Energy Technology Data Exchange (ETDEWEB)

The Linac Coherent Light Source (LCLS) will be the world's first x-ray free-electron laser (FEL). To ensure the vitality of FEL lasing, it is critical to preserve the high quality of the electron beam during acceleration and compression. The peak current and final energy are very sensitive to system jitter. To minimize this sensitivity, a longitudinal feedback system on the bunch length and energy is required, together with other diagnostics and feedback systems (e.g., on transverse phase space). Here, we describe a simulation framework, which includes a realistic jitter model for the LCLS accelerator system, the RF acceleration, structure wakefield, and second order optics. Simulation results show that to meet the tight requirements set by the FEL, such a longitudinal feedback system is mandatory.

International Nuclear Information System (INIS)

FELs require tight control of the amplitudes and phase of the fields in two linear accelerator tanks to obtain stable lasing. The accelerator control loops must establish constant, stable, repeatable amplitudes and phases of the rf fields and must have excellent bandwidth to control high-frequency noise components. A model of the feedback loops has been developed that agrees well with measurements and allows easy substitution of components and circuits, thus reducing breadboarding requirements. The model permits both frequency and time-domain analysis. The accelerator control scheme and model are described and the control of noise in feedback loops is discussed, showing how low-frequency-noise components (errors) can be corrected, but high-frequency-noise components (errors) are actually amplified by the feedback circuit. Measurements of noise in both open- and ...

International Nuclear Information System (INIS)

The Los Alamos FEL requires tight control of the amplitudes and phases of the fields in two linear accelerator tanks to obtain stable lasing. The accelerator control loops must establish constant, stable, repeatable amplitudes and phases of the rf fields and must have excellent bandwidth to control high-frequency noise components. A model of the feedback loops has been developed that agrees well with measurements and allows easy substitution of components and circuits, thus reducing breadboarding requirements. The model permits both frequency and time-domain analysis. This paper describes the accelerator control scheme and our model and discusses the control of noise in feedback loops, showing how low-frequency-noise components (errors) can be corrected, but high-frequency-noise components (errors) are actually amplified by the feedback circuit. Measurements of ...

Science.gov (United States)

A dc-to-dc converter has been designed which employs the synchronizing phenomenon in the transistor core multivibrator. In the proposed circuit, the voltage feedback is applied from the control transistor and the current feedback is applied from the main transistor. The operation of the converter is analyzed by the averaging method of the state space technique. The converter features small switching loss and is suitable for high frequency operation. An efficiency of more than 95% is obtained for 5 V, 3 A output at a switching frequency of 200 kHz.

British Library Electronic Table of Contents (United Kingdom)

Abstract Recent work (Schawinski et al.) indicates that star-forming early-type galaxies residing in the blue cloud migrate rapidly to the red sequence within around a Gyr, passing through several phases of increasingly strong active galactic nucleus (AGN) activity in the process. We show that natural depletion of the cold gas reservoir through star formation (i.e. in the absence of any feedback from the AGN) induces a blue-to-red reddening rate that is several factors lower than that observed by Schawinski et al. This is because the gas depletion rate due to star formation alone is too slow, implying that another process needs to be invoked to remove cold gas from the system and accelerate the reddening rate. We develop a simple phenomenological model, in which a fraction of the AGN-s lum...

International Nuclear Information System (INIS)

The term Smith-Purcell free electron laser can be employed generally to describe any coherent radiation source in which a diffraction grating is used to couple an electron beam with the electromagnetic field. To date, most practical developments of this concept have focused on devices which operate in the millimeter spectral regime. In this paper construction of a Smith-Purcell free-electron laser operating in the far-infrared (FIR) region using a novel resonator cavity design and the electron beam from a low energy (0.5-5 MeV) radio-frequency accelerator will be discussed. A tunable source in this region would have many applications and since the beam energy is low, the small size and low overall cost of such a device would make it a laboratory instrument. Current projects which are progressing towards developing a FIR source are the programs at Stanford and CREOL. Both of these projects are using permanent magnet ...

International Nuclear Information System (INIS)

Initial design parameters and early operational results of a 50 MeV high brightness electron linear accelerator are described. The system utilizes a radio frequency electron gun operating at a frequency of 2.856 GHz and a nominal output energy of 4.5 MeV followed by two, 2#pi#/3 mode, disc loaded, traveling wave accelerating sections. The gun cathode is photo excited with short (6 psec) laser pulses giving design peak currents of a few hundred amperes. The system will be utilized to carry out infra-red FEL studies and investigation of new high gradient accelerating structures.

Energy Technology Data Exchange (ETDEWEB)

A self-seeded free electron laser (FEL) provides a high gain and extraction efficiency for the emitted light. An accelerator outputs a beam of electron pulses to a permanent magnet wiggler having an input end for receiving the electron pulses and an output end for outputting light and the electron pulses. An optical feedback loop collects low power light in a small signal gain regime at the output end of said wiggler and returns the low power light to the input end of the wiggler while outputting high power light in a high signal gain regime.

International Nuclear Information System (INIS)

Daya Bay Nuclear Power Station has made a series of tries and efforts on radiation source control and benefited from them since it was put into commercial operation. Some of them were introduced from experience feedbacks of foreign nuclear power industry and others came from our own good practices

Science.gov (United States)

Current medical visualization technology intended for positional guidance in surgical applications may only ever have limited utility in the operating room due to the preexisting visual requirements of surgical practice. Additionally, visual systems impose limits as a result of their high latency, poor image resolution, problems with stereopsis and physical strain upon the user. Audio technology is relatively unexamined in the broad range of available methodologies for medical devices. The potential to translate surgical instrument position into audio feedback presents a novel solution to the human factors and engineering problems faced by visual display technology because audio technology employs a rich and as yet unburdened sensory modality. We describe an experimental system we have developed for investigating this new interface design approach using commercially available hardware. PMID:10173065

Science.gov (United States)

Heart Arrest

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

International Nuclear Information System (INIS)

For the recruitment, training and position qualification of the simulator instructors and feedback of training effect, the management approaches are formulated in 'The System for Simulator Training and Licensing Examination of Daya Bay Nuclear Power Station Operators'. The concrete requirements on the professional knowledge, work experience and foreign language ability of a simulator instructor are put forward. The process of instructor training is designed. The training items include the trainer training, pedagogy training, time management training, operation activities training during outage of unit, 'shadow' training and on-the-jot training on simulator courses. Job rotation is realized between simulator instructor and licensing personnel on site. New simulator instructor must pass the qualification identification. After a duration of 2 years, re-qualification has to be carried out. On the basis of the ...

Energy Technology Data Exchange (ETDEWEB)

The two model MP Tandem Van de Graaff accelerators at Brookhaven have been used in a four-stage accel-decel configuration to produce highly stripped low energy heavy ions. The performance in this mode of operation has now been substantially improved by modifications of the second accelerator. The inclined field acceleration tube electrodes at the exit of this accelerator were replaced by straight electrodes, the vacuum was improved and the maximum negative terminal potential was increased. Higher intensity beams of heavier highly stripped ions can now be produced at lower energies than before.

Energy Technology Data Exchange (ETDEWEB)

(B204)Probabilistic risk assessment (PRA) insights are now used by the United States Nuclear Regulatory Commission (USNRC) to confirm the level of safety for plant operations and to justify changes in nuclear power plant operating requirements, both on an exception basis and as changeds to a plant's licensing basis. This report examines qualitative and quantitative risk assessments during shutdown plant states, providing feedback to utilities in the use of qualitative models for outage risk management, and also providing input to the development of the American Nuclear Society (ANS) Low Power and Shutdown PRA Standard.

Energy Technology Data Exchange (ETDEWEB)

In this paper, a neural networks (NN) based adaptive sliding mode controller (SMC) is introduced. The selection of SMC feedback gains is normally based on one operating point and thus the performance of the controller away from the design operating point is, of necessity, a compromise. The adaptive SMC is proposed to overcome the limitations imposed on the effectiveness of the SMC under different operating conditions. Neural networks are used for online prediction of the optimal SMC gains when the operating point changes. The proposed method has been applied to a power system stabilizer (PSS) of a single machine power system. Simulation results are included to demonstrate the performance of the proposed control scheme.

Energy Technology Data Exchange (ETDEWEB)

The present invention is a fully connected feed forward network that includes at least one hidden layer 16. The hidden layer 16 includes nodes 20 in which the output of the node is fed back to that node as an input with a unit delay produced by a delay device 24 occurring in the feedback path 22 (local feedback). Each node within each layer also receives a delayed output (crosstalk) produced by a delay unit 36 from all the other nodes within the same layer 16. The node performs a transfer function operation based on the inputs from the previous layer and the delayed outputs. The network can be implemented as analog or digital or within a general purpose processor. Two teaching methods can be used: (1) back propagation of weight calculation that includes the local feedback and the crosstalk or (2) more preferably a feed forward gradient decent which immediately follows the output computations and which ...

Energy Technology Data Exchange (ETDEWEB)

A characteristic trait of Francis turbines operating at low-head is pressure pulsations that occur during certain load levels of the generator. These stem from pressure variations across the turbine due to pulsating flow in the draft-tube. This surging action of the water column is related to draft-tube geometry and flow-rate of water in the penstock. The pressure pulsations cause torque variations on the turbine and corresponding electric power pulsations. If electric power is used as a feedback signal to the Power System Stabilizer (PSS), then Mvar and terminal voltage pulsations will occur when the generator is operating in the ``rough zone``. This paper describes field test results for investigating feedforward control from the penstock, draft tube and spiral case pressure to reduce the effects of Mw pulsations on PSS output signals. This investigation involved a PSS with generator power as the ...

Energy Technology Data Exchange (ETDEWEB)

We have studied the effects of temperature fluctuations on the Advanced Light Source (ALS). By modeling the storage ring support structure, we find that fluctuations of {plus minus}2 to 3deg C in the tunnel will cause photon beam motion of the order of the beam size. Temperature stabilization at this level will allow the residual motion of the photon beams to be reduced by a second level of active feedback, operating on signals from photon beam position monitors. Air temperature in the experimental area and the temperature of cooling water serving the beamlines should be constant to {plus minus}1deg C. This will provide a suitable environment for experiments. (orig.).

Science.gov (United States)

A hyperbolic Stefan problem based on the linearized Gurtin-Pipkin heat conduction law is considered. The temperature and free boundary are controlled by a thermostat acting on the boundary. This feedback control is based on temperature measurements performed by real thermal sensors located within the domain containing the two-phase system and/or at its boundary. Three different types of thermostats are analyzed: simple switch, relay switch, and a Preisach hysteresis operator. The resulting models lead to integrodifferential hyperbolic Stefan problems with nonlinear and nonlocal boundary conditions. Existence results are proved in all the cases. Uniqueness is also shown, except in the situation corresponding to the ideal switch.

Energy Technology Data Exchange (ETDEWEB)

This paper describes the results obtained from two large experimental facilities built at Sandia National Laboratories in Albuquerque, NM. FLAME (Flame Acceleration Measurements and Experiments) is a large horizontal rectangular channel designed to study flame acceleration, transition to detonation, simulation of combustion in containment geometries, component heating, and other problems in hydrogen combustion relevant to reactor safety. The Heated Detonation Tube has been designed to study detonations in hydrogen-air-steam mixtures. Both facilities have been in operation for just over a year. 12 figures.

Energy Technology Data Exchange (ETDEWEB)

Polarized electron sources for high energy accelerators took a significant step forward with the introduction of a new laser-driven photocathode source for the SLC in 1992. With an electron beam polarization of >80% and with {approximately}99% uptime during continuous operation, this source is a key factor in the success of the current SLC high-energy physics program. The SLC source performance is used to illustrate both the capabilities and the limitations of solid-state sources. The beam requirements for future colliders are similar to that of the SLC with the addition in most cases of multiple-bunch operation. A design for the next generation accelerator source that can improve the operational characteristics and at least minimize some of the inherent limitations of present sources is presented. Finally, the possibilities for producing highly polarized electron beams for ...

Energy Technology Data Exchange (ETDEWEB)

The purpose of this paper is to present a summary of new methods, employing Lie algebraic tools, for characterizing beam dynamics in charged-particle optical systems. These methods are applicable to accelerator design, charged-particle beam transport, electron microscopes, and also light optics. The new methods represent the action of each separate element of a compound optical system, including all departures from paraxial optics, by a certain operator. The operators for the various elements can then be concatenated, following well-defined rules, to obtain a resultant operator that characterizes the entire system. This paper deals mostly with accelerator design and charged-particle beam transport. The application of Lie algebraic methods to light optics and electron microscopes is described elsewhere (1, see also 44). To keep its scope within reasonable bounds, they restrict their ...

International Nuclear Information System (INIS)

Safety-related instrument in nuclear power plants must be checked for reliability over their projected operating life. A method of conducting accelerated aging tests is presentd. It uses the Arrhenius activation energy concept and manipulation of the parameters of the test e.g. by raising test temperature, by relying on a model characterizing the chemical-related reactions of materials.

Energy Technology Data Exchange (ETDEWEB)

A compact proton accelerator for medical applications is being developed at Lawrence Livermore National Laboratory. The accelerator architecture is based on the dielectric wall accelerator (DWA) concept. One critical area to consider is the switch region. Electric field simulations and thermal calculations of the switch area were performed to help determine the operating limits of rmed SiC switches. Different geometries were considered for the field simulation including the shape of the thin Indium solder meniscus between the electrodes and SiC. Electric field simulations were also utilized to demonstrate how the field stress could be reduced. Both transient and steady steady-state thermal simulations were analyzed to find the average power capability of the switches.

