plurality of circumferentially spaced second pumps disposed in the downcomer, each including an inlet for receiving from the downcomer a portion of the coolant water as pump inlet flow, and an outlet for discharging the pump inlet flow pressurized in the second pump as pump outlet flow; and means for increasing pressure of the pump inlet flow at the pump inlet including a first pump disposed in series flow with the second pump for first receiving the pump inlet flow from the downcomer and discharging to the second pump inlet flow pressurized in the first pump

Heavy Ion Fusion Accelerator Research (HIFAR) half-year report, October 1, 1988--March 31, 1989

International Nuclear Information System (INIS)

1989-06-01

The basic objective of the Heavy Ion Fusion Accelerator Research (HIFAR) program is to assess the suitability of heavy ion accelerators as igniters for Inertial Confinement Fusion (ICF). A specific accelerator technology, the induction linac, has been studied at the Lawrence Berkeley Laboratory and has reached the point at which its viability for ICF applications can be assessed over the next few years. The HIFAR program addresses the generation of high-power, high-brightness beams of heavy ions, the understanding of the scaling laws in this novel physics regime, and the validation of new accelerator strategies, to cut costs. Key elements to be addressed include: beam quality limits set by transverse and longitudinal beam physics; development of induction accelerating modules, and multiple-beam hardware, at affordable costs; acceleration of multiple beams with current amplification --both new features in a linac -- without significant dilution of the optical quality of the beams; and final bunching, transport, and accurate focusing on a small target

Heavy Ion Fusion Accelerator Research (HIFAR) year-end report, October 1, 1987--March 31, 1988

International Nuclear Information System (INIS)

1988-06-01

The basic objective of the Heavy Ion Fusion Accelerator Research (HIFAR) program is to assess the suitability of heavy ion accelerators as igniters for Inertial Confinement Fusion (ICF). A specific accelerator technology, the induction linac, has been studied at Lawrence Berkeley Laboratory and has reached the point at which its viability for ICF applications can be assessed over the next few years. The HIFAR program addresses the generation of high-power, high-brightness beams of heavy ions, the understanding of the scaling laws in this novel physics regime, and the validation of new accelerator strategies, to cut costs. Key elements to be addressed include: beam quality limits set by transverse and longitudinal beam physics; development of induction accelerating modules, and multiple-beam hardware, at affordable costs; acceleration of multiple beams with current amplification -- both new features in a linac -- without significant dilution of the optical quality of beams; and final bunching, transport, and accurate focusing on a small target

Experimental studies of impact of exhaust gas recirculation on the ...

African Journals Online (AJOL)

This paper considers the problem of reducing the nitrogen oxides emissions in exhaust gases (EG) of diesel engine by exhaust gas recirculation (EGR). Based on the carried out study the influence of EGR on technical-and-economic and environmental performance of a diesel engine was found as well as main directions of ...

Dietary carbohydrates and denitrification in recirculating aquaculture systems

OpenAIRE

Meriac, A.

2014-01-01

Due to overfishing of global fish stocks and increasing fish meal prices, plant ingredients are being increasingly used as an alternative source of protein in fish feeds. However, the inclusion of unpurified plant ingredients will also increase the content of fibers in feeds. Fibers are nearly indigestible and will therefore increase solid waste production in aquaculture. This solid waste can be used to as a carbon source for denitrification to control nitrate levels in recirculating aquacul...

Tracking studies in eRHIC energy-recovery recirculator

Energy Technology Data Exchange (ETDEWEB)

Meot, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Brooks, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ptitsyn, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Trbojevic, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tsoupas, N. [Brookhaven National Lab. (BNL), Upton, NY (United States)

2015-07-13

Beam and polarization tracking studies in eRHIC energy recovery electron recirculator are presented, based on a very preliminary design of the FFAG lattice. These simulations provide examples of some of the beam and spin optics aspects of the linear FFAG lattice concept and its application in eRHIC, they provide code benchmarking for synchrotron radiation and spin diffusion in addition, and pave the way towards end-to-end 6-D(phasespace)+3D(spin) tracking simulations.

Review of induction linac studies

International Nuclear Information System (INIS)

Keefe, Denis

1984-01-01

The major emphasis of the U.S. program in Heavy Ion Fusion Accelerator Research is on developing and understanding induction-linac systems that employ multiple beams of high-current heavy ions. The culmination of the plan lies in building the High Temperature Experiment (HTE) which will involve an ion induction linac to deliver multiple high current beams, that can be focussed and overlapped on a two-millimeter diameter spot. A sequence of three major experimental activities are as follows. In the Single-Beam Transport Experiment (SBTE), the stability or otherwise transport of a high-current Cs +1 beam over a long distance is tested. In the Multiple-Beam Experiment (MBE), the experiment is designed to simulate on a small scale as many as possible of the features to be encountered in the HTE. (Mori, K.)

The tandem betatron accelerator

International Nuclear Information System (INIS)

Keinigs, R.

1991-01-01

This paper reports that the tandem betatron is a compact, high-current induction accelerator that has the capability to accelerate electrons to an energy of order one gigavolt. Based upon the operating principle of a conventional betatron, the tandem betatron employs two synchronized induction cores operating 180 degrees out of phase. Embedded within the cores are the vacuum chambers, and these are connected by linear transport sections to allow for moving the beam back and forth between the two betatrons. The 180 degree phase shift between the core fluxes permits the circumvention of the flux swing constraint that limits the maximum energy gain of a conventional betatron. By transporting the beam between the synchronized cores, an electron can access more than one acceleration cycle, and thereby continue to gain energy. This added degree of freedom also permits a significant decrease in the size of the magnet system. Biasing coils provide independent control of the confining magnetic field. Provided that efficient beam switching can be performed, it appears feasible that a one gigavolt electron beam can be generated and confined. At this energy, a high current electron beam circulating in a one meter radius orbit could provide a very intense source of short wavelength (λ < 10 nm) synchrotron radiation. This has direct application to the emerging field of x-ray lithography. At more modest energies (10 MeV-30 MEV) a compact tandem betatron could be employed in the fields of medical radiation therapy, industrial radiography, and materials processing

A New Eulerian Model for Turbulent Evaporating Sprays in Recirculating Flows

NARCIS (Netherlands)

Wittig, S.; Hallmann, M.; Scheurlen, M.; Schmehl, R.

