Science.gov

Sample records for accelerator systems string

  1. Vibration monitoring system for drill string

    SciTech Connect

    Wassell, M.E.

    1993-07-13

    A vibration monitoring system is described for use in monitoring lateral and torsional vibrations in a drill string comprising: a drill string component having an outer surface; first accelerometer means A[sub 1] for measuring tangential acceleration; second accelerometer means A[sub 2] for measuring tangential acceleration; third accelerometer means A[sub 3] for measuring tangential acceleration; said first, second and third accelerometer means A[sub 1], A[sub 2] and A[sub 3] being mounted in said drill string component and being spaced from one another to measure acceleration forces on said drill string component tangentially with respect to the outer surface of said component wherein said first, second and third accelerometer means are adapted to measure and distinguish between lateral and torsional vibrations exerted on said drill string component.

  2. Hydroball string sensing system

    DOEpatents

    Hurwitz, Michael J.; Ekeroth, Douglas E.; Squarer, David

    1991-01-01

    A hydroball string sensing system for a nuclear reactor that includes stainless tubes positioned to guide hydroball strings into and out of the nuclear reactor core. A sensor such as an ultrasonic transducer transmitter and receiver is positioned outside of the nuclear reactor core and adjacent to the tube. The presence of an object such a bullet member positioned at an end a hydroball string, or any one of the hydroballs interrupts the transmission of ultrasound from the transmitter to the receiver. Alternatively, if the bullet member and hydroballs include a ferritic material, either a Hall effect sensor or other magnetic field sensors such as a magnetic field rate of change sensor can be used to detect the location and position of a hydroball string. Placing two sensors along the tube with a known distance between the sensors enables the velocity of a hydroball string to be determined. This determined velocity can be used to control the flow rate of a fluid within the tube so as to control the velocity of the hydroball string.

  3. Single String Integration Test of the High Voltage Hall Accelerator System

    NASA Technical Reports Server (NTRS)

    Kamhawi, Hani; Haag, Thomas W.; Huang, Wensheng; Pinero, Luis; Peterson, Todd; Shastry, Rohit

    2013-01-01

    HiVHAc Task Objectives:-Develop and demonstrate low-power, long-life Hall thruster technology to enable cost effective EP for Discovery-class missions-Advance the TRL level of potential power processing units and xenon feed systems to integrate with the HiVHAc thruster.

  4. Multilayer insulation for the interconnect region in the Accelerator System String Test: A practical engineering approach for a new scheme of design and installation bridges

    SciTech Connect

    Baritchi, D.; Jalloh, A.

    1993-04-01

    In order to minimize the heat leak in the Accelerator System String Test (ASST) inter-connect region, shield bridges and multilayer insulation (MLI) are provided. A sliding joint between shield bridges on adjacent magnets accommodates the contraction that occurs during cooldown. In the original design of the MLI bridges, thermal contraction was provided for by compressing the MLI. During assembly of the interconnect region, it was realized that there was not enough room for the required compression. This resulted in a redesign of the MLI bridges. The new scheme involves splitting and overlapping the MLI. This scheme has worked very well in subsequent assembly of the interconnect region. In this paper, we are going to present the new design scheme. We will also compare this design with the original design and present its advantages.

  5. Electron string ion sources for carbon ion cancer therapy accelerators.

    PubMed

    Boytsov, A Yu; Donets, D E; Donets, E D; Donets, E E; Katagiri, K; Noda, K; Ponkin, D O; Ramzdorf, A Yu; Salnikov, V V; Shutov, V B

    2015-08-01

    The type of the Electron String Ion Sources (ESIS) is considered to be the appropriate one to produce pulsed C(4+) and C(6+) ion beams for cancer therapy accelerators. In fact, the new test ESIS Krion-6T already now provides more than 10(10) C(4+) ions per pulse and about 5 × 10(9) C(6+) ions per pulse. Such ion sources could be suitable to apply at synchrotrons. It has also been found that Krion-6T can provide more than 10(11) C(6+) ions per second at the 100 Hz repetition rate, and the repetition rate can be increased at the same or larger ion output per second. This makes ESIS applicable at cyclotrons as well. ESIS can be also a suitable type of ion source to produce the (11)C radioactive ion beams. A specialized cryogenic cell was experimentally tested at the Krion-2M ESIS for pulse injection of gaseous species into the electron string. It has been shown in experiments with stable methane that the total conversion efficiency of methane molecules to C(4+) ions reached 5%÷10%. For cancer therapy with simultaneous irradiation and precise dose control (positron emission tomography) by means of (11)C, transporting to the tumor with the primary accelerated (11)C(4+) beam, this efficiency is preliminarily considered to be large enough to produce the (11)C(4+) beam from radioactive methane and to inject this beam into synchrotrons.

  6. Electron string ion sources for carbon ion cancer therapy accelerators.

    PubMed

    Boytsov, A Yu; Donets, D E; Donets, E D; Donets, E E; Katagiri, K; Noda, K; Ponkin, D O; Ramzdorf, A Yu; Salnikov, V V; Shutov, V B

    2015-08-01

    The type of the Electron String Ion Sources (ESIS) is considered to be the appropriate one to produce pulsed C(4+) and C(6+) ion beams for cancer therapy accelerators. In fact, the new test ESIS Krion-6T already now provides more than 10(10) C(4+) ions per pulse and about 5 × 10(9) C(6+) ions per pulse. Such ion sources could be suitable to apply at synchrotrons. It has also been found that Krion-6T can provide more than 10(11) C(6+) ions per second at the 100 Hz repetition rate, and the repetition rate can be increased at the same or larger ion output per second. This makes ESIS applicable at cyclotrons as well. ESIS can be also a suitable type of ion source to produce the (11)C radioactive ion beams. A specialized cryogenic cell was experimentally tested at the Krion-2M ESIS for pulse injection of gaseous species into the electron string. It has been shown in experiments with stable methane that the total conversion efficiency of methane molecules to C(4+) ions reached 5%÷10%. For cancer therapy with simultaneous irradiation and precise dose control (positron emission tomography) by means of (11)C, transporting to the tumor with the primary accelerated (11)C(4+) beam, this efficiency is preliminarily considered to be large enough to produce the (11)C(4+) beam from radioactive methane and to inject this beam into synchrotrons. PMID:26329182

  7. Spontaneous excitation of a uniformly accelerated atom in the cosmic string spacetime

    NASA Astrophysics Data System (ADS)

    Zhou, Wenting; Yu, Hongwei

    2016-04-01

    We study, in the cosmic string spacetime, the average rate of change of energy for an atom coupled to massless scalar fields and uniformly accelerated in a direction parallel to the string in vacuum. We find that both the noninertial motion and the nontrivial global spacetime topology affect the atomic transition rates, so an accelerated atom (an Unruh detector) does feel the string contrary to claims in the literature. We demonstrate that the equivalence between the effect of uniform acceleration and that of thermal radiation on the transition rates of the atom, which is valid in the Minkowski spacetime, holds only on the string.

  8. Electron string ion sources for carbon ion cancer therapy accelerators

    SciTech Connect

    Boytsov, A. Yu.; Donets, D. E.; Donets, E. D.; Donets, E. E.; Ponkin, D. O.; Ramzdorf, A. Yu.; Salnikov, V. V.; Shutov, V. B.; Katagiri, K.; Noda, K.

    2015-08-15

    The type of the Electron String Ion Sources (ESIS) is considered to be the appropriate one to produce pulsed C{sup 4+} and C{sup 6+} ion beams for cancer therapy accelerators. In fact, the new test ESIS Krion-6T already now provides more than 10{sup 10} C{sup 4+} ions per pulse and about 5 × 10{sup 9} C{sup 6+} ions per pulse. Such ion sources could be suitable to apply at synchrotrons. It has also been found that Krion-6T can provide more than 10{sup 11} C{sup 6+} ions per second at the 100 Hz repetition rate, and the repetition rate can be increased at the same or larger ion output per second. This makes ESIS applicable at cyclotrons as well. ESIS can be also a suitable type of ion source to produce the {sup 11}C radioactive ion beams. A specialized cryogenic cell was experimentally tested at the Krion-2M ESIS for pulse injection of gaseous species into the electron string. It has been shown in experiments with stable methane that the total conversion efficiency of methane molecules to C{sup 4+} ions reached 5%÷10%. For cancer therapy with simultaneous irradiation and precise dose control (positron emission tomography) by means of {sup 11}C, transporting to the tumor with the primary accelerated {sup 11}C{sup 4+} beam, this efficiency is preliminarily considered to be large enough to produce the {sup 11}C{sup 4+} beam from radioactive methane and to inject this beam into synchrotrons.

  9. Accelerating Real-Time String Searching with Multicore Processors

    SciTech Connect

    Villa, Oreste; Scarpazza, Daniele P.; Petrini, Fabrizio

    2008-04-01

    String searching is at the core of tools used to search, filter, and protect data, but this has become increasingly difficult to do in real time as communication speed grows. The authors present an optimization strategy for a popular algorithm that fully exploits the IBM Cell Broadband Engine architecture to perform exact string matching against large dictionaries and also offer various solutions to alleviate memory congestion.

  10. Match-bounded String Rewriting Systems

    NASA Technical Reports Server (NTRS)

    Geser, Alfons; Hofbauer, Dieter; Waldmann, Johannes

    2003-01-01

    We introduce a new class of automated proof methods for the termination of rewriting systems on strings. The basis of all these methods is to show that rewriting preserves regular languages. To this end, letters are annotated with natural numbers, called match heights. If the minimal height of all positions in a redex is h+1 then every position in the reduct will get height h+1. In a match-bounded system, match heights are globally bounded. Using recent results on deleting systems, we prove that rewriting by a match-bounded system preserves regular languages. Hence it is decidable whether a given rewriting system has a given match bound. We also provide a sufficient criterion for the abence of a match-bound. The problem of existence of a match-bound is still open. Match-boundedness for all strings can be used as an automated criterion for termination, for match-bounded systems are terminating. This criterion can be strengthened by requiring match-boundedness only for a restricted set of strings, for instance the set of right hand sides of forward closures.

  11. Accelerator system and method of accelerating particles

    NASA Technical Reports Server (NTRS)

    Wirz, Richard E. (Inventor)

    2010-01-01

    An accelerator system and method that utilize dust as the primary mass flux for generating thrust are provided. The accelerator system can include an accelerator capable of operating in a self-neutralizing mode and having a discharge chamber and at least one ionizer capable of charging dust particles. The system can also include a dust particle feeder that is capable of introducing the dust particles into the accelerator. By applying a pulsed positive and negative charge voltage to the accelerator, the charged dust particles can be accelerated thereby generating thrust and neutralizing the accelerator system.

  12. String Stability of a Linear Formation Flight Control System

    NASA Technical Reports Server (NTRS)

    Allen, Michael J.; Ryan, Jack; Hanson, Curtis E.; Parle, James F.

    2002-01-01

    String stability analysis of an autonomous formation flight system was performed using linear and nonlinear simulations. String stability is a measure of how position errors propagate from one vehicle to another in a cascaded system. In the formation flight system considered here, each i(sup th) aircraft uses information from itself and the preceding ((i-1)(sup th)) aircraft to track a commanded relative position. A possible solution for meeting performance requirements with such a system is to allow string instability. This paper explores two results of string instability and outlines analysis techniques for string unstable systems. The three analysis techniques presented here are: linear, nonlinear formation performance, and ride quality. The linear technique was developed from a worst-case scenario and could be applied to the design of a string unstable controller. The nonlinear formation performance and ride quality analysis techniques both use nonlinear formation simulation. Three of the four formation-controller gain-sets analyzed in this paper were limited more by ride quality than by performance. Formations of up to seven aircraft in a cascaded formation could be used in the presence of light gusts with this string unstable system.

  13. Ion beam accelerator system

    NASA Technical Reports Server (NTRS)

    Aston, G. (Inventor)

    1981-01-01

    A system is described that combines geometrical and electrostatic focusing to provide high ion extraction efficiency and good focusing of an accelerated ion beam. The apparatus includes a pair of curved extraction grids with multiple pairs of aligned holes positioned to direct a group of beamlets along converging paths. The extraction grids are closely spaced and maintained at a moderate potential to efficiently extract beamlets of ions and allow them to combine into a single beam. An accelerator electrode device downstream from the extraction grids is at a much lower potential than the grids to accelerate the combined beam. The application of the system to ion implantation is mentioned.

  14. A string matching computer-assisted system for dolphin photoidentification.

    PubMed

    Araabi, B N; Kehtarnavaz, N; McKinney, T; Hillman, G; Würsig, B

    2000-01-01

    This paper presents a syntactic/semantic string representation scheme as well as a string matching method as part of a computer-assisted system to identify dolphins from photographs of their dorsal fins. A low-level string representation is constructed from the curvature function of a dolphin's fin trailing edge, consisting of positive and negative curvature primitives. A high-level string representation is then built over the low-level string via merging appropriate groupings of primitives in order to have a less sensitive representation to curvature fluctuations or noise. A family of syntactic/semantic distance measures between two strings is introduced. A composite distance measure is then defined and used as a dissimilarity measure for database search, highlighting both the syntax (structure or sequence) and semantic (attribute or feature) differences. The syntax consists of an ordered sequence of significant protrusions and intrusions on the edge, while the semantics consist of seven attributes extracted from the edge and its curvature function. The matching results are reported for a database of 624 images corresponding to 164 individual dolphins. The identification results indicate that the developed string matching method performs better than the previous matching methods including dorsal ratio, curvature, and curve matching. The developed computer-assisted system can help marine mammalogists in their identification of dolphins, since it allows them to examine only a handful of candidate images instead of the currently used manual searching of the entire database. PMID:11144987

  15. Ion beam accelerator system

    NASA Technical Reports Server (NTRS)

    Aston, Graeme (Inventor)

    1984-01-01

    A system is described that combines geometrical and electrostatic focusing to provide high ion extraction efficiency and good focusing of an accelerated ion beam. The apparatus includes a pair of curved extraction grids (16, 18) with multiple pairs of aligned holes positioned to direct a group of beamlets (20) along converging paths. The extraction grids are closely spaced and maintained at a moderate potential to efficiently extract beamlets of ions and allow them to combine into a single beam (14). An accelerator electrode device (22) downstream from the extraction grids, is at a much lower potential than the grids to accelerate the combined beam.

  16. String-fluid transition in systems with aligned anisotropic interactions.

    PubMed

    Brandt, P C; Ivlev, A V; Morfill, G E

    2010-06-21

    Systems with aligned anisotropic interactions between particles exhibit numerous phase transitions. A remarkable example of the fluid phase transition occurring in such systems is the formation of particle strings--the so-called "string" or "chain" fluids. We employ an approach based on the Ornstein-Zernike (OZ) equation, which allows us to calculate structural properties of fluids with aligned anisotropic interactions. We show that the string-fluid transition can be associated with the bifurcation of the "isotropic" correlation length into two distinct scales which characterize the longitudinal and transverse order in string fluids and, hence, may be used as a fingerprint of this transition. The comparison of the proposed OZ theory with the Monte Carlo simulations reveals fairly good agreement.

  17. String-fluid transition in systems with aligned anisotropic interactions.

    PubMed

    Brandt, P C; Ivlev, A V; Morfill, G E

    2010-06-21

    Systems with aligned anisotropic interactions between particles exhibit numerous phase transitions. A remarkable example of the fluid phase transition occurring in such systems is the formation of particle strings--the so-called "string" or "chain" fluids. We employ an approach based on the Ornstein-Zernike (OZ) equation, which allows us to calculate structural properties of fluids with aligned anisotropic interactions. We show that the string-fluid transition can be associated with the bifurcation of the "isotropic" correlation length into two distinct scales which characterize the longitudinal and transverse order in string fluids and, hence, may be used as a fingerprint of this transition. The comparison of the proposed OZ theory with the Monte Carlo simulations reveals fairly good agreement. PMID:20572736

  18. Microgravity Acceleration Measurement System

    NASA Technical Reports Server (NTRS)

    Foster, William

    2009-01-01

    Microgravity Acceleration Measurement System (MAMS) is an ongoing study of the small forces (vibrations and accelerations) on the ISS that result from the operation of hardware, crew activities, as well as dockings and maneuvering. Results will be used to generalize the types of vibrations affecting vibration-sensitive experiments. Investigators seek to better understand the vibration environment on the space station to enable future research.

  19. String theory as a diffusing system

    NASA Astrophysics Data System (ADS)

    Calcagni, Gianluca; Nardelli, Giuseppe

    2010-02-01

    Recent results on the effective non-local dynamics of the tachyon mode of open string field theory (OSFT) show that approximate solutions can be constructed which obey the diffusion equation. We argue that this structure is inherited from the full theory, where it admits a universal formulation. In fact, all known exact OSFT solutions are superpositions of diffusing surface states. In particular, the diffusion equation is a spacetime manifestation of OSFT gauge symmetries.

  20. Gravitational radiation from rotating monopole-string systems

    SciTech Connect

    Babichev, E.; Dokuchaev, V.; Kachelriess, M.

    2005-02-15

    We study the gravitational radiation from a rotating monopole-antimonopole pair connected by a string. While at not too high frequencies the emitted gravitational spectrum is described asymptotically by P{sub n}{proportional_to}n{sup -1}, the spectrum is exponentially suppressed in the high-frequency limit, P{sub n}{proportional_to}exp(-n/n{sub cr}). Below n{sub cr}, the emitted spectrum of gravitational waves is very similar to the case of an oscillating monopole pair connected by a string, and we argue, therefore, that the spectrum found holds approximately for any moving monopole-string system. As an application, we discuss the stochastic gravitational wave background generated by monopole-antimonopole pairs connected by strings in the early Universe and gravitational wave bursts emitted at present by monopole-string networks. We confirm that advanced gravitational wave detectors have the potential to detect a signal for string tensions as small as G{mu}{approx}10{sup -13}.

  1. Resonant acoustic transducer and driver system for a well drilling string communication system

    DOEpatents

    Chanson, Gary J.; Nicolson, Alexander M.

    1981-01-01

    The acoustic data communication system includes an acoustic transmitter and receiver wherein low frequency acoustic waves, propagating in relatively loss free manner in well drilling string piping, are efficiently coupled to the drill string and propagate at levels competitive with the levels of noise generated by drilling machinery also present in the drill string. The transmitting transducer incorporates a mass-spring piezoelectric transmitter and amplifier combination that permits self-oscillating resonant operation in the desired low frequency range.

  2. RFQ accelerator tuning system

    DOEpatents

    Bolie, Victor W.

    1990-01-01

    A cooling system is provided for maintaining a preselected operating temperature in a device, which may be an RFQ accelerator, having a variable heat removal requirement, by circulating a cooling fluid through a cooling system remote from the device. Internal sensors in the device enable an estimated error signal to be generated from parameters which are indicative of the heat removal requirement from the device. Sensors are provided at predetermined locations in the cooling system for outputting operational temperature signals. Analog and digital computers define a control signal functionally related to the temperature signals and the estimated error signal, where the control signal is defined effective to return the device to the preselected operating temperature in a stable manner. The cooling system includes a first heat sink responsive to a first portion of the control signal to remove heat from a major portion of the circulating fluid. A second heat sink is responsive to a second portion of the control signal to remove heat from a minor portion of the circulating fluid. The cooled major and minor portions of the circulating fluid are mixed in response to a mixing portion of the control signal, which is effective to proportion the major and minor portions of the circulating fluid to establish a mixed fluid temperature which is effective to define the preselected operating temperature for the remote device. In an RFQ environment the stable temperature control enables the resonant frequency of the device to be maintained at substantially a predetermined value during transient operations.

  3. RFQ accelerator tuning system

    DOEpatents

    Bolie, V.W.

    1990-07-03

    A cooling system is provided for maintaining a preselected operating temperature in a device, which may be an RFQ accelerator, having a variable heat removal requirement, by circulating a cooling fluid through a cooling system remote from the device. Internal sensors in the device enable an estimated error signal to be generated from parameters which are indicative of the heat removal requirement from the device. Sensors are provided at predetermined locations in the cooling system for outputting operational temperature signals. Analog and digital computers define a control signal functionally related to the temperature signals and the estimated error signal, where the control signal is defined effective to return the device to the preselected operating temperature in a stable manner. The cooling system includes a first heat sink responsive to a first portion of the control signal to remove heat from a major portion of the circulating fluid. A second heat sink is responsive to a second portion of the control signal to remove heat from a minor portion of the circulating fluid. The cooled major and minor portions of the circulating fluid are mixed in response to a mixing portion of the control signal, which is effective to proportion the major and minor portions of the circulating fluid to establish a mixed fluid temperature which is effective to define the preselected operating temperature for the remote device. In an RFQ environment the stable temperature control enables the resonant frequency of the device to be maintained at substantially a predetermined value during transient operations. 3 figs.

  4. Deciding Termination for Ancestor Match- Bounded String Rewriting Systems

    NASA Technical Reports Server (NTRS)

    Geser, Alfons; Hofbauer, Dieter; Waldmann, Johannes

    2005-01-01

    Termination of a string rewriting system can be characterized by termination on suitable recursively defined languages. This kind of termination criteria has been criticized for its lack of automation. In an earlier paper we have shown how to construct an automated termination criterion if the recursion is aligned with the rewrite relation. We have demonstrated the technique with Dershowitz's forward closure criterion. In this paper we show that a different approach is suitable when the recursion is aligned with the inverse of the rewrite relation. We apply this idea to Kurth's ancestor graphs and obtain ancestor match-bounded string rewriting systems. Termination is shown to be decidable for this class. The resulting method improves upon those based on match-boundedness or inverse match-boundedness.

  5. String order via Floquet interactions in atomic systems

    NASA Astrophysics Data System (ADS)

    Lee, Tony E.; Joglekar, Yogesh N.; Richerme, Philip

    2016-08-01

    We study the transverse-field Ising model with interactions that are modulated in time. In a rotating frame, the system is described by a time-independent Hamiltonian with many-body interactions, similar to the cluster Hamiltonians of measurement-based quantum computing. In one dimension, there is a three-body interaction, which leads to string order instead of conventional magnetic order. We show that the string order is robust to power-law interactions that decay with the cube of distance. In two and three dimensions, there are five- and seven-body interactions. We discuss adiabatic preparation of the ground state as well as experimental implementation with trapped ions, Rydberg atoms, and polar molecules.

  6. Controlled synthesis of target strings in a class of splicing systems.

    PubMed

    Chen, Peter C Y

    2005-08-01

    This article presents an approach for synthesizing target strings in a class of computational models of DNA recombination. The computational models are formalized as splicing systems in the context of formal languages. Given a splicing system (of a restricted type) and a target string to be synthesized, we construct (i) a rule-embedded splicing automaton that recognizes languages containing strings embedded with symbols representing splicing rules, and (ii) an automaton that implicitly recognizes the target string. By manipulating these two automata, we extract all rule sequences that lead to the production of the target string (if that string belongs to the splicing language). An algorithm for synthesizing a certain type of target strings based on such rule sequences is presented.

  7. System and method for damping vibration in a drill string

    DOEpatents

    Wassell, Mark Ellsworth; Turner, William Evans; Burgess, Daniel E.; Perry, Carl Allison

    2007-05-22

    A system for damping vibration in a drill string can include a valve assembly having a supply of a fluid, a first member, and a second member capable of moving in relation to first member in response to vibration of the drill bit. The first and second members define a first and a second chamber for holding the fluid. Fluid can flow between the first and second chambers in response to the movement of the second member in relation to the first member. The valve assembly can also include a coil or a valve for varying a resistance of the fluid to flow between the first and second chambers.

  8. System and method for damping vibration in a drill string

    SciTech Connect

    Wassell, Mark Ellsworth; Turner, William Evans; Burgess, Daniel E.; Perry, Carl Allison

    2012-08-14

    A system for damping vibration in a drill string can include a valve assembly having a supply of a fluid, a first member, and a second member capable of moving in relation to first member in response to vibration of the drill bit. The first and second members define a first and a second chamber for holding the fluid. Fluid can flow between the first and second chambers in response to the movement of the second member in relation to the first member. The valve assembly can also include a coil or a valve for varying a resistance of the fluid to flow between the first and second chambers.

  9. System and method for damping vibration in a drill string

    DOEpatents

    Wassell, Mark Ellsworth; Turner, William Evans; Burgess, Daniel E.; Perry, Carl Allison

    2008-05-27

    A system for damping vibration in a drill string can include a valve assembly having a supply of a fluid, a first member, and a second member capable of moving in relation to first member in response to vibration of the drill bit. The first and second members define a first and a second chamber for holding the fluid. Fluid can flow between the first and second chambers in response to the movement of the second member in relation to the first member. The valve assembly can also include a coil or a valve for varying a resistance of the fluid to flow between the first and second chambers.

  10. System and method for damping vibration in a drill string

    DOEpatents

    Wassell, Mark Ellsworth; Turner, William Evans; Burgess, Daniel E; Perry, Carl Allison

    2014-03-04

    A system for damping vibration in a drill string can include a valve assembly having a supply of a fluid, a first member, and a second member capable of moving in relation to first member in response to vibration of the drill bit. The first and second members define a first and a second chamber for holding the fluid. Fluid can flow between the first and second chambers in response to the movement of the second member in relation to the first member. The valve assembly can also include a coil or a valve for varying a resistance of the fluid to flow between the first and second chambers.

  11. System and method for damping vibration in a drill string

    DOEpatents

    Wassell, Mark Ellsworth; Turner, William Evans; Burgess, Daniel E; Perry, Carl Allison

    2015-02-03

    A system for damping vibration in a drill string can include a valve assembly having a supply of a fluid, a first member, and a second member capable of moving in relation to first member in response to vibration of the drill bit. The first and second members define a first and a second chamber for holding the fluid. Fluid can flow between the first and second chambers in response to the movement of the second member in relation to the first member. The valve assembly can also include a coil or a valve for varying a resistance of the fluid to flow between the first and second chambers.

  12. System and method for damping vibration in a drill string

    DOEpatents

    Wassell, Mark Ellsworth; Turner, William Evans; Burgess, Daniel E.; Perry, Carl Allison

    2011-08-16

    A system for damping vibration in a drill string can include a valve assembly having a supply of a fluid, a first member, and a second member capable of moving in relation to first member in response to vibration of the drill bit. The first and second members define a first and a second chamber for holding the fluid. Fluid can flow between the first and second chambers in response to the movement of the second member in relation to the first member. The valve assembly can also include a coil or a valve for varying a resistance of the fluid to flow between the first and second chambers.

  13. ION ACCELERATION SYSTEM

    DOEpatents

    Luce, J.S.; Martin, J.A.

    1960-02-23

    Well focused, intense ion beams are obtained by providing a multi- apertured source grid in front of an ion source chamber and an accelerating multi- apertured grid closely spaced from and in alignment with the source grid. The longest dimensions of the elongated apertures in the grids are normal to the direction of the magnetic field used with the device. Large ion currents may be withdrawn from the source, since they do not pass through any small focal region between the grids.

  14. String mediated phase transitions

    NASA Technical Reports Server (NTRS)

    Copeland, ED; Haws, D.; Rivers, R.; Holbraad, S.

    1988-01-01

    It is demonstrated from first principles how the existence of string-like structures can cause a system to undergo a phase transition. In particular, the role of topologically stable cosmic string in the restoration of spontaneously broken symmetries is emphasized. How the thermodynamic properties of strings alter when stiffness and nearest neighbor string-string interactions are included is discussed.

  15. High acceleration cable deployment system

    NASA Technical Reports Server (NTRS)

    Canning, T. N.; Barns, C. E.; Murphy, J. P.; Gin, B.; King, R. W. (Inventor)

    1981-01-01

    A deployment system that will safely pay one cable from a ballistic forebody when the forebody is separated from an afterbody (to which the cable is secured and when the separation is marked by high acceleration and velocity) is described.

  16. A variable acceleration calibration system

    NASA Astrophysics Data System (ADS)

    Johnson, Thomas H.

    2011-12-01

    A variable acceleration calibration system that applies loads using gravitational and centripetal acceleration serves as an alternative, efficient and cost effective method for calibrating internal wind tunnel force balances. Two proof-of-concept variable acceleration calibration systems are designed, fabricated and tested. The NASA UT-36 force balance served as the test balance for the calibration experiments. The variable acceleration calibration systems are shown to be capable of performing three component calibration experiments with an approximate applied load error on the order of 1% of the full scale calibration loads. Sources of error are indentified using experimental design methods and a propagation of uncertainty analysis. Three types of uncertainty are indentified for the systems and are attributed to prediction error, calibration error and pure error. Angular velocity uncertainty is shown to be the largest indentified source of prediction error. The calibration uncertainties using a production variable acceleration based system are shown to be potentially equivalent to current methods. The production quality system can be realized using lighter materials and a more precise instrumentation. Further research is needed to account for balance deflection, forcing effects due to vibration, and large tare loads. A gyroscope measurement technique is shown to be capable of resolving the balance deflection angle calculation. Long term research objectives include a demonstration of a six degree of freedom calibration, and a large capacity balance calibration.

  17. Termination Proofs for String Rewriting Systems via Inverse Match-Bounds

    NASA Technical Reports Server (NTRS)

    Butler, Ricky (Technical Monitor); Geser, Alfons; Hofbauer, Dieter; Waldmann, Johannes

    2004-01-01

    Annotating a letter by a number, one can record information about its history during a reduction. A string rewriting system is called match-bounded if there is a global upper bound to these numbers. In earlier papers we established match-boundedness as a strong sufficient criterion for both termination and preservation of regular languages. We show now that the string rewriting system whose inverse (left and right hand sides exchanged) is match-bounded, also have exceptional properties, but slightly different ones. Inverse match-bounded systems effectively preserve context-free languages; their sets of normalized strings and their sets of immortal strings are effectively regular. These sets of strings can be used to decide the normalization, the termination and the uniform termination problems of inverse match-bounded systems. We also show that the termination problem is decidable in linear time, and that a certain strong reachability problem is deciable, thus solving two open problems of McNaughton's.

  18. Slim-hole system uses special rig, drill string

    SciTech Connect

    Dupuis, D.; Fanuel, P.

    1993-07-01

    This paper reviews the new Euroslim drilling system which allows deep penetration of small diameter exploration and production wells. The Euroslim approach is an optimized conventional rotary drilling technique that allows continuous coring of the zone of interest. The initial project set the requirements of power transmission and hydraulic optimization to drill 4 3/4 inch holes to 3,500 meters with a single drill pipe size. A second drill string has now been designed to reach 4,000 meters with hole sizes ranging from 3 inches to 3 11/32 inches. This paper reviews the specifications of the drill pipe, core barrels, drill rig, stabilizers, drill bits, and deviation tools. A cost benefit analysis is also provided comparing the slim-bore drilling to conventional drilling.

  19. Resonant acoustic transducer system for a well drilling string

    DOEpatents

    Kent, William H.; Mitchell, Peter G.

    1981-01-01

    For use in transmitting acoustic waves propagated along a well drilling string, a piezoelectric transducer is provided operating in the relatively low loss acoustic propagation range of the well drilling string. The efficiently coupled transmitting transducer incorporates a mass-spring-piezoelectric transmitter combination permitting resonant operation in the desired low frequency range.

  20. Resonant acoustic transducer system for a well drilling string

    DOEpatents

    Nardi, Anthony P.

    1981-01-01

    For use in transmitting acoustic waves propated along a well drilling string, a piezoelectric transducer is provided operating in the relatively low loss acoustic propagation range of the well drilling string. The efficiently coupled transmitting transducer incorporates a mass-spring-piezoelectric transmitter combination permitting a resonant operation in the desired low frequency range.

  1. Cell-balancing currents in parallel strings of a battery system

    NASA Astrophysics Data System (ADS)

    Dubarry, Matthieu; Devie, Arnaud; Liaw, Bor Yann

    2016-07-01

    Lithium-ion batteries are attractive for vehicle electrification or grid modernization applications. In these applications, battery packs are required to have multiple-cell configurations and battery management system to operate properly and safely. Here, a useful equivalent circuit model was developed to simulate the spontaneous transient balancing currents among parallel strings in a battery system. The simulation results were validated with experimental data to illustrate the accuracy and validity of the model predictions. Understanding the transient behavior of such cell and string balancing in a parallel circuit configuration is very important to assess the impacts of current fluctuation and cell variability on a battery system's performance, regarding durability, reliability, safety, abuse tolerance and failure prevention, including possible short circuit or open circuit conditions. Additional features and advantages, including the ability to assessing impacts on the performance of the string assemblies from string swapping or cell/module replacement in the strings, could be realized to aid battery management, maintenance and repair.

  2. Searches for Periodic Neutrino Emission from Binary Systems with 22 and 40 Strings of IceCube

    NASA Technical Reports Server (NTRS)

    Abassi, R.; Abdou, Y.; Abu-Zayyad, T.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Allen, M. M.; Altmann, D.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K.-H.; Benabderrahmane, M. L.; BenZvi, S.; Berdermann, J.; Berghaus, P.

    2011-01-01

    Recent observations of GeV /TeV photon emission from several X-ray binaries have sparked a renewed interest in these objects as galactic particle accelerators. In spite of the available multi-wavelength data, their acceleration mechanisms are not determined, and the nature of the accelerated particles (hadrons or leptons) is unknown. While much evidence favors leptonic emission, it is very likely that a hadronic component is also accelerated in the jets of these binary systems. The observation of neutrino emission would be clear evidence for the presence of a hadronic component in the outflow of these sources. In this paper we look for periodic neutrino emission from binary systems. Such modulation, observed in the photon flux, would be caused by the geometry of these systems. The results of two searches are presented that differ in the treatment of the spectral shape and phase of the emission. The 'generic' search allows parameters to vary freely and best fit values, in a 'model-dependent' search, predictions are used to constrain these parameters. We use the IceCube data taken from May 31, 2007 to April 5, 2008 with its 22-string configuration, and from April 5, 2008 and May 20, 2009 with its 40-string configuration. For the generic search and the 40 string sample, we find that the most significant source in the catalog of 7 binary stars is Cygnus X-3 with a 1.8% probability after trials (2.10" sigma one-sided) of being produced by statistical fluctuations of the background. The model-dependent method tested a range of system geometries - the inclination and the massive star's disk size - for LS I+61 deg 303, no significant excess was found.

  3. On Atwood's Machine with a Nonzero Mass String

    NASA Astrophysics Data System (ADS)

    Tarnopolski, Mariusz

    2015-11-01

    Let us consider a classical high school exercise concerning two weights on a pulley and a string, illustrated in Fig. 1(a). A system like this is called an Atwood's machine and was invented by George Atwood in 1784 as a laboratory experiment to verify the mechanical laws of motion with constant acceleration. Nowadays, Atwood's machine is used for didactic purposes to demonstrate uniformly accelerated motion with acceleration arbitrarily smaller than the gravitational acceleration g. The simplest case is with a massless and frictionless pulley and a massless string. With little effort one can include the mass of the pulley in calculations. The mass of a string has been incorporated previously in some considerations and experiments. These include treatments focusing on friction, justifying the assumption of a massless string, incorporating variations in Earth's gravitational field, comparing the calculated value of g based on a simple experiment, taking the mass of the string into account in such a way that the resulting acceleration is constant, or in one exception solely focusing on a heavy string, but with a slightly different approach. Here we wish to provide i) a derivation of the acceleration and position dependence on the weights' masses based purely on basic dynamical reasoning similar to the conventional version of the exercise, and ii) focus on the influence of the string's linear density, or equivalently its mass, on the outcome compared to a massless string case.

  4. Methods and systems for determining angular orientation of a drill string

    DOEpatents

    Cobern, Martin E.

    2010-03-23

    Preferred methods and systems generate a control input based on a periodically-varying characteristic associated with the rotation of a drill string. The periodically varying characteristic can be correlated with the magnetic tool face and gravity tool face of a rotating component of the drill string, so that the control input can be used to initiate a response in the rotating component as a function of gravity tool face.

  5. A dynamic systems analysis of the ''Rocket-Type'' launching of a well-casing tubing string

    SciTech Connect

    McLauchian, R.A.

    1983-11-01

    A dynamic systems analysis was made of the problem of the ''rocket-type'' launching of a well-casing, tubing string from a well at a hole depth of 3300 feet. The objective of this analysis was to assess whether the observed ''rocket-type'' launching of the tubing string could have been caused by nozzle-breakthrough or tubing failure at the SRC No. 1 in Eddy County, New Mexico. The analysis considers tubing weight, fluid buoyancy, external fluid drag and fluid thrust forces on the tubing string. The tubing string and the fluid columns in the moving string and the annular region external to the tubing string are considered as a coupled dynamic system. Several situations of interest are considered relevant to the dynamic behavior of and hence implied failure mode for the tubing string. Summary plots show typical dynamic behavior as a function of internal shut-in pressure and tubing nozzle diameter.

  6. String resistance detector

    NASA Technical Reports Server (NTRS)

    Hall, A. Daniel (Inventor); Davies, Francis J. (Inventor)

    2007-01-01

    Method and system are disclosed for determining individual string resistance in a network of strings when the current through a parallel connected string is unknown and when the voltage across a series connected string is unknown. The method/system of the invention involves connecting one or more frequency-varying impedance components with known electrical characteristics to each string and applying a frequency-varying input signal to the network of strings. The frequency-varying impedance components may be one or more capacitors, inductors, or both, and are selected so that each string is uniquely identifiable in the output signal resulting from the frequency-varying input signal. Numerical methods, such as non-linear regression, may then be used to resolve the resistance associated with each string.

  7. Implementation of Karp-Rabin string matching algorithm in reconfigurable hardware for network intrusion prevention system

    NASA Astrophysics Data System (ADS)

    Botwicz, Jakub; Buciak, Piotr; Sapiecha, Piotr

    2006-03-01

    Intrusion Prevention Systems (IPSs) have become widely recognized as a powerful tool and an important element of IT security safeguards. The essential feature of network IPSs is searching through network packets and matching multiple strings, that are fingerprints of known attacks. String matching is highly resource consuming and also the most significant bottleneck of IPSs. In this article an extension of the classical Karp-Rabin algorithm and its implementation architectures were examined. The result is a software, which generates a source code of a string matching module in hardware description language, that could be easily used to create an Intrusion Prevention System implemented in reconfigurable hardware. The prepared module matches the complete set of Snort IPS signatures achieving throughput of over 2 Gbps on an Altera Stratix I1 evaluation board. The most significant advantage of the proposed architecture is that the update of the patterns database does not require reconfiguration of the circuitry.

  8. Cosmic strings with curvature corrections

    NASA Astrophysics Data System (ADS)

    Boisseau, Bruno; Letelier, Patricio S.

    1992-08-01

    A generic model of string described by a Lagrangian density that depends on the extrinsic curvature of the string worldsheet is studied. Using a system of coordinates adapted to the string world sheet the equation of motion and the energy-momentum tensor are derived for strings evolving in curved spacetime. We find that the curvature corrections may change the relation between the string energy density and the tension. It can also introduce heat propagation along the string. We also find for the Polyakov as well as Nambu strings with a topological term that the open string end points can travel with a speed less than the velocity of light.

  9. RHIC sextant test: Accelerator systems and performance

    SciTech Connect

    Pilat, F.; Trbojevic, D.; Ahrens, L.

    1997-08-01

    One sextant of the RHIC Collider was commissioned in early 1997 with beam. We describe here the performance of the accelerator systems, instrumentation subsystems and application software. We also describe a ramping test without beam that took place after the commissioning with beam. Finally, we analyze the implications of accelerator systems performance and their impact on the planning for RHIC installation and commissioning.

  10. The Spallation Neutron Source accelerator system design

    NASA Astrophysics Data System (ADS)

    Henderson, S.; Abraham, W.; Aleksandrov, A.; Allen, C.; Alonso, J.; Anderson, D.; Arenius, D.; Arthur, T.; Assadi, S.; Ayers, J.; Bach, P.; Badea, V.; Battle, R.; Beebe-Wang, J.; Bergmann, B.; Bernardin, J.; Bhatia, T.; Billen, J.; Birke, T.; Bjorklund, E.; Blaskiewicz, M.; Blind, B.; Blokland, W.; Bookwalter, V.; Borovina, D.; Bowling, S.; Bradley, J.; Brantley, C.; Brennan, J.; Brodowski, J.; Brown, S.; Brown, R.; Bruce, D.; Bultman, N.; Cameron, P.; Campisi, I.; Casagrande, F.; Catalan-Lasheras, N.; Champion, M.; Champion, M.; Chen, Z.; Cheng, D.; Cho, Y.; Christensen, K.; Chu, C.; Cleaves, J.; Connolly, R.; Cote, T.; Cousineau, S.; Crandall, K.; Creel, J.; Crofford, M.; Cull, P.; Cutler, R.; Dabney, R.; Dalesio, L.; Daly, E.; Damm, R.; Danilov, V.; Davino, D.; Davis, K.; Dawson, C.; Day, L.; Deibele, C.; Delayen, J.; DeLong, J.; Demello, A.; DeVan, W.; Digennaro, R.; Dixon, K.; Dodson, G.; Doleans, M.; Doolittle, L.; Doss, J.; Drury, M.; Elliot, T.; Ellis, S.; Error, J.; Fazekas, J.; Fedotov, A.; Feng, P.; Fischer, J.; Fox, W.; Fuja, R.; Funk, W.; Galambos, J.; Ganni, V.; Garnett, R.; Geng, X.; Gentzlinger, R.; Giannella, M.; Gibson, P.; Gillis, R.; Gioia, J.; Gordon, J.; Gough, R.; Greer, J.; Gregory, W.; Gribble, R.; Grice, W.; Gurd, D.; Gurd, P.; Guthrie, A.; Hahn, H.; Hardek, T.; Hardekopf, R.; Harrison, J.; Hatfield, D.; He, P.; Hechler, M.; Heistermann, F.; Helus, S.; Hiatt, T.; Hicks, S.; Hill, J.; Hill, J.; Hoff, L.; Hoff, M.; Hogan, J.; Holding, M.; Holik, P.; Holmes, J.; Holtkamp, N.; Hovater, C.; Howell, M.; Hseuh, H.; Huhn, A.; Hunter, T.; Ilg, T.; Jackson, J.; Jain, A.; Jason, A.; Jeon, D.; Johnson, G.; Jones, A.; Joseph, S.; Justice, A.; Kang, Y.; Kasemir, K.; Keller, R.; Kersevan, R.; Kerstiens, D.; Kesselman, M.; Kim, S.; Kneisel, P.; Kravchuk, L.; Kuneli, T.; Kurennoy, S.; Kustom, R.; Kwon, S.; Ladd, P.; Lambiase, R.; Lee, Y. Y.; Leitner, M.; Leung, K.-N.; Lewis, S.; Liaw, C.; Lionberger, C.; Lo, C. C.; Long, C.; Ludewig, H.; Ludvig, J.; Luft, P.; Lynch, M.; Ma, H.; MacGill, R.; Macha, K.; Madre, B.; Mahler, G.; Mahoney, K.; Maines, J.; Mammosser, J.; Mann, T.; Marneris, I.; Marroquin, P.; Martineau, R.; Matsumoto, K.; McCarthy, M.; McChesney, C.; McGahern, W.; McGehee, P.; Meng, W.; Merz, B.; Meyer, R.; Meyer, R.; Miller, B.; Mitchell, R.; Mize, J.; Monroy, M.; Munro, J.; Murdoch, G.; Musson, J.; Nath, S.; Nelson, R.; Nelson, R.; O`Hara, J.; Olsen, D.; Oren, W.; Oshatz, D.; Owens, T.; Pai, C.; Papaphilippou, I.; Patterson, N.; Patterson, J.; Pearson, C.; Pelaia, T.; Pieck, M.; Piller, C.; Plawski, T.; Plum, M.; Pogge, J.; Power, J.; Powers, T.; Preble, J.; Prokop, M.; Pruyn, J.; Purcell, D.; Rank, J.; Raparia, D.; Ratti, A.; Reass, W.; Reece, K.; Rees, D.; Regan, A.; Regis, M.; Reijonen, J.; Rej, D.; Richards, D.; Richied, D.; Rode, C.; Rodriguez, W.; Rodriguez, M.; Rohlev, A.; Rose, C.; Roseberry, T.; Rowton, L.; Roybal, W.; Rust, K.; Salazer, G.; Sandberg, J.; Saunders, J.; Schenkel, T.; Schneider, W.; Schrage, D.; Schubert, J.; Severino, F.; Shafer, R.; Shea, T.; Shishlo, A.; Shoaee, H.; Sibley, C.; Sims, J.; Smee, S.; Smith, J.; Smith, K.; Spitz, R.; Staples, J.; Stein, P.; Stettler, M.; Stirbet, M.; Stockli, M.; Stone, W.; Stout, D.; Stovall, J.; Strelo, W.; Strong, H.; Sundelin, R.; Syversrud, D.; Szajbler, M.; Takeda, H.; Tallerico, P.; Tang, J.; Tanke, E.; Tepikian, S.; Thomae, R.; Thompson, D.; Thomson, D.; Thuot, M.; Treml, C.; Tsoupas, N.; Tuozzolo, J.; Tuzel, W.; Vassioutchenko, A.; Virostek, S.; Wallig, J.; Wanderer, P.; Wang, Y.; Wang, J. G.; Wangler, T.; Warren, D.; Wei, J.; Weiss, D.; Welton, R.; Weng, J.; Weng, W.-T.; Wezensky, M.; White, M.; Whitlatch, T.; Williams, D.; Williams, E.; Wilson, K.; Wiseman, M.; Wood, R.; Wright, P.; Wu, A.; Ybarrolaza, N.; Young, K.; Young, L.; Yourd, R.; Zachoszcz, A.; Zaltsman, A.; Zhang, S.; Zhang, W.; Zhang, Y.; Zhukov, A.

    2014-11-01

    The Spallation Neutron Source (SNS) was designed and constructed by a collaboration of six U.S. Department of Energy national laboratories. The SNS accelerator system consists of a 1 GeV linear accelerator and an accumulator ring providing 1.4 MW of proton beam power in microsecond-long beam pulses to a liquid mercury target for neutron production. The accelerator complex consists of a front-end negative hydrogen-ion injector system, an 87 MeV drift tube linear accelerator, a 186 MeV side-coupled linear accelerator, a 1 GeV superconducting linear accelerator, a 248-m circumference accumulator ring and associated beam transport lines. The accelerator complex is supported by ~100 high-power RF power systems, a 2 K cryogenic plant, ~400 DC and pulsed power supply systems, ~400 beam diagnostic devices and a distributed control system handling ~100,000 I/O signals. The beam dynamics design of the SNS accelerator is presented, as is the engineering design of the major accelerator subsystems.

  11. String test

    MedlinePlus

    Duodenal parasites test; Giardia - string test ... To have this test, you swallow a string with a weighted gelatin capsule on the end. The string is pulled out 4 hours later. Any bile , blood, or mucus attached to ...

  12. Radiation Safety Systems for Accelerator Facilities

    SciTech Connect

    James C. Liu; Jeffrey S. Bull; John Drozdoff; Robert May; Vaclav Vylet

    2001-10-01

    The Radiation Safety System (RSS) of an accelerator facility is used to protect people from prompt radiation hazards associated with accelerator operation. The RSS is a fully interlocked, engineered system with a combination of passive and active elements that are reliable, redundant, and fail-safe. The RSS consists of the Access Control System (ACS) and the Radiation Containment System (RCS). The ACS is to keep people away from the dangerous radiation inside the shielding enclosure. The RCS limits and contains the beam/radiation conditions to protect people from the prompt radiation hazards outside the shielding enclosure in both normal and abnormal operations. The complexity of a RSS depends on the accelerator and its operation, as well as associated hazard conditions. The approaches of RSS among different facilities can be different. This report gives a review of the RSS for accelerator facilities.

  13. High efficiency ion beam accelerator system

    NASA Technical Reports Server (NTRS)

    Aston, G.

    1981-01-01

    An ion accelerator system that successfully combines geometrical and electrostatic focusing principles is presented. This accelerator system uses thin, concave, multiple-hole, closely spaced graphite screen and focusing grids which are coupled to single slot accelerator and decelerator grids to provide high ion extraction efficiency and good focusing. Tests with the system showed a substantial improvement in ion beam current density and collimation as compared with a Pierce electrode configuration. Durability of the thin graphite screen and focusing grids has been proven, and tests are being performed to determine the minimum screen and focusing grid spacing and thickness required to extract the maximum reliable beam current density. Compared with present neutral beam injector accelerator systems, this one has more efficient ion extraction, easier grid alignment, easier fabrication, a less cumbersome design, and the capacity to be constructed in a modular fashion. Conceptual neutral beam injector designs using this modular approach have electrostatic beam deflection plates downstream of each module.

  14. Advanced Microgravity Acceleration Measurement Systems Being Developed

    NASA Technical Reports Server (NTRS)

    Sicker, Ronald J.; Kacpura, Thomas J.

    2002-01-01

    The Advanced Microgravity Acceleration Measurement Systems (AMAMS) project at the NASA Glenn Research Center is part of the Instrument Technology Development program to develop advanced sensor systems. The primary focus of the AMAMS project is to develop microelectromechanical (MEMS) acceleration sensor systems to replace existing electromechanical-sensor-based systems presently used to assess relative gravity levels aboard spacecraft. These systems are used in characterizing both vehicle and payload responses to low-gravity vibroacoustic environments. The collection of microgravity acceleration data has cross-disciplinary utility to the microgravity life and physical sciences and the structural dynamics communities. The inherent advantages of semiconductor-based systems are reduced size, mass, and power consumption, while providing enhanced stability.

  15. Vehicle Systems Integration Laboratory Accelerates Powertrain Development

    ScienceCinema

    None

    2016-07-12

    ORNL's Vehicle Systems Integration (VSI) Laboratory accelerates the pace of powertrain development by performing prototype research and characterization of advanced systems and hardware components. The VSI Lab is capable of accommodating a range of platforms from advanced light-duty vehicles to hybridized Class 8 powertrains with the goals of improving overall system efficiency and reducing emissions.

  16. Vehicle Systems Integration Laboratory Accelerates Powertrain Development

    SciTech Connect

    2014-04-15

    ORNL's Vehicle Systems Integration (VSI) Laboratory accelerates the pace of powertrain development by performing prototype research and characterization of advanced systems and hardware components. The VSI Lab is capable of accommodating a range of platforms from advanced light-duty vehicles to hybridized Class 8 powertrains with the goals of improving overall system efficiency and reducing emissions.

  17. HRIBF Tandem Accelerator Radiation Safety System Upgrade

    NASA Astrophysics Data System (ADS)

    Juras, R. C.; Blankenship, J. L.

    1999-06-01

    The HRIBF Tandem Accelerator Radiation Safety System was designed to permit experimenters and operations staff controlled access to beam transport and experiment areas with accelerated beam present. Neutron-Gamma detectors are mounted in each area at points of maximum dose rate and the resulting signals are integrated by redundant circuitry; beam is stopped if dose rate or integrated dose exceeds established limits. This paper will describe the system, in use for several years at the HRIBF, and discuss changes recently made to modernize the system and to make the system compliant with DOE Order 5480.25 and related ORNL updated safety rules.

  18. Application accelerator system having bunch control

    DOEpatents

    Wang, Dunxiong; Krafft, Geoffrey Arthur

    1999-01-01

    An application accelerator system for monitoring the gain of a free electron laser. Coherent Synchrotron Radiation (CSR) detection techniques are used with a bunch length monitor for ultra short, picosec to several tens of femtosec, electron bunches. The monitor employs an application accelerator, a coherent radiation production device, an optical or beam chopping device, an infrared radiation collection device, a narrow-banding filter, an infrared detection device, and a control.

  19. Application accelerator system having bunch control

    DOEpatents

    Wang, D.; Krafft, G.A.

    1999-06-22

    An application accelerator system for monitoring the gain of a free electron laser is disclosed. Coherent Synchrotron Radiation (CSR) detection techniques are used with a bunch length monitor for ultra short, picosec to several tens of femtosec, electron bunches. The monitor employs an application accelerator, a coherent radiation production device, an optical or beam chopping device, an infrared radiation collection device, a narrow-banding filter, an infrared detection device, and a control. 1 fig.

  20. Space Acceleration Measurement System-II

    NASA Technical Reports Server (NTRS)

    Foster, William

    2009-01-01

    Space Acceleration Measurement System (SAMS-II) is an ongoing study of the small forces (vibrations and accelerations) on the ISS that result from the operation of hardware, crew activities, as well as dockings and maneuvering. Results will be used to generalize the types of vibrations affecting vibration-sensitive experiments. Investigators seek to better understand the vibration environment on the space station to enable future research.

  1. The EMMA Accelerator, a Diagnostic Systems Overview

    SciTech Connect

    Kalinin, A.; Berg, J.; Bliss, N. Cox, G.; Dufau, M.; Gallagher, A.; Hill, C.; Jones, J.; Ma, L.; McIntosh, P.; Muratori, B.; Oates, A.; Shepherd B.; Smith, R.; Hock, K.; Holder, D.; Ibison, M., Kirkman I.; Borrell, R.; Crisp, J.; Fellenz, B.; Wendt, M.

    2011-09-04

    The 'EMMA' Non-Scaling Fixed Field Alternating Gradient (ns-FFAG) international project is currently being commissioned at Daresbury Laboratory, UK. This accelerator has been equipped with a number of diagnostic systems to facilitate this. These systems include a novel time-domain-multiplexing BPM system, moveable screen systems, a time-of-flight instrument, Faraday cups, and injection/extraction tomography sections to analyze the single bunch beams. An upgrade still to implement includes the installation of wall current monitors. This paper gives an overview of these systems and shows some data and results from the diagnostics that have contributed to the successful demonstration of a serpentine acceleration by this novel accelerator.

  2. RHIC Sextant Test - Accelerator Systems and Performance

    NASA Astrophysics Data System (ADS)

    Pilat, F.; Ahrens, L.; Brown, K.; Connolly, R.; dell, G. F.; Fischer, W.; Kewisch, J.; Mackay, W.; Mane, V.; Peggs, S.; Satogata, T.; Tepikian, S.; Thompson, P.; Trbojevic, D.; Tsoupas, N.; Wei, J.

    1997-05-01

    One sextant of the RHIC collider and the full AtR (AGS to RHIC) transfer line have been commissioned in early 1997 with beam. We describe here the design and performance of the accelerator systems during the test, such as the magnet and power supply systems, instrumentation subsystems and application software. After reviewing the main milestones of the commissioning we describe a ramping test without beam that took place after the commissioning with beam. Finally, we analyze the implications of accelerator systems preformance and their impact on the plannig for RHIC installation and commissioning.

  3. Generic device controller for accelerator control systems

    SciTech Connect

    Mariotti, R.; Buxton, W.; Frankel, R.; Hoff, L.

    1987-01-01

    A new distributed intelligence control system has become operational at the AGS for transport, injection, and acceleration of heavy ions. A brief description of the functionality of the physical devices making up the system is given. An attempt has been made to integrate the devices for accelerator specific interfacing into a standard microprocessor system, namely, the Universal Device Controller (UDC). The main goals for such a generic device controller are to provide: local computing power; flexibility to configure; and real time event handling. The UDC assemblies and software are described. (LEW)

  4. A paper form processing system with an error correcting function for reading handwritten Kanji strings

    SciTech Connect

    Katsumi Marukawa; Kazuki Nakashima; Masashi Koga; Yoshihiro Shima; Hiromichi Fujisawa

    1994-12-31

    This paper presents a paper form processing system with an error correcting function for reading handwritten kanji strings. In the paper form processing system, names and addresses are important key data, and especially this paper takes up an error correcting method for name and address recognition. The method automatically corrects errors of the kanji OCR (Optical Character Reader) with the help of word dictionaries and other knowledge. Moreover, it allows names and addresses to be written in any style. The method consists of word matching {open_quotes}furigana{close_quotes} verification for name strings, and address approval for address strings. For word matching, kanji name candidates are extracted by automaton-type word matching. In {open_quotes}furigana{close_quotes} verification, kana candidate characters recognized by the kana OCR are compared with kana`s searched from the name dictionary based on kanji name candidates, given by the word matching. The correct name is selected from the results of word matching and furigana verification. Also, the address approval efficiently searches for the right address based on a bottom-up procedure which follows hierarchical relations from a lower placename to a upper one by using the positional condition among the placenames. We ascertained that the error correcting method substantially improves the recognition rate and processing speed in experiments on 5,032 forms.

  5. The BNL Accelerator Test Facility control system

    SciTech Connect

    Malone, R.; Bottke, I.; Fernow, R.; Ben-Zvi, I.

    1993-01-01

    Described is the VAX/CAMAC-based control system for Brookhaven National Laboratory's Accelerator Test Facility, a laser/linac research complex. Details of hardware and software configurations are presented along with experiences of using Vsystem, a commercial control system package.

  6. Argonne Tandem-Linac Accelerator System

    SciTech Connect

    Bollinger, L.M.

    1983-01-01

    Design considerations and operational experience for the existing heavy-ion accelerator consisting of a tandem injecting into a superconducting linac are summarized, with emphasis on the general features of the system. This introduction provides the basis for a discussion of the objectives and design of ATLAS, a larger tandem-linac system being formed by expanding the existing superconducting linac.

