Development of MicroMegas for a Digital Hadronic Calorimeter

OpenAIRE

Adloff, Catherine; Blaha, Jan; Espargiliere, Ambroise; Karyotakis, Yannis

2009-01-01

Recent developments on the MicroMegas prototypes built by use of the bulk technology with analog and digital readout electronics are presented. The main test beam results of a stack of several MicroMegas prototypes fully comply with the needs of a hadronic calorimeter for future particle physics experiments. A technical solution for a large scale prototype is also introduced.

THE CENTURY OF MEGA - DAGUOS. THE CHARTER OF PEACEFUL COEXISTENCE AMONG THE MEGA - DAGUOS

Directory of Open Access Journals (Sweden)

Mădălina Virginia ANTONESCU

2017-11-01

Full Text Available The current paper discusses the origins of the concept of “daguo”, a term used in the Chinese academic literature to refer to the “great powers”. We will use a particular concept, i.e. “mega -daguo”, to refer to entities higher than the great powers (states, in the classic sense, that is new, trans-state or super -state actors of transcontinental or continental dimensions. Such entities create fusions among different civilizations; they have a specific behaviour, distinct from the behaviour of great powers, as currently perceived by us, in the traditional sense of the term. The current paper analyses the typology of mega-daguos; we will refer to the post-Huntingtonian age, that of a world which has overcome the dualist paradigm of the “inevitable conflict” among the civilizations, a world which has turned the principle of dialogue among the mega-daguos into a fundamental principle underlying a world of colossi. The last part of the paper proposes a fundamental document of the new world of post-state actors (mega-daguos, for the 21st century. We will call it the“Charter of peaceful coexistence among the mega-daguos”, with an approach to the issue of reorganizing the UN, in order to be able to come to terms with such reality, in the 21stcentury post-state world based on a global law, in which post - state actors are also legally responsible for their behaviour and their decisions, at global level.

Effect of cAMP on short-circuit current in isolated human ciliary body.

Science.gov (United States)

Wu, Ren-yi; Ma, Ning; Hu, Qian-qian

2013-07-01

Cyclic adenosine monophosphate (cAMP) could activate chloride channels in bovine ciliary body and trigger an increase in the ionic current (short-circuit current, Isc) across the ciliary processes in pigs. The purpose of this study was to investigate how cAMP modulates Isc in isolated human ciliary processes and the possible involvement of chloride transport across the tissue in cAMP-induced Isc change. In an Ussing-type chamber system, the Isc changes induced by the cAMP analogue 8-bromo-cAMP and an adenylyl cyclase activator forskolin in isolated human ciliary processes were assessed. The involvement of Cl(-) component in the bath solution was investigated. The effect of Cl(-) channel (10 µmol/L niflumic acid and 1 mmol/L 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS)), K(+) channel (10 mmol/L tetraethylammonium chloride (TEA)), or Na(+) channel blockers (1 mmol/L amiloride) on 8-bromo-cAMP-induced Isc change was also studied. Dose-dependently, 8-bromo-cAMP (10 nmol/L-30 µmol/L) or forskolin (10 nmol/L-3 µmol/L) increased Isc across the ciliary processes with an increase in negative potential difference on the non-pigmented epithelium (NPE) side of the tissue. Isc increase induced by 8-bromo-cAMP was more pronounced when the drug was applied on the NPE side than on the pigmented epithelium side. When the tissue was bathed in low Cl(-) solutions, the Isc increase was significantly inhibited. Finally, niflumic acid and DIDS, but not TEA or amiloride, significantly prevented the Isc increase induced by 8-bromo-cAMP. cAMP stimulates stroma-to-aqueous anionic transport in isolated human ciliary processes. Chloride is likely to be among the ions, the transportation of which across the tissue is triggered by cAMP, suggesting the potential role of cAMP in the process of aqueous humor formation in human eyes.

The effect of off-axis neutral beam injection on sawtooth stability in ASDEX Upgrade and Mega-Ampere Spherical Tokamak

International Nuclear Information System (INIS)

Chapman, I. T.; de Bock, M. F.; Pinches, S. D.; Turnyanskiy, M. R.; Igochine, V. G.; Maraschek, M.; Tardini, G.

2009-01-01

Sawtooth behavior has been investigated in plasmas heated with off-axis neutral beam injection in ASDEX Upgrade [A. Herrmann and O. Gruber, Fusion Sci. Technol. 44, 569 (2003)] and the Mega-Ampere Spherical Tokamak (MAST) [A. Sykes et al., Nucl. Fusion 41, 1423 (2001)]. Provided that the fast ions are well confined, the sawtooth period is found to decrease as the neutral beam is injected further off-axis. Drift kinetic modeling of such discharges qualitatively shows that the passing fast ions born outside the q=1 rational surface can destabilize the n=1 internal kink mode, thought to be related to the sawtooth instability. This effect can be enhanced by optimizing the deposition of the off-axis beam energetic particle population with respect to the mode location.

LANSCE beam current limiter

International Nuclear Information System (INIS)

Gallegos, F.R.

1996-01-01

The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) provides personnel protection from prompt radiation due to accelerated beam. Active instrumentation, such as the Beam Current Limiter, is a component of the RSS. The current limiter is designed to limit the average current in a beam line below a specific level, thus minimizing the maximum current available for a beam spill accident. The beam current limiter is a self-contained, electrically isolated toroidal beam transformer which continuously monitors beam current. It is designed as fail-safe instrumentation. The design philosophy, hardware design, operation, and limitations of the device are described

A LVDT conditioner for the beam profile monitors of the AmPS

International Nuclear Information System (INIS)

Es, J.T. van; Trigt, J.H. van.

1991-01-01

A LVDT (Linear Variable Differential Transformer) is a transducer for localization. Because of its applied materials, its construction and the absence of bearings etc. the instrument is suitable to be applied in locations where radioactive radiation is present. In order to obtain information about the position of the iron core in the transducer, a conditioner is needed. In 1977 by Digel a conditioner has been developed for the beam profile monitors (moving wire) of MEA because the 'market' could not meet the requirements then. Nowadays the 'market' offers i.c.'s which can take over the work of the Eurocard developed then. Digel has investigated them in order to see if they are applicable for the beam profile monitors of AmPS. (author). 5 refs.; 7 figs.; 13 tabs

cAMP Stimulates Transepithelial Short-Circuit Current and Fluid Transport Across Porcine Ciliary Epithelium.

Science.gov (United States)

Cheng, Angela King-Wah; Civan, Mortimer M; To, Chi-Ho; Do, Chi-Wai

2016-12-01

To investigate the effects of cAMP on transepithelial electrical parameters and fluid transport across porcine ciliary epithelium. Transepithelial electrical parameters were determined by mounting freshly isolated porcine ciliary epithelium in a modified Ussing chamber. Similarly, fluid movement across intact ciliary body was measured with a custom-made fluid flow chamber. Addition of 1, 10, and 100 μM 8-Br-cAMP (cAMP) to the aqueous side (nonpigmented ciliary epithelium, NPE) induced a sustained increase in short-circuit current (Isc). Addition of niflumic acid (NFA) to the aqueous surface effectively blocked the cAMP-induced Isc stimulation. The administration of cAMP to the stromal side (pigmented ciliary epithelium, PE) triggered a significant stimulation of Isc only at 100 μM. No additive effect was observed with bilateral application of cAMP. Likewise, forskolin caused a significant stimulation of Isc when applied to the aqueous side. Concomitantly, cAMP and forskolin increased fluid transport across porcine ciliary epithelium, and this stimulation was effectively inhibited by aqueous NFA. Depleting Cl- in the bathing solution abolished the baseline Isc and inhibited the subsequent stimulation by cAMP. Pretreatment with protein kinase A (PKA) blockers (H89/KT5720) significantly inhibited the cAMP- and forskolin-induced Isc responses. Our results suggest that cAMP triggers a sustained stimulation of Cl- and fluid transport across porcine ciliary epithelium; Cl- channels in the NPE cells are potentially a cellular site for this PKA-sensitive cAMP-mediated response.

Generation of low KV x-ray portal images with mega-voltage electron beams

International Nuclear Information System (INIS)

Kenny, J.; Ebert, M.

2004-01-01

Full text: The increasing complexity of radiation therapy plans and reduced target margins, have made accurate localization of patients at treatment a crucial quality assurance issue. Mega-voltage portal images, the standard for treatment localization, are inherently low in contrast because x-ray attenuation at these energies is similar for most body tissues. Thus anatomical features are difficult to distinguish and match to features on a reference diagnostic image. This project investigates the possibly of using x-rays created by an external target placed in the path of a clinical mega-voltage electron beam. This target is optimised to produce a higher proportion of useful imaging x-rays in the range of 50-200kV. It is thought that a high efficiency Varian aSi500 amorphous silicon EPID will be sufficient to compensate for the very low efficiency of x-ray production. The project was undertaken with concurrent theoretical and experimental components. The former involved Monte Carlo models of low Z target design while in the later, experimental data was gathered to validate the model and explore the practical issues associated with electron mode image acquisition. A 6 MeV electron beam model for a Varian Clinac 21EX was developed with EGS4/BEAMnrc User Code and compared to measured beam data. Phase space data scored at the secondary collimator then became the input for simulations of a target placed in the accessory tray. Target materials were predominately low atomic number (Z) because a) production of high energy x-rays is minimized and, b) fewer low energy x-rays produced will be absorbed within the target. Photon and electron energy spectrums of the modified beam were evaluated for a range of target geometries. Ultimately, several materials were used in combination to optimise an x-ray yield for energies <200kV while removing electrons and very low energy x-rays, that contribute to patient dose but not to image formation. Low energy images of a PIPs EPID QA

Development and calibration of the tracking Compton/Pair telescope MEGA

International Nuclear Information System (INIS)

Kanbach, G.; Andritschke, R.; Zoglauer, A.; Ajello, M.; McConnell, M.L.; Macri, J.R.; Ryan, J.M.; Bloser, P.; Hunter, S.; DiCocco, G.; Kurfess, J.; Reglero, V.

2005-01-01

We describe the development and tests of the prototype for a new telescope for Medium Energy Gamma-ray Astronomy (MEGA) in the energy band 0.4-50 MeV. As a successor to COMPTEL and EGRET (at low energies), MEGA aims to improve the sensitivity for astronomical sources by at least an order of magnitude. It could thus fill the severe sensitivity gap between scheduled or operating hard-X-ray and high-energy gamma-ray missions and open the way for a future Advanced Compton Telescope. MEGA records and images γ-rays by completely tracking Compton and Pair creation events in a stack of double-sided Si-strip track detectors surrounded by a pixelated CsI calorimeter. A scaled down prototype has been built and we describe technical details of its design and properties. Results from calibrations using radioactive sources and from measurements with an accelerator generated, fully polarized, γ-ray beam are presented and an outlook to future plans with MEGA is given

Low current beam techniques

Energy Technology Data Exchange (ETDEWEB)

Saint, A.; Laird, J.S.; Bardos, R.A.; Legge, G.J.F. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Nishijima, T.; Sekiguchi, H. [Electrotechnical Laboratory, Tsukuba (Japan).

1993-12-31

Since the development of Scanning Transmission Microscopy (STIM) imaging in 1983 many low current beam techniques have been developed for the scanning (ion) microprobe. These include STIM tomography, Ion Beam Induced Current, Ion Beam Micromachining and Microlithography and Ionoluminense. Most of these techniques utilise beam currents of 10{sup -15} A down to single ions controlled by beam switching techniques This paper will discuss some of the low beam current techniques mentioned above, and indicate, some of their recent applications at MARC. A new STIM technique will be introduced that can be used to obtain Z-contrast with STIM resolution. 4 refs., 3 figs.

Low current beam techniques

Energy Technology Data Exchange (ETDEWEB)

Saint, A; Laird, J S; Bardos, R A; Legge, G J.F. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Nishijima, T; Sekiguchi, H [Electrotechnical Laboratory, Tsukuba (Japan).

1994-12-31

Since the development of Scanning Transmission Microscopy (STIM) imaging in 1983 many low current beam techniques have been developed for the scanning (ion) microprobe. These include STIM tomography, Ion Beam Induced Current, Ion Beam Micromachining and Microlithography and Ionoluminense. Most of these techniques utilise beam currents of 10{sup -15} A down to single ions controlled by beam switching techniques This paper will discuss some of the low beam current techniques mentioned above, and indicate, some of their recent applications at MARC. A new STIM technique will be introduced that can be used to obtain Z-contrast with STIM resolution. 4 refs., 3 figs.

Calorimetric beam-current integrator

International Nuclear Information System (INIS)

Osborne, J.L.

1984-01-01

A single-cup calorimeter for beam-current integration and its associated electronics are described. The design allows beam power up to 120 W and is shown to integrate with an accuracy of 1% over a range of beam energy, current, and power. (orig.)

NIKHEF: AmPS of electron beam

International Nuclear Information System (INIS)

Anon.

1992-01-01

Now operational at the Dutch National Institute for Nuclear Physics and High Energy Physics (NIKHEF), Amsterdam, is a new tool for studying the electromagnetic properties of nuclei. Called AmPS - Amsterdam pulse stretcher - this ring provides experiments with a smoother, almost continuous supply of electrons

A ns-pulsed high-current electron beam source

International Nuclear Information System (INIS)

Guan, Gexin; Li, Youzhi; Pan, Yuli

1988-01-01

The behaviour of a pulse electron beam source which is composed of a gun and pulse system depends on not only the time characteristics of the gun and the pulser, but also their combination. This point become apparent if effects of the electron tansit-time between electrodes are studied. A ferrite transmission line (FTL) pulser is used as a grid driver in this source. It has advantages of providing fast risetime, large peak power output and good loading characteristics. It is these advantages of the pulser that compensates the absence of some technological conditions of manufacturing gun and makes the source better. Our testing showed that the cooperation of both the gun and the pulser produced peak currents in the range of 1 to 9 amps with widths of 2 to 2.5 ns (FWHM) at cathode-to-anode potential of 60 to 82 kv, while the grid drives are about in the range of 1 to 3 kv. In addition, the results of the testing instructed that effects of electron transit-time cannot be ignored when the pulses with widths of several nanoseconds are used as a grid drive. Based on the results, electron transit-time effects on the design of the gun and the beam performances are briefly descussed in this paper. (author)

A beam position monitor for low current dc beams

International Nuclear Information System (INIS)

Adderley, P.; Barry, W.; Heefner, J.; Kloeppel, P.; Rossmanith, R.; Wise, M.; Jachim, S.

1989-01-01

The 4 GeV recirculating linac, CEBAF, if presently under construction and will produce a CW beam with average current between.1 and 200 μA. In order to measure beam position, the beam current will be amplitude modulated at a frequency of 10 MHz. The modulation is detected by an inductive loop type monitor with electronics sensitive only to the modulation frequency. The first test with beam from the CEBAF injector indicate that beam position can be measured with an accuracy of .1 mm at a modulated beam current of 1 μA. 1 ref., 6 figs., 1 tab

Results from beam tests of MEGA's low-mass, high-rate cylindrical MWPCs

International Nuclear Information System (INIS)

Stanislaus, S.; Armijo, V.; Black, J.K.; Bolton, R.D.; Carius, S.; Cooper, M.D.; Espinoza, C.; Hart, G.; Hogan, G.; Gonzales, A.; Mischke, R.E.; Piilonen, L.E.; Sandoval, J.; Schilling, S.; Sena, J.; Suazo, G.; Szymanski, J.J.; Whitehouse, D.A.; Wilkinson, C.A.; Fisk, R.; Koetke, D.D.; Manweiler, R.W.; Jui, C.C.

1991-01-01

One of the leading experimental projects at LAMPF has been the MEGA experiment. This is an experiment to search for the rare decay μ → eγ with a sensitivity of 10 -13 . A prime component of this project has been the design and construction of high-rate, low mass MWPCs for the tracking of positrons from muon decay. With rate capabilities of 2 x 10 4 e + /mm 2 /s and a thickness of 3 x 10 -4 radiation lengths, these chambers are state-of-the-art cylindrical MWPCs. Cylindrical chambers of this size (0.9 m 2 ) and thinness have never been previously constructed. The MEGA project at LAMPF has recently succeeded in building chambers with these necessary performance characteristics as demonstrated by data taken from muon decays, cosmic rays, and sources

High current beam transport with multiple beam arrays

International Nuclear Information System (INIS)

Kim, C.H.

1985-05-01

Highlights of recent experimental and theoretical research progress on the high current beam transport of single and multiple beams by the Heavy Ion Fusion Accelerator Research (HIFAR) group at the Lawrence Berkeley Laboratory (LBL) are presented. In the single beam transport experiment (SBTE), stability boundaries and the emittance growth of a space charge dominated beam in a long quadrupole transport channel were measured and compared with theory and computer simulations. Also, a multiple beam ion induction linac (MBE-4) is being constructed at LBL which will permit study of multiple beam transport arrays, and acceleration and bunch length compression of individually focused beamlets. Various design considerations of MBE-4 regarding scaling laws, nonlinear effects, misalignments, and transverse and longitudinal space charge effects are summarized. Some aspects of longitudinal beam dynamics including schemes to generate the accelerating voltage waveforms and to amplify beam current are also discussed

Effects of electron beam irradiation on inorganic exchanger AMP

International Nuclear Information System (INIS)

Rao, K.L.N.; Mathew, C.; Deshpande, R.S.; Jadhav, A.V.; Pande, B.M.; Shukla, J.P.

1996-01-01

The heteropolyacid salt inorganic exchanger ammonium molybdophosphate (AMP) was subjected to an electron dose upto 2 MGy to assess any possible radiation damage. The breakthrough and total exchange capacity of AMP for Cs + from simulated fission product solutions were determined for both control and irradiated samples. The scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDX) were deployed to examine any marked microscopic changes taking place in this exchanger. (author). 3 refs., 3 figs

LANSCE Beam Current Limiter (XL)

International Nuclear Information System (INIS)

Gallegos, F.R.; Hall, M.J.

1997-01-01

The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) is an engineered safety system that provides personnel protection from prompt radiation due to accelerated proton beams. The Beam Current Limiter (XL), as an active component of the RSS, limits the maximum average current in a beamline, thus the current available for a beam spill accident. Exceeding the pre-set limit initiates action by the RSS to mitigate the hazard (insertion of beam stoppers in the low energy beam transport). The beam limiter is an electrically isolated, toroidal transformer and associated electronics. The device was designed to continuously monitor beamline currents independent of any external timing. Fail-safe operation was a prime consideration in its development. Fail-safe operation is defined as functioning as intended (due to redundant circuitry), functioning with a more sensitive fault threshold, or generating a fault condition. This report describes the design philosophy, hardware, implementation, operation, and limitations of the device

Current neutralization of nanosecond risetime, high-current electron beam

International Nuclear Information System (INIS)

Lidestri, J.P.; Spence, P.W.; Bailey, V.L.; Putnam, S.D.; Fockler, J.; Eichenberger, C.; Champney, P.D.

1991-01-01

This paper reports that the authors have recently investigated methods to achieve current neutralization in fast risetime (<3 ns) electron beams propagating in low-pressure gas. For this investigation, they injected a 3-MV, 30-kA intense beam into a drift cell containing gas pressures from 0.10 to 20 torr. By using a fast net current monitor (100-ps risetime), it was possible to observe beam front gas breakdown phenomena and to optimize the drift cell gas pressure to achieve maximum current neutralization. Experimental observations have shown that by increasing the drift gas pressure (P ∼ 12.5 torr) to decrease the mean time between secondary electron/gas collisions, the beam can propagate with 90% current neutralization for the full beam pulsewidth (16 ns)

80 kV electrostatic wire septum for AmPS

International Nuclear Information System (INIS)

Linden, A. van der; Bijleveld, J.H.M.; Rookhuizen, H.B.; Bruinsma, P.J.T.; Heine, E.; Lassing, P.; Prins, E.

1992-01-01

The Amsterdam Pulse Stretcher (AmPS) ring aims at a 100% duty cycle operation by means of slow extraction of injected electron beam pulses of 2.1 μs. In the extraction process of the AmPS, the extracted beam is intercepted from the circulating beam by the 1 m long electrostatic wire septum. For a bending angle of 4.4 mrad the maximum anode voltage is 80 kV. Care has been given to the electric field distribution at the entrance and exit of the septum and to the insulators, required to support the anode. Prototype tests have been successful up to an anode voltage of 120 kV. (R.P.) 9 refs.; 5 figs

Mega-Analysis of School Psychology Blueprint for Training and Practice Domains

Science.gov (United States)

Burns, Matthew K.; Kanive, Rebecca; Zaslofsky, Anne F.; Parker, David C.

2013-01-01

Meta-analytic research is an effective method for synthesizing existing research and for informing practice and policy. Hattie (2009) suggested that meta-analytic procedures could be employed to existing meta-analyses to create a mega-analysis. The current mega-analysis examined a sample of 47 meta-analyses according to the "School…

Squid based beam current meter

International Nuclear Information System (INIS)

Kuchnir, M.

1983-01-01

A SQUID based beam current meter has the capability of measuring the current of a beam with as little as 30 x 155 antiprotons (with a signal to noise ratio of 2). If low noise dc current is used to cancel most of the beam or an up-down counter is used to count auto-resets this sensitivity will be available at any time in the acumulation process. This current meter will therefore be a unique diagnostic tool for optimizing the performance of several Tev I components. Besides requiring liquid helium it seems that its only drawback is not to follow with the above sensitivity a sudden beam change larger than 16 μA, something that could be done using a second one in a less sensitive configuration

Crane RF accelerator for high current radiation damage studies

International Nuclear Information System (INIS)

Whitham, K.; Anamkath, H.; Evans, K.; Lyons, S.; Palmer, D.; Miller, R.; Treas, P.; Zante, T.

1992-01-01

An electron accelerator was designed and built for the Naval Weapons Support Center for transient radiation effects on electronics experiments and testing. The Crane L Band RF Electron Linac was designed to provide high currents over a wide range of pulse widths and energies. The energy extends to 60 MeV and pulse widths vary from a few ns to 10 μsec. Beam currents range from 20 amps in the short pulse case to 1.5 amps in the long pulse case. This paper describes the linac, its architecture, the e-gun and pulser, waveguides, klystrons and modulator, vacuum system, beam transport, and control systems. fig., tab

Tutorial on beam current monitoring

International Nuclear Information System (INIS)

Webber, Robert C.

2000-01-01

This paper is a tutorial level review covering a wide range of aspects related to charged particle beam current measurement. The tutorial begins with a look at the characteristics of the beam as a signal source, the associated electromagnetic fields, the influence of the typical accelerator environment on those fields, and the usual means of modifying and controlling that environment to facilitate beam current measurement. Short descriptions of three quite different types of current monitors are presented and a quantitative review of the classical transformer circuit is given. Recognizing that environmental noise pick-up may present a large source of error in quantitative measurements, signal handling considerations are given considerable attention using real-life examples. An example of a successful transport line beam current monitor implementation is presented and the tutorial concludes with a few comments about signal processing and current monitor calibration issues

The LANSCE Low Momentum Beam Monitor

CERN Document Server

Merl, R

2004-01-01

A diagnostic has been developed at the Los Alamos Neutron Science Center (LANSCE) for the purpose of identifying low momentum beam tails in the linear accelerator. These tails must be eliminated in order to maintain the transverse and longitudinal beam size. Instead of the currently used phosphor camera system, this instrument consists of a Multi Wire Proportional Chamber (MWPC) front end coupled to an EPICS compliant VME-based electronics package. Low momentum tails are detected with a resolution of 5 mm in the MWPC at a high dispersion point near a bending magnet. While phosphor is typically not sensitive in the nano amp range, the MWPC is sensitive down to about a pico amp. The electronics package processes the signals from each of the MWPC wires to generate an array of beam currents at each of the lower energies. The electronics has an analog front end with a high-speed analog to digital converter for each wire. Data from multiple wires are processed with an embedded digital signal processor and results p...

Current results for μ→e+γ decay search with the MEGA experiment

International Nuclear Information System (INIS)

Zhang, Y.

1993-01-01

The MEGA experiment at LAMPF is designed to search for the rare decay μ → e+γ with a branching ratio sensitivity of 4x10 -13 . The detector consists of an electron spectrometer (a set of low-mass MPWCs and two barrels of scintillators) and a photon arm (three-layer pair spectrometer) in a 1.5-T solenoidal magnetic field. The experimental design maximizes rate capability, retains large solid angle, and suppresses the background to below the experimental sensitivity. In the summer of 1992, the MEGA collaboration successfully finished whole-system tests and got 163.6 million μ→E+γ candidate events by using the electron arm and two of the three photon pair spectrometers. The status of the data analysis will be described

Sensitive beam current measurement for FAIR

Energy Technology Data Exchange (ETDEWEB)

Schwickert, Marcus; Kurian, Febin; Reeg, Hansjoerg [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Seidel, Paul; Neubert, Ralf [Friedrich-Schiller-Universitaet Jena (Germany); Geithner, Rene; Vodel, Wolfgang [Helmholtz-Institut Jena (Germany)

2012-07-01

Presently FAIR, the Facility for Antiproton and Ion Research, entered the final planning phase at GSI. The new accelerator facility requires precise devices for beam current measurements due to the large dynamics in beam intensities for the various synchrotrons, transport lines and storage rings. We report on the actual developments of beam diagnostic devices for the measurement of beam intensities ranging from 5 x 10{sup 11} uranium ions down to the detection of less than 10{sup 4} antiprotons. This contribution gives an overview of the planned instruments with a focus on non-intercepting beam current transformers, and summarizes the on-going development of a cryogenic current comparator.

High current density ion beam measurement techniques

International Nuclear Information System (INIS)

Ko, W.C.; Sawatzky, E.

1976-01-01

High ion beam current measurements are difficult due to the presence of the secondary particles and beam neutralization. For long Faraday cages, true current can be obtained only by negative bias on the target and by summing the cage wall and target currents; otherwise, the beam will be greatly distorted. For short Faraday cages, a combination of small magnetic field and the negative target bias results in correct beam current. Either component alone does not give true current

High bandwidth beam current monitor

International Nuclear Information System (INIS)

Baltrusaitis, R.M.; Ekdahl, C.A.; Cooper, R.G.; Peterson, E.; Warn, C.E.

1993-01-01

A stripline directional coupler beam current monitor capable of measuring the time structure of a 30-ps electron beam bunch has been developed. The time response performance of the monitor compares very well with Cherenkov light produced in quartz by the electron beam. The four-pickup monitor is now used on a routine basis for measuring the beam duration, tuning for optimized beam bunching, and centering the bunch in the beam pipe

Digitally compensated beam current transformer

International Nuclear Information System (INIS)

Kesselman, Martin

2005-01-01

The Spallation Neutron Source (SNS) is being built by a collaboration of six laboratories. Beam current monitors (BCMs) will be used to record the current of H-minus and H-plus beams ranging from 15 mA (tune-up in the Front End and Linac) to over 60A fully accumulated in the Ring and dumped to the load as a single pulse in the Ring to Beam Target (RTBT). The time structure of these beams ranges from 645 ns 'mini' bunches at the 1.05 MHz ring revolution rate, to an overall 1 ms long macro-pulse. The requirements for the BCMs will depend upon their location within the system. The need to measure individual mini-pulses, examine the characteristics of the chopper edge, as well as the longer average current pulse of the macropulse, or long duration pulses during Linac tuning place wide requirements upon the response of current transformers. To obtain the desired accuracy and resolution, current transformers must have <1 ns rise time and droops of 0.1%/ms. This places a significant design burden on the current transformer; such a design is almost impossible to achieve. Extremely large expensive cores are needed to meet the low droop, while leakage inductance increases with size, thereby reducing the achievable rise time. In this paper, I discuss a digital compensation approach [M. Kesselman, Spallation neutron source beam current monitor electronics, PAC2001 June 18-22, 2001, Chicago, IL.] that extends the lower cut-off frequency of the current transformer, optimized for high frequency response, so that it can be used in this application with improvements in droop of the order of 1000:1. Transformer saturation (current-time product) is a separate issue and the transformer must be designed to handle the current-time product of the signal to assure it does not saturate

Online diagnoses of high current-density beams

International Nuclear Information System (INIS)

Gilpatrick, J.D.

1994-01-01

Los Alamos National Laboratory has proposed several CW-proton-beam facilities for production of tritium or transmutation of nuclear waste with beam-current densities greater than 5 mA/mm 2 . The primary beam-diagnostics-instrumentation requirement for these facilities is provision of sufficient beam information to understand and minimize beam-loss. To accomplish this task, the beam-diagnostics instrumentation must measure beam parameters such as the centroids and profiles, total integrated current, and particle loss. Noninterceptive techniques must be used for diagnosis of high-intensity CW beam at low energies due to the large quantity of power deposited in an interceptive diagnostic device by the beam. Transverse and longitudinal centroid measurements have been developed for bunched beams by measuring and processing image currents on the accelerator walls. Transverse beam-profile measurement-techniques have also been developed using the interaction of the particle beam with the background gases near the beam region. This paper will discuss these noninterceptive diagnostic Techniques

Precision intercomparison of beam current monitors at CEBAF

International Nuclear Information System (INIS)

Kazimi, R.; Dunham, B.; Krafft, G.A.; Legg, R.; Liang, C.; Sinclair, C.; Mamosser, J.

1995-01-01

The CEBAF accelerator delivers a CW electron beam at fundamental 1497 MHz, with average beam current up to 200 μA. Accurate, stable nonintercepting beam current monitors are required for: setup/control, monitoring of beam current and beam losses for machine protection and personnel safety, and providing beam current information to experimental users. Fundamental frequency stainless steel RF cavities have been chosen for these beam current monitors. This paper reports on precision intercomparison between two such RF cavities, an Unser monitor, and two Faraday cups, all located in the injector area. At the low beam energy in the injector, it is straightforward to verify the high efficiency of the Faraday cups, and the Unser monitor included a wire through it to permit an absolute calibration. The cavity intensity monitors have proven capable of stable, high precision monitoring of the beam current

Aircushion Supported Mega-Floaters

NARCIS (Netherlands)

Van Kessel, J.L.F.

2010-01-01

The increase of the global population and expanding coastal mega-cities will necessitate an innovative pursuit of the utilization of the ocean space in which mega-floaters will play an important role in the future. These types of structures are very large floating artificial islands that can be used

The Spallation Neutron Source Beam Commissioning and Initial Operations

Energy Technology Data Exchange (ETDEWEB)

Henderson, Stuart [Argonne National Lab. (ANL), Argonne, IL (United States); Aleksandrov, Alexander V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Allen, Christopher K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Assadi, Saeed [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bartoski, Dirk [University of Texas, Houston, TX (United States). Anderson Cancer Center; Blokland, Willem [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Casagrande, F. [Michigan State Univ., East Lansing, MI (United States); Campisi, I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chu, C. [Michigan State Univ., East Lansing, MI (United States); Cousineau, Sarah M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Crofford, Mark T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Danilov, Viatcheslav [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Deibele, Craig E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dodson, George W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Feshenko, A. [Inst. for Nuclear Research (INR), Moscow (Russian Federation); Galambos, John D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Han, Baoxi [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hardek, T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holmes, Jeffrey A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holtkamp, N. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Howell, Matthew P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jeon, D. [Inst. for Basic Science, Daejeon (Korea); Kang, Yoon W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kasemir, Kay [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kim, Sang-Ho [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kravchuk, L. [Institute for Nuclear Research (INR), Moscow (Russian Federation); Long, Cary D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); McManamy, T. [McManamy Consulting, Inc., Middlesex, MA (United States); Pelaia, II, Tom [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Piller, Chip [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Plum, Michael A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pogge, James R. [Tennessee Technological Univ., Cookeville, TN (United States); Purcell, John David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shea, T. [European Spallation Source, Lund (Sweden); Shishlo, Andrei P [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sibley, C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stockli, Martin P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stout, D. [Michigan State Univ., East Lansing, MI (United States); Tanke, E. [European Spallation Source, Lund (Sweden); Welton, Robert F [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Zhang, Y. [Michigan State Univ., East Lansing, MI (United States); Zhukov, Alexander P [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2015-09-01

The Spallation Neutron Source (SNS) accelerator delivers a one mega-Watt beam to a mercury target to produce neutrons used for neutron scattering materials research. It delivers ~ 1 GeV protons in short (< 1 us) pulses at 60 Hz. At an average power of ~ one mega-Watt, it is the highest-powered pulsed proton accelerator. The accelerator includes the first use of superconducting RF acceleration for a pulsed protons at this energy. The storage ring used to create the short time structure has record peak particle per pulse intensity. Beam commissioning took place in a staged manner during the construction phase of SNS. After the construction, neutron production operations began within a few months, and one mega-Watt operation was achieved within three years. The methods used to commission the beam and the experiences during initial operation are discussed.

rf beam-current, -phase, and -position monitors

International Nuclear Information System (INIS)

Young, L.

1984-01-01

A prototype rf beam monitor has been tested on the Racetrack Microtron's (RTM) 100 kV injector beam line at the National Bureau of Standards (NBS). This beam monitor is capable of measuring the current, the relative phase, and the position of the beam. The beam is bunched at 2380 MHz for acceleration by the linac in the injector beam line. This train of beam bunches passing through the beam monitor cavities excites the cavities at this resonance frequency of 2380 MHz. Probes in the cavities couple some of the beam-excited rf power out of the cavities. This rf power can be amplified if necessary and then analyzed by a double balanced mixer (DBM). The DBM can also be used as a phase detector. The effective shunt impedance of the cavities was measured with the CW beam. For the position monitor cavity, the shunt impedance is proportional to the displacement from the axis. The measured response of the prototype rf beam current monitor setup is a linear function of beam current. Response of the rf beam-position monitor is also shown

Neutral-beam current drive in tokamaks

International Nuclear Information System (INIS)

Devoto, R.S.

1986-01-01

The theory of neutral-beam current drive in tokamaks is reviewed. Experiments are discussed where neutral beams have been used to drive current directly and also indirectly through neoclassical effects. Application of the theory to an experimental test reactor is described. It is shown that neutral beams formed from negative ions accelerated to 500 to 700 keV are needed for this device

Neutral-beam current drive in tokamaks

International Nuclear Information System (INIS)

Devoto, R.S.

1987-01-01

The theory of neutral-beam current drive in tokamaks is reviewed. Experiments are discussed where neutral beams have been used to drive current directly and also indirectly through neoclassical effects. Application of the theory to an experimental test reactor is described. It is shown that neutral beams formed from negative ions accelerated to 500-700 keV are needed for this device

SNS project-wide beam current monitors

International Nuclear Information System (INIS)

Kesselman, M.; Witkover, R.; Doolittle, L.; Power, J.

2000-01-01

A consortium of national laboratories is constructing the Spallation Neutron Source [1] (SNS) to be installed at Oak Ridge National Laboratory. There are signal similarities that exist in the beam diagnostic instrumentation that could permit common designs. This paper will focus on the beam current monitoring requirements, and the methods under consideration to measure beam current in various locations throughout the SNS facility

MEGA: A Low-Background Radiation Detector

International Nuclear Information System (INIS)

Kazkaz, Kareem; Aalseth, Craig E.; Hossbach, Todd W.; Gehman, Victor M.; Kephart, Jeremy; Miley, Harry S.

2004-01-01

The multiple-element gamma assay (MEGA) is a low-background detector designed to support environmental monitoring and national security applications. MEGA also demonstrates technology needed or Majorana, a next generation neutrino mass experiment. It will also exploit multicoincidence signatures to identify specific radioactive isotopes. MEGA is expected to begin testing in late 2003 for eventual installation at the Waste Isolation Plant, Carlsbad, NM

The primary opinion on the formation mechanisms of mega dunes and lakes in the Badain jaran desert

International Nuclear Information System (INIS)

Guo Yonghai; Li Yawei

2010-01-01

Badain Jaran Desert is famous in distribution of many lakes and mega dunes in the world. Up to now, there are several different opinions about formation problems of lakes and mega dunes. Actually, these problems are directly correlated to the groundwater circulation and alternation in the area. Refering to the prevenient research results and combining with the current hydrogeological investigation in the desert, the paper discussed the problems about the formation mechanisms of lakes and mega dunes. The Primary cognition is that: the lakes in the desert were formed mainly by the lateral recharge of groundwaters both from Yabulai mountain and mega dunes. The formation of the mega dunes was related nearly to the rainfall and groundwater in the area. The formation and coexistence relationship between lakes and mega dunes is that: the mega dunes were formed firstly, and then the lakes. That is to say the mega dunes are the basic conditions for the lake formation. (authors)

Current neutralization of converging ion beams

International Nuclear Information System (INIS)

Mosher, D.

1978-01-01

It is desired to consider the problem of current neutralization of heavy ion beams traversing gas backgrounds in which the conductivity changes due to beam heating and beam convergence. The procedure is to determine Green's-function solutions to the magnetic-diffusion equation derived from Maxwell's equations and an assumed scaler-plasma conductivity sigma for the background-electron current density j/sub e/. The present calculation is more general than some previously carried out in that arbitrary time variations for the beam current j/sub b/ and conductivity are allowed and the calculation is valid for both weak and strong neutralization. Results presented here must be combined with an appropriate energy-balance equation for the heated background in order to obtain the neutralization self-consistently

Multigigahertz beam-current and position monitor

International Nuclear Information System (INIS)

Carlson, R.L.; Stout, L.E.

1985-01-01

A self-integrating magnetic-loop device having a risetime of less than 175 ps has been developed to monitor the temporal behavior of the electron beam current and position within each 3.3-ns micropulse generated by the PHERMEX rf linear accelerator. Beam current is measured with a 2-GHz bandwidth by combining these loops in a four-port hybrid summer. Another application of these loops uses two 180 0 hybrids to give 2-GHz time-resolved beam position to an accuracy of 1 mm. These sensors are nonintrusive to the propagating beam and allow ultrafast beam measurements previously restricted to the technique of recording the Cerenkov-light emission from an intercepting Kapton foil using a streak camera

Aspectos da miocardite em chagásicos crônicos com "megas" e sem "megas" com insuficiência cardíaca congestiva

Directory of Open Access Journals (Sweden)

Hipólito de Oliveira Almeida

1984-06-01

Full Text Available O estudo microscópico de 20 corações de chagásicos com "megas" e de outros 20 sem "megas" com insuficiência cardíaca congestiva (ICC revelou que tanto a Jibrose quanto o exsudato inflamatório no miocárdio são discretos nos casos de "megas" e geralmente acentuados nos casos de ICC. Considerando-se que nos "megas" a ICC, a hipertrofia do miocárdio e a lesão vorticilar são fenômenos raros, nossos achados (atuais e anteriores sugerem que estes estejam relacionados principalmente com a agressão inflamatória ao miocárdio ventricular, uma vez que a desnervação é, geralmente, mais acentuada nos casos de "megas" que nos de ICC.The study of 20 hearts from chagasic patients with "megas " and of others 20 from chagasics without "megas" with heart failure, shows that both, myocardial Jibrosis and inflammatory exudate are light in cases with "megas" and severe in group with heart failure. In chagasic with "megas" the myocardial hypertrophy, the apical lesion and the cardiac insufficiency are infrequent. Ourfindings suggest that they are related to the myocardial ventricular inflammation and not to the cardiac denervation. This latter is more severe in cases of "megas" than in cases of congestive heart failure without "megas".

Optimal Design for Reactivity Ratio Estimation: A Comparison of Techniques for AMPS/Acrylamide and AMPS/Acrylic Acid Copolymerizations

Directory of Open Access Journals (Sweden)

Alison J. Scott

2015-11-01

Full Text Available Water-soluble polymers of acrylamide (AAm and acrylic acid (AAc have significant potential in enhanced oil recovery, as well as in other specialty applications. To improve the shear strength of the polymer, a third comonomer, 2-acrylamido-2-methylpropane sulfonic acid (AMPS, can be added to the pre-polymerization mixture. Copolymerization kinetics of AAm/AAc are well studied, but little is known about the other comonomer pairs (AMPS/AAm and AMPS/AAc. Hence, reactivity ratios for AMPS/AAm and AMPS/AAc copolymerization must be established first. A key aspect in the estimation of reliable reactivity ratios is design of experiments, which minimizes the number of experiments and provides increased information content (resulting in more precise parameter estimates. However, design of experiments is hardly ever used during copolymerization parameter estimation schemes. In the current work, copolymerization experiments for both AMPS/AAm and AMPS/AAc are designed using two optimal techniques (Tidwell-Mortimer and the error-in-variables-model (EVM. From these optimally designed experiments, accurate reactivity ratio estimates are determined for AMPS/AAm (rAMPS = 0.18, rAAm = 0.85 and AMPS/AAc (rAMPS = 0.19, rAAc = 0.86.

Didactical formulation of the Ampère law

International Nuclear Information System (INIS)

Barchiesi, Dominique

2014-01-01

The Ampère law is useful to calculate the magnetostatic field in the cases of distributions of current with high degree of symmetry. Nevertheless the magnetic field produced by a thin straight wire carrying a current I requires the Biot–Savart law and the use of the Ampère law leads to a mistake. A didactical formulation of the Ampère law is proposed to prevent misinterpretations. (letters and comments)

Monitoring tumor motion with on-line mega-voltage cone-beam computed tomography imaging in a cine mode

International Nuclear Information System (INIS)

Reitz, Bodo; Gayou, Olivier; Parda, David S; Miften, Moyed

2008-01-01

Accurate daily patient localization is becoming increasingly important in external-beam radiotherapy (RT). Mega-voltage cone-beam computed tomography (MV-CBCT) utilizing a therapy beam and an on-board electronic portal imager can be used to localize tumor volumes and verify the patient's position prior to treatment. MV-CBCT produces a static volumetric image and therefore can only account for inter-fractional changes. In this work, the feasibility of using the MV-CBCT raw data as a fluoroscopic series of portal images to monitor tumor changes due to e.g. respiratory motion was investigated. A method was developed to read and convert the CB raw data into a cine. To improve the contrast-to-noise ratio on the MV-CB projection data, image post-processing with filtering techniques was investigated. Volumes of interest from the planning CT were projected onto the MV-cine. Because of the small exposure and the varying thickness of the patient depending on the projection angle, soft-tissue contrast was limited. Tumor visibility as a function of tumor size and projection angle was studied. The method was well suited in the upper chest, where motion of the tumor as well as of the diaphragm could be clearly seen. In the cases of patients with non-small cell lung cancer with medium or large tumor masses, we verified that the tumor mass was always located within the PTV despite respiratory motion. However for small tumors the method is less applicable, because the visibility of those targets becomes marginal. Evaluation of motion in non-superior-inferior directions might also be limited for small tumor masses. Viewing MV-CBCT data in a cine mode adds to the utility of MV-CBCT for verification of tumor motion and for deriving individualized treatment margins

Deep sea mega-geomorphology: Progress and problems

Science.gov (United States)

Bryan, W. B.

1985-01-01

Historically, marine geologists have always worked with mega-scale morphology. This is a consequence both of the scale of the ocean basins and of the low resolution of the observational remote sensing tools available until very recently. In fact, studies of deep sea morphology have suffered from a serious gap in observational scale. Traditional wide-beam echo sounding gave images on a scale of miles, while deep sea photography has been limited to scales of a few tens of meters. Recent development of modern narrow-beam echo sounding coupled with computer-controlled swath mapping systems, and development of high-resolution deep-towed side-scan sonar, are rapidly filling in the scale gap. These technologies also can resolve morphologic detail on a scale of a few meters or less. As has also been true in planetary imaging projects, the ability to observe phenomena over a range of scales has proved very effective in both defining processes and in placing them in proper context.

Computer simulation of electron beams. II. Low-cost beam-current reconstruction

International Nuclear Information System (INIS)

de Wolf, D.A.

1985-01-01

Reconstruction of current density in electron beams is complicated by distortion of phase space which can require very fine discretization of the beam into trajectories. An efficient discretization of phase space is exploited, using conservation of charge and current in hypertriangle patches, to reconstruct the current density by fitting Gaussians through the distorted hypertriangles. Advantages and limitations are discussed

Assessment of Electron Beam Welding in Shipyard Construction,

Science.gov (United States)

1985-12-01

ELECTRON BEAM APPLICATORS QUESTIONNAIRE 1. Applicators Name: McCay Tool & Engr. Co. 2. Address: 1449 West Lark, Fenton , Mo. 3...had very li tt le undercut and requ ired no cosmet ic pass. TESTING AND RESULTS ’re~t ing wi ~ pt-f’)rimev oil spc inens inl t he- fol lowing manner. 1...Penetration Cosmet . c Accelerating Voltage (KV) 75 70 Beam Current (ma) 115 30 Travel Speed (IPM) 8 18 Beam focus (Amps programmed) 4.38 4.70 Gun to Work

Charge neutralization of small ion beam clumps

Energy Technology Data Exchange (ETDEWEB)

Welch, D R [Mission Research Corp., Albuquerque, NM (United States); Olson, C L; Hanson, D L [Sandia National Labs., Albuquerque, NM (United States)

1997-12-31

The mega-ampere currents associated with light ion fusion (LIF) require excellent charge neutralization to prevent divergence growth. As the size and space-charge potential of a beam clump or `beamlet` become small (submillimeter size and kilovolt potentials), the neutralization becomes increasingly difficult. Linear theory predicts that plasma electrons cannot neutralize potentials < {phi}{sub crit} = (1/2)m{sub e}v{sub i}{sup 2}/e, where m{sub e} is the electron mass and v{sub i} is the ion beam velocity. A non-uniform beam would, therefore, have regions with potentials sufficient to add divergence to beam clumps. The neutralization of small beamlets produced on the SABLE accelerator and in numerical simulation has supported the theory, showing a plateau in divergence growths as the potential in the beamlet exceeds {phi}{sub crit}. (author). 1 tab., 2 figs., 4 refs.

Dynamic neutral beam current and voltage control to improve beam efficacy in tokamaks

Science.gov (United States)

Pace, D. C.; Austin, M. E.; Bardoczi, L.; Collins, C. S.; Crowley, B.; Davis, E.; Du, X.; Ferron, J.; Grierson, B. A.; Heidbrink, W. W.; Holcomb, C. T.; McKee, G. R.; Pawley, C.; Petty, C. C.; Podestà, M.; Rauch, J.; Scoville, J. T.; Spong, D. A.; Thome, K. E.; Van Zeeland, M. A.; Varela, J.; Victor, B.

2018-05-01

An engineering upgrade to the neutral beam system at the DIII-D tokamak [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] enables time-dependent programming of the beam voltage and current. Initial application of this capability involves pre-programmed beam voltage and current injected into plasmas that are known to be susceptible to instabilities that are driven by energetic ( E ≥ 40 keV) beam ions. These instabilities, here all Alfvén eigenmodes (AEs), increase the transport of the beam ions beyond a classical expectation based on particle drifts and collisions. Injecting neutral beam power, P beam ≥ 2 MW, at reduced voltage with increased current reduces the drive for Alfvénic instabilities and results in improved ion confinement. In lower-confinement plasmas, this technique is applied to eliminate the presence of AEs across the mid-radius of the plasmas. Simulations of those plasmas indicate that the mode drive is decreased and the radial extent of the remaining modes is reduced compared to a higher beam voltage case. In higher-confinement plasmas, this technique reduces AE activity in the far edge and results in an interesting scenario of beam current drive improving as the beam voltage reduces from 80 kV to 65 kV.

Mega-pixel PQR laser chips for interconnect, display ITS, and biocell-tweezers OEIC

Science.gov (United States)

Kwon, O'Dae; Yoon, J. H.; Kim, D. K.; Kim, Y. C.; Lee, S. E.; Kim, S. S.

2008-02-01

We describe a photonic quantum ring (PQR) laser device of three dimensional toroidal whispering gallery cavity. We have succeeded in fabricating the first genuine mega-pixel laser chips via regular semiconductor technology. This has been realized since the present injection laser emitting surface-normal dominant 3D whispering gallery modes (WGMs) can be operated CW with extremely low operating currents (μA-nA per pixel), together with the lasing temperature stabilities well above 140 deg C with minimal redshifts, which solves the well-known integration problems facing the conventional VCSEL. Such properties unusual for quantum well lasers become usual because the active region, involving vertically confining DBR structure in addition to the 2D concave WGM geometry, induces a 'photonic quantum ring (PQR)-like' carrier distribution through a photonic quantum corral effect. A few applications of such mega-pixel PQR chips are explained as follows: (A) Next-generation 3D semiconductor technologies demand a strategy on the inter-chip and intra-chip optical interconnect schemes with a key to the high-density emitter array. (B) Due to mounting traffic problems and fatalities ITS technology today is looking for a revolutionary change in the technology. We will thus outline how 'SLEEP-ITS' can emerge with the PQR's position-sensing capability. (C) We describe a recent PQR 'hole' laser of convex WGM: Mega-pixel PQR 'hole' laser chips are even easier to fabricate than PQR 'mesa' lasers. Genuine Laguerre-Gaussian (LG) beam patterns of PQR holes are very promising for biocell manipulations like sorting mouse myeloid leukemia (M1s) cells. (D) Energy saving and 3D speckle-free POR laser can outdo LEDs in view of red GaAs and blue GaN devices fabricated recently.