1993-01-01

A new Eulerian model for the computation of turbulent evaporating sprays in recirculating flows is derived. It comprises droplet heating and evaporation processes by solving separate transport equations for the droplet's temperature and diameter. Full coupling of the droplet and the gaseous phase is

The last large pelletron accelerator of the Herb era

International Nuclear Information System (INIS)

Chopra, S.; Narayanan, M. M.; Joshi, R.; Gargari, S.; Kanjilal, D.; Datta, S. K.; Mehta, G. K.

1999-01-01

Prof. Ray Herb pioneered the concept and design of the tandem Pelletron accelerator in the late sixties at NEC. The 15UD Pelletron at Nuclear Science Centre (NSC), upgraded for 16MV operation using compressed geometry accelerating tubes is the last such large Pelletron. It has unique features like offset and matching quadrupoles after the stripper for charge state selection inside the high voltage terminal and consequently the option of further stripping the ion species of the selected charge states at high energy dead section, and elaborate pulsing system in the pre-acceleration region consisting of a beam chopper, a travelling wave deflector, a light ion buncher (1-80 amu) and a heavy ion buncher (>80 amu). NSC was established as a heavy ion accelerator based inter university centre in 1985. It became operational in July 1991 to cater to the research requirements of a large user community which at present includes about fifty universities, twenty-eight colleges and a dozen other academic institutes and research laboratories. The number of users in Materials and allied sciences is about 500. Various important modifications have been made to improve the performance of the accelerator in the last seven years. These include replacement of the corona voltage grading system by a resistor based one, a pick-up loop to monitor charging system performance, conversion from basic double unit structure to singlet, installation of a spiral cavity based phase detector system with post-accelerator stripper after the analyzing magnet, and a high efficiency multi harmonic buncher. Installation of a turbo pump based stripper gas recirculation system in the terminal is also planned. A brief description of utilization of the machine will be given

Continuous hydroponic wheat production using a recirculating system

Science.gov (United States)

Mackowiak, C. L.; Owens, L. P.; Hinkle, C. R.; Prince, R. P.

1989-01-01

Continuous crop production, where plants of various ages are growing simultaneously in a single recirculating nutrient solution, is a possible alternative to batch production in a Controlled Ecological Life Support System. A study was conducted at John F. Kennedy Space Center where 8 trays (0.24 sq m per tray) of Triticum aestivum L. Yecora Rojo were grown simultaneously in a growth chamber at 23 C, 65 percent relative humidity, 1000 ppm CO2, continuous light, with a continuous flow, thin film nutrient delivery system. The same modified Hoagland nutrient solution was recirculated through the plant trays from an 80 L reservoir throughout the study. It was maintained by periodic addition of water and nutrients based on chemical analyses of the solution. The study was conducted for 216 days, during which 24 trays of wheat were consecutively planted (one every 9 days), 16 of which were grown to maturity and harvested. The remaining 8 trays were harvested on day 216. Grain yields averaged 520 g m(exp -2), and had an average edible biomass of 32 percent. Consecutive yields were unaffected by nutrient solution age. It was concluded that continual wheat production will work in this system over an extended period of time. Certain micronutrient deficiencies and toxicities posed problems and must be addressed in future continuous production systems.

Ion sources for medical accelerators

Science.gov (United States)

Barletta, W. A.; Chu, W. T.; Leung, K. N.

1998-02-01

Advanced injector systems for proton synchrotrons and accelerator-based boron neutron capture therapy systems are being developed at the Lawrence Berkeley National Laboratory. Multicusp ion sources, particularly those driven by radio frequency, have been tested for these applications. The use of a radio frequency induction discharge provides clean, reliable, and long-life source operation. It has been demonstrated that the multicusp ion source can provide good-quality positive hydrogen ion beams with a monatomic ion fraction higher than 90%. The extractable ion current densities from this type of source can meet the injector requirements for both proton synchrotron and accelerator-based boron neutron capture therapy projects.

Technology of magnetically driven accelerators

International Nuclear Information System (INIS)

Brix, D.L.; Hawkins, S.A.; Poor, S.E.; Reginato, L.L.; Smith, M.W.

1985-01-01

The marriage of Induction Linac technology with Nonlinear Magnetic Modulators has produced some unique capabilities. It appears possible to produce electron beams with average currents measured in amperes, at gradients exceeding 1 MeV/meter, and with power efficiencies approaching 50%. A 2 MeV, 5 kA electron accelerator has been constructed at the Lawrence Livermore National Laboratory (LLNL) to demonstrate these concepts and to provide a test facility for high brightness sources. The pulse drive for the accelerator is based on state-of-the-art magnetic pulse compressors with very high peak power capability, repetition rates exceeding a kilohertz and excellent reliability

Technology of magnetically driven accelerators

International Nuclear Information System (INIS)

Birx, D.L.; Hawkins, S.A.; Poor, S.E.; Reginato, L.L.; Smith, M.W.

1985-01-01

The marriage of Induction Linac technology with Nonlinear Magnetic Modulators has produced some unique capabilities. It appears possible to produce electron beams with average currents measured in amperes, at gradients exceeding 1 MeV/meter, and with power efficiencies approach 50%. A 2 MeV, 5 kA electron accelerator has been constructed at the Lawrence Livermore National Laboratory (LLNL) to demonstrate these concepts and to provide a test facility for high brightness sources. The pulse drive for the accelerator is based on state-of-the-art magnetic pulse compressors with very high peak power capability, repetition rates exceeding a kilohertz and excellent reliability

Control Infrastructure for a Pulsed Ion Accelerator

International Nuclear Information System (INIS)

Persaud, A.; Regis, M. J.; Stettler, M. W.; Vytla, V. K.

