WorldWideScience

Sample records for current experimental constraints

  1. SUSY effects in Rb: Revisited under current experimental constraints

    Science.gov (United States)

    Su, Wei; Yang, Jin Min

    2016-06-01

    In this note we revisit the SUSY effects in Rb under current experimental constraints including the LHC Higgs data, the B-physics measurements, the dark matter relic density and direct detection limits, as well as the precision electroweak data. We first perform a scan to figure out the currently allowed parameter space and then display the SUSY effects in Rb. We find that although the SUSY parameter space has been severely restrained by current experimental data, both the general MSSM and the natural-SUSY scenario can still alter Rb with a magnitude sizable enough to be observed at future Z-factories (ILC, CEPC, FCC-ee, Super Z-factory) which produce 109-1012Z-bosons. To be specific, assuming a precise measurement δRb = 2.0 ×10-5 at FCC-ee, we can probe a right-handed stop up to 530 GeV through chargino-stop loops, probe a sbottom to 850 GeV through neutralino-sbottom loops and a charged Higgs to 770 GeV through the Higgs-top quark loops for a large tan ⁡ β. The full one-loop SUSY correction to Rb can reach 1 ×10-4 in natural SUSY and 2 ×10-4 in the general MSSM.

  2. SUSY effects in $R_b$: revisited under current experimental constraints

    CERN Document Server

    Su, Wei

    2016-01-01

    In this note we revisit the effects of natural SUSY in $R_b$ under current experimental constraints including the LHC Higgs data, the $B$-physics measurements, the dark matter relic density and direct detection limits, as well as the precision electroweak data. We first perform a scan to figure out the currently allowed parameter space of natural SUSY and then display the SUSY effects in $R_b$. We find that although the SUSY parameter space has been severely restrained by current experimental data, natural SUSY can still alter $R_b$ with a magnitude sizable enough to be observed at future $Z$-factories (ILC, CEPC, FCC-ee, Super $Z$-factory) which produce $10^9-10^{12}$ $Z$-bosons.

  3. Experimental Constraints on a Vesta Magma Ocean

    Science.gov (United States)

    Hoff, C.; Jones, J. H.; Le, L.

    2014-01-01

    A magma ocean model was devised to relate eucrites (basalts) and diogenites (orthopyroxenites), which are found mixed together as clasts in a suite of polymict breccias known as howardites. The intimate association of eucritic and diogenitic clasts in howardites argues strongly that these three classes of achondritic meteorites all originated from the same planetoid. Reflectance spectral evidence (including that from the DAWN mission) has long suggested that Vesta is indeed the Eucrite Parent Body. Specifically, the magma ocean model was generated as follows: (i) the bulk Vesta composition was taken to be 0.3 CV chondrite + 0.7 L chondrite but using only 10% of the Na2O from this mixture; (ii) this composition is allowed to crystallize at 500 bar until approx. 80% of the system is solid olivine + low-Ca pyroxene; (iii) the remaining 20% liquid crystallizes at one bar from 1250C to 1110C, a temperature slightly above the eucrite solidus. All crystallization calculations were performed using MELTS. In this model, diogenites are produced by cocrystallization of olivine and pyroxene in the >1250C temperature regime, with Main Group eucrite liquids being generated in the 1300-1250C temperature interval. Low-Ca pyroxene reappears at 1210C in the one-bar calculations and fractionates the residual liquid to produce evolved eucrite compositions (Stannern Trend). We have attempted to experimentally reproduce the Vesta magma ocean. In the MELTS calculation, the change from 500 bar to one bar results in a shift of the olivine:low-Ca pyroxene boundary so that the 1250C liquid is now in the olivine field and, consequently, olivine should be the first-crystallizing phase, followed by low-Ca pyroxene at 1210C, and plagioclase at 1170C. Because at one bar the olivine:low-Ca pyroxene boundary is a peritectic, fractional crystallization of the 1210C liquid proceeds with only pyroxene crystallization until plagioclase appears. Thus, the predictions of the MELTS calculation are clear

  4. Combining experimental and cosmological constraints on heavy neutrinos

    Directory of Open Access Journals (Sweden)

    Marco Drewes

    2017-08-01

    Full Text Available We study experimental and cosmological constraints on the extension of the Standard Model by three right handed neutrinos with masses between those of the pion and W boson. We combine for the first time direct, indirect and cosmological constraints in this mass range. This includes experimental constraints from neutrino oscillation data, neutrinoless double β decay, electroweak precision data, lepton universality, searches for rare lepton decays, tests of CKM unitarity and past direct searches at colliders or fixed target experiments. On the cosmological side, big bang nucleosynthesis has the most pronounced impact. Our results can be used to evaluate the discovery potential of searches for heavy neutrinos at LHCb, BELLE II, SHiP, ATLAS, CMS or a future lepton collider.

  5. Selective constraints in experimentally defined primate regulatory regions.

    Directory of Open Access Journals (Sweden)

    Daniel J Gaffney

    2008-08-01

    Full Text Available Changes in gene regulation may be important in evolution. However, the evolutionary properties of regulatory mutations are currently poorly understood. This is partly the result of an incomplete annotation of functional regulatory DNA in many species. For example, transcription factor binding sites (TFBSs, a major component of eukaryotic regulatory architecture, are typically short, degenerate, and therefore difficult to differentiate from randomly occurring, nonfunctional sequences. Furthermore, although sites such as TFBSs can be computationally predicted using evolutionary conservation as a criterion, estimates of the true level of selective constraint (defined as the fraction of strongly deleterious mutations occurring at a locus in regulatory regions will, by definition, be upwardly biased in datasets that are a priori evolutionarily conserved. Here we investigate the fitness effects of regulatory mutations using two complementary datasets of human TFBSs that are likely to be relatively free of ascertainment bias with respect to evolutionary conservation but, importantly, are supported by experimental data. The first is a collection of almost >2,100 human TFBSs drawn from the literature in the TRANSFAC database, and the second is derived from several recent high-throughput chromatin immunoprecipitation coupled with genomic microarray (ChIP-chip analyses. We also define a set of putative cis-regulatory modules (pCRMs by spatially clustering multiple TFBSs that regulate the same gene. We find that a relatively high proportion ( approximately 37% of mutations at TFBSs are strongly deleterious, similar to that at a 2-fold degenerate protein-coding site. However, constraint is significantly reduced in human and chimpanzee pCRMS and ChIP-chip sequences, relative to macaques. We estimate that the fraction of regulatory mutations that have been driven to fixation by positive selection in humans is not significantly different from zero. We also find

  6. NOAA NOS SOS, EXPERIMENTAL - Currents

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA NOS SOS server is part of the IOOS DIF SOS Project. The stations in this dataset have currents data. *These services are for testing and evaluation use...