Glow-discharge-created electron beams and beam-excited lasers

International Nuclear Information System (INIS)

Meyer, J.D.

1989-01-01

Efficiently created glow discharge electron beams have been developed and studied in detail. The beam mode of operation occurs in the abnormal glow adjacent to the glow-to-arc transition regime. In contrast to electron beams generated in high vacuum from thermionic electron emitting sources, this type of discharge creates electrons directly in soft vacuum by secondary electron emission from cold cathode surfaces following the bombardment of the cathode surface by fast ions and neutral atoms. Factors influencing the efficient electron emission from cold cathodes are presented with emphasis on cathode materials. Sintered ceramic-metal cathodes and oxide-coated cathodes are presented, both of which can produce high power, efficiently generated, d.c. electron beams with discharge currents up to 1 amp (∼130 mA/cm 2 ) at volt ages of up to 6 kV. Novel cathode designs and discharge geometries are presented with specific emphasis on both self-focussed beams emitted from circular cathodes and line-source electron beams emitted from rectangular cathodes forming a thin sheet of electrons. Electrostatically focussed line-source electron beams are spatially characterized by experimentally measuring the effect of discharge parameters and cathode design upon the focussed beam width, focal point, and uniformity. This is achieved by scanning a current collecting detector in three dimensions in order to profile the distribution of electron beam current. Discharge electron beams are further characterized by their electron energy distribution. Measured electron flux energy distributions of transmitted beam electrons in the negative glow are compared to theoretical models. The relative effects of elastic and inelastic collisions mechanisms upon both the overall form and detailed structure of the energy distribution are discussed

Temperate and boreal forest mega-fires: characteristics and challenges

Science.gov (United States)

Scott L. Stephens; Neil Burrows; Alexander Buyantuyev; Robert W. Gray; Robert E. Keane; Rick Kubian; Shirong Liu; Francisco Seijo; Lifu Shu; Kevin G. Tolhurst; Jan W. van Wagtendonk

2014-01-01

Mega-fires are often defined according to their size and intensity but are more accurately described by their socioeconomic impacts. Three factors - climate change, fire exclusion, and antecedent disturbance, collectively referred to as the "mega-fire triangle" - likely contribute to today's mega-fires. Some characteristics of mega-fires may emulate...

Limiting currents of overcompensated electron beams

International Nuclear Information System (INIS)

Malafaev, V.A.

1990-01-01

A possibility of producing recompensated electron beam and increasing its limiting currents in the magnetic field is experimentally investigated. It is shown that such a possibility is realized when the beam is surrounded by a cylindrical net placed into the tube located under the positive potential relative to the net. In this case an increase of limiting current at the expense of increasing the ion life time, takes place. Current, exceeding the Pierce threshold 1.5 times, is obtained

Current neutralization in ballistic transport of light ion beams

International Nuclear Information System (INIS)

Hubbard, R.F.; Slinker, S.P.; Lampe, M.; Joyce, G.; Ottinger, P.

1992-01-01

Intense light ion beams are being considered as drivers to ignite fusion targets in the Laboratory Microfusion Facility (LMF). Ballistic transport of these beams from the diode to the target is possible only if the beam current is almost completely neutralized by plasma currents. This paper summarizes related work on relativistic electron beam and heavy ion beam propagation and describes a simple simulation model (DYNAPROP) which has been modified to treat light ion beam propagation. DYNAPROP uses an envelope equation to treat beam dynamics and uses rate equations to describe plasma and conductivity generation. The model has been applied both to the high current, 30 MeV Li +3 beams for LMF as well as low current, 1.2 MeV proton beams which are currently being studied on GAMBLE B at the Naval Research Laboratory. The predicted ratio of net currents to beam current is ∼0.1--0.2 for the GAMBLE experiment and ∼0.01 for LMF. The implications of these results for LMF and the GAMBLE experiments art discussed in some detail. The simple resistive model in DYNAPROP has well-known limitations in the 1 torr regime which arise primarily from the neglect of plasma electron transport. Alternative methods for treating the plasma response are discussed

Development of high current electron beam generator

Energy Technology Data Exchange (ETDEWEB)

Lee, Byeong Cheol; Lee, Jong Min; Kim, Sun Kook [and others

1997-05-01

A high-current electron beam generator has been developed. The energy and the average current of the electron beam are 2 MeV and 50 mA, respectively. The electron beam generator is composed of an electron gun, RF acceleration cavities, a 260-kW RF generator, electron beam optics components, and control system, etc. The electron beam generator will be used for the development of a millimeter-wave free-electron laser and a high average power infrared free-electron laser. The machine will also be used as a user facility in nuclear industry, environment industry, semiconductor industry, chemical industry, etc. (author). 15 tabs., 85 figs.

Development of high current electron beam generator

International Nuclear Information System (INIS)

Lee, Byeong Cheol; Lee, Jong Min; Kim, Sun Kook

1997-05-01

A high-current electron beam generator has been developed. The energy and the average current of the electron beam are 2 MeV and 50 mA, respectively. The electron beam generator is composed of an electron gun, RF acceleration cavities, a 260-kW RF generator, electron beam optics components, and control system, etc. The electron beam generator will be used for the development of a millimeter-wave free-electron laser and a high average power infrared free-electron laser. The machine will also be used as a user facility in nuclear industry, environment industry, semiconductor industry, chemical industry, etc. (author). 15 tabs., 85 figs

MEGA X: Molecular Evolutionary Genetics Analysis across Computing Platforms.

Science.gov (United States)

Kumar, Sudhir; Stecher, Glen; Li, Michael; Knyaz, Christina; Tamura, Koichiro

2018-06-01

The Molecular Evolutionary Genetics Analysis (Mega) software implements many analytical methods and tools for phylogenomics and phylomedicine. Here, we report a transformation of Mega to enable cross-platform use on Microsoft Windows and Linux operating systems. Mega X does not require virtualization or emulation software and provides a uniform user experience across platforms. Mega X has additionally been upgraded to use multiple computing cores for many molecular evolutionary analyses. Mega X is available in two interfaces (graphical and command line) and can be downloaded from www.megasoftware.net free of charge.

Feasibility study for mega-electron-volt electron beam tomography.

Science.gov (United States)

Hampel, U; Bärtling, Y; Hoppe, D; Kuksanov, N; Fadeev, S; Salimov, R

2012-09-01

Electron beam tomography is a promising imaging modality for the study of fast technical processes. But for many technical objects of interest x rays of several hundreds of keV energy are required to achieve sufficient material penetration. In this article we report on a feasibility study for fast electron beam computed tomography with a 1 MeV electron beam. The experimental setup comprises an electrostatic accelerator with beam optics, transmission target, and a single x-ray detector. We employed an inverse fan-beam tomography approach with radiographic projections being generated from the linearly moving x-ray source. Angular projections were obtained by rotating the object.

Open-Access Mega-Journals: A Bibliometric Profile.

Science.gov (United States)

Wakeling, Simon; Willett, Peter; Creaser, Claire; Fry, Jenny; Pinfield, Stephen; Spezi, Valérie

2016-01-01

In this paper we present the first comprehensive bibliometric analysis of eleven open-access mega-journals (OAMJs). OAMJs are a relatively recent phenomenon, and have been characterised as having four key characteristics: large size; broad disciplinary scope; a Gold-OA business model; and a peer-review policy that seeks to determine only the scientific soundness of the research rather than evaluate the novelty or significance of the work. Our investigation focuses on four key modes of analysis: journal outputs (the number of articles published and changes in output over time); OAMJ author characteristics (nationalities and institutional affiliations); subject areas (the disciplinary scope of OAMJs, and variations in sub-disciplinary output); and citation profiles (the citation distributions of each OAMJ, and the impact of citing journals). We found that while the total output of the eleven mega-journals grew by 14.9% between 2014 and 2015, this growth is largely attributable to the increased output of Scientific Reports and Medicine. We also found substantial variation in the geographical distribution of authors. Several journals have a relatively high proportion of Chinese authors, and we suggest this may be linked to these journals' high Journal Impact Factors (JIFs). The mega-journals were also found to vary in subject scope, with several journals publishing disproportionately high numbers of articles in certain sub-disciplines. Our citation analsysis offers support for Björk & Catani's suggestion that OAMJs's citation distributions can be similar to those of traditional journals, while noting considerable variation in citation rates across the eleven titles. We conclude that while the OAMJ term is useful as a means of grouping journals which share a set of key characteristics, there is no such thing as a "typical" mega-journal, and we suggest several areas for additional research that might help us better understand the current and future role of OAMJs in

Digital DC beam current measurement on SSRF storage ring

International Nuclear Information System (INIS)

Xiong Liang; Yin Chongxian; Liu Ming; Chen Jianfeng

2011-01-01

Both DC current transformer (DCCT) and integrating current transformer (ICT) can be used in DC beam current measurement. The ICT has strong capability of resisting electromagnetic interference, but its measurement accuracy cannot satisfy the DC beam current measurement requirement when using traditional high speed A/D. With high resolution A/D and equivalent sampling system, DC beam current measuring system based on ICT can reach high accuracy compared with DCCT system. In this paper, the ICT-based DC beam current measurement, equivalent sampling method and testing results at Shanghai Synchrotron Radiation Facility(SSRF) is described. (authors)

Beam current monitors in the NLCTA

International Nuclear Information System (INIS)

Nantista, C.; Adolphsen, C.

1997-05-01

The current profile along the 126 ns, multi-bunch beam pulse in the Next Linear Collider Test Accelerator (NLCTA) is monitored with fast toroids (rise time ∼ 1 ns). Inserted at several positions along the beam line, they allow one to track current transmission as a function of position along the bunch train. Various measurements, such as rise time, current, width, and slope, are made on the digitized signals, which can be corrected in software by means of stored frequency response files. The design and implementation of these devices is described

Characterisation Of The Beam Plasma In High Current, Low Energy Ion Beams For Implanters

International Nuclear Information System (INIS)

Fiala, J.; Armour, D. G.; Berg, J. A. van der; Holmes, A. J. T.; Goldberg, R. D.; Collart, E. H. J.

2006-01-01

The effective transport of high current, positive ion beams at low energies in ion implanters requires the a high level of space charge compensation. The self-induced or forced introduction of electrons is known to result in the creation of a so-called beam plasma through which the beam propagates. Despite the ability of beams at energies above about 3-5 keV to create their own neutralising plasmas and the development of highly effective, plasma based neutralising systems for low energy beams, very little is known about the nature of beam plasmas and how their characteristics and capabilities depend on beam current, beam energy and beamline pressure. These issues have been addressed in a detailed scanning Langmuir probe study of the plasmas created in beams passing through the post-analysis section of a commercial, high current ion implanter. Combined with Faraday cup measurements of the rate of loss of beam current in the same region due to charge exchange and scattering collisions, the probe data have provided a valuable insight into the nature of the slow ion and electron production and loss processes. Two distinct electron energy distribution functions are observed with electron temperatures ≥ 25 V and around 1 eV. The fast electrons observed must be produced in their energetic state. By studying the properties of the beam plasma as a function of the beam and beamline parameters, information on the ways in which the plasma and the beam interact to reduce beam blow-up and retain a stable plasma has been obtained

Bipolar power sources for the correction magnets of AmPS

International Nuclear Information System (INIS)

Es, J.T. van; Luigjes, G.; Trigt, J.H. van.

1992-01-01

AmPS consists of many correction magnets which must provide the currents. These currents serve continuously between -3 Amp and +3 Amp. The adjusted current must be stable inside 0,1%. The copper resistance of magnet coils and their wires are ≤ 8 ohm and the self induction is 200 mH. An extended market research on power supplies has enabled the authors to decide to develop it themselves. This development has led to a module system with Bitbus control. (authors). 14 figs., 4 tabs

Electron-Beam Produced Air Plasma: Optical Measurement of Beam Current

Science.gov (United States)

Vidmar, Robert; Stalder, Kenneth; Seeley, Megan

2006-10-01

Experiments to quantify the electron beam current and distribution of beam current in air plasma are discussed. The air plasma is produced by a 100-keV 10-mA electron beam source that traverses a transmission window into a chamber with air as a target gas. Air pressure is between 1 mTorr and 760 Torr. Strong optical emissions due to electron impact ionization are observed for the N2 2^nd positive line at 337.1 nm and the N2^+ 1^st negative line at 391.4 nm. Calibration of optical emissions using signals from the isolated transmission window and a Faraday plate are discussed. The calibrated optical system is then used to quantify the electron distribution in the air plasma.

In Vivo Cardiovascular Pharmacology of 2′,3′-cAMP, 2′-AMP, and 3′-AMP in the Rat

Science.gov (United States)

Mi, Zaichuan

2013-01-01

The naturally occurring purine 2′,3′-cAMP is metabolized in vitro to 2′-AMP and 3′-AMP, which are subsequently metabolized to adenosine. Whether in vivo 2′,3′-cAMP, 2′-AMP, or 3′-AMP are rapidly converted to adenosine and exert rapid effects via adenosine receptors is unknown. To address this question, we compared the cardiovascular and renal effects of 2′,3′-cAMP, 2′-AMP, 3′-AMP, 3′,5′-cAMP, 5′-AMP, and adenosine in vivo in the rat. Purines were infused intravenously while monitoring mean arterial blood pressure (MABP), heart rate (HR), cardiac output, and renal and mesenteric blood flows. Total peripheral (TPR), renal vascular (RVR), and mesenteric vascular (MVR) resistances were calculated. Urine was collected for determination of urine excretion rate [urine volume (UV)]. When sufficient urine was available, the sodium excretion rate (Na+ER) and glomerular filtration rate (GFR) were determined. 2′,3′-cAMP, 2′-AMP, and 3′-AMP dose-dependently and profoundly reduced MABP, HR, TPR, and MVR with efficacy and potency similar to adenosine and 5′-AMP. These effects of 2′,3′-cAMP, 2′-AMP, and 3′-AMP were attenuated by blockade of adenosine receptors with 1,3-dipropyl-8-(p-sulfophenyl)xanthine. 2′,3′-cAMP, 2′-AMP, 3′-AMP, adenosine, and 5′-AMP variably affected RVR, but profoundly (nearly 100%) decreased UV at higher doses. GFR and Na+ER could be measured at the lower doses and were suppressed by 2′,3′-cAMP, 2′-AMP, and 3′-AMP, but not by adenosine or 5′-AMP. 2′,3′-cAMP increased urinary excretion rates of 2′-AMP, 3′-AMP, and adenosine. 3′,5′-cAMP exerted no adverse hemodynamic effects yet increased urinary adenosine as efficiently as 2′,3′-cAMP. Conclusions: In vivo 2′,3′-cAMP is rapidly converted to adenosine. Because both cAMPs increase adenosine in the urinary compartment, these agents may provide unique therapeutic opportunities. PMID:23759508

Ponderomotive enhancement of charged particle beam limiting current

International Nuclear Information System (INIS)

Grebogi, C.; Uhm, H.S.

1987-01-01

The space charge limiting current problem is investigated for a magnetized particle beam propagating in a cylindrical drift tube and in presence of a waveguide mode. It is shown that with a proper choice of a waveguide mode, the limiting current can be greatly enhanced due to ponderomotive effects. Physically, this is accomplished by using the ponderomotive energy to reduce the potential depression due to the beam's self space charge field. Formulas for the limiting current as a function of beam energy and waveguide r.f. field for solid and hollow beams are derived. It is found from these formulas that, in appropriate parameter regimes, the space charge limiting current, say, of a 250kV bem can be enhanced by 70%

Neutral beam current drive scaling in DIII-D

International Nuclear Information System (INIS)

Porter, G.D.; Bhadra, D.K.; Burrell, K.H.

1989-03-01

Neutral beam current drive scaling experiments have been carried out on the DIII-D tokamak at General Atomics. These experiments were performed using up to 10 MW of 80 keV hydrogen beams. Previous current drive experiments on DIII-D have demonstrated beam driven currents up to 340 kA. In the experiments reported here we achieved beam driven currents of at least 500 kA, and have obtained operation with record values of poloidal beta (εβ/sub p/ = 1.4). The beam driven current reported here is obtained from the total plasma current by subtracting an estimate of the residual Ohmic current determined from the measured loop voltage. In this report we discuss the scaling of the current drive efficiency with plasma conditions. Using hydrogen neutral beams, we find the current drive efficiency is similar in Deuterium and Helium target plasmas. Experiments have been performed with plasma electron temperatures up to T/sub e/ = 3 keV, and densities in the range 2 /times/ 10 19 m/sup /minus/3/ 19 m/sup /minus/3/. The current drive efficiency (nIR/P) is observed to scale linearly with the energy confinement time on DIII-D to a maximum of 0.05 /times/ 10 20 m/sup /minus/2/ A/W. The measured efficiency is consistent with a 0-D theoretical model. In addition to comparison with this simple model, detailed analysis of several shots using the time dependent transport code ONETWO is discussed. This analysis indicates that bootstrap current contributes approximately 10--20% of the the total current. Our estimates of this effect are somewhat uncertain due to limited measurements of the radial profile of the density and temperatures. 4 refs., 1 fig., 1 tab

High current beam transport experiments at GSI

International Nuclear Information System (INIS)

Klabunde, J.; Schonlein, A.; Spadtke, P.

1985-01-01

The status of the high current ion beam transport experiment is reported. 190 keV Ar 1+ ions were injected into six periods of a magnetic quadrupole channel. Since the pulse length is > 0.5 ms partial space charge neutralization occurs. In our experiments, the behavior of unneutralized and partially space charge compensated beams is compared. With an unneutralized beam, emittance growth has been measured for high intensities even in case of the zero-current phase advance sigma 0 0 . This initial emittance growth at high tune depression we attribute to the homogenization effect of the space charge density. An analytical formula based on this assumption describes the emittance growth very well. Furthermore the predicted envelope instabilities for sigma 0 > 90 0 were observed even after 6 periods. In agreement with the theory, unstable beam transport was also experimentally found if a beam with different emittances in the two transverse phase planes was injected into the transport channel. Although the space charge force is reduced for a partially neutralized beam a deterioration of the beam quality was measured in a certain range of beam parameters. Only in the range where an unneutralized beam shows the initial emittance growth, the partial neutralization reduces this effect, otherwise the partially neutralized beam is more unstable

Microfabricated Ion Beam Drivers for Magnetized Target Fusion

Science.gov (United States)

Persaud, Arun; Seidl, Peter; Ji, Qing; Ardanuc, Serhan; Miller, Joseph; Lal, Amit; Schenkel, Thomas

2015-11-01

Efficient, low-cost drivers are important for Magnetized Target Fusion (MTF). Ion beams offer a high degree of control to deliver the required mega joules of driver energy for MTF and they can be matched to several types of magnetized fuel targets, including compact toroids and solid targets. We describe an ion beam driver approach based on the MEQALAC concept (Multiple Electrostatic Quadrupole Array Linear Accelerator) with many beamlets in an array of micro-fabricated channels. The channels consist of a lattice of electrostatic quadrupoles (ESQ) for focusing and of radio-frequency (RF) electrodes for ion acceleration. Simulations with particle-in-cell and beam envelope codes predict >10x higher current densities compared to state-of-the-art ion accelerators. This increase results from dividing the total ion beam current up into many beamlets to control space charge forces. Focusing elements can be biased taking advantage of high breakdown electric fields in sub-mm structures formed using MEMS techniques (Micro-Electro-Mechanical Systems). We will present results on ion beam transport and acceleration in MEMS based beamlets. Acknowledgments: This work is supported by the U.S. DOE under Contract No. DE-AC02-05CH11231.

Versatile high current metal ion implantation facility

International Nuclear Information System (INIS)

Brown, I.G.; Dickinson, M.R.; Galvin, J.E.; Godechot, X.; MacGill, R.A.

1992-01-01

A metal ion implantation facility has been developed with which high current beams of practically all the solid metals of the periodic table can be produced. A multicathode, broad-beam, metal vapor vacuum arc ion source is used to produce repetitively pulsed metal ion beams at an extraction voltage of up to 100 kV, corresponding to an ion energy of up to several hundred kiloelectronvolts because of the ion charge state multiplicity, and with a beam current of up to several amps peak pulsed and several tens of milliamps time averaged delivered onto a downstream target. Implantation is done in a broad-beam mode, with a direct line of sight from ion source to target. Here we summarize some of the features of the ion source and the implantation facility that has been built up around it. (orig)

cAMP signalling in the vasculature: the role of Epac (exchange protein directly activated by cAMP).

Science.gov (United States)

Roberts, Owain Llŷr; Dart, Caroline

2014-02-01

The second messenger cAMP plays a central role in mediating vascular smooth muscle relaxation in response to vasoactive transmitters and in strengthening endothelial cell-cell junctions that regulate the movement of solutes, cells and macromolecules between the blood and the surrounding tissue. The vasculature expresses three cAMP effector proteins: PKA (protein kinase A), CNG (cyclic-nucleotide-gated) ion channels, and the most recently discovered Epacs (exchange proteins directly activated by cAMP). Epacs are a family of GEFs (guanine-nucleotide-exchange factors) for the small Ras-related GTPases Rap1 and Rap2, and are being increasingly implicated as important mediators of cAMP signalling, both in their own right and in parallel with the prototypical cAMP target PKA. In the present paper, we review what is currently known about the role of Epac within blood vessels, particularly with regard to the regulation of vascular tone, endothelial barrier function and inflammation.

Governance and institutions of transportation investments in U.S. mega-regions

Directory of Open Access Journals (Sweden)

H. L. Vega

2008-09-01

Full Text Available From a planning perspective, a mega-region can be defined as an extended network of metropolitan centers and their surrounding areas, crossing county and state lines, linked by integrated labor markets, land use systems and transportation and communication infrastructure. From a governance perspective, delimiting the jurisdictional borders of a mega-region is rather challenging due to the overlap of hierarchy of governance systems. It has been suggested that the effective management of existing transportation infrastructure and the planning and financing of new investments in these areas will need to operate under a regional framework of governance. What such regional framework might look like is still subject to debate. Despite years in the planning, currently no mega-regional transportation initiative has been implemented in the U.S. This article uses descriptive and interpretative analysis to further the debate in two areas. It first reviews definitional issues in the existing literature as they apply to mega-regions and transportation. Second, it undertakes a comprehensive survey of regional initiatives, such as the Corridors of the Future Program, to highlight the complexity of multi-state transportation projects. Lessons from this survey can be useful when developing future transport policy, as policymakers increase their efforts to adopt regional governance initiatives to finance transportation investments worldwide.

Current density monitor for intense relativistic electron beams

International Nuclear Information System (INIS)

Fiorito, R.B.; Raleigh, M.; Seltzer, S.M.

1986-01-01

We describe a new type of electric probe which is capable of measuring the time-resolved current density profile of a stable, reproducible, high-energy (>4-MeV) high-current (>1-kA) electron beam. The sensing element of this probe is an open-ended but capped-off 50-Ω coaxial line constructed of graphite. The graphite sensor is 4.3 mm in diameter, 6 cm long, and is range thin to the primary beam electrons. The probe produces a signal proportional to the intercepted beam current. When the sensor is scanned radially through the beam during repeated pulses, a curve of signal versus depth of insertion is produced from which the radial current density profile can be determined. Measurements are presented of the profile of the electron beam from the Experimental Test Accelerator (4.5 MeV, 10 kA) at Lawrence Livermore National Laboratory. Good agreement is shown between measurements made with this probe and the beam radius as predicted by transport codes. The advantage of the electric probe lies in its ruggedness, simplicity, inherent fast rise time, and low cost. In contrast to other systems it requires no radiation shielding, water cooling, or auxiliary support equipment to operate in an intense beam environment

Facilitators and Inhibitors of Bidding and Hosting Mega Sporting Events in Iran

Directory of Open Access Journals (Sweden)

Mohammad Koosha

2013-01-01

Full Text Available Legacies of hosting mega sporting events have been attempting idea for both the developed and the developing nations to participate in "bidding" competitions. Through mega sporting events bid process, despite all defined essentials infrastructures, the viewpoint of local organizing committee play a significant role to propose a winning bid and delivery of successful games. This research aims to identify the facilitators and inhibitors of bidding and hosting mega sporting events in Iran from the viewpoints of the Iranian distinguished professors in the sport management and the sport executive managers. Researcher questionnaire and Semi-structure interviews were conducted to gain in depth data. The results indicated that Iran currently has limitations to have winning bid and successful host mega sporting events; even though, it possesses the potential to do so. Public interest and support for hosting the sport events, good security condition against terrorism and tourist attractions are known as the strong points and he challenges and inhibitors which Iran is faced with includes: the qualitative and quantitative weakness in the transportation infrastructures and sport venues, west countries economic boycott, unstable government support and the lack of long-run planning for the events.

Electron gun for formation of two high-current beams

International Nuclear Information System (INIS)

Borisov, A.R.; Zherlitsyn, A.G.; Mel'nikov, G.V.; Shtejn, Yu.G.

1982-01-01

The design of the ''Tonus'' accelerator electron gun for formation of two high-current beams aiming at the production of the maximum beam power and density is described. The results of investigation of two modes of beam formation are presented. In the first variant the beams were produced by means of two plane diodes with 40 mm diameter cathodes made of stainless steel and anodes made of 50 μm thick titanium foil. In the second variant the beams were formed by means of two coaxial diodes with magnetic insulation. In one diode the cathode diameter equals to 74 mm, the anode diameter - 92 mm, in the other diode 16 and 44 mm respectively. Current redistribution in the diodes and its effect on accelerating voltage are investigated. It is shown that the gun permits formation of synchronized two high-current beams, iaving equal electron energied. Wide range current control of both beams is possible

Nonequivalence of the magnetostatic potential energy corresponding to the Ampère and Grassmann current element force formulas

International Nuclear Information System (INIS)

Minteer, Timothy M

2013-01-01

The equivalence of the Ampère and Grassmann (Biot–Savart/Lorentz) current element force formulas is well established. However, when the magnetostatic potential energy corresponding to these force formulas is evaluated, the formulas are found to be nonequivalent. The historical current element force formulas are first presented. The magnetostatic potential energy corresponding to these historical current element force formulas are then analysed. The end result establishes the Grassmann and Neumann current element force formulas as the only commonly referenced formulas giving the correct magnetostatic potential energy for circuital currents. (paper)

FMIT direct-current beam monitor

International Nuclear Information System (INIS)

Brousseau, A.T.; Chamberlin, D.D.

1981-01-01

The prototype injector section for the Fusion Materials Irradiation Test (FMIT) Facility being developed at the Los Alamos National Laboratory requires that beam parameters be noninterceptively monitored. This report describes the application of a single toroidal core, coupled with very simple circuitry, that results in the production of a simple instrument, and eliminates the problems inherent in the Faraday cup technique for the current measurements of the FMIT injector beam

Aspectos da miocardite em chagásicos crônicos com "megas" e sem "megas" com insuficiência cardíaca congestiva

Directory of Open Access Journals (Sweden)

Hipólito de Oliveira Almeida

1984-06-01

Full Text Available O estudo microscópico de 20 corações de chagásicos com "megas" e de outros 20 sem "megas" com insuficiência cardíaca congestiva (ICC revelou que tanto a Jibrose quanto o exsudato inflamatório no miocárdio são discretos nos casos de "megas" e geralmente acentuados nos casos de ICC. Considerando-se que nos "megas" a ICC, a hipertrofia do miocárdio e a lesão vorticilar são fenômenos raros, nossos achados (atuais e anteriores sugerem que estes estejam relacionados principalmente com a agressão inflamatória ao miocárdio ventricular, uma vez que a desnervação é, geralmente, mais acentuada nos casos de "megas" que nos de ICC.

Narrow linewidth picosecond UV pulsed laser with mega-watt peak power.

Science.gov (United States)

Huang, Chunning; Deibele, Craig; Liu, Yun

2013-04-08

We demonstrate a master oscillator power amplifier (MOPA) burst mode laser system that generates 66 ps/402.5 MHz pulses with mega-watt peak power at 355 nm. The seed laser consists of a single frequency fiber laser (linewidth laser is operating in a 5-μs/10-Hz macropulse mode. The laser output has a transform-limited spectrum with a very narrow linewidth of individual longitudinal modes. The immediate application of the laser system is the laser-assisted hydrogen ion beam stripping for the Spallation Neutron Source (SNS).

High-power optical coatings for a mega-joule class ICF laser

International Nuclear Information System (INIS)

Kozlowski, M.R.; Thomas, I.M.; Campbell, J.H.; Rainer, F.

1992-11-01

As a consequence of advancements in Inertial Confinement Fusion research, LLNL is developing plans for a new 1.5 to 2 mega-joule solid-state Nd:glass laser designed to achieve fusion ignition. The new design is possible in part due to advances in optical coatings suitable for high power laser systems. High damage threshold mirrors and polarizers are comprised of electron beam deposited dielectric multilayers. Subthreshold illumination, or laser conditioning, of the multilayer coatings results in an increase in the damage thresholds by factors of 2 to 3 at 1.06μm, thus meeting the fluence requirements of the advanced architecture. For anti-reflective coatings, protective organic coatings for non-linear crystals and phase plates for beam smoothing, sol-gel films provide high damage thresholds coatings at low cost

On the limiting stationary currents of relativistic electron beams

International Nuclear Information System (INIS)

Kavchuk, V.N.; Kondratenko, A.N.

1987-01-01

The problem on electron beam transport in the system of different configurations both vacuum and filled with gas or plasma is connected with the problem of the limiting current, which can conduct such systems. Two models of a vacuum relativistic electron beam (REB) are considered. It is shown that there is upper limit for the value of the external magnetic field, H 0 , in the model of isovelocity REB with the constant longitudinal beam particle rate, β z =const. Estimation of the limiting current of REB as a series of inverse power H 0 is obtained. Estimations of the limiting current of magnetized hallow REB with thin walls are obtained in another model with β z ≠ const. Determination used in this case of the limiting current is directly connected with ''trapping'' of the beam central part due to formation of a virtual cathode and based on consideration of uniflux electron motion in the beam. Such an approach allows to obtain estimations of the limiting current of the thin-wall hallow beam. In this case an upper limit for the thickness of the beam wall is connected with the bottom limit for the value of the external magnetic field providing radial beam equilibrium

Absolute beam current monitoring in endstation c

International Nuclear Information System (INIS)

Bochna, C.

1995-01-01

The first few experiments at CEBAF require approximately 1% absolute measurements of beam currents expected to range from 10-25μA. This represents errors of 100-250 nA. The initial complement of beam current monitors are of the non intercepting type. CEBAF accelerator division has provided a stripline monitor and a cavity monitor, and the authors have installed an Unser monitor (parametric current transformer or PCT). After calibrating the Unser monitor with a precision current reference, the authors plan to transfer this calibration using CW beam to the stripline monitors and cavity monitors. It is important that this be done fairly rapidly because while the gain of the Unser monitor is quite stable, the offset may drift on the order of .5μA per hour. A summary of what the authors have learned about the linearity, zero drift, and gain drift of each type of current monitor will be presented

Aspectos da miocardite em chagásicos crônicos com "megas" e sem "megas" com insuficiência cardíaca congestiva

OpenAIRE

Almeida,Hipólito de Oliveira; Gobbi,Helenice; Teixeira,Vicente de Paula Antunes; Araújo,Waldir Ferreira; Fernandes,Paula Ávila

1984-01-01

O estudo microscópico de 20 corações de chagásicos com "megas" e de outros 20 sem "megas" com insuficiência cardíaca congestiva (ICC) revelou que tanto a Jibrose quanto o exsudato inflamatório no miocárdio são discretos nos casos de "megas" e geralmente acentuados nos casos de ICC. Considerando-se que nos "megas" a ICC, a hipertrofia do miocárdio e a lesão vorticilar são fenômenos raros, nossos achados (atuais e anteriores) sugerem que estes estejam relacionados principalmente com a agressão ...

Current-Voltage Characteristic of Nanosecond - Duration Relativistic Electron Beam

Science.gov (United States)

Andreev, Andrey

2005-10-01

The pulsed electron-beam accelerator SINUS-6 was used to measure current-voltage characteristic of nanosecond-duration thin annular relativistic electron beam accelerated in vacuum along axis of a smooth uniform metal tube immersed into strong axial magnetic field. Results of these measurements as well as results of computer simulations performed using 3D MAGIC code show that the electron-beam current dependence on the accelerating voltage at the front of the nanosecond-duration pulse is different from the analogical dependence at the flat part of the pulse. In the steady-state (flat) part of the pulse), the measured electron-beam current is close to Fedosov current [1], which is governed by the conservation law of an electron moment flow for any constant voltage. In the non steady-state part (front) of the pulse, the electron-beam current is higher that the appropriate, for a giving voltage, steady-state (Fedosov) current. [1] A. I. Fedosov, E. A. Litvinov, S. Ya. Belomytsev, and S. P. Bugaev, ``Characteristics of electron beam formed in diodes with magnetic insulation,'' Soviet Physics Journal (A translation of Izvestiya VUZ. Fizika), vol. 20, no. 10, October 1977 (April 20, 1978), pp.1367-1368.

AMP is an adenosine A1 receptor agonist.

Science.gov (United States)

Rittiner, Joseph E; Korboukh, Ilia; Hull-Ryde, Emily A; Jin, Jian; Janzen, William P; Frye, Stephen V; Zylka, Mark J

2012-02-17

Numerous receptors for ATP, ADP, and adenosine exist; however, it is currently unknown whether a receptor for the related nucleotide adenosine 5'-monophosphate (AMP) exists. Using a novel cell-based assay to visualize adenosine receptor activation in real time, we found that AMP and a non-hydrolyzable AMP analog (deoxyadenosine 5'-monophosphonate, ACP) directly activated the adenosine A(1) receptor (A(1)R). In contrast, AMP only activated the adenosine A(2B) receptor (A(2B)R) after hydrolysis to adenosine by ecto-5'-nucleotidase (NT5E, CD73) or prostatic acid phosphatase (PAP, ACPP). Adenosine and AMP were equipotent human A(1)R agonists in our real-time assay and in a cAMP accumulation assay. ACP also depressed cAMP levels in mouse cortical neurons through activation of endogenous A(1)R. Non-selective purinergic receptor antagonists (pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid and suramin) did not block adenosine- or AMP-evoked activation. Moreover, mutation of His-251 in the human A(1)R ligand binding pocket reduced AMP potency without affecting adenosine potency. In contrast, mutation of a different binding pocket residue (His-278) eliminated responses to AMP and to adenosine. Taken together, our study indicates that the physiologically relevant nucleotide AMP is a full agonist of A(1)R. In addition, our study suggests that some of the physiological effects of AMP may be direct, and not indirect through ectonucleotidases that hydrolyze this nucleotide to adenosine.

Noise reduction in the beam current monitor

International Nuclear Information System (INIS)

Arai, Shigeaki.

1982-02-01

A simple noise reduction system using a pulse transformer and a pair of L C low pass filters has been introduced to the beam current monitor of a current transformer type at the INS electron linac. With this system, the pick-up noise has been reduced to be 1% of the noise without noise reduction. Signal deformation caused by this system is relatively small and the beam current pulse down to 20 mA is successfully monitored in the actual accelerator operation. (author)

Bootstrap current of fast ions in neutral beam injection heating

International Nuclear Information System (INIS)

Huang Qianhong; Gong Xueyu; Yang Lei; Li Xinxia; Lu Xingqiang; Yu Jun

2012-01-01

The bootstrap current of fast ions produced by the neutral beam injection is investigated in a large aspect ratio tokamak with circular cross-section under specific parameters. The bootstrap current density distribution and the total bootstrap current are figured out. In addition, the beam bootstrap current always accompanies the electron return current due to the parallel momentum transfer from fast ions. With the electron return current considered, the net current density obviously decreases due to electron return current, at the same time the peak of current moves towards the centre plasma. Numerical results show that the value of the net current depends sensitively not only on the angle of the neutral beam injection but also on the ratio of the velocity of fast ions to the critical velocity: the value of net current is small for the neutral beam parallel injection but increases multipliedly for perpendicular injection, and increases with beam energy increasing. (authors)

Upgrade of the TAMU MDM-focal plane detector with MicroMegas technology

Energy Technology Data Exchange (ETDEWEB)

Spiridon, A., E-mail: aspiridon@comp.tamu.edu [Cyclotron Institute, Texas A& M University, College Station, TX 77843 (United States); Pollacco, E. [IRFU, CEA Saclay, Gif-sur-Yvette (France); Roeder, B.T.; Saastamoinen, A.; Chyzh, R.; Dag, M.; Tribble, R.E. [Cyclotron Institute, Texas A& M University, College Station, TX 77843 (United States); Trache, L.; Pascovici, G. [National Institute of Physics and Nuclear Engineering, Bucharest-Magurele RO-077125 (Romania); De Oliveira, R. [CERN, Geneva (Switzerland)

2016-06-01

A gridded ionization chamber used as a focal plane detector at the back of the TAMU-MDM spectrometer was modified to use MicroMegas technology for the purpose of improving energy resolution and particle identification. The upgraded system was tested in experimental conditions with several heavy-ion beams at 12 MeV/u and found to achieve resolutions between 3.2% and 4.8%. This is a significant improvement over the previous performance of 10–15% obtained using the existing, conventional ionization chambers.

Upgrade of the TAMU MDM-focal plane detector with MicroMegas technology

International Nuclear Information System (INIS)

Spiridon, A.; Pollacco, E.; Roeder, B.T.; Saastamoinen, A.; Chyzh, R.; Dag, M.; Tribble, R.E.; Trache, L.; Pascovici, G.; De Oliveira, R.

2016-01-01

A gridded ionization chamber used as a focal plane detector at the back of the TAMU-MDM spectrometer was modified to use MicroMegas technology for the purpose of improving energy resolution and particle identification. The upgraded system was tested in experimental conditions with several heavy-ion beams at 12 MeV/u and found to achieve resolutions between 3.2% and 4.8%. This is a significant improvement over the previous performance of 10–15% obtained using the existing, conventional ionization chambers.

Controlling hollow relativistic electron beam orbits with an inductive current divider

Energy Technology Data Exchange (ETDEWEB)

Swanekamp, S. B.; Richardson, A. S.; Angus, J. R.; Cooperstein, G.; Hinshelwood, D. D.; Ottinger, P. F.; Rittersdorf, I. M.; Schumer, J. W.; Weber, B. V.; Zier, J. C. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States)

2015-02-15

A passive method for controlling the trajectory of an intense, hollow electron beam is proposed using a vacuum structure that inductively splits the beam's return current. A central post carries a portion of the return current (I{sub 1}), while the outer conductor carries the remainder (I{sub 2}). An envelope equation appropriate for a hollow electron beam is derived and applied to the current divider. The force on the beam trajectory is shown to be proportional to (I{sub 2}-I{sub 1}), while the average force on the envelope (the beam width) is proportional to the beam current I{sub b} = (I{sub 2} + I{sub 1}). The values of I{sub 1} and I{sub 2} depend on the inductances in the return-current path geometries. Proper choice of the return-current geometries determines these inductances and offers control over the beam trajectory. Solutions using realistic beam parameters show that, for appropriate choices of the return-current-path geometry, the inductive current divider can produce a beam that is both pinched and straightened so that it approaches a target at near-normal incidence with a beam diameter that is on the order of a few mm.

Neutral beam current drive with balanced injection

International Nuclear Information System (INIS)

Eckhartt, D.

1990-01-01

Current drive with fast ions has proved its capability to sustain a tokamak plasma free of externally induced electric fields in a stationary state. The suprathermal ion population within the toroidal plasma was created by quasi-tangential and uni-directional injection of high-energy neutral atoms, their ionisation and subsequent deceleration by collisions with the background plasma particles. In future large tokamaks of the NET/INTER-type, with reactor-relevant values of plasma density and temperature, this current drive scheme is expected to maintain the toroidal current at the plasma centre, as current drive by lower hybrid waves will be restricted to the outer plasma regions owing to strong wave damping. Adequate penetration of the neutral atoms through the dense plasma requires particle energies of several hundred kilovolts per nucleon since beam absorption scales roughly with the ratio beam energy over density. The realisation of such high-energy high-power neutral beams, based on negative ion technology, is now under study. (author) 7 refs., 2 figs

AMP Is an Adenosine A1 Receptor Agonist*

Science.gov (United States)

Rittiner, Joseph E.; Korboukh, Ilia; Hull-Ryde, Emily A.; Jin, Jian; Janzen, William P.; Frye, Stephen V.; Zylka, Mark J.

2012-01-01

Numerous receptors for ATP, ADP, and adenosine exist; however, it is currently unknown whether a receptor for the related nucleotide adenosine 5′-monophosphate (AMP) exists. Using a novel cell-based assay to visualize adenosine receptor activation in real time, we found that AMP and a non-hydrolyzable AMP analog (deoxyadenosine 5′-monophosphonate, ACP) directly activated the adenosine A1 receptor (A1R). In contrast, AMP only activated the adenosine A2B receptor (A2BR) after hydrolysis to adenosine by ecto-5′-nucleotidase (NT5E, CD73) or prostatic acid phosphatase (PAP, ACPP). Adenosine and AMP were equipotent human A1R agonists in our real-time assay and in a cAMP accumulation assay. ACP also depressed cAMP levels in mouse cortical neurons through activation of endogenous A1R. Non-selective purinergic receptor antagonists (pyridoxalphosphate-6-azophenyl-2′,4′-disulfonic acid and suramin) did not block adenosine- or AMP-evoked activation. Moreover, mutation of His-251 in the human A1R ligand binding pocket reduced AMP potency without affecting adenosine potency. In contrast, mutation of a different binding pocket residue (His-278) eliminated responses to AMP and to adenosine. Taken together, our study indicates that the physiologically relevant nucleotide AMP is a full agonist of A1R. In addition, our study suggests that some of the physiological effects of AMP may be direct, and not indirect through ectonucleotidases that hydrolyze this nucleotide to adenosine. PMID:22215671

The Bootstrap Current and Neutral Beam Current Drive in DIII-D

International Nuclear Information System (INIS)

Politzer, P.A.

2005-01-01

Noninductive current drive is an essential part of the implementation of the DIII-D Advanced Tokamak program. For an efficient steady-state tokamak reactor, the plasma must provide close to 100% bootstrap fraction (f bs ). For noninductive operation of DIII-D, current drive by injection of energetic neutral beams [neutral beam current drive (NBCD)] is also important. DIII-D experiments have reached ∼80% bootstrap current in stationary discharges without inductive current drive. The remaining current is ∼20% NBCD. This is achieved at β N [approximately equal to] β p > 3, but at relatively high q 95 (∼10). In lower q 95 Advanced Tokamak plasmas, f bs ∼ 0.6 has been reached in essentially noninductive plasmas. The phenomenology of high β p and β N plasmas without current control is being studied. These plasmas display a relaxation oscillation involving repetitive formation and collapse of an internal transport barrier. The frequency and severity of these events increase with increasing β, limiting the achievable average β and causing modulation of the total current as well as the pressure. Modeling of both bootstrap and NBCD currents is based on neoclassical theory. Measurements of the total bootstrap and NBCD current agree with calculations. A recent experiment based on the evolution of the transient voltage profile after an L-H transition shows that the more recent bootstrap current models accurately describe the plasma behavior. The profiles and the parametric dependences of the local neutral beam-driven current density have not yet been compared with theory

Fast Beam Current Change Monitor for the LHC

CERN Document Server

Kral, Jan

Stringent demands on the LHC safety and protection systems require improved methods of detecting fast beam losses. The Fast Beam Current Transformer (FBCT) is a measurement instrument, providing information about bunch-to-bunch intensity of the accelerated beam. This thesis describes the development of a new protection system based on the FBCT signal measurements. This system, the Fast Beam Current Change Monitor (FBCCM), measures the FBCT signal in a narrow frequency band and computes time derivation of the beam signal magnitude. This derivation is proportional to the beam losses. When the losses exceed a certain level, the FBCCM requests a beam dump in order to protect the LHC. The LHC protection will be ensured by four FBCCMs which will be installed into the LHC in July 2014. Six FBCCMs have been already constructed and their characteristics were measured with satisfactory results. The FBCCMs were tested by a laboratory simulation of the real LHC environment.

High-energy tritium beams as current drivers in tokamak reactors

International Nuclear Information System (INIS)

Mikkelsen, D.R.; Grisham, L.R.

1983-04-01

The effect on neutral-beam design and reactor performance of using high-energy (approx. 3-10 MeV) tritium neutral beams to drive steady-state tokamak reactors is considered. The lower current of such beams leads to several advantages over lower-energy neutral beams. The major disadvantage is the reduction of the reactor output caused by the lower current-drive efficiency of the high-energy beams

Competitive cAMP Antagonists for cAMP-Receptor Proteins

NARCIS (Netherlands)

Haastert, Peter J.M. van; Driel, Roel van; Jastorff, Bernd; Baraniak, Janina; Stec, Wojciech J.; Wit, René J.W. de

1984-01-01

The two exocyclic oxygen atoms at phosphorus of cAMP have been replaced by a sulfur atom or by a dimethylamino group. These substitutions introduce chirality at the phosphorus atom; therefore, two diastereoisomers are known for each derivative: (SP)-cAMPS, (RP)-cAMPS, (SP)-cAMPN(CH3)2, and

Analysis of Biot-Savart’s law in comparison with Ampère’s force between current elements

Directory of Open Access Journals (Sweden)

Hugo Shigueo Tanaka dos Santos

2017-12-01

Full Text Available Nowadays, we use Biot-Savart’s Law and Grassmann’s force to study the magnetic fields effects. We can observe that this force apparently do not always satisfy the principle of action and reaction. In contrast, Ampère’s force always satisfies this principle explicitly and always along the straight line connecting the two currents elements. The present work presents a historic analysis of the development of these two forces, which have been developed based on interpretations of the Ørsted’s experiment. We also compare these two forces in order to verify if both have the same result. We show that the Grassmann’s expression, in fact, does not satisfy to the principle of action and reaction. Ampère’s force not only follows the principle of action and reaction in the strongest way, but it also explains the phenomena based action at a distance, which is easier to be observed and has many other powerful results, not only in the electromagnetism. In order to compare these two approaches, we calculate the force that an infinite rectilinear wire exerts on a loop of conductive material, both with current.

Sistem Keamanan Pintu Berbasis Arduino Mega

Directory of Open Access Journals (Sweden)

Akbar iskandar

2017-12-01

Full Text Available Abstract  : This study aims is to 1 design prototype security room lecturer room based arduino mega integrated with Fingerprint and camera, 2 Testing the effectiveness of prototype security room door lecturer. This type of research is a type of research design that is within the scope of research R & D (Research and Development. Data were collected based on observations and interviews. Data analysis technique by descriptive method. The result of the research shows that prototype of latchroom room door STMIK AKBA using arduino mega camera and fingerprint can assist lecturers in improving security in lecturers room and based on descriptive analysis result found that the device can run effectively. Abstrak: Penelitian ini bertujuan adalah untuk 1 merancang prototype pengamanan pintu ruang dosen berbasis arduino mega yang terintegrasi dengan Fingerprint dan kamera, 2 Menguji Efektifitas prototype kemanan pintu ruang dosen. Jenis penelitian ini adalah jenis penelitian perancangan yang dalam lingkup penelitian R&D (Penelitian dan Pengembangan. Data dikumpulkan berdasarkan observasi dan wawancara. Teknik analisis data dengan cara deskriptif. Hasil penelitian itu menunjukkan bahwa prototype pengaman pintu ruang dosen STMIK AKBA menggunakan kamera dan fingerprint berbasis arduino mega dapat membantu dosen dalam meningkatkan keamanan pada ruang dosen dan berdasarkan hasil analisis secara deskriptif ditemukan bahwa perangkat tersebut dapat berjalan dengan efektif.

Control of renin secretion from rat juxtaglomerular cells by cAMP-specific phosphodiesterases

DEFF Research Database (Denmark)

Friis, Ulla G; Jensen, Boye L; Sethi, Shala

2002-01-01

, and the PDE4 inhibitor rolipram enhanced cellular cAMP content. Dialysis of single JG cells with cAMP in whole-cell patch-clamp experiments led to concentration-dependent, biphasic changes in cell membrane capacitance (C(m)) with a marked increase in C(m) at 1 micromol/L, no net change at 10 micromol....../L, and a decrease at 100 micromol/L cAMP. cGMP also had a dual effect on C(m) at 10-fold higher concentration compared with cAMP. Trequinsin, milrinone, and rolipram mimicked the effect of cAMP on C(m). Trequinsin, cAMP, and cGMP enhanced outward current 2- to 3-fold at positive membrane potentials. The effects...... of cAMP, cGMP, and trequinsin on C(m) and cell currents were abolished by inhibition of protein kinase A with Rp-cAMPs. We conclude that degradation of cAMP by PDE3 and PDE4 contributes to regulation of renin release from JG cells. Our data provide evidence at the cellular level that stimulation...