2016-01-01

We report on updates to the accelerator controls for the Neutralized Drift Compression Experiment II, a pulsed induction-type accelerator for heavy ions. The control infrastructure is built around a LabVIEW interface combined with an Apache Cassandra backend for data archiving. Recent upgrades added the storing and retrieving of device settings into the database, as well as ZeroMQ as a message broker that replaces LabVIEW's shared variables. Converting to ZeroMQ also allows easy access via other programming languages, such as Python.

Control Infrastructure for a Pulsed Ion Accelerator

Science.gov (United States)

Persaud, A.; Regis, M. J.; Stettler, M. W.; Vytla, V. K.

2016-10-01

We report on updates to the accelerator controls for the Neutralized Drift Compression Experiment II, a pulsed induction-type accelerator for heavy ions. The control infrastructure is built around a LabVIEW interface combined with an Apache Cassandra backend for data archiving. Recent upgrades added the storing and retrieving of device settings into the database, as well as ZeroMQ as a message broker that replaces LabVIEW's shared variables. Converting to ZeroMQ also allows easy access via other programming languages, such as Python.

Implementation of multiple measures to improve reactor recirculation pump sealing performance in nuclear boiling water reactor service

Energy Technology Data Exchange (ETDEWEB)

Loenhout, Gerard van [Flowserve B.V., Etten-Leur (Netherlands). Nuclear Services and Solutions Engineering; Hurni, Juerg

2015-05-15

A modern reactor recirculation pump circulates a large volume of high temperature, very pure water from the reactor pressure vessel back to the core by feeding into multiple stationary jet pumps inside the vessel. Together with the jet pumps, they allow station operators to vary coolant flow and variable pump speed provides the best and most stable reactor power control. A crucial technical problem with a recirculation pump, such as a mechanical seal indicating loss of sealing pressure, may result in a power station having to shut down for repair. This article describes the sudden increase in stray current phenomenon leading to rapid and severe deterioration of the mechanical end face shaft seal in a reactor recirculation pump. This occurred after the installation of a variable frequency converter replacing the original motor-generator set. This article will also discuss the 2,500 hour laboratory test results conducted under reactor recirculation pump sealing conditions using a newly developed seal face technology recently implemented to overcome challenges when sealing neutral, ultra-pure water. In addition, the article will describe the elaborate shaft grounding arrangement and the preliminary measurement results achieved in order to eliminate potential damages to both pump and mechanical seal.

Parametric Effects of Debris Source, Environments, and Design Options on the Overall Performance of ECCS Recirculation Sump

International Nuclear Information System (INIS)

Park, Jong Woon; Kim, Chang Hyun

2006-01-01

A primary safety issue regarding long-term recirculation core cooling following a LOCA (Loss of Coolant Accident) is that LOCA-generated debris may be transported to the recirculation sump screen, resulting in adverse blockage on the sump screen and deterioration of available NPSH (Net Positive Suction Head) of ECCS (Emergency Core Cooling System). USNRC identified this as Generic Safety Issue (GSI) 191 and issued the Generic Letter 04-02 to resolve the issue. The GL required that all PWR owners perform an engineering assessment of their containment recirculation sumps to ensure they will not suffer from excessive blockage. The guidance report (GR) for PWR sump performance evaluation has been developed by NEI (Nuclear Energy Institute) and approved by the USNRC. In Korea, Korea Hydro and Nuclear Power Company (KHNP) is performing the assessment of Kori unit 1 and planning for remaining plants in the near future. The objective of the assessment is to derive required plant modifications including insulation, sump screen, etc. To derive the cost-effective modification items, we have to get insight on the parametric effects of plant conditions and design. Therefore, the general effects of debris source, containment environments and debris interceptor on the performance of ECCS recirculation sump with respect to head loss are parametrically investigated

Developments in accelerators for heavy ion fusion

International Nuclear Information System (INIS)

Keefe, D.

1985-01-01

The long term goal of Heavy Ion Fusion (HIF) is the development of an accelerator with the large beam power, large beam stored-energy, and high brightness needed to implode small deuterium-tritium capsules for fusion power. While studies of an RF linac/storage ring combination as an intertial fusion driver continue in Japan and Europe, the US program in recent times has concentrated on the study of the suitability of linear induction acceleration of ions for this purpose. Novel features required include use of multiple beams, beam current amplification in the linac, and manipulation of long beam bunches with a large velocity difference between head and tail. Recent experiments with an intense bright beam of cesium ions have established that much higher currents can be transported in a long quadrupole system than was believed possible a few years ago. A proof-of-principle ion induction linac to demonstrate beam current amplification with multiple beams is at present being fabricated at LBL

Developments in accelerators for heavy ion fusion

International Nuclear Information System (INIS)

Keefe, D.

1985-05-01

The long term goal of Heavy Ion Fusion (HIF) is the development of an accelerator with the large beam power, large beam stored-energy, and high brightness needed to implode small deuterium-tritium capsules for fusion power. While studies of an rf linac/storage ring combination as an inertial fusion driver continue in Japan and Europe, the US program in recent times has concentrated on the study of the suitability of linear induction acceleration of ions for this purpose. Novel features required include use of multiple beams, beam current amplification in the linac, and manipulation of long beam bunches with a large velocity difference between head and tail. Recent experiments with an intense bright beam of cesium ions have established that much higher currents can be transported in a long quadrupole system than was believed possible a few years ago. A proof-of-principle ion induction linac to demonstrate beam current amplification with multiple beams is at present being fabricated at LBL. 28 refs., 4 figs

Modeling and optimization of integrated exhaust gas recirculation and multi-stage waste heat recovery in marine engines

DEFF Research Database (Denmark)

Kyriakidis, Fotis; Sørensen, Kim; Singh, Shobhana

2017-01-01

Waste heat recovery combined with exhaust gas recirculation is a promising technology that can address both the issue of NOx (nitrogen oxides) reduction and fuel savings by including a pressurized boiler. In the present study, a theoretical optimization of the performance of two different...... configurations of steam Rankine cycles, with integrated exhaust gas recirculation for a marine diesel engine, is presented. The first configuration employs two pressure levels and the second is configured with three-pressure levels. The models are developed in MATLAB based on the typical data of a large two......-stroke marine diesel engine. A turbocharger model together with a blower, a pre-scrubber and a cooler for the exhaust gas recirculation line, are included. The steam turbine, depending on the configuration, is modeled as either a dual or triple pressure level turbine. The condensation and pre-heating process...