  7. Ground test accelerator control system software

    SciTech Connect

    Burczyk, L.; Dalesio, R.; Dingler, R.; Hill, J.; Howell, J.A.; Kerstiens, D.; King, R.; Kozubal, A.; Little, C.; Martz, V.; Rothrock, R.; Sutton, J.

    1988-01-01

    The GTA control system provides an environment in which the automation of a state-of-the-art accelerator can be developed. It makes use of commercially available computers, workstations, computer networks, industrial I/O equipment, and software. This system has built-in supervisory control (like most accelerator control systems), tools to support continuous control (like the process control industry), and sequential control for automatic startup and fault recovery (like few other accelerator control systems). Several software tools support these levels of control: a real-time operating system (VxWorks) with a real-time kernel (VRTX), a configuration database, a sequencer, and a graphics editor. VxWorks supports multitasking, fast context-switching, and preemptive scheduling. VxWorks/VRTX is a network-based development environment specifically designed to work in partnership with the UNIX operating system. A database provides the interface to the accelerator components. It consists of a run time library and a database configuration and editing tool. A sequencer initiates and controls the operation of all sequence programs (expressed as state programs). A graphics editor gives the user the ability to create color graphic displays showing the state of the machine in either text or graphics form. 11 refs., 2 figs.

  8. Quintet pairing and non-Abelian vortex string in spin- 3/2 cold atomic systems

    SciTech Connect

    Wu, C.

    2010-03-02

    We study the s-wave quintet Cooper pairing phase (S{sub pair} = 2) in spin-3/2 cold atomic systems and identify various novel features which do not appear in spin-1/2 pairing systems. A single quantum vortex is shown to be energetically less stable than a pair of half-quantum vortices. The half-quantum vortex exhibits the global analogue of the non-Abelian Alice string and SO(4) Cheshire charge in gauge theories. The non-Abelian half-quantum vortex loop enables topological generation of quantum entanglement.

  9. Optical analysis and thermal management of 2-cell strings linear concentrating photovoltaic system

    NASA Astrophysics Data System (ADS)

    Reddy, K. S.; Kamnapure, Nikhilesh R.

    2015-09-01

    This paper presents the optical and thermal analyses for a linear concentrating photovoltaic/thermal collector under different operating conditions. Linear concentrating photovoltaic system (CPV) consists of a highly reflective mirror, a receiver and semi-dual axis tracking mechanism. The CPV receiver embodies two strings of triple-junction cells (100 cells in each string) adhered to a mild steel circular tube mounted at the focal length of trough. This system provides 560 W of electricity and 1580 W of heat which needs to be dissipated by active cooling. The Al2O3/Water nanofluid is used as heat transfer fluid (HTF) flowing through circular receiver for CPV cells cooling. Optical analysis of linear CPV system with 3.35 m2 aperture and geometric concentration ratio (CR) of 35 is carried out using Advanced System Analysis Program (ASAP) an optical simulation tool. Non-uniform intensity distribution model of solar disk is used to model the sun in ASAP. The impact of random errors including slope error (σslope), tracking error (σtrack) and apparent change in sun's width (σsun) on optical performance of collector is shown. The result from the optical simulations shows the optical efficiency (ηo) of 88.32% for 2-cell string CPV concentrator. Thermal analysis of CPV receiver is carried out with conjugate heat transfer modeling in ANSYS FLUENT-14. Numerical simulations of Al2O3/Water nanofluid turbulent forced convection are performed for various parameters such as nanoparticle volume fraction (φ), Reynolds number (Re). The addition of the nanoparticle in water enhances the heat transfer in the ranges of 3.28% - 35.6% for φ = 1% - 6%. Numerical results are compared with literature data which shows the reasonable agreement.

  10. Acceleration by pulsar winds in binary systems

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.; Gaisser, T. K.

    1990-01-01

    In the absence of accretion torques, a pulsar in a binary system will spin down due to electromagnetic dipole radiation and the spin-down power will drive a wind of relativistic electron-positron pairs. Winds from pulsars with short periods will prevent any subsequent accretion but may be confined by the companion star atmosphere, wind, or magnetosphere to form a standing shock. The authors investigate the possibility of particle acceleration at such a pulsar wind shock and the production of very high energy (VHE) and ultra high energy (UHE) gamma rays from interactions of accelerated protons in the companion star's wind or atmosphere. They find that in close binaries containing active pulsars, protons will be shock accelerated to a maximum energy dependent on the pulsar spin-down luminosity. If a significant fraction of the spin-down power goes into particle acceleration, these systems should be sources of VHE and possibly UHE gamma rays. The authors discuss the application of the pulsar wind model to binary sources such as Cygnus X-3, as well as the possibility of observing VHE gamma-rays from known binary radio pulsar systems.

  11. String Things.

    ERIC Educational Resources Information Center

    Mesa Public Schools, AZ.

    Designed for music educators instructing grades 4 through 8 in string instruments, this Mesa (Arizona) public schools guide presents information on the string curriculum, orchestras, and practicing. The goals and objectives for string instruments delineate grade levels and how student skills will be verified. Following 17 curriculum goal tests,…

  12. Hammered Strings

    NASA Astrophysics Data System (ADS)

    Rossing, Thomas D.

    In the next three chapters we consider the science of hammered string instruments. In this chapter, we present a brief discussion of vibrating strings excited by a hard or soft hammer. Chapter 20 discusses the most important hammered string instrument, the piano - probably the most versatile and popular of all musical instruments. Chapter 21 discusses hammered dulcimers, especially the American folk dulcimer.

  13. BNL ACCELERATOR TEST FACILITY CONTROL SYSTEM UPGRADE.

    SciTech Connect

    MALONE,R.; BEN-ZVI,I.; WANG,X.; YAKIMENKO,V.

    2001-06-18

    Brookhaven National Laboratory's Accelerator Test Facility (ATF) has embarked on a complete upgrade of its decade old computer system. The planned improvements affect every major component: processors (Intel Pentium replaces VAXes), operating system (Linux/Real-Time Linux supplants OpenVMS), and data acquisition equipment (fast Ethernet equipment replaces CAMAC serial highway.) This paper summarizes the strategies and progress of the upgrade along with plans for future expansion.

  14. Induction accelerators for the phase rotator system

    SciTech Connect

    Reginato, Lou; Yu, Simon; Vanecek, Dave

    2001-07-30

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

  15. Nonquantized dirac monopoles and strings in the berry phase of anisotropic spin systems.

    PubMed

    Bruno, Patrick

    2004-12-10

    The Berry phase of an anisotropic spin system that is adiabatically rotated along a closed circuit C is investigated. It is shown that the Berry phase consists of two contributions: (i) a geometric contribution which can be interpreted as the flux through C of a nonquantized Dirac monopole, and (ii) a topological contribution which can be interpreted as the flux through C of a Dirac string carrying a nonquantized flux, i.e., a spin analogue of the Aharonov-Bohm effect. Various experimental consequences of this novel effect are discussed. PMID:15697856

  16. Accelerating Science Driven System Design With RAMP

    SciTech Connect

    Wawrzynek, John

    2015-05-01

    Researchers from UC Berkeley, in collaboration with the Lawrence Berkeley National Lab, are engaged in developing an Infrastructure for Synthesis with Integrated Simulation (ISIS). The ISIS Project was a cooperative effort for “application-driven hardware design” that engages application scientists in the early parts of the hardware design process for future generation supercomputing systems. This project served to foster development of computing systems that are better tuned to the application requirements of demanding scientific applications and result in more cost-effective and efficient HPC system designs. In order to overcome long conventional design-cycle times, we leveraged reconfigurable devices to aid in the design of high-efficiency systems, including conventional multi- and many-core systems. The resulting system emulation/prototyping environment, in conjunction with the appropriate intermediate abstractions, provided both a convenient user programming experience and retained flexibility, and thus efficiency, of a reconfigurable platform. We initially targeted the Berkeley RAMP system (Research Accelerator for Multiple Processors) as that hardware emulation environment to facilitate and ultimately accelerate the iterative process of science-driven system design. Our goal was to develop and demonstrate a design methodology for domain-optimized computer system architectures. The tangible outcome is a methodology and tools for rapid prototyping and design-space exploration, leading to highly optimized and efficient HPC systems.

  17. Fermilab tevatron high level RF accelerating systems

    SciTech Connect

    Kerns, Q.; Kerns, C.; Miller, H.; Reid, J.; Tawzer, S.; Webber, R.; Wildman, D.

    1985-10-01

    Eight tuned rf cavities have been installed and operated in the F0 straight section of the Tevatron. Their mechanical placement along the beam line enables them to be operated for colliding beams as two independent groups of four cavities, group 1-4 accelerating antiprotons and group 5-8 accelerating protons. The only difference is that the spacing between cavities 4 and 5 was increased to stay clear of the F0 colliding point. The cavities can easily be rephased by switching cables in a low-level distribution system (fan-out) so that the full accelerating capability of all eight cavities can be used during fixed target operations. Likewise, the cables from capacitive probes on each cavity gap can be switched to proper lengths and summed in a fan-back system to give an rf signal representing the amplitude and phase as ''seen by the beam,'' separately for protons and antiprotons. Such signals have been used to phase lock the Tevatron to the Main Ring for synchronous transfer. A cavity consists of two quarter-wave resonators placed back to back with a coaxial drift tube separating the two accelerating gaps by ..pi.. radians. The cavities are very similar to the prototype which has been previously described/sup 3/ and is operating as Station 8 in the Tevatron. Only additional water cooling around the high current region of the drift tube supports and a double loop used to monitor the unbalance current through the Hipernom mode damping resistor have been added. Each cavity has a Q of about7100, a shunt impedance of 1.2 M..cap omega.., and is capable of running cw with a peak accelerating voltage of 360

  18. Application of local area networks to accelerator control systems at the Stanford Linear Accelerator

    SciTech Connect

    Fox, J.D.; Linstadt, E.; Melen, R.

    1983-03-01

    The history and current status of SLAC's SDLC networks for distributed accelerator control systems are discussed. These local area networks have been used for instrumentation and control of the linear accelerator. Network topologies, protocols, physical links, and logical interconnections are discussed for specific applications in distributed data acquisition and control system, computer networks and accelerator operations.

  19. Pulsed power systems for the DARHT accelerators

    SciTech Connect

    Downing, J.N.; Parsons, W.M.; Earley, L.M.; Melton, J.G.; Moir, D.C.; Carlson, R.L.; Barnes, G.A.; Builta, L.A.; Eversole, S.A.; Keel, G.I.; Rader, D.C.; Romero, J.A.; Shurter, R.P.

    1991-01-01

    The Dual-Axis Radiographic Hydro Test (DARHT) Facility is being designed to produce high-resolution flash radiographs of hydrodynamics experiments. Two 16- to 20-MeV linear induction accelerators (LIA), with an included angle of 90{degree}, are used to produce intense bremsstrahlung x-ray pulses of short duration (60-ns flat-top). Each accelerator has a 4-MeV electron source that injects an electron beam into a series of 250-kV induction cells. The three major pulsed-power systems are the injectors, the induction-cell pulsed-power (ICPP) units, and the ICPP trigger systems, and are discussed in this paper. 11 refs., 5 figs, 3 tabs.

  20. Integration Test of the High Voltage Hall Accelerator System Components

    NASA Technical Reports Server (NTRS)

    Kamhawi, Hani; Haag, Thomas; Huang, Wensheng; Pinero, Luis; Peterson, Todd; Dankanich, John

    2013-01-01

    NASA Glenn Research Center is developing a 4 kilowatt-class Hall propulsion system for implementation in NASA science missions. NASA science mission performance analysis was completed using the latest high voltage Hall accelerator (HiVHAc) and Aerojet-Rocketdyne's state-of-the-art BPT-4000 Hall thruster performance curves. Mission analysis results indicated that the HiVHAc thruster out performs the BPT-4000 thruster for all but one of the missions studied. Tests of the HiVHAc system major components were performed. Performance evaluation of the HiVHAc thruster at NASA Glenn's vacuum facility 5 indicated that thruster performance was lower than performance levels attained during tests in vacuum facility 12 due to the lower background pressures attained during vacuum facility 5 tests when compared to vacuum facility 12. Voltage-Current characterization of the HiVHAc thruster in vacuum facility 5 showed that the HiVHAc thruster can operate stably for a wide range of anode flow rates for discharge voltages between 250 and 600 volts. A Colorado Power Electronics enhanced brassboard power processing unit was tested in vacuum for 1,500 hours and the unit demonstrated discharge module efficiency of 96.3% at 3.9 kilowatts and 650 volts. Stand-alone open and closed loop tests of a VACCO TRL 6 xenon flow control module were also performed. An integrated test of the HiVHAc thruster, brassboard power processing unit, and xenon flow control module was performed and confirmed that integrated operation of the HiVHAc system major components. Future plans include continuing the maturation of the HiVHAc system major components and the performance of a single-string integration test.

  1. Fermilab Tevatron high level rf accelerating systems

    SciTech Connect

    Kerns, Q.; Kerns, C.; Miller, H.; Tawser, S.; Reid, J.; Webber, R.; Wildman, D.

    1985-06-01

    Eight tuned rf cavities have been installed and operated in the F0 straight section of the Tevatron. Their mechanical placement along the beam line enables them to be operated for colliding beams as two independent groups of four cavities, group 1-4 accelerating antiprotons and group 5-8 accelerating protons. The only difference is that the spacing between cavities 4 and 5 was increased to stay clear of the F0 colliding point. The cavities can easily be rephased by switching cables in a low-level distribution system (fan-out) so that the full accelerating capability of all eight cavities can be used during fixed target operations. Likewise, the cables from capacitive probes on each cavity gap can be switched to proper lengths and summed in a fan-back system to give an rf signal representing the amplitude and phase as ''seen by the beam,'' separately for protons and antiprotons. Such signals have been used to phase lock the Tevatron to the Main Ring for synchronous transfer.

  2. Open Hardware for CERN's accelerator control systems

    NASA Astrophysics Data System (ADS)

    van der Bij, E.; Serrano, J.; Wlostowski, T.; Cattin, M.; Gousiou, E.; Alvarez Sanchez, P.; Boccardi, A.; Voumard, N.; Penacoba, G.

    2012-01-01

    The accelerator control systems at CERN will be upgraded and many electronics modules such as analog and digital I/O, level converters and repeaters, serial links and timing modules are being redesigned. The new developments are based on the FPGA Mezzanine Card, PCI Express and VME64x standards while the Wishbone specification is used as a system on a chip bus. To attract partners, the projects are developed in an `Open' fashion. Within this Open Hardware project new ways of working with industry are being evaluated and it has been proven that industry can be involved at all stages, from design to production and support.

  3. Variable Acceleration Force Calibration System (VACS)

    NASA Technical Reports Server (NTRS)

    Rhew, Ray D.; Parker, Peter A.; Johnson, Thomas H.; Landman, Drew

    2014-01-01

    Conventionally, force balances have been calibrated manually, using a complex system of free hanging precision weights, bell cranks, and/or other mechanical components. Conventional methods may provide sufficient accuracy in some instances, but are often quite complex and labor-intensive, requiring three to four man-weeks to complete each full calibration. To ensure accuracy, gravity-based loading is typically utilized. However, this often causes difficulty when applying loads in three simultaneous, orthogonal axes. A complex system of levers, cranks, and cables must be used, introducing increased sources of systematic error, and significantly increasing the time and labor intensity required to complete the calibration. One aspect of the VACS is a method wherein the mass utilized for calibration is held constant, and the acceleration is changed to thereby generate relatively large forces with relatively small test masses. Multiple forces can be applied to a force balance without changing the test mass, and dynamic forces can be applied by rotation or oscillating acceleration. If rotational motion is utilized, a mass is rigidly attached to a force balance, and the mass is exposed to a rotational field. A large force can be applied by utilizing a large rotational velocity. A centrifuge or rotating table can be used to create the rotational field, and fixtures can be utilized to position the force balance. The acceleration may also be linear. For example, a table that moves linearly and accelerates in a sinusoidal manner may also be utilized. The test mass does not have to move in a path that is parallel to the ground, and no re-leveling is therefore required. Balance deflection corrections may be applied passively by monitoring the orientation of the force balance with a three-axis accelerometer package. Deflections are measured during each test run, and adjustments with respect to the true applied load can be made during the post-processing stage. This paper will

  4. Multi-pattern string matching algorithms comparison for intrusion detection system

    NASA Astrophysics Data System (ADS)

    Hasan, Awsan A.; Rashid, Nur'Aini Abdul; Abdulrazzaq, Atheer A.

    2014-12-01

    Computer networks are developing exponentially and running at high speeds. With the increasing number of Internet users, computers have become the preferred target for complex attacks that require complex analyses to be detected. The Intrusion detection system (IDS) is created and turned into an important part of any modern network to protect the network from attacks. The IDS relies on string matching algorithms to identify network attacks, but these string matching algorithms consume a considerable amount of IDS processing time, thereby slows down the IDS performance. A new algorithm that can overcome the weakness of the IDS needs to be developed. Improving the multi-pattern matching algorithm ensure that an IDS can work properly and the limitations can be overcome. In this paper, we perform a comparison between our three multi-pattern matching algorithms; MP-KR, MPHQS and MPH-BMH with their corresponding original algorithms Kr, QS and BMH respectively. The experiments show that MPH-QS performs best among the proposed algorithms, followed by MPH-BMH, and MP-KR is the slowest. MPH-QS detects a large number of signature patterns in short time compared to other two algorithms. This finding can prove that the multi-pattern matching algorithms are more efficient in high-speed networks.

  5. String Formatting Considered Harmful for Novice Programmers

    ERIC Educational Resources Information Center

    Hughes, Michael C.; Jadud, Matthew C.; Rodrigo, Ma. Mercedes T.

    2010-01-01

    In Java, "System.out.printf" and "String.format" consume a specialised kind of string commonly known as a format string. In our study of first-year students at the Ateneo de Manila University, we discovered that format strings present a substantial challenge for novice programmers. Focusing on their first laboratory we found that 8% of all the…

  6. Bowed Strings

    NASA Astrophysics Data System (ADS)

    Rossing, Thomas D.; Hanson, Roger J.

    In the next eight chapters, we consider some aspects of the science of bowed string instruments, old and new. In this chapter, we present a brief discussion of bowed strings, a subject that will be developed much more thoroughly in Chap. 16. Chapters 13-15 discuss the violin, the cello, and the double bass. Chapter 17 discusses viols and other historic string instruments, and Chap. 18 discusses the Hutchins-Schelleng violin octet.

  7. Kibble-Zurek Scaling and String-Net Coarsening in Topologically Ordered Systems

    NASA Astrophysics Data System (ADS)

    Khemani, Vedika

    2014-03-01

    The classic formulation of the KZ mechanism involves phase transitions with broken symmetries. This work considers instead the the non-equilibrium dynamics of topologically ordered systems driven across a continuous phase transition into proximate phases with no, or reduced, topological order. This is interesting both as a non-trivial extension of the KZ ideas but also on account of the interest in topological phases in the theory of correlated electron systems. The work shows that the dynamics exhibits scaling in the spirit of Kibble and Zurek but now without the presence of symmetry breaking and a local order parameter. The late stages of the process are seen to exhibit a slow, coarsening dynamics for the string-net that underlies the physics of the topological phase, a potentially interesting signature of topological order. The work discusses phase transitions involving both abelian and non-abelian topological order.

  8. On Atwood's Machine with a Nonzero Mass String

    ERIC Educational Resources Information Center

    Tarnopolski, Mariusz

    2015-01-01

    Let us consider a classical high school exercise concerning two weights on a pulley and a string, illustrated in Fig. 1(a). A system like this is called an Atwood's machine and was invented by George Atwood in 1784 as a laboratory experiment to verify the mechanical laws of motion with constant acceleration. Nowadays, Atwood's machine is used for…

  9. Reliable timing systems for computer controlled accelerators

    NASA Astrophysics Data System (ADS)

    Knott, Jürgen; Nettleton, Robert

    1986-06-01

    Over the past decade the use of computers has set new standards for control systems of accelerators with ever increasing complexity coupled with stringent reliability criteria. In fact, with very slow cycling machines or storage rings any erratic operation or timing pulse will cause the loss of precious particles and waste hours of time and effort of preparation. Thus, for the CERN linac and LEAR (Low Energy Antiproton Ring) timing system reliability becomes a crucial factor in the sense that all components must operate practically without fault for very long periods compared to the effective machine cycle. This has been achieved by careful selection of components and design well below thermal and electrical limits, using error detection and correction where possible, as well as developing "safe" decoding techniques for serial data trains. Further, consistent structuring had to be applied in order to obtain simple and flexible modular configurations with very few components on critical paths and to minimize the exchange of information to synchronize accelerators. In addition, this structuring allows the development of efficient strategies for on-line and off-line fault diagnostics. As a result, the timing system for Linac 2 has, so far, been operating without fault for three years, the one for LEAR more than one year since its final debugging.

  10. Cosmic D-strings as axionic D-term strings

    NASA Astrophysics Data System (ADS)

    Blanco-Pillado, Jose J.; Dvali, Gia; Redi, Michele

    2005-11-01

    In this work we derive nonsingular BPS string solutions from an action that captures the essential features of a D-brane anti-D-brane system compactified to four dimensions. The model we consider is a supersymmetric Abelian Higgs model with a D-term potential coupled to an axion-dilaton multiplet. The strings in question are axionic D-term strings which we identify with the D-strings of type II string theory. In this picture the Higgs field represents the open string tachyon of the D-D¯ pair and the axion is dual to a Ramond-Ramond form. The crucial term allowing the existence of nonsingular BPS strings is the Fayet-Iliopoulos term, which is related to the tensions of the D-string and of the parent branes. Despite the presence of the axion, the strings are BPS and carry finite energy, due to the fact that the space gets very slowly decompactified away from the core, screening the long range axion field (or equivalently the theory approaches an infinitely weak 4D coupling). Within our 4D effective action we also identify another class of BPS string solutions (s-strings) which have no ten-dimensional analog, and can only exist after compactification.

  11. Cosmic D-strings as axionic D-term strings

    SciTech Connect

    Blanco-Pillado, Jose J.; Dvali, Gia; Redi, Michele

    2005-11-15

    In this work we derive nonsingular BPS string solutions from an action that captures the essential features of a D-brane-anti-D-brane system compactified to four dimensions. The model we consider is a supersymmetric Abelian Higgs model with a D-term potential coupled to an axion-dilaton multiplet. The strings in question are axionic D-term strings which we identify with the D-strings of type II string theory. In this picture the Higgs field represents the open string tachyon of the D-D pair and the axion is dual to a Ramond-Ramond form. The crucial term allowing the existence of nonsingular BPS strings is the Fayet-Iliopoulos term, which is related to the tensions of the D-string and of the parent branes. Despite the presence of the axion, the strings are BPS and carry finite energy, due to the fact that the space gets very slowly decompactified away from the core, screening the long range axion field (or equivalently the theory approaches an infinitely weak 4D coupling). Within our 4D effective action we also identify another class of BPS string solutions (s-strings) which have no ten-dimensional analog, and can only exist after compactification.

  12. Critical Systems Engineering Accelerator: Aerospace Demonstrator

    NASA Astrophysics Data System (ADS)

    Moreno, Ricardo; Fernandez, Gonzalo; Regada, Raul; Basanta, Luis; Alana, Elena; Del Carmen Lomba, Maria

    2014-08-01

    Nowadays, the complexity and functionality of space systems is increasing more and more. Safety critical systems have to guarantee strong safety and dependability constraints. This paper presents CRYSTAL (Critical sYSTem engineering AcceLeration), a cross-domain ARTEMIS project for increasing the efficiency of the embedded software development in the industry through the definition of an integrated tool chain. CRYSTAL involves four major application domains: Aerospace, Automotive, Rail and Medical Healthcare. The impact in the Space Domain will be evaluated through a demonstrator implemented using CRYSTAL framework: the Low Level Software for an Avionics Control Unit, capable to run Application SW for autonomous navigation, image acquisition control, data compression and/or data handling. Finally, the results achieved will be evaluated taking into account the ECSS (European Committee for Space Standardization) standards and procedures.

  13. Strings without supersymmetry

    NASA Astrophysics Data System (ADS)

    Adams, Allan Wilfred

    This dissertation examines the condensation of closed string tachyons in nonsupersymmetric spacetimes. Closed string tachyons signal instabilities of the spacetime background which make perturbation theory around the chosen vacuum inconsistent. Non-perturbative techniques developed in studying supersymmetric geometries provide a powerful set of tools with which to re-examine the classic problem of closed string tachyons. Such approaches allow remarkably controlled and complete descriptions of the condensation of closed string tachyons in a broad class of non-supersymmetric theories. The text begins with a discussion of closed string tachyons in non-supersymmetric orbifolds of AdS5 x S 5, using the orbifolded dual CFT to study non-perturbative features of the tachyonic instabilities in the orbifolded spacetime. We then discuss localized closed string tachyons in orbifolds of flat space which break spacetime supersymmetry only at isolated curvature singularities. Using worldsheet and D-probe techniques to follow these systems beyond perturbation theory, we show that these localized tachyons resolve the spacetime as they condense, leading generically to smooth and asymptotically supersymmetric spacetimes. Finally, we discuss a proposal for removing these instabilities from the perturbative string which is motivated by our results on non-supersymmetric orbifolds of the AdS/CFT correspondence.

  14. Kibble-Zurek scaling and string-net coarsening in topologically ordered systems.

    PubMed

    Chandran, Anushya; Burnell, F J; Khemani, Vedika; Sondhi, S L

    2013-10-01

    We consider the non-equilibrium dynamics of topologically ordered systems driven across a continuous phase transition into proximate phases with no, or reduced, topological order. This dynamics exhibits scaling in the spirit of Kibble and Zurek but now without the presence of symmetry breaking and a local order parameter. The late stages of the process are seen to exhibit a slow, coarsening dynamics for the string-net that underlies the physics of the topological phase, a potentially interesting signature of topological order. We illustrate these phenomena in the context of particular phase transitions out of the Abelian Z2 topologically ordered phase of the toric code/Z2 gauge theory, and the non-Abelian SU(2)k ordered phases of the relevant Levin-Wen models. PMID:24025618

  15. Kibble-Zurek scaling and string-net coarsening in topologically ordered systems.

    PubMed

    Chandran, Anushya; Burnell, F J; Khemani, Vedika; Sondhi, S L

    2013-10-01

    We consider the non-equilibrium dynamics of topologically ordered systems driven across a continuous phase transition into proximate phases with no, or reduced, topological order. This dynamics exhibits scaling in the spirit of Kibble and Zurek but now without the presence of symmetry breaking and a local order parameter. The late stages of the process are seen to exhibit a slow, coarsening dynamics for the string-net that underlies the physics of the topological phase, a potentially interesting signature of topological order. We illustrate these phenomena in the context of particular phase transitions out of the Abelian Z2 topologically ordered phase of the toric code/Z2 gauge theory, and the non-Abelian SU(2)k ordered phases of the relevant Levin-Wen models.

  16. Microgravity acceleration modeling for orbital systems

    NASA Technical Reports Server (NTRS)

    Knabe, Walter; Baugher, Charles R. (Editor)

    1990-01-01

    In view of the decisive importance of a disturbance-free environment on the Space Station, and on other orbital systems, for materials processing experiments, a theoretical and semi-experimental analysis of the acceleration environment to be expected on large orbiting spacecraft was undertaken. A unified model of such spacecraft cannot be established; therefore, a number of sub-models representing major components of typical large spacecraft must be investigated. In order to obtain experimental data of forces, a typical spacecraft - an engineering model of the Spacelab - was suspended on long ropes in a high-bay hangar, and equipped with a number of accelerometers. Active components on the Spacelab (fans, pumps, air conditioners, valves, levers) were operated, and astronautics moved boxes, drawers, sleds, and their own bodies. Generally speaking, the response of the Spacelab structure was very similar to the environment measured on Spacelabs SL-1, SL-2, and D-1. At frequencies in the broad range between 1 and about 100 Hz, acceleration peaks reached values of 10(exp -3) and 10(exp -2) g sub o, and even higher.

  17. Systems and methods for the magnetic insulation of accelerator electrodes in electrostatic accelerators

    DOEpatents

    Grisham, Larry R

    2013-12-17

    The present invention provides systems and methods for the magnetic insulation of accelerator electrodes in electrostatic accelerators. Advantageously, the systems and methods of the present invention improve the practically obtainable performance of these electrostatic accelerators by addressing, among other things, voltage holding problems and conditioning issues. The problems and issues are addressed by flowing electric currents along these accelerator electrodes to produce magnetic fields that envelope the accelerator electrodes and their support structures, so as to prevent very low energy electrons from leaving the surfaces of the accelerator electrodes and subsequently picking up energy from the surrounding electric field. In various applications, this magnetic insulation must only produce modest gains in voltage holding capability to represent a significant achievement.

  18. Development of Acceleration Sensor and Acceleration Evaluation System for Super-Low-Range Frequencies

    NASA Astrophysics Data System (ADS)

    Asano, Shogo; Matsumoto, Hideki

    2001-05-01

    This paper describes the development process for acceleration sensors used on automobiles and an acceleration evaluation system designed specifically for acceleration at super-low-range frequencies. The features of the newly developed sensor are as follows. 1) Original piezo-bimorph design based on a disc-center-fixed structure achieves pyroeffect cancelling and stabilization of sensor characteristics and enables the detection of the acceleration of 0.0009 G at the super-low-range-frequency of 0.03 Hz. 2) The addition of a self-diagnostic function utilizing the characteristics of piezoceramics enables constant monitoring of sensor failure. The frequency range of acceleration for accurate vehicle motion control is considered to be from DC to about 50 Hz. However, the measurement of acceleration in the super-low-range frequency near DC has been difficult because of mechanical and electrical noise interruption. This has delayed the development of the acceleration sensor for automotive use. We have succeeded in the development of an acceleration evaluation system for super-low-range frequencies from 0.015 Hz to 2 Hz with detection of the acceleration range from 0.0002 G (0.2 gal) to 1 G, as well as the development of a piezoelectric-type acceleration sensor for automotive use.

  19. Playing a 3-Stringed Violin: Innovation via the Joint Evolution of People, Process, and Knowledge Management System

    NASA Technical Reports Server (NTRS)

    Cooper, Lynne P.

    2010-01-01

    Users continuously evaluate the value and performance of their Knowledge Management Systems (KMS). As suggested by a punctuated socio-technical system process model, today's success can quickly become tomorrow's failure should the KMS fail to meet evolving needs and expectations. The more deeply a tool is embedded in the actual work process, the more vulnerable it is to emergent changes and perturbations. This paper uses the metaphor of a "3-stringed violin" to explore how differing levels of user knowledge about tools and processes can lead to system perturbations and how the active involvement of other actors can dampen the impact of perturbations, i.e., help the system survive the operational equivalent of a broken string. Recommendations suggest ways to increase system resiliency and contribute to incremental innovation.

  20. BIOCONAID System (Bionic Control of Acceleration Induced Dimming). Final Report.

    ERIC Educational Resources Information Center

    Rogers, Dana B.; And Others

    The system described represents a new technique for enhancing the fidelity of flight simulators during high acceleration maneuvers. This technique forces the simulator pilot into active participation and energy expenditure similar to the aircraft pilot undergoing actual accelerations. The Bionic Control of Acceleration Induced Dimming (BIOCONAID)…

  1. Cosmic strings

    NASA Technical Reports Server (NTRS)

    Bennett, David P.

    1988-01-01

    Cosmic strings are linear topological defects which are predicted by some grand unified theories to form during a spontaneous symmetry breaking phase transition in the early universe. They are the basis for the only theories of galaxy formation aside from quantum fluctuations from inflation based on fundamental physics. In contrast to inflation, they can also be observed directly through gravitational lensing and their characterisitc microwave background anisotropy. It was recently discovered that details of cosmic string evolution are very differnt from the so-called standard model that was assumed in most of the string-induced galaxy formation calculations. Therefore, the details of galaxy formation in the cosmic string models are currently very uncertain.

  2. Cosmic strings

    SciTech Connect

    Bennett, D.P.

    1988-07-01

    Cosmic strings are linear topological defects that are predicted by some grand unified theories to form during a spontaneous symmetry breaking phase transition in the early universe. They are the basis for the only theories of galaxy formation aside from quantum fluctuations from inflation that are based on fundamental physics. In contrast to inflation, they can also be observed directly through gravitational lensing and their characteristic microwave background anistropy. It has recently been discovered by F. Bouchet and myself that details of cosmic string evolution are very different from the so-called ''standard model'' that has been assumed in most of the string induced galaxy formation calculations. Therefore, the details of galaxy formation in the cosmic string models are currently very uncertain. 29 refs., 9 figs.

  3. Dark strings

    SciTech Connect

    Vachaspati, Tanmay

    2009-09-15

    Recent astrophysical observations have motivated novel theoretical models of the dark matter sector. A class of such models predicts the existence of GeV scale cosmic strings that communicate with the standard model sector by Aharonov-Bohm interactions with electrically charged particles. We discuss the cosmology of these 'dark strings' and investigate possible observational signatures. More elaborate dark sector models are argued to contain hybrid topological defects that may also have observational signatures.

  4. Twisted superconducting semilocal strings

    NASA Astrophysics Data System (ADS)

    Forgács, Péter; Reuillon, Sébastien; Volkov, Mikhail S.

    2006-09-01

    A new class of twisted, current carrying, stationary, straight string solutions having finite energy per unit length is constructed numerically in an extended Abelian Higgs model with global SU(2) symmetry. The new solutions correspond to deformations of the embedded Abrikosov Nielsen Olesen (ANO) vortices by a twist—a relative coordinate dependent phase between the two Higgs fields. The twist induces a global current flowing through the string, and the deformed solutions bifurcate with the ANO vortices in the limit of vanishing current. For each value of the winding number n=1,2,… (determining the magnetic flux through the plane orthogonal to the string) there are n distinct, two-parametric families of solutions. One of the continuously varying parameters is the twist, or the corresponding current, the other one can be chosen to be the momentum of the string. For fixed values of the momentum and twist, the n distinct solutions have different energies and can be viewed as a lowest energy “fundamental” string and its n-1 “excitations” characterized by different values of their “polarization”. The latter is defined as the ratio of the angular momentum of the vortex and its momentum. In their rest frame the twisted vortices have lower energy than the embedded ANO vortices and could be of considerable importance in various physical systems (from condensed matter to cosmic strings).

  5. Tripartite entanglement of fermionic system in accelerated frames

    SciTech Connect

    Khan, Salman

    2014-09-15

    The dynamics of tripartite entanglement of fermionic system in noninertial frames through linear contraction criterion when one or two observers are accelerated is investigated. In one observer accelerated case the entanglement measurement is not invariant with respect to the partial realignment of different subsystems and for two observers accelerated case it is invariant. It is shown that the acceleration of the frame does not generate entanglement in any bipartite subsystems. Unlike the bipartite states, the genuine tripartite entanglement does not completely vanish in both one observer accelerated and two observers accelerated cases even in the limit of infinite acceleration. The degradation of tripartite entanglement is fast when two observers are accelerated than when one observer is accelerated. It is shown that tripartite entanglement is a better resource for quantum information processing than the bipartite entanglement in noninertial frames. - Highlights: • Tripartite entanglement of fermionic system in noninertial frames is studied. • Linear contraction criterion for quantifying tripartite entanglement is used. • Acceleration does not produce any bipartite entanglement. • The invariance of entanglement quantifier depends on accelerated observers. • The tripartite entanglement degrades against the acceleration, it never vanishes.

  6. New ways to look for cosmic strings

    NASA Astrophysics Data System (ADS)

    Beresnyak, Andrey

    2015-08-01

    Cosmic strings are linear topological defects which are hypothesized to be produced during inflation. Most searches for strings have been relying on the string's lensing of background galaxies or CMB. However, the interaction of the string with ordinary gas will produce several detectable signatures. I will explain how to obtain the solution for the supersonic flow of the collisional gas past the cosmic string. This solution has two planar shocks with shock compression ratio that depend on the angle defect of the string and its speed. These shocks compress and heat the gas, which should be detectable in high-z HI emission. Furthermore, in the present Universe, colliding with ionized rarefied HII gas, the string should produce particle acceleration at the shock and corresponding radio emission. The consequences of such collision will persist for cosmological timescales, so we should look for several unusual large-scale radio sources, typically a cluster radio halo size, situated on a single spatial plane.

  7. Advanced Microgravity Acceleration Measurement Systems (AMAMS) Being Developed

    NASA Technical Reports Server (NTRS)

    Sicker, Ronald J.; Kacpura, Thomas J.

    2003-01-01

    The Advanced Microgravity Acceleration Measurement Systems (AMAMS) project is part of NASA s Instrument Technology Development program to develop advanced sensor systems. The primary focus of the AMAMS project is to develop microelectromechanical systems (MEMS) for acceleration sensor systems to replace existing electromechanical sensor systems presently used to assess relative gravity levels aboard spacecraft. These systems are used to characterize both vehicle and payload responses to low-gravity vibroacoustic environments. The collection of microgravity acceleration data is useful to the microgravity life sciences, microgravity physical sciences, and structural dynamics communities. The inherent advantages of semiconductor-based systems are reduced size, mass, and power consumption, with enhanced long-term calibration stability.

  8. Using string alignment in a query-by-humming system for real world applications

    NASA Astrophysics Data System (ADS)

    Sailer, Christian

    2005-09-01

    Though query by humming (i.e., retrieving music or information about music by singing a characteristic melody) has been a popular research topic during the past decade, few approaches have reached a level of usefulness beyond mere scientific interest. One of the main problems is the inherent contradiction between error tolerance and dicriminative power in conventional melody matching algorithms that rely on a melody contour approach to handle intonation or transcription errors. Adopting the string matching/alignment techniques from bioinformatics to melody sequences allows to directly assess the similarity between two melodies. This method takes an MPEG-7 compliant melody sequence (i.e., a list of note intervals and length ratios) as query and evaluates the steps necessary to transform it into the reference sequence. By introducing a musically founded cost-of-replace function and an adequate post processing, this method yields a measure for melodic similarity. Thus it is possible to construct a query by humming system that can properly discriminate between thousands of melodies and still be sufficiently error tolerant to be used by untrained singers. The robustness has been verified in extensive tests and real world applications.

  9. System and method for damping vibration in a drill string using a magnetorheological damper

    DOEpatents

    Wassell, Mark Ellsworth; Burgess, Daniel E.; Barbely, Jason R.

    2012-01-03

    A system for damping vibration in a drill string can include a magnetorheological fluid valve assembly having a supply of a magnetorheological fluid, a first member, and a second member capable of moving in relation to first member in response to vibration of the drill bit. The first and second members define a first and a second chamber for holding the fluid. Fluid can flow between the first and second chambers in response to the movement of the second member in relation to the first member. The valve assembly can also include a coil for inducing a magnetic field that alters the resistance of the magnetorheological fluid to flow between the first and second chambers, thereby increasing the damping provided by the valve. A remnant magnetic field is induced in one or more components of the magnetorheological fluid valve during operation that can be used to provide the magnetic field for operating the valve so as to eliminate the need to energize the coils during operation except temporarily when changing the amount of damping required, thereby eliminating the need for a turbine alternator power the magnetorheological fluid valve. A demagnetization cycle can be used to reduce the remnant magnetic field when necessary.

  10. Cosmic strings and superconducting cosmic strings

    NASA Technical Reports Server (NTRS)

    Copeland, Edmund

    1988-01-01

    The possible consequences of forming cosmic strings and superconducting cosmic strings in the early universe are discussed. Lecture 1 describes the group theoretic reasons for and the field theoretic reasons why cosmic strings can form in spontaneously broken gauge theories. Lecture 2 discusses the accretion of matter onto string loops, emphasizing the scenario with a cold dark matter dominated universe. In lecture 3 superconducting cosmic strings are discussed, as is a mechanism which leads to the formation of structure from such strings.

  11. Presentation on a Space Acceleration Measurement System (SAMS)

    NASA Technical Reports Server (NTRS)

    Chase, Theodore L.

    1990-01-01

    The primary objective of the Space Acceleration Measurement Systems (SAMS) project is to provide an acceleration measurement system capable of serving a wide variety of space experiments. The design of the system being developed under this project takes into consideration requirements for experiments located in the middeck, in the orbiter bay, and in Spacelab. In addition to measuring, conditioning, and recording accelerations, the system will be capable of performing complex calculations and interactive control. The main components consist of a remote triaxial optical storage device. In operation, the triaxial sensor head produces output signals in response to acceleration inputs. These signals are preamplified, filtered and converted into digital data which is then transferred to optical memory. The system design is modular, facilitating both software and hardware upgrading as technology advances. Two complete acceleration measurement flight systems will be build and tested under this project.

  12. Plucked Strings

    NASA Astrophysics Data System (ADS)

    Rossing, Thomas D.

    In the next ten chapters we will discuss the science of plucked string instruments. Acoustic guitars and lutes are discussed in Chap. 3. Portuguese guitars, used in fado music, are discussed in Chap. 4 and guitars in Chap. 5, while electric guitars are discussed in Chap. 22. Banjos are discussed in Chap. 5, while mandolins are the subject of Chap. 6. Zithers and psalteries, especially Baltic psalteries, are discussed in Chap. 7. Harpsichords are discussed in Chap. 8, while harps are discussed in Chap. 9 and 10. Finally, plucked string instruments from Asia, such as the kito, shamisen, biwa, gayageum, geomungo, ch'in, p'I-p'a, and sitar are discussed in Chap. 11. These instruments are very different in character and in their musical roles, but they all depend upon plucked strings vibrating and exciting one or more soundboards or radiating surfaces.

  13. String method for calculation of minimum free-energy paths in Cartesian space in freely-tumbling systems.

    PubMed

    Branduardi, Davide; Faraldo-Gómez, José D

    2013-09-10

    The string method is a molecular-simulation technique that aims to calculate the minimum free-energy path of a chemical reaction or conformational transition, in the space of a pre-defined set of reaction coordinates that is typically highly dimensional. Any descriptor may be used as a reaction coordinate, but arguably the Cartesian coordinates of the atoms involved are the most unprejudiced and intuitive choice. Cartesian coordinates, however, present a non-trivial problem, in that they are not invariant to rigid-body molecular rotations and translations, which ideally ought to be unrestricted in the simulations. To overcome this difficulty, we reformulate the framework of the string method to integrate an on-the-fly structural-alignment algorithm. This approach, referred to as SOMA (String method with Optimal Molecular Alignment), enables the use of Cartesian reaction coordinates in freely tumbling molecular systems. In addition, this scheme permits the dissection of the free-energy change along the most probable path into individual atomic contributions, thus revealing the dominant mechanism of the simulated process. This detailed analysis also provides a physically-meaningful criterion to coarse-grain the representation of the path. To demonstrate the accuracy of the method we analyze the isomerization of the alanine dipeptide in vacuum and the chair-to-inverted-chair transition of β-D mannose in explicit water. Notwithstanding the simplicity of these systems, the SOMA approach reveals novel insights into the atomic mechanism of these isomerizations. In both cases, we find that the dynamics and the energetics of these processes are controlled by interactions involving only a handful of atoms in each molecule. Consistent with this result, we show that a coarse-grained SOMA calculation defined in terms of these subsets of atoms yields nearidentical minimum free-energy paths and committor distributions to those obtained via a highly-dimensional string. PMID

  14. String method for calculation of minimum free-energy paths in Cartesian space in freely-tumbling systems.

    PubMed

    Branduardi, Davide; Faraldo-Gómez, José D

    2013-09-10

    The string method is a molecular-simulation technique that aims to calculate the minimum free-energy path of a chemical reaction or conformational transition, in the space of a pre-defined set of reaction coordinates that is typically highly dimensional. Any descriptor may be used as a reaction coordinate, but arguably the Cartesian coordinates of the atoms involved are the most unprejudiced and intuitive choice. Cartesian coordinates, however, present a non-trivial problem, in that they are not invariant to rigid-body molecular rotations and translations, which ideally ought to be unrestricted in the simulations. To overcome this difficulty, we reformulate the framework of the string method to integrate an on-the-fly structural-alignment algorithm. This approach, referred to as SOMA (String method with Optimal Molecular Alignment), enables the use of Cartesian reaction coordinates in freely tumbling molecular systems. In addition, this scheme permits the dissection of the free-energy change along the most probable path into individual atomic contributions, thus revealing the dominant mechanism of the simulated process. This detailed analysis also provides a physically-meaningful criterion to coarse-grain the representation of the path. To demonstrate the accuracy of the method we analyze the isomerization of the alanine dipeptide in vacuum and the chair-to-inverted-chair transition of β-D mannose in explicit water. Notwithstanding the simplicity of these systems, the SOMA approach reveals novel insights into the atomic mechanism of these isomerizations. In both cases, we find that the dynamics and the energetics of these processes are controlled by interactions involving only a handful of atoms in each molecule. Consistent with this result, we show that a coarse-grained SOMA calculation defined in terms of these subsets of atoms yields nearidentical minimum free-energy paths and committor distributions to those obtained via a highly-dimensional string.

  15. Unifying inflation with late-time acceleration by a BIonic system

    NASA Astrophysics Data System (ADS)

    Sepehri, Alireza; Rahaman, Farook; Setare, Mohammad Reza; Pradhan, Anirudh; Capozziello, Salvatore; Sardar, Iftikar Hossain

    2015-07-01

    We propose a cosmological model that unifies inflation, deceleration and acceleration phases of expansion history by a BIonic system. At the beginning, there are k black fundamental strings that transited to the BIon configuration at a given corresponding point. Here, two coupled universes, brane and antibrane, are created interacting each other through a wormhole and inflate. With decreasing temperature, the energy of this wormhole flows into the universe branes and leads to inflation. After a short time, the wormhole evaporates, the inflation ends and a deceleration epoch starts. By approaching the brane and antibrane universes together, a tachyon is born, grows and causes the creation of a new wormhole. At this time, the brane and antibrane universes result connected again and the late-time acceleration era of the universe begins. We compare our model with previous unified phantom models and observational data obtaining some cosmological parameters like temperature in terms of time. We also find that deceleration parameter is negative during inflation and late-time acceleration epochs, while it is positive during the deceleration era. This means that the model is consistent, in principle, with cosmological observations.

  16. Teaching Strings.

    ERIC Educational Resources Information Center

    New York State Education Dept., Albany. Bureau of Secondary Curriculum Development.

    Intended primarily for use by instrumental music teachers who do not have a major concentration in strings, this guide provides pertinent basic resources, materials, teaching--learning expectation, and a general overall guide to achievement levels at various stages of development. Discussions are presented of Choosing the Proper Method Book,…

  17. Small system for tritium accelerator mass spectrometry

    DOEpatents

    Roberts, M.L.; Davis, J.C.

    1993-02-23

    Apparatus for ionizing and accelerating a sample containing isotopes of hydrogen and detecting the ratios of hydrogen isotopes contained in the sample is disclosed. An ion source generates a substantially linear ion beam including ions of tritium from the sample. A radio-frequency quadrupole accelerator is directly coupled to and axially aligned with the source at an angle of substantially zero degrees. The accelerator accelerates species of the sample having different mass to different energy levels along the same axis as the ion beam. A spectrometer is used to detect the concentration of tritium ions in the sample. In one form of the invention, an energy loss spectrometer is used which includes a foil to block the passage of hydrogen, deuterium and [sup 3]He ions, and a surface barrier or scintillation detector to detect the concentration of tritium ions. In another form of the invention, a combined momentum/energy loss spectrometer is used which includes a magnet to separate the ion beams, with Faraday cups to measure the hydrogen and deuterium and a surface barrier or scintillation detector for the tritium ions.

  18. Small system for tritium accelerator mass spectrometry

    DOEpatents

    Roberts, Mark L.; Davis, Jay C.

    1993-01-01

    Apparatus for ionizing and accelerating a sample containing isotopes of hydrogen and detecting the ratios of hydrogen isotopes contained in the sample is disclosed. An ion source generates a substantially linear ion beam including ions of tritium from the sample. A radio-frequency quadrupole accelerator is directly coupled to and axially aligned with the source at an angle of substantially zero degrees. The accelerator accelerates species of the sample having different mass to different energy levels along the same axis as the ion beam. A spectrometer is used to detect the concentration of tritium ions in the sample. In one form of the invention, an energy loss spectrometer is used which includes a foil to block the passage of hydrogen, deuterium and .sup.3 He ions, and a surface barrier or scintillation detector to detect the concentration of tritium ions. In another form of the invention, a combined momentum/energy loss spectrometer is used which includes a magnet to separate the ion beams, with Faraday cups to measure the hydrogen and deuterium and a surface barrier or scintillation detector for the tritium ions.

  19. Lessons from Adaptive Level One Accelerator (ALOA) System Implementation

    NASA Technical Reports Server (NTRS)

    Patel, Umesh D.; Brambora, Clifford; Ghuman, Parminder; Day, John H. (Technical Monitor)

    2001-01-01

    The Adaptive Level One Accelerator (ALOA) system was developed as part of the Earth Science Data and Information System (ESDIS) project. The reconfigurable computing technologies were investigated for Level 1 satellite telemetry data processing to achieve computing acceleration and cost reduction for the next-generation Level 1 data processing systems. The MODIS instrument calibration algorithm was implemented using reconfigurable a computer. The system development process and the lessons learned throughout the design cycle are summarized in this paper.

  20. Search for critical point indications in long-range correlations by energy and system size scanning in string fusion approach

    NASA Astrophysics Data System (ADS)

    Kovalenko, V. N.; Vechernin, V. V.

    2016-01-01

    The ultrarelativistic collisions of heavy and light ions in the center-of-mass energy range from a few up to a hundred GeV per nucleon have been considered in string fusion approach. A Monte Carlo model of proton-proton, proton-nucleus, and nucleus-nucleus collisions has been developed, which takes into account both the string fusion and the finite rapidity length of strings, implementing the hadronic scattering through the interaction of color dipoles. It well describes the proton-nucleus and nucleus-nucleus collisions at the partonic level without using Glauber model of nuclear collisions. All parameters are fixed using experimental data on inelastic cross section and multiplicity. In the framework of the model, we performed a beam energy and system size scan and studied the behaviour of n-n, pt-n and pt-pt long-range correlation coefficients. The detailed modeling of the event by event charged particles production allowed to provide predictions in the conditions close to the experimental ones allowing a direct comparison to the data.

  1. Proliferation Potential of Accelerator-Drive Systems: Feasibility Calculations

    SciTech Connect

    Riendeau, C.D.; Moses, D.L.; Olson, A.P.

    1998-11-01

    Accelerator-driven systems for fissile materials production have been proposed and studied since the early 1950s. Recent advances in beam power levels for small accelerators have raised the possibility that such use could be feasible for a potential proliferator. The objective of this study is to review the state of technology development for accelerator-driven spallation neutron sources and subcritical reactors. Energy and power requirements were calculated for a proton accelerator-driven neutron spallation source and subcritical reactors to produce a significant amount of fissile material--plutonium.

  2. Three-grid accelerator system for an ion propulsion engine

    NASA Technical Reports Server (NTRS)

    Brophy, John R. (Inventor)

    1994-01-01

    An apparatus is presented for an ion engine comprising a three-grid accelerator system with the decelerator grid biased negative of the beam plasma. This arrangement substantially reduces the charge-exchange ion current reaching the accelerator grid at high tank pressures, which minimizes erosion of the accelerator grid due to charge exchange ion sputtering, known to be the major accelerator grid wear mechanism. An improved method for life testing ion engines is also provided using the disclosed apparatus. In addition, the invention can also be applied in materials processing.

  3. Electronic accelerator pedal optimal design of intelligent test system

    NASA Astrophysics Data System (ADS)

    Li, Quailing; Lin, Min; Guo, Bin; Luo, Zai

    2010-12-01

    Developed an intelligent test system for the electronic accelerator pedal, and optimized it. The system uses the three-dimensional motion platform driven by servo motor to realize to control the movement of the electronic accelerator pedal automatically and uses the least squares method to optimize the data for the electronic accelerator pedal which is integrated with linear Hall sensors. Carried on the test experiment to the double electric potential signal output electron accelerator pedal and the results show that the system has excellent dynamic and static performance, and the change of motor parameters and load disturbances has strong robustness. Performance indicators have reached the Euro III emission standard configuration of the electronic accelerator pedal and the new technical requirements.

  4. FPGA-accelerated algorithm for the regular expression matching system

    NASA Astrophysics Data System (ADS)

    Russek, P.; Wiatr, K.

    2015-01-01

    This article describes an algorithm to support a regular expressions matching system. The goal was to achieve an attractive performance system with low energy consumption. The basic idea of the algorithm comes from a concept of the Bloom filter. It starts from the extraction of static sub-strings for strings of regular expressions. The algorithm is devised to gain from its decomposition into parts which are intended to be executed by custom hardware and the central processing unit (CPU). The pipelined custom processor architecture is proposed and a software algorithm explained accordingly. The software part of the algorithm was coded in C and runs on a processor from the ARM family. The hardware architecture was described in VHDL and implemented in field programmable gate array (FPGA). The performance results and required resources of the above experiments are given. An example of target application for the presented solution is computer and network security systems. The idea was tested on nearly 100,000 body-based viruses from the ClamAV virus database. The solution is intended for the emerging technology of clusters of low-energy computing nodes.

  5. Techniques for increasing the reliability of accelerator control system electronics

    SciTech Connect

    Utterback, J.

    1993-09-01

    As the physical size of modern accelerators becomes larger and larger, the number of required control system circuit boards increases, and the probability of one of those circuit boards failing while in service also increases. In order to do physics, the experimenters need the accelerator to provide beam reliably with as little down time as possible. With the advent of colliding beams physics, reliability becomes even more important due to the fact that a control system failure can cause the loss of painstakingly produced antiprotons. These facts prove the importance of keeping reliability in mind when designing and maintaining accelerator control system electronics.

  6. Accelerated Superposition State Molecular Dynamics for Condensed Phase Systems.

    PubMed

    Ceotto, Michele; Ayton, Gary S; Voth, Gregory A

    2008-04-01

    An extension of superposition state molecular dynamics (SSMD) [Venkatnathan and Voth J. Chem. Theory Comput. 2005, 1, 36] is presented with the goal to accelerate timescales and enable the study of "long-time" phenomena for condensed phase systems. It does not require any a priori knowledge about final and transition state configurations, or specific topologies. The system is induced to explore new configurations by virtue of a fictitious (free-particle-like) accelerating potential. The acceleration method can be applied to all degrees of freedom in the system and can be applied to condensed phases and fluids. PMID:26620930

  7. Summing Planar Bosonic Open Strings

    SciTech Connect

    Bardakci, Korkut

    2006-02-16

    In earlier work, planar graphs of massless {phi}{sup 3} theory were summed with the help of the light cone world sheet picture and the mean field approximation. In the present article, the same methods are applied to the problem of summing planar bosonic open strings. They find that in the ground state of the system, string boundaries form a condensate on the world sheet, and a new string emerges from this summation. Its slope is always greater than the initial slope, and it remains non-zero even when the initial slope is set equal to zero. If they assume the initial string tends to a field a theory in the zero slope limit, this result provides evidence for string formation in field theory.

  8. Solid state power systems for DC and RF accelerators

    NASA Astrophysics Data System (ADS)

    Adler, R. J.; Richter-Sand, R. J.

    1999-06-01

    Modern accelerator applications require high average and peak powers—particularly RF accelerators and DC accelerators. In many of these applications, it is possible to replace tubes in the power systems with solid state power supplies. In this paper we outline work which we have performed in developing solid state pulsed and CW pulsed power systems for RF linacs and for DC accelerators. We have built and successfully tested a 125 kV, 2.5 MW peak, 60 kW average pulsed power system which is well suited to driving ion beam linacs. This system is modular, with 3 modules capable of driving a large Klystron. The system has been extensively tested with both resistive and fault loads. This type of power supply promises to be less than half as expensive as a conventional thyratron modulator, with considerably more flexibility in pulse duration. We have also powered our Nested High Voltage (NHV) accelerators with a solid state power supply using IGBTs. This type of supply is suitable for both NHV machines, and other Dynamitron style accelerators. Pulsed burst mode excitation of this type of power supply allows us to maintain 1 MV in the NHV accelerator with less than three hundred watts of idling power.

  9. Solid state power systems for DC and RF accelerators

    SciTech Connect

    Adler, R. J.; Richter-Sand, R. J.

    1999-06-10

    Modern accelerator applications require high average and peak powers - particularly RF accelerators and DC accelerators. In many of these applications, it is possible to replace tubes in the power systems with solid state power supplies. In this paper we outline work which we have performed in developing solid state pulsed and CW pulsed power systems for RF linacs and for DC accelerators. We have built and successfully tested a 125 kV, 2.5 MW peak, 60 kW average pulsed power system which is well suited to driving ion beam linacs. This system is modular, with 3 modules capable of driving a large Klystron. The system has been extensively tested with both resistive and fault loads. This type of power supply promises to be less than half as expensive as a conventional thyratron modulator, with considerably more flexibility in pulse duration. We have also powered our Nested High Voltage (NHV) accelerators with a solid state power supply using IGBTs. This type of supply is suitable for both NHV machines, and other Dynamitron style accelerators. Pulsed burst mode excitation of this type of power supply allows us to maintain 1 MV in the NHV accelerator with less than three hundred watts of idling power.