International Nuclear Information System (INIS)

TAPP-3 and 4 reactors use large number of Self Powered Neutron Detectors (SPNDs) for Neutronic lower measurement and control. To perform in-situ calibration of these detectors in select locations and to validate the reactor physics codes which predict flux at various points in the core, traveling in-core probes (TIP) are required. The TIP assembly consists of a miniature neutron sensitive detector. The detector is driven in and out of core using a mechanism which facilitates positioning of the detector anywhere inside a vertical tube (Central carrier tube of any of the six select Vertical Flux Units) in the core. TIP is driven through retractable feed mechanism for a stroke of 13 m. This paper describes the developmental efforts and the operational feedback of the retractable feed mechanism for the stroke of 13 m used at TAPP 3 and 4 reactor. (author)

International Nuclear Information System (INIS)

The automatic real-time system operating at the LU-10 linac and providing measurements of the parameters such as the beam current (average and pulse values), the electron energy, the linear density distribution of beam current, and also the conveyor speed is described in the paper.

Energy Technology Data Exchange (ETDEWEB)

Particle physics is driven by five great topics. Neutrino oscillations and masses are now at the fore. The standard model with extensions to supersymmetry and a Higgs to generate mass explains much of the field. The origins of CP violation are not understood. The possibility of extra dimensions has raised tantalizing new questions. A fifth topic lurking in the background is the possibility of something totally different. Many of the questions raised by these topics require powerful new accelerators. It is not an overstatement to say that for some of the issues, the accelerator is almost the experiment. Indeed some of the questions require machines beyond our present capability. As this volume attests, there are parts of the particle physics program that have been significantly advanced without the use of accelerators such as the subject of neutrino oscillations and many aspects of the particle-cosmology interface. At this ...

International Nuclear Information System (INIS)

The fusion materials program has little irradiation effects data at temperatures from 100 to 350 degree C. Near-term machines such as the International Thermonuclear Engineering Reactor (ITER) will expose materials to neutron doses of 38 to 50 dpa at 150 degree C or less. The data base for structural materials must be extended into this range. Also, lower temperatures are needed to investigate the lower bound for tritium release from solid breeder materials. A low temperature test vehicle is proposed for the Fast Flux Test Facility (FFTF), which will provide test temperatures of 100 to 350 degree C. An 8.5-cm dia. by 100-cm test volume will be instrumented to collect temperature data and provide feedback for control. The spectrum and flux will provide accelerated damage accumulation for structural materials testing and the best available approximation of fusion reactor conditions for solid breeder materials testing. Breeder samples can be ...

Energy Technology Data Exchange (ETDEWEB)

A stable power system stabilizer (PSS) based on the inverse dynamics of the controlled system using an artificial neural network (ANN) is suggested to enhance the dynamic performances of a power system. First, an output feedback control law is driven with some conditions satisfied, which guarantees the internal stability and robustness against the asymptotically stable external disturbances. Then the control law is implemented using the inverse dynamics of the controlled plant. The inverse dynamics of the controlled plant is identified by an ANN, inverse dynamics neural network (IDNN), off-line. The pole-shifting technique and a scaling factor are introduced for the control system to meet the conditions for internal stability and robustness. The proposed controller is applied to a typical single-machine infinite-bus power system. Simulation results under various operation conditions are given which show that the proposed controller damps the ...

Energy Technology Data Exchange (ETDEWEB)

In this paper the newly developed discrete-time adaptive sliding mode control method is proposed and applied to the power system stabilization problem. In contrast to the conventional continuous-time sliding mode controller, the proposed method is developed in the discrete-time domain and based on the input/output measurements instead of the continuous-time and the full-states feedback, respectively. Because the proposed control method has the adaptivity property in addition to the natural robustness property of the sliding mode control, it is possible to design the power system stabilizer which can overcome both the minor variations of the parameters of the power system and the diverse operating conditions and faults of the power system. Mathematical proof and the various computer simulations are done to verify the performance and stability of the proposed method. (author). 14 refs., 12 figs., 1 tab.

International Nuclear Information System (INIS)

The paper presents the investigations of plasma streams generated by pulsed plasma gun 'Prosvet' operated with different gases: krypton (m=84) and helium (m=4). Contour parameters of working gas spectral lines (full intensities and half-widths) are used for determination of spatial distributions of the electron density and temperature. Temporal distributions of the spectral lines intensities (both neutrals and ions of working gas), impurity spectral lines and continuum intensities are analyzed. Plasma stream velocity was estimated by time-of-flight method between two monochromators (MUM) connected with photo-multiplier. longitudinal distributions of the plasma pressure for different time moments and varied distances from the accelerator output have been used for investigation of the plasma stream dynamics and study the plasma compression in the focus region for different operational regimes of plasma ...

Energy Technology Data Exchange (ETDEWEB)

The Tevatron is a proton anti-proton accelerator collider operating at the Fermi National Accelerator Laboratory. The machine is currently delivering beam for the CDF and D0 experiments, which expect increasing luminosity until the conclusion of Run II, planned for 2009. The Laboratory defined a plan for achieving higher luminosity, and one of the tasks is the upgrade of the accelerator's beam position monitor (BPM). The Tevatron was built during the early eighties and some of its control systems, including the BPMs, are still the original ones. This paper describes the front-end software of the Tevatron BPM upgrade, from the requirements to the implementation, and the underlying hardware setup. The front-end software designed is presented, emphasizing its modularity and reusability, allowing it to be applied to other Fermilab machines.

CERN Document Server

Luminosity-driven channeling extraction has been observed for the first time in a 900 GeV study at the Fermilab Tevatron. This experiment, Fermilab E853, demonstrated that useful TeV level beams can be extracted from a superconducting accelerator during high luminosity collider operations without unduly affecting the background at the collider detectors. Multi-turn extraction was found to increase significantly the efficiency of the process. The beam extraction efficiency was about 25%. Studies of time dependent effects found that the turn-to-turn structure was governed mainly by accelerator beam dynamics. An investigation of a pre-scatterer using the accelerator flying wire system showed that a fiber could produce a significant extracted flux, consistent with expectations. Based on these results, it is feasible to construct a parasitic 5-10 MHz proton beam from the Tevatron collider.

Energy Technology Data Exchange (ETDEWEB)

The performance of bunch-feedback systems based on two-tap FIR filters is discussed, particularly for transverse cases. Since they are the simplest type of FIR digital filters, the two-tap FIR filters should be suited to systems that require a very fast processing speed. However, in these feedback systems, a bunch must turn along a ring several times from the position-measurement to feedback kicking. Within these turns, irregular phase-jumps in the betatron motion can occur, due to several causes, such as the wake forces and beam-beam force. The discussion given in this paper is focussed on the effect of beam-beam collisions on these feedback systems. Based on linear theory and simulation studies, it has been found that these feedback systems can work with good performance, even under the influence of a strong beam-beam force. (author)

International Nuclear Information System (INIS)

The Cycle 8A static tests conducted in the Fast Flux Test Facility (FFTF) during 1986 have resulted in the separation of various feedback reactivity components. These feedback components, described by closed-form equations depending only on the reactor temperature field, can be regarded as database for the validation and/or calibration of feedback mechanistic models. The SASSYS safety analysis code contains the most developed feedback reactivity models and was selected for the comparison study between database and mechanistic calculations for the FFTF. Although detailed feedback models for control rod repositioning and core radial expansion/bowing exist, only the simple models were available in SASSYS at the time of this study. The results are described in this paper.

International Nuclear Information System (INIS)

The Fast Flux Test Facility (FFTF) was designed to test fast-reactor fuels and other nonfuel materials. In its 37 reactor cycles of operations, the FFTF reactor has performed very well and successfully completed all the irradiation testings with an operating efficiency factor as high as 98%. Since FFTF is an experimental reactor, its core loading changed from cycle to cycle. Depending on the number of test assemblies in the core and their location, the core loading can change significantly from an essentially homogeneous core loading to a relatively nonhomogeneous or even highly localized heterogeneous loading. Consequently, the core reload design and initial criticality analyses were required for each operating cycle. The zero power initial critical control rod bank height was predicted before each reactor startup. The initial critical prediction depends on the reactivity conditions at the end of the previous cycle, the ...

Energy Technology Data Exchange (ETDEWEB)

An analysis of the current state of track-laying operations in open-cut mines is given and their labor intensive nature is noted. The lag in the technological development of mechanization equipment for track laying and repair operations is noted. Results are given from developments by the Scientific Research Institute of Open-Pit Mining Operations in the field of mobile transportation technology and promising modular route design. Also examined are the problems of improving the routing bases in the industry. The absence of factories for manufacturing transportation technology and equipment is reflected most evidently in the technical and cost characteristics of coal production by an open-cut method and requires immediate solution.

Energy Technology Data Exchange (ETDEWEB)

Diesel passenger car is superior to gasoline engine car in the fuel economy, but it has some defects to improve: noise, startability, particulate and transient performance, etc. Among these problems, this paper presents particularly transient performance in a diesel engine and clarifies the causes of its decline at lower temperature operation. As the results, it is found that the transient torque at the early stage of acceleration is only 50% at -20/sup 0/C, and that when coolant temperature went up to 20/sup 0/C, the transient torque approaches to that of the warmed up engine. The transient response become worse with retarding the injection timing and with decreasing the engine speed. On the other hand, since the normal response is not obtained despite using high cetane number fuel, main cause of the inferior transient torque is not the poor combustion, but the increase of friction or cooling loss.

Energy Technology Data Exchange (ETDEWEB)

Four interrelated projects are underway whose purpose is to migrate the LAMPF-PSR Accelerator Complex control systems to a system with a common set of hardware and software components. Project goals address problems in performance, maintenance and growth potential. Front-end hardware, operator interface hardware and software, computer systems, network systems and data system software are being simultaneously upgraded as part of these efforts. The efforts are being coordinated to provide for a smooth and timely migration to a client-sever model-based data acquisition and control system. An increased use of the distributed intelligence at both the front-end and operator interface is a key element of the projects. 2 refs., 2 figs.

CERN Document Server

We apply the potential force estimation method to artificial time series of market price produced by a deterministic dealer model. We find that dealers' feedback of linear prediction of market price based on the latest mean price changes plays the central role in the market's potential force. When markets are dominated by dealers with positive feedback the resulting potential force is repulsive, while the effect of negative feedback enhances the attractive potential force.

Energy Technology Data Exchange (ETDEWEB)

Stabilization of the particle beam position with respect to the focusing optics in the third generation synchrotron light sources is crucial to achieving low emittance and high brightness. For this purpose, global and local beam orbit correction feedbacks will be implemented in the APS storage ring. In this article, the authors discuss application of digital signal processing to particle/photon beam position feedback using the PID (proportional, integral, and derivative) control algorithm.

Energy Technology Data Exchange (ETDEWEB)

The Fermilab Linac Upgrade is planned to increase the energy of the H- linac from 200 to 400 MeV. This is intended to reduce the incoherent space-charge tuneshift at injection into the 8 GeV Booster which can limit either the brightness or the total intensity of the beam. The Linac Upgrade will be achieved by replacing the last four 201.25 MHz drift-tube tanks which accelerate the beam from 116 to 200 MeV, with seven 805 MHz side-coupled cavity modules operating at an average axial field of abut 7.5 MV/m. This will allow acceleration to 400 MeV in the existing Linac enclosure. Each accelerator module will be driven with a klystron-based rf power supply. A prototype rf modulator has been built and tested at Fermilab, and a prototype 12 MW klystron is being fabricated by Litton Electron Devices. Fabrication of production accelerator modules is in progress. 8 figs., 4 tabs.

International Nuclear Information System (INIS)

This report discusses the safety approach of the Advanced Liquid Metal reactor program, sponsored by the US Department of Energy, which relies upon passive reactor responses to off-normal condition to limit power and temperature excursions to levels that allow safety margins. Gas expansion modules (GEM) have included in the design to provide negative reactivity to enhance these margins in the extremely unlikely event that pumping power is lost and the highly reliable scram system fails to operate. The feasibility and beneficial features of these devices were first demonstrated in the core of the Fast Flux Test Facility (FFTF) in 1986. Preapplication safety evaluations by the US Nuclear Regulatory Commission have identified areas that must be addressed if these devices are to be relied on. One of these areas is the response of the reactor when it is critical and the pumps are turned on, resulting in positive reactivity being added to the core. Tests to examine such ...

International Nuclear Information System (INIS)

Elise is a heavy ion induction linear accelerator that will demonstrate beam manipulations required in a driver for inertial fusion energy. With a line charge density similar to that of heavy ion drivers, Elise will accelerate a #>=# 1 gs beam pulse of K"+ ions from an initial energy of 2 MeV to a final energy #>=# 5 MeV. In the present design, the Elise electrostatic quadrupoles (ESQ) will have a 2.33 cm radius aperture operating at #+-#59 kV. The half-lattice periods range from 21 cm to 31 cm. The entire machine will be approximately 30 m long, half of that is the induction accelerator and the remaining half is the injector (including the Marx generator) and the matching section. Elise will be built in a way that allows future expansion into the full ILSE configuration, therefore it will have an array of four ESQ focusing channels capable of transporting up to a total of 3.2 A of beam current. ...

Energy Technology Data Exchange (ETDEWEB)

The present emphasis on inherent safety for LMR designs has resulted in a need to represent the various reactivity feedback mechanisms as accurately as possible. The dominant negative reactivity feedback has been found to result from radial expansion of the core for most postulated ATWS events. For this reason, a more detailed model for calculating the reactivity feedback from radial core expansion has been recently developed for use with the SASSYS/SAS4A Code System. The purpose of this summary is to present an extension to the model so that it is more suitable for handling a core restraint design as used in FFTF, and to compare the SASSYS/SAS4A results using this model to the empirical correlation presently being used to account for radial core expansion reactivity feedback to FFTF.

Energy Technology Data Exchange (ETDEWEB)

Short communication.

International Nuclear Information System (INIS)

Short communication.

