On bent and semi-bent quadratic Boolean functions

DEFF Research Database (Denmark)

Charpin, P.; Pasalic, Enes; Tavernier, C.

2005-01-01

correlation and high nonlinearity. We say that such a sequence is generated by a semi-bent function. Some new families of such function, represented by f(x) = Sigma(i=1)(n-1/2) c(i)Tr(x(2t+1)), n odd and c(i) is an element of F-2, have recently (2002) been introduced by Khoo et al. We first generalize......The maximum-length sequences, also called m-sequences, have received a lot of attention since the late 1960s. In terms of linear-feedback shift register (LFSR) synthesis they are usually generated by certain power polynomials over a finite field and in addition are characterized by a low cross...... their results to even n. We further investigate the conditions on the choice of ci for explicit definitions of new infinite families having three and four trace terms. Also, a class of nonpermutation polynomials whose composition with a quadratic function yields again a quadratic semi-bent function is specified...

Heat exchanger tube tool

International Nuclear Information System (INIS)

Gugel, G.

1976-01-01

Certain types of heat-exchangers have tubes opening through a tube sheet to a manifold having an access opening offset from alignment with the tube ends. A tool for inserting a device, such as for inspection or repair, is provided for use in such instances. The tool is formed by a flexible guide tube insertable through the access opening and having an inner end provided with a connector for connection with the opening of the tube in which the device is to be inserted, and an outer end which remains outside of the chamber, the guide tube having adequate length for this arrangement. A flexible transport hose for internally transporting the device slides inside of the guide tube. This hose is long enough to slide through the guide tube, into the heat-exchanger tube, and through the latter to the extent required for the use of the device. The guide tube must be bent to reach the end of the heat-exchanger tube and the latter may be constructed with a bend, the hose carrying anit-friction elements at interspaced locations along its length to make it possible for the hose to negotiate such bends while sliding to the location where the use of the device is required

Bent functions results and applications to cryptography

CERN Document Server

Tokareva, Natalia

2015-01-01

Bent Functions: Results and Applications to Cryptography offers a unique survey of the objects of discrete mathematics known as Boolean bent functions. As these maximal, nonlinear Boolean functions and their generalizations have many theoretical and practical applications in combinatorics, coding theory, and cryptography, the text provides a detailed survey of their main results, presenting a systematic overview of their generalizations and applications, and considering open problems in classification and systematization of bent functions. The text is appropriate for novices and advanced

Self-sensing concrete-filled FRP tube using FBG strain sensor

Science.gov (United States)

Yan, Xin; Li, Hui

2007-01-01

Concrete-filled fiber-reinforced polymer (FRP) tube is a type of newly developed structural column. It behaves brittle failure at its peak strength, and so the health monitoring on the hoop strain of the FRP tube is essential for the life cycle safety of the structure. Herein, the optic fiber Bragg grating (FBG) strain sensor was chosen as the strain measuring gauge and embedded in the inter-ply of fibers in the middle height and the hoop direction of the FRP tube. The compressive behaviors of the concrete-filled FRP tubes were experimentally studied. The hoop strain of the FRP tube was recorded in real time using the embedded FBG strain sensor as well as the embedded or surface electric resistance strain gauges. Results indicated that the FBG strain sensor can faithfully record the hoop strain ofthe concrete-filled FRP tubes in compression as compared with the embedded or surface electric resistance strain gauges, and the strain recorded can reach more than 7000μɛ.

Failure of fretted steam generator tubes under accident conditions

International Nuclear Information System (INIS)

Forrest, C.F.

1996-10-01

Tests were carried out with a bank of tubes in a water tunnel to determine the tolerance of flawed nuclear reactor steam generator tubes to accident conditions which would result in high cross-flow velocities. Fourteen specimen tubes were tested, each having one or two types of defect machined into the surface simulating fretting-wear type scars found in some operating steam generators. The tubes were tested at flow velocities sufficient to induce high fluid elastic-type vibrations. Seven of the tubes failed near the thinnest section of the defects during the one-hour tests, due to impacting and/or rubbing between the tube and the support. Strain gauges, displacement transducers, force gauges and an accelerometer were used on the target tube and/or the tube immediately downstream of it to measure their vibrational characteristics

Intrinsically bent DNA in replication origins and gene promoters.

Science.gov (United States)

Gimenes, F; Takeda, K I; Fiorini, A; Gouveia, F S; Fernandez, M A

2008-06-24

Intrinsically bent DNA is an alternative conformation of the DNA molecule caused by the presence of dA/dT tracts, 2 to 6 bp long, in a helical turn phase DNA or with multiple intervals of 10 to 11 bp. Other than flexibility, intrinsic bending sites induce DNA curvature in particular chromosome regions such as replication origins and promoters. Intrinsically bent DNA sites are important in initiating DNA replication, and are sometimes found near to regions associated with the nuclear matrix. Many methods have been developed to localize bent sites, for example, circular permutation, computational analysis, and atomic force microscopy. This review discusses intrinsically bent DNA sites associated with replication origins and gene promoter regions in prokaryote and eukaryote cells. We also describe methods for identifying bent DNA sites for circular permutation and computational analysis.

Bent's Old Fort: Amphibians and Reptiles

Science.gov (United States)

Muths, E.

2008-01-01

Bent's Old Fort National Historic Site sits along the Arkansas River in the semi-desert prairie of southeastern Colorado. The USGS provided assistance in designing surveys to assess the variety of herpetofauna (amphibians and reptiles) resident at this site. This brochure is the results of those efforts and provides visitors with information on what frogs, toads, snakes and salamanders might be seen and heard at Bent's Old Fort.

REGULAR METHOD FOR SYNTHESIS OF BASIC BENT-SQUARES OF RANDOM ORDER

Directory of Open Access Journals (Sweden)

A. V. Sokolov

2016-01-01

Full Text Available The paper is devoted to the class construction of the most non-linear Boolean bent-functions of any length N = 2k (k = 2, 4, 6…, on the basis of their spectral representation – Agievich bent squares. These perfect algebraic constructions are used as a basis to build many new cryptographic primitives, such as generators of pseudo-random key sequences, crypto graphic S-boxes, etc. Bent-functions also find their application in the construction of C-codes in the systems with code division multiple access (CDMA to provide the lowest possible value of Peak-to-Average Power Ratio (PAPR k = 1, as well as for the construction of error-correcting codes and systems of orthogonal biphasic signals. All the numerous applications of bent-functions relate to the theory of their synthesis. However, regular methods for complete class synthesis of bent-functions of any length N = 2k are currently unknown. The paper proposes a regular synthesis method for the basic Agievich bent squares of any order n, based on a regular operator of dyadic shift. Classification for a complete set of spectral vectors of lengths (l = 8, 16, … based on a criterion of the maximum absolute value and set of absolute values of spectral components has been carried out in the paper. It has been shown that any spectral vector can be a basis for building bent squares. Results of the synthesis for the Agievich bent squares of order n = 8 have been generalized and it has been revealed that there are only 3 basic bent squares for this order, while the other 5 can be obtained with help the operation of step-cyclic shift. All the basic bent squares of order n = 16 have been synthesized that allows to construct the bent-functions of length N = 256. The obtained basic bent squares can be used either for direct synthesis of bent-functions and their practical application or for further research in order to synthesize new structures of bent squares of orders n = 16, 32, 64, …

Observation of a Coulomb flux tube

Science.gov (United States)

Greensite, Jeff; Chung, Kristian

2018-03-01

In Coulomb gauge there is a longitudinal color electric field associated with a static quark-antiquark pair. We have measured the spatial distribution of this field, and find that it falls off exponentially with transverse distance from a line joining the two quarks. In other words there is a Coulomb flux tube, with a width that is somewhat smaller than that of the minimal energy flux tube associated with the asymptotic string tension. A confinement criterion for gauge theories with matter fields is also proposed.

Calamitic Smectic A-Polar Smectic APA Transition Observed in Bent Molecules with Large Bent-Angle Central Core of 4,6-Dichlorobenzene and Alkylthio Terminal Tail

Science.gov (United States)

Nguyen, Ha; Kang, Sungmin; Tokita, Masatoshi; Watanabe, Junji

2011-07-01

New homologs of bent molecules with a large bent-angle central core of 4,6-dichloro benzene and an alkylthio terminal tail have been synthesized. Although the corresponding alkoxy-tail homologs show only the calamitic phases because of its large bent angles around 160°, the new homologs with an alkylthio tail exhibit the antiferroelectric smectic APA (SmAPA) banana phase that is transformed on cooling from the calamitic smectic A (SmA) phase. The biaxial polar packing of bent molecules in the SmAPA phase is considered to arise from the hindered rotation around the molecular long axis due to the expansion of the mesophase temperatures to a lower temperature region. This study indicates that the bent molecules, even with a large bent angle, have the potential to form a switchable banana phase with a remarkable decrease in its phase temperature range to around 60 °C.

Bent solenoids for spectrometers and emittance exchange sections

International Nuclear Information System (INIS)

Norem, J.

1999-01-01

Bent solenoids can be used to transport low energy beams as they provide both confinement and dispersion of particle orbits. Solenoids are being considered both as emittance exchange sections and spectrometers in the muon cooling system as part of the study of the muon collider. They present the results of a study of bent solenoids which considers the design of coupling sections between bent solenoids to straight solenoids, drift compensation fields, aberrations, and factors relating to the construction, such as field ripple, stored energy, coil forces and field errors

Gauging device

International Nuclear Information System (INIS)

Qurnell, F.D.; Patterson, C.B.

1979-01-01

A gauge supporting device for measuring say a square tube comprises a pair of rods or guides in tension between a pair of end members, the end members being spaced apart by a compression member or members. The tensioned guides provide planes of reference for measuring devices moved therealong on a carriage. The device is especially useful for making on site dimensional measurements of components, such as irradiated and therefore radioactive components, that cannot readily be transported to an inspection laboratory. (UK)

Beam-smiling in bent-Laue monochromators

International Nuclear Information System (INIS)

Ren, B.; Dilmanian, F. A.; Wu, X. Y.; Huang, X.; Chapman, L. D.; Ivanov, I.; Zhong, Z.; Thomlinson, W. C.

1997-01-01

When a wide fan-shaped x-ray beam is diffracted by a bent crystal in the Laue geometry, the profile of the diffracted beam generally does not appear as a straight line, but as a line with its ends curved up or curved down. This effect, referred to as 'beam-smiling', has been a major obstacle in developing bent-Laue crystal monochromators for medical applications of synchrotron x-ray. We modeled a cylindrically bent crystal using the Finite Element Analysis (FEA) method, and we carried out experiments at the National Synchrotron Light Source and Cornell High Energy Synchrotron Source. Our studies show that, while beam-smiling exists in most of the crystal's area because of anticlastic bending effects, there is a region parallel to the bending axis of the crystal where the diffracted beam is 'smile-free'. By applying asymmetrical bending, this smile-free region can be shifted vertically away from the geometric center of the crystal, as desired. This leads to a novel method of compensating for beam-smiling. We will discuss the method of ''differential bending'' for smile removal, beam-smiling in the Cauchios and the polychromatic geometry, and the implications of the method on developing single- and double-bent Laue monochromators. The experimental results will be discussed, concentrating on specific beam-smiling observation and removal as applied to the new monochromator of the Multiple Energy Computed Tomography [MECT] project of the Medical Department, Brookhaven National Laboratory

Gauge-invariant charged, monopole and dyon fields in gauge theories

International Nuclear Information System (INIS)

Froehlich, J.; Marchetti, P.A.

1999-01-01

We propose explicit recipes to construct the Euclidean Green functions of gauge-invariant charged, monopole and dyon fields in four-dimensional gauge theories whose phase diagram contains phases with deconfined electric and/or magnetic charges. In theories with only either abelian electric or magnetic charges, our construction is an Euclidean version of Dirac's original proposal, the magnetic dual of his proposal, respectively. Rigorous mathematical control is achieved for a class of abelian lattice theories. In theories where electric and magnetic charges coexist, our construction of Green functions of electrically or magnetically charged fields involves taking an average over Mandelstam strings or the dual magnetic flux tubes, in accordance with Dirac's flux quantization condition. We apply our construction to 't Hooft-Polyakov monopoles and Julia-Zee dyons. Connections between our construction and the semiclassical approach are discussed

Capacitive gauging apparatus

International Nuclear Information System (INIS)

Walton, H.

1985-01-01

Apparatus for gauging physical dimensions of solid or tubular bodies (e.g. a nuclear fuel pellet) comprises a capacitive transducer having electrodes forming diametrically arranged pairs of capacitors and means for connecting the pairs, preferably sequentially, in an arm of a four arm electrical network. For circumferential scanning of a solid body along its length, the body is moved along a path of travel through head assembly including the transducer by means of plungers with the axis of the body being coincident with the axis of the transducer. As the body moves through the transducer the diametrically arranged pairs of capacitors scan the surface to result in a surface profile of the body. For scanning the bore of a pipe or tube the transducer is inserted as a probe and moved along the bore of the pipe or tube, means being provided for maintaining the probe coaxial with the pipe or tube. (author)

Triggering and measuring bent cosmic muon tracks with the Muon Spectrometer barrel for the first time

CERN Multimedia

Fabio Cerutti

During the ATLAS barrel toroid stability test, bent cosmic muon tracks were seen for the first time in the ATLAS cavern by means of the ATLAS muon spectrometer. The barrel toroid has been powered at its nominal current (20.5 thousand Amperes) and kept in steady state for more than one day during the weekend of 18-19 November (see a report on this test in the Magnet section). During this test one large sector and part of a small sector of the barrel muon spectrometer were readout and used to detect the cosmic muons tracks bent by the toroidal magnetic field. Thirteen muon stations in the feet sectors (sectors 13 and 14) have been used in this test. The muon stations are formed of Resistive Plate Chambers (RPC) that were providing the muon trigger, and Monitored Drift Tubes that were used to measure with high accuracy the muon curvature hence their momentum. The Level-1 Barrel trigger chain was based on the Barrel Middle Large chambers equipped with final production modules on both the on-detector and the o...

Beam-smiling in bent-Laue monochromators

International Nuclear Information System (INIS)

Ren, B.; Dilmanian, F.A.; Wu, X.Y.; Huang, X.; Ivanov, I.; Thomlinson, W.C.

1997-01-01

When a wide fan-shaped x-ray beam is diffracted by a bent crystal in the Laue geometry, the profile of the diffracted beam generally does not appear as a straight line, but as a line with its ends curved up or curved down. This effect, referred to as ' beam-smiling', has been a major obstacle in developing bent-Laue crystal monochromators for medical applications of synchrotron x-ray. We modeled a cylindrically bent crystal using the Finite Element Analysis (FEA) method, and we carried out experiments at the National Synchrotron Light Source and Cornell High Energy Synchrotron Source. Our studies show that, while beam-smiling exists in most of the crystal close-quote s area because of anticlastic bending effects, there is a region parallel to the bending axis of the crystal where the diffracted beam is ' smile-free'. By applying asymmetrical bending, this smile-free region can be shifted vertically away from the geometric center of the crystal, as desired. This leads to a novel method of compensating for beam-smiling. We will discuss the method of ' differential bending' for smile removal, beam-smiling in the Cauchios and the polychromatic geometry, and the implications of the method on developing single- and double-bent Laue monochromators. The experimental results will be discussed, concentrating on specific beam-smiling observation and removal as applied to the new monochromator of the Multiple Energy Computed Tomography [MECT] project of the Medical Department, Brookhaven National Laboratory. copyright 1997 American Institute of Physics

Internal ultrasonic testing of steam generator tubes

International Nuclear Information System (INIS)

Furlan, J.; Soleille, G.; Chalaye, H.

1983-01-01

The ''in situ'' inspection of steam generator tubes uses generally Foucault currents before starting and along its life. This inspection aims at searching cracks and corrosion defects. The Foucault current method is quite badly adapted to ''closed crack'' detection, for it doesn't introduce neither resistivity or magnetic permeability variation, or lack of matter. More, it is sensible to the magnetic properties of the tube itself and to its environment (tubular or support plates). It is why, this first systematic inspection has to be completed by an ultrasonic one allowing to bring new elements in the uncertain cases. A device with an internal probe has been developed. It ''lights'' the tube wall with the aid of a transducer of which beam reflects on a mirror. Operating conditions are the same as for Foucault current testing, that is to say the probe moves inside the tube without rotation of the device (bent parts are excluded) [fr

Personal computer as a part of radiometric gauges

International Nuclear Information System (INIS)

Machaj, B.

1992-01-01

Following the world tendency in the application of microcomputers in measuring instrumentation, standard personal computer, compatible with IBM PC/XT, was employed in the isotope gauges developed lately in the Institute. The are: beta backscatter coating thickness gauge, X-ray fluorescence multilayer coating thickness gauge with X-ray tube as radiation source, and automatic airborne dust pollution gauge. A simple interface containing: address decoder, programmable pulse counter, some buffers and latches was sufficient to connect the computer to the measuring head of the gauges. Thanks to the possibility of programming in higher level language (turbo Pascal), the gauges were developed in much shorter time than required for classical electronics. The experience gained during development of the gauges shows, that even in case of a simple instrument such as the beta backscatter coating thickness gauge, it is more economical to employ ready-made personal computer than to elaborate specific electronics for it, unless the gauge is produced in large numbers. The use of personal computer is particularly advantageous, when processing of the signal or control of the measuring cycle is more sophisticated, as in the case of the two other gauges. Block diagrams of the gauges and their interfaces are presented in the paper. In case of the airborne dust pollution gauge, flow chart of the computer program is also given. (author). 3 refs, 4 figs

Self-sensing concrete-filled FRP tubes using FBG strain sensors

Science.gov (United States)

Yan, Xin; Li, Hui

2007-07-01

Concrete-filled fiber-reinforced polymer (FRP) tube is a type of newly developed structural column. It behaves brittle failure at its peak strength, and so the health monitoring on the hoop strain of the FRP tube is essential for the life cycle safety of the structure. Herein, three types of FRP tubes including 5-ply tube, 2-ply tube with local reinforcement and FRP-steel composite tube were embedded with the optic fiber Bragg grating (FBG) strain sensors in the inter-ply of FRP or the interface between FRP and steel in the middle height and the hoop direction. The compressive behaviors of the concrete-filled FRP tubes were experimentally studied. The hoop strains of the FRP tubes were recorded in real time using the embedded FBG strain sensors as well as the embedded or surface electric resistance strain gauges. Results indicated that the FBG strain sensors can faithfully record the hoop strains of the FRP tubes in compression as compared with the embedded or surface electric resistance strain gauges, and the strains recorded can reach more than μɛ.

The relative cost of bent-hip bent-knee walking is reduced in water.

Science.gov (United States)

Kuliukas, Algis V; Milne, Nick; Fournier, Paul

2009-01-01

The debate about how early hominids walked may be characterised as two competing hypotheses: They moved with a fully upright (FU) gait, like modern humans, or with a bent-hip, bent-knee (BK) gait, like apes. Both have assumed that this bipedalism was almost exclusively on land, in trees or a combination of the two. Recent findings favoured the FU hypothesis by showing that the BK gait is 50-60% more energetically costly than a FU human gait on land. We confirm these findings but show that in water this cost differential is markedly reduced, especially in deeper water, at slower speeds and with greater knee flexion. These data suggest that the controversy about australopithecine locomotion may be eased if it is assumed that wading was a component of their locomotor repertoire and supports the idea that shallow water might have been an environment favourable to the evolution of early forms of "non-optimal" hominid bipedalism.

PIV Measurement of Pulsatile Flows in 3D Curved Tubes Using Refractive Index Matching Method

Energy Technology Data Exchange (ETDEWEB)

Hong, Hyeon Ji; Ji, Ho Seong; Kim, Kyung Chun [Pusan Nat’l Univ., Busan (Korea, Republic of)

2016-08-15

Three-dimensional models of stenosis blood vessels were prepared using a 3D printer. The models included a straight pipe with axisymmetric stenosis and a pipe that was bent 10° from the center of stenosis. A refractive index matching method was utilized to measure accurate velocity fields inside the 3D tubes. Three different pulsatile flows were generated and controlled by changing the rotational speed frequency of the peristaltic pump. Unsteady velocity fields were measured by a time-resolved particle image velocimetry method. Periodic shedding of vortices occurred and moves depended on the maximum velocity region. The sizes and the positions of the vortices and symmetry are influenced by mean Reynolds number and tube geometry. In the case of the bent pipe, a recirculation zone observed at the post-stenosis could explain the possibility of blood clot formation and blood clot adhesion in view of hemodynamics.

PIV Measurement of Pulsatile Flows in 3D Curved Tubes Using Refractive Index Matching Method

International Nuclear Information System (INIS)

Hong, Hyeon Ji; Ji, Ho Seong; Kim, Kyung Chun

2016-01-01

Three-dimensional models of stenosis blood vessels were prepared using a 3D printer. The models included a straight pipe with axisymmetric stenosis and a pipe that was bent 10° from the center of stenosis. A refractive index matching method was utilized to measure accurate velocity fields inside the 3D tubes. Three different pulsatile flows were generated and controlled by changing the rotational speed frequency of the peristaltic pump. Unsteady velocity fields were measured by a time-resolved particle image velocimetry method. Periodic shedding of vortices occurred and moves depended on the maximum velocity region. The sizes and the positions of the vortices and symmetry are influenced by mean Reynolds number and tube geometry. In the case of the bent pipe, a recirculation zone observed at the post-stenosis could explain the possibility of blood clot formation and blood clot adhesion in view of hemodynamics.

Clues from Bent Jets

Science.gov (United States)

Kohler, Susanna

2018-04-01

Powerful jets emitted from the centers of distant galaxies make for spectacular signposts in the radio sky. Can observations of these jets reveal information about the environments that surround them?Signposts in the SkyVLA FIRST images of seven bent double-lobed radio galaxies from the authors sample. [Adapted from Silverstein et al. 2018]An active supermassive black hole lurking in a galactic center can put on quite a show! These beasts fling out accreting material, often forming intense jets that punch their way out of their host galaxies. As the jets propagate, they expand into large lobes of radio emission that we can spot from Earth observable signs of the connection between distant supermassive black holes and the galaxies in which they live.These distinctive double-lobed radio galaxies (DLRGs) dont all look the same. In particular, though the jets are emitted from the black holes two poles, the lobes of DLRGs dont always extend perfectly in opposite directions; often, the jets become bent on larger scales, appearing to us to subtend angles of less than 180 degrees.Can we use our observations of DLRG shapes and distributions to learn about their surroundings? A new study led by Ezekiel Silverstein (University of Michigan) has addressed this question by exploring DLRGs living in dense galaxy-cluster environments.Projected density of DLRGcentral galaxy matches (black) compared to a control sample of random positionscentral galaxy matches (red) for different distances from acluster center. DLRGs have a higher likelihood of being located close to a cluster center. [Silverstein et al. 2018]Living Near the HubTo build a sample of DLRGs in dense environments, Silverstein and collaborators started from a large catalog of DLRGs in Sloan Digital Sky Survey quasars with radio lobes visible in Very Large Array data. They then cross-matched these against three galaxy catalogs to produce a sample of 44 DLRGs that are each paired to a nearby massive galaxy, galaxy group

Closed flux tubes and their string description in D=3+1 SU(N) gauge theories

Energy Technology Data Exchange (ETDEWEB)

Athenodorou, Andreas [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Bringoltz, Barak [Washington Univ., Seattle, WA (United States). Dept. of Physics; Teper, Michael [Oxford Univ. (United Kingdom). Centre for Theoretical Physics

2010-08-15

We calculate the energy spectrum of a confining flux tube that is closed around a spatial torus, as a function of its length l. We do so for various SU(N) gauge theories in 3+1 dimensions, and for various values of spin, parity and longitudinal momentum. We are able to present usefully accurate results for about 20 of the lightest such states, for a range of l that begins close to the (finite volume) deconfining phase transition at l{radical}{sigma} {proportional_to} 1.6, and extends up to l{radical}{sigma}{proportional_to}6 (where {sigma} is the string tension). We find that most of these low-lying states are well described by the spectrum of the Nambu-Goto free string theory in flat space-time. Remarkably, this is so not only at the larger values of l, where the gap between the ground state energy and the low-lying excitations becomes small compared to the mass gap, but also down to much shorter lengths where these excitation energies become large compared to {radical}{sigma}, the flux-tube no longer 'looks' anything like a thin string, and an expansion of the effective string action in powers of 1/l no longer converges. All this is for flux in the fundamental representation. We also calculate the k=2 (anti)symmetric ground states and these show larger corrections at small l. So far all this closely resembles our earlier findings in 2+1 dimensions. However, and in contrast to the situation in D=2+1, we also find that there are some states, with J{sup P}=0{sup -} quantum numbers, that show large deviations from the Nambu-Goto spectrum. We investigate the possibility that (some of) these states may encode the massive modes associated with the internal structure of the flux tube, and we discuss how the precocious free string behaviour of most states constrains the effective string action, on which much interesting theoretical progress has recently been made. (orig.)

Closed flux tubes and their string description in D=3 1 SU(N) gauge theories

International Nuclear Information System (INIS)

Athenodorou, Andreas; Bringoltz, Barak; Teper, Michael

2010-08-01

We calculate the energy spectrum of a confining flux tube that is closed around a spatial torus, as a function of its length l. We do so for various SU(N) gauge theories in 3+1 dimensions, and for various values of spin, parity and longitudinal momentum. We are able to present usefully accurate results for about 20 of the lightest such states, for a range of l that begins close to the (finite volume) deconfining phase transition at l√σ ∝ 1.6, and extends up to l√σ∝6 (where σ is the string tension). We find that most of these low-lying states are well described by the spectrum of the Nambu-Goto free string theory in flat space-time. Remarkably, this is so not only at the larger values of l, where the gap between the ground state energy and the low-lying excitations becomes small compared to the mass gap, but also down to much shorter lengths where these excitation energies become large compared to √σ, the flux-tube no longer 'looks' anything like a thin string, and an expansion of the effective string action in powers of 1/l no longer converges. All this is for flux in the fundamental representation. We also calculate the k=2 (anti)symmetric ground states and these show larger corrections at small l. So far all this closely resembles our earlier findings in 2+1 dimensions. However, and in contrast to the situation in D=2+1, we also find that there are some states, with J P =0 - quantum numbers, that show large deviations from the Nambu-Goto spectrum. We investigate the possibility that (some of) these states may encode the massive modes associated with the internal structure of the flux tube, and we discuss how the precocious free string behaviour of most states constrains the effective string action, on which much interesting theoretical progress has recently been made. (orig.)

Study of residual stresses and plastic strains in expanded thin tubes

International Nuclear Information System (INIS)

Hassine, T.; Inglebert, G.; Point, N.

1993-01-01

The measurement of residual stresses with X-rays or with extending gauges, on expanded tubes, implies a longitudinal cutting up. The cutting-up provokes an elastic relaxing of the stresses and this is particularly important for thin tubes. The initial stresses and the geometry influence the variation of the stresses along the tube. The determination of the relaxed stresses is possible in certain cases with extending gauges measurements, but this determination is difficult and expensive. In order to analytically correct these stresses, some assumptions are used and verified with a finite element model. (author). 3 refs., 5 figs

Confinement in dually transformed U(1) lattice gauge theory

International Nuclear Information System (INIS)

Zach, M.

1997-10-01

The aim of this work is a detailed investigation of the confinement mechanism in U(1) lattice gauge theory. In the first chapters we give a review on the definition of compact Abelian gauge theory on space-time lattices, the numerical calculation of physical observables for exploring confinement, and the interpretation of the results in terms of the dual superconductor picture, which is introduced at two levels of description. We work out that the electric field strength and the magnetic currents around a charge pair can be described very well by a classical effective model of Maxwell and London equations, if fluctuations of the occurring fluxoid string are considered. In order to obtain a deeper understanding of confinement in U(1), we extend the duality transformation of the path integral to the correlation functions which are used to calculate expectation values of fields and currents. This not only helps to interpret U(1) lattice gauge theory as a limit of the dual Higgs model, but also opens the possibility for efficient calculations of expectation values in the presence of static charges by simulating the dual model. Using this technique we are able to consider large flux tube lengths, low temperatures, and multiply charged systems without loss of numerical precision. The dual simulation is applied to flux tubes between static charges, to periodically closed flux tubes (torelons), and to doubly charged systems. We find that the behavior of flux tubes for large charge distances cannot be explained by the picture of a classical dual type-II superconductor; the observed roughening of the flux tube agrees very well with the prediction from the effective string description. We also analyze the different contributions to the total energy of the electromagnetic field. For torelons we calculate both the free energy and the total field energy, split the free energy into a string tension and a string fluctuation part, and apply lattice sum rules modified for finite

A SYNTHESIS METHOD OF BASIC TERNARY BENT-SQUARES BASED ON THE TRIAD SHIFT OPERATOR

Directory of Open Access Journals (Sweden)

O. N. Zhdanov

2017-01-01

Full Text Available Practical application of advanced algebraic constructions in modern communication systems based on MC-CDMA (Multi Code Code Division Multiple Access technology and in cryptography necessitates their further research. One of the most commonly used advanced algebraic construction is the binary bent-function having a uniform amplitude spectrum of the Walsh-Hadamard transform and, accordingly, having the maximal distance from the codewords of affine code. In addition to the binary bent-functions researchers are currently focuses on the development of synthesis methods of their many-valued analogues. In particular, one of the most effective methods for the synthesis of many-valued bent-functions is the method based on the Agievich bent-squares. In this paper, we developed a regular synthesis method of the ternary bent-squares on the basis of an arbitrary spectral vector and the regular operator of the triad shift. The classification of spectral vectors of lengths N = 3 and N = 9 is performed. On the basis of spectral classification more precise definition of many-valued bent-sequences is given, taking into account the existence of the phenomenon of many-valued bent-sequences for the length, determined by odd power of base. The paper results are valuable for practical use: the development of new constant amplitude codes for MC-CDMA technology, cryptographic primitives, data compression algorithms, signal structures, algorithms of block and stream encryption, based on advanced principles of many-valued logic. The developed bent-squares design method is also a basis for further theoretical research: development of methods of the permutation of rows and columns of basic bent-squares and their sign coding, synthesis of composite bent-squares. In addition, the data on the spectral classification of vectors give the task of constructing the synthesis methods of bent-functions of lengths N = 32k+1, k Є ℕ.

Magnetic monopoles and the dual London equation in SU(3) lattice gauge theory

International Nuclear Information System (INIS)

Skala, P.; Faber, M.; Zach, M.

1996-01-01

The dual superconductor model of confinement in non-Abelian gauge theories is studied in a gauge invariant formulation. We propose a method for the determination of magnetic monopole currents in non-Abelian gauge theories which does not need a projection to Abelian degrees of freedom. With this definition we are able to determine the distribution of magnetic currents and electric fields for the gluonic flux tube between a pair of static charges. Further we check the validity of the dual London equation in a gauge invariant formulation. (orig.)

Characterization of Friction Stir Welded Tubes by Means of Tube Bulge Test

International Nuclear Information System (INIS)

D'Urso, G.; Longo, M.; Giardini, C.

2011-01-01

Mechanical properties of friction stir welded joints are generally evaluated by means of conventional tensile test. This testing method might provide insufficient information because maximum strain obtained in tensile test before necking is small; moreover, the application of tensile test is limited when the joint path is not linear or even when the welds are executed on curved surfaces. Therefore, in some cases, it would be preferable to obtain the joints properties from other testing methods. Tube bulge test can be a valid solution for testing circumferential or longitudinal welds executed on tubular workpieces. The present work investigates the mechanical properties and the formability of friction stir welded tubes by means of tube bulge tests. The experimental campaign was performed on tubular specimens having a thickness of 3 mm and an external diameter of 40 mm, obtained starting from two semi-tubes longitudinally friction stir welded. The first step, regarding the fabrication of tubes, was performed combining a conventional forming process and friction stir welding. Sheets in Al-Mg-Si-Cu alloy AA6060 T6 were adopted for this purpose. Plates having a dimension of 225x60 mm were bent (with a bending axis parallel to the main dimension) in order to obtain semi-tubes. A particular care was devoted to the fabrication of forming devices (punch and die) in order to minimize the springback effects. Semi-tubes were then friction stir welded by means of a CNC machine tool. Some preliminary tests were carried out by varying the welding parameters, namely feed rate and rotational speed. A very simple tool having flat shoulder and cylindrical pin was used. The second step of the research was based on testing the welded tubes by means of tube bulge test. A specific equipment having axial actuators with a conical shape was adopted for this study. Some analyses were carried out on the tubes bulged up to a certain pressure level. In particular, the burst pressure and the

Further Results on Constructions of Generalized Bent Boolean Functions

Science.gov (United States)

2016-03-01

China; 2Naval Postgraduate School, Applied Mathematics Department, Monterey, CA 93943, USA; 3Science and Technology on Communication Security...in 1976 as an interesting combinatorial object with the important property of having op- timal nonlinearity [1]. Since bent functions have many...77–94 10 Zhao Y, Li H L. On bent functions with some symmet- ric properties. Discret Appl Math, 2006, 154: 2537– 2543

Study of channeling phenomena in bent crystals the new frontiers

CERN Document Server

Bolognini, Davide; Scandale, Walter; Vallazza, Erik

2008-01-01

More or less 30 years ago, it was experimentally demonstrated how a bent crystal can become a magnet: an object 1 mm thick, a couple of mm wide and a few cm high is, in fact, capable of steering particles as a dipole of several tens of Tesla. Exploiting this feature, from September 2006 the H8RD22 collaboration is testing several bent crystals in order to develop a crystal based collimation system for LHC: in very high energy accelerators, in fact, the typical multi-stage collimation system (that must be very efficient and must tolerate very high radiation) is expected not to allow to reach the nominal luminosity, limiting it to 40% of the desired value. A bent crystal could play a key role being a clever collimator: it is able to steer particles in a given direction with a high efficiency, thus increasing the cleaning efficiency, reducing the constraints on the alignment of the secondary collimator and finally increasing luminosity. But bent crystals are not only collimation: the radiation emitted by light p...

Effects of gauge volume on pseudo-strain induced in strain measurement using time-of-flight neutron diffraction

International Nuclear Information System (INIS)

Suzuki, Hiroshi; Harjo, Stefanus; Abe, Jun; Xu, Pingguang; Aizawa, Kazuya; Akita, Koichi

2013-01-01

Spurious or pseudo-strains observed in time-of-flight (TOF) neutron diffraction due to neutron attenuation, surface-effects and a strain distribution within the gauge volume were investigated. Experiments were carried out on annealed and bent ferritic steel bars to test these effects. The most representative position in the gauge volume corresponds to the neutron-weighted center of gravity (ncog), which takes into account variations in intensity within the gauge volume due to neutron attenuation and/or absence of material in the gauge volume. The average strain in the gauge volume was observed to be weighted towards the ncog position but following an increase in the size of the gauge volume the weighted average strain was changed because of the change in the ncog position when a strain gradient appeared within the gauge volume. On the other hand, typical pseudo-strains, which are well known, did appear in through-surface strain measurements when the gauge volume was incompletely filled by the sample. Tensile pseudo-strains due to the surface-effect increased near the sample surface and exhibited a similar trend regardless of the size of the gauge volume, while the pseudo-strains increased faster for the smaller gauge volume. Furthermore, a pseudo-strain due to a change in the ncog position was observed even when the gauge volume was perfectly filled in the sample, and it increased with an increase in the size of the gauge volume. These pseudo-strains measured were much larger than those simulated by the conventional modeling, whereas they were simulated by taking into account an incident neutron beam divergence additionally in the model. Therefore, the incident divergence of the incident neutron beam must be carefully designed to avoid pseudo-strains in time-of-flight neutron diffractometry

Bend-imitating theory and electron scattering in sharply-bent quantum nanowires

International Nuclear Information System (INIS)

Vakhnenko, O.O.

2011-01-01

The concept of bend-imitating description as applied to the one-electron quantum mechanics in sharply-bent ideal electron waveguides and its development into a self consistent theory are presented. In the framework of bend-imitating approach, the investigation of the electron scattering in a doubly-bent 2D quantum wire with S-like bend has been made, and the explicit dependences of the transmission and reflection coefficients on geometrical parameters of a structure, as well as on the electron energy, have been obtained. The total elimination of the mixing between the scattering channels of a S-like bent quantum wire is predicted.

Radioactive thickness gauge (1962)

International Nuclear Information System (INIS)

Guizerix, J.

1962-01-01

The author describes a thickness gauge in which the scintillating crystal detector alternately 'sees' a radioactive source through the material which is to be measured and then a control source of the same material; the radiations are separated in time by an absorbing valve whose sections are alternately full and hollow. The currents corresponding to the two sources are separated beyond the photomultiplier tube by a detector synchronized with the rotation of the valve. The quotient of these two currents is then obtained with a standard recording potentiometer. It is found that the average value of the response which is in the form G = f(I 1 /I 2 ) is not affected by decay of the radioactive sources, and that it is little influenced by variations of high tension, temperature, or properties of the air in the source detector interval. The performance of the gauge is given. (author) [fr

Precast, Prestressed Concrete Bent Caps : Volume 2, Design Recommendations and Design Examples

Science.gov (United States)

2018-04-01

Recommendations for design of pretensioned bent caps are developed based on the findings of full-scale experimental tests of bent cap subassemblages. Companion examples are provided to demonstrate implementation of the design recommendations. First, ...

Difficulty with cuff deflation of reinforced tracheal tube caused by inflation line occlusion with silk thread ligation and fixation.

Science.gov (United States)

Gotoh, Sayoko; Sugiyama, Daisuke; Imai, Eriko; Kawamata, Mikito

2015-03-05

A reinforced tracheal tube, ligated with silk threads, was inserted into a tracheostomy orifice and fixed to the skin. The cuff inflation line of the reinforced tracheal tube became occluded. Reinforced 'armoured' tracheal tubes have a spiral of wire embedded into the wall of the tube to give strength and flexibility, and may be sharply bent without compromising the tube lumen. The tracheal cuff attached to the tube is inflated by injecting air through a narrow-diameter tube welded to the outside of the tracheal tube. When a reinforced tracheal tube is ligated and fixed with silk threads, it should be confirmed whether the tracheal tube cuff can be deflated and inflated after fixation. Moreover, because occlusion can be eliminated by removing all silk threads used to ligate a tracheal tube, they should be removed before extubation. 2015 BMJ Publishing Group Ltd.

Handling the problem of the brine tubing bend on the basis of experiences gained during UGS - Mogilno construction

International Nuclear Information System (INIS)

Zola, P.; Skwarczynski, S.

2005-01-01

In the article problems of brine tubing bending and bent string cutting methods in the well conditions has been described. Implementation of safety joint in the brine string as an alternative solution that eliminates the need of cutting has been presented as well. (authors)

Twisted boundary conditions: a non-perturbative probe for pure non-abelian gauge theories

International Nuclear Information System (INIS)

Baal, P. van.

1984-01-01

In this thesis the author describes a pure non-abelian gauge theory on the hypertorus with gauge group SU(N). To test the flux tube picture he has studied the large distance limit of this theory, leading to a large coupling constant. To tackle this problem, he describes two approaches, in both of which twisted boundary conditions play an important role. (Auth.)

Dispersion in a bent-solenoid channel with symmetric focusing

Energy Technology Data Exchange (ETDEWEB)

Wang, Chun-xi [Argonne National Lab. (ANL), Argonne, IL (United States)

2001-08-21

Longitudinal ionization cooling of a muon beam is essential for muon colliders and will be useful for neutrino factories. Bent-solenoid channels with symmetric focusing has been considered for beam focusing and for generating the required dispersion in the ``emittance exchange'' scheme of longitudinal cooling. In this paper, we derive the Hamiltonian that governs the linear beam dynamics of a bent-solenoid channel, solve the single-particle dynamics, and give equations for determining the lattice functions, in particular, the dispersion functions.

Development of Evaluation Technology of the Integrity of HWR Pressure Tubes

International Nuclear Information System (INIS)

Kim, Y. S.; Jeong, Y. M.; Ahn, S. B.

2005-03-01

Major degradation of the feeder pipe is the thinning due to the flow accelerated corrosion and the cracking in the bent region due to the stress corrosion cracking. The feeder pipe in a PHWR is a pipe to supply the coolant to the pressure tube and the heated coolant to the steam generator for power generation. Approximately 380 pipes are installed on the inlet side and outlet side each with two bent regions in the 600 MW-class PHWR. After a leakage in the bent region of the feeder pipe, it is required to examine all the pipes in order to ensure the integrity of the pressure boundaries. It is not easy, however, to examine all the pipes with the conventional ultrasonic method, because of a high dose of radiation exposure and a limited accessibility to the pipe. In order to get rid of the limited accessibility, the ultrasonic guided wave method are developed for detection and evaluation of the cracks in the feeder pipe. The dispersion mode analysis was performed for the development of long-range guided wave inspection for the feeder pipe. An analytical approach for the straight pipe as well as numerical approach for the bent pipe with 2-D FFT were accomplished. A computer program for the calculation of the dispersion curves and wave structures was developed. Based on the dispersion curves and wave structure of the feeder pipe, candidates for the optimal parameters on the frequencies and vibration modes were selected. A time-frequency analysis methodology was developed for the mode identification of received ultrasonic signal. A high power tone-burst ultrasonic system has been setup for the generation of guided waves. Various artificial notches were fabricated on the bent feeder pipes for the experiment on the flaw detection. Considering the results of dispersion analysis and field condition, the torsional vibration mode, T(0,1) is selected for the first choice. An array of electromagnetic acoustic transducers (EMAT) was designed and fabricated for the generation of T

Development of Evaluation Technology of the Integrity of HWR Pressure Tubes

Energy Technology Data Exchange (ETDEWEB)

Kim, Y S; Jeong, Y M; Ahn, S B [and others

2005-03-15

Major degradation of the feeder pipe is the thinning due to the flow accelerated corrosion and the cracking in the bent region due to the stress corrosion cracking. The feeder pipe in a PHWR is a pipe to supply the coolant to the pressure tube and the heated coolant to the steam generator for power generation. Approximately 380 pipes are installed on the inlet side and outlet side each with two bent regions in the 600 MW-class PHWR. After a leakage in the bent region of the feeder pipe, it is required to examine all the pipes in order to ensure the integrity of the pressure boundaries. It is not easy, however, to examine all the pipes with the conventional ultrasonic method, because of a high dose of radiation exposure and a limited accessibility to the pipe. In order to get rid of the limited accessibility, the ultrasonic guided wave method are developed for detection and evaluation of the cracks in the feeder pipe. The dispersion mode analysis was performed for the development of long-range guided wave inspection for the feeder pipe. An analytical approach for the straight pipe as well as numerical approach for the bent pipe with 2-D FFT were accomplished. A computer program for the calculation of the dispersion curves and wave structures was developed. Based on the dispersion curves and wave structure of the feeder pipe, candidates for the optimal parameters on the frequencies and vibration modes were selected. A time-frequency analysis methodology was developed for the mode identification of received ultrasonic signal. A high power tone-burst ultrasonic system has been setup for the generation of guided waves. Various artificial notches were fabricated on the bent feeder pipes for the experiment on the flaw detection. Considering the results of dispersion analysis and field condition, the torsional vibration mode, T(0,1) is selected for the first choice. An array of electromagnetic acoustic transducers (EMAT) was designed and fabricated for the generation of T

Improvement of hydroforming processes using tailored semi-finished tubes

Energy Technology Data Exchange (ETDEWEB)

Goebel, R.; Chatti, S.; Homberg, W.; Kleiner, M.; Shankar, R. [Dortmund Univ. (Germany). Inst. of Forming Technology and Lightweight Construction

2005-07-01

The manufacturing of curved tubular workpieces with complex geometry by hydroforming is a well known process. The formability of workpieces is limited by the overall amount of expansion, which always has to start with the smallest perimeter. Especially workpieces with a high ratio between the smallest and widest diameter are critical with regard to their manufacture. To improve the capability the hydroforming process, a new concept using tailored semi-finished tubes with a variable cross-section has been developed. Instead of only expanding a tube with the smallest diameter, the diameter of a tube with middle-sized cross-section is reduced locally by a spinning process so that only the critical regions left have to be expanded. Due to the fact that usually the pre-form has to be bent to assure that it fits into the tool, an additional specialized tube-bending process has been developed to realize the bending of tubes with variable diameter. In this article, the investigation and optimization of this process chain is presented. The capabilities of the process have been improved regarding the behavior of the workpieces in the hydroforming process by manufacturing a complex structural part originating from automotive industry. (orig.)

Propagation of polarised light in bent hi-bi spun fibres

Energy Technology Data Exchange (ETDEWEB)

Przhiyalkovsky, Ya V; Morshnev, S K; Starostin, N I; Gubin, V P [V.A.Kotel' nikov Institute of Radio Engineering and Electronics, Russian Academy of Sciences, Fryazino branch, Fryazino, Moscow Region (Russian Federation)

2015-11-30

The evolution of polarisation states (PS's) of broadband light propagating through a bent optical fibre with a helical structure of its refractive index anisotropy (hi-bi spun fibre) has been studied theoretically and experimentally. It has been shown that there exists a coordinate system of PS's in which the differential Jones matrix can be replaced by a diagonal matrix, which allows the polarisation parameters of the output broadband light to be readily calculated with sufficient accuracy. We have derived a formula for evaluating the magneto-optical sensitivity of a bent spun fibre. An approach has been proposed for restoring the degree of polarisation of light in a bent hi-bi spun fibre and, as a consequence, the visibility (contrast) of the interferometer in a current sensor with a sensing element based on the fibre under consideration. (optical fibres)

Stress analysis of steam generator row-1 tubes

International Nuclear Information System (INIS)

Kim, Woo Gon; Ryu, Woo Seog; Lee, Ho Jin; Kim, Sung Chung

2000-01-01

Residual stresses induced in U-bending and tube-to-tubesheet joining processes of PWR's steam generator row-1 tube were measured by X-ray method and Hole-Drilling Method(HDM). The stresses resulting from the internal pressure and the temperature gradient in the steam generator were also estimated theoretically. In U-bent regions, the residual stresses at extrados were induced with compressive stress(-), and its maximum value reached -319 Mpa in axial direction at ψ=0 .deg. in position. Maximum tensile residual stress of 170 MPa was found to be at the flank side at position of ψ=90 deg., i.e., at apex region. In tube-to-tubesheet joining methods, the residual stresses induced by the explosive joint method were found to be lower than that by the mechanical roll method. The gradient of residual stress along the expanded tube was highest at the transition region, and the residual stress in circumferential direction was found to be higher than the residual stress in axial direction. Hoop stress due to an internal pressure between primary and secondary side was analyzed to be 76 MPa and thermal stress was 45 MPa

Behavior of micropiles in bridge bent applications.

Science.gov (United States)

2010-12-01

This project concerned the behavior of micropiles under lateral loads. The North Carolina Department of Transportation was specifically interested in the use of micropiles to support bridge bents. In this configuration micropiles would be subjected t...

Bent versus straight tips in micropulsed longitudinal phacoemulsification.

Science.gov (United States)

Stagg, Brian C; Gupta, Isha; Cahoon, Judd; Ronquillo, Cecinio; Shi, Dallas; Zaugg, Brian; Gardiner, Gareth; Barlow, William R; Pettey, Jeff H; Aabid Farukhi, M; Jensen, Jason; Olson, Randall J

2015-10-01

The aim of this study was to evaluate bent and straight phacoemulsification tips to determine which tip is more efficient in removal of lens fragments, using micropulsed longitudinal ultrasound in phacoemulsification. In vitro laboratory study. The John A. Moran Eye Center Laboratories, University of Utah, Salt Lake City, Utah, was the study setting. Pig lenses hardened in a manner comparable with dense human cataracts were cut into 2-mm cubes and removed with micropulsed longitudinal ultrasound using settings previously shown to be optimally efficient (6 milliseconds on and 6 milliseconds off for a bent tip). To verify this time as most efficient for a straight tip, we also tested times of 5, 6, and 7 milliseconds time on and off. The tips were either straight or with a 20-degree bend. Twenty cubes were used for each comparative run. For the straight tip, 6 milliseconds on (1.56 ± 0.815 seconds) was significantly more efficient than 7 milliseconds on (2.45 ± 1.56 seconds, p = 0.001) and not significantly more efficient than 5 milliseconds on (1.69 ± 0.86 seconds, p = 0.43). Five milliseconds off time (1.45 ± 0.76s) was more efficient than 6 milliseconds (2.06 ± 1.37 seconds, p = 0.004) and 7 milliseconds off (2.18 ± 1.24s, p = 0.001). The straight tip was more efficient than the bent tip (1.38 ± 0.83 versus 2.93 ± 2.14 seconds, p = 0.006). Results are contrary to accepted common belief. Micropulsed longitudinal phacoemulsification is more efficient with a straight rather than a bent tip. Copyright © 2015 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

Magnetic Monopoles and the Dual London Equation in SU(3) Lattice Gauge Theory

OpenAIRE

Skala, Peter; Faber, Manfried; Zach, Martin

1996-01-01

We propose a method for the determination of magnetic monopole currents in non-Abelian gauge theories which does not need a projection to Abelian degrees of freedom. With this definition we are able to determine the distribution of magnetic currents and electric fields for the gluonic flux tube between a pair of static charges. Further we check the validity of the Gauss law and the dual London equation in a gauge invariant formulation.

Flux tubes at finite temperature

Energy Technology Data Exchange (ETDEWEB)

Cea, Paolo [INFN, Sezione di Bari,Via G. Amendola 173, I-70126 Bari (Italy); Dipartimento di Fisica dell’Università di Bari,Via G. Amendola 173, I-70126 Bari (Italy); Cosmai, Leonardo [INFN, Sezione di Bari,Via G. Amendola 173, I-70126 Bari (Italy); Cuteri, Francesca; Papa, Alessandro [Dipartimento di Fisica, Università della Calabria & INFN-Cosenza,Ponte Bucci, cubo 31C, I-87036 Rende (Cosenza) (Italy)

2016-06-07

The chromoelectric field generated by a static quark-antiquark pair, with its peculiar tube-like shape, can be nicely described, at zero temperature, within the dual superconductor scenario for the QCD confining vacuum. In this work we investigate, by lattice Monte Carlo simulations of the SU(3) pure gauge theory, the fate of chromoelectric flux tubes across the deconfinement transition. We find that, if the distance between the static sources is kept fixed at about 0.76 fm ≃1.6/√σ and the temperature is increased towards and above the deconfinement temperature T{sub c}, the amplitude of the field inside the flux tube gets smaller, while the shape of the flux tube does not vary appreciably across deconfinement. This scenario with flux-tube “evaporation” above T{sub c} has no correspondence in ordinary (type-II) superconductivity, where instead the transition to the phase with normal conductivity is characterized by a divergent fattening of flux tubes as the transition temperature is approached from below. We present also some evidence about the existence of flux-tube structures in the magnetic sector of the theory in the deconfined phase.

Motion of channeling particles in a bent crystal

International Nuclear Information System (INIS)

Avakian, A.R.; Harutyunian, A.S.; Hovanessian, A.G.; Shahinian, S.M.; Yang, C.