Bootstrap current of fast ions in neutral beam injection heating

International Nuclear Information System (INIS)

Huang Qianhong; Gong Xueyu; Li Xinxia; Yu Jun

2012-01-01

The bootstrap current of fast ions produced by neutral beam injection (NBI) is investigated in a large-aspect-ratio tokamak with circular cross-section under specific parameters. The bootstrap current density distribution and the total bootstrap current are reported. In addition, the beam bootstrap current always accompanies the electron return current due to the parallel momentum transfer from fast ions. With the electron return current taken into consideration, the net current density obviously decreases; at the same time, the peak of the current moves towards the central plasma. Numerical results show that the value of the net current depends sensitively not only on the angle of the NBI but also on the ratio of the velocity of fast ions to the critical velocity: the value of the net current is small for neutral beam parallel injection, but increases severalfold for perpendicular injection, and increases with increasing beam energy. (paper)

The development of beam current monitors in the APS

International Nuclear Information System (INIS)

Wang, X.; Lenkszus, F.; Rotela, E.

1995-01-01

The Advanced Photon Source (APS) is a third-generation 7-GeV synchrotron radiation source. The precision measurement of beam current is a challenging task in high energy accelerators, such as the APS, with a wide range of beam parameters and complicated noise, radiation, and thermal environments. The beam pulses in the APS injector and storage ring have charge ranging from 50pC to 25nC with pulse durations varying from 30ps to 30ns. A total of nine non- intercepting beam current monitors have been installed in the APS facility (excluding those in the linac) for general current measurement. In addition, several independent current monitors with specially designed redundant interlock electronics are installed for personnel safety and machine protection. This paper documents the design and development of current monitors in the APS,. discusses the commissioning experience in the past year, and presents the results of recent operations

A socio-ecological adaptive approach to contaminated mega-site management: From 'control and correct' to 'coping with change'

Science.gov (United States)

Schirmer, Mario; Lyon, Ken; Armstrong, James E.; Farrell, Katharine N.

2012-01-01

Mega-sites have a notable impact on surrounding ecological systems. At such sites there are substantial risks associated with complex socio-ecological interactions that are hard to characterize, let alone model and predict. While the urge to control and clean-up mega-sites (control and correct) is understandable, rather than setting a goal of cleaning up such sites, we suggest a more realistic response strategy is to address these massive and persistent sources of contamination by acknowledging their position as new features of the socio-ecological landscapes within which they are located. As it seems nearly impossible to clean up such sites, we argue for consideration of a 'coping with change' rather than a 'control and correct' approach. This strategy recognizes that the current management option for a mega-site, in light of its physical complexities and due to changing societal preferences, geochemical transformations, hydrogeology knowledge and remedial technology options may not remain optimal in future, and therefore needs to be continuously adapted, as community, ecology, technology and understanding change over time. This approach creates an opportunity to consider the relationship between a mega-site and its human and ecological environments in a different and more dynamic way. Our proposed approach relies on iterative adaptive management to incorporate mega-site management into the overall socio-ecological systems of the site's context. This approach effectively embeds mega-site management planning in a triple bottom line and environmental sustainability structure, rather than simply using single measures of success, such as contaminant-based guidelines. Recognizing that there is probably no best solution for managing a mega-site, we present a starting point for engaging constructively with this seemingly intractable issue. Therefore, we aim to initiate discussion about a new approach to mega-site management, in which the complexity of the problems posed

Microstructure cantilever beam for current measurement

Directory of Open Access Journals (Sweden)

M.T.E. Khan

2010-01-01

Full Text Available Most microelectromechanical systems (MEMS sensors are based on the microcantilever technology, which uses a broad range of design materials and structures. The benefit ofMEMStechnology is in developing devices with a lower cost, lower power consumption, higher performance and greater integration. A free-end cantilever beam with a magnetic material mass has been designed using MEMS software tools. The magnetic material was used to improve the sensitivity of the cantilever beam to an externally-applied magnetic field. The cantilever was designed to form a capacitance transducer, which consisted of variable capacitance where electrical and mechanical energies were exchanged. The aim of this paper was to analyse the system design of the microcantilever when subjected to a magnetic field produced by a current-carrying conductor. When the signal, a sinusoidal current with a constant frequency, was applied, the cantilever beam exhibited a vibration motion along the vertical axis when placed closer to the line current. This motion created corresponding capacitance changes and generated a voltage output proportional to the capacitive change in the signal-processing circuitry attached to the microcantilever. The equivalent massspring system theory was used to describe and analyse the effect of the natural frequency of the system vibrations and motion due to the applied magnetic field, in a single-degree of freedom. The main application of this microcantilever is in current measurements to develop a non-contact current sensor mote.

Beam position and total current monitor for heavy ion fusion beams

International Nuclear Information System (INIS)

Berners, D.; Reginato, L.L.

1992-10-01

Heavy Ion Fusion requires moderate currents, 1-10A, for a duration of about 1 μs. For accurate beam transport, the center of charge must be located to within ± 100 μm. Beam position and intensity may be excited at frequencies approaching 10 MHz, and the monitoring system must have adequate bandwidth to respond at these frequencies. We have modified the Rogowski technique by using distributed reactance multiturn magnetic loops so that it is suitable for measuring current position as well as amplitude. Four identical stripline coils are wound one per quadrant around a non magnetic core. The sensitivity is similar to that of a lumped coil system, with the added advantage of increased bandwidth. The voltages induced on the four separate coils are compared and suitable signal conditioning is performed to recover beam position and intensity information

Cryogenic current comparators for precise ion beam current measurements

International Nuclear Information System (INIS)

Kurian, Febin

2015-01-01

The planned Facility for Antiproton and Ion Research (FAIR) at GSI has to cope with a wide range of beam intensities in its high-energy beam transport systems and in the storage rings. To meet the requirements of a non-intercepting intensity measurement down to nA range, it is planned to install a number of Cryogenic Current Comparator (CCC) units at different locations in the FAIR beamlines. In this work, the first CCC system for intensity measurement of heavy ion beams, which was developed at GSI, was re-commissioned and upgraded to be used as a 'GSI - CCC prototype' for extensive optimization and development of an improved CCC for FAIR. After installation of a new SQUID sensor and related electronics, as well as implementation of improved data acquisition components, successful beam current measurements were performed at a SIS18 extraction line. The measured intensity values were compared with those of a Secondary Electron Monitor (SEM). Furthermore, the spill-structure of a slowly extracted beam was measured and analyzed, investigating its improvement due to bunching during the slow-extraction process. Due to the extreme sensitivity of the superconducting sensor, the determined intensity values as well as the adjustment of the system for optimal performance are strongly influenced by the numerous noise sources of the accelerators environment. For this reason, detailed studies of different effects caused by noise have been carried out, which are presented together with proposals to reduce them. Similarly, studies were performed to increase the dynamic range and overcome slew rate limitations, the results of which are illustrated and discussed as well. By combining the various optimizations and characterizations of the GSI CCC prototype with the experiences made during beam operation, criteria for a more efficient CCC System could be worked out, which are presented in this work. The details of this new design are worked out with respect to the

Development of an external Faraday cup for beam current measurements

International Nuclear Information System (INIS)

Kim, Kye-Ryung; Jung, Myung-Hwan; Ra, Se-Jin; Lee, Seok-Ki

2010-01-01

In general, beam current measurements are very important for many kinds of experiments using highly energetic particle beams at accelerators, such as cyclotrons, linacs, etc. The Faraday cup is known to be one of the most popular beam current measurement tools. We developed an external Faraday cup to measure the beam current at a dedicated beam line for low-flux experiments installed at the MC-50 cyclotron of Korea Institute of Radiological and Medical Sciences (KIRAMS). It was designed for external beam current measurements and is composed of a vacuum chamber, an entrance window, a collimator, a electrostatic suppressor ring, and a cup. The window is made of 75-um-thick Kapton film, and the diameter of the collimator is 10 mm or 20 mm. The ring and the cup has 5-cm inner diameters, and the thickness of the bottom of the cup is 2 cm, which is enough to absorb the total proton energy up to 45 MeV. Using this external Faraday cup, we measured the beam current from the cyclotron, and we compared measured flux to the results from film dosimetry using GAF films.

Beam brilliance investigation of high current ion beams at GSI heavy ion accelerator facility.

Science.gov (United States)

Adonin, A A; Hollinger, R

2014-02-01

In this work the emittance measurements of high current Ta-beam provided by VARIS (Vacuum Arc Ion Source) ion source are presented. Beam brilliance as a function of beam aperture at various extraction conditions is investigated. Influence of electrostatic ion beam compression in post acceleration gap on the beam quality is discussed. Use of different extraction systems (single aperture, 7 holes, and 13 holes) in order to achieve more peaked beam core is considered. The possible ways to increase the beam brilliance are discussed.

High-current Standing Wave Linac With Gyrocon Power Source

CERN Document Server

Karliner, M M; Makarov, I G; Nezhevenko, O A; Ostreiko, G N; Persov, B Z; Serdobintsev, G V

2004-01-01

A gyrocon together with high-voltage 1.5 MeV accelerator ELIT-3A represents a power generator at 430 MHz serving for linear electron accelerator pulse driving. The facility description and results of calorimetric measurements of ELIT-3A electron beam power and accelerated beam at the end of accelerator are presented in the paper. 2.2 amps of pulsed current have been obtained at electron energy of 20 MeV. The achieved energy conversion efficiency is about 55%.

Economic Multipliers and Mega-Event Analysis

OpenAIRE

Victor Matheson

2004-01-01

Critics of economic impact studies that purport to show that mega-events such as the Olympics bring large benefits to the communities “lucky” enough to host them frequently cite the use of inappropriate multipliers as a primary reason why these impact studies overstate the true economic gains to the hosts of these events. This brief paper shows in a numerical example how mega-events may lead to inflated multipliers and exaggerated claims of economic benefits.

Range of Possible Beam Current in Linac4

CERN Document Server

Lallement, J-B; CERN. Geneva. BE Department

2009-01-01

Linac4 is a new accelerator under construction at CERN. It is designed to accelerate H- ions to 160MeV, for injection into the existing Proton Synchrotron Booster (PSB). It is also the front-end of the SPL Linac, a high energy proton driver that will reach the energy of 5GeV. The Linac baseline design has been done for a nominal beam peak current of 70mA but it will certainly have to deal with different currents. 132 out of 155 quadrupoles in the Linac are permanent magnets, this choice of using PMQ having fixed gradient, mainly in the DTL and in the CCDTL may then entail issues concerning the beam transverse matching and quality from current different from the nominal one. In this paper, we present the beam dynamics performances in Linac4 obtained for different currents.

From Ephemeral Planning to Permanent Urbanism: An Urban Planning Theory of Mega-Events

Directory of Open Access Journals (Sweden)

Eva Kassens-Noor

2016-03-01

Full Text Available Mega-events like the Olympic Games are powerful forces that shape cities. In the wake of mega-events, a variety of positive and negative legacies have remained in host cities. In order to bring some theoretical clarity to debates about legacy creation, I introduce the concepts of the mega-event utopia, dystopia and heterotopia. A mega-event utopia is ideal and imaginary urbanism embracing abstract concepts about economies, socio-political systems, spaces, and societies in the host during events. The mega-event utopia (in contrast to other utopian visions other stakeholders may hold is dictated by the desires of the mega-event owners irrespective of the realities in the event host. In short, a mega-event utopia is the perfect event host from the owner’s perspective. Mega-event utopias are suggested as a theoretical model for the systematic transformation of their host cities. As large-scale events progress as ever more powerful transformers into this century, mega-event dystopias have emerged as negatives of these idealistic utopias. As hybrid post-event landscapes, mega-event heterotopias manifest the temporary mega-event utopia as legacy imprints into the long-term realities in hosting cities. Using the Olympic utopia as an example of a mega-event utopia, I theorize utopian visions around four urban traits: economy, image, infrastructure and society. Through the concept of the mega-event legacy utopia, I also provide some insight toward the operationalization of the four urban traits for a city’s economic development, local place marketing, urban development, and public participation.

MEGAS multi-electrode gas sensor system. Final report; MEGAS - Multi-Elektroden-Gassensorsystem. Abschlussbericht

Energy Technology Data Exchange (ETDEWEB)

Kelleter, J.

2003-07-01

In the context of the MEGAS project, GTE developed and and constructed an electronic system for controlling and data acquisition of sensors for laboratory and test applications. The system is based on microcontrollers and has a data bus connection. Measurements made in order to find out whether the concentrations of a binary gas mixture and combustion gases are detected separately were successful. A demonstration system was constructed. The MEGAS project showed that it is possible to separate two gases by a sensitive layer at constant sensor temperature. The sensor element is a promising technology. Further research is required on suppressing sensor poisoning by siloxanes, and on reduced sensitivity to interfering gases (e.g. ethanol in the case of combustion gases). (orig.)

MEK Inhibitors Reverse cAMP-Mediated Anxiety in Zebrafish

DEFF Research Database (Denmark)

Lundegaard, Pia R.; Anastasaki, Corina; Grant, Nicola J.

2015-01-01

Altered phosphodiesterase (PDE)-cyclic AMP (cAMP) activity is frequently associated with anxiety disorders, but current therapies act by reducing neuronal excitability rather than targeting PDE-cAMP-mediated signaling pathways. Here, we report the novel repositioning of anti-cancer MEK inhibitors...... as anxiolytics in a zebrafish model of anxiety-like behaviors. PDE inhibitors or activators of adenylate cyclase cause behaviors consistent with anxiety in larvae and adult zebrafish. Small-molecule screening identifies MEK inhibitors as potent suppressors of cAMP anxiety behaviors in both larvae and adult...... zebrafish, while causing no anxiolytic behavioral effects on their own. The mechanism underlying cAMP-induced anxiety is via crosstalk to activation of the RAS-MAPK signaling pathway. We propose that targeting crosstalk signaling pathways can be an effective strategy for mental health disorders, and advance...

The physics of high current beams

International Nuclear Information System (INIS)

Lawson, J.D.

1988-05-01

An outline is presented of paraxial charged particle optics in the presence of self-fields arising from the space-charge and current carried by the beam. Solutions of the envelope equations for beams with finite emittance are considered for a number of specific situations, with the approximation that the density profile of the beam is uniform with a sharp edge, so that the focusing remains linear. More realistic beams are then considered, and the problems of matching, emittance growth and stability are discussed. An attempt is made to emphasize physical principles and physical ideas rather than to present the detailed mathematical techniques required for specific problems. The approach is a tutorial one, and several 'exercises' are included in the text. Most of the material is treated in more depth in the author's forthcoming book. (author)

Beam-current monitor for FMIT

International Nuclear Information System (INIS)

Chamberlin, D.D.; Brousseau, A.T.

1981-03-01

The application of a single toroidal core, coupled with very simple circuitry, that results in the production of a simple instrument, and eliminates the problems inherent in the Faraday cup technique for the current measurements of the FMIT injector beam is described

More Intense Mega Heat Waves in the Warmer World

Science.gov (United States)

Choi, G.; Robinson, D. A.

2017-12-01

In this study, changes in the occurrences of heat waves on the globe since the mid- 20th century and the synoptic characteristics of mega heat waves at regional scales in the warmer climate are examined. The NCEP-NCAR reanalysis surface data show that there have been no obvious linear changes in the heat wave frequencies at the continental scales since the mid-20th century, but amplified interdecadal variations led to unprecedented intense heat waves in the recent decades at the regional scales. Such mega heat waves have been more frequently observed in the poleward subtropical climate belts as well as in the interior region of continents. According to the analyses of upper tropospheric data, the occurrences of more intense mega heat waves since the late 20th century may be associated with the expansion of subtropical high pressures. These results suggest that populous cities near the subtropical climate zones should provide proactive mega heat wave warning systems for residents due to their vulnerability to the sudden attack of human lives harvest by mega heat waves in the warmer 21st century.

Influence of the number of cones on speckle patterns in the Laser MegaJoule configuration

International Nuclear Information System (INIS)

Le Cain, A.; Riazuelo, G.; Sajer, J. M.

2013-01-01

This paper investigates statistical properties of hot spots when speckle patterns are generated by the superimposition of multiple laser beams in a 2 cone and a 3 cone Laser MegaJoule configuration in the zone where all the beams overlap. Three different cases of polarizations are investigated: P polarization, S polarization and the case of Double Polarization Smoothing (DPS). It is found that the sizes of the speckles depend on the choice of the polarization and that DPS seems to be the best option in both configurations. It is shown that the longitudinal radius of the hot spots in a 2 cone configuration is bigger than in a 3 cone configuration. (authors)

A multiwire secondary emission profile monitor for small emittance beams

International Nuclear Information System (INIS)

Chehab, R.; Bonnard, J.; Humbert, G.; Leblond, B.; Saury, J.L.

1985-01-01

A secondary emission monitor using two multiwire grids separated by a positively biased collector has been constructed and tested with a 1 GeV electron beam at the Orsay Linac. The monitor installed just before the electron-positron converter has 8 gold-plated-tungsten wires of 0.1 mm diameter equally spaced 0.2 mm apart in each plane. Each wire is connected with an integrator using a low-bias current operational amplifier. The wire planes and the collector are moved into the beam by a stepping motor : that allows beam-position verification. We measured narrow profiles for 1 Amp peak current pulses of 30 nanoseconds width. Profiles are displayed on a scope and allow emittance determination by the three gradient method. Such a monitor is very useful to control the electron beam position and dimensions on the converter, because the positron source dimensions are rather bigger than those of the incident beam and the geometrical acceptance of the positron Linac is limited

Schwann Cells Metabolize Extracellular 2′,3′-cAMP to 2′-AMP

Science.gov (United States)

Verrier, Jonathan D.; Kochanek, Patrick M.

2015-01-01

The 3′,5′-cAMP–adenosine pathway (3′,5′-cAMP→5′-AMP→adenosine) and the 2′,3′-cAMP–adenosine pathway (2′,3′-cAMP→2′-AMP/3′-AMP→adenosine) are active in the brain. Oligodendrocytes participate in the brain 2′,3′-cAMP–adenosine pathway via their robust expression of 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNPase; converts 2′,3′-cAMP to 2′-AMP). Because Schwann cells also express CNPase, it is conceivable that the 2′,3′-cAMP–adenosine pathway exists in the peripheral nervous system. To test this and to compare the 2′,3′-cAMP–adenosine pathway to the 3′,5′-cAMP–adenosine pathway in Schwann cells, we examined the metabolism of 2′,3′-cAMP, 2′-AMP, 3′-AMP, 3′,5′-cAMP, and 5′-AMP in primary rat Schwann cells in culture. Addition of 2′,3′-cAMP (3, 10, and 30 µM) to Schwann cells increased levels of 2′-AMP in the medium from 0.006 ± 0.002 to 21 ± 2, 70 ± 3, and 187 ± 10 nM/µg protein, respectively; in contrast, Schwann cells had little ability to convert 2′,3′-cAMP to 3′-AMP or 3′,5′-cAMP to either 3′-AMP or 5′-AMP. Although Schwann cells slightly converted 2′,3′-cAMP and 2′-AMP to adenosine, they did so at very modest rates (e.g., 5- and 3-fold, respectively, more slowly compared with our previously reported studies in oligodendrocytes). Using transected myelinated rat sciatic nerves in culture medium, we observed a time-related increase in endogenous intracellular 2′,3′-cAMP and extracellular 2′-AMP. These findings indicate that Schwann cells do not have a robust 3′,5′-cAMP–adenosine pathway but do have a 2′,3′-cAMP–adenosine pathway; however, because the pathway mostly involves 2′-AMP formation rather than 3′-AMP, and because the conversion of 2′-AMP to adenosine is slow, metabolism of 2′,3′-cAMP mostly results in the accumulation of 2′-AMP. Accumulation of 2′-AMP in peripheral nerves postinjury could have

Discovery of a cAMP Deaminase That Quenches Cyclic AMP-Dependent Regulation

Science.gov (United States)

Goble, Alissa M.; Feng, Youjun; Raushel, Frank M.; Cronan, John E.

2013-01-01

An enzyme of unknown function within the amidohydrolase superfamily was discovered to catalyze the hydrolysis of the universal second messenger, cyclic-3’, 5’-adenosine monophosphate (cAMP). The enzyme, which we have named CadD, is encoded by the human pathogenic bacterium Leptospira interrogans. Although CadD is annotated as an adenosine deaminase, the protein specifically deaminates cAMP to cyclic-3’, 5’-inosine monophosphate (cIMP) with a kcat/Km of 2.7 ± 0.4 × 105 M−1 s−1 and has no activity on adenosine, adenine, or 5’-adenosine monophosphate (AMP). This is the first identification of a deaminase specific for cAMP. Expression of CadD in Escherichia coli mimics the loss of adenylate cyclase in that it blocks growth on carbon sources that require the cAMP-CRP transcriptional activator complex for expression of the cognate genes. The cIMP reaction product cannot replace cAMP as the ligand for CRP binding to DNA in vitro and cIMP is a very poor competitor of cAMP activation of CRP for DNA binding. Transcriptional analyses indicate that CadD expression represses expression of several cAMP-CRP dependent genes. CadD adds a new activity to the cAMP metabolic network and may be a useful tool in intracellular study of cAMP-dependent processes. PMID:24074367

Cultural Mega-Events as an International, Cultural, and Political Tool

Directory of Open Access Journals (Sweden)

Julia Nikolaeva

2017-12-01

Full Text Available This article is an attempt to offer a conceptual understanding of various kinds of mega-events and to determine their significance as an instrument of the official international cultural policy. The article examines scientific approaches to understanding and classification of mega-events. The case studies focus on such mega-events as international cross-cultural years and cultural forums. The fact that the official foreign policy of¬ten defines and shapes the goals of mega-events proves their value in establishing and promoting a positive international image of the country. Recent Russian experience in organizing cross-cultural years is examined to discuss positive and negative socio-cultural impact.

Broad-beam, high current, metal ion implantation facility

International Nuclear Information System (INIS)

Brown, I.G.; Dickinson, M.R.; Galvin, J.E.; Godechot, X.; MacGill, R.A.

1990-07-01

We have developed a high current metal ion implantation facility with which high current beams of virtually all the solid metals of the Periodic Table can be produced. The facility makes use of a metal vapor vacuum arc ion source which is operated in a pulsed mode, with pulse width 0.25 ms and repetition rate up to 100 pps. Beam extraction voltage is up to 100 kV, corresponding to an ion energy of up to several hundred keV because of the ion charge state multiplicity; beam current is up to several Amperes peak and around 10 mA time averaged delivered onto target. Implantation is done in a broad-beam mode, with a direct line-of-sight from ion source to target. Here we describe the facility and some of the implants that have been carried out using it, including the 'seeding' of silicon wafers prior to CVD with titanium, palladium or tungsten, the formation of buried iridium silicide layers, and actinide (uranium and thorium) doping of III-V compounds. 16 refs., 6 figs

Bolt beam propagation analysis

Science.gov (United States)

Shokair, I. R.

BOLT (Beam on Laser Technology) is a rocket experiment to demonstrate electron beam propagation on a laser ionized plasma channel across the geomagnetic field in the ion focused regime (IFR). The beam parameters for BOLT are: beam current I(sub b) = 100 Amps, beam energy of 1--1.5 MeV (gamma =3-4), and a Gaussian beam and channel of radii r(sub b) = r(sub c) = 1.5 cm. The N+1 ionization scheme is used to ionize atomic oxygen in the upper atmosphere. This scheme utilizes 130 nm light plus three IR lasers to excite and then ionize atomic oxygen. The limiting factor for the channel strength is the energy of the 130 nm laser, which is assumed to be 1.6 mJ for BOLT. At a fixed laser energy and altitude (fixing the density of atomic oxygen), the range can be varied by adjusting the laser tuning, resulting in a neutralization fraction axial profile of the form: f(z) = f(sub 0) e(exp minus z)/R, where R is the range. In this paper we consider the propagation of the BOLT beam and calculate the range of the electron beam taking into account the fact that the erosion rates (magnetic and inductive) vary with beam length as the beam and channel dynamically respond to sausage and hose instabilities.

The emittance of high current heavy ion beams

International Nuclear Information System (INIS)

White, N.R.; Devaney, A.S.

1989-01-01

Ion implantation is the main application for high current heavy ion beams. Transfer ratio is defined as the ratio of the total ion current leaving the ion source to the current delivered to the endstation. This ratio is monitored and logged and its importance is explained. It is also affected by other factors, such as the isotopic and molecular composition of the total ion beam. The transfer ratio reveals the fraction of ions which are intercepted by parts of the beamline system. The effects of these ions are discussed in two categories: processing purity and reliability. In discussing the emittance of ribbon beams, the two orthogonal planes are usually considered separately. Longitudinal emittance is determined by slot length and by plasma ion temperature. It has already been revealed that the longitudinal divergence of the beams from BF3 is perhaps double that of the beam from arsenic vapour or argon, at the same total perveance from the ion source. This poses the question: why is the ion temperature higher for BF3 than for As or Ar? The transverse emittance is in practical terms dominated by the divergence. It is the most fruitful area for improvement in most real-world systems. There is an intrinsic divergence arising from initial ion energies within the plasma, and there is emittance growth that can occur as a result of aberration in the beam extraction optics. (N.K.)

Method for controlling low-energy high current density electron beams

International Nuclear Information System (INIS)

Lee, J.N.; Oswald, R.B. Jr.

1977-01-01

A method and an apparatus for controlling the angle of incidence of low-energy, high current density electron beams are disclosed. The apparatus includes a current generating diode arrangement with a mesh anode for producing a drifting electron beam. An auxiliary grounded screen electrode is placed between the anode and a target for controlling the average angle of incidence of electrons in the drifting electron beam. According to the method of the present invention, movement of the auxiliary screen electrode relative to the target and the anode permits reliable and reproducible adjustment of the average angle of incidence of the electrons in low energy, high current density relativistic electron beams

Visualisation of the high-current e-beams on solid surfaces

Energy Technology Data Exchange (ETDEWEB)

Solomonov, V I; Osipov, V V; Mikhajlov, S G; Lipchak, A I [Russian Academy of Sciences, Ural Division, Ekaterinburg (Russian Federation). Institute of Electrophysics

1997-12-31

Natural minerals such as spodumen, calcite, and Mn-doped apatite crystals may serve as suitable low-cost materials for visualization of high-current electron beams. High-intensity luminescence lasting several tens of minutes has been observed when irradiating natural specimen by electron beams with the current density of 10-1000 A/sq.cm, with energy of 100-300 keV, and pulse duration of 2-50 ns. The luminescent images of the beam cross-section provide information on the beam density profiles, while the images taken in the plane parallel to the beam axis make it possible to estimate the beam penetration depth and, therefore, the beam energy. The method is illustrated by examples of luminescent images taken from the experiment. (J.U.).

Isolation and characterization of cAMP-free and cAMP-bound forms of bovine heart type II cAMP-dependent protein kinase

International Nuclear Information System (INIS)

Cobb, C.E.

1986-01-01

Bovine heart type II cAMP-dependent protein kinase holoenzyme (cAMP-PK) was purified to homogeneity as determined by denaturing SDS-PAGE. An HPLC-DEAE purification step resolved two distinct peaks of cAMP-dependent kinase activity, which were designated Peak 1 and Peak 2 based on their order of elution. They had the same Stoke's radii and had very similar sedimentation coefficients. As determined by densitometric scanning of SDS-PAGE brands, by their mobility on denaturing PAGE, and by the ratios of equilibrium [ 3 H] cAMP binding to maximal kinase activity, the subunit stoichiometry of the two peaks was the same. In a cAMP assay it was found that Peak 1 holoenzyme was cAMP-free, but half of the Peak 2 holoenzyme cAMP binding sites contained cAMP. Dissociation assays indicated that the cAMP was equally distributed in binding Site 1 and Site 2 of Peak 2. Although SDS-PAGE analysis ruled out conversions by proteolysis or autophosphorylation-dephosphorylation, Peak 1 could be partially converted to Peak 2 by the addition of subsaturating amounts of cAMP, and Peak 2 could be partially converted to Peak 1 by aging. The interconvertibility of the two holoenzyme peaks strongly suggested that the difference between the two peaks was caused by the presence of cAMP in Peak 2

Improvement of the 400 kV linac electron source of AmPS

International Nuclear Information System (INIS)

Kroes, F.B.; Beuzekom, M.G. van; Dobbe, N.J.; Es, J.T. van; Jansweijer, P.P.M.; Kruijer, A.H.; Luigjes, G.; Sluijk, T.G.B.

1992-01-01

An existing linac (MEA) injects electrons into the Amsterdam Pulse Stretcher (AmPS) ring. The linac's peak current increases from 20 to 80 mA. This requires the modification of the 400 kV low emittance gun. The fourfold increase of the peak current is obtained by doubling both the gun perveance (new gun part) and the pulsed extractor voltage. To obtain optimum beam quality over this increased current range, the hot deck electronics has been exchanged by a fast high voltage FET switching supply. A built-in microprocessor, coupled to the local computer by optical fibers, is used to monitor and control the gun parameters. The 5 kV gun extractor voltage pulse shape can be monitored by means of an analog fibre transducer with build in calibration. Finally, in order to improve the energy stability of the accelerated electrons, a serial electron-tube stabilizer was added to the 400 kV DC power supply. (K.A.) 4 refs.; 6 figs

Ion beams from high-current PF facilities

Energy Technology Data Exchange (ETDEWEB)

Sadowski, M [Soltan Inst. for Nuclear Studies, Otwock-Swierk (Poland)

1997-12-31

Pulsed beams of fast deuterons and impurity or admixture ions emitted from high-current PF-type facilities operated in different laboratories are dealt with. A short comparative analysis of time-integrated and time-resolved studies is presented. Particular attention is paid to the microstructure of such ion beams, and to the verification of some theoretical models. (author). 5 figs., 19 refs.

Development of capacitive beam position, beam current and Schottky-signal monitors for the Cryogenic Storage Ring (CSR)

International Nuclear Information System (INIS)

Laux, Felix

2011-01-01

In this thesis novel techniques based on capacitive pickups for the determination of the beam current, the beam position and the Schottky-signal in storage rings have been developed. Beam current measurements at the heavy ion storage ring TSR with a capacitive pickup have been found in very good agreement with the theory. Using this device the accurate measurement of beam currents at the TSR far below 1 μA is now possible. This method will also be used at the Cryogenic Storage Ring (CSR) at which beam currents in the range of 1 nA-1 μA are expected. For the first time, position measurements with a resonant amplifier system for capacitive pickups have been examined at the TSR for later use of this technique in the CSR. With this method an increased signal-to-noise ratio can be achieved using a parallel inductance. A comparison with measurements using the rest gas beam profile monitor has shown very good agreement even at very low intensities. Experiments with the cryo-capable electronics for the CSR beam position monitors have shown an achievable quality factor of Q=500, resulting in the prospect of precise position measurements at the CSR even at very low beam currents. The CSR Schottky-Pickup will also be equipped with a resonant amplifier system with a comparable quality factor. An estimation of the signal-to-noise ratio suggests a detection limit of a few protons. (orig.)

Ion current reduction in pinched electron beam diodes

International Nuclear Information System (INIS)

Quintenz, J.P.; Poukey, J.W.

1977-01-01

A new version of a particle-in-cell diode code has been written which permits the accurate treatment of higher-current diodes with greater physical dimensions. Using this code, we have studied ways to reduce the ion current in large-aspect-ratio pinched electron beam diodes. In particular, we find that allowing the ions to reflex in such diodes lowers the ion to electron current ratio considerably. In a 3-MV R/d=24 case this ratio was lowered by a factor of 6--8 compared with the corresponding nonreflexing-ion diode, while still producing a superpinched electron beam

2′,3′-cAMP, 3′-AMP, and 2′-AMP inhibit human aortic and coronary vascular smooth muscle cell proliferation via A2B receptors

Science.gov (United States)

Ren, Jin; Gillespie, Delbert G.

2011-01-01

Rat vascular smooth muscle cells (VSMCs) from renal microvessels metabolize 2′,3′-cAMP to 2′-AMP and 3′-AMP, and these AMPs are converted to adenosine that inhibits microvascular VSMC proliferation via A2B receptors. The goal of this study was to test whether this mechanism also exists in VSMCs from conduit arteries and whether it is similarly expressed in human vs. rat VSMCs. Incubation of rat and human aortic VSMCs with 2′,3′-cAMP concentration-dependently increased levels of 2′-AMP and 3′-AMP in the medium, with a similar absolute increase in 2′-AMP vs. 3′-AMP. In contrast, in human coronary VSMCs, 2′,3′-cAMP increased 2′-AMP levels yet had little effect on 3′-AMP levels. In all cell types, 2′,3′-cAMP increased levels of adenosine, but not 5′-AMP, and 2′,3′-AMP inhibited cell proliferation. Antagonism of A2B receptors (MRS-1754), but not A1 (1,3-dipropyl-8-cyclopentylxanthine), A2A (SCH-58261), or A3 (VUF-5574) receptors, attenuated the antiproliferative effects of 2′,3′-cAMP. In all cell types, 2′-AMP, 3′-AMP, and 5′-AMP increased adenosine levels, and inhibition of ecto-5′-nucleotidase blocked this effect of 5′-AMP but not that of 2′-AMP nor 3′-AMP. Also, 2′-AMP, 3′-AMP, and 5′-AMP, like 2′,3′-cAMP, exerted antiproliferative effects that were abolished by antagonism of A2B receptors with MRS-1754. In conclusion, VSMCs from conduit arteries metabolize 2′,3′-cAMP to AMPs, which are metabolized to adenosine. In rat and human aortic VSMCs, both 2′-AMP and 3′-AMP are involved in this process, whereas, in human coronary VSMCs, 2′,3′-cAMP is mainly converted to 2′-AMP. Because adenosine inhibits VSMC proliferation via A2B receptors, local vascular production of 2′,3′-cAMP may protect conduit arteries from atherosclerosis. PMID:21622827

Sistem Informasi Penjualan Berbasis Kinerja pada Proyek Apartemen Mega City Bekasi

Directory of Open Access Journals (Sweden)

Dyani Ayu Aisyah

2017-12-01

Full Text Available Mega City Apartment Bekasi is an integrated residence with shopping and office center developed by PT. Mega Utama Development. The sales data encountered in the Mega City apartment project is still manualy by using speadsheet application. There has been no centralized data processing with an application support, especially marketing division. The purpose of this study to build a performance-based sales information system at PT. Mega Utama Development. The method used in developing this information system is SDLC. The SDLC model used in the development of this information system is the "Classic Life Cycle" or waterfall model. With the support of performance-based sales information system, the sales process of apartment units in PT. Mega Utama Development becomes more effective and marketing managers can directly control the performance of sales eksekutifs based on performance reports on this information system.

A beam test of prototype time projection chamber using micro ...

Indian Academy of Sciences (India)

We conducted a series of beam tests of prototype TPCs for the international linear collider (ILC) experiment, equipped with an MWPC, a MicroMEGAS, or GEMs as a readout device. The prototype operated successfully in a test beam at KEK under an axial magnetic field of up to 1 T. The analysis of data is now in progress ...

Generation and transportation of low-energy, high-current electron beams

International Nuclear Information System (INIS)

Ozur, G.E.; Proskurovskij, D.I.; Nazarov, D.S.

1996-01-01

Experimental data on the production of low-energy, high-current electron beams in a plasma-filled diode are presented. The highest beam energy density achieved is about 40 J/cm 2 , which makes it possible to treat materials in the mode of intense evaporation of the surface layer. It was shown that the use of a hollow cathode improves the beam homogeneity. The feasibility was demonstrated of the production of low-energy high-current electron beams in a gun with plasma anode based on the use of a reflective discharge. (author). 6 figs., 6 refs

Recent Advances in the Development of Antimicrobial Peptides (AMPs): Attempts for Sustainable Medicine?

Science.gov (United States)

Kokel, Anne; Torok, Marianna

2018-01-17

Since the first isolation of antimicrobial peptides (AMPs) they have attracted extensive interest in medicinal chemistry. However, only a few AMP-based drugs are currently available on the market. Despite their effectiveness, biodegradability, and versatile mode of action that is less likely to induce resistance compared to conventional antibiotics, AMPs suffer from major issues that need to be addressed to broaden their use. Notably, AMPs can lack selectivity leading to side effects and cytotoxicity, and also exhibit in vivo instability. Several strategies are being actively considered to overcome the limitations that restrain the success of AMPs. In the current work, recent strategies reported for improving AMPs in the context of drug design and delivery were surveyed, and also their possible impact on patients and the environment was assessed. As a major advantage AMPs possess an easily tunable skeleton offering opportunities to improve their properties. Strategic structural modifications and the beneficial properties of cyclic or branched AMPs in term of stability have been reported. The conjugation of AMPs with nanoparticles has also been explored to increase their in vivo stability. Other techniques such as the coupling of AMPs with specific antibodies aim to increase the selectivity of the potential drug towards the target. These strategies were evaluated for their effect on the environment highlighting green technologies. Although further research is needed taking into account both environmental and human health consequences of novel AMPs several of these compounds are promising drug candidates for use in sustainable medicine. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

[Physiopathology of cAMP/PKA signaling in neurons].

Science.gov (United States)

Castro, Liliana; Yapo, Cedric; Vincent, Pierre

2016-01-01

Cyclic adenosine monophosphate (cAMP) and the cyclic-AMP dependent protein kinase (PKA) regulate a plethora of cellular functions in virtually all eukaryotic cells. In neurons, the cAMP/PKA signaling cascade controls a number of biological properties such as axonal growth, synaptic transmission, regulation of excitability or long term changes in the nucleus. Genetically-encoded optical biosensors for cAMP or PKA considerably improved our understanding of these processes by providing a real-time measurement in living neurons. In this review, we describe the recent progresses made in the creation of biosensors for cAMP or PKA activity. These biosensors revealed profound differences in the amplitude of the cAMP signal evoked by neuromodulators between various neuronal preparations. These responses can be resolved at the level of individual neurons, also revealing differences related to the neuronal type. At the subcellular level, biosensors reported different signal dynamics in domains like dendrites, cell body, nucleus and axon. Combining this imaging approach with pharmacology or genetical models points at phosphodiesterases and phosphatases as critical regulatory proteins. Biosensor imaging will certainly help understand the mechanism of action of current drugs as well as help in devising novel therapeutic strategies for neuropsychiatric diseases. © Société de Biologie, 2017.

Beam current monitors at the UNILAC

International Nuclear Information System (INIS)

Schneider, N.

1998-01-01

One of the most basic linac operation tools is a beam current transformer. Using outstanding materials, the latest low-noise amplifiers, and some good ideas, a universal current monitoring system has been developed and installed at the UNILAC at GSI. With a dynamic range of 112 dB, covering the low-current range down to 100 nA peak to peak at S/N=1, as well as 25 mA pulses, provided for high-current injection to the SIS synchrotron, a well-accepted diagnostic instrument could be placed at the disposal of the operaters

Gamma and neutron irradiation tests on commercial IC op amps

International Nuclear Information System (INIS)

Kennedy, E.J.; Morris, A.C. Jr.; Su, D.K.

1985-01-01

Experimental results of gamma and neutron irradiation tests on 30 types of integrated-circuit operational amplifiers from 11 manufacturers are presented. All units were low-cost, commercial-grade devices. Op amps were evaluated for changes in offset voltage, input bias current, power supply current, open-loop gain, gain-bandwidth product, slew rate, power-supply and common-mode rejection ratios. Bipolar transistor op amps with resistive collector load resistors for the input stage indicated the best radiation hardness

Anoctamin 9/TMEM16J is a cation channel activated by cAMP/PKA signal.

Science.gov (United States)

Kim, Hyungsup; Kim, Hyesu; Lee, Jesun; Lee, Byeongjun; Kim, Hee-Ryang; Jung, Jooyoung; Lee, Mi-Ock; Oh, Uhtaek

2018-05-01

Anoctamins (ANOs) are multifunctional membrane proteins that consist of 10 homologs. ANO1 (TMEM16A) and ANO2 (TMEM16B) are anion channels activated by intracellular calcium that meditate numerous physiological functions. ANO6 is a scramblase that redistributes phospholipids across the cell membrane. The other homologs are not well characterized. We found ANO9/TMEM16J is a cation channel activated by a cAMP-dependent protein kinase A (PKA). Intracellular cAMP-activated robust currents in whole cells expressing ANO9, which were inhibited by a PKA blocker. A cholera toxin that persistently stimulated adenylate cyclase activated ANO9 as did the application of PKA. The cAMP-induced ANO9 currents were permeable to cations. The cAMP-dependent ANO9 currents were augmented by intracellular Ca 2+ . Ano9 transcripts were predominant in the intestines. Human intestinal SW480 cells expressed high levels of Ano9 transcripts and showed PKA inhibitor-reversible cAMP-dependent currents. We conclude that ANO9 is a cation channel activated by a cAMP/PKA pathway and could play a role in intestine function. Copyright © 2017. Published by Elsevier Ltd.

γ radiation dosimetry in Mega rad range using sugar solution

International Nuclear Information System (INIS)

Venkataramani, R.; Mehta, S.K.; Soman, S.D.

1976-01-01

The formation of malonaldehyde under γ irradiation of solid sucrose and aqueous sucrose, fructose and arabinose solutions has been studied in the Mega rad range. Malonaldehyde (MA) concentration was estimated spectrophotometrically after complexing with 2-thio-barbituric acid. The effect of free radical scavengers (KI and N 2 O) on the yield of MA was investigated. Of the systems studied a 5% aqueous sucrose solution gave a proportional response of MA formation with dose in 0.2 to 5 Mega rad range. A 5% aqueous solution of sucrose prepared from sucrose irradiated in solid state also gave a smooth response of MA yield with dose from 8 to 30 Mega rad. The aqueous and solid sucrose systems together can be conveniently used for dosimetry in the range of 0.2 30 Mega rad. (author)

gamma. radiation dosimetry in Mega rad range using sugar solution

Energy Technology Data Exchange (ETDEWEB)

Venkataramani, R; Mehta, S K; Soman, S D [Bhabha Atomic Research Centre, Bombay (India). Health Physics Div.

1976-09-01

The formation of malonaldehyde under ..gamma.. irradiation of solid sucrose and aqueous sucrose, fructose and arabinose solutions has been studied in the Mega rad range. Malonaldehyde (MA) concentration was estimated spectrophotometrically after complexing with 2-thio-barbituric acid. The effect of free radical scavengers (KI and N/sub 2/O) on the yield of MA was investigated. Of the systems studied a 5% aqueous sucrose solution gave a proportional response of MA formation with dose in 0.2 to 5 Mega rad range. A 5% aqueous solution of sucrose prepared from sucrose irradiated in solid state also gave a smooth response of MA yield with dose from 8 to 30 Mega rad. The aqueous and solid sucrose systems together can be conveniently used for dosimetry in the range of 0.2 30 Mega rad.

Propagation of high-current fast electron beam in a dielectric target

International Nuclear Information System (INIS)

Klimo, O.; Debayle, A.; Tikhonchuk, V.T.

2006-01-01

Complete test of publication follows. A relativistic electron beam with very high current density may be produced during the interaction of a short high intensity laser pulse with a solid target. In Fast Ignition approach to Inertial Confinement Fusion, such beam is supposed to heat a part of the precompressed DT fuel pellet to the conditions of an efficient ignition. For successful implementation of Fast Ignition understanding the propagation and energy deposition of the beam is crucial. A number of processes, mostly associated with the return current, are dissipating the energy of the beam or inhibiting its collimated transport, namely the filamentation. Weibel, two-stream or the recently proposed ionization instability. Ionization instability may develop in a solid dielectric target due to the dependence of the propagation velocity of the beam on the beam density. To study the propagation of high current electron beam in dielectric target, we use a one-dimensional relativistic electrostatic simulation code based on the Particle in Cell method. The code includes ionization processes in dielectric material and collisions of newly generated cold electrons. The current density of the relativistic electron beam used in this work is in the range 3-300 GA/cm 2 , while its length roughly corresponds to the beam, produced by a 40 fs laser pulse. Propagation of the beam in the polyethylene target is studied. The code is complemented by an analytical model, which is applicable og a wider range of beam parameters that are currently beyond our computational possibilities. When the head of the beam enters the plastic target, electric field grows rapidly in consequence of the charge separation and it starts to ionize atoms. In the maximum of the field, which is less than 10% of the atomic field, the density of new free electrons is two orders of magnitude higher than the beam density, which is enough for the current neutralization. Cold electrons are accelerated by the field

The Impact of Beam Deposition on Bootstrap Current of Fast Ion Produced by Neutral Beam Tangential Injection

International Nuclear Information System (INIS)

Huang Qian-Hong; Gong Xue-Yu; Lu Xing-Qiang; Yu Jun; Cao Jin-Jia

2015-01-01

The density profile of fast ions arising from a tangentially injected diffuse neutral beam in tokamak plasma is calculated. The effects of mean free paths and beam tangency radius on the density profile are discussed under typical HL-2A plasmas parameters. The results show that the profile of fast ions is strongly peaked at the center of the plasma when the mean free path at the maximum deuteron density is larger than the minor radius, while the peak value decreases when the mean free path at the maximum deuteron density is larger than twice that of the minor radius due to the beam transmission loss. Moreover, the bootstrap current of fast ions for various mean free paths at the maximum deuteron density is calculated and its density is proved to be closely related to the deposition of the neutral beam. With the electron return current considered, the net current density obviously decreases. Meanwhile, the peak central fast ion density increases when the beam tangency radius approaches the major radius, and the net bootstrap current increases rapidly with the increasing beam tangency radius. (paper)

Generation and transportation of low-energy, high-current electron beams

Energy Technology Data Exchange (ETDEWEB)

Ozur, G E; Proskurovskij, D I; Nazarov, D S [Russian Academy of Sciences, Tomsk (Russian Federation). Institute of High Current Electronics

1997-12-31

Experimental data on the production of low-energy, high-current electron beams in a plasma-filled diode are presented. The highest beam energy density achieved is about 40 J/cm{sup 2}, which makes it possible to treat materials in the mode of intense evaporation of the surface layer. It was shown that the use of a hollow cathode improves the beam homogeneity. The feasibility was demonstrated of the production of low-energy high-current electron beams in a gun with plasma anode based on the use of a reflective discharge. (author). 6 figs., 6 refs.

Resistance and sheet resistance measurements using electron beam induced current

International Nuclear Information System (INIS)

Czerwinski, A.; Pluska, M.; Ratajczak, J.; Szerling, A.; KaPtcki, J.

2006-01-01

A method for measurement of spatially uniform or nonuniform resistance in layers and strips, based on electron beam induced current (EBIC) technique, is described. High electron beam currents are used so that the overall resistance of the measurement circuit affects the EBIC signal. During the evaluation, the electron beam is scanned along the measured object, whose load resistance varies with the distance. The variation is compensated by an adjustable resistance within an external circuit. The method has been experimentally deployed for sheet resistance determination of buried regions of lateral confinements in semiconductor laser heterostructures manufactured by molecular beam epitaxy

Particle-in-cell simulations of electron beam control using an inductive current divider

Energy Technology Data Exchange (ETDEWEB)

Swanekamp, S. B.; Angus, J. R.; Cooperstein, G.; Ottinger, P. F.; Richardson, A. S.; Schumer, J. W.; Weber, B. V. [Plasma Physics Division, Naval Research Laboratory, Washington, District of Columbia 20375 (United States)

2015-11-15

Kinetic, time-dependent, electromagnetic, particle-in-cell simulations of the inductive current divider are presented. The inductive current divider is a passive method for controlling the trajectory of an intense, hollow electron beam using a vacuum structure that inductively splits the beam's return current. The current divider concept was proposed and studied theoretically in a previous publication [Swanekamp et al., Phys. Plasmas 22, 023107 (2015)]. A central post carries a portion of the return current (I{sub 1}), while the outer conductor carries the remainder (I{sub 2}) with the injected beam current given by I{sub b} = I{sub 1} + I{sub 2}. The simulations are in agreement with the theory which predicts that the total force on the beam trajectory is proportional to (I{sub 2}−I{sub 1}) and the force on the beam envelope is proportional to I{sub b}. Independent control over both the current density and the beam angle at the target is possible by choosing the appropriate current-divider geometry. The root-mean-square (RMS) beam emittance (ε{sub RMS}) varies as the beam propagates through the current divider to the target. For applications where control of the beam trajectory is desired and the current density at the target is similar to the current density at the entrance foil, there is a modest 20% increase in ε{sub RMS} at the target. For other applications where the beam is pinched to a current density ∼5 times larger at the target, ε{sub RMS} is 2–3 times larger at the target.

Further explication of mega-crisis concept and feasible responses

Directory of Open Access Journals (Sweden)

Yen Victor Yew-Cho

2017-01-01

Full Text Available The contemporary world is in an era of mega-crises, caused by a host of physical, economic, political, social, and cultural factors. Through a step-by-step explication of the root concepts of problem, mess, and crisis, a mega-crisis is posited to be a set of interacting crises that are severe in impact, complex in nature, and global in fallout, with no seeming end in sight. Compared to a crisis, a mega-crisis is higher in severity and deeper in complexity. The paper argues for a stakeholder perspective in megacrisis response, as relying on the organizational standpoint is inadequate for reaching long-term resolutions.