  7. Top Quark Current Experimental Status

    CERN Document Server

    Juste, A

    2006-01-01

    Ten years after its discovery at the Tevatron collider, we still know little about the top quark. Its large mass suggests it may play a key role in the mechanism of Electroweak Symmetry Breaking (EWSB), or open a window of sensitivity to new physics related to EWSB and preferentially coupled to it. To determine whether this is the case, precision measurements of top quark properties are necessary. The high statistics samples being collected by the Tevatron experiments during Run II start to incisively probe the top quark sector. This report summarizes the experimental status of the top quark, focusing in particular on the recent measurements from the Tevatron.

  8. Current and Future Constraints on Primordial Magnetic Fields

    Science.gov (United States)

    Sutton, Dylan R.; Feng, Chang; Reichardt, Christian L.

    2017-09-01

    We present new limits on the amplitude of potential primordial magnetic fields (PMFs) using temperature and polarization measurements of the cosmic microwave background (CMB) from Planck, the BICEP2/Keck Array, Polarbear, and SPTpol. We reduce twofold the 95% confidence upper limit on the CMB anisotropy power due to a nearly scale-invariant PMF, with an allowed B-mode power at ℓ = 1500 of {D}{\\ell =1500}{BB}< 0.071 μ {K}2 for Planck versus {D}{\\ell =1500}{BB}< 0.034 μ {K}2 for the combined data set. We also forecast the expected limits from soon-to-deploy CMB experiments (like SPT-3G, Adv. ACTpol, or the Simons Array) and the proposed CMB-S4 experiment. Future CMB experiments should dramatically reduce the current uncertainties by one order of magnitude for the near-term experiments and two orders of magnitude for the CMB-S4 experiment. The constraints from CMB-S4 have the potential to rule out much of the parameter space for PMFs.

  9. Experimental constraint on dark matter detection with optical atomic clocks

    Science.gov (United States)

    Wcisło, P.; Morzyński, P.; Bober, M.; Cygan, A.; Lisak, D.; Ciuryło, R.; Zawada, M.

    2016-12-01

    The total mass density of the Universe appears to be dominated by dark matter. However, beyond its gravitational interactions at the galactic scale, little is known about its nature1. Several proposals have been advanced in recent years for the detection of dark matter2-4. In particular, a network of atomic clocks could be used to search for transient indicators of hypothetical dark matter5 in the form of stable topological defects; for example, monopoles, strings or domain walls6. The clocks become desynchronized when a dark-matter object sweeps through the network. This pioneering approach5 requires a comparison between at least two distant optical atomic clocks7-9. Here, by exploiting differences in the susceptibilities of the atoms and the cavity to the fine-structure constant10,11, we show that a single optical atomic clock12 is already sensitive to dark-matter events. This implies that existing optical atomic clocks13,14 can serve as a global topological-defect dark-matter observatory, without any further developments in experimental apparatus or the need for long phase-noise-compensated optical-fibre links15. Using optical atomic clocks, we explored a new dimension of astrophysical observations by constraining the strength of atomic coupling to hypothetical dark-matter cosmic objects. Under the conditions of our experiments, the degree of constraint was found to exceed the previously reported limits16 by more than three orders of magnitude.

  10. Experimental constraints on phase relations in subducted continental crust

    Science.gov (United States)

    Hermann, Jörg

    2002-01-01

    Synthesis piston cylinder experiments were carried out in the range 2.0-4.5 GPa and 680-1,050 °C to investigate phase relations in subducted continental crust. A model composition (KCMASH) has been used because all major ultrahigh-pressure (UHP) minerals of the whole range of rock types typical for continental crust can be reproduced within this system. The combination of experimental results with phase petrologic constraints permits construction of a UHP petrogenetic grid. The phase relations demonstrate that the most important UHP paragenesis consists of coesite, kyanite, phengite, clinopyroxene, and garnet in subducted continental crust. Below 700 °C talc is stable instead of garnet. As most of these minerals are also stable at much lower pressure and temperature conditions it is thus not easy to recognize UHP metamorphism in subducted crust. A general feature, however, is the absence of feldspars at H2O-saturated conditions. Plagioclase is never stable at UHP conditions, but K-feldspar can occur in H2O-undersaturated rocks. Mineral compositions in the experiments are fully buffered by coexisting phases. The Si content of phengite and biotite increase with increasing pressure. At 4.0 GPa, 780 °C, biotite contains 3.28 Si per formula unit, which is most probably caused by solid solution of biotite with talc. Above 800 °C, the CaAl2SiO6 component in clinopyroxene buffered with kyanite, coesite and a Mg-phase increases with increasing temperature, providing a tool to distinguish between 'cold' and 'hot' eclogites. Up to 10% Ca-eskolaite (Ca0.5[]0.5AlSi2O6) in clinopyroxene has been found at the highest temperature and pressure investigated (>900 °C, 4.5 GPa). Garnet buffered with coesite, kyanite and clinopyroxene displays an increase of grossular component with increasing pressure for a given temperature. Although the investigated system represents a simplification with respect to natural rocks, it helps to constrain general features of subducted continental

  11. Special Education Teacher Leadership in Jordan: Current State and Constraints

    Directory of Open Access Journals (Sweden)

    Eman Al-Zboon

    2016-06-01

    Full Text Available Distributed leadership can enhance the professional learning communities of schools. The present study explored the leadership experience of Jordanian special education teachers, and their perceptions of common constraints to leadership. A mixed method design was used, including a survey (n = 136 and an interview (n = 23. Results indicated that special education teachers had little experience of leadership roles. They regarded the provision of cognitive and emotional support to colleagues as their most important leadership role, and participating in interview committees and selecting new teachers as the least important. There were no significant mean differences between male and female special education teachers in their level of enacted leadership. Level of education and years of experience were found to have a significant effect on the level of teachers’ leadership.

