Grain Refinement in Al-Mg-Si Alloy TIG Welds Using Transverse Mechanical Arc Oscillation
NASA Astrophysics Data System (ADS)
Biradar, N. S.; Raman, R.
2012-11-01
Reduction in grain size in weld fusion zones (FZs) presents the advantages of increased resistance to solidification cracking and improvement in mechanical properties. Transverse mechanical arc oscillation was employed to obtain grain refinement in the weldment during tungsten inert gas welding of Al-Mg-Si alloy. Electron backscattered diffraction analysis was carried out on AA6061-AA4043 filler metal tungsten inert gas welds. Grain size, texture evolution, misorientation distribution, and aspect ratio of weld metal, PMZ, and BM have been observed at fixed arc oscillation amplitude and at three different frequencies levels. Arc oscillation showed grain size reduction and texture formation. Fine-grained arc oscillated welds exhibited better yield and ultimate tensile strengths and significant improvement in percent elongation. The obtained results were attributed to reduction in equivalent circular diameter of grains and increase in number of subgrain network structure of low angle grain boundaries.
Reich, Christoph Guttmann, Martin; Wernicke, Tim; Mehnke, Frank; Kuhn, Christian; Feneberg, Martin; Goldhahn, Rüdiger; Rass, Jens; Kneissl, Michael; Lapeyrade, Mickael; Einfeldt, Sven; Knauer, Arne; Kueller, Viola; Weyers, Markus
2015-10-05
The optical polarization of emission from ultraviolet (UV) light emitting diodes (LEDs) based on (0001)-oriented Al{sub x}Ga{sub 1−x}N multiple quantum wells (MQWs) has been studied by simulations and electroluminescence measurements. With increasing aluminum mole fraction in the quantum well x, the in-plane intensity of transverse-electric (TE) polarized light decreases relative to that of the transverse-magnetic polarized light, attributed to a reordering of the valence bands in Al{sub x}Ga{sub 1−x}N. Using k ⋅ p theoretical model calculations, the AlGaN MQW active region design has been optimized, yielding increased TE polarization and thus higher extraction efficiency for bottom-emitting LEDs in the deep UV spectral range. Using (i) narrow quantum wells, (ii) barriers with high aluminum mole fractions, and (iii) compressive growth on patterned aluminum nitride sapphire templates, strongly TE-polarized emission was observed at wavelengths as short as 239 nm.
NASA Astrophysics Data System (ADS)
Barone, Vincenzo; Ratcliffe, Philip G.
Introduction. Purpose and status of the Italian Transversity Project / F. Bradamante -- Opening lecture. Transversity / M. Anselmino -- Experimental lectures. Azimuthal single-spin asymmetries from polarized and unpolarized hydrogen targets at HERMES / G. Schnell (for the HERMES Collaboration). Collins and Sivers asymmetries on the deuteron from COMPASS data / I. Horn (for the COMPASS Collaboration). First measurement of interference fragmentation on a transversely polarized hydrogen target / P. B. van der Nat (for the HERMES Collaboration). Two-hadron asymmetries at the COMPASS experiment / A. Mielech (for the COMPASS Collaboration). Measurements of chiral-odd fragmentation functions at Belle / R. Seidl ... [et al.]. Lambda asymmetries / A. Ferrero (for the COMPASS Collaboration). Transverse spin at PHENIX: results and prospects / C. Aidala (for the PHENIX Collaboration). Transverse spin and RHIC / L. Bland. Studies of transverse spin effects at JLab / H. Avakian ... [et al.] (for the CLAS Collaboration). Neutron transversity at Jefferson Lab / J. P. Chen ... [et al.] (for the Jefferson Lab Hall A Collaboration). PAX: polarized antiproton experiments / M. Contalbrigo. Single and double spin N-N interactions at GSI / M. Maggiora (for the ASSIA Collaboration). Spin filtering in storage rings / N. N. Nikolaev & F. F. Pavlov -- Theory lectures. Single-spin asymmetries and transversity in QCD / S. J. Brodsky. The relativistic hydrogen atom: a theoretical laboratory for structure functions / X. Artru & K. Benhizia. GPD's and SSA's / M. Burkardt. Time reversal odd distribution functions in chiral models / A. Drago. Soffer bound and transverse spin densities from lattice QCD / M. Diehl ... [et al.]. Single-spin asymmetries and Qiu-Sterman effect(s) / A. Bacchetta. Sivers function: SIDIS data, fits and predictions / M. Anselmino ... [et al.]. Twist-3 effects in semi-inclusive deep inelastic scattering / M. Schlegel, K. Goeke & A. Metz. Quark and gluon Sivers functions / I
Intracavity Fourier-optical transverse mode selection in an AlGaInP broad-area laser
NASA Astrophysics Data System (ADS)
Wolff, Sandra; Messerschmidt, Dirk; Fouckhardt, Henning
1999-05-01
A Fourier-optical set-up within the external cavity of a commercially available broad-area laser diode to select certain transverse modes is investigated experimentally. The external cavity consists of a lens and a spatial frequency filter, the latter consisting of a reflecting slit (perpendicular to the active layer) surrounded by a darkened background. This is a Fourier-optical 4f set-up (2f plus reflection). The laser employed first is a partially antireflection coated 0.25 W 655 nm AlGaInP broad area laser. The free running laser shows non-stationary filamentation. Placing the slit directly onto the optical axis gives cw fundamental mode operation and a transverse shift of the spatial filter allows for selective excitation of higher order modes at low pump currents. Next, a highly antireflection coated 1.2 W 811 nm AlGaAs broad area laser is utilized in the 4f set-up. Selective excitation of higher order modes is achieved at high pump currents. Another approach to support fundamental mode operation uses a 2f set-up (1f plus reflection) consisting of a concave mirror at a distance f away from the laser facet. Here, the laser facet with its active region dimensions is the spatial filter. Also, the feasibility of autocatalytic mode coupling for reduction of unstable filamentation of broad-area lasers is examined experimentally.
NASA Astrophysics Data System (ADS)
Giuseppe, Ciullo; Paolo, Lenisa; Marco, Contalbrigo; Delia, Hasch
2009-04-01
Purpose and status of the Italian transversity project / F. Bradamante -- Transversity asymmetries / D. Boer -- The transverse angular momentum sum rule / E. Leader -- Measurement of Collins and Sivers asymmetries at HERMES / L. L. Pappalardo (for the HERMES collaboration) -- Review of SSA results on deuteron at COMPASS / A. Richter (for the COMPASS collaboration) -- Single spin asymmetries on a transversely polarized proton target at COMPASS / S. Levorato (for the COMPASS collaboration) -- New preliminary results on the transversity distribution and the Collins fragmentation functions / M. Anselmino ... [et al.] -- Sivers effect in SIDIS pion and kaon production / M. Anselmino ... [et al.] -- Spin-orbit correlations / M. Burkardt -- Correlation functions in hard and (semi)-inclusive processes / M. Schlegel, S. Mei[symbol]ner and A. Metz -- Transversity via exclusive [pie symbol]-electroproduction / G. R. Goldstein, S. Liuti and S. Ahmad -- Estimate of the Sivers asymmetry at intermediate energies with rescattering extracted from exclusive processes / A. Bianconi -- Exclusively produced p[symbol] asymmetries on the deuteron and future GPD measurements at COMPASS / C. Schill (for the COMPASS collaboration) -- Transversity and transverse-momentum-dependent distribution measurements from PHENIX and BRAHMS / C. Aidala (for the PHENIX and BRAHMS collaborations) -- Sivers and Collins effects in polarized pp scattering processes / M. Anselmino ... [et al.] -- Sivers function in constituent quark models / S. Scopetta ... [et al.] -- Sivers, Boer-Mulders and transversity in Drell-Yan processes / M. Anselmino ... [et al.] -- TMDs and Drell-Yan experiments at Fermilab and J-PARC / J.-C. Peng -- Double polarisation observables at PAX / M. Nekipelov (for the PAX collaboration) -- Future Drell-Yan measurement @ COMPASS / M. Colantoni (for the COMPASS collaboration) -- Measurements of unpolarized azimuthal asymmetries at COMPASS / W. Käfer (for the COMPASS collaboration
NASA Astrophysics Data System (ADS)
Shumilov, A. A.; Vinnichenko, M. Ya; Balagula, R. M.; Vorobjev, L. E.; Firsov, D. A.; Kulagina, M. M.; Vasil'iev, A. P.; Duque, C. A.; Tiutiunnyk, A.; Akimov, V.; Restrepo, R. L.; Tulupenko, V. N.; Ter-Martirosyan, A. L.
2015-11-01
Modulation of refraction index under transverse electric field was studied in structures with multiple tunnel-coupled GaAs/AlGaAs quantum wells in the spectral range corresponding to intersubband light absorption. The change of refraction index in electric field was calculated using Kramers-Kronig relation and experimentally determined spectra of intersubband light absorption in equilibrium conditions and under transverse electric field.
Transverse acoustic waves in piezoelectric ZnO/MgO and GaN/AlN Fibonacci-periodic superlattices
NASA Astrophysics Data System (ADS)
Martínez-Gutiérrez, D.; Velasco, V. R.
2014-06-01
This work studies the transverse acoustic waves, including the piezoelectric coupling, in Fibonacci superlattices formed by wurtzite ZnO/MgO and GaN/AlN, respectively. We examine also other superlattice structures formed by combining different kinds of Fibonacci sequences and finite periodic systems. The possibility to use different Fibonacci sequences including layers with double length of one of the constituent materials produces important modifications in the dispersion curves. The effect is more important in the lower frequency range and affects the gaps appearing in this frequency range. It is also possible to find narrow and flat bands cutting the original gaps and producing narrower ones. There are modes at different frequency ranges having spatial confinement in one of the constituent parts of the superlattice period.
Li, Xiao-Hang E-mail: dupuis@gatech.edu; Kao, Tsung-Ting; Satter, Md. Mahbub; Shen, Shyh-Chiang; Yoder, P. Douglas; Detchprohm, Theeradetch; Dupuis, Russell D. E-mail: dupuis@gatech.edu; Wei, Yong O.; Wang, Shuo; Xie, Hongen; Fischer, Alec M.; Ponce, Fernando A.
2015-01-26
We demonstrate transverse-magnetic (TM) dominant deep-ultraviolet (DUV) stimulated emission from photo-pumped AlGaN multiple-quantum-well lasers grown pseudomorphically on an AlN/sapphire template by means of photoluminescence at room temperature. The TM-dominant stimulated emission was observed at wavelengths of 239, 242, and 243 nm with low thresholds of 280, 250, and 290 kW/cm{sup 2}, respectively. In particular, the lasing wavelength of 239 nm is shorter compared to other reports for AlGaN lasers grown on foreign substrates including sapphire and SiC. The peak wavelength difference between the transverse-electric (TE)-polarized emission and TM-polarized emission was approximately zero for the lasers in this study, indicating the crossover of crystal-field split-off hole and heavy-hole valence bands. The rapid variation of polarization between TE- and TM-dominance versus the change in lasing wavelength from 243 to 249 nm can be attributed to a dramatic change in the TE-to-TM gain coefficient ratio for the sapphire-based DUV lasers in the vicinity of TE-TM switch.
Firsov, D. A.; Vorobjev, L. E.; Vinnichenko, M. Ya. Balagula, R. M.; Kulagina, M. M.; Vasil’iev, A. P.
2015-11-15
The photoluminescence and intersubband absorption spectra are studied in GaAs/AlGaAs tunnel- coupled quantum well structures. The peak positions in the photoluminescence and absorption spectra are consistent with the theoretically calculated energies of optical carrier transitions. The effect of a transverse electric field and temperature on intersubband light absorption is studied. It is caused by electron redistribution between the size-quantization levels and a variation in the energy spectrum of quantum wells. The variation in the refractive index in the energy region of observed intersubband transitions is estimated using Kramers–Kronig relations.
NASA Astrophysics Data System (ADS)
Hu, Y. Y.; Zhou, T. F.; Zheng, S. N.; Liu, X. H.; Zhao, J. J.; Su, X. J.; Huang, J.; Qiu, Y. X.; Zhang, J. C.; Xu, K.
2016-05-01
In this study, we present a microspectroscopic investigation on the quasi-transverse optical phonon modes Q(TO) in some self-generated aluminum nitride (AlN) grains grown on sapphire using hydride vapor phase epitaxy. Using X-ray diffraction and transmission electron microscope, these grains were confirmed to be embedded in (0001)-AlN (c-AlN) epitaxial matrix with an appearance plane of (10 1 ¯ 1 ) (s-plane). Two beam bright field images further showed that the AlN grains were free of dislocation. In-plane phonon anisotropy of the AlN grains was discussed in detail using angular-dependent polarized Raman spectroscopy. The dependence of pure Raman phonons intensity on rotation angle agrees well with the calculation. The Q(TO) phonon intensity exhibited similar behavior to that of A1(TO) phonon, which can be explained by Loudon's formula. However, the observed frequency fluctuation for the Q(TO) phonon differs from that of the pure phonon modes, which cannot be directly understood from the classic Loudon's formula. A modified Loudon's formula appropriate to non-normal incidence was presented to explain the observed Q(TO) phonon frequency fluctuation. Combining with the angular-dependent Raman spectra, we proposed that a small inclination of s-plane along with the various in-plane orientations in c-AlN matrix lead to the frequency fluctuation of Q(TO) in these embedded semipolar AlN grains.
Black, M.J.; Motaghedi, B.; Robitaille, Y.
1980-05-01
Transverse myelitis is a known complication of radiation treatment for carcinoma of the heat and neck. In a five year period, 1970 to 1975, 120 patients with head and neck cancer received radiation as part of their treatment in this hospital. A review of the records of these patients showed only two cases of myelitis, an incidence of about 2%. This paper reviews the clinical syndrome; treatment and preventive measures are discussed and a survey of the literature is presented.
Transverse Momentum Fluctuations at RHIC
NASA Astrophysics Data System (ADS)
Gavin, Sean; Abdel-Aziz, Mohamed
2004-10-01
PHENIX and STAR data in Au+Au collisions at RHIC show that transverse momentum fluctuations increase as centrality increases. The approach to local thermal equilibrium can explain the similar centrality dependence of the average transverse momentum and its fluctuations [1]. Alternatively, this dependence can be attributed to jet effects, although the mechanism has not been spelled out in the literature [2]. Certainly both mechanisms play a role at some level. We review the nonequilibrium description of parton thermalization in [1]. We then extend the formulation to account for contributions to fluctuations from the energy loss of the high transverse momentum particles. Calculations are then compared to the measured average transverse momentum and its fluctuations. We then discuss how correlation function measurements may distinguish these effects. [1] Sean Gavin, Phys.Rev.Lett. 92 (2004) 162301. [2] S. S. Adler et al. [PHENIX Collaboration], arXiv:nucl-ex/0310005.
Nakamura, Hiroyuki; Nakanishi, Hidekazu; Goto, Rei; Hashimoto, Ken-ya
2011-10-01
A SiO(2)/Al/LiNbO(3) structure has a large electromechanical coupling factor (K(2)) and good temperature coefficient of frequency (TCF) for applications as a SAW duplexer of the Universal Mobile Telecommunications System (UMTS) Band I. However, the SiO(2)/Al/LiNbO(3) structure also supports two unwanted spurious responses; one is caused by the Rayleigh mode and the other by the transverse mode. As the authors have previously discussed, the Rayleigh-mode spurious response can be suppressed by controlling the cross-sectional shape of a SiO(2) overlay deposited on resonator electrodes. In this paper, a new technique to suppress the transverse-mode spurious responses is proposed. In the technique, the SiO(2) overlay is selectively removed from the dummy electrode region. The spurious responses are analyzed by the laser probe system. The results indicate that the spurious responses in question were hybrid modes caused by the coupling between the main (SH) SAW and another (Rayleigh) SAW with different velocities. The hybrid-mode spurious behavior was dependent on the velocities in the IDT and the dummy regions (v(i) and v(d)). The hybrid-mode spurious responses could be suppressed by selectively removing SiO(2). Furthermore, the SAW energy confinement could be enhanced in the IDT electrode region when v(i) < v(d). The transverse-mode spurious responses were successfully suppressed without degrading the SAW resonator performances. PMID:21989882
Transverse spin and transverse momentum in scattering of plane waves
NASA Astrophysics Data System (ADS)
Saha, Sudipta; Singh, Ankit K.; Ray, Subir K.; Banerjee, Ayan; Gupta, Subhasish Dutta; Ghosh, Nirmalya
2016-10-01
We study the near field to the far field evolution of spin angular momentum (SAM) density and the Poynting vector of the scattered waves from spherical scatterers. The results show that at the near field, the SAM density and the Poynting vector are dominated by their transverse components. While the former (transverse SAM) is independent of the helicity of the incident circular polarization state, the latter (transverse Poynting vector) depends upon the polarization state. It is further demonstrated that the magnitudes and the spatial extent of the transverse SAM and the transverse momentum components can be controllably enhanced by exploiting the interference of the transverse electric and transverse magnetic scattering modes.
Transverse colon conduit diversion
Schmidt, J.D.; Buchsbaum, H.J.
1986-05-01
The versatility and other advantages of the transverse colon conduit for urinary diversion have been described and implemented in 50 patients. Because most patients considered for this procedure will be at high risk because of a history of significant pelvic irradiation, underlying malignancy, poor renal function, fistula, and so forth, the technical details of surgery and patient selection cannot be minimized. The transverse colon segment is indicated for primary supravesical diversion as well as for salvage of problems related to ileal conduits. Adenocarcinoma of the colon is an unlikely long-term complication of this form of diversion because the fecal stream is absent. Now that the transverse colon conduit has been used for more than 10 years, meaningful comparisons with ileal segments should soon be available.
Nondiffracting transversally polarized beam.
Yuan, G H; Wei, S B; Yuan, X-C
2011-09-01
Generation of a nondiffracting transversally polarized beam by means of transmitting an azimuthally polarized beam through a multibelt spiral phase hologram and then highly focusing by a high-NA lens is presented. A relatively long depth of focus (∼4.84λ) of the electric field with only radial and azimuthal components is achieved. The polarization of the wavefront near the focal plane is analyzed in detail by calculating the Stokes polarization parameters. It is found that the polarization is spatially varying and entirely transversally polarized, and the polarization singularity disappears at the beam center, which makes the central bright channel possible. PMID:21886250
Transverse Bursts in Inclined Layer Convection: Experiment
NASA Astrophysics Data System (ADS)
Daniels, Karen; Wiener, Richard; Bodenschatz, Eberhard
2002-03-01
We report experimental results on inclined layer convection in a fluid of Prandtl number σ ≈ 1. A codimension-two point divides regions of buoyancy-driven convection (longitudinal rolls) at lower angles from shear-driven convection (transverse rolls) at higher angles (Daniels et al. PRL 84: 5320, 2000). In the region of buoyancy-driven convection, near the codimension-two point, we observe longitudinal rolls with intermittent, localized, subharmonic transverse bursts. The patterns are spatiotemporally chaotic. With increasing temperature difference the bursts increase in duration and number. We examine the details of the bursting process (e.g. the energy of longitudinal, transverse, and mixed modes) and compare our results to bursting processes in other systems. This work is supported by the National Science Foundation under grant DMR-0072077 and the IGERT program in nonlinear systems, grant DGE-9870631.
NASA Astrophysics Data System (ADS)
Wang, Xiaorong
2016-03-01
In recent years, there has been exciting development in both experimental and theoretical studies of transverse spin asymmetries in polarized p+p and and DIS collisions. As a unique polarized proton-proton collider, Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) provides a unique opportunity to investigate the novel physics mechanisms that cause the large single spin asymmetry at the forward rapidity. Both PHENIX and STAR experiments have been studying the transverse spin asymmetries with a variety of final state particles in different kinematic regimes since 2006. Especially, recent theoretical development on scattering a polarized probe on the saturated nuclear may provide a unique way to probe the gluon and quark TMDs. RHIC successfully ran polarized p+Au collisions in 2015. We will expect to have new results from polarized d+Au to compare with existing results from p+p collision to extend our understanding of QCD. Further more, In 2015, PHENIX installed MPC-ex calorimeter at very forward region to measure direct photon AN and STAR installed Roman Pots to study the diffractive events in polarized p+p and p+Au collisions. The recent results on transverse polarized p+p and p+Au collisions from both PHENIX and STAR experiments will be presented in this talk. I will also briefly discuss the possibility for the transverse Spin program at future experiments sPHENIX and forward sPHENIX at RHIC. Supported by US Department of Energy and RIKEN Brookhaven Research Center.
Partonic Transverse Momentum Distributions
Rossi, Patrizia
2010-08-04
In recent years parton distributions have been generalized to account also for transverse degrees of freedom and new sets of more general distributions, Transverse Momentum Dependent (TMD) parton distributions and fragmentation functions were introduced. Different experiments worldwide (HERMES, COMPASS, CLAS, JLab-Hall A) have measurements of TMDs in semi-inclusive DIS processes as one of their main focuses of research. TMD studies are also an important part of the present and future Drell-Yan experiments at RICH and JPARC and GSI, respectively, Studies of TMDs are also one of the main driving forces of the Jefferson Lab (JLab) 12 GeV upgrade project. Progress in phenomenology and theory is flourishing as well. In this talk an overview of the latest developments in studies of TMDs will be given and newly released results, ongoing activities, as well as planned near term and future measurements will be discussed.
Transverse testicular ectopia.
Yıldız, Abdullah; Yiğiter, Murat; Oral, Akgün; Bakan, Vedat
2014-02-01
Described herein are six cases of transverse testicular ectopia. All patients who underwent orchidopexy at the one pediatric surgical unit between October 2001 and January 2008 were evaluated. The medical records of all patients diagnosed with transverse testicular ectopia were evaluated retrospectively. Five patients (84%) were admitted with a symptomatic right inguinal hernia and empty scrotum on the left side. Only one child (16%) had left-sided hernia and right non-palpable testis (age ranged from 1 month to 3 years). Four patients (66%) were diagnosed in the operating theatre and the last two (33%) on inguinal ultrasound preoperatively. Magnetic resonance imaging was also performed in the last patient. Herniorrhaphy with fixation of the ectopic gonad to the opposite hemiscrotum through a transseptal incision was performed in all patients. Postoperative complications were not observed. PMID:24548194
Neutron Transversity at Jefferson Lab
Jian-Ping Chen; Xiaodong Jiang; Jen-chieh Peng; Lingyan Zhu
2005-09-07
Nucleon transversity and single transverse spin asymmetries have been the recent focus of large efforts by both theorists and experimentalists. On-going and planned experiments from HERMES, COMPASS and RHIC are mostly on the proton or the deuteron. Presented here is a planned measurement of the neutron transversity and single target spin asymmetries at Jefferson Lab in Hall A using a transversely polarized {sup 3}He target. Also presented are the results and plans of other neutron transverse spin experiments at Jefferson Lab. Finally, the factorization for semi-inclusive DIS studies at Jefferson Lab is discussed.
Transverse field focused system
Anderson, Oscar A.
1986-01-01
A transverse field focused (TFF) system for transport or acceleration of an intense sheet beam of negative ions in which a serial arrangement of a plurality of pairs of concentric cylindrical-arc electrodes is provided. Acceleration of the sheet beam can be achieved by progressively increasing the mean electrode voltage of successive electrode pairs. Because the beam is curved by the electrodes, the system can be designed to transport the beam through a maze passage which is baffled to prevent line of sight therethrough. Edge containment of the beam can be achieved by shaping the side edges of the electrodes to produce an electric force vector directed inwardly from the electrode edges.
Transverse Compression of Tendons.
Salisbury, S T Samuel; Buckley, C Paul; Zavatsky, Amy B
2016-04-01
A study was made of the deformation of tendons when compressed transverse to the fiber-aligned axis. Bovine digital extensor tendons were compression tested between flat rigid plates. The methods included: in situ image-based measurement of tendon cross-sectional shapes, after preconditioning but immediately prior to testing; multiple constant-load creep/recovery tests applied to each tendon at increasing loads; and measurements of the resulting tendon displacements in both transverse directions. In these tests, friction resisted axial stretch of the tendon during compression, giving approximately plane-strain conditions. This, together with the assumption of a form of anisotropic hyperelastic constitutive model proposed previously for tendon, justified modeling the isochronal response of tendon as that of an isotropic, slightly compressible, neo-Hookean solid. Inverse analysis, using finite-element (FE) simulations of the experiments and 10 s isochronal creep displacement data, gave values for Young's modulus and Poisson's ratio of this solid of 0.31 MPa and 0.49, respectively, for an idealized tendon shape and averaged data for all the tendons and E = 0.14 and 0.10 MPa for two specific tendons using their actual measured geometry. The compression load versus displacement curves, as measured and as simulated, showed varying degrees of stiffening with increasing load. This can be attributed mostly to geometrical changes in tendon cross section under load, varying according to the initial 3D shape of the tendon. PMID:26833218
Transverse Compression of Tendons.
Salisbury, S T Samuel; Buckley, C Paul; Zavatsky, Amy B
2016-04-01
A study was made of the deformation of tendons when compressed transverse to the fiber-aligned axis. Bovine digital extensor tendons were compression tested between flat rigid plates. The methods included: in situ image-based measurement of tendon cross-sectional shapes, after preconditioning but immediately prior to testing; multiple constant-load creep/recovery tests applied to each tendon at increasing loads; and measurements of the resulting tendon displacements in both transverse directions. In these tests, friction resisted axial stretch of the tendon during compression, giving approximately plane-strain conditions. This, together with the assumption of a form of anisotropic hyperelastic constitutive model proposed previously for tendon, justified modeling the isochronal response of tendon as that of an isotropic, slightly compressible, neo-Hookean solid. Inverse analysis, using finite-element (FE) simulations of the experiments and 10 s isochronal creep displacement data, gave values for Young's modulus and Poisson's ratio of this solid of 0.31 MPa and 0.49, respectively, for an idealized tendon shape and averaged data for all the tendons and E = 0.14 and 0.10 MPa for two specific tendons using their actual measured geometry. The compression load versus displacement curves, as measured and as simulated, showed varying degrees of stiffening with increasing load. This can be attributed mostly to geometrical changes in tendon cross section under load, varying according to the initial 3D shape of the tendon.
Transversity quark distributions in a covariant quark-diquark model
I.C. Cloet; W. Bentz; A.W. Thomas
2008-01-01
Transversity quark light-cone momentum distributions are calculated for the nucleon. We utilize a modified Nambu--Jona-Lasinio model in which confinement is simulated by eliminating unphysical thresholds for nucleon decay into quarks. The nucleon bound state is obtained by solving the relativistic Faddeev equation in the quark-diquark approximation, where both scalar and axial-vector diquark channels are included. Particular attention is paid to comparing our results with the recent experimental extraction of the transversity distributions by Anselmino et al. We also compare our transversity results with earlier spin-independent and helicity quark distributions calculated in the same approach.
NASA Astrophysics Data System (ADS)
Matta, J. T.; Garg, U.; Li, W.; Frauendorf, S.; Ayangeakaa, A. D.; Patel, D.; Schlax, K. W.; Palit, R.; Saha, S.; Sethi, J.; Trivedi, T.; Ghugre, S. S.; Raut, R.; Sinha, A. K.; Janssens, R. V. F.; Zhu, S.; Carpenter, M. P.; Lauritsen, T.; Seweryniak, D.; Chiara, C. J.; Kondev, F. G.; Hartley, D. J.; Petrache, C. M.; Mukhopadhyay, S.; Lakshmi, D. Vijaya; Raju, M. Kumar; Madhusudhana Rao, P. V.; Tandel, S. K.; Ray, S.; Dönau, F.
2015-02-01
A pair of transverse wobbling bands is observed in the nucleus 135Pr . The wobbling is characterized by Δ I =1 , E 2 transitions between the bands, and a decrease in the wobbling energy confirms its transverse nature. Additionally, a transition from transverse wobbling to a three-quasiparticle band comprised of strong magnetic dipole transitions is observed. These observations conform well to results from calculations with the tilted axis cranking model and the quasiparticle rotor model.
Transverse Spin Effects at COMPASS
Wollny, H.
2009-08-04
The measurement of transverse spin effects in semi-inclusive deep-inelastic scattering (SIDIS) is an important part of the COMPASS physics program. In the years 2002-2004 data was taken by scattering a 160 GeV/c muon beam off a transversely polarized deuteron target. In 2007, additional data was collected on a transversely polarized proton target. New preliminary results for the Collins and Sivers asymmetries from the analysis of the proton data are presented.
Pediatric transverse myelitis.
Absoud, Michael; Greenberg, Benjamin M; Lim, Ming; Lotze, Tim; Thomas, Terrence; Deiva, Kumaran
2016-08-30
Pediatric acute transverse myelitis (ATM) is an immune-mediated CNS disorder and contributes to 20% of children experiencing a first acquired demyelinating syndrome (ADS). ATM must be differentiated from other presentations of myelopathy and may be the first presentation of relapsing ADS such as neuromyelitis optica (NMO) or multiple sclerosis (MS). The tenets of the diagnostic criteria for ATM established by the Transverse Myelitis Consortium Working Group can generally be applied in children; however, a clear sensory level may not be evident in some. MRI lesions are often centrally located with high T2 signal intensity involving gray and neighboring white matter. Longitudinally extensive ATM occurs in the majority. Asymptomatic lesions on brain MRI are seen in more than one-third and predict MS or NMO. The role of antibodies such as myelin oligodendrocyte glycoprotein in monophasic and relapsing ATM and their significance in therapeutic approaches remain unclear. ATM is a potentially devastating condition with variable outcome and presents significant cumulative demands on health and social care resources. Children generally have a better outcome than adults, with one-half making a complete recovery by 2 years. There is need for standardization of clinical assessment and investigation protocols to enable international collaborative studies to delineate prognostic factors for disability and relapse. There are no robust controlled trials in children or adults to inform optimal treatment of ATM, with one study currently open to recruitment. This review provides an overview of current knowledge of clinical features, investigative workup, pathogenesis, and management of ATM and suggests future directions. PMID:27572861
General formulation of transverse hydrodynamics
Ryblewski, Radoslaw; Florkowski, Wojciech
2008-06-15
General formulation of hydrodynamics describing transversally thermalized matter created at the early stages of ultrarelativistic heavy-ion collisions is presented. Similarities and differences with the standard three-dimensionally thermalized relativistic hydrodynamics are discussed. The role of the conservation laws as well as the thermodynamic consistency of two-dimensional thermodynamic variables characterizing transversally thermalized matter is emphasized.
Kinesthetic Transverse Wave Demonstration
NASA Astrophysics Data System (ADS)
Pantidos, Panagiotis; Patapis, Stamatis
2005-09-01
This is a variation on the String and Sticky Tape demonstration "The Wave Game," suggested by Ron Edge. A group of students stand side by side, each one holding a card chest high with both hands. The teacher cues the first student to begin raising and lowering his card. When he starts lowering his card, the next student begins to raise his. As succeeding students move their cards up and down, a wave such as that shown in the figure is produced. To facilitate the process, students' motions were synchronized with the ticks of a metronome (without such synchronization it was nearly impossible to generate a satisfactory wave). Our waves typically had a frequency of about 1 Hz and a wavelength of around 3 m. We videotaped the activity so that the students could analyze the motions. The (17-year-old) students had not received any prior instruction regarding wave motion and did not know beforehand the nature of the exercise they were about to carry out. During the activity they were asked what a transverse wave is. Most of them quickly realized, without teacher input, that while the wave propagated horizontally, the only motion of the transmitting medium (them) was vertical. They located the equilibrium points of the oscillations, the crests and troughs of the waves, and identified the wavelength. The teacher defined for them the period of the oscillations of the motion of a card to be the total time for one cycle. The students measured this time and then several asserted that it was the same as the wave period. Knowing the length of the waves and the number of waves per second, the next step can easily be to find the wave speed.
New construction for transversal design.
Du, Ding-Zhu; Hwang, F K; Wu, Weili; Znati, Taieb
2006-05-01
The study of gene functions requires the development of a DNA library of high quality through much of testing and screening. Pooling design is a mathematical tool to reduce the number of tests for DNA library screening. The transversal design is a special type of pooling design, which is good in implementation. In this paper, we present a new construction for transversal designs. We will also extend our construction to the error-tolerant case.
TRANSVERSE OSCILLATIONS IN CHROMOSPHERIC MOTTLES
Kuridze, D.; Mathioudakis, M.; Jess, D. B.; Keenan, F. P.; Morton, R. J.; Erdelyi, R.; Dorrian, G. D.
2012-05-01
A number of recent investigations have revealed that transverse waves are ubiquitous in the solar chromosphere. The vast majority of these have been reported in limb spicules and active region fibrils. We investigate long-lived, quiet-Sun, on-disk features such as chromospheric mottles (jet-like features located at the boundaries of supergranular cells) and their transverse motions. The observations were obtained with the Rapid Oscillations in the Solar Atmosphere instrument at the Dunn Solar Telescope. The data set is comprised of simultaneous imaging in the H{alpha} core, Ca II K, and G band of an on-disk quiet-Sun region. Time-distance techniques are used to study the characteristics of the transverse oscillations. We detect over 40 transverse oscillations in both bright and dark mottles, with periods ranging from 70 to 280 s, with the most frequent occurrence at {approx}165 s. The velocity amplitudes and transverse displacements exhibit characteristics similar to limb spicules. Neighboring mottles oscillating in-phase are also observed. The transverse oscillations of individual mottles are interpreted in terms of magnetohydrodynamic kink waves. Their estimated periods and damping times are consistent with phase mixing and resonant mode conversion.
Transverse deformations of extreme horizons
NASA Astrophysics Data System (ADS)
Li, Carmen; Lucietti, James
2016-04-01
We consider the inverse problem of determining all extreme black hole solutions to the Einstein equations with a prescribed near-horizon geometry. We investigate this problem by considering infinitesimal deformations of the near-horizon geometry along transverse null geodesics. We show that, up to a gauge transformation, the linearised Einstein equations reduce to an elliptic PDE for the extrinsic curvature of a cross-section of the horizon. We deduce that for a given near-horizon geometry there exists a finite dimensional moduli space of infinitesimal transverse deformations. We then establish a uniqueness theorem for transverse deformations of the extreme Kerr horizon. In particular, we prove that the only smooth axisymmetric transverse deformation of the near-horizon geometry of extreme Kerr, such that cross-sections of the horizon are marginally trapped surfaces, corresponds to that of the extreme Kerr black hole. Furthermore, we determine all smooth and biaxisymmetric transverse deformations of the near-horizon geometry of the five-dimensional extreme Myers-Perry black hole with equal angular momenta. We find a three parameter family of solutions such that cross-sections of the horizon are marginally trapped, which is more general than the known black hole solutions. We discuss the possibility that they correspond to new five-dimensional vacuum black holes.
Flutter analysis using transversality theory
NASA Technical Reports Server (NTRS)
Afolabi, D.
1993-01-01
A new method of calculating flutter boundaries of undamped aeronautical structures is presented. The method is an application of the weak transversality theorem used in catastrophe theory. In the first instance, the flutter problem is cast in matrix form using a frequency domain method, leading to an eigenvalue matrix. The characteristic polynomial resulting from this matrix usually has a smooth dependence on the system's parameters. As these parameters change with operating conditions, certain critical values are reached at which flutter sets in. Our approach is to use the transversality theorem in locating such flutter boundaries using this criterion: at a flutter boundary, the characteristic polynomial does not intersect the axis of the abscissa transversally. Formulas for computing the flutter boundaries and flutter frequencies of structures with two degrees of freedom are presented, and extension to multi-degree of freedom systems is indicated. The formulas have obvious applications in, for instance, problems of panel flutter at supersonic Mach numbers.
Transverse modes in microchip lasers
Sanchez, F.; Chardon, A.
1996-12-01
Two analytical sets of transverse eigenmodes are proposed for microchip lasers in one-dimensional geometry. Each set is associated with a particular pump profile. The eigenfunctions are expressed as Bessel or modified Bessel functions. {copyright} {ital 1996 Optical Society of America.}
Small, D.W.; Wong, R.K.; Colson, W.B.
1995-12-31
In an ultraviolet Free Electron Laser (UV FEL), the electron beam size can be approximately the same as the optical mode size. The performance of a UV FEL is studied including the effect of emittance, betatron focusing, and external focusing of the electron beam on the transverse optical mode. The results are applied to the Industrial Laser Consortium`s UV FEL.
Transverse Magnetic Field Propellant Isolator
NASA Technical Reports Server (NTRS)
Foster, John E.
2000-01-01
An alternative high voltage isolator for electric propulsion and ground-based ion source applications has been designed and tested. This design employs a transverse magnetic field that increases the breakdown voltage. The design can greatly enhance the operating range of laboratory isolators used for high voltage applications.
Transverse angular momentum of photons
Aiello, Andrea
2010-05-15
We develop the quantum theory of transverse angular momentum of light beams. The theory applies to paraxial and quasiparaxial photon beams in vacuum and reproduces the known results for classical beams when applied to coherent states of the field. Both the Poynting vector, alias the linear momentum, and the angular-momentum quantum operators of a light beam are calculated including contributions from first-order transverse derivatives. This permits a correct description of the energy flow in the beam and the natural emergence of both the spin and the angular momentum of the photons. We show that for collimated beams of light, orbital angular-momentum operators do not satisfy the standard commutation rules. Finally, we discuss the application of our theory to some concrete cases.
Transverse spin effects at COMPASS
Pesaro, G.
2009-03-23
The COMPASS experiment at the CERN SPS has a broad physics program focused on the nucleon spin structure and on hadron spectroscopy, using both muon and hadron beams. One of the main objectives for the spin program with the muon beam is the measurement of transverse spin effects in semi inclusive deep inelastic scattering. A longitudinally polarized 160 GeV/c muon beam is impinging on a transversely polarized target: from 2002 to 2004 a {sup 6}LiD(deuteron) target has been used, while during 2007 data taking a NH{sub 3}(proton) target was put in place. All measured transverse asymmetries on deuteron have been found to be small, and compatible with zero, within the few percent statistical errors. These results, which are currently used as input for global fits, can be interpreted as cancellation between u and d quark contribution in the deuteron. The first results for the Collins and Sivers asymmetries for charged hadrons from the 2007 proton COMPASS data are also presented and discussed.
QCD Evolution of Helicity and Transversity TMDs
Prokudin, Alexei
2014-01-01
We examine the QCD evolution of the helicity and transversity parton distribution functions when including also their dependence on transverse momentum. Using an appropriate definition of these polarized transverse momentum distributions (TMDs), we describe their dependence on the factorization scale and rapidity cutoff, which is essential for phenomenological applications.
Transverse Force on Quarks in DIS
Burkardt, Matthias
2009-01-01
The $x^2$-moment of the twist-3 polarized parton distribution $g_2(x)$ is related to the transverse force acting on the active quark in deep-inelastic scattering off a transversely polarized nucleon immediately after it has absorbed the virtual photon. Lattice calculations of the corresponding matrix element as well as experimental measurements of $g_2(x)$ are used to estimate sign and magnitude of this force. Similarly, the $x^2$-moment of the chirally odd twist-3 unpolarized parton distribution $e(x)$ can be related to the transverse force experienced by a transversely polarized quark ejected from a transversely polarized nucleon.
Transverse Momentum Dependent Distributions in Hard Scattering
Alexie Prokudin
2011-05-01
Transverse Momentum Dependent Distributions (TMDs) describe the spin structure of the proton. At leading twist spin structure of spin-1/2 hadron can be described by 8 TMDs. TMDs reveal three-dimensional distribution of partons inside polarised nucleon. Experimentally these functions can be studied in polarised experiments using Spin Asymmetries in particular Single Spin Asymmetries (SSAs). We discuss transversity that measures distribution of transversely polarised quarks in a transversely polarised nucleon and Sivers distribution function that describes distribution of unpolarised quarks in a transversely polarised nucleon.
A new fifth parameter for transverse isotropy
NASA Astrophysics Data System (ADS)
Kawakatsu, H.
2015-12-01
Kawakatsu et al. (2015) recently proposed a new parameter, ¥eta¥kappa that properly characterizes the incidence angle dependence (relative to the symmetry axis) of seismic bodywaves in a transverse isotropy (TI) system. While the commonly used fifth parameter in global seismology to describe TI system, ¥eta=F/(A-2L) , has no simple physical meaning, the newly defined parameter, ¥[¥eta_{¥kappa} = ¥frac{F+L}{ (A-L)^{1/2}(C-L)^{1/2} } ,¥] where A, C, F and L denote the Love's elastic constants for TI, measures the departure from the ``elliptic condition" (Thomsen, 1986) when ¥eta¥kappa not equal to unity, and characterizes nicely the incidence angle dependence of bodywaves. When existing models of upper mantle radial anisotropy are compared in terms of this new parameter, PREM shows a distinct property. Within the anisotropic layer of PREM (a depth range of 24.4-220km), ¥eta¥kappa < 1 in the top half and ¥eta¥kappa > 1 in the lower half. If ¥eta¥kappa > 1, anisotropy cannot be attributed to the layering of homogeneous layers. While how well the fifth parameter is constrained from data needs to be carefully examined, we now have, at least, a parameter that properly characterizes the TI system. I suggest (hope) this parameter to be used in future surface wave and bodywave studiesof the mantle anisotropy, rather than the conventional ¥eta.¥bigskip¥noindent{¥bf Reference:} ¥¥¥noindentKawakatsu, H, J-P Montagner, and T-R A Song, On DLA's ¥eta, in The Interdisciplinary Earth: A volume in honor of Don L. Anderson, edited by Foulger et al., GSA, in press (2015).
Transverse Echo Measurements in RHIC
Fischer, Wolfram
2006-03-20
Diffusion counteracts cooling and the knowledge of diffusion rates is important for the calculation of cooling times and equilibrium beam sizes. Echo measurements are a potentially sensitive method to determine diffusion rates, and longitudinal measurements were done in a number of machines. We report on transverse echo measurements in RHIC and the observed dependence of echo amplitudes on a number of parameters for beams of gold and copper ions, and protons. In particular we examine the echo amplitudes of gold and copper ion bunches of varying intensity, which exhibit different diffusion rates from intrabeam scattering.
TRANSVERSE ECHO MEASUREMENTS IN RHIC.
FISCHER, W.
2005-09-18
Diffusion counteracts cooling and the knowledge of diffusion rates is important for the calculation of cooling times and equilibrium beam sizes. Echo measurements are a potentially sensitive method to determine diffusion rates, and longitudinal measurements were done in a number of machines. We report on transverse echo measurements in RHIC and the observed dependence of echo amplitudes on a number of parameters for beams of gold and copper ions, and protons. In particular they examine the echo amplitudes of gold and copper ion bunches of varying intensity, which exhibit different diffusion rates from intrabeam scattering.
A Transversely Isotropic Thermoelastic Theory
NASA Technical Reports Server (NTRS)
Arnold, S. M.
1989-01-01
A continuum theory is presented for representing the thermoelastic behavior of composites that can be idealized as transversely isotropic. This theory is consistent with anisotropic viscoplastic theories being developed presently at NASA Lewis Research Center. A multiaxial statement of the theory is presented, as well as plane stress and plane strain reductions. Experimental determination of the required material parameters and their theoretical constraints are discussed. Simple homogeneously stressed elements are examined to illustrate the effect of fiber orientation on the resulting strain distribution. Finally, the multiaxial stress-strain relations are expressed in matrix form to simplify and accelerate implementation of the theory into structural analysis codes.
A new fifth parameter for transverse isotropy
NASA Astrophysics Data System (ADS)
Kawakatsu, Hitoshi
2016-04-01
Kawakatsu et al. (2015) recently proposed a new parameter, ηκ that properly characterizes the incidence angle dependence (relative to the symmetry axis) of seismic bodywaves in a transverse isotropy (TI) system. While the commonly used fifth parameter in global seismology to describe TI system, η = F/(A - 2L), has no simple physical meaning, the newly defined parameter, ηκ = (F + L)/[(A - L)1/2(C - L)1/2] where A, C, F and L denote the Love's elastic constants for TI, measures the departure from the "elliptic condition" when ηκ not equal to unity, and characterizes nicely the incidence angle dependence of bodywaves. When existing models of upper mantle radial anisotropy are compared in terms of this new parameter, PREM shows a distinct property. Within the anisotropic layer of PREM (a depth range of 24.4-220km), ηκ < 1 in the top half and ηκ > 1 in the lower half. If ηκ > 1, anisotropy cannot be attributed to the layering of homogeneous layers, and thus requires the presence of intrinsic anisotropy (Kawakatsu, 2016). To further investigate significance of the new parameter for long-period seismology, partial derivatives of surface wave phase velocity and normal mode eigen-frequency for the new set of five parameters are examined. The partial derivative for ηκ is about twice as large as that for the conventional η, indicating that ηκ is more resolved than is usually considered. While partial derivatives for (anisotropic) S-velocities are not so changed, those for (anisotropic) P-velocities are significantly modified; the sensitivity for anisotropic P-velocities is greatly reduced. In contrary to Dziewonski and Anderson (1981)'s suggestion, there is not much control on the anisotropic P-velocities. The significance of ηκ for the long-period seismology has been shown. While how well the fifth parameter is constrained from data needs to be carefully examined, we now have, at least, a parameter that properly characterizes the TI system. This
A new fifth parameter for transverse isotropy
NASA Astrophysics Data System (ADS)
Kawakatsu, Hitoshi
2016-04-01
Kawakatsu et al. (2015) recently proposed a new parameter, ηκ that properly characterizes the incidence angle dependence (relative to the symmetry axis) of seismic bodywaves in a transverse isotropy (TI) system. While the commonly used fifth parameter in global seismology to describe TI system, η = F/(A ‑ 2L), has no simple physical meaning, the newly defined parameter, ηκ = (F + L)/[(A ‑ L)1/2(C ‑ L)1/2] where A, C, F and L denote the Love's elastic constants for TI, measures the departure from the "elliptic condition" when ηκ not equal to unity, and characterizes nicely the incidence angle dependence of bodywaves. When existing models of upper mantle radial anisotropy are compared in terms of this new parameter, PREM shows a distinct property. Within the anisotropic layer of PREM (a depth range of 24.4-220km), ηκ < 1 in the top half and ηκ > 1 in the lower half. If ηκ > 1, anisotropy cannot be attributed to the layering of homogeneous layers, and thus requires the presence of intrinsic anisotropy (Kawakatsu, 2016). To further investigate significance of the new parameter for long-period seismology, partial derivatives of surface wave phase velocity and normal mode eigen-frequency for the new set of five parameters are examined. The partial derivative for ηκ is about twice as large as that for the conventional η, indicating that ηκ is more resolved than is usually considered. While partial derivatives for (anisotropic) S-velocities are not so changed, those for (anisotropic) P-velocities are significantly modified; the sensitivity for anisotropic P-velocities is greatly reduced. In contrary to Dziewonski and Anderson (1981)'s suggestion, there is not much control on the anisotropic P-velocities. The significance of ηκ for the long-period seismology has been shown. While how well the fifth parameter is constrained from data needs to be carefully examined, we now have, at least, a parameter that properly characterizes the TI system. This
Transverse Bursts in Inclined Layer Convection: Theory
NASA Astrophysics Data System (ADS)
Bodenschatz, Eberhard; Brink, Jeandrew; Pesch, Werner
2002-03-01
We report theoretical and computational results on thermally driven inclined layer convection. For small Prandtl number fluids, experiments have reported bursting phenomena at both small angles, strong driving and high angles, weak driving (Daniels et al. PRL 84: 5320, 2000). Theoretically, the small angle, strong driving case was described by Clever and Busse (Physics of Fluids 12: 2137, 2000) and was connected to a subharmonic instability. At large angles, close to the codimension-two point, intermittent, localized, transverse subharmonic bursts occur at weak driving. Qualitatively, the bursts draw energy from the roll modes, exhaust them while growing, and die out when they are unable to find a new attractor. We investigate a connection between the small- and large-angle bursts. Using Galerkin methods and direct simulations of the underlying Boussinesq equations, we examine the extent to which they are related to a linear instability of the roll pattern. We address a possible connection to the shear flow turbulent bursts observed in Taylor-Couette flow. In addition, we present a theoretical analysis of the small Prandtl number case, for which the codimension-two point moves to zero angle. This work is supported by a Cornell Graduate Student Fellowship and by the National Science Foundation under grant DMR-0072077.
RF cavities with transversely biased ferrite tuning
Smythe, W.R.; Brophy, T.G.; Carlini, R.D.; Friedrichs, C.C.; Grisham, D.L.; Spalek, G.; Wilkerson, L.C.
1985-10-01
Earley et al. suggested that ferrite tuned rf cavities have lower ferrite power dissipation if the ferrite bias field is perpendicular rather than parallel to the rf magnetic field. A 50-84 MHz cavity has been constructed in which ferrite can be biased either way. Low power measurements of six microwave ferrites show that the magnetic Q's of these ferrites under perpendicular bias are much higher than under parallel bias, and that the high Q region extends over a much wider range of rf permeability. TDK Y-5 ferrite was found to have a magnetic Q of 10,800, 4,800, 1,200 and 129 at rf permeabilities of 1.2, 2.4, 3.7 and 4.5, respectively. Measurements of perpendicularly biased ferrite at various power levels were made in a coaxial line cavity. The Q of Y-5 ferrite was found to decrease by less than a factor of 2 as the power density in the ferrite was increased to 1.3 W/cmT. A cavity design for a 6 GeV, high current, rapid cycling synchrotron using transversely biased ferrite tuning is described.
Transverse-longitudinal integrated resonator
Hutchinson, Donald P [Knoxville, TN; Simpson, Marcus L [Knoxville, TN; Simpson, John T [Knoxville, TN
2003-03-11
A transverse-longitudinal integrated optical resonator (TLIR) is disclosed which includes a waveguide, a first and a second subwavelength resonant grating in the waveguide, and at least one photonic band gap resonant structure (PBG) in the waveguide. The PBG is positioned between the first and second subwavelength resonant gratings. An electro-optic waveguide material may be used to permit tuning the TLIR and to permit the TLIR to perform signal modulation and switching. The TLIR may be positioned on a bulk substrate die with one or more electronic and optical devices and may be communicably connected to the same. A method for fabricating a TLIR including fabricating a broadband reflective grating is disclosed. A method for tuning the TLIR's transmission resonance wavelength is also disclosed.
Transverse section radionuclide scanning system
Kuhl, David E.; Edwards, Roy Q.
1976-01-01
This invention provides a transverse section radionuclide scanning system for high-sensitivity quantification of brain radioactivity in cross-section picture format in order to permit accurate assessment of regional brain function localized in three-dimensions. High sensitivity crucially depends on overcoming the heretofore known raster type scanning, which requires back and forth detector movement involving dead-time or partial enclosure of the scan field. Accordingly, this invention provides a detector array having no back and forth movement by interlaced detectors that enclose the scan field and rotate as an integral unit around one axis of rotation in a slip ring that continuously transmits the detector data by means of laser emitting diodes, with the advantages that increased amounts of data can be continuously collected, processed and displayed with increased sensitivity according to a suitable computer program.
Gluonic transversity from lattice QCD
NASA Astrophysics Data System (ADS)
Detmold, W.; Shanahan, P. E.
2016-07-01
We present an exploratory study of the gluonic structure of the ϕ meson using lattice QCD (LQCD). This includes the first investigation of gluonic transversity via the leading moment of the twist-2 double-helicity-flip gluonic structure function Δ (x ,Q2). This structure function only exists for targets of spin J ≥1 and does not mix with quark distributions at leading twist, thereby providing a particularly clean probe of gluonic degrees of freedom. We also explore the gluonic analogue of the Soffer bound which relates the helicity flip and nonflip gluonic distributions, finding it to be saturated at the level of 80%. This work sets the stage for more complex LQCD studies of gluonic structure in the nucleon and in light nuclei where Δ (x ,Q2) is an "exotic glue" observable probing gluons in a nucleus not associated with individual nucleons.
Transversal magnetoresistance in Weyl semimetals
NASA Astrophysics Data System (ADS)
Klier, J.; Gornyi, I. V.; Mirlin, A. D.
2015-11-01
We explore theoretically the magnetoresistivity of three-dimensional Weyl and Dirac semimetals in transversal magnetic fields within two alternative models of disorder: (i) short-range impurities and (ii) charged (Coulomb) impurities. Impurity scattering is treated using the self-consistent Born approximation. We find that an unusual broadening of Landau levels leads to a variety of regimes of the resistivity scaling in the temperature-magnetic field plane. In particular, the magnetoresistance is nonmonotonous for the white-noise disorder model. For H →0 the magnetoresistance for short-range impurities vanishes in a nonanalytic way as H1 /3. In the limits of strongest magnetic fields H , the magnetoresistivity vanishes as 1 /H for pointlike impurities, while it is linear and positive in the model with Coulomb impurities.
Theory of Transverse Spin and Transverse Structure of the Nucleon
NASA Astrophysics Data System (ADS)
Koike, Yuji
2009-10-01
Large single transverse spin asymmetries (SSA) observed in various collision processes opened a new window to disentangle QCD dynamics and quark-gluon substructure of the nucleon. Since SSA is a ``naively T-odd'' observable, it can only occur as an interference between the scattering amplitudes which have different complex phases in a time-reversal invariant theory like QCD. A conventional framework for hard inclusive processes, i.e. perturbative QCD in the twist-2 level, can only give rise to a negligible asymmetry and thus can not explain the observed data. Understanding the origin of the large SSAs requires the extention of the framework of the QCD hard processes, and by now QCD mechanisms leading to large SSAs have been clarified in greater detail. These mechanisms based on different perspectives introduce new concepts describing the nucleon structure not present in the conventional parton model, such as ``parton's intrinsic transverse momentum'' and ``multi-parton correlations.'' Precise and unambiguous definition of these ideas requires much more careful theoretical analyses than the twist-2 case, in particular, in connection with the universality of the parton distribution/fragmentation functions, gauge invariance and factorization properties of the cross sections. In the literature, QCD mechanisms for SSAs are often classified into two categories. One is based on the (naively) ``T-odd'' distribution and fragmentation functions in the transverse momentum dependent (TMD) factorization approach. Sivers and Collins functions are typical examples for this one. The other one is based on the twist-3 quark-gluon (more generally, multi-parton such as triple-gluon) correlation functions in the collinear factorization approaches. The former mechanism can describe SSAs in the small-pT region (pTQ) as a leading-twist effect, while the latter one describes SSAs in the large pT region as a twist-3 effect. Both approaches have been applied to study SSAs in various
Evolution of the helicity and transversity Transverse-Momentum-Dependent parton distributions
Prokudin, Alexei; Bacchetta, Alessandro
2013-07-01
We examine the QCD evolution of the helicity and transversity parton distribution functions when including also their dependence on transverse momentum. Using an appropriate definition of these polarized transverse momentum distributions (TMDs), we describe their dependence on the factorization scale and rapidity cutoff, which is essential for phenomenological applications.
Evolution of the helicity and transversity Transverse-Momentum-Dependent parton distributions
Prokudin, Alexey; Bacchetta, Alessandro
2013-10-01
We examine the QCD evolution of the helicity and transversity parton distribution functions when including also their dependence on transverse momentum. Using an appropriate definition of these polarized transverse momentum distributions (TMDs), we describe their dependence on the factorization scale and rapidity cutoff, which is essential for phenomenological applications.
Cladding For Transversely-Pumped Laser Rod
NASA Technical Reports Server (NTRS)
Byer, Robert L.; Fan, Tso Yee
1989-01-01
Combination of suitable dimensioning and cladding of neodymium:yttrium aluminum garnet of similar solid-state laser provides for more efficient utilization of transversely-incident pump light from diode lasers. New design overcomes some of limitations of longitudinal- and older transverse-pumping concepts and promotes operation at higher output powers in TEM00 mode.
Transverse instability at the recycler ring
Ng, K.Y.; /Fermilab
2004-10-01
Sporadic transverse instabilities have been observed at the Fermilab Recycler Ring leading to increase in transverse emittances and beam loss. The driving source of these instabilities has been attributed to the resistive-wall impedance with space-charge playing an important role in suppressing Landau damping. Growth rates of the instabilities are computed. Remaining problems are discussed.