An accurate low current measurement circuit for heavy iron beam current monitor

International Nuclear Information System (INIS)

Zhou Chaoyang; Su Hong; Mao Ruishi; Dong Chengfu; Qian Yi; Kong Jie

2012-01-01

Heavy-ion beams at 10 6 particles per second have been applied to the treatment of deep-seated inoperable tumors in the therapy terminal of the Heavy Ion Research Facility in Lanzhou (HIRFL) which is located at the Institute of Modern Physics, Chinese Academy of Sciences (IMP, CAS). An accurate low current measurement circuit following a Faraday cup was developed to monitor the beam current at pA range. The circuit consisted of a picoammeter with a bandwidth of 1 kHz and a gated integrator (GI). A low input bias current precision amplifier and new guarding and shielding techniques were used in the picoammeter circuit which allowed as to measure current less than 1 pA with a current gain of 0.22 V/pA and noise less than 10 fA. This paper will also describe a novel compensation approach which reduced the charge injection from switches in the GI to 10 −18 C, and a T-switch configuration which was used to eliminate leakage current in the reset switch.

Collisionless effects on beam-return current systems in solar flares

Science.gov (United States)

Vlahos, L.; Rowland, H. L.

1985-01-01

A theoretical study of the beam-return current system (BRCS) in solar flares shows that the precipitating electrons modify the way in which the return current (RC) is carried by the background plasma. In particular it is found that the RC is not carried by the bulk of the electrons but by a small number of high-velocity electrons. For beam/plasma densities exceeding approximately 0.001, this can reduce the effects of collisions and heating by the RC. For higher-density beams, where the RC could be unstable to current-driven instabilities, the effects of strong turbulence anomalous resistivity prevent the appearance of such instabilities. The main conclusion is that the BRCS is interconnected, and that the beam-generated strong turbulence determines how the RC is carried.

AMP Deaminase 3 Deficiency Enhanced 5′-AMP Induction of Hypometabolism

Science.gov (United States)

Daniels, Isadora Susan; O′Brien, William G.; Nath, Vinay; Zhao, Zhaoyang; Lee, Cheng Chi

2013-01-01

A hypometabolic state can be induced in mice by 5′-AMP administration. Previously we proposed that an underlying mechanism for this hypometabolism is linked to reduced erythrocyte oxygen transport function due to 5′-AMP uptake altering the cellular adenylate equilibrium. To test this hypothesis, we generated mice deficient in adenosine monophosphate deaminase 3 (AMPD3), the key catabolic enzyme for 5′-AMP in erythrocytes. Mice deficient in AMPD3 maintained AMPD activities in all tissues except erythrocytes. Developmentally and morphologically, the Ampd3−/− mice were indistinguishable from their wild type siblings. The levels of ATP, ADP but not 5′-AMP in erythrocytes of Ampd3−/− mice were significantly elevated. Fasting blood glucose levels of the Ampd3−/− mice were comparable to wild type siblings. In comparison to wild type mice, the Ampd3−/− mice displayed a deeper hypometabolism with a significantly delayed average arousal time in response to 5′-AMP administration. Together, these findings demonstrate a central role of AMPD3 in the regulation of 5′-AMP mediated hypometabolism and further implicate erythrocytes in this behavioral response. PMID:24066180

High-current beam dynamics and transport, theory and experiment

International Nuclear Information System (INIS)

Reiser, M.

1986-01-01

Recent progress in the understanding of beam physics and technology factors determining the current and brightness of ion and electron beams in linear accelerators will be reviewed. Topics to be discussed including phase-space density constraints of particle sources, low-energy beam transport include charge neutralization, emittance growth due to mismatch, energy exchange, instabilities, nonlinear effects, and longitudinal bunching

The Mega-Terrorism - The Challenge of the Third Millennium

Directory of Open Access Journals (Sweden)

Daniel Andrișan

2011-06-01

Full Text Available The aim of this article is to describe the "new face" of terrorism in the twenty-first centuryindicating the transition to mass destruction weapons (nuclear terrorism, chemical, biological, toethnic-religious terrorism, the occurrence of massive gray area phenomena of terrorism and how thisphenomenon became a strategic weapon. Mega-terrorism has been existing, at a conceptual level,ever since the 70’s, when the experts of this phenomenon tried to find a semantic cover for thesituations that certain organizations, groups or terrorist or extremist sections would get someWeapons of Mass Destruction Systems. Actually, the 11th of September tragedy proves that megaterrorismrepresents the premeditated destruction, the lack of negotiations, of a tactical goal that wasto be accomplished by means of a threat. The mega-terrorism actors do not intend to get themselvesknown to the public, do not require anything, do not see the threat as means or device to reach theirpurpose. The 21 st century mega-terrorism simple logic is materialized in the systemic destroying ofthe enemy, no longer representing a political power or a government, but an entire ‘disobeying’,‘corrupted’, ‘unfaithful’ population indifferent to the mega-terrorist actors’ desires. New dimensionagainst mega-terrorism determines not only a rethinking of how to combat it, but also the realizationof a conceptual legal framework and measures established to materialize the political decision.

Have the “mega-journals” reached the limits to growth?

Directory of Open Access Journals (Sweden)

Bo-Christer Björk

2015-05-01

Full Text Available A “mega-journal” is a new type of scientific journal that publishes freely accessible articles, which have been peer reviewed for scientific trustworthiness, but leaves it to the readers to decide which articles are of interest and importance to them. In the wake of the phenomenal success of PLOS ONE, several other publishers have recently started mega-journals. This article presents the evolution of mega-journals since 2010 in terms of article publication rates. The fastest growth seems to have ebbed out at around 35,000 annual articles for the 14 journals combined. Acceptance rates are in the range of 50–70%, and speed of publication is around 3–5 months. Common features in mega-journals are alternative impact metrics, easy reusability of figures and data, post-publication discussions and portable reviews from other journals.

Mega-impacts and mantle-melting episodes: tests of possible correlations

International Nuclear Information System (INIS)

Glikson, A.Y.

1996-01-01

The criteria for recognising the effects of impacts by large-diameter extraterrestrial projectiles (D p >>10 km) on thin, geothermally active crust must vary fundamentally from those pertaining to impacts on thick, cooler continental crust. Although the bulk of the terrestrial cratering records has been destroyed by both erosion of elevated terrains and plate subduction, or obscured by burial, a search for Precambrian mega-impacts is facilitated by the preservation of their likely secondary effects: mega-earthquake-triggered faults; ensuing diamictites, and the deposits of turbidity currents; microtektites; spherulitic condensates of vaporised asteroid and target materials; and distal tectonic and igeneous effects. Clues to the origin of thermal events are provided by peaks on isotopic-age histograms of precise U-Pb, Ar-Ar, amd Sm-Nd mineral-whole-rock ages. These peaks, spatially corroborated by detailed mapping of Precambrian terrains, support an episodic nature of at least certain major Precambrian events and some correlations with impact events. Preliminary time-series analyses of Precambrian events yield values consistent with the Phanerozoic galactic rotation period (250 ± 50 Ma), and the solar system's cross-galactic-plane oscillation period (33 ± 3 Ma). It has been demonstrated that possible correlations between mega-impacts and tectonic/thermal events are capable of being tested through isotopic-age studies of diamictites and spherule units of impact origin and of rifting and mafic igneous events. 123 refs., 2 tabs., 7 figs

The MEGA [Muon decays into an Electron and a GAmma ray] hardware trigger system

International Nuclear Information System (INIS)

Szymanski, J.J.; Amann, J.F.; Black, J.K.; Cooper, M.D.; Wright, S.C.; Crocker, J.; Sanders, H.

1988-01-01

The MEGA experiment is designed to search for the rare decay μ → e γ with a branching ratio sensitivity of /approximately/10 -13 . As is typical of rare-decay experiments, extensive, online filtering of the data is required for MEGA. The MEGA experiment uses a hardware pattern-recognition system based on Programmable Array Logic (PAL) devices. Additional events are eliminated in an online ACP system before data are written to tape. The MEGA trigger system is generally applicable where high-rate, short-propagation-delay trigger systems are required. This report contains an introduction to the MEGA experiment, a discussion of the MEGA hardware trigger system and a discussion of the system's measured performance. 4 refs., 3 figs

2',3'-cAMP, 3'-AMP, 2'-AMP and adenosine inhibit TNF-α and CXCL10 production from activated primary murine microglia via A2A receptors.

Science.gov (United States)

Newell, Elizabeth A; Exo, Jennifer L; Verrier, Jonathan D; Jackson, Travis C; Gillespie, Delbert G; Janesko-Feldman, Keri; Kochanek, Patrick M; Jackson, Edwin K

2015-01-12

Some cells, tissues and organs release 2',3'-cAMP (a positional isomer of 3',5'-cAMP) and convert extracellular 2',3'-cAMP to 2'-AMP plus 3'-AMP and convert these AMPs to adenosine (called the extracellular 2',3'-cAMP-adenosine pathway). Recent studies show that microglia have an extracellular 2',3'-cAMP-adenosine pathway. The goal of the present study was to investigate whether the extracellular 2',3'-cAMP-adenosine pathway could have functional consequences on the production of cytokines/chemokines by activated microglia. Experiments were conducted in cultures of primary murine microglia. In the first experiment, the effect of 2',3'-cAMP, 3'-AMP, 2'-AMP and adenosine on LPS-induced TNF-α and CXCL10 production was determined. In the next experiment, the first protocol was replicated but with the addition of 1,3-dipropyl-8-p-sulfophenylxanthine (DPSPX) (0.1 μM; antagonist of adenosine receptors). The last experiment compared the ability of 2-chloro-N(6)-cyclopentyladenosine (CCPA) (10 μM; selective A1 agonist), 5'-N-ethylcarboxamide adenosine (NECA) (10 μM; agonist for all adenosine receptor subtypes) and CGS21680 (10 μM; selective A2A agonist) to inhibit LPS-induced TNF-α and CXCL10 production. (1) 2',3'-cAMP, 3'-AMP, 2'-AMP and adenosine similarly inhibited LPS-induced TNF-α and CXCL10 production; (2) DPSPX nearly eliminated the inhibitory effects of 2',3'-cAMP, 3'-AMP, 2'-AMP and adenosine on LPS-induced TNF-α and CXCL10 production; (3) CCPA did not affect LPS-induced TNF-α and CXCL10; (4) NECA and CGS21680 similarly inhibited LPS-induced TNF-α and CXCL10 production. 2',3'-cAMP and its metabolites (3'-AMP, 2'-AMP and adenosine) inhibit LPS-induced TNF-α and CXCL10 production via A2A-receptor activation. Adenosine and its precursors, via A2A receptors, likely suppress TNF-α and CXCL10 production by activated microglia in brain diseases. Copyright © 2014 Elsevier B.V. All rights reserved.

Events and mega events: leisure and business in tourism

Directory of Open Access Journals (Sweden)

Ricardo Alexandre Paiva

2015-12-01

Full Text Available The promotion of events and mega events mobilizes at the same time, in a concatenated way or not, leisure and business practices, which are captured by the tourism industry as a stimulus for the reproduction of capitalism, by the amount of other activities which raise (primary, secondary and tertiary , placing the architecture and the city as protagonists in contemporary urban development. In this sense, the article analyzes the articulation of events and mega events to the provision of architecture and urban infrastructure, as well as the construction of the tourist image of the places, motivated by leisure and business activities. The methodological procedures have theoretical and exploratory character and have multidisciplinary intentions. This will be discussed, in a historical perspective, the concepts of leisure and business activities that raise as moving or traveling; next it will be delimited similarities and differences between tourism events and business tourism, entering after the analysis of the distinctions between events and mega events, highlighting the complexity and the role of mega-events as a major symptom of globalization; finally it will be presented the spatial scale developments in architecture and the city in the realization of (mega events, as well as its impact on the city's image. As a synthesis, it is important to notice that spatial developments business tourism, events and mega events are manifested in various scales and with different levels of complexity, revealing the strengths and / or weaknesses of the places. The urban planning, architecture and urbanism are important objects of knowledge and spatial intervention to ensure infrastructure and urban and architectural structures appropriate for events, which should be sensitive to the demands of tourists and host communities.

High current precision long pulse electron beam position monitor

CERN Document Server

Nelson, S D; Fessenden, T J; Holmes, C

2000-01-01

Precision high current long pulse electron beam position monitoring has typically experienced problems with high Q sensors, sensors damped to the point of lack of precision, or sensors that interact substantially with any beam halo thus obscuring the desired signal. As part of the effort to develop a multi-axis electron beam transport system using transverse electromagnetic stripline kicker technology, it is necessary to precisely determine the position and extent of long high energy beams for accurate beam position control (6 - 40 MeV, 1 - 4 kA, 2 μs beam pulse, sub millimeter beam position accuracy.) The kicker positioning system utilizes shot-to-shot adjustments for reduction of relatively slow (< 20 MHz) motion of the beam centroid. The electron beams passing through the diagnostic systems have the potential for large halo effects that tend to corrupt position measurements.

RADLAC II high current electron beam propagation experiment

International Nuclear Information System (INIS)

Frost, C.A.; Shope, S.L.; Mazarakis, M.G.; Poukey, J.W.; Wagner, J.S.; Turman, B.N.; Crist, C.E.; Welch, D.R.; Struve, K.W.

1993-01-01

The resistive hose instability of an electron beam was observed to be convective in recent RADLAC II experiments for higher current shots. The effects of air scattering for these shots were minimal. These experiments and theory suggest low-frequency hose motion which does not appear convective may be due to rapid expansion and subsequent drifting of the beam nose

Sunflower mega-environments in Serbia revealed by GGE biplot analysis

Directory of Open Access Journals (Sweden)

Balalić Igor

2013-01-01

Full Text Available Sunflower mega-environment analysis was conducted for the grain yield data of 20 hybrids and 19 test locations during 2006, and 20 hybrids and 16 test locations during 2007. Combined data included 15 hybrids and 9 test locations common for both years and it was analyzed as balanced experiment. The analysis of variance components showed that hybrid by location interaction explained 2.74, 5.8, and 3.72 times more variation than hybrid, for grain yield, for 2006, 2007, combined data, respectively, and indicated potential mega-environment existence. Our results showed the existence of two mega-environments in Serbia sunflower growing region: (1 Kula Vitovnica, Aleksa Šantić, Sombor and (2 Rimski Šančevi, Kikinda. It has been concluded that if we want promising sunflower hybrids to be optimally used, they should be cropped differently for the two determined mega-environments.

Overview of physics results from MAST towards ITER/DEMO and the MAST Upgrade

DEFF Research Database (Denmark)

Meyer, H.; Abel, I.G.; Akers, R.J.

2013-01-01

New diagnostic, modelling and plant capability on the Mega Ampère Spherical Tokamak (MAST) have delivered important results in key areas for ITER/DEMO and the upcoming MAST Upgrade, a step towards future ST devices on the path to fusion currently under procurement. Micro-stability analysis...

Charged particle beam current monitoring tutorial

International Nuclear Information System (INIS)

Webber, R.C.

1994-10-01

A tutorial presentation is made on topics related to the measurement of charged particle beam currents. The fundamental physics of electricity and magnetism pertinent to the problem is reviewed. The physics is presented with a stress on its interpretation from an electrical circuit theory point of view. The operation of devices including video pulse current transformers, direct current transformers, and gigahertz bandwidth wall current style transformers is described. Design examples are given for each of these types of devices. Sensitivity, frequency response, and physical environment are typical parameters which influence the design of these instruments in any particular application. Practical engineering considerations, potential pitfalls, and performance limitations are discussed

Slice of the LHC prototype beam tubes in dipole magnet

CERN Multimedia

1995-01-01

A slice of the LHC accelerator prototype beam tubes surrounded by magnets. The LHC will accelerate two proton beams in opposite directions. The high bending and accelerating fields needed can only be reached using superconductors. At very low temperatures superconductors have no electrical resistance and therefore no power loss. The LHC will be the largest superconducting installation ever built, a unique challenge for CERN and its industrial partners. About dipole magnets: There will be 1232 dipole magnets in the LHC, used to guide the particles around the 27 km ring. Dipole magnets must have an extremely uniform field, which means the current flowing in the coils has to be very precisely controlled. Nowhere before has such precision been achieved at such high currents. The temperature is measured to five thousandths of a degree, the current to one part in a million. The current creating the magnetic field will pass through superconducting wires at up to 12 500 amps, about 30 000 times the current flowing ...

A high resolution Mirnov array for the Mega Ampere Spherical Tokamak

International Nuclear Information System (INIS)

Hole, M. J.; Appel, L. C.; Martin, R.

2009-01-01

Over the past two decades, the increase in neutral-beam heating and α particle production in magnetically confined fusion plasmas has led to an increase in energetic particle driven mode activity, much of which has an electromagnetic signature which can be detected by the use of external Mirnov coils. Typically, the frequency and spatial wave number band of such oscillations increase with increasing injection energy, offering new challenges for diagnostic design. In particular, as the frequency approaches the megahertz range, care must be taken to model the stray capacitance of the coil, which limits the resonant frequency of the probe; model transmission line effects in the system, which if unchecked can produce system resonances; and minimize coil conductive shielding, so as to minimize skin currents which limit the frequency response of the coil. As well as optimizing the frequency response, the coils should also be positioned to confidently identify oscillations over a wide wave number band. This work, which draws on new techniques in stray capacitance modeling and coil positioning, is a case study of the outboard Mirnov array for high-frequency acquisition in the Mega Ampere Spherical Tokamak, and is intended as a roadmap for the design of high frequency, weak field strength magnetic diagnostics.

MEGA-CC: computing core of molecular evolutionary genetics analysis program for automated and iterative data analysis.

Science.gov (United States)

Kumar, Sudhir; Stecher, Glen; Peterson, Daniel; Tamura, Koichiro

2012-10-15

There is a growing need in the research community to apply the molecular evolutionary genetics analysis (MEGA) software tool for batch processing a large number of datasets and to integrate it into analysis workflows. Therefore, we now make available the computing core of the MEGA software as a stand-alone executable (MEGA-CC), along with an analysis prototyper (MEGA-Proto). MEGA-CC provides users with access to all the computational analyses available through MEGA's graphical user interface version. This includes methods for multiple sequence alignment, substitution model selection, evolutionary distance estimation, phylogeny inference, substitution rate and pattern estimation, tests of natural selection and ancestral sequence inference. Additionally, we have upgraded the source code for phylogenetic analysis using the maximum likelihood methods for parallel execution on multiple processors and cores. Here, we describe MEGA-CC and outline the steps for using MEGA-CC in tandem with MEGA-Proto for iterative and automated data analysis. http://www.megasoftware.net/.

Improvement of the 400 kV linac electron source of AmPS

International Nuclear Information System (INIS)

Kroes, F.B.; Beuzekom, M.G. van; Dobbe, N.J.; Es, J.T. van; Jansweijer, P.P.M.; Kruijer, A.H.; Luigjes, G.; Sluijk, T.G.B.

1992-01-01

The installation of the 900 MeV Amsterdam Pulse Stretcher is nearly completed and its commissioning will start Spring 1992. The existing linac MEA will inject electrons in the AmPS ring. The linacs peak current will be increased from 20 to 80 mA. This requires modification of the 400 kV low emittance gun which now will deliver a peak current of maximum 400 mA instead of 100 mA at a pulse width of 2.1 μsec. The fourfold increase of the peakcurrent is obtained by doubling both the gun perveance (new gun part) and the pulsed extractor voltage. After chopping and pre-bunching more than 80 mA will be available for acceleration in MEA. To obtain optimum beam quality over this increased current range the hot deck electronics, operating at -400 kV, has been exchanged by a state of the art fast high voltage FET switching supply. The increased space charge forces in the beam require stronger electro-static focusing in the first electrostatic gap to define the beam diameter at the gun exit. This is accomplished with a 25 kV controlled power supply. A build in microprocessor, coupled to the local computer by optical fibers, is used to monitor and control the gun parameters. The 5kV gun extractor voltage pulse shape can be monitored by means of an analog fibre transducer with build in calibration. Finally, in order to improve the energy stability of the accelerated electrons a serial electron-tube stabilizer was added to the 400 kV DC power supply. A supply stability of 2. 10 -5 has been achieved. (author). 4 refs.; 6 figs

Achromatic beam transport of High Current Injector

International Nuclear Information System (INIS)

Kumar, Sarvesh; Mandal, A.

2016-01-01

The high current injector (HCI) provides intense ion beams of high charge state using a high temperature superconducting ECR ion source. The ion beam is accelerated upto a final energy of 1.8 MeV/u due to an electrostatic potential, a radio frequency quadrupole (RFQ) and a drift tube linac (DTL). The ion beam has to be transported to superconducting LINAC which is around 50 m away from DTL. This section is termed as high energy beam transport section (HEBT) and is used to match the beam both in transverse and longitudinal phase space to the entrance of LINAC. The HEBT section is made up of four 90 deg. achromatic bends and interconnecting magnetic quadrupole triplets. Two RF bunchers have been used for longitudinal phase matching to the LINAC. The ion optical design of HEBT section has been simulated using different beam dynamics codes like TRACEWIN, GICOSY and TRACE 3D. The field computation code OPERA 3D has been utilized for hardware design of all the magnets. All the dipole and quadrupole magnets have been field mapped and their test results such as edge angles measurements, homogeneity and harmonic analysis etc. are reported. The whole design of HEBT section has been performed such that the most of the beam optical components share same hardware design and there is ample space for beam diagnostics as per geometry of the building. Many combination of achromatic bends have been simulated to transport the beam in HEBT section but finally the four 90 deg. achromatic bend configuration is found to be the best satisfying all the geometrical constraints with simplified beam tuning process in real time

A squid-based beam current monitor for FAIR/CRYRING

International Nuclear Information System (INIS)

Geithner, Rene; Stöhlker, Thomas; Kurian, Febin; Reeg, Hansjörg; Schwickert, Marcus; Neubert, Ralf; Seidel, Paul

2015-01-01

A SQUID-based beam current monitor was developed for the upcoming FAIR-Project, providing a non-destructive online monitoring of the beam currents in the nA-range. The cryogenic current comparator (CCC) was optimized for lowest possible noise-limited current resolution together with a high system bandwidth. This CCC is foreseen to be installed in the CRYRING facility (CRYRING@ESR: A study group report www.gsi.de/fileadmin/SPARC/documents/Cryring/ReportCryring-40ESR.PDF), working as a test bench for FAIR. In this contribution we present results of the completed CCC for FAIR/CRYRING and also arrangements that have been done for the installation of the CCC at CRYRING, regarding the cryostat design. (paper)

Design and initial tests of beam current monitoring systems for the APS transport lines

International Nuclear Information System (INIS)

Wang, Xucheng.

1992-01-01

The non-intercepting beam current monitoring systems suitable for a wide, range of beam parameters have been developed for the Advanced Photon Source (APS) low energy transport lines and high energy transport line. The positron or electron beam pulse in the transport lines wig have peak beam currents ranging from 8 mA to 29 A with pulse widths varying from 120 ps to 30 ns and pulse repetition rates from 2 Hz to 60 Hz. The peak beam current or total beam charge is measured with the fast or integrating current transformer, respectively, manufactured by Bergoz. In-house high speed beam signal processing electronics provide a DC level output proportional to the peak current or total charge for the digitizer input. The prototype systems were tested on the linacs which have beam pulse structures similar to that of the APS transport lines. This paper describes the design of beam signal processing electronics and grounding and shielding methods for current transformers. The results of the initial operations are presented. A short introduction on the preliminary design of current monitoring systems for the APS rings is also included

Multi-beam injector development at LBL

International Nuclear Information System (INIS)

Rutkowski, H.L.; Faltens, A.; Brodzik, D.A.; Johnson, R.M.; Pike, C.D.; Vanecek, D.L.; Humphries, S. Jr.; Meyer, E.A.; Hewett, D.W.

1990-06-01

LBL is developing a multi-beam injector that will be used for scaled accelerator experiments related to Heavy Ion Fusion. The device will produce sixteen 0.5 Amp beams of C+ at 2 MeV energy. The carbon arc source has been developed to the point where the emittance is within a factor of four of the design target. Modelling of the source behavior to find ways to reduce the emittance is discussed. Source lifetime and reliability is also of paramount importance to us and data regarding the lifetime and failure modes of different source configurations is discussed. One half of the accelerating column has been constructed and tested at high voltage. One beam experiments in this half column are underway. The second half of the column is being built and the transition 2 MV experiments should begin soon. In addition to beam and source performance we also discuss the controls for the injector and the electronics associated with the source and current injection. 3 refs., 2 figs

Transport and acceleration of the high-current ion beam in magneto-isolated gap

International Nuclear Information System (INIS)

Karas', V.I.; Kornilov, E.A.; Manuilenko, O.V.; Fedorovskaya, O.V.; Tarakanov, V.P.

2015-01-01

The possibility of transportation and acceleration of the high-current ion beam in the magneto-isolated gap has been demonstrated. Found the parameters of the system and beams (the magnetic field produced by the coils with opposing currents, the size of the system, and the parameters of the beams), under which the uniform acceleration of the high-current ion beam all along the gap length is realized. It is shown that the quality of the ion beam, during transport and acceleration, at the exit of the gap is acceptable for many technological applications.

Mega-Planning in Population

Science.gov (United States)

Clark, Sarah C.; Murray, Margo

2005-01-01

Clark and Murray examine the six Critical Performance Factors for Mega planning in an example drawn from the five-year history of the population program of a major west coast philanthropy. In this article, the authors describe the salience and scope of the population issue as it is relates to other global trends; the steps the foundation took to…

Interaction of biodegradative threonine dehydratase (TD) of Escherichia coli with 8-azido-AMP, a photoaffinity analog of AMP

International Nuclear Information System (INIS)

Patil, R.V.; Datta, P.

1987-01-01

Stimulation of TD activity by AMP (Ka = 40 μM) is known to accompany the conversion of monomeric form of the enzyme to its tetramer and a decrease in the Km for threonine. In comparison, 8-azido-AMP (N 3 AMP) simulated TD activity only partially, lowered the Km for threonine and stabilized a dimeric form of the protein. Competition experiments revealed that N 3 AMP exerted an apparent dominant effect in counteracting the AMP-mediated enzyme activation, indicating complex mutual interactions between these ligands. UV irradiation of TD with increasing concentrations of 3 H-N 3 AMP (up to 150 μM) resulted in gradual loss of enzyme activity and concomitant incorporation of N 3 AMP into protein; upon complete inactivation, 0.75 mol of N 3 AMP was bound per mol tetramer. The presence of AMP during photolysis reduced the extent of enzyme inactivation as well as the incorporation of N 3 AMP into protein. Photolabeling of TD with 20 μM 3 H-N 3 AMP revealed one labeled tryptic peptide; at higher N 3 AMP concentrations (>300 μM), two labeled peptides were found, one of which was identical to that found with low N 3 AMP concentration. The cumulative results suggest that N 3 AMP can act as an allosteric modifier and that the peptide labeled at low N 3 AMP may represent the AMP binding site on the protein molecule

Reducing the beam current in Linac4 in pulse to pulse mode.

CERN Document Server

Lallement, JB; CERN. Geneva. BE Department

2009-01-01

In order to deliver different beam intensities to users, we studied the possibility of varying the Linac4 beam current at PS Booster injection in pulse to pulse mode. This report gives the possible configurations of Linac4 Low and Medium Energy Beam Transport lines (LEBT and MEBT) that lead to a consistent current reduction.

MEGA - A next generation mission in Medium Energy Gamma-Ray Astronomy

International Nuclear Information System (INIS)

Kanbach, Gottfried

2001-01-01

A Medium Energy Gamma-Ray Astronomy (MEGA) detector is being developed and proposed for a small satellite mission. MEGA intends to improve the sensitivity at medium γ-ray energies (0.4-50 MeV) by at least an order of magnitude with respect to past instruments. Its large field of view will be especially important for the discovery of transient sources and for conducting all-sky surveys. Key science objectives for MEGA are the investigation of cosmic high-energy accelerators and of nucleosynthesis sites with γ-ray lines. The large-scale structure of the galactic and cosmic diffuse background is another important goal for this mission. MEGA records and images γ-ray events by completely tracking Compton and pair creation interactions in a stack of double sided Si-strip track detectors and 3-D resolving CsI calorimeters

SCALES OF FLOWS: Qatar and the Urban Legacies of Mega Events

Directory of Open Access Journals (Sweden)

Anna Grichting

2013-07-01

Full Text Available In 2022, Qatar will become the first Middle Eastern and Arab country to host such an  important Mega-Event as the FIFA World Cup. Global cultural and sporting Mega Events  ave driven the urban transformation of cities such as Barcelona, London, Rio, Beijing,Shanghai, and Lisbon and the spectacle and economic boosterism encourages cities to  compete on the World Stage for these events. The best practices of successful bids and  their enduring legacies create a knowledge and policy flow of Mega Event strategies for global branding and sustainable Urban, Social, and Economic Development at the local and regional scales. This paper discusses the urban legacies that will result from Qatar hosting the World Cup and other Mega Events, and questions how an emerging global host city like Doha will benefit on the long and short term.

Vasotocin has the potential to inhibit basolateral Na(+)/K (+)-pump current across isolated skin of tree frog in vitro, via its V(2)-type receptor/cAMP pathway.

Science.gov (United States)

Takada, Makoto; Fujimaki, Kayo; Hokari, Shigeru

2008-11-01

Adult frog skin transports Na(+) from the apical to the basolateral side across the skin. Antidiuretic hormone (ADH) is involved in the regulation of Na(+) transport in both mammals and amphibians. We investigated the effect of arginine vasotocin (AVT), the ADH of amphibians, on the short-circuit current (SCC) across intact skin and on the basolateral Na(+)/K(+)-pump current across apically nystatin-permeabilized skin of the tree frog, Hyla japonica, in which the V(2)-type ADH receptor is expressed in vitro. In intact skin, 1 pM AVT had no effect on the SCC, but 10 nM AVT was sufficient to stimulate the SCC since 10 nM and 1 microM of AVT increased the SCC 3.2- and 3.4-fold, respectively (P > 0.9). However, in permeabilized skin, AVT (1 microM) decreased the Na(+)/K(+)-pump current to 0.79 times vehicle control. Similarly, 500 microM of 8Br-cAMP increased the SCC 3.2-fold, yet 1 mM of 8Br-cAMP decreased the Na(+)/K(+)-pump current to 0.76 times vehicle control. Arachidonic acid (10(-5) M) tended to decrease the Na(+)/K(+)-pump current. To judge from these in vitro experiments, AVT has the potential to inhibit the basolateral Na(+)/K(+)-pump current via the V(2)-type receptor/cAMP pathway in the skin of the tree frog.

Application of radiofrequency superconductivity to accelerators for high-current ion beams

International Nuclear Information System (INIS)

Delayen, J.R.; Bohn, C.L.; Kennedy, W.L.; Roche, C.T.; Sagalovsky, L.

1992-01-01

A development program is underway to apply rf superconductivity to the design of continuous-wave (cw) linear accelerators for high-current, high-brightness ion beam. During the last few years, considerable progress has been made both experimentally and theoretically toward this application. Recent tests of niobium resonators for ion acceleration have yielded average accelerating gradients as high as 18 MV/m. In an experiment with a radio-frequency quadrupole geometry, niobium was found to sustain cw peak surface electric fields as high as 128 MV/m over large (10 cm) surface areas. Theoretical studies of beam halo, cumulative beam breakup and alternating-phase focusing have also yielded important results. This paper su-summarizes the recent progress and identifies current and future work in the areas of superconducting accelerator technology for high-current ion beams

Measurements of the temporal onset of mega-Gauss magnetic fields in a laser-driven solenoid

Science.gov (United States)

Goyon, Clement; Polllock, B. B.; Turnbull, D. T.; Hazi, A.; Ross, J. S.; Mariscal, D. A.; Patankar, S.; Williams, G. J.; Farmer, W. A.; Moody, J. D.; Fujioka, S.; Law, K. F. F.

2016-10-01

We report on experimental results obtained at Omega EP showing a nearly linear increase of the B-field up to about 2 mega-Gauss in 0.75 ns in a 1 mm3 region. The field is generated using 1 TW of 351 nm laser power ( 8*1015 W/cm2) incident on a laser-driven solenoid target. The coil target converts about 1% of the laser energy into the B-field measured both inside and outside the coil using proton deflectometry with a grid and Faraday rotation of probe beam through SiO2 glass. Proton data indicates a current rise up to hundreds of kA with a spatial distribution in the Au solenoid conductor evolving in time. These results give insight into the generating mechanism of the current between the plates and the time behavior of the field. These experiments are motivated by recent efforts to understand and utilize High Energy Density (HED) plasmas in the presence of external magnetic fields in areas of research from Astrophysics to Inertial Confinement Fusion. We will describe the experimental results and scale them to a NIF hohlraum size. This work was performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344.

Antimicrobial Peptides (AMPs

Directory of Open Access Journals (Sweden)

Mehrzad Sadredinamin

2016-04-01

Full Text Available Antimicrobial peptides (AMPs are extensive group of molecules that produced by variety tissues of invertebrate, plants, and animal species which play an important role in their immunity response. AMPs have different classifications such as; biosynthetic machines, biological sources, biological functions, molecular properties, covalent bonding patterns, three dimensional structures, and molecular targets.These molecules have multidimensional properties including antimicrobial activity, antiviral activity, antifungal activity, anti-parasite activity, biofilm control, antitumor activity, mitogens activity and linking innate to adaptive immunity that making them promising agents for therapeutic drugs. In spite of this advantage of AMPs, their clinical developments have some limitation for commercial development. But some of AMPs are under clinical trials for the therapeutic purpose such as diabetic foot ulcers, different bacterial infections and tissue damage. In this review, we emphasized on the source, structure, multidimensional properties, limitation and therapeutic applications of various antimicrobial peptides.

Leverage of a sport mega-event branding : a case study of the 2010 FIFA World Cup

OpenAIRE

2014-01-01

D.Comm. (Sport Management) The primary objective of the study was to establish what brand leverage strategies could be implemented in sport mega-event branding based on the case study of the 2010 FIFA World Cup South Africa. The secondary objectives focused on discovering the dimensions of sport mega-event branding, investigating the areas of sport mega-event impacts and leverage, identifying sport mega-event brand leverage activation tools and understanding the role of mega-event brand le...

Mega-electron-volt ultrafast electron diffraction at SLAC National Accelerator Laboratory

Energy Technology Data Exchange (ETDEWEB)

Weathersby, S. P.; Brown, G.; Chase, T. F.; Coffee, R.; Corbett, J.; Eichner, J. P.; Frisch, J. C.; Fry, A. R.; Gühr, M.; Hartmann, N.; Hast, C.; Hettel, R.; Jobe, R. K.; Jongewaard, E. N.; Lewandowski, J. R.; Li, R. K., E-mail: lrk@slac.stanford.edu; Lindenberg, A. M.; Makasyuk, I.; May, J. E.; McCormick, D. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); and others

2015-07-15

Ultrafast electron probes are powerful tools, complementary to x-ray free-electron lasers, used to study structural dynamics in material, chemical, and biological sciences. High brightness, relativistic electron beams with femtosecond pulse duration can resolve details of the dynamic processes on atomic time and length scales. SLAC National Accelerator Laboratory recently launched the Ultrafast Electron Diffraction (UED) and microscopy Initiative aiming at developing the next generation ultrafast electron scattering instruments. As the first stage of the Initiative, a mega-electron-volt (MeV) UED system has been constructed and commissioned to serve ultrafast science experiments and instrumentation development. The system operates at 120-Hz repetition rate with outstanding performance. In this paper, we report on the SLAC MeV UED system and its performance, including the reciprocal space resolution, temporal resolution, and machine stability.

Methods for calculating energy and current requirements for industrial electron beam processing

International Nuclear Information System (INIS)

Cleland, M.R.; Farrell, J.P.

1976-01-01

The practical problems of determining electron beam parameters for industrial irradiation processes are discussed. To assist the radiation engineer in this task, the physical aspects of electron beam absorption are briefly described. Formulas are derived for calculating the surface dose in the treated material using the electron energy, beam current and the area thruput rate of the conveyor. For thick absorbers electron transport results are used to obtain the depth-dose distributions. From these the average dose in the material, anti D, and the beam power utilization efficiency, F/sub p/, can be found by integration over the distributions. These concepts can be used to relate the electron beam power to the mass thruput rate. Qualitatively, the thickness of the material determines the beam energy, the area thruput rate and surface dose determine the beam current while the mass thruput rate and average depth-dose determine the beam power requirements. Graphs are presented showing these relationships as a function of electron energy from 0.2 to 4.0 MeV for polystyrene. With this information, the determination of electron energy and current requirements is a relatively simple procedure

Beam optics of the AmPS extraction line

International Nuclear Information System (INIS)

Hoekstra, R.

1991-01-01

The design of the Amsterdam Pulse Stretcher includes a feasibility study of part of the extraction trajectory. The latter includes some proposed curves projected through the hall of the beam switch yard. Since extraction is performed in the north line of the ring and the connection to the trajectory of the spectrometers is planned in a trajectory parallel to the east line of the ring the curves contain bending magnets for bending 90 degrees either by only two magnets or by making use of ring bending magnets in the same way as the ring curves are constructed. The bending through 90 degrees has optimal imaging properties of a unit cell much the same as the curves in the ring. This one-to-one (or one-to-minus-one) property is intended to shift the known required beam dimensions stream upwards from a defined point in the trajectory of the spectrometers to be able to create the dimensions at this shifted point by means of a so called beam transformer, placed in between the extraction point and this position. This report deals with the further developments with respect to the extraction trajectory. (author). 5 refs.; 9 figs.; 3 tabs

Global mega forces: Implications for the future of natural resources

Science.gov (United States)

George H. Kubik

2012-01-01

The purpose of this paper is to provide an overview of leading global mega forces and their importance to the future of natural resource decisionmaking, policy development, and operation. Global mega forces are defined as a combination of major trends, preferences, and probabilities that come together to produce the potential for future high-impact outcomes. These...

Measurement of electron- and ion beam energies and currents in a plasma focus discharge

International Nuclear Information System (INIS)

Yamamoto, Toshikazu; Kondoh, Yoshiomi; Shimoda, Katsuji; Hirano, Katsumi

1982-01-01

Measurements of energetic particle beams in a plsma focus with a Mather type device are presented. Rogowski coils are used for time-resolved measurement, and solid-state nuclear track detectors for time-integrated measurement of the beams. In the upstream direction with respect to the discharge current, only the electron beam with the maximum current of several kA was detected, which was approximately one percent of the discharge current. The electron energies of the beam were spread from 0.1 to 1 MeV. In the downstream direction, two successive emissions of ions were observed. The first emission had an extremely high energy of the order of some MeV and a low beam current of less than 10 A. The second emission, the main part of the ion beam, with energies of 100 - 800 keV, followed the first one with a time lag of several tens of nanoseconds, and the beam current reached several tens of amperes. (author)

Resistive wall heating due to image current on the beam chamber for a superconducting undulator.

Energy Technology Data Exchange (ETDEWEB)

Kim, S. H. (Accelerator Systems Division (APS))

2012-03-27

The image-current heating on the resistive beam chamber of a superconducting undulator (SCU) was calculated based on the normal and anomalous skin effects. Using the bulk resistivity of copper for the beam chamber, the heat loads were calculated for the residual resistivity ratios (RRRs) of unity at room temperature to 100 K at a cryogenic temperature as the reference. Then, using the resistivity of the specific aluminum alloy 6053-T5, which will be used for the SCU beam chamber, the heat loads were calculated. An electron beam stored in a storage ring induces an image current on the inner conducting wall, mainly within a skin depth, of the beam chamber. The image current, with opposite charge to the electron beam, travels along the chamber wall in the same direction as the electron beam. The average current in the storage ring consists of a number of bunches. When the pattern of the bunched beam is repeated according to the rf frequency, the beam current may be expressed in terms of a Fourier series. The time structure of the image current is assumed to be the same as that of the beam current. For a given resistivity of the chamber inner wall, the application ofthe normal or anomalous skin effect will depend on the harmonic numbers of the Fourier series of the beam current and the temperature of the chamber. For a round beam chamber with a ratius r, much larger than the beam size, one can assume that the image current density as well as the density square, may be uniform around the perimeter 2{pi}r. For the SCU beam chamber, which has a relatively narrow vertical gap compared to the width, the effective perimeter was estimated since the heat load should be proportional to the inverse of the perimeter.

Accessing the mega-region : evaluating the role of livable community patterns in Gulf Coast mega-region planning.

Science.gov (United States)

2015-03-01

This research analyzes both the need and mechanisms for integrating livability components such as : transit and active transportation into a broader mega-regions transportation framework. The research : builds a conceptual framework for understanding...

A low-cost non-intercepting beam current and phase monitor for heavy ions

International Nuclear Information System (INIS)

Bogaty, J.M.; Clifft, B.E.

1995-01-01

A low cost ion beam measurement system has been developed for use at ATLAS. The system provides nondestructive phase and intensity measurement of passing ion beam bunches by sensing their electric fields. Bunches traverse a short tubular electrode thereby inducing displacement currents. These currents are brought outside the vacuum jacket where a lumped inductance resonates electrode capacitance at one of the bunching harmonic frequencies. This configuration yields a basic sensitivity of a few hundred millivolts signal per microampere of beam current. Beam induced radiofrequency signals are summed against an offset frequency generated by the master oscillator. The resulting difference frequency conveys beam intensity and bunch phase information which is sent to separate processing channels. One channel utilizes a phase locked loop to stabilize phase readings during microsecond beam drop outs. The other channel uses a linear full-wave active rectifier circuit which converts sine wave signal amplitude to a DC voltage representing beam current. Plans are in progress to install this new diagnostic at several locations in ATLAS which should help shorten the tuning cycle of new ion species

Tratamento cirúrgico do megaesôfago recidivado

Directory of Open Access Journals (Sweden)

José Luiz Braga de Aquino

Full Text Available OBJETIVO: Avaliar os resultados do tratamento cirúrgico em uma série de pacientes submetidos ao tratamento prévio para megaesôfago que evoluíram com recidiva de sintomas. MÉTODO: Analisou-se os resultados das diversas técnicas operatórias realizadas em 47 pacientes pelo Serviços de Cirurgia Geral e Torácica do HMCP-PUC-Campinas. A morbidade pós-cirúrgica, mortalidade, o alívio ou nova recidiva de sintomas e o tempo de seguimento foram os principais indicadores. Dividiu-se a série em três grupos, de acordo com o grau da afecção: Incipiente (nove casos, Não-avançado (18 casos e avançado (20 casos. As técnicas operatórias utilizadas foram: à cardiomiectomia com fundoplicatura anterior, esofagocardioplastia à Tahl, esofagocardioplastia à Serra-Dória, Esofagectomia Subtotal e Mucosectomia com conservação da túnica muscular esofágica. RESULTADOS: Obteve-se índices de resolutividade satisfatórios com a técnica de cardiomiectomia com fundoplicatura para o megaesôfago Incipiente, com baixa morbidade. Nos megaesôfago não-avançado, as cardiopatias, em especial a esofagocardioplastia à Serra-Dória mostram se mais adequadas. A terapêutica do megaesôfago avançado apresentou as maiores taxas de morbidade e demonstrou superioridade das técnicas mais agressivas em relação às técnicas conservadoras, em especial a mucosectomia com preservação da túnica muscular, sendo esta a técnica com menor morbidade dentro do grupo avançado. CONCLUSÃO: A difícil padronização do tratamento cirúrgico do megaesôfago recidivado deve-se às inúmeras técnicas disponíveis, às habilidades pessoais dos cirurgiões e atenta para a criação de protocolos terapêuticos.

Design and commissioning of the APS beam charge and current monitor

International Nuclear Information System (INIS)

Wang, X.; Lenkszus, F.; Rotela, E.

1994-01-01

The non-intercepting charge and current monitors suitable for a wide range of beam parameters have been developed and installed in the Advanced Photon Source (APS) low energy transport lines, positron accumulator ring (PAR), and injector synchrotron. The positron or electron beam pulse in the APS has charge ranging from 100pC to l0nC with pulse width varying from 30ps to 30ns. The beam charge and current are measured with a current transformer and subsequent current monitoring electronics based on an ultrafast, high precision gated integrator. The signal processing electronics, data acquisition, and communication with the control system are managed by a VME-based system. This paper summarizes the hardware and software features of the systems. The results of recent operations are presented

Design and commissioning of the APS beam charge and current monitors

International Nuclear Information System (INIS)

Wang, X.; Lenkszus, F.; Rotela, E.

1995-01-01

The non-intercepting charge and current monitors suitable for a wide range of beam parameters have been developed and installed in the Advanced Photon Source (APS) low energy transport lines, positron accumulator ring (PAR), and injector synchrotron. The positron or electron beam pulse in the APS has charge ranging from 100 pC to 10 nC with pulse width varying from 30 ps to 30 ns. The beam charge and current are measured with a current transformer and subsequent current monitoring electronics based on an ultrafast, high precision gated integrator. The signal processing electronics, data acquisition, and communication with the control system are managed by a VME-based system. This paper summarizes the hardware and software features of the systems. The results of recent operations are presented. copyright 1995 American Institute of Physics

Agricultural net primary production in relation to that liberated by the extinction of Pleistocene mega-herbivores: an estimate of agricultural carrying capacity?

Energy Technology Data Exchange (ETDEWEB)

Doughty, Christopher E; Field, Christopher B, E-mail: chris.doughty@ouce.ox.ac.uk, E-mail: cfield@ciw.edu [Department of Global Ecology, Carnegie Institution, Stanford, CA 94305 (United States)

2010-10-15

Mega-fauna (defined as animals > 44 kg) experienced a global extinction with 97 of 150 genera going extinct by {approx} 10 000 years ago. We estimate the net primary production (NPP) that was liberated following the global extinction of these mega-herbivores. We then explore how humans, through agriculture, gradually appropriated this liberated NPP, with specific calculations for 800, 1850, and 2000 AD. By 1850, most of the liberated NPP had been appropriated by people, but NPP was still available in the Western US, South America and Australia. NPP liberated following the extinction of the mega-herbivores was {approx} 2.5% ({approx}1.4 (between 1.2 and 1.6) Pg yr{sup -1} of 56 Pg C yr{sup -1}; Pg: petagrams) of global terrestrial NPP. Liberated NPP peaked during the onset of agriculture and was sufficient for sustaining human agriculture until {approx} 320 (250-500) years ago. Humans currently use {approx} 6 times more NPP than was utilized by the extinct Pleistocene mega-herbivores.

Agricultural net primary production in relation to that liberated by the extinction of Pleistocene mega-herbivores: an estimate of agricultural carrying capacity?

International Nuclear Information System (INIS)

Doughty, Christopher E; Field, Christopher B

2010-01-01

Mega-fauna (defined as animals > 44 kg) experienced a global extinction with 97 of 150 genera going extinct by ∼ 10 000 years ago. We estimate the net primary production (NPP) that was liberated following the global extinction of these mega-herbivores. We then explore how humans, through agriculture, gradually appropriated this liberated NPP, with specific calculations for 800, 1850, and 2000 AD. By 1850, most of the liberated NPP had been appropriated by people, but NPP was still available in the Western US, South America and Australia. NPP liberated following the extinction of the mega-herbivores was ∼ 2.5% (∼1.4 (between 1.2 and 1.6) Pg yr -1 of 56 Pg C yr -1 ; Pg: petagrams) of global terrestrial NPP. Liberated NPP peaked during the onset of agriculture and was sufficient for sustaining human agriculture until ∼ 320 (250-500) years ago. Humans currently use ∼ 6 times more NPP than was utilized by the extinct Pleistocene mega-herbivores.

2’,3’-cAMP, 3’-AMP, 2’-AMP and Adenosine Inhibit TNF-α and CXCL10 Production From Activated Primary Murine Microglia via A2A Receptors

Science.gov (United States)

Newell, Elizabeth A.; Exo, Jennifer L.; Verrier, Jonathan D.; Jackson, Travis C.; Gillespie, Delbert G.; Janesko-Feldman, Keri; Kochanek, Patrick M.

2014-01-01

Background Some cells, tissues and organs release 2’,3’-cAMP (a positional isomer of 3’,5’-cAMP) and convert extracellular 2’,3’-cAMP to 2’-AMP plus 3’-AMP and convert these AMPs to adenosine (called the extracellular 2’,3’-cAMP-adenosine pathway). Recent studies show that microglia have an extracellular 2’,3’-cAMP-adenosine pathway. The goal of the present study was to investigate whether the extracellular 2’,3’-cAMP-adenosine pathway could have functional consequences on the production of cytokines/chemokines by activated microglia. Methods Experiments were conducted in cultures of primary murine microglia. In the first experiment, the effect of 2’,3’-cAMP, 3’-AMP, 2’-AMP and adenosine on LPS-induced TNF-α and CXCL10 production was determined. In the next experiment, the first protocol was replicated but with the addition of 1,3-dipropyl-8-p-sulfophenylxanthine (DPSPX) (0.1 µM; antagonist of adenosine receptors). The last experiment compared the ability of 2-chloro-N6-cyclopentyladenosine (CCPA) (10 µM; selective A1 agonist), 5’-N-ethylcarboxamide adenosine (NECA) (10 µM; agonist for all adenosine receptor subtypes) and CGS21680 (10 µM; selective A2A agonist) to inhibit LPS-induced TNF-α and CXCL10 production. Results 1) 2’,3’-cAMP, 3’-AMP, 2’-AMP and adenosine similarly inhibited LPS-induced TNF-α and CXCL10 production; 2) DPSPX nearly eliminated the inhibitory effects of 2’,3’-cAMP, 3’-AMP, 2’-AMP and adenosine on LPS-induced TNF-α and CXCL10 production; 3) CCPA did not affect LPS-induced TNF-α and CXCL10; 4) NECA and CGS21680 similarly inhibited LPS-induced TNF-α and CXCL10 production. Conclusions 2’,3’-cAMP and its metabolites (3’-AMP, 2’-AMP and adenosine) inhibit LPS-induced TNF-α and CXCL10 production via A2A-receptor activation. Adenosine and its precursors, via A2A receptors, likely suppress TNF-α and CXCL10 production by activated microglia in brain diseases. PMID:25451117

Electron beam formation in high-current diode

International Nuclear Information System (INIS)

Korneev, S.A.