Energy Technology Data Exchange (ETDEWEB)

A summary of the topics covered in papers presented at the 1995 Brookhaven joint conference on production, neutralization, and application of negative ion beams is given. The conference topics covered included plasma ion sources, plasma seeding of these sources for increased ion production, beam extraction and transport, computer simulation and design studies, and operation of existing and experimental ion source facilities. Application of the sources to accelerator, tokamak, and thin film deposition are discussed. (AIP) {copyright} {ital 1996 American Institute of Physics.}

Energy Technology Data Exchange (ETDEWEB)

Research performed at LAMPF during 1985 is reported in the areas of: nuclear and particle physics; atomic and molecular physics; materials science; radiation-effects studies; biomedical research and instrumentation; nuclear chemistry; radioisotope production; and physics theory. Also reported are the status of LAMPF-II, facility development work, and accelerator operations. (LEW)

Energy Technology Data Exchange (ETDEWEB)

A polarized proton physics run took place during January, 1988, at the Brookhaven AGS. It is the purpose of this paper to review the tune-up period preceding that run. This was the third such run at the AGS; the others occurred in June of 1984 and February of 1986. Some comparisons will be drawn among these. A thorough review of the history and hardware associated with the acceleration of polarized protons at the AGS can be found in the proceedings of the last meeting of this group at Protvino and will not be repeated here. 2 refs., 6 figs., 1 tab.

International Nuclear Information System (INIS)

This report is a brief review of biological and medical applications of ion-track membranes. The review aims at informing nuclear physicists about alternative (i.e. non-fundamental-science) use of heavy ion accelerators such as production of micro- and nano-porous materials. The ion-track membranes produced this way are employed in life sciences and numerous technological applications. The author focuses on recent results from the Flerov laboratory in co-operation with other scientific institutions and industrial partners.

International Nuclear Information System (INIS)

A 10.6-micron wavelength free-electron laser (FEL) amplifier has been operated using a 45-MeV, 600-A electron beam from the Advanced Test Accelerator (ATA) and a 15.36-meter long electromagnetic wiggler. The peak small signal power gain was 27 dB(500). Gain guiding was observed to confine the amplified laser beam.

Energy Technology Data Exchange (ETDEWEB)

The authors present design methodology and initial experimental results for a high power microwave switch. The switch is designed for application to the pulse compression system associated with the Next Linear Collider Test Accelerator (NLCTA). The switch is based on the excitation of a plasma layer within a silicon wafer by either a laser or an electron beam. They investigate problems associated with high power operation of such a switch. They explore solutions to the problems of thermal runaway, avalanche breakdown, photo-emission, and secondary emission.

Energy Technology Data Exchange (ETDEWEB)

Precondition for the low-NO operation of gas turbine burners is the generation of as homogeneous as possible a gaseous fuel/air mixture. Such a burner behavior can be achieved by selective adaptation of the flow and injection. A computing model is introduced that calculates the dynamically balanced GASs/droplet flow through numerical solution of the transport equations in a curved orthogonal coordinate system. The feedback reaction of the fuel droplets to the gas phase is considered by source terms and/or sink terms. Test computations were carried out for comparison with analytical solutions from the flow mechanics and validated by comparison with measurement results. Droplet motion and evaporation were checked by means of published experimental results on single droplets. For the validation of the developed computing technique, model tests were carried out with water in place of fuel. It is pointed out that the choice of different parameters ...

Energy Technology Data Exchange (ETDEWEB)

Inherent safety tests were performed during 1986 in the 400-MW (thermal) Fast Flux Test Facility (FFTF) reactor to demonstrate the effectiveness of an inherent shutdown device called the gas expansion module (GEM). The GEM device provided a strong negative reactivity feedback during loss-of-flow conditions by increasing the neutron leakage as a result of an expanding gas bubble. The best-estimate pretest calculations for these tests were performed using the IANUS plant analysis code (Westinghouse Electric Corporation proprietary code) and the MELT/SIEX3 core analysis code. These two codes were also used to perform the required operational safety analyses for the FFTF reactor and plant. Although it was intended to also use the SASSYS systems (core and plant) analysis code, the calibration of the SASSYS code for FFTF core and plant analysis was not completed in time to perform pretest analyses. The purpose of this paper is to present the results ...

International Nuclear Information System (INIS)

This work aims at improving the understanding of the dynamics of a Free Electron Laser (FEL) based on a storage ring. A new phenomenon of saturation by the electron bunch transverse dimensions is pointed out, during the FEL operation with a magnetic optics ''low emittance''. A part of this thesis work concerns the study of the longitudinal dynamics of the FEL depending on a parameter: the detuning between the pass frequency of the electrons and the back and return frequency of the laser pulse in the optical cavity. This study shows that the FEL presents a pulsed or a steady state behavior depending on the detuning. Besides, a spectro-temporal behavior of the FEL is pointed out showing the FEL pulse substructures and holes in the spectrum. Another part of this work concerns the response of the resonant FEL system, when a perturbation is applied on the gain. Under the effect of a modulation, the FEL can present a periodic or chaotic regime. The analysis of these ...

Energy Technology Data Exchange (ETDEWEB)

At Los Alamos, we are building a free-electron laser (FEL) for industrial, medical, and research applications. This FEL, which will incorporate many of the new technologies developed over the last decade, will be compact in size, robust, and user-friendly. Electrons produced by a photocathode will be accelerated to 20 MeV by a high-brightness accelerator and transported using permanent-magnet quadrupoles and dipoles. They will form an electron beam with an excellent instantaneous beam quality of 10 {pi} mm mrad in transverse emittance and 0.3% in energy spread at a peak current up to 300 A. Including operation at higher harmonics, the laser wavelength extends form 3.7 {mu}m to 0.4 {mu}m. In this paper, we will describe the project and the programs to date. 10 refs., 10 figs., 1 tab.

Energy Technology Data Exchange (ETDEWEB)

The authors report experimental results on a high gradient 17 GHz RF photocathode gun. The photocathode RF gun is a novel electron beam source intended to meet the requirements set by future high-energy linear colliders and next generation free electron lasers. A coupled pair of pillbox TM{sub 010}-like resonators is excited by sidewall coupled microwaves at 17 GHz. A picosecond ultraviolet laser pulse illuminates one wall of the structure at the axis of symmetry. Electrons are released by the photoelectric effect and are accelerated by the electric field of the microwaves in the cavity. The high frequency of operation raises the RF breakdown limit allowing strong electric fields to be used. In turn, the intense fields result in rapid acceleration of the electrons to relativistic speeds and reduced space charge induced emittance growth.

Energy Technology Data Exchange (ETDEWEB)

This paper describes the specifications, conceptual design, prototype testing and operating experience of an oil-filled high voltage pulse transmission cable adapted from commercially available air-dielectric RF components. Lawrence Livermore National Laboratory's Advanced Test Accelerator (ATA) requires a method of transmitting 250kV, 70 nanosecond pulses from the power conditioning equipment to the accelerator. The oil-filled cable approach was chosen over alternative concepts because of its high voltage holding capacity, long life and flexibility. The criteria for cable and connector design are discussed. The results of prototype testing and performance of the final design are presented.

CERN Document Server

First Result of Induction Acceleration in the KEK Proton Synchrotron

International Nuclear Information System (INIS)

We consider the possibility of a cyclotron-autoresonance-maser (CARM) klystron configuration for accelerator applications as an alternative to the gyroklystron amplifier. The potential advantages, compared to gyroklystrons, include: 1) comparable efficiencies at lower values of the electron beam pitch ratio #alpha#, which should improve the beam quality and make the device substantially more stable against the excitation of parasitic mode, 2) operation far from cutoff, which should reduce the fields at cavity walls, allowing higher power operation, and 3) operation at lower magnetic fields for the same cyclotron harmonic number. However, there are two significant issues associated with the design of efficient, high-power CARMs. First, because of the higher value of k_Z, compared to gyroklystrons, CARMs are substantially more sensitive to parallel velocity spread (pitch-angle spread). Second, ...

International Nuclear Information System (INIS)

The FEL electron linac consists of three buncher cavities: two accelerator cavities and a deflection cavity, each with its own phase-coherent rf source. All sources will be pulsed for 100 #mu#s at a 1-pps rate. The phase and amplitude stability requirements are +-1/2_0, and +-1/2%. There are two subharmonic bunchers, each requiring 5 kW at 108.33 MHz. All remaining cavities operate at 1300 MHz. The fundamental buncher requires 5 kW, whereas each of the accelerating cavities requires at least 3 MW. The deflection cavity requires up to 100 kW, which is coupled from one of the accelerator cavity rf sources. Prominent features of the rf system are the phase and amplitude control circuits and the multimegawatt klystron amplifiers. Three L3707 klystrons were obtained from the AMRAD radar site at White Sands, which was decommissioned in the early 1970s. The tubes originally were designed to produce 10-MW, ...

International Nuclear Information System (INIS)

The FEL electron linac consists of three buncher cavities: two accelerator cavities and a deflection cavity, each with its own phase-coherent rf source. All sources will be pulsed for 100 #mu#s at a 1-pps rate. The phase and amplitude stability requirements are + or - 1/2"0, and + or - 1/2%. There are two subharmonic bunchers, each requiring 5 kW at 108.33 MHz. All remaining cavities operate at 1300 MHz. The fundamental buncher requires 5 kW, whereas each of the accelerating cavities requires at least 3 MW. The deflection cavity requires up to 100 kW, which is coupled from one of the accelerator cavity rf sources. Prominent features of the rf system are the phase and amplitude control circuits and the multimegawatt klystron amplifiers. Three L3707 klystrons were obtained from the AMRAD radar site at White Sands, which was decommissioned in the early 1970s. The tubes originally were designed to produce ...

International Nuclear Information System (INIS)

In this paper the authors present a design study on the longitudinal dynamics of a relativistic klystron two-beam accelerator (RK-TBA) scheme which has been proposed as a power source candidate for a 1 TeV next linear collider (NLC). They address the issue of maintaining stable power output at desired level for a 300-m long TBA with 150 extraction cavities and present their simulation results to demonstrate that it can be achieved by inductively detuning the extraction cavities to counter the space charge debunching effect on the drive beam. They then carry out simulation study to show that the beam bunches desired by the RK-TBA can be efficiently obtained by first chopping an initially uniform beam of low energy into a train of beam bunches with modest longitudinal dimension and then using the open-quotes adiabatic captureclose quotes scheme to bunch and accelerate these beam bunches into tight bunches at the operating ...

International Nuclear Information System (INIS)

Complete calculations of the accelerator related background in the muon spectrometer of the CMS detector at the Large Hadron Collider are presented. The simulations have been performed with the STRUCT multi-turn tracking code and the MARS and FLUKA cascade codes taking into account latest information of the LHC lattice, vacuum conditions, beam cleaning system and the shielding and layout of the CMS experiment. Beam loss distributions in the interaction regions and their vicinities and their contribution to the background levels in the muon spectrometer of CMS are analyzed. The studies show that hadronic and electromagnetic components of machine background are efficiently suppressed by the proposed CMS shielding. High energy muons penetrate through the shielding, but in positions of significance they do not contribute more than a few percent compared to the background generated by the pp-collisions. It is anticipated that the relative contribution of ...

CERN Document Server

While feedback is important in theoretical models, we do not really know if it works in reality. Feedback from jets appears to be sufficient to keep the cooling flows in clusters from cooling too much and it may be sufficient to regulate black hole growth in dominant cluster galaxies. Only about 10% of all quasars, however, have powerful radio jets, so jet-related feedback cannot be generic. The outflows could potentially be a more common form of AGN feedback, but measuring mass and energy outflow rates is a challenging task, the main unknown being the location and geometry of the absorbing medium. Using a novel technique, we made first such measurement in NGC 4051 using XMM data and found the mass and energy outflow rates to be 4 to 5 orders of magnitude below those required for efficient feedback. To test whether the outflow velocity in NGC 4051 is unusually low, we compared the ...

International Nuclear Information System (INIS)

The strong coupling of subsystem elements, such as the accelerator, wiggler, and optics, greatly complicates the understanding and design of a free electron laser (FEL), even at the conceptual level. To address the strong coupling character of the FEL the concept of an Integrated Numerical Experiment (INEX) was proposed. Unique features of the INEX approach are consistency and numerical equivalence of experimental diagnostics. The equivalent numerical diagnostics mitigates the major problem of misinterpretation that often occurs when theoretical and experimental data are compared. The INEX approach has been applied to a large number of accelerator and FEL experiments. Overall, the agreement between INEX and the experiments is very good. Despite the success of INEX, the approach is difficult to apply to trade-off and initial design studies because of the significant manpower and computational requirements. On the other hand, INEX provides a base ...

Science.gov (United States)

... This must be taken a step further in counseling and other feedback and ... Record System Power Point Presentation ,www.armyppt.com/ncoer/6.htm ...

UK PubMed Central (United Kingdom)

Diverse cell polarity networks require positive feedback for locally amplifying distributions of signalling molecules at the plasma membrane1. Additional...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The main physical processes allowing negative ion production by surface sputtering for further acceleration in tandem acceleration are briefly reviewed. The sputtering yield and the probability of negative ion ejection are discussed. The properties of negative ion beams for an efficient acceleration in tandem accelerators are also discussed, with an emphasis on space charge problems. The main features and performances of the heavy negative ion injector of the Bucharest tandem accelerator are given.

Energy Technology Data Exchange (ETDEWEB)

Research highlights: {yields} Mathematical model represents a power system which consists of synchronous machine connected to infinite bus through transmission line. {yields} Power system stabilizer was designed based on optimal pole shifting controller. {yields} The system performances was tested through load disturbances at different operating conditions. {yields} The system performance with the proposed optimal pole shifting controller is compared with the conventional pole placement controller. {yields} The digital simulation results indicated that the proposed controller has a superior performance. -- Abstract: Power system stabilizer based on optimal pole shifting is proposed. An approach for shifting the real parts of the open-loop poles to any desired positions while preserving the imaginary parts is presented. In each step of this approach, it is required to solve a first-order or a second-order linear matrix Lyapunov equation for shifting one real pole or ...