Recent COMPASS Results on Transverse Physics
Iwata, Takahiro; Collaboration: COMPASS Collaboration
2011-12-14
The investigation of transverse spin and transverse momentum dependent effects in deep inelastic scattering of muons off nucleons is one of the key physics programs of the COMPASS collaboration at CERN. We have investigated the effects from the data obtained with a polarized proton target. In order to access the transversity distribution function, following channels have been analyzed: The azimuthal distribution of single hadrons, the azimuthal dependence of the plane containing hadron pairs, and the measurement of the transverse polarization of lambda hyperons in the final state. The Sivers distribution function which is one of the transverse momentum dependent functions has been investigated also from the azimuthal distribution of single hadrons. Azimuthal asymmetries in unpolarized deep inelastic scattering give important information on the inner structure of the nucleon to access the so-far unmeasured Boer-Mulders function. We have measured these asymmetries using spin-averaged {sup 6}L{sub i}D.
Transverse Spin Effects in SIDIS at COMPASS
Joosten, Rainer
2009-12-17
The measurement of single spin asymmetries in semi-inclusive deep-inelastic scattering (SIDIS) on a transversely polarized target is an important part of the COMPASS physics program. It allows us to investigate the transversity distribution functions as well as transverse momentum dependent distribution functions by measuring azimuthal asymmetries in the hadron production. After COMPASS took data in the years 2002-2004 by scattering a 160 GeV/c muon beam off a transversely polarized deuteron ({sup 6}LiD) target, in 2007 additional data was collected on a transversely polarized proton (NH{sub 3}) target. In this contribution, the latest results on the Collins and Sivers asymmetries in single hadron production as well as two-hadron asymmetries from the analysis of the proton data are presented and compared with existing model predictions.
Recent COMPASS Results on Transverse Physics
NASA Astrophysics Data System (ADS)
Iwata, Takahiro
2011-12-01
The investigation of transverse spin and transverse momentum dependent effects in deep inelastic scattering of muons off nucleons is one of the key physics programs of the COMPASS collaboration at CERN. We have investigated the effects from the data obtained with a polarized proton target. In order to access the transversity distribution function, following channels have been analyzed: The azimuthal distribution of single hadrons, the azimuthal dependence of the plane containing hadron pairs, and the measurement of the transverse polarization of lambda hyperons in the final state. The Sivers distribution function which is one of the transverse momentum dependent functions has been investigated also from the azimuthal distribution of single hadrons. Azimuthal asymmetries in unpolarized deep inelastic scattering give important information on the inner structure of the nucleon to access the so-far unmeasured Boer-Mulders function. We have measured these asymmetries using spin-averaged 6LiD.
Electrodeposited, Transverse Nanowire Electroluminescent Junctions.
Qiao, Shaopeng; Xu, Qiang; Dutta, Rajen K; Le Thai, Mya; Li, Xiaowei; Penner, Reginald M
2016-09-27
The preparation by electrodeposition of transverse nanowire electroluminescent junctions (tn-ELJs) is described, and the electroluminescence (EL) properties of these devices are characterized. The lithographically patterned nanowire electrodeposition process is first used to prepare long (millimeters), linear, nanocrystalline CdSe nanowires on glass. The thickness of these nanowires along the emission axis is 60 nm, and the width, wCdSe, along the electrical axis is adjustable from 100 to 450 nm. Ten pairs of nickel-gold electrical contacts are then positioned along the axis of this nanowire using lithographically directed electrodeposition. The resulting linear array of nickel-CdSe-gold junctions produces EL with an external quantum efficiency, EQE, and threshold voltage, Vth, that depend sensitively on wCdSe. EQE increases with increasing electric field and also with increasing wCdSe, and Vth also increases with wCdSe and, therefore, the electrical resistance of the tn-ELJs. Vth down to 1.8(±0.2) V (for wCdSe ≈ 100 nm) and EQE of 5.5(±0.5) × 10(-5) (for wCdSe ≈ 450 nm) are obtained. tn-ELJs produce a broad EL emission envelope, spanning the wavelength range from 600 to 960 nm.
Orbital angular momentum and generalized transverse momentum distribution
NASA Astrophysics Data System (ADS)
Zhao, Yong; Liu, Keh-Fei; Yang, Yi-Bo
2016-03-01
We show that, when boosted to the infinite momentum frame, the quark and gluon orbital angular momentum operators defined in the nucleon spin sum rule of Chen et al. are the same as those whose matrix elements correspond to the moments of generalized transverse momentum distributions. This completes the connection between the infinite momentum limit of each term in that sum rule and experimentally measurable observables. We also show that these orbital angular momentum operators can be defined locally and discuss the strategies of calculating them in lattice QCD.
Transverse-Type Short-Circuited Thermoelements
NASA Astrophysics Data System (ADS)
Anatychuk, L. I.; Kobylyansky, R. R.
2012-06-01
This work reports on the results of theoretical and experimental research of short-circuited thermoelements (SCTE). Computer simulation was used to obtain the electric potential, current, and temperature distributions in the bulk of thermoelements. Computer optimization of such a thermoelement design was carried out to achieve maximum transverse thermoelectromotive force (thermoEMF) and efficiency. Experimental studies of the short-circuited thermoelements were pursued. Bi-Te alloys were used as the thermoelectric material. It was established that, among the transverse-type thermoelements, double short-circuited thermoelements achieve the highest values of transverse thermoEMF and efficiency.
Transverse Emittance Reduction with Tapered Foil
Jiao, Yi; Chao, Alex; Cai, Yunhai; /SLAC
2011-12-09
The idea of reducing transverse emittance with tapered energy-loss foil is proposed by J.M. Peterson in 1980s and recently by B. Carlsten. In this paper, we present the physical model of tapered energy-loss foil and analyze the emittance reduction using the concept of eigen emittance. The study shows that, to reduce transverse emittance, one should collimate at least 4% of particles which has either much low energy or large transverse divergence. The multiple coulomb scattering is not trivial, leading to a limited emittance reduction ratio. Small transverse emittances are of essential importance for the accelerator facilities generating free electron lasers, especially in hard X-ray region. The idea of reducing transverse emittance with tapered energy-loss foil is recently proposed by B. Carlsten [1], and can be traced back to J.M. Peterson's work in 1980s [2]. Peterson illustrated that a transverse energy gradient can be produced with a tapered energy-loss foil which in turn leads to transverse emittance reduction, and also analyzed the emittance growth from the associated multiple coulomb scattering. However, what Peterson proposed was rather a conceptual than a practical design. In this paper, we build a more complete physical model of the tapered foil based on Ref. [2], including the analysis of the transverse emittance reduction using the concept of eigen emittance and confirming the results by various numerical simulations. The eigen emittance equals to the projected emittance when there is no cross correlation in beam's second order moments matrix [3]. To calculate the eigen emittances, it requires only to know the beam distribution at the foil exit. Thus, the analysis of emittance reduction and the optics design of the subsequent beam line section can be separated. In addition, we can combine the effects of multiple coulomb scattering and transverse energy gradient together in the beam matrix and analyze their net effect. We find that,when applied to an
Transverse Colon Diverticulitis with Calcified Fecalith
Solak, Aynur; Solak, Ilhami; Genç, Berhan; Sahin, Neslin; Yalaz, Seyhan
2013-01-01
Left colonic diverticula are common in Western populations, whereas right colonic diverticulosis primarily occurs in Oriental populations. Diverticulitis of the transverse colon is very rare, with very few cases reported in the literature. Herein, we report a case of transverse colon diverticulitis caused by a calcified stone in a 69-year-old female. This was a solitary diverticulum. The signs and symptoms of the disease are similar to acute pancreatitis. To the best of our knowledge, this is the first report describing the MRI findings of a patient with trans-verse colon diverticulitis caused by a calcified stone. PMID:25610254
Ferroelectric Cathodes in Transverse Magnetic Fields
Alexander Dunaevsky; Yevgeny Raitses; Nathaniel J. Fisch
2002-07-29
Experimental investigations of a planar ferroelectric cathode in a transverse magnetic field up to 3 kGs are presented. It is shown that the transverse magnetic field affects differently the operation of ferroelectric plasma cathodes in ''bright'' and ''dark'' modes in vacuum. In the ''bright'' mode, when the surface plasma is formed, the application of the transverse magnetic field leads to an increase of the surface plasma density. In the ''dark'' mode, the magnetic field inhibits the development of electron avalanches along the surface, as it does similarly in other kinds of surface discharges in the pre-breakdown mode.
Estimation of shear viscosity based on transverse momentum correlations
NASA Astrophysics Data System (ADS)
STAR Collaboration; Sharma, Monika; STAR Collaboration
2009-11-01
Event anisotropy measurements at RHIC suggest the strongly interacting matter created in heavy ion collisions flows with very little shear viscosity. Precise determination of “shear viscosity-to-entropy” ratio is currently a subject of extensive study [S. Gavin and M. Abdel-Aziz, Phys. Rev. Lett. 97 (2006) 162302]. We present preliminary results of measurements of the evolution of transverse momentum correlation function with collision centrality of Au+Au interactions at s=200 GeV. We compare two differential correlation functions, namely inclusive [J. Adams et al. (STAR Collaboration), Phys. Rev. C 72 (2005) 044902] and a differential version of the correlation measure C˜ introduced by Gavin et al. [S. Gavin and M. Abdel-Aziz, Phys. Rev. Lett. 97 (2006) 162302; M. Sharma and C. A. Pruneau, Phys. Rev. C 79 (2009) 024905.]. These observables can be used for the experimental study of the shear viscosity per unit entropy.
Development of Transverse Modes Damped DLA Structure
Jing, C.; Kanareykin, A.; Schoessow, P.; Gai, W.; Konecny, R.; Power, J. G.; Conde, M.
2009-01-22
As the dimensions of accelerating structures become smaller and beam intensities higher, the transverse wakefields driven by the beam become quite large with even a slight misalignment of the beam from the geometric axis. These deflection modes can cause inter-bunch beam breakup and intra-bunch head-tail instabilities along the beam path, and thus BBU control becomes a critical issue. All new metal based accelerating structures, like the accelerating structures developed at SLAC or power extractors at CLIC, have designs in which the transverse modes are heavily damped. Similarly, minimizing the transverse wakefield modes (here the HEMmn hybrid modes in Dielectric-Loaded Accelerating (DLA) structures) is also very critical for developing dielectric based high energy accelerators. In this paper, we present the design of a 7.8 GHz transverse mode damped DLA structure currently under construction, along with plans for the experimental program.
Transverse damping systems in modern synchrotrons
NASA Astrophysics Data System (ADS)
Zhabitsky, V. M.
2006-12-01
Transverse feedback systems for suppression of transverse coherent beam oscillations are used in modern synchrotrons for preventing the development of transverse instabilities and damping residual beam oscillations after injection. Information on damper systems for the Large Hadron Collider (LHC; CERN, Geneva) and the accelerator complex FAIR (GSI, Darmstadt) is presented. The project for the LHC is being performed at the Laboratory of Particle Physics of the Joint Institute for Nuclear Research in collaboration with CERN. The information concerning the state of the project and the plans of its completion at the LHC is given. The results of the first design activity on transverse damping systems at the SIS100 and SIS300 synchrotrons, to be created in the framework of the new international project FAIR, are presented.
Transversally periodic solitary gravity-capillary waves.
Milewski, Paul A; Wang, Zhan
2014-01-01
When both gravity and surface tension effects are present, surface solitary water waves are known to exist in both two- and three-dimensional infinitely deep fluids. We describe here solutions bridging these two cases: travelling waves which are localized in the propagation direction and periodic in the transverse direction. These transversally periodic gravity-capillary solitary waves are found to be of either elevation or depression type, tend to plane waves below a critical transverse period and tend to solitary lumps as the transverse period tends to infinity. The waves are found numerically in a Hamiltonian system for water waves simplified by a cubic truncation of the Dirichlet-to-Neumann operator. This approximation has been proved to be very accurate for both two- and three-dimensional computations of fully localized gravity-capillary solitary waves. The stability properties of these waves are then investigated via the time evolution of perturbed wave profiles. PMID:24399922
Transversally periodic solitary gravity-capillary waves.
Milewski, Paul A; Wang, Zhan
2014-01-01
When both gravity and surface tension effects are present, surface solitary water waves are known to exist in both two- and three-dimensional infinitely deep fluids. We describe here solutions bridging these two cases: travelling waves which are localized in the propagation direction and periodic in the transverse direction. These transversally periodic gravity-capillary solitary waves are found to be of either elevation or depression type, tend to plane waves below a critical transverse period and tend to solitary lumps as the transverse period tends to infinity. The waves are found numerically in a Hamiltonian system for water waves simplified by a cubic truncation of the Dirichlet-to-Neumann operator. This approximation has been proved to be very accurate for both two- and three-dimensional computations of fully localized gravity-capillary solitary waves. The stability properties of these waves are then investigated via the time evolution of perturbed wave profiles.
Chronic Osteomyelitis of the Lumbar Transverse Process
Lee, Bong-Jin; Yoon, Min Geun; Kim, Sung-Soo; Moon, Myung-Sang
2011-01-01
Pyogenic spondylitis involving only the posterior element of a vertebra is rare. To the best of our knowledge, there have been no reports of osteomyelitis of the transverse process. We report here on a 45-year-old male with a one month history of swelling associated with lower back pain. The magnetic resonance imaging showed a paraspinal soft tissue mass, and computed tomography revealed a fine osteolytic lesion in the right transverse process of the 5th lumbar spine, and this was all consistent with chronic osteomyelitis. A mixed staphylococcal infection was identified. Open drainage, resection of the transverse process and intravenous injection of anti-staphylococcal antibiotics resolved the back pain and reduced the erythrocyte sedimentation rate to normal. Pyogenic osteomyelitis of the transverse process is extremely rare, which can cause a misdiagnosis or a delayed diagnosis. Careful consideration of this disease is needed when evaluating patients who complain of back pain. PMID:21909475
Exploring the transverse spin structure of the nucleon
D'Alesio, Umberto
2008-10-13
We discuss our present understanding of the transverse spin structure of the nucleon and of related properties originating from parton transverse motion. Starting from the transversity distribution and the ways to access it, we then address the role played by spin and transverse momentum dependent (TMD) distributions in azimuthal and transverse single spin asymmetries. The latest extractions of the Sivers, Collins and transversity functions are also presented.
Chiral dynamics and peripheral transverse densities
Granados, Carlos G.; Weiss, Christian
2014-01-01
In the partonic (or light-front) description of relativistic systems the electromagnetic form factors are expressed in terms of frame-independent charge and magnetization densities in transverse space. This formulation allows one to identify the chiral components of nucleon structure as the peripheral densities at transverse distances b = O(M{sub {pi}}{sup -1}) and compute them in a parametrically controlled manner. A dispersion relation connects the large-distance behavior of the transverse charge and magnetization densities to the spectral functions of the Dirac and Pauli form factors near the two--pion threshold at timelike t = 4 M{ sub {pi}}{sup 2}, which can be computed in relativistic chiral effective field theory. Using the leading-order approximation we (a) derive the asymptotic behavior (Yukawa tail) of the isovector transverse densities in the "chiral" region b = O(M{sub {pi}}{sup -1}) and the "molecular" region b = O(M{sub N}{sup 2}/M{sub {pi}}{sup 3}); (b) perform the heavy-baryon expansion of the transverse densities; (c) explain the relative magnitude of the peripheral charge and magnetization densities in a simple mechanical picture; (d) include Delta isobar intermediate states and study the peripheral transverse densities in the large-N{ sub c} limit of QCD; (e) quantify the region of transverse distances where the chiral components of the densities are numerically dominant; (f) calculate the chiral divergences of the b{sup 2}-weighted moments of the isovector transverse densities (charge and anomalous magnetic radii) in the limit M{sub {pi}} -> 0 and determine their spatial support. Our approach provides a concise formulation of the spatial structure of the nucleon's chiral component and offers new insights into basic properties of the chiral expansion. It relates the information extracted from low-t elastic form factors to the generalized parton distributions probed in peripheral high-energy scattering processes.
Transverse pelvic rotation during quiet human stance.
Günther, Michael; Otto, Daniel; Müller, Otto; Blickhan, Reinhard
2008-04-01
The mechanism of two-legged quiet stance is unclear. This study specifically investigated biomechanical parameters characterising the mechanisms of rotation around the longitudinal axis (parallel to gravitational acceleration, i.e. in the transverse plane parallel to the ground). Subjects (10) were examined while standing quietly on two force platforms which measured the transverse component of the ground reaction torque (GRT). In addition, right and left hip kinematics were acquired by tracking markers in the sagittal plane. The pelvic rotation in the transverse plane (pelvic angle) was then calculated from the anterior-posterior coordinates of the hip markers. We verified the hypothesis that the pelvis generally may be coupled to the ground by a rotational stiffness provided by both legs. Thus, we asked whether the transverse GRT component may be proportional to the pelvic angle. This hypothesis was rejected. However, the transverse GRT component could be identified as one rotational stabilising mechanism which drove the higher-frequency (>1 Hz) deflections of the pelvic angle back to its lower-frequency fraction. The respective stiffness coefficient between transverse GRT component and relative displacement between higher- and lower-frequency pelvic angular fraction was about 2.4 Nm/degrees. Implications for the character and the localisation of active control of body rotation around the longitudinal axis are discussed.
Transverse structure of the QCD string
Meyer, Harvey B.
2010-11-15
The characterization of the transverse structure of the QCD string is discussed. We formulate a conjecture as to how the stress-energy tensor of the underlying gauge theory couples to the string degrees of freedom. A consequence of the conjecture is that the energy density and the longitudinal-stress operators measure the distribution of the transverse position of the string, to leading order in the string fluctuations, whereas the transverse-stress operator does not. We interpret recent numerical measurements of the transverse size of the confining string and show that the difference of the energy and longitudinal-stress operators is a particularly natural probe at next-to-leading order. Second, we derive the constraints imposed by open-closed string duality on the transverse structure of the string. We show that a total of three independent ''gravitational'' form factors characterize the transverse profile of the closed string, and obtain the interpretation of recent effective string theory calculations: the square radius of a closed string of length {beta} defined from the slope of its gravitational form factor, is given by (d-1/2{pi}{sigma})log({beta}/4r{sub 0}) in d space dimensions. This is to be compared with the well-known result that the width of the open string at midpoint grows as (d-1/2{pi}{sigma})log(r/r{sub 0}). We also obtain predictions for transition form factors among closed-string states.
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Transverse and longitudinal angular momenta of light
NASA Astrophysics Data System (ADS)
Bliokh, Konstantin Y.; Nori, Franco
2015-08-01
We review basic physics and novel types of optical angular momentum. We start with a theoretical overview of momentum and angular momentum properties of generic optical fields, and discuss methods for their experimental measurements. In particular, we describe the well-known longitudinal (i.e., aligned with the mean momentum) spin and orbital angular momenta in polarized vortex beams. Then, we focus on the transverse (i.e., orthogonal to the mean momentum) spin and orbital angular momenta, which were recently actively discussed in theory and observed in experiments. First, the recently-discovered transverse spin angular momenta appear in various structured fields: evanescent waves, interference fields, and focused beams. We show that there are several kinds of transverse spin angular momentum, which differ strongly in their origins and physical properties. We describe extraordinary features of the transverse optical spins and overview recent experiments. In particular, the helicity-independent transverse spin inherent in edge evanescent waves offers robust spin-direction coupling at optical interfaces (the quantum spin Hall effect of light). Second, we overview the transverse orbital angular momenta of light, which can be both extrinsic and intrinsic. These two types of the transverse orbital angular momentum are produced by spatial shifts of the optical beams (e.g., in the spin Hall effect of light) and their Lorentz boosts, respectively. Our review is underpinned by a unified theory of the angular momentum of light based on the canonical momentum and spin densities, which avoids complications associated with the separation of spin and orbital angular momenta in the Poynting picture. It allows us to construct a comprehensive classification of all known optical angular momenta based on their key parameters and main physical properties.
NASA Astrophysics Data System (ADS)
Hardi, J. S.; Oschwald, M.
2016-07-01
The intact length of the dense oxygen core from an oxygen-hydrogen shear coaxial rocket injector was measured. The measurements were made in a rectangular rocket combustor with optical access and acoustic forcing. The combustor was operated at chamber pressures of 40 and 60 bar, with either ambient temperature or cryogenic hydrogen. The multielement injection spray is subjected to forced transverse gas oscillations of two different acoustic resonance modes; the first transverse (1T) mode at 4200 Hz and the first combined longitudinal-transverse (1L1T) at 5500 Hz. Intact core length is measured from high-speed shadowgraph imaging. The dependence of intact core length with increasing acoustic amplitude is compared for the two modes of excitation.
Nucleon Spin Structure: Longitudinal and Transverse
Jian-Ping Chen
2011-02-01
Inclusive Deep-Inelastic Scattering (DIS) experiments have provided us with the most extensive information on the unpolarized and longitudinal polarized parton (quark and gluon) distributions in the nucleon. It has becoming clear that transverse spin and transverse momentum dependent distributions (TMDs) study are crucial for a more complete understanding of the nucleon structure and the dynamics of the strong interaction. The transverse spin structure and the TMDs are the subject of increasingly intense theoretical and experimental study recently. With a high luminosity electron beam facility, JLab has played a major role in the worldwide effort to study both the longitudinal and transverse spin structure. Highlights of recent results will be presented. With 12-GeV energy upgrade, JLab will provide the most precise measurements in the valence quark region to close a chapter in longitudinal spin study. JLab will also perform a multi-dimensional mapping of the transverse spin structure and TMDs in the valence quark region through Semi-Inclusive DIS (SIDIS) experiments, providing a 3-d partonic picture of the nucleon in momentum space and extracting the u and d quark tensor charges of the nucleon. The precision mapping of TMDs will also allow a detailed study of the quark orbital motion and its dynamics.
Transverse Ising model with multi-impurity
NASA Astrophysics Data System (ADS)
Huang, Xuchu; Yang, Zhihua
2015-05-01
We study the transverse Ising spin model with spin-1 impurities under the exact solution. We develop a universal method to deal with the multi-impurity problem by introducing a displacement quantity in the wave function and get a recursive formula to simplify the calculation of the partition function. This allows us to rigorously determine the impurity effects for a specific distribution of impurity in the thermodynamic limit. The low temperature behaviors are governed by the interplay between host and impurity excitations, and the quantum critical fluctuations around the critical point of the transverse Ising model are tuned by the transverse field and the concentration of impurity. However the impurity effects are limited, which depends on the host-impurity exchange interaction and the coupling strength of impurities.
Efficient modeling in transversely isotropic inhomogeneous media
Alkhalifah, T.
1993-11-01
An efficient modeling technique for transversely isotropic, inhomogeneous media, is developed using a mix of analytical equations and numerical calculations. The analytic equation for the raypath in a factorized transversely isotropic (FTI) media with linear velocity variation, derived by Shearer and Chapman, is used to trace between two points. In addition, I derive an analytical equation for geometrical spreading in FTI media that aids in preserving program efficiency; however, the traveltime is calculated numerically. I then generalize the method to treat general transversely isotropic (TI) media that are not factorized anisotropic inhomogeneous by perturbing the FTI traveltimes, following the perturbation ideas of Cerveny and Filho. A Kirchhoff-summation-based program relying on Trorey`s (1970) diffraction method is used to generate synthetic seismograms for such a medium. For the type of velocity models treated, the program is much more efficient than finite-difference and general ray-trace modeling techniques.
Evolution of transverse modes in FELIX macropulses
Weits, H.H.; Lin, L.; Werkhoven, G.H.C. van
1995-12-31
We present ringdown measurements of both the intracavity beam, using a low reflection beamsplitter, as well as the hole-outcoupled beam of FELIX, the intracavity measurements being taken at various sets of transverse coordinates. Recent measurements show a significant difference in the decay of the signals at different radial positions, suggesting the presence of higher order transverse modes. The formation of transverse modes depends on the properties of the cold cavity and its losses (i.e. resonator parameters, diffraction and outcoupling at the hole, absorption and edge losses on the mirrors, waveguide clipping), as well as on the gain mechanism. Both simulations with the axisymmetric ELIXER code and previous hole-outcoupled measurements indicated a substantial energy content of the 2nd or 4th Gauss-Laguerre (GL) mode for the 20-30 {mu}m regime of FELIX. Moreover, as FELIX has a phase degenerate cavity, the fundamental and higher order transverse modes can interplay to create a reduced outcoupling efficiency at the hole. For example, in contrast to the decay rate of 13% per roundtrip that we would expect for a pure gaussian beam when we include a loss of 6% for the reflection at the intracavity beamsplitter, recent simulations indicate a decay rate as high as 23% of the hole-outcoupled signal. In this case the 2nd order GL mode contains 30% of the total intracavity power. The effect of transverse modes on subpulses in the limit cycle regime is an interesting aspect. As soon as a subpulse is losing contact with the electrons, its transverse pattern will exhibit an on-axis hole after a few roundtrips, according to the simulations. This process could mean that the subpulses are less pronounced in the hole-outcoupled signal of FELIX 1.
Transverse dune trailing ridges and vegetation succession
NASA Astrophysics Data System (ADS)
Hesp, Patrick A.; ‘Marisa' Martinez, M. L.
2008-07-01
We describe the evolution of, and vegetation succession on, a previously undescribed landform: transverse dune trailing ridges at El Farallón transgressive dunefield in the state of Veracruz, Mexico. Three-dimensional clinometer/compass and tape topographic surveys were conducted in conjunction with 1 m 2 contiguous percent cover and presence/absence vegetation survey transects at eight locations across two adjacent trailing ridges. At the study site, and elsewhere, the transverse dune trailing ridges are formed by vegetation colonization of the lateral margins of active transverse, barchanoidal transverse, and aklé or network dunes. For simplicity, all trailing ridges formed from these dune types are referred to as transverse dune trailing ridges. Because there are several transverse dunes in the dunefield, multiple trailing ridges can be formed at one time. Two adjacent trailing ridges were examined. The shortest length ridge was 70 m long, and evolving from a 2.5 m-high transverse dune, while the longer ridge was 140 m long, and evolving from an 8 m-high dune. Trailing ridge length is a proxy measure of ridge age, since the longer the ridge, the greater the length of time since initial formation. With increasing age or distance upwind, species diversity increased, as well as species horizontal extent and percent cover. In turn, the degree of bare sand decreased. Overall, the data indicate a successional trend in the vegetation presence and cover with increasing age upwind. Those species most tolerant to burial ( Croton and Palafoxia) begin the process of trailing ridge formation. Ipomoea and Canavalia are less tolerant to burial and also are typically the next colonizing species. Trachypogon does not tolerate sand burial or deposition very well and only appears after significant stabilization has taken place. The ridges display a moderately defined successional sequence in plant colonization and percentage cover with time (and upwind distance). They are
Surface transverse waves: properties, devices, and analysis.
Strashilov, Vesseline L; Yantchev, Ventsislav M
2005-05-01
Surface transverse waves represent a new generation of the surface acoustic wave (SAW) family that offers advantageous properties without further demand for new materials or improved design and technology. The most effective activity in the surface transverse wave (STW) area has been realized during the last decade with high-performance devices achieved and analytical methods developed. The present paper reviews the basic achievements in historical and factual order. A state-of-the-art introduction is combined with discussion on the development tendencies with specific emphasis on sensor technology.
Injection coupling with high amplitude transverse modes: Experimentation and simulation
NASA Astrophysics Data System (ADS)
Mery, Yoann; Ducruix, Sébastien; Scouflaire, Philippe; Candel, Sébastien
2009-06-01
High frequency combustion instabilities have technical importance in the design of liquid rocket engines. These phenomena involve a strong coupling between transverse acoustic modes and combustion. They are currently being investigated by combining experimentation and numerical simulations. On the experimental level, the coupling is examined in a model scale system featuring a multiple injector combustor (MIC) comprising five coaxial injectors fed with liquid oxygen and gaseous methane. This system is equipped with a novel VHAM actuator (Very High Amplitude Modulator) which comprises two nozzles and a rotating toothed wheel blocking the nozzles in an alternate fashion. This device was designed to obtain the highest possible levels of transverse oscillation in the MIC. After a brief review of the VHAM, this article reports cold flow experiments using this modulator. Velocity maps obtained under resonant conditions using the VHAM are examined at different instants during a cycle of oscillation. Experimental data are compared with numerical pressure and velocity fields obtained from an acoustic solver. The good agreement observed in the nozzle vicinity indicates that numerical simulations can be used to analyze the complex flow field generated by the VHAM. To cite this article: Y. Mery et al., C. R. Mecanique 337 (2009).
Fluctuating Hydrodynamics Confronts the Rapidity Dependence of Transverse Momentum Fluctuations
NASA Astrophysics Data System (ADS)
Pokharel, Rajendra; Gavin, Sean; Moschelli, George
2012-10-01
Interest in the development of the theory of fluctuating hydrodynamics is growing [1]. Early efforts suggested that viscous diffusion broadens the rapidity dependence of transverse momentum correlations [2]. That work stimulated an experimental analysis by STAR [3]. We attack this new data along two fronts. First, we compute STAR's fluctuation observable using the NeXSPheRIO code, which combines fluctuating initial conditions from a string fragmentation model with deterministic viscosity-free hydrodynamic evolution. We find that NeXSPheRIO produces a longitudinal narrowing, in contrast to the data. Second, we study the hydrodynamic evolution using second order causal viscous hydrodynamics including Langevin noise. We obtain a deterministic evolution equation for the transverse momentum density correlation function. We use the latest theoretical equations of state and transport coefficients to compute STAR's observable. The results are in excellent accord with the measured broadening. In addition, we predict features of the distribution that can distinguish 2nd and 1st order diffusion. [4pt] [1] J. Kapusta, B. Mueller, M. Stephanov, arXiv:1112.6405 [nucl-th].[0pt] [2] S. Gavin and M. Abdel-Aziz, Phys. Rev. Lett. 97, 162302 (2006)[0pt] [3] H. Agakishiev et al., STAR, STAR, Phys. Lett. B704
Thomas, R Z; Ruben, J L; de Vries, J; ten Bosch, J J; Huysmans, M C D N J M
2006-01-01
This paper describes a microradiographic method for measuring mineral concentration in a transversal geometry with thick (< or =3.2 mm) sections: transversal wavelength-independent microradiography (T-WIM). It was tested on bovine enamel and dentin samples in vitro, and the results were validated with those of transversal microradiography (TMR). 48 enamel and 48 dentin samples (3.2 x 3.2 x 1.5 mm) were embedded in acrylic resin, randomly divided into six groups of 8 dentin or 8 enamel samples, and demineralized for 0 (sound control), 1, 2, 3, 4, or 5 weeks. For T-WIM, samples were imaged on film with polychromatic 40-kV Cu X-rays with an Al (0.25 mm)/Ni (0.02 mm) filter together with an aluminium/zinc step wedge. TMR slices (about 80 mum for enamel and about 130 mum for dentine) were subsequently cut from the centre of the samples and subjected to TMR. Microradiographs from both methods were digitized and image analysis software was used to calculate lesion depth and mineral loss. The relations between T-WIM and TMR results for mineral loss (DeltaZ) and lesion depth were nearly linear (r > or = 0.96) for both enamel and dentin. The slopes of the regression lines were between 0.99 and 1.02 except for DeltaZ in dentine, which was 0.89. It was concluded that T-WIM is a suitable method for TMR on thick samples. PMID:16741358
Mitigating chromatic effects for the transverse focusing of intense charged particle beams
NASA Astrophysics Data System (ADS)
Mitrani, James; Kaganovich, Igor; Davidson, Ronald
2013-09-01
A final focusing scheme designed to minimize chromatic effects is discussed. Solenoids are often used for transverse focusing in accelerator systems that require a charged particle beam with a small focal spot and/or large energy density A sufficiently large spread in axial momentum will reduce the effectiveness of transverse focusing, and result in chromatic effects on the final focal spot. Placing a weaker solenoid upstream of a stronger final focusing solenoid (FFS) mitigates chromatic effects on transverse beam focusing. J.M. Mitrani et al., Nucl. Inst. Meth. Phys. Res. A (2013) http://dx.doi.org/10.1016/j.nima.2013.05.09 This work was supported by DOE contract DE-AC02-09CH11466.
A new fifth parameter for transverse isotropy II: partial derivatives
NASA Astrophysics Data System (ADS)
Kawakatsu, Hitoshi
2016-07-01
Kawakatsu et al. and Kawakatsu introduced a new fifth parameter, ηκ, to describe transverse isotropy (TI). Considering that ηκ characterizes the incidence angle dependence of body wave phase velocities for TI models, its relevance for body wave seismology is obvious. Here, we derive expressions for partial derivatives (sensitivity kernels) of surface wave phase velocity and normal mode eigenfrequency for the new set of five parameters. The partial derivative for ηκ is about twice as large as that for the conventional η, indicating that ηκ should be more readily resolved. While partial derivatives for S velocities are not so changed, those for P velocities are significantly modified; the sensitivity for anisotropic P velocities is greatly reduced. In contrary to the suggestion by Dziewonski & Anderson and Anderson & Dziewonski, there is not much control on the anisotropic P velocities. On the other hand, the significance of ηκ for long-period seismology has become clear.
Transverse instability digital damper for the Recycler
Balbekov, V.; /Fermilab
2006-02-01
Transverse beam instability of a coasting beam with a digital damper is examined. Threshold of instability is calculated in specific cases with Landau damping taken into account. The results are applied to the Fermilab Recycler Ring. Some improvement of existing RR damper is proposed.
Variation of transverse momentum in hadronic collisions
NASA Technical Reports Server (NTRS)
Saint Amand, J.; Uritam, R. A.
1975-01-01
The paper presents a detailed parameterization of the transverse momentum in hadronic collisions on multiplicity and on beam momentum. Hadronic collisions are considered at energies below the ultra-high energy domain, on the basis of an uncertainty relation and a naive eikonal model with an impact-parameter-dependent multiplicity.
Transversal filter for parabolic phase equalization
NASA Technical Reports Server (NTRS)
Kelly, Larry R. (Inventor); Waugh, Geoffrey S. (Inventor)
1993-01-01
An equalizer (10) for removing parabolic phase distortion from an analog signal (3), utilizing a pair of series connected transversal filters. The parabolic phase distortion is cancelled by generating an inverse parabolic approximation using a sinusoidal phase control filter (18). The signal (3) is then passed through an amplitude control filter (21) to remove magnitude ripple components.
Transverse ligament of the knee in humans.
Ratajczak, Wojciech; Jakubowicz, Marian; Pytel, Andrzej
2003-01-01
The purpose of this study was to trace the histological structure of the transverse ligament of the knee and its relation to the inferior lateral genicular artery. Investigations were carried out on 20 lower limbs (10 males, and 10 females) from the Department of Anatomy. It was found that close to the attachment of the transverse ligament to the menisci, bundles of fibres pass in vertical, oblique and horizontal directions, occupying a wide area on the anterior margin of the menisci. These fibres intermingle with bundles of the fibrocartilage of the menisci. In the area of the lateral attachment the inferior lateral genicular artery passes anteriorly to the transverse ligament, giving off numerous branches to the ligament. The medial part of the transverse ligament presents a thick rounded structure, surrounded by loose connective tissue. The fibres are arranged irregularly in bundles running horizontally on a tortuous course and with single spindle-like cells with darkly stained nuclei. The cells are not found at the ends of the ligament. Numerous blood vessels are observed between the bundles of fibres and on the periphery of the ligament.
Transverse stability in a Stark decelerator
Meerakker, Sebastiaan Y. T. van de; Bethlem, Hendrick L.; Vanhaecke, Nicolas; Meijer, Gerard
2006-02-15
The concept of phase stability in a Stark decelerator ensures that polar molecules can be accelerated, guided, or decelerated without loss; molecules within a certain position and velocity interval are kept together throughout the deceleration process. In this paper the influence of the transverse motion on phase stability in a Stark decelerator is investigated. For typical deceleration experiments--i.e., for high values of the phase angle {phi}{sub 0}--the transverse motion considerably enhances the region in phase space for which phase stable deceleration occurs. For low values of {phi}{sub 0}, however, the transverse motion reduces the acceptance of a Stark decelerator and unstable regions in phase space appear. These effects are quantitatively explained in terms of a coupling between the longitudinal and transverse motion. The predicted longitudinal acceptance of a Stark decelerator is verified by measurements on a beam of OH (X {sup 2}{pi}{sub 3/2},J=3/2) radicals passing through a Stark decelerator.
Maximum Possible Transverse Velocity in Special Relativity.
ERIC Educational Resources Information Center
Medhekar, Sarang
1991-01-01
Using a physical picture, an expression for the maximum possible transverse velocity and orientation required for that by a linear emitter in special theory of relativity has been derived. A differential calculus method is also used to derive the expression. (Author/KR)
Measuring transverse shape with virtual photons
Hoyer, Paul; Kurki, Samu
2011-06-01
A two-dimensional Fourier transform of hadron form factors allows to determine their charge density in transverse space. We show that this method can be applied to any virtual photon induced transition, such as {gamma}{sup *}(q)+N{yields}{pi}N. Only Fock states that are common to the initial and final states contribute to the amplitudes, which are determined by the overlap of the corresponding light-front wave functions. Their transverse extent may be studied as a function of the final state configuration, allowing qualitatively new insight into strong interaction dynamics. Fourier transforming the cross section (rather than the amplitude) gives the distribution of the transverse distance between the virtual photon interaction vertices in the scattering amplitude and its complex conjugate. While the measurement of parton distributions in longitudinal momentum depends on the leading twist approximation (-q{sup 2}{yields}{infinity} limit), all q{sup 2}<0 values contribute to the Fourier transform, with the transverse resolution increasing with the available range in q{sup 2}. We illustrate the method using QED amplitudes.
Sex Education as a Transversal Subject
ERIC Educational Resources Information Center
Rabelo, Amanda Oliveira; Pereira, Graziela Raupp; Reis, Maria Amélia; Ferreira, António G.
2015-01-01
Currently, sex education is in many countries a transversal subject, in which the school becomes a privileged place for the implementation of policies that aim at promoting "public health." Its design as a cross-cutting subject envisages fostering the dissemination of these subjects in all pedagogical and curricular fields; however, we…
Resources - ALS ... The following organizations are good resources for information on amyotrophic lateral sclerosis : Muscular Dystrophy Association -- mda.org/disease/amyotrophic-lateral-sclerosis National Amyotrophic Lateral Sclerosis (ALS) Registry -- ...
NASA Astrophysics Data System (ADS)
Bliokh, Konstantin Y.
2016-03-01
We provide an overview of recent theoretical and experimental studies, which revisited the basic dynamical properties of light: momentum and angular momentum. Recently, we described qualitatively new types of the spin and momentum in structured optical fields. These are: (i) the transverse spin, which is orthogonal to the wave vector and is independent of the helicity, and (ii) the anomalous transverse momentum, which depends on the helicity of light. Both of these quantities were described and measured experimentally in various optical systems, and they are currently attracting rapidly growing attention. In particular, the transverse spin in evanescent waves has found promising applications for robust spin-controlled unidirectional coupling to surface and waveguide optical modes. In turn, the transverse momentum provides a weak spin-dependent optical force, which is orthogonal to both the propagation direction and the intensity gradient in a wave field.
Transversity and Transverse-Momentum Distribution Measurements from Phenix and Brahms
NASA Astrophysics Data System (ADS)
Aidala, C.
2009-04-01
A variety of measurements performed utilizing transversely polarized proton-proton collisions at the Relativistic Heavy Ion Collider (RHIC) are now available. Recent results from the PHENIX and BRAHMS experiments are presented and discussed.
MEASUREMENT OF TRANSVERSE ECHOES IN RHIC.
FISCHER, W.; SATOGATA, T.; TOMAS. R.
2005-05-16
Beam echoes are a very sensitive method to measure diffusion, and longitudinal echo measurements were performed in a number of machines. In RHIC, for the first time, a transverse beam echo was observed after applying a dipole kick followed by a quadrupole .kick. After application of the dipole kick, the dipole moment decohered completely due to lattice nonlinearities. When a quadrupole kick is applied at time {tau} after the dipole kick, the beam re-cohered at time 2{tau} thus showing an echo response. We describe the experimental setup and measurement results. In the measurements the dipole and quadrupole kick amplitudes, amplitude dependent tune shift, and the time between dipole and quadrupole kick were varied. In addition, measurements were taken with gold bunches of different intensities. These should exhibit different transverse diffusion rates due to intra-beam scattering.
BEAM TRANSVERSE ISSUES AT THE SNS LINAC
Zhang, Yan; Allen, Christopher K; Holmes, Jeffrey A; Galambos, John D; Wang, Jian-Guang
2010-01-01
The Spallation Neutron Source (SNS) linac system is designed to deliver 1 GeV pulsed H- beams up to 1.56 MW. As beam power was increased from 10 kW to 680 kW in less than three years, beam loss in the accelerator systems C particularly in the superconducting linac (SCL), became more critical. In the previous studies, beam loss in the SCL was mainly attributed to longitudinal problems. However, our most recent simulations have focused on the transverse issues. These include multipole components from magnet imperfections and from dipole corrector windings of the SNS linac quadrupoles. The effects of these multipoles coupled with other transverse errors and a new possible cause of beam loss will be discussed.
Damped transverse oscillations of interacting coronal loops
NASA Astrophysics Data System (ADS)
Soler, Roberto; Luna, Manuel
2015-10-01
Damped transverse oscillations of magnetic loops are routinely observed in the solar corona. This phenomenon is interpreted as standing kink magnetohydrodynamic waves, which are damped by resonant absorption owing to plasma inhomogeneity across the magnetic field. The periods and damping times of these oscillations can be used to probe the physical conditions of the coronal medium. Some observations suggest that interaction between neighboring oscillating loops in an active region may be important and can modify the properties of the oscillations. Here we theoretically investigate resonantly damped transverse oscillations of interacting nonuniform coronal loops. We provide a semi-analytic method, based on the T-matrix theory of scattering, to compute the frequencies and damping rates of collective oscillations of an arbitrary configuration of parallel cylindrical loops. The effect of resonant damping is included in the T-matrix scheme in the thin boundary approximation. Analytic and numerical results in the specific case of two interacting loops are given as an application.
[The transversality and health promotion schools].
Gavidia Catalán, V
2001-01-01
The following article shows the evolution of the schools contribution to the Health Education of children and young people. Moving on from the traditional concept of health, today, Health Education has a general and global meaning, which encompasses all of the physical, psychological and social aspects of health. These aspects define the characteristics of the "Healthy School". The need to broach the "transversal subject" offers schools the possibility of developing "transversality" in the Health Education. Finally, the concept of promoting health defines, together with the other subjects, that which we understand by "the heath promotion schools", which attempts to progress the full integration of schools in the society in which they are located. PMID:11833260
Transverse ranges and neotectonics of southern California
Hill, M.L.
1990-01-01
The Transverse Ranges and the east-trending folds and reverse faults that elevate them began forming in mid-Pleistocene time by regional north-south crustal shortening. The adjacent Mojave Desert and Basin and Range provinces continue to respond to this regional strain by east-west crustal extension. Before {approximately}5 Ma the regional structure was characterized by conjugate northwest-trending right-slip faults (San Andreas set) and northeast-trending left-slip faults (Garlock set). Thereafter, the San Andreas set of faults became simple shears separating the North American and Pacific plates. With the mid-Pleistocene inception of the Transverse Ranges, the San Andreas fault deviated from its N40{degree} - 45{degree}W trend in short N75{degree}W-trending segments on the north and south sides of these mountains in response to the new, and local, strain system of upward crustal extension.
Transversal Clifford gates on folded surface codes
NASA Astrophysics Data System (ADS)
Moussa, Jonathan E.
2016-10-01
Surface and color codes are two forms of topological quantum error correction in two spatial dimensions with complementary properties. Surface codes have lower-depth error detection circuits and well-developed decoders to interpret and correct errors, while color codes have transversal Clifford gates and better code efficiency in the number of physical qubits needed to achieve a given code distance. A formal equivalence exists between color codes and folded surface codes, but it does not guarantee the transferability of any of these favorable properties. However, the equivalence does imply the existence of constant-depth circuit implementations of logical Clifford gates on folded surface codes. We achieve and improve this result by constructing two families of folded surface codes with transversal Clifford gates. This construction is presented generally for qudits of any dimension. The specific application of these codes to universal quantum computation based on qubit fusion is also discussed.
[Acute transverse myelitis in a traveler].
García Allende, Natalia; García Posada, Mara J; Radosta, Mariana F; Sánchez, Ana V; Mayer Wolf, Micaela; Rodríguez, Viviana
2016-01-01
Acute transverse myelitis is defined as an acquired neuroimmune disorder of the spinal cord, which occurs as a consequence of a primary event, or directly related to an autoimmune inflammatory disease, an infectious or post-infectious disease. Amongst infectious etiologies, Borrelia spp., a tick-bourne anthropozoonosis of the ixodidae family, prevails. Approximately 10 to 15% of patients with Lyme disease undergo neurologic manifestations, with an assorted and uncertain array of clinical syndromes. Transverse myelitis accounts for up to 5% of Lyme neuroborreliosis. We describe the case of a traveler from endemic zone for Lyme disease, with encephalomyelitis secondary to acute infection by Borrelia burgderfori, with complete resolution of symptoms after concluding adequate antibiotic treatment. PMID:27576284
Characteristics of transverse waves in chromospheric mottles
Kuridze, D.; Mathioudakis, M.; Jess, D. B.; Keenan, F. P.; Verth, G.; Erdélyi, R.; Morton, R. J.; Christian, D. J.
2013-12-10
Using data obtained by the high temporal and spatial resolution Rapid Oscillations in the Solar Atmosphere instrument on the Dunn Solar Telescope, we investigate at an unprecedented level of detail transverse oscillations in chromospheric fine structures near the solar disk center. The oscillations are interpreted in terms of propagating and standing magnetohydrodynamic kink waves. Wave characteristics including the maximum transverse velocity amplitude and the phase speed are measured as a function of distance along the structure's length. Solar magnetoseismology is applied to these measured parameters to obtain diagnostic information on key plasma parameters (e.g., magnetic field, density, temperature, flow speed) of these localized waveguides. The magnetic field strength of the mottle along the ∼2 Mm length is found to decrease by a factor of 12, while the local plasma density scale height is ∼280 ± 80 km.
Single transverse-spin asymmetry in QCD
NASA Astrophysics Data System (ADS)
Koike, Yuji
2014-09-01
So far large single transverse-spin asymmetries (SSA) have been observed in many high-energy processes such as semi-inclusive deep inelastic scattering and proton-proton collisions. Since the conventional parton model and perturbative QCD can not accomodate such large SSAs, the framework for QCD hard processes had to be extended to understand the mechanism of SSA. In this extended frameworks of QCD, intrinsic transverse momentum of partons and the multi-parton (quark-gluon and pure-gluonic) correlations in the hadrons, which were absent in the conventional framework, play a crucial role to cause SSAs, and well-defined formulation of these effects has been a big challenge for QCD theorists. Study on these effects has greatly promoted our understanding on QCD dynamics and hadron structure. In this talk, I will present an overview on these theoretical activity, emphasizing the important role of the Drell-Yan process.
Transverse Instabilities in the Fermilab Recycler
Prost, L.R.; Burov, A.; Shemyakin, A.; Bhat, C.M.; Crisp, J.; Eddy, N.; /Fermilab
2011-07-01
Transverse instabilities of the antiproton beam have been observed in the Recycler ring soon after its commissioning. After installation of transverse dampers, the threshold for the instability limit increased significantly but the instability is still found to limit the brightness of the antiprotons extracted from the Recycler for Tevatron shots. In this paper, we describe observations of the instabilities during the extraction process as well as during dedicated studies. The measured instability threshold phase density agrees with the prediction of the rigid beam model within a factor of 2. Also, we conclude that the instability threshold can be significantly lowered for a bunch contained in a narrow and shallow potential well due to effective exclusion of the longitudinal tails from Landau damping.
Transversity studies with protons and light nuclei
NASA Astrophysics Data System (ADS)
Scopetta, Sergio
2011-12-01
A general formalism to evaluate time-reversal odd transverse momentum dependent parton distributions (T-odd TMDS) is reviewed and applied to the calculation of the leading-twist quantities, i.e., the Sivers and the Boer-Mulders functions. Two different models of the proton structure, namely a non relativistic constituent quark model and the MIT bag model, have been used. The results obtained in both frameworks fulfill the Burkardt sum rule to a large extent. The calculation of nuclear effects in the extraction of neutron single spin asymmetries in semi-inclusive deep inelastic scattering off transversely polarized 3He is also illustrated. In the kinematics of JLab, it is found that the nuclear effects described by an Impulse Approximation approach are under theoretical control.
Transverse acousto-electric effect in superconductors
NASA Astrophysics Data System (ADS)
Lipavský, P.; Koláček, J.; Lin, P.-J.
2016-06-01
We formulate a theory based on the time-dependent Ginzburg-Landau (TDGL) theory and Newtonian vortex dynamics to study the transverse acousto-electric response of a type-II superconductor with Abrikosov vortex lattice. When exposed to a transverse acoustic wave, Cooper pairs emerge from the moving atomic lattice and moving electrons. As in the Tolman-Stewart effect in a normal metal, an electromagnetic field is radiated from the superconductor. We adapt the equilibrium-based TDGL theory to this non-equilibrium system by using a floating condensation kernel. Due to the interaction between normal and superconducting components, the radiated electric field as a function of magnetic field attains a maximum value occurring below the upper critical magnetic field. This local increase in electric field has weak temperature dependence and is suppressed by the presence of impurities in the superconductor.
Complementary methods of transverse emittance measurement
Zagel, James; Hu, Martin; Jansson, Andreas; Thurman-Keup, Randy; Yan, Ming-Jen; /Fermilab
2008-05-01
Several complementary transverse emittance monitors have been developed and used at the Fermilab accelerator complex. These include Ionization profile Monitors (IPM), Flying Wires, Schottky detectors and a Synchrotron Light Monitor (Synchlite). Mechanical scrapers have also been used for calibration purposes. This paper describes the various measurement devices by examining their basic features, calibration requirements, systematic uncertainties, and applications to collider operation. A comparison of results from different kinds of measurements is also presented.
Ferrimagnetic behaviors in a transverse Ising nanoisland
NASA Astrophysics Data System (ADS)
Kaneyoshi, T.
2016-05-01
In this paper, the phase diagrams and magnetizations of a magnetic nanoisland described by the transverse Ising model (TIM) are investigated by the use of the effective-field theory (EFT) with correlations. A lot of characteristic behaviors observed in standard ferrimagnetic materials as well as novel phenomena have been obtained, although the system consists of two finite spin-1/2 layers coupled antiferromagnetically with a negative interlayer coupling.
Observations of the PSR transverse instability
Colton, E. ); Fitzgerald, D.; Hardek, T.; Macek, R.J.; Plum, M.A.; Thiessen, H.A.; Wang, T.S. ); Neuffer, D. )
1991-01-01
A fast instability with beam loss is observed in the Los Alamos Proton Storage Ring (PSR) when the injected beam current exceeds thresholds, with both bunched and unbunched beams. Large coherent transverse oscillations occur before and during beam loss. Recent observations of the instability indicate that it is an e-p''-type instability, driven by coupled oscillations due to electrons trapped within the proton beam. 5 refs., 3 figs.
TRANSVERSE IMPEDANCE MEASUREMENT AT THE RHIC.
ZHANG,S.Y.; HUANG,H.; CAMERON,P.; DREES,A.; FLILLER,R.; SATOGATA,T.
2002-06-02
The RHIC transverse impedance was measured during the last operation run. Measurement of the imaginary part of the broadband impedance was the main goal. No large difference between the two rings was found nor in either plane. The measured tune shift is larger than the expected by a factor of 2.5 to 3. Several other issues such as the real part impedance measurement are also presented.
Transverse Stress Fracture of the Proximal Patella
Atsumi, Satoru; Arai, Yuji; Kato, Ko; Nishimura, Akinobu; Nakazora, Shigeto; Nakagawa, Shuji; Ikoma, Kazuya; Fujiwara, Hiroyoshi; Sudo, Akihiro; Kubo, Toshikazu
2016-01-01
Abstract Among stress fractures associated with sports activities, patellar stress fracture is rare. Regarding patella stress fractures, so far only distal transverse or lateral longitudinal fractures have been reported, but there are no reports of transverse fractures occurring in the proximal patella. We describe an extremely rare case of transverse stress fracture of proximal patella in a 9-year-old athlete. A 9-year old boy, who participated in sports (sprints and Kendo) presented with left knee pain without any external injury. In plain radiographs, a fracture line was observed in the proximal 1/3 of the left patella, and a patella stress fracture was diagnosed. For treatment, because 7 months of conservative therapy showed no improvement, internal fixation was carried out using Acutrak screws, and bone union was thus achieved. Three months after the operation, he was able to return to his previous level of athletic sports activity. Regarding the mechanism of onset, it is believed that the causes are longitudinal traction force and patellofemoral contact pressure. On the other hand, the contact region of the patella with the femur changes with the flexion angle of the knee. In the current case, the fracture occurred at a site where the patella was in contact with the femur at a flexion angle of >90°, so it is believed that it occurred as a clinical condition from being subjected to repeated longitudinal traction force and patellofemoral contact pressure at a flexion angle of >90°, during the sports activities of sprints and Kendo. The nonunion of the transverse stress fracture of his proximal patella was successfully treated with internal fixation using Acutrak screws. PMID:26871789
Broadband transverse electric surface wave in silicene
NASA Astrophysics Data System (ADS)
Ukhtary, M. Shoufie; Nugraha, Ahmad R. T.; Hasdeo, Eddwi H.; Saito, Riichiro
2016-08-01
Transverse electric (TE) surface wave in silicine is theoretically investigated. The TE surface wave in silicene is found to exhibit better characteristics compared with that in graphene, in terms of a broader frequency range and more confinement to the surface which originate from the buckled structure of silicene. We found that even undoped silicene can support the TE surface wave. We expect the similar characteristics of the TE surface wave in other two-dimensional materials that have a slightly buckled honeycomb lattice.
Extraction of Transversity and Collins Functions
Anselmino, Mauro; Boglione, Mariaelena; D'Alesio, Umberto; Melis, Stefano; Murgia, Francesco; Prokudin, Alexei
2014-01-01
We present a global re-analysis of recent experimental data on azimuthal asymmetries in semi-inclusive deep inelastic scattering, from the HERMES and COMPASS Collaborations, and in e{sup +}e{sup -} --> h_1h_2X processes, from the Belle Collaboration. The transversity distribution and the Collins functions are extracted simultaneously, in a revised analysis which also takes into account a new parameterization of the unknown functions.
Transverse Momentum Dependent Hadron Multiplicities at COMPASS
NASA Astrophysics Data System (ADS)
Makke, Nour
2016-02-01
Unpolarised semi-inclusive deep inelastic scattering is receiving a growing interest as a powerful tool to access poorly known transverse momentum dependent parton distributions and fragmentation functions that play a key role in many processes, in particular in the study of the spin structure of the nucleon. These functions can be investigated through experimental observables. New results on these observables by the COMPASS experiment at CERN will be shown and discussed.
Transverse-momentum-dependent parton distributions (TMDs)
NASA Astrophysics Data System (ADS)
Bacchetta, Alessandro
2011-10-01
Transverse-momentum-dependent parton distributions (TMDs) provide three-dimensional images of the partonic structure of the nucleon in momentum space. We made impressive progress in understanding TMDs, both from the theoretical and experimental point of view. This brief overview on TMDs is divided in two parts: in the first, an essential list of achievements is presented. In the second, a selection of open questions is discussed.
Theoretical Overview on Recent Developments in Transverse Spin Physics
Yuan, Feng
2009-01-14
Transverse-spin physics has been very active and rapidly developing in the last few years. In this talk, I will briefly summarize recent theoretical developments, focusing on the associated QCD dynamics in transverse spin physics.
Viscoelasticity of Tendons Under Transverse Compression.