1990-01-01

The motion of high-energy charged particles in a bent crystal is investigated in the approximation of the model of continuous potential of crystallographic planes and with account of incoherent scattering on the atoms of media. Angular distribution of charged particle beams is investigated at the exit of the bent region of the crystal in dependence with the maximum deflection angle and energy of particles. The dependence of the fraction of channeling particles on crystal thickness, crystal curvature and particle energy is found in a simple model approximation. The influence of crystal curvature on incoherent scattering of particles in the crystal is analyzed. The concept of an optimal thickness for the maximum number of particles deflected at a given angle is considered. 8 refs.; 8 figs

A simple trapping method of exhaled water using an ice-cooled tube to monitor the tritium level in human body

International Nuclear Information System (INIS)

Nogawa, Norio; Makide, Yoshihiro

1994-01-01

A convenient and efficient method is developed for the trapping of water in exhaled air. A bent-V-shaped glass sampling tube was immersed in iced water and exhaled air was introduced into the tube through a plastic straw. The trapping efficiency of exhaled water was equivalent to those with more complex and troublesome methods. Using anywhere available ice, the water in exhaled air can be rapidly collected with this method and the tritium level in the body will be quickly obtained. (author)

Cardiorespiratory and metabolic responses during straight and bent knee cycling.

Science.gov (United States)

Mandroukas, K; Angelopoulou, N; Christoulas, K; Vrabas, I S

2000-06-01

This study examined the influence of knee angle on the cardiorespiratory system loading during submaximal and maximal stationary cycle ergometry. Experimental design and participants: eighteen untrained women (age: 21+/-1.88 years, weight: 57+/-5.75 kg, height: 165+/-5.03 cm, values are mean+/-SD) volunteered as subjects and underwent two-cycle ergometer incremental (Jaeger ER900) tests: 1) straight knee (180 degrees), 2) bent knee (140 degrees). oxygen uptake (VO2), ventilation (VE) and respiratory exchange ratio (RER) were measured continuously during each test using an open circuit spirometry and blood lactate concentration was determined by means of an enzymatic method. Comparing cycling with "straight knee" to cycling with "bent knee" at 50 W, heart rate (HR), V(E) and VO2 were significantly higher (10.6%, 12.5%, 17.8%). At 100 W, blood lactate was significantly lower (10.8%) while VO2 and RER was higher (5.5%, 7.1%). During maximal exercise, the total exercise time was significantly longer (11.2%) and VE, VO2 and HR were significantly higher during cycling with "straight knee" compared to cycling with "bent knee". No significant difference in peak lactate was evident between the two sitting positions. The results of this study indicate that cycling with bent knee requires lower oxygen uptake while pedaling with straight knee is the only way to reach VO2max during cycle testing, since the cardiorespiratory system is fully taxed.

Instruments for non-destructive evaluation of advanced test reactor inpile tubes

International Nuclear Information System (INIS)

Livingston, R.A.; Beller, L.S.; Edgett, S.M.

1986-01-01

The Advanced Test Reactor is a 250 MW LWR used primarily for irradiation testing of materials contained in inpile tubes that pass through the reactor core. These tubes provided the high pressure and temperature water environment required for the test specimens. The reactor cooling water surrounding the inpile tubes is at much lower pressure and temperature. The structural integrity of the inpile tubes is monitored by routine surveillance to ensure against unplanned reactor shutdowns to replace defective inpile tubes. The improved instruments developed for inpile tube surveillance include a bore profilometer, ultrasonic flaw detetion system and bore diameter gauges. The design and function of these improved instruments is presented

Renormalizable Non-Covariant Gauges and Coulomb Gauge Limit

CERN Document Server

Baulieu, L

1999-01-01

To study ``physical'' gauges such as the Coulomb, light-cone, axial or temporal gauge, we consider ``interpolating'' gauges which interpolate linearly between a covariant gauge, such as the Feynman or Landau gauge, and a physical gauge. Lorentz breaking by the gauge-fixing term of interpolating gauges is controlled by extending the BRST method to include not only the local gauge group, but also the global Lorentz group. We enumerate the possible divergences of interpolating gauges, and show that they are renormalizable, and we show that the expectation value of physical observables is the same as in a covariant gauge. In the second part of the article we study the Coulomb-gauge as the singular limit of the Landau-Coulomb interpolating gauge. We find that unrenormalized and renormalized correlation functions are finite in this limit. We also find that there are finite two-loop diagrams of ``unphysical'' particles that are not present in formal canonical quantization in the Coulomb gauge. We verify that in the ...

Colour magnetic currents and the dual London equation in SU(3) lattice gauge theory

International Nuclear Information System (INIS)

Skala, P.; Faber, M.; Zach, M.

1997-01-01

We propose a method for the determination of magnetic currents in non-Abelian gauge theories which does not need a projection to Abelian degrees of freedom. With this definition we are able to determine the distribution of magnetic currents and electric fields for the gluonic flux tube between a pair of static charges. Further we check the validity of the Gauss law and the dual London equation in a gauge-invariant formulation. (orig.)

Bent silica nanosheets directed from crystalline templates controlled by proton donors

International Nuclear Information System (INIS)

Matsukizono, Hiroyuki; Jin, Ren-Hua

2011-01-01

Linear poly(ethyleneimine) (LPEI) is easily crystallizable with the formation of various morphologies in the aqueous medium when its hot solution cooled down to room temperature. Herein, we prepared a series of crystalline precipitates of LPEI grown in the presence of proton donating compounds such as Tris–HCl, tartaric acid, amino acids, and used the precipitates in directing silica deposition. Since the proton donating compounds can mediate the pH with donating the proton to LPEI, the crystallization of LPEI evidently depended on the concentrations of the proton donating compounds. It was found that the precipitates grown in the conditions of the pH ranged 8.2–8.5 directed well-controlled bent nanosheet of silica/LPEI composites. The bent nanosheet is constructed by multi-layered structures with a little slippage between layers. The bent nanosheet silica has slit-like pore with ca. 10 nm width.

Global gauge fixing in lattice gauge theories

Energy Technology Data Exchange (ETDEWEB)

Fachin, S.; Parrinello, C. (Physics Department, New York University, 4 Washington Place, New York, New York (USA))

1991-10-15

We propose a covariant, nonperturbative gauge-fixing procedure for lattice gauge theories that avoids the problem of Gribov copies. This is closely related to a recent proposal for a gauge fixing in the continuum that we review. The lattice gauge-fixed model allows both analytical and numerical investigations: on the analytical side, explicit nonperturbative calculations of gauge-dependent quantities can be easily performed in the framework of a generalized strong-coupling expansion, while on the numerical side a stochastic gauge-fixing algorithm is very naturally associated with the scheme. In both applications one can study the gauge dependence of the results, since the model actually provides a smooth'' family of gauge-fixing conditions.

High-Speed Measurement of the Internal Diameter of Tubes: A Comparison of Methods

DEFF Research Database (Denmark)

Gundtoft, Hans Erik; Agerup, C.C.; Nielsen, N.

1974-01-01

The authors have compared various methods of tube measurement and have made the striking conclusion that the continuous measurement of the internal diameter of precision tubes with an air gauge is often useless in practice. The methods selected for experiment were all contactless and so included...

Method of detecting leakage from sealing attached to pressure tube

International Nuclear Information System (INIS)

Tomomatsu, Ken-ichi; Hayashi, Ken-ichi.

1990-01-01

The present invention provides a detection method for measuring the amount of water leaked from sealings attached to the lower end of a pressure tube. That is, the lower end of the pressure tube is sealed only by a metal sealing. A capturing vessel is placed under the pressure tube for capturing the leaked water dropping from the lower end of the pressure tube and the weight of the leaked water is measured on every capturing vessels to determine the amount of the leaked water. The leakage detection method based on the weight measurement has higher accuracy compared with a conventional volume measuring method using a water level gauge as described below. For example, if the volume of the captured water is 10cc, an error of about 0.1cc is caused by the volume measuring method using the water level gauge, whereas if 10g (10cc) weight of water is measured by using an accurate balance, error is only about 10 -4 g (10 -4 cc). Accordingly, the method of the present invention can measure at an accuracy about 1000 times as high as the conventional method. (I.S.)

Self-propelled in-tube shuttle and control system for automated measurements of magnetic field alignment

International Nuclear Information System (INIS)

Boroski, W.N.; Nicol, T.H.; Pidcoe, S.V.

1990-03-01

A magnetic field alignment gauge is used to measure the field angle as a function of axial position in each of the magnets for the Superconducting Super Collider (SSC). Present measurements are made by manually pushing the through the magnet bore tube and stopping at intervals to record field measurements. Gauge location is controlled through graduation marks and alignment pins on the push rods. Field measurements are recorded on a logging multimeter with tape output. Described is a computerized control system being developed to replace the manual procedure for field alignment measurements. The automated system employs a pneumatic walking device to move the measurement gauge through the bore tube. Movement of the device, called the Self-Propelled In-Tube Shuttle (SPITS), is accomplished through an integral, gas driven, double-acting cylinder. The motion of the SPITS is transferred to the bore tube by means of a pair of controlled, retractable support feet. Control of the SPITS is accomplished through an RS-422 interface from an IBM-compatible computer to a series of solenoid-actuated air valves. Direction of SPITS travel is determined by the air-valve sequence, and is managed through the control software. Precise axial position of the gauge within the magnet is returned to the control system through an optically-encoded digital position transducer attached to the shuttle. Discussed is the performance of the transport device and control system during preliminary testing of the first prototype shuttle. 1 ref., 7 figs

Novel polymerizable bent-shaped monomeric molecules

Czech Academy of Sciences Publication Activity Database

Kozmik, V.; Kovářová, A.; Kuchař, M.; Svoboda, Jiří; Novotná, Vladimíra; Glogarová, Milada; Kroupa, Jan

2006-01-01

Roč. 33, č. 1 (2006), s. 41-56 ISSN 0267-8292 R&D Projects: GA ČR(CZ) GA202/05/0431; GA MŠk(CZ) OC D14.50 Institutional research plan: CEZ:AV0Z10100520 Keywords : mesogens * polymerizable * bent-shaped molecules * liquid crystals * ferroelectricity Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.417, year: 2006

Composite gauge bosons of transmuted gauge symmetry

International Nuclear Information System (INIS)

Terazawa, Hidezumi.

1987-10-01

It is shown that effective gauge theories of composite gauge bosons describing the dynamics of composite quarks and leptons can be transmuted from the subcolor gauge theory describing that of subquarks due to the condensation of subquarks and that the equality of effective gauge coupling constants can result as in a grand unified gauge theory. (author)

Design rules for out-of-plane stability of roller bent steel arches with FEM

NARCIS (Netherlands)

Spoorenberg, R.C.; Snijder, H.H.; Hoenderkamp, J.C.D.; Beg, D.

2012-01-01

This paper describes a numerical investigation into the out-of-plane buckling behavior of freestanding roller bent steel arches. As roller bent arches have structural imperfections which differ considerably from those of hot-rolled or welded sections, specific attention is paid to their inclusion in

Classifying bent radio galaxies from a mixture of point-like/extended images with Machine Learning.

Science.gov (United States)

Bastien, David; Oozeer, Nadeem; Somanah, Radhakrishna

2017-05-01

The hypothesis that bent radio sources are supposed to be found in rich, massive galaxy clusters and the avalibility of huge amount of data from radio surveys have fueled our motivation to use Machine Learning (ML) to identify bent radio sources and as such use them as tracers for galaxy clusters. The shapelet analysis allowed us to decompose radio images into 256 features that could be fed into the ML algorithm. Additionally, ideas from the field of neuro-psychology helped us to consider training the machine to identify bent galaxies at different orientations. From our analysis, we found that the Random Forest algorithm was the most effective with an accuracy rate of 92% for a classification of point and extended sources as well as an accuracy of 80% for bent and unbent classification.

Liquid Oscillations in a U-Tube

Science.gov (United States)

Aguilar, Horacio Munguía; Maldonado, Rigoberto Franco; Navarro, Luis Barba

2018-01-01

In hydrostatics, pressure measurement with U-gauges and their relationship to density is a well-known experiment. Very little is studied or experimented with the dynamics of the movement of a liquid in a U-tube probably due to its theoretical complexity but, after all, it is a simple damped oscillating system. In this paper we present a relatively…

Lattice gauge theory approach to quantum chromodynamics

International Nuclear Information System (INIS)

Kogut, J.B.

1983-01-01

The author reviews in a pedagogical fashion some of the recent developments in lattice quantum chromodynamics. This review emphasizes explicit examples and illustrations rather than general proofs and analyses. It begins with a discussion of the heavy-quark potential in continuum quantum chromodynamics. Asymptotic freedom and renormalization-group improved perturbation theory are discussed. A simple dielectric model of confinement is considered as an intuitive guide to the vacuum of non-Abelian gauge theories. Next, the Euclidean form of lattice gauge theory is introduced, and an assortment of calculational methods are reviewed. These include high-temperature expansions, duality, Monte Carlo computer simulations, and weak coupling expansions. A #betta#-parameter calculation for asymptotically free-spin models is presented. The Hamiltonian formulation of lattice gauge theory is presented and is illustrated in the context of flux tube dynamics. Roughening transitions, Casimir forces, and the restoration of rotational symmetry are discussed. Mechanisms of confinement in lattice theories are illustrated in the two-dimensional electrodynamics of the planar model and the U(1) gauge theory in four dimensions. Generalized actions for SU(2) gauge theories and the relevance of monopoles and strings to crossover phenomena are considered. A brief discussion of the continuity of fields and topologial charge in asymptotically free lattice models is presented. The final major topic of this review concerns lattice fermions. The species doubling problem and its relation to chiral symmetry are illustrated. Staggered Euclidean fermion methods are discussed in detail, with an emphasis on species counting, remnants of chiral symmetry, Block spin variables, and the axial anomaly. Numerical methods for including fermions in computer simulations are considered. Jacobi and Gauss-Siedel inversion methods to obtain the fermion propagator in a background gauge field are reviewed

A new gauge for supersymmetric abelian gauge theories

International Nuclear Information System (INIS)

Smith, A.W.; Barcelos Neto, J.

1984-01-01

A new gauge for supersymmetric abelian gauge theories is presented. It is shown that this new gauge allows us to obtain terms which usually come as radiative corrections to the supersymmetric abelian gauge theories when one uses the Wess-Zumino gauge. (Author) [pt

Bent crystal X-ray optics for the diagnosis and applications of laser-produced plasmas

International Nuclear Information System (INIS)

Loetzsch, Robert

2012-01-01

The present thesis discussed several aspects of X-ray optics based on bent crystals and a number of applications of these optics. First, a deeper insight into the reflection properties of elastically bent perfect crystal optics was gained by the consideration of all deformation effects. It was shown that the reflection properties depend on the lateral position on the crystal, an effect that was not addressed before, neither experimentally nor theoretically. To investigate this effect, an apparatus for the measurement of Bragg angles of bent crystals with high angular resolution was built. It was measured that the lattice plane distances of two-dimensionally bent crystals vary laterally by up to 10 -4 . This effect has to be considered in high resolution X-ray spectroscopy and imaging with these bent crystals. It can explain discrepancies in theoretical and experimental spectrometer resolution with spherically bent crystals. Besides these principal investigations, in this thesis a number of X-ray optics were presented that demonstrate the application potential of bent crystal optics. This includes two optics that are used in the field of applications of laser-produced plasmas as high repeating hard X-ray sources. It was shown that an X-ray spectrometer based on full cylinder rings of highly oriented pyrolytic graphite is capable to record the rather weak single shot pulses from a high repeating 1 er-plasma X-ray source. This is possible due to the high collection efficiency of the instrument of up to 5.10 -4 . Furthermore, X-ray optics based on toroidally bent crystals that make it possible to spectrally select a bandwidth of ∝1 eV and focus the ultrashort X-ray pulses from such a laser-plasma source, were designed, prepared and characterized. It was shown that these bent crystals provide the calculated integrated reflectivity, the predicted bandwidth and focus to spot sizes smaller than 60 μm. A novel application of toroidally bent crystals was pointed out: a

Continuum gauge fields from lattice gauge fields

International Nuclear Information System (INIS)

Goeckeler, M.; Kronfeld, A.S.; Schierholz, G.; Wiese, U.J.

1993-01-01

On the lattice some of the salient features of pure gauge theories and of gauge theories with fermions in complex representations of the gauge group seem to be lost. These features can be recovered by considering part of the theory in the continuum. The prerequisite for that is the construction of continuum gauge fields from lattice gauge fields. Such a construction, which is gauge covariant and complies with geometrical constructions of the topological charge on the lattice, is given in this paper. The procedure is explicitly carried out in the U(1) theory in two dimensions, where it leads to simple results. (orig.)

Low cycle fatigue behavior of hot-bent 347 stainless steel in a simulated PWR water environment

Energy Technology Data Exchange (ETDEWEB)

Lee, Jun Ho; Seo, Myung Gyu; Jang, Chang Heui [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Hong, Jong Tae [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Tae Soon [Central Research InstituteKorea Hydro and Nuclear Power Co., Ltd., Daejeon (Korea, Republic of)

2016-11-15

The effect of hot bending on the Low cycle fatigue (LCF) behavior of 347 SS was evaluated in Room temperature (RT) air and simulated Pressurized water reactor (PWR) water environments. The LCF life of 347 SS in PWR water was shorter than that in RT air for the as-received and hot-bent conditions. The LCF life of hot-bent 347 SS was relatively longer than that of the as-received condition in both RT air and PWR water. Microstructure analysis indicated development of dislocation structure near niobium carbide particles and increase in dislocation density for the hot-bent 347 SS. Such microstructure acted as barriers to dislocation movement during the LCF test, resulting in minimal hardening for the hot-bent 347 SS in RT air.

Bent and branched chains of nanoresonators

Science.gov (United States)

Melikhova, A. S.; Popov, I. Yu

2014-10-01

We study the spectral problem for bent and branched chains of weakly coupled conglobate resonators. At the joint points the δ-coupling is assumed. Our approach is based on the theory of self-adjoint extensions of symmetric operators and transfer matrix method. The structure of the spectrum is described. For the both cases it is proved that the Hamiltonian has negative eigenvalue for some values of the model parameters.

PROFIL-360 high resolution steam generator tube profilometry system

International Nuclear Information System (INIS)

Glass, S.W.

1985-01-01

A high-resolution profilometry system, PROFIL 360, has been developed to assess the condition of steam generator tubes and rapidly produce the data to evaluate the potential for developing in-service leaks. The probe has an electromechanical sensor in a rotating head. This technique has been demonstrated in the field, saving tubes that would have been plugged with the go-gauge criterion and indicating plugging other high-risk candidates that might otherwise not have been removed from service

Profil-360 high resolution steam generator tube profilometry system

International Nuclear Information System (INIS)

Glass, S.W.

1985-01-01

A high-resolution profilometry system, PROFIL 360, has been developed to assess the condition of steam generator tubes and rapidly produce the data to evaluate the potential for developing in-service leaks. The probe has an electromechanical sensor in a rotating head. This technique has been demonstrated in the field, saving tubes that would have been plugged with the go-gauge criterion and indicating plugging other high-risk candidates that might otherwise not have been removed from service

Photoelastic investigation of the stresses in mitred bent-cylinders under bending, 2

International Nuclear Information System (INIS)

Sawa, Yoshiaki

1984-01-01

The states of stress distribution in mitred bend subjected to inplane uniform bending moment have been studied systematically by means of photoelastic stress freezing method. The relations between the stress concentration factor of fiber stress σsub(l) and of hoop stress σsub(theta) near the bent part and the angle of mitred bend are thoroughly investigated. The effects of fillet radius of the bent-part and wall thickness on the stress concentration factors are also discussed. (author)

Equipment for inspection and carrying out repairs, if required, for tube bundles of steam raising units

International Nuclear Information System (INIS)

Gugel, G.

1976-01-01

The equipment solves the problem of being able to inspect and possibly to repair U-tubes of a vertical steam raising unit standing on a tube floor, without draining the primary medium and bringing the test equipment and tools into the inside of the boiler first. This is achieved by leaving a considerable part of the equipment permanently in the hemispherical space under the tube floor and operating it from the outside, on the other side of the concrete shielding. An inspection tube is threaded in turn horizontally through a concrete shield, a tube duct in the heat insulation of the steam raising unit, and through a hole in the hemispherical space under the tube floor into this space. The end of an angle tube can be moved axially from outside the concrete shield and can be rotated in a semicircle above the tube axis. By interposing a, for example, 12 part distributor with 12 short, differently bent tubes 12 adjacent tubes opening into the tube floor can be controlled and tested, by axial movement of the angle tube together with the distributor, e.g. 4 x 12 other U tubes. A turbulent flow sensor, for example, can be introduced through the angle tube and distributor. In the non-operational condition the equipment is moved into a recess via a supporting angle and stopped there. (ORU) [de

Measurement of water content in semi-humid sandy land by using IAE-II neutron moisture gauge

International Nuclear Information System (INIS)

Feng Qi

1994-01-01

The feasibility of using a neutron moisture gauge to study moisture change in semi-humid sandy land was affirmed. The gauge is compact and can rapidly take measurements with small errors. It is found that both the inter-substance boundary surface and the space formed in fixing the neutron tube affect obviously the precision of measurements in the survey process. The calibration variance is the most important part of total uncertainty in measurements

New concept of the buildup factor in bent ducts

International Nuclear Information System (INIS)

Faik Ouahab, Z.; Jehouani, A.; Groetz, J.-E.

2011-01-01

A major problem confronting the radiation shielding designer is the accurate determination of neutron streaming through various penetrations in walls, ducts and mazes. The previous studies on neutron transmission were performed through empty ducts. The aim of this work is to evaluate the neutron transmission probability through a filled bent duct and the proposition of a new concept of the buildup factor for neutrons in multilegged ducts. An angular biaising technique is used in the Monte Carlo simulations to accelerate the calculation convergence. Results are first compared with those obtained by the MCNPX code. For an empty bent duct, the neutron transmission is only due to the neutron reflection on the duct wall. For a filled duct, the major contribution is due to the scattering on the atoms filling the duct.

Trafiksikkerhedseffekten af variable hastighedstavler i åbent land

DEFF Research Database (Denmark)

Larsen, Mette Kathrine; Andersen, Camilla Sloth

2017-01-01

I trafiksikkerhedsarbejdet er effektstudier væsentlige. Effektstudierne udarbejdes, således at andre vejmyndigheder kan se, hvilke effekter et givent tiltag kan have. I dette studie er der udarbejdet et effektstudie over variable hastighedstavler i åbent land, og yderligere er det undersøgt...

SU(N) gauge theories in 2+1 dimensions: glueball spectra and k-string tensions

Energy Technology Data Exchange (ETDEWEB)

Athenodorou, Andreas [Department of Physics, University of Cyprus,POB 20537, 1678 Nicosia (Cyprus); Computation-based Science and Technology Research Center, The Cyprus Institute,20 Kavafi Str., Nicosia 2121 (Cyprus); Teper, Michael [Rudolf Peierls Centre for Theoretical Physics, University of Oxford,1 Keble Road, Oxford OX1 3NP (United Kingdom)

2017-02-03

We calculate the low-lying glueball spectrum and various string tensions in SU(N) lattice gauge theories in 2+1 dimensions, and extrapolate the results to the continuum limit. We do so for for the range N∈[2,16] so as to control the N-dependence with a useful precision. We observe a number of striking near-degeneracies in the various J{sup PC} sectors of the glueball spectrum, in particular between C=+ and C=− states. We calculate the string tensions of flux tubes in a number of representations, and provide evidence that the leading correction to the N-dependence of the k-string tensions is ∝1/N rather than ∝1/N{sup 2}, and that the dominant binding of k fundamental flux tubes into a k-string is via pairwise interactions. We comment on the possible implications of our results for the dynamics of these gauge theories.

Steering of sub-GeV electrons by ultrashort Si and Ge bent crystals

Energy Technology Data Exchange (ETDEWEB)

Sytov, A.I. [Ferrara Univ. (Italy). Dipt. di Fisica e Scienze della Terra; Belarusian State Univ., Minsk (Belarus). Inst. for Nuclear Problems; INFN Sezione di Ferrara (Italy); Bandiera, L.; Mazzolari, A.; Bagli, E.; Germogli, G.; Guidi, V.; Romagnoni, M. [Ferrara Univ. (Italy). Dipt. di Fisica e Scienze della Terra; INFN Sezione di Ferrara (Italy); De Salvador, D.; Carturan, S.; Maggioni, G. [INFN, Laboratori Nazionali di Legnaro (Italy); Padova Univ. (Italy). Dipt. di Fisica; Berra, A.; Prest, M. [Univ. dell' Insubria, Como (Italy); INFN, Sezione di Milano Bicocca, Milan (Italy); Durighello, C. [Ferrara Univ. (Italy). Dipt. di Fisica e Scienze della Terra; INFN, Laboratori Nazionali di Legnaro (Italy); Padova Univ. (Italy). Dipt. di Fisica; INFN Sezione di Ferrara (Italy); Klag, P.; Lauth, W. [Mainz Univ. (Germany). Inst. fuer Kernphysik; Tikhomirov, V.V. [Belarusian State Univ., Minsk (Belarus). Inst. for Nuclear Problems; Vallazza, E. [INFN, Sezione di Trieste (Italy)

2017-12-15

We report the observation of the steering of 855 MeV electrons by bent silicon and germanium crystals at the MAinzer MIkrotron. Crystals with 15 μm of length, bent along (111) planes, were exploited to investigate orientational coherent effects. By using a piezo-actuated mechanical holder, which allowed to remotely change the crystal curvature, it was possible to study the steering capability of planar channeling and volume reflection vs. the curvature radius and the atomic number, Z. For silicon, the channeling efficiency exceeds 35%, a record for negatively charged particles. This was possible due to the realization of a crystal with a thickness of the order of the dechanneling length. On the other hand, for germanium the efficiency is slightly below 10% due to the stronger contribution of multiple scattering for a higher-Z material. Nevertheless this is the first evidence of negative beam steering by planar channeling in a Ge crystal. Having determined for the first time the dechanneling length, one may design a Ge crystal based on such knowledge providing nearly the same channeling efficiency of silicon. The presented results are relevant for crystal-based beam manipulation as well as for the generation of e.m. radiation in bent and periodically bent crystals. (orig.)

Steering of Sub-GeV electrons by ultrashort Si and Ge bent crystals

Science.gov (United States)

Sytov, A. I.; Bandiera, L.; De Salvador, D.; Mazzolari, A.; Bagli, E.; Berra, A.; Carturan, S.; Durighello, C.; Germogli, G.; Guidi, V.; Klag, P.; Lauth, W.; Maggioni, G.; Prest, M.; Romagnoni, M.; Tikhomirov, V. V.; Vallazza, E.

2017-12-01

We report the observation of the steering of 855 MeV electrons by bent silicon and germanium crystals at the MAinzer MIkrotron. Crystals with 15 μ m of length, bent along (111) planes, were exploited to investigate orientational coherent effects. By using a piezo-actuated mechanical holder, which allowed to remotely change the crystal curvature, it was possible to study the steering capability of planar channeling and volume reflection vs. the curvature radius and the atomic number, Z. For silicon, the channeling efficiency exceeds 35%, a record for negatively charged particles. This was possible due to the realization of a crystal with a thickness of the order of the dechanneling length. On the other hand, for germanium the efficiency is slightly below 10% due to the stronger contribution of multiple scattering for a higher-Z material. Nevertheless this is the first evidence of negative beam steering by planar channeling in a Ge crystal. Having determined for the first time the dechanneling length, one may design a Ge crystal based on such knowledge providing nearly the same channeling efficiency of silicon. The presented results are relevant for crystal-based beam manipulation as well as for the generation of e.m. radiation in bent and periodically bent crystals.

Derivation of the gauge link in light cone gauge

International Nuclear Information System (INIS)

Gao Jianhua

2010-01-01

In light cone gauge, a gauge link at light cone infinity is necessary for transverse momentum-dependent parton distribution to restore the gauge invariance in some specific boundary conditions. We derive such transverse gauge link in a more regular and general method. We find the gauge link at light cone infinity naturally arises from the contribution of the pinched poles: one is from the quark propagator and the other is hidden in the gauge vector field in light cone gauge. Actually, in the amplitude level, we have obtained a more general gauge link over the hypersurface at light cone infinity which is beyond the transverse direction. The difference of such gauge link between semi-inclusive deep inelastic scattering and Drell-Yan processes can also be obtained directly and clearly in our derivation.

Technology transfer: taking science from the books to the ground at Bent Creek Experimental Forest

Science.gov (United States)

Julia Kirschman

2014-01-01

Technology transfer has been an important part of the research program at Bent Creek Experimental Forest (Bent Creek) since its establishment in 1925. Our stated mission is to develop and disseminate knowledge and strategies for restoring, managing, sustaining, and enhancing the vegetation and wildlife of upland hardwood-dominated forest ecosystems of the Southern...

Vacuum structure of pure gauge theories on the lattice

International Nuclear Information System (INIS)

Haymaker, R.W.; Singh, V.; Browne, D.; Wosiek, J.; Max-Planck-Institut fuer Physik und Astrophysik, Muenchen

1992-01-01

Results from simulations on two aspects of quark confinement in the pure gauge sector are presented. First is the calculation of the profile of the flux tube connecting a static q bar q pair in SU(2). By use of the Michael sum rules as a constraint, evidence is set forth that the energy density at the center of the flux tube goes to a constant as a function of quark- separation. Slow variation of the width and energy density is not ruled out. Secondly in the confined phase of lattice U(l), the curl of the magnetic monopole current is calculated, and it is shown that the dual London equation is satisfied and that the electric fluxoid is quantized

Computation of hybrid static potentials in SU(3 lattice gauge theory

Directory of Open Access Journals (Sweden)

Reisinger Christian

2018-01-01

Full Text Available We compute hybrid static potentials in SU(3 lattice gauge theory. We present a method to automatically generate a large set of suitable creation operators with defined quantum numbers from elementary building blocks. We show preliminary results for several channels and discuss, which structures of the gluonic flux tube seem to be realized by the ground states in these channels.

Outcomes of torsional microcoaxial phacoemulsification performed by 12-degree and 22-degree bent tips.

Science.gov (United States)

Helvacioglu, Firat; Yeter, Celal; Tunc, Zeki; Sencan, Sadik

2013-08-01

To compare the safety and efficacy of Ozil Intelligent Phaco torsional microcoaxial phacoemulsification surgeries performed with 12-degree and 22-degree bent tips using the Infiniti Vision System. Maltepe University School of Medicine Department of Ophthalmology, Istanbul, Turkey. Comparative case series. Eyes were assigned to 2.2 mm microcoaxial phacoemulsification using the torsional mode with a 22-degree bent tip (Group 1) or a 12-degree bent tip (Group 2). The primary outcome measures were ultrasound time (UST), cumulative dissipated energy (CDE), longitudinal and torsional ultrasound (US) amplitudes, mean surgical time, mean volume of balanced salt solution used, and surgical complications. Both groups included 45 eyes. The mean UST, CDE, longitudinal US amplitude, and torsional US amplitude were 65 seconds ± 27.23 (SD), 11.53 ± 6.99, 0.22 ± 0.26, and 42.86 ± 15.64, respectively, in Group 1 and 84 ± 45.04 seconds, 16.68 ± 10.66, 0.48 ± 0.68, and 46.27 ± 14.74, respectively, in Group 2. The mean UST, CDE, and longitudinal amplitudes were significantly lower in Group 1 (P=.003, P=.008, and P=.022, respectively). The mean volume of balanced salt solution was 73.33 ± 28.58 cc in Group 1 and 82.08 ± 26.21 cc in Group 2 (P=.134). Torsional phacoemulsification performed with 22-degree bent tips provided more effective lens removal than 12-degree bent tips, with a lower UST and CDE. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Covalent Attachment of Bent-Core Mesogens to Silicon Surfaces

NARCIS (Netherlands)

Scheres, L.; Achten, R.; Giesbers, M.; Smet, de L.; Arafat, A.; Sudhölter, E.J.R.; Marcelis, A.T.M.; Zuilhof, H.

2009-01-01

Two vinyl-terminated bent core-shaped liquid crystalline molecules that exhibit thermotropic antiferroelectric SmCPA phases have been covalently attached onto a hydrogen-terminated silicon(111) surface. The surface attachment was achieved via a mild procedure from a mesitylene solution, using

CO2 laser ablation of bent optical fibers for sensing applications

International Nuclear Information System (INIS)

Lévesque, L; Jdanov, V

2011-01-01

A procedure for the fabrication of a fiber optic sensor involving CO 2 laser ablation at λ = 10.6 µm is proposed. A basic system to achieve optical fiber bending and material processing on a single mode optical fiber is described and it is demonstrated that an optical fiber can be bent at a very precise angle by focusing a CO 2 beam locally near the glass cladding surface until it reaches melting temperature. A method is also described for removing material at the apex of a bent fiber to obtain a smooth and well flattened plane surface that is suitable for optical fiber sensing

Measurement and models of bent KAP(001) crystal integrated reflectivity and resolution (invited)

Energy Technology Data Exchange (ETDEWEB)

Loisel, G. P., E-mail: gploise@sandia.gov; Wu, M.; Lake, P.; Dunham, G. S.; Bailey, J. E.; Rochau, G. A. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Stolte, W. [National Security Technologies, LLC, Livermore, California 94551 (United States); Kruschwitz, C. [National Security Technologies, LLC, Los Alamos, New Mexico 87544 (United States)

2016-11-15

The Advanced Light Source beamline-9.3.1 x-rays are used to calibrate the rocking curve of bent potassium acid phthalate (KAP) crystals in the 2.3-4.5 keV photon-energy range. Crystals are bent on a cylindrically convex substrate with a radius of curvature ranging from 2 to 9 in. and also including the flat case to observe the effect of bending on the KAP spectrometric properties. As the bending radius increases, the crystal reflectivity converges to the mosaic crystal response. The X-ray Oriented Programs (XOP) multi-lamellar model of bent crystals is used to model the rocking curve of these crystals and the calibration data confirm that a single model is adequate to reproduce simultaneously all measured integrated reflectivities and rocking-curve FWHM for multiple radii of curvature in both 1st and 2nd order of diffraction.

Evaluation of bent-crystal x-ray backlighting and microscopy techniques for the Sandia Z machine.

Science.gov (United States)

Sinars, Daniel B; Bennett, Guy R; Wenger, David F; Cuneo, Michael E; Porter, John L

2003-07-01

X-ray backlighting and microscopy systems for the 1-10-keV range based on spherically or toroidally bent crystals are discussed. These systems are ideal for use on the Sandia Z machine, a megajoule-class x-ray facility. Near-normal-incidence crystal microscopy systems have been shown to be more efficient than pinhole cameras with the same spatial resolution and magnification [Appl. Opt. 37, 1784 (1998)]. We show that high-resolution (< or = 10 microm) x-ray backlighting systems using bent crystals can be more efficient than analogous point-projection imaging systems. Examples of bent-crystal-backlighting results that demonstrate 10-microm resolution over a 20-mm field of view are presented.

Evaluation of bent-crystal x-ray backlighting and microscopy techniques for the Sandia Z machine

International Nuclear Information System (INIS)

Sinars, Daniel B.; Wenger, David F.; Cuneo, Michael E.; Porter, John L.; Bennett, Guy R.

2003-01-01

X-ray backlighting and microscopy systems for the 1-10-keV range based on spherically or toroidally bent crystals are discussed. These systems are ideal for use on the Sandia Z machine, a megajoule-class x-ray facility. Near-normal-incidence crystal microscopy systems have been shown to be more efficient than pinhole cameras with the same spatial resolution and magnification [Appl. Opt. 37, 1784 (1998)]. We show that high-resolution (≤10 μm) x-ray backlighting systems using bent crystals can be more efficient than analogous point-projection imaging systems. Examples of bent-crystal-backlighting results that demonstrate 10-μm resolution over a 20-mm field of view are presented

Flux Tube Dynamics in the Dual Superconductor

International Nuclear Information System (INIS)

Lampert, M.; Svetitsky, B.

1999-01-01

We have studied plasma oscillations in a flux tube created in a dual superconductor. The theory contains an Abelian gauge field coupled magnetically to a Higgs field that confines electric charge via the dual Meissner effect. Starting from a static flux tube configuration, with electric charges at either end, we release a fluid of electric charges in the system that accelerate and screen the electric field. The weakening of the electric field allows the flux tube to collapse, and the inertia of the charges forces it open again. We investigate both Type I and Type II superconductors, with plasma frequencies both above and below the threshold for radiation into the Higgs vacuum. (The parameters appropriate to QCD are in the Type II regime; the plasma frequency depends on the mass taken for the fluid constituents.) The coupling of the plasma oscillations to the Higgs field making up the flux tube is the main new feature in our work

A bent Laue-Laue monochromator for a synchrotron-based computed tomography system

CERN Document Server

Ren, B; Chapman, L D; Ivanov, I; Wu, X Y; Zhong, Z; Huang, X

1999-01-01

We designed and tested a two-crystal bent Laue-Laue monochromator for wide, fan-shaped synchrotron X-ray beams for the program multiple energy computed tomography (MECT) at the National Synchrotron Light Source (NSLS). MECT employs monochromatic X-ray beams from the NSLS's X17B superconducting wiggler beamline for computed tomography (CT) with an improved image quality. MECT uses a fixed horizontal fan-shaped beam with the subject's apparatus rotating around a vertical axis. The new monochromator uses two Czochralski-grown Si crystals, 0.7 and 1.4 mm thick, respectively, and with thick ribs on their upper and lower ends. The crystals are bent cylindrically, with the axis of the cylinder parallel to the fan beam, using 4-rod benders with two fixed rods and two movable ones. The bent-crystal feature of the monochromator resolved the difficulties we had had with the flat Laue-Laue design previously used in MECT, which included (a) inadequate beam intensity, (b) excessive fluctuations in beam intensity, and (c) i...

Flux tubes in U(1) - Do they attract or repel each other?

International Nuclear Information System (INIS)

Zach, M.; Faber, M.; Skala, P.

1998-01-01

The dually transformed path integral of four-dimensional U(1) lattice gauge theory is used for a numerical investigation of multiply charged systems and the interaction between flux tubes. For this aim, it is convenient to implement periodically closed flux tubes (torelons) in the dual formulation. We calculate the free energy as well as the total electro-magnetic energy of doubly charged flux tubes as a function of the coupling β. The main results are that the string tension scales proportionally to the charge (contrary to the Coulomb potential) and in the range 0.9<β<1.0 we find a clear signal for attraction between flux tubes. (orig.)

A method to align a bent crystal for channeling experiments by using quasichanneling oscillations

Science.gov (United States)

Sytov, A. I.; Guidi, V.; Tikhomirov, V. V.; Bandiera, L.; Bagli, E.; Germogli, G.; Mazzolari, A.; Romagnoni, M.

2018-04-01

A method to calculate both the bent crystal angle of alignment and radius of curvature by using only one distribution of deflection angles has been developed. The method is based on measuring of the angular position of recently predicted and observed quasichanneling oscillations in the deflection angle distribution and consequent fitting of both the radius and angular alignment by analytic formulae. In this paper this method is applied on the example of simulated angular distributions over a wide range of values of both radius and alignment for electrons. It is carried out through the example of (111) nonequidistant planes though this technique is general and could be applied to any kind of planes. In addition, the method application constraints are also discussed. It is shown by simulations that this method, being in fact a sort of beam diagnostics, allows one in a certain case to increase the crystal alignment accuracy as well as to control precisely the radius of curvature inside an accelerator tube without vacuum breaking. In addition, it speeds up the procedure of crystal alignment in channeling experiments, reducing beamtime consuming.

Determining the diffraction properties of a cylindrically bent KAP(001) crystal from 1 to 5 keV

Energy Technology Data Exchange (ETDEWEB)

Haugh, Michael [National Security Technologies, LLC. (NSTec), Mercury, NV (United States); Lee, Joshua [National Security Technologies, LLC. (NSTec), Mercury, NV (United States); Jacoby, Kenneth [National Security Technologies, LLC. (NSTec), Mercury, NV (United States); Christensen, C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Loisel, G. [National Security Technologies, LLC. (NSTec), Mercury, NV (United States), Livermore Operations

2015-08-31

Various crystals are used for the dispersive component of X-ray spectrometers. The crystals are usually bent to meet the desired measurement needs, such as focusing. The bending can change the crystal diffraction properties, thus altering the spectrometer throughput and resolving power. This work concerns measuring the diffraction properties of a potassium acid phthalate (001) [KAP(001)] crystal bent into a circular cylinder segment. The measurement methods using a diode source and a synchrotron source are described. The multi-lamellar model for calculating the diffraction properties of a bent crystal is described. The measurement results are compared to the multi-lamellar model and show qualitative agreement. The measurements show how to make the multi-lamellar calculations a useful estimate. A method is given to make useful estimates of the diffraction properties of the KAP(001) crystal bent into a circular cylinder segment.

Origami tubes assembled into stiff, yet reconfigurable structures and metamaterials.

Science.gov (United States)

Filipov, Evgueni T; Tachi, Tomohiro; Paulino, Glaucio H

2015-10-06

Thin sheets have long been known to experience an increase in stiffness when they are bent, buckled, or assembled into smaller interlocking structures. We introduce a unique orientation for coupling rigidly foldable origami tubes in a "zipper" fashion that substantially increases the system stiffness and permits only one flexible deformation mode through which the structure can deploy. The flexible deployment of the tubular structures is permitted by localized bending of the origami along prescribed fold lines. All other deformation modes, such as global bending and twisting of the structural system, are substantially stiffer because the tubular assemblages are overconstrained and the thin sheets become engaged in tension and compression. The zipper-coupled tubes yield an unusually large eigenvalue bandgap that represents the unique difference in stiffness between deformation modes. Furthermore, we couple compatible origami tubes into a variety of cellular assemblages that can enhance mechanical characteristics and geometric versatility, leading to a potential design paradigm for structures and metamaterials that can be deployed, stiffened, and tuned. The enhanced mechanical properties, versatility, and adaptivity of these thin sheet systems can provide practical solutions of varying geometric scales in science and engineering.

First observation of magnetic moment precession of channeled particles in bent crystals

International Nuclear Information System (INIS)

Chen, D.; Albuquerque, I.F.; Baublis, V.V.; Bondar, N.F.; Carrigan, R.A. Jr.; Cooper, P.S.; Lisheng, D.; Denisov, A.S.; Dobrovolsky, A.V.; Dubbs, T.; Endler, A.M.F.; Escobar, C.O.; Foucher, M.; Golovtsov, V.L.; Goritchev, P.A.; Gottschalk, H.; Gouffon, P.; Grachev, V.T.; Khanzadeev, A.V.; Kubantsev, M.A.; Kuropatkin, N.P.; Lach, J.; Lang Pengfei; Lebedenko, V.N.; Li Chengze; Li Yunshan; Mahon, J.R.P.; McCliment, E.; Morelos, A.; Newsom, C.; Pommot Maia, M.C.; Samsonov, V.M.; Schegelsky, V.A.; Shi Huanzhang; Smith, V.J.; Sun, C.R.; Tang Fukun; Terentyev, N.K.; Timm, S.; Tkatch, I.I.; Uvarov, L.N.; Vorobyov, A.A.; Yan Jie; Zhao Wenheng; Zheng Shuchen; Zhong Yuanyuan

1992-01-01

Spin precession of channeled particles in bent crystals has been observed for the first time. Polarized Σ + were channeled using bent Si crystals. These crystals provided an effective magnetic field of 45 T which resulted in a measured spin precession of 60±17 degree. This agrees with the prediction of 62±2 degree using the world average of Σ + magnetic moment measurements. This new technique gives a Σ + magnetic moment of (2.40±0.46±0.40)μ N , where the quoted uncertainties are statistical and systematic, respectively. We see no evidence of depolarization in the channeling process

The free energy profile of tubulin straight-bent conformational changes, with implications for microtubule assembly and drug discovery.

Directory of Open Access Journals (Sweden)

Lili X Peng

2014-02-01

Full Text Available αβ-tubulin dimers need to convert between a 'bent' conformation observed for free dimers in solution and a 'straight' conformation required for incorporation into the microtubule lattice. Here, we investigate the free energy landscape of αβ-tubulin using molecular dynamics simulations, emphasizing implications for models of assembly, and modulation of the conformational landscape by colchicine, a tubulin-binding drug that inhibits microtubule polymerization. Specifically, we performed molecular dynamics, potential-of-mean force simulations to obtain the free energy profile for unpolymerized GDP-bound tubulin as a function of the ∼12° intradimer rotation differentiating the straight and bent conformers. Our results predict that the unassembled GDP-tubulin heterodimer exists in a continuum of conformations ranging between straight and bent, but, in agreement with existing structural data, suggests that an intermediate bent state has a lower free energy (by ∼1 kcal/mol and thus dominates in solution. In agreement with predictions of the lattice model of microtubule assembly, lateral binding of two αβ-tubulins strongly shifts the conformational equilibrium towards the straight state, which is then ∼1 kcal/mol lower in free energy than the bent state. Finally, calculations of colchicine binding to a single αβ-tubulin dimer strongly shifts the equilibrium toward the bent states, and disfavors the straight state to the extent that it is no longer thermodynamically populated.

Deformation mechanisms of bent Si nanowires governed by the sign and magnitude of strain

Energy Technology Data Exchange (ETDEWEB)

Wang, Lihua, E-mail: wlh@bjut.edu.cn, E-mail: xdhan@bjut.edu.cn, E-mail: j.zou@uq.edu.au [Beijing Key Lab of Microstructure and Property of Advanced Material, Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing 100124 (China); Materials Engineering, The University of Queensland, Brisbane, QLD 4072 (Australia); Kong, Deli; Xin, Tianjiao; Shu, Xinyu; Zheng, Kun; Xiao, Lirong; Sha, Xuechao; Lu, Yan; Han, Xiaodong, E-mail: wlh@bjut.edu.cn, E-mail: xdhan@bjut.edu.cn, E-mail: j.zou@uq.edu.au [Beijing Key Lab of Microstructure and Property of Advanced Material, Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing 100124 (China); Zhang, Ze [Department of Materials Science, Zhejiang University, Hangzhou 310008 (China); Zou, Jin, E-mail: wlh@bjut.edu.cn, E-mail: xdhan@bjut.edu.cn, E-mail: j.zou@uq.edu.au [Materials Engineering, The University of Queensland, Brisbane, QLD 4072 (Australia); Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, QLD 4072 (Australia)

2016-04-11

In this study, the deformation mechanisms of bent Si nanowires are investigated at the atomic scale with bending strain up to 12.8%. The sign and magnitude of the applied strain are found to govern their deformation mechanisms, in which the dislocation types (full or partial dislocations) can be affected by the sign (tensile or compressive) and magnitude of the applied strain. In the early stages of bending, plastic deformation is controlled by 60° full dislocations. As the bending increases, Lomer dislocations can be frequently observed. When the strain increases to a significant level, 90° partial dislocations induced from the tensile surfaces of the bent nanowires are observed. This study provides a deeper understanding of the effect of the sign and magnitude of the bending strain on the deformation mechanisms in bent Si nanowires.

Radionuclides gauges. Gauges designed for permanent installation

International Nuclear Information System (INIS)

1987-06-01

This present norm determines, for radionuclides gauges designed for permanent installation, the characteristics that these gauges should satisfied in their construction and performance to respect the prescriptions. It indicates the testing methods which permit to verify the agreement, gives a classification of gauges and specifies the indications to put on the emitter block [fr

Bent Electro-Absorption Modulator

DEFF Research Database (Denmark)

2002-01-01

by applying a variable electric or electronmagnetic field. The modulation of the complex refractive index results in a modulation of the refractive index contrast and the absorption coefficient for the waveguide at the frequency of the light. By carefully adjusting the composition of the semiconducting...... components and the applied electric field in relation to the frequency of the modulated radiation, the bending losses (and possibly coupling losses) will provide extinction of light guided by the bent waveguide section. The refractive index contract may be modulated while keeping the absorption coefficient......The present invention relates to a method and a device for modulating optical signals based on modulating bending losses in bend, quantum well semiconductor waveguide sections. The complex refractive index of the optical active semiconducting components of the waveguide section is modulated...

Fourier acceleration in lattice gauge theories. I. Landau gauge fixing

International Nuclear Information System (INIS)

Davies, C.T.H.; Batrouni, G.G.; Katz, G.R.; Kronfeld, A.S.; Lepage, G.P.; Wilson, K.G.; Rossi, P.; Svetitsky, B.

1988-01-01

Fourier acceleration is a useful technique which can be applied to many different numerical algorithms in order to alleviate the problem of critical slowing down. Here we describe its application to an optimization problem in the simulation of lattice gauge theories, that of gauge fixing a configuration of link fields to the Landau gauge (partial/sub μ/A/sup μ/ = 0). We find that a steepest-descents method of gauge fixing link fields at β = 5.8 on an 8 4 lattice can be made 5 times faster using Fourier acceleration. This factor will grow as the volume of the lattice is increased. We also discuss other gauges that are useful to lattice-gauge-theory simulations, among them one that is a combination of the axial and Landau gauges. This seems to be the optimal gauge to impose for the Fourier acceleration of two other important algorithms, the inversion of the fermion matrix and the updating of gauge field configurations

Gauge-fixing parameter dependence of two-point gauge-variant correlation functions

International Nuclear Information System (INIS)

Zhai, C.

1996-01-01

The gauge-fixing parameter ξ dependence of two-point gauge-variant correlation functions is studied for QED and QCD. We show that, in three Euclidean dimensions, or for four-dimensional thermal gauge theories, the usual procedure of getting a general covariant gauge-fixing term by averaging over a class of covariant gauge-fixing conditions leads to a nontrivial gauge-fixing parameter dependence in gauge-variant two-point correlation functions (e.g., fermion propagators). This nontrivial gauge-fixing parameter dependence modifies the large-distance behavior of the two-point correlation functions by introducing additional exponentially decaying factors. These factors are the origin of the gauge dependence encountered in some perturbative evaluations of the damping rates and the static chromoelectric screening length in a general covariant gauge. To avoid this modification of the long-distance behavior introduced by performing the average over a class of covariant gauge-fixing conditions, one can either choose a vanishing gauge-fixing parameter or apply an unphysical infrared cutoff. copyright 1996 The American Physical Society

Deflection of high energy channeled charged particles by elastically bent silicon single crystals

International Nuclear Information System (INIS)

Gibson, W.M.; Kim, I.J.; Pisharodoy, M.; Salman, S.M.; Sun, C.R.; Wang, G.H.; Wijayawardana, R.; Forster, J.S.; Mitchell, I.V.; Baker, S.I.; Carrigan, R.A. Jr.; Toohig, T.E.; Avdeichikov, V.V.; Ellison, J.A.; Siffert, P.

1984-01-01

An experiment has been carried out to observe the deflection of charged particles by planar channeling in bent single crystals of silicon for protons with energy up to 180 GeV. Anomolous loss of particles from the center point of a three point bending apparatus was observed at high incident particle energy. This effect has been exploited to fashion a 'dechanneling spectrometer' to study dechanneling effects due to centripital displacement of channeled particle trajectories in a bent crystal. The bending losses generally conform to the predictions of calculations based on a classical model. (orig.)

Shuttle Ku-band bent-pipe implementation considerations. [for Space Shuttle digital communication systems

Science.gov (United States)

Batson, B. H.; Seyl, J. W.; Huth, G. K.