Saponification pretreatment and solids recirculation as a new anaerobic process for the treatment of slaughterhouse waste.

Science.gov (United States)

Affes, R; Palatsi, J; Flotats, X; Carrère, H; Steyer, J P; Battimelli, A

2013-03-01

Different configurations of anaerobic process, adapted to the treatment of solid slaughterhouse fatty waste, were proposed and evaluated in this study. The tested configurations are based on the combination of anaerobic digestion with/without waste saponification pretreatment (70 °C during 60 min) and with/without recirculation of the digestate solid fraction (ratio=20% w/w). After an acclimation period of substrate pulses-feeding cycles, the reactors were operated in a semi-continuous feeding mode, increasing organic loading rates along experimental time. The degradation of the raw substrate was shown to be the bottleneck of the whole process, obtaining the best performance and process yields in the reactor equipped with waste pretreatment and solids recirculation. Saponification promoted the emulsification and bioavailability of solid fatty residues, while recirculation of solids minimized the substrate/biomass wash-out and induced microbial adaptation to the treatment of fatty substrates. Copyright © 2013 Elsevier Ltd. All rights reserved.

ETA-II accelerator upgrades

International Nuclear Information System (INIS)

Nilson, D.G.; Deadrick, F.J.; Hibbs, S.M.; Sampayan, S.E.; Petersen, D.E.

1991-09-01

We discuss recent improvements to the ETA-II linear induction electron accelerator. The accelerator's cells have been carefully reconditioned to raise the maximum accelerating gap voltage from approximately 100 kV to 125 kV. Insulators of Rexolite plastic in a new ''zero-gap'' arrangement replaced the alumina originals after several alternative materials were investigated. A new multi-cable current feed system will be used to eliminate pulse reflection interactions encountered in earlier experiments. Improved alignment fixtures have been installed to help minimize beam perturbation due to poorly aligned intercell magnets between 10-cell groups. A stretched wire alignment technique (SWAT) has been utilized to enhance overall magnetic alignment, and to characterize irreducible alignment errors. These changes are in conjunction with an expansion of the accelerator from a 20-cell to a 60-cell configuration. When completed, the upgraded accelerator is expected to deliver 2.5 kA of electron beam current at 7.5 MeV in bursts of up to fifty 70-ns pulses at a 5-kHz repetition rate. A 5.5-meter-long wiggler will convert the energy into 3-GW microwave pulses at 140 GHz for plasma heating experiments in the Microwave Tokamak Experiment (MTX)

Two-beam accelerator

International Nuclear Information System (INIS)

Sessler, A.M.; Hopkins, D.B.

1986-06-01

The Two-Beam Accelerator (TBA) consists of a long high-gradient accelerator structure (HGS) adjacent to an equal-length Free Electron Laser (FEL). In the FEL, a beam propagates through a long series of undulators. At regular intervals, waveguides couple microwave power out of the FEL into the HGS. To replenish energy given up by the FEL beam to the microwave field, induction accelerator units are placed periodically along the length of the FEL. In this manner it is expected to achieve gradients of more than 250 MV/m and thus have a serious option for a 1 TeV x 1 TeV linear collider. The state of present theoretical understanding of the TBA is presented with particular emphasis upon operation of the ''steady-state'' FEL, phase and amplitude control of the rf wave, and suppression of sideband instabilities. Experimental work has focused upon the development of a suitable HGS and the testing of this structure using the Electron Laser Facility (ELF). Description is given of a first test at ELF with a seven-cell 2π/3 mode structure which without preconditioning and with a not-very-good vacuum nevertheless at 35 GHz yielded an average accelerating gradient of 180 MV/m

Maintenance of reactor recirculation pumps [Paper No.: II-1

International Nuclear Information System (INIS)

Ansari, M.A.; Bhat, K.P.

1981-01-01

At Tarapur Atomic Power Station (TAPS), two reactor recirculation pumps are provided, one each for the two reactor units. The performance of pumps has been uniformly good; however, leakage through the cartridge type, two stage, mechanical seals which are installed on these pumps was encountered on few occasions. The paper describes the leakage problems, identification of certain design deficiencies and rectification carried out at TAPS for overcoming these problems. (author)

Experimental on fly ash recirculation with bottom feeding to improve the performance of a circulating fluidized bed boiler co-burning coal sludge

Energy Technology Data Exchange (ETDEWEB)

Duan, Lunbo; Xu, Guiling; Liu, Daoyin; Chen, Xiaoping; Zhao, Changsui [Southeast Univ., Nanjing (China). School of Energy and Environment

2013-07-01

With the aim of reducing carbon content in fly ash, fly ash recirculation with bottom feeding (FARBF) technology was applied to a 75 t/h Circulating Fluidized Bed (CFB) boiler burning mixture of coal and coal sludge. And industrial experiments were carried out to investigate the influence of FARBF technology on the combustion performance and pollutant emission characteristics of the CFB boiler. Results show that as the recirculation rate of fly ash increases, the CFB dense bed temperature decreases while the furnace outlet temperature increases, and the temperature distribution in the furnace becomes uniform. Compared with the conditions without fly ash recirculation, the combustion efficiency increases from 92 to 95% when the recirculation rate increases to 8 t/h, and the desulfurization efficiency also increases significantly. As the recirculation rate increases, the emissions of NO and CO decrease, but the particulate emission increases. The present study indicates that FARBF technology can improve the combustion performance and desulfurization efficiency for the CFB boilers burning coal sludge, and this can bring large economical and environmental benefits in China.