  10. Study of Some Properties of Cosmic Strings.

    NASA Astrophysics Data System (ADS)

    Aryal, Mukunda Mani

    This work deals with some of the properties of stringlike topological structures that can arise in reasonable models of grand unified theories. We study stringlike structures formed when a simply or multiply connected group breaks spontaneously to an unbroken subgroup. If the original group is simply connected then the unbroken subgroup has to have two or more disconnected components in order to produce strings. If the number of such components of the unbroken subgroup is n, we call the resulting string Zn strings. In this work I want to study some properties of Z2 and Z3 strings. In some cases the unbroken subgroup Z2 can be embedded in different U(1) subgroups of G, giving topologically equivalent but dynamically different strings. We obtain the string mass in terms of the Higg's field vacuum expectation value of various values of the gauge and quartic Higg's field coupling constants by numerical calculation. We find that in a wide range of realistic cases the lowest mass embedding gives strings which are gauge equivalent to antistrings, in which case solitons of Hindmarsh and Kibble do not occur. Statistical properties of Z2 and Z3 strings produced in a phase transition in the early universe are studied using a Monte Carlo simulation. For Z3 strings it is shown that the system is dominated by one infinite network of Brownian strings. We calculate the gravitational field of a global string and conclude that distinguishing a global string from a gauge string observationally appears difficult at best in case such strings actually exist in nature. Our calculation is in weak field approximation. We also calculate the gravitational field of a cosmic string passing through a Schwarzschild black hole. We consider the thermodynamics of such an object. It is shown that S = (1/4)A where S is the entropy and A is the horizon area. Finally we discuss some problems in string electrodynamics.

  11. The "Magic" String

    ERIC Educational Resources Information Center

    Hoover, Todd F.

    2010-01-01

    The "Magic" String is a discrepant event that includes a canister with what appears to be the end of two strings protruding from opposite sides of it. Due to the way the strings are attached inside the canister, it appears as if the strings can magically switch the way they are connected. When one string end is pulled, the observer's expectation…

  12. Accelerator control system at KEKB and the linac

    NASA Astrophysics Data System (ADS)

    Akiyama, Atsuyoshi; Furukawa, Kazuro; Kadokura, Eiichi; Kurashina, Miho; Mikawa, Katsuhiko; Nakamura, Tatsuro; Odagiri, Jun-ichi; Satoh, Masanori; Suwada, Tsuyoshi

    2013-03-01

    KEKB has completed all of the technical milestones and has offered important insights into the flavor structure of elementary particles, especially CP violation. The accelerator control system at KEKB and the injector linac was initiated by a combination of scripting languages at the operation layer and EPICS (experimental physics and industrial control system) at the equipment layer. During the project, many features were implemented to achieve extreme performance from the machine. In particular, the online linkage to the accelerator simulation played an essential role. In order to further improve the reliability and flexibility, two major concepts were additionally introduced later in the project, namely, channel access everywhere and dual-tier controls. Based on the improved control system, a virtual accelerator concept was realized, allowing the single injector linac to serve as three separate injectors to KEKB's high-energy ring, low-energy ring, and Photon Factory, respectively. These control technologies are indispensable for future particle accelerators.

  13. COMPACT PROTON INJECTOR AND FIRST ACCELERATOR SYSTEM TEST FOR COMPACT PROTON DIELECTRIC WALL CANCER THERAPY ACCELERATOR

    SciTech Connect

    Chen, Y; Guethlein, G; Caporaso, G; Sampayan, S; Blackfield, D; Cook, E; Falabella, S; Harris, J; Hawkins, S; Nelson, S; Poole, B; Richardson, R; Watson, J; Weir, J; Pearson, D

    2009-04-23

    A compact proton accelerator for cancer treatment is being developed by using the high-gradient dielectric insulator wall (DWA) technology [1-4]. We are testing all the essential DWA components, including a compact proton source, on the First Article System Test (FAST). The configuration and progress on the injector and FAST will be presented.

  14. Relational String Verification Using Multi-track Automata

    NASA Astrophysics Data System (ADS)

    Yu, Fang; Bultan, Tevfik; Ibarra, Oscar H.

    Verification of string manipulation operations is a crucial problem in computer security. In this paper, we present a new relational string verification technique based on multi-track automata. Our approach is capable of verifying properties that depend on relations among string variables. This enables us to prove that vulnerabilities that result from improper string manipulation do not exist in a given program. Our main contributions in this paper can be summarized as follows: (1) We formally characterize the string verification problem as the reachability analysis of string systems and show decidability/undecidability results for several string analysis problems. (2) We develop a sound symbolic analysis technique for string verification that over-approximates the reachable states of a given string system using multi-track automata and summarization. (3) We evaluate the presented techniques with respect to several string analysis benchmarks extracted from real web applications.

  15. Helium refrigeration systems for super-conducting accelerators

    SciTech Connect

    Ganni, V.

    2015-12-04

    Many of the present day accelerators are based on superconducting technology which requires 4.5-K or 2-K helium refrigeration systems. These systems utilize superconducting radio frequency (SRF) cavities and/or superconducting magnets which are packaged into vacuum vessels known as cryo-modules (CM’s). Many of the present day accelerators are optimized to operate primarily at around 2-K, requiring specialized helium refrigeration systems which are cost intensive to produce and to operate. Some of the cryogenic refrigeration system design considerations for these challenging applications are discussed.

  16. Space Acceleration Measurement System (SAMS)/Orbital Acceleration Research Experiment (OARE)

    NASA Technical Reports Server (NTRS)

    Hakimzadeh, Roshanak

    1998-01-01

    The Life and Microgravity Spacelab (LMS) payload flew on the Orbiter Columbia on mission STS-78 from June 20th to July 7th, 1996. The LMS payload on STS-78 was dedicated to life sciences and microgravity experiments. Two accelerometer systems managed by the NASA Lewis Research Center (LERC) flew to support these experiments, namely the Orbital Acceleration Research Experiment (OARE) and the Space Acceleration Measurements System (SAMS). In addition, the Microgravity Measurement Assembly (NOAA), managed by the European Space Research and Technology Center (ESA/ESTEC), and sponsored by NASA, collected acceleration data in support of the experiments on-board the LMS mission. OARE downlinked real-time quasi-steady acceleration data, which was provided to the investigators. The SAMS recorded higher frequency data on-board for post-mission analysis. The MMA downlinked real-time quasi-steady as well as higher frequency acceleration data, which was provided to the investigators. The Principal Investigator Microgravity Services (PIMS) project at NASA LERC supports principal investigators of microgravity experiments as they evaluate the effects of varying acceleration levels on their experiments. A summary report was prepared by PIMS to furnish interested experiment investigators with a guide to evaluate the acceleration environment during STS-78, and as a means of identifying areas which require further study. The summary report provides an overview of the STS-78 mission, describes the accelerometer systems flown on this mission, discusses some specific analyses of the accelerometer data in relation to the various activities which occurred during the mission, and presents plots resulting from these analyses as a snapshot of the environment during the mission. Numerous activities occurred during the STS-78 mission that are of interest to the low-gravity community. Specific activities of interest during this mission were crew exercise, radiator deployment, Vernier Reaction

  17. Development of a Wireless Displacement Measurement System Using Acceleration Responses

    PubMed Central

    Park, Jong-Woong; Sim, Sung-Han; Jung, Hyung-Jo; Spencer, Billie F.

    2013-01-01

    Displacement measurements are useful information for various engineering applications such as structural health monitoring (SHM), earthquake engineering and system identification. Most existing displacement measurement methods are costly, labor-intensive, and have difficulties particularly when applying to full-scale civil structures because the methods require stationary reference points. Indirect estimation methods converting acceleration to displacement can be a good alternative as acceleration transducers are generally cost-effective, easy to install, and have low noise. However, the application of acceleration-based methods to full-scale civil structures such as long span bridges is challenging due to the need to install cables to connect the sensors to a base station. This article proposes a low-cost wireless displacement measurement system using acceleration. Developed with smart sensors that are low-cost, wireless, and capable of on-board computation, the wireless displacement measurement system has significant potential to impact many applications that need displacement information at multiple locations of a structure. The system implements an FIR-filter type displacement estimation algorithm that can remove low frequency drifts typically caused by numerical integration of discrete acceleration signals. To verify the accuracy and feasibility of the proposed system, laboratory tests are carried out using a shaking table and on a three storey shear building model, experimentally confirming the effectiveness of the proposed system. PMID:23881123

  18. Knowledge engineering for PACES, the particle accelerator control expert system

    NASA Astrophysics Data System (ADS)

    Lind, P. C.; Poehlman, W. F. S.; Stark, J. W.; Cousins, T.

    1992-04-01

    The KN-3000 used at Defense Research Establishment Ottawa is a Van de Graaff particle accelerator employed primarily to produce monoenergetic neutrons for calibrating radiation detectors. To provide training and assistance for new operators, it was decided to develop an expert system for accelerator operation. Knowledge engineering aspects of the expert system are reviewed. Two important issues are involved: the need to encapsulate expert knowledge into the system in a form that facilitates automatic accelerator operation and to partition the system so that time-consuming inferencing is minimized in favor of faster, more algorithmic control. It is seen that accelerator control will require fast, narrowminded decision making for rapid fine tuning, but slower and broader reasoning for machine startup, shutdown, fault diagnosis, and correction. It is also important to render the knowledge base in a form conducive to operator training. A promising form of the expert system involves a hybrid system in which high level reasoning is performed on the host machine that interacts with the user, while an embedded controller employs neural networks for fast but limited adjustment of accelerator performance. This partitioning of duty facilitates a hierarchical chain of command yielding an effective mixture of speed and reasoning ability.

  19. ACCELERATORS: Timing system of HIRFL-CSR

    NASA Astrophysics Data System (ADS)

    Dong, Jin-Mei; Yuan, You-Jin; Qiao, Wei-Min; Jing, Lan; Zhang, Wei

    2009-05-01

    The national science project HIRFL-CSR has recently been officially accepted. As a cyclotron and synchrotron complex, it puts some particularly high demands on the control system. There are hundreds of pieces of equipment that need to be synchronized. An integrated timing control system is built to meet these demands. The output rate and the accuracy of the controller are 16 bit/μs. The accuracy of the time delay reaches 40 ns. The timing control system is based on a typical event distribution system, which adopts the new event generation and the distribution scheme. The scheme of the timing control system with innovation points, the architecture and the implemented method are presented in the paper.

  20. Acceleration display system for aircraft zero-gravity research

    NASA Technical Reports Server (NTRS)

    Millis, Marc G.

    1987-01-01

    The features, design, calibration, and testing of Lewis Research Center's acceleration display system for aircraft zero-gravity research are described. Specific circuit schematics and system specifications are included as well as representative data traces from flown trajectories. Other observations learned from developing and using this system are mentioned where appropriate. The system, now a permanent part of the Lewis Learjet zero-gravity program, provides legible, concise, and necessary guidance information enabling pilots to routinely fly accurate zero-gravity trajectories. Regular use of this system resulted in improvements of the Learjet zero-gravity flight techniques, including a technique to minimize later accelerations. Lewis Gates Learjet trajectory data show that accelerations can be reliably sustained within 0.01 g for 5 consecutive seconds, within 0.02 g for 7 consecutive seconds, and within 0.04 g for up to 20 second. Lewis followed the past practices of acceleration measurement, yet focussed on the acceleration displays. Refinements based on flight experience included evolving the ranges, resolutions, and frequency responses to fit the pilot and the Learjet responses.

  1. Small Accelerators for the Next Generation of BNCT Irradiation Systems

    SciTech Connect

    Kobayashi, T.; Tanaka, K.; Bengua, G.; Hoshi, M.; Nakagawa, Y.

    2005-01-15

    The neutron irradiation system for boron neutron capture therapy (BNCT) using compact accelerators installed at hospitals was mainly investigated for the usage of direct neutrons from near-threshold {sup 7}Li(p,n){sup 7}Be, and moderated neutrons from 2.5 MeV {sup 7}Li(p,n){sup 7}Be reactions and other reactions. This kind of system can supply the medical doctors and patients with convenience to carry out BNCT in hospitals. The accelerator system would be regarded as the next-generation of BNCT in the near future.

  2. COMMISSIONING OF THE SPALLATION NEUTRON SOURCE ACCELERATOR SYSTEMS

    SciTech Connect

    Plum, Michael A

    2007-01-01

    The Spallation Neutron Source accelerator complex consists of a 2.5 MeV H- front-end injector system, a 186 MeV normal-conducting linear accelerator, a 1 GeV superconducting linear accelerator, an accumulator ring, and associated beam transport lines. The linac was commissioned in five discrete runs, starting in 2002 and completed in 2005. The accumulator ring and associated beam transport lines were commissioned in two runs from January to April 2006. With the completed commissioning of the SNS accelerator, the facility has begun initial low-power operations. In the course of beam commissioning, most beam performance parameters and beam intensity goals have been achieved at low duty factor. A number of beam dynamics measurements have been performed, including emittance evolution, transverse coupling in the ring, beam instability thresholds, and beam distributions on the target. The commissioning results, achieved beam performance and initial operating experience of the SNS will be discussed

  3. dc power system for deuteron accelerator

    SciTech Connect

    Creek, K.O.; Liska, D.J.

    1981-01-01

    The Fusion Materials Irradiation Test (FMIT) Facility dc power system provides excitation current for all linac and High-Energy Beam Transport (HEBT) quadrupole and bending magnets, excitation for horizontal and vertical beam steering, and current-bypass shunts.

  4. Emerging standards with application to accelerator safety systems

    SciTech Connect

    Mahoney, K.L.; Robertson, H.P.

    1997-08-01

    This paper addresses international standards which can be applied to the requirements for accelerator personnel safety systems. Particular emphasis is given to standards which specify requirements for safety interlock systems which employ programmable electronic subsystems. The work draws on methodologies currently under development for the medical, process control, and nuclear industries.

  5. Versatile Low Level RF System For Linear Accelerators

    SciTech Connect

    Potter, James M.

    2011-06-01

    The Low Level RF (LLRF) system is the source of all of the rf signals required for an rf linear accelerator. These signals are amplified to drive accelerator and buncher cavities. It can even provide the synchronizing signal for the rf power for a synchrotron. The use of Direct Digital Synthesis (DDS) techniques results in a versatile system that can provide multiple coherent signals at the same or different frequencies with adjustable amplitudes and phase relations. Pulsing the DDS allows rf switching with an essentially infinite on/off ratio. The LLRF system includes a versatile phase detector that allows phase-locking the rf frequency to a cavity at any phase angle over the full 360 deg. range. With the use of stepper motor driven slug tuners multiple cavity resonant frequencies can be phase locked to the rf source frequency. No external phase shifters are required and there is no feedback loop phase setup required. All that is needed is to turn the frequency feedback on. The use of Digital Signal Processing (DSP) allows amplitude and phase control over the entire rf pulse. This paper describes the basic principles of a LLRF system that has been used for both proton accelerators and electron accelerators, including multiple tank accelerators, sub-harmonic and fundamental bunchers, and synchrotrons.

  6. Versatile Low Level RF System For Linear Accelerators

    NASA Astrophysics Data System (ADS)

    Potter, James M.

    2011-06-01

    The Low Level RF (LLRF) system is the source of all of the rf signals required for an rf linear accelerator. These signals are amplified to drive accelerator and buncher cavities. It can even provide the synchronizing signal for the rf power for a synchrotron. The use of Direct Digital Synthesis (DDS) techniques results in a versatile system that can provide multiple coherent signals at the same or different frequencies with adjustable amplitudes and phase relations. Pulsing the DDS allows rf switching with an essentially infinite on/off ratio. The LLRF system includes a versatile phase detector that allows phase-locking the rf frequency to a cavity at any phase angle over the full 360° range. With the use of stepper motor driven slug tuners multiple cavity resonant frequencies can be phase locked to the rf source frequency. No external phase shifters are required and there is no feedback loop phase setup required. All that is needed is to turn the frequency feedback on. The use of Digital Signal Processing (DSP) allows amplitude and phase control over the entire rf pulse. This paper describes the basic principles of a LLRF system that has been used for both proton accelerators and electron accelerators, including multiple tank accelerators, sub-harmonic and fundamental bunchers, and synchrotrons.

  7. Physics design of an accelerator for an accelerator-driven subcritical system

    NASA Astrophysics Data System (ADS)

    Li, Zhihui; Cheng, Peng; Geng, Huiping; Guo, Zhen; He, Yuan; Meng, Cai; Ouyang, Huafu; Pei, Shilun; Sun, Biao; Sun, Jilei; Tang, Jingyu; Yan, Fang; Yang, Yao; Zhang, Chuang; Yang, Zheng

    2013-08-01

    An accelerator-driven subcritical system (ADS) program was launched in China in 2011, which aims to design and build an ADS demonstration facility with the capability of more than 1000 MW thermal power in multiple phases lasting about 20 years. The driver linac is defined to be 1.5 GeV in energy, 10 mA in current and in cw operation mode. To meet the extremely high reliability and availability, the linac is designed with much installed margin and fault tolerance, including hot-spare injectors and local compensation method for key element failures. The accelerator complex consists of two parallel 10-MeV injectors, a joint medium-energy beam transport line, a main linac, and a high-energy beam transport line. The superconducting acceleration structures are employed except for the radio frequency quadrupole accelerators (RFQs) which are at room temperature. The general design considerations and the beam dynamics design of the driver linac complex are presented here.

  8. Space Launch System Accelerated Booster Development Cycle

    NASA Technical Reports Server (NTRS)

    Arockiam, Nicole; Whittecar, William; Edwards, Stephen

    2012-01-01

    With the retirement of the Space Shuttle, NASA is seeking to reinvigorate the national space program and recapture the public s interest in human space exploration by developing missions to the Moon, near-earth asteroids, Lagrange points, Mars, and beyond. The would-be successor to the Space Shuttle, NASA s Constellation Program, planned to take humans back to the Moon by 2020, but due to budgetary constraints was cancelled in 2010 in search of a more "affordable, sustainable, and realistic" concept2. Following a number of studies, the much anticipated Space Launch System (SLS) was unveiled in September of 2011. The SLS core architecture consists of a cryogenic first stage with five Space Shuttle Main Engines (SSMEs), and a cryogenic second stage using a new J-2X engine3. The baseline configuration employs two 5-segment solid rocket boosters to achieve a 70 metric ton payload capability, but a new, more capable booster system will be required to attain the goal of 130 metric tons to orbit. To this end, NASA s Marshall Space Flight Center recently released a NASA Research Announcement (NRA) entitled "Space Launch System (SLS) Advanced Booster Engineering Demonstration and/or Risk Reduction." The increased emphasis on affordability is evident in the language used in the NRA, which is focused on risk reduction "leading to an affordable Advanced Booster that meets the evolved capabilities of SLS" and "enabling competition" to "enhance SLS affordability. The purpose of the work presented in this paper is to perform an independent assessment of the elements that make up an affordable and realistic path forward for the SLS booster system, utilizing advanced design methods and technology evaluation techniques. The goal is to identify elements that will enable a more sustainable development program by exploring the trade space of heavy lift booster systems and focusing on affordability, operability, and reliability at the system and subsystem levels5. For this study

  9. The String of Pearls

    2006-07-01

    A team of collaborators within the Southwest Regional Partnership (SRP) on Carbon Sequestration developed an interactive software tool to help facilitate discussions involving the science, engineering, economic and policy considerations for a carbon sequestration pilot project. This model illustrates the "String of Pearls" algorithm used to develop a hypothetical carbon dioxide (CO2) transportation network in sequence with existing infrastructure. The "String of Pearls" model can assess geological sink combinations according to their distance from themore » point source (e.g., power plant), relative size (to maintain a useful fill lifetime for a project), relative distance from existing CO2 transportation infrastructure, and other salient project attributes. The results indicate that the cost to capture CO2 at point sources (e.g. power plants) is the largest component of the overall CO2 capture, transportation and storage system's initial cost estimate. The "String of Pearls" Integrated Assessment model can help planners assess these issues using an integrated, systems view when deciding where to develop future carbon sequestration pilot projects. Likely users of this model include partners within the SRP, other regional partnerships and interested individuals, and private industry interested in carbon sequestration systems. The model seeks to improve understanding of the economic viability and emission trade-offs associated with all stages of carbone sequestration systems analysis.« less

  10. The String of Pearls

    SciTech Connect

    Borns, David J.; Kobos, Peter H.; Malczynski, Leonard A.

    2006-07-01

    A team of collaborators within the Southwest Regional Partnership (SRP) on Carbon Sequestration developed an interactive software tool to help facilitate discussions involving the science, engineering, economic and policy considerations for a carbon sequestration pilot project. This model illustrates the "String of Pearls" algorithm used to develop a hypothetical carbon dioxide (CO2) transportation network in sequence with existing infrastructure. The "String of Pearls" model can assess geological sink combinations according to their distance from the point source (e.g., power plant), relative size (to maintain a useful fill lifetime for a project), relative distance from existing CO2 transportation infrastructure, and other salient project attributes. The results indicate that the cost to capture CO2 at point sources (e.g. power plants) is the largest component of the overall CO2 capture, transportation and storage system's initial cost estimate. The "String of Pearls" Integrated Assessment model can help planners assess these issues using an integrated, systems view when deciding where to develop future carbon sequestration pilot projects. Likely users of this model include partners within the SRP, other regional partnerships and interested individuals, and private industry interested in carbon sequestration systems. The model seeks to improve understanding of the economic viability and emission trade-offs associated with all stages of carbone sequestration systems analysis.

  11. Accelerator-Feasible N-Body Nonlinear Integrable System

    SciTech Connect

    Danilov, V.; Nagaitsev, S.

    2014-12-23

    Nonlinear N-body integrable Hamiltonian systems, where N is an arbitrary number, attract the attention of mathematical physicists for the last several decades, following the discovery of some number of these systems. This paper presents a new integrable system, which can be realized in facilities such as particle accelerators. This feature makes it more attractive than many of the previous such systems with singular or unphysical forces.

  12. Constraint Reasoning Over Strings

    NASA Technical Reports Server (NTRS)

    Koga, Dennis (Technical Monitor); Golden, Keith; Pang, Wanlin

    2003-01-01

    This paper discusses an approach to representing and reasoning about constraints over strings. We discuss how many string domains can often be concisely represented using regular languages, and how constraints over strings, and domain operations on sets of strings, can be carried out using this representation.

  13. Evidence for string substructure

    SciTech Connect

    Bergman, O.

    1996-06-01

    The author argues that the behavior of string theory at high temperature and high longitudinal boosts, combined with the emergence of p-branes as necessary ingredients in various string dualities, point to a possible reformulation of strings, as well as p-branes, as composites of bits. He reviews the string-bit models, and suggests generalizations to incorporate p-branes.

  14. Overview of the IBA accelerator-based BNCT system.

    PubMed

    Forton, E; Stichelbaut, F; Cambriani, A; Kleeven, W; Ahlback, J; Jongen, Y

    2009-07-01

    During the last few years, IBA started the development of an accelerator-based BNCT system. The accelerator is a Dynamitron built by RDI in USA and will produce a 20 mA proton beam at 2.8 MeV. Neutrons will be produced by the (7)Li(p,n)(7)Be nuclear reaction using a thin lithium target. The neutron energy spectrum will be tailored using a beam shaping assembly. This overview presents the current status of the system: after a description of every component, some design issues, solutions and experimental tests will be discussed.

  15. An expert system for tuning particle-beam accelerators

    SciTech Connect

    Lager, D.L.; Brand, H.R.; Maurer, W.J.; Searfus, R.M.; Hernandez, J.E.

    1989-01-12

    We have developed a proof-of-concept prototype of an expert system for tuning particle beam accelerators. It is designed to function as an intelligent assistant for an operator. In its present form it implements the strategies and reasoning followed by the operator for steering through the beam transport section of the Advanced Test Accelerator at Lawrence Livermore Laboratory's Site 300. The system is implemented in the language LISP using the Artificial Intelligence concepts of frames, daemons, and a representation we developed called a Monitored Decision Script. 4 refs., 5 figs.

  16. An Expert System For Tuning Particle-Beam Accelerators

    NASA Astrophysics Data System (ADS)

    Lager, Darrel L.; Brand, Hal R.; Maurer, William J.; Searfus, Robert M.; Hernandez, Jose E.

    1989-03-01

    We have developed a proof-of-concept prototype of an expert system for tuning particle beam accelerators. It is designed to function as an intelligent assistant for an operator. In its present form it implements the strategies and reasoning followed by the operator for steering through the beam transport section of the Advanced Test Accelerator at Lawrence Livermore Laboratory's Site 300. The system is implemented in the language LISP using the Artificial Intelligence concepts of frames, daemons, and a representation we developed called a Monitored Decision Script.

  17. Design of a ram accelerator mass launch system

    NASA Technical Reports Server (NTRS)

    Aarnio, Michael; Armerding, Calvin; Berschauer, Andrew; Christofferson, Erik; Clement, Paul; Gohd, Robin; Neely, Bret; Reed, David; Rodriguez, Carlos; Swanstrom, Fredrick

    1988-01-01

    The ram accelerator mass launch system has been proposed to greatly reduce the costs of placing acceleration-insensitive payloads into low earth orbit. The ram accelerator is a chemically propelled, impulsive mass launch system capable of efficiently accelerating relatively large masses from velocities of 0.7 km/sec to 10 km/sec. The principles of propulsion are based on those of a conventional supersonic air-breathing ramjet; however the device operates in a somewhat different manner. The payload carrying vehicle resembles the center-body of the ramjet and accelerates through a stationary tube which acts as the outer cowling. The tube is filled with premixed gaseous fuel and oxidizer mixtures that burn in the vicinity of the vehicle's base, producing a thrust which accelerates the vehicle through the tube. This study examines the requirement for placing a 2000 kg vehicle into a 500 km circular orbit with a minimum amount of on-board rocket propellant for orbital maneuvers. The goal is to achieve a 50 pct payload mass fraction. The proposed design requirements have several self-imposed constraints that define the vehicle and tube configurations. Structural considerations on the vehicle and tube wall dictate an upper acceleration limit of 1000 g's and a tube inside diameter of 1.0 m. In-tube propulsive requirements and vehicle structural constraints result in a vehicle diameter of 0.76 m, a total length of 7.5 m and a nose-cone half angle of 7 degrees. An ablating nose-cone constructed from carbon-carbon composite serves as the thermal protection mechanism for atmospheric transit.

  18. String driven inflation

    SciTech Connect

    Turok, N.

    1987-11-01

    It is argued that, in fundamental string theories, as one traces the universe back in time a point is reached when the expansion rate is so fast that the rate of string creation due to quantum effects balances the dilution of the string density due to the expansion. One is therefore led into a phase of constant string density and an exponentially expanding universe. Fundamental strings therefore seem to lead naturally to inflation. 17 refs., 1 fig.

  19. String-driven inflation

    NASA Technical Reports Server (NTRS)

    Turok, Neil

    1988-01-01

    It is argued that, in fundamental string theories, as one traces the universe back in time a point is reached when the expansion rate is so fast that the rate of string creation due to quantum effects balances the dilution of the string density due to the expansion. One is therefore led into a phase of constant string density and an exponentially expanding universe. Fundamental strings therefore seem to lead naturally to inflation.

  20. The exact correspondence between conserved quantities of a periodic box-ball system and string solutions of the Bethe ansatz equations

    NASA Astrophysics Data System (ADS)

    Mada, Jun; Idzumi, Makoto; Tokihiro, Tetsuji

    2006-05-01

    We investigate the link between a periodic box-ball system (PBBS) and a solvable lattice model. Introducing a PBBS with an integer parameter corresponding to the dimensionality of the auxiliary space for the lattice model, we prove an important relationship between the conserved quantities of states of the PBBS and eigenvectors constructed through the string hypothesis.

  1. The exact correspondence between conserved quantities of a periodic box-ball system and string solutions of the Bethe ansatz equations

    SciTech Connect

    Mada, Jun; Idzumi, Makoto; Tokihiro, Tetsuji

    2006-05-15

    We investigate the link between a periodic box-ball system (PBBS) and a solvable lattice model. Introducing a PBBS with an integer parameter corresponding to the dimensionality of the auxiliary space for the lattice model, we prove an important relationship between the conserved quantities of states of the PBBS and eigenvectors constructed through the string hypothesis.

  2. String axiverse

    SciTech Connect

    Arvanitaki, Asimina; Dimopoulos, Savas; Dubovsky, Sergei; Kaloper, Nemanja; March-Russell, John

    2010-06-15

    String theory suggests the simultaneous presence of many ultralight axions, possibly populating each decade of mass down to the Hubble scale 10{sup -33} eV. Conversely the presence of such a plenitude of axions (an axiverse) would be evidence for string theory, since it arises due to the topological complexity of the extra-dimensional manifold and is ad hoc in a theory with just the four familiar dimensions. We investigate how several upcoming astrophysical experiments will be observationally exploring the possible existence of such axions over a vast mass range from 10{sup -33} eV to 10{sup -10} eV. Axions with masses between 10{sup -33} eV to 10{sup -28} eV can cause a rotation of the cosmic microwave background polarization that is constant throughout the sky. The predicted rotation angle is independent of the scale of inflation and the axion decay constant, and is of order {alpha}{approx}1/137-within reach of the just launched Planck satellite. Axions in the mass range 10{sup -28} eV to 10{sup -18} eV give rise to multiple steps in the matter power spectrum, providing us with a snapshot of the axiverse that will be probed by galaxy surveys-such as BOSS, and 21 cm line tomography. Axions in the mass range 10{sup -22} eV to 10{sup -10} eV can affect the dynamics and gravitational wave emission of rapidly rotating astrophysical black holes through the Penrose superradiance process. When the axion Compton wavelength is of order of the black hole size, the axions develop superradiant atomic bound states around the black hole nucleus. Their occupation number grows exponentially by extracting rotational energy and angular momentum from the ergosphere, culminating in a rotating Bose-Einstein axion condensate emitting gravitational waves. For black holes lighter than {approx}10{sup 7} solar masses accretion cannot replenish the spin of the black hole, creating mass gaps in the spectrum of rapidly rotating black holes that diagnose the presence of destabilizing axions

  3. Nuclear data needs for accelerator-driven transmutation systems

    SciTech Connect

    Arthur, E.D.; Wilson, W.B.; Young, P.G.

    1994-07-01

    The possibilities of several new technologies based on use of intense, medium-energy proton accelerators are being investigated at Los Alamos National Laboratory. The potential new areas include destruction of long-lived components of nuclear waste, plutonium burning, energy production, and production of tritium. The design, assessment, and safety analysis of potential facilities involves the understanding of complex combinations of nuclear processes, which in turn places new requirements on nuclear data that transcend the traditional needs of the fission and fusion reactor communities. In this paper an assessment of the nuclear data needs for systems currently being considered in the Los Alamos Accelerator-Driven Transmutation Technologies program is given.

  4. Ram accelerator direct space launch system - New concepts

    NASA Technical Reports Server (NTRS)

    Bogdanoff, David W.

    1992-01-01

    The ram accelerator, a chemically driven ramjet-in-tube device is a new option for direct launch of acceleration-insensitive payloads into earth orbit. The projectile is the centerbody of a ramjet and travels through a tube filled with a premixed fuel-oxidizer mixture. The tube acts as the cowl of the ramjet. A number of new concepts for a ram accelerator space launch system are presented. The velocity and acceleration capabilities of a number of ram accelerator drive modes, including several new modes, are given. Passive (fin) stabilization during atmospheric transit is investigated and found to be promising. Gasdynamic heating in-tube and during atmospheric transit is studied; the former is found to be severe, but may be alleviated by the selection of the most suitable drive modes, transpiration cooling, or a hydrogen gas core in the launch tube. To place the payload in earth orbit, scenarios using one impulse and three impulses (with an aeropass) and a new scenario involving an auxiliary vehicle are studied. The auxiliary vehicle scenario is found to be competitive regarding payload, and requires a much simpler projectile, but has the disadvantage of requiring the auxiliary vehicle.

  5. High Power Cyclotrons for Accelerator Driven System (ADS)

    NASA Astrophysics Data System (ADS)

    Calabretta, Luciano

    2012-03-01

    We present an accelerator module based on a injector cyclotron and a Superconducting Ring Cyclotron (SRC) able to accelerate H2+ molecules. H2+ molecules are extracted from the SRC stripping the binding electron by a thin carbon foil. The SRC will be able to deliver proton beam with maximum energy of 800 MeV and a maximum power of 8 MW. This module is forecasted for the DAEdALUS (Decay At rest Experiment for δcp At Laboratory for Underground Science) experiment, which is a neutrino experiment proposed by groups of MIT and Columbia University. Extensive beam dynamics studies have been carrying out in the last two years and proved the feasibility of the design. The use of H2+ molecules beam has three main advantages: 1) it reduces the space charge effects, 2) because of stripping extraction, it simplifies the extraction process w.r.t. single turn extraction and 3) we can extract more than one beam out of one SRC. A suitable upgraded version of the cyclotron module able to deliver up to 10MW beam is proposed to drive ADS. The accelerator system which is presented, consists of having three accelerators modules. Each SRC is equipped with two extraction systems delivering two beams each one with a power up to 5 MW. Each accelerator module, feeds both the two reactors at the same time. The three accelerators modules assure to maintain continuity in functioning of the two reactors. In normal operation, all the three accelerators module will deliver 6.6 MW each one, just in case one of the three accelerator module will be off, due to a fault or maintenance, the other two modules are pushed at maximum power of 10 MW. The superconducting magnetic sector of the SRC, as well as the normal conducting sector of the injector cyclotron, is calculated with the TOSCA module of OPERA3D. Here the main features of the injector cyclotron, of the SRC and the beam dynamic along the cyclotrons are presented.

  6. The Awful Truth About Zero-Gravity: Space Acceleration Measurement System; Orbital Acceleration Research Experiment

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Earth's gravity holds the Shuttle in orbit, as it does satellites and the Moon. The apparent weightlessness experienced by astronauts and experiments on the Shuttle is a balancing act, the result of free-fall, or continuously falling around Earth. An easy way to visualize what is happening is with a thought experiment that Sir Isaac Newton did in 1686. Newton envisioned a mountain extending above Earth's atmosphere so that friction with the air would be eliminated. He imagined a cannon atop the mountain and aimed parallel to the ground. Firing the cannon propels the cannonball forward. At the same time, Earth's gravity pulls the cannonball down to the surface and eventual impact. Newton visualized using enough powder to just balance gravity so the cannonball would circle the Earth. Like the cannonball, objects orbiting Earth are in continuous free-fall, and it appears that gravity has been eliminated. Yet, that appearance is deceiving. Activities aboard the Shuttle generate a range of accelerations that have effects similar to those of gravity. The crew works and exercises. The main data relay antenna quivers 17 times per second to prevent 'stiction,' where parts stick then release with a jerk. Cooling pumps, air fans, and other systems add vibration. And traces of Earth's atmosphere, even 200 miles up, drag on the Shuttle. While imperceptible to us, these vibrations can have a profound impact on the commercial research and scientific experiments aboard the Shuttle. Measuring these forces is necessary so that researchers and scientists can see what may have affected their experiments when analyzing data. On STS-107 this service is provided by the Space Acceleration Measurement System for Free Flyers (SAMS-FF) and the Orbital Acceleration Research Experiment (OARE). Precision data from these two instruments will help scientists analyze data from their experiments and eliminate outside influences from the phenomena they are studying during the mission.

  7. Accelerate!

    PubMed

    Kotter, John P

    2012-11-01

    The old ways of setting and implementing strategy are failing us, writes the author of Leading Change, in part because we can no longer keep up with the pace of change. Organizational leaders are torn between trying to stay ahead of increasingly fierce competition and needing to deliver this year's results. Although traditional hierarchies and managerial processes--the components of a company's "operating system"--can meet the daily demands of running an enterprise, they are rarely equipped to identify important hazards quickly, formulate creative strategic initiatives nimbly, and implement them speedily. The solution Kotter offers is a second system--an agile, networklike structure--that operates in concert with the first to create a dual operating system. In such a system the hierarchy can hand off the pursuit of big strategic initiatives to the strategy network, freeing itself to focus on incremental changes to improve efficiency. The network is populated by employees from all levels of the organization, giving it organizational knowledge, relationships, credibility, and influence. It can Liberate information from silos with ease. It has a dynamic structure free of bureaucratic layers, permitting a level of individualism, creativity, and innovation beyond the reach of any hierarchy. The network's core is a guiding coalition that represents each level and department in the hierarchy, with a broad range of skills. Its drivers are members of a "volunteer army" who are energized by and committed to the coalition's vividly formulated, high-stakes vision and strategy. Kotter has helped eight organizations, public and private, build dual operating systems over the past three years. He predicts that such systems will lead to long-term success in the 21st century--for shareholders, customers, employees, and companies themselves. PMID:23155997

  8. Accelerate!

    PubMed

    Kotter, John P

    2012-11-01

    The old ways of setting and implementing strategy are failing us, writes the author of Leading Change, in part because we can no longer keep up with the pace of change. Organizational leaders are torn between trying to stay ahead of increasingly fierce competition and needing to deliver this year's results. Although traditional hierarchies and managerial processes--the components of a company's "operating system"--can meet the daily demands of running an enterprise, they are rarely equipped to identify important hazards quickly, formulate creative strategic initiatives nimbly, and implement them speedily. The solution Kotter offers is a second system--an agile, networklike structure--that operates in concert with the first to create a dual operating system. In such a system the hierarchy can hand off the pursuit of big strategic initiatives to the strategy network, freeing itself to focus on incremental changes to improve efficiency. The network is populated by employees from all levels of the organization, giving it organizational knowledge, relationships, credibility, and influence. It can Liberate information from silos with ease. It has a dynamic structure free of bureaucratic layers, permitting a level of individualism, creativity, and innovation beyond the reach of any hierarchy. The network's core is a guiding coalition that represents each level and department in the hierarchy, with a broad range of skills. Its drivers are members of a "volunteer army" who are energized by and committed to the coalition's vividly formulated, high-stakes vision and strategy. Kotter has helped eight organizations, public and private, build dual operating systems over the past three years. He predicts that such systems will lead to long-term success in the 21st century--for shareholders, customers, employees, and companies themselves.

  9. Racetrack inflation with matter fields and cosmic strings

    SciTech Connect

    Brax, Ph; De Bruck, C van; Davis, A C; Davis, S C; Jeannerot, R; Postma, M E-mail: c.vandebruck@shef.ac.uk E-mail: S.C.Davis@damtp.cam.ac.uk E-mail: postma@mail.desy.de

    2008-07-15

    We consider the coupling of racetrack inflation to matter fields as realized in the D3/D7 brane system. In particular, we investigate the possibility of cosmic string formation in this system. We find that strings can form before or at the onset of racetrack inflation is possible, but they are then inflated away. Furthermore, string formation at the end of inflation is prevented by the presence of the moduli sector. As a consequence, no strings survive racetrack inflation.

  10. Sorting Symbol Strings

    ERIC Educational Resources Information Center

    Novak, Jodie D.; Jacobs, Judith E.

    2005-01-01

    This article describes a variety of activities that ask students to identify, describe, compare, and classify symbol strings (algebraic expressions and equations). The activities use a collection of twelve symbol strings on cards. (Contains 2 figures.)

  11. Light from cosmic strings

    SciTech Connect

    Steer, Daniele A.; Vachaspati, Tanmay

    2011-02-15

    The time-dependent metric of a cosmic string leads to an effective interaction between the string and photons--the ''gravitational Aharonov-Bohm'' effect--and causes cosmic strings to emit light. We evaluate the radiation of pairs of photons from cosmic strings and find that the emission from cusps, kinks and kink-kink collisions occurs with a flat spectrum at all frequencies up to the string scale. Further, cusps emit a beam of photons, kinks emit along a curve, and the emission at a kink-kink collision is in all directions. The emission of light from cosmic strings could provide an important new observational signature of cosmic strings that is within reach of current experiments for a range of string tensions.

  12. Study on a Mechanical Semi-Active Heave Compensation System of Drill String for Use on Floating Drilling Platform

    PubMed Central

    Liu, Qingyou; Tang, Yang; Huang, Chongjun; Xie, Chong

    2015-01-01

    There are some disadvantages for existing heave compensation systems of drill string used for the Floating Drilling Platform (FDP), including high energy consumption, large and complex structure, and expensive manufacturing and maintenance costs. In view of the above, we present a streamlined mechanical semi-active heave compensation system (MSAHC) in this study. This system consists of active compensation part with the pinion and rack and passive compensation part. In order to evaluate system performance of the MSAHC, we establish its simulation model with AMEsim software. In the process of simulation, displacement of rotary hook and energy consumption is regarded as performance parameters of the system. And the change rule of two performance parameters are analyzed by changing these design parameters including gear radius of the pinion and rack, scale coefficient of PID, rotary hook load, heave height and heave period of the FDP, and accumulator volume. Then, based on the simulation results of the MSAHC system performance, we have selected out a best set of design parameters from them. Moreover, the feasibility of the design scheme of the MSAHC is effectively verified by comparison with the existing three heave compensation system. The result shows that the energy consumption of the MSAHC is lower than the active heave compensation system (AHC) and the semi-active heave compensation system (SAHC) when achieving a same compensation effect as well as the accumulator volume of MSAHC is half of the passive heave compensation system (PHC). Therefore, the new designed MSAHC not only ensure compensation effect but also lower energy consumption, and its structure is simplified by adopting the simple mechanical structure to decrease manufacturing cost, maintenance cost and floor space. PMID:26186620

  13. Study on a Mechanical Semi-Active Heave Compensation System of Drill String for Use on Floating Drilling Platform.

    PubMed

    Liu, Qingyou; Tang, Yang; Huang, Chongjun; Xie, Chong

    2015-01-01

    There are some disadvantages for existing heave compensation systems of drill string used for the Floating Drilling Platform (FDP), including high energy consumption, large and complex structure, and expensive manufacturing and maintenance costs. In view of the above, we present a streamlined mechanical semi-active heave compensation system (MSAHC) in this study. This system consists of active compensation part with the pinion and rack and passive compensation part. In order to evaluate system performance of the MSAHC, we establish its simulation model with AMEsim software. In the process of simulation, displacement of rotary hook and energy consumption is regarded as performance parameters of the system. And the change rule of two performance parameters are analyzed by changing these design parameters including gear radius of the pinion and rack, scale coefficient of PID, rotary hook load, heave height and heave period of the FDP, and accumulator volume. Then, based on the simulation results of the MSAHC system performance, we have selected out a best set of design parameters from them. Moreover, the feasibility of the design scheme of the MSAHC is effectively verified by comparison with the existing three heave compensation system. The result shows that the energy consumption of the MSAHC is lower than the active heave compensation system (AHC) and the semi-active heave compensation system (SAHC) when achieving a same compensation effect as well as the accumulator volume of MSAHC is half of the passive heave compensation system (PHC). Therefore, the new designed MSAHC not only ensure compensation effect but also lower energy consumption, and its structure is simplified by adopting the simple mechanical structure to decrease manufacturing cost, maintenance cost and floor space.

  14. Study on a Mechanical Semi-Active Heave Compensation System of Drill String for Use on Floating Drilling Platform.

    PubMed

    Liu, Qingyou; Tang, Yang; Huang, Chongjun; Xie, Chong

    2015-01-01

    There are some disadvantages for existing heave compensation systems of drill string used for the Floating Drilling Platform (FDP), including high energy consumption, large and complex structure, and expensive manufacturing and maintenance costs. In view of the above, we present a streamlined mechanical semi-active heave compensation system (MSAHC) in this study. This system consists of active compensation part with the pinion and rack and passive compensation part. In order to evaluate system performance of the MSAHC, we establish its simulation model with AMEsim software. In the process of simulation, displacement of rotary hook and energy consumption is regarded as performance parameters of the system. And the change rule of two performance parameters are analyzed by changing these design parameters including gear radius of the pinion and rack, scale coefficient of PID, rotary hook load, heave height and heave period of the FDP, and accumulator volume. Then, based on the simulation results of the MSAHC system performance, we have selected out a best set of design parameters from them. Moreover, the feasibility of the design scheme of the MSAHC is effectively verified by comparison with the existing three heave compensation system. The result shows that the energy consumption of the MSAHC is lower than the active heave compensation system (AHC) and the semi-active heave compensation system (SAHC) when achieving a same compensation effect as well as the accumulator volume of MSAHC is half of the passive heave compensation system (PHC). Therefore, the new designed MSAHC not only ensure compensation effect but also lower energy consumption, and its structure is simplified by adopting the simple mechanical structure to decrease manufacturing cost, maintenance cost and floor space. PMID:26186620

  15. Hardware-accelerated Components for Hybrid Computing Systems

    SciTech Connect

    Chavarría-Miranda, Daniel; Nieplocha, Jaroslaw; Gorton, Ian

    2008-10-31

    We present a study on the use of component technology for encapsulating platform-specific hardwareaccelerated algorithms on hybrid HPC systems. Our research shows that component technology can have significant benefits from a software engineering pointof- view to increase encapsulation, portability and reduce or eliminate platform dependence for hardwareaccelerated algorithms. As a demonstration of this concept, we discuss our experience in designing, implementing and integrating an FPGA-accelerated kernel for Polygraph, an application in computational proteomics.

  16. Quick setup of unit test for accelerator controls system

    SciTech Connect

    Fu, W.; D'Ottavio, T.; Gassner, D.; Nemesure, S.; Morris, J.

    2011-03-28

    Testing a single hardware unit of an accelerator control system often requires the setup of a program with graphical user interface. Developing a dedicated application for a specific hardware unit test could be time consuming and the application may become obsolete after the unit tests. This paper documents a methodology for quick design and setup of an interface focused on performing unit tests of accelerator equipment with minimum programming work. The method has three components. The first is a generic accelerator device object (ADO) manager which can be used to setup, store, and log testing controls parameters for any unit testing system. The second involves the design of a TAPE (Tool for Automated Procedure Execution) sequence file that specifies and implements all te testing and control logic. The sting third is the design of a PET (parameter editing tool) page that provides the unit tester with all the necessary control parameters required for testing. This approach has been used for testing the horizontal plane of the Stochastic Cooling Motion Control System at RHIC.

  17. Can a String's Tension Exert a Torque on a Pulley?

    ERIC Educational Resources Information Center

    Krause, Dennis E.; Sun, Yifei

    2011-01-01

    A typical textbook problem in rotational dynamics involves calculating the angular acceleration of a massive pulley due to a string, such as in the example shown in Fig. 1. The string is assumed to be massless and to move without slipping over the pulley, which is mounted on a frictionless axle. If T[subscript L] and T[subscript R] are the…

  18. [The string of Einthoven's string galvanometer].

    PubMed

    Wyers, P J

    1996-01-01

    The Dutch physiologist Willem Einthoven (1860-1927) published in 1901 his construction of a string galvanometer. With this apparatus he opened the era for electrocardiography. As the quality of his instrument largely depended on the string of the string galvanometer it is surprising to note that in his publications Einthoven never mentioned the exact way of producing the string. However, Einthoven's hand written laboratory notes are preserved at the Museum Boerhaave in Leiden. From these notes it comes clear what problems Einthoven had with the string. To get a very thin thread of quarts he first used the method of shooting the thread as was described by Boys (1887), later the blowing method of Nichols (1894). The silvering of the thread was done first chemically, later by cathode spray. In all cases premature breaking of the thread was a nuisance. Because of these failures Einthoven might have decided not to publish any details.

  19. [The string of Einthoven's string galvanometer].

    PubMed

    Wyers, P J

    1996-01-01

    The Dutch physiologist Willem Einthoven (1860-1927) published in 1901 his construction of a string galvanometer. With this apparatus he opened the era for electrocardiography. As the quality of his instrument largely depended on the string of the string galvanometer it is surprising to note that in his publications Einthoven never mentioned the exact way of producing the string. However, Einthoven's hand written laboratory notes are preserved at the Museum Boerhaave in Leiden. From these notes it comes clear what problems Einthoven had with the string. To get a very thin thread of quarts he first used the method of shooting the thread as was described by Boys (1887), later the blowing method of Nichols (1894). The silvering of the thread was done first chemically, later by cathode spray. In all cases premature breaking of the thread was a nuisance. Because of these failures Einthoven might have decided not to publish any details. PMID:11624925

  20. Ram accelerator direct launch system for space cargo

    NASA Technical Reports Server (NTRS)

    1987-01-01

    A new method of efficiently accelerating relatively large masses (up to several metric tons) to velocities of 0.6 km/sec up to 12 km/sec using chemical energy has been developed. The vehicle travels through a tube filled with a premixed gaseous fuel and oxidizer mixture. There is no propellant on-board the vehicle. The tube acts as the outer cowling of a ram jet and the energy release process travels with the vehicle. The ballistic efficiency remains high up to extremely high velocities and the acceleration can be maintained at a nearly constant level. Five modes of ram accelerator operation have been investigated; these modes differ primarily in the method of chemical heat release and the operational velocity range, and include two subsonic combustion modes (one of which involves thermally choke a combustion behind the vehicle) and three detonation drive modes. These modes of propulsion are capable of efficient acceleration in the range of 0.6-12 km/sec, although aerodynamic heating becomes severe above about 8 km/sec. Experiments carried out to date at the University of Washington up to 2 km/sec have established proof of principle of the ram accelerator concept and have shown close agreement between predicted and measured performance. A launch system capable of delivering two metric tons into low earth orbit was selected for the purposes of the present study. The preliminary analysis indicates that the overall dimensions of a restricted acceleration (less than approx. 1000 g) launch facility would require a tube 1 m in diameter, with an overall length of approximately 4 km. As in any direct launch scheme, a small on-board rocket is required to circularize the otherwise highly elliptical orbit which intersects the Earth. Various orbital insertion scenarios have been explored for the case of a 9 km/sec ram accelerator launch. These include direct insertion through a single circularization maneuver (i.e., on rocket burn), insertion involving two burns, and a

  1. Drill string enclosure

    DOEpatents

    Jorgensen, Douglas K.; Kuhns, Douglass J.; Wiersholm, Otto; Miller, Timothy A.

    1993-01-01

    The drill string enclosure consists of six component parts, including; a top bracket, an upper acrylic cylinder, an acrylic drill casing guide, a lower acrylic cylinder, a bottom bracket, and three flexible ducts. The upper acrylic cylinder is optional based upon the drill string length. The drill string enclosure allows for an efficient drill and sight operation at a hazardous waste site.

  2. Drill string enclosure

    DOEpatents

    Jorgensen, D.K.; Kuhns, D.J.; Wiersholm, O.; Miller, T.A.

    1993-03-02

    The drill string enclosure consists of six component parts, including; a top bracket, an upper acrylic cylinder, an acrylic drill casing guide, a lower acrylic cylinder, a bottom bracket, and three flexible ducts. The upper acrylic cylinder is optional based upon the drill string length. The drill string enclosure allows for an efficient drill and sight operation at a hazardous waste site.

  3. Heavy cosmic strings

    SciTech Connect

    Donaire, M.; Rajantie, A.

    2006-03-15

    We argue that cosmic strings with high winding numbers generally form in first-order gauge symmetry breaking phase transitions, and we demonstrate this using computer simulations. These strings are heavier than single-winding strings and therefore more easily observable. Their cosmological evolution may also be very different.

  4. Dynamics of Carroll strings

    NASA Astrophysics Data System (ADS)

    Cardona, Biel; Gomis, Joaquim; Pons, Josep M.

    2016-07-01

    We construct the canonical action of a Carroll string doing the Carroll limit of a canonical relativistic string. We also study the Killing symmetries of the Carroll string, which close under an infinite dimensional algebra. The tensionless limit and the Carroll p-brane action are also discussed.

  5. Nucleus from string theory

    NASA Astrophysics Data System (ADS)

    Hashimoto, Koji; Morita, Takeshi

    2011-08-01

    In generic holographic QCD, we find that baryons are bound to form a nucleus, and that its radius obeys the empirically-known mass-number (A) dependence r∝A1/3 for large A. Our result is robust, since we use only a generic property of D-brane actions in string theory. We also show that nucleons are bound completely in a finite volume. Furthermore, employing a concrete holographic model (derived by Hashimoto, Iizuka, and Yi, describing a multibaryon system in the Sakai-Sugimoto model), the nuclear radius is evaluated as O(1)×A1/3[fm], which is consistent with experiments.

  6. Inherent Safety of Fuels for Accelerator-Driven Systems

    SciTech Connect

    Eriksson, M.; Wallenius, J.; Jolkkonen, M.; Cahalan, J.E

    2005-09-15

    Transient safety characteristics of accelerator-driven systems using advanced minor actinide fuels have been investigated. Results for a molybdenum-based Ceramic-Metal (CerMet) fuel, a magnesia-based Ceramic-Ceramic fuel, and a zirconium-nitride-based fuel are reported. The focus is on the inherent safety aspects of core design. Accident analyses are carried out for the response to unprotected loss-of-flow and accelerator beam-overpower transients and coolant voiding scenarios. An attempt is made to establish basic design limits for the fuel and cladding. Maximum temperatures during transients are determined and compared with design limits. Reactivity effects associated with coolant void, fuel and structural expansion, and cladding relocation are investigated. Design studies encompass variations in lattice pitch and pin diameter. Critical mass studies are performed. The studies indicate favorable inherent safety features of the CerMet fuel. Major consideration is given to the potential threat of coolant voiding in accelerator-driven design proposals. Results for a transient test case study of a postulated steam generator tube rupture event leading to extensive coolant voiding are presented. The study underlines the importance of having a low coolant void reactivity value in a lead-bismuth system despite the high boiling temperature of the coolant. It was found that the power rise following a voiding transient increases dramatically near the critical state. The studies suggest that a reactivity margin of a few dollars in the voided state is sufficient to permit significant reactivity insertions.

  7. Cryogenic system for the MYRRHA superconducting linear accelerator

    SciTech Connect

    Chevalier, Nicolas R.; Junquera, Tomas; Thermeau, Jean-Pierre; Romão, Luis Medeiros; Vandeplassche, Dirk

    2014-01-29

    SCK⋅CEN, the Belgian Nuclear Research Centre, is designing MYRRHA, a flexible fast spectrum research reactor (80 MW{sub th}), conceived as an accelerator driven system (ADS), able to operate in sub-critical and critical modes. It contains a continuous-wave (CW) superconducting (SC) proton accelerator of 600 MeV, a spallation target and a multiplying core with MOX fuel, cooled by liquid lead-bismuth (Pb-Bi). From 17 MeV onward, the SC accelerator will consist of 48 β=0.36 spoke-loaded cavities (352 MHz), 34 β=0.47 elliptical cavities (704 MHz) and 60 β=0.65 elliptical cavities (704 MHz). We present an analysis of the thermal loads and of the optimal operating temperature of the cryogenic system. In particular, the low operating frequency of spoke cavities makes their operation in CW mode possible both at 4.2 K or at 2 K. Our analysis outlines the main factors that determine at what temperature the spoke cavities should be operated. We then present different cryogenic fluid distribution schemes, important characteristics (storage, transfer line, etc.) and the main challenges offered by MYRRHA in terms of cryogenics.

  8. Cryogenic system for the MYRRHA superconducting linear accelerator

    NASA Astrophysics Data System (ADS)

    Chevalier, Nicolas R.; Junquera, Tomas; Thermeau, Jean-Pierre; Romão, Luis Medeiros; Vandeplassche, Dirk

    2014-01-01

    SCKṡCEN, the Belgian Nuclear Research Centre, is designing MYRRHA, a flexible fast spectrum research reactor (80 MWth), conceived as an accelerator driven system (ADS), able to operate in sub-critical and critical modes. It contains a continuous-wave (CW) superconducting (SC) proton accelerator of 600 MeV, a spallation target and a multiplying core with MOX fuel, cooled by liquid lead-bismuth (Pb-Bi). From 17 MeV onward, the SC accelerator will consist of 48 β=0.36 spoke-loaded cavities (352 MHz), 34 β=0.47 elliptical cavities (704 MHz) and 60 β=0.65 elliptical cavities (704 MHz). We present an analysis of the thermal loads and of the optimal operating temperature of the cryogenic system. In particular, the low operating frequency of spoke cavities makes their operation in CW mode possible both at 4.2 K or at 2 K. Our analysis outlines the main factors that determine at what temperature the spoke cavities should be operated. We then present different cryogenic fluid distribution schemes, important characteristics (storage, transfer line, etc.) and the main challenges offered by MYRRHA in terms of cryogenics.