1977-01-01

This paper describes an approach for relay of data-modulated subcarriers from Shuttle payloads through the Shuttle Ku-band communications subsystem (and subsequently through a tracking and data relay satellite system to a ground terminal). The novelty is that a channel originally provided for baseband digital data is shown to be suitable for this purpose; the resulting transmission scheme is referred to as a narrowband bent-pipe scheme. Test results demonstrating the validity of the narrowband bent-pipe mode are presented, and limitations on system performance are described.

46 CFR 52.01-110 - Water-level indicators, water columns, gauge-glass connections, gauge cocks, and pressure gauges...

Science.gov (United States)

2010-10-01

... § 52.01-110 Water-level indicators, water columns, gauge-glass connections, gauge cocks, and pressure... 46 Shipping 2 2010-10-01 2010-10-01 false Water-level indicators, water columns, gauge-glass connections, gauge cocks, and pressure gauges (modifies PG-60). 52.01-110 Section 52.01-110 Shipping COAST...

Bent Shaped 1,3,4-Oxadiazole/Thiadiazole heterocyclic rings ...

Indian Academy of Sciences (India)

Two series of bent shaped 1,3,4-oxadiazole/thiadiazole heterocyclic ring containing liquid crystalline (LC) compounds were synthesized and characterized by FT-IR, 1H, 13C-NMR and ESI-Mass spectro-scopic techniques. Liquid crystal properties were investigated by polarized optical microscopy and differential scanning ...

Manipulation of hadron beams with bent crystals in circular accelerators

CERN Document Server

Rossi, R; Redaelli, S; Scandale, W

2016-01-01

Over the past years the understanding and use of coherent interactions of charged particles with ordered crystal lattices has achieved excellent results. Improving collimation of hadron beams in circular accelerators, like the Large Hadron Collider (LHC) of the European Council for Nuclear Research (CERN), it is one of the possible applications. The aim of the UA9 experiment is to demonstrate the feasibility of a two-stage collimation system in the CERN-SPS : the first stage is a bent crystal oriented for an optimal channeling of the incoming halo particles; the second stage is a massive absorber. Two crystals were installed in the LHC last year and a test of crystal assisted collimation at the highest energy will be possible as early as 2015. Finally, the UA9 Collaboration is investigating extraction of particles from a circular accelerator, based on bent crystals.

Alcohol sensor based on u-bent hetero-structured fiber optic

Science.gov (United States)

Patrialova, Sefi N.; Hatta, Agus M.; Sekartedjo, Sekartedjo

2016-11-01

A sensor based on a fiber optic hetero-structure to determine the concentration of alcohol has been proposed. The structure of the sensing probe in this research is a singlemode-multimode-singlemode (SMS) which bent into Ushaped and soon called as SMS u-bent. The SMS structure was chosen to get a higher sensitivity. This research utilizes the principle of multimode interference and evanescent field by modifying the cladding with various alcohol concentration. Testing of the sensor's performance has been done by measuring the sensor's power output response to the length of the SMS fiber optic, bending diameter, and alcohol concentration. Based on the experiment result, the ubent SMS fiber optic with 50 mm bending diameter and 63 mm MMF lenght has the highest sensitivity, 3.87 dB/% and the minimum resolution, 0.26 x 10-3 %.

Gauge theories

International Nuclear Information System (INIS)

Lee, B.W.

1976-01-01

Some introductory remarks to Yang-Mills fields are given and the problem of the Coulomb gauge is considered. The perturbation expansion for quantized gauge theories is discussed and a survey of renormalization schemes is made. The role of Ward-Takahashi identities in gauge theories is discussed. The author then discusses the renormalization of pure gauge theories and theories with spontaneously broken symmetry. (B.R.H.)

In-situ growth of AuNPs on WS2@U-bent optical fiber for evanescent wave absorption sensor

Science.gov (United States)

Zhang, Suzhen; Zhao, Yuefeng; Zhang, Chao; Jiang, Shouzhen; Yang, Cheng; Xiu, Xianwu; Li, Chonghui; Li, Zhen; Zhao, Xiaofei; Man, Baoyuan

2018-05-01

The sensitivity of the evanescent wave absorption sensor is always a hot topic which has been attracted researchers' discussion. It is still a challenge for developing the effective sensor to sensitively detect some biochemical molecules solution in a simple and low-cost way. In this paper, an evanescent wave absorption (EWA) sensor has been presented based on the U-bent multimode fiber coated with tungsten disulfide (WS2) film and in-situ growth of gold nanoparticles (AuNPs) for the detection of ethanol solution and sodium chloride (NaCl) solution. Benefitted from the effective light coupling produced between U-bent probe and AuNPs, we attained the optimal size of the AuNPs by changing the reaction time between WS2 and tetrachloroauric acid (HAuCl4). With the AuNPs/WS2@U-bent optical fiber, we discussed the behaviors of EWA sensor, such as sensitivity, reproducibility, fast response-recovery time and stability. The sensitivity (△A/△C) of the proposed AuNPs/WS2@U-bent optical fiber EWA sensor is 0.65 for the detection of the ethanol solution. Besides, the AuNPs/WS2@U-bent optical fiber EWA sensor exhibits high sensitivity in detection of the sodium chloride (NaCl), which can reach 1.5 when the proposed sensor was immersed into NaCl solution. Our work demonstrates that the U-bent optical fiber EWA sensor may have promising applications in testing the solution of concentration.

Nucleonic gauges

International Nuclear Information System (INIS)

Sowerby, B.D.

1982-01-01

Techniques employed in nuclear gauges for the measurement of level, thickness, density and moisture are described. The gauges include both transmission and backscatter gauges and utilize alpha particles, beta particles, neutrons or gamma radiation

Rarefied, superorbital flows in an expansion tube

Energy Technology Data Exchange (ETDEWEB)

Wheatley, V.; Chiu, H.S.; Jacobs, P.A.; Macrossan, M.N.; Mee, D.J.; Morgan, R.G.

2004-04-01

This paper describes a free-piston driven expansion tube and its instrumentation. The facility is used to generate rarefied flows at speeds of approximately 10 km/s. Although the flow in the tube itself is in the continuum regime, rarefied flow conditions are achieved by allowing the test gas to further expand as a free jet into the facility's test section. The test flow is surveyed to provide bar-gauge pressure measurements. Numerical simulation is then used to describe more fully the test flow properties. The flows produced are suitable for the aerodynamic testing of small models at superorbital speeds and should provide data that are suitable for the calibration of Direct Simulation Monte-Carlo codes. (author)

Compensation for gravitational sag of bent mirror

Energy Technology Data Exchange (ETDEWEB)

Mao, Chengwen; Jiang, Hui; He, Yan; Liang, Dongxu; Lan, Xuying; Yan, Shuai [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, CAS, Shanghai 201800 (China); Shu, De-ming [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); Li, Aiguo, E-mail: aiguo.li@sinap.ac.cn [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, CAS, Shanghai 201800 (China)

2017-05-01

The gravitational sag of aspheric bent mirrors with face-up or face-down geometry produces a nonnegligible optical error. As an effective compensation, width optimization is used to match the combined effects of the gravitational and bending moments. This method is described by analytical expressions and two calculation algorithms. The results of theoretical simulations and finite element analysis have proved that this method can reduce the slope error resulting from gravitational sag to the level of nano radians.

Compensation for gravitational sag of bent mirror

International Nuclear Information System (INIS)

Mao, Chengwen; Jiang, Hui; He, Yan; Liang, Dongxu; Lan, Xuying; Yan, Shuai; Shu, De-ming; Li, Aiguo

2017-01-01

The gravitational sag of aspheric bent mirrors with face-up or face-down geometry produces a nonnegligible optical error. As an effective compensation, width optimization is used to match the combined effects of the gravitational and bending moments. This method is described by analytical expressions and two calculation algorithms. The results of theoretical simulations and finite element analysis have proved that this method can reduce the slope error resulting from gravitational sag to the level of nano radians.

Vacuum gauges

International Nuclear Information System (INIS)

Power, B.D.; Priestland, C.R.D.

1978-01-01

This invention relates to vacuum gauges, particularly of the type known as Penning gauges, which are cold cathode ionisation gauges, in which a magnetic field is used to lengthen the electron path and thereby increase the number of ions produced. (author)

Spatially resolved analysis of short-range structure perturbations in a plastically bent molecular crystal

Science.gov (United States)

Panda, Manas K.; Ghosh, Soumyajit; Yasuda, Nobuhiro; Moriwaki, Taro; Mukherjee, Goutam Dev; Reddy, C. Malla; Naumov, Panče

2015-01-01

The exceptional mechanical flexibility observed with certain organic crystals defies the common perception of single crystals as brittle objects. Here, we describe the morphostructural consequences of plastic deformation in crystals of hexachlorobenzene that can be bent mechanically at multiple locations to 360° with retention of macroscopic integrity. This extraordinary plasticity proceeds by segregation of the bent section into flexible layers that slide on top of each other, thereby generating domains with slightly different lattice orientations. Microscopic, spectroscopic and diffraction analyses of the bent crystal showed that the preservation of crystal integrity when stress is applied on the (001) face requires sliding of layers by breaking and re-formation of halogen-halogen interactions. Application of stress on the (100) face, in the direction where π···π interactions dominate the packing, leads to immediate crystal disintegration. Within a broader perspective, this study highlights the yet unrecognized extraordinary malleability of molecular crystals with strongly anisotropic supramolecular interactions.

Non-symmetrical bent-shaped compounds containing chiral moiety

Czech Academy of Sciences Publication Activity Database

Novotná, Vladimíra; Mieczkowska, B.; Hamplová, Věra; Domján, A.; Pociecha, D.; Kašpar, Miroslav; Fodor-Csorba, K.

2012-01-01

Roč. 39, č. 10 (2012), s. 1252-1260 ISSN 0267-8292 R&D Projects: GA ČR(CZ) GAP204/11/0723 Institutional research plan: CEZ:AV0Z10100520 Keywords : bent-shaped mesogen * columnar phase * ferroelectricity * polar switching Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.959, year: 2012 http://www.tandfonline.com/doi/abs/10.1080/02678292.2012.714485

Gauge theories

International Nuclear Information System (INIS)

Kenyon, I.R.

1986-01-01

Modern theories of the interactions between fundamental particles are all gauge theories. In the case of gravitation, application of this principle to space-time leads to Einstein's theory of general relativity. All the other interactions involve the application of the gauge principle to internal spaces. Electromagnetism serves to introduce the idea of a gauge field, in this case the electromagnetic field. The next example, the strong force, shows unique features at long and short range which have their origin in the self-coupling of the gauge fields. Finally the unification of the description of the superficially dissimilar electromagnetic and weak nuclear forces completes the picture of successes of the gauge principle. (author)

The string unification of gauge couplings and gauge kinetic mixings

International Nuclear Information System (INIS)

Hattori, Chuichiro; Matsuda, Masahisa; Matsuoka, Takeo; Mochinaga, Daizo.

1993-01-01

In the superstring models we have not only the complete 27 multiplets of E 6 but also extra incomplete (27+27-bar) chiral supermultiplets being alive at low energies. Associated with these additional multiplets, when the gauge symmetry contains more than one U(1) gauge group, there may exist gauge kinetic mixings among these U(1) gauge groups. In such cases the effect of gauge kinetic mixings should be incorporated into the study of unification of gauge couplings. We study these interesting effects systematically in these models. The string threshold effect is also taken into account. It is found that in the four-generation models we do not have an advisable solution of string unification of gauge couplings consistent with experimental values at the electroweak scale. We also discuss the possible scenarios to solve this problem. (author)

Gauge fields

International Nuclear Information System (INIS)

Mills, R.

1989-01-01

This article is a survey of the history and ideas of gauge theory. Described here are the gradual emergence of symmetry as a driving force in the shaping of physical theory; the elevation of Noether's theorem, relating symmetries to conservation laws, to a fundamental principle of nature; and the force of the idea (''the gauge principle'') that the symmetries of nature, like the interactions themselves, should be local in character. The fundamental role of gauge fields in mediating the interactions of physics springs from Noether's theorem and the gauge principle in a remarkably clean and elegant way, leaving, however, some tantalizing loose ends that might prove to be the clue to a future deeper level of understanding. The example of the electromagnetic field as the prototype gauge theory is discussed in some detail and serves as the basis for examining the similarities and differences that emerge in generalizing to non-Abelian gauge theories. The article concludes with a brief examination of the dream of total unification: all the forces of nature in a single unified gauge theory, with the differences among the forces due to the specific way in which the fundamental symmetries are broken in the local environment

Photoelastic investigation of the stresses in mitred bent cylinders under bending, (1)

International Nuclear Information System (INIS)

Sawa, Yoshiaki

1982-01-01

Recently large bore pipes have been frequently used, and the techniques of jointing such pipes are important technical problem. As for the actual design of pipe joints, the stress condition has not been sufficiently clarified. When two same diameter pipes are jointed making a certain angle, mitred bent pipes are often used from economical and technical viewpoints as the pipes become large bore. In a mitred bent pipe, there is a sharp edge in its pipe joint, at which the measurement of stress and strain is difficult. The stress distribution near the joint when a mitred bent pipe is subjected to the bending moment in the plane containing the axes of both pipes was analyzed by the freezing three-dimensional photo-elastic method, and not only the bending stress in the joint but also the hoop stress were determined by the wedge method. This stress concentration phenomenon is due to the whole structural factor of the intersection of two pipes and the local stress peak factor caused at the wedge-shaped edge formed in the intersection. The local form of the intersection plays important role in the stress concentration. The manufactured models, the method of loading, slices and the wedge method, and the stress distribution are reported. (Kako, I.)

Duplex-tube sodium-indication steam generator

International Nuclear Information System (INIS)

Matal, O.; Martoch, J.

1984-01-01

The steam generator with duplex tubes and sodium indication is connected to the main sodium input and output via the inlet and outlet chambers and has indication spaces connected to the interspaces of the duplex tubes. The first indication space is linked with the auxiliary inlet pipe to the inlet chamber and the second indication space is connected with the auxiliary pipe to the outlet chamber. Mounted to the auxiliary inlet pipe is at least one closure, i.e., a valve or electromagnetic stop. Mounted on the auxiliary outlet pipe is an indication sensor, e.g., a sodium flow sensor. At least one indication space is provided with an alarm sensor, e.g., a thermocouple, a pressure gauge and one sensor to monitor the hydrogen content of sodium. (J.P.)

A strain gauge

DEFF Research Database (Denmark)

2016-01-01

The invention relates to a strain gauge of a carrier layer and a meandering measurement grid positioned on the carrier layer, wherein the strain gauge comprises two reinforcement members positioned on the carrier layer at opposite ends of the measurement grid in the axial direction....... The reinforcement members are each placed within a certain axial distance to the measurement grid with the axial distance being equal to or smaller than a factor times the grid spacing. The invention further relates to a multi-axial strain gauge such as a bi-axial strain gauge or a strain gauge rosette where each...... of the strain gauges comprises reinforcement members. The invention further relates to a method for manufacturing a strain gauge as mentioned above....

Limits to the Recognizability of Flaws in Non-Destructive Testing Steam-Generator Tubes for Nuclear-Power Plants

International Nuclear Information System (INIS)

Kuhlmann, A.; Adamsky, F.-J.

1965-01-01

In the Federal Republic of Germany there are nuclear reactors under construction with steam generators inside the reactor pressure-vessel. As a result design repairs of steam- generator tubes are very difficult and cause large shut-down times of the nuclear-power plant. It is known that numerous troubles in operating conventional power plants are results of steam-generator tube damages. Because of the high total costs of these reactors it. is necessary to construct the steam generators especially in such a manner that the load factor of the power plant is as high as possible. The Technischer Überwachungs-Verein Rheinland was charged to supervise and to test fabrication and construction of the steam generators to see that this part of the plant was as free of defects as possible. The experience gained during this work is of interest for manufacture and construction of steam generators for nuclear-power plants in general. This paper deals with the efficiency limits of non-destructive testing steam-generator tubes. The following tests performed will be discussed in detail: (a) Automatic ultrasonic testing of the straight tubes in the production facility; (b) Combined ultrasonic and radiographic testing of the bent tubes and tube weldings; (c) Other non-destructive tests. (author) [fr

Superaxial gauges

International Nuclear Information System (INIS)

Kummer, W.; Mistelberger, H.; Schaller, P.; Schweda, M.

1989-01-01

Supersymmetric gauge theories can be suitably quantized in non-supersymmetric 'superaxial' gauges without abolishing the basic advantages of the superfield technique. In this review the state of the art is presented. It includes the proof of renormalization and the proof of gauge independence and supersymmetry of observable physical quantities. (author)

Abelian gauge theories with tensor gauge fields

International Nuclear Information System (INIS)

Kapuscik, E.

1984-01-01

Gauge fields of arbitrary tensor type are introduced. In curved space-time the gravitational field serves as a bridge joining different gauge fields. The theory of second order tensor gauge field is developed on the basis of close analogy to Maxwell electrodynamics. The notion of tensor current is introduced and an experimental test of its detection is proposed. The main result consists in a coupled set of field equations representing a generalization of Maxwell theory in which the Einstein equivalence principle is not satisfied. (author)

Gauge invariance rediscovered

International Nuclear Information System (INIS)

Moriyasu, K.

1978-01-01

A pedagogical approach to gauge invariance is presented which is based on the analogy between gauge transformations and relativity. By using the concept of an internal space, purely geometrical arguments are used to teach the physical ideas behind gauge invariance. Many of the results are applicable to general gauge theories

Pre-bent elastic stable intramedullary nail fixation for distal radial shaft fractures in children.

Science.gov (United States)

Ge, Yi-hua; Wang, Zhi-gang; Cai, Hai-qing; Yang, Jie; Xu, Yun-lan; Li, Yu-chan; Zhang, Yu-chen; Chen, Bo-chang

2010-08-01

To investigate the functional and radiographic outcomes of pre-bent elastic stable intramedullary nail in treatment of distal radial shaft fractures in children. From January 2006 to December 2008, 18 children with distal radial shaft fracture were treated by close reduction and internal fixation with a pre-bent elastic stable intramedullary nail. The age range was from 5 years to 15 years, with an average of 9 years and 8 months. The minimum follow-up was 12 months. All fractures maintained good alignment postoperatively, and 94.4% (17/18) of the patients regained a full range of rotation of the forearm. One patient has limitation of rotation to less than 10°, this had improved by final follow-up. Complications included soft tissue irritation at the site of nail insertion in one patient and transient scar hypersensitivity in another. Fixation with a pre-bent elastic stable intramedullary nail is an effective, safe and convenient method for treating distal radial shaft fractures in children. © 2010 Tianjin Hospital and Blackwell Publishing Asia Pty Ltd.

Some observations on interpolating gauges and non-covariant gauges

Indian Academy of Sciences (India)

We discuss the viability of using interpolating gauges to define the non-covariant gauges starting from the covariant ones. We draw attention to the need for a very careful treatment of boundary condition defining term. We show that the boundary condition needed to maintain gauge-invariance as the interpolating parameter ...

Analysis of piston behavior according to eccentricity ratio of disk in bent-axis type piston pump

International Nuclear Information System (INIS)

Baek, Il Hyun; Cho, Ihn Sung; Jung, Jae Youn; Hong, Lu

2008-01-01

To improve the performance of the bent-axis type axial piston pump driven by the tapered piston, it is necessary to know the driving characteristics and mechanism of the tapered piston and the cylinder block. Since each piston not only rotates on its axis and reciprocates in the cylinder bore but also revolves around the axis of the driving shaft, it is difficult to analyze the driving mechanism theoretically. The theoretical mechanism for the bent-axis type axial piston pump is studied by using the geometrical method. The driving range of the tapered piston is determined by theoretical equations. The results show that the cylinder block is driven by one tapered piston in a limited range and the core parameters such as the tilting angle of the piston and the ahead delay angle influence performance of the bent-axis type axial piston pump

Inflation and gauge mediation in supersymmetric gauge theory

International Nuclear Information System (INIS)

Nakai, Yuichiro; Sakai, Manabu

2011-01-01

We propose a simple high-scale inflationary scenario based on a phenomenologically viable model with direct gauge mediation of low-scale supersymmetry breaking. Hybrid inflation occurs in a hidden supersymmetry breaking sector. Two hierarchical mass scales to reconcile both high-scale inflation and gauge mediation are necessary for the stability of the metastable supersymmetry breaking vacuum. Our scenario is also natural in light of the Landau pole problem of direct gauge mediation. (author)

Gauge-invariant dynamical quantities of QED with decomposed gauge potentials

International Nuclear Information System (INIS)

Zhou Baohua; Huang Yongchang

2011-01-01

We discover an inner structure of the QED system; i.e., by decomposing the gauge potential into two orthogonal components, we obtain a new expansion of the Lagrangian for the electron-photon system, from which, we realize the orthogonal decomposition of the canonical momentum conjugate to the gauge potential with the canonical momentum's two components conjugate to the gauge potential's two components, respectively. Using the new expansion of Lagrangian and by the general method of field theory, we naturally derive the gauge invariant separation of the angular momentum of the electron-photon system from Noether theorem, which is the rational one and has the simplest form in mathematics, compared with the other four versions of the angular momentum separation available in literature. We show that it is only the longitudinal component of the gauge potential that is contained in the orbital angular momentum of the electron, as Chen et al. have said. A similar gauge invariant separation of the momentum is given. The decomposed canonical Hamiltonian is derived, from which we construct the gauge invariant energy operator of the electron moving in the external field generated by a proton [Phys. Rev. A 82, 012107 (2010)], where we show that the form of the kinetic energy containing the longitudinal part of the gauge potential is due to the intrinsic requirement of the gauge invariance. Our method provides a new perspective to look on the nucleon spin crisis and indicates that this problem can be solved strictly and systematically.

Gauge symmetry breaking

International Nuclear Information System (INIS)

Weinberg, S.

1976-01-01

The problem of how gauge symmetries of the weak interactions get broken is discussed. Some reasons why such a heirarchy of gauge symmetry breaking is needed, the reason gauge heirarchies do not seem to arise in theories of a given and related type, and the implications of theories with dynamical symmetry breaking, which can exhibit a gauge hierarchy

Local gauge coupling running in supersymmetric gauge theories on orbifolds

International Nuclear Information System (INIS)

Hillenbach, M.

2007-01-01

By extending Feynman's path integral calculus to fields which respect orbifold boundary conditions we provide a straightforward and convenient framework for loop calculations on orbifolds. We take advantage of this general method to investigate supersymmetric Abelian and non-Abelian gauge theories in five, six and ten dimensions where the extra dimensions are compactified on an orbifold. We consider hyper and gauge multiplets in the bulk and calculate the renormalization of the gauge kinetic term which in particular allows us to determine the gauge coupling running. The renormalization of the higher dimensional theories in orbifold spacetimes exhibits a rich structure with three principal effects: Besides the ordinary renormalization of the bulk gauge kinetic term the loop effects may require the introduction of both localized gauge kinetic terms at the fixed points/planes of the orbifold and higher dimensional operators. (orig.)

Local gauge coupling running in supersymmetric gauge theories on orbifolds

Energy Technology Data Exchange (ETDEWEB)

Hillenbach, M.

2007-11-21

By extending Feynman's path integral calculus to fields which respect orbifold boundary conditions we provide a straightforward and convenient framework for loop calculations on orbifolds. We take advantage of this general method to investigate supersymmetric Abelian and non-Abelian gauge theories in five, six and ten dimensions where the extra dimensions are compactified on an orbifold. We consider hyper and gauge multiplets in the bulk and calculate the renormalization of the gauge kinetic term which in particular allows us to determine the gauge coupling running. The renormalization of the higher dimensional theories in orbifold spacetimes exhibits a rich structure with three principal effects: Besides the ordinary renormalization of the bulk gauge kinetic term the loop effects may require the introduction of both localized gauge kinetic terms at the fixed points/planes of the orbifold and higher dimensional operators. (orig.)

Solution of the gauge identities in the axial gauge

International Nuclear Information System (INIS)

Delbourgo, R.

1981-01-01

Starting from the spectral representation of the two-point functions in the axial gauge, the gauge identities are solved so as to express the higher-point Green functions linearly in terms of the two-point spectral function. The four-point functions are an important input for investigations of scalar electrodynamics and vector chromodynamics based on the gauge technique. (author)

Lattice gauge theory

International Nuclear Information System (INIS)

Mack, G.

1982-01-01

After a description of a pure Yang-Mills theory on a lattice, the author considers a three-dimensional pure U(1) lattice gauge theory. Thereafter he discusses the exact relation between lattice gauge theories with the gauge groups SU(2) and SO(3). Finally he presents Monte Carlo data on phase transitions in SU(2) and SO(3) lattice gauge models. (HSI)

Gauge glass

International Nuclear Information System (INIS)

Nielsen, H.B.; Brene, N.

1984-12-01

The fundamental laws of nature may be truely random, or they may be so complicated that a random description is adequate. With this philosophy we examine various ways in which a lattice gauge theory (at the Planck scale) can be generalized. Without here giving up a regular lattice structure (which we really ought to do) we consider two generalizations. Making the action (quenched) random has the effect that the gauge group tends to break down and some gauge bosons become massive, unless the gauge group has special properties: no noncentral corners in the geometry of conjugacy classes and furthermore a connected center. Making the concept of gauge transformation more general has a symmetry breaking effect for groups with outer automorphisms. A study of SU 5 -breaking in the context of the first breakdown mechanism (D. Bennett, E. Buturovic and H. B. Nielsen) is shortly reviewed. (orig.)

Electromagnetic velocity gauge: use of multiple gauges, time response, and flow perturbations

International Nuclear Information System (INIS)

Erickson, L.M.; Johnson, C.B.; Parker, N.L.; Vantine, H.C.; Weingart, R.C.; Lee, R.S.

1981-01-01

We have developed an in-situ electromagnetic velocity (EMV) gauge system for use in multiple-gauge studies of initiating and detonating explosives. We have also investigated the risetime of the gauge and the manner in which it perturbs a reactive flow. We report on the special precautions that are necessary in multiple gauge experiments to reduce lead spreading, simplify target fabrication problems and minimize cross talk through the conducting explosive. Agreement between measured stress records and calculations from multiple velocity gauge data give us confidence that our velocity gauges are recording properly. We have used laser velocity interferometry to measure the gauge risetime in polymethyl methacrylate (PMMA). To resolve the difference in the two methods, we have examined hydrodynamic and material rate effects. In addition, we considered the effects of shock tilt, electronic response and magntic diffusion on the gauge's response time

Planar channeling and quasichanneling oscillations in a bent crystal

International Nuclear Information System (INIS)

Sytov, A.I.; Guidi, V.; Bagli, E.; Bandiera, L.; Germogli, G.; Mazzolari, A.; Tikhomirov, V.V.

2016-01-01

Particles passing through a crystal under planar channeling are captured by a continuous potential and experience transverse oscillations in their motion. As channeled particles approach the atomic planes, they are likely to be dechanneled. This effect is being used in ion-beam analysis with MeV energy. We study this effect in a bent crystal for positive and negative particles within a wide range of energies in sight of application of such crystals at accelerators. We look for the conditions for the observation or not of channeling oscillations in the deflection angle distribution in experiments where the beam passes through the bent crystal. Indeed a new kind of oscillations in the deflection angle distribution, strictly related to the motion of over-barrier particles, i.e. quasichanneled particles, is predicted. Such oscillations, named planar quasichanneling oscillations, possess a different nature than channeling oscillations. Through computer simulation, we study this effect and provided a theoretical interpretation for them. We show that channeling oscillations can be observed only for positive particles while quasichanneling oscillations can exist for particles with either sign. The conditions for experimental observation of channeling and quasichanneling oscillations at existing accelerators with available crystal are found and optimized. (orig.)

Planar channeling and quasichanneling oscillations in a bent crystal

Energy Technology Data Exchange (ETDEWEB)

Sytov, A.I. [Universita di Ferrara, Dipartimento di Fisica e Scienze della Terra, Ferrara (Italy); Belarusian State University, Research Institute for Nuclear Problems, Minsk (Belarus); INFN, Ferrara (Italy); Guidi, V.; Bagli, E.; Bandiera, L.; Germogli, G.; Mazzolari, A. [Universita di Ferrara, Dipartimento di Fisica e Scienze della Terra, Ferrara (Italy); INFN, Ferrara (Italy); Tikhomirov, V.V. [Belarusian State University, Research Institute for Nuclear Problems, Minsk (Belarus); INFN, Ferrara (Italy)

2016-02-15

Particles passing through a crystal under planar channeling are captured by a continuous potential and experience transverse oscillations in their motion. As channeled particles approach the atomic planes, they are likely to be dechanneled. This effect is being used in ion-beam analysis with MeV energy. We study this effect in a bent crystal for positive and negative particles within a wide range of energies in sight of application of such crystals at accelerators. We look for the conditions for the observation or not of channeling oscillations in the deflection angle distribution in experiments where the beam passes through the bent crystal. Indeed a new kind of oscillations in the deflection angle distribution, strictly related to the motion of over-barrier particles, i.e. quasichanneled particles, is predicted. Such oscillations, named planar quasichanneling oscillations, possess a different nature than channeling oscillations. Through computer simulation, we study this effect and provided a theoretical interpretation for them. We show that channeling oscillations can be observed only for positive particles while quasichanneling oscillations can exist for particles with either sign. The conditions for experimental observation of channeling and quasichanneling oscillations at existing accelerators with available crystal are found and optimized. (orig.)

Gauge symmetry breaking in gauge theories -- in search of clarification

NARCIS (Netherlands)

Friederich, Simon

2013-01-01

The paper investigates the spontaneous breaking of gauge symmetries in gauge theories from a philosophical angle, taking into account the fact that the notion of a spontaneously broken local gauge symmetry, though widely employed in textbook expositions of the Higgs mechanism, is not supported by

Some observations on interpolating gauges and non-covariant gauges

International Nuclear Information System (INIS)

Joglekar, Satish D.

2003-01-01

We discuss the viability of using interpolating gauges to define the non-covariant gauges starting from the covariant ones. We draw attention to the need for a very careful treatment of boundary condition defining term. We show that the boundary condition needed to maintain gauge invariance as the interpolating parameter θ varies, depends very sensitively on the parameter variation. We do this with a gauge used by Doust. We also consider the Lagrangian path-integrals in Minkowski space for gauges with a residual gauge-invariance. We point out the necessity of inclusion of an ε-term (even) in the formal treatments, without which one may reach incorrect conclusions. We, further, point out that the ε-term can contribute to the BRST WT-identities in a non-trivial way (even as ε → 0). We point out that these contributions lead to additional constraints on Green's function that are not normally taken into account in the BRST formalism that ignores the ε-term, and that they are characteristic of the way the singularities in propagators are handled. We argue that a prescription, in general, will require renormalization; if at all it is to be viable. (author)

Effective potential for spontaneously broken gauge theories and gauge hierarchies

International Nuclear Information System (INIS)

Hagiwara, T.; Ovrut, B.

1979-01-01

The Appelquist-Carazzone effective-field-theory method, where one uses effective light-field coupling constants dependent on the heavy-field sector, is explicitly shown to be valid for the discussion of the gauge-hierarchy problem in grand unified gauge models. Using the method of functionals we derive an expression for the one-loop approximation to the scalar-field effective potential for spontaneously broken theories in an arbitrary R/sub xi/ gauge. We argue that this potential generates, through its derivatives, valid zero-momentum, one-particle-irreducible vertices for any value of xi (not just the xi→infinity Landau gauge). The equation that the one-loop vacuum correction must satisfy is presented, and we solve this equation for a number of spontaneously broken theories including gauge theories with gauge groups U(1) and SO(3). We find that a one-loop vacuum shift in a massless, non-Goldstone direction occurs via the Coleman-Weinberg mechanism with an effective coupling constant dependent on the heavy-field sector

Volume reflection efficiency for negative particles in bent crystals

Energy Technology Data Exchange (ETDEWEB)

Biryukov, V.M., E-mail: valery.biryukov@ihep.ru

2017-02-10

We suggest a formula for the efficiency of a single volume reflection of negatively charged particles in bent crystal planes and compare it to recent experiments at SLAC, MAMI and CERN with electrons and negative pions in the energy range from 0.855 to 150 GeV in Si crystals. We show that Lindhard reversibility rule provides sufficient basis for quantitative understanding of these experiments.

Axially symmetrical stresses measurement in the cylindrical tube using DIC with hole-drilling

Science.gov (United States)

Ma, Yinji; Yao, Xuefeng; Zhang, Danwen

2015-03-01

In this paper, a new method combining the digital image correlation (DIC) with the hole-drilling technology to characterize the axially symmetrical stresses of the cylindrical tube is developed. First, the theoretical expressions of the axially symmetrical stresses in the cylindrical tube are derived based on the displacement or strain fields before and after hole-drilling. Second, the release of the axially symmetrical stresses for the cylindrical tube caused by hole-drilling is simulated by the finite element method (FEM), which indicates that the axially symmetrical stresses of the cylindrical tube calculated by the cylindrical solution is more accuracy than that for traditionally planar solution. Finally, both the speckle image information and the displacement field of the cylindrical tube before and after hole-drilling are extracted by combining the DIC with the hole-drilling technology, then the axially symmetrical loading induced stresses of the cylindrical tube are obtained, which agree well with the results from the strain gauge method.

Introduction to gauge theories

International Nuclear Information System (INIS)

Wit, B. de

1983-01-01

In these lectures we present the key ingredients of theories with local gauge invariance. We introduce gauge invariance as a starting point for the construction of a certain class of field theories, both for abelian and nonabelian gauge groups. General implications of gauge invariance are discussed, and we outline in detail how gauge fields can acquire masses in a spontaneous fashion. (orig./HSI)

Gauge field models

International Nuclear Information System (INIS)

Becchi, C.; Rouet, A.; Stora, R.

1975-10-01

Stora's analysis is continued in discussing the nonabelian (Yang-Mills) gauge field models (G.F.M.). The gauge independence of the physical scattering operator is discussed in some details and the connection between its unitary and the Slavnov symmetry outlined. Only the models involving semisimple gauge groups are considered. This greatly simplifies the analysis of the possible quantum corrections to the Quantum Action Principle which is reduced to the study of the cohomology group of the Lie algebra characterizing the gauge theory. The discussion is at the classical level for the algebraic properties of the SU(2) Higgs-Kibble-Englert-Brout-Faddeev-Popov lagrangian and its invariance under Slavnov identity transformations is exhibited. The renormalization of the Slavnov identity in the G.M.F. involving semisimple gauge groups is studied. The unitary and gauge independence of the physical S operator in the SU(2) H.K. model is dealt with [fr

Zero energy gauge fields and the phases of a gauge theory

International Nuclear Information System (INIS)

Guendelman, E.I.

1990-01-01

A new approach to the definition of the phases of a Poincare invariant gauge theory is developed. It is based on the role of gauge transformations that change the asymptotic value of the gauge fields from zero to a constant. In the context of theories without Higgs fields, this symmetry can be spontaneously broken when the gauge fields are massless particles, explicitly broken when the gauge fields develop a mass. Finally, the vacuum can be invariant under this transformation, this last case can be achieved when the theory has a violent infrared behavior, which in some theories can be connected to a confinement mechanism

Total spectrum of photon emission by an ultra-relativistic positron channelling in a periodically bent crystal

International Nuclear Information System (INIS)

Krause, W.; Korol, A.V.; Department of Physics, St Petersburg State Maritime Technical University, Leninskii prospect 101, St Petersburg 198262; Solov'yov, A.V.; AF Ioffe Physical-Technical Institute of the Academy of Sciences of Russia, Polytechnicheskaya 26, St Petersburg 194021; Greiner, W.

2000-01-01

We present the results of numerical calculations of the channelling and undulator radiation generated by ultra-relativistic positron channelling along a crystal plane, which is periodically bent. The bending might be due to either the propagation of a transverse acoustic wave through the crystal, or the static strain as it occurs in superlattices. The periodically bent crystal serves as an undulator. We investigate the dependence of the intensities of both the ordinary channelling and the undulator radiations on the parameters of the periodically bent channel with simultaneous account for the de-channelling effect of the positrons. We demonstrate that there is a range of parameters in which the undulator radiation dominates over the channelling one and the characteristic frequencies of both types of radiation are well separated. This result is important, because the undulator radiation can be used to create a tunable source of x-ray and γ-radiation. (author). Letter-to-the-editor

A study on the pressure ripple characteristics in a bent-axis type oil hydraulic piston pump

International Nuclear Information System (INIS)

Cho, Ihn Sung; Jung, Jae Youn

2013-01-01

To improve the performance of a bent-axis type axial piston pump driven by tapered pistons, it is necessary to know the pressure ripple characteristics. The purpose of this paper is to understand the effect on the pressure ripple characteristics, and to predict by comparing experimental and theoretical analysis results. The simulation model of a bent-axis type axial piston pump is developed in the AMESim environment using the geometrical dimension, and the driving mechanism of the piston pump, such as the stroke of pump, the velocity of piston, the instantaneous volumetric flow, the overlap area of valve plate opening to cylinder bore, the angle of notch, and so on. The results show that theoretical analysis results of the bent-axis type axial piston pump by using the AMESim approximate the pressure ripple characteristic of the test pump, and through this, simulations can be obtained that predict the performance characteristics of a bentaxis type axial piston pump.

Gauge fixing conditions for the SU(3) gauge theory

International Nuclear Information System (INIS)

Ragiadakos, Ch.; Viswanathan, K.S.

1979-01-01

SU(3) gauge theory is quantized in the temporal gauge A 0 =0. Gauge fixing conditions are imposed completely on the electric field components, conjugate to the vector potential Ssub(i) that belongs to the subalgebra SO(3) of SU(3). The generating functional in terms of the independent variables is derived. It is ghost-free and may be regarded as a theory of (non-relativistic) spin-0, 1, 2, and 3 fields. (Auth.)

The bent crystal diffraction spectrometer at the BR2 reactor in Mol

Science.gov (United States)

Kaerts, E.; Jacobs, L.; Vandenput, G.; Van Assche, P. H. M.

1988-05-01

The DuMond-type bent crystal diffraction spectrometer installed at the BR2 reactor in Mol is presented. The spectrometer is mainly designed to study nuclear γ-transitions following thermal neutron capture. It covers the energy interval 25 ≦ Eγ ≦ 1500 keV. Instead of the traditionally used quartz crystals, a highly perfect silicium crystal is chosen as analysing crystal. Diffraction occurs from the (220) plane. The "quasi-mosaic" width, introduced by bending the crystal, is as small as 0.2″. The integrated reflecting power R of the bent crystal stays constant up to 1.5 MeV in first, 680 keV in second and 300 keV in third diffraction order. For higher photon energies, only an E-1 energy dependence is observed in second and third diffraction order. Consequently, besides improving the energy resolution, the use of these silicium crystals substantially increases the spectrometer efficiency and extends the high energy limit of bent crystal diffraction spectrometers. The diffraction angles are measured with a symmetrical interferometer system which covers an angular range of -6° to +6° with a precision of about 0.01″. Minimum diffraction line widths of 0.9″ have been measured, corresponding to an energy resolution ΔE = 1.35 × 10 -6E2n-1 keV -1. The dominant contribution to the observed line widths arises from the finite extent of the source.

THE TOPOLOGY OF CANONICAL FLUX TUBES IN FLARED JET GEOMETRY

Energy Technology Data Exchange (ETDEWEB)

Lavine, Eric Sander; You, Setthivoine, E-mail: Slavine2@uw.edu, E-mail: syou@aa.washington.edu [University of Washington, 4000 15th Street, NE Aeronautics and Astronautics 211 Guggenheim Hall, Box 352400, Seattle, WA 98195 (United States)

2017-01-20

Magnetized plasma jets are generally modeled as magnetic flux tubes filled with flowing plasma governed by magnetohydrodynamics (MHD). We outline here a more fundamental approach based on flux tubes of canonical vorticity, where canonical vorticity is defined as the circulation of the species’ canonical momentum. This approach extends the concept of magnetic flux tube evolution to include the effects of finite particle momentum and enables visualization of the topology of plasma jets in regimes beyond MHD. A flared, current-carrying magnetic flux tube in an ion-electron plasma with finite ion momentum is thus equivalent to either a pair of electron and ion flow flux tubes, a pair of electron and ion canonical momentum flux tubes, or a pair of electron and ion canonical vorticity flux tubes. We examine the morphology of all these flux tubes for increasing electrical currents, different radial current profiles, different electron Mach numbers, and a fixed, flared, axisymmetric magnetic geometry. Calculations of gauge-invariant relative canonical helicities track the evolution of magnetic, cross, and kinetic helicities in the system, and show that ion flow fields can unwind to compensate for an increasing magnetic twist. The results demonstrate that including a species’ finite momentum can result in a very long collimated canonical vorticity flux tube even if the magnetic flux tube is flared. With finite momentum, particle density gradients must be normal to canonical vorticities, not to magnetic fields, so observations of collimated astrophysical jets could be images of canonical vorticity flux tubes instead of magnetic flux tubes.

Residual gauge invariance of Hamiltonian lattice gauge theories

International Nuclear Information System (INIS)

Ryang, S.; Saito, T.; Shigemoto, K.

1984-01-01

The time-independent residual gauge invariance of Hamiltonian lattice gauge theories is considered. Eigenvalues and eigenfunctions of the unperturbed Hamiltonian are found in terms of Gegengauer's polynomials. Physical states which satisfy the subsidiary condition corresponding to Gauss' law are constructed systematically. (orig.)

Regularization of the light-cone gauge gluon propagator singularities using sub-gauge conditions

Energy Technology Data Exchange (ETDEWEB)

Chirilli, Giovanni A.; Kovchegov, Yuri V.; Wertepny, Douglas E. [Department of Physics, The Ohio State University,191 W Woodruff Ave, Columbus, OH 43210 (United States)

2015-12-21

Perturbative QCD calculations in the light-cone gauge have long suffered from the ambiguity associated with the regularization of the poles in the gluon propagator. In this work we study sub-gauge conditions within the light-cone gauge corresponding to several known ways of regulating the gluon propagator. Using the functional integral calculation of the gluon propagator, we rederive the known sub-gauge conditions for the θ-function gauges and identify the sub-gauge condition for the principal value (PV) regularization of the gluon propagator’s light-cone poles. The obtained sub-gauge condition for the PV case is further verified by a sample calculation of the classical Yang-Mills field of two collinear ultrarelativistic point color charges. Our method does not allow one to construct a sub-gauge condition corresponding to the well-known Mandelstam-Leibbrandt prescription for regulating the gluon propagator poles.

Interactions between posture and locomotion: motor patterns in humans walking with bent posture versus erect posture.

Science.gov (United States)

Grasso, R; Zago, M; Lacquaniti, F

2000-01-01

Human erect locomotion is unique among living primates. Evolution selected specific biomechanical features that make human locomotion mechanically efficient. These features are matched by the motor patterns generated in the CNS. What happens when humans walk with bent postures? Are normal motor patterns of erect locomotion maintained or completely reorganized? Five healthy volunteers walked straight and forward at different speeds in three different postures (regular, knee-flexed, and knee- and trunk-flexed) while their motion, ground reaction forces, and electromyographic (EMG) activity were recorded. The three postures imply large differences in the position of the center of body mass relative to the body segments. The elevation angles of the trunk, pelvis, and lower limb segments relative to the vertical in the sagittal plane, the ground reaction forces and the rectified EMGs were analyzed over the gait cycle. The waveforms of the elevation angles along the gait cycle remained essentially unchanged irrespective of the adopted postures. The first two harmonics of these kinematic waveforms explain >95% of their variance. The phase shift but not the amplitude ratio between the first harmonic of the elevation angle waveforms of adjacent pairs was affected systematically by changes in posture. Thigh, shank, and foot angles covaried close to a plane in all conditions, but the plane orientation was systematically different in bent versus erect locomotion. This was explained by the changes in the temporal coupling among the three segments. For walking speeds >1 m s(-1), the plane orientation of bent locomotion indicates a much lower mechanical efficiency relative to erect locomotion. Ground reaction forces differed prominently in bent versus erect posture displaying characteristics intermediate between those typical of walking and those of running. Mean EMG activity was greater in bent postures for all recorded muscles independent of the functional role. The waveforms

Ram pressure statistics for bent tail radio galaxies

CSIR Research Space (South Africa)

Mguda, Z

2015-01-01

Full Text Available ), Department of Astronomy, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa 2South African Astronomical Observatory (SAAO), PO Box 9, 7935 Observatory, Cape Town, South Africa 3Department of Physics, University of Witwatersrand... Published by Oxford University Press on behalf of the Royal Astronomical Society at South A frican A stronom ical O bservatory on D ecem ber 18, 2014 http://m nras.oxfordjournals.org/ D ow nloaded from Statistics for bent radio sources 3311 are left for a...

Ultrasonic wall thickness gauging for ferritic steam generator tubing as an in-service inspection tool

International Nuclear Information System (INIS)

Haesen, W.M.J.; Tromp, Th.J.

1980-01-01

In-service inspection of LWR steam generators is more or less a standard routine operation. The situation can be very different for LMFBRs. For the SNR 300 (Kalkar Power Station) the situation is different because the steam generators have ferritic tubing. The tube walls are comparatively thick, 2 to 4.5 mm. During inservice examinations the steam generators will be drained on both sides, however on the sodium side a sodium film will be present. Furthermore the SNR 300 will have two types of steam generator. A straight tube design and a helical coil design will be used. Both types consist of a evaporator and superheater. The steam generators are of course not radioactive. It is obvious that in this case the eddy current (EC) technique is not an enviable inservice inspection tool. Basically EC is a surface flaw detection technique. Only the saturation magnetisation method will improve the EC technique sufficiently for ferritic material. However the 'in bore examination' with the saturation technique was, in case of the SNR 300 steam generator tubing, considered impossible since the inner diameters are fairly small. Furthermore sodium traces may influence the EC method. Although multifrequency methods can solve this problem, EC is not considered as a useful tool for examining ferritic tubing. Another method is to employ the 'stray flux' method which is under development with the TNO organization in Holland. The EC and stray flux method do have one drawback, these methods do not detect gradual changes in wall thickness. Ultrasonic examinations will be used in the SNR 300 as the main inspection tool for the steam generators. In this paper the reasons why ultrasonic examination was selected are explained. The results of the development work on this subject are discussed

Nonlocal gauge theories

International Nuclear Information System (INIS)

Krasnikov, N.V.

1987-01-01

Nonlocal gauge theories including gravity are considered. It is shown that the introduction of the additional nonlocal interaction makes γ 5 -anomalous theories meaningful. The introduction of such interaction leads to macrocausal unitary theory, which describes the interaction of massive vector fields with fermion fields. It is shown that nonlocal gauge theories with nonlocal scale Λ nl ≤(1-10) TeV can solve the gauge hierarchy problem. An example of nonlinear grand unified gauge model in which topologically nontrivial finite energy monopole solutions are absent is found

Interference effects in Bragg-case synchrotron section topography of elastically bent silicon implanted crystals

International Nuclear Information System (INIS)

Wierzchowski, W.; Wieteska, K.; Graeff, W.

1997-01-01

White-beam synchrotron section topography was applied to a silicon crystal implanted with 4.8 MeV α-particles elastically bent with the radius of curvature close to 100 m. A number of section patterns corresponding to different reflections was analysed. It was found that the section pattern in the bent sample was drastically different from those observed in a flat sample. The difference consists in the occurrence of the sets of additional interference fringes covering a long distance up to several millimetres behind the main diffraction maximum. It was possible to reproduce some characteristic features of the fringes both in the implanted and non-implanted region by numerical integration of the Takagi-Taupin equation

Time-of-flight neutron Bragg-edge transmission imaging of microstructures in bent steel plates

Energy Technology Data Exchange (ETDEWEB)

Su, Yuhua, E-mail: yuhua.su@j-parc.jp [J-PARC Center, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Ibaraki 319-1195 (Japan); Oikawa, Kenichi; Harjo, Stefanus; Shinohara, Takenao; Kai, Tetsuya; Harada, Masahide; Hiroi, Kosuke [J-PARC Center, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Ibaraki 319-1195 (Japan); Zhang, Shuoyuan; Parker, Joseph Don [Neutron R& D Division, CROSS-Tokai, 162-1 Shirakata, Tokai, Ibaraki 319-1106 (Japan); Sato, Hirotaka [Faculty of Engineering, Hokkaido University, Sapporo 060-8628 (Japan); Shiota, Yoshinori; Kiyanagi, Yoshiaki [Graduate School of Engineering, Nagoya University, Nagoya, Aichi 464-8603 (Japan); Tomota, Yo [Research Center for Strategic Materials, National Institute for Materials Science, Tsukuba 305-0047 (Japan)

2016-10-15

Neutron Bragg-edge transmission imaging makes it possible to quantitatively visualize the two-dimensional distribution of microstructure within a sample. In order to examine its application to engineering products, time-of-flight Bragg-edge transmission imaging experiments using a pulsed neutron source were performed for plastically bent plates composed of a ferritic steel and a duplex stainless steel. The non-homogeneous microstructure distributions, such as texture, crystalline size, phase volume fraction and residual elastic strain, were evaluated for the cross sections of the bent plates. The obtained results were compared with those by neutron diffraction and electron back scatter diffraction, showing that the Bragg-edge transmission imaging is powerful for engineering use.

Straight proximal humeral nails are surrounded by more bone stock in comparison to bent nails in an experimental cadaveric study.

Science.gov (United States)

Günther, Christian Max; Müller, Peter Ernst; Mutschler, Wolf; Sprecher, Christoph Martin; Milz, Stefan; Braunstein, Volker

2014-01-01

In the management of proximal humeral fractures intramedullary implants with bent and straight shape of the proximal part of nail are available. Based on data from previous studies on bone distribution in the humeral head, we hypothesized, that higher densities might exist in the bone stock surrounding straight nails in comparison to their angulated counterparts. With a known positive correlation between bone density and mechanical stability, this could indicate potentially higher rigidity of osteosyntheses done with straight implants. We performed high resolution peripheral quantitative computed tomographies of the potential straight and bent implant bearing regions of 27 cadaveric proximal humeri. The acquired data were analyzed for differences between straight and bent Volumes of Interest as well as intra- and interindividual bone stock distribution. For both straight and bent volumes of interest a considerably declining bone mineral density was found in craniocaudal direction. Mean densities of bent volumes were significantly lower in comparison to their corresponding straight counterparts (p straight shaped implants can be assumed. Since we found a rapid decrease of bone density in cranio-caudal direction, intramedullary implants should be anchored as proximally in the subcortical area as possible to minimize the risk of displacement or cutout. The high correlation between the Volumes of Interest of the corresponding right and left sides could aid in preoperative planning when considering an intra- or extramedullary approach.