Design of two-column batch-to-batch recirculation to enhance performance in ion-exchange chromatography.

Science.gov (United States)

Persson, Oliver; Andersson, Niklas; Nilsson, Bernt

2018-01-05

Preparative liquid chromatography is a separation technique widely used in the manufacturing of fine chemicals and pharmaceuticals. A major drawback of traditional single-column batch chromatography step is the trade-off between product purity and process performance. Recirculation of impure product can be utilized to make the trade-off more favorable. The aim of the present study was to investigate the usage of a two-column batch-to-batch recirculation process step to increase the performance compared to single-column batch chromatography at a high purity requirement. The separation of a ternary protein mixture on ion-exchange chromatography columns was used to evaluate the proposed process. The investigation used modelling and simulation of the process step, experimental validation and optimization of the simulated process. In the presented case the yield increases from 45.4% to 93.6% and the productivity increases 3.4 times compared to the performance of a batch run for a nominal case. A rapid concentration build-up product can be seen during the first cycles, before the process reaches a cyclic steady-state with reoccurring concentration profiles. The optimization of the simulation model predicts that the recirculated salt can be used as a flying start of the elution, which would enhance the process performance. The proposed process is more complex than a batch process, but may improve the separation performance, especially while operating at cyclic steady-state. The recirculation of impure fractions reduces the product losses and ensures separation of product to a high degree of purity. Copyright © 2017 Elsevier B.V. All rights reserved.

Monitoring of Leachate Recirculation in a Bioreactor Using Electrical Resistivity

Science.gov (United States)

Grellier, S.; Bureau, N.; Robain, H.; Tabbagh, A.; Camerlynck, C.; Guerin, R.

2004-05-01

The bioreactor is a concept of waste landfill management consisting in speeding up the biodegradation by optimizing the moisture content through leachate recirculation. Electrical resistivity tomography (ERT) is carried out with fast resistivity-meter (Syscal Pro, IRIS Instruments, developed in the framework of the research project CERBERE 01V0665-69, funded by the French Research Ministry) to monitor leachate recirculation. During a recirculation period waste moisture increases, so that electrical resistivity may decrease, but at the same time temperature and mineralization of both waste and leachate become intermixed. If waste temperature is much higher than leachate temperature electrical resistivity will not decrease as much as if the temperature difference was smaller. If leachate mineralization (i.e. leachate conductivity) is higher than that of wet waste in the landfill, electrical resistivity will tend to decrease. Otherwise for example after an addition of rain water into the leachate storage or in case of very wet waste, the resistivities of each medium (leachate and wet waste) can be almost the same, so that leachate mineralization will not have a great influence on waste resistivity. Resistivity measurements were performed during 85 minutes injection trials (with a discharge of 20 m3 h-1) where leachate was injected through a vertical borehole perforated between 1.85 and 4.15 m. Three first measurements are made during the injection (3, 30 and 60 minutes from the beginning of the injection) and the two other after the injection period (8 and 72 minutes after the end of the injection). Apparent and interpreted resistivity variations that occurred during injection trials, expressed as the relative differences (in %) between apparent, respectively interpreted, resistivity during injection and apparent, respectively interpreted, resistivity before injection (reference measurement) show the formation of a plume (a negative anomaly: resistivity decreases with

λ-prophage induction in E.coli cells by radiation with different LET

International Nuclear Information System (INIS)

Bonev, M.N.; Collev, S.D.

1997-01-01

λ-prophage induction in E.coli H fr H (λ) strain after irradiation with α-particles, accelerated helium ions, boron and carbon ions, as well as deuterons is investigated. The dose dependence of the fraction of induced cells is measured and its initial slope (λ-induction potency - λ i p) is determined. It is shown that the dependence of λ i p on LET is a curve with a maximum

The impact of recirculation, ventilation and filters on secondary organic aerosols generated by indoor chemistry

DEFF Research Database (Denmark)

Fadeyi, M.O.; Weschler, Charles J.; Tham, K.W.

2009-01-01

This study examined the impact of recirculation rates (7 and 14 h(-1)), ventilation rates (1 and 2 h(-1)), and filtration on secondary organic aerosols (SOAs) generated by ozone of outdoor origin reacting with limonene of indoor origin. Experiments were conducted within a recirculating air handling......, but this was more than offset by the increased dilution of SOA derived from ozone-initiated chemistry. The presence of a particle filter (new or used) strikingly lowered SOA number and mass concentrations compared with conditions when no filter was present. Even though the particle filter in this study had only 35...

Water cortisol and testosterone in Nile tilapia (Oreochromis niloticus) recirculating aquaculture systems

NARCIS (Netherlands)

Mota, Vasco C.; Martins, Catarina I.M.; Eding, Ep H.; Canário, Adelino V.M.; Verreth, Johan A.J.

2017-01-01

The accumulation of steroids released by fish in recirculating aquaculture systems (RAS) may potentially influence their physiology and behavior. The present study examined the release rate of cortisol and testosterone by Nile tilapia, Oreochromis niloticus, and their accumulation in six identical

The potential use of constructed wetlands in a recirculating aquaculture system for shrimp culture

International Nuclear Information System (INIS)

Lin, Y.-F.; Jing, S.-R.; Lee, D.-Y.