  9. Comparing current cluster, massively parallel, and accelerated systems

    SciTech Connect

    Barker, Kevin J; Davis, Kei; Hoisie, Adolfy; Kerbyson, Darren J; Pakin, Scott; Lang, Mike; Sancho Pitarch, Jose C

    2010-01-01

    Currently there is large architectural diversity in high perfonnance computing systems. They include 'commodity' cluster systems that optimize per-node performance for small jobs, massively parallel processors (MPPs) that optimize aggregate perfonnance for large jobs, and accelerated systems that optimize both per-node and aggregate performance but only for applications custom-designed to take advantage of such systems. Because of these dissimilarities, meaningful comparisons of achievable performance are not straightforward. In this work we utilize a methodology that combines both empirical analysis and performance modeling to compare clusters (represented by a 4,352-core IB cluster), MPPs (represented by a 147,456-core BG/P), and accelerated systems (represented by the 129,600-core Roadrunner) across a workload of four applications. Strengths of our approach include the ability to compare architectures - as opposed to specific implementations of an architecture - attribute each application's performance bottlenecks to characteristics unique to each system, and to explore performance scenarios in advance of their availability for measurement. Our analysis illustrates that application performance is essentially unrelated to relative peak performance but that application performance can be both predicted and explained using modeling.

  10. An Integrated Enterprise Accelerator Database for the SLC Control System

    SciTech Connect

    Lahey, Terri E

    2002-08-07

    Since its inception in the early 1980's, the SLC Control System has been driven by a highly structured memory-resident real-time database. While efficient, its rigid structure and file-based sources makes it difficult to maintain and extract relevant information. The goal of transforming the sources for this database into a relational form is to enable it to be part of a Control System Enterprise Database that is an integrated central repository for SLC accelerator device and Control System data with links to other associated databases. We have taken the concepts developed for the NLC Enterprise Database and used them to create and load a relational model of the online SLC Control System database. This database contains data and structure to allow querying and reporting on beamline devices, their associations and parameters. In the future this will be extended to allow generation of EPICS and SLC database files, setup of applications and links to other databases such as accelerator maintenance, archive data, financial and personnel records, cabling information, documentation etc. The database is implemented using Oracle 8i. In the short term it will be updated daily in batch from the online SLC database. In the longer term, it will serve as the primary source for Control System static data, an R&D platform for the NLC, and contribute to SLC Control System operations.

  11. Design of a Ram Accelerator mass launch system

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The Ram Accelerator, a chemically propelled, impulsive mass launch system, is presented as a viable concept for directly launching acceleration-insensitive payloads into low Earth orbit. The principles of propulsion are based on those of an airbreathing supersonic ramjet. The payload vehicle acts as the ramjet centerbody and travels through a fixed launch tube that acts as the ramjet outer cowling. The launch tube is filled with premixed gaseous fuel and oxidizer mixtures that combust at the base of the vehicle and produce thrust. Two modes of in-tube propulsion involving ramjet cycles are used in sequence to accelerate the vehicle from 0.7 km/sec to 9 km/sec. Requirements for placing a 2000 kg vehicle into a 500-km circular orbit, with a minimum amount of onboard rocket propellant for orbital maneuvers, are examined. It is shown that in-tube propulsion requirements dictate a launch tube length of 5.1 km to achieve an exit velocity of 9 km/sec, with peak accelerations not to exceed 1000 g's. Aerodynamic heating due to atmospheric transit requires minimal ablative protection and the vehicle retains a large percentage of its exit velocity. An indirect orbital insertion maneuver with aerobraking and two apogee burns is examined to minimize the required onboard propellant mass. An appropriate onboard propulsion system design to perform the required orbital maneuvers with minimum mass requirements is also determined. The structural designs of both the launch tube and the payload vehicle are examined using simple structural and finite element analysis for various materials.

  12. Damage detection based on acceleration data using artificial immune system

    NASA Astrophysics Data System (ADS)

    Chartier, Sandra; Mita, Akira

    2009-03-01

    Nowadays, Structural Health Monitoring (SHM) is essential in order to prevent damages occurrence in civil structures. This is a particularly important issue as the number of aged structures is increasing. Damage detection algorithms are often based on changes in the modal properties like natural frequencies, modal shapes and modal damping. In this paper, damage detection is completed by using Artificial Immune System (AIS) theory directly on acceleration data. Inspired from the biological immune system, AIS is composed of several models like negative selection which has a great potential for this study. The negative selection process relies on the fact that T-cells, after their maturation, are sensitive to non self cells and can not detect self cells. Acceleration data were provided by using the numerical model of a 3-story frame structure. Damages were introduced, at particular times, by reduction of story's stiffness. Based on these acceleration data, undamaged data (equivalent to self data) and damaged data (equivalent to non self data) can be obtained and represented in the Hamming shape-space with a binary representation. From the undamaged encoded data, detectors (equivalent to T-cells) are derived and are able to detect damaged encoded data really efficiently by using the rcontiguous bits matching rule. Indeed, more than 95% of detection can be reached when efficient combinations of parameters are used. According to the number of detected data, the localization of damages can even be determined by using the differences between story's relative accelerations. Thus, the difference which presents the highest detection rate, generally up to 89%, is directly linked to the location of damage.

  13. Dilatonic global strings

    NASA Astrophysics Data System (ADS)

    Dando, Owen; Gregory, Ruth

    1998-07-01

    We examine the field equations of a self-gravitating global string in low energy superstring gravity, allowing for an arbitrary coupling of the global string to the dilaton. Massive and massless dilatons are considered. For the massive dilaton the spacetime is similar to the recently discovered non-singular time-dependent Einstein self-gravitating global string, but the massless dilaton generically gives a singular spacetime, even allowing for time dependence. We also demonstrate a time-dependent non-singular string-antistring configuration, in which the string pair causes a compactification of two of the spatial dimensions, albeit on a very large scale.

  14. Buckling and dynamic analysis of drill strings for core sampling

    SciTech Connect

    Ziada, H.H., Westinghouse Hanford

    1996-05-15

    This supporting document presents buckling and dynamic stability analyses of the drill strings used for core sampling. The results of the drill string analyses provide limiting operating axial loads and rotational speeds to prevent drill string failure, instability and drill bit overheating during core sampling. The recommended loads and speeds provide controls necessary for Tank Waste Remediation System (TWRS) programmatic field operations.

  15. Mechanical performance of fiberglass sucker-rod strings

    SciTech Connect

    Tripp, H.A.

    1988-08-01

    The natural frequencies of fiberglass sucker-rod strings can be calculated by treating the rod strings as modified spring/mass vibration systems. The ratio of the pumping-unit operating speed to the rod-string natural frequency can then be used as a basis for understanding fiberglass-rod performance and for predicting downhole pump stroke lengths.

  16. Large high-vacuum systems for CERN accelerators

    NASA Astrophysics Data System (ADS)

    Strubin, P.

    2008-05-01

    CERN operated over the more than 50 years of its existence particle accelerators and storage rings ranging from a few tens of metre to 27 km, the size of its latest project, the Large Hadron Collider (LHC) which is under construction and will be started in 2008. The challenges began with the Intersection Storage Rings (ISR) in the seventies. With a beam pipe length of 2 × 1 km, this accelerator required innovative solutions like bake-out and glow discharge to achieve the required static vacuum level, fight against beam-induced pressure increases and cancel beam neutralisation by trapped electrons. The vacuum system of the Large Electron Positron (LEP) storage ring (in operation between 1989 and 2001) of a total length of 27 km had to cope with very high levels of synchrotron power. The beam vacuum system of LHC (2 × 27 km) integrates some parts at 1.9 K and others at room temperature and will also have to cope with dynamic effects. In addition to the beam vacuum system, LHC requires insulation vacuum for the superconducting magnets and the helium distribution line. Whereas the required pressure is not very low, the leak detection and localisation is significantly more demanding for the insulation vacuum than for the beam vacuum because of the large volumes and the thermal insulation. When the size of an accelerator grows, the difficulties are not only to get a clean and leak tight vacuum system, but also to be able to measure reliably pressure or gas composition over long distances. Furthermore, in the case of LHC the integration of the beam vacuum system was particularly difficult because of the complexity induced by a superconducting magnet scheme and the reduced space available for the beam pipes. Planning and logistics aspects during installation, including the usage of mobile pumping and diagnostic means, were much more difficult to manage in LHC than in previous projects.

  17. Status and Future Developments in Large Accelerator Control Systems

    SciTech Connect

    Karen S. White

    2006-10-31

    Over the years, accelerator control systems have evolved from small hardwired systems to complex computer controlled systems with many types of graphical user interfaces and electronic data processing. Today's control systems often include multiple software layers, hundreds of distributed processors, and hundreds of thousands of lines of code. While it is clear that the next generation of accelerators will require much bigger control systems, they will also need better systems. Advances in technology will be needed to ensure the network bandwidth and CPU power can provide reasonable update rates and support the requisite timing systems. Beyond the scaling problem, next generation systems face additional challenges due to growing cyber security threats and the likelihood that some degree of remote development and operation will be required. With a large number of components, the need for high reliability increases and commercial solutions can play a key role towards this goal. Future control systems will operate more complex machines and need to present a well integrated, interoperable set of tools with a high degree of automation. Consistency of data presentation and exception handling will contribute to efficient operations. From the development perspective, engineers will need to provide integrated data management in the beginning of the project and build adaptive software components around a central data repository. This will make the system maintainable and ensure consistency throughout the inevitable changes during the machine lifetime. Additionally, such a large project will require professional project management and disciplined use of well-defined engineering processes. Distributed project teams will make the use of standards, formal requirements and design and configuration control vital. Success in building the control system of the future may hinge on how well we integrate commercial components and learn from best practices used in other industries.

  18. Semilocal cosmic string networks

    SciTech Connect

    Achucarro, Ana; Salmi, Petja; Urrestilla, Jon

    2007-06-15

    We report on a large-scale numerical study of networks of semilocal cosmic strings in flat space in the parameter regime in which they are perturbatively stable. We find a population of segments with an exponential length distribution and indications of a scaling network without significant loop formation. Very deep in the stability regime strings of superhorizon size grow rapidly and ''percolate'' through the box. We believe these should lead at late times to a population of infinite strings similar to topologically stable strings. However, the strings are very light; scalar gradients dominate the energy density, and the network has thus a global texturelike signature. As a result, the observational constraints, at least from the temperature power spectrum of the cosmic microwave background, on models predicting semilocal strings should be closer to those on global textures or monopoles, rather than on topologically stable gauged cosmic strings.

  19. Cooperative strings and glassy interfaces.

    PubMed

    Salez, Thomas; Salez, Justin; Dalnoki-Veress, Kari; Raphaël, Elie; Forrest, James A

    2015-07-01

    We introduce a minimal theory of glass formation based on the ideas of molecular crowding and resultant string-like cooperative rearrangement, and address the effects of free interfaces. In the bulk case, we obtain a scaling expression for the number of particles taking part in cooperative strings, and we recover the Adam-Gibbs description of glassy dynamics. Then, by including thermal dilatation, the Vogel-Fulcher-Tammann relation is derived. Moreover, the random and string-like characters of the cooperative rearrangement allow us to predict a temperature-dependent expression for the cooperative length ξ of bulk relaxation. Finally, we explore the influence of sample boundaries when the system size becomes comparable to ξ. The theory is in agreement with measurements of the glass-transition temperature of thin polymer films, and allows quantification of the temperature-dependent thickness hm of the interfacial mobile layer. PMID:26100908

  20. Cooperative strings and glassy interfaces.

    PubMed

    Salez, Thomas; Salez, Justin; Dalnoki-Veress, Kari; Raphaël, Elie; Forrest, James A

    2015-07-01

    We introduce a minimal theory of glass formation based on the ideas of molecular crowding and resultant string-like cooperative rearrangement, and address the effects of free interfaces. In the bulk case, we obtain a scaling expression for the number of particles taking part in cooperative strings, and we recover the Adam-Gibbs description of glassy dynamics. Then, by including thermal dilatation, the Vogel-Fulcher-Tammann relation is derived. Moreover, the random and string-like characters of the cooperative rearrangement allow us to predict a temperature-dependent expression for the cooperative length ξ of bulk relaxation. Finally, we explore the influence of sample boundaries when the system size becomes comparable to ξ. The theory is in agreement with measurements of the glass-transition temperature of thin polymer films, and allows quantification of the temperature-dependent thickness hm of the interfacial mobile layer.

  1. Radiation Safety System for SPIDER Neutral Beam Accelerator

    NASA Astrophysics Data System (ADS)

    Sandri, S.; Coniglio, A.; D'Arienzo, M.; Poggi, C.

    2011-12-01

    SPIDER (Source for Production of Ion of Deuterium Extracted from RF Plasma only) and MITICA (Megavolt ITER Injector Concept Advanced) are the ITER neutral beam injector (NBI) testing facilities of the PRIMA (Padova Research Injector Megavolt Accelerated) Center. Both injectors accelerate negative deuterium ions with a maximum energy of 1 MeV for MITICA and 100 keV for SPIDER with a maximum beam current of 40 A for both experiments. The SPIDER facility is classified in Italy as a particle accelerator. At present, the design of the radiation safety system for the facility has been completed and the relevant reports have been presented to the Italian regulatory authorities. Before SPIDER can operate, approval must be obtained from the Italian Regulatory Authority Board (IRAB) following a detailed licensing process. In the present work, the main project information and criteria for the SPIDER injector source are reported together with the analysis of hypothetical accidental situations and safety issues considerations. Neutron and photon nuclear analysis is presented, along with special shielding solutions designed to meet Italian regulatory dose limits. The contribution of activated corrosion products (ACP) to external exposure of workers has also been assessed. Nuclear analysis indicates that the photon contribution to worker external exposure is negligible, and the neutron dose can be considered by far the main radiation protection issue. Our results confirm that the injector has no important radiological impact on the population living around the facility.

  2. Radiation Safety System for SPIDER Neutral Beam Accelerator

    SciTech Connect

    Sandri, S.; Poggi, C.; Coniglio, A.; D'Arienzo, M.

    2011-12-13

    SPIDER (Source for Production of Ion of Deuterium Extracted from RF Plasma only) and MITICA (Megavolt ITER Injector Concept Advanced) are the ITER neutral beam injector (NBI) testing facilities of the PRIMA (Padova Research Injector Megavolt Accelerated) Center. Both injectors accelerate negative deuterium ions with a maximum energy of 1 MeV for MITICA and 100 keV for SPIDER with a maximum beam current of 40 A for both experiments. The SPIDER facility is classified in Italy as a particle accelerator. At present, the design of the radiation safety system for the facility has been completed and the relevant reports have been presented to the Italian regulatory authorities. Before SPIDER can operate, approval must be obtained from the Italian Regulatory Authority Board (IRAB) following a detailed licensing process. In the present work, the main project information and criteria for the SPIDER injector source are reported together with the analysis of hypothetical accidental situations and safety issues considerations. Neutron and photon nuclear analysis is presented, along with special shielding solutions designed to meet Italian regulatory dose limits. The contribution of activated corrosion products (ACP) to external exposure of workers has also been assessed. Nuclear analysis indicates that the photon contribution to worker external exposure is negligible, and the neutron dose can be considered by far the main radiation protection issue. Our results confirm that the injector has no important radiological impact on the population living around the facility.

  3. Preparing accelerator systems for the RHIC sextant commissioning

    SciTech Connect

    Trbojevic, D.; Pilat, F.; Ahrens, L.

    1997-07-01

    The Relativistic Heavy Ion Collider (RHIC) construction is progressing steadily towards completion in 1999 when beams will circulate in both collider rings. One of the major tests of the RHIC project was the commissioning of the first sextant with gold ion beams in early 1997. This is a report on preparation of the RHIC accelerator systems for the first sextant test. It includes beam position monitors, timing, injection correction through the magnetic septum and kickers, current transformers, flags and the ionization beam profile monitors, beam loss monitors, beam and quench permit link system, power supply controls, and the configuration database system. The software and hardware development and coordination of the different systems before commissioning were regularly checked during bi-weekly, and (later) weekly, progress report meetings.

  4. Preparing Accelerator Systems for the RHIC Sextant Commissioning

    NASA Astrophysics Data System (ADS)

    Trbojevic, D.; Pilat, F.; Ahrens, L.; Barton, D.; Clifford, T.; Connoly, R.; Fischer, W.; Harrison, M.; Mackay, W.; Olsen, B.; Peggs, S.; Satogata, T.; Tepikian, S.; Thompson, P.; Trahern, C.; Witkover, R.

    1997-05-01

    The Relativistic Heavy Ion Collider (RHIC) construction is progressing steadily towards the beginning of the 1999 when beams will first be circulated in both collider rings. One of the major tests of the RHIC project is the commissioning of the first sextant with gold ion beams. This is a report on the preparation of the RHIC accelerator systems during the first sextant test, including beam position monitors, timing, injection correction through the magnetic septum and kickers, current transformers, ``flags'' and the ionization beam profile monitors, beam loss monitors, beam and quench permit link system, power supply controls, and the CYBASE data base system. The software and hardware development and coordination of the different systems before commissioning were regularly checked during bi-weekly, and (later) weekly, progress report meetings.

  5. Ion accelerator systems for high power 30 cm thruster operation

    NASA Technical Reports Server (NTRS)

    Aston, G.

    1982-01-01

    Two and three-grid accelerator systems for high power ion thruster operation were investigated. Two-grid translation tests show that over compensation of the 30 cm thruster SHAG grid set spacing the 30 cm thruster radial plasma density variation and by incorporating grid compensation only sufficient to maintain grid hole axial alignment, it is shown that beam current gains as large as 50% can be realized. Three-grid translation tests performed with a simulated 30 cm thruster discharge chamber show that substantial beamlet steering can be reliably affected by decelerator grid translation only, at net-to-total voltage ratios as low as 0.05.

  6. Novel Approach to Linear Accelerator Superconducting Magnet System

    SciTech Connect

    Kashikhin, Vladimir; /Fermilab

    2011-11-28

    Superconducting Linear Accelerators include a superconducting magnet system for particle beam transportation that provides the beam focusing and steering. This system consists of a large number of quadrupole magnets and dipole correctors mounted inside or between cryomodules with SCRF cavities. Each magnet has current leads and powered from its own power supply. The paper proposes a novel approach to magnet powering based on using superconducting persistent current switches. A group of magnets is powered from the same power supply through the common, for the group of cryomodules, electrical bus and pair of current leads. Superconducting switches direct the current to the chosen magnet and close the circuit providing the magnet operation in a persistent current mode. Two persistent current switches were fabricated and tested. In the paper also presented the results of magnetic field simulations, decay time constants analysis, and a way of improving quadrupole magnetic center stability. Such approach substantially reduces the magnet system cost and increases the reliability.

  7. String Mining in Bioinformatics

    NASA Astrophysics Data System (ADS)

    Abouelhoda, Mohamed; Ghanem, Moustafa

    Sequence analysis is a major area in bioinformatics encompassing the methods and techniques for studying the biological sequences, DNA, RNA, and proteins, on the linear structure level. The focus of this area is generally on the identification of intra- and inter-molecular similarities. Identifying intra-molecular similarities boils down to detecting repeated segments within a given sequence, while identifying inter-molecular similarities amounts to spotting common segments among two or multiple sequences. From a data mining point of view, sequence analysis is nothing but string- or pattern mining specific to biological strings. For a long time, this point of view, however, has not been explicitly embraced neither in the data mining nor in the sequence analysis text books, which may be attributed to the co-evolution of the two apparently independent fields. In other words, although the word “data-mining” is almost missing in the sequence analysis literature, its basic concepts have been implicitly applied. Interestingly, recent research in biological sequence analysis introduced efficient solutions to many problems in data mining, such as querying and analyzing time series [49,53], extracting information from web pages [20], fighting spam mails [50], detecting plagiarism [22], and spotting duplications in software systems [14].

  8. String Mining in Bioinformatics

    NASA Astrophysics Data System (ADS)

    Abouelhoda, Mohamed; Ghanem, Moustafa

    Sequence analysis is a major area in bioinformatics encompassing the methods and techniques for studying the biological sequences, DNA, RNA, and proteins, on the linear structure level. The focus of this area is generally on the identification of intra- and inter-molecular similarities. Identifying intra-molecular similarities boils down to detecting repeated segments within a given sequence, while identifying inter-molecular similarities amounts to spotting common segments among two or multiple sequences. From a data mining point of view, sequence analysis is nothing but string- or pattern mining specific to biological strings. For a long time, this point of view, however, has not been explicitly embraced neither in the data mining nor in the sequence analysis text books, which may be attributed to the co-evolution of the two apparently independent fields. In other words, although the word "data-mining" is almost missing in the sequence analysis literature, its basic concepts have been implicitly applied. Interestingly, recent research in biological sequence analysis introduced efficient solutions to many problems in data mining, such as querying and analyzing time series [49,53], extracting information from web pages [20], fighting spam mails [50], detecting plagiarism [22], and spotting duplications in software systems [14].

  9. String loops in the field of braneworld spherically symmetric black holes and naked singularities

    SciTech Connect

    Stuchlík, Z.; Kološ, M. E-mail: martin.kolos@fpf.slu.cz

    2012-10-01

    We study motion of current-carrying string loops in the field of braneworld spherically symmetric black holes and naked singularities. The spacetime is described by the Reissner-Nordström geometry with tidal charge b reflecting the non-local tidal effects coming from the external dimension; both positive and negative values of the spacetime parameter b are considered. We restrict attention to the axisymmetric motion of string loops when the motion can be fully governed by an appropriately defined effective potential related to the energy and angular momentum of the string loops. In dependence on these two constants of the motion, the string loops can be captured, trapped, or can escape to infinity. In close vicinity of stable equilibrium points at the centre of trapped states the motion is regular. We describe how it is transformed to chaotic motion with growing energy of the string loop. In the field of naked singularities the trapped states located off the equatorial plane of the system exist and trajectories unable to cross the equatorial plane occur, contrary to the trajectories in the field of black holes where crossing the equatorial plane is always admitted. We concentrate our attention to the so called transmutation effect when the string loops are accelerated in the deep gravitational field near the black hole or naked singularity by transforming the oscillatory energy to the energy of the transitional motion. We demonstrate that the influence of the tidal charge can be substantial especially in the naked singularity spacetimes with b > 1 where the acceleration to ultrarelativistic velocities with Lorentz factor γ ∼ 100 can be reached, being more than one order higher in comparison with those obtained in the black hole spacetimes.

  10. Tailorable software architectures in the accelerator control system environment

    NASA Astrophysics Data System (ADS)

    Mejuev, Igor; Kumagai, Akira; Kadokura, Eiichi

    2001-08-01

    Tailoring is further evolution of an application after deployment in order to adapt it to requirements that were not accounted for in the original design. End-user tailorability has been extensively researched in applied computer science from HCl and software engineering perspectives. Tailorability allows coping with flexibility requirements, decreasing maintenance and development costs of software products. In general, dynamic or diverse software requirements constitute the need for implementing end-user tailorability in computer systems. In accelerator physics research the factor of dynamic requirements is especially important, due to frequent software and hardware modifications resulting in correspondingly high upgrade and maintenance costs. In this work we introduce the results of feasibility study on implementing end-user tailorability in the software for accelerator control system, considering the design and implementation of distributed monitoring application for 12 GeV KEK Proton Synchrotron as an example. The software prototypes used in this work are based on a generic tailoring platform (VEDICI), which allows decoupling of tailoring interfaces and runtime components. While representing a reusable application-independent framework, VEDICI can be potentially applied for tailoring of arbitrary compositional Web-based applications.

  11. Accelerated Aging System for Prognostics of Power Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Celaya, Jose R.; Vashchenko, Vladislav; Wysocki, Philip; Saha, Sankalita

    2010-01-01

    Prognostics is an engineering discipline that focuses on estimation of the health state of a component and the prediction of its remaining useful life (RUL) before failure. Health state estimation is based on actual conditions and it is fundamental for the prediction of RUL under anticipated future usage. Failure of electronic devices is of great concern as future aircraft will see an increase of electronics to drive and control safety-critical equipment throughout the aircraft. Therefore, development of prognostics solutions for electronics is of key importance. This paper presents an accelerated aging system for gate-controlled power transistors. This system allows for the understanding of the effects of failure mechanisms, and the identification of leading indicators of failure which are essential in the development of physics-based degradation models and RUL prediction. In particular, this system isolates electrical overstress from thermal overstress. Also, this system allows for a precise control of internal temperatures, enabling the exploration of intrinsic failure mechanisms not related to the device packaging. By controlling the temperature within safe operation levels of the device, accelerated aging is induced by electrical overstress only, avoiding the generation of thermal cycles. The temperature is controlled by active thermal-electric units. Several electrical and thermal signals are measured in-situ and recorded for further analysis in the identification of leading indicators of failures. This system, therefore, provides a unique capability in the exploration of different failure mechanisms and the identification of precursors of failure that can be used to provide a health management solution for electronic devices.

  12. Which String Breaks? Revisited

    NASA Astrophysics Data System (ADS)

    Frye, Christopher

    2011-03-01

    Many have seen the common introductory physics demonstration in which a heavy ball hangs from a string, with another identical string hanging freely from the ball. When the instructor pulls the bottom string slowly, the top string breaks. However, when the instructor pulls the bottom string very rapidly, the bottom string breaks. This simple experiment is used to demonstrate inertia and Newton's laws. In The Physics Teacher of November 1996, there is an article in which the authors create a model of this problem in an attempt to explain the outcomes quantitatively. However, their analysis gave strange results. Using an improved model, I will show that the results of this demonstration can be obtained using only simple calculations. This work was funded by a RAMP grant from the University of Central Florida.

  13. N = 2 string amplitudes

    SciTech Connect

    Ooguri, H.

    1995-08-01

    In physics, solvable models have played very important roles. Understanding a simple model in detail teaches us a lot about more complicated models in generic situations. Five years ago, C. Vafa and I found that the closed N = 2 string theory, that is a string theory with the N = 2 local supersymmetry on the worldsheet, is classically equivalent to the self-dual Einstein gravity in four spacetime dimensions. Thus this string theory is solvable at the classical level. More recently, we have examined the N = 2 string partition function for spacial compactifications, and computed it to all order in the string perturbation expansion. The fact that such computation is possible at all suggests that the N = 2 string theory is solvable even quantum mechanically.

  14. Electron string phenomenon: physics and use

    NASA Astrophysics Data System (ADS)

    Donets, Evgeny D.

    2004-01-01

    Electron string phenomenon arises as a result of phase transition of a state of multiply reflected electron beam to this new discovered state of one component electron plasma and can be easily observed in the reflex mode of EBIS operation. The transition goes via a strong instability, which causes considerable electron energy spread, which in its turn suppresses the instability. Electron string state is a stationary state of hot pure electron plasma, which is heated by injected electron beam and cooled because of electron loses. Electron string is quiet in broad regions of experimental parameters, so that it is used for confinement and ionization of positive ions by electron impact to highly charge states similar to electron beams in EBIS. Application of electron strings instead of electron beams for ion production allows to save about 99% of electric power of electron beam and simultaneously to improve reliability of an ion source considerably. The JINR EBIS `Krion-2' in the string mode of operation is used for production of N7+, Ar16+ and Fe24+ ion beams and their acceleration to relativistic energies on the facility of the JINR super conducting one turn injection synchrotron `Nuklotron'. The tubular electron string possibly can exist and it is under study now theoretically and experiments are prepared now. Estimations show that a Tubular Electron String Ion Source (TESIS) could have up to three orders of magnitude higher ion output then a Linear one (LESIS). In frames of nuclear astrophysics electron strings can be used for research of fusion nuclear reactions at low energies in conditions when both beam and target nuclei do not carry orbital electrons. The project NARITA — Nuclear Astrophysics Researches in an Ion Trap Apparatus is proposed. Polarization effects also can be studied.

  15. The Development of a String Sight-Reading Pitch Skill Hierarchy

    ERIC Educational Resources Information Center

    Alexander, Michael L.; Henry, Michele L.

    2012-01-01

    This study was designed to determine a pitch skill hierarchy for string sight-reading, to determine the effects of key on string sight-reading achievement, and to determine the validity of a tonal pattern system as a measurement of melodic sight-reading skill for string players. High school string students (n = 94) obtained a mean score of 27.28…

  16. Modal analysis of a nonuniform string with end mass and variable tension

    NASA Technical Reports Server (NTRS)

    Rheinfurth, M. H.; Galaboff, Z. J.

    1983-01-01

    Modal synthesis techniques for dynamic systems containing strings describe the lateral displacements of these strings by properly chosen shape functions. An iterative algorithm is provided to calculate the natural modes of a nonuniform string and variable tension for some typical boundary conditions including one end mass. Numerical examples are given for a string in a constant and a gravity gradient force field.

  17. Shielding design for a laser-accelerated proton therapy system.

    PubMed

    Fan, J; Luo, W; Fourkal, E; Lin, T; Li, J; Veltchev, I; Ma, C-M

    2007-07-01

    In this paper, we present the shielding analysis to determine the necessary neutron and photon shielding for a laser-accelerated proton therapy system. Laser-accelerated protons coming out of a solid high-density target have broad energy and angular spectra leading to dose distributions that cannot be directly used for therapeutic applications. A special particle selection and collimation device is needed to generate desired proton beams for energy- and intensity-modulated proton therapy. A great number of unwanted protons and even more electrons as a side-product of laser acceleration have to be stopped by collimation devices and shielding walls, posing a challenge in radiation shielding. Parameters of primary particles resulting from the laser-target interaction have been investigated by particle-in-cell simulations, which predicted energy spectra with 300 MeV maximum energy for protons and 270 MeV for electrons at a laser intensity of 2 x 10(21) W cm(-2). Monte Carlo simulations using FLUKA have been performed to design the collimators and shielding walls inside the treatment gantry, which consist of stainless steel, tungsten, polyethylene and lead. A composite primary collimator was designed to effectively reduce high-energy neutron production since their highly penetrating nature makes shielding very difficult. The necessary shielding for the treatment gantry was carefully studied to meet the criteria of head leakage <0.1% of therapeutic absorbed dose. A layer of polyethylene enclosing the whole particle selection and collimation device was used to shield neutrons and an outer layer of lead was used to reduce photon dose from neutron capture and electron bremsstrahlung. It is shown that the two-layer shielding design with 10-12 cm thick polyethylene and 4 cm thick lead can effectively absorb the unwanted particles to meet the shielding requirements. PMID:17664585

  18. A large distributed digital camera system for accelerator beam diagnostics

    NASA Astrophysics Data System (ADS)

    Catani, L.; Cianchi, A.; Di Pirro, G.; Honkavaara, K.

    2005-07-01

    Optical diagnostics, providing images of accelerated particle beams using radiation emitted by particles impinging a radiator, typically a fluorescent screen, has been extensively used, especially on electron linacs, since the 1970's. Higher intensity beams available in the last decade allow extending the use of beam imaging techniques to perform precise measurements of important beam parameters such as emittance, energy, and energy spread using optical transition radiation (OTR). OTR-based diagnostics systems are extensively used on the superconducting TESLA Test Facility (TTF) linac driving the vacuum ultraviolet free electron laser (VUV-FEL) at the Deutsches Elektronen-Synchrotron facility. Up to 30 optical diagnostic stations have been installed at various positions along the 250-m-long linac, each equipped with a high-performance digital camera. This paper describes the new approach to the design of the hardware and software setups required by the complex topology of such a distributed camera system.

  19. Tilted string cosmologies

    NASA Astrophysics Data System (ADS)

    Clancy, Dominic; Feinstein, Alexander; Lidsey, James E.; Tavakol, Reza

    1999-04-01

    Global symmetries of the string effective action are employed to generate tilted, homogeneous Bianchi type VIh string cosmologies from a previously known stiff perfect fluid solution to Einstein gravity. The dilaton field is not constant on the surfaces of homogeneity. The future asymptotic state of the models is interpreted as a plane wave and is itself an exact solution to the string equations of motion to all orders in the inverse string tension. An inhomogeneous generalization of the Bianchi type III model is also found.

  20. Heterotic cosmic strings

    SciTech Connect

    Becker, Katrin; Becker, Melanie; Krause, Axel

    2006-08-15

    We show that all three conditions for the cosmological relevance of heterotic cosmic strings, the right tension, stability and a production mechanism at the end of inflation, can be met in the strongly coupled M-theory regime. Whereas cosmic strings generated from weakly coupled heterotic strings have the well-known problems posed by Witten in 1985, we show that strings arising from M5-branes wrapped around 4-cycles (divisors) of a Calabi-Yau in heterotic M-theory compactifications solve these problems in an elegant fashion.

  1. Statistical mechanics of strings with Y-junctions

    SciTech Connect

    Rivers, R. J.; Steer, D. A.

    2008-07-15

    We investigate the Hagedorn transitions of string networks with Y-junctions as may occur, for example, with (p,q) cosmic superstrings. In a simplified model with three different types of string, the partition function reduces to three generalized coupled XY models. We calculate the phase diagram and show that, as the system is heated, the lightest strings first undergo the Hagedorn transition despite the junctions. There is then a second, higher, critical temperature above which infinite strings of all tensions, and junctions, exist. Conversely, on cooling to low temperatures, only the lightest strings remain, but they collapse into small loops.

  2. An artificial intelligence approach to accelerator control systems

    SciTech Connect

    Schultz, D.E.; Hurd, J.W.; Brown, S.K.

    1987-01-01

    An experiment was recently started at LAMPF to evaluate the power and limitations of using artificial intelligence techniques to solve problems in accelerator control and operation. A knowledge base was developed to describe the characteristics and the relationships of the first 30 devices in the LAMPF H+ beam line. Each device was categorized and pertinent attributes for each category defined. Specific values were assigned in the knowledge base to represent each actual device. Relationships between devices are modeled using the artificial intelligence techniques of rules, active values, and object-oriented methods. This symbolic model, built using the Knowledge Engineering Environment (KEE) system, provides a framework for analyzing faults, tutoring trainee operators, and offering suggestions to assist in beam tuning. Based on information provided by the domain expert responsible for tuning this portion of the beam line, additional rules were written to describe how he tunes, how he analyzes what is actually happening, and how he deals with failures. Initial results have shown that artificial intelligence techniques can be a useful adjunct to traditional methods of numerical simulation. Successful and efficient operation of future accelerators may depend on the proper merging of symbolic reasoning and conventional numerical control algorithms.

  3. Introduction to string field theory

    SciTech Connect

    Lykken, J.; Raby, S.

    1986-01-01

    An action is proposed for an interacting closed bosonic string. Our formalism relies heavily on ideas discussed by Witten for the open bosonic string. The gauge fixed quantum action for the fully interacting open bosonic string is obtained.

  4. Towards a kinetic theory of strings

    SciTech Connect

    Vanchurin, Vitaly

    2011-05-15

    We study the dynamics of strings by means of a distribution function f(A,B,x,t), defined on a 9+1D phase space, where A and B are the correlation vectors of right- and left-moving waves. We derive a transport equation (analogous to a Boltzmann transport equation for particles) that governs the evolution of long strings with Nambu-Goto dynamics, as well as reconnections taken into account. We also derive a system of coupled transport equations (analogous to a Bogoliubov-Born-Green-Kirkwood-Yvon hierarchy for particles) which can simultaneously describe long strings f-tilde(A,B,x,t) as well as simple loops f(convolution sign)(A,B,x,t) made out of four correlation vectors. The formalism can be used to study nonlinear dynamics of fundamental strings, D-brane strings, or field theory strings. For example, the complicated semiscaling behavior of cosmic strings translates into a simple solution of the transport system at small energy densities.

  5. An Accelerated Recursive Doubling Algorithm for Block Tridiagonal Systems

    SciTech Connect

    Seal, Sudip K

    2014-01-01

    Block tridiagonal systems of linear equations arise in a wide variety of scientific and engineering applications. Recursive doubling algorithm is a well-known prefix computation-based numerical algorithm that requires O(M^3(N/P + log P)) work to compute the solution of a block tridiagonal system with N block rows and block size M on P processors. In real-world applications, solutions of tridiagonal systems are most often sought with multiple, often hundreds and thousands, of different right hand sides but with the same tridiagonal matrix. Here, we show that a recursive doubling algorithm is sub-optimal when computing solutions of block tridiagonal systems with multiple right hand sides and present a novel algorithm, called the accelerated recursive doubling algorithm, that delivers O(R) improvement when solving block tridiagonal systems with R distinct right hand sides. Since R is typically about 100 1000, this improvement translates to very significant speedups in practice. Detailed complexity analyses of the new algorithm with empirical confirmation of runtime improvements are presented. To the best of our knowledge, this algorithm has not been reported before in the literature.

  6. Covariant Closed String Coherent States

    SciTech Connect

    Hindmarsh, Mark; Skliros, Dimitri

    2011-02-25

    We give the first construction of covariant coherent closed string states, which may be identified with fundamental cosmic strings. We outline the requirements for a string state to describe a cosmic string, and provide an explicit and simple map that relates three different descriptions: classical strings, light cone gauge quantum states, and covariant vertex operators. The resulting coherent state vertex operators have a classical interpretation and are in one-to-one correspondence with arbitrary classical closed string loops.

  7. Covariant closed string coherent states.

    PubMed

    Hindmarsh, Mark; Skliros, Dimitri

    2011-02-25

    We give the first construction of covariant coherent closed string states, which may be identified with fundamental cosmic strings. We outline the requirements for a string state to describe a cosmic string, and provide an explicit and simple map that relates three different descriptions: classical strings, light cone gauge quantum states, and covariant vertex operators. The resulting coherent state vertex operators have a classical interpretation and are in one-to-one correspondence with arbitrary classical closed string loops. PMID:21405564

  8. Radiological Hazard of Spallation Products in Accelerator-Driven System

    SciTech Connect

    Saito, M.; Stankovskii, A.; Artisyuk, V.; Korovin, Yu.; Shmelev, A.; Titarenko, Yu.

    2002-09-15

    The central issue underlying this paper is related to elucidating the hazard of radioactive spallation products that might be an important factor affecting the design option of accelerator-driven systems (ADSs). Hazard analysis based on the concept of Annual Limit on Intake identifies alpha-emitting isotopes of rare earths (REs) (dysprosium, gadolinium, and samarium) as the dominant contributors to the overall toxicity of traditional (W, Pb, Pb-Bi) targets. The matter is addressed from several points of view: code validation to simulate their yields, choice of material for the neutron producing targets, and challenging the beam type. The paper quantitatively determines the domain in which the toxicity of REs exceeds that of polonium activation products broadly discussed now in connection with advertising lead-bismuth technology for the needs of ADSs.

  9. A high power accelerator driver system for spallation neutron sources

    SciTech Connect

    Jason, A.; Blind, B.; Channell, P.

    1996-07-01

    This is the final report of a two-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). For several years, the Los Alamos Meson Physics Facility (LAMPF) and the Proton Storage Ring (PSR) have provided a successful driver for the nearly 100-kW Los Alamos Neutron Scattering Center (LANSCE) source. The authors have studied an upgrade to this system. The goal of this effort was to establish a credible design for the accelerator driver of a next-generation source providing 1-MW of beam power. They have explored a limited subset of the possible approaches to a driver and have considered only the low 1-MW beam power. The next-generation source must utilize the optimum technology and may require larger neutron intensities than they now envision.

  10. Accelerated vascular disease in systemic lupus erythematosus: role of macrophage.

    PubMed

    Al Gadban, Mohammed M; Alwan, Mohamed M; Smith, Kent J; Hammad, Samar M

    2015-04-01

    Atherosclerosis is a chronic inflammatory condition that is considered a major cause of death worldwide. Striking phenomena of atherosclerosis associated with systemic lupus erythematosus (SLE) is its high incidence in young patients. Macrophages are heterogeneous cells that differentiate from hematopoietic progenitors and reside in different tissues to preserve tissue integrity. Macrophages scavenge modified lipids and play a major role in the development of atherosclerosis. When activated, macrophages secret inflammatory cytokines. This activation triggers apoptosis of cells in the vicinity of macrophages. As such, macrophages play a significant role in tissue remodeling including atherosclerotic plaque formation and rupture. In spite of studies carried on identifying the role of macrophages in atherosclerosis, this role has not been studied thoroughly in SLE-associated atherosclerosis. In this review, we address factors released by macrophages as well as extrinsic factors that may control macrophage behavior and their effect on accelerated development of atherosclerosis in SLE. PMID:25638414

  11. A GPGPU accelerated modeling environment for quantitatively characterizing karst systems

    NASA Astrophysics Data System (ADS)

    Myre, J. M.; Covington, M. D.; Luhmann, A. J.; Saar, M. O.

    2011-12-01

    The ability to derive quantitative information on the geometry of karst aquifer systems is highly desirable. Knowing the geometric makeup of a karst aquifer system enables quantitative characterization of the systems response to hydraulic events. However, the relationship between flow path geometry and karst aquifer response is not well understood. One method to improve this understanding is the use of high speed modeling environments. High speed modeling environments offer great potential in this regard as they allow researchers to improve their understanding of the modeled karst aquifer through fast quantitative characterization. To that end, we have implemented a finite difference model using General Purpose Graphics Processing Units (GPGPUs). GPGPUs are special purpose accelerators which are capable of high speed and highly parallel computation. The GPGPU architecture is a grid like structure, making it is a natural fit for structured systems like finite difference models. To characterize the highly complex nature of karst aquifer systems our modeling environment is designed to use an inverse method to conduct the parameter tuning. Using an inverse method reduces the total amount of parameter space needed to produce a set of parameters describing a system of good fit. Systems of good fit are determined with a comparison to reference storm responses. To obtain reference storm responses we have collected data from a series of data-loggers measuring water depth, temperature, and conductivity at locations along a cave stream with a known geometry in southeastern Minnesota. By comparing the modeled response to those of the reference responses the model parameters can be tuned to quantitatively characterize geometry, and thus, the response of the karst system.

  12. Wave diffraction by a cosmic string

    NASA Astrophysics Data System (ADS)

    Fernández-Núñez, Isabel; Bulashenko, Oleg

    2016-08-01

    We show that if a cosmic string exists, it may be identified through characteristic diffraction pattern in the energy spectrum of the observed signal. In particular, if the string is on the line of sight, the wave field is shown to fit the Cornu spiral. We suggest a simple procedure, based on Keller's geometrical theory of diffraction, which allows to explain wave effects in conical spacetime of a cosmic string in terms of interference of four characteristic rays. Our results are supposed to be valid for scalar massless waves, including gravitational waves, electromagnetic waves, or even sound in case of condensed matter systems with analogous topological defects.

  13. RFQ (radio-frequency quadrupole) accelerator tuning system

    DOEpatents

    Bolie, V.W.

    1988-04-12

    A cooling system is provided for maintaining a preselected operating temperature in a device, which may be an RFQ accelerator, having a variable heat removal requirement, by circulating a cooling fluid through a cooling system remote from the device. Internal sensors in the device enable an estimated error signal to be generated from parameters which are indicative of the heat removal requirement from the device. Sensors are provided at predetermined locations in the cooling system for outputting operational temperature signals. Analog and digital computers define a control signal functionally related to the temperature signals and the estimated error signal, where the control signal is defined effective to return the device to the preselected operating temperature in a stable manner. The cooling system includes a first heat sink responsive to a first portion of the control signal to remove heat from a major portion of the circulating fluid. A second heat sink is responsive to a second portion of the control to remove heat from a minor portion of the circulating fluid. The cooled major and minor portions of the circulating fluid are mixed in responsive to a mixing portion of the control signal, which is effective to proportion the major and minor portions of the circulating fluid to establish a mixed fluid temperature which is effective to define the preselected operating temperature for the remote device. 3 figs., 2 tabs.

  14. Medical record linkage in health information systems by approximate string matching and clustering

    PubMed Central

    Sauleau, Erik A; Paumier, Jean-Philippe; Buemi, Antoine

    2005-01-01

    Background Multiplication of data sources within heterogeneous healthcare information systems always results in redundant information, split among multiple databases. Our objective is to detect exact and approximate duplicates within identity records, in order to attain a better quality of information and to permit cross-linkage among stand-alone and clustered databases. Furthermore, we need to assist human decision making, by computing a value reflecting identity proximity. Methods The proposed method is in three steps. The first step is to standardise and to index elementary identity fields, using blocking variables, in order to speed up information analysis. The second is to match similar pair records, relying on a global similarity value taken from the Porter-Jaro-Winkler algorithm. And the third is to create clusters of coherent related records, using graph drawing, agglomerative clustering methods and partitioning methods. Results The batch analysis of 300,000 "supposedly" distinct identities isolates 240,000 true unique records, 24,000 duplicates (clusters composed of 2 records) and 3,000 clusters whose size is greater than or equal to 3 records. Conclusion Duplicate-free databases, used in conjunction with relevant indexes and similarity values, allow immediate (i.e.: real-time) proximity detection when inserting a new identity. PMID:16219102

  15. k-strings as fundamental strings

    NASA Astrophysics Data System (ADS)

    Giataganas, Dimitrios

    2015-05-01

    It has been noticed that the k-string observables can be expressed in terms of the fundamental string ones. We identify a sufficient condition for a generic gravity dual background which when satisfied the mapping can be done. The condition is naturally related to a preserved quantity under the T-dualities acting on the Dp-brane describing the high representation Wilson loops. We also find the explicit relation between the observables of the heavy k-quark and the single quark states. As an application to our generic study and motivated by the fact that the anisotropic theories satisfy our condition, we compute the width of the k-string in these theories to find that the logarithmic broadening is still present, but the total result is affected by the anisotropy of the space.

  16. Progress in string theory

    NASA Astrophysics Data System (ADS)

    Maldacena, Juan Martín

    D-Branes on Calabi-Yau manifolds / Paul S. Aspinwall -- Lectures on AdS/CFT / Juan M. Maldacena -- Tachyon dynamics in open string theory / Ashoke Sen -- TASI/PITP/ISS lectures on moduli and microphysics / Eva Silverstein -- The duality cascade / Matthew J. Strassler -- Perturbative computations in string field theory / Washington Taylor -- Student seminars -- Student participants -- Lecturers, directors, and local organizing committee.

  17. Stable Charged Cosmic Strings

    SciTech Connect

    Weigel, H.; Quandt, M.; Graham, N.

    2011-03-11

    We study the quantum stabilization of a cosmic string by a heavy fermion doublet in a reduced version of the standard model. We show that charged strings, obtained by populating fermionic bound state levels, become stable if the electroweak bosons are coupled to a fermion that is less than twice as heavy as the top quark. This result suggests that extraordinarily large fermion masses or unrealistic couplings are not required to bind a cosmic string in the standard model. Numerically we find the most favorable string profile to be a simple trough in the Higgs vacuum expectation value of radius {approx_equal}10{sup -18} m. The vacuum remains stable in our model, because neutral strings are not energetically favored.

  18. Stable charged cosmic strings.

    PubMed

    Weigel, H; Quandt, M; Graham, N

    2011-03-11

    We study the quantum stabilization of a cosmic string by a heavy fermion doublet in a reduced version of the standard model. We show that charged strings, obtained by populating fermionic bound state levels, become stable if the electroweak bosons are coupled to a fermion that is less than twice as heavy as the top quark. This result suggests that extraordinarily large fermion masses or unrealistic couplings are not required to bind a cosmic string in the standard model. Numerically we find the most favorable string profile to be a simple trough in the Higgs vacuum expectation value of radius ≈10(-18)  m. The vacuum remains stable in our model, because neutral strings are not energetically favored. PMID:21469786

  19. The DPC-2000 advanced control system for the Dynamitron accelerator

    NASA Astrophysics Data System (ADS)

    Kestler, Bernard A.; Lisanti, Thomas F.

    1993-07-01

    The DPC-2000 is an advanced control system utilizing the latest technology in computer control circuitry and components. Its overall design is modular and technologically advanced to keep up with customer and engineering demands. The full control system is presented as four units. They are the Remote I/O (Input / Output), Local Analog and Digital I/O, Operator Interface and the Main Computer. The central processing unit, the heart of the system, executes a high level language program that communicates to the different sub-assemblies through advanced serial and parallel communication lines. All operational parameters of the accelerator are monitored, controlled and corrected at close to 20 times per second. The operator is provided with a selection of many informative screen displays. The control program handles all graphic screen displays and the updating of these screens directly; it does not have to communicate to a display terminal. This adds to the quick response and excellent operator feedback received while operating the machine. The CPU also has the ability to store and record all process variable setpoints for each product that will be treated. This allows the operator to set up the process parameters by selecting the product identification code from a menu presented on the display screen. All process parameters are printed to report at regular intervals during a process run for later analysis and record keeping.

  20. MYRRHA: A multipurpose accelerator driven system for research & development

    NASA Astrophysics Data System (ADS)

    Abderrahim, H. Aı̈t; Kupschus, P.; Malambu, E.; Benoit, Ph; Van Tichelen, K.; Arien, B.; Vermeersch, F.; D'hondt, P.; Jongen, Y.; Ternier, S.; Vandeplassche, D.

    2001-05-01

    SCK·CEN, the Belgian Nuclear Research Centre, in partnership with IBA s.a., Ion Beam Applications, is designing an ADS prototype, MYRRHA, and is conducting an associated R&D programme. The project focuses primarily on research on structural materials, nuclear fuel, liquid metals and associated aspects, on subcritical reactor physics and subsequently on applications such as nuclear waste transmutation, radioisotope production and safety research on sub-critical systems. The MYRRHA system is intended to be a multipurpose R&D facility and is expected to become a new major research infrastructure for the European partners presently involved in the ADS Demo development. Ion Beam Applications is performing the accelerator development. Currently the preliminary conceptual design of the MYRRHA system is under way and an intensive R&D programme is assessing the points of greatest risk in the present design. This work will define the final choice of characteristics of the facility. In this paper, we will report on the status of the pre-design study as of June 2000 as well as on the methods and results of the R&D programme.

  1. Accelerated Molecular Dynamics Simulations of Reactive Hydrocarbon Systems

    SciTech Connect

    Stuart, Steven J.

    2014-02-25

    The research activities in this project consisted of four different sub-projects. Three different accelerated dynamics techniques (parallel replica dynamics, hyperdynamics, and temperature-accelerated dynamics) were applied to the modeling of pyrolysis of hydrocarbons. In addition, parallel replica dynamics was applied to modeling of polymerization.

  2. Development of an automatic frequency measurement system for RF linear accelerator magnetrons

    NASA Astrophysics Data System (ADS)

    Cha, Sungsu; Kim, Yujong; Lee, Byeong-No; Joo, Youngwoo; Lee, Soo Min; Lee, Byung Cheol; Cha, Hyungki; Lee, Seung Hyun; Park, Hyung Dal; Song, Ki Beak

    2015-06-01

    An X-band [9300 MHz] magnetron frequency measurement system was developed for the electron linear accelerators at the Korean Atomic Energy Research Institute (KAERI). The measurement and the display of the RF frequency during the accelerator operation time is a crucial factor for continuous operation for two key reasons. Firstly, if the RF frequency of the magnetron is not known, then the amount of frequency tuning cannot be known, and the appropriate RF power cannot be supplied to the accelerating-structure. Second, values including the accelerating-structure's coolingwater temperature setting, the solenoid-magnet's cooling-water temperature setting, and the tuning of the source's (magnetron's) frequency can be undertaken because the RF frequency is used as the reference. A key component of the accelerator is the accelerating-structure. The volume of the accelerating-structure changes according to the environment's temperature; there, the resonance frequency of the accelerating-structure varies. When the resonance frequency of the accelerator is changed, the output becomes unstable, and a low beam energy is obtained. Accordingly, was developed a magnetron frequency-measuring device in order to stabilize the accelerator's operation. The results of the test demonstrate that the measurement's accurate up to 100 kHz, which enables the provision of an accurate RF power to the accelerating -structure. In this paper, we discuss the RF frequency measurement system for the magnetron to enable a more stable accelerator operation in a linac.

  3. High-performance control system for a heavy-ion medical accelerator

    SciTech Connect

    Lancaster, H.D.; Magyary, S.B.; Sah, R.C.

    1983-03-01

    A high performance control system is being designed as part of a heavy ion medical accelerator. The accelerator will be a synchrotron dedicated to clinical and other biomedical uses of heavy ions, and it will deliver fully stripped ions at energies up to 800 MeV/nucleon. A key element in the design of an accelerator which will operate in a hospital environment is to provide a high performance control system. This control system will provide accelerator modeling to facilitate changes in operating mode, provide automatic beam tuning to simplify accelerator operations, and provide diagnostics to enhance reliability. The control system being designed utilizes many microcomputers operating in parallel to collect and transmit data; complex numerical computations are performed by a powerful minicomputer. In order to provide the maximum operational flexibility, the Medical Accelerator control system will be capable of dealing with pulse-to-pulse changes in beam energy and ion species.

  4. Universality and string theory

    NASA Astrophysics Data System (ADS)

    Bachlechner, Thomas Christian

    The first run at the Large Hadron Collider has deeply challenged conventional notions of naturalness, and CMB polarization experiments are about to open a new window to early universe cosmology. As a compelling candidate for the ultraviolet completion of the standard model, string theory provides a prime opportunity to study both early universe cosmology and particle physics. However, relating low energy observations to ultraviolet physics requires knowledge of the metastable states of string theory through the study of vacua. While it is difficult to directly obtain infrared data from explicit string theory constructions, string theory imposes constraints on low energy physics. The study of ensembles of low energy theories consistent with ultra-violet constraints provides insight on generic features we might expect to occur in string compactifications. In this thesis we present a statistical treatment of vacuum stability and vacuum properties in the context of random supergravity theories motivated by string theory. Early universe cosmology provides another avenue to high energy physics. From the low energy perspective large field inflation is typically considered highly unnatural: the scale relevant for the diameter of flat regions in moduli space is sub-Planckian in regions of perturbative control. To approach this problem, we consider generic Calabi-Yau compactifications of string theory and find that super-Planckian diameters of axion fundamental domains in fact arise generically. We further demonstrate that such super-Planckian flat regions are plausibly consistent with theWeak Gravity Conjecture.

  5. Supersymmetry and String Theory

    NASA Astrophysics Data System (ADS)

    Dine, Michael

    2016-01-01

    Preface to the first edition; Preface to the second edition; A note on choice of metric; Text website; Part I. Effective Field Theory: The Standard Model, Supersymmetry, Unification: 1. Before the Standard Model; 2. The Standard Model; 3. Phenomenology of the Standard Model; 4. The Standard Model as an effective field theory; 5. Anomalies, instantons and the strong CP problem; 6. Grand unification; 7. Magnetic monopoles and solitons; 8. Technicolor: a first attempt to explain hierarchies; Part II. Supersymmetry: 9. Supersymmetry; 10. A first look at supersymmetry breaking; 11. The Minimal Supersymmetric Standard Model; 12. Supersymmetric grand unification; 13. Supersymmetric dynamics; 14. Dynamical supersymmetry breaking; 15. Theories with more than four conserved supercharges; 16. More supersymmetric dynamics; 17. An introduction to general relativity; 18. Cosmology; 19. Astroparticle physics and inflation; Part III. String Theory: 20. Introduction; 21. The bosonic string; 22. The superstring; 23. The heterotic string; 24. Effective actions in ten dimensions; 25. Compactification of string theory I. Tori and orbifolds; 26. Compactification of string theory II. Calabi–Yau compactifications; 27. Dynamics of string theory at weak coupling; 28. Beyond weak coupling: non-perturbative string theory; 29. Large and warped extra dimensions; 30. The landscape: a challenge to the naturalness principle; 31. Coda: where are we headed?; Part IV. The Appendices: Appendix A. Two-component spinors; Appendix B. Goldstone's theorem and the pi mesons; Appendix C. Some practice with the path integral in field theory; Appendix D. The beta function in supersymmetric Yang–Mills theory; References; Index.

  6. A Framework for a General Purpose Intelligent Control System for Particle Accelerators. Phase II Final Report

    SciTech Connect

    Dr. Robert Westervelt; Dr. William Klein; Dr. Michael Kroupa; Eric Olsson; Rick Rothrock

    1999-06-28

    Vista Control Systems, Inc. has developed a portable system for intelligent accelerator control. The design is general in scope and is thus configurable to a wide range of accelerator facilities and control problems. The control system employs a multi-layer organization in which knowledge-based decision making is used to dynamically configure lower level optimization and control algorithms.

  7. Cosmological cosmic strings

    NASA Technical Reports Server (NTRS)

    Gregory, Ruth

    1988-01-01

    The effect of an infinite cosmic string on a cosmological background is investigated. It is found that the metric is approximately a scaled version of the empty space string metric, i.e., conical in nature. Results are used to place bounds on the amount of cylindrical gravitational radiation currently emitted by such a string. The gravitational radiation equations are then analyzed explicitly and it is shown that even initially large disturbances are rapidly damped as the expansion proceeds. The implications of the gravitational radiation background and the limitations of the quadrupole formula are discussed.

  8. Final Report: "Strings 2014"

    SciTech Connect

    Witten, Edward

    2015-10-21

    The Strings 2014 meeting was held at Princeton University June 23-27, 2014, co-sponsored by Princeton University and the Institute for Advanced Study. The goal of the meeting was to provide a stimulating and up-to-date overview of research in string theory and its relations to other areas of physics and mathematics, ranging from geometry to quantum field theory, condensed matter physics, and more. This brief report lists committee members and speakers but contains no scientific information. Note that the talks at Strings 2014 were videotaped and are available on the conference website: http://physics.princeton.edustrings2014/Talk_titles.shtml.