  12. Neutral-current constraints on gauge theories. II

    Energy Technology Data Exchange (ETDEWEB)

    Rizzo, T.; Mathur, V.S.

    1978-09-01

    We extend the analysis of our SU(2) x U(1) model to the case of the ambidextrous SU/sub L/(2) x SU(2)/sub R/ x U(1) model and SU(2) x U/sub L/(1) x U/sub R/(1) models of the vector type. In the first case, we find that the only model of this kind that can fit the present neutral-current data is the standard doublet model. In the latter case, we find that vector models are ruled out.

  13. Current LHC constraints on minimal universal extra dimensions

    Science.gov (United States)

    Deutschmann, Nicolas; Flacke, Thomas; Kim, Jong Soo

    2017-08-01

    In this letter, we present LHC limits on the minimal universal extra dimension (MUED) model from LHC Run 1 data and current limits from searches of the ongoing Run 2. Typical collider signals of the Kaluza-Klein (KK) states mimic generic degenerate supersymmetry (SUSY) missing transverse momentum signatures since the KK particles cascade decay into jets, leptons and the lightest KK particle which is stable due to KK parity and evades detection. We test the parameter space against a large number of supersymmetry based missing energy searches implemented in the public code CheckMATE. We demonstrate the complementarity of employing various searches which target a large number of final state signatures, and we derive the most up to date limits on the MUED parameter space from 13 TeV SUSY searches.

  14. Geometrical constraint experimental determination of Raman lidar overlap profile.

    Science.gov (United States)

    Li, Jian; Li, Chengcai; Zhao, Yiming; Li, Jing; Chu, Yiqi

    2016-06-20

    A simple experimental method to determine the overlap profile of Raman lidar is presented in this paper. Based on Mie and Raman backscattering signals and a geometrically constrained condition, the overlap profile of a Raman lidar system can be determined. Our approach simultaneously retrieves the lidar ratio of aerosols, which is one of the most important sources of uncertainty in the overlap profile determination. The results indicate that the overlap factor is significantly influenced by the lidar ratio in experimental methods. A representative case study indicates that the correction of the overlap profile obtained by this method is practical and feasible.

  15. Experimental constraints on the Skaergaard liquid line of descent

    Science.gov (United States)

    Thy, P.; Lesher, C. E.; Nielsen, T. F. D.; Brooks, C. K.

    2006-11-01

    New experimental information permits a forward approach to modeling the liquid line of descent of the Skaergaard intrusion. A series of melting experiments on chilled margins of evolved tholeiitic and ferrobasaltic dikes associated with the intrusion is, in combination with existing data, used to develop quantitative crystallization models that allow liquid and solid compositions to be predicted for initial magma compositions and crystallization conditions open or closed with respect to oxygen. The new experimental results comprise 6 experiments with melts coexisting with plagioclase and olivine, 29 experiments in addition containing augite, 14 experiments in addition containing ilmenite and/or magnetite, and 6 experiments in addition containing pigeonite and sometimes lacking olivine. All melting experiments were done at atmospheric pressure and with a furnace gas mostly controlled to the fayalite-magnetite-quartz oxygen buffer (FMQ). Using these experimental results, the melt evolution can be constrained for the layered series of the Skaergaard intrusion. Fractionation of a LZa troctolitic assemblage drives the residual liquid toward increasing iron with slight increase in silica. The appearance of augite as an abundant mineral phase in the LZb and the fractionation of a gabbroic assemblage adjust the liquid trend to one of slightly decreasing silica with continued strong increase in iron. Silica decline is principally dependent on the crystallization of augite and restricted to LZb. The appearance of Fe-Ti oxide minerals and the fractionation of Fe-Ti oxide gabbroic assemblages in LZc deflect the evolution trends of iron and silica. The modeling based on the experimental results suggests marked LZc-MZ silica enrichment concurrently with increasing iron content until upper MZ and thereafter relatively constant or slightly decreasing iron. The iron concentration level at which the deflection in iron and silica contents occurs is dependent on several factors of

  16. Experimental Constraints of the Exotic Shearing of Space-Time

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, Jonathan William [Univ. of Chicago, IL (United States)

    2016-08-01

    The Holometer program is a search for rst experimental evidence that space-time has quantum structure. The detector consists of a pair of co-located 40-m power-recycled interferometers whose outputs are read out synchronously at 50 MHz, achieving sensitivity to spatiallycorrelated uctuations in dierential position on time scales shorter than the light-crossing time of the instruments. Unlike gravitational wave interferometers, which time-resolve transient geometrical disturbances in the spatial background, the Holometer is searching for a universal, stationary quantization noise of the background itself. This dissertation presents the nal results of the Holometer Phase I search, an experiment congured for sensitivity to exotic coherent shearing uctuations of space-time. Measurements of high-frequency cross-spectra of the interferometer signals obtain sensitivity to spatially-correlated eects far exceeding any previous measurement, in a broad frequency band extending to 7.6 MHz, twice the inverse light-crossing time of the apparatus. This measurement is the statistical aggregation of 2.1 petabytes of 2-byte dierential position measurements obtained over a month-long exposure time. At 3 signicance, it places an upper limit on the coherence scale of spatial shear two orders of magnitude below the Planck length. The result demonstrates the viability of this novel spatially-correlated interferometric detection technique to reach unprecedented sensitivity to coherent deviations of space-time from classicality, opening the door for direct experimental tests of theories of relational quantum gravity.