International Nuclear Information System (INIS)

Research highlights: ? We model power oscillations in boiling water reactors using a lumped parameter model. ? The nature and amplitudes of oscillations is obtained using a nonlinear analysis. ? The method of multiple scales has been used for the analytical treatment. ? Fuel temperature coefficient of reactivity determines the nature of oscillations. ? The presented systematic method of analysis useful for reduced order reactor models. - Abstract: In this paper, we perform a parametric study of the nonlinear dynamics of a reduced order model for boiling water reactors (BWR) near the Hopf bifurcation point using the method of multiple scales (MMS). Analysis has been performed for general values of the parameters, but the results are demonstrated for parameter values of the model corresponding to the advanced heavy water reactor (AHWR). The neutronics of the AHWR is modeled using point reactor kinetic equations while a one-node lumped parameter model is assumed both for the fuel and the ...

Energy Technology Data Exchange (ETDEWEB)

This paper describes potentials on fuel economy and NO{sub x} exhaust emissions of a series hybrid urban bus system equipped with a ceramic gas turbine engine (CGT). The simulating program developed in-house was used to analyze influences of several parameters of each main components of the hybrid vehicle system on the performance of the bus running on the modified bus driving cycle. The basic data used in this analysis for a CGT was derived from the results of 'the Automotive 100kW CGT Project' of Japan. A dynamic response of a CGT-Generator rotating system was very much improved by introducing of 'Assisting system' in which the generator was used as an acceleration-deceleration assisting device when much acceleration or deceleration was needed. This system would make a CGT operate along the optimum operating line (fuel minimum line) even under the unsteady driving ...

Energy Technology Data Exchange (ETDEWEB)

The Fermilab Steering Group has developed a plan to keep U.S. accelerator-based particle physics on the pathway to discovery, both at the Terascale with the LHC and the ILC and in the domain of neutrinos and precision physics with a high-intensity accelerator. The plan puts discovering Terascale physics with the LHC and the ILC as Fermilab's highest priority. While supporting ILC development, the plan creates opportunities for exciting science at the intensity frontier. If the ILC remains near the Global Design Effort's technically driven timeline, Fermilab would continue neutrino science with the NOVA experiment, using the NuMI (Neutrinos at the Main Injector) proton plan, scheduled to begin operating in 2011. If ILC construction must wait somewhat longer, Fermilab's plan proposes SNuMI, an upgrade of NuMI to create a more powerful neutrino beam. If the ILC start is postponed significantly, a ...

International Nuclear Information System (INIS)

A variable-dispersion electron spectrometer is being installed for use by the Stanford Superconducting Accelerator in conjunction with its Free Electron Laser program. The system has been designed to operate with electron beam energies from 20 MeV to 200 MeV, with a maximum energy resolution of 0.01% FWHM. The maximum energy acceptance is approximately #+-# 5%, as determined by the bending magnet aperture. Resolution is controlled by adjusting the focal conditions at the entrance to a 90 degree bending magnet, while the dispersion is controlled by changing the magnitude and polarity of the field in a quadrupole magnet which immediately follows the bending magnet. 4 refs., 5 figs.

Energy Technology Data Exchange (ETDEWEB)

The NuMI proton beam at Fermilab currently delivers 120 GeV protons to the neutrino production target with design beam power capability to 400 kW. Upgrade capability to 700 kW is being prepared, with planning toward delivering 2.3 MW beam provided by the Project X accelerator upgrade plan. We report on the system of beam diagnostics and control used in operation of the NuMI beam. Also considered are the steps to provide a robust system for transport and targeting beam of 2 MW and beyond.

British Library Electronic Table of Contents (United Kingdom)

We operate a new NEC 250kV single-stage accelerator mass spectrometer (SSAMS) next to our established 5MV tandem. This permits good comparison of 14C-AMS and challenges SSAMS performance. Initial SSAMS ion-optical deficiencies have been addressed by shimming the injection magnet and 3permil 14C/13C measurement with background limited by sample chemistry is routine. Higher-precision analysis is also achievable. A problematic measurement interference remains, however. The small spectrometer was procured to add measurement capacity, and for experiments with positive ions, but is now the preferred instrument for both convenience and measurement quality.

International Nuclear Information System (INIS)

The sensitivity of the primary circuit material was examined at the Mochovce and Dukovany NPPs. No significant sensitivity of the base material or the weld metal to the initiation of corrosion cracking was observed. Thermal aging was found to accelerate significantly the corrosion fatigue kinetics in the material of the heat affected zone. The threshold values of the double amplitudes of the stress intensity factor were below 8 MPa/m"2 for the materials examined, with a cycle asymmetry coefficient of 0.65. The tests revealed no appreciable sensitivity to general corrosion, pitting, or intergranular corrosion. (J.B.). 7 tabs., 26 figs., 11 refs.

International Nuclear Information System (INIS)

A family of industrial irradiators is being developed by AECL to cover an electron-beam energy range from 5 to 18 MeV at beam powers between 20 and 250 kW. The IMPELA family of irradiators is designed for push button, reliable operation. The major irradiator components are modular, allowing for later upgrades to meet increased demands in either electron or X-ray mode. Interface between the control system, irradiator availability and dose quality assurance is in conformance with the most demanding specifications. The IMPELA irradiators use a klystron-driven, standing-wave, L-band accelerator structure with direct injection from a rugged, triode electron gun. Direct control of the accelerating field during the beam pulse ensures constant output beam energy, independent of beam power. The first member of the family, the IMPELA 10/50 (10 MeV, 50 kW), is in the final stages of assembly at Chalk River Nuclear Laboratories. The ...

Energy Technology Data Exchange (ETDEWEB)

We describe a global closed orbit feedback experiment, based upon a real time harmonic analysis of both the orbit movement and the correction magnetic fields. The feedback forces the coefficients of a few harmonics near the betatron tune to vanish, and significantly improves the global orbit stability. We present the results of the experiment in the UV ring using 4 detectors and 4 trims, in which maximum observed displacement was reduced by a factor of between 3 and 4. 4 refs., 3 figs.

CERN Document Server

In the positive column of a neon glow discharge, two different types of ionization waves occur simultaneously. The low-dimensional chaos arising from the nonlinear interaction between the two waves is controlled by a continuous feedback technique. The control strategy is derived from the time-delayed autosynchronization method. Two spatially displaced points of observation are used to obtain the control information, using the propagation characteristics of the chaotic wave.

Energy Technology Data Exchange (ETDEWEB)

The objective of this project is to investigate the applicability of a combined Global Positioning System and Inertial Measurement Unit (GPS/IMU) for information based displays on earthmoving machines and for automated earthmoving machines in the future. This technology has the potential of allowing an information-based product like Caterpillar's Computer Aided Earthmoving System (CAES) to operate in areas with satellite shading. Satellite shading is an issue in open pit mining because machines are routinely required to operate close to high walls, which reduces significantly the amount of the visible sky to the GPS antenna mounted on the machine. An inertial measurement unit is a product, which provides data for the calculation of position based on sensing accelerations and rotation rates of the machine's rigid body. When this information is coupled with GPS it results in a positioning system that can ...

International Nuclear Information System (INIS)

The present emphasis on inherent safety for liquid-metal reactor designs has resulted in a need to represent the various reactivity feedback mechanisms as accurately as possible. The dominant negative reactivity feedback has been found to result from radial expansion of the core for most postulated anticipated transient without scram events. For this reasons, a more detailed model for calculating the reactivity feedback from radial core expansion, including subassembly bowing has been recently developed for use with the SASSYS/SAS4A code system. The purpose of this summary is to present an extension to the model so that it is more suitable for handling a core restraint design as used in the Fast Flux Test Facility (FFTF), and to compare the SASSYS/SAS4A results using this model to the empirical correlation presently being used to account for radial core expansion reactivity feedback in the FFTF.

Energy Technology Data Exchange (ETDEWEB)

Abstract not provided

International Nuclear Information System (INIS)

The UK fully supports the objective of the Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management to achieve and maintain a high level of safety worldwide in spent fuel and radioactive waste management, through the enhancement of national measures and international co-operation, including where appropriate, safety-related co-operation. The UK's Health and Safety Executive, through its Nuclear Safety Directorate (NSD), has been committed to the Convention since the initial negotiations to set up the Convention and provided the president of the first review meeting in 2003. It would be wrong of any nation to believe that they have all the best solutions to managing spent fuel and radioactive waste. The process of compiling reports for the Convention review meetings provides a structured process through which every contracting party can review its provisions against a common set of standards and ...

Science.gov (United States)

In this paper we present some final results from a research project focused on introducing automatic control to the operation of cupola iron furnaces. The main aim of this research is to improve the operational efficiency and performance of the cupola furnace, an important foundry process used to melt iron. Previous papers have described the development of appropriate control system architectures for the cupola. These results are summarized. Then we describe the experimental results obtained with the U.S. Department of Energy Albany Research Center`s research cupola. First, experimental data is used to calibrate the model, which is taken as a first-order multivariable system with time delay. Then relative gain analysis is used to select loop pairings to be used in a multi-loop controller. The resulting controller pairs meltrate with blast volume, iron temperature with oxygen addition, and carbon composition with percent coke. Special ...

International Nuclear Information System (INIS)

In 1999, the plasma parameters of reversed shear (RS) plasmas had been extended in 1) DT-equivalent fusion power gain Q_D_T"e"q - 0.5 (n_D(0)#tau#_ET_i(0) - 4x10"2"0 m"-"3#centre dot#keV#centre dot#s) for 0.8 s and 2) full non-inductive current drive with 80% of the bootstrap current fraction. Physics of the internal transport barriers (ITBs) in RS plasmas, including the energy transport and the formation of ITB, were extensively studied. A nearly full current drive (92% non-inductively) was obtained with negative ion based neutral beam (NNB) injection (360 keV, 3.4 MW) in a high #beta#_p H-mode plasma (I_p=1.5 MA, B_T=3.7 T, q_9_5=4.2) with high plasma performance (#beta#_N=2.4 and H_8_9=2.56). Rise in the central electron temperature (T_e - 9 keV) resulted in the current drive efficiency #eta#_C_D of NNB reached 1.3x10"1"9 A/W/m"2, the highest for the neutral beam current drive. As for the H-mode plasmas, decrease in the pedestal ion temperature due to strong gas was found cause ...

International Nuclear Information System (INIS)

Power extraction using a dielectric-loaded (DL) waveguide is a way to generate high-power radio frequency (RF) waves for future particle accelerators, especially for two-beam-acceleration. In a two-beam-acceleration scheme, a low-energy, high-current particle beam is passed through a deceleration section of waveguide (decelerator), where the power from the beam is partially transferred to trailing electromagnetic waves (wakefields); then with a properly designed RF output coupler, the power generated in the decelerator is extracted to an output waveguide, where finally the power can be transmitted and used to accelerate another usually high-energy low-current beam. The decelerator, together with the RF output coupler, is called a power extractor. At Argonne Wakefield Accelerator (AWA), we designed a 7.8GHz power extractor with a circular DL waveguide and tested it with single ...

Energy Technology Data Exchange (ETDEWEB)

The BNL Neutral Beam Development Group has been active in the program for the development of high energy, high power neutral beam systems since 1973. These injectors are based on the production, acceleration and neutralization of negative hydrogen or deuterium ions and are supposed to be used for plasma heating and current drive in the next generation of fusion devices. Over the span of 10 years the group has studied plasma-surface type of negative hydrogen ion sources, transport and acceleration of negative ion beams and neutralization of negative ions in gases and plasmas. As the required source parameters (current, pulse length, efficiency) were changing over this period of time, the group developed several types of sources, resulting finally in the design of a steady state device operating with an excellent gas efficiency and having the possibility of scaling-up to the size necessary for a high power neutral beam ...

International Nuclear Information System (INIS)

The possibility of developing reactor designs with inherent safety characteristics sufficient to provide ''walk away'' safety is receiving additional emphasis in the LMR program. A key element in this effort is the recognition that LMR's possess safety characteristics above and beyond those employed in past safety review processes. Some of these additional safety characteristics are due to reactivity feedback effects caused by small structural movements during hypothetical severe design transients. The effect of these characteristics upon the behavior of the FFTF under such transients has been assessed and is discussed in this paper. The paper also presents a preliminary test matrix which might allow experimental verification of the structural reactivity feedback effects. Such experimental verification should be very useful to innovative designers seeking to optimize inherent safety. 8 refs., 1 fig., 2 tabs.

CERN Document Server

We consider the effect of distributed delays in neural feedback systems. The avian optic tectum is reciprocally connected with the nucleus isthmi. Extracellular stimulation combined with intracellular recordings reveal a range of signal delays from 4 to 9 ms between isthmotectal elements. This observation together with prior mathematical analysis concerning the influence of a delay distribution on system dynamics raises the question whether a broad delay distribution can impact the dynamics of neural feedback loops. For a system of reciprocally connected model neurons, we found that distributed delays enhance system stability in the following sense. With increased distribution of delays, the system converges faster to a fixed point and converges slower toward a limit cycle. Further, the introduction of distributed delays leads to an increased range of the average delay value for which the system's equilibrium point is stable. The enhancement of ...

Energy Technology Data Exchange (ETDEWEB)

The insulating oil used in a transformer is a critical component, as its service life is typically 20 years with possibly little or no maintenance. Partial discharges (PD), thermal overloads and static discharges continually subject the oil to chemical deterioration during its operating life. To ensure equipment reliability during service, it is important that the initial quality of the new insulating oil should meet the required acceptance specifications and preferably be pre-tested before use. Accelerated aging tests have been devised to determine the life expectancy of oil in service by using forced air or oxygen flow into the oil, the presence of a copper catalyst, and at elevated temperatures. The more important standards relating to transformer application are discussed and highlights of the more important aspects of the oxidation chemistry of hydrocarbons are included. The ultimate aim of the project is the formulation of better standard ...