  9. Supermassive cosmic string compactifications

    SciTech Connect

    Blanco-Pillado, Jose J.; Reina, Borja; Sousa, Kepa; Urrestilla, Jon E-mail: borja.reina@ehu.es E-mail: jon.urrestilla@ehu.es

    2014-06-01

    The space-time dimensions transverse to a static straight cosmic string with a sufficiently large tension (supermassive cosmic strings) are compact and typically have a singularity at a finite distance form the core. In this paper, we discuss how the presence of multiple supermassive cosmic strings in the 4d Abelian-Higgs model can induce the spontaneous compactification of the transverse space and explicitly construct solutions where the gravitational background becomes regular everywhere. We discuss the embedding of this model in N = 1 supergravity and show that some of these solutions are half-BPS, in the sense that they leave unbroken half of the supersymmetries of the model.

  10. Ion extraction capabilities of two-grid accelerator systems. [for spacecraft propulsion

    NASA Technical Reports Server (NTRS)

    Rovang, D. C.; Wilbur, P. J.

    1984-01-01

    An experimental investigation into the ion extraction capabilities of two-grid accelerator systems common to electrostatic ion thrusters is described. A large body of experimental data which facilitates the selection of the accelerator system geometries and operating parameters necessary to maximize the extracted ion current is presented. Results suggest that the impingement-limited perveance is not dramatically affected by reductions in screen hole diameter to 0.5 mm. Impingement-limited performance is shown to depend most strongly on grid separation distance, accelerator hole diameter ratio, the discharge-to-total accelerating voltage ratio, and the net-to-total accelerating voltage ratio. Results obtained at small grid separation ratios suggest a new grid operating condition where high beam current per hole levels are achieved at a specified net accelerating voltage. It is shown that this operating condition is realized at an optimum ratio of net-to-total accelerating voltage ratio which is typically quite high.

  11. Systems and methods for cylindrical hall thrusters with independently controllable ionization and acceleration stages

    DOEpatents

    Diamant, Kevin David; Raitses, Yevgeny; Fisch, Nathaniel Joseph

    2014-05-13

    Systems and methods may be provided for cylindrical Hall thrusters with independently controllable ionization and acceleration stages. The systems and methods may include a cylindrical channel having a center axial direction, a gas inlet for directing ionizable gas to an ionization section of the cylindrical channel, an ionization device that ionizes at least a portion of the ionizable gas within the ionization section to generate ionized gas, and an acceleration device distinct from the ionization device. The acceleration device may provide an axial electric field for an acceleration section of the cylindrical channel to accelerate the ionized gas through the acceleration section, where the axial electric field has an axial direction in relation to the center axial direction. The ionization section and the acceleration section of the cylindrical channel may be substantially non-overlapping.

  12. Disposition of Nuclear Waste Using Subcritical Accelerator-Driven Systems

    SciTech Connect

    Doolen, G.D.; Venneri, F.; Li, N.; Williamson, M.A.; Houts, M.; Lawrence, G.

    1998-06-27

    ATW destroys virtually all the plutonium and higher actinides without reprocessing the spent fuel in a way that could lead to weapons material diversion. An ATW facility consists of three major elements: (1) a high-power proton linear accelerator; (2) a pyrochemical spent fuel treatment i waste cleanup system; (3) a liquid lead-bismuth cooled burner that produces and utilizes an intense source-driven neutron flux for transmutation in a heterogeneous (solid fuel) core. The concept is the result of many years of development at LANL as well as other major international research centers. Once demonstrated and developed, ATW could be an essential part of a global non-proliferation strategy for countries that could build up large quantities of plutonium from their commercial reactor waste. ATW technology, initially proposed in the US, has received wide and rapidly increasing attention abroad, especially in Europe and the Far East with major programs now being planned, organized and tided. Substantial convergence presently exists on the technology choices among the programs, opening the possibility of a strong and effective international collaboration on the phased development of the ATW technology.

  13. Novel learning accelerates systems consolidation of a contextual fear memory.

    PubMed

    Haubrich, Josue; Cassini, Lindsey Freitas; Diehl, Felipe; Santana, Fabiana; Fürstenau de Oliveira, Lucas; de Oliveira Alvares, Lucas; Quillfeldt, Jorge Alberto

    2016-07-01

    After initial encoding memories may undergo a time-dependent reorganization, becoming progressively independent from the hippocampus (HPC) and dependent on cortical regions such as the anterior cingulate cortex (ACC). Although the mechanisms underlying systems consolidation are somewhat known, the factors determining its temporal dynamics are still poorly understood. Here, we studied the influence of novel learning occurring between training and test sessions on the time-course of HPC- and ACC-dependency of contextual fear conditioning (CFC) memory expression. We found that muscimol was disruptive when infused into the HPC up to 35 days after training, while the ACC is vulnerable only after 45 days. However, when animals were subjected to a series of additional, distinct tasks to be learned within the first 3 weeks, muscimol became effective sooner. Muscimol had no effect in the HPC at 20 days after training, exactly when the ACC becomes responsive to this treatment. Thus, our data indicates that the encoding of new information generates a tight interplay between distinct memories, accelerating the reorganization of previously stored long term memories between the hippocampal and cortical areas. © 2016 Wiley Periodicals, Inc.

  14. Analysis of blood flow through a model of the human arterial system under periodic body acceleration.

    PubMed

    Sud, V K; Sekhon, G S

    1986-01-01

    The human system may be subjected to a body acceleration deliberated for example by making subjects lie down on vibrating tables or more frequently unintentionally, for example during travel in water and land or in air and space. The present study is concerned with the effects of externally imposed body accelerations on blood flow in a branched system of arteries. A finite-element model of flow in the arterial system subject to periodic body accelerations is presented. Computational results on the flow rates through selected arteries and the corresponding inlet and outlet pressures under different conditions (magnitude, frequency and direction) of applied acceleration are presented.

  15. 511 keV photons from superconducting cosmic strings.

    PubMed

    Ferrer, Francesc; Vachaspati, Tanmay

    2005-12-31

    We show that a tangle of light superconducting strings in the Milky Way could be the source of the observed 511 keV emission from electron-positron annihilation in the Galactic bulge. The scenario predicts a flux that is in agreement with observations if the strings are at the approximately 1 TeV scale, making the particle physics within reach of planned accelerator experiments. The emission is directly proportional to the galactic magnetic field, and future observations should be able to differentiate the superconducting string scenario from other proposals. PMID:16486335

  16. Vacuum Systems Consensus Guideline for Department of Energy Accelerator Laboratories

    SciTech Connect

    Casey,R.; Haas, E.; Hseuh, H-C.; Kane, S.; Lessard, E.; Sharma, S.; Collins, J.; Toter, W. F.; Olis, D. R.; Pushka, D. R.; Ladd, P.; Jobe, R. K.

    2008-09-09

    inspections of materials, in-process fabrications, non-destructive tests, and acceptance test. (3) Documentation, traceability, and accountability must be maintained for each unique pressure vessel or system, including descriptions of design, pressure conditions, testing, inspection, operation, repair, and maintenance. The purpose of this guideline is to establish a set of expectations and recommendations which will satisfy the requirements for vacuum vessels in general and particularly when an equivalent level of safety as required by 10 CFR 851 must be provided. It should be noted that these guidelines are not binding on DOE Accelerator Laboratories and that other approaches may be equally acceptable in addressing the Part 851 requirements.

  17. Strings at finite temperature

    SciTech Connect

    Arago C. de; Bazeia, D.; Eboli, O.J.P.; Marques, G.C.

    1985-12-15

    We obtain a semiclassical evaluation of the temperature for which the free energy of the strings of spontaneously broken scalar electrodynamics vanishes. We argue that, above this temperature, these objects should play a significant physical role.

  18. Universality in string interactions

    NASA Astrophysics Data System (ADS)

    Huang, Yu-tin; Schlotterer, Oliver; Wen, Congkao

    2016-09-01

    In this note, we provide evidence for universality in the low-energy expansion of tree-level string interactions. More precisely, in the α'-expansion of tree-level scattering amplitudes, we conjecture that the leading transcendental coefficient at each order in α' is universal for all perturbative string theories. We have checked this universality up to seven points and trace its origin to the ability to restructure the disk integrals of open bosonic string into those of the superstring. The accompanying kinematic functions have the same low-energy limit and do not introduce any transcendental numbers in their α'-corrections. Universality in the closed-string sector then follows from KLT-relations.

  19. Subsurface drill string

    DOEpatents

    Casper, William L.; Clark, Don T.; Grover, Blair K.; Mathewson, Rodney O.; Seymour, Craig A.

    2008-10-07

    A drill string comprises a first drill string member having a male end; and a second drill string member having a female end configured to be joined to the male end of the first drill string member, the male end having a threaded portion including generally square threads, the male end having a non-threaded extension portion coaxial with the threaded portion, and the male end further having a bearing surface, the female end having a female threaded portion having corresponding female threads, the female end having a non-threaded extension portion coaxial with the female threaded portion, and the female end having a bearing surface. Installation methods, including methods of installing instrumented probes are also provided.

  20. Instantons in string theory

    SciTech Connect

    Ahlén, Olof

    2015-12-17

    These proceedings from the second Caesar Lattes meeting in Rio de Janeiro 2015 are a brief introduction to how automorphic forms appear in the low energy effective action of maximally supersymmetric string theory. The explicit example of the R{sup 4}-interaction of type IIB string theory in ten dimensions is discussed. Its Fourier expansion is interpreted in terms of perturbative and non-perturbative contributions to the four graviton amplitude.

  1. Instabilities of twisted strings

    NASA Astrophysics Data System (ADS)

    Forgács, Péter; Lukács, Árpád

    2009-12-01

    A linear stability analysis of twisted flux-tubes (strings) in an SU(2) semilocal theory — an Abelian-Higgs model with two charged scalar fields with a global SU(2) symmetry — is carried out. Here the twist refers to a relative phase between the two complex scalars (with linear dependence on, say, the z coordinate), and importantly it leads to a global current flowing along the the string. Such twisted strings bifurcate with the Abrikosov-Nielsen-Olesen (ANO) solution embedded in the semilocal theory. Our numerical investigations of the small fluctuation spectrum confirm previous results that twisted strings exhibit instabilities whose amplitudes grow exponentially in time. More precisely twisted strings with a single magnetic flux quantum admit a continuous family of unstable eigenmodes with harmonic z dependence, indexed by a wavenumber kin[-km, km]. Carrying out a perturbative semi-analytic analysis of the bifurcation, it is found that the purely numerical results are very well reproduced. This way one obtains not only a good qualitative description of the twisted solutions themselves as well as of their instabilities, but also a quantitative description of the numerical results. Our semi-analytic results indicate that in close analogy to the known instability of the embedded ANO vortex a twisted string is also likely to expand in size caused by the spreading out of its magnetic flux.

  2. Qualification of a computer program for drill string dynamics

    SciTech Connect

    Stone, C.M.; Carne, T.G.; Caskey, B.C.

    1985-01-01

    A four point plan for the qualification of the GEODYN drill string dynamics computer program is described. The qualification plan investigates both modal response and transient response of a short drill string subjected to simulated cutting loads applied through a polycrystalline diamond compact (PDC) bit. The experimentally based qualification shows that the analytical techniques included in Phase 1 GEODYN correctly simulate the dynamic response of the bit-drill string system. 6 refs., 8 figs.

  3. Cosmic D- and DF-strings from D3D3: Black strings and BPS limit

    SciTech Connect

    Kim, Taekyung; Kim, Yoonbai; Kyae, Bumseok; Lee, Jungjai

    2008-03-15

    We study D- and DF-strings in a D3D3 system by using Dirac-Born-Infeld type action. In the presence of an electric flux from the transverse direction, we discuss gravitating thick D-string solutions of a spatial manifold, S{sup 2}xR{sup 1}, in which straight D-strings stretched along the R{sup 1} direction are attached to the south and north poles of the two-sphere. There is a horizon along its equator, which means the structure of black strings is formed. We also discuss the BPS limit for thin parallel D- and DF-strings in both flat and curved spacetime. We obtain the BPS sum rule for an arbitrarily-separated multistring configuration with a Gaussian type tachyon potential. At the site of each thin BPS D(F)-string, the pressure takes a finite value. We find that there exists a maximum deficit angle {pi} in the conical geometry induced by thin BPS D- and DF-strings.

  4. Acceleration units for the Induction Linac Systems Experiment (ILSE)

    SciTech Connect

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

    1989-03-01

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

  5. A semi-automated system for the characterization of NLC accelerating structures

    SciTech Connect

    Hanna, S.M.; Bowden, G.B.; Hoag, H.A.; Loewen, R.; Vlieks, A.E.; Wang, J.W.

    1995-06-01

    *A system for characterizing the phase shift per cell of a long X-band accelerator structure is described. The fields within the structure are perturbed by a small cylindrical metal bead pulled along the axis. A computer controls the bead position and processes the data from a network analyzer connected to the accelerator section. Measurements made on prototype accelerator sections are described, and they are shown to be in good agreement with theory.

  6. Energetics and conserved quantity of an axially moving string undergoing three-dimensional nonlinear vibration

    NASA Astrophysics Data System (ADS)

    Chen, Liqun; Lim, C. W.; Ding, Hu

    2008-04-01

    Nonlinear three-dimensional vibration of axially moving strings is investigated in the view of energetics. The governing equation is derived from the Eulerian equation of motion of a continuum for axially accelerating strings. The time-rate of the total mechanical energy associated with the vibration is calculated for the string with its ends moving in a prescribed way. For a string moving in a constant axial speed and constrained by two fixed ends, a conserved quantity is proved to remain unchanged during three-dimensional vibration, while the string energy is not conserved. An approximate conserved quantity is derived from the conserved quantity in the neighborhood of the straight equilibrium configuration. The approximate conserved quantity is applied to verify the Lyapunov stability of the straight equilibrium configuration. Numerical simulations are performed for a rubber string and a steel string. The results demonstrate the variation of the total mechanical energy and the invariance of the conserved quantity.

  7. A Wire Position Monitor System for the 1.3 FHZ Tesla-Style Cryomodule at the Fermilab New-Muon-Lab Accelerator

    SciTech Connect

    Eddy, N.; Fellenz, B.; Prieto, P.; Semenov, A.; Voy, D.C.; Wendt, M.; /Fermilab

    2011-08-17

    The first cryomodule for the beam test facility at the Fermilab New-Muon-Lab building is currently under RF commissioning. Among other diagnostics systems, the transverse position of the helium gas return pipe with the connected 1.3 GHz SRF accelerating cavities is measured along the {approx}15 m long module using a stretched-wire position monitoring system. An overview of the wire position monitor system technology is given, along with preliminary results taken at the initial module cooldown, and during further testing. As the measurement system offers a high resolution, we also discuss options for use as a vibration detector. An electron beam test facility, based on superconducting RF (SRF) TESLA-style cryomodules is currently under construction at the Fermilab New-Muon-Lab (NML) building. The first, so-called type III+, cryomodule (CM-1), equipped with eight 1.3 GHz nine-cell accelerating cavities was recently cooled down to 2 K, and is currently under RF conditioning. The transverse alignment of the cavity string within the cryomodule is crucial for minimizing transverse kick and beam break-up effects, generated by the high-order dipole modes of misaligned accelerating structures. An optimum alignment can only be guaranteed during the assembly of the cavity string, i.e. at room temperatures. The final position of the cavities after cooldown is uncontrollable, and therefore unknown. A wire position monitoring system (WPM) can help to understand the transverse motion of the cavities during cooldown, their final location and the long term position stability after cryo-temperatures are settled, as well as the position reproducibility for several cold-warm cycles. It also may serve as vibration sensor, as the wire acts as a high-Q resonant detector for mechanical vibrations in the low-audio frequency range. The WPM system consists out of a stretched-wire position detection system, provided with help of INFN-Milano and DESY Hamburg, and RF generation and read

  8. RADIATION PROTECTION SYSTEM INSTALLATION FOR THE ACCELERATOR PRODUCTION OF TRITIUM/LOW ENERGY DEMONSTRATION ACCELERATOR PROJECT (APT/LEDA)

    SciTech Connect

    J. WILMARTH; M. SMITH; T. TOMEI

    1999-07-01

    The APT/LEDA personnel radiation protection system installation was accomplished using a flexible, modular proven system which satisfied regulatory orders, project design criteria, operational modes, and facility requirements. The goal of providing exclusion and safe access of personnel to areas where prompt radiation in the LEDA facility is produced was achieved with the installation of a DOE-approved Personnel Access Control System (PACS). To satisfy the facility configuration design, the PACS, a major component of the overall radiation safety system, conveniently provided five independent areas of personnel access control. Because of its flexibility and adaptability the Los Alamos Neutron Science Center (LANSCE) designed Radiation Security System (RSS) was efficiently configured to provide the desired operational modes and satisfy the APT/LEDA project design criteria. The Backbone Beam Enable (BBE) system based on the LANSCE RSS provided the accelerator beam control functions with redundant, hardwired, tamper-resistant hardware. The installation was accomplished using modular components.

  9. Compact Superconducting Radio-frequency Accelerators and Innovative RF Systems

    SciTech Connect

    Kephart, Robert; Chattopadhyay, Swaapan; Milton, Stephen

    2015-04-10

    We will present several new technical and design breakthroughs that enable the creation of a new class of compact linear electron accelerators for industrial purposes. Use of Superconducting Radio-Frequency (SRF) cavities allow accelerators less than 1.5 M in length to create electron beams beyond 10 MeV and with average beam powers measured in 10’s of KW. These machines can have the capability to vary the output energy dynamically to produce brehmstrahlung x-rays of varying spectral coverage for applications such as rapid scanning of moving cargo for security purposes. Such compact accelerators will also be cost effective for many existing and new industrial applications. Examples include radiation crosslinking of plastics and rubbers, creation of pure materials with surface properties radically altered from the bulk, modification of bulk or surface optical properties of materials, sterilization of medical instruments animal solid or liquid waste, and destruction of organic compounds in industrial waste water effluents. Small enough to be located on a mobile platform, such accelerators will enable new remediation methods for chemical and biological spills and/or in-situ crosslinking of materials. We will describe one current design under development at Fermilab including plans for prototype and value-engineering to reduce costs. We will also describe development of new nano-structured field-emitter arrays as sources of electrons, new methods for fabricating and cooling superconducting RF cavities, and a new novel RF power source based on magnetrons with full phase and amplitude control.

  10. Ram accelerator direct launch system for space cargo

    NASA Technical Reports Server (NTRS)

    Bruckner, A. P.; Hertzberg, A.

    1987-01-01

    The ram accelerator, a chemically-propelled mass driver, is presented as a new approach for directly launching acceleration-insensitive pay-loads into LEO. The cargo vehicle resembles the centerbody of a conventional ramjet and travels through a launch tube filled with a premixed gaseous fuel and oxidizer mixture. The tube acts as the outer cowling of the ramjet and the combustion process travels with the vehicle. Two modes of ram accelerator drive are described, which when used in sequence, are capable of accelerating the cargo vehicle to 10 km/sec. The requirements for placing a 2000 kg vehicle with 50 percent payload fraction into a 400 km orbit, with a minimum of on-board rocket propellant for circularization maneuvers, are examined. It is shown that aerodynamic heating during atmospheric transit results in very little ablation of the nose. Both direct and indirect orbital insertion scenarios are investigated, and a three-step maneuver consisting of two burns and aerobraking is found to minimize the on-board propellant mass. A scenario involving a parking orbit below the desired final orbit is suggested as a means to increase the flexibility of the mass launch concept.

  11. Low-cost tape system measures velocity of acceleration

    NASA Technical Reports Server (NTRS)

    Hartenstein, R.

    1964-01-01

    By affixing perforated magnetic recording tape to the falling end of a body, acceleration and velocity were measured. The measurement was made by allowing the tape to pass between a light source and a photoelectric sensor. Data was obtained from a readout device.

  12. A Support System for Motion Training Using Motion Capture and Acceleration Sensors

    NASA Astrophysics Data System (ADS)

    Hayashi, Takahiro; Onai, Rikio

    This paper presents a support system for motion training for dances, sports, gestures, etc. In our previous study, we developed a prototype system for supporting motion training using motion caputure, i.e., marker tracking using a DV camera. The prototype system scores a user's motion by comparing tracking data of the user and a model with DP matching. The prototype system has a limit that it cannot accurately obtain acceleration of each part of the body because marker tracking using a DV camera cannot obtain three dimensional motion. By this limit, two different motions sometimes cannot be distinguished. For more effective motion training, in this study, we propose a system combining motion capture and acceleration sensors. We have examined the effectiveness of using acceleration sensors in motion training by comparing the proposed system with the prototype system. Experimental results have shown that two different motions can be more clearly distinguished by using the acceleration sensors.

  13. M-Strings

    NASA Astrophysics Data System (ADS)

    Haghighat, Babak; Iqbal, Amer; Kozçaz, Can; Lockhart, Guglielmo; Vafa, Cumrun

    2015-03-01

    M2 branes suspended between adjacent parallel M5 branes lead to light strings, the `M-strings'. In this paper we compute the elliptic genus of M-strings, twisted by maximally allowed symmetries that preserve 2 d (2, 0) supersymmetry. In a codimension one subspace of parameters this reduces to the elliptic genus of the (4, 4) supersymmetric A n-1 quiver theory in 2 d. We contrast the elliptic genus of N M-strings with the (4, 4) sigma model on the N-fold symmetric product of . For N = 1 they are the same, but for N > 1 they are close, but not identical. Instead the elliptic genus of (4, 4) N M-strings is the same as the elliptic genus of (4, 0) sigma models on the N-fold symmetric product of , but where the right-moving fermions couple to a modification of the tangent bundle. This construction arises from a dual A n-1 quiver 6 d gauge theory with U(1) gauge groups. Moreover, we compute the elliptic genus of domain walls which separate different numbers of M2 branes on the two sides of the wall.

  14. PT-symmetric strings

    SciTech Connect

    Amore, Paolo; Fernández, Francisco M.; Garcia, Javier; Gutierrez, German

    2014-04-15

    We study both analytically and numerically the spectrum of inhomogeneous strings with PT-symmetric density. We discuss an exactly solvable model of PT-symmetric string which is isospectral to the uniform string; for more general strings, we calculate exactly the sum rules Z(p)≡∑{sub n=1}{sup ∞}1/E{sub n}{sup p}, with p=1,2,… and find explicit expressions which can be used to obtain bounds on the lowest eigenvalue. A detailed numerical calculation is carried out for two non-solvable models depending on a parameter, obtaining precise estimates of the critical values where pair of real eigenvalues become complex. -- Highlights: •PT-symmetric Hamiltonians exhibit real eigenvalues when PT symmetry is unbroken. •We study PT-symmetric strings with complex density. •They exhibit regions of unbroken PT symmetry. •We calculate the critical parameters at the boundaries of those regions. •There are exact real sum rules for some particular complex densities.

  15. Topics in string theory

    SciTech Connect

    Liu, J.

    1988-01-01

    The author discusses several aspects of string theory. First, he calculates the vacuum amplitude of un-oriented open and closed string theory using Polyakov formalism. He argues that the volume of the Mobius Group should be renormalized, and solve a minor paradox. Second, he gives an example of a membrane whose effective action is the generalization of Green-Schwarz covariant superstring action. As a by-product, he shows that is also provides an example of partially broken global supersymmetry. The rest of the dissertation is devoted to the study of string field theory in terms of the renormalization group approach. He emphasizes the pivotal role of the conformal invariance in string theory. He proposes the generalized Wilsonian conformal renormalization group equation of 2-dimensional quantum field theory as the field equation for string field theory following Banks and Martinec. He then finds general solutions to the linearized equation on the flat back-ground and its correspondence to all the physical vertex operators. He also makes detailed study of massless modes and offer some remarks about how gauge invariance arise in this approach. Finally, he solves the full nonlinear equation iteratively in terms of the solutions to the linearized equation and extract the Virasoro-Shapiro amplitudes from them.

  16. Radition safety systems at Brookhaven National Laboratory's low-energy accelerators

    SciTech Connect

    Flood, Jr, C W

    1982-01-01

    Brookhaven National Laboratory has several low-energy accelerators in use at the present time. I intend to discuss the radiation safety systems installed at five of these accelerators. The accelerators included are a Dynamitron, 3.5 MeV Van de Graaff, 60'' Cyclotron, 41'' Cyclotron and Tandem Van de Graaff facility. All of these accelerators are capable of producing radiation levels in excess of 100 rem/h and the radiation safety systems are designed to prevent personnel from being exposed to high levels of radiation. For the purposes of this talk I would like to place the accelerators in two different categories. In the first category are the accelerators which have safety systems that prevent operation unless the radiation facilities are completely enclosed and interlocked, thus preventing any personnel access. Included are the Dynamitron, the 60'' Cyclotron, and the 41'' Cyclotron. In the second category are the accelerators with safety systems which allow access to any part of the accelerator facility when the radiation levels are low, but require complete personnel restrictions when the radiation levels are high. Included are the 3.5 MeV Van de Graaff and the Tandem Van de Graaff.

  17. Nuclear Effects of Supernova-Accelerated Cosmic Rays on Early Solar System Planetary Bodies

    NASA Astrophysics Data System (ADS)

    Meyer, B. S.; The, L.-S.; Johnson, J.

    2008-03-01

    The solar system apparently formed in the neighborhood of massive stars. Supernova explosions of these stars accelerate cosmic rays to 100s of TeVs. These cosmic rays could accelerate the beta decay of certain radioactive species in meteorite parent bodies.

  18. 49 CFR 571.124 - Standard No. 124; Accelerator control systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... the driver removes the actuating force from the accelerator control, or in the event of a severance or... and injuries resulting from engine overspeed caused by malfunctions in the accelerator control system. S3. Application. This standard applies to passenger cars, multi-purpose passenger vehicles,...

  19. AT2 DS II - Accelerator System Design (Part II) - CCC Video Conference

    ScienceCinema

    None

    2016-07-12

    Discussion Session - Accelerator System Design (Part II) Tutors: C. Darve, J. Weisend II, Ph. Lebrun, A. Dabrowski, U. Raich Video Conference with the CERN Control Center. Experts in the field of Accelerator science will be available to answer the students questions. This session will link the CCC and SA (using Codec VC).

  20. AT2 DS II - Accelerator System Design (Part II) - CCC Video Conference

    SciTech Connect

    2010-12-17

    Discussion Session - Accelerator System Design (Part II) Tutors: C. Darve, J. Weisend II, Ph. Lebrun, A. Dabrowski, U. Raich Video Conference with the CERN Control Center. Experts in the field of Accelerator science will be available to answer the students questions. This session will link the CCC and SA (using Codec VC).

  1. String radiative backreaction

    SciTech Connect

    Battye, R.A.; Shellard, E.P. |

    1995-12-01

    We discuss radiative backreaction for global strings described by the Kalb-Ramond action with an analogous derivation to that for the point electron in classical electrodynamics. We show how local corrections to the equations of motion allow one to separate the self-field of the string from that of the radiation field. Modifications to this {open_quote}{open_quote}local backreaction approximation{close_quote}{close_quote} circumvent the runaway solutions, allowing these corrections to be used to evolve string trajectories numerically. Comparisons are made with analytic and numerical radiation calculations from previous work and the merits and limitations of this approach are discussed. {copyright} {ital 1995 The American Physical Society.}

  2. Ram acceleration from a two phase detonative system

    NASA Technical Reports Server (NTRS)

    Cambier, Jean-Luc; Bogdanoff, David W.

    1993-01-01

    A concept for ram acceleration is presented here, which uses a combination of a gas core and a layer of solid explosive or propellant to generate high thrust densities. The concept can be either self-synchronized or externally synchronized, and may be reusable. It has the potential to achieve very high acceleration rates, higher exit velocities and to lower the tube length requirements. Preliminary numerical simulations are presented and discussed, which show the characteristics of the flow fields. Stable conditions can be achieved for low mass loadings of solid explosive, and relatively slow combustion. Accurate knowledge of the thermo-chemical properties and the equations of state of the gas and solid components is essential for further tuning of the concept.

  3. Tensionless strings from worldsheet symmetries

    NASA Astrophysics Data System (ADS)

    Bagchi, Arjun; Chakrabortty, Shankhadeep; Parekh, Pulastya

    2016-01-01

    We revisit the construction of the tensionless limit of closed bosonic string theory in the covariant formulation in the light of Galilean conformal symmetry that rises as the residual gauge symmetry on the tensionless worldsheet. We relate the analysis of the fundamentally tensionless theory to the tensionless limit that is viewed as a contraction of worldsheet coordinates. Analysis of the quantum regime uncovers interesting physics. The degrees of freedom that appear in the tensionless string are fundamentally different from the usual string states. Through a Bogoliubov transformation on the worldsheet, we link the tensionless vacuum to the usual tensile vacuum. As an application, we show that our analysis can be used to understand physics of strings at very high temperatures and propose that these new degrees of freedom are naturally connected with the long-string picture of the Hagedorn phase of free string theory. We also show that tensionless closed strings behave like open strings.

  4. Probing the String Landscape

    ScienceCinema

    Keith Dienes

    2016-07-12

    We are currently in the throes of a potentially huge paradigm shift in physics. Motivated by recent developments in string theory and the discovery of the so-called "string landscape", physicists are beginning to question the uniqueness of fundamental theories of physics and the methods by which such theories might be understood and investigated. In this colloquium, I will give a non-technical introduction to the nature of this paradigm shift and how it developed. I will also discuss some of the questions to which it has led, and the nature of the controversies it has spawned.

  5. Probing the String Landscape

    SciTech Connect

    Keith Dienes

    2009-12-01

    We are currently in the throes of a potentially huge paradigm shift in physics. Motivated by recent developments in string theory and the discovery of the so-called "string landscape", physicists are beginning to question the uniqueness of fundamental theories of physics and the methods by which such theories might be understood and investigated. In this colloquium, I will give a non-technical introduction to the nature of this paradigm shift and how it developed. I will also discuss some of the questions to which it has led, and the nature of the controversies it has spawned.

  6. Cosmic strings and galaxy formation

    NASA Technical Reports Server (NTRS)

    Bertschinger, Edmund

    1989-01-01

    The cosmogonical model proposed by Zel'dovich and Vilenkin (1981), in which superconducting cosmic strings act as seeds for the origin of structure in the universe, is discussed, summarizing the results of recent theoretical investigations. Consideration is given to the formation of cosmic strings, the microscopic structure of strings, gravitational effects, cosmic string evolution, and the formation of galaxies and large-scale structure. Simulation results are presented in graphs, and several outstanding issues are listed and briefly characterized.

  7. Ion extraction capabilities of two-grid accelerator systems. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Rovang, D. C.; Wilbur, P. J.

    1984-01-01

    An experimental investigation into the ion extraction capabilities of two-grid accelerator systems common to electrostatic ion thrusters is described. This work resulted in a large body of experimental data which facilitates the selection of the accelerator system geometries and operating parameters necessary to maximize the extracted ion current. Results suggest that the impingement-limited perveance is not dramatically affected by reductions in screen hole diameter to 0.5 mm. Impingement-limited performance is shown to depend most strongly on grid separation distance, accelerator hole diameter ratio, the discharge-to-total accelerating voltage ratio, and the net-to-total accelerating voltage ratio. Results obtained at small grid separation ratios suggest a new grid operating condition where high beam current per hole levels are achieved at a specified net accelerating voltage. It is shown that this operating condition is realized at an optimum ratio of net-to-total accelerating voltage ratio which is typically quite high. The apparatus developed for this study is also shown to be well suited measuring the electron backstreaming and electrical breakdown characteristics of two-grid accelerator systems.

  8. Characterization of ion accelerating systems on NASA LeRC's ion thrusters

    NASA Technical Reports Server (NTRS)

    Rawlin, Vincent K.

    1992-01-01

    An investigation is conducted regarding ion-accelerating systems for two NASA thrusters to study the limits of ion-extraction capability or perveance. A total of nine two-grid ion-accelerating systems are tested with the 30- and 50-cm-diam ring-cusp inert-gas ion thrusters emphasizing the extension of ion-extraction. The vacuum-tank testing is described using xenon, krypton, and argon propellants, and thruster performance is computed with attention given to theoretical design considerations. Reductions in perveance are noted with decreasing accelerator-hole-to-screen-hole diameter ratios. Perveance values vary indirectly with the ratio of discharge voltage to total accelerating voltage, and screen/accelerator electrode hole-pair alignment is also found to contribute to perveance values.

  9. Embellished String Prints. Cover Story.

    ERIC Educational Resources Information Center

    Smith, Mary Ruth

    1999-01-01

    Focuses on a printmaking activity in which students create embellished string prints using the relief process of string glued to chip board. Explains that string prints can easily be embellished with oil pastels. Provides a description of the procedure and a list of materials and methods. (CMK)

  10. String Theory and Gauge Theories

    SciTech Connect

    Maldacena, Juan

    2009-02-20

    We will see how gauge theories, in the limit that the number of colors is large, give string theories. We will discuss some examples of particular gauge theories where the corresponding string theory is known precisely, starting with the case of the maximally supersymmetric theory in four dimensions which corresponds to ten dimensional string theory. We will discuss recent developments in this area.

  11. Application of JLab 12GeV helium refrigeration system for the FRIB accelerator at MSU

    SciTech Connect

    Ganni, Venkatarao; Knudsen, Peter N.; Arenius, Dana M.; Casagrande, Fabio

    2014-01-01

    The planned approach to have a turnkey helium refrigeration system for the MSU-FRIB accelerator system, encompassing the design, fabrication, installation and commissioning of the 4.5-K refrigerator cold box(es), cold compression system, warm compression system, gas management, oil removal and utility/ancillary systems, was found to be cost prohibitive. Following JLab’s suggestion, MSU-FRIB accelerator management made a formal request to evaluate the applicability of the recently designed 12GeV JLab cryogenic system for this application. The following paper will outline the findings and the planned approach for the FRIB helium refrigeration system.

  12. Application of JLab 12GeV helium refrigeration system for the FRIB accelerator at MSU

    SciTech Connect

    Ganni, V.; Knudsen, P.; Arenius, D.; Casagrande, F.

    2014-01-29

    The planned approach to have a turnkey helium refrigeration system for the MSU-FRIB accelerator system, encompassing the design, fabrication, installation and commissioning of the 4.5-K refrigerator cold box(es), cold compression system, warm compression system, gas management, oil removal and utility/ancillary systems, was found to be cost prohibitive. Following JLab’s suggestion, MSU-FRIB accelerator management made a formal request to evaluate the applicability of the recently designed 12GeV JLab cryogenic system for this application. The following paper will outline the findings and the planned approach for the FRIB helium refrigeration system.

  13. Optimization of accelerator system performance at the NSLS

    SciTech Connect

    Krinsky, S.

    1994-10-01

    There is an active program of accelerator development at the NSLS aimed at improving reliability, stability and brightness. Work is primarily focused on providing improved performance for the NSLS user community, however, important elements of our work have a generic character and should be of value to other synchrotron radiation facilities. In particular, we have successfully operated a small gap undulator with a full vertical beam aperture of only 3.8 mm, with no degradation of beam lifetime. This provides strong support for the belief that small gap, short period devices will play an important role in the future.

  14. Revisiting noninteracting string partition functions in Rindler space

    NASA Astrophysics Data System (ADS)

    Mertens, Thomas G.; Verschelde, Henri; Zakharov, Valentin I.

    2016-05-01

    We revisit noninteracting string partition functions in Rindler space by summing over fields in the spectrum. In field theory, the total partition function splits in a natural way into a piece that does not contain surface terms and a piece consisting of solely the so-called edge states. For open strings, we illustrate that surface contributions to the higher-spin fields correspond to open strings piercing the Rindler origin, unifying the higher-spin surface contributions in string language. For closed strings, we demonstrate that the string partition function is not quite the same as the sum over the partition functions of the fields in the spectrum: an infinite overcounting is present for the latter. Next we study the partition functions obtained by excluding the surface terms. Using recent results of He et al. [J. High Energy Phys. 05 (2015) 106], this construction, first done by Emparan [arXiv:hep-th/9412003], can be put on much firmer ground. We generalize to type II and heterotic superstrings and demonstrate modular invariance. All of these exhibit an IR divergence that can be interpreted as a maximal acceleration close to the black hole horizon. Ultimately, since these partition functions are only part of the full story, divergences here should not be viewed as a failure of string theory: maximal acceleration is a feature of a faulty treatment of the higher-spin fields in the string spectrum. We comment on the relevance of this to Solodukhin's recent proposal [Phys. Rev. D 91, 084028 (2015)]. A possible link with the firewall paradox is apparent.

  15. Bunching in time at the ATLAS (Argonne Tandem-Linac Accelerator System) accelerator

    SciTech Connect

    Pardo, R.

    1986-01-01

    The ability to manipulate the energy spread and time width of the beam from the ATLAS linac is an important feature used by the experimental program at Argonne. The time resolution which can be obtained on target has been shown to be less than 150 ps. for all beams through /sup 58/Ni. The fundamental ideas which apply to the bunching of heavy ion beams are described and the limitations and capabilities of the bunching system are discussed. A sequential guide for obtaining good timing on target is included.

  16. String Cosmology: A Review

    SciTech Connect

    McAllister, Liam P.; Silverstein, Eva

    2007-10-22

    We give an overview of the status of string cosmology. We explain the motivation for the subject, outline the main problems, and assess some of the proposed solutions. Our focus is on those aspects of cosmology that benefit from the structure of an ultraviolet-complete theory.

  17. Experimenting with Guitar Strings

    NASA Astrophysics Data System (ADS)

    LoPresto, Michael C.

    2006-11-01

    What follows is a description of a simple experiment developed in a nonmathematical general education science course on sound and light for fine arts students in which a guitar is used with data collection hardware and software to verify the properties of standing waves on a string.

  18. Experimenting with Guitar Strings

    ERIC Educational Resources Information Center

    LoPresto, Michael C.

    2006-01-01

    What follows is a description of a simple experiment developed in a non-mathematical general education science course on sound and light for fine arts students in which a guitar is used with data collection hardware and software to verify the properties of standing waves on a string.

  19. Exotic nonrelativistic string

    SciTech Connect

    Casalbuoni, Roberto; Gomis, Joaquim; Longhi, Giorgio

    2007-12-15

    We construct a classical nonrelativistic string model in 3+1 dimensions. The model contains a spurion tensor field that is responsible for the noncommutative structure of the model. Under double-dimensional reduction the model reduces to the exotic nonrelativistic particle in 2+1 dimensions.

  20. A Vibrating String Experiment

    ERIC Educational Resources Information Center

    Tsutsumanova, Gichka; Russev, Stoyan

    2013-01-01

    A simple experiment demonstrating the excitation of a standing wave in a metal string is presented here. Several tasks using the set-up are considered, which help the students to better understand the standing waves, the interaction between electric current and magnetic field and the resonance phenomena. This can serve also as a good lecture…

  1. Strings in four dimensions

    SciTech Connect

    Bachas, C.P.

    1988-01-01

    We review the construction and properties of four dimensional string models, using free fermions on the world-sheet. We prove that as opposed to gauge symmetries, broken space-time supersymmetry can only be restored continuously by decompactification. 40 refs.

  2. Gravity and Strings

    NASA Astrophysics Data System (ADS)

    Ortín, Tomás

    2015-03-01

    1. Differential geometry; 2. Symmetries and Noether's theorems; 3. A perturbative introduction to general relativity; 4. Action principles for gravity; 5. Pure N=1,2,d=4 supergravities; 6. Matter-coupled N=1,d=4 supergravity; 7. Matter-coupled N=2,d=4 supergravity; 8. A generic description of all the N>2,d=4 SUEGRAS; 9. Matter-coupled N=1,d=5 supergravity; 10. Conserved charges in general relativity; 11. The Schwarzschild black hole; 12. The Reissner-Nordström black hole; 13. The Taub-NUT solution; 14. Gravitational pp-waves; 15. The Kaluza-Klein black hole; 16. Dilaton and dilaton/axion black holes; 17. Unbroken supersymmetry I: supersymmetric vacua; 18. Unbroken supersymmetry II: partially supersymmetric solutions; 19. Supersymmetric black holes from supergravity; 20. String theory; 21. The string effective action and T duality; 22. From eleven to four dimensions; 23. The type-IIB superstring and type-II T duality; 24. Extended objects; 25. The extended objects of string theory; 26. String black holes in four and five dimensions; 27. The FGK formalism for (single, static) black holes and branes; Appendices: A.1 Lie groups, symmetric spaces, and Yang-Mills fields; A.2 The irreducible, non-symmetric Riemannian spaces of special holonomy; A.3 Miscellanea on the symplectic group; A.4 Gamma matrices and spinors; A.5 Kähler geometry; A.6 Special Kähler geometry; A.7 Quaternionic-Kähler geometry.

  3. SIRIUS - A new 6 MV accelerator system for IBA and AMS at ANSTO

    NASA Astrophysics Data System (ADS)

    Pastuovic, Zeljko; Button, David; Cohen, David; Fink, David; Garton, David; Hotchkis, Michael; Ionescu, Mihail; Long, Shane; Levchenko, Vladimir; Mann, Michael; Siegele, Rainer; Smith, Andrew; Wilcken, Klaus

    2016-03-01

    The Centre for Accelerator Science (CAS) facility at ANSTO has been expanded with a new 6 MV tandem accelerator system supplied by the National Electrostatic Corporation (NEC). The beamlines, end-stations and data acquisition software for the accelerator mass spectrometry (AMS) were custom built by NEC for rare isotope mass spectrometry, while the beamlines with end-stations for the ion beam analysis (IBA) are largely custom designed at ANSTO. An overview of the 6 MV system and its performance during testing and commissioning phase is given with emphasis on the IBA end-stations and their applications for materials modification and characterisation.

  4. Advanced Klystrons for High Efficiency Accelerator Systems - Final Report

    SciTech Connect

    Read, Michael; Ives, Robert Lawrence

    2014-03-26

    This program explored tailoring of RF pulses used to drive accelerator cavities. Simulations indicated that properly shaping the pulse risetime to match accelerator cavity characteristics reduced reflected power and increased total efficiency. Tailoring the pulse requires a high power, gridded, klystron to shape the risetime while also controlling the beam current. The Phase I program generated a preliminary design of a gridded electron gun for a klystron producing 5-10 MW of RF power. This required design of a segmented cathode using Controlled Porosity Reservoir cathodes to limit power deposition on the grid. The program was successful in computationally designing a gun producing a high quality electron beam with grid control. Additional analysis of pulse tailoring indicated that technique would only be useful for cavity drive pulses that were less than approximately 2-3 times the risetime. Otherwise, the efficiency gained during the risetime of the pulse became insignificant when considering the efficiency over the entire pulse. Consequently, it was determined that a Phase II program would not provide sufficient return to justify the cost. Never the less, other applications for a high power gridded gun are currently being pursued. This klystron, for example, would facilitate development inverse Comptom x-ray sources by providing a high repetition rate (10 -100 kHz) RF source.

  5. Los Alamos Neutron Science Center (LANSCE) accelerator timing system upgrade

    SciTech Connect

    Rybarcyk, L.J.; Shelley, F.E. Jr.

    1997-10-01

    The Los Alamos Neutron Science Center (LANSCE) 800 MeV proton linear accelerator (linac) operates at a maximum repetition rate of twice the AC power line frequency, i.e. 120 Hz. The start of each machine cycle occurs a fixed delay after each zero-crossing of the AC line voltage. Fluctuations in the AC line frequency and phase are therefore present on all linac timing signals. Proper beam acceleration along the linac requires that the timing signals remain well synchronized to the AC line. For neutron chopper spectrometers, e.g., PHAROS at the Manuel Lujan Jr. Neutron Scattering Center, accurate neutron energy selection requires that precise synchronization be maintained between the beam-on-target arrival time and the neutron chopper rotor position. This is most easily accomplished when the chopper is synchronized to a stable, fixed frequency signal. A new zero-crossing circuit which employs a Phase-Locked Loop (PLL) has been developed to increase the phase and frequency stability of the linac timing signals and thereby improve neutron chopper performance while simultaneously maintaining proper linac operation. Results of timing signal data analysis and modeling and a description of the PLL circuit are presented.

  6. Power-conditioning system for the Advanced Test Accelerator

    SciTech Connect

    Newton, M.A.; Smith, M.E.; Birx, D.L.; Branum, D.R.; Cook, E.G.; Copp, R.L.; Lee, F.D.; Reginato, L.L.; Rogers, D.; Speckert, G.C.

    1982-06-01

    The Advanced Test Accelerator (ATA) is a pulsed, linear induction, electron accelerator currently under construction and nearing completion at Lawrence Livermore National Laboratory's Site 300 near Livermore, California. The ATA is a 50 MeV, 10 kA machine capable of generating electron beam pulses at a 1 kHz rate in a 10 pulse burst, 5 pps average, with a pulse width of 70 ns FWHM. Ten 18 kV power supplies are used to charge 25 capacitor banks with a total energy storage of 8 megajoules. Energy is transferred from the capacitor banks in 500 microsecond pulses through 25 Command Resonant Charge units (CRC) to 233 Thyratron Switch Chassis. Each Thyratron Switch Chassis contains a 2.5 microfarad capacitor and is charged to 25 kV (780 joules) with voltage regulation of +- .05%. These capacitors are switched into 10:1 step-up resonant transformers to charge 233 Blumleins to 250 kV in 20 microseconds. A magnetic modulator is used instead of a Blumlein to drive the grid of the injector.

  7. Disposition of nuclear waste using subcritical accelerator-driven systems

    SciTech Connect

    Venneri, F.; Li, N.; Williamson, M.; Houts, M.; Lawrence, G.

    1998-12-31

    Spent fuel from nuclear power plants contains large quantities of Pu, other actinides, and fission products (FP). This creates challenges for permanent disposal because of the long half-lives of some isotopes and the potential for diversion of the fissile material. Two issues of concern for the US repository concept are: (1) long-term radiological risk peaking tens-of-thousands of years in the future; and (2) short-term thermal loading (decay heat) that limits capacity. An accelerator-driven neutron source can destroy actinides through fission, and can convert long-lived fission products to shorter-lived or stable isotopes. Studies over the past decade have established that accelerator transmutation of waste (ATW) can have a major beneficial impact on the nuclear waste problem. Specifically, the ATW concept the authors are evaluating: (1) destroys over 99.9% of the actinides; (2) destroys over 99.9% of the Tc and I; (3) separates Sr-90 and Cs-137; (4) separates uranium from the spent fuel; (5) produces electric power.

  8. Evolution of cosmic string networks

    NASA Technical Reports Server (NTRS)

    Albrecht, Andreas; Turok, Neil

    1989-01-01

    A discussion of the evolution and observable consequences of a network of cosmic strings is given. A simple model for the evolution of the string network is presented, and related to the statistical mechanics of string networks. The model predicts the long string density throughout the history of the universe from a single parameter, which researchers calculate in radiation era simulations. The statistical mechanics arguments indicate a particular thermal form for the spectrum of loops chopped off the network. Detailed numerical simulations of string networks in expanding backgrounds are performed to test the model. Consequences for large scale structure, the microwave and gravity wave backgrounds, nucleosynthesis and gravitational lensing are calculated.

  9. Current balancing for battery strings

    DOEpatents

    Galloway, James H.

    1985-01-01

    A battery plant is described which features magnetic circuit means for balancing the electrical current flow through a pluraliircuitbattery strings which are connected electrically in parallel. The magnetic circuit means is associated with the battery strings such that the conductors carrying the electrical current flow through each of the battery strings pass through the magnetic circuit means in directions which cause the electromagnetic fields of at least one predetermined pair of the conductors to oppose each other. In an alternative embodiment, a low voltage converter is associated with each of the battery strings for balancing the electrical current flow through the battery strings.

  10. Method for Direct Measurement of Cosmic Acceleration by 21-cm Absorption Systems

    NASA Astrophysics Data System (ADS)

    Yu, Hao-Ran; Zhang, Tong-Jie; Pen, Ue-Li

    2014-07-01

    So far there is only indirect evidence that the Universe is undergoing an accelerated expansion. The evidence for cosmic acceleration is based on the observation of different objects at different distances and requires invoking the Copernican cosmological principle and Einstein's equations of motion. We examine the direct observability using recession velocity drifts (Sandage-Loeb effect) of 21-cm hydrogen absorption systems in upcoming radio surveys. This measures the change in velocity of the same objects separated by a time interval and is a model-independent measure of acceleration. We forecast that for a CHIME-like survey with a decade time span, we can detect the acceleration of a ΛCDM universe with 5σ confidence. This acceleration test requires modest data analysis and storage changes from the normal processing and cannot be recovered retroactively.

  11. String theories and millisecond pulsars

    NASA Astrophysics Data System (ADS)

    Sanchez, N.; Signore, M.

    1988-11-01

    We discuss the two ways of connecting string theories (cosmic, fundamental and the connection between them) to the observational reality: (i) radioastronomy observations (millisecond pulsar timing), and (ii) elementary particle phenomenology (compactification schemes). We study the limits imposed on the string parameter Gμ by recent millisecond pulsar timings. Cosmic strings derived from GUTs agree with (i). For cosmic strings derived from fundamental strings themselves there is contradiction between (i) and (ii). One of these scenarios connecting string theory to reality must be revised (or the transition from fundamental into cosmic strings rejected). Meanwhile, millisecond pulsar can select one scenario, or reject both of them. UA 336 Laboratoire Associé au CNRS, Observatoire de Meudon et Ecole Normale Supérieure, 24 rue Lhomond, F-75231 Paris Cedex 05, France.

  12. Device for balancing parallel strings

    DOEpatents

    Mashikian, Matthew S.

    1985-01-01

    A battery plant is described which features magnetic circuit means in association with each of the battery strings in the battery plant for balancing the electrical current flow through the battery strings by equalizing the voltage across each of the battery strings. Each of the magnetic circuit means generally comprises means for sensing the electrical current flow through one of the battery strings, and a saturable reactor having a main winding connected electrically in series with the battery string, a bias winding connected to a source of alternating current and a control winding connected to a variable source of direct current controlled by the sensing means. Each of the battery strings is formed by a plurality of batteries connected electrically in series, and these battery strings are connected electrically in parallel across common bus conductors.

  13. String-merging of meso- viscoelastic droplets

    NASA Astrophysics Data System (ADS)

    Xu, Yuanze; Xu, Jianmao

    2007-03-01

    Great challenge exists in the multi-scale rheological modeling of immiscible polyblends with non-linear morphology changes, including viscoelastic drop break-up and collapse. A new type mechanism of merging and coalescence, called string-merging of meso- viscoelastic droplets was described and analyzed. By iterative stretching and relaxation in a four-roll mill rheometer, one droplet containing high molar mass PIB (polyisobutene), was separated into two droplets connected by a string in a dumbbell shape suspending in polydimethylsiloxane (PDMS) medium. In quiescent state, the string pulled the two spheres merging closer and collapsed into one spherical drop finally. The process exhibits interesting features, different from capillary breakup mechanism. By adding the viscoelasticity of the systems to the force balance of Laplace force and viscous drag, the phenomenon may be well analyzed. The necessity to involve the microscopic consideration of the highly oriented entangled state are discussed.

  14. Extending PowerPack for Profiling and Analysis of High Performance Accelerator-Based Systems

    SciTech Connect

    Li, Bo; Chang, Hung-Ching; Song, Shuaiwen; Su, Chun-Yi; Meyer, Timmy; Mooring, John; Cameron, Kirk

    2014-12-01

    Accelerators offer a substantial increase in efficiency for high-performance systems offering speedups for computational applications that leverage hardware support for highly-parallel codes. However, the power use of some accelerators exceeds 200 watts at idle which means use at exascale comes at a significant increase in power at a time when we face a power ceiling of about 20 megawatts. Despite the growing domination of accelerator-based systems in the Top500 and Green500 lists of fastest and most efficient supercomputers, there are few detailed studies comparing the power and energy use of common accelerators. In this work, we conduct detailed experimental studies of the power usage and distribution of Xeon-Phi-based systems in comparison to the NVIDIA Tesla and at SandyBridge.

  15. About the scheme of the infrared FEL system for the accelerator based on HF wells

    SciTech Connect

    Kabanov, V.S.; Dzergach, A.I.

    1995-12-31

    Accelerators, based on localization of plasmoids in the HF wells (RF traps) of the axially-symmetric electromagnetic field E {sub omn} in an oversized (m,n>>1) resonant system, can give accelerating gradients {approximately}100 kV/{lambda}, e.g. 10 GV/m if {lambda}=10 {mu}m. One of possible variants of HF feeding for these accelerators is based on using the powerful infrared FEL System with 2 frequencies. The corresponding FEL`s may be similar to the Los Alamos compact Advanced FEL ({lambda}{sub 1,2}{approximately}10 pm, e-beam energy {approximately}15 MeV, e-beam current {approximately}100 A). Their power is defined mainly by the HF losses in the resonant system of the supposed accelerator.

  16. Chiral phase transition from string theory.

    PubMed

    Parnachev, Andrei; Sahakyan, David A

    2006-09-15

    The low energy dynamics of a certain D-brane configuration in string theory is described at weak t'Hooft coupling by a nonlocal version of the Nambu-Jona-Lasinio model. We study this system at finite temperature and strong t'Hooft coupling, using the string theory dual. We show that for sufficiently low temperatures chiral symmetry is broken, while for temperatures larger then the critical value, it gets restored. We compute the latent heat and observe that the phase transition is of the first order.

  17. Blackfolds in supergravity and string theory

    NASA Astrophysics Data System (ADS)

    Emparan, Roberto; Harmark, Troels; Niarchos, Vasilis; Obers, Niels A.

    2011-08-01

    We develop the effective worldvolume theory for the dynamics of black branes with charges of the kind that arise in many supergravities and low-energy limits of string theory. Using this theory, we construct numerous new rotating blackholes with charges and dipoles of D-branes, fundamental strings and other branes. In some instances, the black holes can be dynamically stable close enough to extremality. Some of these black holes, such as those based on the D1-D5-P system, have extremal, non-supersymmetric limits with regular horizons of finite area and a wide variety of horizon topologies and geometries.

  18. Non-linear stochastic optimal control of acceleration parametrically excited systems

    NASA Astrophysics Data System (ADS)

    Wang, Yong; Jin, Xiaoling; Huang, Zhilong

    2016-02-01

    Acceleration parametrical excitations have not been taken into account due to the lack of physical significance in macroscopic structures. The explosive development of microtechnology and nanotechnology, however, motivates the investigation of the acceleration parametrically excited systems. The adsorption and desorption effects dramatically change the mass of nano-sized structures, which significantly reduces the precision of nanoscale sensors or can be reasonably utilised to detect molecular mass. This manuscript proposes a non-linear stochastic optimal control strategy for stochastic systems with acceleration parametric excitation based on stochastic averaging of energy envelope and stochastic dynamic programming principle. System acceleration is approximately expressed as a function of system displacement in a short time range under the conditions of light damping and weak excitations, and the acceleration parametrically excited system is shown to be equivalent to a constructed system with an additional displacement parametric excitation term. Then, the controlled system is converted into a partially averaged Itô equation with respect to the total system energy through stochastic averaging of energy envelope, and the optimal control strategy for the averaged system is derived from solving the associated dynamic programming equation. Numerical results for a controlled Duffing oscillator indicate the efficacy of the proposed control strategy.

  19. Design and test of a superconducting magnet in a linear accelerator for an Accelerator Driven Subcritical System

    NASA Astrophysics Data System (ADS)

    Peng, Quanling; Xu, Fengyu; Wang, Ting; Yang, Xiangchen; Chen, Anbin; Wei, Xiaotao; Gao, Yao; Hou, Zhenhua; Wang, Bing; Chen, Yuan; Chen, Haoshu

    2014-11-01

    A batch superconducting solenoid magnet for the ADS proton linear accelerator has been designed, fabricated, and tested in a vertical dewar in Sept. 2013. A total of ten superconducting magnets will be installed into two separate cryomodules. Each cryomodule contains six superconducting spoke RF cavities for beam acceleration and five solenoid magnets for beam focusing. The multifunction superconducting magnet contains a solenoid for beam focusing and two correctors for orbit correction. The design current for the solenoid magnet is 182 A. A quench performance test shows that the operating current of the solenoid magnet can reach above 300 A after natural quenching on three occasions during current ramping (260 A, 268 A, 308 A). The integrated field strength and leakage field at the nearby superconducting spoke cavities all meet the design requirements. The vertical test checked the reliability of the test dewar and the quench detection system. This paper presents the physical and mechanical design of the batch magnets, the quench detection technique, field measurements, and a discussion of the residual field resulting from persistent current effects.

  20. Modeling and Commissioning of a Cold Compressor String for the Superfluid Cryogenic Plant at Fermilab's Cryo-module Test Facility

    NASA Astrophysics Data System (ADS)

    Ueresin, C.; Decker, L.; Treite, P.

    In 2011, Linde Cryogenics, a division of Linde Process Plants, Tulsa, Oklahoma, was awarded the contract to deliver a 500 W at 2 K superfluid cryogenic plant to Fermi National Accelerator Laboratory (FNAL) in Batavia, Illinois, USA. This system includes a cold compressor string with three centrifugal compressors and a vacuum pump skid with five volumetric pumps in parallel used to pump down helium to its saturation pressure corresponding to 2 K. Linde Kryotechnik AG, Pfungen Switzerland engineered and supplied the cold compressor system and commissioned it with its control logic to cover the complete range of system operation. The paper outlines issues regarding compressor design, compressor string modeling, control algorithms, controller performance, and surge protection.