  17. Experimental Constraints of the Exotic Shearing of Space-Time

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, Jonathan William [Chicago U.

    2016-01-01

    The Holometer program is a search for rst experimental evidence that space-time has quantum structure. The detector consists of a pair of co-located 40-m power-recycled interferometers whose outputs are read out synchronously at 50 MHz, achieving sensitivity to spatiallycorrelated uctuations in dierential position on time scales shorter than the light-crossing time of the instruments. Unlike gravitational wave interferometers, which time-resolve transient geometrical disturbances in the spatial background, the Holometer is searching for a universal, stationary quantization noise of the background itself. This dissertation presents the nal results of the Holometer Phase I search, an experiment congured for sensitivity to exotic coherent shearing uctuations of space-time. Measurements of high-frequency cross-spectra of the interferometer signals obtain sensitivity to spatially-correlated eects far exceeding any previous measurement, in a broad frequency band extending to 7.6 MHz, twice the inverse light-crossing time of the apparatus. This measurement is the statistical aggregation of 2.1 petabytes of 2-byte dierential position measurements obtained over a month-long exposure time. At 3 signicance, it places an upper limit on the coherence scale of spatial shear two orders of magnitude below the Planck length. The result demonstrates the viability of this novel spatially-correlated interferometric detection technique to reach unprecedented sensitivity to coherent deviations of space-time from classicality, opening the door for direct experimental tests of theories of relational quantum gravity.

  18. Experimental Constraints on the Chemical Differentiation of Mercurys Mantle

    Science.gov (United States)

    Boujibar, A.; Righter, K.; Pando, K.; Danielson, L.

    2015-01-01

    Mercury is known as being the most reduced terrestrial planet with the highest core/mantle ratio. Results from MESSENGER spacecraft have shown that its surface is FeO-poor (2-4 wt%) and S-rich (up to 6-7 wt%), which confirms the reducing nature of its silicate mantle. In addition several features suggest important melting stages of the Mercurian mantle: widespread volcanic deposits on its surface, a high crustal thickness (approximately 10% of the planet's volume) and chemical compositions of its surface suggesting several stages of differentiation and remelting processes. Therefore it is likely that igneous processes like magma ocean crystallization and continuous melting have induced chemical and mineralogical heterogeneities in the Mercurian mantle. The extent and nature of compositional variations produced by partial melting remains poorly constrained for the particular compositions of Mercury (very reducing conditions, low FeO-contents and high sulfur-contents). Melting experiments with bulk Mercury-analogue compositions are scarce and with poorly con-trolled starting compositions. Therefore additional experimental data are needed to better understand the differentiation processes that lead to the observed chemical compositions of Mercury's surface.

  19. Experimental constraints on the outgassing dynamics of basaltic magmas

    Science.gov (United States)

    Pioli, L.; Bonadonna, C.; Azzopardi, B. J.; Phillips, J. C.; Ripepe, M.

    2012-03-01

    The dynamics of separated two-phase flow of basaltic magmas in cylindrical conduits has been explored combining large-scale experiments and theoretical studies. Experiments consisted of the continuous injection of air into water or glucose syrup in a 0.24 m diameter, 6.5 m long bubble column. The model calculates vesicularity and pressure gradient for a range of gas superficial velocities (volume flow rates/pipe area, 10-2-102 m/s), conduit diameters (100-2 m), and magma viscosities (3-300 Pa s). The model is calibrated with the experimental results to extrapolate key flow parameters such as Co (distribution parameter) and Froude number, which control the maximum vesicularity of the magma in the column, and the gas rise speed of gas slugs. It predicts that magma vesicularity increases with increasing gas volume flow rate and decreases with increasing conduit diameter, until a threshold value (45 vol.%), which characterizes churn and annular flow regimes. Transition to annular flow regimes is expected to occur at minimum gas volume flow rates of 103-104 m3/s. The vertical pressure gradient decreases with increasing gas flow rates and is controlled by magma vesicularity (in bubbly flows) or the length and spacing of gas slugs. This study also shows that until conditions for separated flow are met, increases in magma viscosity favor stability of slug flow over bubbly flow but suggests coexistence between gas slugs and small bubbles, which contribute to a small fraction of the total gas outflux. Gas flow promotes effective convection of the liquid, favoring magma homogeneity and stable conditions.

  20. Silicic magma differentiation in ascent conduits. Experimental constraints

    Science.gov (United States)

    Rodríguez, Carmen; Castro, Antonio

    2017-02-01

    Crystallization of water-bearing silicic magmas in a dynamic thermal boundary layer is reproduced experimentally by using the intrinsic thermal gradient of piston-cylinder assemblies. The standard AGV2 andesite under water-undersaturated conditions is set to crystallize in a dynamic thermal gradient of about 35 °C/mm in 10 mm length capsules. In the hotter area of the capsule, the temperature is initially set at 1200 °C and decreases by programmed cooling at two distinct rates of 0.6 and 9.6 °C/h. Experiments are conducted in horizontally arranged assemblies in a piston cylinder apparatus to avoid any effect of gravity settling and compaction of crystals in long duration runs. The results are conclusive about the effect of water-rich fluids that are expelled out the crystal-rich zone (mush), where water saturation is reached by second boiling in the interstitial liquid. Expelled fluids migrate to the magma ahead of the solidification front contributing to a progressive enrichment in the fluxed components SiO2, K2O and H2O. The composition of water-rich fluids is modelled by mass balance using the chemical composition of glasses (quenched melt). The results are the basis for a model of granite magma differentiation in thermally-zoned conduits with application of in-situ crystallization equations. The intriguing textural and compositional features of the typical autoliths, accompanying granodiorite-tonalite batholiths, can be explained following the results of this study, by critical phenomena leading to splitting of an initially homogeneous magma into two magma systems with sharp boundaries. Magma splitting in thermal boundary layers, formed at the margins of ascent conduits, may operate for several km distances during magma transport from deep sources at the lower crust or upper mantle. Accordingly, conduits may work as chromatographic columns contributing to increase the silica content of ascending magmas and, at the same time, leave behind residual mushes that

  1. A method for estimating tokamak poloidal field coil currents which incorporates engineering constraints

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, W.A.