1981-01-01

The results of experimental investigation of the electron beam formation in diode with cathode on the base of incomplete discharge over the surface of dielectrics with dielectric penetration epsilon 2 . The measurement of current density distribution over transversal cross section reveals an efficient homogeneity [ru

Temperature calculations of heat loads in rotating target wheels exposed to high beam currents

International Nuclear Information System (INIS)

Greene, John P.; Gabor, Rachel; Neubauer, Janelle

2001-01-01

In heavy-ion physics, high beam currents can eventually melt or destroy the target. Tightly focused beams on stationary targets of modest melting point will exhibit short lifetimes. Defocused or 'wobbled' beams are employed to enhance target survival. Rotating targets using large diameter wheels can help overcome target melting and allow for higher beam currents to be used in experiments. The purpose of the calculations in this work is to try and predict the safe maximum beam currents which produce heat loads below the melting point of the target material

Temperature calculations of heat loads in rotating target wheels exposed to high beam currents

International Nuclear Information System (INIS)

Greene, J. P.; Gabor, R.; Neubauer, J.

2000-01-01

In heavy-ion physics, high beam currents can eventually melt or destroy the target. Tightly focused beams on stationary targets of modest melting point will exhibit short lifetimes. Defocused or wobbled beams are employed to enhance target survival. Rotating targets using large diameter wheels can help overcome target melting and allow for higher beam currents to be used in experiments. The purpose of the calculations in this work is to try and predict the safe maximum beam currents which produce heat loads below the melting point of the target material

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

International Nuclear Information System (INIS)

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

2008-01-01

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

Different impacts of mega-ENSO and conventional ENSO on the Indian summer rainfall: developing phase

Science.gov (United States)

Zhang, Lei; Wu, Zhiwei; Zhou, Yefan

2016-04-01

Mega-El Niño-Southern Oscillation (ENSO), a boarder version of conventional ENSO, is found to be a main driving force of Northern Hemisphere summer monsoon rainfall including the Indian summer rainfall (ISR). The simultaneous impacts of "pure" mega-ENSO and "pure" conventional ENSO events on the ISR in its developing summer remains unclear. This study examines the different linkages between mega-ENSO-ISR and conventional ENSO-ISR. During the developing summer of mega-El Niño, negative rainfall anomalies are seen over the northeastern Indian subcontinent, while the anomalous rainfall pattern is almost the opposite for mega-La Niña; as for the conventional ENSO, the approximate "linear opposite" phenomenon vanishes. Furthermore, the global zonal wave trains anomalous are found at mid-latitude zones, with a local triple circulation pattern over the central-east Eurasia during mega-ENSO events, which might be an explanation of corresponding rainfall response over the Indian Peninsula. Among 106-year historical run (1900-2005) of 9 state-of-the-art models from the Coupled Model Inter-comparison Project Phase 5 (CMIP5), HadGEM2-ES performs a promising skill in simulating the anomalous circulation pattern over mid-latitude and central-east Eurasia while CanESM2 cannot. Probably, it is the models' ability of capturing the mega-ENSO-ISR linkage and the characteristic of mega-ENSO that make the difference.

Cyclic AMP (cAMP)-mediated stimulation of adipocyte differentiation requires the synergistic action of Epac- and cAMP-dependent protein kinase-dependent processes

DEFF Research Database (Denmark)

Petersen, Rasmus Koefoed; Madsen, Lise; Pedersen, Lone Møller

2008-01-01

AMP-dependent stimulation of adipocyte differentiation. Epac, working via Rap, acted synergistically with cAMP-dependent protein kinase (protein kinase A [PKA]) to promote adipogenesis. The major role of PKA was to down-regulate Rho and Rho-kinase activity, rather than to enhance CREB phosphorylation. Suppression of Rho......-kinase impaired proadipogenic insulin/insulin-like growth factor 1 signaling, which was restored by activation of Epac. This interplay between PKA and Epac-mediated processes not only provides novel insight into the initiation and tuning of adipocyte differentiation, but also demonstrates a new mechanism of c......AMP signaling whereby cAMP uses both PKA and Epac to achieve an appropriate cellular response....

Strategies simulation model for the gas business chain MEGAS

International Nuclear Information System (INIS)

Gonzalez, S.M. de; Uzcategui, R.; Brea, E.; Diaz, R.

1994-01-01

MEGAS is a simulation model representing fundamental parameters of Corpoven's natural gas and NGL production, handling, processing, transportation and distribution systems in the Venezuelan mid-east, as well as its financial implications. Various strategies regarding development, prices, costs, new business opportunities, production scenarios, demand and energy policies can be evaluated through this model in order to determine, after analyzing the economics results, a set of strategies to follow in the mid and long term. MEGAS could be also used to make risk analysis studies, considering that probabilistic parameters and variables like gas quality, production, demand, plant shutdowns and others are to be represented by their distinctive function. It is possible to set up a probabilistic function for each economic indicator or operating variables with an appropriate experiment design. MEGAS is based on a dynamic simulation language, which facilitates both the real system components representation and the main variables statistical data accumulation. It also allows graphical representation of results and the simulation animation. Demand and price forecasts, new projects, costs and capabilities of the systems are some of the model input data. MEGAS should be considered as a tool that eases the strategic planning of the business, making it possible for the Corporation to foresee changes, both in the domestic and international market, to predict how these changes could affect its business affairs and to visualize different return scenarios

Pulsed high current ion beam processing equipment

International Nuclear Information System (INIS)

Korenev, S.A.; Perry, A.

1995-01-01

A pulsed high voltage ion source is considered for use in ion beam processing for the surface modification of materials, and deposition of conducting films on different substrates. The source consists of an Arkad'ev-Marx high voltage generator, a vacuum ion diode based on explosive ion emission, and a vacuum chamber as substrate holder. The ion diode allows conducting films to be deposited from metal or allow sources, with ion beam mixing, onto substrates held at a pre-selected temperature. The main variables can be set in the ranges: voltage 100-700 kV, pulse length 0.3 μs, beam current 1-200 A depending on the ion chosen. The applications of this technology are discussed in semiconductor, superconductor and metallizing applications as well as the direction of future development and cost of these devices for commercial application. 14 refs., 6 figs

Production of a high-current microsecond electron beam with a large cross section

International Nuclear Information System (INIS)

Abdullin, E.N.; Belomytsev, S.Ya.; Bugaev, S.P.; Gorbachev, S.I.; Zaslavskii, V.M.; Zorin, V.P.; Koval'chuk, B.M.; Loginov, S.V.; Matyukov, Yu.N.; Rasputin, R.M.; Tolkachev, V.S.; Shchanin, P.M.

1991-01-01

Obtaining high-current wide-aperture electron beams is an important problem in the development of laser technology for controlled nuclear fusion and for solving ecological and technological problems. The main scheme for producing such beams involves the use of generators with intermediate energy storage devices and burst-emission vacuum diodes. Beam pinching is prevented by using an external magnetic field or sectioning the diode into magnetically insulated diodes with currents lower than the limiting current. The length of the electron-current pulse varies from tens to hundreds of nano-seconds and is limited by the parameters of the intermediate storage device. Here the authors study the formation of a high-current electron beam with a square cross section and a current of the order of the limiting current of the diode in the absence of an external magnetic field as well as a 'fast' storage device in the power supply circuit. These conditions as a whole correspond to a simpler electron-source circuit, but the beam forming becomes more complicated. The reason for this is that there is no external magnetic field and that the role of plasma processes in the diode is enhanced by the greater length of the electron-current pulses

Adding value to the decision-making process of mega projects : Fostering strategic ambiguity, redundancy, and resilience

NARCIS (Netherlands)

Giezen, Mendel; Salet, Willem; Bertolini, Luca

2015-01-01

Current practice in decision-making about mega projects seems to be aimed at reducing complexity by simplification. However, this is often detrimental to the resilience and added value of these projects. This article uses the concept of strategic capacity for analyzing the decision-making process on

Beam Current Increase and Cathode Lifetime Improvement of KOTRON-13 Ion Source

International Nuclear Information System (INIS)

Lee, W. K.; Chae, S. K.; Song, J. Y.; Im, G. S.; Cho, B. O.

2010-01-01

Technology of cyclotron has been actively developed to meet the increasing requirement output of medical radioactive isotopes for PET. KOTRON-13 is produced with low negative hydrogen ion beam current owing to the low efficiency of proton beam current compared with foreign cyclotron. In the defect there from, the lifetime of cathode is around 5,000min, which requires frequent maintenance period, and the target beam current is maximum 50uA at a poor efficiency compared with the inflow quantity of hydrogen gas and that of inflicting arc current. Considering above affairs, we have to improve the PIG ion source extraction efficiency of KOTRON-13 in order to lift beam current. Mostly the ion source of cyclotron less than 30Mev comes from the use of PIG ion source mainly with the method of cold cathode or hot cathode. However, the cyclotron of 30Mev grade of EBCO or IBA uses the external ion source and uses ion source with cusp type of good withdrawal efficiency. This type requires high voltage, and transports ion from ion source to cyclotron, which requires precise transportation equipment. And entering cyclotron requires a high quality of inflictor with a high defect rate, but high current cyclotron has no choice but to use ion source of such a method. But the cyclotron using PET with the beam current less than 100uA uses PIG ion source of KOTRON-13 with a reasonable maintenance cost

Beam physics design strategy for a high-current rf linac

Energy Technology Data Exchange (ETDEWEB)

Reiser, M. [Univ. of Maryland, College Park, MD (United States)

1995-10-01

The high average beam power of an rf linac system for transmutation of nuclear waste puts very stringent requirements on beam quality and beam control. Fractional beam losses along the accelerator must be kept at extremely low levels to assure {open_quotes}hands-on{close_quotes} maintenance. Hence, halo formation and large-amplitude tails in the particle distribution due to beam mismatch and equipartitioning effects must be avoided. This implies that the beam should ideally be in near-perfect thermal equilibrium from injection to full energy - in contrast to existing rf linacs in which the transverse temperature, T {sub {perpendicular}}, is higher than the longitudinal temperature, T{sub {parallel}}. The physics and parameter scaling for such a system will be reviewed using the results of recent work on high-intensity bunched beams. A design strategy for a high-current rf linac with equilibrated beam will be proposed.

Silicon radiation detector analysis using back electron beam induced current

International Nuclear Information System (INIS)

Guye, R.

1987-01-01

A new technique for the observation and analysis of defects in silicon radiation detectors is described. This method uses an electron beam from a scanning electron microscope (SEM) impinging on the rear side of the p + n junction of the silicon detector, which itself is active and detects the electron beam induced current (EBIC). It is shown that this current is a sensitive probe of localized trapping centers, either at the junction surface or somewhere in the volume of the silicon crystal. (orig.)

3' : 5'-Cyclic AMP-dependent 3'

NARCIS (Netherlands)

Mato, José M.; Krens, Frans A.; Haastert, Peter J.M. van; Konijn, Theo M.

1977-01-01

Suspensions of 3':5'-cyclic AMP (cAMP)-sensitive cells of Dictyostelium discoideum responded to a cAMP pulse with increased 3':5'-cyclic GMP (cGMP) levels. Under the assay conditions used (2 × 10^8 cells per ml in 10 mM phosphate buffer, pH 6.0) cAMP (5 × 10-8 M final concentration) increased cGMP

Fast-ion transport and neutral beam current drive in ASDEX upgrade

DEFF Research Database (Denmark)

Geiger, B.; Weiland, M.; Jacobsen, Asger Schou

2015-01-01

The neutral beam current drive efficiency has been investigated in the ASDEX Upgrade tokamak by replacing on-axis neutral beams with tangential off-axis beams. A clear modification of the radial fast-ion profiles is observed with a fast-ion D-alpha diagnostic that measures centrally peaked profiles...... during on-axis injection and outwards shifted profiles during off-axis injection. Due to this change of the fast-ion population, a clear modification of the plasma current profile is predicted but not observed by a motional Stark effect diagnostic. The fast-ion transport caused by MHD activity has been...

Sports Mega-Events: Reflections About the Legacies of Uefa Euro Cup

Directory of Open Access Journals (Sweden)

Fillipe Soares Romano

2016-01-01

Full Text Available This essay conducted a literature review of the legacy of sports mega-events, emphasizing the UEFA European Championship. In order to review the academic literature about the subject, we used the following keywords: legacies; sports mega-events and its legacies; UEFA European Championship; and their corresponding terms in Spanish and Portuguese. It was also reviewed some important research basis: Annals; BVS; DOAJ; EBSCO; REDALYC; Periódicos CAPES; PubMed; Scielo; Scopus; Science Direct; and, Scholar Google. The results were analyzed by categories. Regarding the sport mega-event Eurocopa, it was found that the tourism legacies, the economics impacts and the social aspect have been discussed more often, as well as projections and predictions of events that will occur later. It was also concluded that most of the articles shows an absence of discussion about the negative impacts of sports mega-events. It is therefore recommended to use standard methods with comparisons of results and longitudinal studies to better understand the impacts and the use of legacy.

Down-regulation of Cell Surface Cyclic AMP Receptors and Desensitization of Cyclic AMP-stimulated Adenylate Cyclase by Cyclic AMP in Dictyostelium discoideum. Kinetics and Concentration Dependence

NARCIS (Netherlands)

Haastert, Peter J.M. van

1987-01-01

cAMP binds to Dictyostelium discoideum surface receptors and induces a transient activation of adenylate cyclase, which is followed by desensitization. cAMP also induces a loss of detectable surface receptors (down-regulation). Cells were incubated with constant cAMP concentrations, washed free of

Generation of Low-Energy High-Current Electron Beams in Plasma-Anode Electron Guns

Science.gov (United States)

Ozur, G. E.; Proskurovsky, D. I.

2018-01-01

This paper is a review of studies on the generation of low-energy high-current electron beams in electron guns with a plasma anode and an explosive-emission cathode. The problems related to the initiation of explosive electron emission under plasma and the formation and transport of high-current electron beams in plasma-filled systems are discussed consecutively. Considerable attention is given to the nonstationary effects that occur in the space charge layers of plasma. Emphasis is also placed on the problem of providing a uniform energy density distribution over the beam cross section, which is of critical importance in using electron beams of this type for surface treatment of materials. Examples of facilities based on low-energy high-current electron beam sources are presented and their applications in materials science and practice are discussed.

Beam position dependence of a wall-current monitor

International Nuclear Information System (INIS)

Tamiya, K.; Asami, A.; Suwada, T.; Urano, T.; Kobayashi, H.

1995-01-01

It was pointed out recently that there exists an appreciable beam position dependence in the wall-current monitor widely used in electron accelerators. Detailed study of this dependence is performed on a test bench varying the pulse width and the frequency of the input signal simulating the beam. The results of experiments show that when the pulse width becomes shorter more appreciable becomes the dependence, and it approaches to that of calculated from the method of images. A unified analysis is under way. (author)

A beam test of prototype time projection chamber using micro ...

Indian Academy of Sciences (India)

High Energy Accelerator Organization (KEK), Tsukuba 305-0801, Japan. E-mail: makoto.kobayashi.exp@kek.jp. Abstract. We conducted a series of beam tests of prototype TPCs for the international linear collider (ILC) experiment, equipped with an MWPC, a MicroMEGAS, or GEMs as a readout device. The prototype ...

The cyclic AMP cascade is altered in the fragile X nervous system.

Directory of Open Access Journals (Sweden)

Daniel J Kelley

2007-09-01

Full Text Available Fragile X syndrome (FX, the most common heritable cause of mental retardation and autism, is a developmental disorder characterized by physical, cognitive, and behavioral deficits. FX results from a trinucleotide expansion mutation in the fmr1 gene that reduces levels of fragile X mental retardation protein (FMRP. Although research efforts have focused on FMRP's impact on mGluR signaling, how the loss of FMRP leads to the individual symptoms of FX is not known. Previous studies on human FX blood cells revealed alterations in the cyclic adenosine 3', 5'-monophosphate (cAMP cascade. We tested the hypothesis that cAMP signaling is altered in the FX nervous system using three different model systems. Induced levels of cAMP in platelets and in brains of fmr1 knockout mice are substantially reduced. Cyclic AMP induction is also significantly reduced in human FX neural cells. Furthermore, cAMP production is decreased in the heads of FX Drosophila and this defect can be rescued by reintroduction of the dfmr gene. Our results indicate that a robust defect in cAMP production in FX is conserved across species and suggest that cAMP metabolism may serve as a useful biomarker in the human disease population. Reduced cAMP induction has implications for the underlying causes of FX and autism spectrum disorders. Pharmacological agents known to modulate the cAMP cascade may be therapeutic in FX patients and can be tested in these models, thus supplementing current efforts centered on mGluR signaling.

A stable partitioned FSI algorithm for incompressible flow and deforming beams

International Nuclear Information System (INIS)

Li, L.; Henshaw, W.D.; Banks, J.W.; Schwendeman, D.W.; Main, A.

2016-01-01

An added-mass partitioned (AMP) algorithm is described for solving fluid–structure interaction (FSI) problems coupling incompressible flows with thin elastic structures undergoing finite deformations. The new AMP scheme is fully second-order accurate and stable, without sub-time-step iterations, even for very light structures when added-mass effects are strong. The fluid, governed by the incompressible Navier–Stokes equations, is solved in velocity-pressure form using a fractional-step method; large deformations are treated with a mixed Eulerian-Lagrangian approach on deforming composite grids. The motion of the thin structure is governed by a generalized Euler–Bernoulli beam model, and these equations are solved in a Lagrangian frame using two approaches, one based on finite differences and the other on finite elements. The key AMP interface condition is a generalized Robin (mixed) condition on the fluid pressure. This condition, which is derived at a continuous level, has no adjustable parameters and is applied at the discrete level to couple the partitioned domain solvers. Special treatment of the AMP condition is required to couple the finite-element beam solver with the finite-difference-based fluid solver, and two coupling approaches are described. A normal-mode stability analysis is performed for a linearized model problem involving a beam separating two fluid domains, and it is shown that the AMP scheme is stable independent of the ratio of the mass of the fluid to that of the structure. A traditional partitioned (TP) scheme using a Dirichlet–Neumann coupling for the same model problem is shown to be unconditionally unstable if the added mass of the fluid is too large. A series of benchmark problems of increasing complexity are considered to illustrate the behavior of the AMP algorithm, and to compare the behavior with that of the TP scheme. The results of all these benchmark problems verify the stability and accuracy of the AMP scheme. Results for

A stable partitioned FSI algorithm for incompressible flow and deforming beams

Energy Technology Data Exchange (ETDEWEB)

Li, L., E-mail: lil19@rpi.edu [Department of Mathematical Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States); Henshaw, W.D., E-mail: henshw@rpi.edu [Department of Mathematical Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States); Banks, J.W., E-mail: banksj3@rpi.edu [Department of Mathematical Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States); Schwendeman, D.W., E-mail: schwed@rpi.edu [Department of Mathematical Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States); Main, A., E-mail: amain8511@gmail.com [Department of Civil and Environmental Engineering, Duke University, Durham, NC 27708 (United States)

2016-05-01

An added-mass partitioned (AMP) algorithm is described for solving fluid–structure interaction (FSI) problems coupling incompressible flows with thin elastic structures undergoing finite deformations. The new AMP scheme is fully second-order accurate and stable, without sub-time-step iterations, even for very light structures when added-mass effects are strong. The fluid, governed by the incompressible Navier–Stokes equations, is solved in velocity-pressure form using a fractional-step method; large deformations are treated with a mixed Eulerian-Lagrangian approach on deforming composite grids. The motion of the thin structure is governed by a generalized Euler–Bernoulli beam model, and these equations are solved in a Lagrangian frame using two approaches, one based on finite differences and the other on finite elements. The key AMP interface condition is a generalized Robin (mixed) condition on the fluid pressure. This condition, which is derived at a continuous level, has no adjustable parameters and is applied at the discrete level to couple the partitioned domain solvers. Special treatment of the AMP condition is required to couple the finite-element beam solver with the finite-difference-based fluid solver, and two coupling approaches are described. A normal-mode stability analysis is performed for a linearized model problem involving a beam separating two fluid domains, and it is shown that the AMP scheme is stable independent of the ratio of the mass of the fluid to that of the structure. A traditional partitioned (TP) scheme using a Dirichlet–Neumann coupling for the same model problem is shown to be unconditionally unstable if the added mass of the fluid is too large. A series of benchmark problems of increasing complexity are considered to illustrate the behavior of the AMP algorithm, and to compare the behavior with that of the TP scheme. The results of all these benchmark problems verify the stability and accuracy of the AMP scheme. Results for

Two-section linear direct-current accelerator of 1.2 MeV electrons. Mean beam current of 50 mA

International Nuclear Information System (INIS)

Alimov, A.S.; Ermakov, D.I.; Ishkhanov, B.S.; Shvedunov, V.I.; Sakharov, V.P.; Trower, W.P.

2002-01-01

The theoretical and experimental results, obtained by simulation, creation and start-up of the two-section linear electron accelerator, are presented. The following beam parameters: beam current of 49 mA, mean energy of 1.2 MeV, of 59 kV, normalized emittance of 11 mm mrad are determined on the basis of the data on the beam dynamics simulation and the accelerating structure optimization. Special attention is paid to the choice of the version of the SHF-supply system of the two-section accelerator. The version of the SHF-supply system, based on the sections phasing, operating in the auto-oscillation model by means of the synchronizing signal from the feedback chain of the first section into the feedback chain of the second section, is considered. The electron beam parameters on the accelerator outlet (beam current - 44 mA, beam energy - 1.15 MeV, beam efficiency - 50.6 kW) proved to be close to the simulation results [ru

Mega-events in India, Brazil, and South Africa: Lessons for safer cities

International Development Research Centre (IDRC) Digital Library (Canada)

2016-12-13

Dec 13, 2016 ... Hosting global events is a popular strategy for boosting city profiles and spurring economic development. But these mega-events produce winners and losers, as infrastructure projects and private sector development compete for space in established neighbourhoods. Most research on mega-events has ...

High Accuracy Beam Current Monitor System for CEBAF'S Experimental Hall A

International Nuclear Information System (INIS)

J. Denard; A. Saha; G. Lavessiere

2001-01-01

CEBAF accelerator delivers continuous wave (CW) electron beams to three experimental Halls. In Hall A, all experiments require continuous, non-invasive current measurements and a few experiments require an absolute accuracy of 0.2 % in the current range from 1 to 180 (micro)A. A Parametric Current Transformer (PCT), manufactured by Bergoz, has an accurate and stable sensitivity of 4 (micro)A/V but its offset drifts at the muA level over time preclude its direct use for continuous measurements. Two cavity monitors are calibrated against the PCT with at least 50 (micro)A of beam current. The calibration procedure suppresses the error due to PCT's offset drifts by turning the beam on and off, which is invasive to the experiment. One of the goals of the system is to minimize the calibration time without compromising the measurement's accuracy. The linearity of the cavity monitors is a critical parameter for transferring the accurate calibration done at high currents over the whole dynamic range. The method for measuring accurately the linearity is described

The detection of electron-beam-induced current in junctionless semiconductor

International Nuclear Information System (INIS)

Tan, Chee Chin; Ong, Vincent K. S.

2010-01-01

The scanning electron microscope is a versatile tool and its electron beam techniques have been widely used in semiconductor material and device characterizations. One of these electron beam techniques is the electron-beam-induced current (EBIC) technique. One of the limitations of the conventional EBIC technique is that it requires charge collecting junctions which may not be readily available in junctionless samples such as bare substrates unless some special sample preparation procedure such as the fabrication of a diffused junction is done on the junctionless sample. In this paper, the technique of detecting EBIC current in junctionless samples with the use of a two-point probe is presented. It is found that the EBIC current is independent from its physical parameter when the sample thickness is greater than 4L; the width to the right of probe 2 and the width to the left of probe 1 are greater than 2L and 8L, respectively. The parameters affecting this technique of detecting the EBIC current such as the depth of the generation volume, probe spacing, and the applied bias are also discussed in this paper. A commercially available two-dimensional device simulator was used to verify this technique.

Indian manpower for mega nuclear project

CERN Multimedia

2003-01-01

"India is supplying critical scientific manpower and high-tech components needed for building a Large Hadron Collider (LHC) - an accelerator used in particle physics research - a mega scientific project of the European Organisation for Nuclear Research (CERN) worth billions of dollars" (1/2 page).

Unemployment, Entrepreneurial Education and Mega Universities ...

African Journals Online (AJOL)

Individuals acquire education for two broad fundamental reasons, as an investment and as consumption. The investment function of education has continued to create tension for job search leading to cases of unemployment. Entrepreneurship education and establishment of mega universities have being identified as ...

Cyclic AMP in rat pancreatic islets

International Nuclear Information System (INIS)

Grill, V.; Borglund, E.; Cerasi, E.; Uppsala Univ.

1977-01-01

The incorporation of [ 3 H]adenine into cyclic AMP was studied in rat pancreatic islets under varying conditions of labeling. Prolonging the exposure to [ 3 H]adenine progressively augmented the islet cyclic [ 3 H]AMP level. Islets labeled for different periods of time and subsequently incubated (without adenine) in the presence of D-glucose or cholera toxin showed stimulations of intra-islet cyclic [ 3 H]AMP that were proportionate to the levels of radioactive nucleotide present under non-stimulatory conditions. Labeling the islets in a high glucose concentration (27.7 mM) did not modify the nucleotide responses to glucose or cholera toxin. The specific activity of cyclic [ 3 H]AMP, determined by simultaneous assay of cyclic [ 3 H]AMP and total cyclic AMP, was not influenced by glucose or cholera toxin. Glucose had no effect on the specific activity of labeled ATP

Beam-driven currents in the 1/ν regime in a helical system

International Nuclear Information System (INIS)

Nakajima, Noriyoshi; Okamoto, Masao.

1990-04-01

Beam currents driven by a neutral particle injection in a helical system (stellarator, heliotron/torsatron) are studied in the 1/ν collisionality regime. The general expression for the beam-driven current is obtained for arbitrary magnetic field configurations by solving the drift kinetic equation for electrons. It is found that F = J(net)/J(b) (J(net) is the net current and J(b) is the fast ion beam current) increases as f(t) and Zeff where f(t) is the fraction of trapped electrons and Zeff is the effective ionic charge number. Especially, for Zeff ≅ 1 the effect of trapped electrons is large and F is roughly proportional to f(t). On the other hand, if Zeff > or approx 3 the effect of trapped electrons becomes small. (author)

Mega-events in India, Brazil, and South Africa: Lessons for safer cities

International Development Research Centre (IDRC) Digital Library (Canada)

13 déc. 2016 ... Hosting global events is a popular strategy for boosting city profiles and spurring economic development. But these mega-events produce winners and losers, as infrastructure projects and private sector development compete for space in established neighbourhoods. Most research on mega-events has ...

Microcontroller based four-channel current readout unit for beam slit monitor

International Nuclear Information System (INIS)

Holikatti, A.C.; Puntambekar, T.A.; Pithawa, C.K.

2009-01-01

This paper describes the design and development of a microcontroller based four-channel current readout unit for Beam Slit Monitor (BSM) installed in Transport Line-1 of Indus Accelerator Complex. BSM is a diagnostic device consisting of two horizontal and two vertical blades, which can be moved independently in to the beam pipe to cut the beam transversely. The readout unit employs switched integrators with reset, hold and select switches and timing and control unit. It integrates the current output of the four blades of BSM and produces an output corresponding to the beam charge intercepted by the blade. The integrator outputs are then multiplexed and digitized using 12-bit ADC. Acquired digital data from ADC is stored into on-chip RAM of the microcontroller. The readout sequence is synchronized with the Microtron beam-timing signal. The timing of integration, hold and reset cycles is controlled by the microcontroller. The unit is connected on a serial link to the host computer in main control room. This unit has been integrated with the BSM system and is being used to obtain the electron beam profile. (author)

S-AMP for non-linear observation models

DEFF Research Database (Denmark)

Cakmak, Burak; Winther, Ole; Fleury, Bernard H.

2015-01-01

Recently we presented the S-AMP approach, an extension of approximate message passing (AMP), to be able to handle general invariant matrix ensembles. In this contribution we extend S-AMP to non-linear observation models. We obtain generalized AMP (GAMP) as the special case when the measurement...

Development of an IH-type linac for the acceleration of high current heavy ion beams

Energy Technology Data Exchange (ETDEWEB)

Haehnel, Jan Hendrik

2017-07-20

The Facility for Antiproton and Ion Research (FAIR) at GSI Darmstadt will provide unprecedented intensities of protons and heavy ions up to uranium at energies of up to 29 GeV for protons and 2.7 GeV/u for U{sup 28+}. To achieve high intensities in the synchrotron accelerators, high beam currents have to be provided by the injector linear accelerators. High current heavy ion beams are provided by the Universal Linear Accelerator (UNILAC), which in its current state will not be able to provide the required FAIR beam currents. This thesis deals with the development of upgrades for the UNILAC to ensure its high current capability. The first improvement is a matching section (MEBT) for the interface between the RFQ and the IH-DTL of the existing high current injector HSI at the UNILAC. With this new MEBT section, particle losses are eliminated and the overall beam quality is improved. As a second improvement, a complete replacement of the existing Alvarez-DTL is presented. A combination of efficient IH-type cavities and KONUS beam dynamics results in a reduction of the linac length from about 60 m (Alvarez) to just 23 m (new IH-DTL) while providing the same energy and fulfilling FAIR requirements of a high beam current and beam quality. This thesis contains a detailed beam dynamics design of the new linac including some fundamental investigations of the KONUS beam dynamics concept. A cross-check of the beam dynamics design was performed with two independent multi-particle simulation codes. Detailed error studies were conducted to investigate the influence of manufacturing, alignment and operating errors on the beam dynamics performance. Additionally, all five linac cavities were designed, optimized, and their RF parameters including power requirements calculated to provide a comprehensive linac design.

Development of an IH-type linac for the acceleration of high current heavy ion beams

International Nuclear Information System (INIS)

Haehnel, Jan Hendrik

2017-01-01

The Facility for Antiproton and Ion Research (FAIR) at GSI Darmstadt will provide unprecedented intensities of protons and heavy ions up to uranium at energies of up to 29 GeV for protons and 2.7 GeV/u for U 28+ . To achieve high intensities in the synchrotron accelerators, high beam currents have to be provided by the injector linear accelerators. High current heavy ion beams are provided by the Universal Linear Accelerator (UNILAC), which in its current state will not be able to provide the required FAIR beam currents. This thesis deals with the development of upgrades for the UNILAC to ensure its high current capability. The first improvement is a matching section (MEBT) for the interface between the RFQ and the IH-DTL of the existing high current injector HSI at the UNILAC. With this new MEBT section, particle losses are eliminated and the overall beam quality is improved. As a second improvement, a complete replacement of the existing Alvarez-DTL is presented. A combination of efficient IH-type cavities and KONUS beam dynamics results in a reduction of the linac length from about 60 m (Alvarez) to just 23 m (new IH-DTL) while providing the same energy and fulfilling FAIR requirements of a high beam current and beam quality. This thesis contains a detailed beam dynamics design of the new linac including some fundamental investigations of the KONUS beam dynamics concept. A cross-check of the beam dynamics design was performed with two independent multi-particle simulation codes. Detailed error studies were conducted to investigate the influence of manufacturing, alignment and operating errors on the beam dynamics performance. Additionally, all five linac cavities were designed, optimized, and their RF parameters including power requirements calculated to provide a comprehensive linac design.

Electron gun design study for the IUCF beam cooling system

International Nuclear Information System (INIS)

Friesel, D.L.; Ellison, T.; Jones, W.P.

1985-01-01

The design of a low temperature electron beam cooling system for the Indiana University electron-cooled storage ring is in progress. The storage ring, which will accept the light ion beams from the existing k=200, multi-stage cyclotron facility, requires an electron beam variable in energy from about 7 to 275 keV. The electron beam system consists of a high perveance electron gun with Pierce geometry and a flat cathode. The gun and a 28 element accelerating column are immersed in a uniform longitudinal magnetic guide field. A computer modeling study of the system was conducted to determine electron beam density and transverse temperature variations as a function of anode region and accelerator column design parameters. Transverse electron beam temperatures (E /SUB t/ = mc 2 β 2 γ(/theta/ /SUB H/ +/theta/ /SUB v/ )) of less than a few tenths of an electron volt at a maximum current density of 0.4 A/cm 2 are desired over the full energy range. This was achieved in the calculations without the use of resonant focusing for a 2 Amp, 275 keV electron beam. Some systematics of the electron beam temperature variations with system design parameters are presented. A short discussion of the mechanical design of the proposed electron beam system is also given

High Energy Density Physics and Exotic Acceleration Schemes

International Nuclear Information System (INIS)

Cowan, T.; Colby, E.

2005-01-01

The High Energy Density and Exotic Acceleration working group took as our goal to reach beyond the community of plasma accelerator research with its applications to high energy physics, to promote exchange with other disciplines which are challenged by related and demanding beam physics issues. The scope of the group was to cover particle acceleration and beam transport that, unlike other groups at AAC, are not mediated by plasmas or by electromagnetic structures. At this Workshop, we saw an impressive advancement from years past in the area of Vacuum Acceleration, for example with the LEAP experiment at Stanford. And we saw an influx of exciting new beam physics topics involving particle propagation inside of solid-density plasmas or at extremely high charge density, particularly in the areas of laser acceleration of ions, and extreme beams for fusion energy research, including Heavy-ion Inertial Fusion beam physics. One example of the importance and extreme nature of beam physics in HED research is the requirement in the Fast Ignitor scheme of inertial fusion to heat a compressed DT fusion pellet to keV temperatures by injection of laser-driven electron or ion beams of giga-Amp current. Even in modest experiments presently being performed on the laser-acceleration of ions from solids, mega-amp currents of MeV electrons must be transported through solid foils, requiring almost complete return current neutralization, and giving rise to a wide variety of beam-plasma instabilities. As keynote talks our group promoted Ion Acceleration (plenary talk by A. MacKinnon), which historically has grown out of inertial fusion research, and HIF Accelerator Research (invited talk by A. Friedman), which will require impressive advancements in space-charge-limited ion beam physics and in understanding the generation and transport of neutralized ion beams. A unifying aspect of High Energy Density applications was the physics of particle beams inside of solids, which is proving to

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

International Nuclear Information System (INIS)

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

1995-04-01

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

Wideband Precision Current Transformer for the Magnet Current of the Beam Extraction Kicker Magnet of the Large Hadron Collider

CERN Document Server

Gräwer, G

2004-01-01

The LHC beam extraction system is composed of 15 fast kicker magnets per beam to extract the particles in one turn of the collider and to safely dispose them on external absorbers. Each magnet is powered by a separate pulse generator. The generator produces a magnet current pulse with 3 us rise time, 20 kA amplitude and 1.8 ms fall time, of which 90 us are needed to dump the beam. The beam extraction system requires a high level of reliability. To detect any change in the magnet current characteristics, which might indicate a slow degradation of the pulse generator, a high precision wideband current transformer will be installed. For redundancy reasons, the results obtained with this device will be cross-checked with a Rogowski coil, installed adjacent to the transformer. A prototype transformer has been successfully tested at nominal current levels and showed satisfactory results compared with the output of a high frequency resistive coaxial shunt. The annular core of the ring type transformer is composed of...

42 CFR 447.504 - Determination of AMP.

Science.gov (United States)

2010-10-01

... 42 Public Health 4 2010-10-01 2010-10-01 false Determination of AMP. 447.504 Section 447.504... AMP. (a) AMP means, with respect to a covered outpatient drug of a manufacturer (including those sold... wholesalers for drugs distributed to the retail pharmacy class of trade. AMP shall be determined without...

Development of a radio-frequency quadrupole cooler for high beam currents

Science.gov (United States)

Boussaid, Ramzi; Ban, G.; Quéméner, G.; Merrer, Y.; Lorry, J.

2017-12-01

The SHIRaC prototype is a recently developed radio-frequency quadrupole (RFQ) beam cooler with an improved optics design to deliver the required beam quality to a high resolution separator (HRS). For an isobaric separation of isotopes, the HRS demands beams with emittance not exceeding 3 π mm mrad and longitudinal energy spread ˜1 eV . Simulation studies showed a significant contribution of the buffer gas diffusion, space charge effect and mainly the rf fringe field to degrade the achieved beam quality at the RFQ exit. A miniature rf quadrupole (μ RFQ ) has been implemented at that exit to remove the degrading effects and provide beams with 1 eV of energy spread and around 1.75 π mm mrad of emittance for 4 Pa gas pressure. This solution enables also to transmit more than 60% of the incoming ions for currents up to 1 μ A . Detailed studies of this development are presented and discussed in this paper. Transport of beams from SHIRaC towards the HRS has been done with an electrostatic quadrupole triplet. Simulations and first experimental tests showed that more than 95% of ions can reach the HRS. Because SPIRAL-2 beams are of high current and very radioactive, the buffer gas will be highly contaminated. Safe maintenance of the SHIRaC beam line needs exceptional treatment of radioactive contaminants. For that, special vinyl sleep should be mounted on elements to be maintained. A detailed maintenance process will be presented.

When is a Tsunami a Mega-Tsunami?

Science.gov (United States)

Chague-Goff, C.; Goff, J. R.; Terry, J. P.; Goto, K.

2014-12-01

The 2004 Indian Ocean Tsunami is commonly called a mega-tsunami, and this attribute has also been linked to the 2011 Tohoku-oki tsunami. However, since this term was first coined in the early 1990's there have been very few attempts to define it. As such it has been applied in a rather arbitrary fashion to a number of tsunami characteristics, such as wave height or amplitude at both the source and at distant locations, run-up height, geographical extent and impact. The first use of the term is related to a tsunami generated by a large bolide impact and indeed it seems entirely appropriate that the term should be used for such rare events on geological timescales. However, probably as a result of media-driven hyperbole, scientists have used this term at least twice in the last decade, which is hardly a significant portion of the geological timescale. It therefore seems reasonable to suggest that these recent unexpectedly large events do not fall in the category of mega-tsunami but into a category of exceptional events within historical experience and local perspective. The use of the term mega-tsunami over the past 14 years is discussed and a definition is provided that marks the relative uniqueness of these events and a new term, appropriately Japanese in origin, namely that of souteigai-tsunami, is proposed. Examples of these tsunamis will be provided.

Measurements of current density distribution in shaped e-beam writers

Czech Academy of Sciences Publication Activity Database

Bok, Jan; Horáček, Miroslav; Kolařík, Vladimír; Urbánek, Michal; Matějka, Milan; Krzyžánek, Vladislav

2016-01-01

Roč. 149, JAN 5 (2016), s. 117-124 ISSN 0167-9317 R&D Projects: GA ČR(CZ) GA14-20012S; GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : shaped e-beam writer * electron beam * current density Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 1.806, year: 2016

Nonlinear Charge and Current Neutralization of an Ion Beam Pulse in a Pre-formed Plasma

International Nuclear Information System (INIS)

Kaganovich, Igor D.; Shvets, Gennady; Startsev, Edward; Davidson, Ronald C.

2001-01-01

The propagation of a high-current finite-length ion beam in a cold pre-formed plasma is investigated. The outcome of the calculation is the quantitative prediction of the degree of charge and current neutralization of the ion beam pulse by the background plasma. The electric magnetic fields generated by the ion beam are studied analytically for the nonlinear case where the plasma density is comparable in size with the beam density. Particle-in-cell simulations and fluid calculations of current and charge neutralization have been performed for parameters relevant to heavy ion fusion assuming long, dense beams with el >> V(subscript b)/omega(subscript b), where V(subscript b) is the beam velocity and omega subscript b is the electron plasma frequency evaluated with the ion beam density. An important conclusion is that for long, nonrelativistic ion beams, charge neutralization is, for all practical purposes, complete even for very tenuous background plasmas. As a result, the self-magnetic force dominates the electric force and the beam ions are always pinched during beam propagation in a background plasma

Nonlinear Charge and Current Neutralization of an Ion Beam Pulse in a Pre-formed Plasma

Energy Technology Data Exchange (ETDEWEB)

Igor D. Kaganovich; Gennady Shvets; Edward Startsev; Ronald C. Davidson

2001-01-30

The propagation of a high-current finite-length ion beam in a cold pre-formed plasma is investigated. The outcome of the calculation is the quantitative prediction of the degree of charge and current neutralization of the ion beam pulse by the background plasma. The electric magnetic fields generated by the ion beam are studied analytically for the nonlinear case where the plasma density is comparable in size with the beam density. Particle-in-cell simulations and fluid calculations of current and charge neutralization have been performed for parameters relevant to heavy ion fusion assuming long, dense beams with el >> V(subscript b)/omega(subscript b), where V(subscript b) is the beam velocity and omega subscript b is the electron plasma frequency evaluated with the ion beam density. An important conclusion is that for long, nonrelativistic ion beams, charge neutralization is, for all practical purposes, complete even for very tenuous background plasmas. As a result, the self-magnetic force dominates the electric force and the beam ions are always pinched during beam propagation in a background plasma.

Characterization of the particulate air pollution in contrasted mega cities

International Nuclear Information System (INIS)

Favez, O.

2008-02-01

This work aims at characterizing the physics and the chemistry that govern particulate air pollution in two mega cities (Paris and Cairo) for which the size distribution and the chemical composition of airborne particles were poorly documented. Seasonal variations of the main aerosol sources and transformation processes are investigated in these two urban centres, with a particular attention to semi-volatile material and secondary organic aerosols. Short-term health effects of Paris size-segregated aerosols, as well as particulate pollution during the Cairo 'Black Cloud' season, are also emphasized here. Finally, the comparison of results obtained for the two mega cities and for another one (Beijing) allows investigating main factors responsible for particulate air pollution in urban centres with contrasted climatic conditions and development levels. Notably, this work also allows the build-up of an experimental dataset which is now available for the modelling of urban air quality and of environmental impacts of mega city air pollution. (author)

Asteroids from a Martian Mega Impact

Science.gov (United States)

Kohler, Susanna

2018-04-01

Like evidence left at a crime scene, the mineral olivine may be the clue that helps scientists piece together Marss possibly violent history. Could a long-ago giant impact have flung pieces of Mars throughout our inner solar system? Two researchers from the Tokyo Institute of Technology in Japan are on the case.A Telltale MineralOlivine, a mineral that is common in Earths subsurface but weathers quickly on the surface. Olivine is a major component of Marss upper mantle. [Wilson44691]Olivine is a major component of the Martian upper mantle, making up 60% of this region by weight. Intriguingly, olivine turns up in other places in our solar system too for instance, in seven out of the nine known Mars Trojans (a group of asteroids of unknown origin that share Marss orbit), and in the rare A-type asteroids orbiting in the main asteroid belt.How did these asteroids form, and why are they so olivine-rich? An interesting explanation has been postulated: perhaps this olivine all came from the same place Mars as the result of a mega impact billions of years ago.Evidence for ImpactMars bears plenty of signs pointing to a giant impact in its past. The northern and sourthern hemispheres of Mars look very different, a phenomenon referred to as the Mars hemisphere dichotomy. The impact of a Pluto-sized body could explain the smooth Borealis Basin that covers the northern 40% of Marss surface.This high-resolution topographic map of Mars reveals the dichotomy between its northern and sourthern hemispheres. The smooth region in the northern hemisphere, the Borealis basin, may have been formed when a giant object impacted Mars billions of years ago. [NASA/JPL/USGS]Other evidence piles up: Marss orbit location, its rotation speed, the presence of its two moons all could be neatly explained by a large impact around 4 billion years ago. Could such an impact have also strewn debris from Marss mantle across the solar system?To test this theory, we need to determine if a mega impact is

Study of the pulse power supply unit for the four-horn system of the CERN to Fréjus neutrino super beam

CERN Document Server

Baussan, E; Dracos, M; Gaudiot, G; Osswald, F; Poussot, P; Vassilopoulos, N; Wurtz, J; Zeter, V

2013-01-01

The power supply studies for the four-horn system for the CERN to Fréjus neutrino Super Beam oscillation experiment are discussed here. The power supply is being studied to meet the physics potential and the mega-watt (MW) power requirements of the proton driver of the Super Beam. A one-half sinusoid current waveform with a 350 kA maximum current and pulse length of 100 \\mu s at 50 Hz frequency is generated and distributed to four-horns. In order to provide the necessary current needed to focus the charged mesons producing the neutrino beam, a bench of capacitors is charged at 50 Hz frequency to a +12 kV reference voltage and then discharged through a large switch to each horn via a set of strip-lines at the same rate. A current recovery stage allows to invert rapidly the negative voltage of the capacitor after the discharging stage in order to recuperate large part of the injected energy and thus to limit the power consuption. The energy recovery efficiency of that system is very high at 97%. For feasibilit...

A Fast Non Intercepting Linac Electron Beam Position and Current Monitor

DEFF Research Database (Denmark)

Hansen, Jørgen-Walther; Wille, Mads

1982-01-01

A non-intercepting beam monitor consisting of four detecting loops is used to determine the spatial postion and current of a pulsed beam from an electron linear accelerator. The monitor detects the magnetic field radiated by the substructure of the electron bunches created by the accelerating...

Guiding effect of bent macroscopic quartz tube for high current electron beam

International Nuclear Information System (INIS)

Zhang Mingwu; Chen Jing; Wu Yehong; Yang Bian; Wang Wei; Xue Yingli; Yu Deyang; Cai Xiaohong

2012-01-01

By using an incident electron beam with the high current and high energy, the guiding effect of the bent macroscopic quartz tube for the electron beam has been investigated. The angular distributions of outgoing electrons depending on the current and energy of incident electrons were measured. The dependences of electron transmitted fraction on energy and current of incident electrons are also shown. As the incident electron energy increasing, the electron transmitted fraction increases, but it decreases while the incident electron current increasing. The results have been compared with the present data. This work presents, the process of guiding electrons is essentially different from that of guiding highly charged ions, the guiding electron beam was caused by both elastic and inelastic collisions between electrons and inner walls of quartz tube, rather than self-organized charging effect on the surface of inner wall of quartz tube. (authors)

Ampère–Maxwell law for a conducting wire: a topological perspective

International Nuclear Information System (INIS)

Ferreira, J M; Anacleto, Joaquim

2013-01-01

The integral form of Ampère–Maxwell's law for an arbitrarily-shaped wire is recast from a topological perspective, eliminating the need to use conduction current and displacement current terms to determine the magnetic field circulation around an arbitrarily-shaped loop. A generalized flux of the electric field is defined, enabling Ampère–Maxwell's law for magnetic field circulation to be written in a form which parallels that in the absence of conduction current. It is hoped that this work has educational interest since it provides an example of how topology can simplify the formulation of physical laws. The ideas presented herein are primarily intended for undergraduate students of electromagnetism, but may also be of interest to graduate students and teachers. (paper)

Development of a high current 60 keV neutral lithium beam injector for beam emission spectroscopy measurements on fusion experiments

Science.gov (United States)

Anda, G.; Dunai, D.; Lampert, M.; Krizsanóczi, T.; Németh, J.; Bató, S.; Nam, Y. U.; Hu, G. H.; Zoletnik, S.

2018-01-01

A 60 keV neutral lithium beam system was designed and built up for beam emission spectroscopy measurement of edge plasma on the KSTAR and EAST tokamaks. The electron density profile and its fluctuation can be measured using the accelerated lithium beam-based emission spectroscopy system. A thermionic ion source was developed with a SiC heater to emit around 4-5 mA ion current from a 14 mm diameter surface. The ion optic is following the 2 step design used on other devices with small modifications to reach about 2-3 cm beam diameter in the plasma at about 4 m from the ion source. A newly developed recirculating sodium vapour neutralizer neutralizes the accelerated ion beam at around 260-280 °C even during long (manipulation techniques are applied to allow optimization, aiming, cleaning, and beam modulation. The maximum 60 keV beam energy with 4 mA ion current was successfully reached at KSTAR and at EAST. Combined with an efficient observation system, the Li-beam diagnostic enables the measurement of the density profile and fluctuations on the plasma turbulence time scale.

Applicability of "MEGA"[Eighth Note] to Sexually Abusive Youth with Low Intellectual Functioning

Science.gov (United States)

Miccio-Fonseca, L. C.; Rasmussen, Lucinda A.