  1. Regional systems of care demonstration project: Mission: Lifeline STEMI Systems Accelerator: design and methodology.

    PubMed

    Bagai, Akshay; Al-Khalidi, Hussein R; Sherwood, Matthew W; Muñoz, Daniel; Roettig, Mayme L; Jollis, James G; Granger, Christopher B

    2014-01-01

    ST-segment elevation myocardial infarction (STEMI) systems of care have been associated with significant improvement in use and timeliness of reperfusion. Consequently, national guidelines recommend that each community should develop a regional STEMI care system. However, significant barriers continue to impede widespread establishment of regional STEMI care systems in the United States. We designed the Regional Systems of Care Demonstration Project: Mission: Lifeline STEMI Systems Accelerator, a national educational outcome research study in collaboration with the American Heart Association, to comprehensively accelerate the implementation of STEMI care systems in 17 major metropolitan regions encompassing >1,500 emergency medical service agencies and 450 hospitals across the United States. The goals of the program are to identify regional gaps, barriers, and inefficiencies in STEMI care and to devise strategies to implement proven recommendations to enhance the quality and consistency of care. The study interventions, facilitated by national faculty with expertise in regional STEMI system organization in partnership with American Heart Association representatives, draw upon specific resources with proven past effectiveness in augmenting regional organization. These include bringing together leading regional health care providers and institutions to establish common commitment to STEMI care improvement, developing consensus-based standardized protocols in accordance with national professional guidelines to address local needs, and collecting and regularly reviewing regional data to identify areas for improvement. Interventions focus on each component of the reperfusion process: the emergency medical service, the emergency department, the catheterization laboratory, and inter-hospital transfer. The impact of regionalization of STEMI care on clinical outcomes will be evaluated.

  2. The vacuum system for the Munich fission fragment accelerator

    NASA Astrophysics Data System (ADS)

    Maier-Komor, P.; Faestermann, T.; Krücken, R.; Nebel, F.; Winkler, S.; Groß, M.; Habs, D.; Kester, O.; Szerypo, J.; Thirolf, P. G.

    2006-05-01

    The Munich Accelerator for Fission Fragments (MAFF) is a radioactive ion beam facility which will be installed at the new research reactor FRM-II. This new reactor became critical in Spring 2004. The heart of MAFF, the target-ion source unit will be placed in the through-going beam tube of the FRM-II. This beam tube has been installed, tested and filled with helium in 2001. The cogent authorization procedures and safety levels developed for nuclear power plants are applied for this research reactor also. Therefore, MAFF also has to obey these very strict rules, because the typical 1 g load of 235U in the MAFF source creates a fission product activity of several 10 14 Bq after one reactor cycle of 52 days. All vacuum components must withstand a pressure of 6×10 5 Pa in addition to their UHV acceptability. Even dynamic gaskets must be strictly metallic, because organic compounds would not withstand the radioactive irradiation during the design lifetime of 30 years. Only dry vacuum pumps are suitable: refrigerator cryopumps for the high-vacuum part and five stages of roots pumps for roughing and regeneration.

  3. System modeling for the longitudinal beam dynamics control problem in heavy ion induction accelerators

    SciTech Connect

    Payne, A.N.

    1993-05-17

    We address the problem of developing system models that are suitable for studying the control of the longitudinal beam dynamics in induction accelerators for heavy ions. In particular, we present the preliminary results of our efforts to devise a general framework for building detailed, integrated models of accelerator systems consisting of pulsed power modular circuits, induction cells, beam dynamics, and control system elements. Such a framework will permit us to analyze and design the pulsed power modulators and the control systems required to effect precise control over the longitudinal beam dynamics.

  4. Postmodern string theory: Stochastic formulation

    NASA Astrophysics Data System (ADS)

    Aurilia, A.; Spallucci, E.; Vanzetta, I.

    1994-11-01

    In this paper we study the dynamics of a statistical ensemble of strings, building on a recently proposed gauge theory of the string geodesic field. We show that this stochastic approach is equivalent to the Carathéodory formulation of the Nambu-Goto action, supplemented by an averaging procedure over the family of classical string world sheets which are solutions of the equation of motion. In this new framework, the string geodesic field is reinterpreted as the Gibbs current density associated with the string statistical ensemble. Next, we show that the classical field equations derived from the string gauge action can be obtained as the semiclassical limit of the string functional wave equation. For closed strings, the wave equation itself is completely analogous to the Wheeler-DeWitt equation used in quantum cosmology. Thus, in the string case, the wave function has support on the space of all possible spatial loop configurations. Finally, we show that the string distribution induces a multiphase, or cellular structure on the spacetime manifold characterized by domains with a purely Riemannian geometry separated by domain walls over which there exists a predominantly Weyl geometry.

  5. Engineered and Administrative Safety Systems for the Control of Prompt Radiation Hazards at Accelerator Facilities

    SciTech Connect

    Liu, James C.; Vylet, Vashek; Walker, Lawrence S.; /SLAC

    2007-12-17

    The ANSI N43.1 Standard, currently in revision (ANSI 2007), sets forth the requirements for accelerator facilities to provide adequate protection for the workers, the public and the environment from the hazards of ionizing radiation produced during and from accelerator operations. The Standard also recommends good practices that, when followed, provide a level of radiation protection consistent with those established for the accelerator communities. The N43.1 Standard is suitable for all accelerator facilities (using electron, positron, proton, or ion particle beams) capable of producing radiation, subject to federal or state regulations. The requirements (see word 'shall') and recommended practices (see word 'should') are prescribed in a graded approach that are commensurate with the complexity and hazard levels of the accelerator facility. Chapters 4, 5 and 6 of the N43.1 Standard address specially the Radiation Safety System (RSS), both engineered and administrative systems, to mitigate and control the prompt radiation hazards from accelerator operations. The RSS includes the Access Control System (ACS) and Radiation Control System (RCS). The main requirements and recommendations of the N43.1 Standard regarding the management, technical and operational aspects of the RSS are described and condensed in this report. Clearly some aspects of the RSS policies and practices at different facilities may differ in order to meet the practical needs for field implementation. A previous report (Liu et al. 2001a), which reviews and summarizes the RSS at five North American high-energy accelerator facilities, as well as the RSS references for the 5 labs (Drozdoff 2001; Gallegos 1996; Ipe and Liu 1992; Liu 1999; Liu 2001b; Rokni 1996; TJNAF 1994; Yotam et al. 1991), can be consulted for the actual RSS implementation at various laboratories. A comprehensive report describing the RSS at the Stanford Linear Accelerator Center (SLAC 2006) can also serve as a reference.

  6. Axions in String Theory

    SciTech Connect

    Svrcek, Peter; Witten, Edward; /Princeton, Inst. Advanced Study

    2006-06-09

    In the context of string theory, axions appear to provide the most plausible solution of the strong CP problem. However, as has been known for a long time, in many string-based models, the axion coupling parameter Fa is several orders of magnitude higher than the standard cosmological bounds. We re-examine this problem in a variety of models, showing that Fa is close to the GUT scale or above in many models that have GUT-like phenomenology, as well as some that do not. On the other hand, in some models with Standard Model gauge fields supported on vanishing cycles, it is possible for Fa to be well below the GUT scale.

  7. Wing on a String

    ERIC Educational Resources Information Center

    Fitzgerald, Mike; Brand, Lance

    2004-01-01

    In this article, the authors present an activity that shows students how flight occurs. The "wing on a string" is a simple teacher-made frame that consists of PVC pipe, fishing line, and rubber bands--all readily available hardware store items. The only other materials/tools involved are a sheet of paper, some pieces of a soda straw, a stapler,…

  8. Anyons from Strings

    SciTech Connect

    Mezincescu, Luca; Townsend, Paul K.

    2010-11-05

    The Nambu-Goto string in a three-dimensional (3D) Minkowski spacetime is quantized preserving Lorentz invariance and parity. The spectrum of massive states contains anyons. An ambiguity in the ground state energy is resolved by the 3D N=1 Green-Schwarz superstring, which has massless ground states describing a dilaton and dilatino, and first-excited states of spin 1/4.

  9. The Machine Protection System for the Fermilab Accelerator Science and Technology Facility

    SciTech Connect

    Wu, Jinyuan; Warner, Arden; Liu, Ning; Neswold, Richard; Carmichael, Linden

    2015-11-15

    The Machine Protection System (MPS) for the Fermilab Accelerator Science and Technology Facility (FAST) has been implemented and tested. The system receives signals from several subsystems and devices which conveys the relevant status needed to the safely operate the accelerator. Logic decisions are made based on these inputs and some predefined user settings which in turn controls the gate signal to the laser of the photo injector. The inputs of the system have a wide variety of signal types, encoding methods and urgencies for which the system is designed to accommodate. The MPS receives fast shutdown (FSD) signals generated by the beam loss system and inhibits the beam or reduces the beam intensity within a macropulse when the beam losses at several places along the accelerator beam line are higher than acceptable values. TTL or relay contact signals from the vacuum system, toroids, magnet systems etc., are chosen with polarities that ensure safe operation of the accelerator from unintended events such as cable disconnection in the harsh industrial environment of the experimental hall. A RS422 serial communication scheme is used to interface the operation permit generator module and a large number of movable devices each reporting multi-bit status. The system also supports operations at user defined lower beam levels for system conunissioning. The machine protection system is implemented with two commercially available off-the-shelf VMEbus based modules with on board FPGA devices. The system is monitored and controlled via the VMEbus by a single board CPU

  10. Artificial intelligence research in particle accelerator control systems for beam line tuning

    SciTech Connect

    Pieck, Martin

    2008-01-01

    Tuning particle accelerators is time consuming and expensive, with a number of inherently non-linear interactions between system components. Conventional control methods have not been successful in this domain and the result is constant and expensive monitoring of the systems by human operators. This is particularly true for the start-up and conditioning phase after a maintenance period or an unexpected fault. In turn, this often requires a step-by-step restart of the accelerator. Surprisingly few attempts have been made to apply intelligent accelerator control techniques to help with beam tuning, fault detection, and fault recovery problems. The reason for that might be that accelerator facilities are rare and difficult to understand systems that require detailed expert knowledge about the underlying physics as well as months if not years of experience to understand the relationship between individual components, particularly if they are geographically disjoint. This paper will give an overview about the research effort in the accelerator community that has been dedicated to the use of artificial intelligence methods for accelerator beam line tuning.

  11. The Datacon Master -- Renovation of a Datacon field bus communications system for accelerator control

    SciTech Connect

    Kerner, T.M.

    1995-05-01

    The Datacon system is a serial coaxial transformer isolated communication field bus system used to control and monitor accelerator remote devices. The Datacon field bus has been a BNL accelerator standard since its initial use in 1965. A single Datacon field bus supports up to 256 devices on a multidrop RG62A/U coaxial cable with up to 33 devices or 2,000 feet between repeaters or buffered branches. The forcing factor to renovate was the inability to repair the aging PDP-8E and PDP10 computers. The maintenance on this aging system was costly and the large number of accelerator devices dependent on the Datacon system could not be converted in a reasonable period of time to a new modern field bus. A commercial VMEbus host CPU mated with a custom designed VMEbus SBC event driven serial communications engine featuring a superscaler RISC 32-bit Intel i960 CPU met the design challenge. The commercial VMEbus host runs the VxWorks real-time operating system and connects to UNIX workstations over a Ethernet LAN. The V110 Datacon Master is the custom designed front end computer that integrates an accelerator event time line system with accelerator devices for up to 8 ppm users adding new capabilities.

  12. Concept, implementation and commissioning of the automation system for the accelerator module test facility AMTF

    SciTech Connect

    Böckmann, Torsten A.; Korth, Olaf; Clausen, Matthias; Schoeneburg, Bernd

    2014-01-29

    The European XFEL project launched on June 5, 2007 will require about 103 accelerator modules as a main part of the XFEL linear accelerator. All superconducting components constituting the accelerator module like cavities and magnets have to be tested before the assembly. For the tests of the individual cavities and the complete modules an XFEL Accelerator Module Test Facility (AMTF) has been erected at DESY. The process control system EPICS (Experimental Physics and Industrial Control System) is used to control and operate the cryogenic plant and all its subcomponents. A complementary component of EPICS is the Open Source software suit CSS (Control System Studio). CSS is an integrated engineering, maintenance and operating tool for EPICS. CSS enables local and remote operating and monitoring of the complete system and thus represents the human machine interface. More than 250 PROFIBUS nodes work at the accelerator module test facility. DESY installed an extensive diagnostic and condition monitoring system. With these diagnostic tools it is possible to examine the correct installation and configuration of all PROFIBUS nodes in real time. The condition monitoring system based on FDT/DTM technology shows the state of the PROFIBUS devices at a glance. This information can be used for preventive maintenance which is mandatory for continuous operation of the AMTF facility. The poster will describe all steps form engineering to implementation and commissioning.

  13. Quantized string models

    NASA Astrophysics Data System (ADS)

    Fradkin, E. S.; Tseytlin, A. A.

    1982-10-01

    We discuss and compare the Lorentz covariant path integral quantization of the three bose string models, namely, the Nambu, Eguchi and Brink-Di Vecchia-Howe-Polyakov (BDHP) ones. Along with a critical review of the subject with some uncertainties and ambiguities clearly stated, various new results are presented. We work out the form of the BDHP string ansatz for the Wilson average and prove a formal inequivalence of the exact Nambu and BDHP models for any space-time dimension d. The above three models, known to be equivalent on the classical level, are shown to be equivalent in a semiclassical approximation near a minimal surface and also in the leading 1/d- approximation for the static overlineqq-potential. We analyse scattering amplitudes predicted by the BDHP string and find that when exactly calculated for d < 26 they are different from the old dual ones, and possess a non-linear spectrum which may be considered as free from tachyons in the ground state.

  14. THE FLOW AROUND A COSMIC STRING. I. HYDRODYNAMIC SOLUTION

    SciTech Connect

    Beresnyak, Andrey

    2015-05-10

    Cosmic strings are linear topological defects which are hypothesized to be produced during inflation. Most searches for strings have relied on the string’s lensing of background galaxies or the cosmic microwave background. In this paper, I obtained a solution for the supersonic flow of collisional gas past the cosmic string which has two planar shocks with a shock compression ratio that depends on the angle defect of the string and its speed. The shocks result in the compression and heating of the gas and, given favorable conditions, particle acceleration. Gas heating and over-density in an unusual wedge shape can be detected by observing the Hi line at high redshifts. Particle acceleration can occur in the present-day universe when the string crosses the hot gas contained in galaxy clusters and, since the consequences of such a collision persist for cosmological timescales, could be located by looking at unusual large-scale radio sources situated on a single spatial plane.

  15. Simulator for an Accelerator-Driven Subcritical Fissile Solution System

    SciTech Connect

    Klein, Steven Karl; Day, Christy M.; Determan, John C.

    2015-09-14

    LANL has developed a process to generate a progressive family of system models for a fissile solution system. This family includes a dynamic system simulation comprised of coupled nonlinear differential equations describing the time evolution of the system. Neutron kinetics, radiolytic gas generation and transport, and core thermal hydraulics are included in the DSS. Extensions to explicit operation of cooling loops and radiolytic gas handling are embedded in these systems as is a stability model. The DSS may then be converted to an implementation in Visual Studio to provide a design team the ability to rapidly estimate system performance impacts from a variety of design decisions. This provides a method to assist in optimization of the system design. Once design has been generated in some detail the C++ version of the system model may then be implemented in a LabVIEW user interface to evaluate operator controls and instrumentation and operator recognition and response to off-normal events. Taken as a set of system models the DSS, Visual Studio, and LabVIEW progression provides a comprehensive set of design support tools.

  16. Coulomb string tension, asymptotic string tension, and the gluon chain

    DOE PAGES

    Greensite, Jeff; Szczepaniak, Adam P.

    2015-02-01

    We compute, via numerical simulations, the non-perturbative Coulomb potential and position-space ghost propagator in pure SU(3) gauge theory in Coulomb gauge. We find that that the Coulomb potential scales nicely in accordance with asymptotic freedom, that the Coulomb potential is linear in the infrared, and that the Coulomb string tension is about four times larger than the asymptotic string tension. We explain how it is possible that the asymptotic string tension can be lower than the Coulomb string tension by a factor of four.

  17. Effects of anisotropic dynamics on cosmic strings

    SciTech Connect

    Kunze, Kerstin E.

    2011-08-01

    The dynamics of cosmic strings is considered in anisotropic backgrounds. In particular, the behaviour of infinitely long straight cosmic strings and of cosmic string loops is determined. Small perturbations of a straight cosmic string are calculated. The relevance of these results is discussed with respect to the possible observational imprints of an anisotropic phase on the behaviour of a cosmic string network.

  18. Biocellion: accelerating computer simulation of multicellular biological system models

    PubMed Central

    Kang, Seunghwa; Kahan, Simon; McDermott, Jason; Flann, Nicholas; Shmulevich, Ilya

    2014-01-01

    Motivation: Biological system behaviors are often the outcome of complex interactions among a large number of cells and their biotic and abiotic environment. Computational biologists attempt to understand, predict and manipulate biological system behavior through mathematical modeling and computer simulation. Discrete agent-based modeling (in combination with high-resolution grids to model the extracellular environment) is a popular approach for building biological system models. However, the computational complexity of this approach forces computational biologists to resort to coarser resolution approaches to simulate large biological systems. High-performance parallel computers have the potential to address the computing challenge, but writing efficient software for parallel computers is difficult and time-consuming. Results: We have developed Biocellion, a high-performance software framework, to solve this computing challenge using parallel computers. To support a wide range of multicellular biological system models, Biocellion asks users to provide their model specifics by filling the function body of pre-defined model routines. Using Biocellion, modelers without parallel computing expertise can efficiently exploit parallel computers with less effort than writing sequential programs from scratch. We simulate cell sorting, microbial patterning and a bacterial system in soil aggregate as case studies. Availability and implementation: Biocellion runs on x86 compatible systems with the 64 bit Linux operating system and is freely available for academic use. Visit http://biocellion.com for additional information. Contact: seunghwa.kang@pnnl.gov PMID:25064572

  19. Factorization of chiral string amplitudes

    NASA Astrophysics Data System (ADS)

    Huang, Yu-tin; Siegel, Warren; Yuan, Ellis Ye

    2016-09-01

    We re-examine a closed-string model defined by altering the boundary conditions for one handedness of two-dimensional propagators in otherwise-standard string theory. We evaluate the amplitudes using Kawai-Lewellen-Tye factorization into open-string amplitudes. The only modification to standard string theory is effectively that the spacetime Minkowski metric changes overall sign in one open-string factor. This cancels all but a finite number of states: as found in earlier approaches, with enough supersymmetry (e.g., type II) the tree amplitudes reproduce those of the massless truncation of ordinary string theory. However, we now find for the other cases that additional fields, formerly thought to be auxiliary, describe new spin-2 states at the two adjacent mass levels (tachyonic and tardyonic). The tachyon is always a ghost, but can be avoided in the heterotic case.

  20. String fluid in local equilibrium

    NASA Astrophysics Data System (ADS)

    Schubring, Daniel; Vanchurin, Vitaly

    2014-10-01

    We study the solutions of string fluid equations under the assumption of a local equilibrium which was previously obtained in the context of the kinetic theory. We show that the fluid can be foliated into noninteracting submanifolds whose equations of motion are exactly that of the wiggly strings considered previously by Vilenkin and Carter. In a special case of negligible statistical variance in either the left- or the right-moving directions of microscopic strings, the submanifolds are described by the action of a null-current-carrying chiral string. When both variances vanish the submanifolds are described by the Nambu-Goto action and the string fluid reduces to the string dust introduced by Stachel.

  1. Stabilization of an axially moving accelerated/decelerated system via an adaptive boundary control.

    PubMed

    Liu, Yu; Zhao, Zhijia; He, Wei

    2016-09-01

    In this study, an adaptive boundary control is developed for vibration suppression of an axially moving accelerated/decelerated belt system. The dynamic model of the belt system is represented by partial-ordinary differential equations with consideration of the high acceleration/deceleration and unknown distributed disturbance. By utilizing adaptive technique and Lyapunov-based back stepping method, an adaptive boundary control is proposed for vibration suppression of the belt system, a disturbance observer is introduced to attenuate the effects of unknown boundary disturbance, the adaptive law is developed to handle parametric uncertainties and the S-curve acceleration/deceleration method is adopted to plan the belt׳s speed. With the proposed control scheme, the well-posedness and stability of the closed-loop system are mathematically demonstrated. Simulations are displayed to illustrate the effectiveness of the proposed control. PMID:27269191

  2. Three dimensional finite element methods: Their role in the design of DC accelerator systems

    SciTech Connect

    Podaru, Nicolae C.; Gottdang, A.; Mous, D. J. W.

    2013-04-19

    High Voltage Engineering has designed, built and tested a 2 MV dual irradiation system that will be applied for radiation damage studies and ion beam material modification. The system consists of two independent accelerators which support simultaneous proton and electron irradiation (energy range 100 keV - 2 MeV) of target sizes of up to 300 Multiplication-Sign 300 mm{sup 2}. Three dimensional finite element methods were used in the design of various parts of the system. The electrostatic solver was used to quantify essential parameters of the solid-state power supply generating the DC high voltage. The magnetostatic solver and ray tracing were used to optimize the electron/ion beam transport. Close agreement between design and measurements of the accelerator characteristics as well as beam performance indicate the usefulness of three dimensional finite element methods during accelerator system design.

  3. System for producing high-resolution polarized and unpolarized beams with a tandem accelerator

    SciTech Connect

    Westerfeldt, C.R.; Bilpuch, E.G.; Bleck, M.E.; Outlaw, D.A.; Wells, W.K.; Wilkerson, J.F.; Clegg, T.B.

    1983-01-01

    A tandem accelerator beam energy stabilizer, which utilizes an optically coupled fast feedback loop to the accelerator terminal stripper, is described. Emphasis is placed on the components of the feedback system and on the application of this system to production of high energy-resolution beams. This system produces beam energy spreads ranging from 450 to 600 eV FWHM for 2 to 16 MeV unpolarized protons. Polarized beam energy spreads range from 550 to 700 eV FWHM, for the same beam energy range.

  4. Phase and amplitude control system for Stanford Linear Accelerator

    SciTech Connect

    Yoo, S.J.

    1983-09-26

    The computer controlled phase and amplitude detection system measures the instantaneous phase and amplitude of a 1 micro-second 2856 MHz rf pulse at a 180 Hz rate. This will be used for phase feedback control, and also for phase and amplitude jitter measurement. The program, which was originally written by John Fox and Keith Jobe, has been modified to improve the function of the system. The software algorithms used in the measurement are described, as is the performance of the prototype phase and amplitude detector system.

  5. The electron-optical system of the LIU-2 induction accelerator

    NASA Astrophysics Data System (ADS)

    Kuznetsov, G. I.; Batazova, M. A.

    2014-09-01

    The electron-optical system (EOS) of an induction accelerator for generation of an electron beam with an energy of 2 MeV, a current of 2 kA, an impulse duration of 2 × 10-7 s, and a geometric output emittance not exceeding the thermal value of it is described. The EOS consists of two parts. The first part is a diode gun with a perveance of 2 × 10-6 A/B3/2 and a cathode-anode voltage of 1 MeV. The second part is an accelerating tube with uniform distribution of the same accelerating voltage. A beam is transported at a distance of about 4 m from the cathode and focused on a spot with a diameter of about 1 mm. The compliance tests results of the linear-induction accelerator precisely conform to the calculated design parameters.

  6. Experimenting with string musical instruments

    NASA Astrophysics Data System (ADS)

    LoPresto, Michael C.

    2012-03-01

    What follows are several investigations involving string musical instruments developed for and used in a Science of Sound & Light course. The experiments make use of a guitar, orchestral string instruments and data collection and graphing software. They are designed to provide students with concrete examples of how mathematical formulae, when used in physics, represent reality that can actually be observed, in this case, the operation of string musical instruments.

  7. Classical theory of radiating strings

    NASA Technical Reports Server (NTRS)

    Copeland, Edmund J.; Haws, D.; Hindmarsh, M.

    1990-01-01

    The divergent part of the self force of a radiating string coupled to gravity, an antisymmetric tensor and a dilaton in four dimensions are calculated to first order in classical perturbation theory. While this divergence can be absorbed into a renormalization of the string tension, demanding that both it and the divergence in the energy momentum tensor vanish forces the string to have the couplings of compactified N = 1 D = 10 supergravity. In effect, supersymmetry cures the classical infinities.

  8. Cosmic string induced CMB maps

    SciTech Connect

    Landriau, M.; Shellard, E. P. S.

    2011-02-15

    We compute maps of CMB temperature fluctuations seeded by cosmic strings using high resolution simulations of cosmic strings in a Friedmann-Robertson-Walker universe. We create full-sky, 18 deg. and 3 deg. CMB maps, including the relevant string contribution at each resolution from before recombination to today. We extract the angular power spectrum from these maps, demonstrating the importance of recombination effects. We briefly discuss the probability density function of the pixel temperatures, their skewness, and kurtosis.

  9. Non-supersymmetric string theory

    NASA Astrophysics Data System (ADS)

    Martinec, Emil J.; Robbins, Daniel; Sethi, Savdeep

    2011-10-01

    A class of non-supersymmetric string backgrounds can be constructed using twists that involve space-time fermion parity. We propose a non-perturbative definition of string theory in these backgrounds via gauge theories with supersymmetry softly broken by twisted boundary conditions. The perturbative string spectrum is reproduced, and qualitative effects of the interactions are discussed. Along the way, we find an interesting mechanism for inflation. The end state of closed string tachyon condensation is a highly excited state in the gauge theory which, in all likelihood, does not have a geometric interpretation.

  10. Evolution of cosmic string networks

    NASA Technical Reports Server (NTRS)

    Albrecht, Andreas; Turok, Neil

    1989-01-01

    Results on cosmic strings are summarized including: (1) the application of non-equilibrium statistical mechanics to cosmic string evolution; (2) a simple one scale model for the long strings which has a great deal of predictive power; (3) results from large scale numerical simulations; and (4) a discussion of the observational consequences of our results. An upper bound on G mu of approximately 10(-7) emerges from the millisecond pulsar gravity wave bound. How numerical uncertainties affect this are discussed. Any changes which weaken the bound would probably also give the long strings the dominant role in producing observational consequences.

  11. Evolution of cosmic string networks

    SciTech Connect

    Albrecht, A.; Turok, N.

    1989-06-01

    We summarize our new results on cosmic strings. These results include: the application of non-equilibrium statistical mechanics to cosmic string evolution, a simple ''one scale'' model for the long strings which has a great deal of predictive power, results from large scale numerical simulations, and a discussion of the observational consequences of our results. An upper bond on G/mu/ of approximately 10/sup /minus/7/ emerges from the millisecond pulsar gravity wave bound. We discuss how numerical uncertainties affect this. Any changes which weaken the bound would probably also give the long strings the dominant role in producing observational consequences. 22 refs.

  12. Cosmic sparks from superconducting strings.

    PubMed

    Vachaspati, Tanmay

    2008-10-01

    We investigate cosmic sparks from cusps on superconducting cosmic strings in light of the recently discovered millisecond radio burst by Lorimer et al.. We find that the observed duration, fluence, spectrum, and event rate can be reasonably explained by grand unification scale superconducting cosmic strings that carry currents approximately 10{5} GeV. The superconducting string model predicts an event rate that falls off only as S{-1/2}, where S is the energy flux, and hence predicts a population of very bright bursts. Other surveys, with different observational parameters, are shown to impose tight constraints on the superconducting string model. PMID:18851517

  13. Cosmic Sparks from Superconducting Strings

    SciTech Connect

    Vachaspati, Tanmay

    2008-10-03

    We investigate cosmic sparks from cusps on superconducting cosmic strings in light of the recently discovered millisecond radio burst by Lorimer et al.. We find that the observed duration, fluence, spectrum, and event rate can be reasonably explained by grand unification scale superconducting cosmic strings that carry currents {approx}10{sup 5} GeV. The superconducting string model predicts an event rate that falls off only as S{sup -1/2}, where S is the energy flux, and hence predicts a population of very bright bursts. Other surveys, with different observational parameters, are shown to impose tight constraints on the superconducting string model.

  14. New class of accelerating black hole solutions

    SciTech Connect

    Camps, Joan; Emparan, Roberto

    2010-07-15

    We construct several new families of vacuum solutions that describe black holes in uniformly accelerated motion. They generalize the C metric to the case where the energy density and tension of the strings that pull (or push) on the black holes are independent parameters. These strings create large curvatures near their axis and when they have infinite length they modify the asymptotic properties of the spacetime, but we discuss how these features can be dealt with physically, in particular, in terms of 'wiggly cosmic strings'. We comment on possible extensions and extract lessons for the problem of finding higher-dimensional accelerating black hole solutions.

  15. 10-GW CO{sub 2} laser system at the Brookhaven Accelerator Test Facility

    SciTech Connect

    Pogorelsky, I.; Fischer, J.; Fisher, A.S.

    1993-12-31

    Design and performance of a high peak-power CO{sub 2} laser system to produce subnanosecond IR pulses for electron acceleration experiment are presented. We discuss theoretical aspects of the picosecond laser pulse propagation in a molecular amplifier and a design approach towards compact Terawatt CO{sub 2} laser systems.

  16. A beamline systems model for Accelerator-Driven Transmutation Technology (ADTT) facilities

    NASA Astrophysics Data System (ADS)

    Todd, Alan M. M.; Paulson, C. C.; Peacock, M. A.; Reusch, M. F.

    1995-09-01

    A beamline systems code, that is being developed for Accelerator-Driven Transmutation Technology (ADTT) facility trade studies, is described. The overall program is a joint Grumman, G. H. Gillespie Associates (GHGA) and Los Alamos National Laboratory effort. The GHGA Accelerator Systems Model (ASM) has been adopted as the framework on which this effort is based. Relevant accelerator and beam transport models from earlier Grumman systems codes are being adapted to this framework. Preliminary physics and engineering models for each ADTT beamline component have been constructed. Examples noted include a Bridge Coupled Drift Tube Linac (BCDTL) and the accelerator thermal system. A decision has been made to confine the ASM framework principally to beamline modeling, while detailed target/blanket, balance-of-plant and facility costing analysis will be performed externally. An interfacing external balance-of-plant and facility costing model, which will permit the performance of iterative facility trade studies, is under separate development. An ABC (Accelerator Based Conversion) example is used to highlight the present models and capabilities.

  17. A beamline systems model for Accelerator-Driven Transmutation Technology (ADTT) facilities

    SciTech Connect

    Todd, Alan M. M.; Paulson, C. C.; Peacock, M. A.; Reusch, M. F.

    1995-09-15

    A beamline systems code, that is being developed for Accelerator-Driven Transmutation Technology (ADTT) facility trade studies, is described. The overall program is a joint Grumman, G. H. Gillespie Associates (GHGA) and Los Alamos National Laboratory effort. The GHGA Accelerator Systems Model (ASM) has been adopted as the framework on which this effort is based. Relevant accelerator and beam transport models from earlier Grumman systems codes are being adapted to this framework. Preliminary physics and engineering models for each ADTT beamline component have been constructed. Examples noted include a Bridge Coupled Drift Tube Linac (BCDTL) and the accelerator thermal system. A decision has been made to confine the ASM framework principally to beamline modeling, while detailed target/blanket, balance-of-plant and facility costing analysis will be performed externally. An interfacing external balance-of-plant and facility costing model, which will permit the performance of iterative facility trade studies, is under separate development. An ABC (Accelerator Based Conversion) example is used to highlight the present models and capabilities.

  18. Modeling of accelerator systems and experimental verification of Quarter-Wave Resonator steering

    NASA Astrophysics Data System (ADS)

    Benatti, Carla

    Increasingly complicated accelerator systems depend more and more on computing power and computer simulations for their operation as progress in the field has led to cutting-edge advances that require finer control and better understanding to achieve optimal performance. Greater ambitions coupled with the technical complexity of today's state-of-the-art accelerators necessitate corresponding advances in available accelerator modeling resources. Modeling is a critical component of any field of physics, accelerator physics being no exception. It is extremely important to not only understand the basic underlying physics principles but to implement this understanding through the development of relevant modeling tools that provide the ability to investigate and study various complex effects. Moreover, these tools can lead to new insight and applications that facilitate control room operations and enable advances in the field that would not otherwise be possible. The ability to accurately model accelerator systems aids in the successful operation of machines designed specifically to deliver beams to experiments across a wide variety of fields, ranging from material science research to nuclear astrophysics. One such accelerator discussed throughout this work is the ReA facility at the National Superconducting Cyclotron Laboratory (NSCL) which re-accelerates rare isotope beams for nuclear astrophysics experiments. A major component of the ReA facility, as well as the future Facility for Rare Isotope Beams (FRIB) among other accelerators, is the Quarter-Wave Resonator (QWR), a coaxial accelerating cavity convenient for efficient acceleration of low-velocity particles. This device is very important to model accurately as it operates in the critical low-velocity region where the beam's acceleration gains are proportionally larger than they are through the later stages of acceleration. Compounding this matter, QWRs defocus the beam, and are also asymmetric with respect to the

  19. On designing a control system for a new generation of accelerators

    SciTech Connect

    Schaller, S.C.; Schultz, D.E.

    1987-01-01

    A well-conceived plan of attack is essential to the task of designing a control system for a large accelerator. Several aspects of such a plan have been investigated during recent work at LAMPF on design strategies for an Advanced Hadron Facility control system. Aspects discussed in this paper include: identification of requirements, creation and enforcement of standards, interaction with users, consideration of commercial controls products, integration with existing control systems, planning for continual change, and establishment of design reviews. We emphasize the need for the controls group to acquire and integrate accelerator design information from the start of the design process. We suggest that a controls design for a new generation of accelerators be done with a new generation of software tools. 12 refs.

  20. Cryogenic molecular separation system for radioactive 11C ion acceleration

    NASA Astrophysics Data System (ADS)

    Katagiri, K.; Noda, A.; Suzuki, K.; Nagatsu, K.; Boytsov, A. Yu.; Donets, D. E.; Donets, E. D.; Donets, E. E.; Ramzdorf, A. Yu.; Nakao, M.; Hojo, S.; Wakui, T.; Noda, K.

    2015-12-01

    A 11C molecular production/separation system (CMPS) has been developed as part of an isotope separation on line system for simultaneous positron emission tomography imaging and heavy-ion cancer therapy using radioactive 11C ion beams. In the ISOL system, 11CH4 molecules will be produced by proton irradiation and separated from residual air impurities and impurities produced during the irradiation. The CMPS includes two cryogenic traps to separate specific molecules selectively from impurities by using vapor pressure differences among the molecular species. To investigate the fundamental performance of the CMPS, we performed separation experiments with non-radioactive 12CH4 gases, which can simulate the chemical characteristics of 11CH4 gases. We investigated the separation of CH4 molecules from impurities, which will be present as residual gases and are expected to be difficult to separate because the vapor pressure of air molecules is close to that of CH4. We determined the collection/separation efficiencies of the CMPS for various amounts of air impurities and found desirable operating conditions for the CMPS to be used as a molecular separation device in our ISOL system.

  1. Validation of a prognostic multi-gene signature in high-risk neuroblastoma using the high throughput digital NanoString nCounter™ system.

    PubMed

    Stricker, Thomas P; Morales La Madrid, Andres; Chlenski, Alexandre; Guerrero, Lisa; Salwen, Helen R; Gosiengfiao, Yasmin; Perlman, Elizabeth J; Furman, Wayne; Bahrami, Armita; Shohet, Jason M; Zage, Peter E; Hicks, M John; Shimada, Hiroyuki; Suganuma, Rie; Park, Julie R; So, Sara; London, Wendy B; Pytel, Peter; Maclean, Kirsteen H; Cohn, Susan L

    2014-05-01

    Microarray-based molecular signatures have not been widely integrated into neuroblastoma diagnostic classification systems due to the complexities of the assay and requirement for high-quality RNA. New digital technologies that accurately quantify gene expression using RNA isolated from formalin-fixed paraffin embedded (FFPE) tissues are now available. In this study, we describe the first use of a high-throughput digital system to assay the expression of genes in an "ultra-high risk" microarray classifier in FFPE high-risk neuroblastoma tumors. Customized probes corresponding to the 42 genes in a published multi-gene neuroblastoma signature were hybridized to RNA isolated from 107 FFPE high-risk neuroblastoma samples using the NanoString nCounter™ Analysis System. For classification of each patient, the Pearson's correlation coefficient was calculated between the standardized nCounter™ data and the molecular signature from the microarray data. We demonstrate that the nCounter™ 42-gene panel sub-stratified the high-risk cohort into two subsets with statistically significantly different overall survival (p = 0.0027) and event-free survival (p = 0.028). In contrast, none of the established prognostic risk markers (age, stage, tumor histology, MYCN status, and ploidy) were significantly associated with survival. We conclude that the nCounter™ System can reproducibly quantify expression levels of signature genes in FFPE tumor samples. Validation of this microarray signature in our high-risk patient cohort using a completely different technology emphasizes the prognostic relevance of this classifier. Prospective studies testing the prognostic value of molecular signatures in high-risk neuroblastoma patients using FFPE tumor samples and the nCounter™ System are warranted.

  2. Validation of a Prognostic Multi-gene Signature in High-risk Neuroblastoma using the High Throughput Digital NanoString nCounter™ System

    PubMed Central

    Stricker, Thomas P.; La Madrid, Andres Morales; Chlenski, Alexandre; Guerrero, Lisa; Salwen, Helen R.; Gosiengfiao, Yasmin; Perlman, Elizabeth J.; Furman, Wayne; Bahrami, Armita; Shohet, Jason M.; Zage, Peter E.; Hicks, M. John; Shimada, Hiroyuki; Suganuma, Rie; Park, Julie R.; So, Sara; London, Wendy B.; Pytel, Peter; Maclean, Kirsteen H.; Cohn, Susan L.

    2014-01-01

    Microarray-based molecular signatures have not been widely integrated into neuroblastoma diagnostic classification systems due to the complexities of the assay and requirement for high-quality RNA. New digital technologies that accurately quantify gene expression using RNA isolated from formalin-fixed paraffin embedded (FFPE) tissues are now available. In this study, we describe the first use of a high-throughput digital system to assay the expression of genes in an “ultra-high risk” microarray classifier in FFPE high-risk neuroblastoma tumors. Customized probes corresponding to the 42 genes in a published multi-gene neuroblastoma signature were hybridized to RNA isolated from 107 FFPE high-risk neuroblastoma samples using the NanoString nCounter™ Analysis System. For classification of each patient, the Pearson’s correlation coefficient was calculated between the standardized nCounter™ data and the molecular signature from the microarray data. We demonstrate that the nCounter™ 42-gene panel sub-stratified the high-risk cohort into two subsets with statistically significantly different overall survival (p=0.0027) and event-free survival (p=0.028). In contrast, none of the established prognostic risk markers (age, stage, tumor histology, MYCN status, and ploidy) were significantly associated with survival. We conclude that the nCounter™ System can reproducibly quantify expression levels of signature genes in FFPE tumor samples. Validation of this microarray signature in our high-risk patient cohort using a completely different technology emphasizes the prognostic relevance of this classifier. Prospective studies testing the prognostic value of molecular signatures in high-risk neuroblastoma patients using FFPE tumor samples and the nCounter™ System are warranted. PMID:24560446

  3. 1. PLENUM WALL, SHOWING BALL AND STRING DAMPER CONTROLS. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. PLENUM WALL, SHOWING BALL AND STRING DAMPER CONTROLS. - Hot Springs National Park, Bathhouse Row, Lamar Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

  4. Transfer of Strings to the Module Fixture

    NASA Technical Reports Server (NTRS)

    Frasch, W.

    1982-01-01

    Work station for transferring entire strings of solar cells places successive strings alined, with offset, or reversed end for end. Thus, various solar module formats can be accommodated. Two vacuum cups hold each solar cell in string being transferred.

  5. Reliability and availability considerations in the RF systems of ATW-class accelerators

    NASA Astrophysics Data System (ADS)

    Tallerico, Paul J.; Lynch, Michael T.; Lawrence, George

    1995-09-01

    In an RF-driven, ion accelerator for waste transmutation or nuclear material production, the overall availability is perhaps the most important specification. The synchronism requirements in an ion accelerator, as contrasted to an electron accelerator, cause a failure of an RF source to have a greater consequence. These large machines also are major capital investments, so the availability determines the return on this capital. RF system design methods to insure a high availability without paying a serious cost penalty are the subject of this paper. The overall availability goal in our present designs is 75% for the entire ATW complex, and from 25 to 35% of the unavailability is allocated to the RF system, since it is one of the most complicated subsystems in the complex. The allowed down time for the RF system (including the linac and all other subsystems) is then only 7 to 9% of the operating time per year, or as little as 613 hours per year, for continuous operation. Since large accelerators consume large amounts of electrical power, excellent efficiency is also required with the excellent availability. The availability also influences the sizes of the RF components: smaller components may fail and yet the accelerator may still meet all specifications. Larger components are also attractive, since the cost of an RF system usually increases as the square root of the number of RF systems utilized. In some cases, there is a reliability penalty that accompanies the cost savings from using larger components. We discuss these factors, and present an availability model that allows one to examine these trade offs, and make rational choices in the RF and accelerator system designs.

  6. String creation, D-branes and effective field theory

    NASA Astrophysics Data System (ADS)

    Hung, Ling-Yan

    2008-04-01

    This paper addresses several unsettled issues associated with string creation in systems of orthogonal Dp-D(8-p) branes. The interaction between the branes can be understood either from the closed string or open string picture. In the closed string picture it has been noted that the DBI action fails to capture an extra RR exchange between the branes. We demonstrate how this problem persists upon lifting to M-theory. These D-brane systems are analysed in the closed string picture by using gauge-fixed boundary states in a non-standard lightcone gauge, in which RR exchange can be analysed precisely. The missing piece in the DBI action also manifests itself in the open string picture as a mismatch between the Coleman-Weinberg potential obtained from the effective field theory and the corresponding open string calculation. We show that this difference can be reconciled by taking into account the superghosts in the (0+1) effective theory of the chiral fermion, that arises from gauge fixing the spontaneously broken world-line local supersymmetries.

  7. M-strings, monopole strings, and modular forms

    NASA Astrophysics Data System (ADS)

    Hohenegger, Stefan; Iqbal, Amer; Rey, Soo-Jong

    2015-09-01

    We study relations between M-strings (one-dimensional intersections of M2-branes and M5-branes) in six dimensions and m-strings (magnetically charged monopole strings) in five dimensions. For specific configurations, we propose that the counting functions of Bogomol'nyi-Prasad-Sommerfield (BPS) bound states of M-strings capture the elliptic genus of the moduli space of m-strings. We check this proposal for the known cases, the Taub-NUT and Atiyah-Hitchin spaces, for which we find complete agreement. We further analyze the modular properties of the M-string free energies and find that they do not transform covariantly under S L (2 ,Z ). However, for a given number of M-strings, we show that there exists a unique combination of unrefined genus-zero free energies that transforms as a Jacobi form under a congruence subgroup of S L (2 ,Z ). These combinations correspond to summing over different numbers of M5-branes and make sense only if the distances between them are all equal. We explain that this is a necessary condition for the m-string moduli space to be factorizable into relative and center-of-mass parts.

  8. Accelerating Acceptance of Fuel Cell Backup Power Systems - Final Report

    SciTech Connect

    Petrecky, James; Ashley, Christopher

    2014-07-21

    Since 2001, Plug Power has installed more than 800 stationary fuel cell systems worldwide. Plug Power’s prime power systems have produced approximately 6.5 million kilowatt hours of electricity and have accumulated more than 2.5 million operating hours. Intermittent, or backup, power products have been deployed with telecommunications carriers and government and utility customers in North and South America, Europe, the United Kingdom, Japan and South Africa. Some of the largest material handling operations in North America are currently using the company’s motive power units in fuel cell-powered forklifts for their warehouses, distribution centers and manufacturing facilities. The low-temperature GenSys fuel cell system provides remote, off-grid and primary power where grid power is unreliable or nonexistent. Built reliable and designed rugged, low- temperature GenSys delivers continuous or backup power through even the most extreme conditions. Coupled with high-efficiency ratings, low-temperature GenSys reduces operating costs making it an economical solution for prime power requirements. Currently, field trials at telecommunication and industrial sites across the globe are proving the advantages of fuel cells—lower maintenance, fuel costs and emissions, as well as longer life—compared with traditional internal combustion engines.

  9. Optimizing a mobile robot control system using GPU acceleration

    NASA Astrophysics Data System (ADS)

    Tuck, Nat; McGuinness, Michael; Martin, Fred

    2012-01-01

    This paper describes our attempt to optimize a robot control program for the Intelligent Ground Vehicle Competition (IGVC) by running computationally intensive portions of the system on a commodity graphics processing unit (GPU). The IGVC Autonomous Challenge requires a control program that performs a number of different computationally intensive tasks ranging from computer vision to path planning. For the 2011 competition our Robot Operating System (ROS) based control system would not run comfortably on the multicore CPU on our custom robot platform. The process of profiling the ROS control program and selecting appropriate modules for porting to run on a GPU is described. A GPU-targeting compiler, Bacon, is used to speed up development and help optimize the ported modules. The impact of the ported modules on overall performance is discussed. We conclude that GPU optimization can free a significant amount of CPU resources with minimal effort for expensive user-written code, but that replacing heavily-optimized library functions is more difficult, and a much less efficient use of time.

  10. Short communication: a system for remote monitoring of a hospital linear accelerator.

    PubMed

    Jennings, C S

    1996-05-01

    Linear accelerators are complex machines with many parameters affecting the quality of the treatment beam delivered. A high level of technical support is required but this can be difficult to achieve if the linear accelerator is at a centre distant from a medical physics department. This paper describes a solution to this problem whereby a newly installed linear accelerator at the Royal Shrewsbury Hospital is remotely monitored from the Royal Hospital, Wolverhampton. The system enables run-up procedures to be completed by guiding radiographers at Shrewsbury through a series of steps. It consists of electronic hardware connected to the linear accelerator, under the control of a computer. The machine parameters are read and tested against preset tolerances. The monitoring system has been installed and is in routine use. The benefits have been shown to be: a saving in staff time and travel costs, the satisfactory completion of run-up procedures, a higher level of efficiency in the medical physics service provided and effective quality control. Finally, some future developments are presented. These include the development of a real time remote monitoring system that constantly monitors the linear accelerator, allowing the Medical Physics Department access to the machine parameters at any time.

  11. Sequestering in String Theory

    SciTech Connect

    Kachru, Shamit; McAllister, Liam; Sundrum, Raman

    2007-04-04

    We study sequestering, a prerequisite for flavor-blind supersymmetry breaking in several high-scale mediation mechanisms, in compactifications of type IIB string theory. We find that although sequestering is typically absent in unwarped backgrounds, strongly warped compactifications do readily sequester. The AdS/CFT dual description in terms of conformal sequestering plays an important role in our analysis, and we establish how sequestering works both on the gravity side and on the gauge theory side. We pay special attention to subtle compactification effects that can disrupt sequestering. Our result is a step toward realizing an appealing pattern of soft terms in a KKLT compactification.

  12. Beam Test of Multi-Bunch Energy Compensation System in the Accelerator Test Facility at KEK

    NASA Astrophysics Data System (ADS)

    Kashiwagi, Shigeru; Hayano, Hitoshi; Kubo, Kiyoshi; Korhonen, Timo; Nakamura, Shogo; Naito, Takashi; Oide, Katsunobu; Takeda, Seishi; Terunuma, Nobuhiro; Urakawa, Junji

    2004-08-01

    A beam test of the multi-bunch energy compensation system (ECS) was performed using the Δ F method with the 2856± 4.327 MHz accelerating structures in the accelerator test facility (ATF) at KEK. The 1.54 GeV S-band linac of the ATF was designed to accelerate a multi-bunch beam that consists of 20 bunches with 2.8 ns spacing. The multi-bunch beam with 2.0× 1010 electrons/bunch has an energy deviation of about 8.5% at the end of the linac due to transient beam loading without ECS. The ATF linac is the injector of the ATF damping ring (DR), whose energy acceptance is ± 0.5%. The beam loading compensation system is necessary in the ATF linac for the successful injection of multi-bunch into DR. The rf system of the linac consists of 8 regular rf units with the SLED system and 2 ECS rf units without the SLED system. The accelerating structures of the regular units are driven at 2856 MHz and the 2 ECS structures are operated with slightly different rf frequencies of 2856± 4.327 MHz. In the beam test, we have succeeded in compressing the multi-bunch energy spread within the energy acceptance of the DR using Δ F ECS. The principle of the beam loading compensation system of KEK-ATF and the experimental results are described in this paper.

  13. String networks in ZN Lotka-Volterra competition models

    NASA Astrophysics Data System (ADS)

    Avelino, P. P.; Bazeia, D.; Menezes, J.; de Oliveira, B. F.

    2014-01-01

    In this Letter we give specific examples of ZN Lotka-Volterra competition models leading to the formation of string networks. We show that, in order to promote coexistence, the species may arrange themselves around regions with a high number density of empty sites generated by predator-prey interactions between competing species. These configurations extend into the third dimension giving rise to string networks. We investigate the corresponding dynamics using both stochastic and mean field theory simulations, showing that the coarsening of these string networks follows a scaling law which is analogous to that found in other physical systems in condensed matter and cosmology.

  14. Development of an RF Conditioning System for Charged-Particle Accelerators

    SciTech Connect

    Kang, Yoon W; Howlader, Mostofa; Shajedul Hasan, Dr. S. M.

    2008-01-01

    Charged-particle accelerators use various vacuum windows on their accelerating radio-frequency (RF) cavities to throughput very high RF power. Before being placed on the cavities, the windows should be cleaned, baked, and fully RF conditioned to prevent a poor vacuum from outgassing, as well as other forms of contamination. An example is the coaxial fundamental power coupler (FPC) with an annular alumina ceramic window for each of the 81 superconducting RF cavities in the Spallation Neutron Source (SNS) linear accelerator. The FPCs needed to be tested up to 650-kW peak in a traveling wave and 2.6 MW with standing wave peaks in 1.3 and 60 pulses/s at 805 MHz. In this paper, an Experimental-Physics-and-Industrial-Control-System-based RF conditioning system for the SNS RF test facility is presented. This paper summarizes the hardware and software design strategies, provides the results obtained, and describes the future research scope.

  15. System identification of mechanomyograms detected with an acceleration sensor and a laser displacement meter.

    PubMed

    Uchiyama, Takanori; Shinohara, Keita

    2011-01-01

    The purpose of this study is to investigate the transfer functions of mechanomyograms (MMGs) detected with an acceleration sensor and a laser displacement meter. The MMGs evoked by electrical stimulation to the peroneal nerve were recorded on the skin of the tibial anterior muscle. The displacement MMG (DMMG) and the acceleration MMG (AMMG) systems were identified using a singular value decomposition method. The appropriate order of the AMMG system was six and that of the DMMG system was four. The undamped natural frequencies of the systems were compared to resonance frequencies of human soft tissue. Some of the undamped natural frequencies estimated from the AMMG systems agreed with the resonance frequencies in the literature but others were lower than the resonance frequencies. The undamped natural frequencies estimated from the DMMG systems were lower than the resonance frequencies.

  16. A fiber optic strain measurement and quench localization system for use in superconducting accelerator dipole magnets

    SciTech Connect

    van Oort, J.M.; Scanlan, R.M.; ten Kate, H.H.J.

    1994-10-17

    A novel fiber-optic measurement system for superconducting accelerator magnets is described. The principal component is an extrinsic Fabry-Perot Interferometer to determine localized strain and stress in coil windings. The system can be used either as a sensitive relative strain measurement system or as an absolute strain detector. Combined, one can monitor the mechanical behaviour of the magnet system over time during construction, long time storage and operation. The sensing mechanism is described, together with various tests in laboratory environments. The test results of a multichannel test matrix to be incorporated first in the dummy coils and then in the final version of a 13T Nb{sub 3}Sn accelerator dipole magnet are presented. Finally, the possible use of this system as a quench localization system is proposed.

  17. Energy in a String Wave

    ERIC Educational Resources Information Center

    Ng, Chiu-king

    2010-01-01

    When one end of a taut horizontal elastic string is shaken repeatedly up and down, a transverse wave (assume sine waveform) will be produced and travel along it. College students know this type of wave motion well. They know when the wave passes by, each element of the string will perform an oscillating up-down motion, which in mechanics is termed…

  18. ISL - A String Manipulating Language.

    ERIC Educational Resources Information Center

    Kelley, K.C.; And Others.

    The Information Search Language (ISL), described in this report, is a problem-oriented language designed to facilitate the manipulation of real character strings with the Control Data 1604 computer. The report gives instructions for the language; these may be classified as Pseudo-ops, Word-Oriented instructions, Character-string instructions,…

  19. A Platonic Sextet for Strings

    ERIC Educational Resources Information Center

    Schaffer, Karl

    2012-01-01

    The use of traditional string figures by the Dr. Schaffer and Mr. Stern Dance Ensemble led to experimentation with polyhedral string constructions. This article presents a series of polyhedra made with six loops of three colors which sequence through all the Platonic Solids.

  20. Experimenting with String Musical Instruments

    ERIC Educational Resources Information Center

    LoPresto, Michael C.

    2012-01-01

    What follows are several investigations involving string musical instruments developed for and used in a "Science of Sound & Light" course. The experiments make use of a guitar, orchestral string instruments and data collection and graphing software. They are designed to provide students with concrete examples of how mathematical formulae, when…

  1. Improving cosmic string network simulations

    NASA Astrophysics Data System (ADS)

    Hindmarsh, Mark; Rummukainen, Kari; Tenkanen, Tuomas V. I.; Weir, David J.

    2014-08-01

    In real-time lattice simulations of cosmic strings in the Abelian Higgs model, the broken translational invariance introduces lattice artifacts; relativistic strings therefore decelerate and radiate. We introduce two different methods to construct a moving string on the lattice, and study in detail the lattice effects on moving strings. We find that there are two types of lattice artifact: there is an effective maximum speed with which a moving string can be placed on the lattice, and a moving string also slows down, with the deceleration approximately proportional to the exponential of the velocity. To mitigate this, we introduce and study an improved discretization, based on the tree-level Lüscher-Weisz action, which is found to reduce the deceleration by an order of magnitude, and to increase the string speed limit by an amount equivalent to halving the lattice spacing. The improved algorithm is expected to be very useful for 3D simulations of cosmic strings in the early Universe, where one wishes to simulate as large a volume as possible.

  2. French String Grammar. Final Report.

    ERIC Educational Resources Information Center

    New York Univ., NY. Linguistic String Project.

    This work reports on an initial study of the possibility of providing a suitable framework for the teaching of a foreign language grammar through string analysis, using French as the target language. Analysis of a string word list (word-class sequences) yields an overall view of the grammar. Details are furnished in a set of restrictions which…

  3. Solar-Cell String Conveyor

    NASA Technical Reports Server (NTRS)

    Frasch, W.; Ciavola, S.

    1982-01-01

    String-conveyor portion of solar-array assembly line holds silicon solar cells while assembled into strings and tested. Cells are transported collector-side-down, while uniform cell spacing and registration are maintained. Microprocessor on machine controls indexing of cells.

  4. Flat wormholes from cosmic strings.

    NASA Astrophysics Data System (ADS)

    Clement, G.

    1997-11-01

    The author describes the analytical extension of certain cylindrical multi-cosmic string metrics to wormhole spacetimes with only one region at spatial infinity, and investigates in detail the geometry of asymptotically Minkowskian wormhole spacetimes generated by one or two cosmic strings. It is found that such wormholes tend to lengthen rather than shorten space travel. Possible signatures of these wormholes are briefly discussed.

  5. Vacuum system of the 3MeV industrial electron beam accelerator

    NASA Astrophysics Data System (ADS)

    Jayaprakash, D.; Mishra, R. L.; Ghodke, S. R.; kumar, M.; kumar, M.; Nanu, K.; Mittal, K. C., Dr

    2008-05-01

    One DC Accelerator, for electron beam of 3 MeV energy and 10 mA beam current, to derive 30 KW beam power for Industrial applications is nearing completion at Electron Beam Centre, Kharghar, Navi Mumbai. Beam-line of the accelerator is six meters long, consists of electron gun at top, followed by the accelerating column and finally the scan horn. Electron gun and the accelerating column is exposed to SF6 gas at six atmospheres. Area exposed to the vacuum is 65,000 sq: cm, and includes a volume of 200 litres. Vacuum of the order of 1×10-7mbar is desired. To ensure a good vacuum gradient, distributive pumping is implemented. Electron beam is scanned to a size of 5cm × 120cm, to get a useful beam coverage, for industrial radiation applications. The beam is extracted through a window of Titanium foil of 50μm thickness. A safety interlock, to protect the electron gun, accelerating column and sputter ion pumps, in case of a foil rupture, is incorporated. Foil change can be done without disturbing the vacuum in the other zones. System will be integrated to a master control system to take care of the various safety aspects, and to make it operator friendly.