    1990-05-01

    This thesis describes the development of a design tool for the poloidal field magnet system of a tokamak. Specifically, an existing program for determining the poloidal field coil currents has been modified to: support the general case of asymmetric equilibria and coil sets, determine the coil currents subject to constraints on the maximum values of those currents, and determine the coil currents subject to limits on the forces those coils may carry. The equations representing the current limits and coil force limits are derived and an algorithm based on Newton's method is developed to determine a set of coil currents which satisfies those limits. The resulting program allows the designer to quickly determine whether or not a given coil set is capable of supporting a given equilibrium. 25 refs.

  2. Invariance in current dipole moment density across brain structures and species: physiological constraint for neuroimaging.

    Science.gov (United States)

    Murakami, Shingo; Okada, Yoshio

    2015-05-01

    Although anatomical constraints have been shown to be effective for MEG and EEG inverse solutions, there are still no effective physiological constraints. Strength of the current generator is normally described by the moment of an equivalent current dipole Q. This value is quite variable since it depends on size of active tissue. In contrast, the current dipole moment density q, defined as Q per surface area of active cortex, is independent of size of active tissue. Here we studied whether the value of q has a maximum in physiological conditions across brain structures and species. We determined the value due to the primary neuronal current (q primary) alone, correcting for distortions due to measurement conditions and secondary current sources at boundaries separating regions of differing electrical conductivities. The values were in the same range for turtle cerebellum (0.56-1.48 nAm/mm(2)), guinea pig hippocampus (0.30-1.34 nAm/mm(2)), and swine neocortex (0.18-1.63 nAm/mm(2)), rat neocortex (~2.2 nAm/mm(2)), monkey neocortex (~0.40 nAm/mm(2)) and human neocortex (0.16-0.77 nAm/mm(2)). Thus, there appears to be a maximum value across the brain structures and species (1-2 nAm/mm(2)). The empirical values closely matched the theoretical values obtained with our independently validated neural network model (1.6-2.8 nAm/mm(2) for initial spike and 0.7-3.1 nAm/mm(2) for burst), indicating that the apparent invariance is not coincidental. Our model study shows that a single maximum value may exist across a wide range of brain structures and species, varying in neuron density, due to fundamental electrical properties of neurons. The maximum value of q primary may serve as an effective physiological constraint for MEG/EEG inverse solutions.

  3. Weak constraint four-dimensional variational data assimilation in a model of the California Current System

    Science.gov (United States)

    Crawford, William J.; Smith, Polly J.; Milliff, Ralph F.; Fiechter, Jerome; Wikle, Christopher K.; Edwards, Christopher A.; Moore, Andrew M.

    2016-12-01

    A new approach is explored for computing estimates of the error covariance associated with the intrinsic errors of a numerical forecast model in regions characterized by upwelling and downwelling. The approach used is based on a combination of strong constraint data assimilation, twin model experiments, linear inverse modeling, and Bayesian hierarchical modeling. The resulting model error covariance estimates Q are applied to a model of the California Current System using weak constraint four-dimensional variational (4D-Var) data assimilation to compute estimates of the ocean circulation. The results of this study show that the estimates of Q derived following our approach lead to demonstrable improvements in the model circulation estimates and isolate regions where model errors are likely to be important and that have been independently identified in the same model in previously published work.

  4. EAST equilibrium current profile reconstruction using polarimeter-interferometer internal measurement constraints

    Science.gov (United States)

    Qian, J. P.; Lao, L. L.; Liu, H. Q.; Ding, W. X.; Zeng, L.; Luo, Z. P.; Ren, Q. L.; Huang, Y.; Huang, J.; Brower, D. L.; Hanada, K.; Chen, D. L.; Sun, Y. W.; Shen, B.; Gong, X. Z.; Xiao, B. J.; Wan, B. N.

    2017-03-01

    The first equilibrium reconstruction of EAST current-density profile based on internal Faraday rotation measurements provided by the POlarimeter-INTerferometer (POINT) diagnostic is demonstrated using the EFIT equilibrium reconstruction code. EFIT incorporates 11 simultaneous line-integrated density and Faraday effect measurements from POINT to self-consistently reconstruct the equilibrium toroidal current density profile using a Faraday rotation reconstruction algorithm. It is shown that the POINT measurements can be applied to improve the accuracy of core plasma current density and q profile on EAST. Comparisons of magnetic surfaces and the q profile reconstructed using external magnetic data against those using magnetic and POINT data are presented. Equilibrium reconstructions using POINT data are found to be consistent with sawtooth phenomena. The sensitivity of equilibrium reconstruction to POINT measurements indicates Faraday rotation provides important constraints for determining the current profile.

  5. A distributed computing environment with support for constraint-based task scheduling and scientific experimentation

    Energy Technology Data Exchange (ETDEWEB)

    Ahrens, J.P.; Shapiro, L.G.; Tanimoto, S.L. [Univ. of Washington, Seattle, WA (United States). Dept. of Computer Science and Engineering

    1997-04-01

    This paper describes a computing environment which supports computer-based scientific research work. Key features include support for automatic distributed scheduling and execution and computer-based scientific experimentation. A new flexible and extensible scheduling technique that is responsive to a user`s scheduling constraints, such as the ordering of program results and the specification of task assignments and processor utilization levels, is presented. An easy-to-use constraint language for specifying scheduling constraints, based on the relational database query language SQL, is described along with a search-based algorithm for fulfilling these constraints. A set of performance studies show that the environment can schedule and execute program graphs on a network of workstations as the user requests. A method for automatically generating computer-based scientific experiments is described. Experiments provide a concise method of specifying a large collection of parameterized program executions. The environment achieved significant speedups when executing experiments; for a large collection of scientific experiments an average speedup of 3.4 on an average of 5.5 scheduled processors was obtained.