Paul Buckley, C; Samuel Salisbury, S T; Zavatsky, Amy B
2016-10-01
Tendons are highly anisotropic and also viscoelastic. For understanding and modeling their 3D deformation, information is needed on their viscoelastic response under off-axis loading. A study was made, therefore, of creep and recovery of bovine digital extensor tendons when subjected to transverse compressive stress of up to ca. 100 kPa. Preconditioned tendons were compression tested between glass plates at increasing creep loads. The creep response was anomalous: the relative rate of creep reduced with the increasing stress. Over each ca. 100 s creep period, the transverse creep deformation of each tendon obeyed a power law dependence on time, with the power law exponent falling from ca. 0.18 to an asymptote of ca. 0.058 with the increasing stress. A possible explanation is stress-driven dehydration, as suggested previously for the similar anomalous behavior of ligaments. Recovery after removal of each creep load was also anomalous. Relative residual strain reduced with the increasing creep stress, but this is explicable in terms of the reducing relative rate of creep. When allowance was made for some adhesion occurring naturally between tendon and the glass plates, the results for a given load were consistent with creep and recovery being related through the Boltzmann superposition principle (BSP). The tendon tissue acted as a pressure-sensitive adhesive (PSA) in contact with the glass plates: explicable in terms of the low transverse shear modulus of the tendons. PMID:27496279
Collins Fragmentation and the Single Transverse Spin Asymmetry
Yuan, Feng; Zhou, Jian
2009-03-26
We study the Collins mechanism for the single transverse spin asymmetry in the collinear factorization approach. The correspondent twist-three fragmentation function is identified. We show that the Collins function calculated in this approach is universal.We further examine its contribution to the single transverse spin asymmetry of semi-inclusive hadron production in deep inelastic scattering and demonstrate that the transverse momentum dependent and twist-three collinear approaches are consistent in the intermediate transverse momentum region where both apply.
Cladding for transverse-pumped solid-state laser
NASA Technical Reports Server (NTRS)
Byer, Robert L. (Inventor); Fan, Tso Y. (Inventor)
1989-01-01
In a transverse pumped, solid state laser, a nonabsorptive cladding surrounds a gain medium. A single tranverse mode, namely the Transverse Electromagnetic (TEM) sub 00 mode, is provided. The TEM sub 00 model has a cross sectional diameter greater than a transverse dimension of the gain medium but less than a transverse dimension of the cladding. The required size of the gain medium is minimized while a threshold for laser output is lowered.
Xodo, Serena; Saccone, Gabriele; Cromi, Antonella; Ozcan, Pinar; Spagnolo, Emanuela; Berghella, Vincenzo
2016-07-01
It is imperative to have evidence-based guidelines for cesarean delivery. The aim of this meta-analysis was to evaluate the effectiveness of a cephalad-caudad compared to transverse blunt expansion of the uterine incision to reduce blood loss in women who underwent low-segment transverse cesarean delivery. We therefore performed a systematic search in electronic databases from their inception until March 2016. We included all randomized trials comparing cephalad-caudad versus transverse (control group) blunt expansion of the uterine incision in women who underwent a low transverse cesarean delivery. The primary outcome was postpartum blood loss, defined as the mean amount of blood loss (mL). Two trials (921 women) were analyzed. After the transverse uterine incision in the lower uterine segment with the scalpel, the uterine incision was then bluntly expanded by the designated method. Blunt expansion of the primary incision was derived by placing the index fingers of the operating surgeon into the incision and pulling the fingers apart laterally (transverse group) or cephalad (cephalad-caudad group). Women who were randomized in the cephalad-caudad group had lower: mean of postpartum blood loss, hemoglobin drop and hematocrit drop 24h after cesarean, unintended extension, uterine vessels injury, blood loss >1500mL and need for additional stitches. There was no statistically significant difference in the incidence of blood loss >1000mL, in the operating time and in post-operative pain. In conclusion, expansion of the uterine incision with fingers in a cephalad-caudad direction is associated with better maternal outcomes and, therefore, should be preferred to transverse expansion during a cesarean delivery. PMID:27180273
Estimation of viscosity based on transverse momentum correlations
NASA Astrophysics Data System (ADS)
Sharma, Monika
2010-02-01
The heavy ion program at RHIC created a paradigm shift in the exploration of strongly interacting hot and dense matter. An important milestone achieved is the discovery of the formation of strongly interacting matter which seemingly flows like a perfect liquid at temperatures on the scale of T ˜ 2 x10^12 K [1]. As a next step, we consider measurements of transport coefficients such as kinematic, shear or bulk viscosity? Many calculations based on event anisotropy measurements indicate that the shear viscosity to the entropy density ratio (η/s) of the fluid formed at RHIC is significantly below that of all known fluids including the superfluid ^4He [2]. Precise determination of η/s ratio is currently a subject of extensive study. We present an alternative technique for the determination of medium viscosity proposed by Gavin and Aziz [3]. Preliminary results of measurements of the evolution of the transverse momentum correlation function with collision centrality of Au + Au interactions at √sNN = 200 GeV will be shown. We present results on differential version of the correlation measure and describe its use for the experimental determination of η/s.[4pt] [1] J. Adams et al., [STAR Collaboration], Nucl. Phys. A 757 (2005) 102.[0pt] [2] R. A. Lacey et al., Phys. Rev. Lett. 98 (2007) 092301.[0pt] [3] S. Gavin and M. Abdel-Aziz, Phys. Rev. Lett. 97 (2006) 162302. )
Physical modeling of transverse drainage mechanisms
NASA Astrophysics Data System (ADS)
Douglass, J. C.; Schmeeckle, M. W.
2005-12-01
Streams that incise across bedrock highlands such as anticlines, upwarps, cuestas, or horsts are termed transverse drainages. Their relevance today involves such diverse matters as highway and dam construction decisions, location of wildlife corridors, better-informed sediment budgets, and detailed studies into developmental histories of late Cenozoic landscapes. The transient conditions responsible for transverse drainage incision have been extensively studied on a case-by-case basis, and the dominate mechanisms proposed include: antecedence, superimposition, overflow, and piracy. Modeling efforts have been limited to antecedence, and such the specific erosional conditions required for transverse drainage incision, with respect to the individual mechanisms, remains poorly understood. In this study, fifteen experiments attempted to simulate the four mechanisms and constructed on a 9.15 m long, 2.1 m wide, and 0.45 m deep stream table. Experiments lasted between 50 and 220 minutes. The stream table was filled with seven tons of sediment consisting of a silt and clay (30%) and a fine to coarse sand (70%) mixture. The physical models highlighted the importance of downstream aggradation with regard to antecedent incision versus possible defeat and diversion. The overflow experiments indicate that retreating knickpoints across a basin outlet produce a high probability of downstream flooding when associated with a deep lake. Misters used in a couple of experiments illustrate a potential complication with regard to headward erosion driven piracy. Relatively level asymmetrically sloped ridges allow for the drainage divide across the ridge to retreat from headward erosion, but hindered when the ridge's apex undulates or when symmetrically sloped. Although these physical models cannot strictly simulate natural transverse drainages, the observed processes, their development over time, and resultant landforms roughly emulate their natural counterparts. Proposed originally from
Longitudinal and transverse mode evolution in free electron laser
Dattoli, G.; Giannessi, L.; Georgii, R.
1995-12-31
We use the method of Padg approximants and Fourier transform techniques to treat analytically the problem of transverse and longitudinal mode evolution in FELs. We obtain simple relations providing a transparent understanding of the dynamic of pulse propagation effects and of transverse mode guiding. We discuss the interplay with inhomogeneous broadening effects and derive gain formulae including longitudinal and transverse mode couplings.
Hogue, A S; Ravosa, M J
2001-09-01
Based on extensive experimental work on primates, two masticatory loading regimes have emerged as the likely determinants of mandibular symphyseal fusion-dorsoventral shear and lateral transverse bending (wishboning) (Ravosa and Hylander, 1994; Hylander et al., 1998, 2000). Recently, however, it has been argued that, rather than functioning to strengthen the symphysis during mastication, fusion serves to stiffen the symphyseal joint so as to facilitate increased transverse jaw movements during occlusion (Lieberman and Crompton, 2000). As part of this transverse stiffness model, it has been suggested that taxa with fused symphyses should also exhibit more horizontally oriented occlusal wear facets. Using a series of univariate and bivariate analyses, we test predictions of these three models in a sample of 44 species of selenodont artiodactyls. Consistent with the wishboning and transverse stiffness models, taxa with fused symphyses (camelids) have more horizontally oriented M(2) and M(2) occlusal wear facets, anteroposteriorly (AP) elongate symphyses, and relatively wider corpora. Contrary to the dorsoventral shear model, camelids do not have relatively deeper corpora (due to greater parasagittal bending). While taxa with ossified symphyses have relatively larger symphysis cross-sectional areas, this appears to be the byproduct of an increase in AP symphysis length due to greater lateral transverse bending of the mandible. Theoretical consideration of the biomechanics of mastication further suggests that strength, not stiffness, is the critical factor in determining symphyseal ossification. Thus, like anthropoid primates, fusion in selenodont artiodactyls appears to function in resisting increased wishboning stresses arising from an emphasis on transverse occlusal/mandibular movements and loads.
A Transversely Isotropic Thermo-mechanical Framework for Oil Shale
NASA Astrophysics Data System (ADS)
Semnani, S. J.; White, J. A.; Borja, R. I.
2014-12-01
The present study provides a thermo-mechanical framework for modeling the temperature dependent behavior of oil shale. As a result of heating, oil shale undergoes phase transformations, during which organic matter is converted to petroleum products, e.g. light oil, heavy oil, bitumen, and coke. The change in the constituents and microstructure of shale at high temperatures dramatically alters its mechanical behavior e.g. plastic deformations and strength, as demonstrated by triaxial tests conducted at multiple temperatures [1,2]. Accordingly, the present model formulates the effects of changes in the chemical constituents due to thermal loading. It is well known that due to the layered structure of shale its mechanical properties in the direction parallel to the bedding planes is significantly different from its properties in the perpendicular direction. Although isotropic models simplify the modeling process, they fail to accurately describe the mechanical behavior of these rocks. Therefore, many researchers have studied the anisotropic behavior of rocks, including shale [3]. The current study presents a framework to incorporate the effects of transverse isotropy within a thermo-mechanical formulation. The proposed constitutive model can be readily applied to existing finite element codes to predict the behavior of oil shale in applications such as in-situ retorting process and stability assessment in petroleum reservoirs. [1] Masri, M. et al."Experimental Study of the Thermomechanical Behavior of the Petroleum Reservoir." SPE Eastern Regional/AAPG Eastern Section Joint Meeting. Society of Petroleum Engineers, 2008. [2] Xu, B. et al. "Thermal impact on shale deformation/failure behaviors---laboratory studies." 45th US Rock Mechanics/Geomechanics Symposium. American Rock Mechanics Association, 2011. [3] Crook, AJL et al. "Development of an orthotropic 3D elastoplastic material model for shale." SPE/ISRM Rock Mechanics Conference. Society of Petroleum Engineers
Transversity GPD in photo- and electroproduction of two vectormesons
Enberg, Rikard; Pire, Bernard; Szymanowski, Lech
2006-01-17
The chiral-odd generalized parton distribution (GPD), or transversity GPD, of the nucleon can be accessed experimentally through the photo- or electroproduction of two vector mesons on a polarized nucleon target, {gamma}{sup (*)}N {yields} {rho}{sub 1}{rho}{sub 2}N', where {rho}{sub 1} is produced at large transverse momentum, {rho}{sub 2} is transversely polarized, and the mesons are separated by a large rapidity gap. We predict the cross section for this process for both transverse and longitudinal {rho}{sub 2} production. To this end we propose a model for the transversity GPDH{sub T}(x,{zeta},t), and give an estimate of the relative sizes of the transverse and longitudinal {rho}{sub 2}cross sections. We show that a dedicated experiment at high energy should be able to measure the transversity content of the proton.
Melamed, Timor; Abuhasira, Dor; Dayan, David
2012-06-01
The present contribution is concerned with applying beam-type expansion to a planar aperture time-dependent (TD) electromagnetic field in which the propagating elements, the electromagnetic pulsed-beams, are a priori decomposed into transverse electric (TE) and transverse magnetic (TM) field polarizations. The propagating field is described as a discrete superposition of tilted, shifted, and delayed TE and TM electromagnetic pulsed-beam propagators over the frame spectral lattice. These waveobjects are evaluated by using TD plane-wave spectral representations. Explicit asymptotic expressions for electromagnetic isodiffracting pulsed-quadratic beam propagators are presented, as well as a numerical example.
NASA Astrophysics Data System (ADS)
Averkov, Yu. O.; Yakovenko, V. M.; Yampol'skii, V. A.; Nori, Franco
2014-07-01
We predict the coexistence of both transverse-electric- and transverse-magnetic-polarized localized electromagnetic waves that can propagate in the same frequency range along a graphene layer inserted in a photonic crystal. In addition, we studied the excitation of these modes by an external wave and have shown that the resonance peaks of the sample transmissivity should be observed due to the excitation of the localized waves, independently of the polarization of the exciting wave. The simplicity of the derived dispersion relations for the localized modes and the possibility to excite waves of both polarizations provide a method for measuring graphene conductivity.
Interacting dark sector with transversal interaction
Chimento, Luis P.; Richarte, Martín G.
2015-03-26
We investigate the interacting dark sector composed of dark matter, dark energy, and dark radiation for a spatially flat Friedmann-Robertson-Walker (FRW) background by introducing a three-dimensional internal space spanned by the interaction vector Q and solve the source equation for a linear transversal interaction. Then, we explore a realistic model with dark matter coupled to a scalar field plus a decoupled radiation term, analyze the amount of dark energy in the radiation era and find that our model is consistent with the recent measurements of cosmic microwave background anisotropy coming from Planck along with the future constraints achievable by CMBPol experiment.
Transversely isotropic elasticity imaging of cancellous bone.
Shore, Spencer W; Barbone, Paul E; Oberai, Assad A; Morgan, Elise F
2011-06-01
To measure spatial variations in mechanical properties of biological materials, prior studies have typically performed mechanical tests on excised specimens of tissue. Less invasive measurements, however, are preferable in many applications, such as patient-specific modeling, disease diagnosis, and tracking of age- or damage-related degradation of mechanical properties. Elasticity imaging (elastography) is a nondestructive imaging method in which the distribution of elastic properties throughout a specimen can be reconstructed from measured strain or displacement fields. To date, most work in elasticity imaging has concerned incompressible, isotropic materials. This study presents an extension of elasticity imaging to three-dimensional, compressible, transversely isotropic materials. The formulation and solution of an inverse problem for an anisotropic tissue subjected to a combination of quasi-static loads is described, and an optimization and regularization strategy that indirectly obtains the solution to the inverse problem is presented. Several applications of transversely isotropic elasticity imaging to cancellous bone from the human vertebra are then considered. The feasibility of using isotropic elasticity imaging to obtain meaningful reconstructions of the distribution of material properties for vertebral cancellous bone from experiment is established. However, using simulation, it is shown that an isotropic reconstruction is not appropriate for anisotropic materials. It is further shown that the transversely isotropic method identifies a solution that predicts the measured displacements, reveals regions of low stiffness, and recovers all five elastic parameters with approximately 10% error. The recovery of a given elastic parameter is found to require the presence of its corresponding strain (e.g., a deformation that generates ɛ₁₂ is necessary to reconstruct C₁₂₁₂), and the application of regularization is shown to improve accuracy. Finally
Summary report on transverse emittance preservation
Chou, W.; Vos, L.
1997-12-01
During the past years, significant progress has been made in understanding the beam transverse emittance blow-up and its preservation. However, one often finds him-/herself ignorant when he/she tries to explain what was observed in an existing machine or to predict what will happen in a machine under design. There are a number of such examples given in this report. Some of them are even fundamental. These are the challenges. But they are also the directions leading to new achievements. The workshop gladly acknowledged them and promised to work on them.
Tornados and Transverse Oscillations during Prominence Eruption
NASA Astrophysics Data System (ADS)
Banerjee, Dipankar; Chandrashekhar, K.; Morton, Richard; Pant, Vaibhav; Datta, Ajanta
2016-07-01
We report and analyse different phases of a prominence eruption. The winding-unwinding of two footpoints and a tornado like swirling motion is studied. The prominence eruption is observed by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO). This prominence eruption is associated with a CME at a central principal angle of 340 degree, according to the SOHO/LASCO CME catalogue. We can observe the prominence threads and the time distance maps reveal that the loop threads are entangled. We also study the transverse oscillations in the threads. Swirling motions after the eruptions are also quantified and its possible link with the CME kinematics is also studied
Single hadron transverse spin asymmetries from COMPASS
Bradamante, Franco
2007-06-13
Transverse spin physics is an important part of the scientific programme of the COMPASS experiment at CERN. The analysis of the data taken with the target polarized orthogonally to the 160 GeV/c muon beam momentum has allowed to measure for the first time the Collins and Sivers asymmetries of the deuteron. Both for the positive and the negative hadrons produced in semi-inclusive DIS the measured asymmetries are small and, within errors, compatible with zero. New results for {pi}{+-} ans K{+-} are presented here.
Transverse charge densities of N* resonances
Tiator, L.; Vanderhaeghen, M.
2011-10-24
The unitary isobar model MAID2007 has been used to analyze the recent data of pion electroproduction. The model contains all four-star resonances in the region below W = 2 GeV. Both single-Q{sup 2} and Q{sup 2} dependent transition form factors could be obtained for the Delta, Roper, D{sub 13}(1520), S{sub 11}(1535), D{sub 15}(1675), and F{sub 15}(1680) nucleon resonances. Furthermore, we show the empirical transverse charge densities for the Roper, the S11 and D13 resonances, which are evaluated from Fourier transforms of the transition form factors.
Variable weight fiber optic transversal filter
NASA Astrophysics Data System (ADS)
Berry, Mark H.; Gookin, Debra M.
1991-03-01
A transversal filter uses optical components to provide for a wide bandwidth, greater than 10 GHz signal processing capability. RF modulated optical signals are fed over different lengths of optical fibers to impart appropriate tap delays and each is coupled to an integrated optical coupler. Each of the integrated optical couplers have the capability to introduce variable positive and negative weights. Incoherent summing means receive the modulated signals and feed them to an interconnected detector to thereby provide appropriate positive and negative variable weighted signals.
TRANSVERSE OPTICS IMPROVEMENTS FOR RHIC RUN 4.
VAN ZEIJTS,J.
2004-07-05
The magnetic settings in RHIC are driven by an on-line model, and the quality of the resulting lattice functions depend on the correctness of the settings, and knowledge of the magnet transfer-functions. Here we first present the different inputs into the model, including dipole sextupole components, used to set tunes and chromaticities along the ramp. Based on an analysis of measured tunes along the FY03 polarized proton ramp, we present predictions for quadrupole transfer-function changes which have been implemented for the FY04 Au ramp. We show the improved model agreement for tunes along the ramp, and measured transverse phase-advance at store.
Transversely Hessian foliations and information geometry
NASA Astrophysics Data System (ADS)
Boyom, Michel Nguiffo; Wolak, Robert
2015-01-01
A family of probability distributions parametrized by an open domain Λ in Rn defines the Fisher information matrix on this domain which is positive semi-definite. In information geometry the standard assumption has been that the Fisher information matrix is positive definite defining in this way a Riemannian metric on Λ. If we replace the "positive definite" assumption by "0-deformable" condition a foliation with a transvesely Hessian structure appears naturally. We develop the study of transversely Hessian foliations in view of applications in information geometry.
Transverse profile imager for ultrabright electron beams
NASA Astrophysics Data System (ADS)
Ischebeck, Rasmus; Prat, Eduard; Thominet, Vincent; Ozkan Loch, Cigdem
2015-08-01
A transverse profile imager for ultrabright electron beams is presented, which overcomes resolution issues in present designs by observing the Scheimpflug imaging condition as well as the Snell-Descartes law of refraction in the scintillating crystal. Coherent optical transition radiation emitted by highly compressed electron bunches on the surface of the crystal is directed away from the camera, allowing to use the monitor for profile measurements of electron bunches suitable for X-ray free electron lasers. The optical design has been verified by ray tracing simulations, and the angular dependency of the resolution has been verified experimentally. An instrument according to the presented design principles has been used in the SwissFEL Injector Test Facility, and different scintillator materials have been tested. Measurements in conjunction with a transverse deflecting radiofrequency structure and an array of quadrupole magnets demonstrate a normalized slice emittance of 25 nm in the core of a 30 fC electron beam at a pulse length of 10 ps and a particle energy of 230 MeV.
Transversal and longitudinal mixing in compound channels
NASA Astrophysics Data System (ADS)
Besio, G.; Stocchino, A.; Angiolani, S.; Brocchini, M.
2012-12-01
An experimental campaign, based on particle image velocimetry (PIV) measurements of free-surface velocities, forms the basis for an analysis of the mixing processes which occur in a compound-channel flow. The flow mixing is characterized in terms of Lagrangian statistics (absolute dispersion and diffusivity) and of the related mean flow characteristics. Mixing properties strongly depend on the ratiorh between the main channel flow depth (h*mc) and the floodplain depth (h*fp), and three flow classes can be identified, namely shallow, intermediate, and deep flows. In the present study the large time asymptotic behavior of the mixing characteristics is analyzed in terms of the absolute diffusivity in order to characterize typical values of longitudinal and transversal diffusivity coefficients. Various sets of experiments, which cover a wide range of the governing physical parameters, have been performed and the asymptotic values of the absolute diffusivity have been evaluated. The results are then compared with several studies of flow dispersion for both the longitudinal diffusivity coefficient and the transversal turbulent mixing coefficient. The present results highlight a stronger dependence of such coefficients with the flow-depth ratio than with the flow regime (Froude number).
Transversal mixing in the gastrointestinal tract
NASA Astrophysics Data System (ADS)
Vainchtein, Dmitri; Orthey, Perry; Parkman, Henry
2015-11-01
We discuss results of numerical simulations and analytical modeling of transversal intraluminal mixing in the GI tract produced by segmentation and peristaltic contractions. Particles that start in different parts of the small intestine are traced over several contractions and mixing is described using the particles' probability distribution function. We show that there is optimal set of parameters of contractions, such as the depth and frequency, that produces the most efficient mixing. We show that contractions create well-defined advection patterns in transversal direction. The research is inspired by several applications. First, there is the study of bacteria populating the walls of the intestine, which rely on fluid mixing for nutrients. Second, there are gastrointestinal diseases, such as Crohn's disease, which can be treated effectively using a drug delivery capsule through GI tract, for which it is needed to know how long it takes for a released drug to reach the intestinal wall. And finally, certain neurological and muscular deceases change the parameters of contractions, thus reducing the efficiency of mixing. Understanding an admissible range of the parameters (when mixing is still sufficient for biological purposes) may indicate when the medical action is required.
Transversely accelerated ions in the topside ionosphere
NASA Technical Reports Server (NTRS)
Retterer, John M.; Chang, Tom; Jasperse, J. R.
1994-01-01
Data from the rocket campaigns Mechanism in the Auroral Region for Ion Energization (MARIE) and TOpside Probe of the Auroral Zone (TOPAZ) III, within regions of low-altitude transversely accelerated ions, are interpreted to explain the acceleration of the ions. Using the Monte Carlo kinetic technique to evaluate the ion heating produced by the simultaneously observed lower hybrid waves, we find that their observed electric field amplitudes are sufficient to explain the observed ion energies in the MARIE event. Much of the uncertainty in evaluating the efficiency of a plasma wave induced particle heating process which is dependent on a velocity resonance comes from the lack of information on the phase velocities of the waves. In the case of the MARIE observations, our modeling efforts show that features in the ion velocity distribution are consistent with the wave phase velocities inferred from interferometer measurements of wavelengths. The lower hybrid waves with which low-altitude transversely accelerated ions are associated are frequently observed to be concentrated in small-scale wave packets called 'spikelets'. We demonstrate through the scaling of the size of these wave packets that they are consistent with the theory of lower hybrid collapse. Using the Monte Carlo technique, we find that if the lower hybrid field energy is concentrated in these wave packets, it is still adequate to accelerate the ionospheric ions to the observed energies.
Transverse spin and transverse momentum structure of the nucleon from the COMPASS experiment
NASA Astrophysics Data System (ADS)
Sozzi, Federica
2014-03-01
COMPASS is a fixed target experiment at the CERN SPS M2 beam line, taking data since year 2002. Part of the physics programme is dedicated to the study of the transverse spin and transverse momentum structure of the nucleon, by means of semi-inclusive deeply inelastic lepton scattering (SIDIS). For these measurements, data have been collected using transversely polarised proton (NH3) and deuteron (6LiD) targets. A selection of the results on the azimuthal asymmetries measured is presented, with particular focus on the most recent measurements from the data collected in 2007 and 2010 with the proton target. These results exhibit clear signals for the Collins asymmetry, interpreted as a convolution of a non-zero transversity PDF and Collins fragmentation function, and for the Sivers asymmetry which is related to the Sivers function, the most famous and discussed of the TMD PDFs. The data collected with the 6LiD target, have also been recently analysed to search for the azimuthal modulations in the production of hadrons which are expected to be present in the unpolarised part of the SIDIS cross-section. The azimuthal hadron asymmetries, which are related to the Boer-Mulders TMD PDF, show strong and somewhat puzzling kinematical dependencies.
Missing transverse energy performance of the CMS detector
Chatrchyan, Serguei; et al.
2011-09-01
During 2010 the LHC delivered pp collisions with a centre-of-mass energy of 7 TeV. In this paper, the results of comprehensive studies of missing transverse energy as measured by the CMS detector are presented. The results cover the measurements of the scale and resolution for missing transverse energy, and the effects of multiple pp interactions within the same bunch crossings on the scale and resolution. Anomalous measurements of missing transverse energy are studied, and algorithms for their identification are described. The performances of several reconstruction algorithms for calculating missing transverse energy are compared. An algorithm, called missing-transverse-energy significance, which estimates the compatibility of the reconstructed missing transverse energy with zero, is described, and its performance is demonstrated.
Study of electron trapping by a transversely ellipsoidal bubble in the laser wake-field acceleration
Cho, Myung-Hoon; Kim, Young-Kuk; Hur, Min Sup
2013-09-15
We present electron trapping in an ellipsoidal bubble which is not well explained by the spherical bubble model by [Kostyukov et al., Phys. Rev. Lett. 103, 175003 (2009)]. The formation of an ellipsoidal bubble, which is elongated transversely, frequently occurs when the spot size of the laser pulse is large compared to the plasma wavelength. First, we introduce the relation between the bubble size and the field slope inside the bubble in longitudinal and transverse directions. Then, we provide an ellipsoidal model of the bubble potential and investigate the electron trapping condition by numerical integration of the equations of motion. We found that the ellipsoidal model gives a significantly less restrictive trapping condition than that of the spherical bubble model. The trapping condition is compared with three-dimensional particle-in-cell simulations and the electron trajectory in test potential simulations.
Mediterranean diet and faecal microbiota: a transversal study.
Gutiérrez-Díaz, I; Fernández-Navarro, T; Sánchez, B; Margolles, A; González, S
2016-05-18
Despite the existing evidence on the impact of olive oil and red wine on the intestinal microbiota, the effect of the global Mediterranean Diet (MD) has not been sufficiently studied. We explored the association between the adherence to a Mediterranean dietary pattern, and its components, with faecal microbiota in a cohort of adults with non-declared pathology. This transversal study involved 31 adults without a previous diagnosis of cancer, autoimmune or digestive diseases. Based on the data obtained by means of an annual food frequency questionnaire (FFQ), and the information existing in the literature, a Mediterranean Diet Score (MDS) was calculated. Dietary fibre was obtained from Marlett et al. tables and Phenol-Explorer Database was used for phenolic compounds intake. Quantification of microbial groups was performed by Ion Torrent 16S rRNA gene-based analysis and quantification of short-chain fatty acids (SCFAs) was performed using gas chromatography-mass spectrometry (MS). MDS was associated with a higher abundance of Bacteroidetes (p = 0.001), Prevotellacea (p = 0.002) and Prevotella (p = 0.003) and a lower concentration of Firmicutes (p = 0.003) and Lachnospiraceae (p = 0.045). Also, in subjects with MDS ≥ 4, higher concentrations of faecal propionate (p = 0.034) and butyrate (p = 0.018) were detected. These results confirm the complexity of the diet-microbiota interrelationship. PMID:27137178
TRANSVERSE OSCILLATIONS OF A LONGITUDINALLY STRATIFIED CORONAL LOOP SYSTEM
Fathalian, N.; Safari, H. E-mail: safari@znu.ac.i
2010-11-20
Collective transverse coronal loop oscillations seem to be detected in observational studies. In this regard, Luna et al. modeled the collective kink-like normal modes of several cylindrical loop systems using the T-matrix theory. This paper investigates the effects of longitudinal density stratification along the loop axis on the collective kink-like modes of the system of coronal loops. The coronal loop system is modeled as cylinders of parallel flux tubes, with two ends of each loop at the dense photosphere. The flux tubes are considered as uniform magnetic fields, with stratified density along the loop axis which changes discontinuously at the lateral surface of each cylinder. The MHD equations are reduced to solve a set of two coupled dispersion relations for frequencies and wavenumbers, in the presence of a stratification parameter. The fundamental and first overtone frequencies and longitudinal wavenumbers are computed. The previous results are verified for an unstratified coronal loop system. Finally, we conclude that an increased longitudinal density stratification parameter will result in an increase of the frequencies. The frequency ratios, first overtones to fundamentals, are very sensitive functions of the density scale height parameter. Therefore, stratification should be included in dynamics of coronal loop systems. For unstratified coronal loop systems, these ratios are the same as monoloop ones.
Numerical simulation of transverse fuel injection
NASA Technical Reports Server (NTRS)
Mao, Marlon; Riggins, David W.; Mcclinton, Charles R.
1991-01-01
A review of recent work at NASA Langley Research Center to compare the predictions of transverse fuel injector flow fields and mixing performance with experimental results is presented. Various cold (non-reactive) mixing studies were selected for code calibration which include the effects of boundary layer thickness and injection angle for sonic hydrogen injection into supersonic air. Angled injection of helium is also included. This study was performed using both the three-dimensional elliptic and the parabolized Navier-Stokes (PNS) versions of SPARK. Axial solution planes were passed from PNS to elliptic and elliptic to PNS in order to efficiently generate solutions. The PNS version is used both upstream and far downstream of the injector where the flow can be considered parabolic in nature. The comparisons are used to identify experimental deficiencies and computational procedures to improve agreement.
Transverse chromatic aberration after corneal refractive surgery
NASA Astrophysics Data System (ADS)
Anera, R. G.; Jiménez, J. R.; Jiménez del Barco, L.; Hita, E.
2005-05-01
An expression has been deduced theoretically from a schematic-eye model, for the transverse or lateral chromatic aberration (TCA) after refractive surgery. The aim was to investigate analytically how chromatic aberration varies after the emmetropization process. These changes in the TCA have been characterized from changes in corneal asphericity. The results indicate that TCA after refractive surgery diminishes as the degree of myopia increases, a trend contrary to that occurring with monochromatic aberrations, such as spherical or coma. These results can explain the fact that the real deterioration of the visual function under photopic conditions detected in those operated on for myopia is less than expected when only monochromatic aberrations are taken into account.
Radiation emitted by transverse-gradient undulators
NASA Astrophysics Data System (ADS)
Bernhard, Axel; Braun, Nils; Rodríguez, Verónica Afonso; Peiffer, Peter; Rossmanith, Robert; Widmann, Christina; Scheer, Michael
2016-09-01
Conventional undulators are used in synchrotron light sources to produce radiation with a narrow relative spectral width as compared to bending magnets or wigglers. The spectral width of the radiation produced by conventional undulators is determined by the number of undulator periods and by the energy spread and emittance of the electron beam. In more compact electron sources like for instance laser plasma accelerators the energy spread becomes the dominating factor. Due to this effect these electron sources cannot in general be used for high-gain free electron lasers (FELs). In order to overcome this limitation, modified undulator schemes, so-called transverse gradient undulators (TGUs), were proposed and a first superconducting TGU was built at Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany. In this paper simulations of the expected synchrotron radiation spectral distribution are presented. An experimental test with that device is under preparation at the laser wakefield accelerator at the JETI laser at the University of Jena, Germany.
PEP-II Transverse Feedback Electronics Upgrade
Weber, J.; Chin, M.; Doolittle, L.; Akre, R.
2005-05-09
The PEP-II B Factory at the Stanford Linear Accelerator Center (SLAC) requires an upgrade of the transverse feedback system electronics. The new electronics require 12-bit resolution and a minimum sampling rate of 238 Msps. A Field Programmable Gate Array (FPGA) is used to implement the feedback algorithm. The FPGA also contains an embedded PowerPC 405 (PPC-405) processor to run control system interface software for data retrieval, diagnostics, and system monitoring. The design of this system is based on the Xilinx(R) ML300 Development Platform, a circuit board set containing an FPGA with an embedded processor, a large memory bank, and other peripherals. This paper discusses the design of a digital feedback system based on an FPGA with an embedded processor. Discussion will include specifications, component selection, and integration with the ML300 design.
PEP-II Transverse Feedback Electronics Upgrade
Weber, J.M.; Chin, M.J.; Doolittle, L.R.; Akre, R.; /SLAC
2006-03-13
The PEP-II B Factory at the Stanford Linear Accelerator Center (SLAC) requires an upgrade of the transverse feedback system electronics. The new electronics require 12-bit resolution and a minimum sampling rate of 238 Msps. A Field Programmable Gate Array (FPGA) is used to implement the feedback algorithm. The FPGA also contains an embedded PowerPC 405 (PPC-405) processor to run control system interface software for data retrieval, diagnostics, and system monitoring. The design of this system is based on the Xilinx{reg_sign} ML300 Development Platform, a circuit board set containing an FPGA with an embedded processor, a large memory bank, and other peripherals. This paper discusses the design of a digital feedback system based on an FPGA with an embedded processor. Discussion will include specifications, component selection, and integration with the ML300 design.
Coronal seismology using transverse loop oscillations
NASA Astrophysics Data System (ADS)
Verwichte, E.; Foullon, C.; Van Doorsselaere, T.; Smith, H. M.; Nakariakov, V. M.
2009-12-01
Coronal seismology exploits the properties of magnetohydrodynamics in the corona of the Sun to diagnose the local plasma. Therefore, seismology complements direct diagnostic techniques, which suffer from line-of-sight integration or may not give access to all physical quantities. In particular, the seismological exploitation of fast magnetoacoustic oscillations in coronal loops provides information about the global magnetic and density structuring of those loops acting as wave guides. From the oscillation period and damping time it is shown how to obtain information about the local coronal magnetic field as well as the longitudinal and transverse structuring. Furthermore, such studies motivate the development of coronal wave theories, which are also relevant to the coronal heating problem.
First-principles transversal DNA conductance deconstructed.
Zhang, X-G; Krstić, Predrag S; Zikić, Radomir; Wells, Jack C; Fuentes-Cabrera, Miguel
2006-07-01
First-principles calculation of the transverse conductance across DNA fragments placed between gold nanoelectrodes reveals that such conductance describes electron tunneling that depends critically on geometrical rather than electronic-structure properties. By factoring the first-principles result into two simple and approximately independent tunneling factors, we show that the conductances of the A, C, G, and T fragments differ only because of their sizes: the larger is the DNA base, the smaller its distance to the electrode, and the larger its conductance. Because the geometrical factors are difficult to control in an experiment, the direct-current measurements across DNA with gold contact electrodes may not be a convenient approach to DNA sequencing.
First-principles transversal DNA conductance deconstructed
Zhang, Xiaoguang; Krstic, Predrag; Zikic, Radomir; Wells, Jack C; Fuentes-Cabrera, Miguel A
2006-01-01
First-principles calculation of the transverse conductance across DNA fragments placed between gold nanoelectrodes, reveals that such conductance describes electron tunneling that depends critically on geometrical rather than electronic-structure properties. By factoring the first-principles result into two simple and approximately independent tunneling factors, we show that the conductances of the A, C, G, and T fragments differ only because of their sizes: the larger is the DNA base, the smaller is the distance that separates the electrode from the corresponding molecule, and the larger is its conductance. Because the geometrical factors are difficult to control in an experiment, the DC-current measurements across DNA may not be a convenient approach to DNA sequencing.
Transverse effects of microbunch radiative interaction
Derbenev, Ya.S.; Shiltsev, V.D.
1996-06-03
In this article the authors study effects of microbunch cooperative electromagnetic radiation in a bend on transverse beam dynamics. An overtaking radiative interaction between different parts of the bunch results in three major forces variable along the bunch. Longitudinal force leads to energy loss and causes the bunch emittance growth in the bend due to the dispersion effect. Radial force consists of logarithmically large ``Talman`` centrifugal force and smaller centripetal force. Due to general radius-energy dependence in the bend, the ``Talman`` force does not affect beam dynamics while the centripetal force leads to projected emittance growth. Finally, radial and vertical focusing forces lead to trajectory distortions which vary along the bunch. These cooperative forces significantly affect the dynamics of short high-populated bunch in bends.
A Hardware transverse beam frequency response simulator
Ning, J.; Tan, C.Y.; /Fermilab
2005-05-01
We built an electronic instrument that can mimic the transverse beam frequency response. The instrument consists of (1) a time delay circuit with an analog-to-digital converter (ADC) which contains a first-in-first-out random assess memory (FIFO RAM) and a digital-to-analog converter (DAC); (2) a variable phase shifter circuit which is based on an all pass filter with a bandwidth of 25kHz to 30kHz and (3) a commutating filter which is a nonlinear band pass filter. With this instrument, we can dynamically adjust the betatron tune, the synchrotron tune, and the chromaticity. Using this instrument, we are able to test other beam systems without using actual beam.
Studies of Transverse Momentum Distributions of Partons
NASA Astrophysics Data System (ADS)
Avagyan, Harut
2014-03-01
The detailed understanding of the orbital structure of partonic distributions, encoded in Transverse Momentum Dependent (TMD) parton distributions, has been widely recognized as key objective of the JLab 12 GeV upgrade, the polarised pp program at RHIC, and a driving force behind the construction of the Electron Ion Collider. Several proposals have been already approved by the JLab PAC to study TMDs using different spin-azimuthal asymmetries at JLab12 and were awarded the highest physics rating. Although the interest in TMDs has grown enormously we are still in need of fresh theoretical and phenomenological ideas. One of the main challenges still remaining is the extraction of actual 3D parton distribution functions from hard scattering processes in nucleons and nuclei. In this talk, we present an overview of the latest developments and future studies of the TMDs.
Transverse and polarization effects in index-guided vertical-cavity surface-emitting lasers
Torre, M. S.; Masoller, C.; Mandel, Paul
2006-10-15
We study numerically the polarization dynamics of vertical-cavity surface-emitting lasers (VCSEL's) operating in the fundamental transverse mode. We use an extension of the spin-flip model that not only accounts for the vector nature of the laser field, but also considers spatial transverse effects. The model assumes two orthogonal, linearly polarized fields, which are coupled to two carrier populations, associated with different spin sublevels of the conduction and valence bands in the quantum-well active region. Spatial effects are taken into account by considering transverse profiles for the two polarizations, for the two carrier populations, and for the carrier diffusion. The optical profile is the LP{sub 01} mode, suitable for describing index-guided VCSEL's with cylindrical symmetry emitting on the fundamental transverse mode for both polarizations. We find that in small-active-region VCSEL's, fast carrier diffusion induces self-sustained oscillations of the total laser output, which are not present in larger-area devices or with slow carrier diffusion. These self-pulsations appear close to threshold, and, as the injection current increases, they grow in amplitude; however, there is saturation and the self-pulsations disappear at higher injection levels. The dependence of the oscillation amplitude on various laser parameters is investigated, and the results are found to be in good qualitative agreement with those reported by Van der Sande et al. [Opt. Lett. 29, 53 (2004)], based on a rate-equation model that takes into account transverse inhomogeneities through an intensity-dependent confinement factor.
Transverse conformal Killing forms on Kähler foliations
NASA Astrophysics Data System (ADS)
Jung, Seoung Dal
2015-04-01
On a closed, connected Riemannian manifold with a Kähler foliation of codimension q = 2 m, any transverse Killing r(≥ 2) -form is parallel (Jung and Jung, 2012). In this paper, we study transverse conformal Killing forms on Kähler foliations. In fact, if the foliation is minimal, then for any transverse conformal Killing r-form ϕ(2 ≤ r ≤ q - 2), Jϕ is parallel. Here J is defined in Section 4.
Transverse momenta in minimum-bias events at collider energies
Bopp, F.W.; Aurenche, P.; Ranft, J.
1986-04-01
The origin of transverse momenta in minimum-bias events is investigated within the framework of the dual parton model. A Monte Carlo code nicely reproduces almost all available data in a purely soft framework. However, to obtain the multiplicity dependence of the average transverse momentum, it is necessary to attribute transverse momenta to the initial partons which exceed soft values. Without drastically changing the general picture of particle production, the scattering process has to contain a sizable ''semihard'' component.
Transverse momentum correlations of quarks in recursive jet models
NASA Astrophysics Data System (ADS)
Artru, X.; Belghobsi, Z.; Redouane-Salah, E.
2016-08-01
In the symmetric string fragmentation recipe adopted by PYTHIA for jet simulations, the transverse momenta of successive quarks are uncorrelated. This is a simplification but has no theoretical basis. Transverse momentum correlations are naturally expected, for instance, in a covariant multiperipheral model of quark hadronization. We propose a simple recipe of string fragmentation which leads to such correlations. The definition of the jet axis and its relation with the primordial transverse momentum of the quark is also discussed.
Modified Transverse Thoracosternotomy and Cost-Effective Reinforced Sternal Closure.
Costa, Joseph; Sonett, Joshua R; D'Ovidio, Frank
2015-12-01
The bilateral transverse thoracosternotomy clamshell incision provides excellent exposure to the mediastinal structures in double lung transplantation. The use of a modified transverse sternotomy and a figure of 8 configuration with one monofilament metal wire, along with two longitudinal wires across the sternal division, results in greater stability and equally distributed oblique tension. Our described technique was more cost effective and resulted in no incidence of dehiscence. We present our experience using a modified transverse sternotomy and reinforced sternal closure method.
PKU-RBRC Workshop on Transverse Spin
Avakian,H.; Bunce, G.; Yuan, F.
2008-06-30
Understanding the structure of the nucleon is a fundamental question in subatomic physics, and it has been under intensive investigation for the last several years. Modern research focuses in particular on the spin structure of the nucleon. Experimental and theoretical investigations worldwide over the last few decades have established that, contrary to nave quark model expectations, quarks carry only about 30% of the totd spin of the proton. The origin of the remaining spin is the key question in current hadronic physics and also the major driving forces for the current and future experiments, such as RHIC and CEBAF in US, JPARC in Japan, COMPASS at CERN in Europe, FAIR at GSI in Germany. Among these studies, the transverse-spin physics develops actively and rapidly in the last few years. Recent studies reveal that transverse-spin physics is closely related to many fundamental properties of the QCD dynamics such as the factorization, the non-trivial universality of the parton distribution and fragmentation functions. It was very timely to bring together the theorists and experimentalists in this field at this workshop to review and discuss the latest developments and future perspective in hadronic spin physics. This workshop was very success iu many aspects. First of all, it attracted almost every expert working in this field. We had more than eighty participants in total, among them 27 came from the US institutes, 13 from Europe, 3 from Korea, and 2 from Japan. The rest participants came from local institutes in China. Second, we arranged plenty physics presentations, and the program covers all recent progresses made in the last few years. In total, we had 47 physics presentations, and two round table discussions. The discussion sessions were especially very useful and very much appreciated by all participants. In addition, we also scheduled plenty time for discussion in each presentation, and the living discussions impressed and benefited all participants.
Transversity from First Principles in QCD
Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins
2012-02-16
Transversity observables, such as the T-odd Sivers single-spin asymmetry measured in deep inelastic lepton scattering on polarized protons and the distributions which are measured in deeply virtual Compton scattering, provide important constraints on the fundamental quark and gluon structure of the proton. In this talk I discuss the challenge of computing these observables from first principles; i.e.; quantum chromodynamics, itself. A key step is the determination of the frame-independent light-front wavefunctions (LFWFs) of hadrons - the QCD eigensolutions which are analogs of the Schroedinger wavefunctions of atomic physics. The lensing effects of initial-state and final-state interactions, acting on LFWFs with different orbital angular momentum, lead to T-odd transversity observables such as the Sivers, Collins, and Boer-Mulders distributions. The lensing effect also leads to leading-twist phenomena which break leading-twist factorization such as the breakdown of the Lam-Tung relation in Drell-Yan reactions. A similar rescattering mechanism also leads to diffractive deep inelastic scattering, as well as nuclear shadowing and non-universal antishadowing. It is thus important to distinguish 'static' structure functions, the probability distributions computed the target hadron's light-front wavefunctions, versus 'dynamical' structure functions which include the effects of initial- and final-state rescattering. I also discuss related effects such as the J = 0 fixed pole contribution which appears in the real part of the virtual Compton amplitude. AdS/QCD, together with 'Light-Front Holography', provides a simple Lorentz-invariant color-confining approximation to QCD which is successful in accounting for light-quark meson and baryon spectroscopy as well as hadronic LFWFs.
Observation of transverse patterns in an isotropic microchip laser
Chen, Y.F.; Lan, Y.P.
2003-04-01
An isotropic microchip laser is used to study the characteristics of high-order wave functions in a two-dimensional (2D) quantum harmonic oscillator based on the identical functional forms. With a doughnut pump profile, the spontaneous transverse modes are found to, generally, be elliptic and hyperbolic transverse modes. Theoretical analyses reveal that the elliptic transverse modes are analogous to the coherent states of a 2D harmonic oscillator; the formation of hyperbolic transverse modes is a spontaneous mode locking between two identical Hermite-Gaussian modes.
Cooling power of transverse thermoelectrics for cryogenic cooling
NASA Astrophysics Data System (ADS)
Tang, Yang; Ma, Ming; Grayson, M.
2016-05-01
Transverse Peltier coolers have been experimentally and theoretically studied since 1960s due to their capability of achieving cooling in a single-leg geometry. Recently proposed pxn-type transverse thermoelectrics reveal the possibility of intrinsic or undoped transverse coolers that can, in principle, function at cryogenic temperatures, which has drawn more attention to the performance of such transverse coolers. However, unlike longitudinal thermoelectrics, the equations for transverse thermoelectrics cannot be solved analytically. In this study, we therefore calculate the thermoelectric transport in transverse coolers numerically, and introduce a normalized notation, which reduces the independent parameters in the governing equations to a normalized electric field E* and a hot-side transverse figure of merit zTh, only. A numerical study of the maximum cooling temperature difference and cooling power reveals the superior performance of transverse thermoelectric coolers compared to longitudinal coolers with the same figure of merit, providing another motivation in the search for new transverse thermoelectric materials with large figure of merit.
Emergence of transverse spin in optical modes of semiconductor nanowires.
Alizadeh, M H; Reinhard, Björn M
2016-04-18
The transverse spin angular momentum of light has recently received tremendous attention as it adds a new degree of freedom for controlling light-matter interactions. In this work we demonstrate the generation of transverse spin angular momentum by the weakly-guided mode of semiconductor nanowires. The evanescent field of these modes in combination with the transversality condition rigorously accounts for the occurrence of transverse spin angular momentum. The intriguing and nontrivial spin properties of optical modes in semiconductor nanowires are of high interest for a broad range of new applications including chiral optical trapping, quantum information processing, and nanophotonic circuitry. PMID:27137285
Transversity signals in two hadron correlation at COMPASS
Joosten, Rainer
2006-07-11
Measurement of two hadron production introducing the chiral odd interference fragmentation function H{sub 1}{sup arcl} is considered a new probe of the transverse spin distribution {delta}Tq(x). COMPASS is a fixed target experiment on the SPS M2 beamline at CERN. Its target can be polarised both longitudinally and transversely with respect to the polarised 160 GeV/c {mu}+ beam. In 2002, 2003, and 2004, 20% of the beam-time was spent in the transverse configuration on a 6LiD target, allowing the measurement of transversity effects. First results of the analysis of two hadron production will be reported.
Transversity signals in two hadron correlation at COMPASS
Joosten, Rainer
2005-10-06
Measurement of two hadron production introducing the chiral odd interference fragmentation function H{sub 1} is considered a new probe of the transverse spin distribution {delta}Tq(x). COMPASS is a fixed target experiment on the SPS M2 beamline at CERN. Its target can be polarised both longitudinally and transversally with respect to the polarised 160 GeV/c {mu}+ beam. In 2002, 2003, and 2004, 20% of the beam-time was spent in the transverse configuration on a 6LiD target, allowing the measurement of transversity effects. First results of the analysis of two hadron production will be reported.
The First Measurement of Neutron Transversity on a Transversely Polarized 3He Target
Yi Qiang
2009-12-01
We recently measured the neutron target single spin asymmetry in the semi-inclusive deep inelastic 3He (e,e',pi+/-)X reactions with a transversely polarized 3He target. The experiment was performed in Hall A at Jefferson Lab from October 2008 to February 2009. Pions were detected in the high-resolution spectrometer in coincidence with scattered electrons detected by the BigBite spectrometer. The kinematic coverage focuses on the valence quark region, x = 0.1 - 0.4, at Q2 = 1-3 (GeV/c)2. With good particle identifications using a RICH detector and an aerogel Cherenkov counter, data on kaons were obtained at the same time. The data from this experiment, when combined with the world data, will provide constraints on the Transversity and Sivers distributions on both u-quark and d-quark in the valence quark region.
NASA Astrophysics Data System (ADS)
Reich, Michael Todd
Gigahertz Transverse Electromagnetic (GTEM) cells are commonly used to determine radiated emissions from electrically small objects. A correlation algorithm is used to relate the measurements taken in a GTEM cell with measurements that would be seen at an Open Air Test Site (OATS). The correlation algorithm can be broken into two portions. The first portion relates voltage measurements made in a GTEM to the terms of a multipole expansion approximating the radiated emissions of the test object. The second portion determines the equivalent radiated emissions at an OATS due to the terms of the multipole expansion. To date, these correlation algorithms assume that the Equipment Under Test (EUT) is placed at the transverse center of the GTEM cell. In this work a new correlation algorithm is introduced. Instead of assuming that the EUT is located at the transverse center of the cell, this algorithm makes use of different transverse positions in the cell to determine the multipole moments. The method requires a total of six measurements and requires that both the magnitude and phase of the emissions from the EUT are available. The method is numerically robust and can easily be extended to compute higher-order multipole moments. To date, phase measurements in a GTEM cell have only been demonstrated in a rudimentary fashion. This work also introduces the concept of the virtual port as a means of measuring the magnitude and phase of the emissions from an EUT within a GTEM cell. Utilizing a fiber-optic link, it is possible to create a second, virtual port within the GTEM cell.
TRANSVERSE OSCILLATIONS OF A COOLING CORONAL LOOP
Morton, R. J.; Erdelyi, R. E-mail: Robertus@sheffield.ac.u
2009-12-10
Here we present an investigation into how cooling of the plasma influences the oscillation properties (e.g., eigenfunctions and eigenfrequencies) of transverse (i.e., kink) magnetohydrodynamic (MHD) waves in a compressible magnetic flux tube embedded in a gravitationally stratified and uniformly magnetized atmosphere. The cooling is introduced via a temperature-dependent density profile. A time-dependent governing equation is derived and an approximate zeroth-order solution is then obtained. From this the influence of cooling on the behavior of the eigenfrequencies and eigenfunctions of the transverse MHD waves is determined for representative cooling timescales. It is shown analytically, as the loop cools, how the amplitude of the perturbations is found to decrease as time increases. For cooling timescales of 900-2000 s (as observed in typical EUV loops), it is shown that the cooling has important and relevant influence on the damping times of loop oscillations. Next, the theory is put to the test. The damping due to cooling is fitted to a representative observation of standing kink oscillation of EUV loops. It is also shown with an explicit approximate analytical form, how the period of the fundamental and first harmonic of the kink mode changes with time as the loop cools. A consequence of this is that the value of the period ratio P {sub 1}/P {sub 2}, a tool that is popular in magneto-seismological studies in coronal diagnostics, decreases from the value of a uniform loop, 2, as the temperature decreases. The rate of change in P {sub 1}/P {sub 2} is dependent upon the cooling timescale and is well within the observable range for typical EUV loops. Further to this, the magnitude of the anti-node shift of the eigenfunctions of the first harmonic is shown to continually increase as the loop cools, giving additional impetus to the use of spatial magneto-seismology of the solar atmosphere. Finally, we suggest that measurements of the rate of change in the
Strong transverse coupling in the Tevatron
Annala, G; Carson, J; Edwards, Don; Gelfand, N; Harding, D; Johnson, T; Johnstone, J; Martens, M; Sen, T; Syphers, Mike
2003-03-01
The Tevatron was designed with an extensive set of correction and adjustment magnets built into the spool pieces in recognition of the circumstance that a superconducting synchrotron was not as easy to modify as its conventional forebearers. Recently, concern has mounted at the high excitation of the skew quadrupole correctors. The purpose of this note is to account for this situation. When slow extraction was attempted from the Main Ring in the summer of 1970 horizontal-vertical coupling prevented adequate transverse oscillation growth for efficient slow spill. This situation was corrected by an 8 mrad roll of each of twelve equi-spaced quadrupoles [1]. In order to avoid a repetition of this problem in the Tevatron, an extremely strong skew quadrupole circuit was built in at the outset. When the Tevatron was commissioned only 4$ of the capability of this circuit was required. Now, 20 years later, the excitation of this skew quadrupole circuit is approximately 60%. Other skew quadrupole correctors were installed in the neighborhood of the long straight sections, and for a variety of reasons the number of elements in the strong circuit was reduced from 48 to 42. These are relatively minor changes in the present context. Recall that in the normal Tevatron tuning process the skew quad circuits are adjusted to minimize the difference between the horizontal and vertical tunes to the level of {Delta}{nu}{sub min} {approx} 0.003. Normally the horizontal-vertical coupling is not observed directly by orbit measurements during this procedure. it was recognized that the strength of the skew quadrupole settings would imply an uncorrected minimum tune difference of 0.2 units. Clearly, with the skew quad circuit turned off the coupling of the orbital motion should be easily observable. In the following sections, the authors describe the recent Tevatron studies that exhibit the transverse coupling and the analyses that link these observations to the long term development of a
Communicating with Transverse Modes of Light
NASA Astrophysics Data System (ADS)
Rodenburg, Brandon
Shannon's theory of communication created a set of tools for studying complex systems in an abstract and powerful way, providing the core foundations for the field of information theory. This thesis uses these ideas to provide a framework for studying the transverse degree of freedom of an optical field, appropriate for both classical and quantum states of light. This degree of freedom is in principle an unbounded space, providing a complex resource for encoding a large amount of information. This work focuses on studying the physical limits to the information of this space, both in terms of fundamental theoretical limitations as well as practical limitations due to experimental implementation and error. This thesis will pay particular interest to the design and implementation of a quantum key distribution system encoded using a particular set of transverse modes for encoding known as orbital angular momentum states, which represent normal modes of a typical free-space optical system. This specific technological implementation provides a motivation that acts to unify many of the themes in this work including quantum state preparation, state detection or discrimination, and state evolution or propagation. Additionally, such a setup gives a specific physical meaning to the abstract tools we will be utilizing as the information that we will be quantifying can be thought of as a measure of the possible complexity or information content of a single photon. Chapter 1 provides a brief introduction to information theory and the basic concepts and tools that are used throughout this work, as well as a basic introduction to quantum key distribution. Chapter 2 theoretically explores the fundamental limits of the information capacity of a channel due to diffraction, as well as computes the communication modes of a channel using a normal mode approach to propagation. Chapter 3 concerns the experimental implementation of a free-space quantum key distribution system including
17. Interior detail, pilaster on transverse wall at the northeast ...
17. Interior detail, pilaster on transverse wall at the northeast end of the Machine Shop, Roundhouse Machine Shop Extension, Southern Pacific Railroad Carlin Shops, view to northeast (90mm lens). Note the offset top of the pilaster, a feature common to all interior transverse wall pilasters. - Southern Pacific Railroad, Carlin Shops, Roundhouse Machine Shop Extension, Foot of Sixth Street, Carlin, Elko County, NV
Transverse wake field simulations for the ILC acceleration structure
Solyak, N.; Lunin, A.; Yakovlev, V.; /Fermilab
2008-06-01
Details of wake potential simulation in the acceleration structure of ILC, including the RF cavities and input/HOM couplers are presented. Transverse wake potential dependence is described versus the bunch length. Beam emittance dilution caused by main and HOM couplers is estimated, followed by a discussion of possible structural modifications allowing a reduction of transverse wake potential.