Energy Technology Data Exchange (ETDEWEB)

Large capacity adjustable speed machines (ASMs) at pumped storage power station have been put into full operation and the operating characteristics of ASM have been highly evaluated from the view point of power system operation. The output power (input power) of ASM can be controlled very quickly by applying a vector control scheme to the excitation control. This quick responsive feature of ASM can make it possible to improve the stability of the neighbor sub-power system. For improvement of transient stability, the output power of ASM is reduced very quickly in order to control the acceleration of neighbor generators during and after transmission line faults. For improvement of dynamic stability, the output power of ASM is modulated in accordance with the stabilizing signals detected from the swing of generator rotor or the power flow fluctuation on the transmission line. This paper describes the ...

Energy Technology Data Exchange (ETDEWEB)

One of the issues identified in the US Nuclear Regulatory Commission`s Nuclear Plant Aging Research program plan is the need to understand the state of ``mothballed`` or other out-of-service equipment to ensure subsequent safe operation. Programs for proper storage and preservation of materials and components are required by NRC regulations (10 CFR 50, Appendix B). However, materials and components have been seriously degraded due to improper storage, protection, or layup, at facilities under construction as well as those with operating licenses. Pacific Northwest Laboratory has evaluated management of aging for unstarted or mothballed nuclear power plants. The investigations revealed that no uniform guidance in the industry addresses reactor layup. In each case investigated, layup was not initiated in a timely manner, primarily because of schedule uncertainty. Hence, it is reasonable to assume that this delay resulted in ...

UK PubMed Central (United Kingdom)

SummaryBrown fat is specialized in energy expenditure, a process that is principally controlled by the transcriptional co-activator PGC-1α. Here we describe a molecular...Full Text Available

UK PubMed Central (United Kingdom)

Feedback controls of estrogen in LHRH-1 neurons play a pivotal role in reproductive function. However, the mechanism of estrogen action in LHRH-1 neurons is still unclear. In the present study, the...Full Text Available

UK PubMed Central (United Kingdom)

Acylation stimulating protein (ASP, C3adesArg) is an adipose tissue derived hormone that stimulates triglyceride (TG) synthesis. ASP stimulates lipoprotein lipase (LPL) activity by relieving feedback...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundSurveillance data allow for analysis, providing public health officials and policy-makers with a basis for long-term priorities and timely information on possible outbreaks...Full Text Available

UK PubMed Central (United Kingdom)

Normal reproductive functioning may require secretion of LH independently of FSH. Variation in GnRH pulse frequency and inhibin negative feedback are mechanisms for differential gonadotropin regulation;...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The information gathered as operating manager when implementing the first photovoltaic rural electrification and technology transfer program carried out to date in the world in French Polynesia from 1978 to 1990 are detailed. The technical developments of equipment and the work in progress at the GENEC Cadarache within French, European or IEA programs in order to improve some components or appliances and make up for certain deficiencies are presented. This involves accelerated aging tests, Standardization work, development of high efficiency equipment. Non technical barriers are often emphasized. Technical barriers also exists. Considerable work in many domains of small PV systems remains to be done so as to combine all the conditions required to implement successful large programs in developed as well as in developing countries.

Energy Technology Data Exchange (ETDEWEB)

The radiation control carried out in Atomic Energy Research Institute, Kinki University, for the reactor installation and the tracer/accelerator facilities from April, 1981, to March, 1982, is described. The reactor was operated for total 1057.1 hours at the maximum heat output of 1 W. The persons subject to radiation protection as of April, 1981, were 126 persons in all, including 23 in radiation work and 11 in X-ray work, etc. The contents of this report are as follows: personnel monitoring (health examination, the control of individual exposure dose); laboratory monitoring (the measurement of area dose rate, radioactive concentration in air and water, and surface contamination density); field monitoring (environmental ..gamma..-ray dose rate, radioactive concentration in environmental samples); the use of unsealed radioisotopes, etc.

Energy Technology Data Exchange (ETDEWEB)

In an ignition timing control apparatus for controlling the ignition timing of each cylinder in order to reduce knock generation in a multi-cylinder engine, a lag-angle correction is made for the ignition timing of a cylinder in which a knock is generated and at the same time, a slight lag-angle correction is made for the ignition timing of the other cylinders in which no knock is generated. When the operating condition of engine is rapidly changed for example, under the condition in which knock is liable to occur in all cylinders as at rapid acceleration time, a lag-angle correction is made by the same amount as in the knock generating cylinder, for the ignition timing of cylinders in which no knock is generated. When no knock is generated for a predetermined time, a lead-angle correction is made for the ignition timing subjected to the lag-angle correction of each cylinder at intervals of the predetermined time.

Energy Technology Data Exchange (ETDEWEB)

An apparatus for non-invasively inspecting an object, such as an item of luggage, for explosives material is described. It comprises a multi-channel thermal neutron inspection system having a plurality of neutron irradiation chambers. Simultaneous operation of several channels increases the maximum system throughput several times. Each chamber has a lithium neutron source which is stimulated to neutron production by a proton beam. Beam switching magnets are energised by pulsing to divert a common proton beam to each source in turn. The initial beam is generated by a radio frequency quadrupole accelerator. The advantages of this system are very low residual source activity and controllable neutron production thereby minimising safety hazards. The irradiation chamber may contain several different gamma ray detectors to identify the elements present in explosives material. In addition, a neutron radiography imaging means may be employed to ...

Energy Technology Data Exchange (ETDEWEB)

A number of difficult technical challenges need to be solved in the fields of accelerator and free-electron laser (FEL) technologies in order to build an X-ray FEL. One of the tasks well suited to the Advanced Photon Source Low Energy Undulator Test Line (LEUTL) is to take the intermediate step of solving some of the problems of single-pass FEL operation in the ultraviolet range. The existing Advanced Photon Source (APS) linac, in addition to its role of supply positrons for the APS storage ring, will also be used to generate the particle beam for the LEUTL. Here, the design of the magnetic system for the high gain soft x-ray free electron laser is described.

Energy Technology Data Exchange (ETDEWEB)

Composting is once again gaining interest among ecological engineers in view of greener industrial and residential activities. Uniform composting is needed to ensure decomposition and to keep the whole system at the same composting stage. A homogeneous temperature must be maintained throughout the media. A bioreactor design consisting of a heater core made of copper tubing was designed and tested. Two four-inch holes were made at the top and bottom of the barrel to allow air to flow through the system and promote aerobic composting. Once composting began and temperature increased, the water began to flow through the copper piping and the core heat was distributed throughout the medium. Three thermocouples were inserted at different heights on a 200 litre plastic barrel fitted with the aforementioned apparatus. Temperature variations were found to be considerably lower when the apparatus was operated with the heat redistribution system, enabling uniform composting, ...

Science.gov (United States)

This paper presents a systematic study on the stability of a two-dimensional vibration isolation floating raft system with a time-delayed feedback control. Based on the generalized Sturm criterion, the critical control gain for the delay-independent stability region and critical time delays for the stability switches are derived. The critical conditions can provide a theoretical guidance of chaotification design for line spectra reduction. Numerical simulations verify the correctness of the approach. Bifurcation analyses reveal that chaotification is more likely to occur in unstable region defined by these critical conditions, and the stiffness of the floating raft and mass ratio are the sensitive parameters to reduce critical control gain.

Energy Technology Data Exchange (ETDEWEB)

A systematic optimization method of choosing the weighting matrix in linear optimal control system design, under the conditions of prespecified closed-loop dominant eigenvalue locations and feedback gain limit constraints, is presented in this paper. Studies show that with the proposed method one can obtain the desired weighting matrix very quickly and conveniently without the heavy burden of choosing a suitable weighting matrix by trail and error. This method can also easily achieve a reduced-order feedback control system. The linear optimal power system stabilizer designed by using the proposed method produces very good performance.

Energy Technology Data Exchange (ETDEWEB)

The MTX explored the plasma heating effects of 140 GHz microwaves from both Gyrotrons and from the IMP FEL wiggler. The Gyrotron was long pulse length (0.5 seconds maximum) and the FEL produced short-pulse length, high-peak power, single and burst modes of 140 GHZ microwaves. Full-power operations of the IMP FEL wiggler were commenced in April of 1992 and continued into October of 1992. The Experimental Test Accelerator H (ETA-II) provided a 50-nanosecond, 6-MeV, 2--3 kAmp electron beam that was introduced co-linear into the IMP FEL with a 140 GHz Gyrotron master oscillator (MO). The FEL was able to amplify the MO signal from approximately 7 kW to peaks consistently in the range of 1--2 GW. This microwave pulse was transmitted into the MTX and allowed the exploration of the linear and non-linear effects of short pulse, intense power in the MTX plasma. Single pulses were used to explore and gain operating experience in the ...

UK PubMed Central (United Kingdom)

Based on the assumption that an accelerated proliferation process prevails in tumour cell residues after surgery, the possibility that treatment acceleration would offer a therapeutic advantage in postoperative...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Ion acceleration has now been demonstrated with the IFA-2 collective ion accelerator system. The IFA-2 system is described, photoionization experiments are summarized, and ion results are presented. Using a 1 MeV electron beam and a 30 cm acceleration length, IFA-2 has produced 5 MeV H/sup +/, 10 MeV D/sup +/, and 20 MeV He/sup + +/. This means that accelerating fields of 33 MV/m over 30 cm have been achieved with a controlled collective accelerator for the first time.

CERN Document Server

Background information on the high energy physics program and the proposed Stanford linear electron accelerator project

International Nuclear Information System (INIS)

... electron guns linear accelerators magnetrons multivibrators pulse generators

International Nuclear Information System (INIS)

In a closed circuit formed by bypassing pipelines connected to carbon steel parts, low oxygen coolants pass there through during operation. A solution containing ions of metals more noble than iron are circulated to bring the solution into contact with the carbon steel surface of the inner wall of the parts to form a deposition membrane of the metal more noble than iron on the surface to prevent acceleration of corrosion of the carbon steel parts due to low oxygen coolants. The solution containing ions of metals more noble than iron is a solution of palladium nitrate containing ions of platinum elements. This operation is conducted under a temperature condition of from 50degC to 150degC. In addition, the metal ion concentration of the solution circulating in the closed circuit is measured, it is compared with metal ion concentration previously determined, and the results are feed back to a means for controlling water ...

Energy Technology Data Exchange (ETDEWEB)

North Dakota Concrete Products Company uses a steam curing process that accelerates the concrete curing so that 28-day strength is obtained within 24 hours. The cost of energy required to accomplish this is significant, amounting to approximately $80,000 in 1980. The present boilers are oil fired. Recently, fuel oil prices have increased substantially. Further, supply shortages in the past have threatened plant production. The purpose of this study was to evaluate the economic feasibility of using deep formation warm water as an alternative energy source. A water-to-water heat pump system to replace the existing boiler system was investigated. TPI, Inc. economic and engineering findings for this particular potential geothermal application are disclosed. The operating cost savings of the geothermal system over the operating costs of the existing oilfired system would be insufficient to provide an acceptable rate of return on ...

Energy Technology Data Exchange (ETDEWEB)

A natural gas and diesel dual-fuel turbocharged compression ignition (CI) engine is developed to reduce emissions of a heavy-duty diesel engine. The compressed natural gas (CNG) pressure regulator is specially designed to feed back the boost pressure to simplify the fuel metering system. The natural gas bypass improves the engine response to acceleration. The modes of diesel injection are set according to the engine operating conditions. The application of honeycomb mixers changes the flowrate shape of natural gas and reduces hydrocarbon (HC) emission under low-load and lowspeed conditions. The cylinder pressures of a CI engine fuelled with diesel and dual fuel are analysed. The introduction of natural gas makes the ignition delay change with engine load. Under the same operating conditions, the emissions of smoke and NO{sub x} from the dual-fuel engine are both reduced. The HC and CO emissions for the dual-fuel engine ...

Energy Technology Data Exchange (ETDEWEB)

The necessary conditions to design the methanol-fueled direct injection diesel engine with a reservoir type glow plug were cleared up from the points of view to prevent the air contamination and to use as an alternative oil for automotives, and as a result the good engine performance and emission characteristics could be obtained under the wide operating condition. The following facts were clarified: It is necessary to arrange the glow plug on the line of atomizing axis near the nozzle hole to ensure the ignitability under a wide operating condition. The reservoir type glow plug which reserves the premixed gas around the glow plug can shorten the ignition delay time and improve the combustion stability and the net thermal efficiency in the light load region. The combustion in the light load region was accelerated, NO{sub x} emission rate was suppressed and moreover, the net thermal efficiency and catalyst conversion rate ...

International Nuclear Information System (INIS)

A two module electron beam source operating over a wide range of output parameters has been designed and fabricated to be used in conjunction with a pair of electron beam sustained CO_2 lasers. Each module comprised a grid-controlled thermionic electron beam gun including a compact grid pulser for control of the electron beam, a 250 kV thyratron switched modulator for acceleration of the electron beam, a 1 kHz filament heater and a complex computerized control system. The system was designed to reliably produce 45 #mu#s wide electron pulses of 150-200 keV energy, operate at repetition rates of 1-10 pps and current densities of 5-20 mA/cm"2. Additional parameters are listed. The high voltage cathode assembly employs 132 thoriated tungsten filaments distributed over the area of the 250 cm x 10 cm output window. The cathode assembly including the control grids is supported by two high voltage ceramic bushings in a stainless ...

Energy Technology Data Exchange (ETDEWEB)

After periodic testing of a large-scale spray calciner/ceramic melter vitrification system over a 2-yr period, sufficient corrosion was noted on various parts of the vitrification system to warrant its disassembly and inspection. A majority of the 316 SS sintered metal filters on the spray calciner were damaged by chemical corrosion and/or high temperature oxidation. Inconel-601 portions of the melter lid were attacked by chlorides and sulfates which volatilized from the molten glass. The refractory blocks, making up the walls of the melter, were attacked by the waste glass. This attack was occurring when operating temperatures were >1200/sup 0/C. The melter floor was protected by a sludge layer and showed no corrosion. Corrosion to the Inconel-690 electrodes was minimal, and no corrosion was noted in the offgas treatment system downstream of the sintered metal filters. It is believed that most of the melter corrosion occurred during one specific ...