  6. Current status of the Standard Model CKM fit and constraints on $\\Delta F=2$ New Physics

    CERN Document Server

    Charles, J; Descotes-Genon, S; Lacker, H; Menzel, A; Monteil, S; Niess, V; Ocariz, J; Orloff, J; Perez, A; Qian, W; Tisserand, V; Trabelsi, K; Urquijo, P; Silva, L Vale

    2015-01-01

    This letter summarises the status of the global fit of the CKM parameters within the Standard Model performed by the CKMfitter group. Special attention is paid to the inputs for the CKM angles $\\alpha$ and $\\gamma$ and the status of $B_s\\to\\mu\\mu$ and $B_d\\to \\mu\\mu$ decays. We illustrate the current situation for other unitarity triangles. We also discuss the constraints on generic $\\Delta F=2$ New Physics. All results have been obtained with the CKMfitter analysis package, featuring the frequentist statistical approach and using Rfit to handle theoretical uncertainties.

  7. Flavour violation in gauge-mediated supersymmetry breaking models: Experimental constraints and phenomenology at the LHC

    Science.gov (United States)

    Fuks, Benjamin; Herrmann, Björn; Klasen, Michael

    2009-03-01

    We present an extensive analysis of gauge-mediated supersymmetry breaking models with minimal and non-minimal flavour violation. We first demonstrate that low-energy, precision electroweak, and cosmological constraints exclude large "collider-friendly" regions of the minimal parameter space. We then discuss various possibilities how flavour violation, although naturally suppressed, may still occur in gauge-mediation models. The introduction of non-minimal flavour violation at the electroweak scale is shown to relax the stringent experimental constraints, so that benchmark points, that are also cosmologically viable, can be defined and their phenomenology, i.e. squark and gaugino production cross sections with flavour violation, at the LHC can be studied.

  8. Flavour Violation in Gauge-Mediated Supersymmetry Breaking Models: Experimental Constraints and Phenomenology at the LHC

    CERN Document Server

    Fuks, B; Klasen, M

    2008-01-01

    We present an extensive analysis of gauge-mediated supersymmetry breaking models with minimal and non-minimal flavour violation. We first demonstrate that low-energy, precision electroweak, and cosmological constraints exclude large "collider-friendly" regions of the minimal parameter space. We then discuss various possibilities how flavour violation, although naturally suppressed, may still occur in gauge-mediation models. The introduction of non-minimal flavour violation at the electroweak scale is shown to relax the stringent experimental constraints, so that benchmark points, that are also cosmologically viable, can be defined and their phenomenology, i.e. squark and gaugino production cross sections with flavour violation, at the LHC can be studied.

  9. Flavour violation in gauge-mediated supersymmetry breaking models: Experimental constraints and phenomenology at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Fuks, Benjamin [Physikalisches Institut, Albert-Ludwigs-Universitaet Freiburg, Hermann-Herder-Strasse 3, D-79106 Freiburg im Breisgau (Germany); Herrmann, Bjoern [Laboratoire de Physique Subatomique et de Cosmologie, Universite Joseph Fourier/CNRS-IN2P3/INPG, 53 Avenue des Martyrs, F-38026 Grenoble (France); Klasen, Michael [Laboratoire de Physique Subatomique et de Cosmologie, Universite Joseph Fourier/CNRS-IN2P3/INPG, 53 Avenue des Martyrs, F-38026 Grenoble (France)], E-mail: klasen@lpsc.in2p3.fr

    2009-03-21

    We present an extensive analysis of gauge-mediated supersymmetry breaking models with minimal and non-minimal flavour violation. We first demonstrate that low-energy, precision electroweak, and cosmological constraints exclude large 'collider-friendly' regions of the minimal parameter space. We then discuss various possibilities how flavour violation, although naturally suppressed, may still occur in gauge-mediation models. The introduction of non-minimal flavour violation at the electroweak scale is shown to relax the stringent experimental constraints, so that benchmark points, that are also cosmologically viable, can be defined and their phenomenology, i.e. squark and gaugino production cross sections with flavour violation, at the LHC can be studied.

  10. First experimental results with the Current Limit Avoidance System at the JET tokamak

    Energy Technology Data Exchange (ETDEWEB)

    De Tommasi, G. [Associazione EURATOM-ENEA-CREATE, Università di Napoli Federico II, Via Claudio 21, 80125 Napoli (Italy); Galeani, S. [Dipartimento di Informatica, Sistemi e Produzione, Università di Roma, Tor Vergata, Rome (Italy); Jachmich, S. [Association EURATOM-Belgian State, Koninklijke Militaire School - Ecole Royale Militaire, B-1000 Brussels (Belgium); Joffrin, E. [IRFM-CEA, Centre de Cadarache, 13108 Saint-paul-lez-Durance (France); Lennholm, M. [EFDA Close Support Unit, Culham Science Centre, OX14 3DB Abingdon (United Kingdom); European Commission, B-1049 Brussels (Belgium); Lomas, P.J. [Euratom-CCFE, Culham Science Centre, OX14 3DB Abingdon (United Kingdom); Neto, A.C. [Associazione EURATOM-IST, Instituto de Plasmas e Fusao Nuclear, IST, 1049-001 Lisboa (Portugal); Maviglia, F. [Associazione EURATOM-ENEA-CREATE, Via Claudio 21, 80125 Napoli (Italy); McCullen, P. [Euratom-CCFE, Culham Science Centre, OX14 3DB Abingdon (United Kingdom); Pironti, A. [Associazione EURATOM-ENEA-CREATE, Università di Napoli Federico II, Via Claudio 21, 80125 Napoli (Italy); Rimini, F.G. [Euratom-CCFE, Culham Science Centre, OX14 3DB Abingdon (United Kingdom); Sips, A.C.C. [European Commission, B-1049 Brussels (Belgium); Varano, G.; Vitelli, R. [Dipartimento di Informatica, Sistemi e Produzione, Università di Roma, Tor Vergata, Rome (Italy); Zaccarian, L. [CNRS, LAAS, 7 Avenue du Colonel Roche, F-31400 Toulouse (France); Universitè de Toulouse, LAAS, F-31400 Toulouse (France)