  6. Accelerating Cancer Systems Biology Research through Semantic Web Technology

    PubMed Central

    Wang, Zhihui; Sagotsky, Jonathan; Taylor, Thomas; Shironoshita, Patrick; Deisboeck, Thomas S.

    2012-01-01

    Cancer systems biology is an interdisciplinary, rapidly expanding research field in which collaborations are a critical means to advance the field. Yet the prevalent database technologies often isolate data rather than making it easily accessible. The Semantic Web has the potential to help facilitate web-based collaborative cancer research by presenting data in a manner that is self-descriptive, human and machine readable, and easily sharable. We have created a semantically linked online Digital Model Repository (DMR) for storing, managing, executing, annotating, and sharing computational cancer models. Within the DMR, distributed, multidisciplinary, and inter-organizational teams can collaborate on projects, without forfeiting intellectual property. This is achieved by the introduction of a new stakeholder to the collaboration workflow, the institutional licensing officer, part of the Technology Transfer Office. Furthermore, the DMR has achieved silver level compatibility with the National Cancer Institute’s caBIG®, so users can not only interact with the DMR through a web browser but also through a semantically annotated and secure web service. We also discuss the technology behind the DMR leveraging the Semantic Web, ontologies, and grid computing to provide secure inter-institutional collaboration on cancer modeling projects, online grid-based execution of shared models, and the collaboration workflow protecting researchers’ intellectual property. PMID:23188758

  7. Accelerating cancer systems biology research through Semantic Web technology.

    PubMed

    Wang, Zhihui; Sagotsky, Jonathan; Taylor, Thomas; Shironoshita, Patrick; Deisboeck, Thomas S

    2013-01-01

    Cancer systems biology is an interdisciplinary, rapidly expanding research field in which collaborations are a critical means to advance the field. Yet the prevalent database technologies often isolate data rather than making it easily accessible. The Semantic Web has the potential to help facilitate web-based collaborative cancer research by presenting data in a manner that is self-descriptive, human and machine readable, and easily sharable. We have created a semantically linked online Digital Model Repository (DMR) for storing, managing, executing, annotating, and sharing computational cancer models. Within the DMR, distributed, multidisciplinary, and inter-organizational teams can collaborate on projects, without forfeiting intellectual property. This is achieved by the introduction of a new stakeholder to the collaboration workflow, the institutional licensing officer, part of the Technology Transfer Office. Furthermore, the DMR has achieved silver level compatibility with the National Cancer Institute's caBIG, so users can interact with the DMR not only through a web browser but also through a semantically annotated and secure web service. We also discuss the technology behind the DMR leveraging the Semantic Web, ontologies, and grid computing to provide secure inter-institutional collaboration on cancer modeling projects, online grid-based execution of shared models, and the collaboration workflow protecting researchers' intellectual property.

  8. Cooperative adaptive bidirectional control of a train platoon for efficient utility and string stability

    NASA Astrophysics Data System (ADS)

    Gao, Shi-Gen; Dong, Hai-Rong; Ning, Bin; Roberts, Clive; Chen, Lei; Sun, Xu-Bin

    2015-09-01

    This paper proposes cooperative adaptive control schemes for a train platoon to improve efficient utility and guarantee string stability. The control schemes are developed based on a bidirectional strategy, i.e., the information of proximal (preceding and following) trains is used in the controller design. Based on available proximal information (prox-info) of location, speed, and acceleration, a direct adaptive control is designed to maintain the tracking interval at the minimum safe distance. Based on available prox-info of location, an observer-based adaptive control is designed to achieve the same target, which alleviates the requirements of equipped sensors to measure prox-info of speed and acceleration. The developed schemes are capable of on-line estimating of the unknown system parameters and stabilizing the closed-loop system, the string stability of train platoon is guaranteed on the basis of Lyapunov stability theorem. Numerical simulation results are presented to verify the effectiveness of the proposed control laws. Project supported by the Beijing Jiaotong University Research Program, China (Grant No. RCS2014ZT18), the Fundamental Research Funds for Central Universities, China (Grant No. 2015JBZ007), and the National Natural Science Foundation of China (Grant Nos. 61233001, 61322307, and 61304196).

  9. Cosmic string wakes

    NASA Technical Reports Server (NTRS)

    Stebbins, Albert; Veeraraghavan, Shoba; Silk, Joseph; Brandenberger, Robert; Turok, Neil

    1987-01-01

    Accretion of matter onto wakes left behind by horizon-sized pieces of cosmic string is investigated, and the effects of wakes on the large-scale structure of the universe are determined. Accretion of cold matter onto wakes, the effects of a long string on fluids with finite velocity dispersion or sound speeds, the interactions between loops and wakes, and the conditions for wakes to survive disruption by loops are discussed. It is concluded that the most important wakes are those which were formed at the time of equal matter and radiation density. This leads to sheetlike overdense regions of galaxies with a mean separation in agreement with the scale of the bubbles of de Lapparent, Geller, and Huchra (1986). However, for the value of G(mu) favored from galaxy formation considerations in a universe with cold dark matter, a wake accretes matter from a distance of only about 1.5 Mpc, which is much less than the distance between the wakes.

  10. Number of cosmic string loops

    NASA Astrophysics Data System (ADS)

    Blanco-Pillado, Jose J.; Olum, Ken D.; Shlaer, Benjamin

    2014-01-01

    Using recent simulation results, we provide the mass and speed spectrum of cosmic string loops. This is the quantity of primary interest for many phenomenological signatures of cosmic strings, and it can be accurately predicted using recently acquired detailed knowledge of the loop production function. We emphasize that gravitational smoothing of long strings plays a negligible role in determining the total number of existing loops. We derive a bound on the string tension imposed by recent constraints on the stochastic gravitational wave background from pulsar timing arrays, finding Gμ ≤2.8×10-9. We also provide a derivation of the Boltzmann equation for cosmic string loops in the language of differential forms.

  11. Cosmic necklaces from string theory

    SciTech Connect

    Leblond, Louis; Wyman, Mark

    2007-06-15

    We present the properties of a cosmic superstring network in the scenario of flux compactification. An infinite family of strings, the (p,q) strings, are allowed to exist. The flux compactification leads to a string tension that is periodic in p. Monopoles, appearing here as beads on a string, are formed in certain interactions in such networks. This allows bare strings to become cosmic necklaces. We study network evolution in this scenario, outlining what conditions are necessary to reach a cosmologically viable scaling solution. We also analyze the physics of the beads on a cosmic necklace, and present general conditions for which they will be cosmologically safe, leaving the network's scaling undisturbed. In particular, we find that a large average loop size is sufficient for the beads to be cosmologically safe. Finally, we argue that loop formation will promote a scaling solution for the interbead distance in some situations.

  12. Accelerating Medical Research using the Swift Workflow System

    PubMed Central

    STEF-PRAUN, Tiberiu; CLIFFORD, Benjamin; FOSTER, Ian; HASSON, Uri; HATEGAN, Mihael; SMALL, Steven L.; WILDE, Michael; ZHAO, Yong

    2009-01-01

    Both medical research and clinical practice are starting to involve large quantities of data and to require large-scale computation, as a result of the digitization of many areas of medicine. For example, in brain research – the domain that we consider here – a single research study may require the repeated processing, using computationally demanding and complex applications, of thousands of files corresponding to hundreds of functional MRI studies. Execution efficiency demands the use of parallel or distributed computing, but few medical researchers have the time or expertise to write the necessary parallel programs. The Swift system addresses these concerns. A simple scripting language, SwiftScript, provides for the concise high-level specification of workflows that invoke various application programs on potentially large quantities of data. The Swift engine provides for the efficient execution of these workflows on sequential computers, parallel computers, and/or distributed grids that federate the computing resources of many sites. Last but not least, the Swift provenance catalog keeps track of all actions performed, addressing vital bookkeeping functions that so often cause difficulties in large computations. To illustrate the use of Swift for medical research, we describe its use for the analysis of functional MRI data as part of a research project examining the neurological mechanisms of recovery from aphasia after stroke. We show how SwiftScript is used to encode an application workflow, and present performance results that demonstrate our ability to achieve significant speedups on both a local parallel computing cluster and multiple parallel clusters at distributed sites. PMID:17476063

  13. Asynchronous data change notification between database server and accelerator controls system

    SciTech Connect

    Fu, W.; Morris, J.; Nemesure, S.

    2011-10-10

    Database data change notification (DCN) is a commonly used feature. Not all database management systems (DBMS) provide an explicit DCN mechanism. Even for those DBMS's which support DCN (such as Oracle and MS SQL server), some server side and/or client side programming may be required to make the DCN system work. This makes the setup of DCN between database server and interested clients tedious and time consuming. In accelerator control systems, there are many well established software client/server architectures (such as CDEV, EPICS, and ADO) that can be used to implement data reflection servers that transfer data asynchronously to any client using the standard SET/GET API. This paper describes a method for using such a data reflection server to set up asynchronous DCN (ADCN) between a DBMS and clients. This method works well for all DBMS systems which provide database trigger functionality. Asynchronous data change notification (ADCN) between database server and clients can be realized by combining the use of a database trigger mechanism, which is supported by major DBMS systems, with server processes that use client/server software architectures that are familiar in the accelerator controls community (such as EPICS, CDEV or ADO). This approach makes the ADCN system easy to set up and integrate into an accelerator controls system. Several ADCN systems have been set up and used in the RHIC-AGS controls system.

  14. Retrieving backbone string neighbors provides insights into structural modeling of membrane proteins.

    PubMed

    Sun, Jiang-Ming; Li, Tong-Hua; Cong, Pei-Sheng; Tang, Sheng-Nan; Xiong, Wen-Wei

    2012-07-01

    Identification of protein structural neighbors to a query is fundamental in structure and function prediction. Here we present BS-align, a systematic method to retrieve backbone string neighbors from primary sequences as templates for protein modeling. The backbone conformation of a protein is represented by the backbone string, as defined in Ramachandran space. The backbone string of a query can be accurately predicted by two innovative technologies: a knowledge-driven sequence alignment and encoding of a backbone string element profile. Then, the predicted backbone string is employed to align against a backbone string database and retrieve a set of backbone string neighbors. The backbone string neighbors were shown to be close to native structures of query proteins. BS-align was successfully employed to predict models of 10 membrane proteins with lengths ranging between 229 and 595 residues, and whose high-resolution structural determinations were difficult to elucidate both by experiment and prediction. The obtained TM-scores and root mean square deviations of the models confirmed that the models based on the backbone string neighbors retrieved by the BS-align were very close to the native membrane structures although the query and the neighbor shared a very low sequence identity. The backbone string system represents a new road for the prediction of protein structure from sequence, and suggests that the similarity of the backbone string would be more informative than describing a protein as belonging to a fold.

  15. Subcritical string and large N QCD

    SciTech Connect

    Thorn, Charles B.

    2008-10-15

    We pursue the possibility of using subcritical string theory in 4 spacetime dimensions to establish a string dual for large N QCD. In particular we study the even G-parity sector of the 4 dimensional Neveu-Schwarz dual resonance model as the natural candidate for this string theory. Our point of view is that the open string dynamics given by this model will determine the appropriate subcritical closed string theory, a tree level background of which should describe the sum of planar multiloop open string diagrams. We examine the one-loop open string diagram, which contains information about the closed string spectrum at weak coupling. Higher loop open string diagrams will be needed to determine closed string interactions. We also analyze the field theory limit of the one-loop open string diagram and recover the correct running coupling behavior of the limiting gauge theory.

  16. The NREL Outdoor Accelerated-Weathering Tracking System Photovoltaic Module Exposure Results

    SciTech Connect

    Basso, T. S.

    2000-01-01

    Status results are presented for the Outdoor Accelerated-Weathering Tracking System (OATS) first study on photovoltaic (PV) modules. Studies began in November 1997 on pairs of commercially available crystalline silicon and amorphous silicon (a-Si) PV modules kept at constant resistive load.

  17. Radiation Safety System of the B-Factory at the Stanford Linear Accelerator Center

    SciTech Connect

    Liu, James C.

    1998-10-12

    The radiation safety system (RSS) of the B-Factory accelerator facility at the Stanford Linear Accelerator Center (SLAC) is described. The RSS, which is designed to protect people from prompt radiation exposure due to beam operation, consists of the access control system (ACS) and the radiation containment system (RCS). The ACS prevents people from being exposed to the very high radiation levels inside a beamline shielding housing. The ACS consists of barriers, a standard entry module at every entrance, and beam stoppers. The RCS prevents people from being exposed to the radiation outside a shielding housing, due to either normal or abnormal operation. The RCS consists of power limiting devices, shielding, dump/collimator, and an active radiation monitor system. The inter-related system elements for the ACS and RCS, as well as the associated interlock network, are described. The policies and practices in setting up the RSS are also compared with the regulatory requirements.

  18. Temperature Profile of the Solution Vessel of an Accelerator-Driven Subcritical Fissile Solution System

    SciTech Connect

    Klein, Steven Karl; Determan, John C.

    2015-09-14

    Dynamic System Simulation (DSS) models of fissile solution systems have been developed and verified against a variety of historical configurations. DSS techniques have been applied specifically to subcritical accelerator-driven systems using fissile solution fuels of uranium. Initial DSS models were developed in DESIRE, a specialized simulation scripting language. In order to tailor the DSS models to specifically meet needs of system designers they were converted to a Visual Studio implementation, and one of these subsequently to National Instrument’s LabVIEW for human factors engineering and operator training. Specific operational characteristics of subcritical accelerator-driven systems have been examined using a DSS model tailored to this particular class using fissile fuel.

  19. Clean Time-Dependent String Backgrounds from Bubble Baths

    SciTech Connect

    Silverstein, Eva M

    2002-08-08

    We consider the set of controlled time-dependent backgrounds of general relativity and string theory describing ''bubbles of nothing'', obtained via double analytic continuation of black hole solutions. We analyze their quantum stability, uncover some novel features of their dynamics, identify their causal structure and observables, and compute their particle production spectrum. We present a general relation between squeezed states, such as those arising in cosmological particle creation, and nonlocal theories on the string worldsheet. The bubble backgrounds have various aspects in common with de Sitter space, Rindler space, and moving mirror systems, but constitute controlled solutions of general relativity and string theory with no external forces. They provide a useful theoretical laboratory for studying issues of observables in systems with cosmological horizons, particle creation, and time-dependent string perturbation theory.

  20. Space acceleration measurement system description and operations on the First Spacelab Life Sciences Mission

    NASA Technical Reports Server (NTRS)

    Delombard, Richard; Finley, Brian D.

    1991-01-01

    The Space Acceleration Measurement System (SAMS) project and flight units are briefly described. The SAMS operations during the STS-40 mission are summarized, and a preliminary look at some of the acceleration data from that mission are provided. The background and rationale for the SAMS project is described to better illustrate its goals. The functions and capabilities of each SAMS flight unit are first explained, then the STS-40 mission, the SAMS's function for that mission, and the preparation of the SAMS are described. Observations about the SAMS operations during the first SAMS mission are then discussed. Some sample data are presented illustrating several aspects of the mission's microgravity environment.

  1. Construction of a 300-keV compact ion microbeam system with a three-stage acceleration lens

    NASA Astrophysics Data System (ADS)

    Ishii, Yasuyuki; Ohkubo, Takeru; Kojima, Takuji; Kamiya, Tomihiro

    2014-08-01

    Hydrogen ion microbeams were experimentally formed at beam energies below 150 keV using a 300-keV compact microbeam system that was constructed at the Japan Atomic Energy Agency. This paper is a preliminary report on the performance of the three-stage acceleration lens used in the compact microbeam system. This system consists of a three-stage acceleration lens and a plasma-type ion source. Since the three-stage acceleration lens was designed to simultaneously accelerate and focus the ion beam, the compact microbeam system is only about 1-m high and can be placed in a small experimental room. To evaluate the effectiveness of the three-stage acceleration lens, experimentally measured beam sizes are compared with theoretically calculated ones. The calculated and measured beam sizes were consistent within 10%. This shows that the three-stage acceleration lens is effective as a focusing lens for forming microbeams.

  2. Exposure of Polymeric Glazing Materials Using NREL's Ultra-Accelerated Weathering System (UAWS)

    SciTech Connect

    Bingham, C.; Jorgensen, G.; Wylie, A.

    2010-01-01

    NREL's Ultra-Accelerated Weathering System (UAWS) selectively reflects and concentrates natural sunlight ultraviolet irradiance below 475 nm onto exposed samples to provide accelerated weathering of materials while keeping samples within realistic temperature limits. This paper will explain the design and implementation of the UAWS which allow it to simulate the effect of years of weathering in weeks of exposure. Exposure chamber design and instrumentation will be discussed for both a prototype UAWS used to test glazing samples as well as a commercial version of UAWS. Candidate polymeric glazing materials have been subjected to accelerated exposure testing at a light intensity level of up to 50 UV suns for an equivalent outdoor exposure in Miami, FL exceeding 15 years. Samples include an impact modified acrylic, fiberglass, and polycarbonate having several thin UV-screening coatings. Concurrent exposure is carried out for identical sample sets at two different temperatures to allow thermal effects to be quantified along with resistance to UV.

  3. Development of and flight results from the Space Acceleration Measurement System (SAMS)

    NASA Technical Reports Server (NTRS)

    Delombard, Richard; Finley, Brian D.; Baugher, Charles R.

    1992-01-01

    Described here is the development of and the flight results from the Space Acceleration Measurement System (SAMS) flight units used in the Orbiter middeck, Spacelab module, and the Orbitercargo bay. The SAMS units are general purpose microgravity accelerometers designed to support a variety of science experiments with microgravity acceleration measurements. A total of six flight units have been fabricated; four for use in the Orbiter middeck and Spacelab module, and two for use in the Orbiter cargo bay. The design of the units is briefly described. The initial two flights of SAMS units on STS-40 (June 1991) and STS-43 (August 1991) resulted in 371 megabytes and 2.6 gigabytes of data respectively. Analytical techniques developed to examine this quantity of acceleration data are described and sample plots of analyzed data are illustrated. Future missions for the SAMS units are listed.

  4. An accelerated iterative method for the dynamics of constrained multibody systems

    NASA Astrophysics Data System (ADS)

    Lee, Kisu

    1993-01-01

    An accelerated iterative method is suggested for the dynamic analysis of multibody systems consisting of interconnected rigid bodies. The Lagrange multipliers associated with the kinematic constraints are iteratively computed by the monotone reduction of the constraint error vector, and the resulting equations of motion are easily time-integrated by a well established ODE technique. The velocity and acceleration constraints as well as the position constraints are made to be satisfied at the joints at each time step. Exact solution is obtained without the time demanding procedures such as selection of the independent coordinates, decomposition of the constraint Jacobian matrix, and Newton Raphson iterations. An acceleration technique is employed for the faster convergence of the iterative scheme and the convergence analysis of the proposed iterative method is presented. Numerical solutions for the verification problems are presented to demonstrate the efficiency and accuracy of the suggested technique.

  5. The accelerated site technology deployment program presents the segmented gate system

    SciTech Connect

    PATTESON,RAYMOND; MAYNOR,DOUG; CALLAN,CONNIE

    2000-02-24

    The Department of Energy (DOE) is working to accelerate the acceptance and application of innovative technologies that improve the way the nation manages its environmental remediation problems. The DOE Office of Science and Technology established the Accelerated Site Technology Deployment Program (ASTD) to help accelerate the acceptance and implementation of new and innovative soil and ground water remediation technologies. Coordinated by the Department of Energy's Idaho Office, the ASTD Program reduces many of the classic barriers to the deployment of new technologies by involving government, industry, and regulatory agencies in the assessment, implementation, and validation of innovative technologies. The paper uses the example of the Segmented Gate System (SGS) to illustrate how the ASTD program works. The SGS was used to cost effectively separate clean and contaminated soil for four different radionuclides: plutonium, uranium, thorium, and cesium. Based on those results, it has been proposed to use the SGS at seven other DOE sites across the country.

  6. Effect of water load in human body systems upon tolerance to +Gz acceleration.

    PubMed

    Gembicka, D

    1989-01-01

    A possible improvement of +Gz acceleration tolerance, obtained in human subjects through administering specific volumes of water, viz. 7, 14 and 21 ml/kg body weight, to be drunk immediately before centrifuge examination in order to increase the volume of plasma, thus increasing the circulating blood volume, was the starting-point for this work. Two hundred healthy male subjects, aged 19.9 +/- 0.9, were classified in 4 main groups and 2 supplementary groups for examination. It was found that the water intake in volumes of 14 ml/kg body weight produced a significant mean increase in the acceleration tolerance of 0.8 G, and that of 21 ml/kg body weight improved acceleration tolerance by 1.1 G on the average. The increase tolerance to acceleration was maintained throughout a period of about 30 minutes (for 14 ml/kg body weight) up to approximately 50 minutes (for 21 ml/kg body weight). The favourable effect of water load in the body systems upon +Gz acceleration tolerance was probably due to the increase of plasma volume (by 5.24% and 6.98% for 14 and 21 ml/kg body weight, respectively). PMID:2485611

  7. Racquet string tension directly affects force experienced at the elbow: implications for the development of lateral epicondylitis in tennis players

    PubMed Central

    Mohandhas, Badri R; Makaram, Navnit; Drew, Tim S; Wang, Weijie; Arnold, Graham P

    2016-01-01

    Background Lateral epicondylitis (LE) occurs in almost half of all tennis players. Racket-string tension is considered to be an important factor influencing the development of LE. No literature yet exists that substantiates how string-tension affects force transmission to the elbow, as implicated in LE development. We establish a quantitative relationship between string-tension and elbow loading, analyzing tennis strokes using rackets with varying string-tensions. Methods Twenty recreational tennis players simulated backhand tennis strokes using three rackets strung at tensions of 200 N, 222 N and 245 N. Accelerometers recorded accelerations at the elbow, wrist and racket handle. Average peak acceleration was determined to correlate string-tension with elbow loading. Results Statistically significant differences (p < 0.05) were observed when average peak acceleration at the elbow at 200 N string-tension (acceleration of 5.58 m/s2) was compared with that at 222 N tension (acceleration of 6.83 m/s2) and 245 N tension (acceleration of 7.45 m/s2). The 200 N racket induced the least acceleration at the elbow. Conclusions Although parameters determining force transmission to the elbow during a tennis stroke are complex, the present study was able to control these parameters, isolating the effect of string-tension. Lower string-tensions transmit less force to the elbow in backhand strokes. Reducing string-tension should be considered favourably with respect to reducing the risk of developing LE. PMID:27583017

  8. A climbing string method for saddle point search.

    PubMed

    Ren, Weiqing; Vanden-Eijnden, Eric

    2013-04-01

    The string method originally proposed for the computation of minimum energy paths (MEPs) is modified to find saddle points around a given minimum on a potential energy landscape using the location of this minimum as only input. In the modified method the string is evolved by gradient flow in path space, with one of its end points fixed at the minimum and the other end point (the climbing image) evolving towards a saddle point according to a modified potential force in which the component of the potential force in the tangent direction of the string is reversed. The use of a string allows us to monitor the evolution of the climbing image and prevent its escape from the basin of attraction of the minimum. This guarantees that the string always converges towards a MEP connecting the minimum to a saddle point lying on the boundary of the basin of attraction of this minimum. The convergence of the climbing image to the saddle point can also be accelerated by an inexact Newton method in the late stage of the computation. The performance of the numerical method is illustrated using the example of a 7-atom cluster on a substrate. Comparison is made with the dimer method.

  9. The Foucault pendulum with an ideal elastic suspension string

    NASA Astrophysics Data System (ADS)

    Stanovnik, A.

    2006-03-01

    It is interesting and instructive to compare the precession of a Foucault pendulum, which has an inextensible suspension string, to the precession of an ideal elastic pendulum, for which the string force is proportional to string length (a harmonic oscillator). For the latter case, a simple derivation is presented of the bob trajectories as seen by the local observer on the rotating earth. It is shown that the initial precession rate is equal to the precession rate of the Foucault pendulum, and that the precession period is equal to the rotation period of the earth. The different precession period of the Foucault pendulum may therefore be seen as a cumulative effect of its inextensible suspension string, which constrains the motion of the bob. It is also shown that the initial angular acceleration of the oscillation plane of the ideal elastic pendulum is opposite for opposite initial azimuth angles. If any such difference were observed for a real Foucault pendulum, it might indicate the presence of effects due to elasticity of the suspension string. Another interesting application of the present derivation would be to the precession of the spring-mass oscillator.

  10. Power Converters Maximize Outputs Of Solar Cell Strings

    NASA Technical Reports Server (NTRS)

    Frederick, Martin E.; Jermakian, Joel B.

    1993-01-01

    Microprocessor-controlled dc-to-dc power converters devised to maximize power transferred from solar photovoltaic strings to storage batteries and other electrical loads. Converters help in utilizing large solar photovoltaic arrays most effectively with respect to cost, size, and weight. Main points of invention are: single controller used to control and optimize any number of "dumb" tracker units and strings independently; power maximized out of converters; and controller in system is microprocessor.

  11. DEVELOPMENT OF ACCELERATOR DATA REPORTING SYSTEM AND ITS APPLICATION TO TREND ANALYSIS OF BEAM CURRENT DATA

    SciTech Connect

    Padilla, M.J.; Blokland, W.

    2009-01-01

    Detailed ongoing information about the ion beam quality is crucial to the successful operation of the Spallation Neutron Source at Oak Ridge National Laboratory. In order to provide the highest possible neutron production time, ion beam quality is monitored to isolate possible problems or performance-related issues throughout the accelerator and accumulator ring. For example, beam current monitor (BCM) data is used to determine the quality of the beam transport through the accelerator. In this study, a reporting system infrastructure was implemented and used to generate a trend analysis report of the BCM data. The BCM data was analyzed to facilitate the identifi cation of monitor calibration issues, beam trends, beam abnormalities, beam deviations and overall beam quality. A comparison between transformed BCM report data and accelerator log entries shows promising results which represent correlations between the data and changes made within the accelerator. The BCM analysis report is one of many reports within a system that assist in providing overall beam quality information to facilitate successful beam operation. In future reports, additional data manipulation functions and analysis can be implemented and applied. Built-in and user-defi ned analytic functions are available throughout the reporting system and can be reused with new data.

  12. Host-based data acquisition system to control pulsed facilities of the accelerator

    NASA Astrophysics Data System (ADS)

    Zamriy, V. N.

    2016-09-01

    The report discusses development of the host-based system to carry out timed measurements and data acquisition for the control of pulsed facilities of the accelerator. We consider modes of timing and allocation of operations of channels and the system node. The time of any working cycle of the pulsed facilities, rate of a data flow and an amount of serviced channels are coordinated with operation characteristics of the system node. Estimations of the readout rate of the data and the waiting time demonstrate the system efficiency. The technique has been developed to provide checking of groups of pulse parameters and control the facilities of the linear accelerator of electrons LUE-200 of the neutron source IREN.

  13. Inter-string Bose-Einstein Correlations in Hadronic Z Decays using the L3 Detector at LEP

    SciTech Connect

    Wang Qin

    2006-04-11

    Inter-string Bose-Eintein correlations are studied in hadronic Z events at {radical}(s) = 91.2 GeV. Preliminary results are presented comparing 1-string and 2-string systems: 2-jet with 3-jet events and quark jets with gluon jets.

  14. 30 CFR 250.445 - What are the requirements for kelly valves, inside BOPs, and drill-string safety valves?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., inside BOPs, and drill-string safety valves? 250.445 Section 250.445 Mineral Resources BUREAU OF OCEAN...) System Requirements § 250.445 What are the requirements for kelly valves, inside BOPs, and drill-string... floor. You must be able to install an inside BOP for each size connection in the drill string; (f)...

  15. String bit models for superstring

    SciTech Connect

    Bergman, O.; Thorn, C.B.

    1995-12-31

    The authors extend the model of string as a polymer of string bits to the case of superstring. They mainly concentrate on type II-B superstring, with some discussion of the obstacles presented by not II-B superstring, together with possible strategies for surmounting them. As with previous work on bosonic string work within the light-cone gauge. The bit model possesses a good deal less symmetry than the continuous string theory. For one thing, the bit model is formulated as a Galilei invariant theory in (D {minus} 2) + 1 dimensional space-time. This means that Poincare invariance is reduced to the Galilei subgroup in D {minus} 2 space dimensions. Naturally the supersymmetry present in the bit model is likewise dramatically reduced. Continuous string can arise in the bit models with the formation of infinitely long polymers of string bits. Under the right circumstances (at the critical dimension) these polymers can behave as string moving in D dimensional space-time enjoying the full N = 2 Poincare supersymmetric dynamics of type II-B superstring.

  16. G-NetMon: a GPU-accelerated network performance monitoring system

    SciTech Connect

    Wu, Wenji; DeMar, Phil; Holmgren, Don; Singh, Amitoj; /Fermilab

    2011-06-01

    At Fermilab, we have prototyped a GPU-accelerated network performance monitoring system, called G-NetMon, to support large-scale scientific collaborations. In this work, we explore new opportunities in network traffic monitoring and analysis with GPUs. Our system exploits the data parallelism that exists within network flow data to provide fast analysis of bulk data movement between Fermilab and collaboration sites. Experiments demonstrate that our G-NetMon can rapidly detect sub-optimal bulk data movements.

  17. Wormholes in string theory

    SciTech Connect

    Lyons, A. ); Hawking, S.W. )

    1991-12-15

    We discuss the wormhole effective interactions in string theory, thought of as a sum over two-dimensional field theories on different world sheets. The effective interactions are calculated in the dilute wormhole approximation,'' initially by considering the Green's functions on higher-genus Riemann surfaces, and then by calculating the effect of a complete basis of wave functions on scattering amplitudes for a surface with a boundary. The sum over wormholes is equivalent to having a world sheet of trivial topology and summing over different space-time and matter-field backgrounds. To leading order these consist of the massless fluctuations, since the tachyon cancels out when a sum is done over different spin structures going through the wormhole. In this way we recover quantized general relativity as an effective theory, from a sum over field theories on higher-genus Riemann surfaces.

  18. A character string scanner

    NASA Technical Reports Server (NTRS)

    Enison, R. L.

    1971-01-01

    A computer program called Character String Scanner (CSS), is presented. It is designed to search a data set for any specified group of characters and then to flag this group. The output of the CSS program is a listing of the data set being searched with the specified group of characters being flagged by asterisks. Therefore, one may readily identify specific keywords, groups of keywords or specified lines of code internal to a computer program, in a program output, or in any other specific data set. Possible applications of this program include the automatic scan of an output data set for pertinent keyword data, the editing of a program to change the appearance of a certain word or group of words, and the conversion of a set of code to a different set of code.

  19. Supersymmetric string waves

    SciTech Connect

    Bergshoeff, E.A. ); Kallosh, R.; Ortin, T. )

    1993-06-15

    We present plane-wave-type solutions of the lowest-order superstring effective action which have unbroken space-time supersymmetries. They are given by a stringy generalization of the Brinkmann metric, dialton, axion, and gauge fields. Some conspiracy between the metric and the axion field is required. The [alpha][prime] stringy corrections to the effective on-shell action, to the equations of motion (and therefore to the solutions themselves), and to the supersymmetry transformations are shown to vanish for a special class of these solutions that we call supersymmetric string waves (SSW's). In the SSW solutions, there exists a conspiracy not only between the metric and the axion field, but also between the gauge fields and the metric, since the embedding of the spin connection in the gauge group is required.

  20. Dynamical evolution of cosmic strings

    SciTech Connect

    Bouchet, F.R.

    1988-05-11

    The author have studied by means of numerical simulations the dynamical evolution of a network of cosmic strings, both in the radiation and matter era. Our basic conclusion is that a scaling solution exists, i.e., the string energy density evolves as t/sup -2/. This means that the process by which long strings dump their energy into closed loops (which can gravitationally radiate away) is efficient enough to prevent the string domination over other forms of energy. This conclusion does not depend on the initial string energy density, nor on the various numerical parameters. On the other hand, the generated spectrum of loop sizes does depend on the value of our numerical lower cutoff (i.e., the minimum length of loop we allow to be chopped off the network). Furthermore, the network evolution is very different from what was assumed before), namely the creation of a few horizon sized loops per horizon volume and per hubble time, which subsequently fragment into about 10 smaller daughter loops. Rather, many tiny loops are directly cut from the network of infinite strings, and it appears that the only fundamental scale (the horizon) has been lost. This is probably because a fundamental ingredient had been overlooked, namely the kinks. These kinks are created in pairs at each intercommutation, and very rapidly, the long strings appear to be very kinky. Thus the number of long strings per horizon is still of the order of a few, but their total length is fairly large. Furthermore, a large number of kinks favors the formation of small loops, and their sizes might well be governed by the kink density along the long strings. Finally, we computed the two-point correlation function of the loops and found significant differences from the work of Turok.

  1. Towards a string formulation of vortex dynamics

    SciTech Connect

    Elsebeth Schroeder; Ola Toernkvist

    1998-01-01

    We derive an exact equation of motion for a non-relativistic vortex in two- and three-dimensional models with a complex field. The velocity is given in terms of gradients of the complex field at the vortex position. We discuss the problem of reducing the field dynamics to a closed dynamical system with non-locally interacting strings as the fundamental degrees of freedom.

  2. Closed string amplitudes as single-valued open string amplitudes

    NASA Astrophysics Data System (ADS)

    Stieberger, Stephan; Taylor, Tomasz R.

    2014-04-01

    We show that the single trace heterotic N-point tree-level gauge amplitude ANHET can be obtained from the corresponding type I amplitude ANI by the single-valued (sv) projection: ANHET=sv(ANI). This projection maps multiple zeta values to single-valued multiple zeta values. The latter represent a subclass of multiple zeta values originating from single-valued multiple polylogarithms at unity. Similar relations between open and closed string amplitudes or amplitudes of different string vacua can be established. As a consequence the α‧-expansion of a closed string amplitude is dictated by that of the corresponding open string amplitude. The combination of single-valued projections, Kawai-Lewellen-Tye relations and Mellin correspondence reveal a unity of all tree-level open and closed superstring amplitudes together with the maximally supersymmetric Yang-Mills and supergravity theories.

  3. Worldsheet geometries of ambitwistor string

    NASA Astrophysics Data System (ADS)

    Ohmori, Kantaro

    2015-06-01

    Mason and Skinner proposed the ambitwistor string theory which directly reproduces the formulas for the amplitudes of massless particles proposed by Cachazo, He and Yuan. In this paper we discuss geometries of the moduli space of worldsheets associated to the bosonic or the RNS ambitwistor string. Further, we investigate the factorization properties of the amplitudes when an internal momentum is near on-shell in the abstract CFT language. Along the way, we propose the existence of the ambitwistor strings with three or four fermionic worldsheet currents.

  4. Geometry, topology, and string theory

    SciTech Connect

    Varadarajan, Uday

    2003-07-10

    A variety of scenarios are considered which shed light upon the uses and limitations of classical geometric and topological notions in string theory. The primary focus is on situations in which D-brane or string probes of a given classical space-time see the geometry quite differently than one might naively expect. In particular, situations in which extra dimensions, non-commutative geometries as well as other non-local structures emerge are explored in detail. Further, a preliminary exploration of such issues in Lorentzian space-times with non-trivial causal structures within string theory is initiated.

  5. Centrifugal accelerator, system and method for removing unwanted layers from a surface

    DOEpatents

    Foster, Christopher A.; Fisher, Paul W.

    1995-01-01

    A cryoblasting process having a centrifugal accelerator for accelerating frozen pellets of argon or carbon dioxide toward a target area utilizes an accelerator throw wheel designed to induce, during operation, the creation of a low-friction gas bearing within internal passages of the wheel which would otherwise retard acceleration of the pellets as they move through the passages. An associated system and method for removing paint from a surface with cryoblasting techniques involves the treating, such as a preheating, of the painted surface to soften the paint prior to the impacting of frozen pellets thereagainst to increase the rate of paint removal. A system and method for producing large quantities of frozen pellets from a liquid material, such as liquid argon or carbon dioxide, for use in a cryoblasting process utilizes a chamber into which the liquid material is introduced in the form of a jet which disintegrates into droplets. A non-condensible gas, such as inert helium or air, is injected into the chamber at a controlled rate so that the droplets freeze into bodies of relatively high density.

  6. Perturbations from strings don't look like strings!

    NASA Technical Reports Server (NTRS)

    Albrecht, Andreas; Stebbins, Albert

    1991-01-01

    A systematic analysis is challenging popular ideas about perturbation from cosmic strings. One way in which the picture has changed is reviewed. It is concluded that, while the scaling properties of cosmic strings figure significantly in the analysis, care must be taken when thinking in terms of single time snapshots. The process of seeding density perturbations is not fundamentally localized in time, and this fact can wash out many of the details which appear in a single snapshot.

  7. Solving large-scale sparse eigenvalue problems and linear systems of equations for accelerator modeling

    SciTech Connect

    Gene Golub; Kwok Ko

    2009-03-30

    The solutions of sparse eigenvalue problems and linear systems constitute one of the key computational kernels in the discretization of partial differential equations for the modeling of linear accelerators. The computational challenges faced by existing techniques for solving those sparse eigenvalue problems and linear systems call for continuing research to improve on the algorithms so that ever increasing problem size as required by the physics application can be tackled. Under the support of this award, the filter algorithm for solving large sparse eigenvalue problems was developed at Stanford to address the computational difficulties in the previous methods with the goal to enable accelerator simulations on then the world largest unclassified supercomputer at NERSC for this class of problems. Specifically, a new method, the Hemitian skew-Hemitian splitting method, was proposed and researched as an improved method for solving linear systems with non-Hermitian positive definite and semidefinite matrices.

  8. An improved 8 GeV beam transport system for the Fermi National Accelerator Laboratory

    SciTech Connect

    Syphers, M.J.

    1987-06-01

    A new 8 GeV beam transport system between the Booster and Main Ring synchrotrons at the Fermi National Accelerator Laboratory is presented. The system was developed in an effort to improve the transverse phase space area occupied by the proton beam upon injection into the Main Ring accelerator. Problems with the original system are described and general methods of beamline design are formulated. Errors in the transverse properties of a beamline at the injection point of the second synchrotron and their effects on the region in transverse phase space occupied by a beam of particles are discussed. Results from the commissioning phase of the project are presented as well as measurements of the degree of phase space dilution generated by the transfer of 8 GeV protons from the Booster synchrotron to the Main Ring synchrotron.

  9. A Study of Cell-to-Cell Interactions and Degradation in Parallel Strings: Implications for the Battery Management System

    NASA Astrophysics Data System (ADS)

    Pastor-Fernández, C.; Bruen, T.; Widanage, W. D.; Gama-Valdez, M. A.; Marco, J.

    2016-10-01

    Vehicle battery systems are usually designed with a high number of cells connected in parallel to meet the stringent requirements of power and energy. The self-balancing characteristic of parallel cells allows a battery management system (BMS) to approximate the cells as one equivalent cell with a single state of health (SoH) value, estimated either as capacity fade (SoHE) or resistance increase (SoHP). A single SoH value is however not applicable if the initial SoH of each cell is different, which can occur when cell properties change due to inconsistent manufacturing processes or in-homogeneous operating environments. As such this work quantifies the convergence of SoHE and SoHP due to initial differences in cell SoH and examines the convergence factors. Four 3 Ah 18650 cells connected in parallel at 25 °C are aged by charging and discharging for 500 cycles. For an initial SoHE difference of 40% and SoHP difference of 45%, SoHE converge to 10% and SoHP to 30% by the end of the experiment. From this, a strong linear correlation between ΔSoHE and ΔSoHP is also observed. The results therefore imply that a BMS should consider a calibration strategy to accurately estimate the SoH of parallel cells until convergence is reached.

  10. Materials considerations for molten salt accelerator-based plutonium conversion systems

    NASA Astrophysics Data System (ADS)

    Distefano, J. R.; Devan, J. H.; Keiser, J. R.; Klueh, R. L.; Eatherly, W. P.

    1995-03-01

    Accelerator-driven transmutation technology (ADTT) refers to a concept for a system that uses a blanket assembly driven by a source of neutrons produced when high-energy protons from an accelerator strike a heavy metal target. One application for such a system is called Accelerator-Based Plutonium Conversion, or ABC. Currently, the version of this concept being proposed by the Los Alamos National Laboratory features a liquid lead target material and a blanket fuel of molten fluorides that contain plutonium. Thus, the materials to be used in such a system must have, in addition to adequate mechanical strength, corrosion resistance to molten lead, corrosion resistance to molten fluoride salts, and resistance to radiation damage. In this report the corrosion properties of liquid lead and the LiF-BeF2 molten salt system are reviewed in the context of candidate materials for the above application. Background information has been drawn from extensive past studies. The system operating temperature, type of protective environment, and oxidation potential of the salt are shown to be critical design considerations. Factors such as the generation of fission products and transmutation of salt components also significantly affect corrosion behavior, and procedures for inhibiting their effects are discussed. In view of the potential for extreme conditions relative to neutron fluxes and energies that can occur in an ADTT, a knowledge of radiation effects is a most important factor. Present information for potential materials selections is summarized.

  11. Materials considerations for molten salt accelerator-based plutonium conversion systems

    SciTech Connect

    DiStefano, J.R.; DeVan, J.H.; Keiser, J.R.; Klueh, R.L.; Eatherly, W.P.

    1995-02-01

    Accelerator-driven transmutation technology (ADTT) refers to a concept for a system that uses a blanket assembly driven by a source of neutrons produced when high-energy protons from an accelerator strike a heavy metal target. One application for such a system is called Accelerator-Based Plutonium Conversion, or ABC. Currently, the version of this concept being proposed by the Los Alamos National Laboratory features a liquid lead target material and a blanket fuel of molten fluorides that contain plutonium. Thus, the materials to be used in such a system must have, in addition to adequate mechanical strength, corrosion resistance to molten lead, corrosion resistance to molten fluoride salts, and resistance to radiation damage. In this report the corrosion properties of liquid lead and the LiF-BeF{sub 2} molten salt system are reviewed in the context of candidate materials for the above application. Background information has been drawn from extensive past studies. The system operating temperature, type of protective environment, and oxidation potential of the salt are shown to be critical design considerations. Factors such as the generation of fission products and transmutation of salt components also significantly affect corrosion behavior, and procedures for inhibiting their effects are discussed. In view of the potential for extreme conditions relative to neutron fluxes and energies that can occur in an ADTT, a knowledge of radiation effects is a most important factor. Present information for potential materials selections is summarized.

  12. Materials considerations for molten salt accelerator-based plutonium conversion systems

    SciTech Connect

    DiStefano, J.R.; DeVan, J.H.; Keiser, J.R.; Klueh, R.L.; Eatherly, W.P.

    1995-03-01

    Accelerator-driven transmutation technology (ADTT) refers to a concept for a system that uses a blanket assembly driven by a source of neutrons produced when high-energy protons from an accelerator strike a heavy metal target. One application for such a system is called Accelerator-Based Plutonium Conversion, or ABC. Currently, the version of this concept being proposed by the Los Alamos National Laboratory features a liquid lead target material and a blanket fuel of molten fluorides that contain plutonium. Thus, the materials to be used in such a system must have, in addition to adequate mechanical strength, corrosion resistance to molten lead, corrosion resistance to molten fluoride salts, and resistance to radiation damage. In this report the corrosion properties of liquid lead and the LiF-BeF{sub 2} molten salt system are reviewed in the context of candidate materials for the above application. Background information has been drawn from extensive past studies. The system operating temperature, type of protective environment, and oxidation potential of the salt are shown to be critical design considerations. Factors such as the generation of fission products and transmutation of salt components also significantly affect corrosion behavior, and procedures for inhibiting their effects are discussed. In view of the potential for extreme conditions relative to neutron fluxes and energies that can occur in an ADTT, a knowledge of radiation effects is a most important factor. Present information for potential materials selections is summarized.

  13. Chemistry technology base and fuel cycle of the Los Alamos accelerator-driven transmutation system

    SciTech Connect

    Williamson, M.A.

    1997-12-01

    This paper provides a brief overview of the Los Alamos accelerator-driven transmutation system, a description of the pyrochemistry technology base and the fuel cycle for the system. The pyrochemistry technology base consists of four processes: direct oxide reduction, reductive extraction, electrorefining, and electrowinning. Each process and its utility is described. The fuel cycle is described for a liquid metal-based system with the focus being the conversion of commercial spent nuclear fuel to fuel for the transmutation system. Fission product separation and actinide recycle processes are also described.

  14. Voltage compensation based calibration measurement of 3D-acceleration transducer in fall detection system for the elderly.

    PubMed

    Zheng, Li; Wang, Lu; He, Dianning; Geng, Ning; Geng, Ping; Guan, Dejun; Xu, Lisheng

    2014-01-01

    The fall detection algorithm, which can recognize the fall of human body by collecting the acceleration signals in different directions of the body, is an important part of fall detection system for the elderly. The system, however, may have errors during analyzing the acceleration signal, due to that the coordinate system of the transducer does not coincide with the one of human motion. Furthermore, voltage variation of the battery also influences the accuracy of the acceleration signal. Therefore, in this paper, a fall detection system based on the 3D-acceleration transducer MMA7260 is designed, which can calibrate the acceleration data through compensation of voltage and transformation of coordinates. Experiments illustrated that the proposed method can accurately transform the collected data from the coordinate system of the transducer to that of the human motion, and can recognize various postural changes in the course of the motion of human body.

  15. Cosmic string catalysis of skyrmion decay

    NASA Technical Reports Server (NTRS)

    Gregory, Ruth; Davis, Anne-Christine; Brandenberger, Robert

    1988-01-01

    The Callan-Witten picture is developed for monopole catalyzed skyrmion decay in order to analyze the corresponding cosmic string scenario. It is discovered that cosmic strings (both ordinary and superconducting) can catalyze proton decay, but that this catalysis only occurs on the scale of the core of the string. In order to do this we have to develop a vortex model for the superconducting string. An argument is also given for the difference in the enhancement factors for monopoles and strings.

  16. Classification of cohomogeneity-one strings

    SciTech Connect

    Ishihara, Hideki; Kozaki, Hiroshi

    2005-09-15

    We define the cohomogeneity one string, string with continuous symmetries, as its world surface is tangent to a Killing vector field of a target space. We classify the Killing vector fields by an equivalence relation using isometries of the target space. We find that the equivalence classes of Killing vectors in Minkowski spacetime are partitioned into seven families. It is clarified that there exist seven types of strings with spacelike symmetries and four types of strings with timelike symmetries, stationary strings.

  17. Charting the landscape of supercritical string theory.

    PubMed

    Hellerman, Simeon; Swanson, Ian

    2007-10-26

    Special solutions of string theory in supercritical dimensions can interpolate in time between theories with different numbers of spacetime dimensions and different amounts of world sheet supersymmetry. These solutions connect supercritical string theories to the more familiar string duality web in ten dimensions and provide a precise link between supersymmetric and purely bosonic string theories. Dimension quenching and c duality appear to be natural concepts in string theory, giving rise to large networks of interconnected theories.

  18. Gravitating non-Abelian cosmic strings

    NASA Astrophysics Data System (ADS)

    de Pádua Santos, Antônio; Bezerra de Mello, Eugênio R.

    2015-08-01

    In this paper, we study regular cosmic string solutions of the non-Abelian Higgs model coupled with gravity. In order to develop this analysis, we constructed a set of coupled non-linear differential equations. Because there is no closed solution for this set of equations, we solve it numerically. The solutions we are interested in asymptote to a flat spacetime with a planar angle deficit. The model under consideration presents two bosonic sectors, besides the non-Abelian gauge field. The two bosonic sectors may present a direct coupling, so we investigate the relevance of this coupling on the system, specifically in the linear energy density of the string and on the planar angle deficit. We also analyze the behaviors of these quantities as a function of the energy scale where the gauge symmetry is spontaneously broken.

  19. Modeling Regular Replacement for String Constraint Solving

    NASA Technical Reports Server (NTRS)

    Fu, Xiang; Li, Chung-Chih

    2010-01-01

    Bugs in user input sanitation of software systems often lead to vulnerabilities. Among them many are caused by improper use of regular replacement. This paper presents a precise modeling of various semantics of regular substitution, such as the declarative, finite, greedy, and reluctant, using finite state transducers (FST). By projecting an FST to its input/output tapes, we are able to solve atomic string constraints, which can be applied to both the forward and backward image computation in model checking and symbolic execution of text processing programs. We report several interesting discoveries, e.g., certain fragments of the general problem can be handled using less expressive deterministic FST. A compact representation of FST is implemented in SUSHI, a string constraint solver. It is applied to detecting vulnerabilities in web applications

  20. String theory realizations of the nilpotent goldstino

    NASA Astrophysics Data System (ADS)

    Kallosh, Renata; Quevedo, Fernando; Uranga, Angel M.

    2015-12-01

    We describe in detail how the spectrum of a single anti-D3-brane in four-dimensional orientifolded IIB string models reproduces precisely the field content of a nilpotent chiral superfield with the only physical component corresponding to the fermionic goldstino. In particular we explicitly consider a single anti-D3-brane on top of an O3-plane in warped throats, induced by (2, 1) fluxes. More general systems including several anti-branes and other orientifold planes are also discussed. This provides further evidence to the claim that non-linearly realized supersymmetry due to the presence of antibranes in string theory can be described by supersymmetric theories including nilpotent superfields. Implications to the KKLT and related scenarios of de Sitter moduli stabilization, to cosmology and to the structure of soft SUSY-breaking terms are briefly discussed.

  1. Instantons and chiral symmetry in string theory

    NASA Astrophysics Data System (ADS)

    Jensen, Steuard B.

    The study of non-perturbative effects has played an important role in many recent developments in physics. String theory has proven to be an especially fertile ground for such studies: not only is its own non-perturbative structure interesting, but it has emerged as a framework in which to study the strongly coupled behavior of a variety of models in quantum field theory as well. In this thesis, I present results demonstrating the use of string theory in both these ways. First, I discuss non-perturbative corrections to the Kaluza-Klein monopole in string theory. As usually described, this object has an isometry around a compact circle and is related by T-duality to a "smeared" NS5-brane which retains that isometry. The true NS5-brane solution is localized at a point on the circle, so duality implies that the Kaluza-Klein monopole should show some corresponding behavior. By expressing the Kaluza-Klein monopole as a gauged linear sigma model in two dimensions, I show that worldsheet instantons give corrections to its geometry. These corrections can be understood as a localization in "winding space" which could be probed by strings with winding charge around the circle. Second, I discuss a configuration of D-branes in string theory whose low energy physics corresponds to a 3+1-dimensional quantum field theory with dynamically broken chiral symmetry. In a weakly coupled region of parameter space, this theory is a non-local generalization of the Nambu-Jona-Lasinio model. Indications are given that this model dynamically breaks chiral symmetry at arbitrarily weak 't Hooft coupling. At strong coupling this field theory is no longer solvable directly, but an alternate weakly coupled description can be found from the string theory model: the dynamics is determined by replacing a stack of D-branes by their near-horizon geometry and studying the low energy theory on probe D-branes in that background. In yet another region of parameter space, this D-brane configuration gives

  2. String and Sticky Tape Experiments.

    ERIC Educational Resources Information Center

    Edge, R. D., Ed.

    1979-01-01

    Explains how to demonstrate the fundamentals of one dimensional kinematics such as Newton's third law of motion, and collision between bodies, using simple materials of marbles, strings, sticky tape, drinking straws, and rubber bands. (GA)

  3. Spin chains and string theory.

    PubMed

    Kruczenski, Martin

    2004-10-15

    Recently, an important test of the anti de Sitter/conformal field theory correspondence has been done using rotating strings with two angular momenta. We show that such a test can be described more generally as the agreement between two actions: one a low energy description of a spin chain appearing in the field theory side, and the other a limit of the string action in AdS5xS5. This gives a map between the mean value of the spin in the boundary theory and the position of the string in the bulk, and shows how a string action can emerge from a gauge theory in the large-N limit.

  4. Performance of drill string hardfacings

    SciTech Connect

    Williamson, J.S.; Bolton, J.

    1984-06-01

    Drill string hardfacings are composites of steel and tungsten carbide applied by welding techniques. This paper discusses the important variables involved and gives experimental results for casing wear and abrasive wear resistance.

  5. Nuclear Force from String Theory

    NASA Astrophysics Data System (ADS)

    Hashimoto, Koji

    2010-04-01

    Recent "technology" called holography, or gauge/string duality (AdS/CFT correspondence) found in string theory, makes it possible to compute various quantities of strongly coupled gauge theories. This technology was applied to QCD, and it was found that it describes surprisingly well important properties of low energy QCD, the hadron physics. We apply it further to nuclear physics. In this talk, I review a part of the developments of the holographic QCD, and show a computation of nuclear force at short distance, derived using the holographic QCD, which was done in collaboration with T. Sakai and S. Sugimoto [K. Hashimoto, T. Sakai, and S. Sugimoto, "Holographic Baryons: Static Properties and Form Factors from Gauge/String Duality," Prog. Theor. Phys. 120 (2008) 1093-1137, arXiv:0806.3122 [hep-th]; K. Hashimoto, T. Sakai, and S. Sugimoto, "Nuclear Force from String Theory," arXiv:0901.4449 [hep-th

  6. Dynamical analysis of an accelerator-based fluid-fueled subcritical radioactive waste burning system

    NASA Astrophysics Data System (ADS)

    Woosley, Michael Louis, Jr.

    The recent revival of interest in accelerator-driven subcritical fluid-fueled systems is documented. Several important applications of these systems are mentioned. In particular, new applications have focused on the destruction of high-level radioactive waste. Systems can be designed to quickly destroy the actinides and long-lived fission products from light water reactor fuel, weapons plutonium, and other high-level defense wastes. The proposed development of these systems is used to motivate the need for the development of dynamic analysis methods for their nuclear kinetics. A physical description of the Los Alamos Accelerator-Based Conversion (ABC) concept is provided. This system is used as the basis for the kinetics study in this research. The current approach to the dynamic simulation of an accelerator-driven subcritical fluid-fueled system includes three elements: A discrete ordinates model is used to calculate the flux distribution for the source-driven system; A nodal convection model is used to calculate time-dependent isotope and temperature distributions which impact reactivity; A nodal importance weighting model is used to calculate the reactivity impact of temperature and isotope distributions and to feed this information back to the time-dependent nodal convection model. Specific transients which have been analyzed with the current modeling system are discussed. These transients include loss-of-flow and loss-of-cooling accidents, xenon and samarium transients, and cold-plug and overfueling events. The results of various transients have uncovered unpredictable behavior, unresolved design issues, and the need for active control. Modest initiating events can cause significant swings in system temperature and power. The circulation of the fluid fuel can lead to oscillations on the relatively short scale of the loop circulation time. The system responds quickly to reactivity changes because the large neutron source overwhelms the damping effect of delayed

  7. Requirements and Development of an Acceleration Measurement System for International Space Station Microgravity Science Payloads

    NASA Technical Reports Server (NTRS)

    Sutliff, Thomas J.

    1997-01-01

    The International Space Station is being developed by NASA and international partners as a versatile user platform to allow long term on-orbit investigations of a variety of scientific and technology arenas. In particular, scientific studies are planned within a research class known as microgravity science in areas such as biotechnology, combustion, fluid physics, and materials sciences. An acceleration measurement system is in development to aid such research conducted in the on-orbit conditions of apparent weightlessness. This system provides a general purpose acceleration measurement capability in support of these payloads and investigators. Such capability allows for systematic study of scientific phenomena by obtaining information regarding the local accelerations present during experiment operations. Preparations for implementing this flight measurement system involves two distinct stages: requirements development prior to initiating the design activity, and the design activity itself. This paper defines the requirements definition approach taken, provides an overview of the results of the requirements phase, and outlines the initial design considerations being addressed for this measurement system. Some preliminary engineering approaches are also described.

  8. String resonances at hadron colliders

    NASA Astrophysics Data System (ADS)

    Anchordoqui, Luis A.; Antoniadis, Ignatios; Dai, De-Chang; Feng, Wan-Zhe; Goldberg, Haim; Huang, Xing; Lüst, Dieter; Stojkovic, Dejan; Taylor, Tomasz R.