Extraction of Transversity from COMPASS and Belle Data
NASA Astrophysics Data System (ADS)
Bradamante, Franco
2016-02-01
The valence transversity distributions of the u- and the d-quarks have been extracted point-by-point from single-hadron production and dihadron production data measured in semi-inclusive deep inelastic scattering and in e+e annihilation. The transversity distributions are found to be compatible with each other and with previous analyses.
THE RESUMMED HIGGS BOSON TRANSVERSE MOMENTUM DISTRIBUTION AT THE LHC.
KULESZA,A.STERMAN,G.VOGELSANG,W.
2003-12-08
We apply QCD resummation techniques to study the transverse momentum distribution of Higgs bosons produced via gluon-gluon fusion at the LHC. In particular we focus on the joint resummation formalism which resume both threshold and transverse momentum corrections simultaneously. A comparison of results obtained in the joint and the standard recoil resummation frameworks is presented.
Phenomenology of transverse spin: Past, present and future
NASA Astrophysics Data System (ADS)
Boglione, Mariaelena; Prokudin, Alexei
2016-06-01
We summarize the most significant aspects in the study of transverse spin phenomena over the last few decades, focusing on Semi-Inclusive Deep Inelastic Scattering processes and hadronic production in e + e - annihilations. The phenomenology of transverse-momentum-dependent distribution and fragmentation functions will be reviewed in an in-depth analysis of the most recent developments and of the future perspectives.
Exploring universality of transversity in proton-proton collisions
NASA Astrophysics Data System (ADS)
Radici, Marco; Ricci, Alessandro M.; Bacchetta, Alessandro; Mukherjee, Asmita
2016-08-01
We consider the azimuthal correlations of charged hadron pairs with large total transverse momentum and small relative momentum, produced in proton-proton collisions with one transversely polarized proton. One of these correlations directly probes the chiral-odd transversity parton distribution in connection with a chiral-odd interference fragmentation function. We present predictions for this observable based on previous extractions of transversity (from charged pion pair production in semi-inclusive deep-inelastic scattering) and of the interference fragmentation function (from the production of back-to-back charged pion pairs in electron-positron annihilations). All analyses are performed in the framework of collinear factorization. We compare our predictions to the recent data on proton-proton collisions released by the STAR Collaboration at RHIC, and we find them reasonably compatible. This comparison confirms for the first time the predicted role of transversity in proton-proton collisions, and it allows us to test its universality.
Coupling of transverse and longitudinal waves in piano strings.
Etchenique, Nikki; Collin, Samantha R; Moore, Thomas R
2015-04-01
The existence of longitudinal waves in vibrating piano strings has been previously established, as has their importance in producing the characteristic sound of the piano. Modeling of the coupling between the transverse and longitudinal motion of strings indicates that the amplitude of the longitudinal waves are quadratically related to the transverse displacement of the string, however, experimental verification of this relationship is lacking. In the work reported here this relationship is tested by driving the transverse motion of a piano string at only two frequencies, which simplifies the task of unambiguously identifying the constituent signals. The results indicate that the generally accepted relationship between the transverse motion and the longitudinal motion is valid. It is further shown that this dependence on transverse displacement is a good approximation when a string is excited by the impact of the hammer during normal play. PMID:25920829
Coupling of transverse and longitudinal waves in piano strings.
Etchenique, Nikki; Collin, Samantha R; Moore, Thomas R
2015-04-01
The existence of longitudinal waves in vibrating piano strings has been previously established, as has their importance in producing the characteristic sound of the piano. Modeling of the coupling between the transverse and longitudinal motion of strings indicates that the amplitude of the longitudinal waves are quadratically related to the transverse displacement of the string, however, experimental verification of this relationship is lacking. In the work reported here this relationship is tested by driving the transverse motion of a piano string at only two frequencies, which simplifies the task of unambiguously identifying the constituent signals. The results indicate that the generally accepted relationship between the transverse motion and the longitudinal motion is valid. It is further shown that this dependence on transverse displacement is a good approximation when a string is excited by the impact of the hammer during normal play.
NASA Astrophysics Data System (ADS)
Chandanayaka, Tharaka; Azarmi, Fardad
2014-05-01
In the present study, cold spraying technique was used to fabricate a metal matrix composite (MMC) that consists of Ni matrix and 20 vol.% Ni3Al particles at two different particle sizes as reinforcement. This study intends to investigate the effect of reinforcement particle size on microstructural and mechanical properties of cold sprayed MMCs. Two different Ni3Al powders with nominal particle size of -45 to +5 and +45 to 100 μm were used as reinforcement in this study. Cold sprayed Ni-Ni3Al samples were subjected to the microstructural observation and characterization prior to any mechanical testing. Then, samples were tested using nano-indentation, Knoop hardness, Vickers hardness, and Resonance frequency to evaluate their mechanical properties. No significant changes were observed in microstructural characteristics due to different particle sizes. The results obtained from a variety of mechanical testings indicated that the increasing reinforcement particle size resulted in the slight reduction of mechanical properties such as elastic modulus and hardness in cold sprayed MMCs. The mechanical interlock between deposited particles defines the bonding strength in cold sprayed samples. Small size particles have a higher velocity and impact resulting in stronger interlock between deformed particles.
Transverse relaxation of scalar-coupled protons.
Segawa, Takuya F; Baishya, Bikash; Bodenhausen, Geoffrey
2010-10-25
In a preliminary communication (B. Baishya, T. F. Segawa, G. Bodenhausen, J. Am. Chem. Soc. 2009, 131, 17538-17539), we recently demonstrated that it is possible to obtain clean echo decays of protons in biomolecules despite the presence of homonuclear scalar couplings. These unmodulated decays allow one to determine apparent transverse relaxation rates R(2) (app) of individual protons. Herein, we report the observation of R(2) (app) for three methyl protons, four amide H(N) protons, and all 11 backbone H(α) protons in cyclosporin A. If the proton resonances overlap, their R(2) (app) rates can be measured by transferring their magnetization to neighboring (13)C nuclei, which are less prone to overlap. The R(2) (app) rates of protons attached to (13)C are faster than those attached to (12)C because of (13)C-(1)H dipolar interactions. The differences of these rates allow the determination of local correlation functions. Backbone H(N) and H(α) protons that have fast decay rates R(2) (app) also feature fast longitudinal relaxation rates R(1) and intense NOESY cross peaks that are typical of crowded environments. Variations of R(2) (app) rates of backbone H(α) protons in similar amino acids reflect differences in local environments.
Transverse form factors of [sup 117]Sn
Baghaei, H.; Dubach, J.; Frodyma, M.B.; Hicks, R.S.; Miskimen, R.A.; Peterson, G.A.; Rokni, S.H. ); Hotta, A. ); Suzuki, T. )
1993-08-01
Transverse elastic and inelastic form factors for low-lying levels in [sup 117]Sn have been measured by 180[degree] electron scattering in the momentum transfer range [ital q][sub eff]=1.1--2.4 fm[sup [minus]1]. The simple independent-particle model fails to account for these data, predicting form factors that are much too large. In better quantitative agreement with the data are the results of more detailed calculations that allow for configuration mixing of valence nucleons, as well as first-order core polarization. As in the similar case of [sup 205]Tl, these calculations successfully predict the presence of a deep diffraction minimum observed in the intermediate [ital q] region of the elastic [ital M]1 form factor. Nevertheless, the overall description of the data by the detailed calculations remains quantitatively unsatisfactory. A more complete understanding of these data may rely upon the consideration of multiparticle-multihole configurations outside the 0[h bar][omega] basis space.
Quark transversity distribution in perturbative QCD: light-front Hamiltonian approach
NASA Astrophysics Data System (ADS)
Mukherjee, A.; Chakrabarti, D.
2001-05-01
To resolve the current ambiguity in the splitting function corresponding to the quark transversity distribution h1(x), we calculate h1(x) for a dressed quark in light-front Hamiltonian perturbation theory. Our result agrees with the expected form of the splitting function found in the literature and disagrees with the recent calculation in M. Meyer-Hermann et al., hep-ph/0012226. We emphasize the importance of quark mass in h1(x) in perturbative QCD and show its connection with a part of gT.
Piekarczyk, Wojciech; Kata, Dariusz
2016-09-01
The paper presents the methodology and results of the ultrasound determination of material constants of anisotropic materials belonging to the transversely isotropic system. Ultrasound through-transmission method was used for determining material constants. Based on the measurements of velocities of longitudinal and transverse ultrasounds waves propagation, respectively polarized in required directions all the elastic and the material constant of the test materials were determined. Measurements of all the velocities necessary to determine the elastic constants were performed on a specially prepared individual samples. The tests were carried out on porous polycrystalline anisotropic graphites of anisotropy in Young's modulus of up to 26% and Al2O3 composites with up to 30% of hBN causing anisotropy of Young's modulus of up to 50%. It was found that for all tested samples the value of Young's modules and modules stiffness decreasing with increasing porosity in the graphites and increasing content of hBN in Al2O3.
Piekarczyk, Wojciech; Kata, Dariusz
2016-09-01
The paper presents the methodology and results of the ultrasound determination of material constants of anisotropic materials belonging to the transversely isotropic system. Ultrasound through-transmission method was used for determining material constants. Based on the measurements of velocities of longitudinal and transverse ultrasounds waves propagation, respectively polarized in required directions all the elastic and the material constant of the test materials were determined. Measurements of all the velocities necessary to determine the elastic constants were performed on a specially prepared individual samples. The tests were carried out on porous polycrystalline anisotropic graphites of anisotropy in Young's modulus of up to 26% and Al2O3 composites with up to 30% of hBN causing anisotropy of Young's modulus of up to 50%. It was found that for all tested samples the value of Young's modules and modules stiffness decreasing with increasing porosity in the graphites and increasing content of hBN in Al2O3. PMID:27395009
Transverse intensity transformation by laser amplifiers
NASA Astrophysics Data System (ADS)
Litvin, Igor A.; King, Gary; Collett, Oliver J. P.; Strauss, Hencharl J.
2015-03-01
Lasers beams with a specific intensity profile such as super-Gaussian, Airy or Dougnut-like are desirable in many applications such as laser materials processing, medicine and communications. We propose a new technique for laser beam shaping by amplifying a beam in an end-pumped bulk amplifier that is pumped with a beam that has a modified intensity profile. Advantages of this method are that it is relatively easy to implement, has the ability to reshape multimode beams and is naturally suited to high power/energy beams. Both three and four level gain materials can be used as amplifier media. However, a big advantage of using three level materials is their ability to attenuate of the seed beam, which enhances the contrast of the shaping. We first developed a numerical method to obtain the required pump intensity for an arbitrary beam transformation. This method was subsequently experimentally verified using a three level system. The output of a 2.07 μm seed laser was amplified in a Ho:YLF bulk amplifier which was being pumped by a 1.89 μm Tm:YLF laser which had roughly a TEM10 Hermit Gaussian intensity profile. The seed beam was amplified from 0.3 W to 0.55 W at the full pump power of 35 W. More importantly, the beam profile in one transverse direction was significantly shaped from Gaussian to roughly flat-top, as the model predicted. The concept has therefore been shown to be viable and can be used to optimise the beam profile for a wide range of applications.
Paleogene depositional framework of western Transverse ranges
Dickinson, W.R.
1988-03-01
In the western Transverse Ranges, widespread Paleogene sequences (mid-Paleocene to mid-Oligocene) accumulated to thicknesses locally in excess of 5000 m. The Paleogene basin occupied a complex forearc setting located near the offshore Franciscan trench, but distant from the inland Laramide orogenic system, where magmatism was quiescent during the interval of most rapid sedimentation. The pre-Tertiary substratum, largely masked by its Paleogene cover, was probably disrupted by transpressional and/or transtensional tectonics associated with separate episodes of mid-Cretaceous sinistral and Late Cretaceous (to Paleocene.) dextral dislocation of the continental margin. Paleogene strata include diachronous facies of intertonguing deep-marine, shallow-marine, marginal-marine, and nonmarine clastic strata representing varied depositional systems. Turbidite assemblages include both progradational and retrogradational phases of canyon-fed submarine fans and delta-fed submarine ramps. Exposed shelf-break successions were deposited offshore from strandline complexes fringing delta margins and broad coastal plains. Sparse but diagnostic nonclastic facies include local algal carbonate edifices built on isolated submarine banks, and minor lagoonal beds of algal carbonates and gypsiferous evaporites associated with emergent delta platforms. The complex Paleogene forearc basin was flanked on the northeast by Salinian basement rocks and on the southwest by a tectonic ridge of subduction complex uplifted along the Paleogene trench-slope break. The present geographic distribution of Paleogene facies tracts is fully compatible with proposed Neogene tectonic rotations of panel-like basin segments, bounded by antithetic sinistral faults within the dextral San Andreas system, as detected by recent paleomagetic investigations.
Velocity analysis for transversely isotropic media
Alkhalifah, T.; Tsvankin, I.
1994-08-01
The main difficulty in extending seismic processing to anisotropic media is the recovery of anisotropic velocity fields from surface reflection data. Velocity analysis for transversely isotropic (TI) media can be done by inverting the dependence of P-wave moveout velocities on the ray parameter. P-wave NMO velocity in homogeneous TI media with a vertical symmetry axis depends just on the zero-dip value V{sub nmo} and a new effective parameter {eta} that reduces to the difference between Thomsen parameters {epsilon} and {delta} in the limit of weak anisotropy. It is possible to obtain {eta} and reconstruct the NMO velocity as a function of ray parameter using moveout velocities for two different dips. Moreover, V{sub nmo}(0) and {eta} determine not only the NMO velocity, but also also long-spread (nonhyperbollic) P-wave moveout for horizontal reflectors and time-migration impulse response. Inversion of dip-moveout information allows performance of all time-processing steps in TI media using only surface P-wave data. Isotropic time-processing methods remain entirely valid for elliptical anisotropy ({epsilon} = {delta}). Accurate time-to-depth conversion, however, requires the vertical velocity V{sub P0} be resolved independently. If I-P0 is known, then allisotropies {epsilon} and {delta} can be found by inverting two P-wave NMO velocities corresponding to a horizontal and a dipping reflector. If no information is available, all three parameters (V {sub P0}, {epsilon}, and {delta}) can be obtained by combining inversion results with shear-wave information. such as the P-SV or SV-SV wave NMO velocities for a horizontal reflector. Generalization of Tsvankin`s single-layer NMO equation for layered anisotropic media with a dipping reflector provides a basis for extending anisotropic velocity analysis to vertically inhomogeneous media. The influence of a stratified overburden on moveout velocity can be stripped through a Dix-type differentiation procedure.
Dynamic response of fiber bundle under transverse impact.
Lu, Wei-Yang; Song, Bo
2010-03-01
There has been a very high demand in developing efficient soft body armors to protect the military and law enforcement personnel from ballistic or explosive attack. As a basic component in the soft body armor, fibers or fiber bundles play a key role in the performance against ballistic impact. In order to study the ballistic-resistant mechanism of the soft body armor, it is desirable to understand the dynamic response of the fiber bundle under transverse impact. Transverse wave speed is one important parameter because a faster transverse wave speed can make the impact energy dissipate more quickly. In this study, we employed split Hopkinson pressure bar (SHPB) to generate constant high-speed impact on a Kevlar fiber bundle in the transverse direction. The deformation of the fiber bundle was photographed with high-speed digital cameras. The transverse wave speeds were experimentally measured at various transverse impact velocities. The experimental results can also be used to quantitatively verify the current analytical models or to develop new models to describe the dynamic response of fiber bundle under transverse impact.
Relation between intraocular pressure and size of transverse sinuses.
Kantarci, Mecit; Dane, Senol; Gumustekin, Kenan; Onbas, Omer; Alper, Fatih; Okur, Adnan; Aslankurt, Murat; Yazici, Ahmet Taylan
2005-01-01
There are asymmetries in the sizes of transverse sinus and intraocular pressure. The purpose of this study was to investigate possible relationships between the asymmetry of transverse sinuses in TOF MR venography and intraocular pressures of right and left eyes. In this study, subjects were 63 male and 42 female medical school students, aged 18-21 years (mean+/-SD; 19.72+/-0.67 years). Subjects with neurological and ophthalmologic disease, particularly dural sinus thrombosis, myopia, trauma and glaucoma, were excluded the study. Subjects were divided into five groups according to the magnitudes of the right- and left-transverse sinuses in MR venography results. There is a functional relation between intraocular pressures of the right and left eyes and asymmetry of the transverse sinus. If the transverse sinus on one side is larger and its venous drainage is greater, the intraocular pressure of the eye on this side is lower. It can be speculated that the transverse sinus size may be associated with pathogenesis of diseases with increased intraocular pressure such as glaucoma. We aim to determine the relation between the size and drainage of transverse sinuses in TOF MR venography and intraocular pressure in patients with open-angle glaucoma in our next study. PMID:15647949
Impact parameter dependent potentials and transverse single spin asymmetries
NASA Astrophysics Data System (ADS)
Alhalholy, Tareq
Using the Eikonal approximation, we study single spin azimuthal asymmetry in elastic and in-elastic lepton-nucleon scattering for the case of transversely polarized nucleons with unpolarized lepton beam. We follow two different approaches to evaluate the asymmetry. In the first approach we utilize the convolution theory of Fourier transforms to express the nucleon potential that appears in the Coulomb phase formula in terms of the nucleon's Dirac and Pauli form factors in the nucleon current density for transversely polarized nucleons. In the second approach, we explicitly evaluate the potential due to transversely polarized nucleons in impact parameter space. The result shows that this potential is asymmetric about an axis normal to the transverse plane; a result that is consistent with the fact that the nucleon charge density (or the unpolarized impact parameter dependent parton distribution function) is transversely distorted for transverse nucleon polarization, which is not the case for longitudinal polarization of the nucleon. To further confirm this fact, we calculate the average transverse momentum experienced by the scattered electron. This quantity is zero considering scattering from a classical dipole moment while our results show a non-zero average transverse momentum even for scattering from a neutron; there we get a negative value for the average momentum, and a positive one (and larger in magnitude) for the case of a proton. The sign of the average transverse momentum is directly related to the sign of the single spin asymmetry, where it is negative in the case of a neutron target and positive for a proton. The expansion of the Eikonal amplitude reveals that the asymmetry is due to the interference of the one and two photon exchange Eikonal amplitudes. In both of the above mentioned approaches, we evaluate the one and two photon exchange amplitudes, from which the asymmetry is found for different parametrizations of the form factors.
FIRST DIRECT MEASUREMENTS OF TRANSVERSE WAVES IN SOLAR POLAR PLUMES USING SDO/AIA
Thurgood, J. O.; Morton, R. J.; McLaughlin, J. A.
2014-07-20
There is intense interest in determining the precise contribution of Alfvénic waves propagating along solar structures to the problems of coronal heating and solar wind acceleration. Since the launch of SDO/AIA, it has been possible to resolve transverse oscillations in off-limb solar polar plumes and recently McIntosh et al. concluded that such waves are energetic enough to play a role in heating the corona and accelerating the fast solar wind. However, this result is based on comparisons to Monte Carlo simulations and confirmation via direct measurements is still outstanding. Thus, this Letter reports on the first direct measurements of transverse wave motions in solar polar plumes. Over a four hour period, we measure the transverse displacements, periods, and velocity amplitudes of 596 distinct oscillations observed in the 171 Å channel of SDO/AIA. We find a broad range of non-uniformly distributed parameter values which are well described by log-normal distributions with peaks at 234 km, 121 s, and 8 km s{sup –1}, and mean and standard deviations of 407 ± 297 km, 173 ± 118 s, and 14 ± 10 km s{sup –1}. Within standard deviations, our direct measurements are broadly consistent with previous results. However, accounting for the whole of our observed non-uniform parameter distribution we calculate an energy flux of 9-24 W m{sup –2}, which is 4-10 times below the energy requirement for solar wind acceleration. Hence, our results indicate that transverse magnetohydrodynamic waves as resolved by SDO/AIA cannot be the dominant energy source for fast solar wind acceleration in the open-field corona.
Measuring the full transverse beam matrix using a single octupole
NASA Astrophysics Data System (ADS)
Ögren, J.; Ruber, R.; Ziemann, V.; Farabolini, W.
2015-07-01
We propose a method to fully determine the transverse beam matrix using a simple setup consisting of two steering magnets, an octupole field and a screen. This works in principle for any multipole field, i.e., sextupole, octupole magnet or a radio frequency structure with a multipole field. We have experimentally verified the method at the Compact Linear Collider Test Facility 3 at CERN using a Compact Linear Collider accelerating structure, which has an octupole component of the radio frequency fields. By observing the position shifts of the beam centroid together with changes in transverse beam size on a screen, we determined the full transverse beam matrix, with all correlations.
Transverse thermal expansion of carbon fiber/epoxy matrix composites
NASA Technical Reports Server (NTRS)
Helmer, J. F.; Diefendorf, R. J.
1983-01-01
Thermal expansion coefficients and moduli of elasticity have been determined experimentally for a series of epoxy-matrix composites reinforced with carbon and Kevlar fibers. It is found that in the transverse direction the difference between the properties of the fiber and the matrix is not as pronounced as in the longitudinal direction, where the composite properties are fiber-dominated. Therefore, the pattern of fiber packing tends to affect transverse composite properties. The transverse properties of the composites tested are examined from the standpoint of the concept of homogeneity defined as the variation of packing (or lack thereof) throughout a sample.
First order tune shift calculations for transverse betatron dynamics
Garavaglia, T.
1991-09-01
An effective Hamiltonian, with non-linear magnetic multipole terms and momentum dispersion contributions, is used to obtain the first order tune-shift results for transverse betatron motion for protons in the Superconducting Super Collider (SSC). This Hamiltonian is represented in terms of action angle variables, and analytical results are obtained using symbolic algebra methods. Mathematical derivations of the transverse multipole expansion and of the transverse betatron equations, using an invariant action and curvilinear coordinates, are given in the appendices. Numerical and graphical tune-space results are given that illustrate the dependence of tune-shifts on injection amplitude and momentum spread. 10 refs., 7 figs.
Broadband gold nanoantennas arrays with transverse dimension effects.
Su, Chen-Wei; Chen, Kuo-Ping
2016-08-01
Broadband resonance in gold paired-rods nanoantennas and paired-strips gratings is investigated when the nanostructure's transverse (non-polarization) dimension is changed from paired-rods to paired-strips. Increasing the transverse dimension blue shifts the resonance wavelength and widens its bandwidth due to cancellation of the magnetic field between nanoantennas. A derived resistor-inductor-capacitor (RLC) equivalent circuit model verifies the nanostructures' resonance when elongating the transverse dimensions. Paired-strips gratings have a bandwidth 2.04 times that of paired-rods nanoantennas. PMID:27505744
A novel photonic Doppler velocimetry for transverse velocity measurement
Chen Guanghua; Wang Detian; Liu Jun; Meng Jianhua; Liu Shouxian; Yang Qingguo
2013-01-15
A fiber interferometry for transverse velocity measurement has been developed. This diagnostic is similar to photonic Doppler velocimetry in the way in which laser propagates and couples. The interferometer mainly consists of a fiber coupler, an emitting probe, and two receiving probes. A pair of scattered laser beams mix in the coupler and generates fringes with frequency proportional to transverse velocity. Measurement of transverse velocity is independent of longitudinal velocity. The feasibility of the technique has been verified by rotating wheel experiment and shock loading experiment.
Analysis of Slice Transverse Emittance Evolution ina Photocathode RF Gun
Huang, Z.; Ding, Y.; Qiang, J.; /LBL, Berkeley
2007-10-17
The slice transverse emittance of an electron beam is of critical significance for an x-ray FEL. In a photocathode RF gun, the slice transverse emittance is not only determined by the emission process, but also influenced strongly by the non-linear space charge effect. In this paper, we study the slice transverse emittance evolution in a photocathode RF gun using a simple model that includes effects of RF acceleration, focusing, and space charge force. The results are compared with IMPACT-T space charge simulations and may be used to understand the development of the slice emittance in an RF gun.
Transverse Spin Experiments with the PHENIX Detector at RHIC
NASA Astrophysics Data System (ADS)
Makdisi, Yousef
2009-03-01
The PHENIX experiment took data with transversely polarized proton beams from RUN1 in 2001 through RUN8 in 2008 and measured several transverse single spin asymmetries in various reactions in two kinematic regions; mid rapidity, near XF˜0 in inclusive neutral pion and charged hadron production at transverse momenta up to 5 GeV/c with results consistent with zero, and the forward rapidity, where large asymmetries were observed in inclusive neutral pion production similar to those previously seen by the STAR and BRAHMS detectors. Also presented are the unique PHENIX results on asymmetries in inclusive open charm and charmonium production along with PHENIX upgrades and future plans.
Transverse momentum resummation for dijet correlation in hadronic collisions
NASA Astrophysics Data System (ADS)
Sun, Peng; Yuan, C.-P.; Yuan, Feng
2015-11-01
We study transverse momentum resummation for the azimuthal angular correlation in dijet production in hadron collisions based on the Collins-Soper-Sterman formalism. The complete one-loop calculations are carried out in the collinear framework for the differential cross sections at low imbalance transverse momentum between the two jets. Important cross-checks are performed to demonstrate that the soft divergences are canceled out between different diagrams and, in particular, for those associated with the final state jets. The leading and subleading logarithms are identified. All order resummation is derived following the transverse momentum dependent factorization at this order. Its phenomenological applications are also presented.
Penetrating intracranial gunshot wound transecting the right transverse sinus
Beaty, Narlin Bennet; Diaz, Cara; Crandall, Kenneth; Sansur, Charles
2012-01-01
A 23-year-old man sustained a gunshot wound to the posterior head. Imaging demonstrated a transection of the right transverse sinus, a retained bullet fragment and significant cerebellar oedema. The patient emergently underwent suboccipital decompression associated with brisk bleeding from the transverse sinus. Reported examples of surgical management of cerebral venous sinuses include: packing, grafting, patching and ligation. Our patient had a codominant transverse sinus and underwent successful unilateral ligation. His postoperative course was uneventful, however, he did require a ventriculoperitoneal shunt. He was subsequently discharged to rehab with a favourable outcome. PMID:22987903
NASA Astrophysics Data System (ADS)
Ghods, M.; Johnson, L.; Lauer, M.; Grugel, R. N.; Tewari, S. N.; Poirier, D. R.
2016-05-01
Hypoeutectic Al-7 wt% Si and Al-19 wt% Cu alloys were directionally solidified upward in a Bridgman furnace through a range of constant growth speeds and thermal gradients. Though processing is thermo-solutally stable, flow initiated by gravity-independent advection at, slightly leading, central dendrites moves rejected solute out ahead and across the advancing interface. Here any lagging dendrites are further suppressed which promotes a curved solid-liquid interface and the eventual dendrite "clustering" seen in transverse sections (dendrite "steepling" in longitudinal orientations) as well as extensive radial macrosegregation. Both aluminum alloys showed considerable macrosegregation at the low growth speeds (10 and 30 μm s-1) but not at higher speed (72 μm s-1). Distribution of the fraction eutectic-constituent on transverse sections was determined in order to quantitatively describe radial macrosegregation. The convective mechanisms leading to dendrite-steepling were elucidated with numerical simulations, and their results compared with the experimental observations.
Interfacial dynamnics at sliding Ta/Al interfaces
NASA Astrophysics Data System (ADS)
Hammerberg, J. E.; Ravelo, R.; Holian, B. L.; Germann, T. C.; Olson, C. J.
2002-03-01
We present results of large-scale MD simulations of sliding Al(100)/Ta(100) interfaces at high shearing velocties. The Ta and Al interactions are modeled using EAM potentials. We discuss the structural evolution near the interface and compare our results with known 2-dimensional simulations which make use of Lennard-Jones potentials but in similar scaled-velocity regimes, namely, 0.01
Noncritical quadrature squeezing in two-transverse-mode optical parametric oscillators
Navarrete-Benlloch, Carlos; Roldan, Eugenio; Valcarcel, German J. de; Romanelli, Alejandro
2010-04-15
In this article we explore the quantum properties of a degenerate optical parametric oscillator when it is tuned to the first family of transverse modes at the down-converted frequency. Recently we found [C. Navarrete-Benlloch et al., Phys. Rev. Lett. 100, 203601 (2008)] that above threshold a TEM{sub 10} mode following a random rotation in the transverse plane emerges in this system (we denote it as the bright mode), breaking thus its rotational invariance. Then, owing to the mode orientation being undetermined, we showed that the phase quadrature of the transverse mode orthogonal to this one (denoted as the dark mode) is perfectly squeezed at any pump level and without an increase in the fluctuations on its amplitude quadrature (which seems to contradict the uncertainty principle). In this article we go further in the study of this system and analyze some important features not considered previously. First we show that the apparent violation of the uncertainty principle is just that -'apparent' - as the conjugate pair of the squeezed quadrature is not another quadrature but the orientation of the bright mode (which is completely undetermined in the long term). We also study a homodyne scheme in which the local oscillator is not perfectly matched to the dark mode, as this could be impossible in real experiments due to the random rotation of the mode, showing that even in this case large levels of noise reduction can be obtained (also including the experimentally unavoidable phase fluctuations). Finally, we show that neither the adiabatic elimination of the pump variables nor the linearization of the quantum equations are responsible for the remarkable properties of the dark mode (which we prove analytically and through numerical simulations, respectively), which were simplifying assumptions used in Navarrete-Benlloch et al. [Phys. Rev. Lett. 100, 203601 (2008)]. These studies show that the production of noncritically squeezed light through spontaneous rotational
46 CFR 154.174 - Transverse contiguous hull structure.
Code of Federal Regulations, 2011 CFR
2011-10-01
... heating system under § 154.178. ... structure of a vessel having cargo containment systems without secondary barriers must meet the standards of...) The transverse contiguous hull structure of a vessel having cargo containment systems with...
46 CFR 154.174 - Transverse contiguous hull structure.
Code of Federal Regulations, 2012 CFR
2012-10-01
... heating system under § 154.178. ... structure of a vessel having cargo containment systems without secondary barriers must meet the standards of...) The transverse contiguous hull structure of a vessel having cargo containment systems with...
46 CFR 154.174 - Transverse contiguous hull structure.
Code of Federal Regulations, 2013 CFR
2013-10-01
... heating system under § 154.178. ... structure of a vessel having cargo containment systems without secondary barriers must meet the standards of...) The transverse contiguous hull structure of a vessel having cargo containment systems with...
46 CFR 154.174 - Transverse contiguous hull structure.
Code of Federal Regulations, 2014 CFR
2014-10-01
... heating system under § 154.178. ... structure of a vessel having cargo containment systems without secondary barriers must meet the standards of...) The transverse contiguous hull structure of a vessel having cargo containment systems with...
Detail East Pier Elevation, Transverse Section, Detail Roof Plan As ...
Detail East Pier Elevation, Transverse Section, Detail Roof Plan As Found - Sulphite Railroad Bridge, Former Boston & Maine Railroad (originally Tilton & Franklin Railroad) spanning Winnipesautee River, Franklin, Merrimack County, NH
Transverse section through the Grand Lodge and Grand Chapter rooms ...
Transverse section through the Grand Lodge and Grand Chapter rooms of James H. Windrim and George Summerss neoclassical competition design for the New Masonic Temple, Philadelphia, 1867 - Masonic Temple, 1 North Broad Street, Philadelphia, Philadelphia County, PA
Onset of transverse instabilities of confined dark solitons
NASA Astrophysics Data System (ADS)
Hoefer, M. A.; Ilan, B.
2016-07-01
We investigate propagating dark soliton solutions of the two-dimensional defocusing nonlinear Schrödinger or Gross-Pitaevskii (NLS-GP) equation that are transversely confined to propagate in an infinitely long channel. Families of single, vortex, and multilobed solitons are computed using a spectrally accurate numerical scheme. The multilobed solitons are unstable to small transverse perturbations. However, the single-lobed solitons are stable if they are sufficiently confined along the transverse direction, which explains their effective one-dimensional dynamics. The emergence of a transverse modulational instability is characterized in terms of a spectral bifurcation. The critical confinement width for this bifurcation is found to coincide with the existence of a propagating vortex solution and the onset of a "snaking" instability in the dark soliton dynamics that, in turn, give rise to vortex or multivortex excitations. These results shed light on the superfluidic hydrodynamics of dispersive shock waves in Bose-Einstein condensates and nonlinear optics.
The Tucker technique: conservative molar inlays preserving the transverse ridge.
Hess, T A; Wadhwani, C P K
2012-01-01
Conservation of healthy tooth structure should be the aim of any restorative procedure. Two inlays may be an ideal choice for the treatment of maxillary molars to preserve the transverse ridge and maintain structural integrity.
Site Plan and Transverse Section Chickamauga National Military Park ...
Site Plan and Transverse Section - Chickamauga National Military Park Tour Roads, Gordon's Slough Bridge, At the confluence of Alexander's Bridge Road and Gordon's Slough, southeast of Alexander's Bridge, Fort Oglethorpe, Catoosa County, GA
46 CFR 154.174 - Transverse contiguous hull structure.
Code of Federal Regulations, 2010 CFR
2010-10-01
... heating system under § 154.178. ... structure of a vessel having cargo containment systems without secondary barriers must meet the standards of...) The transverse contiguous hull structure of a vessel having cargo containment systems with...
Transverse strain measurements using fiber optic grating based sensors
NASA Technical Reports Server (NTRS)
Udd, Eric (Inventor)
1998-01-01
A system and method to sense the application of transverse stress to an optical fiber which includes a light source that producing a relatively wide spectrum light beam. The light beam is reflected or transmitted off of an optical grating in the core of an optical fiber that is transversely stressed either directly or by the exposure to pressure when the fiber is bifringent so that the optical fiber responds to the pressure to transversely stress its core. When transversely stressed, the optical grating produces a reflection or transmission from the light beam that has two peaks or minimums in its frequency spectrum whose spacing and/or spread are indicative of the forces applied to the fiber. One or more detectors sense the reflection or transmissions from the optical grating to produce an output representative of the applied force. Multiple optical gratings and detectors may be employed to simultaneously measure temperature or the forces at different locations along the fiber.
Negative ion source with low temperature transverse divergence optical system
Whealton, John H.; Stirling, William L.
1986-01-01
A negative ion source is provided which has extremely low transverse divergence as a result of a unique ion focusing system in which the focal line of an ion beam emanating from an elongated, concave converter surface is outside of the ion exit slit of the source and the path of the exiting ions. The beam source operates with a minimum ion temperature which makes possible a sharply focused (extremely low transverse divergence) ribbon like negative ion beam.
Negative ion source with low temperature transverse divergence optical system
Whealton, J.H.; Stirling, W.L.
1985-03-04
A negative ion source is provided which has extremely low transverse divergence as a result of a unique ion focusing system in which the focal line of an ion beam emanating from an elongated, concave converter surface is outside of the ion exit slit of the source and the path of the exiting ions. The beam source operates with a minimum ion temperature which makes possible a sharply focused (extremely low transverse divergence) ribbon like negative ion beam.
Transverse effects in plasma wakefield acceleration at FACET - Simulation studies
Adli, E.; Hogan, M.; Frederico, J.; Litos, M. D.; An, W.; Mori, W.
2012-12-21
We investigate transverse effects in the plasma-wakefield acceleration experiments planned and ongoing at FACET. We use PIC simulation tools, mainly QuickPIC, to simulate the interaction of the drive electron beam and the plasma. In FACET a number of beam dynamics knobs, including dispersion and bunch length knobs, can be used to vary the beam transverse characteristics in the plasma. We present simulation results and the status of the FACET experimental searches.
Cavernoma of the conus medullaris mimicking transverse myelitis.
Balasubramaniam, Srikant; Mahore, Amit
2013-02-01
We present an interesting case of conus medullaris cavernoma that was initially treated as transverse myelitis. Haemorrhagic lumbar puncture led us to perform magnetic resonance (MR) imaging, which showed the presence of a cavernous angioma at the D12-L1 level. The total excision of the lesion was followed by dramatic improvement. We suggest that MR imaging be performed early in all suspected cases of transverse myelitis so that emergency surgical intervention can be offered before the development of permanent neurological deficits.
Transverse Gradient Undulators and FEL operating with large energy spread
NASA Astrophysics Data System (ADS)
Ciocci, F.; Dattoli, G.; Sabia, E.
2015-12-01
Undulators exhibiting a gradient of the field in the transverse direction have been proposed to mitigate the effects of the gain dilution in Free Electron Laser devices operating with large energy spread. The actual use of the device depends on the realization of a field distribution with quasi-vanishing quadrupolar terms in the tapering directions. We analyze the effect of a Transverse Gradient Undulator on the FEL operation and critically review the possibility of an appropriate field implementation.
Muscle force depends on the amount of transversal muscle loading.
Siebert, Tobias; Till, Olaf; Stutzig, Norman; Günther, Michael; Blickhan, Reinhard
2014-06-01
Skeletal muscles are embedded in an environment of other muscles, connective tissue, and bones, which may transfer transversal forces to the muscle tissue, thereby compressing it. In a recent study we demonstrated that transversal loading of a muscle with 1.3Ncm(-2) reduces maximum isometric force (Fim) and rate of force development by approximately 5% and 25%, respectively. The aim of the present study was to examine the influence of increasing transversal muscle loading on contraction dynamics. Therefore, we performed isometric experiments on rat M. gastrocnemius medialis (n=9) without and with five different transversal loads corresponding to increasing pressures of 1.3Ncm(-2) to 5.3Ncm(-2) at the contact area between muscle and load. Muscle loading was induced by a custom-made plunger which was able to move in transversal direction. Increasing transversal muscle loading resulted in an almost linear decrease in muscle force from 4.8±1.8% to 12.8±2% Fim. Compared to an unloaded isometric contraction, rate of force development decreased from 20.2±4.0% at 1.3Ncm(-2) muscle loading to 34.6±5.7% at 5.3Ncm(-2). Experimental observation of the impact of transversal muscle loading on contraction dynamics may help to better understand muscle tissue properties. Moreover, applying transversal loads to muscles opens a window to analyze three-dimensional muscle force generation. Data presented in this study may be important to develop and validate muscle models which enable simulation of muscle contractions under compression and enlighten the mechanisms behind. PMID:24725439
Graphene transverse electric surface plasmon detection using nonreciprocity modal discrimination
NASA Astrophysics Data System (ADS)
Chamanara, Nima; Caloz, Christophe
2016-08-01
We present a magnetically biased graphene-ferrite structure discriminating the transverse electric (TE) and transverse magnetic (TM) plasmonic modes of graphene. In this structure, the graphene TM plasmons interact reciprocally with the structure. In contrast, the graphene TE plasmons exhibit nonreciprocity. This nonreciprocity is manifested in unidirectional TE propagation in a frequency band close to the interband threshold frequency. The proposed structure provides a unique platform for the experimental demonstration of the unusual existence of the TE plasmonic mode in graphene.
Theoretical study of transverse-longitudinal emittance coupling
Qin, H; Davidson, R C; Chung, M; Barnard, J J; Wang, T F
2011-04-14
The effect of a weakly coupled periodic lattice in terms of achieving emittance exchange between the transverse and longitudinal directions is investigated using the generalized Courant-Snyder theory for coupled lattices. Recently, the concept and technique of transverse-longitudinal emittance coupling have been proposed for applications in the Linac Coherent Light Source and other free-electron lasers to reduce the transverse emittance of the electron beam. Such techniques can also be applied to the driver beams for the heavy ion fusion and beam-driven high energy density physics, where the transverse emittance budget is typically tighter than the longitudinal emittance. The proposed methods consist of one or several coupling components which completely swap the emittances of one of the transverse directions and the longitudinal direction at the exit of the coupling components. The complete emittance exchange is realized in one pass through the coupling components. In the present study, we investigate the effect of a weakly coupled periodic lattice in terms of achieving emittance exchange between the transverse and longitudinal directions. A weak coupling component is introduced at every focusing lattice, and we would like to determine if such a lattice can realize the function of emittance exchange.
Experimental detection of transverse particle movement with structured light.
Rosales-Guzmán, Carmelo; Hermosa, Nathaniel; Belmonte, Aniceto; Torres, Juan P
2013-10-02
One procedure widely used to detect the velocity of a moving object is by using the Doppler effect. This is the perceived change in frequency of a wave caused by the relative motion between the emitter and the detector, or between the detector and a reflecting target. The relative movement, in turn, generates a time-varying phase which translates into the detected frequency shift. The classical longitudinal Doppler effect is sensitive only to the velocity of the target along the line-of-sight between the emitter and the detector (longitudinal velocity), since any transverse velocity generates no frequency shift. This makes the transverse velocity undetectable in the classical scheme. Although there exists a relativistic transverse Doppler effect, it gives values that are too small for the typical velocities involved in most laser remote sensing applications. Here we experimentally demonstrate a novel way to detect transverse velocities. The key concept is the use of structured light beams. These beams are unique in the sense that their phases can be engineered such that each point in its transverse plane has an associated phase value. When a particle moves across the beam, the reflected light will carry information about the particle's movement through the variation of the phase of the light that reaches the detector, producing a frequency shift associated with the movement of the particle in the transverse plane.
Transversity signals in two hadron correlation at COMPASS
Joosten, Rainer
2007-06-13
Over the last couple of years, transverse spin physics has gained increasing attention as well from theoretical as from experimental side. To fully specify the quark structure of the nucleon at the twist-two level, the transverse spin distribution function {delta}Tq(x) has to be taken into account. The measurement of two hadron production introducing the chiral odd interference fragmentation function H{sub 1} is considered a new probe of the transverse spin distribution function.COMPASS is a fixed target experiment on the SPS M2 beamline at CERN. Its target can be polarised both longitudinally and transversally with respect to the polarised 160 GeV/c {mu}+ beam. In 2002, 2003, and 2004, 20% of the beam-time was spent in the transverse configuration on a 6LiD target, allowing the measurement of transversity effects on a deuterium target. The results of the analysis of two hadron production based on the full statistics on the deuterium target are reported.
What does the transverse carpal ligament contribute to carpal stability?
Vanhees, Matthias; Verstreken, Frederik; van Riet, Roger
2015-02-01
Background The transverse carpal ligament is well known for its involvement in carpal tunnel syndrome, and sectioning of this ligament remains the definite treatment for this pathology. Some authors believe that the transverse carpal ligament is an important stabilizer of the carpal arch, whereas others do not consider it to be significant. Several studies have been performed, both in vivo and in in vitro. Sectioning of the transverse carpal ligament does not seem to have any effect on the width of the carpal arch in the unloaded condition. However, patients will load the arch during their activities of daily living. Materials and Methods A cadaveric study was done with distraction of the carpal bones before and after sectioning the transverse carpal ligament. Results With the transverse carpal ligament intact, the carpal arch is mobile, with distraction leading up to 50% widening of the arch. Sectioning of the transverse carpal ligament resulted in a significant widening of the carpal arch by a further 30%. Conclusions Loading of the carpal arch after sectioning of the transeverse carapal ligament leads to a significant increase in intracarpal mobility. This will inevitably influence carpal kinematics in the patient and might be responsible for some complications after simple carpal tunnel releases, such as pillar pain, palmar tenderness, and loss of grip strength.
Experimental detection of transverse particle movement with structured light.
Rosales-Guzmán, Carmelo; Hermosa, Nathaniel; Belmonte, Aniceto; Torres, Juan P
2013-01-01
One procedure widely used to detect the velocity of a moving object is by using the Doppler effect. This is the perceived change in frequency of a wave caused by the relative motion between the emitter and the detector, or between the detector and a reflecting target. The relative movement, in turn, generates a time-varying phase which translates into the detected frequency shift. The classical longitudinal Doppler effect is sensitive only to the velocity of the target along the line-of-sight between the emitter and the detector (longitudinal velocity), since any transverse velocity generates no frequency shift. This makes the transverse velocity undetectable in the classical scheme. Although there exists a relativistic transverse Doppler effect, it gives values that are too small for the typical velocities involved in most laser remote sensing applications. Here we experimentally demonstrate a novel way to detect transverse velocities. The key concept is the use of structured light beams. These beams are unique in the sense that their phases can be engineered such that each point in its transverse plane has an associated phase value. When a particle moves across the beam, the reflected light will carry information about the particle's movement through the variation of the phase of the light that reaches the detector, producing a frequency shift associated with the movement of the particle in the transverse plane. PMID:24085150
Transverse bed slope effects in an annular flume
NASA Astrophysics Data System (ADS)
Baar, Anne; Kleinhans, Maarten; de Smit, Jaco; Uijttewaal, Wim
2016-04-01
Large scale morphology, in particular bar dimensions and bifurcation dynamics, are greatly affected by the deflection of sediment transport on transverse bed slopes due to gravity and by helical flows. However, existing transverse bed slope predictors are based on a small set of experiments with a minor range of flow conditions and sediment sizes, and do not account for the presence of bedforms. In morphological modelling the deflection angle is therefore often calibrated on measured morphology. Our objective is to experimentally quantify the transverse slope effect for a large range of near-bed flow conditions and sediment sizes (0.17 - 4 mm) to test existing predictors, in order to improve morphological modelling of rivers and estuaries. We have conducted about 400 experiments in an annular flume, which functions as an infinitely long bended flume and therefore avoids boundary effects. Flow is generated by rotating the lid of the flume, while the intensity of the helical flow can be decreased by counterrotating the bottom of the flume. The equilibrium transverse slope that develops during the experiments is a balance between the transverse bed slope effect and the bed shear stress caused by the helical flow. We obtained sediment mobilities from no motion to sheet flow, ranging across bedload and suspended load. Resulting equilibrium transverse slopes show a clear trend with varying sediment mobilities and helical flow intensities that deviate from typical power relations with Shields number. As an end member we found transversely horizontal beds by counterrotation that partially cancelled the helical flow near the bed, which allows us to quantify helical flow. The large range in sediment mobilities caused different bed states from ripples and dunes to sheet flow that affect near-bed flow, which cause novel nonlinear relations between transverse slope and Shields number. In conclusion, our results show for a wide range of conditions and sediments that transverse
NASA Astrophysics Data System (ADS)
Tang, Yang; Koblmüller, G.; Riedl, H.; Grayson, M.
2016-03-01
Transverse thermoelectrics promise entirely new strategies for integrated cooling elements for optoelectronics. The recently introduced p × n-type transverse thermoelectric paradigm indicates that the most important step to engineering artiﬁcial transverse thermoelectrics is to create alternate p- and n-doped layers with orthogonally oriented anisotropic conductivity. This paper studies an approach to creating extreme anisotropic conductivity in bulk-doped semiconductor thin ﬁlms via ion implantation. This approach deﬁnes an array of parallel conduction channels with photolithographic patterning of an SiO2 mask layer, followed by proton implantation. With a 10 μm channel width and 20 μm pitch, both n-type and p-type Al0.42 Ga0.58As thin ﬁlms demonstrate a conductivity anisotropy ratio σ /σ⊥ > 104 at room temperature, while the longitudinal resistivity along the channel direction after implantation only increased by a factor of 3.3 ˜ 3.6. This approach can be readily adapted to other semiconductor materials for artiﬁcial p × n-type transverse thermoelectrics as other applications.
Transverse-coherence properties of the FEL at the LCLS
Ding, Yuantao; Huang, Zhirong; Ocko, Samuel A.; /MIT, Cambridge, Dept. Phys.
2010-09-02
The recently commissioned Linac Coherent Light Source is an x-ray free-electron laser at the SLAC National Accelerator Laboratory, which is now operating at x-ray wavelengths of 20-1.2 Angstrom with peak brightness nearly ten orders of magnitude beyond conventional synchrotron sources. Understanding of coherence properties of the radiation from SASE FELs at LCLS is of great practical importance for some user experiments. We present the numerical analysis of the coherence properties at different wavelengths based on a fast algorithmusing ideal and start-end simulated FEL fields. The sucessful commissioning and operation of the linac coherent light source (LCLS) [1] has demonstrated that the x-ray free-electron laser (FEL) has come of age; these types of x-ray sources are poised to revolutionize the ultra-fast x-ray sciences. The LCLS and other hard x-ray FELs under construction are based on the principle of self-amplified spontaneous emission (SASE) [2, 3], where the amplification process starts from the shot noise in the electron beam. A large number of transverse radiation modes are also excited when the electron beam enters the undulator. The FEL collective instability in the electron beam causes the modulation of the electron density to increase exponentially, and after sufficient undulator distances, a single transverse mode starts to dominate. As a result, SASE FEL is almost fully coherent in the transverse dimension. Understanding of transverse coherence properties of the radiation from SASE FELs is of great practical importance. The longitudinal coherence properties of SASE FELs have been studied before [4]. Some studies on the transverse coherence can be found in previous papers, for example, in ref. [5, 6, 7, 8, 9]. In this paper, we first discuss a new numerical algorithm based on Markov chain Monte Carlo techniques to calculate the FEL transverse coherence. Then we focus on the numerical analysis of the LCLS FEL transverse coherence.
Pion transverse charge density and the edge of hadrons
NASA Astrophysics Data System (ADS)
Carmignotto, Marco; Horn, Tanja; Miller, Gerald A.
2014-08-01
We use the world data on the pion form factor for space-like kinematics and a technique previously used to extract the proton transverse densities to extract the transverse pion charge density and its uncertainty due the incomplete knowledge of the pion form factor at large values of Q2 and the experimental uncertainties. The pion charge density at small values of impact parameter b < 0.1 fm is dominated by this incompleteness error while the range between 0.1-0.3 fm is relatively well constrained. A comparison of pion and proton transverse charge densities shows that the pion is denser than the proton for values of b <0.2fm. The pion and proton transverse charge densities seem to be the same for values of b =0.3-0.6 fm. Future data from Thomas Jefferson National Accelerator Facility (JLab) 12 GeV and the Electron-Ion Collider (EIC) will increase the dynamic extent of the form factor data to higher values of Q2 and thus reduce the uncertainties in the extracted pion transverse charge density.
Transverse dispersion: From laboratory experiments to field applications
NASA Astrophysics Data System (ADS)
Grathwohl, Peter; Rügner, Hermann
2016-04-01
Transverse dispersion is relevant for dilution of contaminant plumes in groundwater and in many cases controls the length of steady state plumes during natural attenuation. Also dissolution kinetics of NAPLs in porous media and mass transfer of vapor phase compounds across the capillary fringe (e.g. supply of oxygen) is limited by transverse dispersion. In bench scale laboratory experiments typically very small dispersion coefficients are observed. Transverse dispersivities determined in DNAPL pool dissolution experiments in coarse sands are less than 0.1 mm which agrees with results from lab experiments on dilution of tracers and transfer of oxygen across the capillary fringe. Such low dispersivities lead to long-term persistence of DNAPL pools of many decades to centuries which is confirmed e.g. for chlorinated solvents and coal tars by observations at contaminated sites. However, larger scale investigations, e.g. determination of the length of steady state plumes or reduction of mass fluxes of biodegradable compounds suggest that transverse dispersivities at field scale are up to 3 orders of magnitude higher (1 -10 cm). Reasons for this discrepancy are still unclear, but may be partly explained by processes enhancing transverse mixing such as flow focusing due to aquifer geometries or high permeability inclusions and helical groundwater flow induced by herringbone structures in sediments.
Realizing vector meson dominance with transverse charge densities
Gerald Miller, Mark Strikman, Christian Weiss
2011-10-01
The transverse charge density in a fast-moving nucleon is represented as a dispersion integral of the imaginary part of the Dirac form factor in the timelike region (spectral function). At a given transverse distance b the integration effectively extends over energies in a range {radical}t {approx}< 1/b, with exponential suppression of larger values. The transverse charge density at peripheral distances thus acts as a low-pass filter for the spectral function and allows one to select energy regions dominated by specific t-channel states, corresponding to definite exchange mechanisms in the spacelike form factor. We show that distances b {approx} 0.5 - 1.5 fm in the isovector density are maximally sensitive to the {rho} meson region, with only a {approx}10% contribution from higher-mass states. Soft-pion exchange governed by chiral dynamics becomes relevant only at larger distances. In the isoscalar density higher-mass states beyond the {omega} are comparatively more important. The dispersion approach suggests that the positive transverse charge density in the neutron at b {approx} 1 fm, found previously in a Fourier analysis of spacelike form factor data, could serve as a sensitive test of the isoscalar strength in the {approx}1 GeV mass region. In terms of partonic structure, the transverse densities in the vector meson region b {approx} 1 fm support an approximate mean-field picture of the motion of valence quarks in the nucleon.
Transverse Spin Azimuthal Asymmetries in SIDIS at COMPASS: Multidimensional Analysis
NASA Astrophysics Data System (ADS)
Parsamyan, Bakur
2016-02-01
COMPASS is a high-energy physics experiment operating at the SPS at CERN. Wide physics program of the experiment comprises study of hadron structure and spectroscopy with high energy muon and hadrons beams. As for the muon-program, one of the important objectives of the COMPASS experiment is the exploration of the transverse spin structure of the nucleon via spin (in)dependent azimuthal asymmetries in single-hadron production in deep inelastic scattering of polarized leptons off transversely polarized target. For this purpose a series of measurements were made in COMPASS, using 160 GeV/c longitudinally polarized muon beam and transversely polarized 6LiD (in 2002, 2003 and 2004) and NH3 (in 2007 and 2010) targets. The experimental results obtained by COMPASS for unpolarized target azimuthal asymmetries, Sivers and Collins effects and other azimuthal observables play an important role in the general understanding of the three-dimensional nature of the nucleon. Giving access to the entire twsit-2 set of transverse momentum dependent parton distribution functions and fragmentation functions COMPASS data triggers constant theoretical interest and is being widely used in phenomenological analyses and global data fits. In this review main focus is given to the very recent results obtained by the COMPASS collaboration from first ever multi-dimensional extraction of transverse spin asymmetries.
Longitudinal evaluation of foetal transverse lie using ultrasonography.
Oyinloye, Olalekan I; Okoyomo, Alexander A
2010-03-01
The purpose of this study was to assess the risk of persistence of transverse lie detected earlier in pregnancy and associated predisposing factors using follow-up ultrasound (US). A longitudinal study was carried out from January 2004 to august 2004 at Federal Medical centre, Lokoja, Nigeria. All singleton pregnancies, with ultrasound diagnosis of transverse lie, between 24-28 weeks were followed to term. At 24-28 weeks, 183 fetuses presented with transverse lie. Thirty seven were lost to follow-up; out of the remaining 146 babies, 22 persisted to term. Overall persistence rate was 15.1%. No identifiable predisposing factors were seen in 91.1%, placenta previa in 5.5%, lower segment fibroids in 2.7%, and ectopic kidney in 0.7%. In conclusion, transverse lie detected early in pregnancy is transient, and majority would convert to a longitudinal lie at term. Potential predisposing factors highlighted above increases the risk of persistent transverse lie at term, with placenta previa and lower segment fibroids being the major predisposing factors.