2003-01-01

Constructed wetlands improved water qualities and consequently increased the shrimp growth and survival in a recirculating system. - A pilot-scale constructed wetland unit, consisting of free water surface (FWS) and subsurface flow (SF) constructed wetlands arranged in series, was integrated into an outdoor recirculating aquaculture system (RAS) for culturing Pacific white shrimp (Litopenaeus vannamei). This study evaluated the performance of the wetland unit in treating the recirculating wastewater and examined the effect of improvement in water quality of the culture tank on the growth and survival of shrimp postlarvae. During an 80-day culture period, the wetland unit operated at a mean hydraulic loading rate of 0.3 m/day and effectively reduced the influent concentrations of 5-day biochemical oxygen demand (BOD 5 , 24%), suspended solids (SS, 71%), chlorophyll a (chl-a, 88%), total ammonium (TAN, 57%), nitrite nitrogen (NO 2 -N, 90%) and nitrate nitrogen (NO 3 -N, 68%). Phosphate (PO 4 -P) reduction was the least efficient (5.4%). The concentrations of SS, Chl-a, turbidity and NO 3 -N in the culture tank water in RAS were significantly (P≤0.05) lower than those in a control aquaculture system (CAS) that simulated static pond culture without wetland treatment. However, no significant difference (P≤0.05) in BOD 5 , TAN and NO 2 -N was found between the two systems. At the end of the study, the harvest results showed that shrimp weight and survival rate in the RAS (3.8±1.8 g/shrimp and 90%) significantly (P≤0.01) exceeded those in the CAS (2.3±1.5 g/shrimp and 71%). This study concludes that constructed wetlands can improve the water quality and provide a good culture environment, consequently increasing the shrimp growth and survival without water exchange, in a recirculating system

The potential use of constructed wetlands in a recirculating aquaculture system for shrimp culture

Energy Technology Data Exchange (ETDEWEB)

Lin, Y.-F.; Jing, S.-R.; Lee, D.-Y

2003-05-01

Constructed wetlands improved water qualities and consequently increased the shrimp growth and survival in a recirculating system. - A pilot-scale constructed wetland unit, consisting of free water surface (FWS) and subsurface flow (SF) constructed wetlands arranged in series, was integrated into an outdoor recirculating aquaculture system (RAS) for culturing Pacific white shrimp (Litopenaeus vannamei). This study evaluated the performance of the wetland unit in treating the recirculating wastewater and examined the effect of improvement in water quality of the culture tank on the growth and survival of shrimp postlarvae. During an 80-day culture period, the wetland unit operated at a mean hydraulic loading rate of 0.3 m/day and effectively reduced the influent concentrations of 5-day biochemical oxygen demand (BOD{sub 5}, 24%), suspended solids (SS, 71%), chlorophyll a (chl-a, 88%), total ammonium (TAN, 57%), nitrite nitrogen (NO{sub 2}-N, 90%) and nitrate nitrogen (NO{sub 3}-N, 68%). Phosphate (PO{sub 4}-P) reduction was the least efficient (5.4%). The concentrations of SS, Chl-a, turbidity and NO{sub 3}-N in the culture tank water in RAS were significantly (P{<=}0.05) lower than those in a control aquaculture system (CAS) that simulated static pond culture without wetland treatment. However, no significant difference (P{<=}0.05) in BOD{sub 5}, TAN and NO{sub 2}-N was found between the two systems. At the end of the study, the harvest results showed that shrimp weight and survival rate in the RAS (3.8{+-}1.8 g/shrimp and 90%) significantly (P{<=}0.01) exceeded those in the CAS (2.3{+-}1.5 g/shrimp and 71%). This study concludes that constructed wetlands can improve the water quality and provide a good culture environment, consequently increasing the shrimp growth and survival without water exchange, in a recirculating system.

Heavy-ion fusion accelerator research, 1985

International Nuclear Information System (INIS)

1986-10-01

A plan for exploring the physics and technology of induction linac development is discussed which involves a series of increasingly sophisticated experiments. The first is the single-beam transport experiment, which has explored the physics of a single space-charge-dominated beam. Second is the multiple-beam experiment in which four independent beams will be transported and accelerated through a multigap accelerating structure. The single-beam transport experiment is described, and some results are given of stability studies and instrumentation studies. The design and fabrication of the multi-beam experiment are described, as well as results of a first round of experiments in which beam-current amplification was observed. Concurrent theoretical work, resulting in a variety of acce-leration schedules and sets of associated voltage waveforms required to implement the experiments, is also reported

Nutrient Management in Recirculating Hydroponic Culture

Science.gov (United States)

Bugbee, Bruce

2004-01-01

There is an increasing need to recirculate and reuse nutrient solutions in order to reduce environmental and economic costs. However, one of the weakest points in hydroponics is the lack of information on managing the nutrient solution. Many growers and research scientists dump out nutrient solutions and refill at weekly intervals. Other authors have recommended measuring the concentrations of individual nutrients in solution as a key to nutrient control and maintenance. Dumping and replacing solution is unnecessary. Monitoring ions in solution is not always necessary; in fact the rapid depletion of some nutrients often causes people to add toxic amounts of nutrients to the solution. Monitoring ions in solution is interesting, but it is not the key to effective maintenance.

Accelerator and Fusion Research Division. Annual report, October 1978-September 1979

International Nuclear Information System (INIS)

1980-03-01

Topics covered include: Super HILAC and Bevalac operations; high intensity uranium beams line item; advanced high charge state ion source; 184-inch synchrocyclotron; VENUS project; positron-electron project; high field superconducting accelerator magnets; beam cooling; accelerator theory; induction linac drivers; RF linacs and storage rings; theory; neutral beam systems development; experimental atomic physics; neutral beam plasma research; plasma theory; and the Tormac project

Adoption of Recirculating Aquaculture Systems in Large Pangasius Farms: A Choice Experiment

NARCIS (Netherlands)

Pham, T.A.N.; Gielen-Meuwissen, M.P.M.; Le, T.C.; Verreth, J.A.J.; Bosma, R.H.; Oude Lansink, A.G.J.M.

2016-01-01

A growing number of European customers’ demands certified pangasius such as ASC in order to ensure sustainable production. Implementing Recirculating Aquaculture Systems (RAS) contributes to an improved water quality, a key issue in achieving ASC certification. This study uses a choice experiment to

Removal of nitrogen by Algal Turf Scrubber Technology in recirculating aquaculture system

NARCIS (Netherlands)

Valeta, J.; Verdegem, M.C.J.