Energy Technology Data Exchange (ETDEWEB)

We review the status of free electron laser (FEL) research being conducted at LBL and LLNL as part of a broader program of research on two beam accelerators (TBAs). Induction accelerator-driven FELs for use as power sources for high-gradient accelerators are discussed, along with preliminary cost estimates for this type of power source. Finally, a promising new version of an FEL/TBA is described. 25 refs., 1 fig., 3 tabs.

Science.gov (United States)

... in ATCM Recommendation XIV-2. The USAP's materials and waste management efforts are consistent with ...

Wastenet

aged gracefully: premature and accelerated corro - sion, erosion, and stress are raising maintenance costs.Last

Science.gov (United States)

One of the more-serious side effects of extended space flight is an accelerated bone loss

Science.gov (United States)

Linearly polarized laser radiation accelerates electrons to very high velocities and these electron form a sheath layer on the rear side of thin targets where preferentially protons are accelerated. When mass-limited targets are used, the lateral transport of the absorbed laser energy is reduced and the accelerating field is enhanced. For targets consisting of two ion species, heavier ions facilitate formation of quasi-monoenergetic bunch of lighter ions. For circularly polarized light, fast electron production is suppressed by the absence of the oscillatory component of the ponderomotive force. Ions are accelerated on the front side by the separation field and very thin foil can be accelerated as one massive quasi-neutral block. As all ion species acquire the same velocity, this acceleration mechanism is preferred for heavier ions.

International Nuclear Information System (INIS)

A study trip to a biomass gasification plant in Germany took place from 13-15 November 2000. The goal of the trip was to obtain information on German developments, experience, and possibilities in the field of biomass gasification. The participants were representatives of Dutch parties in the energy sector: waste sector, manufacturers, producers, policy makers and consultants. The most important feature was the visit to plants that were in operation. Due in particular to the new EEG (Emeuerbare-Energien-Gesetz/Renewable Energy) legislation, German policy makers have created an initial market for sustainable energy with a degree of success. The key feature is that EEG makes projects 'bankable' by guaranteeing a return delivery compensation. An EEG-type scheme designed to accelerate the development of sustainable energy could be an interesting instrument also for the Netherlands. The plan was to visit four plants and have a number of ...

International Nuclear Information System (INIS)

A microwave hydrogen ion source was developed to improve reliability, and to increase operation time of proton linac application systems. The ion source needs no filament in the discharge chamber, which leads to better reliability and less maintenance time. The developed source produced a maximum hydrogen ion beam current of 70 mA (high current density of 360 mA/cm2, beam energy of 30 keV) with a 5 mm diam extraction aperture and 1.2 kW microwave power. The proton fraction was increased with an increase in rf power and reached around 90% at 1 kW. Measured 90% beam normalized emittance was 0.4 #pi# mm mrad. Rise times of rf power and beam current to 90% of the final values were about 30 and 35 #mu#s, respectively, at a pulse operation mode with 400 #mu#s pulse width and 100 Hz repetition rate. The dynamic range of beam currents was enlarged (3-63 mA) in the pulse mode with a modified rf wave form to assist ignition of microwave discharge. These ...

International Nuclear Information System (INIS)

The current status of research and development in the realm of physics and technology of collective ion acceleration in systems with a virtual cathode (VC) is reviewed. Three major acceleration methods and devices developed on their basis are considered: reflex triodes and their modifications, gas-filled vircators, and vacuum vircators with a Luce diode. Experimental data are outlined and the principal physical models interpreting these data are described. New ion acceleration techniques whose realization involves the production and disappearance of the VC are also discussed. All methods of collective ion acceleration are compared and the possible ways for the further development of this promising scientific field are highlighted. (reviews of topical problems)

International Nuclear Information System (INIS)

Flow Accelerated Corrosion (FAC) of Carbon Steel (CS) piping has been one of main issues in Light-Water Nuclear Reactor (LWRs). Wall thinning of CS piping due to FAC increases potential risk of pipe rupture and cost for inspection and replacement of damaged pipes. In particular, corrosion products generated by FAC of CS piping brought steam generator (SG) tube corrosion and degradation of thermal performance, when it intruded and accumulated in secondary side of PWR. To preserve SG integrity by suppressing the corrosion of CS, High-AVT chemistry (Feedwater pH9.8#+-#0.2) has been adopted to Tsuruga-2 (1160 MWe PWR, commercial operation in 1987) in July 2005 instead of conventional Low-AVT chemistry (Feedwater pH 9.3). By the High-AVT adoption, the accumulation rate of iron in SG was reduced to one-quarter of that under conventional Low-AVT. As a result, a tendency to degradation of the SG thermal efficiency was improved. On the other hand, it ...

Energy Technology Data Exchange (ETDEWEB)

A decentralized power system stabilizer output feedback design approach is considered, which is compatible with expanding the construction of multi-machine systems. We presume that the interconnected power system is constructed by connecting closed-loop subsystems one after another. We take the proper stable factorization approach for calculating the local compensators. We apply the result to the new subsystem at each connection stage with unfixed power system stabilizer parameters. We then determine the parameters appropriately, before connection, so that the expanded system is stable after connection. A numerical example is worked out to illustrate the proposed design technique. 14 refs, 5 figs, 3 tabs

British Library Electronic Table of Contents (United Kingdom)

In this paper, a robust water level control system for the horizontal steam generator (SG) using the quantitative feedback theory (QFT) method is presented. To design a robust QFT controller for the nonlinear uncertain SG, control oriented linear models are identified. Then, the nonlinear system is modeled as an uncertain linear time invariant (LTI) system. The robust designed controller is applied to the nonlinear plant model. This nonlinear model is based on a locally linear neuro-fuzzy (LLNF) model. This model is trained using the locally linear model tree (LOLIMOT) algorithm. Finally, simulation results are employed to show the effectiveness of the designed QFT level controller. It is shown that it will ensure the entire designer's water level closed loop specifications.

CERN Document Server

The Elman artificial neural network (ANN) (feedback connection) was used for seismic data filtering. The recurrent connection that characterizes this network offers the advantage of storing values from the previous time step to be used in the current time step. The proposed structure has the advantage of training simplicity by a back-propagation algorithm (steepest descent). Several trials were addressed on synthetic (with 10% and 50% of random and Gaussian noise) and real seismic data using respectively 10 to 30 neurons and a minimum of 60 neurons in the hidden layer. Both an iteration number up to 4000 and arrest criteria were used to obtain satisfactory performances. Application of such networks on real data shows that the filtered seismic section was efficient. Adequate cross-validation test is done to ensure the performance of network on new data sets.

Energy Technology Data Exchange (ETDEWEB)

Maximum metal loss rate of Alloy 800 coupons was about 0.5 mil/year and occurred at the maximum temperature of 600/sup 0/C. Significantly greater oxide penetration into the alloy occurred in unabraded as-received tubing. Since the corrosion rate of unabraded tubing was less temperature sensitive than polished coupons, and attained a maximum value at temperatures in the range of 550 to 565/sup 0/C, a value of 1 mil/year should be used as the corrosion rate for design purposes. Because daily thermal cycling is inherent in solar central receiver operation, oxidation and chromium depletion rates can be expected to increase if surface oxide layers spall. The oxide layers formed on Alloy 800 appeared to be adherent, and adherence will benefit further from growth-derived compressive stresses in oxide layers on the salt-exposed inner diameter of receiver tubes. Since the lower duty factor in diurnal solar service may offset the accelerated metal loss ...

Energy Technology Data Exchange (ETDEWEB)

A large negative ion source for JT-60U produces high current ion beam from a wide extraction area of 45 cm x 110 cm. On the other hand, a cross-sectional area of the negative ion based neutral beam (NNB) injection port on JT-60U is narrow, about 50 cm x 60 cm. In order to inject the neutral beam at a high geometric efficiency, i.e. to suppress beam loss in the beamline, it is necessary to steer the beam for both compensation of undesirable beam deflection in extractor and focusing of the beam. For the JT-60U, two methods are provided for the required beam steering. Among them the results of beam steering experiment by aperture displacement and the design study are summarized in the present report. The experiment was carried out with 400 keV negative ion source, which has the three stage accelerator of similar structure as the JT-60U ion source, at Negative Ion Acceleration Test Stand (NIAS). High energy negative ion beams of the same perveance ...

International Nuclear Information System (INIS)

In 1980 the multilevel multichannel R-matrix code SAMMY was released for use in analysis of neutron data at the Oak Ridge Electron Linear Accelerator. Since that time, SAMMY has undergone significant modifications: (1) User-friendly options have been incorporated to streamline common operations and to protect a run from common user errors, (2) The Reich-Moore formalism has been extended to include an optional logarithmic parameterization of the external R-matrix, for which any or all parameters may be varied, (3) the ability to vary sample thickness, effective temperature, matching radius, and/or resolution-broadening parameters has been incorporated, (4) to avoid loss of information (i.e. computer round-off errors) between runs, the ''covariance file'' now includes precise values for al variables, (5) Unused but correlated variables may be included in the analysis. Because of these and earlier changes, the 1980 SAMMY manual is now hopelessly ...

International Nuclear Information System (INIS)

The 6911 m long Super Proton Synchrotron (SPS) at CERN with a peak energy of 450 GeV is at the top of the LHC preaccelerator-complex. Apart from the LHC, the SPS is with the Tevatron the accelerator with the largest stored beam energy of up to 2.5 MJ. The SPS has a known vulnerability to fast equipment failures that led to an uncontrolled loss of a high intensity beam in 2008, which resulted in major damage of a main dipole. The beam loss was caused by a fast tune decrease towards an integer resonance. Simulations and distinct experimental studies provide clear understanding of the beam dynamics at different SPS tune resonances. Diverging closed orbit oscillations, dispersion explosion and increased beta-beating are the driving effects that lead to a complete beam loss in as little as 10 turns (230 #mu#s) after reaching the stop band of the resonance. Dedicated experiments of fast failures of the main power converters reveal that the current interlock systems with ...

International Nuclear Information System (INIS)

Assessments of the hardening and embrittlement of pressure vessel steels and welds as a function of neutron dose use trend curves derived from surveillance programs and accelerated irradiation data. A temperature dependent factor is incorporated for assessing vessel locations operating at different temperatures. As hardening and embrittlement arise from the sum of matrix damage and copper impurity precipitation, the influence of irradiation temperature on each process needs to be established. For irradiations performed below #approx# 300 C recent data shows that the dose-dependent growth of copper precipitates ceases at a mean diameter of about 2 nm that also corresponds to peak hardening and embrittlement by copper. For doses beyond this peak copper dose the property-dependence on irradiation temperature can be identified with that of matrix damage alone. An analysis of several experiments on plate steels, performed at differing irradiation ...

Energy Technology Data Exchange (ETDEWEB)

A shock wave appears when the release of accumulated energy is instantaneous. For instance, it accompanies gunpowder explosion, electric discharge, laser beam convergence, collision of high-speed objects, release of high-pressure gas, and supersonic flight. The shock wave research center of Institute of Fluid Science, Tohoku University, is engaged in researches to elucidate the basics of various shock wave phenomena and to apply the fruit to engineering, science, and medicine. In this report, some examples of recent application studies at the center are described, and the trend of shock wave researches in the future is introduced. The ultimate state of the stagnation point of a nozzle flow simulating a reentry into the atmosphere is produced by shock wave compression in a free piston shock tube which is a ground-borne experimental apparatus. Los Alamos National Laboratory, U.S., succeeded in generating metallic hydrogen of a crystalline structure by subjecting liquid hydrogen to shock ...

Energy Technology Data Exchange (ETDEWEB)

The production methods for seven radioisotopes, Ga-67, Sr-85, Pd-103, In-111, Tm-167, Hg-197 and Pb-203, by using a classical 1.5m cyclotron in the Institute of Physics and Power Engineering, Obninsk, USSR, are described. At present, more than 50 cyclotrons in different countries are used for the production of radioisotopes applied to medicine. Radioisotopes are produced with the cyclotron in the I.Ph.P.E. in the form of irradiated targets, which are delivered to Moscow radiopharmaceutical factory, where radiopharmaceuticals are produced on the base of these targets. The cyclotron is operated in two regimes providing the acceleration of protons, deuterons and alpha -particles. Two types of target assemblies are used for irradiation, the one is intended for the internal beam, and the other is for the external beam. The reactions used for the production of seven radioisotopes described above, the types of targets, particle energy, respective ...

Energy Technology Data Exchange (ETDEWEB)

The ability to monitor the corrosion degradation of key components in fossil fuel power plants is of utmost importance for Futuregen and ultra-supercritical power plants. Fireside corrosion occurs in the high temperature sections of energy production facilities due to a number of factors: ash deposition, coal composition, thermal gradients, and low NOx conditions, among others. Problems occur when equipment designed for either oxidizing or reducing conditions is exposed to alternating oxidizing and reducing conditions. This can happen especially near the burners. The use of low NOx burners is becoming more commonplace and can produce reducing environments that accelerate corrosion. One method of addressing corrosion of these surfaces is the use of corrosion probes to monitor when process changes cause corrosive conditions. In such a case, corrosion rate could become a process control variable that directs the operation of a coal combustion or ...

Energy Technology Data Exchange (ETDEWEB)

A cohort of singleton black human females exposed to diagnostic x-ray in utero and controls matched by parity, hospital of birth and birthdate have been followed to ages 25 to 30 years in Baltimore, Maryland. The search for possible effects of prenatal irradiation has focused on health, growth, development, and reproductive experience of exposed and control women. This paper reports findings related to reproductive experience. From an original data set of 1458 matched exposed-control pairs of women, questionnaire responses were received from 1109 exposed and 1124 control women including 852 each from pairs in which both the exposed and control woman responded. After careful search for alternative explanations of the findings, the authors concluded that females exposed in utero to low doses of x-ray (probably 1 to 5 rads) had significant increases in their rates of early onset of menses, births at age 15 years or less, numbers of living children, stillbirths, and sterilizing ...