Studies of Transverse Momentum Dependent Parton Distributions and Bessel Weighting
NASA Astrophysics Data System (ADS)
Gamberg, Leonard
2015-04-01
We present a new technique for analysis of transverse momentum dependent parton distribution functions, based on the Bessel weighting formalism. Advantages of employing Bessel weighting are that transverse momentum weighted asymmetries provide a means to disentangle the convolutions in the cross section in a model independent way. The resulting compact expressions immediately connect to work on evolution equations for transverse momentum dependent parton distribution and fragmentation functions. As a test case, we apply the procedure to studies of the double longitudinal spin asymmetry in SIDIS using a dedicated Monte Carlo generator which includes quark intrinsic transverse momentum within the generalized parton model. Using a fully differential cross section for the process, the effect of four momentum conservation is analyzed using various input models for transverse momentum distributions and fragmentation functions. We observe a few percent systematic offset of the Bessel-weighted asymmetry obtained from Monte Carlo extraction compared to input model calculations. Bessel weighting provides a powerful and reliable tool to study the Fourier transform of TMDs with controlled systematics due to experimental acceptances and resolutions with different TMD model inputs. Work is supported by the U.S. Department of Energy under Contract No. DE-FG02-07ER41460.
Studies of Transverse Momentum Dependent Parton Distributions and Bessel Weighting
NASA Astrophysics Data System (ADS)
Gamberg, Leonard
2015-10-01
We present a new technique for analysis of transverse momentum dependent parton distribution functions, based on the Bessel weighting formalism. Advantages of employing Bessel weighting are that transverse momentum weighted asymmetries provide a means to disentangle the convolutions in the cross section in a model independent way. The resulting compact expressions immediately connect to work on evolution equations for transverse momentum dependent parton distribution and fragmentation functions. As a test case, we apply the procedure to studies of the double longitudinal spin asymmetry in SIDIS using a dedicated Monte Carlo generator which includes quark intrinsic transverse momentum within the generalized parton model. Using a fully differential cross section for the process, the effect of four momentum conservation is analyzed using various input models for transverse momentum distributions and fragmentation functions. We observe a few percent systematic offset of the Bessel-weighted asymmetry obtained from Monte Carlo extraction compared to input model calculations. Bessel weighting provides a powerful and reliable tool to study the Fourier transform of TMDs with controlled systematics due to experimental acceptances and resolutions with different TMD model inputs. Work is supported by the U.S. Department of Energy under Contract No. DE-FG02-07ER41460.
Transverse commensurability effect for vortices on periodic pinning arrays
Reichhardt, Charles; Reichhardt, Cynthia J
2008-01-01
Using computer simulations, we demonstrate a type of commensurability that occurs for vortices moving longitudinally through periodic pinning arrays in the presence of an additional transverse driving force. As a function of vortex density, there is a series of broad maxima in the transverse critical depinning force that do not fall at the matching fields where the number of vortices equals an integer multiple of the number of pinning sites. The commensurability effects are associated with dynamical states in which evenly spaced structures consisting of one or more moving rows of vortices form between rows of pinning sites. Remarkably, the critical transverse depinning force can be more than an order of magnitude larger than the longitudinal depinning force.
Nucleon helicity and transversity parton distributions from lattice QCD
NASA Astrophysics Data System (ADS)
Chen, Jiunn-Wei; Cohen, Saul D.; Ji, Xiangdong; Lin, Huey-Wen; Zhang, Jian-Hui
2016-10-01
We present the first lattice-QCD calculation of the isovector polarized parton distribution functions (both helicity and transversity) using the large-momentum effective field theory (LaMET) approach for direct Bjorken-x dependence. We first review the detailed steps of the procedure in the unpolarized case, then generalize to the helicity and transversity cases. We also derive a new mass-correction formulation for all three cases. We then compare the effects of each finite-momentum correction using lattice data calculated at Mπ ≈ 310 MeV. Finally, we discuss the implications of these results for the poorly known antiquark structure and predict the sea-flavor asymmetry in the transversely polarized nucleon.
Anomalous postcritical refraction behavior for certain transversely isotropic media
Fa, L.; Brown, R.L.; Castagna, J.P.
2006-01-01
Snell's law at the boundary between two transversely isotropic media with a vertical axis of symmetry (VTI media) can be solved by setting up a fourth order polynomial for the sine of the reflection/transmission angles. This approach reveals the possible presence of an anomalous postcritical angle for certain transversely isotropic media. There are thus possibly three incident angle regimes for the reflection/refraction of longitudinal or transverse waves incident upon a VTI medium: precritical, postcritical/preanomalous, and postanomalous. The anomalous angle occurs for certain strongly anisotropic media where the required root to the phase velocity equation must be switched in order to obey Snell's law. The reflection/transmission coefficients, polarization directions, and the phase velocity are all affected by both the anisotropy and the incident angle. The incident critical angles are also effected by the anisotropy. ?? 2006 Acoustical Society of America.
Effect of dephasing on DNA sequencing via transverse electronic transport
Zwolak, Michael; Krems, Matt; Pershin, Yuriy V; Di Ventra, Massimiliano
2009-01-01
We study theoretically the effects of dephasing on DNA sequencing in a nanopore via transverse electronic transport. To do this, we couple classical molecular dynamics simulations with transport calculations using scattering theory. Previous studies, which did not include dephasing, have shown that by measuring the transverse current of a particular base multiple times, one can get distributions of currents for each base that are distinguishable. We introduce a dephasing parameter into transport calculations to simulate the effects of the ions and other fluctuations. These effects lower the overall magnitude of the current, but have little effect on the current distributions themselves. The results of this work further implicate that distinguishing DNA bases via transverse electronic transport has potential as a sequencing tool.
Parton transverse momentum and orbital angular momentum distributions
NASA Astrophysics Data System (ADS)
Rajan, Abha; Courtoy, Aurore; Engelhardt, Michael; Liuti, Simonetta
2016-08-01
The quark orbital angular momentum component of proton spin, Lq, can be defined in QCD as the integral of a Wigner phase space distribution weighting the cross product of the quark's transverse position and momentum. It can also be independently defined from the operator product expansion for the off-forward Compton amplitude in terms of a twist-three generalized parton distribution. We provide an explicit link between the two definitions, connecting them through their dependence on partonic intrinsic transverse momentum. Connecting the definitions provides the key for correlating direct experimental determinations of Lq and evaluations through lattice QCD calculations. The direct observation of quark orbital angular momentum does not require transverse spin polarization but can occur using longitudinally polarized targets.
Quark-jet model for transverse momentum dependent fragmentation functions
NASA Astrophysics Data System (ADS)
Bentz, W.; Kotzinian, A.; Matevosyan, H. H.; Ninomiya, Y.; Thomas, A. W.; Yazaki, K.
2016-08-01
In order to describe the hadronization of polarized quarks, we discuss an extension of the quark-jet model to transverse momentum dependent fragmentation functions. The description is based on a product ansatz, where each factor in the product represents one of the transverse momentum dependent splitting functions, which can be calculated by using effective quark theories. The resulting integral equations and sum rules are discussed in detail for the case of inclusive pion production. In particular, we demonstrate that the three-dimensional momentum sum rules are satisfied naturally in this transverse momentum dependent quark-jet model. Our results are well suited for numerical calculations in effective quark theories and can be implemented in Monte Carlo simulations of polarized quark hadronization processes.
Propagation of a transverse wave on a foam microchannel
NASA Astrophysics Data System (ADS)
Derec, C.; Leroy, V.; Kaurin, D.; Arbogast, L.; Gay, C.; Elias, F.
2015-11-01
In a dry foam, soap films meet by three in the liquid microchannels, called Plateau borders, which contain most of the liquid of the foam. We investigated here the transverse vibration of a single Plateau border isolated on a rigid frame. We measured and we computed numerically and analytically the propagation of a transverse pulse along the channel in the 20-2000 Hz frequency range. The dispersion relation shows different scaling regimes, which provide information on the role of inertial and elastic forces acting on the Plateau border. At low frequency, the dispersion relation is dominated by the vibration of the air set into motion by the transverse vibration of the adjacent soap films. The inertia of the liquid in the Plateau border plays a role at high frequency, the critical frequency separating the low-frequency and the high-frequency regimes being a decreasing function of the radius R of the Plateau border.
Correlation of transverse relaxation time with structure of biological tissue
NASA Astrophysics Data System (ADS)
Furman, Gregory B.; Meerovich, Victor M.; Sokolovsky, Vladimir L.
2016-09-01
Transverse spin-spin relaxation of liquids entrapped in nanocavities with different orientational order is theoretically investigated. Based on the bivariate normal distribution of nanocavities directions, we have calculated the anisotropy of the transverse relaxation time for biological systems, such as collagenous tissues, articular cartilage, and tendon. In the framework of the considered model, the dipole-dipole interaction is determined by a single coupling constant. The calculation results for the transverse relaxation time explain the angular dependence observed in MRI experiments with biological objects. The good agreement with the experimental data is obtained by adjustment of only one parameter which characterizes the disorder in fiber orientations. The relaxation time is correlated with the degree of ordering in biological tissues. Thus, microstructure of the tissues can be revealed from the measurement of relaxation time anisotropy. The clinical significance of the correlation, especially in the detection of damage must be evaluated in a large prospective clinical trials.
An endochronic theory for transversely isotropic fibrous composites
NASA Technical Reports Server (NTRS)
Pindera, M. J.; Herakovich, C. T.
1981-01-01
A rational methodology of modelling both nonlinear and elastic dissipative response of transversely isotropic fibrous composites is developed and illustrated with the aid of the observed response of graphite-polyimide off-axis coupons. The methodology is based on the internal variable formalism employed within the text of classical irreversible thermodynamics and entails extension of Valanis' endochronic theory to transversely isotropic media. Applicability of the theory to prediction of various response characteristics of fibrous composites is illustrated by accurately modelling such often observed phenomena as: stiffening reversible behavior along fiber direction; dissipative response in shear and transverse tension characterized by power-laws with different hardening exponents; permanent strain accumulation; nonlinear unloading and reloading; and stress-interaction effects.
FLUCTUATION AND LOW TRANSVERSE MOMENTUM CORRELATION RESULTS FROM PHENIX.
MITCHELL,J.T.
2006-07-03
The PHENIX Experiment at the Relativistic Heavy Ion Collider has conducted a survey of fluctuations in charged hadron multiplicity in Au+Au and Cu+Cu collisions at {radical}s{sub NN} = 22, 62, and 200 GeV. A universal power law scaling for multiplicity fluctuations expressed as {sigma}{sup 2}/{mu}{sup 2} is observed as a function of N{sub part} for all species studied that is independent of the transverse momentum range of the measurement. PHENIX has also measured transverse momentum correlation amplitudes in p+p, d+Au, and Au+Au collisions. At low transverse momentum, significant differences in the correlations between the baseline p+p and d+Au data and the Au+Au data are presented.
Transverse-longitudinal coupling by space charge in cyclotrons
NASA Astrophysics Data System (ADS)
Baumgarten, C.
2011-11-01
A method is presented that enables one to compute the parameters of matched beams with space charge in cyclotrons with emphasis on the effect of the transverse-longitudinal coupling. Equations describing the transverse-longitudinal coupling and corresponding tune shifts in first order are derived for the model of an azimuthally symmetric cyclotron. The eigenellipsoid of the beam is calculated and the transfer matrix is transformed into block-diagonal form. The influence of the slope of the phase curve on the transverse-longitudinal coupling is accounted for. The results are generalized and numerical procedures for the case of an azimuthally varying field cyclotron are presented. The algorithm is applied to the PSI injector II and ring cyclotron and the results are compared to TRANSPORT.
Effects of transverse beam size in beam position monitors.
Kurennoy, S.
2001-01-01
The fields produced by a long beam with a given transverse charge distribution in a homogeneous vacuum chamber are studied. Signals induced by the displaced finite-size beam on electrodes of a beam position monitor (BPM) are calculated and compared to those from a pencil beam. The non-linearities and corrections to BPM signals due to a finite transverse beam size are calculated for an arbitrary chamber cross section. Simple analytical expressions are given for a few particular transverse distributions of the beam current in a circular or rectangular chamber. Of particular interest is a general proof that in an arbitrary homogeneous chamber the beam-size corrections vanish for any axisymmetric beam current distribution.
Hot electrons transverse refluxing in ultraintense laser-solid interactions.
Buffechoux, S; Psikal, J; Nakatsutsumi, M; Romagnani, L; Andreev, A; Zeil, K; Amin, M; Antici, P; Burris-Mog, T; Compant-La-Fontaine, A; d'Humières, E; Fourmaux, S; Gaillard, S; Gobet, F; Hannachi, F; Kraft, S; Mancic, A; Plaisir, C; Sarri, G; Tarisien, M; Toncian, T; Schramm, U; Tampo, M; Audebert, P; Willi, O; Cowan, T E; Pépin, H; Tikhonchuk, V; Borghesi, M; Fuchs, J
2010-07-01
We have analyzed the coupling of ultraintense lasers (at ∼2×10{19} W/cm{2}) with solid foils of limited transverse extent (∼10 s of μm) by monitoring the electrons and ions emitted from the target. We observe that reducing the target surface area allows electrons at the target surface to be reflected from the target edges during or shortly after the laser pulse. This transverse refluxing can maintain a hotter, denser and more homogeneous electron sheath around the target for a longer time. Consequently, when transverse refluxing takes places within the acceleration time of associated ions, we observe increased maximum proton energies (up to threefold), increased laser-to-ion conversion efficiency (up to a factor 30), and reduced divergence which bodes well for a number of applications. PMID:20867457
Transverse single-spin asymmetries: Challenges and recent progress
Metz, Andreas; Pitonyak, Daniel; Schafer, Andreas; Schlegel, Marc; Vogelsang, Werner; Zhou, Jian
2014-11-25
In this study, transverse single-spin asymmetries are among the most intriguing observables in hadronic physics. Though such asymmetries were already measured for the first time about four decades ago, their origin is still under debate. Here we consider transverse single-spin asymmetries in semi-inclusive lepton–nucleon scattering, in nucleon–nucleon scattering, and in inclusive lepton–nucleon scattering. It is argued that, according to recent work, the single-spin asymmetries for those three processes may be simultaneously described in perturbative QCD, where the re-scattering of the active partons plays a crucial role. A comparison of single-spin asymmetries in different reactions can also shed light on the universality of transverse momentum dependent parton correlation functions. In particular, we discuss what existing data may tell us about the predicted process dependence of the Sivers function.
Transverse single-spin asymmetries: Challenges and recent progress
Metz, Andreas; Pitonyak, Daniel; Schafer, Andreas; Schlegel, Marc; Vogelsang, Werner; Zhou, Jian
2014-11-25
In this study, transverse single-spin asymmetries are among the most intriguing observables in hadronic physics. Though such asymmetries were already measured for the first time about four decades ago, their origin is still under debate. Here we consider transverse single-spin asymmetries in semi-inclusive lepton–nucleon scattering, in nucleon–nucleon scattering, and in inclusive lepton–nucleon scattering. It is argued that, according to recent work, the single-spin asymmetries for those three processes may be simultaneously described in perturbative QCD, where the re-scattering of the active partons plays a crucial role. A comparison of single-spin asymmetries in different reactions can also shed light on themore » universality of transverse momentum dependent parton correlation functions. In particular, we discuss what existing data may tell us about the predicted process dependence of the Sivers function.« less
Transverse current fluctuations in the Yukawa one-component plasma.
Mithen, James P
2014-01-01
Using numerical simulations, we investigate the wave number and frequency dependent transverse current correlation function CT(k,ω) of a single-component fluid with Yukawa interaction potential, also known as the Yukawa one-component plasma. The transverse current correlation function is an important quantity because it contains the microscopic details of the viscoelastic behavior of the fluid. We show that, in the region of densities and temperatures in which shear waves do not propagate, the dynamics of the system are in striking agreement with a simple model of generalized hydrodynamics. As either the density is increased or the temperature decreased, the transverse current correlation function shows additional structure that the simple models fail to capture.
Kinetic theory for electrostatic waves due to transverse velocity shears
NASA Technical Reports Server (NTRS)
Ganguli, G.; Lee, Y. C.; Palmadesso, P. J.
1988-01-01
A kinetic theory in the form of an integral equation is provided to study the electrostatic oscillations in a collisionless plasma immersed in a uniform magnetic field and a nonuniform transverse electric field. In the low temperature limit the dispersion differential equation is recovered for the transverse Kelvin-Helmholtz modes for arbitrary values of K parallel, where K parallel is the component of the wave vector in the direction of the external magnetic field assumed in the z direction. For higher temperatures the ion-cyclotron-like modes described earlier in the literature by Ganguli, Lee and Plamadesso are recovered. In this article, the integral equation is reduced to a second-order differential equation and a study is made of the kinetic Kelvin-Helmholtz and ion-cyclotron-like modes that constitute the two branches of oscillation in a magnetized plasma including a transverse inhomogeneous dc electric field.
Generation of self-healing and transverse accelerating optical vortices
NASA Astrophysics Data System (ADS)
Wei, Bing-Yan; Chen, Peng; Ge, Shi-Jun; Duan, Wei; Hu, Wei; Lu, Yan-Qing
2016-09-01
Self-healing and transverse accelerating optical vortices are generated via modulating Gaussian beams through subsequent liquid crystal q-plate and polarization Airy mask. We analyze the propagation dynamics of these vortex Airy beams, and find that they possess the features of both optical vortices and Airy beams. Topological charges and characteristics of nondiffraction, self-healing, and transverse acceleration are experimentally verified. In addition, vortex Airy beams with both topological charge and radial index are demonstrated and mode switch among Gaussian, vortex, vector, Airy beams and their combinations can be acquired easily. Our design provides a flexible and highly efficient way to generate unique optical vortices with self-healing and transverse acceleration properties, and facilitates prospective applications in optics and photonics.
In Vitro Study of Transverse Strength of Fiber Reinforced Composites
Mosharraf, R.; Hashemi, Z.; Torkan, S.
2011-01-01
Objective Reinforcement with fiber is an effective method for considerable improvement in flexural properties of indirect composite resin restorations. The aim of this in-vitro study was to compare the transverse strength of composite resin bars reinforced with pre-impregnated and non-impregnated fibers. Materials and Methods Thirty six bar type composite resin specimens (3×2×25 mm) were constructed in three groups. The first group was the control group (C) without any fiber reinforcement. The specimens in the second group (P) were reinforced with pre-impregnated fibers and the third group (N) with non-impregnated fibers. These specimens were tested by the three-point bending method to measure primary transverse strength. Data were statistically analyzed with one way ANOVA and Tukey’s tests. Results There was a significant difference among the mean primary transverse strength in the three groups (P<0.001). The post-hoc (Tukey) test showed that there was a significant difference between the pre-impregnated and control groups in their primary transverse strength (P<0.001). Regarding deflection, there was also a significant difference among the three groups (P=0.001). There were significant differences among the mean deflection of the control group and two other groups (PC&N<.001 and PC&P=.004), but there was no significant difference between the non-and pre-impregnated groups (PN&P=.813). Conclusion Within the limitations of this study, it was concluded that reinforcement with fiber considerably increased the transverse strength of composite resin specimens, but impregnation of the fiber used implemented no significant difference in the transverse strength of composite resin samples. PMID:22457836
High-Efficiency Absorber for Damping the Transverse Wake Fields
Novokhatski, A.; Seeman, J.; Weathersby, S.; /SLAC
2007-02-28
Transverse wake fields generated by intense beams may propagate long distances in the vacuum chamber and dissipate power in different shielded elements such as bellows, vacuum valves or vacuum pumps. Induced heating in these elements may be high enough to deteriorate vacuum conditions. We have developed a broadband water-cooled bellows-absorber to capture and damp these harmful transverse fields without impacting the longitudinal beam impedance. Experimental results at the PEP-II SLAC B-factory demonstrate high efficiency of this device. This absorber may be useful in other machines like synchrotron light sources or International Linear Collider.
The study of undulator radiation of transversal oscillator
NASA Astrophysics Data System (ADS)
Kotanjyan, A. S.; Saharian, A. A.
2016-07-01
We study the radiation intensity for a charged transversal oscillator moving around a dielectric cylinder. Similar to the case of coaxial circular motion, under certain conditions for the parameters of the trajectory and dielectric cylinder, strong narrow peaks appear in the angular distribution of the radiation intensity in the exterior medium for a given harmonic. Comparing to the case of a uniform coaxial circular motion, for a transversal oscillator new peaks may appear. The oscillations serve as a mechanism for the control of the spectral-angular characteristics of the radiation intensity
Transversal Anderson localization of sound in acoustic waveguide arrays.
Ye, Yangtao; Ke, Manzhu; Feng, Junheng; Wang, Mudi; Qiu, Chunyin; Liu, Zhengyou
2015-04-22
We present designs of one-dimensional acoustic waveguide arrays and investigate wave propagation inside. Under the condition of single identical waveguide mode and weak coupling, the acoustic wave motion in waveguide arrays can be modeled with a discrete mode-coupling theory. The coupling constants can be retrieved from simulations or experiments as the function of neighboring waveguide separations. Sound injected into periodic arrays gives rise to the discrete diffraction, exhibiting ballistic or extended transport in transversal direction. But sound injected into randomized waveguide arrays readily leads to Anderson localization transversally. The experimental results show good agreement with simulations and theoretical predictions.
Transverse Vibrations of Double Bellows Expansion Joint Restrained Against Rotation
Kameswara, Rao C.; Radhakrishna, M.
2002-07-01
The paper presents the results of investigation of transverse vibrations of double bellows expansion joint restrained against rotation on either end. A theoretical model is developed based on the Bernoulli-Euler beam theory and includes added mass of the fluid flowing inside the pipe-bellow-pipe assembly. Neglecting effect of shear, an exact frequency equation is derived for the transverse vibrations of double bellows expansion joint including the effects of end elastic restraints against rotation. Numerical results are presented for an example bellow showing the effects of variation of elastic restraints and internal pressure on the first two modes of vibration. (authors)
High-efficiency absorber for damping transverse wakefields
NASA Astrophysics Data System (ADS)
Novokhatski, A.; Seeman, J.; Weathersby, S.
2007-04-01
Transverse wakefields generated by intense beams may propagate long distances in a vacuum chamber and dissipate power in different shielded elements such as bellows, vacuum valves, or vacuum pumps. Induced heating in these elements may be high enough to deteriorate vacuum conditions. We have developed a broadband water-cooled bellows absorber to capture and damp these harmful transverse fields without impacting the longitudinal beam impedance. Experimental results at the PEP-II SLAC B-factory demonstrate a high efficiency for this device. This absorber may be useful in super B-factories, the International Linear Collider, the Large Hadron Collider, or synchrotron light sources.
A Monolithic Oxide-Based Transversal Thermoelectric Energy Harvester
NASA Astrophysics Data System (ADS)
Teichert, S.; Bochmann, A.; Reimann, T.; Schulz, T.; Dreßler, C.; Udich, S.; Töpfer, J.
2016-03-01
We report the fabrication and properties of a monolithic transversal thermoelectric energy harvester based on the combination of a thermoelectric oxide and a metal. The fabrication of the device is done with a ceramic multilayer technology using printing and co-firing processes. Five transversal devices were combined to a meander-like thermoelectric generator. Electrical measurements and finite element calculations were performed to characterize the resulting thermoelectric generator. A maximum experimental electrical power output of 30.2 mW at a temperature difference of {Δ }T = 208 K was found. The prepared monolithic thermoelectric generator provides at {Δ }T = 35 K sufficient energy to drive a simple electronic sensor application.
Transverse Momentum-Dependent Parton Distributions From Lattice QCD
Michael Engelhardt, Bernhard Musch, Philipp Haegler, Andreas Schaefer
2012-12-01
Starting from a definition of transverse momentum-dependent parton distributions for semi-inclusive deep inelastic scattering and the Drell-Yan process, given in terms of matrix elements of a quark bilocal operator containing a staple-shaped Wilson connection, a scheme to determine such observables in lattice QCD is developed and explored. Parametrizing the aforementioned matrix elements in terms of invariant amplitudes permits a simple transformation of the problem to a Lorentz frame suited for the lattice calculation. Results for the Sivers and Boer-Mulders transverse momentum shifts are presented, focusing in particular on their dependence on the staple extent and the Collins-Soper evolution parameter.
Transverse momentum dependence of semi-inclusive pion production
Hamlet Mkrtchyan; Peter Bosted
2007-09-19
Cross sections for semi-inclusive electroproduction of charged pions ($\\pi^{\\pm}$) from both proton and deuteron targets were measured for $0.2<0.5$, $2<4$ GeV$^2$, $0.3<1$, and $P_t^2<0.2$ GeV$^2$. We find the azimuthal dependence to be small and consistent with zero, for $P_t<0.1$ GeV. In the context of a simple fit, the initial transverse momenta of $d$ quarks tends to be larger than for $u$ quarks, while the transverse momentum width of the favored fragmentation function is slightly larger than that of the unfavored function.
Decay of transverse acoustic waves in a pulsed gas laser
Kulkarny, V.A.
1980-11-01
The long-term characteristics of transverse acoustic waves in the cavity of a pulsed gaseous laser were studied by analyzing them in a straight duct configuration with nonlinear techniques used in sonic boom problems. A decaying sawtooth waveform containing a shockwave reverberated in the cavity transverse to the flow direction. In the asymptotic decay, the relative pressure perturbation of the wave varies as the 2/5 power of the product of the relative overpressure from the pulse and the speed of sound in the gas.
New insight on the Sivers transverse momentum dependent distribution function
M. Anselmino, M. Boglione, U. D'Alesio, S. Melis, F. Murgia, A. Prokudin
2011-05-01
Polarised Semi-Inclusive Deep Inelastic Scattering (SIDIS) processes allow to study Transverse Momentum Dependent partonic distributions (TMDs), which reveal a non trivial three dimensional internal structure of the hadrons in momentum space. One of the most representative of the TMDs is the so-called Sivers function that describes the distribution of unpolarized quarks inside a transversely polarized proton. We present a novel extraction of the Sivers distribution functions from the most recent experimental data of HERMES and COMPASS experiments. Using suitable parametrizations, within the TMD factorization scheme, and a simple fitting strategy, we also perform a preliminary exploration of the role of the proton sea quarks.
Nonlinear Interaction of Light with Transversely Moving Medium
NASA Astrophysics Data System (ADS)
Tabiryan, N. V.; Nersisyan, S. R.; Warenghem, M.
1996-10-01
Interaction of a light beam with matter reveals extreme sensitivity to transverse motions. Spatio-temporal delocalization of interaction and diffusive transport of light-induced perturbations is revealed through a new family of diffraction patterns. The response of the medium to the transverse motion of the light enhances near the second order phase transition point. The phenomenon has large application potential for the study of motions that are beyond the power of Doppler-effect-based methods, and suggests fundamental problems about critical processes with nonstationary influences.
Higgs Transverse-Momentum Resummation in Direct Space.
Monni, Pier Francesco; Re, Emanuele; Torrielli, Paolo
2016-06-17
We propose a new approach to the resummation of the transverse-momentum distribution of a high-mass color-singlet system in hadronic collisions. The resummation is performed in momentum space and is free of kinematic singularities at small transverse momentum. We derive a formula accurate at the next-to-next-to-leading-logarithmic level, and present the first matched predictions to next-to-next-to-leading order for Higgs-boson production in gluon fusion at the LHC. This method can be adapted to all observables featuring kinematic cancellations in the infrared region.
Transverse momentum dependent (TMD) parton distribution functions: Status and prospects*
Angeles-Martinez, R.; Bacchetta, A.; Balitsky, Ian I.; Boer, D.; Boglione, M.; Boussarie, R.; Ceccopieri, F. A.; Cherednikov, I. O.; Connor, P.; Echevarria, M. G.; et al
2015-01-01
In this study, we review transverse momentum dependent (TMD) parton distribution functions, their application to topical issues in high-energy physics phenomenology, and their theoretical connections with QCD resummation, evolution and factorization theorems. We illustrate the use of TMDs via examples of multi-scale problems in hadronic collisions. These include transverse momentum qT spectra of Higgs and vector bosons for low qT, and azimuthal correlations in the production of multiple jets associated with heavy bosons at large jet masses. We discuss computational tools for TMDs, and present the application of a new tool, TMDLIB, to parton density fits and parameterizations.
Exploring quark transverse momentum distributions with lattice QCD
Bernhard U. Musch, Philipp Hagler, John W. Negele, Andreas Schafer
2011-05-01
We discuss in detail a method to study transverse momentum dependent parton distribution functions (TMDs) using lattice QCD. To develop the formalism and to obtain first numerical results, we directly implement a bi-local quark-quark operator connected by a straight Wilson line, allowing us to study T-even, "process-independent" TMDs. Beyond results for x-integrated TMDs and quark densities, we present a study of correlations in x and transverse momentum. Our calculations are based on domain wall valence quark propagators by the LHP collaboration calculated on top of gauge configurations provided by MILC with 2+1 flavors of asqtad-improved staggered sea quarks.
Higgs Transverse-Momentum Resummation in Direct Space.
Monni, Pier Francesco; Re, Emanuele; Torrielli, Paolo
2016-06-17
We propose a new approach to the resummation of the transverse-momentum distribution of a high-mass color-singlet system in hadronic collisions. The resummation is performed in momentum space and is free of kinematic singularities at small transverse momentum. We derive a formula accurate at the next-to-next-to-leading-logarithmic level, and present the first matched predictions to next-to-next-to-leading order for Higgs-boson production in gluon fusion at the LHC. This method can be adapted to all observables featuring kinematic cancellations in the infrared region. PMID:27367384
Transverse Beam Size Effects in Beam Position Monitors
NASA Astrophysics Data System (ADS)
Kurennoy, Sergey
2001-04-01
The fields produced by a long beam with a given transverse charge distribution in a homogeneous vacuum chamber are studied. Signals induced by the displaced finite-size beam on electrodes of a beam position monitor (BPM) are calculated and compared to those from a pencil beam. The corrections to BPM signals due to a finite beam size are found analytically for a few particular transverse distributions of the beam current. The results for fields can also be directly applied for calculating the beam coupling impedances of small discontinuities.
Effect of transverse current on Andreev bound state
Takahashi, Y.; Hashimoto, Y.; Yun, D. H.; Kim, S. W.; Nakamura, T.; Iye, Y.; Katsumoto, S.
2013-12-04
In a superconductor-normal-superconductor (SNS) structure, the effect of transverse current across the normal part on the transport through Andreev bound states (ABSs) has been examined. Here a ballistic InAs two-dimensional electron system (2DES) is used as the N-layer to form ABSs. At the same time the 2DES has strong spin-orbit interaction, hence there should emerge the spin-Hall effect associated with the transverse current. We have observed strong reduction of characteristic oscillation in the conductance versus bias voltage, which may be attributed to spin polarization due to the spin-Hall effect.
Transverse electric surface mode in atomically thin Boron-Nitride.
Merano, Michele
2016-06-01
The spatial confinement and the propagation length of surface waves in a single-layer two-dimensional atomic crystal are analyzed in terms of its surface susceptibility and its surface conductivity. Based on the values of these macroscopic parameters, extracted from experimental observations, it is confirmed that graphene supports a transverse magnetic nonradiating surface mode in the ultraviolet spectral region while a single-layer hexagonal Boron-Nitride is predicted to support a transverse electric nonradiating surface mode in the visible spectrum. This last mode, at a vacuum wavelength of 633 nm, has a spatial confinement of 15 μm and an intensity-propagation distance greater than 2 cm.
Transverse Momentum-Dependent Parton Distributions from Lattice QCD
NASA Astrophysics Data System (ADS)
Engelhardt, M.; Musch, B.; Hägler, P.; Negele, J.; Schäfer, A.
Starting from a definition of transverse momentum-dependent parton distributions for semi-inclusive deep inelastic scattering and the Drell-Yan process, given in terms of matrix elements of a quark bilocal operator containing a staple-shaped Wilson connection, a scheme to determine such observables in lattice QCD is developed and explored. Parametrizing the aforementioned matrix elements in terms of invariant amplitudes permits a simple transformation of the problem to a Lorentz frame suited for the lattice calculation. Results for the Sivers and Boer-Mulders transverse momentum shifts are presented, focusing in particular on their dependence on the staple extent and the Collins-Soper evolution parameter.
Improving transverse resolution of confocal microscopy through spatiotemporal modulation
NASA Astrophysics Data System (ADS)
Wang, Baokai; Zou, Limin; Zhang, Su; Tan, Jiubin
2015-11-01
A new method is proposed in this paper to improve transverse resolution of a confocal microscope. By setting up the model of a confocal microscope system through spatiotemporal modulation with moving gratings or acousto-optical modulation without defocus distance under coherent light illumination and deducing two-dimensional coherent image formula and transfer function, simulation tests are run with or without spatiotemporal modulation to prove the effectiveness of the proposed method. Simulation results indicate the proposed method can be used to improve the transverse resolution of a confocal microscope system.
NASA Astrophysics Data System (ADS)
Li, D. H.; Zhang, X.; Sze, K. Y.; Liu, Y.
2016-10-01
In this paper, the extended layerwise method (XLWM), which was developed for laminated composite beams with multiple delaminations and transverse cracks (Li et al. in Int J Numer Methods Eng 101:407-434, 2015), is extended to laminated composite plates. The strong and weak discontinuous functions along the thickness direction are adopted to simulate multiple delaminations and interlaminar interfaces, respectively, whilst transverse cracks are modeled by the extended finite element method (XFEM). The interaction integral method and maximum circumferential tensile criterion are used to calculate the stress intensity factor (SIF) and crack growth angle, respectively. The XLWM for laminated composite plates can accurately predicts the displacement and stress fields near the crack tips and delamination fronts. The thickness distribution of SIF and thus the crack growth angles in different layers can be obtained. These information cannot be predicted by using other existing shell elements enriched by XFEM. Several numerical examples are studied to demonstrate the capabilities of the XLWM in static response analyses, SIF calculations and crack growth predictions.
NASA Astrophysics Data System (ADS)
Li, D. H.; Zhang, X.; Sze, K. Y.; Liu, Y.
2016-07-01
In this paper, the extended layerwise method (XLWM), which was developed for laminated composite beams with multiple delaminations and transverse cracks (Li et al. in Int J Numer Methods Eng 101:407-434, 2015), is extended to laminated composite plates. The strong and weak discontinuous functions along the thickness direction are adopted to simulate multiple delaminations and interlaminar interfaces, respectively, whilst transverse cracks are modeled by the extended finite element method (XFEM). The interaction integral method and maximum circumferential tensile criterion are used to calculate the stress intensity factor (SIF) and crack growth angle, respectively. The XLWM for laminated composite plates can accurately predicts the displacement and stress fields near the crack tips and delamination fronts. The thickness distribution of SIF and thus the crack growth angles in different layers can be obtained. These information cannot be predicted by using other existing shell elements enriched by XFEM. Several numerical examples are studied to demonstrate the capabilities of the XLWM in static response analyses, SIF calculations and crack growth predictions.
NASA Technical Reports Server (NTRS)
Kahen, K. B.
1986-01-01
The optical properties of III to V binary and ternary compounds and GaAs-Al(x)Ga(1-x)As superlattices are determined by calculating the real and imaginary parts of the transverse dielectric constant. Emphasis is given to determining the influence of different material and superlattice parameters on the values of the index of refraction and absorption coefficient. In order to calculate the optical properties of a material, it is necessary to compute its electronic band structure. This was accomplished by introducing a partition band structure approach based on a combination of the vector k x vector p and nonlocal pseudopotential techniques. The advantages of this approach are that it is accurate, computationally fast, analytical, and flexible. These last two properties enable incorporation of additional effects into the model, such as disorder scattering, which occurs for alloy materials and excitons. Furthermore, the model is easily extended to more complex structures, for example multiple quantum wells and superlattices. The results for the transverse dielectric constant and absorption coefficient of bulk III to V compounds compare well with other one-electron band structure models and the calculations show that for small frequencies, the index of refraction is determined mainly by the contibution of the outer regions of the Brillouin zone.
Incident Shock-Transverse Jet Interactions at Mach 1.9: Effect of Shock Impingement Location
NASA Astrophysics Data System (ADS)
Zare-Behtash, H.; Lo, K. H.; Erdem, E.; Kontis, K.; Lin, J.; Ukai, T.; Obayashi, S.
The scramjet engine is an efficient design for high-speed propulsion, requiring injection of fuel into a supersonic flow in a short amount of time. Due to the nature of the flow numerous shock waves exist within the combustor of a scramjet, significantly altering the flow characteristics and performance of the engine as the flow Mach number or attitude is changed. According to Mai et al. [1] the location of impingement of the incident shock, relative to the fuel injection location, has significant impact on the mixing and flame-holding properties. This emphasises the importance of understanding and hence the need for controlling the dynamic interactions that are created. Of course another fertile area where transverse jet injections are studied for their application is the creation of forces and moments for pitch and attitude control [2, 3].
Intrinsic transverse momentum and dynamical chiral symmetry breaking
Christian Weiss, Peter Schweitzer, Mark Strikman
2013-01-01
We study the effect of QCD vacuum structure on the intrinsic transverse momentum distribution of partons in the nucleon at a low scale. The dynamical breaking of chiral symmetry is caused by non-perturbative interactions at distances of the order rho ~ 0.2 - 0.3 fm, much smaller than the typical nucleon size R ~ 1 fm, resulting in a two-scale picture of nucleon structure. Using an effective dynamical model based on chiral constituent quark degrees of freedom and the 1/N_c expansion (chiral quark-soliton model), we calculate the transverse momentum distribution of quarks and antiquarks at a low scale. The distribution of valence quarks is localized at p_T ~ 1/R. The distribution of flavor-singlet unpolarized sea quarks exhibits a power-like tail extending up to the chiral-symmetry-breaking scale 1/{rho}. A similar tail is present in the flavor-nonsinglet polarized sea. These features are model-independent and represent the imprint of the QCD vacuum on the nucleon's partonic structure. At the level of the nucleon's light-cone wave function, we show that sea quarks partly exist in correlated pairs of transverse size {rho} << R, analogous to short-range NN correlations in nuclei. We discuss the implications of our findings for the transverse momentum distributions in hard scattering processes (semi-inclusive DIS, Drell-Yan pair production) and possible experimental tests of the non-perturbative parton correlations induced by QCD vacuum structure.
Comparing new models of transverse instability with simulations
Blaskiewicz M.
2012-05-20
Recently, Balbekov and Burov have produced an ordinary integro-differential equation that approximates the Vlasov equation for beams with wakefields and large space charge tune shift. The present work compares this model with simulations. In particular, the claim that certain types of transverse wakes cannot lead to mode coupling instabilities is explored.
Laparoscopic Repair of Internal Transmesocolic Hernia of Transverse Colon
Kishiki, Tomokazu; Mori, Toshiyuki; Hashimoto, Yoshikazu; Matsuoka, Hiroyoshi; Abe, Nobutsugu; Masaki, Tadahiko; Sugiyama, Masanori
2015-01-01
Introduction. Internal hernias are often misdiagnosed because of their rarity, with subsequent significant morbidity. Case Presentation. A 61-year-old Japanese man with no history of surgery was referred for intermittent abdominal pain. CT suggested the presence of a transmesocolic internal hernia. The patient underwent a surgical procedure and was diagnosed with transmesocolic internal hernia. We found internal herniation of the small intestine loop through a defect in the transverse mesocolon, without any strangulation of the small intestine. We were able to complete the operation laparoscopically. The patient's postoperative course was uneventful and the patient was discharged on postoperative day 6. Discussion. Transmesocolic hernia of the transverse colon is very rare. Transmesocolic hernia of the sigmoid colon accounts for 60% of all other mesocolic hernias. Paraduodenal hernias are difficult to distinguish from internal mesocolic transverse hernias. We can rule out paraduodenal hernias with CT. Conclusion. The patient underwent a surgical procedure and was diagnosed with transmesocolic internal hernia. We report a case of a transmesocolic hernia of the transverse colon with intestinal obstruction that was diagnosed preoperatively and for which laparoscopic surgery was performed. PMID:26246930
Transverse oscillations in plasma wakefield experiments at FACET
NASA Astrophysics Data System (ADS)
Adli, E.; Lindstrøm, C. A.; Allen, J.; Clarke, C. I.; Frederico, J.; Gessner, S. J.; Green, S. Z.; Hogan, M. J.; Litos, M. D.; White, G. R.; Yakimenko, V.; An, W.; Clayton, C. E.; Marsh, K. A.; Mori, W. B.; Joshi, C.; Vafaei-Najafabadi, N.; Corde, S.; Lu, W.
2016-09-01
We study transverse effects in a plasma wakefield accelerator. Experimental data from FACET with asymmetry in the beam-plasma system is presented. Energy dependent centroid oscillations are observed on the accelerated part of the charge. The experimental results are compared to PIC simulations and theoretical estimates.
On the accuracy and fitting of transversely isotropic material models.
Feng, Yuan; Okamoto, Ruth J; Genin, Guy M; Bayly, Philip V
2016-08-01
Fiber reinforced structures are central to the form and function of biological tissues. Hyperelastic, transversely isotropic material models are used widely in the modeling and simulation of such tissues. Many of the most widely used models involve strain energy functions that include one or both pseudo-invariants (I4 or I5) to incorporate energy stored in the fibers. In a previous study we showed that both of these invariants must be included in the strain energy function if the material model is to reduce correctly to the well-known framework of transversely isotropic linear elasticity in the limit of small deformations. Even with such a model, fitting of parameters is a challenge. Here, by evaluating the relative roles of I4 and I5 in the responses to simple loadings, we identify loading scenarios in which previous models accounting for only one of these invariants can be expected to provide accurate estimation of material response, and identify mechanical tests that have special utility for fitting of transversely isotropic constitutive models. Results provide guidance for fitting of transversely isotropic constitutive models and for interpretation of the predictions of these models.
Multi-particle correlations in transverse momenta from statistical clusters
NASA Astrophysics Data System (ADS)
Bialas, Andrzej; Bzdak, Adam
2016-09-01
We evaluate n-particle (n = 2 , 3 , 4 , 5) transverse momentum correlations for pions and kaons following from the decay of statistical clusters. These correlation functions could provide strong constraints on a possible existence of thermal clusters in the process of particle production.
HICOV - Newton-Raphson calculus of variation with automatic transversalities
NASA Technical Reports Server (NTRS)
Heintschel, T. J.
1968-01-01
Computer program generates trajectories that are optimum with respect to payload placed in an earth orbit. It uses a subroutine package which produces the terminal and transversality conditions and their partial derivatives. This program is written in FORTRAN 4 and FORMAC for the IBM 7094 computer.
Transverse Mode Multi-Resonant Single Crystal Transducer
NASA Technical Reports Server (NTRS)
Snook, Kevin A. (Inventor); Liang, Yu (Inventor); Luo, Jun (Inventor); Hackenberger, Wesley S. (Inventor); Sahul, Raffi (Inventor)
2015-01-01
A transducer is disclosed that includes a multiply resonant composite, the composite having a resonator bar of a piezoelectric single crystal configured in a d(sub 32) transverse length-extensional resonance mode having a crystallographic orientation set such that the thickness axis is in the (110) family and resonance direction is the (001) family.
A Critical Characteristic in the Transverse Galloping Pattern
Wei, Xiaohui; Long, Yongjun; Wang, Chunlei; Wang, Shigang
2015-01-01
Transverse gallop is a common gait used by a large number of quadrupeds. This paper employs the simplified dimensionless quadrupedal model to discuss the underlying mechanism of the transverse galloping pattern. The model is studied at different running speeds and different values of leg stiffness, respectively. If the horizontal running speed reaches up to a critical value at a fixed leg stiffness, or if the leg stiffness reaches up to a critical value at a fixed horizontal speed, a key property would emerge which greatly reduces the overall mechanical forces of the dynamic system in a proper range of initial pitch angular velocities. Besides, for each horizontal speed, there is an optimal stiffness of legs that can reduce both the mechanical loads and the metabolic cost of transport. Furthermore, different body proportions and landing distance lags of a pair of legs are studied in the transverse gallop. We find that quadrupeds with longer length of legs compared with the length of the body are more suitable to employ the transverse galloping pattern, and the landing distance lag of a pair of legs could reduce the cost of transport and the locomotion frequency. PMID:27087773
Transverse Mode Dynamics of VCSELs Undergoing Current Modulation
NASA Technical Reports Server (NTRS)
Goorjian, Peter M.; Ning, C. Z.; Agrawal, Govind
2000-01-01
Transverse mode dynamics of a 20-micron-diameter vertical-cavity surface-emitting laser (VCSEL) undergoing gain switching by deep current modulation is studied numerically. The direct current (dc) level is set slightly below threshold and is modulated by a large alternating current (ac). The resulting optical pulse train and transverse-mode patterns are obtained numerically. The ac frequency is varied from 2.5 GHz to 10 GHz, and the ac amplitude is varied from one-half to four times that of the dc level. At high modulation frequencies, a regular pulse train is not generated unless the ac amplitude is large enough. At all modulation frequencies, the transverse spatial profile switches from single-mode to multiple-mode pattern as the ac pumping level is increased. Optical pulse widths vary in the range 5-30 ps. with the pulse width decreasing when either the frequency is increased or the ac amplitude is decreased. The numerical modeling uses an approximation form of the semiconductor Maxwell-Bloch equations. Temporal evolution of the spatial profiles of the laser (and of carrier density) is determined without any assumptions about the type or number of modes. Keywords: VCSELs, current modulation, gain switching, transverse mode dynamics, computational modeling
Quantitative transverse flow measurement using OCT speckle decorrelation analysis
Liu, Xuan; Huang, Yong; Ramella-Roman, Jessica C.; Mathews, Scott A.; Kang, Jin U.
2014-01-01
We propose an inter-Ascan speckle decorrelation based method that can quantitatively assess blood flow normal to the direction of the OCT imaging beam. To validate this method, we performed a systematic study using both phantom and in vivo animal models. Results show that our speckle analysis method can accurately extract transverse flow speed with high spatial and temporal resolution. PMID:23455305
On the polarization of non-paraxial transverse fields
NASA Astrophysics Data System (ADS)
Martínez-Herrero, Rosario; Moreu, Andrés Ferrer
2006-11-01
On the basis of a plane-wave spectrum representation, the polarization features of a transverse quasimonochromatic non-paraxial field have been studied. A relationship has been established between the polarization characteristics in the near field and the coherence and symmetry properties of the beam in the far field.
Transverse momentum distributions of jets and weak bosons
Ellis, R.K.
1984-05-01
The theoretical description of processes leading to events at large transverse momentum is reviewed. Numerical estimates are given for jet cross-sections and for W and Z production cross-sections. The influence which uncertainties in the input parameters have on the theoretical predictions is also discussed.
Transverse momentum dependent quark densities from Lattice QCD
Bernhard Musch,Philipp Hagler,John Negele,Andreas Schafer
2011-10-01
We study transverse momentum dependent parton distribution functions (TMDs) with non-local operators in lattice QCD, using MILC/LHPC lattices. We discuss the basic concepts of the method, including renormalization of the gauge link. Results obtained with a simplified operator geometry show visible dipole deformations of spin-dependent quark momentum densities.
Using transverse isotropy to model arbitrary deformation-induced anisotropy
Brannon, R.M.
1996-07-01
A unifying framework is developed for the analysis of brittle materials. Heretofore diverse classes of models result from different choices for unspecified coefficient and distribution functions in the unified theory. Material response is described in terms of expectation integrals of transverse symmetry tensors. First, a canonical body containing cracks of all the same orientation is argued to possess macroscopic transverse isotropy. An orthogonal basis for the linear subspace consisting of all double-symmetric transversely-isotropic fourth-order tensors associated with a given material vector is introduced and applied to deduce the explicit functional dependence of the compliance of such contrived materials on the shared crack orientation. A principle of superposition of strain rates is used to write the compliance for a more realistic material consisting of cracks of random size and orientation as an expectation integral of the transverse compliance for each orientation times the joint distribution function for the size and orientation. Utilizing an evolving (initially exponential) size- dependence in the joint distribution, the general theory gives unprecedented agreement with measurements of the dynamic response of alumina to impact loading, especially upon release where the calculations predict the development of considerable deformation- induced anisotropy, challenging the conventional notion of shocks as isotropic phenomena.
TRANSVERSE BEAM TRANSFER FUNCTIONS OF COLLIDING BEAMS IN RHIC
FISCHER,W.; BLASKIEWICZ, M.; CALAGA, R.; CAMERON, P.; HERR, W.; PIELONI, T.
2007-06-25
We use transverse beam transfer functions to measure tune distributions of colliding beams in RHIC. The tune has a distribution due to the beam-beam interaction, nonlinear magnetic fields -- particularly in the interaction region magnets, and non-zero chromaticity in conjunction with momentum spread. The measured tune distributions are compared with calculations.
A Simple Laser Teaching Aid for Transverse Mode Structure Demonstration
ERIC Educational Resources Information Center
Ren, Cheng; Zhang, Shulian
2009-01-01
A teaching aid for demonstrating the transverse mode structure in lasers is described. A novel device called "multi-dimension adjustable combined cat-eye reflector" has been constructed from easily available materials to form a He-Ne laser resonator. By finely adjusting the cat-eye, the boundary conditions of the laser cavity can be altered, which…
A STATISTICAL STUDY OF TRANSVERSE OSCILLATIONS IN A QUIESCENT PROMINENCE
Hillier, A.; Morton, R. J.; Erdélyi, R.
2013-12-20
The launch of the Hinode satellite has allowed for seeing-free observations at high-resolution and high-cadence making it well suited to study the dynamics of quiescent prominences. In recent years it has become clear that quiescent prominences support small-amplitude transverse oscillations, however, sample sizes are usually too small for general conclusions to be drawn. We remedy this by providing a statistical study of transverse oscillations in vertical prominence threads. Over a 4 hr period of observations it was possible to measure the properties of 3436 waves, finding periods from 50 to 6000 s with typical velocity amplitudes ranging between 0.2 and 23 km s{sup –1}. The large number of observed waves allows the determination of the frequency dependence of the wave properties and derivation of the velocity power spectrum for the transverse waves. For frequencies less than 7 mHz, the frequency dependence of the velocity power is consistent with the velocity power spectra generated from observations of the horizontal motions of magnetic elements in the photosphere, suggesting that the prominence transverse waves are driven by photospheric motions. However, at higher frequencies the two distributions significantly diverge, with relatively more power found at higher frequencies in the prominence oscillations. These results highlight that waves over a large frequency range are ubiquitous in prominences, and that a significant amount of the wave energy is found at higher frequency.
Piezoelectric energy harvesting from transverse galloping of bluff bodies
NASA Astrophysics Data System (ADS)
Abdelkefi, A.; Hajj, M. R.; Nayfeh, A. H.
2013-01-01
The concept of harvesting energy from transverse galloping oscillations of a bluff body with different cross-section geometries is investigated. The energy is harvested by attaching a piezoelectric transducer to the transverse degree of freedom of the body. The power levels that can be generated from these vibrations and the variations of these levels with the load resistance, cross-section geometry, and freestream velocity are determined. A representative model that accounts for the transverse displacement of the bluff body and harvested voltage is presented. The quasi-steady approximation is used to model the aerodynamic loads. A linear analysis is performed to determine the effects of the electrical load resistance and the cross-section geometry on the onset of galloping, which is due to a Hopf bifurcation. The normal form of this bifurcation is derived to determine the type (supercritical or subcritical) of the instability and to characterize the effects of the linear and nonlinear parameters on the level of harvested power near the bifurcation. The results show that the electrical load resistance and the cross-section geometry affect the onset speed of galloping. The results also show that the maximum levels of harvested power are accompanied with minimum transverse displacement amplitudes for all considered (square, D, and triangular) cross-section geometries, which points to the need for performing a coupled analysis of the system.
NASA Astrophysics Data System (ADS)
Sun, Fadi; Ye, Jinwu; Liu, Wu-Ming
2016-07-01
In this paper, we study the rotated ferromagnetic Heisenberg model (RFHM) in two different transverse fields, hx and hz, which can be intuitively visualized as studying spin-orbit coupling (SOC) effects in two-dimensional (2D) Ising or anisotropic X Y model in a transverse field. At a special SOC class, it was found in our previous work [Phys. Rev. A 92, 043609 (2015), 10.1103/PhysRevA.92.043609] that the RFHM at a zero field owns an exact spin-orbit coupled ground state called the Y -x state. It supports not only the commensurate magnons (called C -C0 and C -Cπ ), but also the incommensurate magnons (called C-IC). These magnons are nonrelativistic, not embedded in the exact ground state, so need to be thermally excited or generated by various external probes. Their dramatic response under a longitudinal hy field was recently worked out by Sun et al. [arXiv:1502.05338]. Here we find they respond very differently under the two transverse fields. Any hx (hz) introduces quantum fluctuations to the ground state and changes the collinear Y -x state to a canted coplanar Y X -x (Y Z -x ) state. The C -C0,C -Cπ , and C-IC magnons become relativistic and sneak into the quantum ground state. We determine the competing boundaries among the C -C0,C -Cπ , and C-IC magnons, especially the detailed dispersions of the C-IC magnons inside the canted phases, which can be mapped out by the transverse spin structure factors. As hx (hz) increases further, the C -C0 magnons always win the competition and emerge as the seeds to drive a transition from the Y X -x (or Y Z -x ) to the ferromagnetic along the X (orZ ) direction called the X -FM (or Z -FM) phase. We show that the transition is in the 3D Ising universality class and it becomes the 3D X Y transition at the two Abelian points. We evaluate these magnons' contributions to magnetization and specific heat at low temperatures which can be measured by various established experimental techniques. The nature of the finite
The transverse mechanical behaviour of glass fibre reinforced plastics
NASA Astrophysics Data System (ADS)
Wells, Garry Michael
The importance of transverse cracking in composites technology is highlighted by the use of classical lamination theory to predict the sequential damage process in cross-plied laminates. The literature on transverse fibre carposite behaviour is comprehensively reviewed, with particular emphasis on papers which present quantitative theoretical models. No work reviewed has measured the full range of mechanical properties on a single material necessary to allow a complete assessment of all the models of transverse failure. A resin system, based on epoxy/urethane blends, has been identified which allows production of high quality unidirectional composites with a systematic variation in flexibility. A preliminary experimental programme has identified those test specimens which can provide the necessary stress/strain and toughness properties of the range of flexibilised materials and thereby allow a validation of the theoretical models reviewed. In the preliminary experimental programme, transverse cracks are shown to extend with an increasing fracture toughness due to the formation of a 'tied zone' of fracture face bridging 'stringers' behind the crack tip. The influence of this effect on crack stability is discussed. By modelling the balance between fracture and strain energies, the equilibrium state of individual stringers is predicted. Direct observations of equilibrium stringer angles are seen to correspond with these predictions. A quite general model is developed which predicts, with reasonble accuracy, the observed increase of fracture toughness with crack extension and the geometry dependence of this increase. The literature models of stiffness, strength and failure strain are seen to display a dissappointing lack of agreement with the experimental results over the full range of material flexibilities. The influence of matrix Poisson constraint on these properties is discussed. Fracture toughness results indicate that very large critical defects control
Awad, Amer; Stüve, Olaf
2011-01-01
Transverse myelitis is a focal inflammatory disorder of the spinal cord which may arise due to different etiologies. Transverse myelitis may be idiopathic or related/secondary to other diseases including infections, connective tissue disorders and other autoimmune diseases. It may be also associated with optic neuritis (neuromyelitis optica), which may precede transverse myelitis. In this manuscript we review the pathophysiology of different types of transverse myelitis and neuromyelitis optica and discuss diagnostic criteria for idiopathic transverse myelitis and risk of development of multiple sclerosis after an episode of transverse myelitis. We also discuss treatment options including corticosteroids, immunosuppressives and monoclonal antibodies, plasma exchange and intravenous immunoglobulins. PMID:22379456
Stimulated emission and optical gain in AlGaN heterostructures grown on bulk AlN substrates
Guo, Wei Bryan, Zachary; Kirste, Ronny; Bryan, Isaac; Hussey, Lindsay; Bobea, Milena; Haidet, Brian; Collazo, Ramón; Sitar, Zlatko; Xie, Jinqiao; Mita, Seiji; Gerhold, Michael
2014-03-14
Optical gain spectra for ∼250 nm stimulated emission were compared in three different AlGaN-based structures grown on single crystalline AlN substrates: a single AlGaN film, a double heterostructure (DH), and a Multiple Quantum Well (MQW) structure; respective threshold pumping power densities of 700, 250, and 150 kW/cm{sup 2} were observed. Above threshold, the emission was transverse-electric polarized and as narrow as 1.8 nm without a cavity. The DH and MQW structures showed gain values of 50–60 cm{sup −1} when pumped at 1 MW/cm{sup 2}. The results demonstrated the excellent optical quality of the AlGaN-based heterostructures grown on AlN substrates and their potential for realizing electrically pumped sub-280 nm laser diodes.