2013-01-01

The study explored the predictive validity of "Multiplex Empirically Guided Inventory of Ecological Aggregates for Assessing Sexually Abusive Children and Adolescents (Ages 4 to 19)" ("MEGA"[eighth note]; Miccio-Fonseca, 2006b), a comprehensive developmentally sensitive risk assessment outcome tool. "MEGA"[eighth note] assesses risk for coarse…

Soft X-ray beam induced current technique

Energy Technology Data Exchange (ETDEWEB)

Watts, B; Ade, H [Department of Physics, North Carolina State University, Raleigh, NC 27695 (United States); Queen, D; Hellman, F [Department of Physics, University of California, Berkeley, CA 94720 (United States); Kilcoyne, A L D; Tyliszczak, T, E-mail: benjamin.watts@gmail.co [Advanced Light Source, Lawrence Berkeley Nat. Lab., Berkeley, CA 94720 (United States)

2009-09-01

Direct mapping of the charge transport efficiency of polymer solar cell devices using a soft X-ray beam induced current (SoXBIC) method is described. By fabricating a polymer solar cell on an x-ray transparent substrate, we demonstrate the ability to map polymer composition and nanoscale structure within an operating solar cell device and to simultaneously measure the local charge transport efficiency via the short-circuit current. A simple model is calculated and compared to experimental SoXBIC data of a PFB:F8BT bulk-heterojunction device in order to gain greater insight into the device operation and physics.

A review of high beam current RFQ accelerators and funnels

International Nuclear Information System (INIS)

Schneider, J.D.

1998-01-01

The authors review the design features of several high-current (> 20-mA) and high-power (> 1-mA average) proton or H - injectors, RFQs, and funnels. They include a summary of observed performance and will mention a sampling of new designs, including the proposed incorporation of beam choppers. Different programs and organizations have chosen to build the RFQ in diverse configurations. Although the majority of RFQs are either low-current or very low duty-factor, several versions have included high-current and/or high-power designs for either protons or H - ions. The challenges of cooling, handling high space-charge forces, and coupling with injectors and subsequent accelerators are significant. In all instances, beam tests were a valuable learning experience, because not always did these as-built structures perform exactly as predicted by the earlier design codes. They summarize the key operational parameters, indicate what was achieved, and highlight what was learned in these tests. Based on this generally good performance and high promise, even more challenging designs are being considered for new applications that include even higher powers, beam funnels and choppers

Mega hub for intermodal transport - the planning of the most advanced container terminal in the world; Mega-Drehscheibe fuer den Kombinierten Verkehr - Planung des modernsten Containerbahnhofes der Welt

Energy Technology Data Exchange (ETDEWEB)

Franke, K.P. [Noell Stahl- und Maschinenbau GmbH, Wuerzburg (Germany). Abt. Hafentechnik

1998-12-31

The introduction of innovative mega hub systems for the operation of cargo trains is a promising starting point for increasing the efficiency of intermodal transport. A first mega hub as it is known has been planned for Northern Germany with its centre in Lehrte near Hannover. Instead of shunting the waggons, containers will be transferred from train to train at the mega hub. This is not only faster, but also more economical and thus more attractive to rail transport clients. No other known system can achieve such high transhipment/shunting capacities per surface unit. The design of the system guarantees the maximum degree of flexibility in transhipment operations. A high degree of automation will ensure the quality and speed of transhipment. The technical development of the fast transhipment system (FTS) by Noell has been completed. (orig.) [Deutsch] Ein vielversprechender Ansatz fuer die Steigerung der Leistungsfaehigkeit des Kombinierten Verkehrs (KV) ist die Einfuehrung von innovativen Drehscheibensystemen fuer den Betrieb der Cargo-Zuege. Eine erste sogenannte Mega-Drehscheibe wurde fuer den Norden Deutschlands mit Zentrum Lehrte bei Hannover geplant. Statt zu rangieren sollen in der Mega-Drehscheibe die Behaelter zwischen den Zuegen umsteigen. Das ist schneller, kostenguenstiger und damit attraktiver fuer den Bahnkunden. Darueber hinaus ist kein System bekannt, bei dem eine so hohe Umschlag-/Umstelleistung je Flaecheneinheit realisiert werden kann. Die Gestaltung der Anlage gewaehrt eine maximale Flexibilitaet im Umschlagbetrieb. Ein hoher Automatisierungsgrad wird Qualitaet und Schnelligkeit des Umschlages sichern. Die technische Entwicklung der Schnellumschlagtechnik seitens Noell ist abgeschlossen. (orig.)

Qualitative Approach on Investigating Failure Factors of Yemeni Mega Construction Projects

OpenAIRE

Gamil Yaser; Abdul Rahman Ismail; Nagapan Sasitharan; Alemad Nashwan

2017-01-01

Large construction projects in Yemen face many impediments and challenges to be completed successfully. This article presents an investigative cases study of three mega construction projects which are considered failed to achieve their assigned plans and objectives. An exploratory interview was implied in this study via telephone to three construction experts who involved directly in these mega projects at the managerial level. Semi-structured questions based on literature were designed as gu...

Mesozoic evolution of the Tisza Mega-unit

Science.gov (United States)

Haas, János; Péró, Csaba

The south-eastern part of the basement of the Pannonian Basin is made up of Variscan crystalline complexes and early Mesozoic formations showing striking affinity with the corresponding formations in the southern margin of the European Plate. This large composite structural unit, which is actually an exotic terrane of European Plate origin, has been named the Tisza Mega-unit. Based upon relevant data of the pre-Tertiary basement of southern Hungary the reconstruction of the position of the Tisza Terrane in the early Alpine evolutionary stages, the process of its separation and break-off from the European Plate, and results of its Eo-Alpine deformations are summarised in the present paper. In the Variscan and early Alpine evolutionary stages the area of the later Tisza Mega-unit was located at the margin of the European Plate. During Variscan orogeny terrane accretion led to intensive deformation and metamorphism in this belt. This was followed by transpressional tectonics and the development of molasse basins in the late and post-Variscan stages, and passive margin evolution after the Neotethys opening in the Middle Triassic. The separation of the Tisza Mega-unit began with incipient continental rifting along the axis of the later Ligurian-Penninic-Vahic oceanic branch in the Late Triassic. The end of terrigenous material deposition in the most external zones, and a coeval change in fossil assemblage, point to the separation of the Tisza Block from the European Plate in the Early Bathonian. Significant rotation of the Tisza Mega-unit and coeval paroxysm of alkaline rift-type basalt volcanism took place in the Early Cretaceous. In the mid-Cretaceous, due to the northward motion of the Adria Block and the related closure of the westernmost Neotethys basin, the extensional regime changed to a compressional one, leading to onset of the nappe stacking and low-grade regional metamorphism within the Tisza microplate. In the foreland of the nappe systems flexural basins

Adenyl cyclases and cAMP in plant signaling - Past and present

KAUST Repository

Gehring, Christoph A.

2010-06-25

In lower eukaryotes and animals 3\\'-5\\'-cyclic adenosine monophosphate (cAMP) and adenyl cyclases (ACs), enzymes that catalyse the formation of cAMP from ATP, have long been established as key components and second messengers in many signaling pathways. In contrast, in plants, both the presence and biological role of cAMP have been a matter of ongoing debate and some controversy. Here we shall focus firstly on the discovery of cellular cAMP in plants and evidence for a role of this second messenger in plant signal transduction. Secondly, we shall review current evidence of plant ACs, analyse aspects of their domain organisations and the biological roles of candidate molecules. In addition, we shall assess different approaches based on search motifs consisting of functionally assigned amino acids in the catalytic centre of annotated and/or experimentally tested nucleotide cyclases that can contribute to the identification of novel candidate molecules with AC activity such as F-box and TIR proteins. 2010 Gehring; licensee BioMed Central Ltd.

Adenyl cyclases and cAMP in plant signaling - Past and present

KAUST Repository

Gehring, Christoph A

2010-01-01

In lower eukaryotes and animals 3'-5'-cyclic adenosine monophosphate (cAMP) and adenyl cyclases (ACs), enzymes that catalyse the formation of cAMP from ATP, have long been established as key components and second messengers in many signaling pathways. In contrast, in plants, both the presence and biological role of cAMP have been a matter of ongoing debate and some controversy. Here we shall focus firstly on the discovery of cellular cAMP in plants and evidence for a role of this second messenger in plant signal transduction. Secondly, we shall review current evidence of plant ACs, analyse aspects of their domain organisations and the biological roles of candidate molecules. In addition, we shall assess different approaches based on search motifs consisting of functionally assigned amino acids in the catalytic centre of annotated and/or experimentally tested nucleotide cyclases that can contribute to the identification of novel candidate molecules with AC activity such as F-box and TIR proteins. 2010 Gehring; licensee BioMed Central Ltd.

Understanding cAMP-dependent allostery by NMR spectroscopy: comparative analysis of the EPAC1 cAMP-binding domain in its apo and cAMP-bound states.

Science.gov (United States)

Mazhab-Jafari, Mohammad T; Das, Rahul; Fotheringham, Steven A; SilDas, Soumita; Chowdhury, Somenath; Melacini, Giuseppe

2007-11-21

cAMP (adenosine 3',5'-cyclic monophosphate) is a ubiquitous second messenger that activates a multitude of essential cellular responses. Two key receptors for cAMP in eukaryotes are protein kinase A (PKA) and the exchange protein directly activated by cAMP (EPAC), which is a recently discovered guanine nucleotide exchange factor (GEF) for the small GTPases Rap1 and Rap2. Previous attempts to investigate the mechanism of allosteric activation of eukaryotic cAMP-binding domains (CBDs) at atomic or residue resolution have been hampered by the instability of the apo form, which requires the use of mixed apo/holo systems, that have provided only a partial picture of the CBD apo state and of the allosteric networks controlled by cAMP. Here, we show that, unlike other eukaryotic CBDs, both apo and cAMP-bound states of the EPAC1 CBD are stable under our experimental conditions, providing a unique opportunity to define at an unprecedented level of detail the allosteric interactions linking two critical functional sites of this CBD. These are the phosphate binding cassette (PBC), where cAMP binds, and the N-terminal helical bundle (NTHB), which is the site of the inhibitory interactions between the regulatory and catalytic regions of EPAC. Specifically, the combined analysis of the cAMP-dependent changes in chemical shifts, 2 degrees structure probabilities, hydrogen/hydrogen exchange (H/H) and hydrogen/deuterium exchange (H/D) protection factors reveals that the long-range communication between the PBC and the NTHB is implemented by two distinct intramolecular cAMP-signaling pathways, respectively, mediated by the beta2-beta3 loop and the alpha6 helix. Docking of cAMP into the PBC perturbs the NTHB inner core packing and the helical probabilities of selected NTHB residues. The proposed model is consistent with the allosteric role previously hypothesized for L273 and F300 based on site-directed mutagenesis; however, our data show that such a contact is part of a

High current relativistic beam propagates stably in gas surrounded by nonconducting walls

International Nuclear Information System (INIS)

Clark, J.C.

1977-01-01

LLL has been studying the propagation of high current electron beams for a number of years to understand their behavior for use in a variety of experimental uses. Our latest experiments have shown that a mildly relativistic electron beam of 10 to 15 kA and a pulse width of 30 to 40 ns can propagate stably and with no net current transfer in insulating tubes filled with neutral gases. These experiments have been performed in the Magnetic Fusion Energy program where Electronics Engineering has been operating an electron beam accelerator, designing some of the diagnostics, such as laser interferometers, and performing the experiments. This article briefly describes our experimental observations

Activity of cAMP-dependent protein kinases and cAMP-binding proteins of rat kidney cytosol during dehydration

International Nuclear Information System (INIS)

Zelenina, M.N.; Solenov, E.I.; Ivanova, L.N.

1985-01-01

The activity of cAMP-dependent protein kinases, the binding of cAMP, and the spectrum of cAMP-binding proteins in the cytosol of the renal papilla was studied in intact rats and in rats after 24 h on a water-deprived diet. It was found that the activation of protein kinases by 10 -6 M cAMP is significantly higher in the experimental animals than in the intact animals. In chromatography on DEAE-cellulose, the positions of the peaks of specific reception of cAMP corresponded to the peaks of the regulatory subunits of cAMP-dependent protein kinases of types I and II. In this case, in intact animals more than 80% of the binding activity was detected in peaks II, whereas in rats subjected to water deprivation, more than 60% of the binding was observed in peak I. The general regulatory activity of the cytosol was unchanged in the experimental animals in comparison with intact animals. It is suggested that during dehydration there is an induction of the synthesis of the regulatory subunit of type I cAMP-dependent protein kinase in the renal papilla

Progress of neutral beam R and D for plasma heating and current drive at JAERI

International Nuclear Information System (INIS)

Ohara, Y.

1995-01-01

Recent progress and future plans regarding development of a high power negative ion source at the Japan Atomic Energy Research Institute (JAERI) are described. The neutral beam injection system, which is expected to play an important role not only in plasma heating but also in the plasma current drive in the fusion reactor, requires a high power negative ion source which can produce negative deuterium ion beams with current of order 20A at energy above 1MeV. In order to realize such a high power negative ion beam, intensive research and development has been carried out at JAERI since 1984. The negative hydrogen ion beam current of 10A achieved in recent years almost equals the value required for the fusion reactor. With regard to the negative ion acceleration, a high current negative ion beam of 0.2A has been accelerated up to 350keV electrostatically. On the basis of this recent progress, two development plans have been initiated as an intermediate step towards the fusion reactor. One is to develop a 500keV, 10MW negative ion based neutral beam injection system for JT-60U to demonstrate the neutral beam current drive in a high density plasma. The other is to develop a 1MeV, 1A ion source to demonstrate high current negative ion acceleration up to 1MeV. On the basis of this research and development, an efficient and reactor relevant neutral beam injection system will be developed for an experimental fusion reactor such as the International Thermonuclear Experimental Reactor. ((orig.))

High beam current shut-off systems in the APS linac and low energy transfer line

International Nuclear Information System (INIS)

Wang, X.; Knott, M.; Lumpkin, A.

1994-01-01

Two independent high beam current shut-off current monitoring systems (BESOCM) have been installed in the APS linac and the low energy transport line to provide personnel safety protection in the event of acceleration of excessive beam currents. Beam current is monitored by a fast current transformer (FCT) and fully redundant supervisory circuits connected to the Access Control Interlock System (ACIS) for beam intensity related shutdowns of the linac. One FCT is located at the end of the positron linac and the other in the low energy transport line, which directs beam to the positron accumulator ring (PAR). To ensure a high degree of reliability, both systems employ a continuous self-checking function, which injects a test pulse to a single-turn test winding after each ''real'' beam pulse to verify that the system is fully functional. The system is designed to be fail-safe for all possible system faults, such as loss of power, open or shorted signal or test cables, loss of external trigger, malfunction of gated integrator, etc. The system has been successfully commissioned and is now a reliable part of the total ACIS

Test results from the MEGA experiment: A search for the rare decay of the muon to an electron and a gamma ray

International Nuclear Information System (INIS)

Jui, C.C.H.

1992-06-01

This thesis reports on recent progress of the MEGA experiment. MEGA is the latest in a series of muon decay experiments at the Los Alamos Meson Physics Facility. The primary goal of the group is to look for the lepton family number violating decay mode of μ + → e + γ with a branching ratio sensitivity of 3 x 10 -13 . The experiment employs an innovative two-arm magnetic spectrometer, where photons are converted into e + e - pairs within thin sheets of lead. This design maximizes rate capability, retains large solid angle, and suppresses the background to below experimental sensitivity. Both arms of the MEGA detector are state-of-the-art in design. The high-rate, low mass cylindrical MWPCs used in the positron arm are especially challenging. The fabrication of these chambers required many technical innovations, including precision-machined ceramic spacers, thin, inflatable cathode foils, and circular garlands made from annealed glass fibers. After several years of detector development, MEGA conducted a test run in 1990, where prototypes of various detector components were successfully tested in beam. A trial μ → eγ search was also conducted. Results from the positron chamber tests verified performance expectations in most respects. Within the limits of the tests, position and momentum resolutions are in good agreement with Monte Carlo simulations. The trial eγ search provided a much needed opportunity to test the detector system as a whole. No serious problems were uncovered in the search, which reached a sensitivity of 2.3 x 10 -7 in less than a day's running with an incomplete detector system severely limited in acceptance and efficiency. From these results, it is projected that a sensitivity of 5 x 10 -12 will be reached in 1992, to be improved to 3 x 10 -13 in 1993--94

WAVEGUIDE COUPLER KICK TO BEAM BUNCH AND CURRENT DEPENDENCY ON SRF CAVITIES

International Nuclear Information System (INIS)

Genfa Wu; Haipeng Wang; Charles Reece; Robert Rimmer

2008-01-01

JLAB SRF cavities employ waveguide type fundamental power couplers (FPC). The FPC design for the 7-cell upgrade cavities was optimized to minimize the dipole field kick. For continuous wave (CW) operation, the forwarding RF power will be at different magnitude to drive the different beam current and cavity gradient. This introduces some deviation from optimized FPC field for varying beam loading. This article analyzes the beam behavior both in centroid kick and head-tail kick under different beam loading conditions

Purification, characterization, and sequencing of novel antimicrobial peptides, Tu-AMP 1 and Tu-AMP 2, from bulbs of tulip (Tulipa gesneriana L.).

Science.gov (United States)

Fujimura, Masatoshi; Ideguchi, Mineo; Minami, Yuji; Watanabe, Keiichi; Tadera, Kenjiro

2004-03-01

Novel antimicrobial peptides (AMP), designated Tu-AMP 1 and Tu-AMP 2, were purified from the bulbs of tulip (Tulipa gesneriana L.) by chitin affinity chromatography and reverse-phase high-performance liquid chromatography (HPLC). They bind to chitin in a reversible way. They were basic peptides having isoelectric points of over 12. Tu-AMP 1 and Tu-AMP 2 had molecular masses of 4,988 Da and 5,006 Da on MALDI-TOF MS analysis, and their extinction coefficients of 1% aqueous solutions at 280 nm were 3.3 and 3.4, respectively. Half of all amino acid residues of Tu-AMP 1 and Tu-AMP 2 were occupied by cysteine, arginine, lysine, and proline. The concentrations of peptides required for 50% inhibition (IC(50)) of the growth of plant pathogenic bacteria and fungi were 2 to 20 microg/ml. The structural characteristics of Tu-AMP 1 and Tu-AMP 2 indicated that they were novel thionin-like antimicrobial peptides, though Tu-AMP 2 was a heterodimer composes of two short peptides joined with disulfide bonds.

Limiting currents of an unneutralized magnetized electron beam in a cylindrical drift tube

International Nuclear Information System (INIS)

Thompson, J.R.; Sloan, M.L.

1978-01-01

Results of an investigation of the steady state injection of a uniform unneutralized, magnetized, relativistic electron beam into a cylindrical drift tube are presented. The space-charge-limited current and the asymptotic kinetic energy of electrons on axis is determined both numerically and analytically as a function of the input kinetic energy (γ 0 -1) mc 2 and of the ratio of beam-to-wall radii. A previously cited ''interpolation formula'' is obtained in the pencil beam limit, but more accurate limiting current expressions are developed for other cases (such as the fat beam limit) where the interpolation formula is as much as 20% in error. The corresponding axial electron energy is also found to be significantly smaller than the previously cited value of (γ/sup 1/3/ 0 -1) mc 2 except in the strong pencil beam limit

Parole, Sintagmatik, dan Paradigmatik Motif Batik Mega Mendung

Directory of Open Access Journals (Sweden)

Rudi - Nababan

2012-04-01

Full Text Available ABSTRACT   Discussing traditional batik is related a lot to the organization system of fine arts element ac- companying it, either the pattern of the motif or the technique of the making. In this case, the motif of Mega Mendung Cirebon certainly has patterns and rules which are traditionally different from the other motifs in other areas. Through  semiotics analysis especially with Saussure and Pierce concept, it can be traced that batik with Cirebon motif, in this case Mega Mendung motif, has parole and langue system, as unique fine arts language in batik, and structure of visual syntagmatic and paradigmatic. In the context of batik motif as fine arts language, it is surely related to sign system as symbol and icon.       Keywords: visual semiotic, Cirebon’s batik.

Optical fiber Cherenkov detector for beam current monitoring

International Nuclear Information System (INIS)

Pishchulin, I.V.; Solov'ev, N.G.; Romashkin, O.B.

1991-01-01

The results obtained in calculation of an optical fiber Cherenkov detector for accelerated beam current monitoring are presented. The technique of beam parameters monitoring is based on Cherenkov radiation excitation by accelerated electrons in the optical fiber. The formulas for calculations of optical power and time dependence of Cherenkov radiation pulse are given. The detector sensitivity and time resolution dependence on the fiber material characteristics are investigated. Parameters of a 10μm one-mode quartz optical fiber detector for the free electron laser photoinjector are calculated. The structure of a monitoring system with the optical fiber Cherenkov detector is considered. Possible applications of this technique are discussed and some recommendations are given

Mega Tsunamis of the World Ocean and Their Implication for the Tsunami Hazard Assessment

Science.gov (United States)

Gusiakov, V. K.

2014-12-01

Mega tsunamis are the strongest tsunamigenic events of tectonic origin that are characterized by run-up heights up to 40-50 m measured along a considerable part of the coastline (up to 1000 km). One of the most important features of mega-tsunamis is their ability to cross the entire oceanic basin and to cause an essential damage to its opposite coast. Another important feature is their ability to penetrate into the marginal seas (like the Sea of Okhotsk, the Bering Sea) and cause dangerous water level oscillations along the parts of the coast, which are largely protected by island arcs against the impact of the strongest regional tsunamis. Among all known historical tsunamis (nearly 2250 events during the last 4000 years) they represent only a small fraction (less than 1%) however they are responsible for more than half the total tsunami fatalities and a considerable part of the overall tsunami damage. The source of all known mega tsunamis is subduction submarine earthquakes with magnitude 9.0 or higher having a return period from 200-300 years to 1000-1200 years. The paper presents a list of 15 mega tsunami events identified so far in historical catalogs with their basic source parameters, near-field and far-field impact effects and their generation and propagation features. The far-field impact of mega tsunamis is largely controlled by location and orientation of their earthquake source as well as by deep ocean bathymetry features. We also discuss the problem of the long-term tsunami hazard assessment when the occurrence of mega tsunamis is taken into account.

Open-loop correction for an eddy current dominated beam-switching magnet.

Science.gov (United States)

Koseki, K; Nakayama, H; Tawada, M

2014-04-01

A beam-switching magnet and the pulsed power supply it requires have been developed for the Japan Proton Accelerator Research Complex. To switch bunched proton beams, the dipole magnetic field must reach its maximum value within 40 ms. In addition, the field flatness should be less than 5 × 10(-4) to guide each bunched beam to the designed orbit. From a magnetic field measurement by using a long search coil, it was found that an eddy current in the thick endplates and laminated core disturbs the rise of the magnetic field. The eddy current also deteriorates the field flatness over the required flat-top period. The measured field flatness was 5 × 10(-3). By using a double-exponential equation to approximate the measured magnetic field, a compensation pattern for the eddy current was calculated. The integrated magnetic field was measured while using the newly developed open-loop compensation system. A field flatness of less than 5 × 10(-4), which is an acceptable value, was achieved.

Mega-Amp Opening Switch with Nested Electrodes/Pulsed Generator of Ion and Ion Cluster Beams.

Science.gov (United States)

1985-07-01

i.e., noncollisiona].) resistivity which controls the "~switch opening" function (specifically, the rate of disintergration of the PF pinch where...unaffected the pinch field Be and then disassemble in a light (D) component and other heavy components. Production and propagation of-neutrals (from...emission, production and - evaporation would imply a distorsion of the pinholeimage-because of B -which is not p.-.. observed (our pinhole resolution is 150

Functional desensitization to isoproterenol without reducing cAMP production in canine failing cardiocytes.

Science.gov (United States)

Laurent, C E; Cardinal, R; Rousseau, G; Vermeulen, M; Bouchard, C; Wilkinson, M; Armour, J A; Bouvier, M

2001-02-01

To corroborate alterations in the functional responses to beta-adrenergic receptor (beta-AR) stimulation with changes in beta-AR signaling in failing cardiomyocytes, contractile and L-type Ca(2+) current responses to isoproterenol along with stimulated cAMP generation were compared among cardiomyocytes isolated from canines with tachycardia-induced heart failure or healthy hearts. The magnitude of shortening of failing cardiomyocytes was significantly depressed (by 22 +/- 4.4%) under basal conditions, and the maximal response to isoproterenol was significantly reduced (by 45 +/- 18%). Similar results were obtained when the responses in the rate of contraction and rate of relaxation to isoproterenol were considered. The L-type Ca(2+) current amplitude measured in failing cardiomyocytes under basal conditions was unchanged, but the responses to isoproterenol were significantly reduced compared with healthy cells. Isoproterenol-stimulated cAMP generation was similar in sarcolemmal membranes derived from the homogenates of failing (45 +/- 6.8) and healthy cardiomyocytes (52 +/- 8.5 pmol cAMP. mg protein(-1). min(-1)). However, stimulated cAMP generation was found to be significantly reduced when the membranes were derived from the homogenates of whole tissue (failing: 67 +/- 8.1 vs. healthy: 140 +/- 27.8 pmol cAMP. mg protein(-1). min(-1)). Total beta-AR density was not reduced in membranes derived from either whole tissue or isolated cardiomyocyte homogenates, but the beta(1)/beta(2) ratio was significantly reduced in the former (failing: 45/55 vs. healthy: 72/28) without being altered in the latter (failing: 72/28, healthy: 77/23). We thus conclude that, in tachycardia-induced heart failure, reduction in the functional responses of isolated cardiomyocytes to beta-AR stimulation may be attributed to alterations in the excitation-contraction machinery rather than to limitation of cAMP generation.

Macrofilament simulation of high current beam transport

International Nuclear Information System (INIS)

Hayden, R.J.; Jakobson, M.J.

1985-01-01

Macrofilament simulation of high current beam transport through a series of solenoids has been used to investigate the sensitivity of such calculations to the initial beam distribution and to the number of filaments used in the simulation. The transport line was tuned to approximately 105 0 phase advance per cell at zero current with a tune depression of 65 0 due to the space charge. Input distributions with the filaments randomly uniform throughout a four dimensional ellipsoid and K-V input distributions have been studied. The behavior of the emittance is similar to that published for quadrupoles with like tune depression. The emittance demonstrated little growth in the first twelve solenoids, a rapid rate of growth for the next twenty, and a subsequent slow rate of growth. A few hundred filaments were sufficient to show the character of the instability. The number of filaments utilized is an order of magnitude fewer than has been utilized previously for similar instabilities. The previously published curves for simulations with less than a thousand particles show a rather constant emittance growth. If the solenoid transport line magnetic field is increased a few percent, emittance growth curves are obtained not unlike those curves. Collision growth effects are less important than indicated in the previously published results for quadrupoles

Novel Faraday cup for the simultaneous observation and measurement of ion-beam currents

International Nuclear Information System (INIS)

Wei, C.; Seidman, D.N.

1977-01-01

A novel Faraday cup is described which allows the simultaneous observation and measurement of ion-beam currents. The Faraday cup is constructed around a Galileo channel electron multiplier array (CEMA), which serves as the basis of an internal image intensification system (a gain of >10 4 ) for the observation of the ion beam; the CEMA also acts as a collector for the ion current which is measured by a Keithley 602 electrometer. The ion current is integrated by a simple and inexpensive dosimeter; the electronic circuit for the dosimeter is described. The application of the Faraday cup to the observation and measurement of a 30-keV Ar + ion beam is presented as an illustrative example. We have also employed this Faraday cup to observe and measure 30-keV Cr + , Mo + , or W + , and 18-keV Au + ion beams employed for the in situ irradiation of field-ion microscope specimens

Beam position monitor data acquisition for the Advanced Photon Source

International Nuclear Information System (INIS)

Lenkszus, F.R.; Kahana, E.; Votaw, A.J.; Decker, G.A.; Chung, Y.; Ciarlette, D.J.; Laird, R.J.

1993-01-01

This paper describes the Beam Position Monitor (BPM) data acquisition scheme for the Advanced Photon Source (APS) storage ring. The storage ring contains 360 beam position monitors distributed around its 1104-meter circumference. The beam position monitor data acquisition system is capable of making turn-by-turn measurements of all BPMs simultaneously. It is VXI-based with each VXI crate containing the electronics for 9 BPMS. The VXI Local Bus is used to provide sustained data transfer rates of up to 13 mega-transfers per second to a scanner module. The system provides single-bunch tracking, bunch-to-bunch measurements, fast digital-averaged positions, beam position history buffering, and synchronized multi-turn measurements. Data is accessible to the control system VME crates via an MXI bus. Dedicated high-speed ports are provided to supply position data to beam orbit feedback systems

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

International Nuclear Information System (INIS)

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

2009-01-01

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

Applicability evaluation of eddy current testing for underwater laser beam welding

International Nuclear Information System (INIS)

Kobayashi, Noriyasu; Kasuya, Takashi; Ueno, Souichi; Ochiai, Makoto; Yuguchi, Yasuhiro

2010-01-01

We clarified a defect detecting capability of eddy current testing (ECT) as a surface inspection technique for underwater laser beam welding. An underwater laser beam welding procedure includes groove caving as a preparation, laser beam welding in groove and welding surface grinding as a post treatment. Therefore groove and grinded welding surface inspections are required underwater. We curried out defect detection tests using three kinds of specimens simulated a groove, reactor vessel nozzle dissimilar metal welding materials and a laser beam welding material with a cross coil ECT probe. From experimental results, we confirmed that it is possible to detect 0.3 mm or more depth electro-discharge machining slits on machining surfaces in all specimens and an ECT has possibility as a surface inspection technique for underwater laser beam welding. (author)

Small-sized monitor of beam current and profile for the proton pulse electrostatic accelerator

International Nuclear Information System (INIS)

Getmanov, V.N.

1985-01-01

Design and principle of operation of current monitor and beam profile of range-coordinate type are described. Monitor operation peculiarities are discussed using diagnostics of a beam of 330-420 keV electrostatic pulse proton accelerator with a beam current of up to 20 mA, at a current density of up to 23 mA x cm -2 and wth pulse duraton of about 20 μs. The monitor consists of a vacuum-dense foil of 3.0+-0.1 μm in thickness (or 0.81+-0.0x- mg x cm -2 ) two grid electrodes, each containing 12 wires, and as solid copper bottom. Foil serves for chopping off background particles with a path lesser 3.0 μm and stands thermal pulse load up to 0.5 J/cm -2 . Grid electrode wires are oriented perpendicularly to lach other and form a two-coordinate secondary-emisson roughness indicator. The bothhom is used for measuring an absolute value of beam current

Calcium pathways such as cAMP modulate clothianidin action through activation of α-bungarotoxin-sensitive and -insensitive nicotinic acetylcholine receptors.

Science.gov (United States)

Calas-List, Delphine; List, Olivier; Quinchard, Sophie; Thany, Steeve H

2013-07-01

Clothianidin is a neonicotinoid insecticide developed in the early 2000s. We have recently demonstrated that it was a full agonist of α-bungarotoxin-sensitive and -insensitive nicotinic acetylcholine receptors expressed in the cockroach dorsal unpaired median neurons. Clothianidin was able to act as an agonist of imidacloprid-insensitive nAChR2 receptor and internal regulation of cAMP concentration modulated nAChR2 sensitivity to clothianidin. In the present study, we demonstrated that cAMP modulated the agonist action of clothianidin via α-bungarotoxin-sensitive and insensitive receptors. Clothianidin-induced current-voltage curves were dependent to clothianidin concentrations. At 10 μM clothianidin, increasing cAMP concentration induced a linear current-voltage curve. Clothianidin effects were blocked by 0.5 μM α-bungarotoxin suggesting that cAMP modulation occurred through α-bungarotoxin-sensitive receptors. At 1 mM clothianidin, cAMP effects were associated to α-bungarotoxin-insensitive receptors because clothianidin-induced currents were blocked by 5 μM mecamylamine and 20 μM d-tubocurarine. In addition, we found that application of 1mM clothianidin induced a strong increase of intracellular calcium concentration. These data reinforced the finding that calcium pathways including cAMP modulated clothianidin action on insect nicotinic acetylcholine receptors. We proposed that intracellular calcium pathways such as cAMP could be a target to modulate the mode of action of neonicotinoid insecticides. Copyright © 2013 Elsevier Inc. All rights reserved.

21 CFR 862.1230 - Cyclic AMP test system.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cyclic AMP test system. 862.1230 Section 862.1230....1230 Cyclic AMP test system. (a) Identification. A cyclic AMP test system is a device intended to measure the level of adenosine 3′, 5′-monophosphate (cyclic AMP) in plasma, urine, and other body fluids...

Nano-electron beam induced current and hole charge dynamics through uncapped Ge nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Marchand, A.; El Hdiy, A.; Troyon, M. [Laboratoire de Recherche en Nanosciences, Bat. 6, case no 15, UFR Sciences, Universite de Reims Champagne Ardenne, 51687 Reims Cedex 2 (France); Amiard, G.; Ronda, A.; Berbezier, I. [IM2NP, Faculte des Sciences et Techniques, Campus de Saint Jerome - Case 142, Avenue Escadrille Normandie Niemen, 13397 Marseille Cedex 20 (France)

2012-04-16

Dynamics of hole storage in spherical Ge nanocrystals (NCs) formed by a two step dewetting/nucleation process on an oxide layer grown on an n-doped <001> silicon substrate is studied using a nano-electron beam induced current technique. Carrier generation is produced by an electron beam irradiation. The generated current is collected by an atomic force microscope--tip in contact mode at a fixed position away from the beam spot of about 0.5 {mu}m. This distance represents the effective diffusion length of holes. The time constants of holes charging are determined and the effect of the NC size is underlined.

In situ beam angle measurement in a multi-wafer high current ion implanter

International Nuclear Information System (INIS)

Freer, B.S.; Reece, R.N.; Graf, M.A.; Parrill, T.; Polner, D.

2005-01-01

Direct, in situ measurement of the average angle and angular content of an ion beam in a multi-wafer ion implanter is reported for the first time. A new type of structure and method are described. The structures are located on the spinning disk, allowing precise angular alignment to the wafers. Current that passes through the structures is known to be within a range of angles and is detected behind the disk. By varying the angle of the disk around two axes, beam current versus angle is mapped and the average angle and angular spread are calculated. The average angle measured in this way is found to be consistent with that obtained by other techniques, including beam centroid offset and wafer channeling methods. Average angle of low energy beams, for which it is difficult to use other direct methods, is explored. A 'pencil beam' system is shown to give average angle repeatability of 0.13 deg. (1σ) or less, for two low energy beams under normal tuning variations, even though no effort was made to control the angle

Influence of total beam current on HRTEM image resolution in differentially pumped ETEM with nitrogen gas

International Nuclear Information System (INIS)

Bright, A.N.; Yoshida, K.; Tanaka, N.

2013-01-01

Environmental transmission electron microscopy (ETEM) enables the study of catalytic and other reaction processes as they occur with Angstrom-level resolution. The microscope used is a dedicated ETEM (Titan ETEM, FEI Company) with a differential pumping vacuum system and apertures, allowing aberration corrected high-resolution transmission electron microscopy (HRTEM) imaging to be performed with gas pressures up to 20 mbar in the sample area and with significant advantages over membrane-type E-cell holders. The effect on image resolution of varying the nitrogen gas pressure, electron beam current density and total beam current were measured using information limit (Young's fringes) on a standard cross grating sample and from silicon crystal lattice imaging. As expected, increasing gas pressure causes a decrease in HRTEM image resolution. However, the total electron beam current also causes big changes in the image resolution (lower beam current giving better resolution), whereas varying the beam current density has almost no effect on resolution, a result that has not been reported previously. This behavior is seen even with zero-loss filtered imaging, which we believe shows that the drop in resolution is caused by elastic scattering at gas ions created by the incident electron beam. Suitable conditions for acquiring high resolution images in a gas environment are discussed. Lattice images at nitrogen pressures up to 16 mbar are shown, with 0.12 nm information transfer at 4 mbar. -- Highlights: ► ETEM images with point resolution of 0.12 nm in 4 mbar of nitrogen gas. ► Clear Si lattice imaging with 16 mbar of nitrogen gas. ► ETEM image resolution in gas can be much improved by decreasing total beam current. ► Beam current density (beam convergence) has no effect on the image resolution.

Activation of PKA in cell requires higher concentration of cAMP than in vitro: implications for compartmentalization of cAMP signalling.

Science.gov (United States)

Koschinski, Andreas; Zaccolo, Manuela

2017-10-26

cAMP is a ubiquitous second messenger responsible for the cellular effects of multiple hormones and neurotransmitters via activation of its main effector, protein kinase A (PKA). Multiple studies have shown that the basal concentration of cAMP in several cell types is about 1 μM. This value is well above the reported concentration of cAMP required to half-maximally activate PKA, which measures in the 100-300 nM range. Several hypotheses have been suggested to explain this apparent discrepancy including inaccurate measurements of intracellular free cAMP, inaccurate measurement of the apparent activation constant of PKA or shielding of PKA from bulk cytosolic cAMP via localization of the enzyme to microdomains with lower basal cAMP concentration. However, direct experimental evidence in support of any of these models is limited and a firm conclusion is missing. In this study we use multiple FRET-based reporters for the detection of cAMP and PKA activity in intact cells and we establish that the sensitivity of PKA to cAMP is almost twenty times lower when measured in cell than when measured in vitro. Our findings have important implications for the understanding of compartmentalized cAMP signalling.

Single-beam measurements of LHC instability threshold in terms of octupole current

CERN Document Server

Mounet, N; Buffat, X; Burov, A; Hemelsoet, G; Metral, E; Papotti, G; Pieloni, T; Pojer, M; Salvant, B; Trad, G

2012-01-01

This note summarizes two machine development (MD) studies aimed at determining the octupole current needed in the LHC in order to stabilize all headtail instabilities at 4TeV/c, before and after the squeeze, with tight collimator settings, and when a single beam (beam 2) at maximum intensity (1380 bunches, 2.1 1014 protons) is present in the machine. The MDs followed the normal physics operation procedure, at the notable exception that a single beam was used, the other beam containing only one non-colliding nominal bunch. Octupole current (with negative polarity in the focusing octupoles and the opposite in the defocusing ones) was decreased by small steps until the instability threshold was reached. This was performed in two distinct MDs, one before the squeeze and the other after it, testing also several chromaticity values and the effect of the transverse damper in the latter case. Octupole thresholds are shown in each case studied, as well as the rise times of the instabilities observed.

Proteomic signatures implicate cAMP in light and temperature responses in Arabidopsis thaliana

KAUST Repository

Thomas, Ludivine

2013-05-01

The second messenger 3\\'-5\\'-cyclic adenosine monophosphate (cAMP) and adenylyl cyclases (ACs), enzymes that catalyse the formation of cAMP from ATP, are increasingly recognized as important signaling molecules in a number of physiological responses in higher plants. Here we used proteomics to identify cAMP-dependent protein signatures in Arabidopsis thaliana and identify a number of differentially expressed proteins with a role in light- and temperature-dependent responses, notably photosystem II subunit P-1, plasma membrane associated cation-binding protein and chaperonin 60 β. Based on these proteomics results we conclude that, much like in cyanobacteria, algae and fungi, cAMP may have a role in light signaling and the regulation of photosynthesis as well as responses to temperature and we speculate that ACs could act as light and/or temperature sensors in higher plants. Biological significance: This current study is significant since it presents the first proteomic response to cAMP, a novel and key second messenger in plants. It will be relevant to researchers in plant physiology and in particular those with an interest in second messengers and their role in biotic and abiotic stress responses. © 2013 Elsevier B.V.

Astrocyte mega-domain hypothesis of the autistic savantism.

Science.gov (United States)

Mitterauer, Bernhard J

2013-01-01

Individuals with autism who show high abilities are called savants. Whereas in their brains a disconnection in and between neural networks has been identified, savantism is yet poorly understood. Focusing on astrocyte domain organization, it is hypothesized that local astrocyte mega-organizations may be responsible for exerting high capabilities in brains of autistic savants. Astrocytes, the dominant glial cell type, modulate synaptic information transmission. Each astrocyte is organized in non-overlapping domains. Formally, each astrocyte contacting n-neurons with m-synapses via its processes generates dynamic domains of synaptic interactions based on qualitative computation criteria, and hereby it structures neuronal information processing. If the number of processes is genetically significantly increased, these astrocytes operate in a mega-domain with a higher complexitiy of computation. From this model savant abilities are deduced. Copyright © 2012 Elsevier Ltd. All rights reserved.

Neutronics design of accelerator-driven system for power flattening and beam current reduction

International Nuclear Information System (INIS)

Nishihara, Kenji; Iwanaga, Kohei; Tsujimoto, Kazufumi; Kurata, Yuji; Oigawa, Hiroyuki; Iwasaki, Tomohiko

2008-01-01

In the present neutronics design of the Accelerator-Driven System (ADS) cooled by lead-bismuth eutectic (LBE), we investigated several methods to reduce the power peak and beam current, and estimated the temperature reductions of the cladding tube and beam window from the conventional design. The methods are adjustment of inert matrix ratio in fuel in each burn-up cycle, multiregion design in terms of pin radius or inert matrix content, and modification of the level of the beam window position and the height of the central fuel assemblies. As a result, we optimized the ADS combined with the adjustment of the inert matrix ratio in each burn-up cycle, multiregion design in terms of inert matrix content and deepened window level. The maximum temperatures of the optimized ADS at the surface of the cladding tube and the beam window were reduced by 91 and 38degC, respectively. The maximum beam current was improved from 20.3 to 15.6 mA. (author)

Bridge Approach Remedies Implemented at Western Mega Site

Science.gov (United States)

2017-09-01

As part of the heavy axle load (HAL) revenue service mega site testing program, the Transportation Technology Center, Inc. (TTCI) has worked closely with the Union Pacific Railroad (UP) to address bridge approach problems under HAL operations. The te...

Current control of the electron beam formed in the magnetron gun with a secondary-emission cathode

International Nuclear Information System (INIS)

Dovbnya, A.N.; Reshetnyak, N.G.; Zakutin, V.V.; Chertishchev, I.A.; Romas'ko, V.P.; Dovbnyan, N.A.

2013-01-01

Data are reported on electron beam generation and beam current control in two types of secondary-emission cathode magnetron guns. The influence of the magnetic field value and field distribution on the formation of the beam and its parameters has been investigated in the electron energy range between 20 and 150 keV. The influence of local magnetic field variations on the cathode and the electron beam characteristics has been studied. The possibility to control the electron beam current in various ways has been demonstrated

Inhibitory action of certain cyclophosphate derivatives of cAMP on cAMP-dependent protein kinases

NARCIS (Netherlands)

Wit, René J.W. de; Hekstra, Doeke; Jastorff, Bernd; Stec, Wojciech J.; Baraniak, Janina; Driel, Roel van; Haastert, Peter J.M. van

1984-01-01

A series cAMP derivatives with modifications in the adenine, ribose and cyclophosphate moiety were screened for their binding affinity for the two types of cAMP-binding sites in mammalian protein kinase type I. In addition, the activation of the kinase by these analogs was monitored. The binding

Cancellation of OpAmp virtual ground imperfections by a negative conductance applied to improve RF receiver linearity

NARCIS (Netherlands)

Mahrof, D.H.; Klumperink, Eric A.M.; Ru, Z.; Oude Alink, M.S.; Nauta, Bram

2014-01-01

High linearity CMOS radio receivers often exploit linear V-I conversion at RF, followed by passive down-mixing and an OpAmp-based Transimpedance Amplifier at baseband. Due to nonlinearity and finite gain in the OpAmp, virtual ground is imperfect, inducing distortion currents. This paper proposes a

Disruptive Innovation Patterns Driven by Mega-Projects: A Sustainable Development Pattern Case of China’s High-Speed Rail

Directory of Open Access Journals (Sweden)

Bingxiu Gui

2018-04-01

Full Text Available Sustainable development of mega-projects has drawn many concerns around the world. The theory of disruptive innovation in mega-projects is a typical sustainable development pattern but still lacks systematic understanding. This article takes China’s high-speed rail (CHSR project as an example to analyze the disruptive innovation pattern of mega-projects. First, this paper systematically traces the theories of disruptive innovation and summarizes the connotations of disruptive innovation. Simultaneously, from the historical development of several typical mega-projects in China, this paper summarizes the connotations of mega-projects. Based on two connotations, this paper summarizes the theoretical basis of disruptive innovation in mega-projects. Second, this paper takes the CHSR project as a case to analyze its innovation pattern from the analysis of the development process, operation mechanism and influence in sustainability; the disruptive innovation pattern is put forward afterward. Third, the discussion is drawn from the perspectives of the characteristics, scope of application and innovation environment of the disruptive innovation of CHSR. Last, the conclusions of this article are summarized.

Proceedings of the 1979 workshop on beam current limitations in storage rings, July 16-27, 1979

International Nuclear Information System (INIS)

Pellegrini, C.

1979-01-01

The Workshop on Beam Current Limitations in Storage Rings was held at Brookhaven National Laboratory from July 16 to 27, 1979. The purpose of this Workshop was to discuss the physical mechanisms limiting the beam current or current density in accelerators or storage rings. Many of these machines are now being built or planned for a variety of applications, such as colliding beam experiments, synchrotron light production, heavy ion beams. This diversity was reflected in the Workshop and in the papers which have been contributed to these Proceedings. The twenty-one papers from the workshop were incorporated individually in the data base

Development of movable mask system to cope with high beam current

International Nuclear Information System (INIS)

Suetsugu, Y.; Shibata, K.; Sanami, T.; Kageyama, T.; Takeuchi, Y.

2003-01-01

The KEK B factory (KEKB), a high current electron-positron collider, has a movable mask (or collimator) system to reduce the background noise in the BELLE detector coming from spent particles. The early movable masks, however, had severe problems of heating, arcing, and vacuum leaks over the stored beam current of several hundred mA. The cause is intense trapped higher order modes (HOMs) excited at the mask head, where the cross section of the beam chamber changed drastically. The mask head, made of copper-tungsten alloy or pure copper, was frequently damaged by hitting of the high energy beam at the same time. Since the problems of the mask were revealed, several kinds of improved masks have been designed employing rf technologies in dealing with the HOM and installed to the ring step by step. Much progress has come from adopting a trapped-mode free structure, where the mask was a bent chamber itself. Recently the further improved mask with a reduced HOM design or HOM dampers was developed to suppress the heating of vacuum components near the mask due to the HOM traveling from the mask. To avoid damage to the mask head, on the other hand, a titanium mask head was tried. The latest masks are working as expected now at the stored beam current of 1.5 A. Presented are the problems and experiences on the movable mask system for the KEKB, which are characteristic of and common in a high intensity accelerator

The Mega-MUSCLES HST Treasury Survey

Science.gov (United States)

Froning, Cynthia S.; France, Kevin; Loyd, R. O. Parke; Youngblood, Allison; Brown, Alexander; Schneider, Christian; Berta-Thompson, Zachory; Kowalski, Adam

2018-01-01

JWST will be able to observe the atmospheres of rocky planets transiting nearby M dwarfs. A few such planets are already known (around GJ1132, Proxima Cen, and Trappist-1) and TESS is predicted to find many more, including ~14 habitable zone planets. To interpret observations of these exoplanets' atmospheres, we must understand the high-energy SED of their host stars: X-ray/EUV irradiation can erode a planet's gaseous envelope and FUV/NUV-driven photochemistry shapes an atmosphere's molecular abundances, including potential biomarkers like O2, O3, and CH4. Our MUSCLES Treasury Survey (Cycles 19+22) used Hubble/COS+STIS UV observations with contemporaneous X-ray and ground-based data to construct complete SEDs for 11 low-mass exoplanet hosts. MUSCLES is the most widely used database for early-M and K dwarf (>0.3 M_sun) irradiance spectra and has supported a wide range of atmospheric stability and biomarker modeling work. However, TESS will find most of its habitable planets transiting stars less massive than this, and these will be the planets to characterize with JWST. Here, we introduce the Mega-MUSCLES project, an approved HST Cycle 25 Treasury program. Following on the successful MUSCLES survey, Mega-MUSCLES will expand our target list to focus on: (a) new M dwarf exoplanet hosts with varying properties; (b) reference M dwarfs below 0.3 solar masses that may be used as proxies for M dwarf planet hosts discovered after HST's lifetime; and (c) more rapidly rotating stars of GJ1132's mass to probe XUV evolution over gigayear timescales. We will also gather the first panchromatic SEDs of rocky planet hosts GJ1132 and Trappist-1. Here, we present an overview of the Mega-MUSCLES motivation, targets list, and status of the survey and show how it extends proven methods to a key new sample of stars, upon which critically depends the long-term goal of studying habitable planet atmospheres with JWST and beyond.