Harada–Tsutsui gauge recovery procedure: From Abelian gauge anomalies to the Stueckelberg mechanism

International Nuclear Information System (INIS)

Lima, Gabriel Di Lemos Santiago

2014-01-01

Revisiting a path-integral procedure developed by Harada and Tsutsui for recovering gauge invariance from anomalous effective actions, it is shown that there are two ways to achieve gauge symmetry: one already presented by the authors, which is shown to preserve the anomaly in the sense of standard current conservation law, and another one which is anomaly-free, preserving current conservation. It is also shown that the application of the Harada–Tsutsui technique to other models which are not anomalous but do not exhibit gauge invariance allows the identification of the gauge invariant formulation of the Proca model, also done by the referred authors, with the Stueckelberg model, leading to the interpretation of the gauge invariant map as a generalization of the Stueckelberg mechanism. -- Highlights: • A gauge restoration technique from Abelian anomalous models is discussed. • It is shown that there is another way that leads to gauge symmetry restoration from such technique. • It is shown that the first gauge restoration preserves the anomaly, while the proposed second one is free from anomalies. • It is shown that the proposed gauge symmetry restoration can be identified with the Stueckelberg mechanism

Harada–Tsutsui gauge recovery procedure: From Abelian gauge anomalies to the Stueckelberg mechanism

Energy Technology Data Exchange (ETDEWEB)

Lima, Gabriel Di Lemos Santiago, E-mail: gabriellemos3@hotmail.com

2014-02-15

Revisiting a path-integral procedure developed by Harada and Tsutsui for recovering gauge invariance from anomalous effective actions, it is shown that there are two ways to achieve gauge symmetry: one already presented by the authors, which is shown to preserve the anomaly in the sense of standard current conservation law, and another one which is anomaly-free, preserving current conservation. It is also shown that the application of the Harada–Tsutsui technique to other models which are not anomalous but do not exhibit gauge invariance allows the identification of the gauge invariant formulation of the Proca model, also done by the referred authors, with the Stueckelberg model, leading to the interpretation of the gauge invariant map as a generalization of the Stueckelberg mechanism. -- Highlights: • A gauge restoration technique from Abelian anomalous models is discussed. • It is shown that there is another way that leads to gauge symmetry restoration from such technique. • It is shown that the first gauge restoration preserves the anomaly, while the proposed second one is free from anomalies. • It is shown that the proposed gauge symmetry restoration can be identified with the Stueckelberg mechanism.

Bent dark soliton dynamics in two spatial dimensions beyond the mean field approximation

Science.gov (United States)

Mistakidis, Simeon; Katsimiga, Garyfallia; Koutentakis, Georgios; Kevrekidis, Panagiotis; Schmelcher, Peter; Theory Group of Fundamental Processes in Quantum Physics Team

2017-04-01

The dynamics of a bented dark soliton embedded in two spatial dimensions beyond the mean-field approximation is explored. We examine the case of a single bented dark soliton comparing the mean-field approximation to a correlated approach that involves multiple orbitals. Fragmentation is generally present and significantly affects the dynamics, especially in the case of stronger interparticle interactions and in that of lower atom numbers. It is shown that the presence of fragmentation allows for the appearance of solitonic and vortex structures in the higher-orbital dynamics. In particular, a variety of excitations including dark solitons in multiple orbitals and vortex-antidark complexes is observed to arise spontaneously within the beyond mean-field dynamics. Deutsche Forschungsgemeinschaft (DFG) in the framework of the SFB 925 ``Light induced dynamics and control of correlated quantum systems''.

Quantum and classical gauge symmetries

International Nuclear Information System (INIS)

Fujikawa, Kazuo; Terashima, Hiroaki

2001-01-01

The use of the mass term of the gauge field as a gauge fixing term, which was discussed by Zwanziger, Parrinello and Jona-Lasinio in a large mass limit, is related to the non-linear gauge by Dirac and Nambu. We have recently shown that this use of the mass term as a gauge fixing term is in fact identical to the conventional local Faddeev-Popov formula without taking a large mass limit, if one takes into account the variation of the gauge field along the entire gauge orbit. This suggests that the classical massive vector theory, for example, could be re-interpreted as a gauge invariant theory with a gauge fixing term added in suitably quantized theory. As for massive gauge particles, the Higgs mechanics, where the mass term is gauge invariant, has a more intrinsic meaning. We comment on several implications of this observation. (author)

Validation of the Lanzarote Tide Gauges system designed at the Royal Observatory of Belgium

Science.gov (United States)

van Ruymbeke, Michel; Dumont, Philippe; Seknik, Matej

2017-04-01

A series of tide gauges was set-up in a very favorable site located inside a lava tube plunging in the Atlantic ocean. The damping of waves motion is dramaticaly large, allowing to observe very tight modulations of the sea level. The gauges are based on the EDAS interface connected to a capacitor variying with the level of the sea . Filtering is gained by counting of frequency modulated signal during a one minute interval The scale factor is defined by comparizon of the output signals of sensors and reading the water level at different time. We evaluate the performance of our design by analysing the long series of records at disposal. The analysis is based on a stacking approach to extract components for periodicities existing in the spectrum of sea tides . Concordance of the results between the three gauges recording simultaneously the same signal confirms applicability of our design in such environment. After de-tiding application, the residuals signals are correlated to various physical parameters which could contribute to the understanding of the involved geophysical process.

Numerical Prediction of Springback Shape of Severely Bent Sheet Metal

International Nuclear Information System (INIS)

Iwata, Noritoshi; Murata, Atsunobu; Yogo, Yasuhiro; Tsutamori, Hideo; Niihara, Masatomo; Ishikura, Hiroshi; Umezu, Yasuyoshi

2007-01-01

In the sheet metal forming simulation, the shell element widely used is assumed as a plane stress state based on the Mindlin-Reissner theory. Numerical prediction with the conventional shell element is not accurate when the bending radius is small compared to the sheet thickness. The main reason is because the strain and stress formulation of the conventional shell element does not fit the actual phenomenon. In order to predict precisely the springback of a bent sheet with a severe bend, a measurement method for through-thickness strain has been proposed. The strain was formulated based on measurement results and calculation results from solid element. Through-thickness stress distribution was formulated based on the equilibrium. The proposed shell element based on the formulations was newly introduced into the FEM code. The accuracy of this method's prediction of the springback shape of two bent processes has been confirmed. As a result, it was found that the springback shape even in severe bending can be predicted with high accuracy. Moreover, the calculation time in the proposed shell element is about twice that in the conventional shell element, and has been shortened to about 1/20 compared to a solid element

FIRST Bent-Double Radio Sources: Tracers of High-Redshift Clusters

International Nuclear Information System (INIS)

Blanton, E. L.; Gregg, M. D.; Helfand, D. J.; Becker, R. H.; White, R. L.

2000-01-01

Bent-double radio sources can act as tracers for clusters of galaxies. We present imaging and spectroscopic observations of the environments surrounding 10 of these sources (most of them wide-angle tails [WATs]) selected from the VLA FIRST survey. Our results reveal a previously unknown cluster associated with eight of the radio sources with redshifts in the range 0.33< z<0.85; furthermore, we cannot rule out that the other two bent doubles may be associated with clusters at higher redshift. Richness measurements indicate that these clusters are typical of the majority of those found in the Abell catalog, with a range of Abell richness classes from 0 to 2. The line-of-sight velocity dispersions are very different from cluster to cluster, ranging from approximately 300 to 1100 km s-1. At the upper end of these intervals, we may be sampling some of the highest redshift massive clusters known. Alternatively, the large velocity dispersions measured in some of the clusters may indicate that they are merging systems with significant substructure, consistent with recent ideas concerning WAT formation (Burns et al.). (c) 2000 The American Astronomical Society

Bent and linear Uranium(IV) metallocenes with terminal and bridging cyanide ligands

International Nuclear Information System (INIS)

Maynadie, J.; Berthet, J.C.; Thuery, P.; Ephritikhine, M.

2007-01-01

Treatment of Cp 2 * UI 2 with KCN in thf led to the formation of Cp 2 * U(CN) 2 (2), which further reacted with NR 4 CN to give [Cp 2 * U(CN) 3 ][ NR 4 ] (R = Et, 3; R = n Bu, 3') and [Cp 2 * U(CN) 5 ][NR 4 ] 3 (R = Et, 4; R n Bu, 4'). While the tri-cyanide 3' adopts the familiar bent sandwich configuration, the penta-cyanide 4 is, after the [Cp 2 * U(NCMe) 5 ] 2+ cation, the second example of a linear metallocene resulting from complete saturation of the equatorial girdle. Compound 3' was also obtained by oxidation of the trivalent compound [Cp 2 * U(CN) 3 ][N n Bu 4 ] 2 ; the rapid and reversible electron transfer between the U(III) and U(IV) complexes was revealed by 1 H NMR spectroscopy. The NMR spectra also revealed that 4 is partially dissociated in thf into 3, providing the first example of an equilibrating couple of bent and linear metallocenes [K = 4.24(4) * 10 -5 at 25 C, ΔH = 199(6) kJ mol -1 , and ΔS = 586(20) J mol -1 K -1 ]. The trinuclear compound [Cp 2 * UCl 2 (μ-CN)] 2 Mg(thf) 4 (1) and the 2D polymeric complex [Cp 2 * U(dmf) 3 -(μ-NC) 2 (AgI) 2 ] n (5), which were obtained during initial attempts on the synthesis of 2-4 and uranium- (V) derivatives, exhibit a bent and linear sandwich structure, respectively. (authors)

Topologically massive gauge theories and their dual factorized gauge-invariant formulation

International Nuclear Information System (INIS)

Bertrand, Bruno; Govaerts, Jan

2007-01-01

There exists a well-known duality between the Maxwell-Chern-Simons theory and the 'self-dual' massive model in (2 + 1) dimensions. This dual description may be extended to topologically massive gauge theories (TMGT) for forms of arbitrary rank and in any dimension. This communication introduces the construction of this type of duality through a reparametrization of the 'master' theory action. The dual action thereby obtained preserves the full gauge symmetry structure of the original theory. Furthermore, the dual action is factorized into a propagating sector of massive gauge-invariant variables and a decoupled sector of gauge-variant variables defining a pure topological field theory. Combining the results obtained within the Lagrangian and Hamiltonian formulations, a completed structure for a gauge-invariant dual factorization of TMGT is thus achieved. (fast track communication)

Global aspects of gauge anomalies

International Nuclear Information System (INIS)

Zhang, H.

1988-01-01

This dissertation discusses the global aspects of gauge anomalies in even dimensions. After a very brief description of local gauge anomalies, the possible global gauge anomalies for various gauge theories are discussed using homotopy theory. One of the main results obtained in a general formula for the SU(n - k) global gauge anomaly coefficient in arbitrary 2n dimensions. The result is expressed in terms of the James number of the Stiefel manifold SU(n + 1)/SU(n - k) and the generalized Dynkin indices. From this, the possibilities of SU(n), SU(n - 1), and SU(2) global gauge anomalies in arbitrary 2n dimensions have been determined. We have also determined the possibilities of global gauge anomalies for the gauge groups SP(2N) and SO(N) in certain general dimensions, as well as for the exceptional gauge groups in specific dimensions. Moreover, several general propositions are formulated and proved which are very useful in the study of global gauge anomalies

Gauge symmetry from decoupling

Directory of Open Access Journals (Sweden)

C. Wetterich

2017-02-01

Full Text Available Gauge symmetries emerge from a redundant description of the effective action for light degrees of freedom after the decoupling of heavy modes. This redundant description avoids the use of explicit constraints in configuration space. For non-linear constraints the gauge symmetries are non-linear. In a quantum field theory setting the gauge symmetries are local and can describe Yang–Mills theories or quantum gravity. We formulate gauge invariant fields that correspond to the non-linear light degrees of freedom. In the context of functional renormalization gauge symmetries can emerge if the flow generates or preserves large mass-like terms for the heavy degrees of freedom. They correspond to a particular form of gauge fixing terms in quantum field theories.

Flexible bent rod model with a saturating induced dipole moment to study the electric linear dichroism of DNA fragments

Directory of Open Access Journals (Sweden)

Jorge A. Bertolotto

2016-06-01

Full Text Available In the present work we make a theoretical study of the steady state electric linear dichroism of DNA fragments in aqueous solution. The here developed theoretical approach considers a flexible bent rod model with a saturating induced dipole moment. The electric polarizability tensor of bent DNA fragments is calculated considering a phenomenological model which theoretical and experimental backgroung is presented here. The model has into account the electric polarizability longitudinal and transversal to the macroion. Molecular flexibility is described using an elastic potential. We consider DNA fragments originally bent with bending fluctuations around an average bending angle. The induced dipole moment is supposed constant once the electric field strength grows up at critical value. To calculate the reduced electric linear dichroism we determine the optical factor considering the basis of the bent DNA perpendicular to the molecular axis. The orientational distribution function has into account the anisotropic electric properties and the molecule flexibility. We applied the present theoretical background to fit electric dichroism experimental data of DNA fragments reported in the bibliography in a wide range of molecular weight and electric field. From these fits, values of DNA physical properties are estimated. We compare and discuss the results here obtained with the theoretical and experimental data presented by other authors. The original contributions of this work are: the inclusion of the transversal electric polarizability saturating with the electric field, the description of the electric properties with an electric polarizability tensor dependant on the bending angle and the use of an arc model originally bent.

Flexible bent rod model with a saturating induced dipole moment to study the electric linear dichroism of DNA fragments

Science.gov (United States)

Bertolotto, Jorge A.; Umazano, Juan P.

2016-06-01

In the present work we make a theoretical study of the steady state electric linear dichroism of DNA fragments in aqueous solution. The here developed theoretical approach considers a flexible bent rod model with a saturating induced dipole moment. The electric polarizability tensor of bent DNA fragments is calculated considering a phenomenological model which theoretical and experimental backgroung is presented here. The model has into account the electric polarizability longitudinal and transversal to the macroion. Molecular flexibility is described using an elastic potential. We consider DNA fragments originally bent with bending fluctuations around an average bending angle. The induced dipole moment is supposed constant once the electric field strength grows up at critical value. To calculate the reduced electric linear dichroism we determine the optical factor considering the basis of the bent DNA perpendicular to the molecular axis. The orientational distribution function has into account the anisotropic electric properties and the molecule flexibility. We applied the present theoretical background to fit electric dichroism experimental data of DNA fragments reported in the bibliography in a wide range of molecular weight and electric field. From these fits, values of DNA physical properties are estimated. We compare and discuss the results here obtained with the theoretical and experimental data presented by other authors. The original contributions of this work are: the inclusion of the transversal electric polarizability saturating with the electric field, the description of the electric properties with an electric polarizability tensor dependant on the bending angle and the use of an arc model originally bent.

Extraction from TEV-range accelerators using bent crystal channeling

International Nuclear Information System (INIS)

Carrigan, R.A. Jr.; Jackson, G.; Murphy, C.T.; Newberger, B.

1993-01-01

Plans and first results from Fermilab Experiment 853 are presented. E853 is an experiment to test the feasibility and efficiency of extracting a low-intensity beam from the halo of the Tevatron using channeling in a bent silicon crystal. The motivation of the experiment is to apply crystal extraction to trans-TeV accelerators like the SSC. Channeling developments related to crystal extraction and some early results from accelerator studies at the Tevatron are presented

Stereotactic core biopsy: Comparison of 11 gauge with 8 gauge vacuum assisted breast biopsy

Energy Technology Data Exchange (ETDEWEB)

Venkataraman, Shambhavi, E-mail: svenkata@bidmc.harvard.edu [Department of Radiology, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215 (United States); Dialani, Vandana [Department of Radiology, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215 (United States); Gilmore, Hannah L. [Department of Pathology, UH Case Medical Center, 11100 Euclid Ave, Cleveland, OH 44106 (United States); Mehta, Tejas S. [Department of Radiology, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215 (United States)

2012-10-15

Purpose: The compare the performance and ability to obtain a correct diagnosis on needle biopsy between 11 gauge and 8 gauge vacuum assisted biopsy devices. Materials and methods: Hospital records of all consecutive stereotactic core biopsies performed over five years were retrospectively reviewed in compliance Health Insurance Portability and Accountability Act (HIPPA) policy and with approval from the hospital institutional review board (IRB). Pathology from core biopsy was compared with surgical pathology and/or imaging follow-up. A histological underestimation was defined if the surgical excision yielded a higher grade on pathology which changed management. Results: 828 needle core biopsies (47.5%, 393/828 with 11 gauge and 52.5%, 435/828 with 8 gauge) yielded 471 benign, 153 high risk and 204 malignant lesions. 30/193 (15.5%) 11 gauge lesions and 16/185 (8.6%) 8 gauge lesions demonstrated higher grade pathology on surgical excision. The difference in the rates of the number of correct diagnoses on core needle biopsy between 11 gauge (363/393, 92.4%) and 8 gauge (419/435, 96.3%) based on either surgical or clinical/imaging follow up and the difference in the number of discordant benign core biopsies between 11 (17/217, 7.8%) and 8 gauge (4/254, 1.6%) necessitating a surgical biopsy was significant (P = 0.013; P = 0.001). Although there were more underestimations with the 11 gauge (25/193, 13.0%) than 8 gauge (15/185, 8.1%) needle, this was not significant. Conclusion: Our study demonstrates improved performance and increased diagnostic ability of 8 gauge needle over 11 gauge in obtaining a correct diagnosis on needle biopsy.

Extended pure Yang-Mills gauge theories with scalar and tensor gauge fields

International Nuclear Information System (INIS)

Gabrielli, E.

1991-01-01

The usual abelian gauge theory is extended to an interacting Yang-Mills-like theory containing vector, scalar and tensor gauge fields. These gauge fields are seen as components along the Clifford algebra basis of a gauge vector-spinorial field. Scalar fields φ naturally coupled to vector and tensor fields have been found, leading to a natural φ 4 coupling in the lagrangian. The full expression of the lagrangian for the euclidean version of the theory is given. (orig.)

Intrinsic bent DNA sites in the chromosomal replication origin of Xylella fastidiosa 9a5c

Directory of Open Access Journals (Sweden)

F. Gimenes

2008-04-01

Full Text Available The features of the nucleotide sequences in both replication and promoter regions have been investigated in many organisms. Intrinsically bent DNA sites associated with transcription have been described in several prokaryotic organisms. The aim of the present study was to investigate intrinsic bent DNA sites in the segment that holds the chromosomal replication origin, oriC, of Xylella fastidiosa 9a5c. Electrophoretic behavior analyses, as well as in silico analyses of both the 2-D projection and helical parameters, were performed. The chromosomal segment analyzed contains the initial sequence of the rpmH gene, an intergenic region, the dnaA gene, the oriC sequence, and the 5' partial sequence of the dnaN gene. The analysis revealed fragments with reduced electrophoretic mobility, which indicates the presence of curved DNA segments. The analysis of the helical parameter ENDS ratio revealed three bent DNA sites (b1, b2, and b3 located in the rpmH-dnaA intergenic region, the dnaA gene, and the oriC 5' end, respectively. The chromosomal segment of X. fastidiosa analyzed here is rich in phased AT tracts and in CAnT motifs. The 2-D projection indicated a segment whose structure was determined by the cumulative effect of all bent DNA sites. Further, the in silico analysis of the three different bacterial oriC sequences indicated similar negative roll and twist >34.00° values. The DnaA box sequences, and other motifs in them, may be associated with the intrinsic DNA curvature.

Nambu–Poisson gauge theory

Energy Technology Data Exchange (ETDEWEB)

Jurčo, Branislav, E-mail: jurco@karlin.mff.cuni.cz [Charles University in Prague, Faculty of Mathematics and Physics, Mathematical Institute, Prague 186 75 (Czech Republic); Schupp, Peter, E-mail: p.schupp@jacobs-university.de [Jacobs University Bremen, 28759 Bremen (Germany); Vysoký, Jan, E-mail: vysokjan@fjfi.cvut.cz [Jacobs University Bremen, 28759 Bremen (Germany); Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering, Prague 115 19 (Czech Republic)

2014-06-02

We generalize noncommutative gauge theory using Nambu–Poisson structures to obtain a new type of gauge theory with higher brackets and gauge fields. The approach is based on covariant coordinates and higher versions of the Seiberg–Witten map. We construct a covariant Nambu–Poisson gauge theory action, give its first order expansion in the Nambu–Poisson tensor and relate it to a Nambu–Poisson matrix model.

Nambu–Poisson gauge theory

International Nuclear Information System (INIS)

Jurčo, Branislav; Schupp, Peter; Vysoký, Jan

2014-01-01

We generalize noncommutative gauge theory using Nambu–Poisson structures to obtain a new type of gauge theory with higher brackets and gauge fields. The approach is based on covariant coordinates and higher versions of the Seiberg–Witten map. We construct a covariant Nambu–Poisson gauge theory action, give its first order expansion in the Nambu–Poisson tensor and relate it to a Nambu–Poisson matrix model.

Self-dual gauge theories

International Nuclear Information System (INIS)

Zet, G.

2002-01-01

The self-duality equations are important in gauge theories because they show the connection between gauge models with internal symmetry groups and gauge theory of gravity. They are differential equations of the first order and it is easier to investigate the solutions for different particular configurations of the gauge fields and of space-times.One of the most important property of the self-duality equations is that they imply the Yang-Mills field equations. In this paper we will prove this property for the general case of a gauge theory with compact Lie group of symmetry over a 4-dimensional space-time manifold. It is important to remark that there are 3m independent self-duality equations (of the first order) while the number of Yang-Mills equations is equal to 4m, where m is the dimension of the gauge group. Both of them have 4m unknown functions which are the gauge potentials A μ a (x), a = 1, 2, ....,m; μ = 0, 1, 2, 3. But, we have, in addition, m gauge conditions for A μ a (x), (for example Coulomb, Lorentz or axial gauge) which together with the selfduality equation constitute a system of 4m equations. The Bianchi identities for the self-dual stress tensor F μν a coincide with the Yang-Mills equations and do not imply therefore supplementary conditions. We use the axial gauge in order to obtain the self duality equations for a SU(2) gauge theory over a curved space-time. The compatibility between self-duality and Yang-Mills equations is studied and some classes of solutions are obtained. In fact, we will write the Einstein-Yang-Mills equations and we will analyse only the Yang-Mills sector. The Einstein equations can not be obtained of course from self-duality. They should be obtained if we would consider a gauge theory having P x SU(2) as symmetry group, where P is the Poincare group. More generally, a gauge theory of N-extended supersymmetry can be developed by imposing the self-duality condition. (author)

Possibility of high efficient beam extraction from the CERN SPS with a bent crystal. Simulation results

Energy Technology Data Exchange (ETDEWEB)

Scandale, W. [CERN, European Organization for Nuclear Research, CH-1211 Geneva 23 (Switzerland); Laboratoire de l' AccelerateurLineaire (LAL), Universite Paris SudOrsay, Orsay (France); INFN Sezione di Roma, Piazzale Aldo Moro 2, 00185 Rome (Italy); Kovalenko, A.D.; Taratin, A.M. [Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region (Russian Federation)

2017-03-11

The extraction of the SPS beam of 270 GeV/c protons assisted by a bent crystal was studied by simulation. Two methods for delivering the SPS beam onto a crystal were considered: transverse diffusion and orbit bump of the beam. It was shown that the main condition for high efficient beam extraction with a bent crystal, which is a small divergence of the incident beam, can be fulfilled. Extraction efficiency up to 99% can be reached for both methods of the beam delivering. The irradiation of the electrostatic septum wires during the beam extraction can be considerably reduced.

Shock Tube as an Impulsive Application Device

Directory of Open Access Journals (Sweden)

Soumya Ranjan Nanda

2017-01-01

Full Text Available Current investigations solely focus on application of an impulse facility in diverse area of high-speed aerodynamics and structural mechanics. Shock tube, the fundamental impulse facility, is specially designed and calibrated for present objectives. Force measurement experiments are performed on a hemispherical test model integrated with the stress wave force balance. Similar test model is considered for heat transfer measurements using coaxial thermocouple. Force and heat transfer experiments demonstrated that the strain gauge and thermocouple have lag time of 11.5 and 9 microseconds, respectively. Response time of these sensors in measuring the peak load is also measured successfully using shock tube facility. As an outcome, these sensors are found to be suitable for impulse testing. Lastly, the response of aluminum plates subjected to impulsive loading is analyzed by measuring the in-plane strain produced during deformation. Thus, possibility of forming tests in shock is also confirmed.

Chemical potentials in gauge theories

International Nuclear Information System (INIS)

Actor, A.; Pennsylvania State Univ., Fogelsville

1985-01-01

One-loop calculations of the thermodynamic potential Ω are presented for temperature gauge and non-gauge theories. Prototypical formulae are derived which give Ω as a function of both (i) boson and/or fermion chemical potential, and in the case of gauge theories (ii) the thermal vacuum parameter Asub(O)=const (Asub(μ) is the euclidean gauge potential). From these basic abelian gauge theory formulae, the one-loop contribution to Ω can readily be constructed for Yang-Mills theories, and also for non-gauge theories. (orig.)

On the Effects of Tube Butting on the Structural Performance of Steel Bicycle Frames

Directory of Open Access Journals (Sweden)

Derek Covill

2018-02-01

Full Text Available Previous studies have shown how finite element analysis (FEA can be used to support designers and frame builders in the selection of butted tubes to tune the stiffness and strength behaviour of steel bicycles. The aim of this paper was therefore to analyse the effects of tube butting on the stiffness, stress distribution and energy absorption behaviour of bicycle frames using numerical simulations. Butted tubes were shown to provide a highly effective means to decrease mass whilst producing a disproportionately small change in stress compared with a straight gauge tubeset with a maximum material condition although there was no added benefit in terms of stiffness or strain energy. Conversely, decreasing the wall thickness produced an increase in stress at the tube ends that was disproportionate to the change in mass. This work can now be extended to analyse a fuller set of butted profiles for a range of tube types.

Doses from portable gauges

International Nuclear Information System (INIS)

Linauskas, S.H.

1988-08-01

Field studies to measure actual radiation exposures of operators of commercial moisture-density gauges were undertaken in several regions of Canada. Newly developed bubble detector dosimeter technology and conventional dosimetry such as thermoluminescent dosimeters (TLDs), integrating electronic dosimeters (DRDs), and CR-39 neutron track-etch detectors were used to estimate the doses received by 23 moisture-density gauge operators and maintenance staff. These radiation dose estimates were supported by mapping radiation fields and accounting for the time an operator was near a gauge. Major findings indicate that gauge maintenance and servicing workers were more likely than gauge operators to receive exposures above the level of 5 mSv, and that neutron doses were roughly the same as gamma doses. Gauge operators receive approximately 75% of their dose when transporting and carrying the gauge. Dose to their hands is similar to the dose to their trunks, but the dose to their feet area is 6 to 30 times higher. Gamma radiation is the primary source of radiation contributing to operator dose

Precast, Prestressed Concrete Bent Caps : Volume 1, Preliminary Design Considerations and Experimental Test Program

Science.gov (United States)

2018-04-01

Precast prestressed concrete bent caps may provide significant benefits by enabling accelerated construction of bridge substructures and improve longevity by reducing the propensity for cracking. The Texas Department of Transportation enables the use...

Nonlocal gauge theories

International Nuclear Information System (INIS)

Partovi, M.H.

1982-01-01

From a generalization of the covariant derivative, nonlocal gauge theories are developed. These theories enjoy local gauge invariance and associated Ward identities, a corresponding locally conserved current, and a locally conserved energy-momentum tensor, with the Ward identities implying the masslessness of the gauge field as in local theories. Their ultraviolet behavior allows the presence as well as the absence of the Adler-Bell-Jackiw anomaly, the latter in analogy with lattice theories

SU(2) gauge theory in the maximally Abelian gauge without monopoles

International Nuclear Information System (INIS)

Shmakov, S.Yu.; Zadorozhnyj, A.M.

1995-01-01

We present an algorithm for simulation of SU(2) lattice gauge theory under the maximally Abelian (MA) gauge and first numerical results for the theory without Abelian monopoles. The results support the idea that nonperturbative interaction arises between monopoles and residual Abelian field and the other interactions are perturbative. It is shown that the Gribov region for the theory with the MA gauge fixed is non-connected. 12 refs., 1 tab

Radioactive thickness gauge (1962); Jauge d'epaisseur radioactive (1962)

Energy Technology Data Exchange (ETDEWEB)

Guizerix, J [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1962-07-01

The author describes a thickness gauge in which the scintillating crystal detector alternately 'sees' a radioactive source through the material which is to be measured and then a control source of the same material; the radiations are separated in time by an absorbing valve whose sections are alternately full and hollow. The currents corresponding to the two sources are separated beyond the photomultiplier tube by a detector synchronized with the rotation of the valve. The quotient of these two currents is then obtained with a standard recording potentiometer. It is found that the average value of the response which is in the form G = f(I{sub 1}/I{sub 2}) is not affected by decay of the radioactive sources, and that it is little influenced by variations of high tension, temperature, or properties of the air in the source detector interval. The performance of the gauge is given. (author) [French] L'auteur decrit une jauge d'epaisseur dans laquelle le cristal scintillant detecteur 'voit' alternativement une source radioactive a travers le materiau a mesurer, puis une source de reference de meme nature; la separation des rayonnements est faite dans le temps a l'aide d'un volet absorbeur a secteurs alternativement pleins et creux. Les courants correspondants aux deux sources sont separes apres le tube photomultiplicateur par un detecteur synchrone avec la rotation du volet. On fait ensuite le quotient de ces deux courants a l'aide d'un potientometre enregistreur classique. il resulte de cette disposition que la valeur moyenne de la reponse, qui est de la forme G = f(I{sub 1}/I{sub 2}) n'est pas affectee par la decroissance des sources radioactives, et qu'elle est peu sensible aux variations de haute tension, de temperature ou des proprietes de l'air dans l'intervalle source-detecteur. On donne les performances de cette jauge. (auteur)

Fluid-elastic instability in tube arrays subjected to air-water and steam-water cross-flow

Science.gov (United States)

Mitra, D.; Dhir, V. K.; Catton, I.

2009-10-01

Flow induced vibrations in heat exchanger tubes have led to numerous accidents and economic losses in the past. Efforts have been made to systematically study the cause of these vibrations and develop remedial design criteria for their avoidance. In this research, experiments were systematically carried out with air-water and steam-water cross-flow over horizontal tubes. A normal square tube array of pitch-to-diameter ratio of 1.4 was used in the experiments. The tubes were suspended from piano wires and strain gauges were used to measure the vibrations. Tubes made of aluminum; stainless steel and brass were systematically tested by maintaining approximately the same stiffness in the tube-wire systems. Instability was clearly seen in single phase and two-phase flow and the critical flow velocity was found to be proportional to tube mass. The present study shows that fully flexible arrays become unstable at a lower flow velocity when compared to a single flexible tube surrounded by rigid tubes. It is also found that tubes are more stable in steam-water flow as compared to air-water flow. Nucleate boiling on the tube surface is also found to have a stabilizing effect on fluid-elastic instability.

An improved simulation routine for modelling coherent high-energy proton interactions with bent crystals

CERN Document Server

Forcher, Francesco; Redaelli, Stefano; Zanetti, Marco; CERN. Geneva. ATS Department

2018-01-01

The planes in crystalline solids can constrain the directions that charged particles take as they pass through. Physicists can use this "channelling" property of crystals to steer particle beams. In a bent crystal, for example, channelled particles follow the bend and can change their direction. Several studies are on-going at CERN to verify the possibility of using bent crystals as primary collimators in high energy hadron colliders like the LHC. Simulations have been developed to model the coherent interaction with crystalline planes. The goal of this note is to analyze the data collected on extracted beam from the SPS and develop an improved model to simulate the data’s subtleties, in particular the transition between the volume reflection and amorphous interactions of the beam with crystals.

The light-cone gauge in Polyakov's theory of strings and its relation to the conformal gauge

International Nuclear Information System (INIS)

Tzani, R.

1989-01-01

The author studies the string theory as a gauge theory. The analysis includes the formulation of the interacting bosonic string by fixing the Gervais-Sakita light-cone gauge in Polyakov's path-integral formulation of the theory and the study of the problem of changing gauge in string theory in the context of the functional formulation of the theory. The main results are the following: Mandelstam's picture is obtained from the light-cone gauge fixed Polyakov's theory. Due to the off-diagonal nature of the gauge, the calculation of the determinants differs from the usual (conformal gauge) case. The regularization of the functional integrals associated with these determinants is done by using the conformal-invariance principle. He then shows that the conformal anomaly associated with this new gauge fixing is canceled at dimensions of space-time d = 26. Studying the problem of changing gauge in string theory, he shows the equivalence between the light-cone and conformal gauge in the path-integral formulation of the theory. In particular, by performing a proper change of variables in the commuting and ghost fields in the Polyakov path-integral, the string theory in the conformal gauge is obtained from the light-cone gauge fixed expression. Finally, the problem of changing gauge is generalized to the higher genus surfaces. It is shown that the string theory in the conformal gauge is equivalent to the light-cone gauge fixed theory for surface with arbitrary number of handles

Gauge see-saw: A mechanism for a light gauge boson

Energy Technology Data Exchange (ETDEWEB)

Lee, Hye-Sung, E-mail: hlee@ibs.re.kr; Seo, Min-Seok, E-mail: minseokseo@ibs.re.kr

2017-04-10

There has been rapidly growing interest in the past decade in a new gauge boson which is considerably lighter than the standard model Z boson. A well-known example of this kind is the so-called dark photon, and it is actively searched for in various experiments nowadays. It would be puzzling to have a new gauge boson which is neither massless nor electroweak scale, but possesses a rather small yet nonzero mass. We present a mechanism that can provide a light gauge boson as a result of a mass matrix diagonalization.

Bent-core mesogens with an aromatic unit at the terminal position

Czech Academy of Sciences Publication Activity Database

Bajzikova, K.; Svoboda, J.; Novotná, Vladimíra; Pociecha, D.; Gorecka, E.

2017-01-01

Roč. 41, č. 11 (2017), s. 4672-4679 ISSN 1144-0546 R&D Projects: GA ČR GA16-12150S; GA ČR GA15-02843S Institutional support: RVO:68378271 Keywords : bent- core mesogens * liquid crystals Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.269, year: 2016

Multi-GeV electron and positron channeling in bent silicon crystals

Energy Technology Data Exchange (ETDEWEB)

Sushko, Gennady B., E-mail: sushko@fias.uni-frankfurt.de [Goethe-Universitat Frankfurt am Main, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany); MBN Research Center, Altenhöferallee 3, 60438 Frankfurt am Main (Germany); Korol, Andrei V. [MBN Research Center, Altenhöferallee 3, 60438 Frankfurt am Main (Germany); St. Petersburg State Maritime University, Leninsky Ave. 101, 198262 St. Petersburg (Russian Federation); Solov’yov, Andrey V. [MBN Research Center, Altenhöferallee 3, 60438 Frankfurt am Main (Germany); A.F. Ioffe Physical-Technical Institute, Politekhnicheskaya ul. 26, 194021 St. Petersburg (Russian Federation)

2015-07-15

The planar channeling of 3…20 GeV electrons and positrons in bent Si(1 1 1) crystal was simulated by means of the MBN EXPLORER software package. The results of the simulations are analyzed in terms of dechanneling length characterization, angular distribution of outgoing projectiles and radiation spectrum. The results of calculations are compared with the recent experimental data.

Dynamical supersymmetry breaking and gauge anomalies

International Nuclear Information System (INIS)

Zhang, H.

1991-01-01

Some aspects of supersymmetric gauge theories are discussed. It is shown that dynamical supersymmetry breaking does not occur in supersymmetric QED in higher dimensions. The cancellation of both local (perturbative) and global (non-perturbative) gauge anomalies are also discussed in supersymmetric gauge theories. We argue that there is no dynamical supersymmetry breaking in higher dimensions in any supersymmetric gauge theories free of gauge anomalies. It is also shown that for supersymmetric gauge theories in higher dimensions with a compact connected simple gauge group, when the local anomaly-free condition is satisfied, there can be at most a possible Z 2 global gauge anomaly in extended supersymmetric SO(10) (or spin (10)) gauge theories in D=10 dimensions containing additional Weyl fermions in a spinor representation of SO(10) (or spin (10)). In four dimensions with local anomaly-free condition satisfied, the only possible global gauge anomalies in supersymmetric gauge theories are Z 2 global gauge anomalies for extended supersymmetric SP(2N) (N=rank) gauge theories containing additional Weyl fermions in a representation of SP(2N) with an odd 2nd-order Dynkin index. (orig.)

Gauge-invariant variational methods for Hamiltonian lattice gauge theories

International Nuclear Information System (INIS)

Horn, D.; Weinstein, M.

1982-01-01

This paper develops variational methods for calculating the ground-state and excited-state spectrum of Hamiltonian lattice gauge theories defined in the A 0 = 0 gauge. The scheme introduced in this paper has the advantage of allowing one to convert more familiar tools such as mean-field, Hartree-Fock, and real-space renormalization-group approximation, which are by their very nature gauge-noninvariant methods, into fully gauge-invariant techniques. We show that these methods apply in the same way to both Abelian and non-Abelian theories, and that they are at least powerful enough to describe correctly the physics of periodic quantum electrodynamics (PQED) in (2+1) and (3+1) space-time dimensions. This paper formulates the problem for both Abelian and non-Abelian theories and shows how to reduce the Rayleigh-Ritz problem to that of computing the partition function of a classical spin system. We discuss the evaluation of the effective spin problem which one derives the PQED and then discuss ways of carrying out the evaluation of the partition function for the system equivalent to a non-Abelian theory. The explicit form of the effective partition function for the non-Abelian theory is derived, but because the evaluation of this function is considerably more complicated than the one derived in the Abelian theory no explicit evaluation of this function is presented. However, by comparing the gauge-projected Hartree-Fock wave function for PQED with that of the pure SU(2) gauge theory, we are able to show that extremely interesting differences emerge between these theories even at this simple level. We close with a discussion of fermions and a discussion of how one can extend these ideas to allow the computation of the glueball and hadron spectrum

Design of a PC Based Pressure Indicator Using Inductive Pick-up Type Transducer and Bourdon Tube Sensor

Directory of Open Access Journals (Sweden)

S. C. BERA

2009-08-01

Full Text Available Bourdon tube is a mechanical type pressure sensor and the bourdon gauge measures gauge pressure of a process pipe line or a process tank. But it is a local indicator and special costlier techniques are required to transmit the reading of bourdon gauge to a remote distance. In the present paper, a very simple inductive pick-up type technique has been developed to transmit the reading of bourdon gauge to a remote distance in the form of 1-5 Volt D.C. signal. This signal has been optically isolated to design a PC based pressure indicator using Labtech Note Book Pro software. The theoretical analysis of the whole technique has been presented in the paper. The instrument developed using this technique has been experimentally tested and the experimental results are reported in the paper. A good linearity and repeatability of the instrument has been observed.

Restoration of the local gauge symmetry and color confinement in non-Abelian gauge theories

International Nuclear Information System (INIS)

Hata, Hiroyuki

1982-01-01

Restoration of the local gauge symmetry and its connection to color confinement is investigated in non-Abelian gauge theories with covariant gauge fixing. We consider the Noether current J sub(μ,#betta#)sup(a) of the local gauge transformation with transformation functions #betta#sup(b)(x) linear in x sub(μ); #betta#sup(b)(x) = delta sup(ab)x sub(#betta#). This current is conserved only in the physical subspace of the state vector space and in perturbation theory contains a massless pole communicating to the gauge field. We define the local gauge symmetry restoration as the disappearance of this massless ''Goldstone'' pole from J sub(μ,#betta#)sup(a). The restoration condition is obtained and it coincides exactly with the color confinement criterion proposed earlier by Kugo and Ojima. Quarks and other colored particles are shown to be confined in the local gauge symmetry restored phase by using the Ward identities of J sub(μ,#betta#)sup(a). (author)

Extended gauge sectors at future colliders: Report of the New Gauge Boson Subgroup

International Nuclear Information System (INIS)

Rizzo, T.G.

1996-12-01

The author summarizes the results of the New Gauge Boson Subgroup on the physics of extended gauge sectors at future colliders as presented at the 1996 Snowmass workshop. He discusses the direct and indirect search reaches for new gauge bosons at both hadron and lepton colliders as well as the ability of such machines to extract detailed information on the couplings of these particles to the fermions and gauge bosons of the Standard Model. 41 refs., 18 figs., 5 tabs

The Crystal Backlighter Imager: a spherically-bent crystal imager for radiography on the National Ignition Facility

Science.gov (United States)

Hall, Gareth; Krauland, Christine; Buscho, Justin; Hibbard, Robin; McCarville, Thomas; Lowe-Webb, Roger; Ayers, Shannon; Kalantar, Daniel; Kohut, Thomas; Kemp, G. Elijah; Bradley, David; Bell, Perry; Landen, Otto; Brewster, Nathaniel; Piston, Kenneth

2017-10-01

The Crystal Backlighter Imager (CBI) is a quasi-monochromatic, near-normal incidence, spherically-bent crystal imager being developed for the NIF, which will allow ICF capsule implosions to be radiographed close to stagnation for the first time. This has not been possible using the previous pinhole-based area-backlighter configuration, as the self-emission from the capsule hotspot overwhelms the backlighter in the final stages of the implosion. CBI mitigates the broadband self-emission from the capsule hot spot by using the extremely narrow bandwidth (a few eV) inherent to imagers based on near-normal-incidence Bragg x-ray optics. The development of a diagnostic with the capability to image the capsule during the final stages of the implosion (r less than 200um) is important, as it will allow the shape, integrity and density of the shell to be measured, and will allow the evolution of features, such as the fill tube and capsule support structure, to be imaged close to bang time. The concept and operation of the 11.6keV CBI diagnostic will be discussed, and the first results from experiments on the NIF will be presented. Prepared by LLNL under Contract DE-AC52-07NA27344.

Parastatistics and gauge symmetries

International Nuclear Information System (INIS)

Govorkov, A.B.

1982-01-01

A possible formulation of gauge symmetries in the Green parafield theory is analysed and the SO(3) gauge symmetry is shown to be on a distinct status. The Greenberg paraquark hypothesis turns out to be not equivalent to the hypothesis of quark colour SU(3)sub(c) symmetry. Specific features of the gauge SO(3) symmetry are discussed, and a possible scheme where it is an exact subgroup of the broken SU(3)sub(c) symmetry is proposed. The direct formulation of the gauge principle for the parafield represented by quaternions is also discussed

Implementing general gauge mediation

International Nuclear Information System (INIS)

Carpenter, Linda M.; Dine, Michael; Festuccia, Guido; Mason, John D.

2009-01-01

Recently there has been much progress in building models of gauge mediation, often with predictions different than those of minimal gauge mediation. Meade, Seiberg, and Shih have characterized the most general spectrum which can arise in gauge-mediated models. We discuss some of the challenges of building models of general gauge mediation, especially the problem of messenger parity and issues connected with R symmetry breaking and CP violation. We build a variety of viable, weakly coupled models which exhibit some or all of the possible low energy parameters.

General gauge mediation

International Nuclear Information System (INIS)

Meade, Patrick; Seiberg, Nathan; Shih, David

2009-01-01

We give a general definition of gauge mediated supersymmetry breaking which encompasses all the known gauge mediation models. In particular, it includes both models with messengers as well as direct mediation models. A formalism for computing the soft terms in the generic model is presented. Such a formalism is necessary in strongly-coupled direct mediation models where perturbation theory cannot be used. It allows us to identify features of the entire class of gauge mediation models and to distinguish them from specific signatures of various subclasses. (author)

Photosensitive bent-core liquid crystals based on methyl substituted 3-hydroxybenzoic acid.

Czech Academy of Sciences Publication Activity Database

Kohout, M.; Alaasar, M.; Poryvai, A.; Novotná, Vladimíra; Poppe, S.; Tschierske, C.; Svoboda, J.

2017-01-01

Roč. 7, č. 57 (2017), s. 35805-35813 ISSN 2046-2069 R&D Projects: GA ČR GA16-12150S Institutional support: RVO:68378271 Keywords : liquid crystals * photosensitivity * bent-core liquid crystals * 3-hydroxybenzoic acid Subject RIV: JJ - Other Materials OBOR OECD: Nano-materials (production and properties) Impact factor: 3.108, year: 2016

The holomorphicity of the gauge coupling constant in supersymmetric gauge theories

International Nuclear Information System (INIS)

Li, H.

1993-01-01

Holomorphicity is the analytical dependence of the gauge coupling function, f = 1/g 2 + Θ/8π 2 , on the chiral fields in supergravity and supersymmetric gauge theories. The holomorphic property of 1/g 2 in supersymmetric gauge theories is studied by calculating its dependence on the mass matrix. The general representations of the mass matrix allowed by the constraints of gauge invariance is considered, and calculate the one- and two-loop corrections to 1/g 2 for both super QED and super Yang-Mills theories. For the massive mass matrix it is shown that one- and two-loop corrections to the gauge coupling constant are holomorphic. The reason for two-loop holomorphicity is that the second order logarithmic terms cancel out. For the mass matrix with at least one zero mode, it is recognized that there are two distinct cases which we call pseudo massive and intrinsically massless. For the case of pseudo mass matrix, the reducible representation of the gauge group is (i) complex with equal numbers of irreducible representations and their conjugates, (ii) real, or (iii) pseudo-real. Even though there are massless modes, it is found that the dependence of the gauge coupling constant on the mass matrix is holomorphic. This holomorphicity follows because the mass matrix can be perturbed to regularize the infrared divergence. For the case of intrinsically massless mass matrix, a reducible complex representation with unequal numbers of irreducible representations and their conjugates. The author shows that loop corrections to the gauge coupling constant are non-holomorphic. The reason is an infrared momentum cutoff is used which spins holomorphicity. The results show that, for the pseudo massive case, even though there is an infrared divergence, the one- and two-loop corrections are still holomorphic. Hence, it is concluded that non-holomorphicity is caused by the unbalanced numbers of families and antifamilies in the complex representation

Microstrip silicon detectors in a bent crystal based collimation system: The UA9 experiment

International Nuclear Information System (INIS)

Bolognini, D.

2010-01-01

In a hadron accelerator like Lhc, a collimation system needs to be developed to protect the accelerator itself from the beam loss damage, increasing the beam luminosity. At present, a classical robust multi-stage collimation system (based on amorphous jaws) allows to protect Lhc, but limits the luminosity to the 40% of the nominal value. In order to solve this problem, a series of low-impedance collimation systems is being developed for the second Lhc collimation phase: among these, a key role could be played by bent crystals. In a bent crystal, in fact, charged particles can be deviated in a given direction with a high efficiency, reducing the impedance and increasing the luminosity. After the satisfactory results on extracted beams, it was decided to test bent crystals on a circular accelerator (the Super Proton Synchrotron Sps at CERN): the UA9 experiment was born. In order to qualify the crystal behavior, a tracking system has been developed: the system is based on microstrip silicon detectors readout by self-triggering ASICs with a spatial resolution of the order of 5 μm; the system, completely remotely controlled and based on the optical fiber transmission, would be able to measure the beam halo phase space x - x 1 . This paper, after a brief introduction of the UA9 experiment, will describe the tracking system and the first results obtained in the commissioning phase and data takings with a detector prototype.

Observation of multiple Bragg reflections of neutrons in bent perfect crystals

Czech Academy of Sciences Publication Activity Database

Mikula, Pavol; Vrána, Miroslav; Šaroun, Jan; Seong, B. S.; Moon, MK.

2011-01-01

Roč. 634, č. 1 (2011), S108-S111 ISSN 0168-9002. [International Workshop on Neutron Optics. Grenoble, 17.03.2010-19.03.2010] R&D Projects: GA ČR GAP204/10/0654 Institutional research plan: CEZ:AV0Z10480505 Keywords : Neutron diffraction * Bent perfect crystal * Multiple reflections Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.207, year: 2011

Flexoelectricity in an oxadiazole bent-core nematic liquid crystal

OpenAIRE

Kaur, Sarabjot; Panov, V. P.; Greco, C.; Ferrarini, A.; Görtz, Verena; Goodby, John W.; Gleeson, Helen F.

2014-01-01

We have determined experimentally the magnitude of the difference in the splay and bend flexoelectric coefficients, |e 1 − e 3|, of an oxadiazole bent-core liquid crystal by measuring the critical voltage for the formation of flexodomains together with their wave number. The coefficient |e 1 − e 3| is found to be a factor of 2–3 times higher than in most conventional calamitic nematic liquid crystals, varying from 8 pCm−1 to 20 pCm−1 across the ∼60 K—wide nematic regime. We have also calculat...

Quantum effects for particles channeling in a bent crystal

Energy Technology Data Exchange (ETDEWEB)

Feranchuk, Ilya, E-mail: iferanchuk@gmail.com [Atomic Molecular and Optical Physics Research Group, Ton Duc Thang University, 19 Nguyen Huu Tho Str., Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, 19 Nguyen Huu Tho Str., Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Belarusian State University, 4 Nezavisimosty Ave., 220030 Minsk (Belarus); San, Nguyen Quang [Belarusian State University, 4 Nezavisimosty Ave., 220030 Minsk (Belarus)

2016-09-15

Quantum mechanical theory for channeling of the relativistic charged particles in the bent crystals is considered in the paper. Quantum effects of under-barrier tunneling are essential when the radius of the curvature is closed to its critical value. In this case the wave functions of the quasi-stationary states corresponding to the particles captured in a channel are presented in the analytical form. The efficiency of channeling of the particles and their angular distribution at the exit crystal surface are calculated. Characteristic experimental parameters for observation the quantum effects are estimated.

Deposition of aerosol particles in bent pipe

International Nuclear Information System (INIS)

Matsui, Hiroshi; Ohhata, Tsutomu

1989-01-01

An equation to estimate deposition fraction of aerosol particles in a bent pipe is derived and the validity is verified experimentally. The equation is obtained by assuming that the resultant acceleration of the gravity and the centrifugal force induced in the bend acts on the aerosol particles, and is found to give a relatively accurate estimation of the deposition fraction if a certain correction factor is introduced to the equation. The deposition fraction has a minimum against Reynold number, and the deposition due to centrifugal force dominates at greater Reynolds number than that at the minimum deposition fraction. On the other hand, the smaller the radius of curvature of the bend is, the larger the deposition fraction due to the centrifugal force is. (author)

Some formal problems in gauge theories

International Nuclear Information System (INIS)

Magpantay, J.A.

1980-01-01

The concerns of this thesis are the problems due to the extra degrees of freedom in gauge-invariant theories. Since gauge-invariant Lagrangians are singular, Dirac's consistency formalism and Fadeev's extension are first reviewed. A clarification on the origin of primary constraints is given, and some of the open problems in singular Lagrangian theory are discussed. The criteria in choosing a gauge, i.e., attainability, maintainability and Poincare invariance are summarized and applied to various linear gauges. The effects of incomplete removal of all gauge freedom on the criteria for gauge conditions are described. A simple example in point mechanics that contains some of the features of gauge field theories is given. Finally, we describe a method of constructing gauge-invariant variables in various gauge field theories. For the Abelian theory, the gauge-invariant, transverse potential and Dirac's gauge-invariant fermion field was derived. For the non-Abelian case we introduce a local set of basis vectors and gauge transformations are interpreted as rotations of the basis vectors introduced. The analysis leads to the reformulation of local SU(2) field theory in terms of path-dependent U(1) x U(1) x U(1). However, the analysis fails to include the matter fields as of now

Light-cone gauge versus proper-time gauge for massless spinning particles

International Nuclear Information System (INIS)

Skagerstam, B.S.; Stern, A.