A Novel Transverse Flux Machine for Vehicle Traction Applications
Wan, Zhao; Ahmed, Adeeb; Husain, Iqbal; Muljadi, Eduard
2015-10-05
A novel transverse flux machine topology for electric vehicle traction application using ferrite magnets is presented in this paper. The proposed transverse flux topology utilizes novel magnet arrangements in the rotor that are similar to Halbach-array to boost flux linkage; on the stator side, cores are alternately arranged around a pair of ring windings in each phase to make use of the entire rotor flux that eliminates end windings. Analytical design considerations and finite element methods are used for an optimized design of a scooter in-wheel motor. Simulation results from Finite Element Analysis (FEA) show the motor achieved comparable torque density to conventional rare-earth permanent magnet machines. This machine is a viable candidate for direct drive applications with low cost and high torque density.
Calculation of TMD Evolution for Transverse Single Spin Asymmetry Measurements
Mert Aybat, Ted Rogers, Alexey Prokudin
2012-06-01
In this letter, we show that it is necessary to include the full treatment of QCD evolution of Transverse Momentum Dependent parton densities to explain discrepancies between HERMES data and recent COMPASS data on a proton target for the Sivers transverse single spin asymmetry in Semi-Inclusive Deep Inelastic Scattering (SIDIS). Calculations based on existing fits to TMDs in SIDIS, and including evolution within the Collins-Soper-Sterman with properly defined TMD PDFs are shown to provide a good explanation for the discrepancy. The non-perturbative input needed for the implementation of evolution is taken from earlier analyses of unpolarized Drell-Yan (DY) scattering at high energy. Its success in describing the Sivers function in SIDIS data at much lower energies is strong evidence in support of the unifying aspect of the QCD TMD-factorization formalism.
Stress waves in transversely isotropic media: The homogeneous problem
NASA Technical Reports Server (NTRS)
Marques, E. R. C.; Williams, J. H., Jr.
1986-01-01
The homogeneous problem of stress wave propagation in unbounded transversely isotropic media is analyzed. By adopting plane wave solutions, the conditions for the existence of the solution are established in terms of phase velocities and directions of particle displacements. Dispersion relations and group velocities are derived from the phase velocity expressions. The deviation angles (e.g., angles between the normals to the adopted plane waves and the actual directions of their propagation) are numerically determined for a specific fiber-glass epoxy composite. A graphical method is introduced for the construction of the wave surfaces using magnitudes of phase velocities and deviation angles. The results for the case of isotropic media are shown to be contained in the solutions for the transversely isotropic media.
Suppression of microbunching instability via a transverse gradient undulator
NASA Astrophysics Data System (ADS)
Feng, Chao; Huang, Dazhang; Deng, Haixiao; Gu, Qiang; Zhao, Zhentang
2015-07-01
The microbunching instability in the linear accelerator (linac) of a free-electron laser facility has always been a problem that degrades the electron beam quality. In this paper, a quite simple and inexpensive technique is proposed to smooth the electron beam current profile to suppress the instability. By directly adding a short undulator with a transverse gradient field right after the injector to couple the transverse spread into the longitudinal direction, additional density mixing in the electron beam is introduced to smooth the current profile, which results in the reduction of the gain of the microbunching instability. The magnitude of the density mixing can be easily controlled by varying the strength of the undulator magnetic field. Theoretical analysis and numerical simulations demonstrate the capability of the proposed technique in the accelerator of an x-ray free-electron laser.
Proper definition and evolution of generalized transverse momentum dependent distributions
NASA Astrophysics Data System (ADS)
Echevarria, Miguel G.; Idilbi, Ahmad; Kanazawa, Koichi; Lorcé, Cédric; Metz, Andreas; Pasquini, Barbara; Schlegel, Marc
2016-08-01
We consider one of the most fundamental sets of hadronic matrix elements, namely the generalized transverse momentum dependent distributions (GTMDs), and argue that their existing definitions lack proper evolution properties. By exploiting the similarity of GTMDs with the much better understood transverse momentum distributions, we argue that the existing definitions of GTMDs have to include an additional dependence on soft gluon radiation in order to render them properly defined. With this, we manage to obtain the evolution kernel of all (un)polarized quark and gluon GTMDs, which turns out to be spin independent. As a byproduct, all large logarithms can be resummed up to next-to-next-to-leading-logarithmic accuracy with the currently known perturbative ingredients.
Transverse electric surface mode in atomically thin Boron-Nitride.
Merano, Michele
2016-06-01
The spatial confinement and the propagation length of surface waves in a single-layer two-dimensional atomic crystal are analyzed in terms of its surface susceptibility and its surface conductivity. Based on the values of these macroscopic parameters, extracted from experimental observations, it is confirmed that graphene supports a transverse magnetic nonradiating surface mode in the ultraviolet spectral region while a single-layer hexagonal Boron-Nitride is predicted to support a transverse electric nonradiating surface mode in the visible spectrum. This last mode, at a vacuum wavelength of 633 nm, has a spatial confinement of 15 μm and an intensity-propagation distance greater than 2 cm. PMID:27244441
Electrical modulation and switching of transverse acoustic phonons
NASA Astrophysics Data System (ADS)
Jeong, H.; Jho, Y. D.; Rhim, S. H.; Yee, K. J.; Yoon, S. Y.; Shim, J. P.; Lee, D. S.; Ju, J. W.; Baek, J. H.; Stanton, C. J.
2016-07-01
We report on the electrical manipulation of coherent acoustic phonon waves in GaN-based nanoscale piezoelectric heterostructures which are strained both from the pseudomorphic growth at the interfaces as well as through external electric fields. In such structures, transverse symmetry within the c plane hinders both the generation and detection of the transverse acoustic (TA) modes, and usually only longitudinal acoustic phonons are generated by ultrafast displacive screening of potential gradients. We show that even for c -GaN, the combined application of lateral and vertical electric fields can not only switch on the normally forbidden TA mode, but they can also modulate the amplitudes and frequencies of both modes. By comparing the transient differential reflectivity spectra in structures with and without an asymmetric potential distribution, the role of the electrical controllability of phonons was demonstrated as changes to the propagation velocities, the optical birefringence, the electrically polarized TA waves, and the geometrically varying optical sensitivities of phonons.
Transverse coupling property of beam from ECR ion sources
Yang, Y.; Yuan, Y. J.; Sun, L. T.; Feng, Y. C.; Fang, X.; Cao, Y.; Lu, W.; Zhang, X. Z.; Zhao, H. W.
2014-11-15
Experimental evidence of the property of transverse coupling of beam from Electron Cyclotron Resonance (ECR) ion source is presented. It is especially of interest for an ECR ion source, where the cross section of extracted beam is not round along transport path due to the magnetic confinement configuration. When the ions are extracted and accelerated through the descending axial magnetic field at the extraction region, the horizontal and vertical phase space strongly coupled. In this study, the coupling configuration between the transverse phase spaces of the beam from ECR ion source is achieved by beam back-tracking simulation based on the measurements. The reasonability of this coupling configuration has been proven by a series of subsequent simulations.
Universal transversal gates with color codes: A simplified approach
NASA Astrophysics Data System (ADS)
Kubica, Aleksander; Beverland, Michael E.
2015-03-01
We provide a simplified yet rigorous presentation of the ideas from Bombín's paper (arXiv:1311.0879v3). Our presentation is self-contained, and assumes only basic concepts from quantum error correction. We provide an explicit construction of a family of color codes in arbitrary dimensions and describe some of their crucial properties. Within this framework, we explicitly show how to transversally implement the generalized phase gate Rn=diag(1 ,e2 π i /2n) , which deviates from the method in the aforementioned paper, allowing an arguably simpler proof. We describe how to implement the Hadamard gate H fault tolerantly using code switching. In three dimensions, this yields, together with the transversal controlled-not (cnot), a fault-tolerant universal gate set {H ,c n o t ,R3} without state distillation.
Evaluation of electrical transverse conductivity of the unidirectional CFRP
NASA Astrophysics Data System (ADS)
Khebbab, Mohamed; Feliachi, Mouloud; El Hadi Latreche, M.
2016-01-01
In this paper, a technique for the calculation of the electrical transverse conductivity of unidirectional carbon fiber reinforced polymer (CFRP), based on Markov chains, is proposed. Inspired by the microscopic cross-sectional structure of CFRP, an electrical percolation system is constructed. The effective transverse conductivity is derived from an equivalent conductance of the percolation network. To achieve such a determination, a notion of escape probability associated to absorbing Markov chains is applied. The obtained results are compared with those given by percolation theory; and also with published experimental data. Our results are shown to be in good agreement with the references. Contribution to the topical issue "Numelec 2015 - Elected submissions", edited by Adel Razek
Resolution of Transverse Electron Beam Measurements using Optical Transition Radiation
Ischebeck, Rasmus; Decker, Franz-Josef; Hogan, Mark; Iverson, Richard H.; Krejcik, Patrick; Lincoln, Melissa; Siemann, Robert H.; Walz, Dieter; Clayton, Chris E.; Huang, Chengkun; Lu, Wei; Deng, Suzhi; Oz, Erdem; /Southern California U.
2005-06-22
In the plasma wakefield acceleration experiment E-167, optical transition radiation is used to measure the transverse profile of the electron bunches before and after the plasma acceleration. The distribution of the electric field from a single electron does not give a point-like distribution on the detector, but has a certain extension. Additionally, the resolution of the imaging system is affected by aberrations. The transverse profile of the bunch is thus convolved with a point spread function (PSF). Algorithms that deconvolve the image can help to improve the resolution. Imaged test patterns are used to determine the modulation transfer function of the lens. From this, the PSF can be reconstructed. The Lucy-Richardson algorithm is used to deconvolute this PSF from test images.
Transverse momentum-dependent parton distribution functions from lattice QCD
Michael Engelhardt, Philipp Haegler, Bernhard Musch, John Negele, Andreas Schaefer
2012-12-01
Transverse momentum-dependent parton distributions (TMDs) relevant for semi-inclusive deep inelastic scattering (SIDIS) and the Drell-Yan process can be defined in terms of matrix elements of a quark bilocal operator containing a staple-shaped Wilson connection. Starting from such a definition, a scheme to determine TMDs in lattice QCD is developed and explored. Parametrizing the aforementioned matrix elements in terms of invariant amplitudes permits a simple transformation of the problem to a Lorentz frame suited for the lattice calculation. Results for the Sivers and Boer-Mulders transverse momentum shifts are obtained using ensembles at the pion masses 369MeV and 518MeV, focusing in particular on the dependence of these shifts on the staple extent and a Collins-Soper-type evolution parameter quantifying proximity of the staples to the light cone.
Propagation of optical beams in two transverse gradient index media
NASA Astrophysics Data System (ADS)
Martín-Ruiz, A.; Martín-Heredia, J.; Ruiz-Ochoa, L. A.; Chan-López, E.
2016-05-01
We investigate the propagation of optical beams in two gradient index inhomogeneous media. The Green's function for paraxial propagation in an inhomogeneous medium is derived as a Feynman path integral involving summation over real rays. We use a simple method based on discontinuous functions, which is similar to that used in General Relativity when studying metric discontinuities across an hypersurface, to study the propagation in two transverse refractive index gradients which are coupled in the propagation direction. We show that this method is consistent with the geometric-optics ray theory, and then with the definition of the coupled Green's function. The propagation of Gaussian beams in two homogeneous media with different refractive indices is analyzed. We also study the propagation of Airy beams in two media with different linear transverse refractive index gradients. We demonstrate that by controlling the gradient strength of the media it is possible to reduce to zero their acceleration, yielding an Airy beam that propagates linearly.
Nonlinear Accelerator with Transverse Motion Integrable in Normalized Polar Coordinates
Nagaitsev, S.; Kharkov, Y.; Morozov, I.A.; Zolkin, T.V.; /Chicago U.
2012-05-01
Several families of nonlinear accelerator lattices with integrable transverse motion were suggested recently. One of the requirements for the existence of two analytic invariants is a special longitudinal coordinate dependence of fields. This paper presents the particle motion analysis when a problem becomes integrable in the normalized polar coordinates. This case is distinguished from the others: it yields an exact analytical solution and has a uniform longitudinal coordinate dependence of the fields (since the corresponding nonlinear potential is invariant under the transformation from the Cartesian to the normalized coordinates). A number of interesting features are revealed: while the frequency of radial oscillations is independent of the amplitude, the spread of angular frequencies in a beam is absolute. A corresponding spread of frequencies of oscillations in the Cartesian coordinates is evaluated via the simulation of transverse Schottky noise.
Transverse momentum dependent (TMD) parton distribution functions: Status and prospects*
Angeles-Martinez, R.; Bacchetta, A.; Balitsky, Ian I.; Boer, D.; Boglione, M.; Boussarie, R.; Ceccopieri, F. A.; Cherednikov, I. O.; Connor, P.; Echevarria, M. G.; Ferrera, G.; Grados Luyando, J.; Hautmann, F.; Jung, H.; Kasemets, T.; Kutak, K.; Lansberg, J. P.; Lykasov, G.; Madrigal Martinez, J. D.; Mulders, P. J.; Nocera, E. R.; Petreska, E.; Pisano, C.; Placakyte, R.; Radescu, V.; Radici, M.; Schnell, G.; Signori, A.; Szymanowski, L.; Taheri Monfared, S.; Van der Veken, F. F.; van Haevermaet, H. J.; Van Mechelen, P.; Vladimirov, A. A.; Wallon, S.
2015-01-01
In this study, we review transverse momentum dependent (TMD) parton distribution functions, their application to topical issues in high-energy physics phenomenology, and their theoretical connections with QCD resummation, evolution and factorization theorems. We illustrate the use of TMDs via examples of multi-scale problems in hadronic collisions. These include transverse momentum q_{T} spectra of Higgs and vector bosons for low q_{T}, and azimuthal correlations in the production of multiple jets associated with heavy bosons at large jet masses. We discuss computational tools for TMDs, and present the application of a new tool, TMD_{LIB}, to parton density fits and parameterizations.
Principles of transverse flow fractionation of microparticles in superhydrophobic channels.
Asmolov, Evgeny S; Dubov, Alexander L; Nizkaya, Tatiana V; Kuehne, Alexander J C; Vinogradova, Olga I
2015-07-01
We propose a concept of fractionation of micron-sized particles in a microfluidic device with a bottom wall decorated by superhydrophobic stripes. The stripes are oriented at an angle α to the direction of a driving force, G, which generally includes an applied pressure gradient and gravity. Separation relies on the initial sedimentation of particles under gravity in the main forward flow, and their subsequent lateral deflection near a superhydrophobic wall due to generation of a secondary flow transverse to G. We provide some theoretical arguments allowing us to quantify the transverse displacement of particles in the microfluidic channel, and confirm the validity of theoretical predictions in test experiments with monodisperse fractions of microparticles. Our results can guide the design of superhydrophobic microfluidic devices for efficient sorting of microparticles with a relatively small difference in size and density. PMID:26016651
Transverse mixing of simulated piscicides in small montane streams
Brown, Peter J.; Ard, Jenifer L.; Zale, Alexander V.
2012-01-01
Thorough mixing of piscicides into receiving waters is important for efficient and effective fish eradication. However, no guidance exists for the placement of drip stations with respect to mixing. Salt (NaCl) was used as a tracer to measure the mixing rates of center versus edge applications in riffle–pool, straight, and meandering sections of montane streams. The tracer was applied at either the center or the edge of a channel and measured with a conductivity meter across a downstream grid to determine the distances at which transverse mixing was complete. No advantage was accrued by applying piscicides in different types of channels because transverse mixing distance did not differ among them. However, mixing distance was significantly shorter at center applications. Chemicals entering a stream at the center of the channel mixed thoroughly within 10 stream widths, whereas chemicals entering a stream channel at the edge mixed thoroughly within 20 stream widths.
Novel Transverse Flux Machine for Vehicle Traction Applications: Preprint
Wan, Z.; Ahmed, A.; Husain, I.; Muljadi, E.
2015-04-02
A novel transverse flux machine topology for electric vehicle traction applications using ferrite magnets is presented in this paper. The proposed transverse flux topology utilizes novel magnet arrangements in the rotor that are similar to the Halbach array to boost flux linkage; on the stator side, cores are alternately arranged around a pair of ring windings in each phase to make use of the entire rotor flux that eliminates end windings. Analytical design considerations and finite-element methods are used for an optimized design of a scooter in-wheel motor. Simulation results from finite element analysis (FEA) show that the motor achieved comparable torque density to conventional rare-earth permanent magnet (PM) machines. This machine is a viable candidate for direct-drive applications with low cost and high torque density.
GTF Transverse and Longitudinal Emittance Data Analysis Technique
Not Available
2010-12-07
The SSRL Gun Test Facility (GTF) was built to develop a high brightness electron injector for the LCLS and has been operational since 1996. Measurements at the GTF include quadrupole scan transverse emittance measurements and linac phase scan longitudinal emittance measurements. Typically the beam size is measured on a screen as a function of a quadrupole current or linac phase and the beam matrix is then fit to the measured data. Often the emittance which is the final result of the measurement is the only number reported. However, the method used to reduce the data to the final emittance value can have a significant effect on the result. This paper describes in painful detail the methods used to analyze the transverse and longitudinal emittance data collected at the GTF.
Transverse impedance measurement in RHIC and the AGS
Biancacci, Nicolo; Blaskiewicz, M.; Dutheil, Y.; Liu, C.; Mernick, M.; Minty, M.; White, S. M.
2014-05-12
The RHIC luminosity upgrade program aims for an increase of the polarized proton luminosity by a factor 2. To achieve this goal a significant increase in the beam intensity is foreseen. The beam coupling impedance could therefore represent a source of detrimental effects for beam quality and stability at high bunch intensities. For this reason it is essential to quantify the accelerator impedance budget and the major impedance sources, and possibly cure them. In this MD note we summarize the results of the 2013 transverse impedance measurements in the AGS and RHIC. The studies have been performed measuring the tune shift as a function of bunch intensity and deriving the total accelerator machine transverse impedance. For RHIC, we could obtain first promising results of impedance localization measurements as well.
Transverse charge and magnetization densities in the nucleon's chiral periphery
Granados, Carlos G.; Weiss, Christian
2014-01-01
In the light-front description of nucleon structure the electromagnetic form factors are expressed in terms of frame-independent transverse densities of charge and magnetization. Recent work has studied the transverse densities at peripheral distances b = O(M{pi}{sup -1}), where they are governed by universal chiral dynamics and can be computed in a model-independent manner. Of particular interest is the comparison of the peripheral charge and magnetization densities. We summarize (a) their interpretation as spin-independent and -dependent current matrix elements; (b) the leading-order chiral effective field theory results; (c) their mechanical interpretation in the light-front formulation; (d) the large-N_c limit of QCD and the role of {Delta} intermediate states; (e) the connection with generalized parton distributions and peripheral high-energy scattering processes.
Longitudinal shear wave and transverse dilatational wave in solids.
Catheline, S; Benech, N
2015-02-01
Dilatation wave involves compression and extension and is known as the curl-free solution of the elastodynamic equation. Shear wave on the contrary does not involve any change in volume and is the divergence-free solution. This letter seeks to examine the elastodynamic Green's function through this definition. By separating the Green's function in divergence-free and curl-free terms, it appears first that, strictly speaking, the longitudinal wave is not a pure dilatation wave and the transverse wave is neither a pure shear wave. Second, not only a longitudinal shear wave but also a transverse dilatational wave exists. These waves are shown to be a part of the solution known as coupling terms. Their special motion is carefully described and illustrated.
Transverse electron-scale instability in relativistic shear flows.
Alves, E P; Grismayer, T; Fonseca, R A; Silva, L O
2015-08-01
Electron-scale surface waves are shown to be unstable in the transverse plane of a sheared flow in an initially unmagnetized collisionless plasma, not captured by (magneto)hydrodynamics. It is found that these unstable modes have a higher growth rate than the closely related electron-scale Kelvin-Helmholtz instability in relativistic shears. Multidimensional particle-in-cell simulations verify the analytic results and further reveal the emergence of mushroomlike electron density structures in the nonlinear phase of the instability, similar to those observed in the Rayleigh Taylor instability despite the great disparity in scales and different underlying physics. This transverse electron-scale instability may play an important role in relativistic and supersonic sheared flow scenarios, which are stable at the (magneto)hydrodynamic level. Macroscopic (≫c/ωpe) fields are shown to be generated by this microscopic shear instability, which are relevant for particle acceleration, radiation emission, and to seed magnetohydrodynamic processes at long time scales.
Transverse beam coupling impedance of the CERN Proton Synchrotron
NASA Astrophysics Data System (ADS)
Persichelli, S.; Migliorati, M.; Biancacci, N.; Gilardoni, S.; Metral, E.; Salvant, B.
2016-04-01
Beam coupling impedance is a fundamental parameter to characterize the electromagnetic interaction of a particle beam with the surrounding environment. Synchrotron machine performances are critically affected by instabilities and collective effects triggered by beam coupling impedance. In particular, transverse beam coupling impedance is expected to impact beam dynamics of the CERN Proton Synchrotron (PS), since a significant increase in beam intensity is foreseen within the framework of the LHC Injectors Upgrade (LIU) project. In this paper we describe the study of the transverse beam coupling impedance of the PS, taking into account the main sources of geometrical impedance and the contribution of indirect space charge at different energies. The total machine impedance budget, determined from beam-based dedicated machine measurement sessions, is also discussed and compared with the theoretical model.
Transverse Charge and Magnetization Densities in the Nucleon's Chiral Periphery
NASA Astrophysics Data System (ADS)
Granados, C.; Weiss, C.
2014-01-01
In the light-front description of nucleon structure the electromagnetic form factors are expressed in terms of frame-independent transverse densities of charge and magnetization. Recent work has studied the transverse densities at peripheral distances $b = O(M_{\\pi}^{-1}), where they are governed by universal chiral dynamics and can be computed in a model-independent manner. Of particular interest is the comparison of the peripheral charge and magnetization densities. We summarize (a) their interpretation as spin-independent and -dependent current matrix elements; (b) the leading-order chiral effective field theory results; (c) their mechanical interpretation in the light-front formulation; (d) the large-Nc limit of QCD and the role of Δ intermediate states; (e) the connection with generalized parton distributions and peripheral high-energy scattering processes.
Decay of transverse correlations in quantum Heisenberg models
Björnberg, Jakob E. E-mail: daniel@ueltschi.org; Ueltschi, Daniel E-mail: daniel@ueltschi.org
2015-04-15
We study a class of quantum spin systems that include the S=1/2 Heisenberg and XY-models and prove that two-point correlations exhibit exponential decay in the presence of a transverse magnetic field. The field is not necessarily constant, it may be random, and it points in the same direction. Our proof is entirely probabilistic and it relies on a random loop representations of the correlation functions, on stochastic domination and on first-passage percolation.
Electric sail control mode for amplified transverse thrust
NASA Astrophysics Data System (ADS)
Toivanen, P.; Janhunen, P.; Envall, J.
2015-01-01
The electric solar wind sail produces thrust by centrifugally spanned high voltage tethers interacting with the solar wind protons. The sail attitude can be controlled and attitude maneuvers are possible by tether voltage modulation synchronous with the sail rotation. Especially, the sail can be inclined with respect to the solar wind direction to obtain transverse thrust to change the osculating orbit angular momentum. Such an inclination has to be maintained by a continual control voltage modulation. Consequently, the tether voltage available for the thrust is less than the maximum voltage provided by the power system. Using a spherical pendulum as a model for a single rotating tether, we derive analytical estimations for the control efficiency for two separate sail control modes. One is a continuous control modulation that corresponds to strictly planar tether tip motion. The other is an on-off modulation with the tether tip moving along a closed loop on a saddle surface. The novel on-off mode is introduced here to both amplify the transverse thrust and reduce the power consumption. During the rotation cycle, the maximum voltage is applied to the tether only over two thrusting arcs when most of the transverse thrust is produced. In addition to the transverse thrust, we obtain the thrusting angle and electric power consumption for the two control modes. It is concluded that while the thrusting angle is about half of the sail inclination for the continuous modulation it approximately equals to the inclination angle for the on-off modulation. The efficiency of the on-off mode is emphasized when power consumption is considered, and the on-off mode can be used to improve the propulsive acceleration through the reduced power system mass.
Extra Dimensions in Photon or Jet plus Missing Transverse Energy
Cardaci, Marco
2010-02-10
Recent studies of the CMS collaboration are presented on the sensitivity to searches for large (ADD) extra dimensions in channels with missing transverse energy (MET), i.e. the channels jets plus MET and photon plus MET. These studies are based on detailed detector simulation, including all Standard Model backgrounds. Particular emphasis is given to possible early discoveries, i.e. with 100 pb{sup -1} or less. Projected 95% CL exclusion limits as function of luminosity are presented as well.
Magnetohydrodynamic channel flows with weak transverse magnetic fields.
Rothmayer, A P
2014-07-28
Magnetohydrodynamic flow of an incompressible fluid through a plane channel with slowly varying walls and a magnetic field applied transverse to the channel is investigated in the high Reynolds number limit. It is found that the magnetic field can first influence the hydrodynamic flow when the Hartmann number reaches a sufficiently large value. The magnetic field is found to suppress the steady and unsteady viscous flow near the channel walls unless the wall shapes become large.
Transversely polarized source cladding for an optical fiber
NASA Technical Reports Server (NTRS)
Egalon, Claudio Oliveira (Inventor); Rogowski, Robert S. (Inventor)
1994-01-01
An optical fiber comprising a fiber core having a longitudinal symmetry axis is provided. An active cladding surrounds a portion of the fiber core and comprises light-producing sources which emit light in response to chemical or light excitation. The cladding sources are oriented transversely with respect to the longitudinal axis of the fiber core. This polarization results in a superior power efficiency compared to active cladding sources that are randomly polarized or longitudinally polarized parallel with the longitudinal symmetry axis.
Transversity and Collins Fragmentation Functions: Towards a New Global Analysis
Anselmino, M.; Boglione, M.; Melis, S.; Prokudin, A.; D'Alesio, U.; Kotzinian, A.; Murgia, F.
2009-08-04
We present an update of a previous global analysis of the experimental data on azimuthal asymmetries in semi-inclusive deep inelastic scattering (SIDIS), from the HERMES and COMPASS Collaborations, and in e{sup +}e{sup -}{yields}h{sub 1}h{sub 2}X processes, from the Belle Collaboration. Compared to the first extraction, a more precise determination of the Collins fragmentation function and the transversity distribution function for u and d quarks is obtained.
Issues of the transverse feedback systems design at the SSC
Chou, W.; Peterson, J.
1993-05-01
The transverse feedback systems are needed at the SSC for several different reasons. The requirements of these systems are analyzed and specified. In addition to the general requirements (power, bandwidth and gain), specific attention is given to the noises in the systems, which need to be controlled in order to keep the emittance growth at a tolerable rate. A quantitative treatment is given to specify the allowable noise level in the feedback systems.
QCD Evolution of the Transverse Momentum Dependent Correlations
Zhou, Jian; Liang, Zuo-Tang; Yuan, Feng
2008-12-10
We study the QCD evolution for the twist-three quark-gluon correlation functions associated with the transverse momentum odd quark distributions. Different from that for the leading twist quark distributions, these evolution equations involve more general twist-three functions beyond the correlation functions themselves. They provide important information on nucleon structure, and can be studied in the semi-inclusive hadron production in deep inelastic scattering and Drell-Yan lepton pair production in pp scattering process.
Transverse momentum dependent quark densities from Lattice QCD
Bernhard Musch,Philipp Hagler,John Negele,Andreas Schafer
2011-02-01
We study transverse momentum dependent parton distribution functions (TMDs) with non-local operators in lattice QCD, using MILC/LHPC lattices. Results obtained with a simpli?ed operator geometry show visible dipole de- formations of spin-dependent quark momentum densities. We discuss the basic concepts of the method, including renormalization of the gauge link, and an ex- tension to a more elaborate operator geometry that would allow us to analyze process-dependent TMDs such as the Sivers-function.
Transverse momentum distributions inside the nucleon from Lattice QCD
Bernhard Musch, Philipp Hagler, John Negele, Andreas Schafer
2010-06-01
We study transverse momentum dependent parton distribution functions (TMDs) with non-local operators in lattice QCD, using MILC/LHPC lattices. Results obtained with a simplified operator geometry show visible dipole deformations of spin-dependent quark momentum densities. We discuss the basic concepts of the method, including renormalization of the gauge link, and an extension to a more elaborate operator geometry that would allow us to analyze process-dependent TMDs such as the Sivers-function.
Delaminations in composite plates under transverse static loads - Experimental results
NASA Technical Reports Server (NTRS)
Finn, Scott R.; He, Yi-Fei; Springer, George S.
1992-01-01
Tests were performed measuring the damage initiation loads and the locations, shapes, and sizes of delaminations in Fiberite T300/976 graphite/epoxy, Fiberite IM7/977-2 graphite-toughened epoxy, and ICI APC-2 graphite-PEEK plates subjected to transverse static loads. The data were compared to the results of the Finn-Springer model, and good agreements were found between the measured and calculated delamination lengths and widths.
Inductively stabilized, long pulse duration transverse discharge apparatus
Sze, Robert C.
1986-01-01
An inductively stabilized, long pulse duration transverse discharge apparatus. The use of a segmented electrode where each segment is attached to an inductive element permits high energy, high efficiency, long-pulsed laser outputs to be obtained. The present apparatus has been demonstrated with rare-gas halide lasing media. Orders of magnitude increase in pulse repetition frequency are obtained in lasing devices that do not utilize gas flow.
Transverse microcracking in Celion 6000/PMR-15 graphite-polyimide
NASA Technical Reports Server (NTRS)
Mills, J. S.; Herakovich, C. T.; Davis, J. G., Jr.
1979-01-01
The effects of room temperature tensile loading and five thermal loadings, in the range -320 F (-196C) to 625F (330CC), upon the development of transverse microcracks (TVM) in Celion 6000/PMR-15 graphite-polyimide laminates were investigated. Microcracks were observed using a replicating technique, microscopy and X-ray. The mechanical or thermal load at which microcracking initiates and the ply residual stresses were predicted using laminate analysis with stress- and temperature-dependent material properties.
High-energy transversely pumped alkali vapor laser
NASA Astrophysics Data System (ADS)
Zweiback, J.; Komashko, A.
2011-03-01
We report on the results from our transversely pumped alkali laser. This system uses an Alexandrite laser to pump a stainless steel laser head. The system uses methane and helium as buffer gasses. Using rubidium, the system produced up to 40 mJ of output energy when pumped with 63 mJ. Slope efficiency was 75%. Using potassium as the lasing species the system produced 32 mJ and a 53% slope efficiency.
Spatiotemporal toroidal waves from the transverse second-harmonic generation.
Saltiel, Solomon M; Neshev, Dragomir N; Fischer, Robert; Krolikowski, Wieslaw; Arie, Ady; Kivshar, Yuri S
2008-03-01
We study the second-harmonic generation via transversely matched interaction of two counterpropagating ultrashort pulses in chi(2) photonic structures. We show that the emitted second-harmonic wave attains the form of spatially expanding toroid with the initial thickness given by the cross correlation of the pulses. We demonstrate the formation of such toroidal waves in crystals with random ferroelectric domains as well as in annularly poled nonlinear photonic structures.
Transverse confinement of waves in three-dimensional random media.
Cherroret, N; Skipetrov, S E; van Tiggelen, B A
2010-11-01
We study the transmission of a tightly focused beam through a thick slab of three-dimensional disordered medium in the Anderson localized regime. We show that the transverse profile of the transmitted beam exhibits clear signatures of Anderson localization and that its mean square width provides a direct measure of the localization length. For a short incident pulse, the width is independent of absorption.
Delaminations in composite plates under transverse static loads - Experimental results
NASA Astrophysics Data System (ADS)
Finn, Scott R.; He, Yi-Fei; Springer, George S.
1992-11-01
Tests were performed measuring the damage initiation loads and the locations, shapes, and sizes of delaminations in Fiberite T300/976 graphite/epoxy, Fiberite IM7/977-2 graphite-toughened epoxy, and ICI APC-2 graphite-PEEK plates subjected to transverse static loads. The data were compared to the results of the Finn-Springer model, and good agreements were found between the measured and calculated delamination lengths and widths.
Persistent Mullerian Duct Syndrome with Transverse Testicular Ectopia
Kumar, P. Naresh; Venugopala, Kandgal
2015-01-01
Persistent Mullerian duct syndrome (PMDS) is a rare form of male pseudohermaphroditism characterized by the presence of Mullerian duct structures in a normal male with 46, XY karyotype. Transverse testicular ectopia (TTE) is rare form of testicular ectopia in which two testes are located on one inguinal side. The opposite scrotum is empty. PMDS with TTE is rare. We report a case of PMDS with TTE discovered during surgery for a right inguinal hernia in a 25-year-old male. PMID:27512542
Sea quark transverse momentum distributions and dynamical chiral symmetry breaking
Schweitzer, Peter; Strikman, Mark; Weiss, Christian
2014-01-01
Recent theoretical studies have provided new insight into the intrinsic transverse momentum distributions of valence and sea quarks in the nucleon at a low scale. The valence quark transverse momentum distributions (q - qbar) are governed by the nucleon's inverse hadronic size R{sup -1} ~ 0.2 GeV and drop steeply at large p{sub T}. The sea quark distributions (qbar) are in large part generated by non-perturbative chiral-symmetry breaking interactions and extend up to the scale rho{sup -1} ~ 0.6 GeV. These findings have many implications for modeling the initial conditions of perturbative QCD evolution of TMD distributions (starting scale, shape of p{sub T}. distributions, coordinate-space correlation functions). The qualitative difference between valence and sea quark intrinsic p{sub T}. distributions could be observed experimentally, by comparing the transverse momentum distributions of selected hadrons in semi-inclusive deep-inelastic scattering, or those of dileptons produced in pp and pbar-p scattering.
Spontaneous perforation of solitary ulcer of transverse colon.
Galanis, Ioannis; Dragoumis, Dimitrios; Kalogirou, Thomas; Lakis, Sotiris; Kotakidou, Rodi; Atmatzidis, Konstantinos
2010-01-01
Spontaneous ruptures of the colon and rectum are extremely uncommon clinical entities and always require laparotomy. A 44-year-old female was admitted with a 12-hour history of severe abdominal pain periumbilically and at the right hypochondrium. The patient was immediately transferred to the department of surgery for close surgical observation. Computed tomography (CT) of the entire abdomen performed just before the operation demonstrated thickening of the wall of the ascending colon with pericolic fat stranding. Surgery revealed a perforation at the antimesenteric wall of the transverse colon and segmental colectomy of the transverse colon was performed. The histological evaluation demonstrated a perforated solitary ulcer of the transverse colon. There are only few known etiologic factors concerning spontaneous ruptures of the colon and rectum and usually none of these causative factors can easily be recognised. Their clinical appearance is most of the times acute abdomen and, despite the use of all appropriate diagnostic methods, the diagnosis is usually set postoperatively. PMID:20090246
Adaptive robust control of longitudinal and transverse electron beam profiles
NASA Astrophysics Data System (ADS)
Rezaeizadeh, Amin; Schilcher, Thomas; Smith, Roy S.
2016-05-01
Feedback control of the longitudinal and transverse electron beam profiles are considered to be critical for beam control in accelerators. In the feedback scheme, the longitudinal or transverse beam profile is measured and compared to a desired profile to give an error estimate. The error is then used to act on the appropriate actuators to correct the profile. The role of the transverse feedback is to steer the beam in a particular trajectory, known as the "orbit." The common approach for orbit correction is based on approximately inverting the response matrix, and in the best case, involves regulating or filtering the singular values. In the current contribution, a more systematic and structured way of handling orbit correction is introduced giving robustness against uncertainties in the response matrix. Moreover, the input bounds are treated to avoid violating the limits of the corrector currents. The concept of the robust orbit correction has been successfully tested at the SwissFEL injector test facility. In the SwissFEL machine, a photo-injector laser system extracts electrons from a cathode and a similar robust control method is developed for the longitudinal feedback control of the current profile of the electron bunch. The method manipulates the angles of the crystals in the laser system to produce a desired charge distribution over the electron bunch length. This approach paves the way towards automation of laser pulse stacking.
NASA Astrophysics Data System (ADS)
Soong, Shiao-Bin
We report in this thesis the simultaneous measurement of the longitudinal-transverse response functions, fLT and fLT' , and the transverse-transverse response function fTT of the deuteron. The quasi- elastic H2(e->, e'p)n experiment reported here was conducted at the MIT/Bates Linear Accelerator Center in February, 1997. The experiment was carried out with a 40% polarized, 800 MeV electron beam. The measurement took place in the Bates South Hall using the One Hundred Inch Proton Spectrometer (OHIPS) as the electron spectrometer. It was placed at an angle of 37.27° and the energy transfer, ω, was set for quasi-elastic kinematics with the square of the four-momentum transfer, Q 2, equal to -0.22(GeV/c) 2 . Three out-of- plane proton spectrometers (OOPS) were positioned at fcmpq = (0°, 90°, 180°), respectively, for a given qlabpq of 23.5°. This allowed the simultaneous measurement of fLT,fTT and fLT' at a central missing momentum of ~200 (MeV/ c). The measured asymmetries, cross sections and response functions are compared with different theoretical models. (Copies available exclusively from MIT Libraries, Rm. 14- 0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)
Genesis of transverse kame trains in eastern Poland
NASA Astrophysics Data System (ADS)
Terpiłowski, Sławomir
2007-01-01
Transverse kames, forming trains perpendicular to the direction of ice-sheet advance, are rare morphological elements in previously glaciated areas. The genesis of an example from the ice-contact zone of the Wartanian glaciation in eastern Poland is discussed. The transverse kames there form two main, distinctly separated, sub-parallel trains. Their sedimentary successions fill erosional troughs incised in the pre-Wartanian deposits on northern slopes. They consist of thick glaciofluvial sand and glaciofluvial/glaciolacustrine sandy/silty units that are covered with a thin, usually discontinuous, glacial till succession. The genesis of this kame type has been modelled. It is concluded that transverse kames developed in two phases: (1) erosion of the substratum in subglacial channels during initial deglaciation, and (2) glaciofluvial deposition in crevasses during advanced deglaciation (in the form of low-energy fans periodically submerged under stagnant water), followed locally by a cover of flowtills. Both the ablation of the ice and the accumulation of the kame deposits were controlled by the co-occurrence of ice zones either enriched or impoverished with sediment. Zonal enrichment of ice with debris was determined by the development of shear zones over substratum elevations that were inclined up-ice. The formation and subsequent infilling of crevasses both took place in zones of relatively clean ice, so that the resulting kames form a train perpendicular to the direction of ice movement.
Multiplicity dependence of transverse momentum in hadronic collisions
NASA Technical Reports Server (NTRS)
Saint Amand, J.; Uritam, R. A.
1976-01-01
The process of secondary-particle emission in hadron-hadron collisions is analytically studied using a simple model of hadron structure. The model neglects the 'size' of the hadron constituents, considering a hadron as a continuous distribution of matter according to a step function of radius R. A version of the eikonal approximation is applied to derive the relative probability for interaction and emission of secondaries when the impact parameter b is smaller than 2R. On the basis of these assumptions, and using the uncertainty relation, an empirical parameterization is obtained for the dependence of the transverse momentum of charged secondaries on their multiplicity in the case of high-energy proton-proton collisions. Comparison with experimental data at 28 GeV/c yields agreement to within about 3%. The analysis shows that at a fixed beam momentum, the transverse momentum decreases with increasing multiplicity, and that for a given multiplicity, the transverse momentum exhibits a slow increase with beam momentum.
Interface module for transverse energy input to dye laser modules
English, R.E. Jr.; Johnson, S.A.
1994-10-11
An interface module for transverse energy input to dye laser modules is provided particularly for the purpose of delivering enhancing transverse energy beams in the form of illumination bar to the lasing zone of a dye laser device, in particular to a dye laser amplifier. The preferred interface module includes an optical fiber array having a plurality of optical fibers arrayed in a co-planar fashion with their distal ends receiving coherent laser energy from an enhancing laser source, and their proximal ends delivered into a relay structure. The proximal ends of the optical fibers are arrayed so as to be coplanar and to be aimed generally at a common point. The transverse energy beam array delivered from the optical fiber array is acted upon by an optical element array to produce an illumination bar which has a cross section in the form of a elongated rectangle at the position of the lasing window. The illumination bar is selected to have substantially uniform intensity throughout. 5 figs.
Interface module for transverse energy input to dye laser modules
English, Jr., Ronald E.; Johnson, Steve A.
1994-01-01
An interface module (10) for transverse energy input to dye laser modules is provided particularly for the purpose of delivering enhancing transverse energy beams (36) in the form of illumination bar (54) to the lasing zone (18) of a dye laser device, in particular to a dye laser amplifier (12). The preferred interface module (10) includes an optical fiber array (30) having a plurality of optical fibers (38) arrayed in a co-planar fashion with their distal ends (44) receiving coherent laser energy from an enhancing laser source (46), and their proximal ends (4) delivered into a relay structure (3). The proximal ends (42) of the optical fibers (38) are arrayed so as to be coplanar and to be aimed generally at a common point. The transverse energy beam array (36) delivered from the optical fiber array (30) is acted upon by an optical element array (34) to produce an illumination bar (54) which has a cross section in the form of a elongated rectangle at the position of the lasing window (18). The illumination bar (54) is selected to have substantially uniform intensity throughout.
Dysferlin and myoferlin regulate transverse tubule formation and glycerol sensitivity.
Demonbreun, Alexis R; Rossi, Ann E; Alvarez, Manuel G; Swanson, Kaitlin E; Deveaux, H Kieran; Earley, Judy U; Hadhazy, Michele; Vohra, Ravneet; Walter, Glenn A; Pytel, Peter; McNally, Elizabeth M
2014-01-01
Dysferlin is a membrane-associated protein implicated in muscular dystrophy and vesicle movement and function in muscles. The precise role of dysferlin has been debated, partly because of the mild phenotype in dysferlin-null mice (Dysf). We bred Dysf mice to mice lacking myoferlin (MKO) to generate mice lacking both myoferlin and dysferlin (FER). FER animals displayed progressive muscle damage with myofiber necrosis, internalized nuclei, and, at older ages, chronic remodeling and increasing creatine kinase levels. These changes were most prominent in proximal limb and trunk muscles and were more severe than in Dysf mice. Consistently, FER animals had reduced ad libitum activity. Ultrastructural studies uncovered progressive dilation of the sarcoplasmic reticulum and ectopic and misaligned transverse tubules in FER skeletal muscle. FER muscle, and Dysf- and MKO-null muscle, exuded lipid, and serum glycerol levels were elevated in FER and Dysf mice. Glycerol injection into muscle is known to induce myopathy, and glycerol exposure promotes detachment of transverse tubules from the sarcoplasmic reticulum. Dysf, MKO, and FER muscles were highly susceptible to glycerol exposure in vitro, demonstrating a dysfunctional sarcotubule system, and in vivo glycerol exposure induced severe muscular dystrophy, especially in FER muscle. Together, these findings demonstrate the importance of dysferlin and myoferlin for transverse tubule function and in the genesis of muscular dystrophy.
Dysferlin and Myoferlin Regulate Transverse Tubule Formation and Glycerol Sensitivity
Demonbreun, Alexis R.; Rossi, Ann E.; Alvarez, Manuel G.; Swanson, Kaitlin E.; Deveaux, H. Kieran; Earley, Judy U.; Hadhazy, Michele; Vohra, Ravneet; Walter, Glenn A.; Pytel, Peter; McNally, Elizabeth M.
2015-01-01
Dysferlin is a membrane-associated protein implicated in muscular dystrophy and vesicle movement and function in muscles. The precise role of dysferlin has been debated, partly because of the mild phenotype in dysferlin-null mice (Dysf). We bred Dysf mice to mice lacking myoferlin (MKO) to generate mice lacking both myoferlin and dysferlin (FER). FER animals displayed progressive muscle damage with myofiber necrosis, internalized nuclei, and, at older ages, chronic remodeling and increasing creatine kinase levels. These changes were most prominent in proximal limb and trunk muscles and were more severe than in Dysf mice. Consistently, FER animals had reduced ad libitum activity. Ultrastructural studies uncovered progressive dilation of the sarcoplasmic reticulum and ectopic and misaligned transverse tubules in FER skeletal muscle. FER muscle, and Dysf- and MKO-null muscle, exuded lipid, and serum glycerol levels were elevated in FER and Dysf mice. Glycerol injection into muscle is known to induce myopathy, and glycerol exposure promotes detachment of transverse tubules from the sarcoplasmic reticulum. Dysf, MKO, and FER muscles were highly susceptible to glycerol exposure in vitro, demonstrating a dysfunctional sarcotubule system, and in vivo glycerol exposure induced severe muscular dystrophy, especially in FER muscle. Together, these findings demonstrate the importance of dysferlin and myoferlin for transverse tubule function and in the genesis of muscular dystrophy. PMID:24177035
Studies of transverse momentum dependent parton distributions and Bessel weighting
Aghasyan, M.; Avakian, H.; De Sanctis, E.; Gamberg, L.; Mirazita, M.; Musch, B.; Prokudin, A.; Rossi, P.
2015-03-01
In this paper we present a new technique for analysis of transverse momentum dependent parton distribution functions, based on the Bessel weighting formalism. The procedure is applied to studies of the double longitudinal spin asymmetry in semi-inclusive deep inelastic scattering using a new dedicated Monte Carlo generator which includes quark intrinsic transverse momentum within the generalized parton model. Using a fully differential cross section for the process, the effect of four momentum conservation is analyzed using various input models for transverse momentum distributions and fragmentation functions. We observe a few percent systematic offset of the Bessel-weighted asymmetry obtained from Monte Carlo extraction compared to input model calculations, which is due to the limitations imposed by the energy and momentum conservation at the given energy/Q2. We find that the Bessel weighting technique provides a powerful and reliable tool to study the Fourier transform of TMDs with controlled systematics due to experimental acceptances and resolutions with different TMD model inputs.
Pion transverse charge density from timelike form factor data
Gerald Miller, Mark Strikman, Christian Weiss
2011-01-01
The transverse charge density in the pion can be represented as a dispersion integral of the imaginary part of the pion form factor in the timelike region. This formulation incorporates information from e+e- annihilation experiments and allows one to reconstruct the transverse density much more accurately than from the spacelike pion form factor data alone. We calculate the transverse density using an empirical parametrization of the timelike pion form factor and estimate that it is determined to an accuracy of ~10% at a distance b ~ 0.1 fm, and significantly better at larger distances. The density is found to be close to that obtained from a zero-width rho meson pole over a wide range and shows a pronounced rise at small distances. The resulting two-dimensional image of the fast-moving pion can be interpreted in terms of its partonic structure in QCD. We argue that the singular behavior of the charge density at the center requires a substantial presence of pointlike configurations in the pion's partonic wave function, which can be probed in other high-momentum transfer processes.
ANTI-PHASE SIGNATURE OF FLARE GENERATED TRANSVERSE LOOP OSCILLATIONS
White, R. S.; Verwichte, E.; Foullon, C.
2013-09-10
Transverse loop oscillations observed by the Atmospheric Imaging Assembly instrument on the Solar Dynamics Observatory spacecraft are studied after an impulsive solar flare eruption on 2012 May 8. We have found that a transversely oscillating coronal loop seen in the 171 A bandpass oscillates in anti-phase with respect to adjacent larger loops seen in the 193 A and 211 A bandpasses. These unusual oscillations are analyzed to investigate the excitation mechanism responsible for their initial inwardly directed anti-phase behavior. The transverse oscillations are analyzed by constructing space-time diagrams from cuts made parallel to the projected loop displacements. The displacement time oscillation profiles are background subtracted and fitted with a damped cosine curve that includes a linear change in the period with time. The local magnetic topology of the active region is modeled using potential field source surface extrapolation. It reveals that the loops are anchored in different topological regions with foot point locations identified on either side of the EUV flare peak emission source. In this context, the oscillation characteristics indicate that the excitation mechanism is closely linked to the local magnetic field topology and the reconnection generated wave dynamics in the active region rather than following an external flare blast wave. We discuss how observations such as these may serve to identify reconnection processes in similar quadrupolar active regions.
Studies of transverse momentum dependent parton distributions and Bessel weighting
Aghasyan, M.; Avakian, H.; De Sanctis, E.; Gamberg, L.; Mirazita, M.; Musch, B.; Prokudin, A.; Rossi, P.
2015-03-01
In this paper we present a new technique for analysis of transverse momentum dependent parton distribution functions, based on the Bessel weighting formalism. The procedure is applied to studies of the double longitudinal spin asymmetry in semi-inclusive deep inelastic scattering using a new dedicated Monte Carlo generator which includes quark intrinsic transverse momentum within the generalized parton model. Using a fully differential cross section for the process, the effect of four momentum conservation is analyzed using various input models for transverse momentum distributions and fragmentation functions. We observe a few percent systematic offset of the Bessel-weighted asymmetry obtained from Montemore » Carlo extraction compared to input model calculations, which is due to the limitations imposed by the energy and momentum conservation at the given energy/Q2. We find that the Bessel weighting technique provides a powerful and reliable tool to study the Fourier transform of TMDs with controlled systematics due to experimental acceptances and resolutions with different TMD model inputs.« less
Difference cross sections of unpolarized SIDIS with transverse momentum dependence
NASA Astrophysics Data System (ADS)
Christova, Ekaterina
2014-09-01
Previously we showed that, based only on charge conjugation and isospin invariance of strong interactions, the difference cross sections of hadrons with opposite charge in semi-inclusive deep inelastic scattering (SIDIS) e+N→l+h+X are expressed solely in terms of the valence-quark densities and certain nonsinglet combinations of fragmentation functions (FFs). This allowed us to determine these quantities in a model-independent way. Now we extend this approach to processes when the transverse momentum of the final hadron is measured as well. We show that the difference cross sections of unpolarized SIDIS on proton and deuterium targets, dσNh+-h-, dσNπ+-π- and dσNK+-K-, are expressed solely in terms of the transverse momentum-dependent (TMD) unpolarized valence-quark densities and FFs, and the valence-quark Boer-Mulders and Collins functions. This allows us to determine them separately and study the flavor dependence of the quark transverse momentum. Measurements on the deuterium target, dσdh+-h-, dσdπ+-π- and dσdK+-K-, provide three independent measurements for the sum of the TMD valence-quark densities and Boer-Mulders functions: (u1,V+d1,V) and (h1,uV⊥+h1,dV⊥).
Studies of transverse momentum dependent parton distributions and Bessel weighting
NASA Astrophysics Data System (ADS)
Aghasyan, M.; Avakian, H.; De Sanctis, E.; Gamberg, L.; Mirazita, M.; Musch, B.; Prokudin, A.; Rossi, P.
2015-03-01
In this paper we present a new technique for analysis of transverse momentum dependent parton distribution functions, based on the Bessel weighting formalism. The procedure is applied to studies of the double longitudinal spin asymmetry in semi-inclusive deep inelastic scattering using a new dedicated Monte Carlo generator which includes quark intrinsic transverse momentum within the generalized parton model. Using a fully differential cross section for the process, the effect of four momentum conservation is analyzed using various input models for transverse momentum distributions and fragmentation functions. We observe a few percent systematic offset of the Bessel-weighted asymmetry obtained from Monte Carlo extraction compared to input model calculations, which is due to the limitations imposed by the energy and momentum conservation at the given energy/ Q 2. We find that the Bessel weighting technique provides a powerful and reliable tool to study the Fourier transform of TMDs with controlled systematics due to experimental acceptances and resolutions with different TMD model inputs.
Probing transverse momentum dependent parton distributions in charmonium and bottomonium production
NASA Astrophysics Data System (ADS)
Mukherjee, Asmita; Rajesh, Sangem
2016-03-01
We propose the study of unpolarized transverse momentum dependent gluon parton distributions as well as the effect of linearly polarized gluons on transverse momentum and rapidity distributions of J /ψ and ϒ production within the framework of transverse momentum dependent factorization employing a color evaporation model (CEM) in an unpolarized proton-proton collision. We estimate the transverse momentum and rapidity distributions of J /ψ and ϒ at LHCb, RHIC and AFTER energies using TMD evolution formalism.
Stripline Transversal Filter Techniques for Sub-picosecond Bunch Timing Measurements
Fox, John D.; Mastorides, Themis; Rivetta, Claudio Hector; Winkle, Daniel Van
2007-07-06
Measurement of time of arrival of a particle bunch is a fundamental beam diagnostic. The PEP-II/ALS/BESSY/PLS longitudinal feedback systems use a planar stripline circuit to convert a 30 ps beam BPM impulse signal into a 4 cycle tone burst at the 6th harmonic of the accelerator RF frequency (2.856 GHz). A phase-detection technique is used to measure the arrival time of these BPM impulses with 200 fs rms single-shot resolution (out of a 330 ps dynamic range). Scaled in frequency, this approach is directly applicable to FEL and other sub-ps regime pulse and timing measurements. The transversal circuit structure is applicable to measurement of microbunches or closely spaced bunches (the PEP-II/ALS/BESSY/PLS examples make independent measurements at 2 ns bunch spacing) and opens up some new diagnostic and control possibilities. This paper reviews the principles of the technique, and uses data from PEP-II operations to predict the limits of performance of this measurement scheme for arrival phase measurement. These predictions are compared with results in the literature from electro-optic sub-picosecond beam timing and phasing diagnostics.
Mok, Jinsik
2014-01-01
Summary This study is motivated in part to better understand multiplexing in wireless communications, which employs photons carrying varying angular momenta. In particular, we examine both transverse electric (TE) and transverse magnetic (TM) waves in either co-rotations or counter-rotations. To this goal, we analyze both Poynting-vector flows and orbital and spin parts of the energy flow density for the combined fields. Consequently, we find not only enhancements but also cancellations between the two modes. To our surprise, the photon spins in the azimuthal direction exhibit a complete annihilation for the counter-rotational case even if the intensities of the colliding waves are of different magnitudes. In contrast, the orbital flow density disappears only if the two intensities satisfy a certain ratio. In addition, the concepts of spin sifters and enantiomer sorting are illustrated. PMID:25383300
NASA Astrophysics Data System (ADS)
Lu, Jie
2016-06-01
In this work, we report analytical results on transverse domain wall (TDW) statics and field-driven dynamics in quasi-one-dimensional biaxial nanowires under arbitrary uniform transverse magnetic fields (TMFs) based on the Landau-Lifshitz-Gilbert equation. Without axial driving fields, the static TDW should be symmetric about its center while twisted in its azimuthal angle distribution. By decoupling polar and azimuthal degrees of freedom, an approximate solution is provided which reproduces these features to a great extent. When an axial driving field is applied, the dynamical behavior of a TDW is viewed as the response of its static profile to external excitations. By means of the asymptotic expansion method, the TDW velocity in the traveling-wave mode is obtained, which provides the extent and boundary of the "velocity-enhancement" effect of TMFs on TDWs in biaxial nanowires. Finally, numerical simulations are performed and strongly support our analytics.
Lee, Hyoung-In; Mok, Jinsik
2014-01-01
This study is motivated in part to better understand multiplexing in wireless communications, which employs photons carrying varying angular momenta. In particular, we examine both transverse electric (TE) and transverse magnetic (TM) waves in either co-rotations or counter-rotations. To this goal, we analyze both Poynting-vector flows and orbital and spin parts of the energy flow density for the combined fields. Consequently, we find not only enhancements but also cancellations between the two modes. To our surprise, the photon spins in the azimuthal direction exhibit a complete annihilation for the counter-rotational case even if the intensities of the colliding waves are of different magnitudes. In contrast, the orbital flow density disappears only if the two intensities satisfy a certain ratio. In addition, the concepts of spin sifters and enantiomer sorting are illustrated.