Improvement of bunch-by-bunch beam current detection system in Hefei light source

International Nuclear Information System (INIS)

Zheng Kai; Wang Junhua; Liu Zuping; Li Weimin; Zhou Zeran; Yang Yongliang; Huang Longjun; Chen Yuanbo

2006-01-01

Bunch-by-bunch beam current detection system is an important facility in the multibunch storage ring. In this paper, the established bunch-by-bunch beam current detection systems for the accelerator such as Cornell, SLAC and KEKB were compared and studied. The design of the bunch-by-bunch beam current detection system for HLS, which was based on the bunch-by-bunch tracing measurement system in HLS was given. Both demodulation by sine wave and square were applied in this paper, the deviation of the detect system was determined by the longitudinal oscillation. Compared the data acquired from ADC with the data from DCCT, the ADC data was scaled by the bunch current. The standard deviations of linear fit were about 1%, and the standard deviations of polynomial fit were less than 0.5% in both sine wave and square wave demodulation. Some analysis of the measurement results also had been shown in this paper. (authors)

Current status and future prospect of electron beam sterilization in Japan

International Nuclear Information System (INIS)

Katsura, Ichiro

1998-01-01

It seems that electron beam sterilization is being current topic among all applications in Japan and that this tendency will continue until when major companies interested in the technology complete introducing electron beam. Since the Ministry of Health and Welfare(MOHW) officially issued revised regulation on GMP for medical devices in 1995, EtO has become the method regarded as time and money consuming one. On the contrary, electron beam has become as relatively economical and desirable method to achieve same result by its characteristics such as high productivity, rather easy validation and consequent cost reduction, although less penetration limit the kind of products to be treated. Status and prospect of electron beam sterilization in Japan will be presented in the paper along with accelerator related technologies

Cyclic AMP Inhibits the Activity and Promotes the Acetylation of Acetyl-CoA Synthetase through Competitive Binding to the ATP/AMP Pocket.

Science.gov (United States)

Han, Xiaobiao; Shen, Liqiang; Wang, Qijun; Cen, Xufeng; Wang, Jin; Wu, Meng; Li, Peng; Zhao, Wei; Zhang, Yu; Zhao, Guoping

2017-01-27

The high-affinity biosynthetic pathway for converting acetate to acetyl-coenzyme A (acetyl-CoA) is catalyzed by the central metabolic enzyme acetyl-coenzyme A synthetase (Acs), which is finely regulated both at the transcriptional level via cyclic AMP (cAMP)-driven trans-activation and at the post-translational level via acetylation inhibition. In this study, we discovered that cAMP directly binds to Salmonella enterica Acs (SeAcs) and inhibits its activity in a substrate-competitive manner. In addition, cAMP binding increases SeAcs acetylation by simultaneously promoting Pat-dependent acetylation and inhibiting CobB-dependent deacetylation, resulting in enhanced SeAcs inhibition. A crystal structure study and site-directed mutagenesis analyses confirmed that cAMP binds to the ATP/AMP pocket of SeAcs, and restrains SeAcs in an open conformation. The cAMP contact residues are well conserved from prokaryotes to eukaryotes, suggesting a general regulatory mechanism of cAMP on Acs. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

SU-F-T-554: Dark Current Effect On CyberKnife Beam Dosimetry

Energy Technology Data Exchange (ETDEWEB)

Kim, H; Chang, A [Soonchunhyang University Hospital, Seoul (Korea, Republic of)

2016-06-15

Purpose: All RF linear accelerators produce dark current to varying degrees when an accelerating voltage and RF input is applied in the absence of electron gun injection. This study is to evaluate how dark current from the linear accelerator of CyberKnife affect the dose in the reference dosimetry. Methods: The G4 CyberKnife system with 6MV photon beam was used in this study. Using the ion chamber and the diode detector, the dose was measured in water with varying time delay between acquiring charges and staring beam-on after applying high-voltage into the linear accelerator. The dose was measured after the time delay with over the range of 0 to 120 seconds in the accelerating high-voltage mode without beam-on, applying 0, 10, 50, 100, and 200 MUs. For the measurements, the collimator of 60 mm was used and the detectors were placed at the depths of 10 cm with the source-to-surface distance of 80 cm. Results: The dark current was constant over time regardless of MU. The dose due to the dark current increased over time linearly with the R-squared value of 0.9983 up to 4.4 cGy for the time 120 seconds. In the dose rate setting of 720 MU/min, the relative dose when applying the accelerating voltage without beam-on was increased over time up to 0.6% but it was less than the leakage radiation resulted from the accelerated head. As the reference dosimetry condition, when 100 MU was delivered after 10 seconds time delay, the relative dose increased by 0.7% but 6.7% for the low MU (10 MU). Conclusion: In the dosimetry using CyberKnife system, the constant dark current affected to the dose. Although the time delay in the accelerating high-voltage mode without beam-on is within 10 seconds, the dose less than 100 cGy can be overestimated more than 1%.

Comparison of mega-voltage cone-beam computed tomography prostate localization with online ultrasound and fiducial markers methods.

Science.gov (United States)

Gayou, Olivier; Miften, Moyed

2008-02-01

The online image-guided localization data from 696 ultrasound (US), 598 mega-voltage cone-beam computed tomography (MV-CBCT), and 393 seed markers (SMs) couch alignments for patients undergoing intensity modulation radiotherapy of the prostate were analyzed. Daily US, MV-CBCT and SM images were acquired for 19, 17 and 12 patients, respectively, after each patient was immobilized in a vacuum cradle and setup to skin markers as the center of mass. The couch shifts applied in the lateral (left-right/LR), vertical (anterior-posterior/AP), and longitudinal (superior-inferior/SI) directions, along with the magnitude of the three-dimensional (3D) shift vector, were analyzed and compared for all three methods. The percentage of shifts larger than 5 mm in all directions was also compared. Clinical target volume-planning target volume (CTV-to-PTV) expansion margins were estimated based on the localization data with US, CB, and SM image guidance. Results show the US data have greater variability. Systematic and random shifts were -1.2 +/- 6.8 mm (LR), -2.8 +/- 5.1 mm (SI) and -1.0 +/- 5.9 mm (AP) for US, 1.0 +/- 3.9 mm (LR), -1.3 +/- 2.5 mm (SI) and -0.3 +/- 3.9 mm (AP) for CB, and -1.0 +/- 3.4 mm (LR), 0.0 +/- 3.4 mm (SI) and 0.5 +/- 4.1 mm (AP) for SM. The mean 3D shift distance was larger using US (8.8 +/- 6.2 mm) compared to CB and SM (5.3 +/- 3.4 mm and 5.2 +/- 3.7 mm, respectively). The percentage of US shifts larger than 5 mm were 34%, 31%, and 38% in the LR, SI, and AP directions, respectively, compared to 18%, 6%, and 16% for CB and 14%, 10%, and 20% for SM. MV-CBCT and SM localization data suggest a different distribution of prostate center-of-mass shifts with smaller variability, compared to US. The online MV-CBCT and SM image-guidance data show that for treatments that do not include daily prostate localization, one can use a CTV-to-PTV margin that is 4 mm smaller than the one suggested by US data, hence allowing more rectum and bladder sparing and potentially

Beam current monitoring in the AGS Booster and its transfer lines

International Nuclear Information System (INIS)

Witkover, R.L.; Zitvogel, E.; Castillo, V.

1991-01-01

The new AGS Booster is designed to accelerate low intensity polarized protons and heavy ions, and high intensity protons. The wide range of beam parameters and the vacuum, thermal and radiation environment, presented challenges in the instrumentation design. This paper describes the problems and solutions for the beam current monitors in the Booster and its transport lines. Where available, results of the initial operation will be presented. 11 refs., 3 figs

Beam Dynamics Studies and the Design, Fabrication and Testing of Superconducting Radiofrequency Cavity for High Intensity Proton Accelerator

Energy Technology Data Exchange (ETDEWEB)

Saini, Arun [Univ. of Delhi, New Delhi (India)

2012-03-01

The application horizon of particle accelerators has been widening significantly in recent decades. Where large accelerators have traditionally been the tools of the trade for high-energy nuclear and particle physics, applications in the last decade have grown to include large-scale accelerators like synchrotron light sources and spallation neutron sources. Applications like generation of rare isotopes, transmutation of nuclear reactor waste, sub-critical nuclear power, generation of neutrino beams etc. are next area of investigation for accelerator scientific community all over the world. Such applications require high beam power in the range of few mega-watts (MW). One such high intensity proton beam facility is proposed at Fermilab, Batavia, US, named as Project-X. Project-X facility is based on H^- linear accelerator (linac), which will operate in continuous wave (CW) mode and accelerate H^- ion beam with average current of 1 mA from kinetic energy of 2.5 MeV to 3 GeV to deliver 3MW beam power. One of the most challenging tasks of the Project-X facility is to have a robust design of the CW linac which can provide high quality beam to several experiments simultaneously. Hence a careful design of linac is important to achieve this objective.

Photon detector for MEGA

International Nuclear Information System (INIS)

Gagliardi, C.A.; Tribble, R.E.

1991-01-01

During the past year, we have continued work on the photon detector for the MEGA experiment at Los Alamos, a search for the rare decay μ → eγ to a sensitivity of a few parts in 10 13 . The MEGA photon detector is designed to observe the 52.38 MeV photon produced in a μ → eγ decay with an energy resolution of 1.25 MeV, a position resolution of 2 x 5 mm 2 , a directional resolution of 10 degrees, a time resolution of 500 ps, and an efficiency of 7%. It will consists of four independent concentric cylindrical pair spectrometers mounted within a 1.5 T magnetic field produced by a superconducting solenoid magnet. Each pair spectrometer includes two thin Pb foils to convert photons into e + e - pairs, and thereby, determine both their locations and their vector momenta. The inner drift chamber layer includes a delay line cathode to determine the z coordinates needed for track reconstruction. An MWPC located between two Pb layers identifies the conversion layer so that energy loss corrections may be applied, while plastic scintillators provide timing information. Our, group together with a group from the University of Houston, is responsible for the design and construction of the photon detector, as well as developing the computer codes necessary for Monte Carlo simulations and data analysis. During the past year, our efforts have focused primarily on two tasks, delay line cathode read-out and software development. This report describes our recent work on delay lines and data analysis along with a discussion of the new plans for multiplexing in the photon arm

Numerical simulation of the processes of small-diameter high-current electron beam shaping and injection

CERN Document Server

Gordeev, V S; Myskov, G A

2001-01-01

With the aid of BEAM 25 program there was carried out the numerical simulation of the non-stationary process of shaping a small-diameter (<= 20mm) high-current hollow electron beam in a diode with magnetic insulation,as well as of the process of beam injection into the accelerating LIA track. The diode configuration for the purpose of eliminating the leakage of electron flux to the anode surface was update. Presented are the results of calculation of the injected beam characteristics (amplitude-time parameters of a current pulse, space-angle distributions of electrons etc.) depending on diode geometric parameters.

Two-stream Stability Properties of the Return-Current Layer for Intense Ion Beam Propagation Through Background Plasma

International Nuclear Information System (INIS)

Startsev, Edward A.; Davidson, Ronald C.; Dorf, Mikhail

2009-01-01

When an ion beam with sharp edge propagates through a background plasma, its current is neutralized by the plasma return current everywhere except at the beam edge over a characteristic transverse distance Δx perpendicular ∼ (delta) pe , where (delta) pe = c/ω pe is the collisionless skin depth, and ω pe is the electron plasma frequency. Because the background plasma electrons neutralizing the ion beam current inside the beam are streaming relative to the background plasma electrons outside the beam, the background plasma can support a two-stream surface-mode excitation. Such surface modes have been studied previously assuming complete charge and current neutralization, and have been shown to be strongly unstable. In this paper we study the detailed stability properties of this two-stream surface mode for an electron flow velocity profile self-consistently driven by the ion beam. In particular, it is shown that the self-magnetic field generated inside the unneutralized current layer, which has not been taken into account previously, completely eliminates the instability

Radiation hydrodynamics of z-pinch plasmas

International Nuclear Information System (INIS)

Davis, J.

1993-01-01

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

Beam instability during high-current heavy-ion beam transport

International Nuclear Information System (INIS)

Kikuchi, T.; Someya, T.; Kawata, S.; Nakajima, M.; Horioka, K.

2005-01-01

In driver system for heavy ion inertial fusion, beam dynamics is investigated by particle-in-cell simulations during final beam bunching. The particle simulations predict that the beam is transported with the localized transverse charge distribution induced by the strong space charge effect. The calculation results also show that the emittance growth during the longitudinal bunch compression for various particle distributions at the initial conditions and with two types of transverse focusing model, which are a continuous focusing and an alternating gradient focusing lattice configurations. (author)

A Four Channel Beam Current Monitor Data Acquisition System Using Embedded Processors

Energy Technology Data Exchange (ETDEWEB)

Wheat, Jr., Robert Mitchell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dalmas, Dale A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dale, Gregory E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2015-08-11

Data acquisition from multiple beam current monitors is required for electron accelerator production of Mo-99. A two channel system capable of recording data from two beam current monitors has been developed, is currently in use, and is discussed below. The development of a cost-effective method of extending this system to more than two channels and integrating of these measurements into an accelerator control system is the main focus of this report. Data from these current monitors is digitized, processed, and stored by a digital data acquisition system. Limitations and drawbacks with the currently deployed digital data acquisition system have been identified as have been potential solutions, or at least improvements, to these problems. This report will discuss and document the efforts we've made in improving the flexibility and lowering the cost of the data acquisition system while maintaining the minimum requirements.

La estrategia comunicacional en el sector mega-minero. Un estudio del caso La Alumbrera en Argentina

Directory of Open Access Journals (Sweden)

Julieta Godfrid

2016-06-01

Full Text Available En los últimos años se produjo en la Argentina una rápida expansión de la mega-minería a cielo abierto, lo que vino acompañado de un creciente aumento de la conflictividad socio-ambiental que cuestiona en profundidad las consecuencias de la actividad extractiva. En este contexto, las múltiples críticas a la mega-minería deslegitimaron profundamente la imagen del sector y de las empresas que llevan adelante este tipo de actividad. A partir de allí, las corporaciones mega-mineras se vieron frente a la necesidad de construir una nueva estrategia comunicacional integral que les permitiera mejorar su imagen y construir consenso en torno a la actividad. El presente trabajo indaga en torno a las nuevas estrategias comunicacionales del sector mega-minero que se llevan a cabo bajo el paradigma de la Responsabilidad Social Empresaria y el “marketing experiencial”. Para ello se trabaja a partir del estudio de caso del emprendimiento mega-minero más antiguo del país, la empresa La Alumbrera (Provincia de Catamarca.

Start-Up Mega Planning--A Case History

Science.gov (United States)

Forbes, Ronald; Forbes, Dylan; Hoskins, Peter

2005-01-01

Social Responsibility is becoming a key issue for organizations today. They talk about it and they make social contributions, but how do we know if anything is being achieved? A framework is required and has existed at least since 1992. Roger Kaufman's Mega Planning has slowly gathered momentum in organizations worldwide. For a faster take-up we…

Regulation of melanogenesis: the role of cAMP and MITF

Directory of Open Access Journals (Sweden)

Michał Otręba

2012-01-01

Full Text Available The article presents the melanogenesis pathway and the role of cyclic adenosine monophosphate (cAMP and microphthalmia transcription factor (MITF in regulation of this process. Products of melanogenesis are eu- and/or pheomelanins synthesized in a multistage process of tyrosine oxidation and polymerization. The conversions require the presence of tyrosinase (TYR, key enzyme, tyrosine hydroxylase isoform I (THI and tyrosinase related proteins (TRP1 and TRP2. Many types of signal molecules and transcription factors participate in regulation of melanin synthesis, but the most important are cAMP and MITF. cAMP is the second messenger in the intracellular signal cascade, which is synthesized from adenosine triphosphate (ATP by adenylyl cyclase, activated among others by the melanocortin receptor and the αS subunit of G protein. The signal molecule cAMP regulates MITF, TYR, THI, GTP-cyclohydroxylase I (GTP-CHI transcription and phenylalanine hydroxylase (PAH phosphorylation at Ser16 by protein kinase A (PKA. Mutations of genes encoding proteins belonging to the cAMP signal cascade may lead to McCune-Albright and Carney syndromes. MITF is one of the most important nuclear transcription factors regulating melanogenesis. Currently 10 isoforms of human MITF are known, but in melanocytes only MITF-M, MITF-Mdel, MITF-A and MITF-H occur. MITF transcription factor regulates melanogenesis by activation of tyrosinase, TRP1 and TRP2 transcription. It also affects expression of other factors regulating melanosome maturation, biogenesis and transport. Moreover, it regulates melanocyte proliferation and protection against apoptosis. Mutations of the MITF gene may lead to hereditary diseases: Waardenburg type II and Tietz syndromes.

Local meanings of a sport mega-event's legacies : Stories from a South African urban neighbourhood

NARCIS (Netherlands)

Waardenburg, Maikel; van den Bergh, Marjolein; van Eekeren, Frank

2015-01-01

Studies on sport mega-events and their legacies often seem only loosely connected to local experiences. Stories on sport mega-event legacy appear as a setting-the-scene or function as a reference to illustrate specific types of legacy. However, stories themselves are never the primary focus in these

The CytR repressor antagonizes cyclic AMP-cyclic AMP receptor protein activation of the deoCp2 promoter of Escherichia coli K-12

DEFF Research Database (Denmark)

Søgaard-Andersen, L; Martinussen, J; Møllegaard, N E

1990-01-01

We have investigated the regulation of the Escherichia coli deoCp2 promoter by the CytR repressor and the cyclic AMP (cAMP) receptor protein (CRP) complexed to cAMP. Promoter regions controlled by these two proteins characteristically contain tandem cAMP-CRP binding sites. Here we show that (i) Cyt...

Magnetic fields with photon beams: Use of circular current loops

International Nuclear Information System (INIS)

Jette, David

2001-01-01

Strong transverse magnetic fields can produce very large dose enhancements and reductions in localized regions of a patient under irradiation by a photon beam. Through EGS4 Monte Carlo simulations, we have examined the effects of applying a magnetic field produced by a pair of circular current loops to a photon beam penetrating a water phantom of finite thickness. We have indeed found very substantial localized dose enhancements, albeit with no corresponding dose reduction just distal to the region of dose enhancement. (However, dose reduction does occur near the distal end of the phantom.) We have also observed two phenomena to be concerned with, for this configuration: significant broadening of the penumbra close to the current loop, and narrowness of the enhanced dose region in a plane parallel to the planes of the loops. We have also examined the use of a single current loop to produce the magnetic field, and have found great asymmetry in the dose distribution; this asymmetry appears to make it impossible to treat with a single circular magnet a tumor of large dimension extending below the application surface

Decoding spatial and temporal features of neuronal cAMP/PKA signaling with FRET biosensors.

Science.gov (United States)

Castro, Liliana R V; Guiot, Elvire; Polito, Marina; Paupardin-Tritsch, Daniéle; Vincent, Pierre

2014-02-01

Cyclic adenosine monophosphate (cAMP) and the cyclic-AMP-dependent protein kinase (PKA) regulate a plethora of cellular functions in virtually all eukaryotic cells. In neurons, the cAMP/PKA signaling cascade controls a number of biological properties such as axonal growth, pathfinding, efficacy of synaptic transmission, regulation of excitability, or long term changes. Genetically encoded optical biosensors for cAMP or PKA are considerably improving our understanding of these processes by providing a real-time measurement in living neurons. In this review, we describe the recent progress made in the creation of biosensors for cAMP or PKA activity. These biosensors revealed profound differences in the amplitude of the cAMP signal evoked by neuromodulators between various neuronal preparations. These responses can be resolved at the level of individual neurons, also revealing differences related to the neuronal type. At the sub-cellular level, biosensors reported different signal dynamics in domains like dendrites, cell body, nucleus, and axon. Combining this imaging approach with pharmacology or genetic models points at phosphodiesterases and phosphatases as critical regulatory proteins. Biosensor imaging will certainly emerge as a forefront tool to decipher the subtle mechanics of intracellular signaling. This will certainly help us to understand the mechanism of action of current drugs and foster the development of novel molecules for neuropsychiatric diseases. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Urban Agglomeration and Extension in Northern Coast of West Java: A Transformation into Mega Region

Science.gov (United States)

Octifanny, Y.; Hudalah, D.

2017-07-01

In the past decade, at least three neighbouring metropolitan areas in the northwestern part of the island have been merging with each other: Jakarta Metropolitan Area (Jabodetabek), Bandung Metropolitan Area (Bandung Raya), and Cirebon Metropolitan Area (Ciayumajakuning). It is expected to be the first island-based mega-conurbation. This paper explores the potential emergence of mega region as a ground study, where mega region can be used for economic, logistic, transportation development. Authors use scoring analysis from economic and demographic indicators. The outcomes found a new and larger formation of city-region in the northern coast road networks (Pantura) - specifically western part of Java Island.

Size Matters: The Contribution of Mega-Infauna to the Food ...

Science.gov (United States)

Large-bodied, invertebrates are common to infaunal communities of NE Pacific estuaries (e.g., bivalves, polychaetes, burrowing shrimps), but their contribution to the ecological structure, function and ecosystem services of most estuaries has been poorly characterized because they are difficult to sample and quantify. In a study of Yaquina estuary (Oregon) food webs, particular effort was made to quantify intertidal and subtidal mega-infauna using suction-excavated 40-cm diameter corers in addition to conventional sampling of macro-infauna. Additionally, the abundance and biomass of all floral and other faunal guilds (except microbial and mammalian guilds) were directly quantified or estimated from published studies, carbon and nitrogen stable isotopes were measured for abundant species, and inverse analysis was used to generate models of carbon flow within food webs of the lower and upper reaches of Yaquina estuary. Benthic invertebrates dominated the biomass and respiration among faunal guilds in both estuarine reaches, whereas biomass and respiration of birds and fish were two orders-of-magnitude smaller. Mega-infauna, particularly intertidal burrowing shrimps and bivalves, constituted most of the benthic invertebrate biomass, respiration and secondary production in both reaches, although only a small fraction of the total infaunal abundance. Mega-infauna were dominant consumers of phytoplankton, major contributors of carbon to sediment organic matter, a

Teacher Counter Stories to a Citizenship Education Mega Policy Narrative. Preparing for Citizenship in Chile

Science.gov (United States)

Cavieres-Fernández, Eduardo

2017-01-01

The present article focuses on the counter stories of two Chilean social studies high school teachers. Counter stories describe how teachers use their professional experience to confront those mega narratives composed of dominant educational policies that impinge upon their pedagogical practices. The mega narrative described in this study as a…

Development of sewage system for mega-city Karachi

International Nuclear Information System (INIS)

Talat, B.; Ahsan-Ullah

2005-01-01

The growth of mega-cities in recent times has brought to the fore a large number of issues with respect environmental conditions such as development of slum areas, poor localities, solid waste disposal, management of sewage system, lack of open spaces and health facilities. One of the major issues effecting environment proper disposal of sewage and development of sewage system including recycling of sewage water and its use. The heavy pressure of population calls for adequate provision of sewage disposal in the new areas and remodeling of systems in the old areas of the cities to ensure a pollution-free environment. Recycling of sewage and prevention of sewage discharge into natural water channels and the sea has to be undertaken on urgent bases. The paper seeks to outline the present status of sewage system of the city of Karachi, the problems involved and the proposals for management and development of the system compatible with the need and requirement of mega-city population. (author)

Statistical spatial properties of speckle patterns generated by multiple laser beams

International Nuclear Information System (INIS)

Le Cain, A.; Sajer, J. M.; Riazuelo, G.

2011-01-01

This paper investigates hot spot characteristics generated by the superposition of multiple laser beams. First, properties of speckle statistics are studied in the context of only one laser beam by computing the autocorrelation function. The case of multiple laser beams is then considered. In certain conditions, it is shown that speckles have an ellipsoidal shape. Analytical expressions of hot spot radii generated by multiple laser beams are derived and compared to numerical estimates made from the autocorrelation function. They are also compared to numerical simulations performed within the paraxial approximation. Excellent agreement is found for the speckle width as well as for the speckle length. Application to the speckle patterns generated in the Laser MegaJoule configuration in the zone where all the beams overlap is presented. Influence of polarization on the size of the speckles as well as on their abundance is studied.

Finding ultracool brown dwarfs with MegaCam on CFHT: method and first results

Science.gov (United States)

Delorme, P.; Willott, C. J.; Forveille, T.; Delfosse, X.; Reylé, C.; Bertin, E.; Albert, L.; Artigau, E.; Robin, A. C.; Allard, F.; Doyon, R.; Hill, G. J.

2008-06-01

Aims: We present the first results of a wide field survey for cool brown dwarfs with the MegaCam camera on the CFHT telescope, the Canada-France Brown Dwarf Survey, hereafter CFBDS. Our objectives are to find ultracool brown dwarfs and to constrain the field-brown dwarf mass function thanks to a larger sample of L and T dwarfs. Methods: We identify candidates in CFHT/MegaCam i' and z' images using optimised psf-fitting within Source Extractor, and follow them up with pointed near-infrared imaging on several telescopes. Results: We have so far analysed over 350 square degrees and found 770 brown dwarf candidates brighter than z'_AB=22.5. We currently have J-band photometry for 220 of these candidates, which confirms 37% as potential L or T dwarfs. Some are among the reddest and farthest brown dwarfs currently known, including an independent identification of the recently published ULAS J003402.77-005206.7 and the discovery of a second brown dwarf later than T8, CFBDS J005910.83-011401.3. Infrared spectra of three T dwarf candidates confirm their nature, and validate the selection process. Conclusions: The completed survey will discover ~100 T dwarfs and ~500 L dwarfs or M dwarfs later than M8, approximately doubling the number of currently known brown dwarfs. The resulting sample will have a very well-defined selection function, and will therefore produce a very clean luminosity function. Based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at TERAPIX and the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS. Based on observations made

MEGA5: Molecular Evolutionary Genetics Analysis Using Maximum Likelihood, Evolutionary Distance, and Maximum Parsimony Methods

Science.gov (United States)

Tamura, Koichiro; Peterson, Daniel; Peterson, Nicholas; Stecher, Glen; Nei, Masatoshi; Kumar, Sudhir

2011-01-01

Comparative analysis of molecular sequence data is essential for reconstructing the evolutionary histories of species and inferring the nature and extent of selective forces shaping the evolution of genes and species. Here, we announce the release of Molecular Evolutionary Genetics Analysis version 5 (MEGA5), which is a user-friendly software for mining online databases, building sequence alignments and phylogenetic trees, and using methods of evolutionary bioinformatics in basic biology, biomedicine, and evolution. The newest addition in MEGA5 is a collection of maximum likelihood (ML) analyses for inferring evolutionary trees, selecting best-fit substitution models (nucleotide or amino acid), inferring ancestral states and sequences (along with probabilities), and estimating evolutionary rates site-by-site. In computer simulation analyses, ML tree inference algorithms in MEGA5 compared favorably with other software packages in terms of computational efficiency and the accuracy of the estimates of phylogenetic trees, substitution parameters, and rate variation among sites. The MEGA user interface has now been enhanced to be activity driven to make it easier for the use of both beginners and experienced scientists. This version of MEGA is intended for the Windows platform, and it has been configured for effective use on Mac OS X and Linux desktops. It is available free of charge from http://www.megasoftware.net. PMID:21546353

LAMPF experimental-area beam current monitors

International Nuclear Information System (INIS)

Tallerico, P.J.

1975-01-01

This paper summarizes the design and operational performance of a wide- range current monitor system used to measure charged-particle currents in the experimental areas of the Clinton P. Anderson Meson Physics Facility (LAMPF), a proton accelerator. The major features of the system are high sensitivity, wide dynamic range, and the ability to withstand high levels of radiation. The current pulses detected are from 50 μs to 1 ms in duration at repetition rates of from 1 to 120 Hz. The pulse amplitude varies from 1 μA to 17 mA of protons or H - ions. Both real-time and integrated outputs are available, and the minimum detectable currents are 1 μA at the video output and 50 nA at the integrated output. The basic system is comprised of toroids, preamplifiers, signal conditioners, voltage-to-frequency converters, and digital accumulators. The entire system is spread out over 1 km of beam pipe. Provision is made for calibration and for sending the outputs to remote users. The system is normally controlled by a small digital computer, which allows the system to be quite flexible in operation. The design features of the toroids and the associated electronics are discussed in detail, with emphasis on the steps taken to reduce noise and make the toroids temperature and radiation resistant

Characterization techniques for the high-brightness particle beams of the Advanced Photon Source (APS)

International Nuclear Information System (INIS)

Lumpkin, A.H.

1993-01-01

The Advanced Photon Source (APS) will be a third-generation synchrotron radiation (SR) user facility in the hard x-ray regime (10--100 keV). The design objectives for the 7-GeV storage ring include a positron beam natural emittance of 8 x 10 -9 m-rad at an average current of 100 mA. Proposed methods for measuring the transverse and longitudinal profiles will be described. Additionally, a research and development effort using an rf gun as a low-emittance source of electrons for injection into the 200- to 650-MeV linac subsystem is underway. This latter system is projected to produce electron beams with a normalized, rms emittance of ∼2 π mm-mrad at peak currents of near one hundred amps. This interesting characterization problem will also be briefly discussed. The combination of both source types within one laboratory facility will stimulate the development of diagnostic techniques in these parameter spaces

Interaction of high-current relativistic electron beams with plasma. Physical nature of the phenomenon and its application in microwave electronics

International Nuclear Information System (INIS)

Rukhadze, A.A.

1981-01-01

Pulsed high-current electron beams with characteristic parameters: electron energy 10 5 -10 7 eV, electron current 10 3 -10 6 A, pulse duration 10 -8 -10 -6 s, beam energy 10 2 -10 6 J and power 10 8 -10 13 W, are widely used in different branches of science and technology such as controlled thermonuclear fusion, relativistic microwave electronics, powerful semiconductors, chemical and gaseous lasers, new principles of heavy-ion acceleration, and long-distance energy transmission. The paper discusses a new branch of science - pulsed high-current electronics, which has its own experimental technique and methods of theoretical analysis. Parts I and II determine what is meant by ''high current'' in an electron beam and calculate the maximum obtainable current values; these calculations are made for the simplest geometrical configurations realizable in practice. Current methods for theoretical analysis of high-current electron beam physics are described, together with classification of current experimental devices for generating such beams according to high-current parameters. The stability of electron beams is discussed and the concept of critical currents is introduced. Part III gives a detailed account of plasma-beam instability which occurs on the interaction of a high-current electron beam with high-density space-limited plasma. The linear and non-linear stages of beam instability are considered. The given theory is used for calculations for amplifiers and microwave generators of electromagnetic radiation. Finally, the experimental achievements in high-current relativistic microwave electronics are reviewed. (author)

Superconducting quantum interference monitor of charged particle beam current

International Nuclear Information System (INIS)

Gertsev, K.F.; Mikheev, M.S.

1981-01-01

Description and test results of the monitor of charged particle beam current on the base of the high-frequency superconducting quantum interference detector with lead slotted shield are presented. The toroidal superconducting coil, which covers the measured beam has 16 turns wound by the lead belt of 7 mm width with 0.5 mm gaps between the turns. A superconducting low-coupling monitor having two holes and point oxidated niobium contact has been used in the mode of quanta counting of magnetic flux. The lead point shield was 2 mm thick and it had 30 mm aperture. The coefficient of background shielding within 0-200 Hz frequency range constituted more than 10 8 . The threshold current resolution of the monitor had the value less than 01 μA √Hz. The suggested monitor requires helium cooling. The proposed design of the monitor is applicable for mounting on the vacuum chamber when it is surrounded by helium conductor. In other cases mounting of low-powerful autonomic system or cryostat of helium storage up to several weeks is possible [ru

Non-intercepting beam intensity measurements towards pico-ampere. Cryogenic current comparators for FAIR

Energy Technology Data Exchange (ETDEWEB)

Kurian, Febin [GSI Helmholtzzentrum fuer Schwerionenforschung (Germany); Goethe University, Frankfurt am Main (Germany); Helmholtz Institute Jena (Germany); Schwickert, Marcus; Sieber, Thomas; Kowina, Piotr; Reeg, Hansjoerg [GSI Helmholtzzentrum fuer Schwerionenforschung (Germany); Geithner, Rene; Neubert, Ralf; Seidel, Paul; Golm, Jessica [Friedrich-Schiller-Universitaet Jena (Germany); Stoehlker, Thomas [GSI Helmholtzzentrum fuer Schwerionenforschung (Germany); Helmholtz Institute Jena (Germany); Friedrich-Schiller-Universitaet Jena (Germany)

2016-07-01

To satisfy the requirement of non-interceptive measurement of beam intensity down to nA range foreseen in the upcoming FAIR accelerator facility, several Cryogenic Current Comparator (CCC) systems are planned to be installed in its beam transfer lines and storage rings. As a test bench for the development of advanced CCC systems for these installations, the existing CCC system at GSI has been recommissioned and upgraded with advanced sensor components. Successful beam intensity measurements using this upgraded CCC system will be reported in this contribution. Apart from the beam measurements, several operational aspects of the CCC system were investigated, such as the baseline drifts and various noise influences. Combining the operational experiences and boundary conditions given at various installation locations in the FAIR facility, an advanced CCC system is currently under development and is planned to be installed at the Cryring facility at GSI for test measurements. Details on the development of this advanced CCC system will also be presented in this contribution.

Research of transportation efficiency of low-energy high- current electron beam in plasma channel in external magnetic field

International Nuclear Information System (INIS)

Vagin, E S; Grigoriev, V P

2015-01-01

Effective high current (5-20 kA) and low energy (tens of keV) electrons beam transportation is possible only with almost complete charging neutralization. It is also necessary to use quite high current neutralization for elimination beam self-pinching effect. The research is based on the self-consistent mathematical model that takes into account beam and plasma particles dynamic, current and charge neutralization of electron beam and examines the transportation of electron beam into a chamber with low-pressure plasma in magnetic field. A numerical study was conducted using particle in cell (PIC) method. The study was performed with various system parameters: rise time and magnitude of the beam current, gas pressure and plasma density and geometry of the system. Regularities of local virtual cathode field generated by the beam in the plasma channel, as well as ranges of parameters that let transportation beam with minimal losses, depending on the external magnetic field were determined through a series of numerical studies. In addition, the assessment of the impact of the plasma ion mobility during the transition period and during steady beam was performed. (paper)

Tsunami simulations of mega-thrust earthquakes in the Nankai–Tonankai Trough (Japan) based on stochastic rupture scenarios

KAUST Repository

Goda, Katsuichiro

2017-02-23

In this study, earthquake rupture models for future mega-thrust earthquakes in the Nankai–Tonankai subduction zone are developed by incorporating the main characteristics of inverted source models of the 2011 Tohoku earthquake. These scenario ruptures also account for key features of the national tsunami source model for the Nankai–Tonankai earthquake by the Central Disaster Management Council of the Japanese Government. The source models capture a wide range of realistic slip distributions and kinematic rupture processes, reflecting the current best understanding of what may happen due to a future mega-earthquake in the Nankai–Tonankai Trough, and therefore are useful for conducting probabilistic tsunami hazard and risk analysis. A large suite of scenario rupture models is then used to investigate the variability of tsunami effects in coastal areas, such as offshore tsunami wave heights and onshore inundation depths, due to realistic variations in source characteristics. Such investigations are particularly valuable for tsunami hazard mapping and evacuation planning in municipalities along the Nankai–Tonankai coast.

Development of high-current pulsed heavy-ion-beam technology for applications to materials processing

Energy Technology Data Exchange (ETDEWEB)

Ito, Hiroaki; Ochiai, Yasushi; Masugata, Katsumi [University of Toyama, Toyama (Japan)

2011-12-15

Development of intense pulsed heavy ion beam technology for applications to materials processing is described. We have developed a magnetically insulated ion diode for the generation of intense pulsed metallic ion beams in which a vacuum arc plasma gun is used as the ion source. When the ion diode was successfully operated at a diode voltage of 220 kV and a diode current of 10 kA, an ion beam with an ion current density of >200 A/cm{sup 2} and a pulse duration of 40 ns was obtained. The ion composition was evaluated by using a Thomson parabola spectrometer, and the ion beam consisted of aluminum ions (Al{sup (1-3)+}) with an energy of 140 - 740 keV and protons with an energy of 160 - 190 keV; the purity was estimated to be 89%, which was much higher than that of the pulsed ion beam produced in a conventional ion diode. The development of a bipolar pulse accelerator (BPA) was reported in order to improve the purity of intense pulsed ion beams. A double coaxial type bipolar pulse generator was developed as the power supply of the BPA. When a bipolar pulse with a voltage of {+-}90 kV and a pulse duration of about 65 ns was applied to the drift tube of the BPA, the ion beam with an ion current density of 2 A/cm{sup 2} and a pulse duration of 30 ns was observed 25 mm downstream from the cathode surface, which suggested bipolar pulse acceleration.

The Interplay between Cyclic AMP, MAPK, and NF-κB Pathways in Response to Proinflammatory Signals in Microglia

Directory of Open Access Journals (Sweden)

Mousumi Ghosh

2015-01-01

Full Text Available Cyclic AMP is an important intracellular regulator of microglial cell homeostasis and its negative perturbation through proinflammatory signaling results in microglial cell activation. Though cytokines, TNF-α and IL-1β, decrease intracellular cyclic AMP, the mechanism by which this occurs is poorly understood. The current study examined which signaling pathways are responsible for decreasing cyclic AMP in microglia following TNF-α stimulation and sought to identify the role cyclic AMP plays in regulating these pathways. In EOC2 microglia, TNF-α produced a dramatic reduction in cyclic AMP and increased cyclic AMP-dependent PDE activity that could be antagonized by Rolipram, myristoylated-PKI, PD98059, or JSH-23, implicating a role for PDE4, PKA, MEK, and NF-κB in this regulation. Following TNF-α there were significant increases in iNOS and COX-2 immunoreactivity, phosphorylated ERK1/2 and NF-κB-p65, IκB degradation, and NF-κB p65 nuclear translocation, which were reduced in the presence of high levels of cyclic AMP, indicating that reductions in cyclic AMP during cytokine stimulation are important for removing its inhibitory action on NF-κB activation and subsequent proinflammatory gene expression. Further elucidation of the signaling crosstalk involved in decreasing cyclic AMP in response to inflammatory signals may provide novel therapeutic targets for modulating microglial cell activation during neurological injury and disease.

7 CFR 772.14 - Reamortization of AMP loans.

Science.gov (United States)

2010-01-01

... 7 Agriculture 7 2010-01-01 2010-01-01 false Reamortization of AMP loans. 772.14 Section 772.14... AGRICULTURE SPECIAL PROGRAMS SERVICING MINOR PROGRAM LOANS § 772.14 Reamortization of AMP loans. The Agency may approve reamortization of AMP loans provided: (a) There is no extension of the final maturity date...

Decommissioning of the High Flux Beam Reactor at Brookhaven Lab

Energy Technology Data Exchange (ETDEWEB)

Hu, J. P. [Brookhaven National Lab. (BNL), Upton, NY (United States); Reciniello, R. N. [Brookhaven National Lab. (BNL), Upton, NY (United States); Holden, N. E. [Brookhaven National Lab. (BNL), Upton, NY (United States)

2011-05-27

The High Flux Beam Reactor at the Brookhaven National Laboratory was a heavy water cooled and moderated reactor that achieved criticality on October 31, 1965. It operated at a power level of 40 mega-watts. An equipment upgrade in 1982 allowed operations at 60 mega-watts. After a 1989 reactor shutdown to reanalyze safety impact of a hypothetical loss of coolant accident, the reactor was restarted in 1991 at 30 mega-watts. The HFBR was shutdown in December 1996 for routine maintenance and refueling. At that time, a leak of tritiated water was identified by routine sampling of ground water from wells located adjacent to the reactor’s spent fuel pool. The reactor remained shutdown for almost three years for safety and environmental reviews. In November 1999 the United States Department of Energy decided to permanently shutdown the HFBR. The decontamination and decommissioning of the HFBR complex, consisting of multiple structures and systems to operate and maintain the reactor, were complete in 2009 after removing and shipping off all the control rod blades. The emptied and cleaned HFBR dome which still contains the irradiated reactor vessel is presently under 24/7 surveillance for safety. Details of the HFBR cleanup conducted during 1999-2009 will be described in the paper.

[A high sensitivity search for mu gamma: The mega experiment at LAMPF

International Nuclear Information System (INIS)

1990-01-01

During the past 12 month period the Valparaiso University group has been active on LAMPF experiment 969, known as the MEGA experiment. This experiment is a search for the decay μ -> e γ, a decay which would violate lepton number conservation and which is strictly forbidden by the standard model for electroweak interactions. Previous searches for this decay mode have set limit the present day limit of 4.9 x 10 -11 . The MEGA experiment is designed to test the standard model predictions to one part in 10 +13

An update on MEGA: An experimental search for lepton number non-conservation

International Nuclear Information System (INIS)

Hungerford, E.V.

1998-01-01

Mega is an experiment to search for the decay μ→eγ. It is designed to test lepton-number conservation in muon decay by a background free measurement in this branching ratio at a sensitivity of a few x10 -13 . This paper reports particularly on the design and performance of the MEGA detector, as the lessons learned previously are important when new experiments are proposed which would increase the sensitivity of such a measurement down to a branching ratio on the order of 10 -14 . copyright 1998 American Institute of Physics

"cAMP sponge": a buffer for cyclic adenosine 3', 5'-monophosphate.

Directory of Open Access Journals (Sweden)

Konstantinos Lefkimmiatis

Full Text Available BACKGROUND: While intracellular buffers are widely used to study calcium signaling, no such tool exists for the other major second messenger, cyclic AMP (cAMP. METHODS/PRINCIPAL FINDINGS: Here we describe a genetically encoded buffer for cAMP based on the high-affinity cAMP-binding carboxy-terminus of the regulatory subunit RIbeta of protein kinase A (PKA. Addition of targeting sequences permitted localization of this fragment to the extra-nuclear compartment, while tagging with mCherry allowed quantification of its expression at the single cell level. This construct (named "cAMP sponge" was shown to selectively bind cAMP in vitro. Its expression significantly suppressed agonist-induced cAMP signals and the downstream activation of PKA within the cytosol as measured by FRET-based sensors in single living cells. Point mutations in the cAMP-binding domains of the construct rendered the chimera unable to bind cAMP in vitro or in situ. Cyclic AMP sponge was fruitfully applied to examine feedback regulation of gap junction-mediated transfer of cAMP in epithelial cell couplets. CONCLUSIONS: This newest member of the cAMP toolbox has the potential to reveal unique biological functions of cAMP, including insight into the functional significance of compartmentalized signaling events.

S-AMP: Approximate Message Passing for General Matrix Ensembles

DEFF Research Database (Denmark)

Cakmak, Burak; Winther, Ole; Fleury, Bernard H.

2014-01-01

the approximate message-passing (AMP) algorithm to general matrix ensembles with a well-defined large system size limit. The generalization is based on the S-transform (in free probability) of the spectrum of the measurement matrix. Furthermore, we show that the optimality of S-AMP follows directly from its......We propose a novel iterative estimation algorithm for linear observation models called S-AMP. The fixed points of S-AMP are the stationary points of the exact Gibbs free energy under a set of (first- and second-) moment consistency constraints in the large system limit. S-AMP extends...

Current drive by neutral beams, rotating magnetic fields and helicity injection in compact toroids

International Nuclear Information System (INIS)

Farengo, R.

2002-01-01

A Monte-Carlo code is used to study neutral beam current drive in Spheromaks. The exact particle trajectories are followed in the self-consistent equilibria calculated including the beam current. Reducing Z(eff) does not increase the current drive efficiency because the reduction of the stopping cross section is compensated by an increase in the electron canceling current. Significant changes in the safety factor profile can be produced with relatively low beam currents. Minimum dissipation states of a flux core spheromak sustained by helicity injection are presented. Helicity balance is used as a constraint and the resistivity is considered to be non-uniform. Two types of relaxed states are found; one has a central core of open flux surrounded by a toroidal region of closed flux surfaces and the other has the open flux wrapped around the closed flux surfaces. Non-uniform resistivity effects can be very important due to the changes they produce in the safety factor profile. A hybrid, fluid electrons particle ions, code is employed to study ion dynamics in FRCs sustained by rotating magnetic fields. (author)

Prospects for utilization of Electron Beam Accelerators (EBAs) for processing of food products

International Nuclear Information System (INIS)

Sarma, K.S.

2014-01-01

Radiation processing using gamma radiation and high energy electron beams has been in practice for more than three decades in the industry. Since gamma radiation has the ability of higher penetration in the material, large scale irradiators (mainly based on mega curies of 60 Co radioactive source) are successfully employed for treating bulk products in sterilization and food preservation applications. Electron beam, due to its low penetration, has been exploited exclusively for applications involving polymer modifications to irradiate thin finished end products like electrical cable insulations, heat shrinkable sheets, tubes, automobile tyres etc using high power EBAs (energies 0.5 MeV-4 MeV and powers around ∼100 kW). Out of around 2500 industrial EB units currently employed worldwide (with total installed power above 150 MWL 90% are in the low to medium energy range (0.5 MeV to 4 MeV) being used for polymer modifications. However, recent technological advances in the manufacturing sector of industrial high energy EBAs and product handling systems resulted in widening utilization of EB technology for applications involving bulk product irradiation

New data acquisition system for beam loss monitor used in J-PARC main ring

Science.gov (United States)

Satou, K.; Toyama, T.; Kamikubota, N.; Yoshida, S.; Matsushita, J.; Wakita, T.; Sugiyama, M.; Morino, T.

2018-04-01

A new data acquisition system has been developed continually as a part of the development of a new beam loss monitor (BLM) system for the J-PARC main ring. This development includes a newly designed front-end isolation amp that uses photo-couplers and a VME-based new analog-to-digital converter (ADC) system. Compared to the old amp, the new amp has a 10 times higher conversion impedance for the input current to the output voltage; this value is 1 M Ω. Moreover, the bandwidth was improved to from DC to 50 kHz, which is about two orders of magnitude greater than the previously used bandwidth. The theoretical estimations made in this study roughly agree with the frequency response obtained for the new system. The new ADC system uses an on-board field-programmable gate array chip for signal processing. By replacing the firmware of this chip, changes pertaining to future accelerator upgrade plans may be introduced into the new ADC system; in addition, the ADC system can be used in other applications. The sampling speed of the system is 1 MS/s, and it exhibits a 95 dBc spurious-free dynamic range and 16.5 effective number of bits. The obtained waveform and integrated charge data are compared with two reference levels in the ADC system. If the data exceeds the reference level, the system generates an alarm to dump the beams. By using the new data acquisition system, it was proved that the new BLM system shows a wide dynamic range of 160 dB. In this study, the details of the new data acquisition system are described.

Development of large area resistive electrodes for ATLAS NSW MicroMEGAS

CERN Document Server

Ochi, Atsuhiko; The ATLAS collaboration

2015-01-01

MicroMegas with resistive anode will be used for the NSW upgrade of the ATLAS experiment at LHC. The resistive electrode is one of key technology for MPGDs to prevent sparks. Large area resistive electrodes for the MM have been developed using two different technology; screen printing and carbon sputtering. Maximum size of each resistive foil is 45cm x 220cm with printed pattern of 425 micron pitch strips. Those technologies are also suitable to mass production. The prototypes of series production model have been produced successfully. We will report the development and production status and test results of the resistive MicroMegas.

Construction and performance of MEGAs low-mass, high-rate cylindrical MWPCs

Science.gov (United States)

Cooper, M. D.; Armijo, V.; Black, J. K.; Bolton, R. D.; Carius, S.; Espinoza, C.; Hart, G.; Hogan, G. E.; Gonzales, A.; Kroupa, M. A.; Mischke, R. E.; Sandoval, J.; Schilling, S.; Sena, J.; Suazo, G.; Whitehouse, D. A.; Wilkinson, C. A.; Stantz, K.; Szymanski, J. J.; Jui, C. C.; Gagliardi, C. A.; Tribble, R. E.; Tu, X.-L.; Fisk, R. J.; Koetke, D. D.; Manweiler, R. W.; Nord, P. M.; Stanislaus, S.; Piilonen, L. E.; Zhang, Y. D.

A design for extremely low mass, high-resolution multiwire proportional chambers (MWPC) was achieved by the MEGA collaboration in its experiment to search for the lepton family number violating decay μ→eγ. To extend the present branching ratio limit by over an order of magnitude, these MWPCs were operated in high particle fluxes. They showed minimal effects of aging, and evidenced spatial and energy resolutions for the orbiting positrons from muon decay which were consistent with our design parameters. The unique features of these chambers, their assembly into the MEGA positron spectrometer, and their performance during the experiment are described in this paper.

AMPS Supporting Research and Technology (SR and T) report. Atmospheric, Magnetospheric and Plasmas in Space (AMPS) definition study

Science.gov (United States)

1976-01-01

A listing of candidate technology areas that require additional study is presented. These candidate tasks, identified during the AMPS Phase B studies, are requisites to the design, development, and operation of the AMPS concept selected for preliminary design.