1987-01-01

Although the light-cone gauge is convenient for many applications in physics, it is known to distort topology. We show that as a consequence, some interesting, possibly physical, features of a quantum theory may be missed when working in the light-cone gauge. We shall illustrate this by examining the description of massless spinning particles in an arbitrary number of space-time dimensions. When quantizing such particles in four space-time dimensions (without introducing Grassmann degrees of freedom), the light-cone gauge yields a purely bosonic spectrum, i.e. the helicity λ is integer-valued. The problem is rectified by going to the proper-time gauge; there λ = 0, ±1/2, ±1, ... Upon using the proper-time gauge to quantize massless particle systems in more than four space-time dimensions, we find the following interesting features: Except for space-time dimension d equal to 5 and 9, (i) wave functions cannot be expressed as global functions of momentum (or position). (This is also true for d=4.) Further, for d ≠ 5 and 9, (ii) the helicity group spin (d-2) and (iii) canonical position operators do not exist, globally. (The result that helicity cannot be globally defined resembles a known property of nonabelian monopoles arising in grand unified theories. There, topological obstructions prevent one from defining the color group, globally.) All of the features (i)-(iii) are missed when working in the light-cone gauge. (orig.)

Out-of-plane stability of roller bent steel arches – an experimental investigation

NARCIS (Netherlands)

La Poutre, D.B.; Spoorenberg, R.C.; Snijder, H.H.; Hoenderkamp, J.C.D.

2013-01-01

This paper presents an experimental investigation of the elastic-plastic out-of-plane buckling response of roller bent circular steel arches subjected to a single force applied to the crown. The experiments are used to validate a finite element model described in a related paper. A series of 15

Experimental study on incident wave speed and the mechanisms of deflagration-to-detonation transition in a bent geometry

Science.gov (United States)

Li, L.; Li, J.; Teo, C. J.; Chang, P. H.; Khoo, B. C.

2018-03-01

The study of deflagration-to-detonation transition (DDT) in bent tubes is important with many potential applications including fuel pipeline and mine tunnel designs for explosion prevention and detonation engines for propulsion. The aim of this study is to exploit low-speed incident shock waves for DDT using an S-shaped geometry and investigate its effectiveness as a DDT enhancement device. Experiments were conducted in a valveless detonation chamber using ethylene-air mixture at room temperature and pressure (303 K, 1 bar). High-speed Schlieren photography was employed to keep track of the wave dynamic evolution. Results showed that waves with velocity as low as 500 m/s can experience a successful DDT process through this S-shaped geometry. To better understand the mechanism, clear images of local explosion processes were captured in either the first curved section or the second curved section depending on the inlet wave velocity, thus proving that this S-shaped tube can act as a two-stage device for DDT. Owing to the curved wall structure, the passing wave was observed to undergo a continuous compression phase which could ignite the local unburnt mixture and finally lead to a local explosion and a detonation transition. Additionally, the phenomenon of shock-vortex interaction near the wave diffraction region was also found to play an important role in the whole process. It was recorded that this interaction could not only result in local head-on reflection of the reflected wave on the wall that could ignite the local mixture, and it could also contribute to the recoupling of the shock-flame complex when a detonation wave is successfully formed in the first curved section.

Translational groups as generators of gauge transformations

International Nuclear Information System (INIS)

Scaria, Tomy

2003-01-01

We examine the gauge generating nature of the translational subgroup of Wigner's little group for the case of massless tensor gauge theories and show that the gauge transformations generated by the translational group are only a subset of the complete set of gauge transformations. We also show that, just as in the case of topologically massive gauge theories, translational groups act as generators of gauge transformations in gauge theories obtained by extending massive gauge noninvariant theories by a Stueckelberg mechanism. The representations of the translational groups that generate gauge transformations in such Stueckelberg extended theories can be obtained by the method of dimensional descent. We illustrate these results with the examples of Stueckelberg extended first class versions of Proca, Einstein-Pauli-Fierz, and massive Kalb-Ramond theories in 3+1 dimensions. A detailed analysis of the partial gauge generation in massive and massless second rank symmetric gauge theories is provided. The gauge transformations generated by the translational group in two-form gauge theories are shown to explicitly manifest the reducibility of gauge transformations in these theories

Translational groups as generators of gauge transformations

Science.gov (United States)

Scaria, Tomy

2003-11-01

We examine the gauge generating nature of the translational subgroup of Wigner’s little group for the case of massless tensor gauge theories and show that the gauge transformations generated by the translational group are only a subset of the complete set of gauge transformations. We also show that, just as in the case of topologically massive gauge theories, translational groups act as generators of gauge transformations in gauge theories obtained by extending massive gauge noninvariant theories by a Stückelberg mechanism. The representations of the translational groups that generate gauge transformations in such Stückelberg extended theories can be obtained by the method of dimensional descent. We illustrate these results with the examples of Stückelberg extended first class versions of Proca, Einstein-Pauli-Fierz, and massive Kalb-Ramond theories in 3+1 dimensions. A detailed analysis of the partial gauge generation in massive and massless second rank symmetric gauge theories is provided. The gauge transformations generated by the translational group in two-form gauge theories are shown to explicitly manifest the reducibility of gauge transformations in these theories.

On the dynamics of gauge potential

International Nuclear Information System (INIS)

Tao Jiafu; Li Yuanjie; Zhang Jinru

1992-01-01

The gauge potential is resolved into gauge potential of strength and gauge potential of phase. The phase gauge potential can be described with an equivalent potential of inertial force. A Lagrangian density with phase gauge potential is given and some examples are discussed. The method proposed has been extended to the case of the non-Abelian group

Gauge boson/Higgs boson unification: The Higgs bosons as superpartners of massive gauge bosons

International Nuclear Information System (INIS)

Fayet, P.

1984-01-01

We show how one can use massive gauge superfields to describe, simultaneously, gauge bosons (Wsup(+-), Z, ...) and Higgs bosons (wsup(+-), z, ...) together with their spin-1/2 partners (pairs of winos, zinos, ...), despite their different electroweak properties. This provides a manifestly supersymmetric formulation of spontaneously broken supersymmetric gauge theories, and makes explicit the relations between massive gauge bosons and Higgs bosons. It raises, however, the following question: if the gauge bosons Wsup(+-) and Z and the Higgs bosons wsup(+-) and z are related by supersymmetry, how it is possible that the former couple to leptons and quarks proportionately to g or g', and the latter proportionately to gsub(F)sup(1/2) m (fermions). The paradox is solved as follows: when the Higgs bosons are described by massive gauge superfields, the lagrangian density is non-polynomial and field redefinitions have to be performed, in particular: lepton or quark field -> lepton or quark field + (approx.= Gsub(F)sup(1/2) Higgs field) (lepton or quark field). They automatically regenerate, from the lepton and quark supersymmetric mass terms, the correct Yukawa couplings of Higgs bosons proportional to fermion masses. We also apply this method to the case in which an extra U(1) group is gauged, the standard Higgs boson h 0 being then the superpartner of the new neutral gauge boson U. (orig.)

Comparison of microbiology and visual outcomes of patients undergoing small-gauge and 20-gauge vitrectomy for endophthalmitis

Directory of Open Access Journals (Sweden)

Almeida DRP

2016-01-01

Full Text Available David RP Almeida,1 Eric K Chin,2,3 Shaival S Shah,3 Benjamin Bakall,3 Karen M Gehrs,3 H Culver Boldt,3 Stephen R Russell,3 James C Folk,3 Vinit B Mahajan3,41VitreoRetinal Surgery PA, Minneapolis, MN, 2Retina Consultants of Southern California, Riverside, CA, 3Vitreoretinal Service, Department of Ophthalmology and Visual Sciences, 4Omics Laboratory, University of Iowa, Iowa City, IA, USABackground: The role of pars plana vitrectomy (PPV for endophthalmitis has evolved over recent decades but the literature is lacking on comparisons between small-gauge and 20-gauge vitrectomy.Objective: To evaluate evolving etiological and microbiological trends in patients undergoing vitrectomy for endophthalmitis and to compare culture-positive rates and visual outcomes between small-gauge (23- and 25-gauge and 20-gauge instrumentation during vitrectomy for endophthalmitis.Methods: Ten-year retrospective comparative case series and prospective laboratory in vitro testing. Tertiary care academic referral center. Patients who underwent PPV for endophthalmitis between 2003 and 2013. Vitreous biopsies were obtained in all cases. The effect of vitrectomy gauge (20-, 23-, and 25-gauge and vitreous cutting rate (1,500 and 5,000 cuts per minute on the viability of bacterial culture was evaluated in an in vitro prospective laboratory investigation.Main outcome measures: Comparison of etiology, microbiology culture-positive rates, and visual outcomes between small-gauge and 20-gauge instrumentation in patients undergoing PPV for infectious endophthalmitis.Results: A total of 61 cases of vitrectomy for endophthalmitis were identified over a 10-year period; of these, 34 were treated with small-gauge (23- and 25-gauge vitrectomy and 27 were treated with 20-gauge vitrectomy. In the small-gauge group, 12 cases (35.3% yielded culture-positive results versus 20 cases (74.1% with culture positivity in the 20-gauge cohort (P=0.002. The most common cause of endophthalmitis was

Hidden gauge symmetry

International Nuclear Information System (INIS)

O'Raifeartaigh, L.

1979-01-01

This review describes the principles of hidden gauge symmetry and of its application to the fundamental interactions. The emphasis is on the structure of the theory rather than on the technical details and, in order to emphasise the structure, gauge symmetry and hidden symmetry are first treated as independent phenomena before being combined into a single (hidden gauge symmetric) theory. The main application of the theory is to the weak and electromagnetic interactions of the elementary particles, and although models are used for comparison with experiment and for illustration, emphasis is placed on those features of the application which are model-independent. (author)

Strengthening of a railway bridge with NSMR and CFRP tubes

DEFF Research Database (Denmark)

Täljsten, Björn; Bennitz, Anders; Danielsson, Georg

2008-01-01

Strengthening of structures with CFRP is today considered an accepted method to upgrade concrete structures. In this paper two different CFRP strengthening systems are combined to give extended service life to a Swedish double-trough-double-track railway bridge, constructed in concrete with a 10 ....... Sensors on bars and tubes display proofs of utilization of the CFRP while displacement sensors and strain gauges on the steel reinforcement due to the small loads in the service limit state show minor effect....

Multi-step contrast sensitivity gauge

Science.gov (United States)

Quintana, Enrico C; Thompson, Kyle R; Moore, David G; Heister, Jack D; Poland, Richard W; Ellegood, John P; Hodges, George K; Prindville, James E

2014-10-14

An X-ray contrast sensitivity gauge is described herein. The contrast sensitivity gauge comprises a plurality of steps of varying thicknesses. Each step in the gauge includes a plurality of recesses of differing depths, wherein the depths are a function of the thickness of their respective step. An X-ray image of the gauge is analyzed to determine a contrast-to-noise ratio of a detector employed to generate the image.

Enveloping algebra-valued gauge transformations for non-abelian gauge groups on non-commutative spaces

Science.gov (United States)

Jurco, B.; Schraml, S.; Schupp, P.; Wess, J.

2000-11-01

An enveloping algebra-valued gauge field is constructed, its components are functions of the Lie algebra-valued gauge field and can be constructed with the Seiberg-Witten map. This allows the formulation of a dynamics for a finite number of gauge field components on non-commutative spaces.

Adventures in Coulomb Gauge

International Nuclear Information System (INIS)

Greensite, J.; Olejnik, S.

2003-01-01

We study the phase structure of SU(2) gauge theories at zero and high temperature, with and without scalar matter fields, in terms of the symmetric/broken realization of the remnant gauge symmetry which exists after fixing to Coulomb gauge. The symmetric realization is associated with a linearly rising color Coulomb potential (which we compute numerically), and is a necessary but not sufficient condition for confinement.

An improved simulation routine for modelling coherent high-energy proton interactions with bent crystals

CERN Document Server

AUTHOR|(CDS)2210072; Mirarchi, Daniele; Redaelli, Stefano

The planes in crystalline solids can constrain the directions that charged particles take as they pass through. Physicists can use this "channelling" property of crystals to steer particle beams. In a bent crystal, for example, channelled particles follow the bend and can change their direction. Experiments are being carried out to study in detail this phenomenon. The UA9 collaboration is using high energy protons and heavy ions beams from the SPS accelerator at CERN to verify the possibility of using bent crystals as primary collimators in high energy hadron colliders like the LHC. Simulations have been developed to model the coherent interaction with crystal planes. The goal of the thesis is indeed to analyze the data and develop an improved simulation routine to better describe the data’s subtleties, in particular the transition between the volume reflection and amorphous modes of beam interaction with the crystal.

Released radioactivity reducing device

International Nuclear Information System (INIS)

Miyamoto, Yumi.

1995-01-01

A water scrubber is disposed in a scrubber tank and a stainless steel fiber filter is disposed above the water scrubber. The upper end of the scrubber tank is connected by way of a second bent tube to a capturing vessel incorporating a moisture removing layer and an activated carbon filter. The exit of the capturing vessel is connected to a stack. Upon occurrence of an accident of a BWR-type power plant, gases containing radioactive materials released from a reactor container are discharged into the water scrubber from a first bent tube through a venturi tube nozzle, and water soluble and aerosol-like radioactive materials are captured in the water. Aerosol and splashes of water droplets which can not be captured thoroughly by the water scrubber are captured by the stainless steel fiber filter. Gases passing through the scrubber tank are introduced to a capturing vessel through a second bent tube, and organic iodine is captured by the activated carbon filter. (I.N.)

Notes on gauge theory and gravitation

International Nuclear Information System (INIS)

Wallner, R.P.

1981-01-01

In order to investigate whether Einstein's general relativity theory (GRT) fits into the general scheme of a gauge theory, first the concept of a (classical) gauge theory is outlined in an introductionary spacetime approach. Having thus fixed the notation and the main properties of gauge fields, GRT is examined to find out what the gauge potentials and the corresponding gauge group might be. In this way the possibility of interpreting GRT as a gauge theory of the 4-dimensional translation group T(4) = (R 4 , +), and where the gauge potentials are incorporated in a T(4)-invariant way via orthonormal anholonomic basis 1-forms is considered. To include also the spin aspect a natural extension of GRT is given by gauging also the Lorentz group, whereby a Riemann-Cartan spacetime (U 4 -spacetime) comes into play. (Auth.)

Enveloping algebra-valued gauge transformations for non-abelian gauge groups on non-commutative spaces

International Nuclear Information System (INIS)

Jurco, B.; Schraml, S.; Wess, J.; Schupp, P.

2000-01-01

An enveloping algebra-valued gauge field is constructed, its components are functions of the Lie algebra-valued gauge field and can be constructed with the Seiberg-Witten map. This allows the formulation of a dynamics for a finite number of gauge field components on non-commutative spaces. (orig.)

Enveloping algebra-valued gauge transformations for non-abelian gauge groups on non-commutative spaces

Energy Technology Data Exchange (ETDEWEB)

Jurco, B. [Max-Planck-Institut fuer Mathematik, Bonn (Germany); Schraml, S.; Wess, J. [Max-Planck-Institut fuer Physik, Foehringer Ring 6, 80805 Muenchen (Germany); Sektion Physik, Universitaet Muenchen, Theresienstrasse 37, 80333 Muenchen (Germany); Schupp, P. [Sektion Physik, Universitaet Muenchen, Theresienstrasse 37, 80333 Muenchen (Germany)

2000-11-01

An enveloping algebra-valued gauge field is constructed, its components are functions of the Lie algebra-valued gauge field and can be constructed with the Seiberg-Witten map. This allows the formulation of a dynamics for a finite number of gauge field components on non-commutative spaces. (orig.)

Linear b-gauges for open string fields

International Nuclear Information System (INIS)

Kiermaier, Michael; Zwiebach, Barton; Sen, Ashoke

2008-01-01

Motivated by Schnabl's gauge choice, we explore open string perturbation theory in gauges where a linear combination of antighost oscillators annihilates the string field. We find that in these linear b-gauges different gauge conditions are needed at different ghost numbers. We derive the full propagator and prove the formal properties which guarantee that the Feynman diagrams reproduce the correct on-shell amplitudes. We find that these properties can fail due to the need to regularize the propagator, and identify a large class of linear b-gauges for which they hold rigorously. In these gauges the propagator has a non-anomalous Schwinger representation and builds Riemann surfaces by adding strip-like domains. Projector-based gauges, like Schnabl's, are not in this class of gauges but we construct a family of regular linear b-gauges which interpolate between Siegel gauge and Schnabl gauge

3-Aminophenol based bent-shaped liquid crystals with an amide linking group

Czech Academy of Sciences Publication Activity Database

Kozmik, V.; Horčic, M.; Svoboda, J.; Novotná, Vladimíra; Pociecha, D.

2012-01-01

Roč. 39, č. 8 (2012), s. 943-955 ISSN 0267-8292 R&D Projects: GA ČR(CZ) GAP204/11/0723 Institutional research plan: CEZ:AV0Z10100520 Keywords : liquid crystals * aminophenol * bent-shaped mesogen Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.959, year: 2012 http://dx.doi.org/10.1080/02678292.2012.687781

Evaluation of 25-gauge Quincke and 24 — gauge Gertie Marx ...

African Journals Online (AJOL)

Objective: To compare the insertion characteristics and rate of complications between 25-gauge Quincke and 24-gauge Gertie Marx needles. Design: Prospective, randomized. Setting: University of Benin Teaching Hospital; a university-affiliated tertiary centre. Subjects: Parturients (ASA 1 and 2) scheduled for elective ...

Path integral quantization in the temporal gauge

International Nuclear Information System (INIS)

Scholz, B.; Steiner, F.

1983-06-01

The quantization of non-Abelian gauge theories in the temporal gauge is studied within Feynman's path integral approach. The standard asymptotic boundary conditions are only imposed on the transverse gauge fields. The fictituous longitudinal gauge quanta are eliminated asymptotically by modified boundary conditions. This abolishes the residual time-independent gauge transformations and leads to a unique fixing of the temporal gauge. The resulting path integral for the generating functional respects automatically Gauss's law. The correct gauge field propagator is derived. It does not suffer from gauge singularities at n x k = 0 present in the usual treatment of axial gauges. The standard principal value prescription does not work. As a check, the Wilson loop in temporal gauge is calculated with the new propagator. To second order (and to all orders in the Abelian case) the result agrees with the one obtained in the Feynman and Coulomb gauge. (orig.)

Gauge theories and monopoles

International Nuclear Information System (INIS)

Cabibbo, N.

1983-01-01

This chapter attempts to present some of the fundamental geometrical ideas at the basis of gauge theories. Describes Dirac Monopoles and discusses those ideas that are not usually found in more ''utilitarian'' presentations which concentrate on QCD or on the Glashow-Salam-Weinberg model. This topic was chosen because of the announcement of the possible detection of a Dirac monopole. The existence of monopoles depends on topological features of gauge theories (i.e., on global properties of field configurations which are unique to gauge theories). Discusses global symmetry-local symmetry; the connection; path dependence and the gauge fields; topology and monopoles; the case of SU(3) x U(1); and the 't Hooft-Polyakov monopole

A study of the path-integral quantization of Abelian gauge theories when no explicit gauge-fixing term is included in the bilinear part of the gauge-field action

International Nuclear Information System (INIS)

Phillips, S.

1985-01-01

The mathematical problem of inverting the operator Δ x μν ≡ g μν g αβ δ x α δ x β -δ x μ δ x ν , as it arises in the path-integral quantization of an Abelian gauge theory, such as quantum electrodynamics, when no gauge-fixing Lagrangian field density is included, is studied in this article. Making use of the fact that the Schwinger source functions, which are introduced for the purpose of generating Green's functions, are free of divergence, a result that follows from the conversion of the exponentiated action into a Gaussian form, the apparently noninvertible partial differential equation, Δ x μν L ν (x) J μ (x), can, by the addition and subsequent subtraction of terms containing the divergence of the source function, be cast into a form that does possess a Green's function solution. The gauge-field propagator is the same as that obtained by the conventional technique, which involves gauge fixing when the gauge parameter, α, is set equal to one. Such an analysis suggests also that, provided the effect of fictitious particles that propagate only in closed loops are included for the study of Green's functions in non-Abelian gauge theories in Landau-type gauges, then, in quantizing either Abelian gauge theories or non-Abelian gauge theories in this generic kind of gauge, it is not necessary to add an explicit gauge-fixing term to the bilinear part of the gauge-field action

Gamma-ray streaming in bent ducts and voids

International Nuclear Information System (INIS)

Bourdet, L.; Nimal, J.C.; Vergnaud, T.

1983-05-01

We have developed an analytical method to calculate gamma-ray streaming through straight ducts and a numerical method to study the gamma propagation in bends or in annular clearances. The whole set allows a rigorous treatment of gamma streaming through bent ducts. In the same time a Monte Carlo method allows to study any form of geometry, by using sophisticated biasing techniques. All these developments are made with a simplified albedo. An easy to use code is also proposed to calculate very general albedos and a code to calculate the dose rate due to reflection in a room. Gamma dose rate albedos are determined for all elements and the energy range which concerns fission reactors

Comments on general gauge mediation

International Nuclear Information System (INIS)

Intriligator, Kenneth; Sudano, Matthew

2008-01-01

There has been interest in generalizing models of gauge mediation of supersymmetry breaking. As shown by Meade, Seiberg, and Shih (MSS), the soft masses of general gauge mediation can be expressed in terms of the current two-point functions of the susy-breaking sector. We here give a simple extension of their result which provides, for general gauge mediation, the full effective potential for squark pseudo-D-flat directions. The effective potential reduces to the sfermion soft masses near the origin, and the full potential, away from the origin, can be useful for cosmological applications. We also generalize the soft masses and effective potential to allow for general gauge mediation by Higgsed gauge groups. Finally, we discuss general gauge mediation in the limit of small F-terms, and how the results of MSS connect with the analytic continuation in superspace results, based on a spurion analysis.

Gauge theories

International Nuclear Information System (INIS)

Jarlskog, C.

An introduction to the unified gauge theories of weak and electromagnetic interactions is given. The ingredients of gauge theories and symmetries and conservation laws lead to discussion of local gauge invariance and QED, followed by weak interactions and quantum flavor dynamics. The construction of the standard SU(2)xU(1) model precedes discussion of the unification of weak and electromagnetic interactions and weak neutral current couplings in this model. Presentation of spontaneous symmetry breaking and spontaneous breaking of a local symmetry leads to a spontaneous breaking scheme for the standard SU(2)xU(1) model. Consideration of quarks, leptons, masses and the Cabibbo angles, of the four quark and six quark models and CP violation lead finally to grand unification, followed by discussion of mixing angles in the Georgi-Glashow model, the Higgses of the SU(5) model and proton/ neutron decay in SU(5). (JIW)

Tensile strength of Zr-2.5 Nb pressure tubes: A statistical study

Energy Technology Data Exchange (ETDEWEB)

Shah, Priti Kotak, E-mail: pritik@barc.gov.in [Senior Scientist, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Dubey, J.S.; Datta, D.; Shriwastaw, R.S.; Rath, B.N.; Singh, R.N. [Senior Scientist, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Anantharaman, S. [Head, Post Irradiation Examination Division, Bhabha Atomic Research Centre, Mumbai (India); Chakravartty, J.K. [Director, Materials Group, Bhabha Atomic Research Centre, Mumbai (India)

2015-12-15

Highlights: • Tensile properties in axial and transverse direction for a number of Indian Zr-2.5 Nb PHWR pressure tubes. • Distribution of tensile properties of double-melted and quadruple-melted pressure tubes. • Tensile properties at front-end and back-end of the quadruple melted pressure tubes at room temperature and at 300 °C. - Abstract: In order to get an idea of the statistical variation in the tensile properties of the double-melted as well as quadruple melted Zr-2.5 Nb pressure tubes (PTs) and also the variation in tensile properties between the two ends of the pressure tubes, tension tests were carried out on around 50 pressure tube off-cuts. Longitudinal and transverse tensile specimens were prepared from these off-cuts of pressure tubes of double-melted and quadruple melted types. For quadruple melted pressure tubes the specimens were tested from both front-end and back-end off-cuts. Miniature flat tensile specimens having 1.8 mm width and 1.5 mm thickness and 7.6 mm gauge length were prepared from the pressure tube off-cuts without any flattening treatment. Tension tests were carried out in a screw-driven machine at room temperature and 300 °C for both front-end and back-end off-cuts of each of 16 pressure tubes. In general the transverse specimens showed higher yield strength (YS) and ultimate tensile strength (UTS) compared to the longitudinal specimens. Transverse specimens showed less strain hardening compared to the longitudinal specimens. The axial specimens showed higher uniform (UE) and total elongation (TE) compared to the transverse specimens. Double-melted pressure tubes showed relatively higher strength and lower elongation and larger standard deviation compared to the quadruple melted pressure tubes. Mean values of tensile properties showed that back-end off-cuts were relatively stronger and less ductile compared to the front-end off-cuts.

Renormalization of supersymmetric gauge theories on orbifolds: Brane gauge couplings and higher derivative operators

International Nuclear Information System (INIS)

Groot Nibbelink, Stefan; Hillenbach, Mark

2005-01-01

We consider supersymmetric gauge theories coupled to hypermultiplets on five- and six-dimensional orbifolds and determine the bulk and local fixed point renormalizations of the gauge couplings. We infer from a component analysis that the hypermultiplet does not induce renormalization of the brane gauge couplings on the five-dimensional orbifold S 1 /Z 2 . This is not due to supersymmetry, since the bosonic and fermionic contributions cancel separately. We extend this investigation to T 2 /Z N orbifolds using supergraph techniques in six dimensions. On general Z N orbifolds the gauge couplings do renormalize at the fixed points, except for the Z 2 fixed points of even ordered orbifolds. To cancel the bulk one-loop divergences a dimension six higher derivative operator is needed, in addition to the standard bulk gauge kinetic term.

Vacuum structure of the SU(3) gauge field theory in the Coulomb gauge

International Nuclear Information System (INIS)

Yee, J.H.; Viswanathan, K.S.

1978-01-01

The SU(3) gauge field is studied in the Coulomb gauge. The Gribov ambiguities arising in the Coulomb gauge are analysed. Restricting to a class of spherically symmetric vacua it is shown that there exist non-trivial vacua characterized by a topological number eta=0, +-1/2, and +-2. This must be contrasted with the spherically symmetric SU(2) vacua which are characterized by eta=0, +-1/2. (Auth.)

Gauge-invariant flow equation

Science.gov (United States)

Wetterich, C.

2018-06-01

We propose a closed gauge-invariant functional flow equation for Yang-Mills theories and quantum gravity that only involves one macroscopic gauge field or metric. It is based on a projection on physical and gauge fluctuations. Deriving this equation from a functional integral we employ the freedom in the precise choice of the macroscopic field and the effective average action in order to realize a closed and simple form of the flow equation.

Gauge-invariant Yang-Mills fields and the role of Lorentz gauge condition

International Nuclear Information System (INIS)

Skachkov, N.B.; Shevchenko, O.Yu.

1985-01-01

A new class of gauge-invariant (G.I.) fields is constructed. The inversion formulae that express these fields through the G.I. strength tensor are obtained. It is shown that for the G.I. fields the Lorentz gauge condition appears as the secondary constraint. These fields coincide with the usual ones in some definite gauges. The Dyson-Schwinger equations for the G.I. spinor propagator are derived. It is found that in QED this propagator has a simple pole singularity (p-m) -1 in the infrared limit

Analytical model of the critical current of a bent Nb3Sn strand

International Nuclear Information System (INIS)

Koizumi, Norikiyo; Murakami, Haruyuki; Hemmi, Tsutomu; Nakajima, Hideo

2011-01-01

The critical current performance of a large Nb 3 Sn cable-in-conduit conductor (CICC) was degraded by periodic bending of strands due to a large transverse electromagnetic force. The degradation of each strand due to this bending should be evaluated in calculations of the critical current of a CICC, but a suitable model has not been developed yet. Therefore, the authors have developed a new analytical model which takes into account plastic deformation of copper and bronze and filament breakage. The calculated results were compared with test results for uniformly bent Nb 3 Sn bronze-route strands. The calculated results assuming a high transverse resistance model (HTRM) show good agreement with the test results, a finding which confirms the validity of the model. Because of a much shorter calculation time than for numerical simulation, the developed model seems much more practical for use in calculating the critical current performance of a Nb 3 Sn CICC. In addition, simulation results show that since the neutral axis of a bent strand shifts to the compressive side due to plastic deformation of the copper and bronze, and/or filament breakage, the strand is elongated by bending. This elongation may enhance the strand's critical current performance. Moreover, the calculated results indicate that the dependence of the critical current on the bending strain is affected by the bending history if the strand is excessively bent, especially when filaments are broken. In a real magnet, since a strand in a CICC is normally subject to the maximum electromagnetic force prior to an evaluation of its performance at a lower electromagnetic force, the effect of over-bending should be taken into account in calculations of its critical current performance, especially when filament breakage occurs.

Adding gauge fields to Kaplan's fermions

International Nuclear Information System (INIS)

Blum, T.; Kaerkkaeinen, L.

1994-01-01

We experiment with adding dynamical gauge field to Kaplan (defect) fermions. In the case of U(1) gauge theory we use an inhomogeneous Higgs mechanism to restrict the 3d gauge dynamics to a planar 2d defect. In our simulations the 3d theory produce the correct 2d gauge dynamics. We measure fermion propagators with dynamical gauge fields. They posses the correct chiral structure. The fermions at the boundary of the support of the gauge field (waveguide) are non-chiral, and have a mass two times heavier than the chiral modes. Moreover, these modes cannot be excited by a source at the defect; implying that they are dynamically decoupled. We have also checked that the anomaly relation is fullfilled for the case of a smooth external gauge field. (orig.)

More gaugings of N=8 supergravity

International Nuclear Information System (INIS)

Hull, C.M.

1984-01-01

New non-compact gaugings of N = 8 supergravity are constructed. The gauge groups are SO(p,q) (with p + q = 8) and the group contraction of SO(p,q) about SO(p). The SO(4,4) gauging and the corresponding contraction truncate to gauged N = 4 supergravity theories. (orig.)

Long, elliptically bent, active X-ray mirrors with slope errors <200 nrad.

Science.gov (United States)

Nistea, Ioana T; Alcock, Simon G; Kristiansen, Paw; Young, Adam

2017-05-01

Actively bent X-ray mirrors are important components of many synchrotron and X-ray free-electron laser beamlines. A high-quality optical surface and good bending performance are essential to ensure that the X-ray beam is accurately focused. Two elliptically bent X-ray mirror systems from FMB Oxford were characterized in the optical metrology laboratory at Diamond Light Source. A comparison of Diamond-NOM slope profilometry and finite-element analysis is presented to investigate how the 900 mm-long mirrors sag under gravity, and how this deformation can be adequately compensated using a single, spring-loaded compensator. It is shown that two independent mechanical actuators can accurately bend the trapezoidal substrates to a range of elliptical profiles. State-of-the-art residual slope errors of <200 nrad r.m.s. are achieved over the entire elliptical bending range. High levels of bending repeatability (ΔR/R = 0.085% and 0.156% r.m.s. for the two bending directions) and stability over 24 h (ΔR/R = 0.07% r.m.s.) provide reliable beamline performance.

Introduction to gauge theories

International Nuclear Information System (INIS)

Okun, L.B.

1984-01-01

These lecture notes contain the text of five lectures and a Supplement. The lectures were given at the JINR-CERN School of Physics, Tabor, Czechoslovakia, 5-18 June 1983. The subgect of the lecinvariancetures: gauge of electromagnetic and weak interactions, higgs and supersymmetric particles. The Supplement contains reprints (or excerpts) of some classical papers on gauge invariance by V. Fock, F. London, O. Klein and H. Weyl, in which the concept of gauge invariance was introduced and developed

The renaissance of gauge theory

International Nuclear Information System (INIS)

Moriyasu, K.

1982-01-01

Gauge theory is a classic example of a good idea proposed before its time. A brief historical review of gauge theory is presented to see why it required over 50 years for gauge invariance to be rediscovered as the basic principle governing the fundamental forces of Nature. (author)

Gauge invariance and holographic renormalization

Directory of Open Access Journals (Sweden)

Keun-Young Kim

2015-10-01

Full Text Available We study the gauge invariance of physical observables in holographic theories under the local diffeomorphism. We find that gauge invariance is intimately related to the holographic renormalization: the local counter terms defined in the boundary cancel most of gauge dependences of the on-shell action as well as the divergences. There is a mismatch in the degrees of freedom between the bulk theory and the boundary one. We resolve this problem by noticing that there is a residual gauge symmetry (RGS. By extending the RGS such that it satisfies infalling boundary condition at the horizon, we can understand the problem in the context of general holographic embedding of a global symmetry at the boundary into the local gauge symmetry in the bulk.

Poincare gauge in electrodynamics

International Nuclear Information System (INIS)

Brittin, W.E.; Smythe, W.R.; Wyss, W.

1982-01-01

The gauge presented here, which we call the Poincare gauge, is a generalization of the well-known expressions phi = -rxE 0 and A = 1/2 B 0 x r for the scalar and vector potentials which describe static, uniform electric and magnetic fields. This gauge provides a direct method for calculating a vector potential for any given static or dynamic magnetic field. After we establish the validity and generality of this gauge, we use it to produce a simple and unambiguous method of computing the flux linking an arbitrary knotted and twisted closed circuit. The magnetic flux linking the curve bounding a Moebius band is computed as a simple example. Arguments are then presented that physics students should have the opportunity of learning early in their curriculum modern geometric approaches to physics. (The language of exterior calculus may be as important to future physics as vector calculus was to the past.) Finally, an appendix illustrates how the Poincare gauge (and others) may be derived from Poincare's lemma relating exact and closed exterior differential forms

Gauge invariance and fermion mass dimensions

International Nuclear Information System (INIS)

Elias, V.

1979-05-01

Renormalization-group equation fermion mass dimensions are shown to be gauge dependent in gauge theories possessing non-vector couplings of gauge bosons to fermions. However, the ratios of running fermion masses are explicitly shown to be gauge invariant in the SU(5) and SU(2) x U(1) examples of such theories. (author)

Nuclear radiation moisture gauge calibration standard

International Nuclear Information System (INIS)

1977-01-01

A hydrophobic standard for calibrating nuclear radiation moisture gauges is described. Each standard has physical characteristics and dimensions effective for representing to a nuclear gauge undergoing calibration, an infinite mass of homogeneous hydrogen content. Calibration standards are discussed which are suitable for use with surface gauges and with depth gauges. (C.F.)

Continuum gauge theories

International Nuclear Information System (INIS)

Stora, R.

1976-09-01

The mathematics of gauge fields and some related concepts are discussed: some corrections on the principal fiber bundles emphasize the idea that the present formulation of continuum theories is incomplete. The main ingredients used through the construction of the renormalized perturbation series are then described: the Faddeev Popov argument, and the Faddeev Popov Lagrangian; the Slavnov symmetry and the nature of the Faddeev Popov ghost fields; the Slavnov identity, with an obstruction: the Adler Bardeen anomaly, and its generalization to the local cohomology of the gauge Lie algebra. Some smooth classical configurations of gauge fields which ought to play a prominent role in the evaluation of the functional integral describing the theory are also reviewed

Time-of-flight studies of multiple Bragg reflections in cylindrically bent perfect crystals

Czech Academy of Sciences Publication Activity Database

Mikula, Pavol; Furusaka, M.; Ohkubob, K.; Šaroun, Jan

2012-01-01

Roč. 45, č. 12 (2012), s. 1248-1253 ISSN 0021-8898 R&D Projects: GA AV ČR KJB100480901; GA ČR GAP204/10/0654 Institutional support: RVO:61389005 Keywords : neutron diffraction * time-of-flight method * multiple reflections * bent perfect crystals Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 3.343, year: 2012

Decoupling, effective Lagrangian, and gauge hierarchy in spontaneously broken non-Abelian gauge theories

International Nuclear Information System (INIS)

Kazama, Y.; Yao, Y.

1982-01-01

In spontaneously broken non-Abelian gauge theories which admit gauge hierarchy at the tree level, we show, to all orders in perturbation theory, that (i) the superheavy particles decouple from the light sector at low energies, (ii) an effective low-energy renormalizable theory emerges together with appropriate counterterms, and (iii) the gauge hierarchy can be consistently maintained in the presence of radiative corrections. These assertions are explicitly demonstrated for O(3) gauge theory with two triplets of Higgs particles in a manner easily applicable to more realistic grand unified theories. Furthermore, as a by-product of our analysis, we obtain a systematic method of computing the parameters of the effective low-energy theory via renormalization-group equations to any desired accuracy

First results from bent crystal extraction at the Fermilab Tevatron

International Nuclear Information System (INIS)

1996-07-01

First results from Fermilab Experiment 953 are presented. E853 is an experiment to test the feasibility and efficiency of extracting a low intensity beam from the halo of the Tevatron using channeling in a bent silicon crystal. The motivation for the experiment is to apply crystal extraction to trans-TeV accelerators like the LHC. Extensive simulation work has been carried out. Two accelerator operating modes have been developed for crystal studies, ''kick'' mode and diffusion mode. Results from the first successful extraction in kick mode are presented

An octonionic gauge theory

International Nuclear Information System (INIS)

Lassig, C.C.; Joshi, G.C.

1995-01-01

The nonassociativity of the octonion algebra makes necessitates a bimodule representation, in which each element is represented by a left and a right multiplier. This representation can then be used to generate gauge transformations for the purpose of constructing a field theory symmetric under a gauged octonion algebra, the nonassociativity of which appears as a failure of the representation to close, and hence produces new interactions in the gauge field kinetic term of the symmetric Lagrangian. 5 refs., 1 tab

The topology of gauge fields

International Nuclear Information System (INIS)

Tellis, D.R.

2000-01-01

Full text: Instantons in pure Yang-Mills gauge theory have been studied extensively by physicists and mathematicians alike. The surprisingly rich topological structure plays an important role in hadron structure. A crucial role is played by how the boundary conditions on the gauge fields are imposed. While the topology of gauge fields in pure Yang-Mills gauge theory is understood for the compact manifold of the 4-sphere, the manifold of the 4-torus remains an active area of study. The latter is particularly important in the study of Lattice QCD

Gauge transformations with fractional winding numbers

International Nuclear Information System (INIS)

Abouelsaood, A.

1996-01-01

The role which gauge transformations of noninteger winding numbers might play in non-Abelian gauge theories is studied. The phase factor acquired by the semiclassical physical states in an arbitrary background gauge field when they undergo a gauge transformation of an arbitrary real winding number is calculated in the path integral formalism assuming that a θFF term added to the Lagrangian plays the same role as in the case of integer winding numbers. Requiring that these states provide a representation of the group of open-quote open-quote large close-quote close-quote gauge transformations, a condition on the allowed backgrounds is obtained. It is shown that this representability condition is only satisfied in the monopole sector of a spontaneously broken gauge theory, but not in the vacuum sector of an unbroken or a spontaneously broken non-Abelian gauge theory. It is further shown that the recent proof of the vanishing of the θ parameter when gauge transformations of arbitrary fractional winding numbers are allowed breaks down in precisely those cases where the representability condition is obeyed because certain gauge transformations needed for the proof, and whose existence is assumed, are either spontaneously broken or cannot be globally defined as a result of a topological obstruction. copyright 1996 The American Physical Society

Tensor gauge condition and tensor field decomposition

Science.gov (United States)

Zhu, Ben-Chao; Chen, Xiang-Song

2015-10-01

We discuss various proposals of separating a tensor field into pure-gauge and gauge-invariant components. Such tensor field decomposition is intimately related to the effort of identifying the real gravitational degrees of freedom out of the metric tensor in Einstein’s general relativity. We show that as for a vector field, the tensor field decomposition has exact correspondence to and can be derived from the gauge-fixing approach. The complication for the tensor field, however, is that there are infinitely many complete gauge conditions in contrast to the uniqueness of Coulomb gauge for a vector field. The cause of such complication, as we reveal, is the emergence of a peculiar gauge-invariant pure-gauge construction for any gauge field of spin ≥ 2. We make an extensive exploration of the complete tensor gauge conditions and their corresponding tensor field decompositions, regarding mathematical structures, equations of motion for the fields and nonlinear properties. Apparently, no single choice is superior in all aspects, due to an awkward fact that no gauge-fixing can reduce a tensor field to be purely dynamical (i.e. transverse and traceless), as can the Coulomb gauge in a vector case.

Perturbative ambiguities in Coulomb gauge QCD

International Nuclear Information System (INIS)

Doust, P.

1987-01-01

The naive Coulomb gauge Feynman rules in non-abelian gauge theory give rise to ambiguous integrals, in addition to the usual ultraviolet divergences. Generalizing the work of Cheng and Tsai, these ambiguities are resolved to all orders in perturbation theory, by defining a gauge that interpolates smoothly between the Feynman gauge and the Coulomb gauge. The extra terms V 1 +V 2 of Christ and Lee are identified with certain two-loop ambiguous terms. However, there still seem to be unsolved problems connected with renormalisation. copyright 1987 Academic Press, Inc

New gauged N = 8, D = 4 supergravities

International Nuclear Information System (INIS)

Hull, C M

2003-01-01

New gaugings of four-dimensional N = 8 supergravity are constructed, including one which has a Minkowski space vacuum that preserves N = 2 supersymmetry and in which the gauge group is broken to SU(3) x U(1) 2 . Previous gaugings used the form of the ungauged action which is invariant under a rigid SL (8,R) symmetry and promoted a 28-dimensional subgroup (SO(8), SO(p, 8 - p) or the non-semi-simple contraction CSO(p, q, 8 - p - q)) to a local gauge group. Here, a dual form of the ungauged action is used which is invariant under SU*(8) instead of SL (8,R) and new theories are obtained by gauging 28-dimensional subgroups of SU*(8). The gauge groups are non-semi-simple and are different real forms of the CSO(2p, 8 - 2p) groups, denoted as CSO*(2p, 8 - 2p), and the new theories have a rigid SU(2) symmetry. The five-dimensional gauged N = 8 supergravities are dimensionally reduced to D = 4. The D = 5, SO(p, 6 - p) gauge theories reduce, after a duality transformation, to the D = 4, CSO(p, 6 - p, 2) gauging while the SO*(6) gauge theory reduces to the D = 4, CSO*(6, 2) gauge theory. The new theories are related to the old ones via an analytic continuation. The non-semi-simple gaugings can be dualized to forms with different gauge groups

Gamma-ray streaming in straight pipes and bent ducts

International Nuclear Information System (INIS)

Eid, M.; Diop, C.M.; Nimal, J.C.

1985-04-01

An important shielding problem is the gamma-ray streaming through voids. These problems are encountered in the reactors and reprocessing plants. A Monte Carlo method has been choosed as one of the most powerful technics to solve this kind of problems. Here in that frame, a biasing system which is adapted for two types of geometries is proposed: straight pipes and bent ducts. A code has been written applying this technique. The numerical results obained show the efficiency and the very good economy of the method proposed. It is hoped to extend the method to deal with more complex geometries and polykinetic situation as well

What's wrong with anomalous chiral gauge theory?

International Nuclear Information System (INIS)

Kieu, T.D.

1994-05-01

It is argued on general ground and demonstrated in the particular example of the Chiral Schwinger Model that there is nothing wrong with apparently anomalous chiral gauge theory. If quantised correctly, there should be no gauge anomaly and chiral gauge theory should be renormalisable and unitary, even in higher dimensions and with non-Abelian gauge groups. Furthermore, it is claimed that mass terms for gauge bosons and chiral fermions can be generated without spoiling the gauge invariance. 19 refs

THE SPINDLE: AN IRRADIATED DISK AND BENT PROTOSTELLAR JET IN ORION

Energy Technology Data Exchange (ETDEWEB)

Bally, John; Youngblood, Allison; Ginsburg, Adam, E-mail: John.Bally@colorado.edu, E-mail: Allison.Youngblood@colorado.edu, E-mail: Adam.Ginsburg@colorado.edu [Department of Astrophysical and Planetary Sciences, University of Colorado, UCB 389, Boulder, CO 80309 (United States)

2012-09-10

We present Hubble Space Telescope observations of a bent, pulsed Herbig-Haro jet, HH 1064, emerging from the young star Parenago 2042 embedded in the H II region NGC 1977 located about 30' north of the Orion Nebula. This outflow contains eight bow shocks in the redshifted western lobe and five bow shocks in the blueshifted eastern lobe. Shocks within a few thousand AU of the source star exhibit proper motions of {approx}160 km s{sup -1} but motions decrease with increasing distance. Parenago 2042 is embedded in a proplyd-a photoevaporating protoplanetary disk. A remarkable set of H{alpha} arcs resembling a spindle surround the redshifted (western) jet. The largest arc with a radius of 500 AU may trace the ionized edge of a circumstellar disk inclined by {approx}30 Degree-Sign . The spindle may be the photoionized edge of either a {approx}3 km s{sup -1} FUV-driven wind from the outer disk or a faster MHD-powered flow from an inner disk. The HH 1064 jet appears to be deflected north by photoablation of the south-facing side of a mostly neutral jet beam. V2412 Ori, located 1' west of Parenago 2042 drives a second bent flow, HH 1065. Both HH 1064 and 1065 are surrounded by LL Ori-type bows marking the boundary between the outflow cavity and the surrounding nebula.

Rain Gauges Handbook

Energy Technology Data Exchange (ETDEWEB)

Bartholomew, M. J. [Brookhaven National Lab. (BNL), Upton, NY (United States)

2016-01-01

To improve the quantitative description of precipitation processes in climate models, the Atmospheric Radiation Measurement (ARM) Climate Research Facility deployed rain gauges located near disdrometers (DISD and VDIS data streams). This handbook deals specifically with the rain gauges that make the observations for the RAIN data stream. Other precipitation observations are made by the surface meteorology instrument suite (i.e., MET data stream).

A strain gauge

DEFF Research Database (Denmark)

2017-01-01

The invention relates to a strain gauge of a carrier layer and a meandering measurement grid (101) positioned on the carrier layer, wherein the measurement grid comprises a number of measurement grid sections placed side by side with gaps in between, and a number of end loops (106) interconnecting...... relates to a method for manufacturing a strain gauge as mentioned above....

Do existing research reactors teach us all about beam tube optimization?

International Nuclear Information System (INIS)

Roegler, Hans Joachim; Feltes, Wolfgang

1998-01-01

The contribution makes the attempt to analyse the data base available in the literature and in Siemens' own projects and to find out potential systematics from the existing research reactor with beam tubes, separated into reactors with different reflectors and distinguished for tangential and radial tubes and cold neutron sources, resp. Some generic calculations serve as gauging data. The contribution is not meant as critics on any design.The results might serve supporting designers and operators when evaluating the pros and cons of existing or planned design in terms of the optimum beam tubes. Existing lacks of systematics are evaluated in view of suitable explanations and constraints, which do not allow optimisation. Examples pf such constraints are the different material layers between fuel zone and reflector zone which have various reasons. The limited data in the literature plus the numerous lacks of precision of the representation of those data should be an incentive to improve the performed analysis by collecting more exact data and re-doing the evaluation before answering the title-question really. (author)

Do existing research reactors teach us all about beam tube optimisation?

International Nuclear Information System (INIS)

Roegler, Hans-Joachim; Feltes, Wolfgang

1998-01-01

The contribution makes the attempt to analyse the data base available in the literature and in Siemens' own projects and to find out potential systematics from the existing research reactors with beam tubes, separated into reactors with different reflectors and distinguished for tangential and radial tubes and cold neutron sources, respectively some generic calculations serve as gauging data. The contribution is not meant as critics on any design. The results might serve supporting designers and operators when evaluating the pros and cons of existing or planned design in terms of the optimum beam tubes. Existing lacks of systematics are evaluated in view of suitable explanations and constraints, which do not allow optimisation. Examples of such constraints are the different material layers between fuel zone and reflector zone which have various reasons. The limited data in the literature plus the numerous lacks of precision of the representation of those data should be an incentive to improve the performed analysis by collecting more exact data and re-doing the evaluation before answering the title question really

Electromagnetic dipole moments of charged baryons with bent crystals at the LHC

Energy Technology Data Exchange (ETDEWEB)

Bagli, E.; Bandiera, L.; Guidi, V.; Mazzolari, A. [Universita di Ferrara, Ferrara (Italy); INFN, Sezione di Ferrara (Italy); Cavoto, G. [' ' Sapienza' ' Universita di Roma, Rome (Italy); INFN, Sezione di Roma (Italy); Henry, L.; Martinez Vidal, F.; Ruiz Vidal, J. [IFIC, Universitat de Valencia-CSIC, Valencia (Spain); Marangotto, D. [Universita di Milano, Milan (Italy); INFN, Sezione di Milano (Italy); Merli, A.; Neri, N. [Universita di Milano, Milan (Italy); CERN, Geneva (Switzerland); INFN, Sezione di Milano (Italy)

2017-12-15

We propose a unique program of measurements of electric and magnetic dipole moments of charm, beauty and strange charged baryons at the LHC, based on the phenomenon of spin precession of channeled particles in bent crystals. Studies of crystal channeling and spin precession of positively- and negatively-charged particles are presented, along with feasibility studies and expected sensitivities for the proposed experiment using a layout based on the LHCb detector. (orig.)

Gauge fields

International Nuclear Information System (INIS)

Itzykson, C.

1978-01-01

In these notes the author provides some background on the theory of gauge fields, a subject of increasing popularity among particle physicists (and others). Detailed motivations and applications which are covered in the other lectures of this school are not presented. In particular the application to weak interactions is omitted by referring to the introduction given by J. Ilipoulos a year ago (CERN Report 76-11). The aim is rather to stress those aspects which suggest that gauge fields may play some role in a future theory of strong interactions. (Auth.)

Pollen tube growth test (PTGT) in environmental biomonitoring and predictive radiation biology studies: problem and prospect

International Nuclear Information System (INIS)

Pandey, Devi D.