Bliokh, K. Yu.; Bliokh, Yu. P.
2007-06-15
We present a solution to the problem of partial reflection and refraction of a polarized paraxial Gaussian beam at the interface between two transparent media. The Fedorov-Imbert transverse shifts of the centers of gravity of the reflected and refracted beams are calculated. Our results differ in the general case from those derived previously by other authors. In particular, they obey general conservation law for the beams' total angular momentum but do not obey one-particle conservation laws for individual photons, which have been proposed by [Onoda et al. Phys. Rev. Lett. 93, 083901 (2004)]. We ascertain that these circumstances relate to the artificial model accepted in the literature for the polarized beam; this model does not fit to real beams. The present paper resolves the recent controversy and confirms the results of our previous paper [Bliokh et al. Phys. Rev. Lett. 96, 073903 (2006)]. In addition, a diffraction effect of angular transverse shifts of the reflected and refracted beams is described.
A 0.5 Tesla Transverse-Field Alternating Magnetic Field Demagnetizer
NASA Astrophysics Data System (ADS)
Schillinger, W. E.; Morris, E. R.; Finn, D. R.; Coe, R. S.
2015-12-01
We have built an alternating field demagnetizer that can routinely achieve a maximum field of 0.5 Tesla. It uses an amorphous magnetic core with an air-cooled coil. We have started with a 0.5 T design, which satisfies most of our immediate needs, but we can certainly achieve higher fields. In our design, the magnetic field is transverse to the bore and uniform to 1% over a standard (25 mm) paleomagnetic sample. It is powered by a 1 kW power amplifier and is compatible with our existing sample handler for automated demagnetization and measurement (Morris et al., 2009). It's much higher peak field has enabled us to completely demagnetize many of the samples that previously we could not with commercial equipment. This capability is especially needed for high-coercivity sedimentary and igneous rocks that contain magnetic minerals that alter during thermal demagnetization. It will also enable detailed automated demagnetization of high coercivity phases in extraterrestrial samples, such as native iron, iron-alloy and sulfide minerals that are common in lunar rocks and meteorites. Furthermore, it has opened the door for us to use the rock-magnetic technique of component analysis, using coercivity distributions derived from very detailed AF demagnetization of NRM and remanence produced in the laboratory to characterize the magnetic mineralogy of sedimentary rocks. In addition to the many benefits this instrument has brought to our own research, a much broader potential impact is to replace the transverse coils in automated AF demagnetization systems, which typically are limited to peak fields around 0.1 T.
Bryan, Zachary Bryan, Isaac; Sitar, Zlatko; Collazo, Ramón; Mita, Seiji; Tweedie, James
2015-06-08
Since the band ordering in AlGaN has a profound effect on the performance of UVC light emitting diodes (LEDs) and even determines the feasibility of surface emitting lasers, the polarization properties of emitted light from c-oriented AlGaN and AlGaN-based laser structures were studied over the whole composition range, as well as various strain states, quantum confinements, and carrier densities. A quantitative relationship between the theoretical valence band separation, determined using k•p theory, and the experimentally measured degree of polarization is presented. Next to composition, strain was found to have the largest influence on the degree of polarization while all other factors were practically insignificant. The lowest crossover point from the transverse electric to transverse magnetic polarized emission of 245 nm was found for structures pseudomorphically grown on AlN substrates. This finding has significant implications toward the efficiency and feasibility of surface emitting devices below this wavelength.
Transverse piezoelectric coefficient measurement of flexible lead zirconate titanate thin films
Dufay, T.; Guiffard, B.; Seveno, R.; Thomas, J.-C.
2015-05-28
Highly flexible lead zirconate titanate, Pb(Zr,Ti)O{sub 3} (PZT), thin films have been realized by modified sol-gel process. The transverse piezoelectric coefficient d{sub 31} was determined from the tip displacement of bending-mode actuators made of PZT cantilever deposited onto bare or RuO{sub 2} coated aluminium substrate (16 μm thick). The influence of the thickness of ruthenium dioxide RuO{sub 2} and PZT layers was investigated for Pb(Zr{sub 0.57}Ti{sub 0.43})O{sub 3}. The modification of Zr/Ti ratio from 40/60 to 60/40 was done for 3 μm thick PZT thin films onto aluminium (Al) and Al/RuO{sub 2} substrates. A laser vibrometer was used to measure the beam displacement under controlled electric field. The experimental results were fitted in order to find the piezoelectric coefficient. Very large tip deflections of about 1 mm under low voltage (∼8 V) were measured for every cantilevers at the resonance frequency (∼180 Hz). For a given Zr/Ti ratio of 58/42, it was found that the addition of a 40 nm thick RuO{sub 2} interfacial layer between the aluminium substrate and the PZT layer induces a remarkable increase of the d{sub 31} coefficient by a factor of 2.7, thus corresponding to a maximal d{sub 31} value of 33 pC/N. These results make the recently developed PZT/Al thin films very attractive for both low frequency bending mode actuating applications and vibrating energy harvesting.
Growth and microstructure evolution of the Nb{sub 2}Al-Al{sub 3}Nb eutectic in situ composite
Rios, C.T.; Ferrandini, P.L.; Milenkovic, S.; Caram, R. . E-mail: rcaram@fem.unicamp.br
2005-03-15
In situ composite materials obtained by directional growth of eutectic alloys usually show improved properties, that make them potential candidates for high temperature applications. The eutectic alloy found in the Al-Nb system is composed of the two intermetallic phases Al{sub 3}Nb (D0{sub 22}) and Nb{sub 2}Al (D8{sub b}). This paper describes the directional solidification of an Al-Nb eutectic alloy using a Bridgman type facility at growth rates varying from 1.0 to 2.9 cm/h. Longitudinal and transverse sections of grown samples were characterized regarding the solidification microstructure by using optical and scanning electron microscopy, energy dispersive spectroscopy (EDS) and X-ray diffraction. Despite both phases being intermetallic compounds, the eutectic microstructure obtained was very regular. The results obtained were discussed regarding the effect of the growth rate on the microstructure, lamellar-rod transition and variation of phase volume fraction.
Mechanical properties and microstructure of Al-Li-Cu-Mg-Zr die forgings
NASA Astrophysics Data System (ADS)
Webster, Donald; Kirkbride, Richard
1986-11-01
Four forgings of Al 8090 alloy were evaluated for strength, toughness, and stress corrosion resistance. A microstructural evaluation was also conducted. The forgings easily met the strength requirements for Al 7075-T73 but only just met the 7 pct minimum elongation requirement. The stress corrosion threshold was less than 35 MPa in the short transverse orientation, a value that is far below the 310 MPa minimum often required for Al 7075-T73. Fracture in areas which received low forging reductions was intergranular, while fracture in more heavily forged areas was also along subgrain boundaries. Possible mechanisms for the low toughness and stress corrosion resistance of Al-Li alloys are discussed.
Dissipative Landau-Zener quantum dynamics with transversal and longitudinal noise
NASA Astrophysics Data System (ADS)
Javanbakht, S.; Nalbach, P.; Thorwart, M.
2015-05-01
We determine the Landau-Zener transition probability in a dissipative environment including both longitudinal as well as transversal quantum-mechanical noise originating from a single noise source. For this, we use the numerically exact quasiadiabatic path integral, as well as the approximative nonequilibrium Bloch equations. We find that transversal quantum noise in general influences the Landau-Zener probability much more strongly than longitudinal quantum noise does at a given temperature and system-bath coupling strength. In other words, transversal noise contributions become important even when the coupling strength of transversal noise is smaller than that of longitudinal noise. We furthermore reveal that transversal noise renormalizes the tunnel coupling independent of temperature. Finally, we show that the effect of mixed longitudinal and transversal noise originating from a single bath cannot be obtained from an incoherent sum of purely longitudinal and purely transversal noise.
Characteristics of thermally-induced transverse cracks in graphite epoxy composite laminates
NASA Technical Reports Server (NTRS)
Adams, D. S.; Bowles, D. E.; Herakovich, C. T.
1983-01-01
The characteristics of thermally induced transverse cracks in T300/5208 graphite-epoxy cross-ply and quasi-isotropic laminates were investigated both experimentally and analytically. The formation of transverse cracks and the subsequent crack spacing present during cool down to -250 F (116K) and thermal cycling between 250 and -250 F (116 and 394K) was investigated. The state of stress in the vicinity of a transverse crack and the influence of transverse cracking on the laminate coefficient of thermal expansion (CTE) was predicted using a generalized plane strain finite element analysis and a modified shear lag analysis. A majority of the cross-ply laminates experienced transverse cracking during the initial cool down to -250 F whereas the quasi-isotropic laminates remained uncracked. The in situ transverse strength of the 90 degree layers was more than 1.9 times greater than the transverse strength of the unidirectional 90 degree material for all laminates investigated.
Guide to transverse projections and mass-constraining variables
Barr, A. J.; Khoo, T. J.; Lester, C. G.; Konar, P.; Kong, K.; Matchev, K. T.; Park, M.
2011-11-01
This paper seeks to demonstrate that many of the existing mass-measurement variables proposed for hadron colliders (m{sub T}, m{sub eff}, m{sub T2}, missing p-vector{sub T}, h{sub T}, {radical}(s-circumflex){sub min}, etc.) are far more closely related to each other than is widely appreciated, and indeed can all be viewed as a common mass-bound specialized for a variety of purposes. A consequence of this is that one may understand better the strengths and weaknesses of each variable, and the circumstances in which each can be used to best effect. In order to achieve this, we find it necessary first to revisit the seemingly empty and infertile wilderness populated by the subscript 'T' (as in 'pe{sub T}') in order to remind ourselves what this process of transversification actually means. We note that, far from being simple, transversification can mean quite different things to different people. Those readers who manage to battle through the barrage of transverse notation distinguishing 'T' from 'v' or or from 'o', and 'early projection' from 'late projection', will find their efforts rewarded towards the end of the paper with (i) a better understanding of how collider mass variables fit together, (ii) an appreciation of how these variables could be generalized to search for things more complicated than supersymmetry, (iii) will depart with an aversion to thoughtless or naieve use of the so-called 'transverse methods' of any of the popular computer Lorentz-vector libraries, and (iv) will take care in their subsequent papers to be explicit about which of the 61 identified variants of the 'transverse mass' they are employing.
Measurement of combustion response to transverse modes at high pressure
NASA Astrophysics Data System (ADS)
Wierman, Matthew Kenneth
A two dimensional transverse combustor capable of producing and modulating an unstable flowfield was tested at Purdue. The combustor used an array of coaxial ox-centered shear injector elements. The oxidizer posts were able to be discretely changed in length between tests to investigate different post resonance conditions. A single Study element was placed in the middle of the driven unsteady flowfield so its response could be measured using pressure measurement and high speed imagery. This approach was supported by past testing of the longitudinal Continuously Variable Resonance Combustor and past transverse chambers. Mean flow rates and pressures were fixed across the series of tests. Phase lag data between pressure measurement locations support a simple linear post-to-chamber interaction mechanism. Phase lags between chamber measurements were unaffected by the change in oxidizer post length. Scaling was established between amplitude levels and post lengths between the longitudinal and transverse combustors, which further supported the proposed post-to-chamber response mechanism. High speed imaging of OH* chemiluminesence was used as a marker of heat release. Mean flame behavior showed broad distribution and flame shortening at high forcing amplitude and compact, elongated flame shape at low forcing amplitude. Multiple image analysis techniques were utilized to process these data. Proper orthogonal decomposition and dynamic mode decomposition showed spatial and temporal character of image time slices sorted by descriptive content and frequency, respectively. These analyses both identified significant behavior at the same frequencies as chamber pressure perturbations. A systematic code was developed to select relevant time slices to generate flame describing functions of image magnitude and phase lag as a function of pressure amplitude. The magnitude flame describing functions showed low amplitude linear behavior with a divergence at high amplitude. For phase lag
The origin of transverse instability of aeolian megaripples
NASA Astrophysics Data System (ADS)
Yizhaq, Hezi; Katra, Itzhak; Schmerler, Erez; Silvestro, Simone
2016-04-01
Two different kinds of sand ripples, normal ripples and megaripples which differ in their sizes, grain-size compositions and morphology are observed in nature. While normal ripples form almost straight lines, megaripples have greater sinuosity due to their transverse instability, a property that causes small undulations to grow in time. The physical origin of this pronounced transverse instability has remained elusive. We studied ripple development in a series of wind tunnel experiments with different mixtures of sand. For unimodal fine sand, initial differences in height diminished in time leading to straight ripples. In contrast, for bimodal sand initial perturbations in height remained and even grew in time resulting in more wavy patterns. The results indicate that the differences in sinuosity between normal and megaripples are due to grain size segregation at three dimensions with a positive feedback between coarse grains and ripples height. The accumulations of coarse particles at the crest allow further growth of the ripples at these locations thus decreasing their migration rate. This in turn allows further accumulation of coarse grains. This mechanism leads to variations of the thickness of the armoring layer along the ripple crest which correlates with crest height. Field measurements of grain size distribution and sinuosity index along megaripple crests support the findings. In addition, the sinuosity of megaripples and TARs (Transverse Aeolian Ridges) on Mars at several locations was calculated from images taken from High Resolution Imaging Science Experiment (HiRISE). These images provide the capability of obtaining orbital images of Mars with a resolution down to 25 cm/pixel. The preliminary results show that due to their bimodal grain-size distribution megaripples are more undulated than TARs. This new look at aeolian bedforms on Mars can help in a better classification of them and improve the understanding of the aeolian processes involved in their
Chiral dynamics and partonic structure at large transverse distances
Strikman, M.; Weiss, C.
2009-12-30
In this paper, we study large-distance contributions to the nucleon’s parton densities in the transverse coordinate (impact parameter) representation based on generalized parton distributions (GPDs). Chiral dynamics generates a distinct component of the partonic structure, located at momentum fractions x≲M_{π}/M_{N} and transverse distances b~1/M_{π}. We calculate this component using phenomenological pion exchange with a physical lower limit in b (the transverse “core” radius estimated from the nucleon’s axial form factor, R_{core}=0.55 fm) and demonstrate its universal character. This formulation preserves the basic picture of the “pion cloud” model of the nucleon’s sea quark distributions, while restricting its application to the region actually governed by chiral dynamics. It is found that (a) the large-distance component accounts for only ~1/3 of the measured antiquark flavor asymmetry d¯-u¯ at x~0.1; (b) the strange sea quarks s and s¯ are significantly more localized than the light antiquark sea; (c) the nucleon’s singlet quark size for x<0.1 is larger than its gluonic size, (b^{2})_{q+q¯}>(b^{2})_{g}, as suggested by the t-slopes of deeply-virtual Compton scattering and exclusive J/ψ production measured at HERA and FNAL. We show that our approach reproduces the general N_{c}-scaling of parton densities in QCD, thanks to the degeneracy of N and Δ intermediate states in the large-N_{c} limit. Finally, we also comment on the role of pionic configurations at large longitudinal distances and the limits of their applicability at small x.
On transverse effects in transport in semi- and superconductors
NASA Astrophysics Data System (ADS)
Tikhonov, Konstantin Sergeevich
In this dissertation, the results obtained during my PhD work are presented. As an introduction, the brief review of the theory of superconducting fluctuations and a short discussion of experimental situation in the field of spin caloritronics are presented. Next, the original study of two important transport transverse effects is reported. The first one is the Hall effect in metallic films, enhanced by super-conducting fluctuations. We develop an appropriate technique, based on solution of Usadel equation in the presence of classical and quantum noise and including leading contributions due to electron-hole asymmetry. This allows us to extend the previously known results for Cooper interaction-dominated transverse conductivity to a broader range of temperatures and magnetic fields, including the vicinity of the magnetic field induced quantum critical point. The second effect under study is Transverse Spin Seebeck Effect (TSSE). The TSSE remains one of the most puzzling of the recently discovered spin-dependent thermoelectric effects merging spin, charge, and thermal physics. We build a theory, which allows to quantitatively interpret the recent experimental results in terms of magnetized electrons, dragged but low-energy out-of-equilibrium phonons. The theory explains the manifestly non-local nature of the TSSE from the fact that phonons that store the energy (thermal) and the phonons that transfer it (subthermal) are located in different parts of the spectrum and have different kinetics. This gives rise to a spectral phonon distribution that deviates from local equilibrium along the substrate and is sensitive to boundary conditions. The theory also predicts a non-magnon origin of the effect in ferromagnetic metals in agreement with observations in recent experiments.
Transverse-structure electrostatic charged particle beam lens
Moran, Michael J.
1998-01-01
Electrostatic particle-beam lenses using a concentric co-planar array of independently biased rings can be advantageous for some applications. Traditional electrostatic lenses often consist of axial series of biased rings, apertures, or tubes. The science of lens design has devoted much attention to finding axial arrangements that compensate for the substantial optical aberrations of the individual elements. Thus, as with multi-element lenses for light, a multi-element charged-particle lens can have optical behavior that is far superior to that of the individual elements. Transverse multiple-concentric-ring lenses achieve high performance, while also having advantages in terms of compactness and optical versatility.
Transverse-structure electrostatic charged particle beam lens
Moran, M.J.
1998-10-13
Electrostatic particle-beam lenses using a concentric co-planar array of independently biased rings can be advantageous for some applications. Traditional electrostatic lenses often consist of axial series of biased rings, apertures, or tubes. The science of lens design has devoted much attention to finding axial arrangements that compensate for the substantial optical aberrations of the individual elements. Thus, as with multi-element lenses for light, a multi-element charged-particle lens can have optical behavior that is far superior to that of the individual elements. Transverse multiple-concentric-ring lenses achieve high performance, while also having advantages in terms of compactness and optical versatility. 7 figs.
Transverse Single Bunch Instability in PEP-X
Wang, L.; Stupakov, G.; /SLAC
2009-06-02
A proposed high-brightness synchrotron light source (PEP-X) is under design at SLAC. The 4.5- GeV PEP-X storage ring has four theoretical minimum emittance (TME) cells to achieve the very low emittance and two double-bend achromat (DBA) cells to provide spaces for IDs. Damping wigglers will be installed in zero-dispersion straights to reduce the emittance below 0.1nm. In this paper, we present a preliminary estimation of the threshold of the transverse mode coupling instability (TMCI). Three approaches have been used in the estimation and they agree well with each other.
SAW convolvers using the transverse-horizontal bilinear field
NASA Astrophysics Data System (ADS)
Monks, T.; Paige, E. G. S.; Woods, R. C.
1983-06-01
The surface-acoustic-wave (SAW) convolver provides a means of achieving high time-bandwidth, programmable signal processing. The operation of most SAW convolver designs has been based on the detection of an electric-polarization field normal to the crystal surface. The field arises from the mixing of two counter-propagating surface-acoustic waves. The present investigation is concerned with a new type of convolver which is based on the detection of the bilinear electric polarization parallel to the crystal surface and to the input wave-front. The new device is called a transverse-horizontal convolver (THC). A new electrode arrangement is needed to detect the polarization.
Are there approximate relations among transverse momentum dependent distribution functions?
Harutyun AVAKIAN; Anatoli Efremov; Klaus Goeke; Andreas Metz; Peter Schweitzer; Tobias Teckentrup
2007-10-11
Certain {\\sl exact} relations among transverse momentum dependent parton distribution functions due to QCD equations of motion turn into {\\sl approximate} ones upon the neglect of pure twist-3 terms. On the basis of available data from HERMES we test the practical usefulness of one such ``Wandzura-Wilczek-type approximation'', namely of that connecting $h_{1L}^{\\perp(1)a}(x)$ to $h_L^a(x)$, and discuss how it can be further tested by future CLAS and COMPASS data.
Transverse flow reactor studies of the dynamics of radical reactions
Macdonald, R.G.
1993-12-01
Radical reactions are in important in combustion chemistry; however, little state-specific information is available for these reactions. A new apparatus has been constructed to measure the dynamics of radical reactions. The unique feature of this apparatus is a transverse flow reactor in which an atom or radical of known concentration will be produced by pulsed laser photolysis of an appropriate precursor molecule. The time dependence of individual quantum states or products and/or reactants will be followed by rapid infrared laser absorption spectroscopy. The reaction H + O{sub 2} {yields} OH + O will be studied.
Transverse mode revival of a light-compensated quantum memory
Yang Fan; Mandel, Torsten; Lutz, Christian; Yuan Zhensheng; Pan Jianwei
2011-06-15
A long-lived quantum memory was developed based on light-compensated cold {sup 87}Rb atoms in a dipole trap. The lifetime of the quantum memory was improved by 40 folds, from 0.67 to 28 ms with the help of a compensation laser beam. Oscillations of the memory efficiency due to the transverse mode breathing of the singly excited spin wave have been clearly observed and clarified with a Monte Carlo simulation procedure. With detailed analysis of the decoherence processes of the spin wave in cold atomic ensembles, this experiment provides a benchmark for the further development of high-quality quantum memories.
Transversity form factors of the pion in chiral quark models
Broniowski, Wojciech; Dorokhov, Alexander E.; Arriola, Enrique Ruiz
2010-11-01
The transversity form factors of the pion, involving matrix elements of bilocal tensor currents, are evaluated in chiral quark models, both in the local Nambu-Jona-Lasinio with the Pauli-Villars regularization, as well as in nonlocal models involving momentum-dependent quark mass. After suitable QCD evolution, the agreement with recent lattice calculations is very good, in accordance to the fact that the spontaneously broken chiral symmetry governs the dynamics of the pion. Meson dominance of form factors with expected meson masses also works properly, conforming to the parton-hadron duality in the considered process.
Hamiltonian Determination with Restricted Access in Transverse Field Ising Chain
NASA Astrophysics Data System (ADS)
Fasihi, Mohammad Ali; Tanaka, Shu; Nakahara, Mikio; Kondo, Yasushi
2011-04-01
We propose a method to evaluate parameters in the Hamiltonian of the Ising chain under site-dependent transverse fields, with a proviso that we can control and measure one of the edge spins only. We evaluate the eigenvalues of the Hamiltonian and the time-evoultion operator exactly for a three-spin chain, from which we obtain the expectation values of σx of the first spin. The parameters are found from the peak positions of the Fourier transform of the expectation value. There are four assumptions in our method, which are mild enough to be satisfied in many physical systems.
Ion trap quantum computing with transverse phonon modes
NASA Astrophysics Data System (ADS)
Zhu, Shi-Liang; Monroe, Chris; Duan, Luming
2006-03-01
We propose a scheme to use the transverse modes to implement conditional phase gates on two trapped ions immersed in a large linear crystal of ions, without the sideband addressing. Comparing with the conventional approach using the longitudinal modes, with the cost that the laser power is slightly stronger, the proposed gate operation can be well inside Lamb-Dicke region and the gate infidelity due to the fluctuation of the effective Rabi frequency as well as the fundamental limits of the cooling procedure are approximately two orders smaller.
Effects of transverse oscillatory waves on turbulent boundary waves
NASA Technical Reports Server (NTRS)
Matulevich, Jonathan; Jacobs, Harold R.
1994-01-01
Studies of the interaction of unsteady (oscillatory) flows with the growth of a turbulent boundary layer on a flat plate have primarily dealt with an oscillatory component in the primary flow direction. Past studies of the 2-D flow have shown little or no increase in the time averaged heat transfer. The present paper deals with a steady axial and an oscillatory transverse flow. It is shown that for such flows the temporal variation for both the turbulent skin friction and heat transfer are such as to yield increased time averaged values.
Scaling, decoupling and transversality of the gluon propagator
Fischer, Christian S.; Smekal, Lorenz von
2011-05-23
In this note we discuss a couple of technical issues relevant to solving the Dyson-Schwinger equation for the gluon propagator in Landau gauge Yang-Mills theory. In the deep infrared functional methods extract a one-parameter family of solutions generically showing a massive behavior referred to as 'decoupling' but also including the so-called 'scaling' solution with a conformal infrared behavior as a limiting case. We emphasize that the latter cannot be ruled out by technical arguments related to the removal of quadratic divergencies and transversality.
Elastic constants of Transversely Isotropically Porous (TIP) materials
Tuchinskii, L.I.; Kalimova, N.L.
1994-11-01
The authors derive formulas describing the dependence of the elastic characteristics of multicapillary materials on the capillary porosity. The investigated materials are classified as transversely isotropic, and the anisotropy in their properties is the result of the directionality of the capillary pores. Analysis of the dependences obtained has shown that the elasticity moduli of these materials may be calculated using formulas suggested for reinforced materials, in which the elastic constants of the fibers are assumed to be equal to zero. The authors derive a relation between the Poisson`s ratios and the capillary porosity.
Dispersive effects of transverse magnet displacements in rolled arc achromats
Fieguth, T.; Kheifets, S.; Murray, J.J.
1986-09-22
The effect of transverse displacements of combined function magnets is investigated where the disperion in not matched due to roll. This dispersion function is perturbed by displacement of combined function magnets either singly or coherently. In the latter case the effect of a systematic (or DC) offset of magnets is examined. This type of error can occur due to systematics in the placement or the readout of Beam Position Monitors or equivalently by correcting the orbit of a beam of the wrong momentum with respect to the Arc magnet excitation. 5 refs., 18 figs.
Transverse ray aberrations of Wolter type 1 telescopes
NASA Technical Reports Server (NTRS)
Saha, Timo T.
1986-01-01
Transverse ray aberration expansions are derived for Wolter type 1 telescopes. The analysis gives third order aberration terms, most of the fifth order terms and two seventh order terms as functions of system parameters and entrance aperture coordinates. The third order distortion is negligible and, therefore, this term is omitted in the expansions. The spot diagrams derived from exact ray tracing and aberration expansions agree well. The importance of fifth and seventh order terms is discussed. The derived aberration expansions are also valid for Wolter type 2 telescopes.
A QCD Analysis of Average Transverse Momentum in Jet Fragmentation
NASA Astrophysics Data System (ADS)
Iguchi, K.; Nakkagawa, H.; Niégawa, A.
1981-08-01
The generalized Altarelli-Parisi equations for the full fragmentation functions of partons are solved within the LLA. The analysis of the average transverse momentum ⪉ngle kT ranglez of hadrons produced inside a jet in e+e- annihilation shows that the LLA calculations of QCD give satisfactory description of the data if we take into account correctly the kinematical restrictions to the evolution of jets. Discussions on the use of the LLA in the phenomenological analyses are also given.
Transverse Resistive Wall Instability in the Two-Beam Accelerator
Whittum, D.H.; Sessler, Andrew M.; Neil, V.K.
1990-06-01
The transverse resistive wall instability in the Two-Beam Accelerator (TBA) is investigated analytically and numerically. Without any damping mechanism, we find one to four e-folds in 100 m, depending on the design. It is found that Landau damping, due to energy spread within a beam slice, is not effective, due to rapid synchrotron oscillations in the FEL ponderomotive well. Damping due to an energy sweep along the beam is also considered and it is found that a small variation in energy along the beam, decreasing from head to tail, can significantly reduce growth. We conclude that the resistive wall instability is not a severe design constraint on a TBA.
Transverse laser cooling of a thermal atomic beam of dysprosium
Leefer, N.; Cingoez, A.; Gerber-Siff, B.; Sharma, Arijit; Torgerson, J. R.; Budker, D.
2010-04-15
A thermal atomic beam of dysprosium atoms is cooled using the 4f{sup 10}6s{sup 2}(J=8){yields}4f{sup 10}6s6p(J=9) transition at 421 nm. The cooling is done via a standing light wave orthogonal to the atomic beam. Efficient transverse cooling to the Doppler limit is demonstrated for all observable isotopes of dysprosium. Branching ratios to metastable states are demonstrated to be <5x10{sup -4}. A scheme for enhancement of the nonzero-nuclear-spin-isotope cooling and a method for direct identification of possible trap states are proposed.
Delaminations in composite plates under transverse impact loads - Experimental results
NASA Technical Reports Server (NTRS)
Finn, Scott R.; He, Ye-Fei; Springer, George S.
1993-01-01
Tests were performed measuring the locations and geometries of delaminations in Fiberite T300/976 graphite/epoxy, Fiberite IM7/977-2 graphite-toughened epoxy, and ICI APC-2 graphite/PEEK plates subjected to transverse impact loads. The data provide specific information on the effects of impactor velocity, impactor mass, material, thickness of back ply group, difference in fiber orientation between adjacent ply groups, plate thickness, and impactor nose radius. The data were compared to the results of the Finn-Springer model. The model was found to describe the data with reasonable accuracy.
Transverse resistive wall impedance for multi-layer round chambers
Alexy Burov and Valeri Lebedev
2002-06-11
The resistive wall impedance is usually calculated assuming the skin depth being much smaller than the chamber thickness. This approximation is not always correct. In particular, it is not valid when the revolution frequency is very low (as in VLHC [1]), or the surface is coated by a thin conductive layer (as for extraction kickers [2]), or for the coherent effects in the closed orbit motion [3]. A method of analytical calculation of the transverse impedance is developed here for multi-layer vacuum chambers and applied to an arbitrary two-layer structure.
A transverse Kelvin-Helmholtz instability in a magnetized plasma
NASA Technical Reports Server (NTRS)
Kintner, P.; Dangelo, N.
1977-01-01
An analysis is conducted of the transverse Kelvin-Helmholtz instability in a magnetized plasma for unstable flute modes. The analysis makes use of a two-fluid model. Details regarding the instability calculation are discussed, taking into account the ion continuity and momentum equations, the solution of a zero-order and a first-order component, and the properties of the solution. It is expected that the linear calculation conducted will apply to situations in which the plasma has experienced no more than a few growth periods.
Numerical studies of transverse curvature effects on transonic flow stability
NASA Technical Reports Server (NTRS)
Macaraeg, M. G.; Daudpota, Q. I.
1992-01-01
A numerical study of transverse curvature effects on compressible flow temporal stability for transonic to low supersonic Mach numbers is presented for axisymmetric modes. The mean flows studied include a similar boundary-layer profile and a nonsimilar axisymmetric boundary-layer solution. The effect of neglecting curvature in the mean flow produces only small quantitative changes in the disturbance growth rate. For transonic Mach numbers (1-1.4) and aerodynamically relevant Reynolds numbers (5000-10,000 based on displacement thickness), the maximum growth rate is found to increase with curvature - the maximum occurring at a nondimensional radius (based on displacement thickness) between 30 and 100.
Transverse and longitudinal beam dynamics studies at the Fermilab photoinjector
Carneiro, J.P.; Barov, N.; Edwards, H.; Fitch, M.; Hartung, W.; Flottmann, K.; Schreiber, S.; Ferrario, M.; /Frascati
2005-01-01
The Fermilab photoinjector produces electron bunches of 1-12 nC charge with an energy of 16-18 MeV. Detailed measurements and optimization of the transverse emittance have been carried out for a number of beam line optics conditions, and at a number of beam line locations. The length of the bunches has also been measured, first for an uncompressed beam (as a function of the charge) and then for a compressed beam of 8 nC charge (as a function of the 9-cell cavity phase). These measurements are presented and compared with the simulation codes HOMDYN and ASTRA.
Transverse instability of line defects of period-2 spiral waves.
Park, Jin-Sung; Woo, Sung-Jae; Lee, Kyoung J
2004-08-27
Spiral waves that arise in period-2 oscillatory media extended in space generically bear "line defects" along which the local kinetics exhibits a period-1 oscillation. Locally, these defect structures can be viewed as a front separating two period-2 oscillatory domains oscillating 2pi out of phase. Here we show that their shape can become sinusoidal with a transverse instability as in bistable fronts. This instability eventually leads to a line-defect filled spatiotemporal chaotic state having erratic proliferations, annihilations, and regenerations of line defects. The same sequence of phenomena is observed in a model reaction-diffusion system as well as in an experimental system.
Observation of shock transverse waves in elastic media.
Catheline, S; Gennisson, J-L; Tanter, M; Fink, M
2003-10-17
We report the first experimental observation of a shock transverse wave propagating in an elastic medium. This observation was possible because the propagation medium, a soft solid, allows one to reach a very high Mach number. In this extreme configuration, the shock formation is observed over a distance of less than a few wavelengths, thanks to a prototype of an ultrafast scanner (that acquires 5000 frames per second). A comparison of these new experimental data with theoretical predictions, based on a modified Burger's equation, shows good agreement.
Segmented waves from a spatiotemporal transverse wave instability.
Yang, Lingfa; Berenstein, Igal; Epstein, Irving R
2005-07-15
We observe traveling waves emitted from Turing spots in the chlorine dioxide-iodine-malonic acid reaction. The newborn waves are continuous, but they break into segments as they propagate, and the propagation of these segments ultimately gives rise to spatiotemporal chaos. We model the wave-breaking process and the motion of the chaotic segments. We find stable segmented spirals as well. We attribute the segmentation to an interaction between front rippling via a transverse instability and front symmetry breaking by a fast-diffusing inhibitor far from the codimension-2 Hopf-Turing bifurcation, and the chaos to a secondary instability of the periodic segmentation.
Delaminations in composite plates under transverse impact loads - Experimental results
NASA Astrophysics Data System (ADS)
Finn, Scott R.; He, Ye-Fei; Springer, George S.
Tests were performed measuring the locations and geometries of delaminations in Fiberite T300/976 graphite/epoxy, Fiberite IM7/977-2 graphite-toughened epoxy, and ICI APC-2 graphite/PEEK plates subjected to transverse impact loads. The data provide specific information on the effects of impactor velocity, impactor mass, material, thickness of back ply group, difference in fiber orientation between adjacent ply groups, plate thickness, and impactor nose radius. The data were compared to the results of the Finn-Springer model. The model was found to describe the data with reasonable accuracy.
Transverse Spin Effects in Future Drell-Yan Experiments
NASA Astrophysics Data System (ADS)
Peng, Jen-Chieh
2015-01-01
We review the current status and future prospect for probing the transverse momentum dependent (TMD) parton distributions using the Drell-Yan process. We focus on the Boer-Mulders and Sivers functions, which are expected to undergo a sign-change from semi-inclusive deep-inelastic scattering (SIDIS) to Drell-Yan process. The constraints of existing Drell-Yan and SIDIS experiments on the signs of these functions are discussed. Future Drell-Yan measurements for the TMDs are also presented.
Impurity effects of transverse Ising model with multi-impurity
NASA Astrophysics Data System (ADS)
Huang, Xuchu; Yang, Zhihua
2015-02-01
We study the transverse Ising spin model with multi-impurity under the exact solution. The influence mechanisms of the concentration, configuration, impurity-inducing-interaction are investigated through the deformation energy, long-range order and the specific heat. It reveals a way that the impurities have crucial effects on the magnetic order of the system, which can be used to scale the order-disorder transition. In particular, the change of the exchange coupling interaction or magnetic field can lead to the deviation of the phase point. Moreover, the impurity excitation cannot be neglected in thermodynamic properties even though the concentration is only a few percent.
Spatial and Temporal Variations in Strain Rates in the Western Transverse Ranges, California
NASA Astrophysics Data System (ADS)
Marshall, S. T.; Funning, G. J.; Owen, S. E.
2012-12-01
We determine the spatial and temporal variations in strain rates in the Transverse Ranges of southern California by combing data from 52 continuous GPS sites in the Plate Boundary Observatory network with InSAR time series. To characterize periodic seasonal motions in the GPS time series, phases and amplitudes of annual and semiannual motions are estimated for each GPS station. We remove these seasonal terms, and then perform Principal Component Analysis on the residual time series to remove common-mode errors. We find that seasonal GPS motions are not strongly dependent on local substrate geology. To quantify the spatial patterns of deformation in greater detail than GPS can provide, we use a persistent scatterer InSAR (PSI) data set comprised of 23 ENVISAT ASAR scenes. The PSI data were derived using the software package, StaMPS [Hooper et al. 2004]. The PSI data show potential anthropogenic subsidence in the Oxnard/Ventura area as well as at a location just south of the Oak Ridge. A highly localized zone of subsidence is also present along the Ventura Avenue anticline, where ongoing petroleum extraction is occurring. Comparison of the InSAR and the GPS projected into the InSAR line of sight, shows general agreement. The relative lack of significant non-tectonic motions in the western Transverse Ranges is in stark contrast to the nearby Los Angeles basin where anthropogenic motions dominate many InSAR scenes. To determine the local tectonic deformation rates, we remove strain associated with the nearby San Andreas fault using a rectangular dislocation model. Direct inversion of the GPS velocities into a triangulated network with variable strain/rotation rates produces a generalized map of variations in tectonic strain rates. The strain rate map shows the largest strain rates to be near the central Ventura basin with rates generally decreasing westward towards the Santa Barbara Channel. To determine compatible regional fault slip rates, we use a forward mechanical
Virtuality and transverse momentum dependence of the pion distribution amplitude
NASA Astrophysics Data System (ADS)
Radyushkin, A. V.
2016-03-01
We describe basics of a new approach to transverse momentum dependence in hard exclusive processes. We develop it in application to the transition process γ*γ →π0 at the handbag level. Our starting point is coordinate representation for matrix elements of operators [in the simplest case, bilocal O (0 ,z ) ] describing a hadron with momentum p . Treated as functions of (p z ) and z2, they are parametrized through virtuality distribution amplitudes (VDA) Φ (x ,σ ) , with x being Fourier conjugate to (p z ) and σ Laplace conjugate to z2. For intervals with z+=0 , we introduce the transverse momentum distribution amplitude (TMDA) Ψ (x ,k⊥), and write it in terms of VDA Φ (x ,σ ). The results of covariant calculations, written in terms of Φ (x ,σ ), are converted into expressions involving Ψ (x ,k⊥). Starting with scalar toy models, we extend the analysis onto the case of spin-1 /2 quarks and QCD. We propose simple models for soft VDAs/TMDAs, and use them for comparison of handbag results with experimental (BABAR and BELLE) data on the pion transition form factor. We also discuss how one can generate high-k⊥ tails from primordial soft distributions.
Structural transect across Ventua basin and western Transverse Ranges
Namson, J.S.
1987-05-01
A retrodeformable cross section that integrates surface and subsurface data across the Ventura basin and western Transverse Ranges illustrates the structural style and evolution of Oligocene to Holocene age structures. Three deformational events are recognized: Oligocene to early Miocene compression, late Miocene through Pliocene normal faulting, and Pleistocene to Holocene compression. Oligocene to early Miocene compression caused uplift and formation of a large antiform north of the Santa Ynez fault in the central part of the range. This antiform is interpreted to be a ramp-related fold associated with movement on a southwest-verging blind thrust fault. Late Miocene through Pliocene age normal faulting along the Oak Ridge fault formed the southern boundary of the Ventura basin. The basin formed by simple block rotation along the normal fault and was filled by up to 6 km of Pliocene and Pleistocene clastic sediment. During Pleistocene to Holocene compression, the Ventura basin and western Transverse Ranges were deformed by both north- and south-verging thrust faults and related folds. The Ventura Avenue anticline is interpreted to be the result of imbricate thrust faulting in the Rincon and Monterey formations. Along the Oak Ridge trend, thrust-related folds rotated and reactivated the late Miocene and Pliocene age normal faults. A restoration of the regional transect documents 34% or 35 km of shortening by thrusting and folding during the Pleistocene to Holocene phase of compression.
Single-Spin Asymmetries and Transversity in QCD
Brodsky, S.J.; /SLAC
2005-12-14
Initial- and final-state interactions from gluon exchange, normally neglected in the parton model, have a profound effect in QCD hard-scattering reactions, leading to leading-twist single-spin asymmetries, diffractive deep inelastic scattering, diffractive hard hadronic reactions, as well as nuclear shadowing and antishadowing-leading-twist physics not incorporated in the light-front wavefunctions of the target computed in isolation. The physics of such processes thus require the understanding of QCD at the amplitude level; in particular, the physics of spin requires an understanding of the phase structure of final-state and initial-state interactions, as well as the structure of the basic wavefunctions of hadrons themselves. I also discuss transversity in exclusive channels, including how one can use single-spin asymmetries to determine the relative phases of the timelike baryon form factors, as well as the anomalous physics of the normal-normal spin-spin correlation observed in large-angle proton-proton elastic scattering. As an illustration of the utility of light-front wavefunctions, the transversity distribution of a single electron is computed, as defined from its two-particle QED quantum fluctuations.
Virtuality and transverse momentum dependence of the pion distribution amplitude
Radyushkin, Anatoly V.
2016-03-08
We describe basics of a new approach to transverse momentum dependence in hard exclusive processes. We develop it in application to the transition process γ*γ → π0 at the handbag level. Our starting point is coordinate representation for matrix elements of operators (in the simplest case, bilocal O (0,z)) describing a hadron with momentum p. Treated as functions of (pz) and z2, they are parametrized through virtuality distribution amplitudes (VDA) Φ(x,σ), with x being Fourier-conjugate to (pz) and σ Laplace-conjugate to z2. For intervals with z+ = 0, we introduce the transverse momentum distribution amplitude (TMDA) ψ(x, k), and writemore » it in terms of VDA Φ(x,σ). The results of covariant calculations, written in terms of Φ(x, σ) are converted into expressions involving ψ(x, k). Starting with scalar toy models, we extend the analysis onto the case of spin-1/2 quarks and QCD. We propose simple models for soft VDAs/TMDAs, and use them for comparison of handbag results with experimental (BaBar and BELLE) data on the pion transition form factor. Furthermore, we discuss how one can generate high-k tails from primordial soft distributions.« less
Transverse electron-scale instability in relativistic shear flows.
Alves, E P; Grismayer, T; Fonseca, R A; Silva, L O
2015-08-01
Electron-scale surface waves are shown to be unstable in the transverse plane of a sheared flow in an initially unmagnetized collisionless plasma, not captured by (magneto)hydrodynamics. It is found that these unstable modes have a higher growth rate than the closely related electron-scale Kelvin-Helmholtz instability in relativistic shears. Multidimensional particle-in-cell simulations verify the analytic results and further reveal the emergence of mushroomlike electron density structures in the nonlinear phase of the instability, similar to those observed in the Rayleigh Taylor instability despite the great disparity in scales and different underlying physics. This transverse electron-scale instability may play an important role in relativistic and supersonic sheared flow scenarios, which are stable at the (magneto)hydrodynamic level. Macroscopic (≫c/ωpe) fields are shown to be generated by this microscopic shear instability, which are relevant for particle acceleration, radiation emission, and to seed magnetohydrodynamic processes at long time scales. PMID:26382337
Numerical modeling of the wind flow over a transverse dune.
Araújo, Ascânio D; Parteli, Eric J R; Pöschel, Thorsten; Andrade, José S; Herrmann, Hans J
2013-01-01
Transverse dunes, which form under unidirectional winds and have fixed profile in the direction perpendicular to the wind, occur on all celestial objects of our solar system where dunes have been detected. Here we perform a numerical study of the average turbulent wind flow over a transverse dune by means of computational fluid dynamics simulations. We find that the length of the zone of recirculating flow at the dune lee - the separation bubble - displays a surprisingly strong dependence on the wind shear velocity, u: it is nearly independent of u for shear velocities within the range between 0.2 m/s and 0.8 m/s but increases linearly with u for larger shear velocities. Our calculations show that transport in the direction opposite to dune migration within the separation bubble can be sustained if u is larger than approximately 0.39 m/s, whereas a larger value of u (about 0.49 m/s) is required to initiate this reverse transport. PMID:24091456
Transverse forces on a vortex in lattice models of superfluids
NASA Astrophysics Data System (ADS)
Sonin, E. B.
2013-12-01
The paper derives the transverse forces (the Magnus and the Lorentz forces) in the lattice models of superfluids in the continuous approximation. The continuous approximation restores translational invariance absent in the original lattice model, but the theory is not Galilean invariant. As a result, calculation of the two transverse forces on the vortex, Magnus force and Lorentz force, requires the analysis of two balances, for the true momentum of particles in the lattice (Magnus force) and for the quasimomentum (Lorentz force) known from the Bloch theory of particles in the periodic potential. While the developed theory yields the same Lorentz force, which was well known before, a new general expression for the Magnus force was obtained. The theory demonstrates how a small Magnus force emerges in the Josephson-junction array if the particle-hole symmetry is broken. The continuous approximation for the Bose-Hubbard model close to the superfluid-insulator transition was developed, which was used for calculation of the Magnus force. The theory shows that there is an area in the phase diagram for the Bose-Hubbard model, where the Magnus force has an inverse sign with respect to that which is expected from the sign of velocity circulation.
Measurements of the Transverse Wakefields Due to Varying Collimator Characteristics
Molloy, S.; Seletskiy, Sergei; Woods, Mike; Smith, Jonathan David Andrew; Beard, Carl David; Fernandez-Hernando, Juan Luis; Watson, Nigel; Bungau, Adriana; Sopczak, Andre; /Lancaster U.
2007-07-06
We report on measurements of the transverse wakefields induced by collimators of differing characteristics. An apparatus allowing the insertion of different collimator jaws into the path of a beam was installed in End Station A (ESA) in SLAC. Eight comparable collimator geometries were designed, including one that would allow easy comparison with previous results, and were installed in this apparatus. Measurements of the beam kick due to the collimator wakefields were made with a beam energy of 28.5 GeV, and beam dimensions of 100 microns vertically and a range of 0.5 to 1.5 mm longitudinally. The trajectory of the beam upstream and downstream of the collimator test apparatus was determined from the outputs of ten BPMs (four upstream and six downstream), thus allowing a measurement of the angular kick imparted to the beam by the collimator under test. The transverse wakefield was inferred from the measured kick. The different aperture designs, data collection and analysis, and initial comparison to theoretical and analytic predictions are presented here.
Transverse electron-scale instability in relativistic shear flows
NASA Astrophysics Data System (ADS)
Alves, E. P.; Grismayer, T.; Fonseca, R. A.; Silva, L. O.
2015-08-01
Electron-scale surface waves are shown to be unstable in the transverse plane of a sheared flow in an initially unmagnetized collisionless plasma, not captured by (magneto)hydrodynamics. It is found that these unstable modes have a higher growth rate than the closely related electron-scale Kelvin-Helmholtz instability in relativistic shears. Multidimensional particle-in-cell simulations verify the analytic results and further reveal the emergence of mushroomlike electron density structures in the nonlinear phase of the instability, similar to those observed in the Rayleigh Taylor instability despite the great disparity in scales and different underlying physics. This transverse electron-scale instability may play an important role in relativistic and supersonic sheared flow scenarios, which are stable at the (magneto)hydrodynamic level. Macroscopic (≫c /ωp e ) fields are shown to be generated by this microscopic shear instability, which are relevant for particle acceleration, radiation emission, and to seed magnetohydrodynamic processes at long time scales.
Fast Transverse Instability and Electron Cloud Measurements in Fermilab Recycler
Eldred, Jeffery; Adamson, Philip; Capista, David; Eddy, Nathan; Kourbanis, Ioanis; Morris, Denton; Thangaraj, Jayakar; Yang, Ming-Jen; Zwaska, Robert; Ji, Yichen
2015-03-01
A new transverse instability is observed that may limit the proton intensity in the Fermilab Recycler. The instability is fast, leading to a beam-abort loss within two hundred turns. The instability primarily affects the first high-intensity batch from the Fermilab Booster in each Recycler cycle. This paper analyzes the dynamical features of the destabilized beam. The instability excites a horizontal betatron oscillation which couples into the vertical motion and also causes transverse emittance growth. This paper describes the feasibility of electron cloud as the mechanism for this instability and presents the first measurements of the electron cloud in the Fermilab Recycler. Direct measurements of the electron cloud are made using a retarding field analyzer (RFA) newly installed in the Fermilab Recycler. Indirect measurements of the electron cloud are made by propagating a microwave carrier signal through the beampipe and analyzing the phase modulation of the signal. The maximum betatron amplitude growth and the maximum electron cloud signal occur during minimums of the bunch length oscillation.
A transverse electron target for heavy ion storage rings
Geyer, Sabrina Meusel, Oliver; Kester, Oliver
2015-01-09
Electron-ion interaction processes are of fundamental interest for several research fields like atomic and astrophysics as well as plasma applications. To address this topic, a transverse electron target based on the crossed beam technique was designed and constructed for the application in storage rings. Using a sheet beam of free electrons in crossed beam geometry promises a good energy resolution and gives access to the interaction region for spectroscopy. The produced electron beam has a length of 10 cm in ion beam direction and a width in the transverse plane of 5 mm. Therewith, electron densities of up to 10{sup 9} electrons/cm{sup 3} are reachable in the interaction region. The target allows the adjustment of the electron beam current and energy in the region of several 10 eV to a few keV. Simulations have been performed regarding the energy resolution for electron-ion collisions and its influence on spectroscopic measurements. Also, the effect on ion-beam optics due to the space charge of the electron beam was investigated. Presently the electron target is integrated into a test bench to evaluate its performance for its dedicated installation at the storage rings of the FAIR facility. Therefore, optical diagnostics of the interaction region and charge state analysis with a magnetic spectrometer is used. Subsequently, the target will be installed temporarily at the Frankfurt Low-Energy Storage Ring (FLSR) for further test measurements.
Single transverse spin asymmetry of prompt photon production
NASA Astrophysics Data System (ADS)
Gamberg, Leonard; Kang, Zhong-Bo
2012-11-01
We study the single transverse spin asymmetry of prompt photon production in high energy proton-proton scattering. We include the contributions from both the direct and fragmentation photons. While the asymmetry for direct photon production receives only the Sivers type of contribution, the asymmetry for fragmentation photons receives both the Sivers and Collins types of contributions. We make a model calculation for quark-to-photon Collins function, which is then used to estimate the Collins asymmetry for fragmentation photons. We find that the Collins asymmetry for fragmentation photons is very small, thus the single transverse spin asymmetry of prompt photon production is mainly coming from the Sivers asymmetry in direct and fragmentation photons. We make predictions for the prompt photon spin asymmetry at RHIC energy, and emphasize the importance of such a measurement. The asymmetry of prompt photon production can provide a good measurement for the important twist-three quark-gluon correlation function, which is urgently needed in order to resolve the "sign mismatch" puzzle.
The in situ transverse lamina strength of composite laminates
NASA Technical Reports Server (NTRS)
Flaggs, D. L.
1983-01-01
The objective of the work reported in this presentation is to determine the in situ transverse strength of a lamina within a composite laminate. From a fracture mechanics standpoint, in situ strength may be viewed as constrained cracking that has been shown to be a function of both lamina thickness and the stiffness of adjacent plies that serve to constrain the cracking process. From an engineering point of view, however, constrained cracking can be perceived as an apparent increase in lamina strength. With the growing need to design more highly loaded composite structures, the concept of in situ strength may prove to be a viable means of increasing the design allowables of current and future composite material systems. A simplified one dimensional analytical model is presented that is used to predict the strain at onset of transverse cracking. While it is accurate only for the most constrained cases, the model is important in that the predicted failure strain is seen to be a function of a lamina's thickness d and of the extensional stiffness bE theta of the adjacent laminae that constrain crack propagation in the 90 deg laminae.
Numerical modeling of the wind flow over a transverse dune
Araújo, Ascânio D.; Parteli, Eric J. R.; Pöschel, Thorsten; Andrade, José S.; Herrmann, Hans J.
2013-01-01
Transverse dunes, which form under unidirectional winds and have fixed profile in the direction perpendicular to the wind, occur on all celestial objects of our solar system where dunes have been detected. Here we perform a numerical study of the average turbulent wind flow over a transverse dune by means of computational fluid dynamics simulations. We find that the length of the zone of recirculating flow at the dune lee — the separation bubble — displays a surprisingly strong dependence on the wind shear velocity, u*: it is nearly independent of u* for shear velocities within the range between 0.2 m/s and 0.8 m/s but increases linearly with u* for larger shear velocities. Our calculations show that transport in the direction opposite to dune migration within the separation bubble can be sustained if u* is larger than approximately 0.39 m/s, whereas a larger value of u* (about 0.49 m/s) is required to initiate this reverse transport. PMID:24091456
Dipole-exchange modes in transversely magnetized ferromagnetic stripes
NASA Astrophysics Data System (ADS)
Arias, Rodrigo; Duan, Zheng; Krivorotov, Ilya
2014-03-01
We present a theory of dipole-exchange modes in transversely magnetized ferromagnetic stripes of rectangular cross sections: a comparison is made with experimental results on Permalloy stripes. The model applies to very thin stripes (of the order of the exchange length): the magnetization is considered uniform over their thickness, and we consider modes of long wavelength along the longitudinal direction of the stripes. An applied magnetic field saturates the stripes along the transverse direction, and we also consider the effect of the exchange and dipolar fields. Under these assumptions we obtain the frequencies and shapes of the modes either considering free or pinned boundary conditions. We obtain good agreement with measurements of the frequency spectra in Permalloy nano wires of several rectangular cross sections: this happens for modes with appreciable amplitude throughout the samples. There is frequency disagreement for edge modes due to limitations of the model, since the effects of roughness, corners and imperfections at the edges of the samples are quite relevant in this case. This work was supported by the NSF Materials World Network Program Grant No. DMR-1210850 and by DOE grant DE-FG02-84ER45083. Also, supported by ``Proyecto ICM FP10-061-F-FIC'', and ``Proyecto FONDECYT 1130192, Conicyt, Chile''.
Measurement of Transverse Emittance in the Fermilab Booster.
NASA Astrophysics Data System (ADS)
Graves, William Sproull
A new beam profile monitor has been built and installed in the Fermilab Booster synchrotron. It nondestructively measures the beam's vertical density distribution on a fast turn-by-turn basis. This enables one to measure the beam's transverse emittance and to observe emittance growth as it occurs. For high intensities (>2 times 10^{12 } protons), the normalized 95% emittance was observed to grow from 6pi mm-mrad at injection to 16pi mm-mrad at extraction. The initial (<5 msec) emittance growth and beam losses are shown to be caused by the space charge tune shift onto integer and 1/2 integer resonance lines. The growth near injection accounts for approximately 40% of the observed emittance increase throughout the acceleration cycle. The remaining 60% is due to two factors: slow linear growth due to betatron-motion driven by noise in the rf system; and faster growth after the transition energy that is caused by coupling of the longitudinal beam motion into the transverse planes.
Transverse beam emittance measurement using quadrupole variation at KIRAMS-430
NASA Astrophysics Data System (ADS)
An, Dong Hyun; Hahn, Garam; Park, Chawon
2015-02-01
In order to produce a 430 MeV/u carbon ion (12 C 6+) beam for medical therapy, the Korea Institute of Radiological & Medical Sciences (KIRAMS) has carried out the development of a superconducting isochronous cyclotron, the KIRAMS-430. At the extraction of the cyclotron, an Energy Selection System (ESS) is located to modulate the fixed beam energy and to drive the ion beam through High Energy Beam Transport (HEBT) into the treatment room. The beam emittance at the ion beamline is to be measured to provide information on designing a beam with high quality. The well-known quadrupole variation method was used to determine the feasibility of measuring the transverse beam emittance. The beam size measured at the beam profile monitor (BPM) is to be utilized and the transformation of beam by transfer matrix is to be applied being taken under various transport condition of varying quadrupole magnetic strength. Two different methods where beam optics are based on the linear matrix formalism and particle tracking with a 3-D magnetic field distribution obtained by using OPERA3D TOSCA, are applied to transport the beam. The fittings for the transformation parameters are used to estimate the transverse emittance and the twiss parameters at the entrance of the quadrupole in the ESS. Including several systematic studies, we conclude that within the uncertainty the estimated emittances are consistent with the ones calculated by using Monte Carlo simulations.
ENERGY CONTENT AND PROPAGATION IN TRANSVERSE SOLAR ATMOSPHERIC WAVES
Goossens, M.; Van Doorsselaere, T.; Soler, R.; Verth, G.