Current pulse shaping of the load current on PTS

Directory of Open Access Journals (Sweden)

Minghe Xia

2016-02-01

Full Text Available The typical rise time of PTS machine is ∼110 ns with about 10 MA peak current under short pulse mode when all 24 modules discharge simultaneously. By distributing the trigger times of 12 laser beams logically and adjusting the statues of the pulse output switches, longer rise-time pulse can be obtained on the PTS facility. Based on the required pulse shape, whole circuit simulations will be used to calculate the trigger times of each laser triggering gas switch and the status of the pulse output switches. The rise time of the current is determined by the time difference between the first and last trigged laser triggering gas switches. In order to trigger the laser triggering gas switch, sufficient laser power is needed to be sent into the gap of the gas switches. The gas pressure and voltage difference on the two electrodes of the gas switches also affect the triggering of the gas switches, and the voltage added on the gas switch is determined by its transition time. Traditionally the trigger time difference should be less than the transition time of the two neighboring modules. A new simulation model of PTS shows one can break this transition time limits. Series of current pulse shaping experiments have been investigated on the PTS (Primary Test Stand. As results, more than 5 MA peak current were successfully achieved on the load with a rise time of 600 ns. This study and experiments of the pulse shaping on PTS demonstrate the adaptable ability of the PTS for offering different waveform of mega ampere current pulse for different research purpose.

Current status of electron beam treatment of flue gas in China

International Nuclear Information System (INIS)

Wang Zhiguang

2006-01-01

Fossil resource especially coal will remain the main energy resource in China over the next 3 ∼4 decades. Pollution of flue gas from fossil power station is one problem being desiderated to solve since 1990's. Electron beam treatment of flue gas as an advanced technique has been developed and used by some institutes and industries in China. The current status of flue gas treatment using electron beam and the development of electron accelerator in China are reviewed. (author)

Design of multi-megawatt actively cooled beam dumps for the Neutral-Beam Engineering Test Facility

International Nuclear Information System (INIS)

Paterson, J.A.; Koehler, G.; Wells, R.P.

1981-10-01

The Neutral Beam Engineering Test Facility will test Neutral Beam Sources up to 170 keV, 65 Amps, with 30 second beam-on times. For this application actively cooled beam dumps for both the neutral and ionized particles will be required. The dumps will be able to dissipate a wide range of power density profiles by utilizing a standard modular panel design which is incorporated into a moveable support structure. The thermal hydraulic design of the panels permit the dissipation of 2 kW/cm 2 anywhere on the panel surface. The water requirements of the dumps are optimized by restricting the flow to panel sections where the heat flux falls short of the design value. The mechanical design of the beam-dump structures is described along with tests performed on a prototype panel. The prototype tests were performed on two different panel designs, one manufactured by Mc Donnell Douglas (MDAC) the other by United Technologies (UT). The dissipation capabilities of the panels were tested at the critical regions to verify their use in the beam dump assemblies

Production of tightly focused E-beam with high-current accelerators

International Nuclear Information System (INIS)

Poukey, J.W.; Mazarakis, M.G.; Frost, C.A.; Ramirez, J.J.

1991-01-01

Using numerical modeling the authors study several approaches to the problem of designing an injector to produce a 3-30 kA, 2-4 mm diameter electron beam in the energy range 10-20 MeV. The cathode may be small in diameter and immersed in a strong magnetic field, producing an equilibrium beam for transport to a target (the immersed case). This approach appears to be the most promising for applications such as radiography, and the authors shall emphasize it in this paper. The alternative is the conventional non-immersed cathode, in which the beam from a larger-radius, cold-beam cathode is focused with magnetic lenses to a small spot on the target. Because the non-immersed cathode, in which the beam from a larger-radius, cold-beam cathode is focused with a magnetic lenses to a small spot on the target. Because the non-immersed case has been extensively studied, and because it has advantages for these purposes, the authors shall only discuss a few of the non-immersed-cathode injector studies, primarily for purposes of comparison. Either type of diode is to be powered by an inductive voltage adder based on the successful SABRE/Hermes III/RADLAC (SMILE) magnetically-insulated-transmission-line design concepts. A possible variation uses a re-entrant geometry with low electric stresses so that only the cathode face emits. The authors discuss issues such as dumping excess current and voltage dependence of the focus

Influence of total beam current on HRTEM image resolution in differentially pumped ETEM with nitrogen gas.

Science.gov (United States)

Bright, A N; Yoshida, K; Tanaka, N

2013-01-01

Environmental transmission electron microscopy (ETEM) enables the study of catalytic and other reaction processes as they occur with Angstrom-level resolution. The microscope used is a dedicated ETEM (Titan ETEM, FEI Company) with a differential pumping vacuum system and apertures, allowing aberration corrected high-resolution transmission electron microscopy (HRTEM) imaging to be performed with gas pressures up to 20 mbar in the sample area and with significant advantages over membrane-type E-cell holders. The effect on image resolution of varying the nitrogen gas pressure, electron beam current density and total beam current were measured using information limit (Young's fringes) on a standard cross grating sample and from silicon crystal lattice imaging. As expected, increasing gas pressure causes a decrease in HRTEM image resolution. However, the total electron beam current also causes big changes in the image resolution (lower beam current giving better resolution), whereas varying the beam current density has almost no effect on resolution, a result that has not been reported previously. This behavior is seen even with zero-loss filtered imaging, which we believe shows that the drop in resolution is caused by elastic scattering at gas ions created by the incident electron beam. Suitable conditions for acquiring high resolution images in a gas environment are discussed. Lattice images at nitrogen pressures up to 16 mbar are shown, with 0.12 nm information transfer at 4 mbar. Copyright © 2012 Elsevier B.V. All rights reserved.

Trends in vehicular emissions in China's mega cities from 1995 to 2005

International Nuclear Information System (INIS)

Wang Haikun; Fu Lixin; Zhou Yu; Du Xuan; Ge Weihua

2010-01-01

Multiyear inventories of vehicular emissions in Beijing, Shanghai and Guangzhou from 1995 through 2005 have been developed in this paper to study the vehicle emissions trends in China's mega cities during the past decade. The results show that the vehicular emissions of CO, HC, NO x and PM 10 have begun to slow their growth rates and perhaps even to decline in recent years due to the implementation of measures to control vehicular emissions in these cities. However, vehicular CO 2 emissions have substantially increased and still continue to grow due to little fuel economy improvement. Passenger cars and large vehicles (including heavy duty trucks and buses) are the major sources of vehicular CO 2 and CO emissions while large vehicles were responsible for nearly 70% and 80% of the vehicular NO x and PM 10 emissions in these mega cities. Motorcycles are also important contributors to vehicular emissions in Guangzhou and Shanghai. - The vehicular emissions (except CO 2 ) in China's mega cities have begun to slow their rates of growth and even to decline during the past decade.

Mega-minería y colonialidad. Nuevas estrategias de legitimación, viejos binomios

OpenAIRE

Julieta Godfrid

2016-01-01

The new international division of labor that takes place under neoliberal globalization relegates Latin American countries to mere commodity producers. In this scenario, in Argentina in recent years it has rapidly expanded the mega-opencast mining, producing a multiplicity of socio-environmental impacts and bringing the emergence of a lot of conflicts. Successive socio-environmental critics contributed to delegitimize the corporate image of the sector, discrediting the mega-mining activity. F...

A fast non-intercepting linac beam position and current monitor

International Nuclear Information System (INIS)

Hansen, J.W.; Wille, M.

1982-01-01

A non-intercepting beam monitor consisting of four detecting loops is used to determine the spatial postion and current of a pulsed beam from an electron linear accelerator. The monitor detects the magnetic field radiated by the substructure of the electron bunches created by the accelerating microwave. The detecting loops are interconnected two by two, by means of two coaxial hybrid junctions, the two sets positioned perpendicular to each other. By means of the two signals from the diametrically positioned detecting loops, a good spatial displacement and current monitoring sensitivity are achieved by subtracting one signal from the other and adding the two signals, respectively. For displacements below 2 mm from the center axis an average sensitivity of 0.5 mV/mm x mA is measured, whereas displacements more than 2 mm yields 1.3 mV/mm x mA. A sensitivity of 0.2 mV/mA in current monitoring is measured, and the rise time of the monitored pulse signal is better than 5 ns measured from 10 to 90% of the pulse height. Design strategy and performance of the monitor are described. (orig.)

Comparison of typical mega cities in China using emergy synthesis

Science.gov (United States)

Zhang, L. X.; Chen, B.; Yang, Z. F.; Chen, G. Q.; Jiang, M. M.; Liu, G. Y.

2009-06-01

An emergy-based comparison analysis is conducted for three typical mega cities in China, i.e., Beijing, Shanghai and Guangzhou, from 1990 to 2005 in four perspectives including emergy intensity, resource structure, environmental pressure and resource use efficiency. A new index of non-renewable emergy/money ratio is established to indicate the utilization efficiency of the non-renewable resources. The results show that for the three mega urban systems, Beijing, Shanghai and Guangzhou, the total emergy inputs were 3.76E+23, 3.54E+23, 2.52E+23 sej in 2005, of which 64.88%, 91.45% and 72.28% were imported from the outsides, respectively. As to the indicators of emergy intensity involving the total emergy use, emergy density and emergy use per cap, three cities exhibited similar overall increase trends with annual fluctuations from 1990 to 2005. Shanghai achieved the highest level of economic development and non-renewable resource use efficiency, and meanwhile, lower proportion of renewable resource use and higher environmental pressure compared to those of Beijing and Guangzhou. Guangzhou has long term sustainability considering an amount of local renewable resources used, per capita emergy used, energy consumption per unit GDP and the ratio of waste to renewable emergy. It can be concluded that different emergy-based evaluation results arise from different geographical locations, resources endowments, industrial structures and urban orientations of the concerned mega cities.

Beam instrumentation for the BNL Heavy Ion Transfer Line

International Nuclear Information System (INIS)

Witkover, R.L.; Buxton, W.; Castillo, V.; Feigenbaum, I.; Lazos, A.; Li, Z.G.; Smith, G.; Stoehr, R.

1987-01-01

The Heavy Ion Transfer Line (HITL) was constructed to transport beams from the BNL Tandem Van de Graaff (TVDG) to be injected into the AGS. Because the beam line is approximately 2000 feet long and the particle rigidity is so low, 20 beam monitor boxes were placed along the line. The intensity ranges from 1 to 100 nanoAmps for the dc trace beam used for line set-up, to over 100 μA for the pulsed beam to be injected into the AGS. Profiles are measured using multiwire arrays (HARPS) while Faraday cups and beam transformers monitor the intensity. The electronics stations are operated through 3 Instrumentation Controllers networked to Apollo workstations in the TVDG and AGS control rooms. Details of the detectors and electronics designs and performance will be given

Catastrophic processes in dielectrics in irradiation by high-current electron beams

Energy Technology Data Exchange (ETDEWEB)

Oleshko, V. [Tomsk Polytechnic University, 634050 Tomsk (Russian Federation); Lisitsyna, L., E-mail: lisitsyn@tpu.r [Tomsk State University of Architecture and Building, 634003 Tomsk (Russian Federation); Malys, D.; Damamme, G. [Commissariat a l' energie atomique, Paris 75015 (France); Lisitsyn, V. [Tomsk Polytechnic University, 634050 Tomsk (Russian Federation)

2010-10-01

The results of the research in explosive decomposition of heavy metal azides initiated by electric ('streamer') charges induced by high-current electron beam have been considered. A physical model for initiation of heavy metal azides explosive decomposition by electron beam has been suggested. The model suggests formation of strong electric field in the sample and its neutralization by ultrasound anode charges. The streamer front generates 'hot spots' which start the formation of explosive decomposition sites in a condensed reactive material.

High-stable secondary-emission monitor for accelerated electron beam current

International Nuclear Information System (INIS)

Prudnikov, I.A.; Saksaganskij, G.L.; Bazhanov, E.B.; Zabrodin, B.V.

1977-01-01

A secondary-emission monitor for a 10 to 30 MeV electron beam (beam current is 10 -4 to 10 -2 A) is described. The monitor comprises a measuring electrode unit, titanium discharge-type pump, getter made of porous titanium, all enclosed in a metal casing. The measuring unit comprises three electrodes made of 20 μm aluminium foil. The secondary emission coefficient (5.19%+-0.06% for the electron energy of 20 MeV) is maintained stable for a long time. The monitor detects pulses of up to some nanoseconds duration. It is reliable in operation, and is recommended for a wide practical application

Cardiac cAMP: production, hydrolysis, modulation and detection

Directory of Open Access Journals (Sweden)

Cédric eBOULARAN

2015-10-01

Full Text Available Cyclic adenosine 3’,5’-monophosphate (cAMP modulates a broad range of biological processes including the regulation of cardiac myocyte contractile function where it constitutes the main second messenger for β-adrenergic receptors’ signaling to fulfill positive chronotropic, inotropic and lusitropic effects. A growing number of studies pinpoint the role of spatial organization of the cAMP signaling as an essential mechanism to regulate cAMP outcomes in cardiac physiology. Here, we will briefly discuss the complexity of cAMP synthesis and degradation in the cardiac context, describe the way to detect it and review the main pharmacological arsenal to modulate its availability.

Development of the High Current Ion Source for Neutral Beam Injection

Energy Technology Data Exchange (ETDEWEB)

Lee, Hun Ju; Kim, S. H.; Jang, D. H. [Jae Ju University, Jaeju (Korea, Republic of)

1997-08-01

The scope of the 1st year research is to design an 140keV deuterium ion source which has a beam current of 30-40A. According to the collected data, the model of an ion source for NBI of KSTAR was established. The negative ion source, which has good neutralization effecting in high energy, was selected. To generate a plasma, the thoriated tungsten filament was adopted. To increase the efficiency of plasma, the multi cusp type magnetic field was attached. The magnetic field was calculated by POISSON code. The extraction structure was designed with EGUN code, to extract the high quality ion beam. The design of a high current ion source for NBI was carried out. To develop the high current ion source with the high operational stability and the long lifetime, the parameters including an arc current, gas pressure and extraction voltage should be optimized. If designed ion source would be fabricated, its parameters could be optimized experimentally. Through the optimization of the ion source parameter, the core technology for NBI is established and the experiment of current drive in the fusion device can be performed. This technology also can be applied to the synthesis of new material and semiconductor industry. 18 refs., 11 tabs., 19 figs. (author)

First beam splashes at the LHC

CERN Multimedia

CERN Bulletin

2015-01-01

After a two-year shutdown, the first beams of Run 2 circulated in the LHC last Sunday. On Tuesday, the LHC operators performed dedicated runs to allow some of the experiments to record their first signals coming from particles splashed out when the circulating beams hit the collimators. Powerful reconstruction software then transforms the electronic signals into colourful images.     “Splash” events are used by the experiments to test their numerous subdetectors and to synchronise them with the LHC clock. These events are recorded when the path of particles travelling in the LHC vacuum pipe is intentionally obstructed using collimators – one-metre-long graphite or tungsten jaws that are also used to catch particles that wander too far from the beam centre and to protect the accelerator against unavoidable regular and irregular beam losses. The particles sprayed out of the collision between the beam and the collimators are mostly muons. ATLAS and CMS&amp...

Assessment of a Mega-Float on water quality and ecosystem in Tokyo bay; Choogata futaishiki kaiyo kozobutsu ga Tokyowan no suishitsu to seitaikei ni oyobosu eikyo ni tsuite

Energy Technology Data Exchange (ETDEWEB)

Kyozuka, Y.; Hu, C.; Hasemi, H. [Kyushu University, Fukuoka (Japan). Faculty of Engineering; Hikai, A.

1997-08-01

The effect on the marine environment in the bay when a Mega-Float is installed in a bay was investigated. The physical process such as a residual flow (including tidal currents, water temperature, salt, density, and density currents), and the ecosystem model for which floating organic matter and plankton are handled were incorporated to develop a program for water quality calculation in a bay. The program was used for Tokyo Bay and compared with the conventional calculation result and the oceanograhpic observation result. Simultaneously, the effect on the Mega-Float was considered. On the flow in Tokyo Bay in summer, the calculation result that comparatively coincided with the observation value in a residual flow level was obtained. The horizontal distribution of COD comparatively coincides with the existing observation result. The influence that the Mega-Float exerts on the flow, water temperature, water quality, and ecosystem in the ambient sea area was little and local in the calculation scale (L {times} B {times} d = 6 km {times} 3 km {times} 2 m) of this time. However, the difference occurring due to the design position must also be investigated in future. 12 refs., 8 figs., 5 tabs.

Implantation of Martian Materials in the Inner Solar System by a Mega Impact on Mars

Science.gov (United States)

Hyodo, Ryuki; Genda, Hidenori

2018-04-01

Observations and meteorites indicate that the Martian materials are enigmatically distributed within the inner solar system. A mega impact on Mars creating a Martian hemispheric dichotomy and the Martian moons can potentially eject Martian materials. A recent work has shown that the mega-impact-induced debris is potentially captured as the Martian Trojans and implanted in the asteroid belt. However, the amount, distribution, and composition of the debris has not been studied. Here, using hydrodynamic simulations, we report that a large amount of debris (∼1% of Mars’ mass), including Martian crust/mantle and the impactor’s materials (∼20:80), are ejected by a dichotomy-forming impact, and distributed between ∼0.5–3.0 au. Our result indicates that unmelted Martian mantle debris (∼0.02% of Mars’ mass) can be the source of Martian Trojans, olivine-rich asteroids in the Hungarian region and the main asteroid belt, and some even hit the early Earth. The evidence of a mega impact on Mars would be recorded as a spike of 40Ar–39Ar ages in meteorites. A mega impact can naturally implant Martian mantle materials within the inner solar system.

Analytically derived weighting factors for transmission tomography cone beam projections

International Nuclear Information System (INIS)

Yao Weiguang; Leszczynski, Konrad

2009-01-01

Weighting factors, which define the contributions of individual voxels of a 3D object to individual projection elements (pixels) on the detector, are the basic elements required in iterative tomographic reconstructions from transmission projections. Exact or as accurate as possible values for weighting factors are required in high-resolution reconstructions. Geometric complexity of the problem, however, makes it difficult to obtain exact weighting factor values. In this work, we derive an analytical expression for the weighting factors in cone beam projection geometry. The resulting formula is validated and applied to reconstruction from mega and kilovoltage x-ray cone beam projections. The reconstruction speed and accuracy are significantly improved by using the weighting factor values.

Electron and ion heat transport with lower hybrid current drive and neutral beam injection heating in ASDEX

International Nuclear Information System (INIS)

Soeldner, F.X.; Pereverzev, G.V.; Bartiromo, R.; Fahrbach, H.U.; Leuterer, F.; Murmann, H.D.; Staebler, A.; Steuer, K.H.

1993-01-01

Transport code calculations were made for experiments with the combined operation of lower hybrid current drive and heating and of neutral beam injection heating on ASDEX. Peaking or flattening of the electron temperature profile are mainly explained by modifications of the MHD induced electron heat transport. They originate from current profile changes due to lower hybrid and neutral beam current drive and to contributions from the bootstrap current. Ion heat transport cannot be described by one single model for all heating scenarios. The ion heat conductivity is reduced during lower hybrid heated phases with respect to Ohmic and neutral beam heating. (author). 13 refs, 5 figs

Fast wave current drive in neutral beam heated plasmas on DIII-D

International Nuclear Information System (INIS)

Petty, C.C.; Forest, C.B.; Pinsker, R.I.

1997-04-01

The physics of non-inductive current drive and current profile control using the fast magnetosonic wave has been demonstrated on the DIII-D tokamak. In non-sawtoothing discharges formed by neutral beam injection (NBI), the radial profile of the fast wave current drive (FWCD) was determined by the response of the loop voltage profile to co, counter, and symmetric antenna phasings, and was found to be in good agreement with theoretical models. The application of counter FWCD increased the magnetic shear reversal of the plasma and delayed the onset of sawteeth, compared to co FWCD. The partial absorption of fast waves by energetic beam ions at high harmonics of the ion cyclotron frequency was also evident from a build up of fast particle pressure near the magnetic axis and a correlated increase in the neutron rate. The anomalous fast particle pressure and neutron rate increased with increasing NBI power and peaked when a harmonic of the deuterium cyclotron frequency passed through the center of the plasma. The experimental FWCD efficiency was highest at 2 T where the interaction between the fast waves and the beam ions was weakest; as the magnetic field strength was lowered, the FWCD efficiency decreased to approximately half of the maximum theoretical value

Coupling between eddy current and deflection in cantilevered beams in magnetic fields

International Nuclear Information System (INIS)

Hua, T.Q.

1986-01-01

Experiments were performed to investigate the coupling between eddy currents and deflection in cantilevered beams in longitudinal and transverse magnetic fields. This coupling effect reduces the current, deflection, and material stress to levels far less severe than would be predicted if coupling is disregarded. The experiments were conducted using the FELIX (Fusion ELectromagnetic Induction experiment) facility at the Argonne National Laboratory. The beams, which provide a simple model for the limiter blades in a tokamak fusion reactor, are subjected to crossed time-varying and constant magnetic fields. The time-varying field simulates the decaying field during a plasma disruption and the constant field models the toroidal field. Several test pieces are employed to allow variations in thicknesses and mechanical and electrical properties. Various magnetic field levels and decay time constants of time-varying are used to study the extent of the coupling from weak to strong coupling. The ratios of constant field to time-varying field are kept in the range from 10:1 to 20:1 as would be appropriate to tokamak limiters. Major parameters measured as functions of time are beam deflection, measured with an electro-optical device; total circulating current, measured with a Rogowski coil; strain recorded by strain gauges; and magnetic fields measured with Hall probes

Warmer amps for the LHC

CERN Multimedia

Anaïs Schaeffer

2012-01-01

CERN is working together with an Italian company to develop superconducting cables that can function at temperatures of up to 25 K (-248°C). This will make it possible to move LHC magnet power supplies out of the tunnel, protecting them from exposure to the showers of very high-energy particles produced by the accelerator.   Figure 1: devices of this type, which measure approximately 10 metres in length, are inserted between the accelerating magnets at different points along the LHC. When it comes to consuming electricity, the magnets that steer particles through large accelerators can be characterised with just one word: greedy. For the LHC, the total current can reach 1.5 million amps. At the present time, this current is brought in via copper cables of up to 10 cm in diameter. In the tunnel, these cables connect the current leads - which provide the transition between the ambient-temperature cables and the magnets in their bath of superfluid helium - to the power supply. In the a...

Extracellular 2′,3′-cAMP Is a Source of Adenosine*

OpenAIRE

Jackson, Edwin K.; Ren, Jin; Mi, Zaichuan

2009-01-01

We discovered that renal injury releases 2′,3′-cAMP (positional isomer of 3′,5′-cAMP) into the interstitium. This finding motivated a novel hypothesis: renal injury leads to activation of an extracellular 2′,3′-cAMP-adenosine pathway (i.e. metabolism of extracellular 2′,3′-cAMP to 3′-AMP and 2′-AMP, which are metabolized to adenosine, a retaliatory metabolite). In isolated rat kidneys, arterial infusions of 2′,3′-cAMP (30 μmol/liter) increased the mean venous secretion of 3′-AMP (3,400-fold),...

Airborne Multisensor Pod System (AMPS) data management overview

Energy Technology Data Exchange (ETDEWEB)

Wiberg, J.D.; Blough, D.K.; Daugherty, W.R.; Hucks, J.A.; Gerhardstein, L.H.; Meitzler, W.D.; Melton, R.B.; Shoemaker, S.V.

1994-09-01

An overview of the Data Management Plan for the Airborne Multisensor Pod System (AMPS) pro-grain is provided in this document. The Pacific Northwest Laboratory (PNL) has been assigned the responsibility of data management for the program, which includes defining procedures for data management and data quality assessment. Data management is defined as the process of planning, acquiring, organizing, qualifying and disseminating data. The AMPS program was established by the U.S. Department of Energy (DOE), Office of Arms Control and Non-Proliferation (DOE/AN) and is integrated into the overall DOE AN-10.1 technology development program. Sensors used for collecting the data were developed under the on-site inspection, effluence analysis, and standoff sensor program, the AMPS program interacts with other technology programs of DOE/NN-20. This research will be conducted by both government and private industry. AMPS is a research and development program, and it is not intended for operational deployment, although the sensors and techniques developed could be used in follow-on operational systems. For a complete description of the AMPS program, see {open_quotes}Airborne Multisensor Pod System (AMPS) Program Plan{close_quotes}. The primary purpose of the AMPS is to collect high-quality multisensor data to be used in data fusion research to reduce interpretation problems associated with data overload and to derive better information than can be derived from any single sensor. To collect the data for the program, three wing-mounted pods containing instruments with sensors for collecting data will be flight certified on a U.S. Navy RP-3A aircraft. Secondary objectives of the AMPS program are sensor development and technology demonstration. Pod system integrators and instrument developers will be interested in the performance of their deployed sensors and their supporting data acquisition equipment.

A genetic epidemiological mega analysis of smoking initiation in adolescents

NARCIS (Netherlands)

Maes, H.H.; Prom-Wormley, E.; Eaves, L.J.; Rhee, S.H.; Hewitt, J.K.; Young, S.; Corley, R.; McGue, M.K.; Iacono, W.G.; Legrand, L.; Samek, D.; Murrelle, E.L.; Silberg, J.L.; Miles, D.; Schieken, R.M.; Beunen, G.P.; Thomis, M.; Rose, R.J.; Dick, D.M.; Boomsma, D.I.; Bartels, M.; Vink, J.M.; Lichtenstein, P.; White, V.; Kaprio, J.; Neale, M.C.

2017-01-01

Introduction. Previous studies in adolescents were not adequately powered to accurately disentangle genetic and environmental influences on smoking initiation across adolescence. Methods. Mega-analysis of pooled genetically informative data on smoking initiation was performed, with structural

Application of MO-type gapless flange to beam duct for high-current accelerators

International Nuclear Information System (INIS)

Suetsugu, Y.; Shirai, M.; Ohtsuka, M.

2004-01-01

The MO-type flange, which can provide a gapless connection between flanges, was studied experimentally aiming to apply it to the beam duct for high-current accelerators. The test flange showed a good vacuum sealing property, although the aperture had a complicated shape, that is, the combination of a circular beam duct and a rectangular antechamber. The structural analysis well reproduced the observed deformation of flange, and utilized to optimize the structure. The MO-type flange is a promising one for the connection flange of the beam duct for future accelerators. (author)

Mega-rings Surrounding Timber Mountain Nested Calderas, Geophysical Anomalies: Rethinking Structure and Volcanism Near Yucca Mountain (YM), Nevada

Science.gov (United States)

Tynan, M. C.; Smith, K. D.; Savino, J. M.; Vogt, T. J.

2004-12-01

Observed regional mega-rings define a zone ˜80-100 km in diameter centered on Timber Mountain (TM). The mega-rings encompass known smaller rhyolitic nested Miocene calderas ( ˜11-15 my, structural relationships. Mega-rings consist of arcuate faulted blocks with deformation (some remain active structures) patterns showing a genetic relationship to the TM volcanic system; they appear to be spatially associated and temporally correlated with Miocene volcanism and two geophysically identified crustal/upper mantle features. A 50+ km diameter pipe-like high velocity anomaly extends from crustal depth to over 200 km beneath TM (evidence for 400km depth to NE). The pipe is located between two ˜100 km sub-parallel N/S linear trends of small-magnitude earthquake activity, one extending through the central NV Test Site, and a second located near Beatty, NV. Neither the kinematics nor relational mechanism of 100km seismically active N/S linear zones, pipe, and mega-rings are understood. Interpreted mega-rings are: 1) Similar in size to larger terrestrial volcanic complexes (e.g., Yellowstone, Indonesia's Toba system); 2) Located in the region of structural transition from the Mohave block to the south, N/S Basin and Range features to the north, Walker Lane to the NW, and the Las Vegas Valley shear zone to the SE; 3) Associated with the two seismically active zones (similar to other caldera fault-bounded sags), the mantle high velocity feature, and possibly a regional bouguer gravity anomaly; 4) Nearly coincident with area hydrologic basins and sub-basins; 5) Similar to features described from terrestrial and planetary caldera-collapse studies, and as modeled in laboratory scaled investigations (ice melt, balloon/sand). Post Mid-Miocene basalts commonly occur within or adjacent to the older rhyolitic caldera moats; other basaltic material occurs marginal to both the outer rings of the interpreted mega-ring system and high velocity pipe. The YM repository may be situated in

Relation of field-aligned currents measured by AMPERE project to solar wind and substorms

Science.gov (United States)

McPherron, R. L.; Anderson, B. J.; Chu, X.

2016-12-01

Magnetic perturbations measured in the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) by the Iridium constellation of spacecraft have been processed to obtain the time history of field-aligned currents (FAC) connecting the magnetosphere to the ionosphere. We find that the strength of these currents is closely related to the strength of the solar wind driver defined as a running average of the previous three hours of the optimum AL (auroral lower) coupling function. The relation is well represented by a saturation model I = A*S*Ss/(S+Ss) with I the current strength in mega Amps, S the driver strength in mV/m, Ss the saturation value of 7.78 mV/m, and A = 2.55 scales the relation to units of current. We also find that in general the upward current on the nightside increases with each substorm expansion onset defined by a combination of the SuperMag SML (SuperMag AL) and midlatitude positive bay (MPB) onset lists. A superposed epoch analysis using 700 onsets in 2010 shows the following: solar wind coupling peaks at expansion onset; dayside outward current starts to increase one hour before onset while nightside outward current starts suddenly at onset; nightside outward current reaches a peak at 28 minutes as do SML and MPB indices; FAC, SML, and MPB respectively take 1, 2, and 3 hours to decay to background. The data indicate that the substorm current wedge is superposed on a pre-existing field-aligned current system and that the location and properties of the current wedge can be studied with the AMPERE data.

VME computer monitoring system of KEK-PS fast pulsed magnet currents and beam intensities

International Nuclear Information System (INIS)

Kawakubo, T.; Akiyama, A.; Kadokura, E.; Ishida, T.

1992-01-01

For beam transfer from the KEK-PS Linac to the Booster synchrotron ring and from the Booster to the Main ring, many pulse magnets have been installed. It is very important for the machine operation to monitor the firing time, rising time and peak value of the pulsed magnet currents. It is also very important for magnet tuning to obtain good injection efficiency of the Booster and the Main ring, and to observe the last circulating bunched beam in the Booster as well as the first circulating in the Main. These magnet currents and beam intensity signals are digitized by a digital oscilloscope with signal multiplexers, and then shown on a graphic display screen of the console via a VME computer. (author)

Development of high current density neutral beam injector with a low energy for interaction of plasma facing materials

International Nuclear Information System (INIS)

Nishikawa, Masahiro; Ueda, Yoshio; Goto, Seiichi

1991-01-01

A high current density neutral beam injector with a low energy has been developed to investigate interactions with plasma facing materials and propagation processes of damages. The high current density neutral beam has been produced by geometrical focusing method employing a spherical electrode system. The hydrogen beam with the current density of 140 mA/cm 2 has been obtained on the focal point in the case of the acceleration energy of 8 keV. (orig.)

7 CFR 772.10 - Transfer and assumption-AMP loans.

Science.gov (United States)

2010-01-01

... 7 Agriculture 7 2010-01-01 2010-01-01 false Transfer and assumption-AMP loans. 772.10 Section 772..., DEPARTMENT OF AGRICULTURE SPECIAL PROGRAMS SERVICING MINOR PROGRAM LOANS § 772.10 Transfer and assumption—AMP loans. (a) Eligibility. The Agency may approve transfers and assumptions of AMP loans when: (1) The...

Occurrence and detection of AmpC β-lactamases among ...

African Journals Online (AJOL)

Aim of the study: We aimed to evaluate the presence of AmpC β-lactamase among Enterobacteriaceae isolates separated from patients with nosocomial infections, and to detect the genetic basis for AmpC production in these strains. Subjects and methods: 50 AmpC β-lactamase Enterobacteriaceae were analyzed for the ...

Design of a high-current low-energy beam transport line for an intense D-T/D-D neutron generator

International Nuclear Information System (INIS)

Lu, Xiaolong; Wang, Junrun; Zhang, Yu; Li, Jianyi; Xia, Li; Zhang, Jie; Ding, Yanyan; Jiang, Bing; Huang, Zhiwu; Ma, Zhanwen; Wei, Zheng; Qian, Xiangping; Xu, Dapeng; Lan, Changlin; Yao, Zeen

2016-01-01

An intense D-T/D-D neutron generator is currently being developed at the Lanzhou University. The Cockcroft–Walton accelerator, as a part of the neutron generator, will be used to accelerate and transport the high-current low-energy beam from the duoplasmatron ion source to the rotating target. The design of a high-current low-energy beam transport (LEBT) line and the dynamics simulations of the mixed beam were carried out using the TRACK code. The results illustrate that the designed beam line facilitates smooth transportation of a deuteron beam of 40 mA, and the number of undesired ions can be reduced effectively using two apertures.

Increasing the flexibility of the LANCE cAMP detection kit.

Science.gov (United States)

Hunter, Morag Rose; Glass, Michelle

2015-01-01

The detection of cAMP signalling is a common endpoint in the study of G-protein coupled receptors. A number of commercially available kits enable easy detection of cAMP. These kits are based on competition for a cAMP binding site on an antibody or cAMP binding protein and as such have a limited dynamic range. Here, we describe the optimisation of the commercially-available LANCE cAMP detection kit (PerkinElmer) to enable detection in cell lysates. This kit has been designed for use with live cells, with detection reagents applied to cells without wash steps. The standard protocol therefore requires that all assay reagents are compatible with the antibody and the final fluorescent detection stage, limiting the range of assay media and test compounds that can be utilised. The entire experiment must be repeated if cAMP levels fall outside the limited dynamic range. Here we describe a modified protocol that enables the assay to be performed on cell lysates, thereby overcoming these limitations. In this modified protocol, cells are stimulated for a cAMP response in standard media/buffers, washed and then lysed. The cell lysate is then assayed using a modified protocol for the LANCE cAMP detection kit. Samples were tested for stability following a freeze-thaw cycle. The modified LANCE cAMP detection protocol gives a reproducible measurement of cAMP in cell lysate. Lysate samples remain stable when stored at -80°C. Separating the stimulation and detection phases of this cAMP assay allows a vast array of cell stimulation conditions to be tested. The lysate-modified protocol for the LANCE cAMP detection kit therefore increases the flexibility, versatility and convenience of the assay. As samples are insensitive to freeze-thaw, it enables retesting of samples under different dilution conditions to ensure that all samples remain within the dynamic range of the standard curve. Copyright © 2014 Elsevier Inc. All rights reserved.

The Popeye Domain Containing Genes and cAMP Signaling

Directory of Open Access Journals (Sweden)

Thomas Brand

2014-05-01

Full Text Available 3'-5'-cyclic adenosine monophosphate (cAMP is a second messenger, which plays an important role in the heart. It is generated in response to activation of G-protein-coupled receptors (GPCRs. Initially, it was thought that protein kinase A (PKA exclusively mediates cAMP-induced cellular responses such as an increase in cardiac contractility, relaxation, and heart rate. With the identification of the exchange factor directly activated by cAMP (EPAC and hyperpolarizing cyclic nucleotide-gated (HCN channels as cAMP effector proteins it became clear that a protein network is involved in cAMP signaling. The Popeye domain containing (Popdc genes encode yet another family of cAMP-binding proteins, which are prominently expressed in the heart. Loss-of-function mutations in mice are associated with cardiac arrhythmia and impaired skeletal muscle regeneration. Interestingly, the cardiac phenotype, which is present in both, Popdc1 and Popdc2 null mutants, is characterized by a stress-induced sinus bradycardia, suggesting that Popdc proteins participate in cAMP signaling in the sinuatrial node. The identification of the two-pore channel TREK-1 and Caveolin 3 as Popdc-interacting proteins represents a first step into understanding the mechanisms of heart rate modulation triggered by Popdc proteins.

Intrusion Detection amp Prevention Systems - Sourcefire Snort

Directory of Open Access Journals (Sweden)

Rajesh Vuppala

2015-08-01

Full Text Available Information security is a challenging issue for all business organizations today amidst increasing cyber threats. While there are many alternative intrusion detection amp prevention systems available to choose from selecting the best solution to implement to detect amp prevent cyber-attacks is a difficult task. The best solution is of the one that gets the best reviews and suits the organizations needs amp budget. In this review paper we summarize various classes of intrusion detection and prevention systems compare features of alternative solutions and make recommendation for implementation of one as the best solution for business organization in Fiji.

Beam current transformer (BCT) for experiment WA1/2

CERN Multimedia

CERN PhotoLab

1978-01-01

In experiment WA1/2, a 400 GeV proton beam from the SPS was directed at a target, downstream of which a hadron line selected, in several narrow momentum bands, a beam of either pi+ and K+ or pi- and K-. These neutrino-parent particles, before entering a 292 m long decay tunnel, passed through a set of 2 BCTs of a design seen here. They measured the hadron intensity (10^10 to 10^11 particles/pulse) with a precision of the order of 1%. There were 2 of them, for enhanced precision and confidence. After the discovery of neutral currents in the Gargamelle-experiment, WA1/2 was the first follow-up, high-precision experiment (Z.Phys.C35, 443-452, 1987 and Z.Phys.C45, 361-379, 1990). See also 7706516X.

Dynamics of a relativistic electron beam in a high-current diode with a knife-edge cathode

International Nuclear Information System (INIS)

Babykin, V.M.; Gordeev, A.V.; Golovin, G.T.; Korolev, V.D.; Kopchikov, A.V.; Tulupov, M.V.; Chernenko, A.S.; Shuvaev, V.Yu.

1991-01-01

For a number of practical applications, e.g., producing discharges in large volumes in order to pump gas lasers and for short x-ray pulses, it is necessary to generate electron beams in megamp range with electron energies from hundreds of kilovolts to several megavolts. It has been possible to obtain high currents (I ± 1 MA) by using diodes with knife-edge cathodes. Knife-edge diodes have an important advantage over the parapotential type because the ion current in them comprises a relatively small fraction of the total current. This is because the electron path in the accelerating gap of knife-edge diodes is quite short in comparison with that in high-current parapotential diodes. From the point of view of applying ribbon-shaped or narrow electron beams, the important problems are in measuring the current-voltage characteristics of the diodes and determining the dynamics of the energy spectrum and the angular spread of the electrons. The generation of an electron beam with a current ∼130 kA and pulse length ∼60 ns is studied. The current-voltage characteristics of knife-edge diodes with various geometries, the dynamics of the angular spread, and the beam structure are studied. As a result of the study of the REB dynamics it is found that the operation of the diode with these experiments can be approximated by a proposed formula which includes the finite thickness of the knife-edge cathode and the motion of the plasma and ions in the discharge gap. Breaking up of the beam into individual current-carrying channels is observed with the characteristic scale ∼1-2 mm. It is noted that for the diode geometry with a knife-edge cathode, when the magnetic field changes sign and passes through zero, an instability can exist which is analogous to the dissipative tearing instability

AMP-18 Targets p21 to Maintain Epithelial Homeostasis.

Science.gov (United States)

Chen, Peili; Li, Yan Chun; Toback, F Gary

2015-01-01

Dysregulated homeostasis of epithelial cells resulting in disruption of mucosal barrier function is an important pathogenic mechanism in inflammatory bowel diseases (IBD). We have characterized a novel gastric protein, Antrum Mucosal Protein (AMP)-18, that has pleiotropic properties; it is mitogenic, anti-apoptotic and can stimulate formation of tight junctions. A 21-mer synthetic peptide derived from AMP-18 exhibits the same biological functions as the full-length protein and is an effective therapeutic agent in mouse models of IBD. In this study we set out to characterize therapeutic mechanisms and identify molecular targets by which AMP-18 maintains and restores disrupted epithelial homeostasis in cultured intestinal epithelial cells and a mouse model of IBD. Tumor necrosis factor (TNF)-α, a pro-inflammatory cytokine known to mediate gastrointestinal (GI) mucosal injury in IBD, was used to induce intestinal epithelial cell injury, and study the effects of AMP-18 on apoptosis and the cell cycle. An apoptosis array used to search for targets of AMP-18 in cells exposed to TNF-α identified the cyclin-dependent kinase inhibitor p21 WAF1/CIP1. Treatment with AMP-18 blunted increases in p21 expression and apoptosis, while reversing disturbed cell cycle kinetics induced by TNF-α. AMP-18 appears to act through PI3K/AKT pathways to increase p21 phosphorylation, thereby reducing its nuclear accumulation to overcome the antiproliferative effects of TNF-α. In vitamin D receptor-deficient mice with TNBS-induced IBD, the observed increase in p21 expression in colonic epithelial cells was suppressed by treatment with AMP peptide. The results indicate that AMP-18 can maintain and/or restore the homeostatic balance between proliferation and apoptosis in intestinal epithelial cells to protect and repair mucosal barrier homeostasis and function, suggesting a therapeutic role in IBD.

AMP-18 Targets p21 to Maintain Epithelial Homeostasis.

Directory of Open Access Journals (Sweden)

Peili Chen

Full Text Available Dysregulated homeostasis of epithelial cells resulting in disruption of mucosal barrier function is an important pathogenic mechanism in inflammatory bowel diseases (IBD. We have characterized a novel gastric protein, Antrum Mucosal Protein (AMP-18, that has pleiotropic properties; it is mitogenic, anti-apoptotic and can stimulate formation of tight junctions. A 21-mer synthetic peptide derived from AMP-18 exhibits the same biological functions as the full-length protein and is an effective therapeutic agent in mouse models of IBD. In this study we set out to characterize therapeutic mechanisms and identify molecular targets by which AMP-18 maintains and restores disrupted epithelial homeostasis in cultured intestinal epithelial cells and a mouse model of IBD. Tumor necrosis factor (TNF-α, a pro-inflammatory cytokine known to mediate gastrointestinal (GI mucosal injury in IBD, was used to induce intestinal epithelial cell injury, and study the effects of AMP-18 on apoptosis and the cell cycle. An apoptosis array used to search for targets of AMP-18 in cells exposed to TNF-α identified the cyclin-dependent kinase inhibitor p21 WAF1/CIP1. Treatment with AMP-18 blunted increases in p21 expression and apoptosis, while reversing disturbed cell cycle kinetics induced by TNF-α. AMP-18 appears to act through PI3K/AKT pathways to increase p21 phosphorylation, thereby reducing its nuclear accumulation to overcome the antiproliferative effects of TNF-α. In vitamin D receptor-deficient mice with TNBS-induced IBD, the observed increase in p21 expression in colonic epithelial cells was suppressed by treatment with AMP peptide. The results indicate that AMP-18 can maintain and/or restore the homeostatic balance between proliferation and apoptosis in intestinal epithelial cells to protect and repair mucosal barrier homeostasis and function, suggesting a therapeutic role in IBD.

Vehicle charging and return current measurements during electron-beam emission experiments from the Shuttle Orbiter

International Nuclear Information System (INIS)

Hawkins, J.G.

1988-01-01

The prime objective of this research was to investigate the electro-dynamic response of the Shuttle Orbiter during electron beam emission from the payload bay. This investigation has been conducted by examining data collected by the Vehicle Charging And Potential (VCAP) Experiment. The VCAP experiment has flown on two Shuttle missions with a Fast Pulse Electron Generator (FPEG) capable of emitting a 100 mA beam of 1 keV electrons. Diagnostics of the charging and return current during beam emission were provided by a combined Charge and Current Probe (CCP) located in the payload bay of the Orbiter. The CCP measurements were used to conduct a parametric study of the vehicle charging and return current as a function of vehicle attitude, ambient plasma parameters, and emitted beam current. In particular, the CCP measurements were found to depend strongly on the ambient plasma density. The vehicle charging during a 100 mA beam emission was small when the predicted ambient plasma density was greater than 3 x 10 5 cm -3 , but appreciable charging occurred when the density was less than this value. These observations indicated that the effective current-collecting area of the Orbiter is approximately 42 m 2 , consistent with estimates for the effective area of the Orbiter's engine nozzles. The operation of the Orbiter's Reaction Control System thrusters can create perturbations in the Orbiter's neutral and plasma environment that affect the CCP measurements. The CCP signatures of thruster firings are quite complex, but in general they are consistent with the depletion of plasma density in the ram direction and the enhancement of plasma density in the Orbiter's wake

“Corte Transversal”: una mega escultura entre el río Mapocho y la autopista Costanera Norte en Santiago de Chile/ “Corte Transversal”: a mega sculpture between the Mapocho River and the Costanera Norte toll road in Santiago de Chile

Directory of Open Access Journals (Sweden)

Revista de Urbanismo, Departamento de Urbanismo de la Facultad de Arquitectura y Urbanismo de la Universidad de Chile. (Reportaje de M.I.PavezR.- M.P.Henríquez.O

2008-12-01

Full Text Available “Corte Transversal”: una mega escultura entre el río Mapocho y la autopista Costanera Norte en Santiago de Chile/“Corte Transversal”: a mega sculpture between the Mapocho River and the Costanera Norte toll road in Santiago de Chile

Depletion region surface effects in electron beam induced current measurements

Energy Technology Data Exchange (ETDEWEB)

Haney, Paul M.; Zhitenev, Nikolai B. [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Yoon, Heayoung P. [Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112 (United States); Gaury, Benoit [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Maryland NanoCenter, University of Maryland, College Park, Maryland 20742 (United States)

2016-09-07

Electron beam induced current (EBIC) is a powerful characterization technique which offers the high spatial resolution needed to study polycrystalline solar cells. Current models of EBIC assume that excitations in the p-n junction depletion region result in perfect charge collection efficiency. However, we find that in CdTe and Si samples prepared by focused ion beam (FIB) milling, there is a reduced and nonuniform EBIC lineshape for excitations in the depletion region. Motivated by this, we present a model of the EBIC response for excitations in the depletion region which includes the effects of surface recombination from both charge-neutral and charged surfaces. For neutral surfaces, we present a simple analytical formula which describes the numerical data well, while the charged surface response depends qualitatively on the location of the surface Fermi level relative to the bulk Fermi level. We find that the experimental data on FIB-prepared Si solar cells are most consistent with a charged surface and discuss the implications for EBIC experiments on polycrystalline materials.

Development of a high-current ion source with slit beam extraction for neutral beam injector of VEST

Energy Technology Data Exchange (ETDEWEB)

Jung, Bong-ki; Chung, Kyoung-Jae, E-mail: jkjlsh1@snu.ac.kr; An, Young-Hwa; Park, Jong-Yoon; Hwang, Y.S.

2015-10-15

Highlights: • A high-current ion source is developed for NBI system of VEST. • A cold-cathode electron gun is employed to produce primary electrons. • A hemi-cylindrical discharge chamber with cusp magnetic field is used. • Plasma density is measured to be 2 × 10{sup 18} m{sup −3} near the extraction aperture. • NBI power of 90 kW with beam energy of 20 keV is expected to be achieved. - Abstract: A high-current pulsed ion source has been developed for the neutral beam injector of the VEST (Versatile Experiment Spherical Torus) to accommodate high-beta fusion plasma experiments. The ion source consists of two parts: an electron gun for supplying sufficient primary electrons by cold-cathode arc discharge and a hemi-cylindrical discharge chamber where uniform, high-density plasma generated by the primary electrons is confined by multi-cusp magnetic field. A pulse forming network is also developed to drive high current of ∼1 kA to sustain the cold-cathode discharge in the electron gun up to 10 ms. Diagnostics with a triple probe in the discharge chamber shows that a hydrogen plasma whose density is as high as 1 × 10{sup 18} m{sup −3} can be obtained near extraction slits at the gas pressure lower than 0.5 Pa. This value is estimated to be sufficient to deposit a heating power of 90 kW to the VEST plasma when the appropriate extraction through slits with 20 cm{sup 2} in area and acceleration of ion beams up to 20 kV are fulfilled.

Reduction of extended-spectrum-β-lactamase- and AmpC-β-lactamase-producing Escherichia coli through processing in two broiler chicken slaughterhouses

NARCIS (Netherlands)

Pacholewicz, Ewa; Liakopoulos, Apostolos; Swart, Arno; Gortemaker, Betty; Dierikx, Cindy; Havelaar, Arie|info:eu-repo/dai/nl/072306122; Schmitt, Heike|info:eu-repo/dai/nl/304831042

2015-01-01

Whilst broilers are recognised as a reservoir of extended-spectrum-β-lactamase (ESBL)- and AmpC-β-lactamase (AmpC)-producing Escherichia coli, there is currently limited knowledge on the effect of slaughtering on its concentrations on poultry meat. The aim of this study was to establish the

Reduction of extended-spectrum-β-lactamase- and AmpC-β-lactamase-producing Escherichia coli through processing in two broiler chicken slaughterhouses

NARCIS (Netherlands)

Pacholewicz, Ewa; Liakopoulos, Apostolos; Swart, Arno; Gortemaker, Betty; Dierikx, Cindy; Havelaar, Arie; Schmitt, Heike

2015-01-01

Whilst broilers are recognised as a reservoir of extended-spectrum-β-lactamase (ESBL)- and AmpC-β-lactamase (AmpC)-producing Escherichia coli, there is currently limited knowledge on the effect of slaughtering on its concentrations on poultry meat. The aim of this study was to establish the

Parameters affecting profile shape of a high energy low current thin ion beam. Vol. 2