2012-01-01

In Environmental and Human Bio monitoring studies of Hazardous xenobiotics over living system particularly at cell level, it is desirable to have easy and sensitive test system like Cell Viability assay, MNT, Cell Culture photo toxicity Test, PTGT etc. Out of these the PTGT quite better than other because the in vitro culture of pollen grain can provides a sensitive indication of toxicity at cellular level, since germination and growth of pollen tube will inhibited in presence of toxic substance like DDT, Heavy metal, even Radionuclide's. This test system is easy, economical and widely accepted through out world. In PTGT pollen tube never containing Chloroplast or other plastids so pollen tube resembles animals more than a plant organ and is therefore also a suitable as model for Genotoxicity Assessment of compounds harmful to animal and humans. Lack of plastids in PT, PTGT will not identify the toxic effect of compounds that targets Non cyclic and cyclic photoposphorylation of photosynthesis. This test system valid in International Toxicity Testing Protocol. But this method is time consuming and problem in measurement of pollen tube growing in a culture medium became usually bent and make measurement difficult. Other disadvantage of this method is requirement of DMSO to dissolve test substance of low water suitability in culture medium. DMSO shown to have no effect on PTG at Concentration not more than 1% but some extent interfere with results. Values of PTG are quantified in ED50/IC50 that is the concentration of test compounds that reduces pollen tube growth to 50% of control. So PTGT could be very sensitive and easy to assess in common lab in International way. (author)

Development of a bent Laue beam-expanding double-crystal monochromator for biomedical X-ray imaging

International Nuclear Information System (INIS)

Martinson, Mercedes; Samadi, Nazanin; Belev, George; Bassey, Bassey; Lewis, Rob; Aulakh, Gurpreet; Chapman, Dean

2014-01-01

A bent Laue beam-expanding double-crystal monochromator was developed and tested at the Biomedical Imaging and Therapy beamline at the Canadian Light Source. The expander will reduce scanning time for micro-computed tomography and allow dynamic imaging that has not previously been possible at this beamline. The Biomedical Imaging and Therapy (BMIT) beamline at the Canadian Light Source has produced some excellent biological imaging data. However, the disadvantage of a small vertical beam limits its usability in some applications. Micro-computed tomography (micro-CT) imaging requires multiple scans to produce a full projection, and certain dynamic imaging experiments are not possible. A larger vertical beam is desirable. It was cost-prohibitive to build a longer beamline that would have produced a large vertical beam. Instead, it was proposed to develop a beam expander that would create a beam appearing to originate at a source much farther away. This was accomplished using a bent Laue double-crystal monochromator in a non-dispersive divergent geometry. The design and implementation of this beam expander is presented along with results from the micro-CT and dynamic imaging tests conducted with this beam. Flux (photons per unit area per unit time) has been measured and found to be comparable with the existing flat Bragg double-crystal monochromator in use at BMIT. This increase in overall photon count is due to the enhanced bandwidth of the bent Laue configuration. Whilst the expanded beam quality is suitable for dynamic imaging and micro-CT, further work is required to improve its phase and coherence properties

Gauged U(1) clockwork theory

Science.gov (United States)

Lee, Hyun Min

2018-03-01

We consider the gauged U (1) clockwork theory with a product of multiple gauge groups and discuss the continuum limit of the theory to a massless gauged U (1) with linear dilaton background in five dimensions. The localization of the lightest state of gauge fields on a site in the theory space naturally leads to exponentially small effective couplings of external matter fields localized away from the site. We discuss the implications of our general discussion with some examples, such as mediators of dark matter interactions, flavor-changing B-meson decays as well as D-term SUSY breaking.

Influence of the gauge length on the accuracy of long-gauge sensors employed in monitoring of prismatic beams

International Nuclear Information System (INIS)

Glisic, Branko

2011-01-01

Depending on the geometric basis of measurement (gauge length), discrete strain sensors used in structural monitoring of civil engineering structures can be considered as short-gauge sensors or long-gauge sensors. Long-gauge sensors measure average strain over the gauge lengths and are used for global monitoring of structures, in particular, those built of inhomogeneous materials. However, the strain distribution along the sensor's gauge length may be nonlinear and the measured average strain value that is commonly attributed to the midpoint of the sensor may be different from the real value of strain at that point. Consequently, excessively long sensors may feature significant errors in measurement. However, short-gauge sensors are more susceptible to other types of measurement error, most notably, error caused by discontinuities (open cracks) distributed in the monitored material. Thus an optimum gauge length is to be found. The error in average strain measurement inherent to the sensor's gauge length introduced by the strain distribution and discontinuities in the monitored material is modelled for the most common applications met in civil engineering practice. The modelling takes into account the geometric properties of the monitored structure and various load cases. Guidelines for the selection of an appropriate gauge length are proposed, and tables for measurement error estimation are presented

Noncommutative gauge theory for Poisson manifolds

Energy Technology Data Exchange (ETDEWEB)

Jurco, Branislav E-mail: jurco@mpim-bonn.mpg.de; Schupp, Peter E-mail: schupp@theorie.physik.uni-muenchen.de; Wess, Julius E-mail: wess@theorie.physik.uni-muenchen.de

2000-09-25

A noncommutative gauge theory is associated to every Abelian gauge theory on a Poisson manifold. The semi-classical and full quantum version of the map from the ordinary gauge theory to the noncommutative gauge theory (Seiberg-Witten map) is given explicitly to all orders for any Poisson manifold in the Abelian case. In the quantum case the construction is based on Kontsevich's formality theorem.

Noncommutative gauge theory for Poisson manifolds

International Nuclear Information System (INIS)

Jurco, Branislav; Schupp, Peter; Wess, Julius

2000-01-01

A noncommutative gauge theory is associated to every Abelian gauge theory on a Poisson manifold. The semi-classical and full quantum version of the map from the ordinary gauge theory to the noncommutative gauge theory (Seiberg-Witten map) is given explicitly to all orders for any Poisson manifold in the Abelian case. In the quantum case the construction is based on Kontsevich's formality theorem

Gastrostomy Tube (G-Tube)

Science.gov (United States)

... any of these problems: a dislodged tube a blocked or clogged tube any signs of infection (including redness, swelling, or warmth at the tube site; discharge that's yellow, green, or foul-smelling; fever) excessive bleeding or drainage from the tube site severe abdominal pain lasting ...

Gauge Theories in the Twentieth Century

CERN Document Server

2001-01-01

By the end of the 1970s, it was clear that all the known forces of nature (including, in a sense, gravity) were examples of gauge theories , characterized by invariance under symmetry transformations chosen independently at each position and each time. These ideas culminated with the finding of the W and Z gauge bosons (and perhaps also the Higgs boson). This important book brings together the key papers in the history of gauge theories, including the discoveries of: the role of gauge transformations in the quantum theory of electrically charged particles in the 1920s; nonabelian gauge groups

Construction of U-gauge Green's functions of gauge theories with spontaneous symmetry breaking and Slavnov identities

International Nuclear Information System (INIS)

Flume, R.

1978-01-01

The unitary (U) gauge Green's functions of the U(1) and SU(2) Higgs-Kibble models are constructed applying a renormalized point transformation and a non-local gauge changing transformation to a manifestly renormalizable (R gauge) version of the respective theory. It is shown that the cancellation mechanism known as 'tree graph unitarity' rendering in tree graph approximation a smooth high energy behaviour of the U gauge Green's functions on mass shell can in a natural way be extended to all orders of perturbation theory. The conditions imposed by this 'generalized tree graph unitarity' on the renormalization programme are shown to be equivalent with the requirement of renormalized Slavnov identities for the R gauge Green's functions

Evaluation of a timber column bent substructure after more than 60 years in-service

Science.gov (United States)

James P. Wacker; Xiping Wang; Douglas R. Rammer; William J. Nelson

2011-01-01

This paper describes both the field evaluation and laboratory testing of two timber-column-bent bridge substructures. These substructures served as intermediate pier supports for the East Deer Park Drive Bridge located in Gaithersburg, Maryland. A field evaluation of the bridge substructure was conducted in September 2008. Nondestructive testing was performed with a...

Gauge field theories

International Nuclear Information System (INIS)

Leite Lopes, J.

1981-01-01

The book is intended to explain, in an elementary way, the basic notions and principles of gauge theories. Attention is centred on the Salem-Weinberg model of electro-weak interactions, as well as neutrino-lepton scattering and the parton model. Classical field theory, electromagnetic, Yang-Mills and gravitational gauge fields, weak interactions, Higgs mechanism and the SU(5) model of grand unification are also discussed. (U.K.)

Light-induced gauge fields for ultracold atoms

Science.gov (United States)

Goldman, N.; Juzeliūnas, G.; Öhberg, P.; Spielman, I. B.

2014-12-01

Gauge fields are central in our modern understanding of physics at all scales. At the highest energy scales known, the microscopic universe is governed by particles interacting with each other through the exchange of gauge bosons. At the largest length scales, our Universe is ruled by gravity, whose gauge structure suggests the existence of a particle—the graviton—that mediates the gravitational force. At the mesoscopic scale, solid-state systems are subjected to gauge fields of different nature: materials can be immersed in external electromagnetic fields, but they can also feature emerging gauge fields in their low-energy description. In this review, we focus on another kind of gauge field: those engineered in systems of ultracold neutral atoms. In these setups, atoms are suitably coupled to laser fields that generate effective gauge potentials in their description. Neutral atoms ‘feeling’ laser-induced gauge potentials can potentially mimic the behavior of an electron gas subjected to a magnetic field, but also, the interaction of elementary particles with non-Abelian gauge fields. Here, we review different realized and proposed techniques for creating gauge potentials—both Abelian and non-Abelian—in atomic systems and discuss their implication in the context of quantum simulation. While most of these setups concern the realization of background and classical gauge potentials, we conclude with more exotic proposals where these synthetic fields might be made dynamical, in view of simulating interacting gauge theories with cold atoms.

Light-induced gauge fields for ultracold atoms

International Nuclear Information System (INIS)

Goldman, N; Juzeliūnas, G; Öhberg, P; Spielman, I B

2014-01-01

Gauge fields are central in our modern understanding of physics at all scales. At the highest energy scales known, the microscopic universe is governed by particles interacting with each other through the exchange of gauge bosons. At the largest length scales, our Universe is ruled by gravity, whose gauge structure suggests the existence of a particle—the graviton—that mediates the gravitational force. At the mesoscopic scale, solid-state systems are subjected to gauge fields of different nature: materials can be immersed in external electromagnetic fields, but they can also feature emerging gauge fields in their low-energy description. In this review, we focus on another kind of gauge field: those engineered in systems of ultracold neutral atoms. In these setups, atoms are suitably coupled to laser fields that generate effective gauge potentials in their description. Neutral atoms ‘feeling’ laser-induced gauge potentials can potentially mimic the behavior of an electron gas subjected to a magnetic field, but also, the interaction of elementary particles with non-Abelian gauge fields. Here, we review different realized and proposed techniques for creating gauge potentials—both Abelian and non-Abelian—in atomic systems and discuss their implication in the context of quantum simulation. While most of these setups concern the realization of background and classical gauge potentials, we conclude with more exotic proposals where these synthetic fields might be made dynamical, in view of simulating interacting gauge theories with cold atoms. (review article)

Gauss decomposition, Wakimoto realisation and gauged WZNW models

International Nuclear Information System (INIS)

Arfaei, H.; Mohammedi, N.

1993-10-01

The implications of gauging the Wess-Zumino-Novikov-Witten (WZNW) model using the Gauss decomposition of the group elements are explored. We show that, contrary to standard gauging of WZNW models, this gauging is carried out by minimally coupling the gauge fields. We find that this gauging, in the case of gauging an abelian vector subgroup, differs from the standard one by terms proportional to the field strength of the gauge fields. We prove that gauging an abelian vector subgroup does not have a nonlinear sigma model interpretation. This is because the target-space metric resulting from the integration over the gauge fields is degenerate. We demonstrate, however, that this kind of gauging has a natural interpretation in terms of Wakimoto variables. (orig.)

Parameter space of general gauge mediation

International Nuclear Information System (INIS)

Rajaraman, Arvind; Shirman, Yuri; Smidt, Joseph; Yu, Felix

2009-01-01

We study a subspace of General Gauge Mediation (GGM) models which generalize models of gauge mediation. We find superpartner spectra that are markedly different from those of typical gauge and gaugino mediation scenarios. While typical gauge mediation predictions of either a neutralino or stau next-to-lightest supersymmetric particle (NLSP) are easily reproducible with the GGM parameters, chargino and sneutrino NLSPs are generic for many reasonable choices of GGM parameters.

Relaxation of axially confined 400 GeV/c protons to planar channeling in a bent crystal

International Nuclear Information System (INIS)

Bandiera, L.; Mazzolari, A.; Bagli, E.; Germogli, G.; Guidi, V.; Sytov, A.; Kirillin, I.V.; Shul'ga, N.F.; Berra, A.; Lietti, D.; Prest, M.; De Salvador, D.; Vallazza, E.

2016-01-01

An investigation on the mechanism of relaxation of axially confined 400 GeV/c protons to planar channeling in a bent crystal was carried out at the extracted line H8 from CERN Super Proton Synchrotron. The experimental results were critically compared to computer simulations, showing a good agreement. We identified a necessary condition for the exploitation of axial confinement or its relaxation for particle beam manipulation in high-energy accelerators. We introduce the idea of using a short bent crystal, aligned with one of its main axis to the beam direction, as a beam steerer or a beam splitter with adjustable intensity in the field of particle accelerators. In particular, in the latter case, a complete relaxation from axial confinement to planar channeling takes place, resulting in beam splitting into the two strongest skew planar channels. (orig.)

Relaxation of axially confined 400 GeV/c protons to planar channeling in a bent crystal

Energy Technology Data Exchange (ETDEWEB)

Bandiera, L.; Mazzolari, A.; Bagli, E.; Germogli, G.; Guidi, V. [Universita di Ferrara, Dipartimento di Fisica, Ferrara (Italy); INFN, Ferrara (Italy); Sytov, A. [Universita di Ferrara, Dipartimento di Fisica, Ferrara (Italy); Belarusian State University, Research Institute for Nuclear Problems, Minsk (Belarus); INFN, Ferrara (Italy); Kirillin, I.V. [National Science Center ' ' Kharkov Institute of Physics and Technology' ' , Akhiezer Institute for Theoretical Physics, Kharkov (Ukraine); Shul' ga, N.F. [National Science Center ' ' Kharkov Institute of Physics and Technology' ' , Akhiezer Institute for Theoretical Physics, Kharkov (Ukraine); V.N. Karazin Kharkov National University, Kharkov (Ukraine); Berra, A.; Lietti, D.; Prest, M. [Universita dell' Insubria, Como (Italy); INFN Sezione di Milano Bicocca, Milan (Italy); De Salvador, D. [INFN Laboratori Nazionali di Legnaro, Legnaro (Italy); Universita di Padova, Dipartimento di Fisica, Padua (Italy); Vallazza, E. [INFN Sezione di Trieste, Trieste (Italy)

2016-02-15

An investigation on the mechanism of relaxation of axially confined 400 GeV/c protons to planar channeling in a bent crystal was carried out at the extracted line H8 from CERN Super Proton Synchrotron. The experimental results were critically compared to computer simulations, showing a good agreement. We identified a necessary condition for the exploitation of axial confinement or its relaxation for particle beam manipulation in high-energy accelerators. We introduce the idea of using a short bent crystal, aligned with one of its main axis to the beam direction, as a beam steerer or a beam splitter with adjustable intensity in the field of particle accelerators. In particular, in the latter case, a complete relaxation from axial confinement to planar channeling takes place, resulting in beam splitting into the two strongest skew planar channels. (orig.)

Two-dimensional fluid dynamics in a sharply bent channel: Laminar flow, separation bubble, and vortex dynamics

Science.gov (United States)

Matsumoto, Daichi; Fukudome, Koji; Wada, Hirofumi

2016-10-01

Understanding the hydrodynamic properties of fluid flow in a curving pipe and channel is important for controlling the flow behavior in technologies and biomechanics. The nature of the resulting flow in a bent pipe is extremely complicated because of the presence of a cross-stream secondary flow. In an attempt to disentangle this complexity, we investigate the fluid dynamics in a bent channel via the direct numerical simulation of the Navier-Stokes equation in two spatial dimensions. We exploit the absence of secondary flow from our model and systematically investigate the flow structure along the channel as a function of both the bend angle and Reynolds number of the laminar-to-turbulent regime. We numerically suggest a scaling relation between the shape of the separation bubble and the flow conductance, and construct an integrated phase diagram.

Vacuum-assisted breast biopsy: A comparison of 11-gauge and 8-gauge needles in benign breast disease

Directory of Open Access Journals (Sweden)

Kraemer Bernhard

2008-05-01

Full Text Available Abstract Background Minimal invasive breast biopsy is standard care for the diagnosis of suspicious breast lesions. There are different vacuum biopsy (VB systems in use. The aim of the study was to determine the differences between the 8-gauge and the 11-gauge needle with respect to a diagnostic reliability, b complication rate and c subjective perception of pain when used for vacuum-assisted breast biopsy. Methods Between 01/2000 and 09/2004, 923 patients at St. Josefs-Hospital Wiesbaden underwent VB using the Mammotome® (Ethicon Endosurgery, Hamburg. Depending on preoperative detection, the procedure was performed under sonographic or mammographic guidance under local anaesthesia. All patients included in the study were followed up both clinically and using imaging techniques one week after the VB and a second time after a median of 41 months. Excisional biopsy on the ipsilateral breast was an exclusion criteria. Subjective pain scores were recorded on a scale of 0 – 10 (0 = no pain, 10 = unbearable pain. The mean age of the patients was 53 years (30 – 88. Results 123 patients were included in the study in total. 48 patients were biopsied with the 8-gauge needle and 75 with the 11-gauge needle. The use of the 8-gauge needle did not show any significant differences to the 11-gauge needle with regard to diagnostic reliability, complication rate and subjective perception of pain. Conclusion Our data show that there are no relevant differences between the 8-gauge and 11-gauge needle when used for VB. Under sonographic guidance, the use of the 8-gauge needle is recommended for firm breast tissue due to its sharp scalpel point and especially for complete removal of benign lesions. We did not find any advantages in the use of the larger 8-gauge needle compared to the 11-gauge needle in the mammography setting. The utilisation costs of the 8-gauge needle are somewhat higher.

Comparison of photon organ and effective dose coefficients for PIMAL stylized phantom in bent positions in standard irradiation geometries

Energy Technology Data Exchange (ETDEWEB)

Dewji, Shaheen; Hiller, Mauritius [Oak Ridge National Laboratory, Center for Radiation Protection Knowledge, Environmental Sciences Division, Oak Ridge, TN (United States); Reed, K.L. [Georgia Institute of Technology, Nuclear and Radiological Engineering Program, Atlanta, GA (United States)

2017-08-15

Computational phantoms with articulated arms and legs have been constructed to enable the estimation of radiation dose in different postures. Through a graphical user interface, the Phantom wIth Moving Arms and Legs (PIMAL) version 4.1.0 software can be employed to articulate the posture of a phantom and generate a corresponding input deck for the Monte Carlo N-Particle (MCNP) radiation transport code. In this work, photon fluence-to-dose coefficients were computed using PIMAL to compare organ and effective doses for a stylized phantom in the standard upright position with those for phantoms in realistic work postures. The articulated phantoms represent working positions including fully and half bent torsos with extended arms for both the male and female reference adults. Dose coefficients are compared for both the upright and bent positions across monoenergetic photon energies: 0.05, 0.1, 0.5, 1.0, and 5.0 MeV. Additionally, the organ doses are compared across the International Commission on Radiological Protection's standard external radiation exposure geometries: antero-posterior, postero-anterior, left and right lateral, and isotropic (AP, PA, LLAT, RLAT, and ISO). For the AP and PA irradiation geometries, differences in organ doses compared to the upright phantom become more profound with increasing bending angles and have doses largely overestimated for all organs except the brain in AP and bladder in PA. In LLAT and RLAT irradiation geometries, energy deposition for organs is more likely to be underestimated compared to the upright phantom, with no overall change despite increased bending angle. The ISO source geometry did not cause a significant difference in absorbed organ dose between the different phantoms, regardless of position. Organ and effective fluence-to-dose coefficients are tabulated. In the AP geometry, the effective dose at the 45 bent position is overestimated compared to the upright phantom below 1 MeV by as much as 27% and 82% in the

Gauge invariance and canonical quantization applied in the study of internal structure of gauge field systems

International Nuclear Information System (INIS)

Wang Fan; Chen Xiangsong; Lue Xiaofu; Sun Weiming; Goldman, T.

2010-01-01

It is unavoidable to deal with the quark and gluon momentum and angular momentum contributions to the nucleon momentum and spin in the study of nucleon internal structure. However, we never have the quark and gluon momentum, orbital angular momentum and gluon spin operators which satisfy both the gauge invariance and the canonical momentum and angular momentum commutation relations. The conflicts between the gauge invariance and canonical quantization requirement of these operators are discussed. A new set of quark and gluon momentum, orbital angular momentum and spin operators, which satisfy both the gauge invariance and canonical momentum and angular momentum commutation relations, are proposed. The key point to achieve such a proper decomposition is to separate the gauge field into the pure gauge and the gauge covariant parts. The same conflicts also exist in QED and quantum mechanics and have been solved in the same manner. The impacts of this new decomposition to the nucleon internal structure are discussed.

A natural Poincare gauge model

International Nuclear Information System (INIS)

Aldrovandi, R.; Pereira, J.G.

1985-01-01

A natural candidate model for a gauge theory for the Poincare group is discussed. It satisfies the usual electric-magnetic symmetry of gauge models and is a contraction of a gauge model for the De Sitter group. Its field equations are just the Yang-Mills equations for the Poincare group. It is shown that these equations do not follow from a Lagrangean. (Author) [pt

Gauge bridges in classical field theory

International Nuclear Information System (INIS)

Jakobs, S.

2009-03-01

In this thesis Poisson structures of two classical gauge field theories (Maxwell-Klein-Gordon- and Maxwell-Dirac-system) are constructed using the parametrix construction of Green's functions. Parametrices for the Maxwell-Klein-Gordon- and Maxwell-Dirac-system are constructed in Minkowski space and this construction is later generalized to curved space times for the Maxwell-Klein-Gordon-system. With these Green's functions Poisson brackets will be defined as Peierls brackets. Finally non-local, gauge invariant observables, the so-called ''gauge bridges''are constructed. Gauge bridges are the matrix elements of holonomy operators. It is shown, that these emerge from Poisson brackets of local, gauge invariant observables. (orig.)

Lattice gauge theory using parallel processors

International Nuclear Information System (INIS)

Lee, T.D.; Chou, K.C.; Zichichi, A.

1987-01-01

The book's contents include: Lattice Gauge Theory Lectures: Introduction and Current Fermion Simulations; Monte Carlo Algorithms for Lattice Gauge Theory; Specialized Computers for Lattice Gauge Theory; Lattice Gauge Theory at Finite Temperature: A Monte Carlo Study; Computational Method - An Elementary Introduction to the Langevin Equation, Present Status of Numerical Quantum Chromodynamics; Random Lattice Field Theory; The GF11 Processor and Compiler; and The APE Computer and First Physics Results; Columbia Supercomputer Project: Parallel Supercomputer for Lattice QCD; Statistical and Systematic Errors in Numerical Simulations; Monte Carlo Simulation for LGT and Programming Techniques on the Columbia Supercomputer; Food for Thought: Five Lectures on Lattice Gauge Theory

Systematics of higher-spin gauge fields

International Nuclear Information System (INIS)

de Wit, B.; Freedman, D.Z.

1980-01-01

Free-field theories for symmetric tensor and tensor-spinor gauge fields have recently been obtained which describe massless particles of arbitrary integer or half-integer spin. An independent discussion of these field theories is given here, based on a hierarchy of generalized Christoffel symbols with simple gauge transformation properties. The necessity of certain constraints on gauge fields and parameters is easily seen. Wave equations and Lagrangians are expressed in terms of the Christoffel symbols, and the independent modes of the system are counted in covariant gauges. Minimal-coupling inconsistency and a combined system of higher-spin boson gauge fields interacting with relativistic particles is discussed

Measuring the x-ray resolving power of bent potassium acid phthalate diffraction crystals

International Nuclear Information System (INIS)

Haugh, M. J.; Jacoby, K. D.; Wu, M.; Loisel, G. P.

2014-01-01

This report presents the results from measuring the X-ray resolving power of a curved potassium acid phthalate (KAP(001)) spectrometer crystal using two independent methods. It is part of a continuing effort to measure the fundamental diffraction properties of bent crystals that are used to study various characteristics of high temperature plasmas. Bent crystals like KAP(001) do not usually have the same diffraction properties as corresponding flat crystals. Models that do exist to calculate the effect of bending the crystal on the diffraction properties have simplifying assumptions and their accuracy limits have not been adequately determined. The type of crystals that we measured is being used in a spectrometer on the Z machine at Sandia National Laboratories in Albuquerque, New Mexico. The first technique for measuring the crystal resolving power measures the X-ray spectral line width of the characteristic lines from several metal anodes. The second method uses a diode X-ray source and a double crystal diffractometer arrangement to measure the reflectivity curve of the KAP(001) crystal. The width of that curve is inversely proportional to the crystal resolving power. The measurement results are analyzed and discussed

Measuring the x-ray resolving power of bent potassium acid phthalate diffraction crystals

Energy Technology Data Exchange (ETDEWEB)

Haugh, M. J., E-mail: haughmj@nv.doe.gov; Jacoby, K. D. [National Security Technologies, LLC, Livermore, California 94550 (United States); Wu, M.; Loisel, G. P. [Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States)

2014-11-15

This report presents the results from measuring the X-ray resolving power of a curved potassium acid phthalate (KAP(001)) spectrometer crystal using two independent methods. It is part of a continuing effort to measure the fundamental diffraction properties of bent crystals that are used to study various characteristics of high temperature plasmas. Bent crystals like KAP(001) do not usually have the same diffraction properties as corresponding flat crystals. Models that do exist to calculate the effect of bending the crystal on the diffraction properties have simplifying assumptions and their accuracy limits have not been adequately determined. The type of crystals that we measured is being used in a spectrometer on the Z machine at Sandia National Laboratories in Albuquerque, New Mexico. The first technique for measuring the crystal resolving power measures the X-ray spectral line width of the characteristic lines from several metal anodes. The second method uses a diode X-ray source and a double crystal diffractometer arrangement to measure the reflectivity curve of the KAP(001) crystal. The width of that curve is inversely proportional to the crystal resolving power. The measurement results are analyzed and discussed.

Suppression of surface effect by using bent-perfect-crystal monochromator in residual strain scanning

Czech Academy of Sciences Publication Activity Database

Vrána, Miroslav; Mikula, Pavol

490/491, - (2005), s. 234-238 ISSN 0255-5476 R&D Projects: GA ČR GA202/03/0891; GA AV ČR KSK1010104 Institutional research plan: CEZ:AV0Z1048901 Keywords : neutron diffraction * residual strain scanning * bent monochromator Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.399, year: 2005

In vivo longitudinal micro-CT study of bent long limb bones in rat offspring.

Science.gov (United States)

De Schaepdrijver, Luc; Delille, Peter; Geys, Helena; Boehringer-Shahidi, Christian; Vanhove, Christian

2014-07-01

Micro-computed X-ray tomography (micro-CT) has been reported as a reliable method to assess ex vivo rat and rabbit fetal skeletons in embryo-fetal developmental toxicity studies. Since micro-CT is a non-invasive imaging modality it has the potential for longitudinal, in vivo investigation of postnatal skeletal development. This is the first paper using micro-CT to assess the reversibility of drug-induced bent long bones in a longitudinal study from birth to early adulthood in rat offspring. Analysis of the scans obtained on postnatal Day 0, 7, 21 and 80 showed complete recovery or repair of the bent long limb bones (including the scapula) within the first 3 weeks. When assessing risk the ability to demonstrate recovery is highly advantageous when interpreting such transient skeletal change. In summary, in vivo micro-CT of small laboratory animals can aid in non-clinical safety assessment, particularly for specific mechanistic purposes or to address a particular concern in developmental biology. Copyright © 2014 Elsevier Inc. All rights reserved.

Microcomputerized neutron moisture gauge

International Nuclear Information System (INIS)

Liu Shengkang; Mei Yu

1987-01-01

A microcomputerized neutron moisture gauge is introduced. This gauge consists of a neutron moisture sensor and instruments. It is developed from the neutron moisture gauge for concrete mixer. A TECH-81 single card microcomputer is used for count, computation and display. It has the function of computing compensated quantity of sand. It can acquire the data from several neutron sensors by the multichanneling sampling, therefore it can measure moisture values of sand in several hoppers simultaneously. The precision of the static state calibration curve is 0.24% wt. The error limits of the dynamic state check is < 0.50% wt

Riot at the calc exam and other mathematically bent stories

CERN Document Server

Adams, Colin

2009-01-01

What's so funny about math? Lots! Especially if you're mathematically bent. In the world of Colin Adams, differential equations bring on tears of laughter. Hollywood producers hire algebraic geometers to punch up a script. In this world, math and humor are synonymous. Riot at the Calc Exam is a proof of this fact. A collection of humorous math stories, this book gives a window into mathematics and the culture of mathematicians. Appropriate for mathematicians, math students, math teachers, lay people with an interest in mathematics, and indeed everyone else. This book is a romp through the wild

Gauge and non-gauge curvature tensor copies

International Nuclear Information System (INIS)

Srivastava, P.P.

1982-10-01

A procedure for constructing curvature tensor copies is discussed using the anholonomic geometrical framework. The corresponding geometries are compared and the notion of gauge copy is elucidated. An explicit calculation is also made. (author)

Quantum gauge freedom in very special relativity

Energy Technology Data Exchange (ETDEWEB)

Upadhyay, Sudhaker, E-mail: sudhakerupadhyay@gmail.com [Centre for Theoretical Studies, Indian Institute of Technology Kharagpur, Kharagpur-721302, West Bengal (India); Panigrahi, Prasanta K., E-mail: pprasanta@iiserkol.ac.in [Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal (India)

2017-02-15

We demonstrate Yokoyama gaugeon formalism for the Abelian one-form gauge (Maxwell) as well as for Abelian two-form gauge theory in the very special relativity (VSR) framework. In VSR scenario, the extended action due to introduction of gaugeon fields also possesses form invariance under quantum gauge transformations. It is observed that the gaugeon field together with gauge field naturally acquire mass, which is different from the conventional Higgs mechanism. The quantum gauge transformation implements a shift in gauge parameter. Further, we analyze the BRST symmetric gaugeon formalism in VSR which embeds only one subsidiary condition rather than two.

Perturbative formulation of pure space-like axial gauge QED with infrared divergences regularized by residual gauge fields

International Nuclear Information System (INIS)

Nakawaki, Yuji; McCartor, Gary

2006-01-01

We construct a new perturbative formulation of pure space-like axial gauge QED in which the inherent infrared divergences are regularized by residual gauge fields. For this purpose, we carry out our calculations in the coordinates x μ =(x + , x - , x 1 , x 2 ), where x + =x 0 sinθ + x 3 cosθ and x - = x 0 cosθ - x 3 sinθ. Here, A=A 0 cosθ + A 3 sinθ = n·A=0 is taken as the gauge fixing condition. We show in detail that, in perturbation theory, infrared divergences resulting from the residual gauge fields cancel infrared divergences resulting from the physical parts of the gauge field. As a result, we obtain the gauge field propagator proposed by Mandelstam and Leibbrandt. By taking the limit θ→π/4, we are able to construct a light-cone formulation that is free from infrared divergences. With that analysis complete, we next calculate the one-loop electron self-energy, something not previously done in the light-cone quantization and light-cone gauge. (author)

Análisis de la biodiversidad de macroinvertebrados bentónicos del río Cunas mediante indicadores ambientales, Junín-Perú

Directory of Open Access Journals (Sweden)

María Custodio Villanueva

2016-01-01

Full Text Available El objetivo de la investigación fue analizar el estado de la biodiversidad de macroinvertebrados bentónicos del río Cunas mediante indicadores ambientales. Se definieron tres sectores de muestreo en dos épocas contrastantes. La valoración de las presiones antrópicas se realizó mediante la determinación de la carga de DBO5 aportada por aguas residuales. Se colectaron muestras de agua para la determinación de nitratos, fosfatos y coliformes termotolerantes. Los indicadores medidos in situ fueron: oxígeno disuelto, sólidos totales disueltos, conductividad, temperatura, pH y turbidez. Las muestras de macroinvertebrados bentónicos se colectaron utilizando una red Surber con malla de 250 μm de abertura. Los resultados de la presión antrópica sobre los macroinvertebrados bentónicos fueron: media de DBO5 de aguas residuales de la actividad piscícola 7,70 mg/L, de la actividad pecuaria 869 mg/L y de la actividad urbana 428,3 mg/L. Los resultados de los indicadores físico-químicos y bacteriológicos mostraron diferencias significativas para la conductividad, temperatura y sólidos totales disueltos. Se identificaron cuatro phyla, siete clases, 12 órdenes y 26 familias de macroinvertebrados bentónicos. Se concluye que las descargas de aguas residuales de las actividades pecuaria y urbana son presiones antrópicas significativas sobre la biodiversidad de macroinvertebrados bentónicos. Los indicadores fisicoquímicos y bacteriológicos de la calidad del agua determinados, según sector y época de muestreo, están en el rango de los ECA para agua de ríos de la sierra. La riqueza, abundancia y diversidad de macroinvertebrados bentónicos, según sector y época de muestreo, presentaron diferencias significativas.

Gauge theory and gravitation

International Nuclear Information System (INIS)

Kikkawa, Keiji; Nakanishi, Noboru; Nariai, Hidekazu

1983-01-01

These proceedings contain the articles presented at the named symposium. They deal with geometrical aspects of gauge theory and gravitation, special problems in gauge theories, quantum field theory in curved space-time, quantum gravity, supersymmetry including supergravity, and grand unification. See hints under the relevant topics. (HSI)

Thermal rate coefficients in collinear versus bent transition state reactions: the N+N{sub 2} case study

Energy Technology Data Exchange (ETDEWEB)

Lagana, Antonio; Faginas Lago, Noelia; Rampino, Sergio [Dipartimento di Chimica, Universita di Perugia, 06123 Perugia (Italy); Huarte-Larranaga, FermIn [Computer Simulation and Modeling Lab (CoSMoLab), Parc CientIfic de Barcelona, 08028 Barcelona (Spain); GarcIa, Ernesto [Departamento de Quimica Fisica, Universidad del PaIs Vasco, 01006 Vitoria (Spain)], E-mail: lagana05@gmail.com, E-mail: fhuarte@pcb.ub.es, E-mail: e.garcia@ehu.es

2008-10-15

Zero total angular momentum exact quantum calculations of the probabilities of the N+N{sub 2} reaction have been performed on the L3 potential energy surface having a bent transition state. This has allowed us to work out J-shifting estimates of the thermal rate coefficient based on the calculation of either detailed (state-to-state) or cumulative (multiconfiguration) probabilities. The results obtained are used to compare the numerical outcomes and the concurrent computational machineries of both quantum and semiclassical approaches as well as to exploit the potentialities of the J-shifting model. The implications of moving the barrier to reaction from the previously proposed collinear geometry of the LEPS to the bent one of L3 are also investigated by comparing the related detailed reactive probabilities.

Gauge-Higgs Unification Models in Six Dimensions with S2/Z2 Extra Space and GUT Gauge Symmetry

Directory of Open Access Journals (Sweden)

Cheng-Wei Chiang

2012-01-01

Full Text Available We review gauge-Higgs unification models based on gauge theories defined on six-dimensional spacetime with S2/Z2 topology in the extra spatial dimensions. Nontrivial boundary conditions are imposed on the extra S2/Z2 space. This review considers two scenarios for constructing a four-dimensional theory from the six-dimensional model. One scheme utilizes the SO(12 gauge symmetry with a special symmetry condition imposed on the gauge field, whereas the other employs the E6 gauge symmetry without requiring the additional symmetry condition. Both models lead to a standard model-like gauge theory with the SU(3×SU(2L×U(1Y(×U(12 symmetry and SM fermions in four dimensions. The Higgs sector of the model is also analyzed. The electroweak symmetry breaking can be realized, and the weak gauge boson and Higgs boson masses are obtained.

Tracking gauge symmetry factorizability on intervals

International Nuclear Information System (INIS)

Ngoc-Khanh Tran

2006-01-01

We track the gauge symmetry breaking pattern by boundary conditions on fifth and higher-dimensional intervals. It is found that, with Dirichlet-Neumann boundary conditions, the Kaluza-Klein decomposition in five-dimension for arbitrary gauge group can always be factorized into that for separate subsets of at most two gauge symmetries, and so is completely solvable. Accordingly, we present a simple and systematic geometric method to unambiguously identify the gauge breaking/mixing content by general set of Dirichlet-Neumann boundary conditions. We then formulate a limit theorem on gauge symmetry factorizability to recapitulate this interesting feature. Albeit the breaking/mixing, a particularly simple check of orthogonality and normalization of fields' modes in effective 4-dim picture is explicitly obtained. An interesting chained-mixing of gauge symmetries in higher dimensions by Dirichlet-Neumann boundary conditions is also explicitly constructed. This study has direct applications to higgsless/GUT model building

Factorization in QCD in Feynman gauge

International Nuclear Information System (INIS)

Tucci, R.R.

1985-01-01

We present a mass divergence power counting technique for QCD in the Feynman gauge. For the process γ/sup */ → qq, we find the leading regions of integration and show that single diagrams are at worst logarithmically divergent. Using the Weyl representation facilities the γ matrix manipulations necessary for power counting and adds much physical insight. We prove Ward type identities which are needed in the proof of factorization of the Drill Yan process. Previous treatments prove them only for an axial gauge, and the proofs are diagrammatic in nature. We, on the other hand, establish the identities for the Feynman gauge and through symmetry considerations at the Lagrangian level. The strategy is to first derive exact results in a background field gauge and then to show that to leading order in the mass divergences the background field gauge results can be used in the Feynman gauge

Gauge coupling unification in six dimensions

Energy Technology Data Exchange (ETDEWEB)

Lee, H.M. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)]|[Carnegie-Mellon Univ., Pittsburgh, PA (United States). Dept. of Physics

2006-11-15

We compute the one-loop gauge couplings in six-dimensional non-Abelian gauge theories on the T{sup 2}/Z{sub 2} orbifold with general GUT breaking boundary conditions. For concreteness, we apply the obtained general formulae to the gauge coupling running in a 6D SO(10) orbifold GUT where the GUT group is broken down to the standard model gauge group up to an extra U(1). We find that the one-loop corrections depend on the parity matrices encoding the orbifold boundary conditions as well as the volume and shape moduli of extra dimensions. When the U(1) is broken by the VEV of bulk singlets, the accompanying extra color triplets also affect the unification of the gauge couplings. In this case, the B-L breaking scale is closely linked to the compactification scales for maintaining a success of the gauge coupling unification. (orig.)

Hidden QCD in Chiral Gauge Theories

DEFF Research Database (Denmark)

Ryttov, Thomas; Sannino, Francesco

2005-01-01

The 't Hooft and Corrigan-Ramond limits of massless one-flavor QCD consider the two Weyl fermions to be respectively in the fundamental representation or the two index antisymmetric representation of the gauge group. We introduce a limit in which one of the two Weyl fermions is in the fundamental...... representation and the other in the two index antisymmetric representation of a generic SU(N) gauge group. This theory is chiral and to avoid gauge anomalies a more complicated chiral theory is needed. This is the generalized Georgi-Glashow model with one vector like fermion. We show that there is an interesting...... phase in which the considered chiral gauge theory, for any N, Higgses via a bilinear condensate: The gauge interactions break spontaneously to ordinary massless one-flavor SU(3) QCD. The additional elementary fermionic matter is uncharged under this SU(3) gauge theory. It is also seen that when...

Higgs phase in non-Abelian gauge theories

International Nuclear Information System (INIS)

Kaymakcalan, O.S.

1981-06-01

A non-Abelian gauge theory involving scalar fields with non-tachyonic mass terms in the Lagrangian is considered, in order to construct a finite energy density trial vacuum for this theory. The usual scalar potential arguments suggest that the vacuum of such a theory would be in the perturbative phase. However, the obvious choices for a vacuum in this phase, the Axial gauge and the Coulomb gauge bare vacua, do not have finite energy densities even with an ultraviolet cutoff. Indeed, it is a non-trivial problem to construct finite energy density vacua for non-Abelian gauge theories and this is intimately connected with the gauge fixing degeneracies of these theories. Since the gauge fixing is achieved in the Unitary gauge, this suggests that the Unitary gauge bare vacuum might be a finite energy trial vacuum and, despite the form of the scalar potential, the vacuum of this theory might be in a Higgs phase rather than the perturbative phase

Invariant gauge families inherent in Abelian-gauge field theory. [Scalar dipole ghost field, free-field equations

Energy Technology Data Exchange (ETDEWEB)

Yokoyama, Kan-ichi; Kubo, Reijiro

1974-12-01

The framework of the Nakanishi-Lautrup formalism should be enlarged by introducing a scalar dipole ghost field B(x), which is called gauge on field, together with its pair field. By taking free Lagrangian density, Free-field equations can be described. The vacuum is defined by using a neutral vector field U..mu..(x). The state-vector space is generated by the adjoining conjugates of U..mu..sup((+))(x), and auxiliary fields B(x), B/sub 1/(x) and B/sub 2/(x), which were introduced in the form of the Lagrangian density. The physical states can be defined by the supplementary conditions of the form B/sub 1/sup((+))(x) 1 phys>=B/sub 2/sup((+))(x) 1 phys>=0. It is seen that all the field equations and all the commutators are kept form-invariant, and that the gauge parameter ..cap alpha.. is transformed into ..cap alpha..' given by ..cap alpha..'=..cap alpha..+lambda, with epsilon unchanged. The Lagrangian density is specified only by the gauge invariant parameter epsilon. The gauge structure of theory has universal meaning over whole Abelian-gauge field. C-number gauge transformation and the gauge structure in the presence of interaction are also discussed.

Gauge-free gyrokinetic theory

Science.gov (United States)

Burby, Joshua; Brizard, Alain

2017-10-01

Test-particle gyrocenter equations of motion play an essential role in the diagnosis of turbulent strongly-magnetized plasmas, and are playing an increasingly-important role in the formulation of kinetic-gyrokinetic hybrid models. Previous gyrocenter models required the knowledge of the perturbed electromagnetic potentials, which are not directly observable quantities (since they are gauge-dependent). A new gauge-free formulation of gyrocenter motion is presented, which enables gyrocenter trajectories to be determined using only measured values of the directly-observable electromagnetic field. Our gauge-free gyrokinetic theory is general enough to allow for gyroradius-scale fluctuations in both the electric and magnetic field. In addition, we provide gauge-free expressions for the charge and current densities produced by a distribution of gyrocenters, which explicitly include guiding-center and gyrocenter polarization and magnetization effects. This research was supported by the U.S. DOE Contract Nos. DE-SC0014032 (AB) and DE-AC05-06OR23100 (JB).

Spontaneous emergence of gauge symmetry

International Nuclear Information System (INIS)

Nielsen, H.B.; Brene, N.

1987-05-01

Within the framework of the random dynamics project we have demonstrated several mechanisms for breakdown of a preexisting exact gauge symmetry. This note concerns and reviews a mechanism which works essentially in the opposite direction, leading from am accidental approximate symmetry to an exact formal gauge symmetry. It was shown that although this symmetry is a priori only strictly formal, it can under certain circumstances lead to a physical consequence: the corresponding gauge boson becomes massless. In the chaotic models typical for our random dynamics project there is, of course, a strong competition between this mechanism and mechanisms which temd to destroy the symmetry and give mass(es) to the gauge boson(s). (orig.)

Radioactive thickness gauge (1962); Jauge d'epaisseur radioactive (1962)

Energy Technology Data Exchange (ETDEWEB)

Guizerix, J. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1962-07-01

The author describes a thickness gauge in which the scintillating crystal detector alternately 'sees' a radioactive source through the material which is to be measured and then a control source of the same material; the radiations are separated in time by an absorbing valve whose sections are alternately full and hollow. The currents corresponding to the two sources are separated beyond the photomultiplier tube by a detector synchronized with the rotation of the valve. The quotient of these two currents is then obtained with a standard recording potentiometer. It is found that the average value of the response which is in the form G = f(I{sub 1}/I{sub 2}) is not affected by decay of the radioactive sources, and that it is little influenced by variations of high tension, temperature, or properties of the air in the source detector interval. The performance of the gauge is given. (author) [French] L'auteur decrit une jauge d'epaisseur dans laquelle le cristal scintillant detecteur 'voit' alternativement une source radioactive a travers le materiau a mesurer, puis une source de reference de meme nature; la separation des rayonnements est faite dans le temps a l'aide d'un volet absorbeur a secteurs alternativement pleins et creux. Les courants correspondants aux deux sources sont separes apres le tube photomultiplicateur par un detecteur synchrone avec la rotation du volet. On fait ensuite le quotient de ces deux courants a l'aide d'un potientometre enregistreur classique. il resulte de cette disposition que la valeur moyenne de la reponse, qui est de la forme G = f(I{sub 1}/I{sub 2}) n'est pas affectee par la decroissance des sources radioactives, et qu'elle est peu sensible aux variations de haute tension, de temperature ou des proprietes de l'air dans l'intervalle source-detecteur. On donne les performances de cette jauge. (auteur)

Convexity, gauge-dependence and tunneling rates

Energy Technology Data Exchange (ETDEWEB)

Plascencia, Alexis D.; Tamarit, Carlos [Institute for Particle Physics Phenomenology, Durham University,South Road, DH1 3LE (United Kingdom)

2016-10-19

We clarify issues of convexity, gauge-dependence and radiative corrections in relation to tunneling rates. Despite the gauge dependence of the effective action at zero and finite temperature, it is shown that tunneling and nucleation rates remain independent of the choice of gauge-fixing. Taking as a starting point the functional that defines the transition amplitude from a false vacuum onto itself, it is shown that decay rates are exactly determined by a non-convex, false vacuum effective action evaluated at an extremum. The latter can be viewed as a generalized bounce configuration, and gauge-independence follows from the appropriate Nielsen identities. This holds for any election of gauge-fixing that leads to an invertible Faddeev-Popov matrix.

On behaviour of Weyl's gauge field

International Nuclear Information System (INIS)

Yuan Zhong Zhang.

1990-05-01

We consider a system, consisting of a metric tensor g μυ , a scalar field φ, a Weyl's gauge field A μ and a scalar matter field Φ, which is invariant under general coordinate transformation and Weyl's gauge transformation. Two kinds of identities and field equations are given and discussed. A special space-time with g μυ =φ -2 η μυ is considered in a gauge-independent manner. We point out that in a correct treatment where g μυ is not regarded as an independent variable, an auxiliary condition for Weyl's gauge field cannot be obtained. Therefore Weyl's gauge field can be treated as a usual field of positive norm. (author). 11 refs

Convexity, gauge-dependence and tunneling rates

International Nuclear Information System (INIS)

Plascencia, Alexis D.; Tamarit, Carlos

2016-01-01

We clarify issues of convexity, gauge-dependence and radiative corrections in relation to tunneling rates. Despite the gauge dependence of the effective action at zero and finite temperature, it is shown that tunneling and nucleation rates remain independent of the choice of gauge-fixing. Taking as a starting point the functional that defines the transition amplitude from a false vacuum onto itself, it is shown that decay rates are exactly determined by a non-convex, false vacuum effective action evaluated at an extremum. The latter can be viewed as a generalized bounce configuration, and gauge-independence follows from the appropriate Nielsen identities. This holds for any election of gauge-fixing that leads to an invertible Faddeev-Popov matrix.

Gauge theories and their superspace quantization

International Nuclear Information System (INIS)

Falck, N.K.

1984-01-01

In this thesis the mathematical formalism for gauge theory is treated together with its extensions to supersymmetry. After a description of the differential calculus in superspace, gauge theories at the classical level are considered. Then the superspace quantization of gauge theories is described. (HSI)

The cross-over points in lattice gauge theories with continuous gauge groups

International Nuclear Information System (INIS)

Cvitanovic, P.; Greensite, J.; Lautrup, B.

1981-01-01

We obtain a closed expression for the weak-to-strong coupling cross-over point in all Wilson type lattice gauge theories with continuous gauge groups. We use a weak-coupling expansion of the mean-field self-consistency equation. In all cases where our results can be compared with Monte Carlo calculations the agreement is excellent. (orig.)

S-duality in N = 4 supersymmetric gauge theories with arbitrary gauge group

International Nuclear Information System (INIS)

Dorey, Nicholas; Fraser, Christophe; Hollowood, Timothy J.; Kneipp, Marco A.C.

1996-12-01

The Goddard, Nuyts and Olive conjecture for electric-magnetic duality in the Yang-Mills theory with an arbitrary gauge group G is extended by including a non-vanishing vacuum angle θ. This extended S-duality conjecture includes the case when the unbroken gauge group in non-Abelian and a definite prediction for the spectrum of dyons results. (author)

Gauge-fixing ambiguity and monopole number

International Nuclear Information System (INIS)

Hioki, S.; Miyamura, O.

1991-01-01

Gauge-fixing ambiguities of lattice SU(2) QCD are studied in the maximally abelian and unitary gauges. In the former, we find local maxima of a gauge-fixing function which may correspond to Gribov copies. There is a definite anti-correlation between the number of monopoles and the value of the function. Errors of measured quantities coming from the ambiguity are found to be less than inherent dispersion in the ensemble average. No ambiguity is found in the unitary gauges. (orig.)

Bent CNN bond of diazo compounds, RR'(Cdbnd N+dbnd N-)

Science.gov (United States)

Akita, Motoko; Takahashi, Mai; Kobayashi, Keiji; Hayashi, Naoto; Tukada, Hideyuki

2013-02-01

The reaction of ninhydrin with benzophenone hydrazone afforded 2-diazo-3-diphenylmethylenehydrazono-1-indanone 1 and 2-diazo-1,3-bis(diphenylmethylenehydrazono)indan 2. X-ray crystal structure analyses of these products showed that the diazo functional group Cdbnd N+dbnd N- of 1 is bent by 172.9°, while that of 2 has a linear geometry. The crystal structure data of diazo compounds have been retrieved from the Cambridge Structural Database (CSD), which hit 177 entries to indicate that the angle of 172.9° in 1 lies in one of the most bent structures. The CSD search also indicated that diazo compounds consisting of a distorted diazo carbon tend to bend the Cdbnd N+dbnd N- bond. On the basis of DFT calculations (B3LYP/6-311++G(d,p)) of model compounds, it was revealed that the bending of the CNN bond is principally induced by steric factors and that the neighboring carbonyl group also plays a role in bending toward the carbonyl side owing to an electrostatic attractive interaction. The potential surface along the path of Cdbnd N+dbnd N- bending in 2-diazopropane shows a significantly shallow profile with only 4 kcal/mol needed to bend the Cdbnd N+dbnd N- bond from 180° to 160°. Thus, the bending of the diazo group in 1 is reasonable as it is provided with all of the factors for facile bending disclosed in this investigation.

Comparison of coupled mode theory and FDTD simulations of coupling between bent and straight optical waveguides

NARCIS (Netherlands)

Bertolotti, M.; Symes, W.W.; Stoffer, Remco; Hiremath, K.R.; Driessen, A.; Michelotti, F; Hammer, Manfred

Analysis of integrated optical cylindrical microresonators involves the coupling between a straight waveguide and a bent waveguide. Our (2D) variant of coupled mode theory is based on analytically represented mode profiles. With the bend modes expressed in Cartesian coordinates, coupled mode

Tracheal tube and laryngeal mask cuff pressure during anaesthesia - mandatory monitoring is in need

DEFF Research Database (Denmark)

Rokamp, K.Z.; Secher, N.H.; Møller, Ann

2010-01-01

ABSTRACT: BACKGROUND: To prevent endothelium and nerve lesions, tracheal tube and laryngeal mask cuff pressure is to be maintained at a low level and yet be high enough to secure air sealing. METHOD: In a prospective quality-control study, 201 patients undergoing surgery during anaesthesia (without...... the use of nitrous oxide) were included for determination of the cuff pressure of the tracheal tubes and laryngeal masks. RESULTS: In the 119 patients provided with a tracheal tube, the median cuff pressure was 30 (range 8 - 100) cm H2O and the pressure exceeded 30 cm H2O (upper recommended level) for 54...... patients. In the 82 patients provided with a laryngeal mask, the cuff pressure was 95 (10 - 121) cm H2O and above 60 cm H2O (upper recommended level) for 56 patients and in 34 of these patients, the pressure exceeded the upper cuff gauge limit (120 cm H2O). There was no association between cuff pressure...