2013-05-10
Recently, a significant amount of transverse wave energy has been estimated propagating along solar atmospheric magnetic fields. However, these estimates have been made with the classic bulk Alfven wave model which assumes a homogeneous plasma. In this paper, the kinetic, magnetic, and total energy densities and the flux of energy are computed for transverse MHD waves in one-dimensional cylindrical flux tube models with a piecewise constant or continuous radial density profile. There are fundamental deviations from the properties for classic bulk Alfven waves. (1) There is no local equipartition between kinetic and magnetic energy. (2) The flux of energy and the velocity of energy transfer have, in addition to a component parallel to the magnetic field, components in the planes normal to the magnetic field. (3) The energy densities and the flux of energy vary spatially, contrary to the case of classic bulk Alfven waves. This last property has the important consequence that the energy flux computed with the well known expression for bulk Alfven waves could overestimate the real flux by a factor in the range 10-50, depending on the flux tube equilibrium properties.
Pion transverse charge density and the edge of hadrons
Carmignotto, Marco; Horn, Tanja; Miller, Gerald A.
2014-08-01
We use the world data on the pion form factor for space-like kinematics and a technique used to extract the proton transverse densities, to extract the transverse pion charge density and its uncertainty due to experimental uncertainties and incomplete knowledge of the pion form factor at large values of Q2. The pion charge density at small values of b<0.1 fm is dominated by this incompleteness error while the range between 0.1-0.3 fm is relatively well constrained. A comparison of pion and proton charge densities shows that the pion is denser than the proton for values of b<0.2 fm. The pion and proton distributions seem to be the same for values of b=0.2-0.6 fm. Future data from Jlab 12 GeV and the EIC will increase the dynamic extent of the data to higher values of Q2 and thus reduce the uncertainties in the extracted pion charge density.
Delaminations in composite plates under transverse static or impact loads
Finn, S.R.
1991-01-01
A method is presented for calculating the locations, shapes, and sizes of delaminations which occur in a fiber reinforced composite plate subjected to transverse static or dynamic (impact) loads. The plate may be simply supported, clamped, or free along its edges. A failure model of the delamination formation was developed. This model was then coupled with a finite element analysis. The model and the finite element analysis were then implemented by a computer code (IMPACT-ST) which can be used to estimate the load at which damage initiates as well as the locations, shapes, and sizes of the delaminations. Test were also performed measuring the geometries of delaminations in Fiberite T300/976 graphite-epoxy, Fiberite IM7/977-2 graphite-toughened epoxy, and ICI APC-2 graphite-PEEK plates subjected to transverse static and impact loads. The data were compared to results of the model and good agreements were found between the measured and calculated delamination lengths and widths.
Multi-injector modeling of transverse combustion instability experiments
NASA Astrophysics Data System (ADS)
Shipley, Kevin J.
Concurrent simulations and experiments are used to study combustion instabilities in a multiple injector element combustion chamber. The experiments employ a linear array of seven coaxial injector elements positioned atop a rectangular chamber. Different levels of instability are driven in the combustor by varying the operating and geometry parameters of the outer driving injector elements located near the chamber end-walls. The objectives of the study are to apply a reduced three-injector model to generate a computational test bed for the evaluation of injector response to transverse instability, to apply a full seven-injector model to investigate the inter-element coupling between injectors in response to transverse instability, and to further develop this integrated approach as a key element in a predictive methodology that relies heavily on subscale test and simulation. To measure the effects of the transverse wave on a central study injector element two opposing windows are placed in the chamber to allow optical access. The chamber is extensively instrumented with high-frequency pressure transducers. High-fidelity computational fluid dynamics simulations are used to model the experiment. Specifically three-dimensional, detached eddy simulations (DES) are used. Two computational approaches are investigated. The first approach models the combustor with three center injectors and forces transverse waves in the chamber with a wall velocity function at the chamber side walls. Different levels of pressure oscillation amplitudes are possible by varying the amplitude of the forcing function. The purpose of this method is to focus on the combustion response of the study element. In the second approach, all seven injectors are modeled and self-excited combustion instability is achieved. This realistic model of the chamber allows the study of inter-element flow dynamics, e.g., how the resonant motions in the injector tubes are coupled through the transverse pressure
Effect of Centrifugal Transverse Wakefield for Microbunch in Bend
Stupakov, G.V.; /SLAC
2006-03-22
We calculate centrifugal force for a short bunch in vacuum moving in a circular orbit and estimate the emittance growth of the beam in a bend due to this force. Many of the basic features of the coherent synchrotron radiation (CSR) of short bunches and its effect on beam dynamics in accelerators are now well established. The effect is usually described in terms of the longitudinal force, or wakefield, that causes the energy loss in the beam, and also redistributes the energy between the particles by accelerating the head and decelerating the tail of the bunch. Coherent radiation becomes most important for short bunches and high currents. More subtle features of CSR such as transition effect due to the entrance to and exit from the bend, CSR force in the undulator, and shielding due to the close metallic boundaries have been also studied. Much less is known about the transverse force in a short bunch moving on a circular orbit. The problem has been treated in several papers beginning from R. Talman's work, who pointed out that the centrifugal force of a rotating bunch can result in a noticeable tune shift of betatron oscillations. Later, an important correction to the Talman paper has been added, where it was shown that due to the energy variation in the bunch, the effect of the transverse force proportional to R{sup -1} is canceled, and the residual effect is of the order of R{sup -2}, that is much smaller than originally predicted. Recently, however, Derbenev and Shiltsev found the centrifugal force of the order of R{sup -1} that differs from Talman's result by a logarithmic factor only. Taking into account the existing controversy in the literature, in this paper, we consider the transverse force in a bunch based on simple physical arguments, starting from a dc beam. We will derive the centrifugal force for a relativistic coasting beam in vacuum, and then generalize the result for a short bunch, and estimate its effect on the emittance growth in a bend
Blyuss, K B; Bridges, T J; Derks, G
2003-05-01
The stability properties of line solitary wave solutions of the (2+1)-dimensional Boussinesq equation with respect to transverse perturbations and their consequences are considered. A geometric condition arising from a multisymplectic formulation of this equation gives an explicit relation between the parameters for transverse instability when the transverse wave number is small. The Evans function is then computed explicitly, giving the eigenvalues for the transverse instability for all transverse wave numbers. To determine the nonlinear and long-time implications of the transverse instability, numerical simulations are performed using pseudospectral discretization. The numerics confirm the analytic results, and in all cases studied, the transverse instability leads to collapse.
Transverse Single Spin and Azimuthal Asymmetries in Hadronic Collisions at STAR
NASA Astrophysics Data System (ADS)
Vossen, Anselm
2015-01-01
Hadronic collisions with transversely polarized protons are an important part of the quest to understand the transverse spin structure of the proton. Experiments at RHIC collected large datasets at center of mass energies of 200 GeV and 500 GeV, accessing a kinematic regime where factorization is expected to hold. The STAR detector at RHIC, due to its azimuthal symmetry, particle identification capabilities and large acceptance compared with other experiments with polarized protons, is in a unique position to study transverse spin phenomena in p + p↑. This contribution will highlight measurements of transversity using di-hadron correlations, transverse single spin asymmetries in jets, measurements sensitive to the origins of the large single spin asymmetries measured in the forward direction, transverse spin asymmetries in W production, which are sensitive to modified universality effects of Sivers function as well as short and long-term upgrades at STAR.
Explanation for the transverse radiation force observed on a vertically hanging fiber
NASA Astrophysics Data System (ADS)
Brevik, Iver
2014-02-01
As shown in the experiment of She et al. [Phys. Rev. Lett. 101, 243601 (2008), 10.1103/PhysRevLett.101.243601], a weak laser beam sent through a vertically hanging fiber exerts a transverse force and produces a lateral displacement of the fiber's lower end. The experiment is of obvious theoretical interest in connection with the electromagnetic theory of media. Suggested explanations given for this effect in the past include the famous Abraham-Minkowski issue concerning the "correct" photon momentum in matter. In our opinion such an explanation is most likely not right. Instead, we propose a very simple description of the effect implying that the sideways deflection is caused by the radiation force on the obliquely cut lower end face of the fiber. From a calculation based upon geometrical optics, we find quite good agreement with the observations. We present also, as an alternative approach, a calculation involving wave optics instead of geometrical optics, and find comparable results.
Direct Numerical Simulation of Turbulent Pipe Flows subjected to Transverse Oscillations
NASA Astrophysics Data System (ADS)
Czajkowski, Mark; Desjardins, Olivier
2009-11-01
Fundamental effects of transverse oscillations on a turbulent pipe are being studied using direct numerical simulations (DNS). Previous studes of pipes subjected to oscillations around their central axis have shown a reduction in pressure drop. This study is a generalization of previous work to the case of an oscillation around an axis parallel to but not coinciding with the pipe centerline.The role of oscillation frequency, amplitude, and radius on the statistics of turbulent pipe flows, as well as bulk properties like pressure drop are investigated. Two key non-dimensional numbers are identified. The first relates the oscillation amplitude to a turbulent length scale (Taylor micro-scale); and the second number, a Strouhal number, compares the oscillation frequency to a turbulent time scale. These non-dimensional numbers, along with oscillation radius, are varied over a range of values, and DNS were performed using the arbitrarily high order accurate code NGA [Desjardins, et al., JCP 2008]. The resulting turbulent flows were analysed using a variety of turbulent statistics and compared to stationary and pipes rotating around their central axis.
Quantum Quench Dynamics in the Transverse Field Ising Model at Non-zero Temperatures
NASA Astrophysics Data System (ADS)
Abeling, Nils; Kehrein, Stefan
The recently discovered Dynamical Phase Transition denotes non-analytic behavior in the real time evolution of quantum systems in the thermodynamic limit and has been shown to occur in different systems at zero temperature [Heyl et al., Phys. Rev. Lett. 110, 135704 (2013)]. In this talk we present the extension of the analysis to non-zero temperature by studying a generalized form of the Loschmidt echo, the work distribution function, of a quantum quench in the transverse field Ising model. Although the quantitative behavior at non-zero temperatures still displays features derived from the zero temperature non-analyticities, it is shown that in this model dynamical phase transitions do not exist if T > 0 . This is a consequence of the system being initialized in a thermal state. Moreover, we elucidate how the Tasaki-Crooks-Jarzynski relation can be exploited as a symmetry relation for a global quench or to obtain the change of the equilibrium free energy density. This work was supported through CRC SFB 1073 (Project B03) of the Deutsche Forschungsgemeinschaft (DFG).
Transverse-electron-momentum distribution in pump-probe sequential double ionization
NASA Astrophysics Data System (ADS)
Kheifets, A. S.; Ivanov, I. A.
2014-09-01
We study the transverse-electron-momentum distribution (TEMD) of the wave packets launched in a pump-probe sequential double ionization from the valence shell of a noble gas atom. Our calculations, based on an accurate numerical solution of the time-dependent Schrödinger equation (TDSE), reproduce a characteristic cusp of the TEMD which is attributed to the Coulomb singularity. The evolution of the TEMD with the time delay between the pump and probe pulses is shown to be similar to the prediction of the standard tunneling formula (TF), as was observed experimentally for argon by Fechner et al. [Phys. Rev. Lett. 112, 213001 (2014), 10.1103/PhysRevLett.112.213001]. However, TDSE calculations show a clear deviation from the TF and predict a much more complicated structure which cannot be reproduced by the target orbital momentum profile filtered by the tunneling Gaussian. The accuracy of the TF can be improved if the target momentum profile is calculated with the Coulomb waves instead of the plane waves.
Reverse time migration in tilted transversely isotropic media
Zhang, Linbing; Rector III, James W.; Hoversten, G. Michael
2004-07-01
This paper presents a reverse time migration (RTM) method for the migration of shot records in tilted transversely isotropic (TTI) media. It is based on the tilted TI acoustic wave equation that was derived from the dispersion relation. The RTM is a full depth migration allowing for velocity to vary laterally as well as vertically and has no dip limitations. The wave equation is solved by a tenth-order finite difference scheme. Using 2D numerical models, we demonstrate that ignoring the tilt angle will introduce both lateral and vertical shifts in imaging. The shifts can be larger than 0.5 wavelength in the vertical direction and 1.5 wavelength in the lateral direction.
Parameters of a dye laser with transverse pumping
Burakov, V.S.; Samson, A.M.; Zhukovskii, V.V.; Isaevich, A.V.
1987-12-01
The authors describe a new method for determining the excitation and output parameters of dye laser media under conditions of transverse optical pumping by laser radiation. The dye is modeled as a medium with two electron-vibrational levels. The method is based on the variation of the value of the distance on the mirror reflection coefficients of the resonator and on estimates of inactive or parasitic losses, the probability of exciting active dye molecules with the radiation incident on the front face of the cell, and the unsaturated gain coefficient of that output frequency. Experimental data are then derived for these conditions for a rhodamine 4C solution in ethanol. Pumping was done using a neodymium laser.
Rapidity dependence of the average transverse momentum in hadronic collisions
NASA Astrophysics Data System (ADS)
Durães, F. O.; Giannini, A. V.; Gonçalves, V. P.; Navarra, F. S.
2016-08-01
The energy and rapidity dependence of the average transverse momentum
General constitutive model for supercooled liquids: anomalous transverse wave propagation.
Mizuno, Hideyuki; Yamamoto, Ryoichi
2013-03-01
A transverse acoustic wave propagates through supercooled liquids in an anomalous manner: for a macroscopic wave number k, the wave propagates long distances, as in elastic solids, whereas it attenuates rapidly for a mesoscopic to microscopic wave number k, as in viscous liquids. In this work, we theoretically describe this anomalous wave propagation using the hydrodynamics of the two-mode Maxwell constitutive model, which were determined independently from the mechanical properties under oscillatory shear strains. To ensure that the Maxwell model can be applied down to a microscopic length scale, we extended it to a k-dependent equation, taking into account the recently reported k dependences of the shear viscosity and modulus [A. Furukawa and H. Tanaka, Phys. Rev. Lett. 103, 135703 (2009); A. Furukawa H. Tanaka Phys. Rev. E 84, 061503 (2011)]. The anomalous wave propagation in supercooled liquids can also be understood in terms of a linear coupling of many independent normal modes, as in amorphous solids. PMID:23496725
Larmor frequency dressing by a nonharmonic transverse magnetic field
NASA Astrophysics Data System (ADS)
Bevilacqua, G.; Biancalana, V.; Dancheva, Y.; Moi, L.
2012-04-01
We present a theoretical and experimental study of spin precession in the presence of both a static and an orthogonal oscillating magnetic field, which is nonresonant, not harmonically related to the Larmor precession, and of arbitrary strength. Due to the intrinsic nonlinearity of the system, previous models that account only for the simple sinusoidal case cannot be applied. We suggest an alternative approach and develop a model that closely agrees with experimental data produced by an optical-pumping atomic magnetometer. We demonstrate that an appropriately designed nonharmonic field makes it possible to extract a linear response to a weak dc transverse field, despite the scalar nature of the magnetometer, which normally causes a much weaker, second-order response.
Transverse myelitis caused by hepatitis E: previously undescribed in adults.
Sarkar, Pamela; Morgan, Catherine; Ijaz, Samreen
2015-01-01
We report the case of a 62-year-old Caucasian woman who was admitted with urinary retention and lower limb paraesthesia following a week's prodromal illness of headache and malaise. Liver function tests showed a picture of acute hepatocellular dysfunction. She developed reduced lower limb power, brisk reflexes, extensor plantars, a sensory level at T8 and reduced anal sphincter tone, establishing a clinical diagnosis of transverse myelitis. A spinal MRI showed no evidence of cauda equina or spinal cord compression. Cerebrospinal fluid (CSF) analysis showed raised protein and raised white cell count. Hepatitis E IgM and IgG were positive and hepatitis E virus was found in her CSF. She was treated with methylprednisolone and is slowly recovering with physiotherapy. PMID:26150621
Propagation of transverse waves in a radially expanding plasma
NASA Technical Reports Server (NTRS)
Solodyna, C. V.; Belcher, J. W.
1974-01-01
Investigation of the properties of low-frequency transverse waves in an expanding plasma. The wave vector, the background magnetic field, and the streaming velocity of the plasma are all assumed to lie along the radial direction. Expressions are presented for the radial dependence of the amplitude and phase of left and right circularly polarized waves, correct to first order in the wave frequency divided by the proton cyclotron frequency. Differences in the phase velocities of these two circular polarizations result in a Faraday rotation that can be substantial for typical interplanetary conditions near 1 AU. The implications of these results for a realistic solar wind model with the interplanetary magnetic field along the spiral direction are also considered.
A refined nonlinear theory of plates with transverse shear deformation
NASA Technical Reports Server (NTRS)
Reddy, J. N.
1984-01-01
A higher-order shear deformation theory of plates accounting for the von Karman strains is presented. The theory contains the same dependent unknowns as in the Hencky-Mindlin type first-order shear deformation theory and accounts for parabolic distribution of the transverse shear strains through the thickness of the plate. Exact solutions of simply supported plates are obtained using the linear theory and the results are compared with the exact solutions of three-dimensional elasticity theory, the first order shear deformation theory, and the classical plate theory. The present theory predicts the deflections, stresses, and frequencies more accurately when compared to the first-order theory and the classical plate theory.
Direct Optical Probing of Transverse Electric Mode in Graphene
Menabde, Sergey G.; Mason, Daniel R.; Kornev, Evgeny E.; Lee, Changhee; Park, Namkyoo
2016-01-01
Unique electrodynamic response of graphene implies a manifestation of an unusual propagating and localised transverse-electric (TE) mode near the spectral onset of interband transitions. However, excitation and further detection of the TE mode supported by graphene is considered to be a challenge for it is extremely sensitive to excitation environment and phase matching condition adherence. Here for the first time, we experimentally prove an existence of the TE mode by its direct optical probing, demonstrating significant coupling to an incident wave in electrically doped multilayer graphene sheet at room temperature. We believe that proposed technique of careful phase matching and obtained access to graphene’s TE excitation would stimulate further studies of this unique phenomenon, and enable its potential employing in various fields of photonics as well as for characterization of graphene. PMID:26898892
Injection Related Background due to the Transverse Feedback
Decker, F.J.; Akre, R.; Fisher, A.; Iverson, R.; Weaver, M.; /SLAC
2008-03-18
The background in the BaBar detector is especially high during injection, when most components are actually having reduced voltages. The situation is worse for the beam in High Energy Ring (HER) when the LER beam is present. It was found that the transverse feedback system plays an important role when stacking more charge on top of existing bunches. Lowering the feedback gain helped and it was realized later that the best scenario would be to gate off the feedback for only the one bunch, which got additional charge injected into it. The explanation is that the blown-up, but centered, original HER bunch plus the small injected off-axis bunch (each with half the charge) would stay in the ring if not touched, but the feedback system sees half the offset and wants to correct it, therefore disturbing and scraping the blown-up part.
Transverse feedback in a 100 TeV storage ring
Lambertson, G.
1992-06-01
The general purpose for a transverse feedback system in the proton collider is to stabilize coherent bunch motions and reduce them to a small amplitude that will result in an acceptable diffusion rate into incoherent motion. Strong instabilities are expected to be caused by the resistive-wall impedance of the beam tubes in pulsed magnets at the low revolution frequency. The feedback must stabilize thousands of coupled-bunch modes. It must also damp excursions of the injected beam and suppress excitations from noise in magnetic fields, in support structures, and in the feedback circuits. It may also be important in combating some beam-beam interaction effects. Damping by synchrotron radiation will be important in the long-term evolution of the emittance, but it is too weak to be a factor in the coherent damping.
Transverse acoustic trapping using a Gaussian focused ultrasound
Lee, Jungwoo; Teh, Shia-Yen; Lee, Abraham; Kim, Hyung Ham; Lee, Changyang; Shung, K. Kirk
2009-01-01
The optical tweezer has become a popular device to manipulate particles in nanometer scales, and to study the underlying principles of many cellular or molecular interactions. Theoretical analysis was previously carried out at the authors’ laboratory, to show that similar acoustic trapping of microparticles may be possible with a single beam ultrasound. This paper experimentally presents the transverse trapping of 125 μm lipid droplets under an acoustically transparent mylar film, which is an intermediate step toward achieving acoustic tweezers in 3D. Despite the lack of axial trapping capability in the current experimental arrangement, it was found that a 30 MHz focused beam could be used to laterally direct the droplets towards the focus. The spatial range within which acoustic traps may guide droplet motion was in the range of hundreds of micrometers, much greater than that of optical traps. This suggests that this acoustic device may offer an alternative for manipulating microparticles in a wider spatial range. PMID:20045590
Transverse momentum-dependent parton distribution functions in lattice QCD
Engelhardt, Michael G.; Musch, Bernhard U.; Haegler, Philipp G.; Negele, John W.; Schaefer, Andreas
2013-08-01
A fundamental structural property of the nucleon is the distribution of quark momenta, both parallel as well as perpendicular to its propagation. Experimentally, this information is accessible via selected processes such as semi-inclusive deep inelastic scattering (SIDIS) and the Drell-Yan process (DY), which can be parametrized in terms of transversemomentum-dependent parton distributions (TMDs). On the other hand, these distribution functions can be extracted from nucleon matrix elements of a certain class of bilocal quark operators in which the quarks are connected by a staple-shaped Wilson line serving to incorporate initial state (DY) or final state (SIDIS) interactions. A scheme for evaluating such matrix elements within lattice QCD is developed. This requires casting the calculation in a particular Lorentz frame, which is facilitated by a parametrization of the matrix elements in terms of invariant amplitudes. Exploratory results are presented for the time-reversal odd Sivers and Boer-Mulders transverse momentum shifts.
Fast Electronics for the Dafne Transverse Feedback Systems
NASA Astrophysics Data System (ADS)
Drago, Alessandro
Transverse feedback systems for controlling the vertical coupled-bunch instabilities in the positron and electron main rings are installed at DAFNE. They started to be operative respectively from June and September 2000. For the horizontal plane, similar systems have been installed in summer 2001 with less kicker power. Design specifications and the basic system concepts are presented. Real time bunch-by-bunch offset correction is implemented using digital signal processors and dual-port RAM's. Fast analog to digital sampling is performed at the maximum bunch frequency (368 MHz). The system manages at full speed a continuous flow of 8-bits data and it has the capability to invert the sign or put to zero the output for any combination of bunches. A conversion from digital to analog produces the output correcting signal.
Prediction of residual tensile strength of transversely impacted composite laminates
NASA Technical Reports Server (NTRS)
Lal, K. M.
1982-01-01
The response to low velocity impact of graphite-epoxy T300/5208 composite laminates is discussed. Steel balls of 3/8 inch, 5/8 inch, and 1 inch diameter were the projectiles. Impact energy was limited to 1.2 joules. Impacted specimens were ultrasonically C scanned to determine the impact damaged region. The threshold value of impact energy for impact damage was found to be approximately 0.3 joules. A model was developed to predict the tensile residual strength of impact damaged specimens from fracture mechanics concepts. Impacted specimens were tested in tension to provide a fracture data base. The experimental results agreed well with the predictions from fracture mechanics. In this study, the maximum impact velocity used to simulate the low velocity transverse impact from common objects like tool drops was 10 m/s.
Ultra-broadband carpet cloak for transverse-electric polarization
NASA Astrophysics Data System (ADS)
Deng, Ye; Xu, Su; Zhang, Runren; Zheng, Bin; Chen, Hua; Gao, Fei; Yu, Faxin; Zhang, Baile; Chen, Hongsheng
2016-04-01
Magnetism is a necessity in constructing macroscopic metamaterial invisibility cloaks that are theoretically designed by transformation optics, but will generally limit the cloaking bandwidth to an impractically narrow range. To meet the broad bandwidth demand, magnetism has been fully abandoned in previous demonstrations of macroscopic carpet cloaking, whose approach, however, cannot apply to a transverse-electric (TE) polarization. To fill this gap, here we experimentally demonstrate an ultra-broadband magnetic carpet cloak for the TE polarization. The cloak is made of non-resonant closed-ring metamaterials with little dispersion and the cloaking performance is confirmed with both time-domain simulation and frequency scanning measurement over a broad bandwidth corresponding to a pulse signal illumination.
Degeneracy in carbon nanotubes under transverse magnetic δ-fields.
Kuru, Ş; Negro, J; Tristao, S
2015-07-22
The aim of this article was to study the degeneracy of the energy spectrum in a nanotube under a transverse magnetic field. The massless Dirac-Weyl equation has been used to describe the low energy states of this system. The particular case of a singular magnetic field approximated by Dirac delta distributions is considered. It is shown that, under general symmetry conditions, there is a double degeneracy corresponding to periodic solutions with null axial momentum k(z)=0. Also, there may be a kind of sporadic degeneracy for non-vanishing values of k(z), which are explicitly computed in the present example. The proof of these properties is obtained by means of the supersymmetric structure of the Dirac-Weyl Hamiltonian. PMID:26102328
Transverse electromagnetic horn antenna with resistively-loaded exterior surfaces
Aurand, J.F.
1999-09-28
An improved transverse electromagnetic (TEM) horn antenna comprises a resistive loading material on the exterior surfaces of the antenna plates. The resistive loading material attenuates or inhibits currents on the exterior surfaces of the TEM horn antenna. The exterior electromagnetic fields are of opposite polarity in comparison to the primary and desired interior electromagnetic field, thus inherently cause partial cancellation of the interior wave upon radiation or upon reception. Reducing the exterior fields increases the radiation efficiency of the antenna by reducing the cancellation of the primary interior field (supported by the interior surface currents). This increases the transmit gain and receive sensitivity of the TEM horn antenna, as well as improving the transient (time-domain) response.
Transverse glow discharges in supersonic air and methane flows
Denisova, N. V.; Postnikov, B. V.; Fomin, V. M.
2006-03-15
Transverse glow discharges in supersonic air and methane flows are studied both experimentally and theoretically. The experiments show that a diffuse volume discharge filling the whole cross section of the flow can easily be initiated in air, whereas a diffuse discharge in a methane flow shows a tendency to transition into a constricted mode. The electron transport coefficients (mobility and drift velocity) and the kinetic coefficients (such as collisional excitation rates of the vibrational levels of a methane molecule, as well as dissociation and ionization rates) are calculated by numerically solving the Boltzmann equation for the electron energy distribution function. The calculated coefficients are used to estimate the parameters of the plasma and the electric field in the positive column of a discharge in methane.
Nonlinear stability of Halley comethosheath with transverse plasma motion
NASA Technical Reports Server (NTRS)
Srivastava, Krishna M.; Tsurutani, Bruce T.
1994-01-01
Weakly nonlinear Magneto Hydrodynamic (MHD) stability of the Halley cometosheath determined by the balance between the outward ion-neutral drag force and the inward Lorentz force is investigated including the transverse plasma motion as observed in the flanks with the help of the method of multiple scales. The eigenvalues and the eigenfunctions are obtained for the linear problem and the time evolution of the amplitude is obtained using the solvability condition for the solution of the second order problem. The diamagnetic cavity boundary and the adjacent layer of about 100 km thickness is found unstable for the travelling waves of certain wave numbers. Halley ionopause has been observed to have strong ripples with a wavelength of several hundred kilometers. It is found that nonlinear effects have stabilizing effect.
Transverse vibration of trapezoidal plates of variable thickness - Symmetric trapezoids
NASA Astrophysics Data System (ADS)
Liew, K. M.; Lim, M. K.
1993-07-01
A set of simple 2D polynomial functions is employed as the admissible displacement function in the Rayleigh-Ritz energy approach for the free transverse vibration analysis of symmetric trapezoidal plates with linearly varying thickness. The admissible function consists the product of a 2D polynomial function and a basic function defined by the product of the equations of the prescribed continuous piecewise boundary shape, each raised to the power of 0, 1 or 2 (corresponding to a free, simply supported, or clamped edge, respectively). The set of functions generated ensures the satisfaction of all the kinematic boundary conditions at the outset. The proposed method is applied to solve several symmetric trapezoidal plates with different combinations of boundary conditions and variable thickness. The results, for some cases, are compared with the available published values from the open literature. These new results may serve as benchmark data for the development of other numerical methods.
Graded nonintersecting transverse incisions for correction of idiopathic astigmatism.
Thornton, S P; Sanders, D R
1987-01-01
We present the results of a consecutive series of graded transverse (T) incisions for correcting idiopathic astigmatism evaluated by vector analysis, a method not previously used to report T-incision results. In fact, no clinical studies on the results of the T-incision method have been reported. For comparison with conventional reporting methods, the results of graded T incisions on a series of eyes were evaluated, using both vector analysis and simplified analytic procedures. Sixty eyes were evaluated following surgery based on the Thornton guide for astigmatism correction. The mean preoperative cylinder in the series was 1.5 diopters (D) (SD = 0.43, range 1.00 D to 2.25 D); mean postoperative cylinder was 0.4 D (SD = 0.61, range 0 to 3.75 D). The mean decrease of 1.1 D was statistically significant. The results show that it is possible to quantify astigmatism correction using vector analysis. PMID:3559948
Beam dynamics studies for transverse electromagnetic mode type rf deflectors
Ahmed, Shahid; Krafft, Geoffrey A.; Deitrick, Kirsten; De Silva, Subashini U.; Delayen, Jean R.; Spata, Mike; Tiefenback, Michael; Hofler, Alicia; Beard, Kevin
2012-02-14
We have performed three-dimensional simulations of beam dynamics for transverse electromagnetic mode (TEM) type rf deflectors: normal and superconducting. The compact size of these cavities as compared to the conventional TM110 type structures is more attractive particularly at low frequency. Highly concentrated electromagnetic fields between the parallel bars provide strong electrical stability to the beam for any mechanical disturbance. An array of six 2-cell normal conducting cavities or a single cell superconducting structure is enough to produce the required vertical displacement at the target point. Both the normal and superconducting structures show very small emittance dilution due to the verticalmore » kick of the beam.« less
Transverse electromagnetic horn antenna with resistively-loaded exterior surfaces
Aurand, John F.
1999-01-01
An improved transverse electromagnetic (TEM) horn antenna comprises a resistive loading material on the exterior surfaces of the antenna plates. The resistive loading material attenuates or inhibits currents on the exterior surfaces of the TEM horn antenna. The exterior electromagnetic fields are of opposite polarity in comparison to the primary and desired interior electromagnetic field, thus inherently cause partial cancellation of the interior wave upon radiation or upon reception. Reducing the exterior fields increases the radiation efficiency of the antenna by reducing the cancellation of the primary interior field (supported by the interior surface currents). This increases the transmit gain and receive sensitivity of the TEM horn antenna, as well as improving the transient (time-domain) response.
Axial and transverse characterizations of ceramic candle filters
Chen, S.-E.; Nishihama, Y.; Yue, P.C.
2008-09-01
Ceramic candle filters are stiff composite tubes used in particle-removal during hot-gas filtration in coal energy generation. These filters are designed to withstand high temperature and pressure gradients. To determine the consistency in manufactured qualities of these filters, dynamic characterization method is recommended as a nondestructive evaluation technique. Six filters of the same manufactured batch were tested dynamically to establish the baseline properties of these filters. The test results are compared to theoretical values and are used to identify the variation in the manufactured products. This paper reports the frequencies in both transverse and axial directions indicating acceptable variations between all filters that are compatible to variations in measured physical parameters including density, stiffness and elastic modulus.
Transversely isotropic poroelasticity arising from thin isotropic layers
Berryman, J.G.
1996-11-01
Percolation phenomena play central roles in the field of poroelasticity, where two distinct sets of percolating continua intertwine. A connected solid frame forms the basis of the elastic behavior of a poroelastic medium in the presence of confining forces, while connected pores permit a percolating fluid (if present) to influence the mechanical response of the system from within. The present paper discusses isotropic and anisotropic poroelastic media and establishes general formulas for the behavior of transversely isotropic poroelasticity arising from laminations of isotropic components. The Backus averaging method is shown to provide elementary means of constructing general formulas. The results for confined fluids are then compared with the more general Gassmann formulas that must be satisfied by any anisotropic poroelastic medium and found to be in complete agreement.
Single-knob beam line for transverse emittance partitioning
NASA Astrophysics Data System (ADS)
Xiao, C.; Kester, O. K.; Groening, L.; Leibrock, H.; Maier, M.; Rottländer, P.
2013-04-01
Flat beams feature unequal emittances in the horizontal and vertical phase space. Such beams were created successfully in electron machines by applying effective stand-alone solenoid fringe fields in the electron gun. Extension of this method to ion beams was proposed conceptually. The present paper is on the decoupling capabilities of an ion beam emittance transfer line. The proposed beam line provides a single-knob tool to partition the horizontal and vertical rms emittances, while keeping the product of the two emittances constant as well as the transverse rms Twiss parameters (αx,y and βx,y) in both planes. It is shown that this single knob is the solenoid field strength.
Transverse Field Perturbation For PIP-II SRF Cavities
Berrutti, Paolo; Khabiboulline, Timergali N.; Lebedev, Valeri; Yakovlev, Vyacheslav P.
2015-06-01
Proton Improvement Plan II (PIP-II) consists in a plan for upgrading the Fermilab proton accelerator complex to a beam power capability of at least 1 MW delivered to the neutrino production target. A room temperature section accelerates H⁻ ions to 2.1 MeV and creates the desired bunch structure for injection into the superconducting (SC) linac. Five cavity types, operating at three different frequencies 162.5, 325 and 650 MHz, provide acceleration to 800 MeV. This paper presents the studies on transverse field perturbation on particle dynamic for all the superconducting cavities in the linac. The effects studied include quadrupole defocusing for coaxial resonators, and dipole kick due to couplers for elliptical cavities. A multipole expansion has been performed for each of the cavity designs including effects up to octupole.
Electromagnetic envelope solitary waves with transverse perturbation in a plasma
Borhanian, J.
2013-04-15
The system of fluid-Maxwell equations governing the two-dimensional dynamics of electromagnetic waves in a plasma is analyzed by means of multiple scale perturbation method. It is shown that the evolution of the amplitude of wave field is governed by a two-dimensional nonlinear Schroedinger equation. The stability of bright envelope solitons is studied using the variational method. It is found that the development of transverse periodic perturbations on bright solitons is faster for a plasma with near critical density. Dynamics of electromagnetic bright solitons is investigated in the long-wave approximation. Our model predicts the appearance of collapse of electromagnetic waves in plasmas and describes the collapse dynamics at initial stages.
Wagging the contact line: transverse and longitudinal waves.
Saritha, S; Neogi, P
2006-02-14
Kinetics of wetting has been explored where the contact line not only sees a steady spreading but also has longitudinal or transverse oscillations imposed on it. The latter case is realized when spreading takes place over a rough surface. The effects of the imposed motion are small, which seem to be due to low spreading rates and small dynamic contact angles used in this study. However, a singularity is seen in viscous dissipation during the movement on the model rough surface, which is interpreted here as an instability that is similar to Haines' jumps and stick-slip phenomena, with possible entrainment of the displaced fluid. This is the first time that all of these have been associated with each other.
First observation of the exchange of transverse and longitudinal emittances
Ruan, J.; Johnson, A.S.; Lumpkin, A.H.; Thurman-Keup, R.; Edwards, H.; Fliller, R.P.; Koeth, T.; Sun, Y.-E; /Fermilab
2011-02-01
An experimental program to demonstrate a novel phase space manipulation in which the horizontal and longitudinal emittances of a particle beam are exchanged has been completed at the Fermilab A0 Photoinjector. A new beamline, consisting of a TM{sub 110} deflecting mode cavity flanked by two horizontally dispersive doglegs has been installed. We report on the first direct observation of transverse and longitudinal emittance exchange: {l_brace}{var_epsilon}{sub x}{sup n}, {var_epsilon}{sub y}{sup n}, {var_epsilon}{sub z}{sup n}{r_brace} = {l_brace} 2.9 {+-} 0.1, 2.4 {+-} 0.1, 13.1 {+-} 1.3{r_brace} {yields} {l_brace}11.3 {+-} 1.1, 2.9 {+-} 0.5, 3.1 {+-} 0.3{r_brace} mm-mrad.
Extra gonadal sclerosing stromal tumour in the transverse mesocolon.
Mensah, Samuel; Kyei, Ishmael; Ohene-Yeboah, Michael; Adjei, Ernest
2016-03-01
Sclerosing stromal tumour (SST) is a rare benign sex cord stromal tumour of the ovary. We report a case of sclerosing stromal tumour of the mesentery in a 32-year-old Para one who presented with intra abdominal mass, menstrual irregularity and secondary infertility. Histopathology and immunohistochemistry of the completely excised tumour was consistent with sclerosing stromal tumour, immunoreactive only to vimentin. No ovarian tissue was found in the sectioned tumour. Her menses became regular and she conceived 3 months after complete excision and delivered after 9 months. Hormonal assay was not done because SST was least suspected. From literature this is the first case of SST in the transverse mesocolon reported in the West African subregion, and may probably be one of the rare cases of hormonally active SST. PMID:27605726
Simulation study on transverse mode of laser resonator
NASA Astrophysics Data System (ADS)
Zou, H.; Zhou, L. F.; Yang, Z.
2015-08-01
Simulation study of the stability lateral field distribution for a variety of shapes parallel-plane cavity with the Fox-Li numerical iterative method is conducted in this paper, which gives the optical field amplitude distribution and phase distribution after iterating any number of times. After calculation and simulation, we find that the strip cavity needs 245 times iterations to produce a stable field conditions, while rectangular and circular cavity need 103 and 114 times under the same condition. Finally, the user interface for simulating the field distribution of a common parallel-plane cavity is designed, which is conducive to the understanding and extensive application of the theory of laser transverse mode.
NASA Astrophysics Data System (ADS)
Sankarasubramanian, V.; Buitenweg, J. R.; Holsheimer, J.; Veltink, P.
2011-02-01
The aim of this modeling study is to determine the influence of electrode alignment of transverse tripoles on the paresthesia coverage of the pain area in spinal cord stimulation, using a percutaneous triple-lead approach. Transverse tripoles, comprising a central cathode and two lateral anodes, were modeled on the low-thoracic vertebral region (T10-T12) using percutaneous triple-lead configurations, with the center lead on the spinal cord midline. The triple leads were oriented both aligned and staggered. In the staggered configuration, the anodes were offset either caudally (caudally staggered) or rostrally (rostrally staggered) with respect to the midline cathode. The transverse tripolar field steering with the aligned and staggered configurations enabled the estimation of dorsal column fiber thresholds (IDC) and dorsal root fiber thresholds (IDR) at various anodal current ratios. IDC and IDR were considerably higher for the aligned transverse tripoles as compared to the staggered transverse tripoles. The aligned transverse tripoles facilitated deeper penetration into the medial dorsal columns (DCs). The staggered transverse tripoles always enabled broad and bilateral DC activation, at the expense of mediolateral steerability. The largest DC recruited area was obtained with the rostrally staggered transverse tripole. Transverse tripolar geometries, using percutaneous leads, allow for selective targeting of either medial or lateral DC fibers, if and only if the transverse tripole is aligned. Steering of anodal currents between the lateral leads of the staggered transverse tripoles cannot target medially confined populations of DC fibers in the spinal cord. An aligned transverse tripolar configuration is strongly recommended, because of its ability to provide more post-operative flexibility than other configurations.
Relative yield of heavy hadrons as a function of the transverse momentum in LHC experiments
Berezhnoy, A. V.; Likhoded, A. K.
2015-03-15
The relative yield of hadrons involving a b quark (B{sub c}, B{sub s}, B, Ʌ{sub b}, etc.) is studied as a function of the transverse momentum. It is shown that the yields in question exhibit a nontrivial transverse-momentum dependence because of the difference in nonperturbative fragmentation functions and because of the contribution of power-law corrections at low transverse momenta.
Average transverse momentum and energy density in high-energy nucleus-nucleus collisions
NASA Technical Reports Server (NTRS)
Burnett, T. H.; Dake, S.; Fuki, M.; Gregory, J. C.; Hayashi, T.; Holynski, R.; Iwai, J.; Jones, W. V.; Jurak, A.; Lord, J. J.
1986-01-01
Emulsion chambers were used to measure the transverse momenta of photons or pi(0) mesons produced in high-energy cosmic-ray nucleus-nucleus collisions. A group of events having large average transverse momenta has been found which apparently exceeds the expected limiting values. Analysis of the events at early interaction times, of the order of 1 fm/c, indicates that the observed transverse momentum increases with both rapidity density and energy density.
A Critical Analysis of Transverse Dispersivity Field Data
NASA Astrophysics Data System (ADS)
Attinger, Sabine; Zech, Alraune; Bellin, Alberto; Cvetkovic, Vladimir; Dagan, Gedeon; Dietrich, Peter; Fiori, Aldo; Teutsch, Georg
2016-04-01
Spreading of solute plumes in groundwater is often quantified by macrodispersivity. Thereby, the transverse αT and vertical αV characterize the broadening of the plume in the vertical plane, perpendicular to the flow direction. Determining αT and αV from field experiments is difficult and costly. Still, it is an important parameter for making predictions of contaminant transport e.g. for stationary contamination plumes, bio-degradation and natural attenuation. Measured values of αT and αV at field scale are only available for a few sites. Gelhar and coworkers classified in 1992 the values into three reliability groups: highly, moderately and lowly reliable. Only recently, we could show for the longitudinal macrodispersivity αL, that the values of low reliability need to be excluded for further analysis, based on a re-evaluation of the experiments. Furthermore, new studies emerged in the meantime, which requires evaluation of reliability and incorporation, when appropriate. This work focuses on collecting reliable field data of transverse and vertical macrodispersivities. The ensemble of reliable αT and αV values is then used to answer the following questions: (i) Is there an upper limit of αT and αV or the tendency of increasing values with increasing travel distance of tracer plumes? (ii) Can the field data be predicted by theoretical models? (iii) What can we learn from the field based ratios αV/αT and αT/αL? The investigation may provide valuable information for modeling and predicting contaminant transport in groundwater.
Characterization of transverse isotropy in compressed tissue-mimicking phantoms.
Urban, Matthew W; Lopera, Manuela; Aristizabal, Sara; Amador, Carolina; Nenadic, Ivan; Kinnick, Randall R; Weston, Alexander D; Qiang, Bo; Zhang, Xiaoming; Greenleaf, James F
2015-06-01
Tissues such as skeletal muscle and kidneys have well-defined structure that affects the measurements of mechanical properties. As an approach to characterize the material properties of these tissues, different groups have assumed that they are transversely isotropic (TI) and measure the shear wave velocity as it varies with angle with respect to the structural architecture of the organ. To refine measurements in these organs, it is desirable to have tissue-mimicking phantoms that exhibit similar anisotropic characteristics. Some approaches involve embedding fibers into a material matrix. However, if a homogeneous solid is under compression due to a static stress, an acoustoelastic effect can manifest that makes the measured wave velocities change with the compression stress. We propose to exploit this characteristic to demonstrate that stressed tissue mimicking phantoms can be characterized as a TI material. We tested six phantoms made with different concentrations of gelatin and agar. Stress was applied by the weight of a water container centered on top of a plate on top of the phantom. A linear array transducer and a V-1 Verasonics system were used to induce and measure shear waves in the phantoms. The shear wave motion was measured using a compound plane wave imaging technique. Autocorrelation was applied to the received in-phase/quadrature data. The shear wave velocity, c, was estimated using a Radon transform method. The transducer was mounted on a rotating stage so measurements were made every 10° over a range of 0° to 360°, where the stress is applied along 0° to 180° direction. The shear moduli were estimated. A TI model was fit to the data and the fractional anisotropy was evaluated. This approach can be used to explore many configurations of transverse isotropy with the same phantom, simply by applying stress to the tissue-mimicking phantom. PMID:26067038
Transversely isotropic elasticity and poroelasticity arising from thin isotropic layers
Berryman, J.G.
1997-07-01
Since the classic work of Postma [1955] and Backus [1962], much has been learned about elastic constants in vertical transversely isotropic (VTI) media when the anisotropy is due to fine layering of isotropic elastic materials. However, new results are still being discovered. For example, the P-wave anisotropy parameter c{sub 11}/c{sub 33} lies in the range 1/4 {<=} c{sub 11}/c{sub 33} {<=} <{lambda}+2{mu}><1/({lambda}+2{mu})>, when the layers are themselves composed of isotropic elastic materials with Lame constants {lambda} and {mu} and the vertical average of the layers is symbolized by <{center_dot}>. The lower bound corrects a result of Postma. For porous layers, a connected solid frame forms the basis of the elastic behavior of a poroelastic medium in the presence of confining forces, while connected pores permit a percolating fluid (if present) to influence the mechanical response of the system from within. For isotropic and anisotropic poroelastic media, we establish general formulas for the behavior of transversely isotropic poroelasticity arising from laminations of isotropic components. The Backus averaging method is shown to provide elementary means of constructing general formulas. The results for confined fluids are then compared with the more general Gassmann [1951] formulas that must be satisfied by any anisotropic poroelastic medium and found to be in complete agreement. Such results are important for applications to oil exploration using AVO (amplitude versus offset) since the presence or absence of a fluid component, as well as the nature of the fluid, is the critical issue and the ways in which the fluid influences seismic reflection data still need to be better understood.
Studies of the transverse structure of the nucleon at JLab
Mirazita, Marco
2014-03-01
Since the earliest measurements in the '70, hadronic physics deals with a number of surprising phenomena that cannot be explained in the framework of perturbative QCD. Examples are the small fraction of the proton spin carried by the valence quark spins, the persistence at high energies of single spin asymmetries and azimuthal asymmetries in unpolarized processes. It is now believed that the answer to these questions may come from the transverse motion of partons inside the nucleon, which is encoded in the Transverse Momentum Dependent (TMD) Parton Distribution Functions. Among the large variety of processes that can be described in terms of TMDs, a major role is played by Semi-Inclusive Deep Inelastic Scattering (SIDIS) reactions, in which, together with the scattered electron, one or more hadrons are detected in the final state. Single and Double Spin Asymmetries are the experimental observables sensitive to TMDs. The identification of the final hadrons allows the tagging of the quark involved in the reaction at the parton level, and then the flavor separation of the relevant TMDs. SIDIS reactions are studied at Jefferson Laboratories since many years and are one of the main items in the physics program after the upgrade of the CEBAF accelerator. The large amount of new data that will be available in few years calls for the implementation of new tools, such as multidimensional analyses and refined techniques of TMDs extraction from the experimental asymmetries. In this talk, the more recent results obtained at 6 GeV will be shown and the future measurements will be discussed.
Angiotrophic large cell lymphoma mimicking multiple sclerosis associated transverse myelitis.
Ormsby; Prayson; Heard
1999-09-01
Angiotrophic large cell lymphoma (ALCL) is a rare disease characterized by a proliferation of malignant lymphoid cells, usually of B-cell origin, within the lumina of small vessels and frequently involving the central nervous system (CNS). ALCL generally follows a rapidly fatal course and is rarely diagnosed prior to autopsy. Tumour cells are rarely present on examination of peripheral blood, cerebrospinal fluid (CSF) or bone marrow, therefore, an early diagnosis is heavily dependent on recognition of neurological manifestations which are present in over 80% of cases. A pre-mortem diagnosis of ALCL can be made in cases where brain biopsy has been performed. We report a case of a 45-year-old woman demonstrating clinical and laboratory features suggestive of multiple sclerosis associated transverse myelitis (MSA-TM) in whom ALCL was unexpectedly discovered at autopsy. Microscopic examination revealed diffuse CNS vascular involvement by neoplastic cells and prominent myelopathy of the upper thoracic spinal cord associated with ascending and descending tract degeneration of the spinal motor and sensory tracts. Neoplastic cells were immunoreactive for B-cell lymphoid markers. The present case is the first to demonstrate neoplastic B-cell clonality in ALCL using polymerase chain reaction (PCR) to detect abnormal V-D-J immunoglobulin gene rearrangements. ALCL should be considered in the differential diagnosis whenever a transverse myelitis is present in association with global encephalopathy and elevated serum lactate dehydrogenase. The neurological manifestations of ALCL with particular reference to its presentation as MSA-TM is discussed. Copyright 1999 Harcourt Publishers Ltd. PMID:10844781
Characterization of transverse isotropy in compressed tissue-mimicking phantoms.
Urban, Matthew W; Lopera, Manuela; Aristizabal, Sara; Amador, Carolina; Nenadic, Ivan; Kinnick, Randall R; Weston, Alexander D; Qiang, Bo; Zhang, Xiaoming; Greenleaf, James F
2015-06-01
Tissues such as skeletal muscle and kidneys have well-defined structure that affects the measurements of mechanical properties. As an approach to characterize the material properties of these tissues, different groups have assumed that they are transversely isotropic (TI) and measure the shear wave velocity as it varies with angle with respect to the structural architecture of the organ. To refine measurements in these organs, it is desirable to have tissue-mimicking phantoms that exhibit similar anisotropic characteristics. Some approaches involve embedding fibers into a material matrix. However, if a homogeneous solid is under compression due to a static stress, an acoustoelastic effect can manifest that makes the measured wave velocities change with the compression stress. We propose to exploit this characteristic to demonstrate that stressed tissue mimicking phantoms can be characterized as a TI material. We tested six phantoms made with different concentrations of gelatin and agar. Stress was applied by the weight of a water container centered on top of a plate on top of the phantom. A linear array transducer and a V-1 Verasonics system were used to induce and measure shear waves in the phantoms. The shear wave motion was measured using a compound plane wave imaging technique. Autocorrelation was applied to the received in-phase/quadrature data. The shear wave velocity, c, was estimated using a Radon transform method. The transducer was mounted on a rotating stage so measurements were made every 10° over a range of 0° to 360°, where the stress is applied along 0° to 180° direction. The shear moduli were estimated. A TI model was fit to the data and the fractional anisotropy was evaluated. This approach can be used to explore many configurations of transverse isotropy with the same phantom, simply by applying stress to the tissue-mimicking phantom.
Kannan, Usha; Kannan, N.S.; Anbalagan, J.; Rao, Sudha
2014-01-01
Background: The suprascapular notch, a depression on the lateral part of the superior border of the scapula, medial to the coracoid process, is bridged by the superior transverse scapular ligament, which is sometimes ossified and the foramen which is thus completed, transmits the suprascapular nerve to the supraspinatus fossa. Variations in the morphology of suprascapular notch have been identified as one of the causes of suprascapular nerve entrapment. Rengachary et al. classified this notch into six types, based on its shape. Aim of Study: To study morphological variations of suprascapular notch in Indian dry scapulae and to analyze the incidence of completely ossified superior transverse scapular ligament with other ethnic populations which have been cited earlier. Materials and Methods: A total of 400 human dry scapulae which were obtained from the Department of Anatomy of selected eight medical colleges were analyzed. The type of suprascapular notch was noted and it was recorded as per the description given by Rengachary et al. The results of the present study were compared with the results of previous authors in different populations. Results: In our study, out of 400 scapulae, 40 (10%), were identified to have completely ossified superior transverse scapular ligaments. The frequencies of various types of suprascapular notches were: Type I -20%, Type II -10%, Type III -52%, Type IV -4%, Type V -4%, Type VI -10%. Conclusion: Since the suprascapular nerve entrapment syndrome might be caused by complete ossification of superior transverse scapular ligament with formation of suprascapular foramen and other morphometric variations of suprascapular notch, the knowledge on such variations is essential for clinicians, for making a proper diagnosis and for planning the most suitable surgical intervention. PMID:24783065
Continuous Quantum Nondemolition Measurement of the Transverse Component of a Qubit
NASA Astrophysics Data System (ADS)
Vool, U.; Shankar, S.; Mundhada, S. O.; Ofek, N.; Narla, A.; Sliwa, K.; Zalys-Geller, E.; Liu, Y.; Frunzio, L.; Schoelkopf, R. J.; Girvin, S. M.; Devoret, M. H.
2016-09-01
Quantum jumps of a qubit are usually observed between its energy eigenstates, also known as its longitudinal pseudospin component. Is it possible, instead, to observe quantum jumps between the transverse superpositions of these eigenstates? We answer positively by presenting the first continuous quantum nondemolition measurement of the transverse component of an individual qubit. In a circuit QED system irradiated by two pump tones, we engineer an effective Hamiltonian whose eigenstates are the transverse qubit states, and a dispersive measurement of the corresponding operator. Such transverse component measurements are a useful tool in the driven-dissipative operation engineering toolbox, which is central to quantum simulation and quantum error correction.
Effect of twist on transverse impact response of ballistic fiber yarns
Song, Bo; Lu, Wei -Yang
2015-06-15
A Hopkinson bar was employed to conduct transverse impact testing of twisted Kevlar KM2 fiber yarns at the same impact speed. The speed of Euler transverse wave generated by the impact was measured utilizing a high speed digital camera. The study included fiber yarns twisted by different amounts. The Euler transverse wave speed was observed to increase with increasing amount of twist of the fiber yarn, within the range of this investigation. As a result, the higher transverse wave speeds in the more twisted fiber yarns indicate better ballistic performance in soft body armors for personal protection.
Transverse offset loss between two identical noncircular single-mode waveguides
NASA Astrophysics Data System (ADS)
Liang, A. H.; Tsang, H. K.
1995-08-01
We derive an approximation for the transverse offset loss based on the Laplacian mode-field half-width (MFHW) and far-field second moment for two arbitrary identical noncircular single-mode waveguides. The relation is reduced to the known result for circular-symmetric, single-mode waveguides. Numerical results for symmetrical rectangular waveguides show that the transverse offset loss calculated from the Laplacian MFHW is more accurate than that from the elliptical Gaussian MFHW for small transverse offsets. To our knowledge, this is the first calculation of the errors in the approximate transverse offset loss relations derived from the Laplacian and the elliptical Gaussian MFHW for noncircular optical waveguides.
Arregui, I.; Asensio Ramos, A.
2013-06-01
We present a Bayesian seismology inversion technique for propagating magnetohydrodynamic transverse waves observed in coronal waveguides. The technique uses theoretical predictions for the spatial damping of propagating kink waves in transversely inhomogeneous coronal waveguides. It combines wave amplitude damping length scales along the waveguide with theoretical results for resonantly damped propagating kink waves to infer the plasma density variation across the oscillating structures. Provided that the spatial dependence of the velocity amplitude along the propagation direction is measured and the existence of two different damping regimes is identified, the technique would enable us to fully constrain the transverse density structuring, providing estimates for the density contrast and its transverse inhomogeneity length scale.
Collins, J.; Gamberg, L.; Prokudin, A.; Rogers, T. C.; Sato, N.; Wang, B.
2016-08-08
We construct an improved implementation for combining TMD factorization transverse- momentum-dependent (TMD) factorization and collinear factorization. TMD factorization is suit- able for low transverse momentum physics, while collinear factorization is suitable for high transverse momenta and for a cross section integrated over transverse momentum. The result is a modified version of the standard W + Y prescription traditionally used in the Collins-Soper-Sterman (CSS) formalism and related approaches. As a result, we further argue that questions regarding the shape and Q- dependence of the cross sections at lower Q are largely governed by the matching to the Y -term.
Transverse momentum dependent quark distributions and polarized Drell-Yan processes
Zhou, J.; Yuan, F.; Liang, Z.-T.
2009-09-11
We study the spin-dependent quark distributions at large transverse momentum. We derive their transverse momentum behaviors in the collinear factorization approach in this region. We further calculate the angular distribution of the Drell-Yan lepton pair production with polarized beams and present the results in terms of the collinear twist-three quark-gluon correlation functions. In the intermediate transverse momentum region, we find that the two pproaches: the collinear factorization and the transverse momentum dependent factorization approaches are consistent in the description of the lepton pair angular distributions.
Ultrasonic transverse velocity calibration of standard blocks for use in non-destructive testing
NASA Astrophysics Data System (ADS)
Silva, C. E. R.; Braz, D. S.; Maggi, L. E.; Costa Felix, R. P. B.
2015-01-01
Standard blocks are employed in the verification of the equipment used in Ultrasound Non-Destructive Testing. To assure the metrology reliability of all the measurement process, it is necessary to calibrate or certify these Standard blocks. In this work, the transverse wave velocity and main dimensions were assessed according to the specifications ISO Standards. For transverse wave velocity measurement, a 5 MHz transverse wave transducer, a waveform generator, an oscilloscope and a computer with a program developed in LabVIEWTM were used. Concerning the transverse wave velocity calibration, only two Standard blocks of the 4 tested is in accordance with the standard.