    2014-09-01

    We consider extensions of the standard model based on open strings ending on D-branes, with gauge bosons due to strings attached to stacks of D-branes and chiral matter due to strings stretching between intersecting D-branes. Assuming that the fundamental string mass scale Ms is in the TeV range and that the theory is weakly coupled, we discuss possible signals of string physics at the upcoming HL-LHC run (integrated luminosity =3000 fb-1) with a center-of-mass energy of √s =14 TeV and at potential future pp colliders, HE-LHC and VLHC, operating at √s =33 and 100 TeV, respectively (with the same integrated luminosity). In such D-brane constructions, the dominant contributions to full-fledged string amplitudes for all the common QCD parton subprocesses leading to dijets and γ +jet are completely independent of the details of compactification and can be evaluated in a parameter-free manner. We make use of these amplitudes evaluated near the first (n=1) and second (n=2) resonant poles to determine the discovery potential for Regge excitations of the quark, the gluon, and the color singlet living on the QCD stack. We show that for string scales as large as 7.1 TeV (6.1 TeV) lowest massive Regge excitations are open to discovery at the ≥5σ in dijet (γ +jet) HL-LHC data. We also show that for n=1 the dijet discovery potential at HE-LHC and VLHC exceedingly improves: up to 15 TeV and 41 TeV, respectively. To compute the signal-to-noise ratio for n=2 resonances, we first carry out a complete calculation of all relevant decay widths of the second massive level string states (including decays into massless particles and a massive n=1 and a massless particle), where we rely on factorization and conformal field theory techniques. Helicity wave functions of arbitrary higher spin massive bosons are also constructed. We demonstrate that for string scales Ms≲10.5 TeV (Ms≲28 TeV) detection of n =2 Regge recurrences at HE-LHC (VLHC) would become the smoking gun for D

  9. Design and Optimization of Large Accelerator Systems through High-Fidelity Electromagnetic Simulations

    SciTech Connect

    Ng, Cho; Akcelik, Volkan; Candel, Arno; Chen, Sheng; Ge, Lixin; Kabel, Andreas; Lee, Lie-Quan; Li, Zenghai; Prudencio, Ernesto; Schussman, Greg; Uplenchwar1, Ravi; Xiao1, Liling; Ko1, Kwok; Austin, T.; Cary, J.R.; Ovtchinnikov, S.; Smith, D.N.; Werner, G.R.; Bellantoni, L.; /SLAC /TechX Corp. /Fermilab

    2008-08-01

    SciDAC1, with its support for the 'Advanced Computing for 21st Century Accelerator Science and Technology' (AST) project, witnessed dramatic advances in electromagnetic (EM) simulations for the design and optimization of important accelerators across the Office of Science. In SciDAC2, EM simulations continue to play an important role in the 'Community Petascale Project for Accelerator Science and Simulation' (ComPASS), through close collaborations with SciDAC CETs/Institutes in computational science. Existing codes will be improved and new multi-physics tools will be developed to model large accelerator systems with unprecedented realism and high accuracy using computing resources at petascale. These tools aim at targeting the most challenging problems facing the ComPASS project. Supported by advances in computational science research, they have been successfully applied to the International Linear Collider (ILC) and the Large Hadron Collider (LHC) in High Energy Physics (HEP), the JLab 12-GeV Upgrade in Nuclear Physics (NP), as well as the Spallation Neutron Source (SNS) and the Linac Coherent Light Source (LCLS) in Basic Energy Sciences (BES).

  10. Modeling the dynamics of a compliant piano action mechanism impacting an elastic stiff string.

    PubMed

    Vyasarayani, Chandrika P; Birkett, Stephen; McPhee, John

    2009-06-01

    A realistic model of the piano hammer-string interaction must treat the action mechanism and string as a single system. In this paper an elastic stiff string model is integrated with a dynamic model of a compliant action mechanism with flexible hammer shank. Action components represented as rotating bodies interact through felt-lined interfaces for which a specialized contact model with hysteretic damping and tangential friction was developed. The motion of the hammer during string contact is governed by the dynamics of the action mechanism, thereby providing a more sophisticated hammer-string interaction than a simple transverse impact hammer model with fixed contact location. Simulations have been used to compare mechanism response for impact on the elastic string as compared to a rigid stop. Hammer head scuffing along the string and time in contact were predicted to increase, while hammer shank vibration amplitude and peak contact force were decreased. Introducing hammer-string friction decreases the duration of contact and reduces the extent of scuffing. Finally, significant differences in hammer and string motion were predicted for a highly flexible hammer shank. Initial contact time and location, length of contact period and peak force, hammer vibration amplitude, scuffing extent, and string spectral content were all influenced. PMID:19507984

  11. Modeling the dynamics of a compliant piano action mechanism impacting an elastic stiff string.

    PubMed

    Vyasarayani, Chandrika P; Birkett, Stephen; McPhee, John

    2009-06-01

    A realistic model of the piano hammer-string interaction must treat the action mechanism and string as a single system. In this paper an elastic stiff string model is integrated with a dynamic model of a compliant action mechanism with flexible hammer shank. Action components represented as rotating bodies interact through felt-lined interfaces for which a specialized contact model with hysteretic damping and tangential friction was developed. The motion of the hammer during string contact is governed by the dynamics of the action mechanism, thereby providing a more sophisticated hammer-string interaction than a simple transverse impact hammer model with fixed contact location. Simulations have been used to compare mechanism response for impact on the elastic string as compared to a rigid stop. Hammer head scuffing along the string and time in contact were predicted to increase, while hammer shank vibration amplitude and peak contact force were decreased. Introducing hammer-string friction decreases the duration of contact and reduces the extent of scuffing. Finally, significant differences in hammer and string motion were predicted for a highly flexible hammer shank. Initial contact time and location, length of contact period and peak force, hammer vibration amplitude, scuffing extent, and string spectral content were all influenced.

  12. The LLNL Accelerator Mass Spectrometry System for Biochemical 14C-Measurements

    SciTech Connect

    Ognibene, T J; Bench, G; Brown, T A; Vogel, J S

    2002-10-31

    We report on recent improvements made to our 1 MV accelerator mass spectrometry system that is dedicated to {sup 14}C quantification of biochemical samples. Increased vacuum pumping capacity near the high voltage terminal has resulted in a 2-fold reduction of system backgrounds to 0.04 amol {sup 14}C/mg carbon. Carbon ion transmission through the accelerator has also improved a few percent. We have also developed tritium measurement capability on this spectrometer. The {sup 3}H/{sup 1}H isotopic ratio of a milligram-sized processed tap water sample has been measured at 4 {+-} 1 x 10{sup -16} (430 {+-} 110 {micro}Bq/mg H). Measurement throughput for a typical biochemical {sup 3}H sample is estimated to be {approx}10 minutes/sample.

  13. A distributed control system status report of the munich accelerator control

    SciTech Connect

    Rohrer, L.; Schnitter, H.

    1999-04-26

    A system of computers connected by a local area network (ARCNET) controls the Munich accelerator facility. This includes ion sources, the tandem accelerator, the beam transport system, the gas handling plant, parts of experimental setup and also an ion source test bench. ARCNET is a deterministic multi-master network with arbitrary topology, using coax cables and optical fibers. Crates with single board computers and I/O-boards (analog, parallel or serial digital), dependent on the devices being controlled, are distributed all over the building. Personal computers serve as user interfaces. The LAN communication protocol is a client/server protocol. Communication language and programming language for the single board computers is Forth. The user mode drivers in the personal computers are also written in Forth. The tools for the operators are MS-Windows applications, programmed in Forth, C++ or Visual Basic. Links to MS-Office applications are available, too.

  14. Laser driven ion accelerator

    DOEpatents

    Tajima, Toshiki

    2006-04-18

    A system and method of accelerating ions in an accelerator to optimize the energy produced by a light source. Several parameters may be controlled in constructing a target used in the accelerator system to adjust performance of the accelerator system. These parameters include the material, thickness, geometry and surface of the target.

  15. Comparison of Lead-Bismuth and Lead as Coolants for Accelerator Driven Systems

    SciTech Connect

    Bianchi, F.; Mattioda, F.; Meloni, P.

    2002-07-01

    In the framework of the Italian research program TRASCO (TRAsmutazione SCOrie, namely transmutation of radioactive wastes) and of the European research program PDS-XADS (Preliminary Design Study on an eXperimental Accelerator Driven System) the feasibility and operability of gas or liquid metal cooled accelerator driven system prototypes are currently under investigation. Initially the attention of the thermal-hydraulics group of ENEA research centre in Bologna has been focussed toward a lead-bismuth cooled subcritical system under natural or enhanced natural circulation according to the prototype design proposed. The interest in using lead as a coolant, which is characterized by a higher melting point, is explained by the need to increase the plant efficiency for the economic competitiveness, though the higher temperatures pose some technological problems. Moreover, the amount of activation products should result significantly lower. Of course the results obtained and the experience gained analysing the dynamical behaviour of the lead-bismuth cooled system cannot be directly transferred to lead cooled systems. This paper aims at presenting a preliminary comparison of lead-bismuth and lead in a simplified liquid metal cooled subcritical system, mainly from the thermal-hydraulics and system dynamics points of view. By means of the modified RELAP5 version, the dynamical behavior of a lead-bismuth or lead cooled system, which is intended to be a quite accurate representation of the Italian accelerator driven prototype XADS, has been studied. Although a more exhaustive comparison should take into account the necessarily different structural characteristics of lead-bismuth and lead cooled systems, the neutronic feedback on reactor power and also the slightly different neutronic properties of lead-bismuth and lead, the purely thermal-hydraulic analysis presented in this paper has shown that the dynamical behaviour of the XADS does not differ noticeable when lead is used

  16. Geometric precipices in string cosmology

    SciTech Connect

    Kaloper, Nemanja; Watson, Scott

    2008-03-15

    We consider the effects of graviton multiplet fields on transitions between string gas phases. Focusing on the dilaton field, we show that it may obstruct transitions between different thermodynamic phases of the string gas, because the sign of its dimensionally reduced, T-duality invariant, part is conserved when the energy density of the Universe is positive. Thus, many interesting solutions for which this sign is positive end up in a future curvature singularity. Because of this, some of the thermodynamic phases of the usual gravitating string gases behave like superselection sectors. For example, a past-regular Hagedorn phase and an expanding Friedmann-Robertson-Walker (FRW) phase dominated by string momentum modes cannot be smoothly connected in the framework of string cosmology with positive sources. The singularity separates them like a geometric precipice in the moduli space, preventing the dynamics of the theory from bridging across. Sources which simultaneously violate the positivity of energy and null energy condition (NEC) could modify these conclusions. We provide a quantitative measure of positivity of energy and NEC violations that would be necessary for such transitions. These effects must dominate the Universe at the moment of transition, altering the standard gas pictures. At present, it is not known how to construct such sources from first principles in string theory.

  17. String theory on the edge

    SciTech Connect

    Thorlacius, L.

    1989-01-01

    Open string vacuum configurations are described in terms of a one-dimensional field theory on the worldsheet boundary. The one-dimensional path integral has direct physical interpretation as a source term for closed string fields. This means that the vacuum divergences (Mobius infinities) of the path integral must be renormalized correctly. The author shows that reparametrization invariance Ward identities, apart from specifying the equations of motion of spacetime background gauge fields, also serve to fix the renormalization scheme of the vacuum divergences. He argues that vacuum configurations of open strings correspond to Caldeira-Leggett models of dissipative quantum mechanics (DQM) evaluated at a delocalization critical point. This connection reveals that critical DQM will manifest reparametrization invariance (inherited from the conformal invariance of string theory) rather than just scale invariance. This connection should open up new ways of constructing analytic and approximate solutions of open string theory (in particular, topological solitons such as monopoles and instantons). Type I superstring theory gives rise to a supersymmetric boundary field theory. Bose-Fermi cancellation eliminates vacuum divergences but the one-loop beta function remains the same as in the bosonic theory. Reparametrization invariance Ward identities dictate a boundary state normalization which yields consistent string-loop corrections to spacetime equations of motion, in both the periodic and anti-periodic fermion sectors.

  18. Investigation of Lead Target Nuclei Used on Accelerator-Driven Systems for Tritium Production

    NASA Astrophysics Data System (ADS)

    Tel, E.; Aydin, A.

    2012-02-01

    High-current proton accelerators are being researched at Los Alamos National Laboratory and other laboratories for accelerator production of tritium, transmuting long-lived radioactive waste into shorter-lived products, converting excess plutonium, and producing energy. These technologies make use of spallation neutrons produced in ( p,xn) and ( n,xn) nuclear reactions on high-Z targets. Through ( p,xn) and ( n,xn) nuclear reactions, neutrons are produced and are moderated by heavy water. These moderated neutrons are subsequently captured on 3He to produce tritium via the ( n,p) reaction. Tritium self-sufficiency must be maintained for a commercial fusion power plant. Rubbia succeeded in a proposal of a full scale demonstration plant of the Energy Amplifier. This plant is to be known the accelerator-driven system (ADS). The ADS can be used for production of neutrons in spallation neutron source and they can act as an intense neutron source in accelerator-driven subcritical reactors, capable of incinerating nuclear waste and of producing energy. Thorium and Uranium are nuclear fuels and Lead, Bismuth, Tungsten are the target nuclei in these reactor systems. The spallation targets can be Pb, Bi, W, etc. isotopes and these target material can be liquid or solid. Naturally Lead includes the 204Pb (%1.42), 206Pb (%24.1), 207Pb (%22.1) and 208Pb (%52.3) isotopes. The design of ADS systems and also a fusion-fission hybrid reactor systems require the knowledge of a wide range of better data. In this study, by using Hartree-Fock method with an effective nucleon-nucleon Skyrme interactions rms nuclear charge radii, rms nuclear mass radii, rms nuclear proton, neutron radii and neutron skin thickness were calculated for the 204, 206, 208Pb isotopes . The calculated results have been compared with those of the compiled experimental and theoretical values of other studies.

  19. High-intensity cyclotrons for radioisotope production and accelerator driven systems

    NASA Astrophysics Data System (ADS)

    Jongen, Y.; Vandeplassche, D.; Kleeven, W.; Beeckman, W.; Zaremba, S.; Lannoye, G.; Stichelbaut, F.

    2002-04-01

    IBA recently proposed a new method to extract high-intensity positive ion beams from a cyclotron based on the concept of auto-extraction. We review the design of a 14 MeV, multi-milliampere cyclotron using this new technology. IBA is also involved in the design of the accelerator system foreseen to drive the MYRRHA facility, a multipurpose neutron source developed jointly by SCK-CEN and IBA.

  20. Cavity control system advanced modeling and simulations for TESLA linear accelerator and free electron laser

    NASA Astrophysics Data System (ADS)

    Czarski, Tomasz; Romaniuk, Ryszard S.; Pozniak, Krzysztof T.; Simrock, Stefan

    2004-07-01

    The cavity control system for the TESLA -- TeV-Energy Superconducting Linear Accelerator project is initially introduced. The elementary analysis of the cavity resonator on RF (radio frequency) level and low level frequency with signal and power considerations is presented. For the field vector detection the digital signal processing is proposed. The electromechanical model concerning Lorentz force detuning is applied for analyzing the basic features of the system performance. For multiple cavities driven by one klystron the field vector sum control is considered. Simulink model implementation is developed to explore the feedback and feed-forward system operation and some experimental results for signals and power considerations are presented.

  1. Self-gravitating strings in 2+1 dimensions

    NASA Astrophysics Data System (ADS)

    Ben-Menahem, Shahar

    1993-05-01

    We present a family of classical spacetimes in 2+1 dimensions. Such a spacetime is produced by a Nambu-Goto self-gravitating string. Because of the special properties of three-dimensional gravity, the metric is completely described as a Minkowski space with two identified world sheets. In the flat limit, the standard string is recovered. The formalism is developed for an open string with massive end points, but applies to other boundary conditions as well. We consider another limit, where the string tension vanishes in geometrical units but the end masses produce finite deficit angles. In this limit, our open string reduces to the free-masses solution of Gott, which possesses closed timelike curves when the relative motion of the two masses is sufficiently rapid. It is shown that the induced world sheet Liouville mode obeys (-classically)- a sinh- or cosh-Gordon differential equation, which reduces to the Liouville equation in the flat limit. A quadratic-action formulation of this system is presented. The possibility and significance of quantizing the self-gravitating string is discussed.

  2. Development of an ion beam analyzing system for the KBSI heavy-ion accelerator

    NASA Astrophysics Data System (ADS)

    Bahng, Jungbae; Hong, Jonggi; Park, Jin Yong; Kim, Seong Jun; Ok, Jung-Woo; Choi, Seyong; Shin, Chang Seouk; Yoon, Jang-Hee; Won, Mi-Sook; Lee, Byoung-Seob; Kim, Eun-San

    2016-02-01

    The Korea Basic Science Institute (KBSI) has been developing a heavy ion accelerator system to accelerate high current, multi-charge state ions produced by a 28 GHz superconducting electron cyclotron ion source. A beam analyzing system as a part of the low energy beam transport apparatus was developed to select charged particles with desirable charge states from the ion beams. The desired species of ion, which is generated and extracted from the ECR ion source including various ion particles, can be selected by 90° dipole electromagnet. Due to the non-symmetrical structure in the coil as well as the non-linear permeability of the yoke material coil, a three dimensional analysis was carried out to confirm the design parameters. In this paper, we present the experimental results obtained as result of an analysis of KBSI accelerator. The effectiveness of beam selection was confirmed during the test of the analyzing system by injecting an ion beam from an ECR ion source.

  3. Accelerator systems and instrumentation for the NuMI neutrino beam

    NASA Astrophysics Data System (ADS)

    Zwaska, Robert Miles

    The Neutrinos at the Main Injector (NuMI) neutrino beam facility began operating at the Fermi National Accelerator Laboratory in 2005. NuMI produces an intense, muon-neutrino beam to a number of experiments. Fore most of these experiments is MINOS---the Main Injector Neutrino Oscillation Search---that uses two neutrino detectors in the beam, one at Fermilab and one in northern Minnesota, to investigate the phenomenon of neutrino oscillations. NuMI is a conventional, horn-focused neutrino beam. It is designed to accept a 400 kW, 120 GeV proton beam from the Fermilab Main Injector accelerator. The proton beam is steered onto a target, producing a secondary beam of mesons which are focused into a long evacuated volume where they decay to muons and neutrinos. Pulsed toroidal magnets (horns) focus an adjustable meson momentum range. Design of the beamline and its components is challenged by the 400 kW average proton beam power. To achieve such high proton power, the Fermilab Main Injector (MI) must store and accelerate ˜ 4x1013 protons per acceleration cycle. This requires the MI to be loaded with 6 or more batches of protons from the 8 GeV Booster accelerator. Such multiple-batch injection involves a synchronization of the two machines not previously required by the Fermilab accelerators. In this dissertation, we investigate timing errors that can arise between the two accelerators, and a feedback system which enables multiple Booster transfers into the Main Injector without significant loss of beam. Using this method of synchronous transfer, the Main Injector has delivered as many as 3x1013 protons per pulse to the NuMI beam. The instrumentation to assess the quality of the neutrino beam includes arrays of radiation-tolerant ionization chambers downstream of the decay volume. These arrays detect the remnant hadrons and tertiary muons produced with the neutrinos. This thesis discusses measurements using the arrays, including diagnostics of potential beam errors and

  4. Topological insulators and superconductors from string theory

    SciTech Connect

    Ryu, Shinsei; Takayanagi, Tadashi

    2010-10-15

    Topological insulators and superconductors in different spatial dimensions and with different discrete symmetries have been fully classified recently, revealing a periodic structure for the pattern of possible types of topological insulators and superconductors, both in terms of spatial dimensions and in terms of symmetry classes. It was proposed that K theory is behind the periodicity. On the other hand, D-branes, a solitonic object in string theory, are also known to be classified by K theory. In this paper, by inspecting low-energy effective field theories realized by two parallel D-branes, we establish a one-to-one correspondence between the K-theory classification of topological insulators/superconductors and D-brane charges. In addition, the string theory realization of topological insulators and superconductors comes naturally with gauge interactions, and the Wess-Zumino term of the D-branes gives rise to a gauge field theory of topological nature, such as ones with the Chern-Simons term or the {theta} term in various dimensions. This sheds light on topological insulators and superconductors beyond noninteracting systems, and the underlying topological field theory description thereof. In particular, our string theory realization includes the honeycomb lattice Kitaev model in two spatial dimensions, and its higher-dimensional extensions. Increasing the number of D-branes naturally leads to a realization of topological insulators and superconductors in terms of holography (AdS/CFT).

  5. Attenuation of sound waves in drill strings

    SciTech Connect

    Drumheller, D.S. )

    1993-10-01

    During drilling of deep wells, digital data are often transmitted from sensors located near the drill bit to the surface. Development of a new communication system with increased data capacity is of paramount importance to the drilling industry. Since steel drill strings are used, transmission of these data by elastic carrier waves traveling within the drill pipe is possible, but the potential communication range is uncertain. The problem is complicated by the presence of heavy-threaded tool joints every 10 m, which form a periodic structure and produce classical patterns of passbands and stop bands in the wave spectra. In this article, field measurements of the attenuation characteristics of a drill string in the Long Valley Scientific Well in Mammoth Lakes, California are presented. Wave propagation distances approach 2 km. A theoretical model is discussed which predicts the location, width, and attenuation of the passbands. Mode conversion between extensional and bending waves, and spurious reflections due to deviations in the periodic spacings of the tool joints are believed to be the sources of this attenuation. It is estimated that attenuation levels can be dramatically reduced by rearranging the individual pipes in the drill string according to length. 7 refs., 20 figs., 4 tabs.

  6. Lupus-prone mice as models to study xenobiotic-induced acceleration of systemic autoimmunity.

    PubMed Central

    Pollard, K M; Pearson, D L; Hultman, P; Hildebrandt, B; Kono, D H

    1999-01-01

    The linkage between xenobiotic exposures and autoimmune diseases remains to be clearly defined. However, recent studies have raised the possibility that both genetic and environmental factors act synergistically at several stages or checkpoints to influence disease pathogenesis in susceptible populations. These observations predict that individuals susceptible to spontaneous autoimmunity should be more susceptible following xenobiotic exposure by virtue of the presence of predisposing background genes. To test this possibility, mouse strains with differing genetic susceptibility to murine lupus were examined for acceleration of autoimmune features characteristic of spontaneous systemic autoimmune disease following exposure to the immunostimulatory metals nickel and mercury. Although NiCl(2) exposure did not exacerbate autoimmunity, HgCl(2) significantly accelerated systemic disease in a strain-dependent manner. Mercury-exposed (NZB X NZW)F1 mice had accelerated lymphoid hyperplasia, hypergammaglobulinemia, autoantibodies, and immune complex deposits. Mercury also exacerbated immunopathologic manifestations in MRL+/+ and MR -lpr mice. However, there was less disease acceleration in lpr mice compared with MRL+/+ mice, likely due to the fact that environmental factors are less critical for disease induction when there is strong genetic susceptibility. Non-major histocompatibility complex genes also contributed to mercury-exacerbated disease, as the nonautoimmune AKR mice, which are H-2 identical with the MRL, showed less immunopathology than either the MRL/lpr or MRL+/+ strains. This study demonstrates that genetic susceptibility to spontaneous systemic autoimmunity can be a predisposing factor for HgCl(2)-induced exacerbation of autoimmunity. Such genetic predisposition may have to be considered when assessing the immunotoxicity of xenobiotics. Additional comparative studies using autoimmune-prone and nonautoimmune mice strains with different genetic backgrounds will

  7. Improving linear accelerator service response with a real- time electronic event reporting system.

    PubMed

    Hoisak, Jeremy D P; Pawlicki, Todd; Kim, Gwe-Ya; Fletcher, Richard; Moore, Kevin L

    2014-09-08

    To track linear accelerator performance issues, an online event recording system was developed in-house for use by therapists and physicists to log the details of technical problems arising on our institution's four linear accelerators. In use since October 2010, the system was designed so that all clinical physicists would receive email notification when an event was logged. Starting in October 2012, we initiated a pilot project in collaboration with our linear accelerator vendor to explore a new model of service and support, in which event notifications were also sent electronically directly to dedicated engineers at the vendor's technical help desk, who then initiated a response to technical issues. Previously, technical issues were reported by telephone to the vendor's call center, which then disseminated information and coordinated a response with the Technical Support help desk and local service engineers. The purpose of this work was to investigate the improvements to clinical operations resulting from this new service model. The new and old service models were quantitatively compared by reviewing event logs and the oncology information system database in the nine months prior to and after initiation of the project. Here, we focus on events that resulted in an inoperative linear accelerator ("down" machine). Machine downtime, vendor response time, treatment cancellations, and event resolution were evaluated and compared over two equivalent time periods. In 389 clinical days, there were 119 machine-down events: 59 events before and 60 after introduction of the new model. In the new model, median time to service response decreased from 45 to 8 min, service engineer dispatch time decreased 44%, downtime per event decreased from 45 to 20 min, and treatment cancellations decreased 68%. The decreased vendor response time and reduced number of on-site visits by a service engineer resulted in decreased downtime and decreased patient treatment cancellations.

  8. Improving linear accelerator service response with a real- time electronic event reporting system.

    PubMed

    Hoisak, Jeremy D P; Pawlicki, Todd; Kim, Gwe-Ya; Fletcher, Richard; Moore, Kevin L

    2014-01-01

    To track linear accelerator performance issues, an online event recording system was developed in-house for use by therapists and physicists to log the details of technical problems arising on our institution's four linear accelerators. In use since October 2010, the system was designed so that all clinical physicists would receive email notification when an event was logged. Starting in October 2012, we initiated a pilot project in collaboration with our linear accelerator vendor to explore a new model of service and support, in which event notifications were also sent electronically directly to dedicated engineers at the vendor's technical help desk, who then initiated a response to technical issues. Previously, technical issues were reported by telephone to the vendor's call center, which then disseminated information and coordinated a response with the Technical Support help desk and local service engineers. The purpose of this work was to investigate the improvements to clinical operations resulting from this new service model. The new and old service models were quantitatively compared by reviewing event logs and the oncology information system database in the nine months prior to and after initiation of the project. Here, we focus on events that resulted in an inoperative linear accelerator ("down" machine). Machine downtime, vendor response time, treatment cancellations, and event resolution were evaluated and compared over two equivalent time periods. In 389 clinical days, there were 119 machine-down events: 59 events before and 60 after introduction of the new model. In the new model, median time to service response decreased from 45 to 8 min, service engineer dispatch time decreased 44%, downtime per event decreased from 45 to 20 min, and treatment cancellations decreased 68%. The decreased vendor response time and reduced number of on-site visits by a service engineer resulted in decreased downtime and decreased patient treatment cancellations. PMID

  9. Introducing a new paradigm for accelerators and large experimental apparatus control systems

    NASA Astrophysics Data System (ADS)

    Catani, L.; Zani, F.; Bisegni, C.; Di Pirro, G.; Foggetta, L.; Mazzitelli, G.; Stecchi, A.

    2012-11-01

    The integration of web technologies and web services has been, in the recent years, one of the major trends in upgrading and developing distributed control systems for accelerators and large experimental apparatuses. Usually, web technologies have been introduced to complement the control systems with smart add-ons and user friendly services or, for instance, to safely allow access to the control system to users from remote sites. Despite this still narrow spectrum of employment, some software technologies developed for high-performance web services, although originally intended and optimized for these particular applications, deserve some features suggesting a deeper integration in a control system and, eventually, their use to develop some of the control system’s core components. In this paper, we present the conceptual design of a new control system for a particle accelerator and associated machine data acquisition system, based on a synergic combination of a nonrelational key/value database and network distributed object caching. The use of these technologies, to implement respectively continuous data archiving and data distribution between components, brought about the definition of a new control system concept offering a number of interesting features such as a high level of abstraction of services and components and their integration in a framework that can be seen as a comprehensive service provider that both graphical user interface applications and front-end controllers join for accessing and, to some extent, expanding its functionalities.

  10. A table-top x-ray FEL based on a laser wakefield accelerator-undulator system

    SciTech Connect

    Nakajima, K.; Kawakubo, T.; Nakanishi, H.

    1995-12-31

    Ultrahigh-gradient electron acceleration has been confirmed owing to the laser wakefield acceleration mechanism driven by an intense short laser wakefield acceleration mechanism driven by an intense short laser pulse in an underdense plasma. The laser wakefield acceleration makes it possible to build a compact electron linac capable of producing an ultra-short bunched electron beam. While the accelerator is attributed to longitudinal wakefields, transverse wakefields simultaneously generated by a short laser pulse can serve as a plasma undulator with a very short wavelength equal to a half of the plasma wavelength. We propose a new FEL concept for X-rays based on a laser wakefield accelerator-undulator system driven by intense short laser pulses delivered from table-top terawatt lasers. The system is composed of the accelerator stage and the undulator stage in a table-top size. A low energy electron beam is accelerated an bunched into microbunches due to laser wakefields in the accelerator stage. A micro-bunched beam travelling to the opposite direction of driving laser pulses produces coherent X-ray radiation in the undulator stage. A practical configuration and its analyses are presented.

  11. Automatic Detection for JavaScript Obfuscation Attacks in Web Pages through String Pattern Analysis

    NASA Astrophysics Data System (ADS)

    Choi, Younghan; Kim, Taeghyoon; Choi, Seokjin; Lee, Cheolwon

    Recently, most of malicious web pages include obfuscated codes in order to circumvent the detection of signature-based detection systems. It is difficult to decide whether the sting is obfuscated because the shape of obfuscated strings are changed continuously. In this paper, we propose a novel methodology that can detect obfuscated strings in the malicious web pages. We extracted three metrics as rules for detecting obfuscated strings by analyzing patterns of normal and malicious JavaScript codes. They are N-gram, Entropy, and Word Size. N-gram checks how many each byte code is used in strings. Entropy checks distributed of used byte codes. Word size checks whether there is used very long string. Based on the metrics, we implemented a practical tool for our methodology and evaluated it using read malicious web pages. The experiment results showed that our methodology can detect obfuscated strings in web pages effectively.

  12. Capture, acceleration and bunching rf systems for the MEIC booster and storage rings

    SciTech Connect

    Wang, Shaoheng; Guo, Jiquan; Lin, Fanglei; Morozov, Vasiliy; Rimmer, Robert A.; Wang, Haipeng; Zhang, Yuhong

    2015-09-01

    The Medium-energy Electron Ion Collider (MEIC), proposed by Jefferson Lab, consists of a series of accelerators. The electron collider ring accepts electrons from CEBAF at energies from 3 to 12 GeV. Protons and ions are delivered to a booster and captured in a long bunch before being ramped and transferred to the ion collider ring. The ion collider ring accelerates a small number of long ion bunches to colliding energy before they are re-bunched into a high frequency train of very short bunches for colliding. Two sets of low frequency RF systems are needed for the long ion bunch energy ramping in the booster and ion collider ring. Another two sets of high frequency RF cavities are needed for re-bunching in the ion collider ring and compensating synchrotron radiation energy loss in the electron collider ring. The requirements from energy ramping, ion beam bunching, electron beam energy compensation, collective effects, beam loading and feedback capability, RF power capability, etc. are presented. The preliminary designs of these RF systems are presented. Concepts for the baseline cavity and RF station configurations are described, as well as some options that may allow more flexible injection and acceleration schemes.

  13. [Pharmacological correction of central nervous system function in exposure to Coriolis acceleration].

    PubMed

    Karkishchenko, N N; Dimitriadi, N A; Molchanovskiĭ, V V

    1986-01-01

    Healthy volunteers with a low vestibular tolerance were exposed to Coriolis acceleration. Potassium orotate, pyracetame and riboxine were used as prophylactic measures against disorders in the function of the vestibular apparatus and higher compartments of the higher nervous system. The central nervous function was assessed with respect to the spectral power of electroencephalograms, short-term memory and mental performance. Potassium orotate given at a dose of 40 mg/kg body weight/day during 12-14 days as well as pyracetame given at a dose of 30 mg/kg body weight/day during 3 or 7 days increased significantly statokinetic tolerance and produced a protective effect on the central nervous function against Coriolis acceleration.

  14. Approach to compact terawatt CO{sub 2} laser system for particle acceleration

    SciTech Connect

    Pogorelsky, I.V.; Kimura, W.D.; Fisher, C.H.; Kannari, F.; Kurnit, N.A.

    1994-11-01

    A compact table-top 20-GW 50-ps CO{sub 2} laser system is in operation for strong-field physics studies at the ATF. We propose scaling up of the picosecond CO{sub 2} laser to a terawatt peak power level to meet the requirements of advanced laser accelerators. Computer modeling shows that a relatively compact single-beam picosecond CO{sub 2} laser system with a high-pressure x-ray picosecond amplifier of a 10-cm aperture is potentially scalable to the {approximately}1-TW peak power level.

  15. Optimization of parameters for the inline-injection system at Brookhaven Accelerator Test Facility

    SciTech Connect

    Parsa, Z.; Ko, S.K.

    1995-10-01

    We present some of our parameter optimization results utilizing code PARMLEA, for the ATF Inline-Injection System. The new solenoid-Gun-Solenoid -- Drift-Linac Scheme would improve the beam quality needed for FEL and other experiments at ATF as compared to the beam quality of the original design injection system. To optimize the gain in the beam quality we have considered various parameters including the accelerating field gradient on the photoathode, the Solenoid field strengths, separation between the gun and entrance to the linac as well as the (type size) initial charge distributions. The effect of the changes in the parameters on the beam emittance is also given.

  16. Collisions of strings with Y junctions.

    PubMed

    Copeland, E J; Kibble, T W B; Steer, D A

    2006-07-14

    We study the dynamics of Nambu-Goto strings with junctions at which three strings meet. In particular, we exhibit one simple exact solution and examine the process of intercommuting of two straight strings in which they exchange partners but become joined by a third string. We show that there are important kinematical constraints on this process. The exchange cannot occur if the strings meet with very large relative velocity. This may have important implications for the evolution of cosmic superstring networks and non-Abelian string networks. PMID:16907431

  17. Cosmic String Global Superconducting Dirac Born Infeld

    NASA Astrophysics Data System (ADS)

    Ikrima, Ika; Ramadhan, Handhika S.; Mart, Terry

    2016-08-01

    Superconducting cosmic string possibly plays an important role in the formation of the universe structure. The physics of this phenomenon has been explored by studying the field theory in the string interior. Numerical solutions of superconducting strings with all relevant fields are presented in this paper. The field is constructed from a generalization of the usual field theory of superconducting global string, but the kinetic term consists of the Dirac Born Infeld (DBI). Some changes in the characteristic of the superconducting string DBI from the usual superconducting string case have been observed. The observation includes physical mechanism of all related fields.

  18. Validation of a new control system for Elekta accelerators facilitating continuously variable dose rate

    SciTech Connect

    Bertelsen, Anders; Lorenzen, Ebbe L.; Brink, Carsten

    2011-08-15

    Purpose: Elekta accelerators controlled by the current clinically used accelerator control system, Desktop 7.01 (D7), uses binned variable dose rate (BVDR) for volumetric modulated arc therapy (VMAT). The next version of the treatment control system (Integrity) supports continuously variable dose rate (CVDR) as well as BVDR. Using CVDR opposed to BVDR for VMAT has the potential of reducing the treatment time but may lead to lower dosimetric accuracy due to faster moving accelerator parts. Using D7 and a test version of Integrity, differences in ability to control the accelerator, treatment efficiency, and dosimetric accuracy between the two systems were investigated. Methods: Single parameter tests were designed to expose differences in the way the two systems control the movements of the accelerator. In these tests, either the jaws, multi leaf collimators (MLCs), or gantry moved at constant speed while the dose rate was changed in discrete steps. The positional errors of the moving component and dose rate were recorded using the control systems with a sampling frequency of 4 Hz. The clinical applicability of Integrity was tested using 15 clinically used VMAT plans (5 prostate, 5 H and N, and 5 lung) generated by the SmartArc algorithm in PINNACLE. The treatment time was measured from beam-on to beam-off and the accuracy of the dose delivery was assessed by comparing DELTA4 measurements and PINNACLE calculated doses using gamma evaluation. Results: The single parameter tests showed that Integrity had an improved feedback between gantry motion and dose rate at the slight expense of MLC control compared to D7. The single parameter test did not reveal any significant differences in the control of either jaws or backup jaws between the two systems. These differences in gantry and MLC control together with the use of CVDR gives a smoother Integrity VMAT delivery compared to D7 with less abrupt changes in accelerator motion. Gamma evaluation (2% of 2 Gy and 2 mm) of the

  19. LINEAR ACCELERATOR

    DOEpatents

    Christofilos, N.C.; Polk, I.J.

    1959-02-17

    Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.

  20. Acceleration of multiple solution of a boundary value problem involving a linear algebraic system

    NASA Astrophysics Data System (ADS)

    Gazizov, Talgat R.; Kuksenko, Sergey P.; Surovtsev, Roman S.

    2016-06-01

    Multiple solution of a boundary value problem that involves a linear algebraic system is considered. New approach to acceleration of the solution is proposed. The approach uses the structure of the linear system matrix. Particularly, location of entries in the right columns and low rows of the matrix, which undergo variation due to the computing in the range of parameters, is used to apply block LU decomposition. Application of the approach is considered on the example of multiple computing of the capacitance matrix by method of moments used in numerical electromagnetics. Expressions for analytic estimation of the acceleration are presented. Results of the numerical experiments for solution of 100 linear systems with matrix orders of 1000, 2000, 3000 and different relations of variated and constant entries of the matrix show that block LU decomposition can be effective for multiple solution of linear systems. The speed up compared to pointwise LU factorization increases (up to 15) for larger number and order of considered systems with lower number of variated entries.

  1. Development of Velocity Guidance Assistance System by Haptic Accelerator Pedal Reaction Force Control

    NASA Astrophysics Data System (ADS)

    Yin, Feilong; Hayashi, Ryuzo; Raksincharoensak, Pongsathorn; Nagai, Masao

    This research proposes a haptic velocity guidance assistance system for realizing eco-driving as well as enhancing traffic capacity by cooperating with ITS (Intelligent Transportation Systems). The proposed guidance system generates the desired accelerator pedal (abbreviated as pedal) stroke with respect to the desired velocity obtained from ITS considering vehicle dynamics, and provides the desired pedal stroke to the driver via a haptic pedal whose reaction force is controllable and guides the driver in order to trace the desired velocity in real time. The main purpose of this paper is to discuss the feasibility of the haptic velocity guidance. A haptic velocity guidance system for research is developed on the Driving Simulator of TUAT (DS), by attaching a low-inertia, low-friction motor to the pedal, which does not change the original characteristics of the original pedal when it is not operated, implementing an algorithm regarding the desired pedal stroke calculation and the reaction force controller. The haptic guidance maneuver is designed based on human pedal stepping experiments. A simple velocity profile with acceleration, deceleration and cruising is synthesized according to naturalistic driving for testing the proposed system. The experiment result of 9 drivers shows that the haptic guidance provides high accuracy and quick response in velocity tracking. These results prove that the haptic guidance is a promising velocity guidance method from the viewpoint of HMI (Human Machine Interface).

  2. Design Considerations of Fast Kicker Systems for High Intensity Proton Accelerators

    SciTech Connect

    Zhang, W; Sandberg, J; Parson, W M; Walstrom, P; Murray, M M; Cook, E; Hartouni, E

    2001-06-12

    In this paper, we discuss the specific issues related to the design of the Fast Kicker Systems for high intensity proton accelerators. To address these issues in the preliminary design stage can be critical since the fast kicker systems affect the machine lattice structure and overall design parameters. Main topics include system architecture, design strategy, beam current coupling, grounding, end user cost vs. system cost, reliability, redundancy and flexibility. Operating experience with the Alternating Gradient Synchrotron injection and extraction kicker systems at Brookhaven National Laboratory and their future upgrade is presented. Additionally, new conceptual designs of the extraction kicker for the Spallation Neutron Source at Oak Ridge and the Advanced Hydrotest Facility at Los Alamos are discussed.

  3. DESIGN CONSIDERATIONS OF FAST KICKER SYSTEMS FOR HIGH INTENSITY PROTON ACCELERATORS.

    SciTech Connect

    ZHANG,W.; SANDBERG,J.; PARSONS,W.M.; WALSTROM,P.; MURRAY,M.M.; COOK,E.; HARTOUNI,E.

    2001-06-17

    In this paper, we discuss the specific issues related to the design of the Fast Kicker Systems for high intensity proton accelerators. To address these issues in the preliminary design stage can be critical since the fast kicker systems affect the machine lattice structure and overall design parameters. Main topics include system architecture, design strategy, beam current coupling, grounding, end user cost vs. system cost, reliability, redundancy and flexibility. Operating experience with the Alternating Gradient Synchrotron injection and extraction kicker systems at Brookhaven National Laboratory and their future upgrade is presented. Additionally, new conceptual designs of the extraction kicker for the Spallation Neutron Source at Oak Ridge and the Advanced Hydrotest Facility at Los Alamos are discussed.

  4. Generating string solutions in BTZ

    NASA Astrophysics Data System (ADS)

    David, Justin R.; Kalousios, Chrysostomos; Sadhukhan, Abhishake

    2013-02-01

    Integrability of classical strings in the BTZ black hole enables the construction and study of classical string propagation in this background. We first apply the dressing method to obtain classical string solutions in the BTZ black hole. We dress time like geodesics in the BTZ black hole and obtain open string solutions which are pinned on the boundary at a single point and whose end points move on time like geodesics. These strings upon regularising their charge and spins have a dispersion relation similar to that of giant magnons. We then dress space like geodesics which start and end on the boundary of the BTZ black hole and obtain minimal surfaces which can penetrate the horizon of the black hole while being pinned at the boundary. Finally we embed the giant gluon solutions in the BTZ background in two different ways. They can be embedded as a spiral which contracts and expands touching the horizon or a spike which originates from the boundary and touches the horizon.

  5. Constraints on string networks with junctions

    SciTech Connect

    Copeland, E. J.; Kibble, T. W. B.; Steer, D. A.

    2007-03-15

    We consider the constraints on string networks with junctions in which the strings may all be different, as may be found, for example, in a network of (p,q) cosmic superstrings. We concentrate on three aspects of junction dynamics. First we consider the propagation of small-amplitude waves across a static three-string junction. Then, generalizing our earlier work, we determine the kinematic constraints on two colliding strings with different tensions. As before, the important conclusion is that strings do not always reconnect with a third string; they can pass straight through one another (or in the case of non-Abelian strings become stuck in an X configuration), the constraint depending on the angle at which the strings meet, on their relative velocity, and on the ratios of the string tensions. For example, if the two colliding strings have equal tensions, then for ultrarelativistic initial velocities they pass through one another. However, if their tensions are sufficiently different they can reconnect. Finally, we consider the global properties of junctions and strings in a network. Assuming that, in a network, the incoming waves at a junction are independently randomly distributed, we determine the root-mean-square (r.m.s.) velocities of strings and calculate the average speed at which a junction moves along each of the three strings from which it is formed. Our findings suggest that junction dynamics may be such as to preferentially remove the heavy strings from the network leaving a network of predominantly light strings. Furthermore the r.m.s. velocity of strings in a network with junctions is smaller than 1/{radical}(2), the result for conventional Nambu-Goto strings without junctions in Minkowski space-time.

  6. Cosmic strings from supersymmetric flat directions

    SciTech Connect

    Cui Yanou; Morrissey, David E.; Martin, Stephen P.; Wells, James D.

    2008-02-15

    Flat directions are a generic feature of the scalar potential in supersymmetric gauge field theories. They can arise, for example, from D-terms associated with an extra Abelian gauge symmetry. Even when supersymmetry is broken softly, there often remain directions in the scalar field space along which the potential is almost flat. Upon breaking a gauge symmetry along one of these almost-flat directions, cosmic strings may form. Relative to the standard cosmic string picture based on the Abelian Higgs model, these flat-direction cosmic strings have the extreme type-I properties of a thin gauge core surrounded by a much wider scalar field profile. We perform a comprehensive study of the microscopic, macroscopic, and observational characteristics of this class of strings. We find many differences from the standard string scenario, including stable higher winding-mode strings, the dynamical formation of higher mode strings from lower ones, and a resultant multitension scaling string network in the early universe. These strings are only moderately constrained by current observations, and their gravitational wave signatures may be detectable at future gravity wave detectors. Furthermore, there is the interesting but speculative prospect that the decays of cosmic string loops in the early universe could be a source of ultrahigh-energy cosmic rays or nonthermal dark matter. We also compare the observational signatures of flat-direction cosmic strings with those of ordinary cosmic strings as well as (p,q) cosmic strings motivated by superstring theory.

  7. Angular Impact Mitigation System for Bicycle Helmets to Reduce Head Acceleration and Risk of Traumatic Brain Injury

    PubMed Central

    Hansen, Kirk; Dau, Nathan; Feist, Florian; Deck, Caroline; Willinger, Rémy; Madey, Steven M.; Bottlang, Michael

    2013-01-01

    Angular acceleration of the head is a known cause of traumatic brain injury (TBI), but contemporary bicycle helmets lack dedicated mechanisms to mitigate angular acceleration. A novel Angular Impact Mitigation (AIM) system for bicycle helmets has been developed that employs an elastically suspended aluminum honeycomb liner to absorb linear acceleration in normal impacts as well as angular acceleration in oblique impacts. This study tested bicycle helmets with and without AIM technology to comparatively assess impact mitigation. Normal impact tests were performed to measure linear head acceleration. Oblique impact tests were performed to measure angular head acceleration and neck loading. Furthermore, acceleration histories of oblique impacts were analyzed in a computational head model to predict the resulting risk of TBI in the form of concussion and diffuse axonal injury (DAI). Compared to standard helmets, AIM helmets resulted in a 14% reduction in peak linear acceleration (p < 0.001), a 34% reduction in peak angular acceleration (p < 0.001), and a 22% to 32% reduction in neck loading (p < 0.001). Computational results predicted that AIM helmets reduced the risk of concussion and DAI by 27% and 44%, respectively. In conclusion, these results demonstrated that AIM technology could effectively improve impact mitigation compared to a contemporary expanded polystyrene-based bicycle helmet, and may enhance prevention of bicycle-related TBI. Further research is required. PMID:23770518

  8. Angular Impact Mitigation system for bicycle helmets to reduce head acceleration and risk of traumatic brain injury.

    PubMed

    Hansen, Kirk; Dau, Nathan; Feist, Florian; Deck, Caroline; Willinger, Rémy; Madey, Steven M; Bottlang, Michael

    2013-10-01

    Angular acceleration of the head is a known cause of traumatic brain injury (TBI), but contemporary bicycle helmets lack dedicated mechanisms to mitigate angular acceleration. A novel Angular Impact Mitigation (AIM) system for bicycle helmets has been developed that employs an elastically suspended aluminum honeycomb liner to absorb linear acceleration in normal impacts as well as angular acceleration in oblique impacts. This study tested bicycle helmets with and without AIM technology to comparatively assess impact mitigation. Normal impact tests were performed to measure linear head acceleration. Oblique impact tests were performed to measure angular head acceleration and neck loading. Furthermore, acceleration histories of oblique impacts were analyzed in a computational head model to predict the resulting risk of TBI in the form of concussion and diffuse axonal injury (DAI). Compared to standard helmets, AIM helmets resulted in a 14% reduction in peak linear acceleration (p<0.001), a 34% reduction in peak angular acceleration (p<0.001), and a 22-32% reduction in neck loading (p<0.001). Computational results predicted that AIM helmets reduced the risk of concussion and DAI by 27% and 44%, respectively. In conclusion, these results demonstrated that AIM technology could effectively improve impact mitigation compared to a contemporary expanded polystyrene-based bicycle helmet, and may enhance prevention of bicycle-related TBI. Further research is required.

  9. Orbit error correction on the high energy beam transport line at the KHIMA accelerator system

    NASA Astrophysics Data System (ADS)

    Park, Chawon; Yim, Heejoong; Hahn, Garam; An, Dong Hyun

    2016-09-01

    For the purpose of treatment of various cancers and medical research, a synchrotron based medical machine has been developed under the Korea Heavy Ion Medical Accelerator (KHIMA) project and is scheduled for use to treat patient at the beginning of 2018. The KHIMA synchrotron is designed to accelerate and extract carbon ion (proton) beams with various energies from 110 to 430 MeV/u (60 to 230 MeV). Studies on the lattice design and beam optics for the High Energy Beam Transport (HEBT) line at the KHIMA accelerator system have been carried out using the WinAgile and the MAD-X codes. Because magnetic field errors and misalignments introduce deviations from the design parameters, these error sources should be treated explicitly, and the sensitivity of the machine's lattice to different individual error sources should be considered. Various types of errors, both static and dynamic, have been taken into account and have been consequentially corrected with a dedicated correction algorithm by using the MAD-X program. Based on the error analysis, the optimized correction setup is decided, and the specifications for the correcting magnets of the HEBT lines are determined.

  10. Improvement of trace element analysis system using RIKEN electron cyclotron resonance ion source and linear accelerator

    SciTech Connect

    Kidera, M.; Nakagawa, T.; Takahashi, K.; Enomoto, S.; Igarashi, K.; Fujimaki, M.; Ikezawa, E.; Kamigaito, O.; Kase, M.; Goto, A.; Yano, Y.

    2006-03-15

    We have developed a new analytical system that consists of an electron cyclotron resonance ion source (RIKEN 18 GHz ECRIS) and a RIKEN heavy ion linear accelerator (RILAC). This system is called trace element analysis using electron cyclotron resonance ion source and RILAC (ECRIS-RILAC-TEA). ECRIS-RILAC-TEA has several advantages as described in the work of Kidera et al. [AIP Conf. Proc. 749, 85 (2005)]. However, many experimental results during the last several years revealed a few problems: (1) large background contamination in the ECRIS, particularly at the surface of the plasma chamber wall, (2) high counting of the ionization chamber and the data taking system that is monitored by the direct beam from the accelerator, and (3) difficulty in the selection of the pilot sample and pilot beam production from the ECRIS for the purpose of normalization. In order to overcome these problems, we conducted several test experiments over the past year. In this article, we report the experimental results in detail and future plans for improving this system.

  11. Evaluation of a new IR-guided system for mechanical QA of linear accelerators

    SciTech Connect

    Lyatskaya, Yulia; Kadam, Dnyanesh; Levitsky, Gennady; Hacker, Fred; Chin, Lee

    2008-11-15

    The authors report the development of a new procedure for mechanical quality assurance of linear accelerators using an infrared-guided system. The system consists of an infrared (IR) camera and an IR-reflective marker that can be attached to a gantry, a collimator, or a treatment table. The trace of this marker can be obtained in three dimensions (3D) for a full or partial rotation of the mechanical devices. The software is written to localize rotational axes of the gantry, collimator, and the treatment table based on the marker traces. The separation of these axes characterizes the size of the sphere defining the mechanical isocenter. Additional information on anomalies in gantry movement such as degree of gantry sag and hysteresis can also be obtained. An intrinsic uncertainty of the system to localize rotational axis is 0.35 mm or less. Tests on a linear accelerator demonstrated the ability of this system to detect the separation between rotational axes of less than 1 mm and to confirm orthogonality of the planes of gantry, collimator, and table rotation.

  12. Ambitwistor Strings in Four Dimensions

    NASA Astrophysics Data System (ADS)

    Geyer, Yvonne; Lipstein, Arthur E.; Mason, Lionel

    2014-08-01

    We develop ambitwistor string theories for four dimensions to obtain new formulas for tree-level gauge and gravity amplitudes with arbitrary amounts of supersymmetry. Ambitwistor space is the space of complex null geodesics in complexified Minkowski space, and in contrast to earlier ambitwistor strings, we use twistors rather than vectors to represent this space. Although superficially similar to the original twistor string theories of Witten, Berkovits, and Skinner, these theories differ in the assignment of world sheet spins of the fields, rely on both twistor and dual twistor representatives for the vertex operators, and use the ambitwistor procedure for calculating correlation functions. Our models are much more flexible, no longer requiring maximal supersymmetry, and the resulting formulas for amplitudes are simpler, having substantially reduced moduli. These are supported on the solutions to the scattering equations refined according to helicity and can be checked by comparison with corresponding formulas of Witten and of Cachazo and Skinner.

  13. Acoustic data transmission through a drill string

    DOEpatents

    Drumheller, D.S.

    1988-04-21

    Acoustical signals are transmitted through a drill string by canceling upward moving acoustical noise and by preconditioning the data in recognition of the comb filter impedance characteristics of the drill string. 5 figs.

  14. False beats in coupled piano string unisons

    NASA Astrophysics Data System (ADS)

    Capleton, Brian

    2004-02-01

    The behavior of a unison pair of piano strings coupled by the soundboard bridge, when one string has localized anisotropy in the reactive part of the bridge admittance for a given partial frequency, can be investigated using a theoretical matrix description. The anisotropy can cause what in piano tuning terminology is referred to as ``false beating'' in a partial of the single string. A mathematical model can be used to illustrate how ``mistunings'' between the strings of the unison (measured when the strings are sounding in isolation from each other) may theoretically arise as a consequence of the normal practice in piano tuning, of eliminating or reducing audible beating in the unison when both strings are sounding. ``False beats'' in a single string partial can be ``inherited'' by a partial of the coupled unison's spectrum, and mistunings between the strings can eliminate or reduce the appearance of this inheritance.

  15. False beats in coupled piano string unisons.

    PubMed

    Capleton, Brian

    2004-02-01

    The behavior of a unison pair of piano strings coupled by the soundboard bridge, when one string has localized anisotropy in the reactive part of the bridge admittance for a given partial frequency, can be investigated using a theoretical matrix description. The anisotropy can cause what in piano tuning terminology is referred to as "false beating" in a partial of the single string. A mathematical model can be used to illustrate how "mistunings" between the strings of the unison (measured when the strings are sounding in isolation from each other) may theoretically arise as a consequence of the normal practice in piano tuning, of eliminating or reducing audible beating in the unison when both strings are sounding. "False beats" in a single string partial can be "inherited" by a partial of the coupled unison's spectrum, and mistunings between the strings can eliminate or reduce the appearance of this inheritance. PMID:15000199

  16. String spectra near some null cosmological singularities

    SciTech Connect

    Madhu, Kallingalthodi; Narayan, K.

    2009-06-15

    We construct cosmological spacetimes with null Kasner-like singularities as purely gravitational solutions with no other background fields turned on. These can be recast as anisotropic plane-wave spacetimes by coordinate transformations. We analyze string quantization to find the spectrum of string modes in these backgrounds. The classical string modes can be solved for exactly in these time-dependent backgrounds, which enables a detailed study of the near-singularity string spectrum, (time-dependent) oscillator masses, and wave functions. We find that for low-lying string modes (finite oscillation number), the classical near-singularity string mode functions are nondivergent for various families of singularities. Furthermore, for any infinitesimal regularization of the vicinity of the singularity, we find a tower of string modes of ultrahigh oscillation number which propagate essentially freely in the background. The resulting picture suggests that string interactions are non-negligible near the singularity.

  17. Cosmic rays from cosmic strings with condensates

    SciTech Connect

    Vachaspati, Tanmay

    2010-02-15

    We revisit the production of cosmic rays by cusps on cosmic strings. If a scalar field ('Higgs') has a linear interaction with the string world sheet, such as would occur if there is a bosonic condensate on the string, cusps on string loops emit narrow beams of very high energy Higgses which then decay to give a flux of ultrahigh energy cosmic rays. The ultrahigh energy flux and the gamma to proton ratio agree with observations if the string scale is {approx}10{sup 13} GeV. The diffuse gamma ray and proton fluxes are well below current bounds. Strings that are lighter and have linear interactions with scalars produce an excess of direct and diffuse cosmic rays and are ruled out by observations, while heavier strings ({approx}10{sup 15} GeV) are constrained by their gravitational signatures. This leaves a narrow window of parameter space for the existence of cosmic strings with bosonic condensates.

  18. Metastable cosmic strings in realistic models

    SciTech Connect

    Holman, R.; Hsu, S.; Vachaspati, T.; Watkins, R. |

    1992-11-01

    The stability of the electroweak Z-string is investigated at high temperatures. The results show that, while finite temperature corrections can improve the stability of the Z-string, their effect is not strong enough to stabilize the Z-string in the standard electroweak model. Consequently, the Z-string will be unstable even under the conditions present during the electroweak phase transition. Phenomenologically viable models based on the gauge group SU(2){sub L} {times} SU(2) {sub R} {times} U(1){sub B-L} are then considered, and it is shown that metastable strings exist and are stable to small perturbations for a large region of the parameter space for these models. It is also shown that these strings are superconducting with bosonic charge carriers. The string superconductivity may be able to stabilize segments and loops against dynamical contraction. Possible implications of these strings for cosmology are discussed.

  19. Metastable cosmic strings in realistic models

    SciTech Connect

    Holman, R. . Dept. of Physics); Hsu, S. . Lyman Lab. of Physics); Vachaspati, T. . Dept. of Physics and Astronomy); Watkins, R. Fermi National Accelerator Lab., Batavia, IL )

    1992-01-01

    The stability of the electroweak Z-string is investigated at high temperatures. The results show that, while finite temperature corrections can improve the stability of the Z-string, their effect is not strong enough to stabilize the Z-string in the standard electroweak model. Consequently, the Z-string will be unstable even under the conditions present during the electroweak phase transition. Phenomenologically viable models based on the gauge group SU(2)[sub L] [times] SU(2) [sub R] [times] U(1)[sub B-L] are then considered, and it is shown that metastable strings exist and are stable to small perturbations for a large region of the parameter space for these models. It is also shown that these strings are superconducting with bosonic charge carriers. The string superconductivity may be able to stabilize segments and loops against dynamical contraction. Possible implications of these strings for cosmology are discussed.

  20. Energy and Momentum Transport in String Waves

    ERIC Educational Resources Information Center

    Juenker, D. W.

    1976-01-01

    Formulas are derived for the energy, momentum, and angular momentum transmitted by waves of arbitrary shape in an inextensible string by pure transverse waves in a string using Tait's procedure. (Author/CP)