2015-01-01

Ongoing research in recirculation aquaculture focuses on evaluating and improving the purification potential of different types of filters. Algal Turf Scrubber (ATS) are special as they combine sedimentation and biofiltration. An ATS was subjected to high nutrient loads of catfish effluent to

Overview of The Pulse Line Ion Accelerator

International Nuclear Information System (INIS)

Briggs, R.J.; Bieniosek, F.M.; Coleman, J.E.; Eylon, S.; Henestroza, E.; Leitner, M.; Logan, B.G.; Reginato, L.L.; Roy, P.K.; Seidl, P.A.; Waldron, W.L.; Yu, S.S.; Barnard, J.J.; Caporaso, G.J.; Friedman, A.; Grote, D.P.; Nelson, S.D.

2006-01-01

An overview of the Pulse Line Ion Accelerator (PLIA) concept and its development is presented. In the PLIA concept a pulse power driver applied to one end of a helical pulse line creates a traveling wave pulse that accelerates and axially confines a heavy ion beam pulse The motivation for its development at the IFE-VNL is the acceleration of intense, short pulse, heavy ion beams to regimes of interest for studies of High Energy Density Physics and Warm Dense Matter. Acceleration scenarios with constant parameter helical lines are described which result in output energies of a single stage much larger than the several hundred kilovolt peak voltages on the line, with a goal of 3-5 MeV/meter acceleration gradients. The main attraction of the concept is the very low cost it promises. It might be described crudely as an ''air core'' induction linac where the pulse-forming network is integrated into the beam line so the accelerating voltage pulse can move along with the ions to get voltage multiplication

Corrosion products, activity transport and deposition in boiling water reactor recirculation systems

International Nuclear Information System (INIS)

Alder, H.P.; Buckley, D.; Grauer, R.; Wiedemann, K.H.

1992-01-01

The deposition of activated corrosion products in the recirculation loops of Boiling Water Reactors produces increased radiation levels which lead to a corresponding increase in personnel radiation dose during shut down and maintenance. The major part of this dose rate is due to cobalt-60. Based on a comprehensive literature study concerning this theme, it has been attempted to identify the individual stages of the activity build-up and to classify their importance. The following areas are discussed in detail: The origins of the corrosion products and of cobalt-59 in the reactor feedwaters; the consolidation of the cobalt in the fuel pins deposits (activation); the release and transport of cobalt-60; the build-up of cobalt-60 in the corrosion products in the recirculation loops. Existing models of the build-up of circuit radioactivity are discussed and the operating experiences from selected reactors are summarized. 90 refs, figs and tabs

Study of performances, stability and microbial characterization of a Sequencing Batch Biofilter Granular Reactor working at low recirculation flow.

Science.gov (United States)

De Sanctis, Marco; Beccari, Mario; Di Iaconi, Claudio; Majone, Mauro; Rossetti, Simona; Tandoi, Valter

2013-02-01

The Sequencing Batch Biofilter Granular Reactor (SBBGR) is a promising wastewater treatment technology characterized by high biomass concentration in the system, good depuration performance and low sludge production. Its main drawback is the high energy consumption required for wastewater recirculation through the reactor bed to ensure both shear stress and oxygen supply. Therefore, the effect of low recirculation flow on the long-term (38 months) performance of a laboratory scale SBBGR was studied. Both the microbial components of the granules, and their main metabolic activities were evaluated (heterotrophic oxidation, nitrification, denitrification, fermentation, sulphate reduction and methanogenesis). The results indicate that despite reduced recirculation, the SBBGR system maintained many of its advantageous characteristics. Copyright © 2012 Elsevier Ltd. All rights reserved.

An analysis of the thermodynamic efficiency for exhaust gas recirculation-condensed water recirculation-waste heat recovery condensing boilers (EGR-CWR-WHR CB)

International Nuclear Information System (INIS)

Lee, Chang-Eon; Yu, Byeonghun; Lee, Seungro

2015-01-01

This study presents fundamental research on the development of a new boiler that is expected to have a higher efficiency and lower emissions than existing boilers. The thermodynamic efficiency of exhaust gas recirculation-condensed water recirculation-waste heat recovery condensing boilers (EGR-CWR-WHR CB) was calculated using thermodynamic analysis and was compared with other boilers. The results show the possibility of obtaining a high efficiency when the temperature of the exhaust gas is controlled within 50–60 °C because water in the exhaust gas is condensed within this temperature range. In addition, the enthalpy emitted by the exhaust gas for the new boiler is smaller because the amount of condensed water is increased by the high dew-point temperature and the low exhaust gas temperature. Thus, the new boiler can obtain a higher efficiency than can older boilers. The efficiency of the EGR-CWR-WHR CB proposed in this study is 93.91%, which is 7.04% higher than that of existing CB that is currently used frequently. - Highlights: • The study presents the development of a new boiler expected to have a high efficiency. • Thermodynamic efficiency of EGR-CWR-WHR condensing boiler was calculated. • Efficiency of EGR-CWR-WHR CB is 93.91%, which is 7.04% higher than existing CB

Longitudinal transport measurements in an energy recovery accelerator with triple bend achromat arcs

Directory of Open Access Journals (Sweden)

F. Jackson

2016-12-01

Full Text Available Longitudinal properties of electron bunches (energy spread and bunch length and their manipulation are of importance in free electron lasers (FELs, where magnetic bunch length compression is a common feature of beam transport. Recirculating accelerators and energy recovery linac accelerators (ERLs have been used as FEL drivers for several decades and control of longitudinal beam transport is particularly important in their magnet lattices. We report on measurements of longitudinal transport properties in an ERL-FEL, the ALICE (Accelerators and Lasers in Combined Experiments accelerator at Daresbury Laboratory. ALICE is an energy recovery research accelerator that drives an infrared free electron laser. By measuring the time of arrival of electron bunches, the canonical longitudinal transport quantities were measured in the beam transport and bunch compression sections of the lattice. ALICE includes a four-dipole bunch compression chicane providing fixed longitudinal transport, and triple bend achromat arcs including sextupole magnets where the first and second order longitudinal transport can be adjusted. The longitudinal transport properties in these lattice sections were measured and compared with the theoretical model of the lattice. A reasonable level of agreement has been found. The effect of sextupoles in second order, as well as first order, longitudinal correction is considered, with the measurements indicating the level of alignment of the beam to the center of the sextupole.