Electrostatic potential in a bent piezoelectric nanowire with consideration of size-dependent piezoelectricity and semiconducting characterization

Science.gov (United States)

Wang, K. F.; Wang, B. L.

2018-06-01

Determining the electric potential in a bent piezoelectric nanowire (NW) is a fundamental issue of nanogenerators and nanopiezotronics. The combined influence of the flexoelectric effect, the semiconducting performance and the angle of atomic force microscope (AFM) tip has never been studied previously and will be investigated in this paper. The exact solution for the electric potential of a bent piezoelectric semiconductor NW is derived. The electric potential of the present model with consideration of flexoelectric effect varies along the length of the NW and is different from that of the classical piezoelectric model. Flexoelectric effect enhances but the semiconducting performance reduces the electric potential of the NW. In addition, it is found that if the angle of the AFM tip reaches 30°, the error of the electric potential obtained from the model ignored the effect of the angle of the AFM tip is almost 16%, which is unacceptable.

Precision contact level gauge

International Nuclear Information System (INIS)

Krejci, M.; Pilat, M.; Stulik, P.

1977-01-01

Equipment was developed measuring the heavy water level in the TR-0 reactor core within an accuracy of several hundredths of a millimeter in a range of around 3.5 m and at a temperature of up to 90 degC. The equipment uses a vibrating needle contact as a high sensitivity level gauge and a servomechanical system with a motion screw carrying the gauge for monitoring and measuring the level in the desired range. The advantage of the unique level gauge consists in that that the transducer converts the measured level position to an electric signal, ie., pulse width, with high sensitivity and without hysteresis. (Kr)

Gyrocenter-gauge kinetic theory

International Nuclear Information System (INIS)

Qin, H.; Tang, W.M.; Lee, W.W.

2000-01-01

Gyrocenter-gauge kinetic theory is developed as an extension of the existing gyrokinetic theories. In essence, the formalism introduced here is a kinetic description of magnetized plasmas in the gyrocenter coordinates which is fully equivalent to the Vlasov-Maxwell system in the particle coordinates. In particular, provided the gyroradius is smaller than the scale-length of the magnetic field, it can treat high frequency range as well as the usual low frequency range normally associated with gyrokinetic approaches. A significant advantage of this formalism is that it enables the direct particle-in-cell simulations of compressional Alfven waves for MHD applications and of RF waves relevant to plasma heating in space and laboratory plasmas. The gyrocenter-gauge kinetic susceptibility for arbitrary wavelength and arbitrary frequency electromagnetic perturbations in a homogeneous magnetized plasma is shown to recover exactly the classical result obtained by integrating the Vlasov-Maxwell system in the particle coordinates. This demonstrates that all the waves supported by the Vlasov-Maxwell system can be studied using the gyrocenter-gauge kinetic model in the gyrocenter coordinates. This theoretical approach is so named to distinguish it from the existing gyrokinetic theory, which has been successfully developed and applied to many important low-frequency and long parallel wavelength problems, where the conventional meaning of gyrokinetic has been standardized. Besides the usual gyrokinetic distribution function, the gyrocenter-gauge kinetic theory emphasizes as well the gyrocenter-gauge distribution function, which sometimes contains all the physics of the problems being studied, and whose importance has not been realized previously. The gyrocenter-gauge distribution function enters Maxwell's equations through the pull-back transformation of the gyrocenter transformation, which depends on the perturbed fields. The efficacy of the gyrocenter-gauge kinetic approach is

Channeling and radiation in periodically bent crystals

CERN Document Server

Korol, Andrey V; Greiner, Walter

2014-01-01

The development of coherent radiation sources for sub-angstrom wavelengths - i.e. in the hard X-ray and gamma-ray range -  is a challenging goal of modern physics. The availability of such sources will have many applications in basic science, technology and medicine, and, in particular, they may have a revolutionary impact on nuclear and solid state physics, as well as on the life sciences. The present state-of-the-art lasers are capable of emitting electromagnetic radiation from the infrared to the ultraviolet, while free electron lasers (X-FELs) are now entering the soft X-ray region. Moving further, i.e. into the hard X and/or gamma ray band, however, is not possible without new approaches and technologies.   In this book we introduce and discuss one such novel approach -the radiation formed in a Crystalline Undulator - whereby electromagnetic radiation is generated by a bunch of ultra-relativistic particles channeling through a periodically bent crystalline structure. Under certain conditions, such a d...

27 CFR 19.768 - Gauge record.

Science.gov (United States)

2010-04-01

... or warehouseman; and (j) Gauge data: (1) Package identification, tank number, volumetric or weight... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Gauge record. 19.768... OF THE TREASURY LIQUORS DISTILLED SPIRITS PLANTS Records and Reports Other Records § 19.768 Gauge...

Maximal Abelian gauge and a generalized BRST transformation

Directory of Open Access Journals (Sweden)

Shinichi Deguchi

2016-05-01

Full Text Available We apply a generalized Becchi–Rouet–Stora–Tyutin (BRST formulation to establish a connection between the gauge-fixed SU(2 Yang–Mills (YM theories formulated in the Lorenz gauge and in the Maximal Abelian (MA gauge. It is shown that the generating functional corresponding to the Faddeev–Popov (FP effective action in the MA gauge can be obtained from that in the Lorenz gauge by carrying out an appropriate finite and field-dependent BRST (FFBRST transformation. In this procedure, the FP effective action in the MA gauge is found from that in the Lorenz gauge by incorporating the contribution of non-trivial Jacobian due to the FFBRST transformation of the path integral measure. The present FFBRST formulation might be useful to see how Abelian dominance in the MA gauge is realized in the Lorenz gauge.

Anatomy education for the YouTube generation.

Science.gov (United States)

Barry, Denis S; Marzouk, Fadi; Chulak-Oglu, Kyrylo; Bennett, Deirdre; Tierney, Paul; O'Keeffe, Gerard W

2016-01-01

Anatomy remains a cornerstone of medical education despite challenges that have seen a significant reduction in contact hours over recent decades; however, the rise of the "YouTube Generation" or "Generation Connected" (Gen C), offers new possibilities for anatomy education. Gen C, which consists of 80% Millennials, actively interact with social media and integrate it into their education experience. Most are willing to merge their online presence with their degree programs by engaging with course materials and sharing their knowledge freely using these platforms. This integration of social media into undergraduate learning, and the attitudes and mindset of Gen C, who routinely creates and publishes blogs, podcasts, and videos online, has changed traditional learning approaches and the student/teacher relationship. To gauge this, second year undergraduate medical and radiation therapy students (n = 73) were surveyed regarding their use of online social media in relation to anatomy learning. The vast majority of students had employed web-based platforms to source information with 78% using YouTube as their primary source of anatomy-related video clips. These findings suggest that the academic anatomy community may find value in the integration of social media into blended learning approaches in anatomy programs. This will ensure continued connection with the YouTube generation of students while also allowing for academic and ethical oversight regarding the use of online video clips whose provenance may not otherwise be known. © 2015 American Association of Anatomists.

Chern-Simons gauge theory: Ten years after

International Nuclear Information System (INIS)

Labastida, J. M. F.

1999-01-01

A brief review on the progress made in the study of Chern-Simons gauge theory since its relation to knot theory was discovered ten years ago is presented. Emphasis is made on the analysis of the perturbative study of the theory and its connection to the theory of Vassiliev invariants. It is described how the study of the quantum field theory for three different gauge fixings leads to three different representations for Vassiliev invariants. Two of these gauge fixings lead to well known representations: the covariant Landau gauge corresponds to the configuration space integrals while the non-covariant light-cone gauge to the Kontsevich integral. The progress made in the analysis of the third gauge fixing, the non-covariant temporal gauge, is described in detail. In this case one obtains combinatorial expressions, instead of integral ones, for Vassiliev invariants. The approach based on this last gauge fixing seems very promising to obtain a full combinatorial formula. We collect the combinatorial expressions for all the Vassiliev invariants up to order four which have been obtained in this approach

Review of non-nuclear density gauges as possible replacements for ITD's nuclear density gauges.

Science.gov (United States)

2015-01-01

This report examines the possibility of replacing nuclear density gauges (NDGs) with non-nuclear density gauges (NNDGs) to : measure density of hot mix asphalt (HMA) and unbound pavement layers in the field. The research team evaluated the : effectiv...

Invariant structures in gauge theories and confinement

International Nuclear Information System (INIS)

Prokhorov, L.V.; Shabanov, S.V.

1991-01-01

The problem of finding all gauge invariants is considered in connection with the problem of confinement. Polylocal gauge tensors are introduced and studied. It is shown (both in physical and pure geometrical approaches) that the path-ordered exponent is the only fundamental bilocal gauge tensor, which means that any irreducible polylocal gauge tensor is built of P-exponents and local tensors (matter fields). The simplest invariant structures in electrodynamics, chromodynamics and a theory with the gauge group SU(2) are considered separately. 23 refs.; 2 figs

Improved Landau gauge fixing and discretisation errors

International Nuclear Information System (INIS)

Bonnet, F.D.R.; Bowman, P.O.; Leinweber, D.B.; Richards, D.G.; Williams, A.G.

2000-01-01

Lattice discretisation errors in the Landau gauge condition are examined. An improved gauge fixing algorithm in which O(a 2 ) errors are removed is presented. O(a 2 ) improvement of the gauge fixing condition displays the secondary benefit of reducing the size of higher-order errors. These results emphasise the importance of implementing an improved gauge fixing condition

Gauge-invariant cosmological density perturbations

International Nuclear Information System (INIS)

Sasaki, Misao.

1986-06-01

Gauge-invariant formulation of cosmological density perturbation theory is reviewed with special emphasis on its geometrical aspects. Then the gauge-invariant measure of the magnitude of a given perturbation is presented. (author)

Duffin-Kemmer formulation of gauge theories

International Nuclear Information System (INIS)

Okubo, S.; Tosa, Y.

1979-01-01

Gauge theories, including the Yang-Mills theory as well as Einstein's general relativity, are reformulated in first-order differential forms. In this generalized Duffin-Kemmer formalism, gauge theories take very simple forms with only cubic interactions. Moreover, every local gauge transformation, e.g., that of Yang and Mills or Einstein, etc., has an essentially similar form. Other examples comprise a gauge theory akin to the Sugawara theory of currents and the nonlinear realization of chiral symmetry. The octonion algebra is found possibly relevant to the discussion of the Yang-Mills theory

New gaugings and non-geometry

Energy Technology Data Exchange (ETDEWEB)

Lee, Kanghoon [Quantum Universe Center, Korea Institute for Advanced Study, Seoul (Korea, Republic of); Strickland-Constable, Charles [Institut de Physique Theorique, Universite Paris Saclay, CEA, CNRS, Gif-sur-Yvette (France); Waldram, Daniel [Department of Physics, Imperial College London (United Kingdom); Berkeley Center for Theoretical Physics, University of California, Berkeley, CA (United States)

2017-10-15

We discuss the possible realisation in string/M theory of the recently discovered family of four-dimensional maximal SO(8) gauged supergravities, and of an analogous family of seven-dimensional half-maximal SO(4) gauged supergravities. We first prove a no-go theorem that neither class of gaugings can be realised via a compactification that is locally described by ten- or eleven-dimensional supergravity. In the language of Double Field Theory and its M theory analogue, this implies that the section condition must be violated. Introducing the minimal number of additional coordinates possible, we then show that the standard S{sup 3} and S{sup 7} compactifications of ten- and eleven-dimensional supergravity admit a new class of section-violating generalised frames with a generalised Lie derivative algebra that reproduces the embedding tensor of the SO(4) and SO(8) gaugings respectively. The physical meaning, if any, of these constructions is unclear. They highlight a number of the issues that arise when attempting to apply the formalism of Double Field Theory to non-toroidal backgrounds. Using a naive brane charge quantisation to determine the periodicities of the additional coordinates restricts the SO(4) gaugings to an infinite discrete set and excludes all the SO(8) gaugings other than the standard one. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

New gaugings and non-geometry

International Nuclear Information System (INIS)

Lee, Kanghoon; Strickland-Constable, Charles; Waldram, Daniel

2017-01-01

We discuss the possible realisation in string/M theory of the recently discovered family of four-dimensional maximal SO(8) gauged supergravities, and of an analogous family of seven-dimensional half-maximal SO(4) gauged supergravities. We first prove a no-go theorem that neither class of gaugings can be realised via a compactification that is locally described by ten- or eleven-dimensional supergravity. In the language of Double Field Theory and its M theory analogue, this implies that the section condition must be violated. Introducing the minimal number of additional coordinates possible, we then show that the standard S 3 and S 7 compactifications of ten- and eleven-dimensional supergravity admit a new class of section-violating generalised frames with a generalised Lie derivative algebra that reproduces the embedding tensor of the SO(4) and SO(8) gaugings respectively. The physical meaning, if any, of these constructions is unclear. They highlight a number of the issues that arise when attempting to apply the formalism of Double Field Theory to non-toroidal backgrounds. Using a naive brane charge quantisation to determine the periodicities of the additional coordinates restricts the SO(4) gaugings to an infinite discrete set and excludes all the SO(8) gaugings other than the standard one. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Noncommutative gauge theories and Kontsevich's formality theorem

International Nuclear Information System (INIS)

Jurco, B.; Schupp, P.; Wess, J.

2001-01-01

The equivalence of star products that arise from the background field with and without fluctuations and Kontsevich's formality theorem allow an explicitly construction of a map that relates ordinary gauge theory and noncommutative gauge theory (Seiberg-Witten map.) Using noncommutative extra dimensions the construction is extended to noncommutative nonabelian gauge theory for arbitrary gauge groups; as a byproduct we obtain a 'Mini Seiberg-Witten map' that explicitly relates ordinary abelian and nonabelian gauge fields. All constructions are also valid for non-constant B-field, and even more generally for any Poisson tensor

Profile measurement of a bent neutron mirror using an ultrahigh precision non-contact measurement system with an auto focus laser probe

International Nuclear Information System (INIS)

Morita, S; Guo, J; Yamagata, Y; Yamada, N L; Torikai, N; Takeda, S; Furusaka, M

2016-01-01

A bent neutron mirror has been considered as one of the best solutions for focusing neutron beams from the viewpoint of cost-benefit performance. Although the form deviation of the bent profile is expected because of the large spot size, it is difficult to measure due to its geometric limitation. Here, we propose a non-contact measurement system using an auto focus (AF) laser probe on an ultrahigh precision machine tool to precisely evaluate the form deviation of the bent mirror. The AF laser probe is composed of a diode laser, a position sensitive sensor, a charge-coupled device (CCD) camera and a microscope objective lens which is actuated by an electromagnetic motor with 1 nm resolution for position sensing and control. The sensor enables a non-contact profile measurement of a high precision surface without any surface damage in contrast with contact-type ultrahigh precision coordinate measurement machines with ruby styli. In the on-machine measurement system, a personal computer simultaneously acquires a displacement signal from the AF laser probe and 3-axis positional coordinates of the ultrahigh machine tool branched between the linear laser scales and the numerical controller. The acquisition rate of the 4-axis positional data in 1 nm resolution is more than 10 Hz and the simultaneity between the axes is negligible. The profile of a neutron bent mirror was measured from a transparent side using the developed system, and the result proves that the form deviation of the mirror enlarged the the spot size of focused neuron beam. (paper)

Class of very simple gauge theories which remain renormalizable even in the limit of infinite gauge coupling constant

International Nuclear Information System (INIS)

Kaptanoglu, S.

1983-01-01

A class of local gauge theories based on compact semisimple Lie groups is studied in the limit of infinite gauge coupling constant (g = infinity). In general, in this limit, the gauge fields become auxiliary in all gauge theories, and the system develops a richer structure of constraints. Unfortunately for most gauge theories, this limit turns out to be too singular to quantize and the theory ceases to be renormalizable. For a special class of gauge theories, however, where there are no fermions and there is only one multiplet of scalars in the adjoint representation, we prove that a consistent renormalizable quantum theory exists even in this very singular limit. We trace this exceptional behavior to a new local translationlike symmetry in the functional space that this class of gauge models possesses in the limit of infinite gauge coupling constant. By carrying out the constraint analysis, evaluating the Faddeev-Popov-Senjanovic determinant, and doing the functional integrations over the canonical momenta, the gauge fields, and most of the components of the scalar fields, we obtain an extremely simple result with no non-Abelian structure left in it. For example, for the group SU(2), the final answer reduces to the theory of a one-component self-interacting real phi 4 scalar field theory. Throughout this paper, we use functional methods and make no approximations; our results are nonperturbative and exact. We also discuss some of the possible implications of our results

Digital lattice gauge theories

Science.gov (United States)

Zohar, Erez; Farace, Alessandro; Reznik, Benni; Cirac, J. Ignacio

2017-02-01

We propose a general scheme for a digital construction of lattice gauge theories with dynamical fermions. In this method, the four-body interactions arising in models with 2 +1 dimensions and higher are obtained stroboscopically, through a sequence of two-body interactions with ancillary degrees of freedom. This yields stronger interactions than the ones obtained through perturbative methods, as typically done in previous proposals, and removes an important bottleneck in the road towards experimental realizations. The scheme applies to generic gauge theories with Lie or finite symmetry groups, both Abelian and non-Abelian. As a concrete example, we present the construction of a digital quantum simulator for a Z3 lattice gauge theory with dynamical fermionic matter in 2 +1 dimensions, using ultracold atoms in optical lattices, involving three atomic species, representing the matter, gauge, and auxiliary degrees of freedom, that are separated in three different layers. By moving the ancilla atoms with a proper sequence of steps, we show how we can obtain the desired evolution in a clean, controlled way.

Dielectric lattice gauge theory

International Nuclear Information System (INIS)

Mack, G.

1983-06-01

Dielectric lattice gauge theory models are introduced. They involve variables PHI(b)epsilong that are attached to the links b = (x+esub(μ),x) of the lattice and take their values in the linear space g which consists of real linear combinations of matrices in the gauge group G. The polar decomposition PHI(b)=U(b)osub(μ)(x) specifies an ordinary lattice gauge field U(b) and a kind of dielectric field epsilonsub(ij)proportionalosub(i)osub(j)sup(*)deltasub(ij). A gauge invariant positive semidefinite kinetic term for the PHI-field is found, and it is shown how to incorporate Wilson fermions in a way which preserves Osterwalder Schrader positivity. Theories with G = SU(2) and without matter fields are studied in some detail. It is proved that confinement holds, in the sense that Wilson loop expectation values show an area law decay, if the Euclidean action has certain qualitative features which imply that PHI = 0 (i.e. dielectric field identical 0) is the unique maximum of the action. (orig.)

Dielectric lattice gauge theory

International Nuclear Information System (INIS)

Mack, G.

1984-01-01

Dielectric lattice gauge theory models are introduced. They involve variables PHI(b)element ofG that are attached to the links b = (x+esub(μ), x) of the lattice and take their values in the linear space G which consists of real linear combinations of matrices in the gauge group G. The polar decomposition PHI(b)=U(b)sigmasub(μ)(x) specifies an ordinary lattice gauge field U(b) and a kind of dielectric field epsilonsub(ij)proportional sigmasub(i)sigmasub(j)sup(*)deltasub(ij). A gauge invariant positive semidefinite kinetic term for the PHI-field is found, and it is shown how to incorporate Wilson fermions in a way which preserves Osterwalder-Schrader positivity. Theories with G = SU(2) and without matter fields are studied in some detail. It is proved that confinement holds, in the sense that Wilson-loop expectation values show an area law decay, if the euclidean action has certain qualitative features which imply that PHI=0 (i.e. dielectric field identical 0) is the unique maximum of the action. (orig.)

Stochastic quantization and gauge theories

International Nuclear Information System (INIS)

Kolck, U. van.

1987-01-01

Stochastic quantization is presented taking the Flutuation-Dissipation Theorem as a guide. It is shown that the original approach of Parisi and Wu to gauge theories fails to give the right results to gauge invariant quantities when dimensional regularization is used. Although there is a simple solution in an abelian theory, in the non-abelian case it is probably necessary to start from a BRST invariant action instead of a gauge invariant one. Stochastic regularizations are also discussed. (author) [pt

Singlet deflected anomaly/gauge mediation

International Nuclear Information System (INIS)

Blas, J. de; Delgado, A.

2012-01-01

We study an extension of the standard anomaly/gauge mediation scenario where the messenger fields have direct interactions with an extra gauge singlet. This realizes a phenomenologically viable NMSSM-like scenario free of the μ-b μ problem. Current cosmological constraints imply a small size for the anomaly-mediation contributions, unless some source of R-parity violation is permitted. In the latter case the allowed regions in the parameter space can be substantially larger than in the corresponding gauge-mediation scenario.

Dynamic equations for gauge-invariant wave functions

International Nuclear Information System (INIS)

Kapshaj, V.N.; Skachkov, N.B.; Solovtsov, I.L.

1984-01-01

The Bethe-Salpeter and quasipotential dynamic equations for wave functions of relative quark motion, have been derived. Wave functions are determined by the gauge invariant method. The V.A. Fock gauge condition is used in the construction. Despite the transl tional noninvariance of the gauge condition the standard separation of variables has been obtained and wave function doesn't contain gauge exponents

Gauge field condensation in geometric quantum chromodynamics

International Nuclear Information System (INIS)

Guendelman, E.I.

1991-09-01

In odd number of dimensions, it is possible to construct general covariant gauge theories, where the metric is not an independent variable, but local function of the gauge fields. Starting from standardly defined gauge theory, upon functional integration of some variables, we could end up with such moodels. For models with SU(2) and SU(3) symmetry in three dimensions, gauge field condensation take place in the vacuum, which is nevertheless homogeneous and isotropic up to a gauge transformation, provided the space is flat. Introducing Higgs fields that spontaneously break the gauge symmetry, we get a breakdown of the homogenity and isotropy of the vacuum. Finally, we discuss how some of this ideas can be generalized to four and other even dimensions. (author)

Renormalization of gauge theories

International Nuclear Information System (INIS)

Becchi, C.; Rouet, A.; Stora, R.

1975-04-01

Gauge theories are characterized by the Slavnov identities which express their invariance under a family of transformations of the supergauge type which involve the Faddeev Popov ghosts. These identities are proved to all orders of renormalized perturbation theory, within the BPHZ framework, when the underlying Lie algebra is semi-simple and the gauge function is chosen to be linear in the fields in such a way that all fields are massive. An example, the SU2 Higgs Kibble model is analyzed in detail: the asymptotic theory is formulated in the perturbative sense, and shown to be reasonable, namely, the physical S operator is unitary and independant from the parameters which define the gauge function [fr

Weighing Rain Gauge Recording Charts

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Weighing rain gauge charts record the amount of precipitation that falls at a given location. The vast majority of the Weighing Rain Gauge Recording Charts...

Symmetry breaking in gauge glasses

International Nuclear Information System (INIS)

Hansen, K.

1988-09-01

In order to explain why nature selects the gauge groups of the Standard Model, Brene and Nielsen have proposed a way to break gauge symmetry which does not rely on the existence of a Higgs field. The observed gauge groups will in this scheme appear as the only surviving ones when this mechanism is applied to a random selection of gauge groups. The essential assumption is a discrete space-time with random couplings. Some working assumptions were made for computational reasons of which the most important is that quantum fluctuations were neclected. This work presents an example which under the same conditions show that a much wider class of groups than predicted by Brene and Nielsen will be broken. In particular no possible Standard Model Group survives unbroken. Numerical calculations support the analytical result. (orig.)

Gauged supergravities in various spacetime dimensions

Energy Technology Data Exchange (ETDEWEB)

Weidner, M.

2006-12-15

In this thesis we study the gaugings of extended supergravity theories in various space-time dimensions. These theories describe the low-energy limit of non-trivial string compactifications. For each theory under consideration we work out all possible gaugings that are compatible with supersymmetry. They are parameterized by the so-called embedding tensor which is a group theoretical object that has to satisfy certain representation constraints. This embedding tensor determines all couplings in the gauged theory that are necessary to preserve gauge invariance and supersymmetry. The concept of the embedding tensor and the general structure of the gauged supergravities are explained in detail. The methods are then applied to the half-maximal (N=4) supergravities in d=4 and d=5 and to the maximal supergravities in d=2 and d=7. Examples of particular gaugings are given. Whenever possible, the higher-dimensional origin of these theories is identified and it is shown how the compactification parameters like fluxes and torsion are contained in the embedding tensor. (orig.)

Holographic gauge mediation via strongly coupled messengers

International Nuclear Information System (INIS)

McGuirk, Paul; Shiu, Gary; Sumitomo, Yoske

2010-01-01

We consider a relative of semidirect gauge mediation where the hidden sector exists at large 't Hooft coupling. Such scenarios can be difficult to describe using perturbative field theory methods but may fall into the class of holographic gauge mediation scenarios, meaning that they are amenable to the techniques of gauge/gravity duality. We use a recently found gravity solution to examine one such case, where the hidden sector is a cascading gauge theory resulting in a confinement scale not much smaller than the messenger mass. In the original construction of holographic gauge mediation, as in other examples of semidirect gauge mediation at strong coupling, the primary contributions to visible sector soft terms come from weakly coupled messenger mesons. In contrast to these examples, we describe the dual of a gauge theory where there are significant contributions from scales in which the strongly coupled messenger quarks are the effective degrees of freedom. In this regime, the visible sector gaugino mass can be calculated entirely from holography.

A lattice formulation of chiral gauge theories

International Nuclear Information System (INIS)

Bodwin, G.T.

1995-12-01

The authors present a method for formulating gauge theories of chiral fermions in lattice field theory. The method makes use of a Wilson mass to remove doublers. Gauge invariance is then restored by modifying the theory in two ways: the magnitude of the fermion determinant is replaced with the square root of the determinant for a fermion with vector-like couplings to the gauge field; a double limit is taken in which the lattice spacing associated with the fermion field is taken to zero before the lattice spacing associated with the gauge field. The method applies only to theories whose fermions are in an anomaly-free representation of the gauge group. They also present a related technique for computing matrix elements of operators involving fermion fields. Although the analyses of these methods are couched in weak-coupling perturbation theory, it is argued that computational prescriptions are gauge invariant in the presence of a nonperturbative gauge-field configuration

Analysis of algorithms for detection of resonance frequencies in vibration measurements on super heater tubes; Analys av algoritmer foer detektering av resonansfrekvenser i vibrationsmaetningar paa oeverhettartuber

Energy Technology Data Exchange (ETDEWEB)

Eriksson, Daniel

2010-07-01

Combustion of fuel in thermal power plants emits particles which creates coatings on the super heater tubes. The coatings isolate the tubes and impairs the efficiency of the heat transfer. Cleaning the tubes occurs while the power plant is running but without any knowledge of the actual coating. A change in frequency corresponds to a change in mass of the coatings. This thesis has been focusing in estimating resonance frequencies in vibration measurements made by strain gauges on the tubes. To improve the estimations a target tracking algorithm had been added. The results indicates that it is possible to estimate the resonance frequencies but the algorithms need to be verified on more signals.

True Tapping Mode Scanning Near-Field Optical Microscopy with Bent Glass Fiber Probes.

Science.gov (United States)

Smirnov, A; Yasinskii, V M; Filimonenko, D S; Rostova, E; Dietler, G; Sekatskii, S K

2018-01-01

In scanning near-field optical microscopy, the most popular probes are made of sharpened glass fiber attached to a quartz tuning fork (TF) and exploiting the shear force-based feedback. The use of tapping mode feedback could be preferable. Such an approach can be realized, for example, using bent fiber probes. Detailed analysis of fiber vibration modes shows that realization of truly tapping mode of the probe dithering requires an extreme caution. In case of using the second resonance mode, probes vibrate mostly in shear force mode unless the bending radius is rather small (ca. 0.3 mm) and the probe's tip is short. Otherwise, the shear force character of the dithering persists. Probes having these characteristics were prepared by irradiation of a tapered etched glass fiber with a CW CO 2 laser. These probes were attached to the TF in double resonance conditions which enables achieving significant quality factor (4000-6000) of the TF + probe system (Cherkun et al., 2006). We also show that, to achieve a truly tapping character, dithering, short, and not exceeding 3 mm lengths of a freestanding part of bent fiber probe beam should also be used in the case of nonresonant excitation.

True Tapping Mode Scanning Near-Field Optical Microscopy with Bent Glass Fiber Probes

Directory of Open Access Journals (Sweden)

A. Smirnov

2018-01-01

Full Text Available In scanning near-field optical microscopy, the most popular probes are made of sharpened glass fiber attached to a quartz tuning fork (TF and exploiting the shear force-based feedback. The use of tapping mode feedback could be preferable. Such an approach can be realized, for example, using bent fiber probes. Detailed analysis of fiber vibration modes shows that realization of truly tapping mode of the probe dithering requires an extreme caution. In case of using the second resonance mode, probes vibrate mostly in shear force mode unless the bending radius is rather small (ca. 0.3 mm and the probe’s tip is short. Otherwise, the shear force character of the dithering persists. Probes having these characteristics were prepared by irradiation of a tapered etched glass fiber with a CW CO2 laser. These probes were attached to the TF in double resonance conditions which enables achieving significant quality factor (4000–6000 of the TF + probe system (Cherkun et al., 2006. We also show that, to achieve a truly tapping character, dithering, short, and not exceeding 3 mm lengths of a freestanding part of bent fiber probe beam should also be used in the case of nonresonant excitation.

Lopsided Gauge Mediation

CERN Document Server

De Simone, Andrea; Giudice, Gian Francesco; Pappadopulo, Duccio; Rattazzi, Riccardo

2011-01-01

It has been recently pointed out that the unavoidable tuning among supersymmetric parameters required to raise the Higgs boson mass beyond its experimental limit opens up new avenues for dealing with the so called $\\mu$-$B_\\mu$ problem of gauge mediation. In fact, it allows for accommodating, with no further parameter tuning, large values of $B_\\mu$ and of the other Higgs-sector soft masses, as predicted in models where both $\\mu$ and $B_\\mu$ are generated at one-loop order. This class of models, called Lopsided Gauge Mediation, offers an interesting alternative to conventional gauge mediation and is characterized by a strikingly different phenomenology, with light higgsinos, very large Higgs pseudoscalar mass, and moderately light sleptons. We discuss general parametric relations involving the fine-tuning of the model and various observables such as the chargino mass and the value of $\\tan\\beta$. We build an explicit model and we study the constraints coming from LEP and Tevatron. We show that in spite of ne...

Gauging Variational Inference

Energy Technology Data Exchange (ETDEWEB)

Chertkov, Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ahn, Sungsoo [Korea Advanced Inst. Science and Technology (KAIST), Daejeon (Korea, Republic of); Shin, Jinwoo [Korea Advanced Inst. Science and Technology (KAIST), Daejeon (Korea, Republic of)

2017-05-25

Computing partition function is the most important statistical inference task arising in applications of Graphical Models (GM). Since it is computationally intractable, approximate methods have been used to resolve the issue in practice, where meanfield (MF) and belief propagation (BP) are arguably the most popular and successful approaches of a variational type. In this paper, we propose two new variational schemes, coined Gauged-MF (G-MF) and Gauged-BP (G-BP), improving MF and BP, respectively. Both provide lower bounds for the partition function by utilizing the so-called gauge transformation which modifies factors of GM while keeping the partition function invariant. Moreover, we prove that both G-MF and G-BP are exact for GMs with a single loop of a special structure, even though the bare MF and BP perform badly in this case. Our extensive experiments, on complete GMs of relatively small size and on large GM (up-to 300 variables) confirm that the newly proposed algorithms outperform and generalize MF and BP.

Lattice gauge theories

International Nuclear Information System (INIS)

Creutz, M.

1983-04-01

In the last few years lattice gauge theory has become the primary tool for the study of nonperturbative phenomena in gauge theories. The lattice serves as an ultraviolet cutoff, rendering the theory well defined and amenable to numerical and analytical work. Of course, as with any cutoff, at the end of a calculation one must consider the limit of vanishing lattice spacing in order to draw conclusions on the physical continuum limit theory. The lattice has the advantage over other regulators that it is not tied to the Feynman expansion. This opens the possibility of other approximation schemes than conventional perturbation theory. Thus Wilson used a high temperature expansion to demonstrate confinement in the strong coupling limit. Monte Carlo simulations have dominated the research in lattice gauge theory for the last four years, giving first principle calculations of nonperturbative parameters characterizing the continuum limit. Some of the recent results with lattice calculations are reviewed

Direct gauging of the Poincare group V. Group scaling, classical gauge theory, and gravitational corrections

International Nuclear Information System (INIS)

Edelen, D.G.B.

1986-01-01

Homogeneous scaling of the group space of the Poincare group, P 10 , is shown to induce scalings of all geometric quantities associated with the local action of P 10 . The field equations for both the translation and the Lorentz rotation compensating fields reduce to O(1) equations if the scaling parameter is set equal to the general relativistic gravitational coupling constant 8πGc -4 . Standard expansions of all field variables in power series in the scaling parameter give the following results. The zeroth-order field equations are exactly the classical field equations for matter fields on Minkowski space subject to local action of an internal symmetry group (classical gauge theory). The expansion process is shown to break P 10 -gauge covariance of the theory, and hence solving the zeroth-order field equations imposes an implicit system of P 10 -gauge conditions. Explicit systems of field equations are obtained for the first- and higher-order approximations. The first-order translation field equations are driven by the momentum-energy tensor of the matter and internal compensating fields in the zeroth order (classical gauge theory), while the first-order Lorentz rotation field equations are driven by the spin currents of the same classical gauge theory. Field equations for the first-order gravitational corrections to the matter fields and the gauge fields for the internal symmetry group are obtained. Direct Poincare gauge theory is thus shown to satisfy the first two of the three-part acid test of any unified field theory. Satisfaction of the third part of the test, at least for finite neighborhoods, seems probable

Two-parameter nonlinear spacetime perturbations: gauge transformations and gauge invariance

International Nuclear Information System (INIS)

Bruni, Marco; Gualtieri, Leonardo; Sopuerta, Carlos F

2003-01-01

An implicit fundamental assumption in relativistic perturbation theory is that there exists a parametric family of spacetimes that can be Taylor expanded around a background. The choice of the latter is crucial to obtain a manageable theory, so that it is sometime convenient to construct a perturbative formalism based on two (or more) parameters. The study of perturbations of rotating stars is a good example: in this case one can treat the stationary axisymmetric star using a slow rotation approximation (expansion in the angular velocity Ω), so that the background is spherical. Generic perturbations of the rotating star (say parametrized by λ) are then built on top of the axisymmetric perturbations in Ω. Clearly, any interesting physics requires nonlinear perturbations, as at least terms λΩ need to be considered. In this paper, we analyse the gauge dependence of nonlinear perturbations depending on two parameters, derive explicit higher-order gauge transformation rules and define gauge invariance. The formalism is completely general and can be used in different applications of general relativity or any other spacetime theory

Replication origins oriGNAI3 and oriB of the mammalian AMPD2 locus nested in a region of straight DNA flanked by intrinsically bent DNA sites.

Science.gov (United States)

Balani, Valério Américo; de Lima Neto, Quirino Alves; Takeda, Karen Izumi; Gimenes, Fabrícia; Fiorini, Adriana; Debatisse, Michelle; Fernandez, Maria Aparecida

2010-11-01

The aim of this work was to determine whether intrinsically bent DNA sites are present at, or close to, the mammalian replication origins oriGNAI3 and oriB in the Chinese hamster AMPD2 locus. Using an electrophoretic mobility shift assay and in silico analysis, we located four intrinsically bent DNA sites (b1 to b4) in a fragment that contains the oriGNAI3 and one site (b5) proximal to oriB. The helical parameters show that each bent DNA site is curved in a left-handed superhelical writhe. A 2D projection of 3D fragment trajectories revealed that oriGNAI3 is located in a relatively straight segment flanked by bent sites b1 and b2, which map in previously identified Scaffold/Matrix Attachment Region. Sites b3 and b4 are located approximately 2 kb downstream and force the fragment into a strong closed loop structure. The b5 site is also located in an S/MAR that is found just downstream of oriB.

Electrostatic potential in a bent piezoelectric nanowire with consideration of size-dependent piezoelectricity and semiconducting characterization.

Science.gov (United States)

Wang, Kaifa; Wang, Baolin

2018-03-26

Determining the electric potential in a bent piezoelectric nanowire (NW) is a fundamental issue of nanogenerators and nanopiezotronics. The combined influence of the flexoelectric effect, the semiconducting performance and the angle of atomic force microscope (AFM) tip has never been studied previously and will be investigated in this paper. The exact solution for the electric potential of a bent piezoelectric semiconductor NW is derived. The electric potential of the present model with consideration of flexoelectric effect varies along the length of the NW and is different from that of the classical piezoelectric model. Flexoelectric effect enhances but the semiconducting performance reduces the electric potential of the NW. In addition, it is found that if the angle of the AFM tip reaches 30 degrees, the error of the electric potential obtained from the model ignored the effect of the angle of the AFM tip is almost 16%, which is unacceptable. © 2018 IOP Publishing Ltd.

BRST gauge fixing and regularization

International Nuclear Information System (INIS)

Damgaard, P.H.; Jonghe, F. de; Sollacher, R.

1995-05-01

In the presence of consistent regulators, the standard procedure of BRST gauge fixing (or moving from one gauge to another) can require non-trivial modifications. These modifications occur at the quantum level, and gauges exist which are only well-defined when quantum mechanical modifications are correctly taken into account. We illustrate how this phenomenon manifests itself in the solvable case of two-dimensional bosonization in the path-integral formalism. As a by-product, we show how to derive smooth bosonization in Batalin-Vilkovisky Lagrangian BRST quantization. (orig.)

Covariant gauges at finite temperature

CERN Document Server

Landshoff, Peter V

1992-01-01

A prescription is presented for real-time finite-temperature perturbation theory in covariant gauges, in which only the two physical degrees of freedom of the gauge-field propagator acquire thermal parts. The propagators for the unphysical degrees of freedom of the gauge field, and for the Faddeev-Popov ghost field, are independent of temperature. This prescription is applied to the calculation of the one-loop gluon self-energy and the two-loop interaction pressure, and is found to be simpler to use than the conventional one.

Observation and comparative analysis of proton beam extraction or collimation by different planar channels of a bent crystal

Directory of Open Access Journals (Sweden)

A. G. Afonin

2012-08-01

Full Text Available In the experiment the efficiency of the 50 GeV proton beam extraction from accelerator by means of a bent crystal as a function of crystal orientation was measured. This allowed one to make a comparative analysis of efficiencies of high-energy protons deflection by different crystal atomic planes with different values of the electrostatic field. The results of simulation of high-energy protons deflection by means of crystal atomic planes and crystal atomic strings are also presented in the article. In the case of planar channeling the simulation shows a good agreement with experimental data. In the case of proton motion in the regime of stochastic scattering by bent atomic strings the simulation shows that angles of particle deflection are much greater than the critical channeling angle.

Recursive relations for a quiver gauge theory

International Nuclear Information System (INIS)

Park, Jaemo; Sim, Woojoo

2006-01-01

We study the recursive relations for a quiver gauge theory with the gauge group SU(N 1 ) x SU(N 2 ) with bifundamental fermions transforming as (N 1 , N-bar 2 ). We work out the recursive relation for the amplitudes involving a pair of quark and antiquark and gluons of each gauge group. We realize directly in the recursive relations the invariance under the order preserving permutations of the gluons of the first and the second gauge group. We check the proposed relations for MHV, 6-point and 7-point amplitudes and find the agreements with the known results and the known relations with the single gauge group amplitudes. The proposed recursive relation is much more efficient in calculating the amplitudes than using the known relations with the amplitudes of the single gauge group

Fast Neutral Pressure Gauges in NSTX

International Nuclear Information System (INIS)

Raman, R.; Kugel, H.W.; Gernhardt, R.; Provost, T.; Jarboe, T.R.; Soukhanovskii, V.

2004-01-01

Successful operation in NSTX of two prototype fast-response micro ionization gauges during plasma operations has motivated us to install five gauges at different toroidal and poloidal locations to measure the edge neutral pressure and its dependence on the type of discharge (L-mode, H-mode, CHI) and the fueling method and location. The edge neutral pressure is also used as an input to the transport analysis codes TRANSP and DEGAS-2. The modified PDX-type Penning gauges are well suited for pressure measurements in the NSTX divertor where the toroidal field is relatively high. Behind the NSTX outer divertor plates where the field is lower, an unshielded fast ion gauge of a new design has been installed. This gauge was developed after laboratory testing of several different designs in a vacuum chamber with applied magnetic fields

Perturbative unitarity constraints on gauge portals

Science.gov (United States)

El Hedri, Sonia; Shepherd, William; Walker, Devin G. E.

2017-12-01

Dark matter that was once in thermal equilibrium with the Standard Model is generally prohibited from obtaining all of its mass from the electroweak phase transition. This implies a new scale of physics and mediator particles to facilitate dark matter annihilation. In this work, we focus on dark matter that annihilates through a generic gauge boson portal. We show how partial wave unitarity places upper bounds on the dark gauge boson, dark Higgs and dark matter masses. Outside of well-defined fine-tuned regions, we find an upper bound of 9 TeV for the dark matter mass when the dark Higgs and dark gauge bosons both facilitate the dark matter annihilations. In this scenario, the upper bound on the dark Higgs and dark gauge boson masses are 10 TeV and 16 TeV, respectively. When only the dark gauge boson facilitates dark matter annihilations, we find an upper bound of 3 TeV and 6 TeV for the dark matter and dark gauge boson, respectively. Overall, using the gauge portal as a template, we describe a method to not only place upper bounds on the dark matter mass but also on the new particles with Standard Model quantum numbers. We briefly discuss the reach of future accelerator, direct and indirect detection experiments for this class of models.

Gaugings at angles from orientifold reductions

International Nuclear Information System (INIS)

Roest, Diederik

2009-01-01

We consider orientifold reductions to N= 4 gauged supergravity in four dimensions. A special feature of this theory is that different factors of the gauge group can have relative angles with respect to the electro-magnetic SL(2) symmetry. These are crucial for moduli stabilization and de Sitter vacua. We show how such gaugings at angles generically arise in orientifold reductions.

Viscous conformal gauge theories

DEFF Research Database (Denmark)

Toniato, Arianna; Sannino, Francesco; Rischke, Dirk H.

2017-01-01

We present the conformal behavior of the shear viscosity-to-entropy density ratio and the fermion-number diffusion coefficient within the perturbative regime of the conformal window for gauge-fermion theories.......We present the conformal behavior of the shear viscosity-to-entropy density ratio and the fermion-number diffusion coefficient within the perturbative regime of the conformal window for gauge-fermion theories....

Nonabelian generalized gauge multiplets

International Nuclear Information System (INIS)

Lindstroem, Ulf; Zabzine, Maxim; Rocek, Martin; Ryb, Itai; Unge, Rikard von

2009-01-01

We give the nonabelian extension of the newly discovered N = (2, 2) two-dimensional vector multiplets. These can be used to gauge symmetries of sigma models on generalized Kaehler geometries. Starting from the transformation rule for the nonabelian case we find covariant derivatives and gauge covariant field-strengths and write their actions in N = (2, 2) and N = (1, 1) superspace.

RIKEN BNL RESEARCH CENTER WORKSHOP ON GAUGE-INVARIANT VARIABLES IN GAUGE THEORIES, VOLUME 20

Energy Technology Data Exchange (ETDEWEB)

VAN BAAL,P.; ORLAND,P.; PISARSKI,R.

2000-06-01

This four-day workshop focused on the wide variety of approaches to the non-perturbative physics of QCD. The main topic was the formulation of non-Abelian gauge theory in orbit space, but some other ideas were discussed, in particular the possible extension of the Maldacena conjecture to nonsupersymmetric gauge theories. The idea was to involve most of the participants in general discussions on the problem. Panel discussions were organized to further encourage debate and understanding. Most of the talks roughly fell into three categories: (1) Variational methods in field theory; (2) Anti-de Sitter space ideas; (3) The fundamental domain, gauge fixing, Gribov copies and topological objects (both in the continuum and on a lattice). In particular some remarkable progress in three-dimensional gauge theories was presented, from the analytic side by V.P. Nair and mostly from the numerical side by O. Philipsen. This work may ultimately have important implications for RHIC experiments on the high-temperature quark-gluon plasma.

Generally covariant gauge theories

International Nuclear Information System (INIS)

Capovilla, R.

1992-01-01

A new class of generally covariant gauge theories in four space-time dimensions is investigated. The field variables are taken to be a Lie algebra valued connection 1-form and a scalar density. Modulo an important degeneracy, complex [euclidean] vacuum general relativity corresponds to a special case in this class. A canonical analysis of the generally covariant gauge theories with the same gauge group as general relativity shows that they describe two degrees of freedom per space point, qualifying therefore as a new set of neighbors of general relativity. The modification of the algebra of the constraints with respect to the general relativity case is computed; this is used in addressing the question of how general relativity stands out from its neighbors. (orig.)

General treatment of a non-linear gauge condition

International Nuclear Information System (INIS)

Malleville, C.

1982-06-01

A non linear gauge condition is presented in the frame of a non abelian gauge theory broken with the Higgs mechanism. It is shown that this condition already introduced for the standard SU(2) x U(1) model can be generalized for any gauge model with the same type of simplification, namely the suppression of any coupling of the form: massless gauge boson, massive gauge boson, unphysical Higgs [fr

Gauge field entanglement in Kitaev's honeycomb model

Science.gov (United States)

Dóra, Balázs; Moessner, Roderich

2018-01-01

A spin fractionalizes into matter and gauge fermions in Kitaev's spin liquid on the honeycomb lattice. This follows from a Jordan-Wigner mapping to fermions, allowing for the construction of a minimal entropy ground-state wave function on the cylinder. We use this to calculate the entanglement entropy by choosing several distinct partitionings. First, by partitioning an infinite cylinder into two, the -ln2 topological entanglement entropy is reconfirmed. Second, the reduced density matrix of the gauge sector on the full cylinder is obtained after tracing out the matter degrees of freedom. This allows for evaluating the gauge entanglement Hamiltonian, which contains infinitely long-range correlations along the symmetry axis of the cylinder. The matter-gauge entanglement entropy is (Ny-1 )ln2 , with Ny the circumference of the cylinder. Third, the rules for calculating the gauge sector entanglement of any partition are determined. Rather small correctly chosen gauge partitions can still account for the topological entanglement entropy in spite of long-range correlations in the gauge entanglement Hamiltonian.

Gauge invariance and degree of freedom count

International Nuclear Information System (INIS)

Henneaux, M.; Universite Libre de Bruxelles; Teitelboim, C.; Texas Univ., Austin; Zanelli, J.; Chile Univ., Santiago. Dept. de Fisica)

1990-01-01

The precise relation between the gauge transformations in lagrangian and hamiltonian form is derived for any gauge theory. It is found that in order to define a lagrangian gauge symmetry, the coefficients of the first class constraints in the hamiltonian generator of gauge transformations must obey a set of differential equations. Those equations involve, in general, the Lagrange multipliers. Their solution contains as many arbitrary functions of time as there are primary first class constraints. If n is the number of generations of constraints (primary, secondary, tertiary...), the arbitrary functions appear in the general solution together with their successive time derivatives up to order n-1. The analysis yields as by-products: (i) a systematic way to derive all the gauge symmetries of a given lagrangian; (ii) a precise criterion for counting the physical degrees of freedom of a gauge theory directly from the form of gauge transformations in lagrangian form. This last part is illustrated by means of examples. The BRST analog of the counting of physical degrees of freedom is also discussed. (orig.)

Non-Abelian gauge fields in two spatial dimensions

International Nuclear Information System (INIS)

Hagen, C.R.

1987-01-01

Generalizing an earlier work on the Abelian case the most general non-Abelian gauge theory in two spatial dimensions is derived. It is shown that local gauge invariance leads to a new term in the action which in turn requires that the gauge current operator have a part which is bilinear in the non-Abelian gauge field-strength tensor. Although a radiation (or axial) gauge quantization is possible, this approach is found not to yield the maximal set of commutation relations among the basic fields. The latter goal can be accomplished only by a rather unusual gauge choice which has not previously been studied. Quantization conditions on the coupling constant implied by invariance under large gauge transformations are also derived

Pressure gauge experiments in India

Digital Repository Service at National Institute of Oceanography (India)

Joseph, A; Desa, E.; VijayKumar, K.; Desa, E.S.; Desai, R.G.P.; Prabhudesai, S.

. The effective mean density directly estimated by the use of a dual pressure gauge system was in close agreement with the density of water samples measured using a precision densitometer. Good quality sea level measurements can be obtained from pressure gauges...

Gauging hidden symmetries in two dimensions

International Nuclear Information System (INIS)

Samtleben, Henning; Weidner, Martin

2007-01-01

We initiate the systematic construction of gauged matter-coupled supergravity theories in two dimensions. Subgroups of the affine global symmetry group of toroidally compactified supergravity can be gauged by coupling vector fields with minimal couplings and a particular topological term. The gauge groups typically include hidden symmetries that are not among the target-space isometries of the ungauged theory. The gaugings constructed in this paper are described group-theoretically in terms of a constant embedding tensor subject to a number of constraints which parametrizes the different theories and entirely encodes the gauged Lagrangian. The prime example is the bosonic sector of the maximally supersymmetric theory whose ungauged version admits an affine e 9 global symmetry algebra. The various parameters (related to higher-dimensional p-form fluxes, geometric and non-geometric fluxes, etc.) which characterize the possible gaugings, combine into an embedding tensor transforming in the basic representation of e 9 . This yields an infinite-dimensional class of maximally supersymmetric theories in two dimensions. We work out and discuss several examples of higher-dimensional origin which can be systematically analyzed using the different gradings of e 9

Gauge-Higgs unification in higher dimensions

International Nuclear Information System (INIS)

Hall, Lawrence; Nomura, Yasunori; Smith, David

2002-01-01

The electroweak Higgs doublets are identified as components of a vector multiplet in a higher-dimensional supersymmetric field theory. We construct a minimal model in 6D where the electroweak SU(2)xU(1) gauge group is extended to SU(3), and unified 6D models with the unified SU(5) gauge symmetry extended to SU(6). In these realistic theories the extended gauge group is broken by orbifold boundary conditions, leaving Higgs doublet zero modes which have Yukawa couplings to quarks and leptons on the orbifold fixed points. In one SU(6) model the weak mixing angle receives power law corrections, while in another the fixed point structure forbids such corrections. A 5D model is also constructed in which the Higgs doublet contains the fifth component of the gauge field. In this case Yukawa couplings are introduced as nonlocal operators involving the Wilson line of this gauge field

Weyl gravity as a gauge theory

Science.gov (United States)

Trujillo, Juan Teancum

In 1920, Rudolf Bach proposed an action based on the square of the Weyl tensor or CabcdCabcd where the Weyl tensor is an invariant under a scaling of the metric. A variation of the metric leads to the field equation known as the Bach equation. In this dissertation, the same action is analyzed, but as a conformal gauge theory. It is shown that this action is a result of a particular gauging of this group. By treating it as a gauge theory, it is natural to vary all of the gauge fields independently, rather than performing the usual fourth-order metric variation only. We show that solutions of the resulting vacuum field equations are all solutions to the vacuum Einstein equation, up to a conformal factor---a result consistent with local scale freedom. We also show how solutions for the gauge fields imply there is no gravitational self energy.