    2013-06-15

    The Current Limit Avoidance System (CLA) has been recently deployed at the JET tokamak to avoid current saturations in the poloidal field (PF) coils when the eXtreme Shape Controller is used to control the plasma shape. In order to cope with the current saturation limits, the CLA exploits the redundancy of the PF coils system to automatically obtain almost the same plasma shape using a different combination of currents in the PF coils. In the presence of disturbances it tries to avoid the current saturations by relaxing the constraints on the plasma shape control. The CLA system has been successfully implemented on the JET tokamak and fully commissioned in 2011. This paper presents the first experimental results achieved in 2011–2012 during the restart and the ITER-like wall campaigns at JET.

  11. Experimental observation of direct current voltage-induced phase synchronization

    Indian Academy of Sciences (India)

    Haihong Li; Weiqing Liu; Qiongling Dai; Jinghua Xiao

    2006-09-01

    The dynamics of two uncoupled distinct Chua circuits driven by a common direct current voltage is explored experimentally. It was found that, with increasing current intensity, the dominant frequencies of these two Chua circuits will first vary at different speeds, approach an identical value for a certain current intensity and then separate. Techniques such as synchronization index and phase difference distribution were employed to analyze the phase coherence between these two Chua circuits.

  12. A Comparative Study of Dark Energy Constraints from Current Observational Data

    CERN Document Server

    Wang, Yun; Mukherjee, Pia

    2012-01-01

    We examine how dark energy constraints from current observational data depend on the analysis methods used: the analysis of Type Ia supernovae (SNe Ia), and that of galaxy clustering data. We generalize the flux-averaging analysis method of SNe Ia to allow correlated errors of SNe Ia, in order to reduce the systematic bias due to weak lensing of SNe Ia. We find that flux-averaging leads to larger errors on dark energy and cosmological parameters if only SN Ia data are used. When SN Ia data (the latest compilation by the SNLS team) are combined with WMAP 7 year results (in terms of our Gaussian fits to the probability distributions of the CMB shift parameters), the latest Hubble constant (H_0) measurement using the Hubble Space Telescope (HST), and gamma ray burst (GRB) data, flux-averaging of SNe Ia increases the concordance with other data, and leads to significantly tighter constraints on the dark energy density at z=1, and the cosmic curvature \\Omega_k. The galaxy clustering measurements of H(z=0.35)r_s(z_...

  13. Experimental constraints on the coupling of the Higgs boson to electrons

    CERN Document Server

    Altmannshofer, Wolfgang; Schmaltz, Martin

    2015-01-01

    In the standard model (SM), the coupling of the Higgs boson to electrons is real and very small, proportional to the electron mass. New physics could significantly modify both real and imaginary parts of this coupling. We discuss experiments which are sensitive to the Higgs-electron coupling and derive the current bounds on new physics contributing to this coupling. The strongest constraint follows from the ACME bound on the electron electric dipole moment (EDM). We calculate the full analytic two-loop result for the electron EDM and show that it bounds the imaginary part of the Higgs-electron coupling to be less than 1.7 x 10^-2 times the SM electron Yukawa coupling. Deviations of the real part are much less constrained. We discuss bounds from Higgs decays, resonant Higgs production at electron colliders, Higgs mediated B -> e^+ e^- decays, and the anomalous magnetic moment of the electron. Currently, the strongest constraint comes from h -> e^+ e^- at the LHC, bounding the coupling to be less than ~600 time...

  14. Ecophysiological response of Adelie penguins facing an experimental increase in breeding constraints.

    Science.gov (United States)

    Beaulieu, M; Spée, M; Lazin, D; Ropert-Coudert, Y; le Maho, Y; Ancel, A; Raclot, T

    2010-01-01

    Foraging strategies play a key role in breeding effort. Little is known, however, about their connection with hormonal and nutritional states, especially when breeding constraints vary. Here, we experimentally increased foraging costs and thus breeding constraints by handicapping Adélie penguins (Pygoscelis adeliae) with dummy devices representing 3-4% of the penguins' cross-sectional area. We examined food-related stress (via plasma corticosterone concentration) and nutritional state (via metabolite levels). Concurrently, we investigated the use of ecological niches via the isotopic signature of red blood cells indicating the trophic position (delta(15)N) and the spatial distribution (delta(13)C) of penguins. Handicapped birds performed approximately 70% longer foraging trips and lost approximately 60% more body mass than controls and their partners. However, corticosterone levels and the nutritional state were unchanged. The isotopic signature revealed that males and females differed in their foraging behaviour: upper trophic levels contributed more in the males' diet, who foraged in more pelagic areas. Handicapped and partner birds adopted the same strategy at sea: a shift towards higher delta(13)C values suggested that they foraged in more coastal areas than controls. This change in foraging decisions may optimize feeding time by decreasing travelling time. This may partly compensate for the presumed lower foraging efficiency of handicapped birds and for the energetic debt of their partners who had to fast approximately 70% longer on the nest. We propose that this flexible use of ecological niches may allow birds facing increased breeding constraints to avoid chronic stress and to minimize the impact on their body condition.