CONVECTIVE HEAT TRANSFER IN CYCLONE DEVICE WITH EXTERNAL GAS RECIRCULATION

Directory of Open Access Journals (Sweden)

S. V. Karpov

2016-01-01

Full Text Available The article considers the convective heat transfer on the surface of a hollow cylinder or several billets in a cyclone device with the new principle of external gas recirculation. According to this principle, transport of coolant from the lateral surface of the chamber, where the temperature is the highest, in the axial region is being fulfilled due to the pressure drop between the wall and axial areas of cyclonic flow. Dependency analysis of average and local heat transfer coefficients from operational and geometrical parameters has been performed; the generalized similarity equations for the calculation of the latter have been suggested. It is demonstrated that in case of download of a cyclone chamber with several billets, the use of the considered scheme of the external recirculation due to the specific characteristics of aerodynamics practically does not lead to noticeable changes in the intensity of convective heat transfer. Both experimental data and the numerical simulation results obtained with the use of OpenFOAM platform were used in the work. The investigations fulfilled will expand the area of the use of cyclone heating devices.

NLC Hybrid Solid State Induction Modulator

CERN Document Server

Cassel, R L; Pappas, G C; Delamare, J E

2004-01-01

The Next Linear Collider accelerator proposal at SLAC requires a high efficiency, highly reliable, and low cost pulsed power modulator to drive the X-band klystrons. The original NLC envisions a solid state induction modulator design to drive up to 8 klystrons to 500 kV for 3 μs at 120 PPS with one modulator delivering greater than 1,000 MW pulse, at 500 kW average. A change in RF compression techniques resulted in only two klystrons needed pulsing per modulator at a reduced pulse width of 1.6 μsec or approximately 250 MW of the pulsed power and 80 kW of average powers. A prototype Design for Manufacturability (DFM) 8-pack modulator was under construction at the time of the change, so a redirection of modulator design was in order. To utilities the equipment which had already be fabricated, a hybrid modulator was designed and constructed using the DFM induction modulator parts and a conventional pulse transformer. The construction and performance of this hybrid two klystron Induction modul...

Acceleration of Vaporization, Atomization, and Ionization Efficiencies in Inductively Coupled Plasma by Merging Laser-Ablated Particles with Hydrochloric Acid Gas.

Science.gov (United States)

Nakazawa, Takashi; Izumo, Saori; Furuta, Naoki

2016-01-01

To accelerate the vaporization, atomization, and ionization efficiencies in laser ablation inductively coupled plasma mass spectrometry, we merged HCl gas with laser-ablated particles before introduction into the plasma, to convert their surface constituents from oxides to lower-melting chlorides. When particles were merged with HCl gas generated from a HCl solution at 200°C, the measured concentrations of elements in the particles were 135% higher on average than the concentrations in particles merged with ultrapure water vapor. Particle corrosion and surface roughness were observed by scanning electron microscopy, and oxide conversion to chlorides was confirmed by X-ray photoelectron spectroscopy. Under the optimum conditions, the recoveries of measured elements improved by 23% on average, and the recoveries of elements with high-melting oxides (Sr, Zr, and Th) improved by as much as 36%. These results indicate that vaporization, atomization, and ionization in the ICP improved when HCl gas was merged with the ablated particles.

Emittance variations in current-amplifying ion induction linacs

International Nuclear Information System (INIS)

Fessenden, T.J.

1991-01-01

Since 1985 the Heavy Ion Fusion Accelerator Research program at the Lawrence Berkeley Laboratory has been studying current amplification and emittance variations in MBE-4, a four-cesium-beam induction linac. This experiment models much of the accelerator physics of the electrostatically focused section of a fusion driver. Four space-charge dominated Cs + beams, initially about one meter in length at currents of 5-10 mA, are focused by electrostatic quadrupoles and accelerated in parallel from approximately 200 keV up to one MeV by 24 accelerating gaps. Final currents of 20-40 mA per beam are typical. Recent experiments with extremely low emittance beams (var-epsilon n =0.03 mm-mRad) have investigated variations of transverse and longitudinal normalized emittance for drifting and accelerating beams. These very strongly tune-depressed beams (σ 0 =72 degree, σ∼6 degree) are difficult to match to the accelerator so as to avoid emittance growth during acceleration. During transport strong emittance fluctuations are observed in good qualitative agreement with simulations. Warmer beams with less tune depression exhibit little to no emittance growth, show smaller emittance fluctuations, and are much easier to match. A summary of findings from the MBE-4 studies is presented

Emittance variations in current-amplifying ion induction linacs

International Nuclear Information System (INIS)

Fessenden, T.J.

1991-04-01

Since 1985 the Heavy Ion Fusion Accelerator Research program at the Lawrence Berkeley Laboratory has been studying current amplification and emittance variations in MBE-4, a four-cesium-beam induction linac. This experiment models much of the accelerator physics of the electrostatically focused section of a fusion driver. Four space-charge dominated Cs + beams, initially about one meter in length at currents of 5--10 mA, are focused by electrostatic quadrupoles and accelerated in parallel from approximately 200 keV up to one MeV by 24 accelerating gaps. Final currents of 20--40 mA per beam are typical. Recent experiments with extremely low emittance beams (ε n = 0.03 mm-mRad) have investigated variations of transverse and longitudinal normalized emittance for drifting and accelerating beams. These very strongly tune-depressed beams (σ o = 72 degrees, σ∼6 degree) are difficult to match the accelerator so as to avoid emittance growth during acceleration. During transport strong emittance fluctuations are observed in good qualitative agreement with simulations. Warmer beams with less tune depression exhibit little to no emittance growth, show smaller emittance fluctuations, and are much easier to match. A summary of findings from the MBE-4 studies is presented. 12 refs., 8 figs