International Nuclear Information System (INIS)

LOCA (Loss of coolant accident) resistant heat-shrinkable polymeric products are widely used for the connection of LV cables for class 1E systems inside the containment area of nuclear power plants. The paper/presentation describes the verification of a reformulated compound for these products, where certain components of the compound formulation had to be substituted. A qualification programme with this so-called reformulated compound was undertaken to proof the equivalency of the products to the products made out of the original compound. The basic elements of this requalification project were material qualification tests including accelerated aging tests according to the arrhenius method and type tests in accordance to IEEE 383, including flammability tests. The test results showed that the products made out of the reformulated compound were similar in fit, form and function to the original products. Additional tests have also proven higher application ranges ...

CERN Document Server

Modified gravity theories may provide an alternative to dark energy to explain cosmic acceleration. We argue that the observational program developed to test dark energy needs to be augmented to capture new tests of gravity on astrophysical scales. Several distinct signatures of gravity theories exist outside the linear regime, especially owing to the screening mechanism that operates inside halos like the Milky Way to ensure that gravity tests in the solar system are satisfied. This opens up several decades in length scale and new classes of galaxies at low-redshift that can be exploited by surveys. While theoretical work on models of gravity is in the early stages, we can already identify new regimes which cosmological surveys could target to test gravity. These include: 1. A small scale component that focuses on the interior and vicinity of galaxy and cluster halos. 2. Spectroscopy of low redshift galaxies, especially galaxies smaller than ...

Energy Technology Data Exchange (ETDEWEB)

Relativistic electron beams are used for generating high power microwaves. These microwave sources require electron beam generators spanning significant ranges in voltage and impedance. The pulsed power technology used to generate these electron beams is presented. Electron beam generators that produce beams with pulse durations in the 10 ns to 100 ns regime consist of an energy storage section, pulse shaping section, and an electron beam diode. The energy storage section is either a Marx generator or capacitor bank-pulsed transformer. The pulse shaping is done with high-voltage transmission lines. The electron beam diode is usually a cold-cathode, space-charge-limited flow device. For longer pulses (approx.1 ..mu..s) the energy storage and pulse shaping can be combined. Lumped-element pulsed-forming networks (PFN) can be designed to produce the desired pulse shape. The Marx generator becomes one of the elements of the PFN. Alternatively, a low voltage PFN followed by a highly coupled ...

Energy Technology Data Exchange (ETDEWEB)

Candidate materials for components of a fluidized-bed waste heat recovery system (FBWHRS) include plain carbon steel, types 405 and 316 stainless steel, and alloy 800. These materials were exposed to synthetic flue gas at anticipated FBWHRS temperatures and higher for 3000 h to determine corrosion rates. The synthetic flue gas was a combustion atmosphere to which Cl/sub 2/ and HCl were added. The projected annual corrosion rate for plain carbon steel is about 0.08 mm/year (0.003 in./year) at 250 to 290/sup 0/C, but it would exceed 0.5 mm/year (0.02 in./year) at 560/sup 0/C. The projected annual corrosion rates of the other materials were less than 0.25 mm/year (0.01 in./year) at the maximum test temperatures of 560, 660, and 665/sup 0/C for type 405, type 316, and alloy 800, respectively. These results indicate that corrosion of candidate FBWHRS materials will not be significant at anticipated operating temperatures for various components unless other factors, not ...

Energy Technology Data Exchange (ETDEWEB)

This publication provides a broad overview of the research programs and efforts being conducted, built, designed, and planned at Brookhaven National Laboratory. This work covers a broad range of scientific disciplines. Major facilities include the Alternating Gradient Synchrotron (AGS), with its newly completed booster, the National Synchrotron Light Source (NSLS), the High Flux Beam Reactor (HFBR), and the RHIC, which is under construction. Departments within the laboratory include the AGS department, accelerator development, physics, chemistry, biology, NSLS, medical, nuclear energy, and interdepartmental research efforts. Research ranges from the pure sciences, in nuclear physics and high energy physics as one example, to environmental work in applied science to study climatic effects, from efforts in biology which are a component of the human genome project to the study, production, and characterization of new materials. The paper provides an overview of the ...

Energy Technology Data Exchange (ETDEWEB)

A concept is shown for a fully reusable, Earth-to-orbit launch vehicle with horizontal takeoff and landing, employing an air-turborocket for low speed and a rocket for high-speed acceleration, both using liquid hydrogen for fuel. The turborocket employs a modified liquid air cycle to supply the oxidizer. The rocket uses 90% pure liquid oxygen as its oxidizer that is collected from the atmosphere, separated, and stored during operation of the turborocket from about Mach 2 to 5 or 6. The takeoff weight and the thrust required at takeoff are markedly reduced by collecting the rocket oxidizer in-flight. This article shows an approach and the corresponding technology needs for using air liquefaction and enrichment system propulsion in a single-stage-to-orbit (SSTO) vehicle. Reducing the trajectory altitude at the end of collection reduces the wing area and increases payload. The use of state-of-the-art materials, such as graphite polyimide, in a ...

Energy Technology Data Exchange (ETDEWEB)

A novel scheme is proposed to drive a low-power subcritical fuel assembly by means of a long Cylindrical Radially-convergent Inertial Electrostatic Confinement (CRIEC) used as a neutron source. The concept is inherently safe in the sense that the fuel assembly remains subcritical at all times. Previous work has been done for the possible implementation of CRIEC as a subcritical assembly driver for power reactors. However, it has been found that the present technology and stage of development of IEC-based neutron sources can not meet the neutron flux requirements to drive a system as big as a power reactor. Nevertheless, smaller systems, such as research and training reactors, could be successfully driven with levels of neutron flux that seem more reasonable to be achieved in the near future by IEC devices. The need for custom-made expensive nuclear fission fuel, as in the case of the TRIGA reactors, is eliminated, and the CRIEC presents substantial advantages with respect to the ...

International Nuclear Information System (INIS)

The development and occurrence of new electron accelerators and applications are according to the human society development law, as a whole. The period of economic standstill is generating an intense creative activity in the domain of science and engineering which also resulting in great achievements in the field of electron accelerators. This paper presents the basic principle of the electron beam applications and the accelerators required characteristics for their present and potential applications in the domains: radiation sources, diagnostics, radiation processing, energetics, environment, defense and basic sciences. All these are correlated to the new generation of accelerators which, for the acceleration process, may employ electromagnetic fields generated by standard sources, atomic lasers, free electron lasers, Cerenkov effect, Smith - Purcell effect, electron beams, plasma, ...

International Nuclear Information System (INIS)

A scheme for on-line tuning of a fuzzy-logic power system stabilizer is presented. firstly, a fuzzy-logic power system stabilizer is developed using speed deviation and accelerating power as the controller input variables. The inference mechanism of fuzzy-logic controller is represented by a decision table, constructed of linguistic IF-THEN rules. The Linguistic rules are available from experts and the design procedure is based on these rules. It assumed that an exact model of the plant is not available and it is difficult to extract the exact parameters of the power plant. Thus, the design procedure can not be based on an exact model. This is an advantage of fuzzy logic that makes the design of a controller possible without knowing the exact model of the plant. Secondly, two scaling parameters are introduced to tune the fuzzy-logic power system stabilizer. These scaling parameters are the outputs of another fuzzy-logic system, which gets the ...

Energy Technology Data Exchange (ETDEWEB)

The Mittelplate oilfield is located in the Waddensea tidelands 8 km off the north sea coast and represents Germany's largest oilfield. Since Mittelplate oil production has started in 1987, RWE Dea AG being the operator in a 50/50 joint venture with Wintershall AG, has continually implemented and improved the sophisticated technology required to exploit natural resources by using safe and environmentally compatible means in the sensitive tideland environment of Mittelplate. Besides the sucessful offshore operations from the man-made Mittelplate Drilling and Production Island, further onshore development has started in 2000 by producing from high-tech ERD wells drilled from onshore locations. The offshore oil production had been transported so far by specially designed tug and tow barges and had been restricted by weather and tide. To overcome this bottleneck and to enable an accelerated offshore drilling and ...

Energy Technology Data Exchange (ETDEWEB)

GaAs-based dc high voltage photoguns used at accelerators with extensive user programs must exhibit long photocathode operating lifetime. Achieving this goal represents a significant challenge for proposed high average current facilities that must operate at tens of milliamperes or more. This paper describes techniques to maintain good vacuum while delivering beam, and techniques that minimize the ill effects of ion bombardment, the dominant mechanism that reduces photocathode yield of a GaAs-based dc high voltage photogun. Experimental results presented here demonstrate enhanced lifetime at high beam currents by: (a) operating with the drive laser beam positioned away from the electrostatic center of the photocathode, (b) limiting the photocathode active area to eliminate photoemission from regions of the photocathode that do not support efficient beam delivery, (c) using a large drive laser beam to ...

Wastenet

...Simplification of the scheme - Department of Energy and Climate Change simplification, crc energy efficiency scheme Simplification of the scheme Simplification of the CRC Energy ...Efficiency Scheme The Government is considering the simplification of the CRC in the light of experience since the scheme began in April 2010. ...will take into account feedback from stakeholders including: the effectiveness of the CRC framework for driving energy efficiency in large private and public sector ... The perceived complexity of the CRC scheme and hence the administrative burden on: - those organisations that are subject to ...

Wastenet

...notice de en es fr it nl European Commission Research Index aeronews All keywords Index feedback The number of documents that contain the keyword aeronews is: 1 EU Transport lsquo;AERONEWSrsquo; -good news for early detection of microdamage European Commission - lsquo;AERONEWSrsquo; -good news for early detection of microdamage ...

Energy Technology Data Exchange (ETDEWEB)

An optical voltage reference for providing an alternative to a battery source. The optical reference apparatus provides a temperature stable, high precision, isolated voltage reference through the use of optical isolation techniques to eliminate current and impedance coupling errors. Pulse rate frequency modulation is employed to eliminate errors in the optical transmission link while phase-lock feedback is employed to stabilize the frequency to voltage transfer function.

Science.gov (United States)

Background: Protein disulfide isomerase (PDI) controls platelet integrin function, tissue-factor (TF) activation, and concentrates at fibrin and thrombus formation sites of vascular injury. Objective: We investigated involvement of surface thiol isomerases and especially PDI, in thrombin-mediated thrombin amplification on human platelets. Methods/Results: Using a new developed thrombin-dependent platelet thrombin generation assay we observed that the feedback activation of thrombin generation on the platelet surface does not depend on TF, as anti-TF antibodies inhibiting TF-induced thrombin formation in platelet-depleted plasma had no effect compared to vehicle-treated controls. Feedback activation of thrombin generation in the presence of platelets was significantly diminished by membrane impermeant thiol blockers or by the thiol isomerase-inhibitors bacitracin and anti-PDI antibody RL90, respectively. Platelet thrombin formation depends on ...

CERN Multimedia

"American dominance in the study and development of high-energy particle physics may be seriously compromised, according to a report issued by the National Academy of Sciences, unless efforts are made to ensure that the next high-energy particle accelerator - the International Linear Collider (ILC) - will be constructed in the U.S.

UK PubMed Central (United Kingdom)

We describe the lethal, recessive accelerated-cell-death11 Arabidopsis mutant (acd11). Cell death in acd11 exhibits characteristics of animal apoptosis...Full Text Available

International Nuclear Information System (INIS)

A linear induction accelerator that produces a beam of energetic heavy ions (T #approx =# 10 GeV, A #approx =# 200 am#mu#) is a prime candidate as a driver for an inertial fusion power plant. Some early perceptions were that heavy-ion driven fusion would not be cost-competitive with other power sources because of the high cost of the accelerators. However, improved understanding of the physics of heavy-ion transport and acceleration (supported by experimental results), combined with advances in accelerator technology, have resulted in accelerator design costs -- 50% of previous estimates. As a result, heavy-ion driven fusion power plants conceptual fusion power plants. A brief formulation of transport and acceleration physics is presented here, along with a description of the induction Linac cost optimization code LIACEP. Cost trends are presented and discussed, ...

International Nuclear Information System (INIS)

A simple beam-forming system is described for the electrostatic accelerator of the Scientific-Research Institute of Nuclear Physics of Moscow State University. The system allows the beam to be focused on targets at various distances for a conductor potential of from 1 to 4 MV and beam currents of up to 35 #mu# A.

Science.gov (United States)

The major projects of the Los Alamos National Laboratory's Accelerator Technology Division are discussed, covering activities that occurred during the first six months of calendar 1982.

UK PubMed Central (United Kingdom)

OBJECTIVE: To increase cost-efficiency while maintaining the standard of medical care, an accelerated surgical stay program for patients having breast surgery was instituted. SUMMARY BACKGROUND DATA:...Full Text Available

International Nuclear Information System (INIS)

... beam monitoring betatrons delay circuits errors fluctuations gamma radiation

KoreaScience (Korea)

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International Nuclear Information System (INIS)

... Tsukuba, Ibaraki (Japan) 389 p. PARTICLE ACCELERATORS beam monitoring

International Nuclear Information System (INIS)

... aluminium 28 building materials cockcroft-walton accelerators copper copper

Energy Technology Data Exchange (ETDEWEB)

The SciDAC2 accelerator project at SLAC aims to simulate an entire three-cryomodule radio frequency (RF) unit of the International Linear Collider (ILC) main Linac. Petascale computing resources supported by advances in Applied Mathematics (AM) and Computer Science (CS) and INCITE Program are essential to enable such very large-scale electromagnetic accelerator simulations required by the ILC Global Design Effort. This poster presents the recent advances and achievements in the areas of CS/AM through collaborations.