An infinite-dimensional calculus for gauge theories

OpenAIRE

Mendes, Rui Vilela

2010-01-01

A space for gauge theories is defined, using projective limits as subsets of Cartesian products of homomorphisms from a lattice on the structure group. In this space, non-interacting and interacting measures are defined as well as functions and operators. From projective limits of test functions and distributions on products of compact groups, a projective gauge triplet is obtained, which provides a framework for the infinite-dimensional calculus in gauge theories. The gauge measure behavior ...

Analytic stochastic regularization: gauge and supersymmetry theories

International Nuclear Information System (INIS)

Abdalla, M.C.B.

1988-01-01

Analytic stochastic regularization for gauge and supersymmetric theories is considered. Gauge invariance in spinor and scalar QCD is verified to brak fown by an explicit one loop computation of the two, theree and four point vertex function of the gluon field. As a result, non gauge invariant counterterms must be added. However, in the supersymmetric multiplets there is a cancellation rendering the counterterms gauge invariant. The calculation is considered at one loop order. (author) [pt

V A Fock and gauge symmetry

International Nuclear Information System (INIS)

Okun, Lev B

2010-01-01

V A Fock, in 1926, was the first to have the idea of an Abelian gradient transformation and to discover that the electromagnetic interaction of charged particles has a gradient invariance in the framework of quantum mechanics. These transformation and invariance were respectively named Eichtransformation and Eichinvarianz by H Weyl in 1929 (the German verb zu eichen means to gauge). The first non-Abelian gauge theory was suggested by O Klein in 1938; and in 1954, C N Yang and R L Mills rediscovered the non-Abelian gauge symmetry. Gauge invariance is the underlying principle of the current Standard Model of strong and electroweak interactions. (from the history of physics)

Measuring systolic ankle and toe pressure using the strain gauge technique--a comparison study between mercury and indium-gallium strain gauges

DEFF Research Database (Denmark)

Broholm, Rikke; Wiinberg, Niels; Simonsen, Lene

2014-01-01

BACKGROUND: Measurement of the ankle and toe pressures are often performed using a plethysmograph, compression cuffs and a strain gauge. Usually, the strain gauge contains mercury but other alternatives exist. From 2014, the mercury-containing strain gauge will no longer be available in the Europ......BACKGROUND: Measurement of the ankle and toe pressures are often performed using a plethysmograph, compression cuffs and a strain gauge. Usually, the strain gauge contains mercury but other alternatives exist. From 2014, the mercury-containing strain gauge will no longer be available...... in the European Union. The aim of this study was to compare an indium-gallium strain gauge to the established mercury-containing strain gauge. METHODS: Consecutive patients referred to the Department of Clinical Physiology and Nuclear Medicine at Bispebjerg and Frederiksberg Hospitals for measurements of systolic...... ankle and toe pressures volunteered for the study. Ankle and toe pressures were measured twice with the mercury and the indium-gallium strain gauge in random order. Comparison of the correlation between the mean pressure using the mercury and the indium-gallium device and the difference between the two...

Color superconductivity, ZN flux tubes and monopole confinement in deformed N=2* super Yang-Mills theories

International Nuclear Information System (INIS)

Kneipp, Marco A.C.

2003-11-01

We study the ZN flux tubes and monopole confinement in deformed N=2* super Yang-Mills theories. In order to do that we consider an N=4 super Yang-Mills theory with an arbitrary gauge group G and add some N=2, N=1 and N=0 deformation terms. We analyze some possible vacuum solutions and phases of the theory, depending on the deformation terms which are added. In the Coulomb phase for the N=2* theory, G is broken to U(1)r and the theory has monopole solutions. Then, by adding some deformation terms, the theory passes to the Higgs or color superconducting phase, in which G is broken to its center CG. In this phase we construct the ZN flux tubes Ansatz and obtain the BPS string tension. We show that the monopole magnetic fluxes are linear integer combinations of the string fluxes and therefore the monopoles can become confined. Then, we obtain a bound for the threshold length of the string-breaking. We also show the possible formation of a confining system with 3 different monopoles for the SU(3) gauge group. Finally we show that the BPS string tensions of the theory satisfy the Casimir scaling law. (author)

A study of the effect of maintenance on the safety of a mechanical system subject to aging and its application to steam generator tube degradation

International Nuclear Information System (INIS)

Dussarte, D.

1991-11-01

The different degradation mechanisms to which pressurized water reactor steam generator tubes are observed to be subject may result in the risk of their rupture being greater than anticipated. Prevention of tube rupture essentially consists of inspections during outages of the units and applying appropriate criteria for the withdrawal of defective tubes from service. Planning such measures implies being able to gauge the effectiveness of the action taken. This document describes a proposed technique for quantifying the effects of the preventive maintenance we have had to develop to address this problem and, hence, to obtain material for assessing the action taken by the utility. (author)

Absence of the Gribov ambiguity in a quadratic gauge

International Nuclear Information System (INIS)

Raval, Haresh

2016-01-01

The Gribov ambiguity exists in various gauges. Algebraic gauges are likely to be ambiguity free. However, algebraic gauges are not Lorentz invariant, which is their fundamental flaw. In addition, they are not generally compatible with the boundary conditions on the gauge fields, which are needed to compactify the space i.e., the ambiguity continues to exist on a compact manifold. Here we discuss a quadratic gauge fixing, which is Lorentz invariant. We consider an example of a spherically symmetric gauge field configuration in which we prove that this Lorentz invariant gauge removes the ambiguity on a compact manifold S 3 , when a proper boundary condition on the gauge configuration is taken into account. Thus, we provide one example where the ambiguity is absent on a compact manifold in the algebraic gauge. We also show that the BRST invariance is preserved in this gauge. (orig.)

Absence of the Gribov ambiguity in a quadratic gauge

Energy Technology Data Exchange (ETDEWEB)

Raval, Haresh [Indian Institute of Technology, Bombay, Department of Physics, Mumbai (India)

2016-05-15

The Gribov ambiguity exists in various gauges. Algebraic gauges are likely to be ambiguity free. However, algebraic gauges are not Lorentz invariant, which is their fundamental flaw. In addition, they are not generally compatible with the boundary conditions on the gauge fields, which are needed to compactify the space i.e., the ambiguity continues to exist on a compact manifold. Here we discuss a quadratic gauge fixing, which is Lorentz invariant. We consider an example of a spherically symmetric gauge field configuration in which we prove that this Lorentz invariant gauge removes the ambiguity on a compact manifold S{sup 3}, when a proper boundary condition on the gauge configuration is taken into account. Thus, we provide one example where the ambiguity is absent on a compact manifold in the algebraic gauge. We also show that the BRST invariance is preserved in this gauge. (orig.)

A simple criterion for determining the static friction force between nanowires and flat substrates using the most-bent-state method.

Science.gov (United States)

Hou, Lizhen; Wang, Shiliang; Huang, Han

2015-04-24

A simple criterion was developed to assess the appropriateness of the currently available models that estimate the static friction force between nanowires and substrates using the 'most-bent-state' method. Our experimental testing of the static friction force between Al2O3 nanowires and Si substrate verified our theoretical analysis, as well as the establishment of the criterion. It was found that the models are valid only for the bent nanowires with the ratio of wire length over the minimum curvature radius [Formula: see text] no greater than 1. For the cases with [Formula: see text] greater than 1, the static friction force was overestimated as it neglected the effect of its tangential component.

SU(N) chiral gauge theories on the lattice

International Nuclear Information System (INIS)

Golterman, Maarten; Shamir, Yigal

2004-01-01

We extend the construction of lattice chiral gauge theories based on non-perturbative gauge fixing to the non-Abelian case. A key ingredient is that fermion doublers can be avoided at a novel type of critical point which is only accessible through gauge fixing, as we have shown before in the Abelian case. The new ingredient allowing us to deal with the non-Abelian case as well is the use of equivariant gauge fixing, which handles Gribov copies correctly, and avoids Neuberger's no-go theorem. We use this method in order to gauge fix the non-Abelian group (which we will take to be SU(N)) down to its maximal Abelian subgroup. Obtaining an undoubled, chiral fermion content requires us to gauge-fix also the remaining Abelian gauge symmetry. This modifies the equivariant Becchi-Rouet-Stora-Tyutin (BRST) identities, but their use in proving unitarity remains intact, as we show in perturbation theory. On the lattice, equivariant BRST symmetry as well as the Abelian gauge invariance are broken, and a judiciously chosen irrelevant term must be added to the lattice gauge-fixing action in order to have access to the desired critical point in the phase diagram. We argue that gauge invariance is restored in the continuum limit by adjusting a finite number of counter terms. We emphasize that weak-coupling perturbation theory applies at the critical point which defines the continuum limit of our lattice chiral gauge theory

Amorphous gauge glass theory

International Nuclear Information System (INIS)

Nielsen, H.B.; Bennett, D.L.

1987-08-01

Assuming that a lattice gauge theory describes a fundamental attribute of Nature, it should be pointed out that such a theory in the form of a gauge glass is a weaker assumption than a regular lattice model in as much as it is not constrained by the imposition of translational invariance; translational invariance is, however, recovered approximately in the long wavelength or continuum limit. (orig./WL)

The gauge hierarchy problem

International Nuclear Information System (INIS)

Natale, A.A.; Shellard, R.C.

1981-01-01

The problem of gauge hierarchy in Grand Unified Theories using a toy model with O(N) symmetry is discussed. It is shown that there is no escape to the unnatural adjustment of coupling constants, made only after the computation of several orders in perturbation theory is performed. The propositions of some authors on ways to overcome the gauge hierarchy problem are commented. (Author) [pt

Technical data on nucleonic gauges

International Nuclear Information System (INIS)

2005-07-01

This nucleonic gauge manual and directory provides a reference database of nucleonic control systems available to potential users in the fields of exploration, exploitation and processing of natural resources and in the manufacturing industries. It starts with background information an the general principals of nucleonic gauges, followed by portable nuclear analysis systems (PNAS), computer tomography, cost-benefit on NCS (Nucleonic Control Systems) applications and trends and transfer of NCS technology. It continues with radiation protection and safety, discusses nucleonic gauges with low radioactivity sources and ends with typical models of nucleonic gauges. The basic principles of the most popular techniques are reviewed and reference data links to suppliers are provided. Information sheets on many typical commercial devices are also included. It will help end-users to select the most suitable alternative to solve a particular problem or to measure a certain parameter in a specific process

Gauge theories in particle physics

International Nuclear Information System (INIS)

Aitchison, I.J.R.; Hey, A.J.G.

1982-01-01

The first theory, quantum electrodynamics (QED) is known to give a successful account of electromagnetic interactions. Weak and strong interactions are described by gauge theories which are generalisations of QED. The electro-weak gauge theory of Glashow Salam and Weinberg unites electromagnetic and weak interactions. Quantum chromodynamics (QCD) is the gauge theory of strong interactions. This approach to these theories, designed for the non-specialist, is based on a straightforward generalisation of non-relativistic quantum-mechanical perturbation theory to the relativistic case, leading to an intuitive introduction to Feynman graphs. Spontaneously broken-or 'hidden'-symmetries are given particular attention, with the physics of hidden gauge invariance and the role of the vacuum (essential to the unified theories) being illustrated by an extended but elementary discussion of the non-relativistic example of superconductivity. Throughout, emphasis is placed both on realistic calculations and on physical understanding. (author)

Symmetry gauge theory for paraparticles

International Nuclear Information System (INIS)

Kursawe, U.

1986-01-01

In the present thesis it was shown that for identical particles the wave function of which has a more complicated symmetry than it is the case at the known kinds of particles, the bosons and fermions, a gauge theory can be formulated, the so-called 'symmetry gauge theory'. This theory has its origin alone in the symmetry of the particle wave functions and becomes first relevant when more than two particles are considered. It was shown that for particles with mixed-symmetrical wave functions, so-called 'paraparticles', the quantum mechanical state is no more described by one Hilbert-space element but by a many-dimensional subspace of this Hilbert space. The gauge freedom consists then just in the freedom of the choice of the basis in this subspace, the corresponding gauge group is the group of the unitary basis transformation in this subspace. (orig./HSI) [de

An experimental study on anti-electrostatic gauge rulers

International Nuclear Information System (INIS)

Lou, Renjie; Dai, Liping; Sun, Hong

2013-01-01

The process of oil filling will produce electrostatic phenomena which may cause fire accidents. There were no reports about research on the danger of static electricity generation in the process of gauging operation to date. This paper presents an experiment on charge transferring quantity of gauge rulers, and calculates the charge transferring quantity of an anti-electrostatic gauge ruler and a metal one, respectively. The results indicate that the charge transferring quantity can be more than 0.1 μC for a metal gauge ruler, while it is less than 0.1 μC for an antistatic gauge ruler. Therefore, this experimental research proves that using an anti-electrostatic gauge ruler is safer than using a metal one. This study also provides some theoretical and experimental evidence for making anti-electrostatic gauge rulers.

Noncommutative induced gauge theories on Moyal spaces

International Nuclear Information System (INIS)

Wallet, J-C

2008-01-01

Noncommutative field theories on Moyal spaces can be conveniently handled within a framework of noncommutative geometry. Several renormalisable matter field theories that are now identified are briefly reviewed. The construction of renormalisable gauge theories on these noncommutative Moyal spaces, which remains so far a challenging problem, is then closely examined. The computation in 4-D of the one-loop effective gauge theory generated from the integration over a scalar field appearing in a renormalisable theory minimally coupled to an external gauge potential is presented. The gauge invariant effective action is found to involve, beyond the expected noncommutative version of the pure Yang-Mills action, additional terms that may be interpreted as the gauge theory counterpart of the harmonic term, which for the noncommutative ψ 4 -theory on Moyal space ensures renormalisability. A class of possible candidates for renormalisable gauge theory actions defined on Moyal space is presented and discussed

Discretisation errors in Landau gauge on the lattice

International Nuclear Information System (INIS)

Bonnet DR, Frederic; Bowman O, Patrick; Leinweber B, Derek; Williams G, Anthony; Richards G, David G.

1999-01-01

Lattice discretization errors in the Landau gauge condition are examined. An improved gauge fixing algorithm in which O(a 2 ) errors are removed is presented. O(a 2 ) improvement of the gauge fixing condition improves comparison with continuum Landau gauge in two ways: (1) through the elimination of O(a 2 ) errors and (2) through a secondary effect of reducing the size of higher-order errors. These results emphasize the importance of implementing an improved gauge fixing condition

Some new applications of nucleonic gauges in Russia

International Nuclear Information System (INIS)

Fedorkov, V.G.

2000-01-01

Russia has been a big producer of nucleonic gauges for many years. There are still some institutions that design and manufacture nucleonic gauges for industry, like level gauges, density gauges and thickness gauges. Industrial demands for NCS (especially after the Chernobyl accident) have been decreasing. Examples of recent development are given in this paper. Substantial improvements in the hardware, source and detectors system, are being undertaken. The potential for new applications is large, also, there is a good capability of local researchers for increasing the quality and quantity of nucleonic gauges in industry to meet local needs and to compete better in the international scale and market. (author)

Quartz gauge response in ion radiation

International Nuclear Information System (INIS)

Taylor, P.E.; Gilbert, P.H.; Kernthaler, C.; Anderson, M.U.

1995-01-01

This paper describes recent work to make high quality quartz gauge (temporal and spatial) shock wave measurements in a pulsed ion beam environment. Intense ion beam radiation, nominally 1 MeV protons, was deposited into material samples instrumented with shunted quartz gauges adjacent to the ion deposition zone. Fluence levels were chosen to excite three fundamentally different material response modes (1) strong vapor, (2) combined vapor and melt phase and (3) thermoelastic material response. A unique quartz gauge design was utilized that employed printed circuit board (PCB) technology to facilitate electrical shielding, ruggedness, and fabrication at sign e meeting the essential one dimensional requirements of the characterized Sandia shunted quartz gauge. Shock loading and unloading experiments were conducted to evaluate the piezoelectric response of the coupled quartz gauge/PCB transducer. High fidelity shock wave profiles were recorded at the three ion fluence levels providing dynamic material response data for vapor, melt and solid material phases

Can (electric-magnetic) duality be gauged?

International Nuclear Information System (INIS)

Bunster, Claudio; Henneaux, Marc

2011-01-01

There exists a formulation of the Maxwell theory in terms of two vector potentials, one electric and one magnetic. The action is then manifestly invariant under electric-magnetic duality transformations, which are rotations in the two-dimensional internal space of the two potentials, and local. We ask the question: Can duality be gauged? The only known and battle-tested method of accomplishing the gauging is the Noether procedure. In its decanted form, it amounts to turning on the coupling by deforming the Abelian gauge group of the free theory, out of whose curvatures the action is built, into a non-Abelian group which becomes the gauge group of the resulting theory. In this article, we show that the method cannot be successfully implemented for electric-magnetic duality. We thus conclude that, unless a radically new idea is introduced, electric-magnetic duality cannot be gauged. The implication of this result for supergravity is briefly discussed.

Fried-Yennie gauge in dimensionally regularized QED

International Nuclear Information System (INIS)

Adkins, G.S.

1993-01-01

The Fried-Yennie gauge in QED is a covariant gauge with agreeable infrared properties. That is, the mass-shell renormalization scheme can be implemented without introducing artificial infrared divergences, and terms having spuriously low orders in α disappear in certain bound-state calculations. The photon propagator in the Fried-Yennie gauge has the form D β μν (k)=(-1/k 2 )[g μν +βk μ kν/k 2 ], where β is the gauge parameter. In this work, I show that the Fried-Yennie gauge parameter is β=2/(1-2ε) when dimensional regularization (with n=4-2ε dimensions of spacetime) is used to regulate the theory

Experimental evidence for multi-pass extraction with a bent crystal

CERN Document Server

Dehning, Bernd; Fidecaro, Giuseppe; Gyr, Marcel; Herr, Werner; Klem, J T; Scandale, Walter; Vuagnin, G; Weisse, E; Weisz, S; Møller, S P; Uggerhøj, Erik; Freund, A; Hustache, R; Carboni, G; Bussa, M P; Tosello, F

1996-01-01

The feasibility of extracting particles from the halo of a circulating proton beam using a bent silicon crystal has been demonstrated experimentally at the SPS for a beam energy of 120 GeV. Presently studies are conducted to understand the extraction mechanisms and the measured efficiencies. In particular the contribution of multi-pass extraction, where the particles can pass through the crystal many times before being channelled and extracted, is investigated. In a recent experiment, using a crystal especially fabricated with a finite amorphous layer on its surface, it has been proven that multi-pass extraction plays an important role. The experiment is described and the implication for further studies are discussed.

Gravitating SO (3,1) gauge field

International Nuclear Information System (INIS)

Aragone, C.; Restuccia, A.

1978-01-01

In this article, we postulate SO (3,1) as a local symmetry of any relativistic theory. This is equivalent to assuming the existence of a gauge field associated with this noncompact group. This SO (3,1) gauge field is the spinorial affinity which usually appears when we deal with weighting spinors, which, as is well known, cannot be coupled to the metric tensor field. Furthermore, according to the integral approach to gauge fields proposed by Yang, it is also recognized that in order to obtain models of gravity we have to introduce ordinary affinities as the gauge field associated with GL (4) (the local symmetry determined by the parallel transport). Thus if we assume both GL (4) and SO (3,1) as local independent symmetries we are led to analyze the dynamical gauge system constituted by the Einstein field interacting with the SO (3,1) Weyl--Yang gauge field. We think this system is a possible model of strong gravity. Once we give the first-order action for this Einstein--Weyl--Yang system we study whether the SO (3,1) gauge field could have a tetrad associated with it. It is also shown that both fields propagate along a unique characteristic cone. Algebraic and differential constraints are solved when the system evolves along a null coordinate. The unconstrained expression for the action of the system is found working in the Bondi gauge. That allows us to exhibit an explicit expression of the dynamical generator of the system. Its signature turns out to be nondefinite, due to the nondefinite contribution of the Weyl--Yang field, which has the typical spinorial behavior. A conjecture is made that such an unpleasant feature could be overcome in the quantized version of this model

Expanding the Bethe/Gauge dictionary

Science.gov (United States)

Bullimore, Mathew; Kim, Hee-Cheol; Lukowski, Tomasz

2017-11-01

We expand the Bethe/Gauge dictionary between the XXX Heisenberg spin chain and 2d N = (2, 2) supersymmetric gauge theories to include aspects of the algebraic Bethe ansatz. We construct the wave functions of off-shell Bethe states as orbifold defects in the A-twisted supersymmetric gauge theory and study their correlation functions. We also present an alternative description of off-shell Bethe states as boundary conditions in an effective N = 4 supersymmetric quantum mechanics. Finally, we interpret spin chain R-matrices as correlation functions of Janus interfaces for mass parameters in the supersymmetric quantum mechanics.

Gauge theory of amorphous magnets

International Nuclear Information System (INIS)

Nesterov, A.I.; Ovchinnikov, S.G.

1989-01-01

A gauge theory of disordered magnets as a field theory in the principal fiber bundle with structure group SL(3, R) is constructed. The gauge field interacting with a vector field (the magnetization) is responsible for the disorder. A complete system of equations, valid for arbitrary disordered magnets, is obtained. In the limiting case of a free gauge field the proposed approach leads to the well-known Volovik-Dzyaloshinskii theory, which describes isotropic spin glasses. In the other limiting case when the curvature is zero the results of Ignatchenko and Iskhakov for weakly disordered ferromagnets are reproduced

'Baldin autumn' and gauge fields

International Nuclear Information System (INIS)

Konopleva, N.P.

2008-01-01

The paper is the reminiscences of the participant of the gauge field theory beginning and the first 'Baldin Autumn' conference in 1969. This conference was named 'Vector Mesons and Electromagnetic Interactions'. At that time, just the processes with vector mesons participation contained some experimental indications of new universal interactions existence. Vector dominance was the experimental evidence of physical reasons of the gauge field theory. In the course of time the gauge field theory form, which was under discussion thirty seven years ago, became generally recognized and experimentally corroborated. It led to construction of the well-known Standard Model of elementary particle interactions

The gauge technique in supersymmetric QED2

NARCIS (Netherlands)

Roo, M. de; Steringa, J.J.

1988-01-01

We construct an extension of the gauge technique to two-dimensional supersymmetric gauge theories. This involves a derivation of the spectral representation of a scalar superpropagator in two dimensions. We apply the method to the massive supersymmetric Schwinger model. In the case that the gauge

Electronic design of air dust concentration gauge

International Nuclear Information System (INIS)

Machaj, B.; Strzalkowski, J.; Krawczynska, B.

1993-01-01

A new version of isotope dust concentration gauge for monitoring airborne dust pollution of air employs a ready made personal computer as the control and processing unit in the gauge instead of specialized electronics. That solution of the gauge reduces the needed specialized electronics to a simple computer interface coupling the computer to the measuring head. This also reduced electronics of the measuring head itself, i.e. GM detector circuit, power supplies and electronic circuits to switch on/off driving motors. The functioning and operation of the gauge is controlled by the computer program that can be easily modified if needed. The computer program for the gauge enables automatic measurements of dust concentration. Up to fifty measuring cycles can be easily programmed for a day. The results of measurements are presented in the form of data collection, diagram of dust concentration distribution during one day, diagram of dust distribution during 30 successive days or diagram of average dust concentration distribution during a day which may be computed by combining data of the selected number of measurements. Recalibration of the gauge and checking up of the gauge are also carried out under the program control. (author). 6 refs, 9 figs

Theorems for asymptotic safety of gauge theories

Energy Technology Data Exchange (ETDEWEB)

Bond, Andrew D.; Litim, Daniel F. [University of Sussex, Department of Physics and Astronomy, Brighton (United Kingdom)

2017-06-15

We classify the weakly interacting fixed points of general gauge theories coupled to matter and explain how the competition between gauge and matter fluctuations gives rise to a rich spectrum of high- and low-energy fixed points. The pivotal role played by Yukawa couplings is emphasised. Necessary and sufficient conditions for asymptotic safety of gauge theories are also derived, in conjunction with strict no go theorems. Implications for phase diagrams of gauge theories and physics beyond the Standard Model are indicated. (orig.)

Discretisation errors in Landau gauge on the lattice

International Nuclear Information System (INIS)

Bonnet, F.D.R.; Bowmen, P.O.; Leinweber, D.B.

1999-01-01

Lattice discretisation errors in the Landau gauge condition are examined. An improved gauge fixing algorithm in which O(a 2 ) errors are removed is presented. O(a 2 ) improvement of the gauge fixing condition improves comparison with the continuum Landau gauge in two ways: (1) through the elimination of O(a 2 ) errors and (2) through a secondary effect of reducing the size of higher-order errors. These results emphasise the importance of implementing an improved gauge fixing condition. Copyright (1999) CSIRO Australia

Sonographically guided core biopsy of the breast: comparison of 14-gauge automated gun and 11-gauge directional vacuum-assisted biopsy methods

International Nuclear Information System (INIS)

Cho, Nariya; Moon, Woo Kyung; Cha, Joo Hee

2005-01-01

To compare the outcomes of 14-gauge automated biopsy and 11-gauge vacuum-assisted biopsy for the sonographically guided core biopsies of breast lesions. We retrospectively reviewed all sonographically guided core biopsies performed from January 2002 to February 2004. The sonographically guided core biopsies were performed with using a 14-gauge automated gun on 562 breast lesions or with using an 11-gauge vacuum-assisted device on 417 lesions. The histologic findings were compared with the surgical, imaging and follow-up findings. The histologic underestimation rate, the repeat biopsy rate and the false negative rates were compared between the two groups. A repeat biopsy was performed on 49 benign lesions because of the core biopsy results of the high-risk lesions (n=24), the imaging-histologic discordance (n=5), and the imaging findings showing disease progression (n=20). The total underestimation rates, according to the biopsy device, were 55% (12/22) for the 14-gauge automated gun biopsies and 36% (8/22) for the 11-gauge vacuum-assisted device (ρ = 0.226). The atypical ductal hyperplasia (ADH) underestimation (i.e., atypical ductal hyperplasia at core biopsy and carcinoma at surgery) was 58% (7/12) for the 14-gauge automated gun biopsies and 20% (1/5) for the 11-gauge vacuum-assisted biopsies. The ductal carcinoma in situ (DCIS) underestimation rate (i.e., ductal carcinoma in situ upon core biopsy and invasive carcinoma found at surgery) was 50% (5/10) for the 14-gauge automated gun biopsies and 41% (7/17) for the 11-gauge vacuum-assisted biopsies. The repeat biopsy rates were 6% (33/562) for the 14-gauge automated gun biopsies and 3.5% (16/417) for the 11-gauge vacuum-assisted biopsies. Only 5 (0.5%) of the 979 core biopsies were believed to have missed the malignant lesions. The false-negative rate was 3% (4 of 128 cancers) for the 14-gauge automated gun biopsies and 1% (1 of 69 cancers) for the 11-gauge vacuum-assisted biopsies. The outcomes of the

Physics from multidimensional gauge theories

International Nuclear Information System (INIS)

Forgacs, P.; Lust, D.; Zoupanos, G.

1986-01-01

The authors motivate high dimensional theories by recalling the original Kaluza-Klein proposal. They review the dimensional reduction of symmetric gauge theories and they present the results of the attempts to obtain realistic description of elementary particles interactions starting from symmetric gauge theories in high dimensions

Gauging away a big bang

Science.gov (United States)

Krishnan, Chethan; Raju, Avinash

2017-08-01

We argue that in the tensionless phase of string theory where the stringy gauge symmetries are unbroken, (at least some) cosmological singularities can be understood as gauge artefacts. We present two conceptually related, but distinct, pieces of evidence: one relying on spacetime and the other on worldsheet.

arXiv Electromagnetic dipole moments of charged baryons with bent crystals at the LHC

CERN Document Server

Bagli, E.; Cavoto, G.; Guidi, V.; Henry, L.; Marangotto, D.; Martinez Vidal, F.; Mazzolari, A.; Merli, A.; Neri, N.; Ruiz Vidal, J.

2017-12-05

We propose a unique program of measurements of electric and magnetic dipole moments of charm, beauty and strange charged baryons at the LHC, based on the phenomenon of spin precession of channeled particles in bent crystals. Studies of crystal channeling and spin precession of positively- and negatively-charged particles are presented, along with feasibility studies and expected sensitivities for the proposed experiment using a layout based on the LHCb detector.

Gauge symmetries, topology, and quantisation

International Nuclear Information System (INIS)

Balachandran, A.P.

1994-01-01

The following two loosely connected sets of topics are reviewed in these lecture notes: (1) Gauge invariance, its treatment in field theories and its implications for internal symmetries and edge states such as those in the quantum Hall effect. (2) Quantisation on multiply connected spaces and a topological proof the spin-statistics theorem which avoids quantum field theory and relativity. Under (1), after explaining the meaning of gauge invariance and the theory of constraints, we discuss boundary conditions on gauge transformations and the definition of internal symmetries in gauge field theories. We then show how the edge states in the quantum Hall effect can be derived from the Chern-Simons action using the preceding ideas. Under (2), after explaining the significance of fibre bundles for quantum physics, we review quantisation on multiply connected spaces in detail, explaining also mathematical ideas such as those of the universal covering space and the fundamental group. These ideas are then used to prove the aforementioned topological spin-statistics theorem

Gauge-invariant factorization and canonical quantization of topologically massive gauge theories in any dimension

International Nuclear Information System (INIS)

Bertrand, Bruno; Govaerts, Jan

2007-01-01

Abelian topologically massive gauge theories (TMGT) provide a topological mechanism to generate mass for a bosonic p-tensor field in any spacetime dimension. These theories include the (2+1)-dimensional Maxwell-Chern-Simons and (3+1)-dimensional Cremmer-Scherk actions as particular cases. Within the Hamiltonian formulation, the embedded topological field theory (TFT) sector related to the topological mass term is not manifest in the original phase space. However, through an appropriate canonical transformation, a gauge-invariant factorization of phase space into two orthogonal sectors is feasible. The first of these sectors includes canonically conjugate gauge-invariant variables with free massive excitations. The second sector, which decouples from the total Hamiltonian, is equivalent to the phase-space description of the associated non-dynamical pure TFT. Within canonical quantization, a likewise factorization of quantum states thus arises for the full spectrum of TMGT in any dimension. This new factorization scheme also enables a definition of the usual projection from TMGT onto topological quantum field theories in a most natural and transparent way. None of these results rely on any gauge-fixing procedure whatsoever

Evaluation of Contact Friction in Fracture of Rotationally Bent Nitinol Endodontic Files

Science.gov (United States)

Haimed, Tariq Abu

2011-12-01

The high flexibility of rotary Nitinol (Ni-Ti) files has helped clinicians perform root canal treatments with fewer technical errors than seen with stainless steel files. However, intracanal file fracture can occur, compromising the outcome of the treatment. Ni-Ti file fracture incidence is roughly around 4% amongst specialists and higher amongst general practitioners. Therefore, eliminating or reducing this problem should improve patient care. The aim of this project was to isolate and examine the role of friction between files and the canal walls of the glass tube model, and bending-related maximum strain amplitudes, on Ni-Ti file lifetimes-tofracture in the presence of different irrigant solutions and file coatings. A specifically designed device was used to test over 300 electropolished EndoSequenceRTM Ni-Ti files for number of cycles to failure (NCF) in smooth, bent glass tube models at 45 and 60 degrees during dry, coated and liquid-lubricated rotation at 600rpm. Fractured files were examined under Scanning Electron Microscopy (SEM) afterwards. Four different file sizes 25.04, 25.06, 35.04, 35.06 (diameter in mm/taper %) and six surface modification conditions were used independently. These conditions included, three solutions; (1) a surfactant-based solution, Surface-Active-Displacement-Solution (SADS), (2) a mouth wash proven to remove biofilms, Delmopinol 1%(DEL), and (3) Bleach 6% (vol.%), the most common antibacterial endodontic irrigant solution. The conditions also included two low-friction silane-based coating groups, 3-Hepta-fluoroisopropyl-propoxymethyl-dichlorosilane (3-HEPT) and Octadecyltrichlorosilane (ODS), in addition to an as-received file control group (Dry). The coefficient of friction (CF) between the file and the canal walls for each condition was measured as well as the surface tension of the irrigant solutions and the critical surface tension of the coated and uncoated files by contact angle measurements. The radius of curvature and

Diagrammatic cancellations and the gauge dependence of QED

Energy Technology Data Exchange (ETDEWEB)

Kißler, Henry, E-mail: kissler@physik.hu-berlin.de [Department of Mathematical Sciences, University of Liverpool, L69 7ZL, Liverpool (United Kingdom); Department of Mathematics, Humboldt-Universität zu Berlin, Rudower Chaussee 25, D-12489 Berlin (Germany); Kreimer, Dirk, E-mail: kreimer@math.hu-berlin.de [Department of Mathematics, Humboldt-Universität zu Berlin, Rudower Chaussee 25, D-12489 Berlin (Germany)

2017-01-10

This letter examines diagrammatic cancellations for Quantum Electrodynamics (QED) in the general linear gauge. These cancellations combine Feynman graphs of various topologies and provide a method to reconstruct the gauge dependence of the electron propagator from the result of a particular gauge by means of a linear Dyson–Schwinger equation. We use this method in combination with dimensional regularization to demonstrate how the 3-loop ε-expansion in the Feynman gauge determines the ε-expansions for all gauge parameter dependent terms to 4 loops.

Development of the Pirani and penning vacuum gauges

International Nuclear Information System (INIS)

Oh, B. H.; In, S. R.; Yoon, B. J.; Yoon, J. S.

2000-02-01

The Pirani and penning gauges developed during this study had made good characteristics compared with the measured results of customized other gauges, and this results show the possibility of developing the gauges by ourselves in Korea. In order to make a competition with the customized gauges of other countries, it is necessary to upgrade several points to have good characteristics over the large range of the pressure. The new efforts will be made in developing the full scale gauge in the next year. (author)

Development of the full range vange vacuum gauge

International Nuclear Information System (INIS)

Oh, B. H.; In, S. R.; Jung, K. S.; Jeong, S. H.

2001-01-01

The pirani, enning end full range gauges developed during this study had made good characteristics compared with the measured results of customized other gauges, and this results show the possibility of developing the gauges by ourselves in Korea. In order to make a competition with the customized gauges of other countries, it is necessary to upgrade several points to have good characteristics over the large range of the pressure. The new effort will be made in developing the full scale gauge in the next year

Holographic Gauge Mediation

Energy Technology Data Exchange (ETDEWEB)

Benini, Francesco; /Princeton U.; Dymarsky, Anatoly; /Stanford U., ITP; Franco, Sebastian; /Santa Barbara, KITP; Kachru, Shamit; Simic, Dusan; /Stanford U., ITP /SLAC; Verlinde, Herman; /Princeton, Inst. Advanced Study

2009-06-19

We discuss gravitational backgrounds where supersymmetry is broken at the end of a warped throat, and the SUSY-breaking is transmitted to the Standard Model via gauginos which live in (part of) the bulk of the throat geometry. We find that the leading effect arises from splittings of certain 'messenger mesons,' which are adjoint KK-modes of the D-branes supporting the Standard Model gauge group. This picture is a gravity dual of a strongly coupled field theory where SUSY is broken in a hidden sector and transmitted to the Standard Model via a relative of semi-direct gauge mediation.

Gauge theory for finite-dimensional dynamical systems

International Nuclear Information System (INIS)

Gurfil, Pini

2007-01-01

Gauge theory is a well-established concept in quantum physics, electrodynamics, and cosmology. This concept has recently proliferated into new areas, such as mechanics and astrodynamics. In this paper, we discuss a few applications of gauge theory in finite-dimensional dynamical systems. We focus on the concept of rescriptive gauge symmetry, which is, in essence, rescaling of an independent variable. We show that a simple gauge transformation of multiple harmonic oscillators driven by chaotic processes can render an apparently ''disordered'' flow into a regular dynamical process, and that there exists a strong connection between gauge transformations and reduction theory of ordinary differential equations. Throughout the discussion, we demonstrate the main ideas by considering examples from diverse fields, including quantum mechanics, chemistry, rigid-body dynamics, and information theory

Hidden diversity in bent-winged bats (Chiroptera: Miniopteridae) of the Western Palaearctic and adjacent regions: implications for taxonomy

Czech Academy of Sciences Publication Activity Database

Šrámek, J.; Gvoždík, Václav; Benda, P.

2013-01-01

Roč. 167, č. 1 (2013), s. 165-190 ISSN 0024-4082 R&D Projects: GA ČR(CZ) GA206/09/0888 Keywords : Arabia * bent-winged bats * cryptic species Subject RIV: EG - Zoology Impact factor: 2.658, year: 2013

Remarks on lattice gauge models

International Nuclear Information System (INIS)

Grosse, H.

1981-01-01

The author reports a study of the phase structure of lattice gauge models where one takes as a gauge group a non-abelian discrete subgroup of SU(3). In addition he comments on a lattice action proposed recently by Manton and observes that it violates a positivity property. (Auth.)

Gauge invariance of color confinement due to the dual Meissner effect caused by Abelian monopoles

International Nuclear Information System (INIS)

Suzuki, Tsuneo; Hasegawa, Masayasu; Ishiguro, Katsuya; Koma, Yoshiaki; Sekido, Toru

2009-01-01

The mechanism of non-Abelian color confinement is studied in SU(2) lattice gauge theory in terms of the Abelian fields and monopoles extracted from non-Abelian link variables without adopting gauge fixing. First, the static quark-antiquark potential and force are computed with the Abelian and monopole Polyakov loop correlators, and the resulting string tensions are found to be identical to the non-Abelian string tension. These potentials also show the scaling behavior with respect to the change of lattice spacing. Second, the profile of the color-electric field between a quark and an antiquark is investigated with the Abelian and monopole Wilson loops. The color-electric field is squeezed into a flux tube due to monopole supercurrent with the same Abelian color direction. The parameters corresponding to the penetration and coherence lengths show the scaling behavior, and the ratio of these lengths, i.e., the Ginzburg-Landau parameter, indicates that the vacuum type is near the border of the type 1 and type 2 (dual) superconductors. These results are summarized in which the Abelian fundamental charge defined in an arbitrary color direction is confined inside a hadronic state by the dual Meissner effect. As the color-neutral state in any Abelian color direction corresponds to the physical color-singlet state, this effect explains non-Abelian color confinement and supports the existence of a gauge-invariant mechanism of color confinement due to the dual Meissner effect caused by Abelian monopoles.

21 CFR 886.1420 - Ophthalmic lens gauge.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic lens gauge. 886.1420 Section 886.1420...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1420 Ophthalmic lens gauge. (a) Identification. An ophthalmic lens gauge is a calibrated device intended to manually measure the curvature of a...

Some physico-geometrical remarks on gauge fields

International Nuclear Information System (INIS)

Ikeda, S.

1976-01-01

The gauge fields introduced to accomplish gauge invariance under Poincare and Weyl gauge transformations in general relativity are found a new to be absorbed into the covariant derivative operators. Some torsional properties associated with them are also discussed in connection with the principle of minimally coupling and the equivalence principle

Review of lattice supersymmetry and gauge-gravity duality

International Nuclear Information System (INIS)

Joseph, Anosh

2015-12-01

We review the status of recent investigations on validating the gauge-gravity duality conjecture through numerical simulations of strongly coupled maximally supersymmetric thermal gauge theories. In the simplest setting, the gauge-gravity duality connects systems of D0-branes and black hole geometries at finite temperature to maximally supersymmetric gauged quantum mechanics at the same temperature. Recent simulations show that non-perturbative gauge theory results give excellent agreement with the quantum gravity predictions, thus proving strong evidence for the validity of the duality conjecture and more insight into quantum black holes and gravity.

Dynamical Messengers for Gauge Mediation

Energy Technology Data Exchange (ETDEWEB)

Hook, Anson; Torroba, Gonzalo; /SLAC /Stanford U., Phys. Dept.

2011-08-17

We construct models of indirect gauge mediation where the dynamics responsible for breaking supersymmetry simultaneously generates a weakly coupled subsector of messengers. This provides a microscopic realization of messenger gauge mediation where the messenger and hidden sector fields are unified into a single sector. The UV theory is SQCD with massless and massive quarks plus singlets, and at low energies it flows to a weakly coupled quiver gauge theory. One node provides the primary source of supersymmetry breaking, which is then transmitted to the node giving rise to the messenger fields. These models break R-symmetry spontaneously, produce realistic gaugino and sfermion masses, and give a heavy gravitino.

Lattice calculations in gauge theory

International Nuclear Information System (INIS)

Rebbi, C.

1985-01-01

The lattice formulation of quantum gauge theories is discussed as a viable technique for quantitative studies of nonperturbative effects in QCD. Evidence is presented to ascertain that whole classes of lattice actions produce a universal continuum limit. Discrepancies between numerical results from Monto Carlo simulations for the pure gauge system and for the system with gauge and quark fields are discussed. Numerical calculations for QCD require very substantial computational resources. The use of powerful vector processors of special purpose machines, in extending the scope and magnitude or the calculations is considered, and one may reasonably expect that in the near future good quantitative predictions will be obtained for QCD

Evolutionary algorithms applied to Landau-gauge fixing

International Nuclear Information System (INIS)

Markham, J.F.

1998-01-01

Current algorithms used to put a lattice gauge configuration into Landau gauge either suffer from the problem of critical slowing-down or involve an additions computational expense to overcome it. Evolutionary Algorithms (EAs), which have been widely applied to other global optimisation problems, may be of use in gauge fixing. Also, being global, they should not suffer from critical slowing-down as do local gradient based algorithms. We apply EA'S and also a Steepest Descent (SD) based method to the problem of Landau Gauge Fixing and compare their performance. (authors)

Non-minimal gauge mediation and moduli stabilization

International Nuclear Information System (INIS)

Jelinski, T.; Lalak, Z.; Pawelczyk, J.

2010-01-01

In this Letter we consider U(1) A -gauged Polonyi model with two spurions coupled to a twisted closed string modulus. This offers a consistent setup for metastable SUSY breakdown which allows for moduli stabilization and naturally leads to gauge or hybrid gauge/gravitational mediation mechanism. Due to the presence of the second spurion one can arrange for a solution of the μ and B μ problems in a version of modified Giudice-Masiero mechanism, which works both in the limit of pure gauge mediation and in the mixed regime of hybrid mediation.

Current status of nucleonic gauges in Portugal

International Nuclear Information System (INIS)

Salgado, J.; Carvalho, F.G.; Manteigas, J.; Oliveira, C.; Goncalves, I.F.; Neves, J.; Cruz, C.

2000-01-01

The nucleonic gauges are largely used in Portugal industry, despite the fact that design and manufacturing of prototypes of nucleonic gauges is rather limited. The modernization of some industrial sectors (cement, paper and civil engineering) has enhanced applications of nucleonic gauges and has created local capability but new legislation tends to restrict further spread of them. The Institute of Nuclear Technology is the only applied research institution developing nucleonic gauges for moisture, thickness and density, and elemental analysis, as well as providing assistance in calibration, safe operation and maintenance of them. (author)

Gauge Coupling Unification with Partly Composite Matter

International Nuclear Information System (INIS)

Gherghetta, Tony

2005-01-01

It is shown how gauge coupling unification can occur in models with partly composite matter. The particle states which are composite only contribute small logarithmns to the running of gauge couplings, while the elementary states contribute the usual large logarithmns. This introduces a new differential running contribution to the gauge couplings from partly composite SU(5) matter multiplets. In particular, for partly supersymmetric models, the incomplete SU(5) elementary matter multiplets restore gauge coupling unification even though the usual elementary gaugino and Higgsino contributions need not be present

Particle structure of gauge theories

International Nuclear Information System (INIS)

Fredenhagen, K.

1985-11-01

The implications of the principles of quantum field theory for the particle structure of gauge theories are discussed. The general structure which emerges is compared with that of the Z 2 Higgs model on a lattice. The discussion leads to several confinement criteria for gauge theories with matter fields. (orig.)

Remarks on lattice gauge models

International Nuclear Information System (INIS)

Grosse, H.

1981-01-01

The author reports on a study of the phase structure of lattice gauge models where one takes as a gauge group a non-abelian discrete subgroup of SU(3). In addition he comments on a lattice action proposed recently by Manton (1980) and observes that it violates a positivity property. (Auth.)

A Monte Carlo simulation on critical current distribution of bent-damaged multifilamentary Bi2223 composite tape

International Nuclear Information System (INIS)

Ochiai, S.; Okuda, H.; Fujimoto, M.; Shin, J.K.; Oh, S.S.; Ha, D.W.

2011-01-01

We simulate critical current distribution of bent-damaged Bi2223 composite tape. We use a Monte Carlo method and a damage evolution model for simulation. With the present simulation approach, experimental results are described well. Critical current distribution stems mainly from difference in damage evolution. It was attempted to reproduce the measured critical current (I c ) distributions of the Bi2223 composite tape bent by 0-0.833% by simulation. Simulation was carried out with a Monte Carlo method in combination with a model that correlates the critical current to damage evolution. Two variables that differ from specimen to specimen were input in the simulation. One was the damage strain parameter, with which the difference in extent of damage among specimens was expressed. Another was the original critical current (I c0 ) values at zero bending strain. With the present simulation approach, the measured distributions of critical current at various bending strains, and the measured variations of average and coefficient of variation of critical current values with increasing bending strain were reproduced well.

A gauge-invariant reorganization of thermal gauge theory

International Nuclear Information System (INIS)

Su, Nan

2010-01-01

This dissertation is devoted to the study of thermodynamics for quantum gauge theories. The poor convergence of quantum field theory at finite temperature has been the main obstacle in the practical applications of thermal QCD for decades. In this dissertation I apply hard-thermal-loop perturbation theory, which is a gauge-invariant reorganization of the conventional perturbative expansion for quantum gauge theories to the thermodynamics of QED and Yang-Mills theory to three-loop order. For the Abelian case, I present a calculation of the free energy of a hot gas of electrons and photons by expanding in a power series in m D /T, m f /T and e 2 , where m D and m f are the photon and electron thermal masses, respectively, and e is the coupling constant. I demonstrate that the hard-thermal-loop perturbation reorganization improves the convergence of the successive approximations to the QED free energy at large coupling, e ∝ 2. For the non-Abelian case, I present a calculation of the free energy of a hot gas of gluons by expanding in a power series in m D /T and g 2 , where m D is the gluon thermal mass and g is the coupling constant. I show that at three-loop order hard-thermal-loop perturbation theory is compatible with lattice results for the pressure, energy density, and entropy down to temperatures T ∝ 2 - 3 T c . The results suggest that HTLpt provides a systematic framework that can be used to calculate static and dynamic quantities for temperatures relevant at LHC. (orig.)

Primordial anisotropies in gauged hybrid inflation

Science.gov (United States)

Akbar Abolhasani, Ali; Emami, Razieh; Firouzjahi, Hassan

2014-05-01

We study primordial anisotropies generated in the model of gauged hybrid inflation in which the complex waterfall field is charged under a U(1)gauge field. Primordial anisotropies are generated either actively during inflation or from inhomogeneities modulating the surface of end of inflation during waterfall transition. We present a consistent δN mechanism to calculate the anisotropic power spectrum and bispectrum. We show that the primordial anisotropies generated at the surface of end of inflation do not depend on the number of e-folds and therefore do not produce dangerously large anisotropies associated with the IR modes. Furthermore, one can find the parameter space that the anisotropies generated from the surface of end of inflation cancel the anisotropies generated during inflation, therefore relaxing the constrains on model parameters imposed from IR anisotropies. We also show that the gauge field fluctuations induce a red-tilted power spectrum so the averaged power spectrum from the gauge field can change the total power spectrum from blue to red. Therefore, hybrid inflation, once gauged under a U(1) field, can be consistent with the cosmological observations.

Primordial anisotropies in gauged hybrid inflation

International Nuclear Information System (INIS)

Abolhasani, Ali Akbar; Emami, Razieh; Firouzjahi, Hassan

2014-01-01

We study primordial anisotropies generated in the model of gauged hybrid inflation in which the complex waterfall field is charged under a U(1)gauge field. Primordial anisotropies are generated either actively during inflation or from inhomogeneities modulating the surface of end of inflation during waterfall transition. We present a consistent δN mechanism to calculate the anisotropic power spectrum and bispectrum. We show that the primordial anisotropies generated at the surface of end of inflation do not depend on the number of e-folds and therefore do not produce dangerously large anisotropies associated with the IR modes. Furthermore, one can find the parameter space that the anisotropies generated from the surface of end of inflation cancel the anisotropies generated during inflation, therefore relaxing the constrains on model parameters imposed from IR anisotropies. We also show that the gauge field fluctuations induce a red-tilted power spectrum so the averaged power spectrum from the gauge field can change the total power spectrum from blue to red. Therefore, hybrid inflation, once gauged under a U(1) field, can be consistent with the cosmological observations

Emergent Gauge Fields in Holographic Superconductors

CERN Document Server

Domènech, Oriol; Pomarol, Alex; Salvio, Alberto; Silva, Pedro J

2010-01-01

Holographic superconductors have been studied so far in the absence of dynamical electromagnetic fields, namely in the limit in which they coincide with holographic superfluids. It is possible, however, to introduce dynamical gauge fields if a Neumann-type boundary condition is imposed on the AdS-boundary. In 3+1 dimensions, the dual theory is a 2+1 dimensional CFT whose spectrum contains a massless gauge field, signaling the emergence of a gauge symmetry. We study the impact of a dynamical gauge field in vortex configurations where it is known to significantly affect the energetics and phase transitions. We calculate the critical magnetic fields H_c1 and H_c2, obtaining that holographic superconductors are of Type II (H_c1 < H_c2). We extend the study to 4+1 dimensions where the gauge field does not appear as an emergent phenomena, but can be introduced, by a proper renormalization, as an external dynamical field. We also compare our predictions with those arising from a Ginzburg-Landau theory and identif...

Supersymmetry, quantum gauge anomalies and generalized Chern-Simons terms in chiral gauge theory

International Nuclear Information System (INIS)

Schmidt, Torsten

2009-01-01

The purpose of this thesis is to investigate the interplay of anomaly cancellation and generalized Chern-Simons terms in four-dimensional chiral gauge theory. We start with a detailed discussion of generalized Chern-Simons terms with the canellation of anomalies via the Green-Schwarz mechanism. With this at hand, we investigate the situation in general N=1 supersymmetric field theories with generalized Chern-Simons terms. Two simple consistency conditions are shown to encode strong constraints on the allowed anomalies for different types of gauge groups. In one major part of this thesis we are going to display to what extent one has to modify the existing formalism in order to allow for the cancellation of quantum gauge anomalies via the Green-Schwarz mechanism. At the end of this thesis we comment on a puzzle in the literature on supersymmetric field theories with massive tensor fields. The potential contains a term that does not arise from eliminating an auxiliary field. We clarify the origin of this term and display the relation to standard D-term potential. In an appendix it is explicitly shown how these low energy effective actions might be connected to the formulation of four-dimensional gauge theories discussed at earlier stages of this thesis. (orig.)