Energy Technology Data Exchange (ETDEWEB)

A study trip to a biomass gasification plant in Germany took place from 13-15 November 2000. The goal of the trip was to obtain information on German developments, experience, and possibilities in the field of biomass gasification. The participants were representatives of Dutch parties in the energy sector: waste sector, manufacturers, producers, policy makers and consultants. The most important feature was the visit to plants that were in operation. Due in particular to the new EEG (Emeuerbare-Energien-Gesetz/Renewable Energy) legislation, German policy makers have created an initial market for sustainable energy with a degree of success. The key feature is that EEG makes projects 'bankable' by guaranteeing a return delivery compensation. An EEG-type scheme designed to accelerate the development of sustainable energy could be an interesting instrument also for the Netherlands. The plan was to visit four plants and have a ...

Energy Technology Data Exchange (ETDEWEB)

Following a referendum in Italy in 1987, the four Nuclear Power Plants (NPPs) owned and operated by the state utility ENEL were closed. After closing the NPPs, ENEL selected a ''safestore'' decommissioning strategy; anticipating a safestore period of some 40-50 years. This approach was consistent with the funds collected during plant operation, and was reinforced by the lack of both a waste repository and a set of national free release limits for contaminated materials in Italy. During 1999, twin decisions were made to privatize ENEL and to transform the nuclear division into a separate subsidiary of the ENEL group. This group was renamed Sogin and during the following year, ownership of the company was transferred to the Italian Treasury. On formation, Sogin was asked by the Italian government to review the national decommissioning strategy. The objective of the review was to move from a safestore strategy ...

Energy Technology Data Exchange (ETDEWEB)

Plans for the disposal of radioactive liquid and solid wastes presently stored in double-shell tanks at the Hanford Site call for retrieval and processing of the waste to create forms suitable for permanent disposal. Waste will be retrieved from a tank using a submerged slurry pump in conjunction with one or more rotating slurry jet mixer pumps. Pacific Northwest Laboratory (PNL) has conducted tests using simulated waste slurries to assess the effects of a impinging slurry jet on the corrosion rate of the tank wall and floor, an action that could potentially compromise the tank's structural integrity. Corrosion processes were investigated on a laboratory scale with a simulated neutralized cladding removal waste (NCRW) slurry and in a subsequent test with simulated neutralized current acid waste (NCAW) slurry. The test slurries simulated the actual NCRW and NCAW both chemically and physically. The tests simulated those conditions expected to exist in the respective double-shell ...

Energy Technology Data Exchange (ETDEWEB)

In the 14 MeV Neutron Laboratory, we have continued the development of a facility that is now the only one of its kind in operation in the United States. We have refined the klystron bunching system described in last year's report to the point that 1.2 nanosecond pulses have been directly measured. We have tested the pulse shape discrimination capability of our primary NE 213 neutron detector. We have converted the RF sweeper section of the beamline to a frequency of 1 MHz to replace the function of the high voltage pulser described in last year's report which proved to be difficult to maintain and unreliable in its operation. We have also overcome several other significant experimental difficulties, including a major problem with a vacuum leak in the main accelerator column. We have completed additional testing to prove the remainder of the generation and measurement systems, but overcoming some of these ...

J-STORE (Japan)

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Science.gov (United States)

We consider a unified model of Fe ion acceleration in the solar corona. The model comprises charge-changing processes, Coulomb energy losses, and both regular and stochastic acceleration. At a given acceleration scenario, the type of acceleration is found to have a minor effect on the mean charge states, but the shapes of the charge-state distributions produced by regular acceleration and by stochastic acceleration are different. During a continual acceleration at coronal temperatures, iron ions typically follow rising trajectories on the charge-energy plane. These trajectories are situated below the mean equilibrium charge curve defined from the balance of ionization and recombination at fixed energy. During stopping, the iron ions cross the equilibrium charge curve and run through a series of charge states above the mean equilibrium charge ...

International Nuclear Information System (INIS)

The compost bioreactor ('anaerobic cell') components of three composite passive remediation systems constructed to treat acid mine drainage (AMD) at the former Wheal Jane tin mine, Cornwall, UK were studied over a period of 16 months. While there was some amelioration of the preprocessed AMD in each of the three compost bioreactors, as evidenced by pH increase and decrease in metal concentrations, only one of the cells showed effective removal of the two dominant heavy metals (iron and zinc) present. With two of the compost bioreactors, concentrations of soluble (ferrous) iron draining the cells were significantly greater than those entering the reactors, indicating that there was net mobilisation (by reductive dissolution) of colloidal and/or solid-phase ferric iron compounds within the cells. Soluble sulfide was also detected in waters draining all three compost bioreactors which was rapidly oxidised, in contrast to ferrous iron. Oxidation and hydrolysis of iron, together with ...

CERN Document Server

We investigate the formation and evolution of dwarf galaxies in a high resolution, hydrodynamical cosmological simulation of a Milky Way sized halo and its environment. Our simulation includes gas cooling, star formation, supernova feedback, metal enrichment and UV heating. In total, 90 satellites and more than 400 isolated dwarf galaxies are formed in the simulation, allowing a systematic study of the internal and environmental processes that determine their evolution. We find that 95% of satellite galaxies are gas-free at z=0, and identify three mechanisms for gas loss: supernova feedback, tidal stripping, and photo-evaporation due to re-ionization. Gas-rich satellite galaxies are only found with total masses above ~ 5x10^9 solar masses. In contrast, for isolated dwarf galaxies, a total mass of ~ 10^9 solar masses constitutes a sharp transition; less massive galaxies are predominantly gas-free at z=0, more massive, isolated dwarf galaxies are ...

International Nuclear Information System (INIS)

The Moderator Temperature Coefficient of reactivity (MTC) was earlier proven to be properly determined via noise analysis when the neutron noise is measured locally and when the radial average of the moderator temperature noise is used. Nevertheless, measurements revealed that the MTC was correctly estimated on a much narrower frequency band (0.6 - 0.7 Hz) than expected (0.1 - 1.0 Hz). The present paper investigates the effect of the feedback on the MTC determination using this new MTC noise estimator (which could explain the deviation at low frequencies, i.e. between 0.1 - 0.5 Hz) and the effect of the detector time constants (which could explain the deviation at high frequencies, i.e. between 0.7 - 1.0 Hz). For that purpose, a coupled neutronic/thermalhydraulic model of the Ringhals-3 PWR is developed in the frequency-domain, based on a radial 2-dimensional heterogeneous representation of the core. The transfer function of the detectors is also modelled in this ...

CERN Document Server

We study quantized beamforming in wireless amplify-and-forward relay-interference networks with any number of transmitters, relays, and receivers. We design the quantizer of the channel state information to minimize the probability that at least one receiver incorrectly decodes its desired symbol(s). Correspondingly, we introduce a generalized diversity measure that encapsulates the conventional one as the first-order diversity. Additionally, it incorporates the second-order diversity, which is concerned with the transmitter power dependent logarithmic terms that appear in the error rate expression. First, we show that, regardless of the quantizer and the amount of feedback that is used, the relay-interference network suffers a second-order diversity loss compared to interference-free networks. Then, two different quantization schemes are studied: First, using a global quantizer, we show that a simple relay selection scheme can achieve maximal diversity. Then, ...

British Library Electronic Table of Contents (United Kingdom)

A metamaterial that is composed of solid viscoelastic elements with controllable properties is proposed in this Letter. This enables an adaptable and general acoustic metamaterial to be practically realised. An array of masses with a single elastic connection to a supporting viscoelastic structure, such as one that is dynamically equivalent to an array of Helmholtz resonators, only provides a system with negative effective mass. A local active control scheme applied to each of these masses can emulate additional elastic connections to the supporting structure. An array of masses with a suitable local control scheme can provide both the negative effective stiffness and mass required for negative refraction. The tuneable feedback control parameters determine the characteristics of the region...

International Nuclear Information System (INIS)

Field Programmable Gate Arrays (FPGAs) are being used in space applications because of attractive attributes: good density, moderate speed, low cost, and quick turn-around time. However, these devices are susceptible to Single Event Upsets (SEUs). An approach using triple modular redundancy (TMR) and feedback was developed for flip-flop hardening in these devices. Test data showed excellent results for this circuit topology. Total dose and Single Event Effect (SEE) testing have been performed on recently released technologies. Failures are analyzed and test methodology is discussed.

British Library Electronic Table of Contents (United Kingdom)

Recent research developments in common-pool resource models emphasize the importance of links with ecological systems and the presence of non-linearities, thresholds and multiple steady states. In a recent paper Kossioris et al. (2008) develop a methodology for deriving feedback Nash equilibria for non-linear differential games and apply this methodology to a common-pool resource model of a lake where pollution corresponds to benefits and at the same time affects the ecosystem services. This paper studies the structure of optimal state-dependent taxes that steer the combined economic-ecological system towards the trajectory of optimal management, and provides an algorithm for calculating such taxes.

CERN Document Server

We study diffusion of Cosmic Rays (CRs) in turbulent magnetic fields using test particle simulations. Electromagnetic fields are produced in direct numerical MHD simulations of turbulence and used as an input for particle tracing, particle feedback on turbulence being ignored. Statistical transport coefficients from the test particle runs are compared with earlier analytical predictions. We find qualitative correspondence between them in various aspects of CR diffusion. In the incompressible case, that we consider in this paper, the dominant scattering mechanism occurs to be the non-resonant mirror interactions with the slow-mode perturbations. Perpendicular transport roughly agrees with being produced by magnetic field wandering.

International Nuclear Information System (INIS)

The multi-frequency binary sequence experimental technique has been implemented at the Fast Flux Test Facility for routine surveillance activities. The frequency content of the standard rod-movement sequence has been shown to be sufficient to normalize the data at moderate frequencies. This obviates the need for auxiliary calibration measurements and provides the reactivity worth of the test control rod. Analyses of a series of tests conducted in 1986 illustrate that the rod worths inferred from the tests are consistent with zero-power measurements. Also, the dependence of the prompt feedback time constant on reactor conditions was determined.

British Library Electronic Table of Contents (United Kingdom)

Botulinum neurotoxin is produced by the bacterium, Clostridium botulinum. The neurotoxin inhibits acetylcholine at the neuromuscular junction, thus interfering with overall muscular contraction. Botulinum neurotoxin is commonly used for the following medical conditions: cervical dystonia, upper limb spasticity, blepharospasm, strabismus, and hyperhydrosis. However, the use of botulinum neurotoxin was recently approved for the prophylaxis of headaches in adults with chronic migraines. The proposed mechanism of botulinum neurotoxin is no longer solely limited to the inhibition of acetylcholine. There are new mechanisms emerging that involve inhibition of proinflammatory agents and neuropeptides involved in chronic pain. Consequently, there is a disruption of the overall sensory feedback loop...

Energy Technology Data Exchange (ETDEWEB)

Radiation-and-thermal-combined degradation of ethylene-propylene rubber (EP rubber) and chlorosulfonated polyethylene (CSM) as cable insulating and jacketing materials were evaluated by accelerated aging tests and a method to assess the lifetime of these materials under practical application was studied. EP rubber and CSM of experimental formulation were degraded at accelerated rates, that are 50 [approx] 1000 times the degradation rate under a standard condition (1Gy/h, 50degC). The degradation was investigated by measuring the tensile properties. In the accelerated aging tests, rates of elongation decrease owing to degradation for both EP rubber and CSM were in proportion to increase in accelerated rate. Behaviors of elongation changes showed little difference with accelerated rate. EP rubber lifetime estimated from sequential aging test had a tendency to extend beyond that from ...

Energy Technology Data Exchange (ETDEWEB)

A study was conducted under the auspices of the Coordinating Research Council, Inc. (CRC) to assess the potential effects of gasoline octane quality on vehicle acceleration performance. Twelve participating laboratories, representing both the oil and the automotive industries, tested a total of 182 vehicles as part of the 1989 CRC Octane Number Requirement Survey. The vehicles consisted of 78 with electronic knock control systems and 104 without. All testing was performed using the 1989/1990 CRC FBRU fuel series. The results showed that acceleration performance of vehicles with knock sensors was significantly affected by gasoline octane quality. Octane effects on acceleration performance were most pronounced at maximum-throttle (detent) conditions and at octane levels below the vehicles' octane requirements; however, some knock-sensor vehicles did show improved acceleration performance with ...

Energy Technology Data Exchange (ETDEWEB)

Analytical and numerical calculations are presented for a reflexing electron beam type of collective ion accelerator. These results are then compared to those obtained through experiment. By constraining one free parameter to experimental conditions, the self-similar solution of the ion energy distribution agrees closely with the experimental distribution. Hence the reflexing beam model appears to be a valid model for explaining the experimental data. Simulation shows in addition to the agreement with the experimental ion distribution that synchronization between accelerated ions and electric field is phase unstable. This instability seems to further restrict the maximum ion energy to several times the electron energy.

CERN Multimedia

"The US must develop a compelling bid to host the International Linear Collider in order to safeguard American science." (1,5 page)

Science.gov (United States)

We study a two-level atom in interaction with a real massless scalar quantum field in a spacetime with a reflecting boundary. The presence of the boundary modifies the quantum fluctuations of the scalar field, which in turn modifies the radiative properties of atoms. We calculate the rate of change of the mean atomic energy of the atom for both inertial motion and uniform acceleration. It is found that the modifications induced by the presence of a boundary make the spontaneous radiation rate of an excited inertial atom oscillate near the boundary and this oscillatory behavior may offer a possible opportunity for experimental tests for geometrical (boundary) effects in flat spacetime. While for accelerated atoms, the transitions from ground states to excited states are found to be possible even in a vacuum due to changes in the vacuum fluctuations induced by both the presence of the boundary and the acceleration of atoms, ...

UK PubMed Central (United Kingdom)

A report on the Wellcome Trust/Cold Spring Harbor Genome Informatics meeting, Cold Spring Harbor, USA, 7-11 May 2003.