  15. Experimental Setup for the Investigation of Superconducting Persistent Current

    Science.gov (United States)

    2015-09-01

    NOTES 14. ABSTRACT We report on a recent experimental setup for the investigation of the relaxation rate of the persistent current in an assembly of...at cryo-temperatures in magnetic field at time scale of seconds to hours. 15. SUBJECT TERMS persistent current, 2G HTS, coated conductor, relaxation ... activation . One unknown aspect is the variation of the coils’ position with temperature from room to cryogenic. A better design of the coils assembly

  16. The strongest experimental constraints on SU(5)xU(1) supergravity models

    CERN Document Server

    López, J; Park, G; Zichichi, A

    1994-01-01

    We consider a class of well motivated string-inspired flipped $SU(5)$ supergravity models which include four supersymmetry breaking scenarios: no-scale, strict no-scale, dilaton, and special dilaton, such that only three parameters are needed to describe all new phenomena $(m_t,\\tan\\beta,m_{\\tilde g})$. We show that the LEP precise measurements of the electroweak parameters in the form of the $\\epsilon_1$ variable, and the CLEOII allowed range for $\\bsg$ are at present the most important experimental constraints on this class of models. For $m_t\\gsim155\\,(165)\\GeV$, the $\\epsilon_1$ constraint (at 90(95)\\%CL) requires the presence of light charginos ($m_{\\chi^\\pm_1}\\lsim50-100\\GeV$ depending on $m_t$). Since all sparticle masses are proportional to $m_{\\tilde g}$, $m_{\\chi^\\pm_1}\\lsim100\\GeV$ implies: $m_{\\chi^0_1}\\lsim55\\GeV$, $m_{\\chi^0_2}\\lsim100\\GeV$, $m_{\\tilde g}\\lsim360\\GeV$, $m_{\\tilde q}\\lsim350\\,(365)\\GeV$, $m_{\\tilde e_R}\\lsim80\\,(125)\\GeV$, $m_{\\tilde e_L}\\lsim120\\,(155)\\GeV$, and $m_{\\tilde\

  17. Experimental constraints on anti-gravity and antimatter, in the context of dark energy

    CERN Document Server

    Ting, Yuan-Sen

    2013-01-01

    In a paper by Villata (2011), the possibility of a repulsive gravitational interaction between antimatter and ordinary matter was discussed. The author argued that this anti-gravity can be regarded as a prediction of general relativity, under the assumption of CPT symmetry. Stringent experimental constraints have been established against such a suggestion. The measurement of free-fall accelerations of various nuclei by the Eot-Wash group and searches for equivalence principle violation through the gravitational splitting in kaon physics consistently establish null results on any difference between the gravitational behaviour of antimatter and ordinary matter. The original arguments against antigravity were questioned by Nieto & Goldman (1991). In the light of new experiments as well as theoretical developments in the past 20 years, some of Nieto & Goldman's concerns have been addressed. While a precise measurement of the free-fall acceleration of antihydrogen will eventually lay this issue to rest, th...

  18. Predictions for Supersymmetric Particle Masses using Indirect Experimental and Cosmological Constraints

    CERN Document Server

    Buchmüller, O L; de Roeck, A; Ellis, Jonathan Richard; Flächer, H; Heinemeyer, S; Isidori, G; Olive, K A; Paradisi, P; Ronga, F J; Weiglein, G

    2008-01-01

    In view of the imminent start of the LHC experimental programme, we use the available indirect experimental and cosmological information to estimate the likely range of parameters of the constrained minimal supersymmetric extension of the Standard Model (CMSSM), using a Markov-chain Monte Carlo (MCMC) technique to sample the parameter space. The 95% confidence-level area in the (m_0, m_1/2) plane of the CMSSM lies largely within the region that could be explored with 1/fb of integrated luminosity at 14 TeV, and much of the 68% confidence-level area lies within the region that could be explored with 50/pb of integrated luminosity at 10 TeV. A same-sign dilepton signal could well be visible in most of the 68% confidence-level area with 1/fb of integrated luminosity at 14 TeV. We discuss the sensitivities of the preferred ranges to variations in the most relevant indirect experimental and cosmological constraints and also to deviations from the universality of the supersymmetry-breaking contributions to the mass...

  19. Biparental incubation-scheduling: no experimental evidence for major energetic constraints.

    Science.gov (United States)

    Bulla, Martin; Cresswell, Will; Rutten, Anne L; Valcu, Mihai; Kempenaers, Bart

    2015-01-01

    Incubation is energetically demanding, but it is debated whether these demands constrain incubation-scheduling (i.e., the length, constancy, and timing of incubation bouts) in cases where both parents incubate. Using 2 methods, we experimentally reduced the energetic demands of incubation in the semipalmated sandpiper, a biparental shorebird breeding in the harsh conditions of the high Arctic. First, we decreased the demands of incubation for 1 parent only by exchanging 1 of the 4 eggs for an artificial egg that heated up when the focal bird incubated. Second, we reanalyzed the data from the only published experimental study that has explicitly tested energetic constraints on incubation-scheduling in a biparentally incubating species (Cresswell et al. 2003). In this experiment, the energetic demands of incubation were decreased for both parents by insulating the nest cup. We expected that the treated birds, in both experiments, would change the length of their incubation bouts, if biparental incubation-scheduling is energetically constrained. However, we found no evidence that heating or insulation of the nest affected the length of incubation bouts: the combined effect of both experiments was an increase in bout length of 3.6min (95% CI: -33 to 40), which is equivalent to a 0.5% increase in the length of the average incubation bout. These results demonstrate that the observed biparental incubation-scheduling in semipalmated sandpipers is not primarily driven by energetic constraints and therefore by the state of the incubating bird, implying that we still do not understand the factors driving biparental incubation-scheduling.

  20. Experimental typography : reviewing the modernist and the current approaches

    OpenAIRE

    Makal, Eray

    1993-01-01

    Ankara : The Department of Graphic Design and Institute of Fine Arts, Bilkent Univ., 1993. Thesis (Master's) -- Bilkent University, 1993. Includes bibliographical references leaves 65-66. The intention of this study is to evaluate the experimental typography within the history of graphic design by taking in consideration of two epochs. The Modernist and The Current. Makal, Eray M.S.

  1. Halo current diagnostic system of experimental advanced superconducting tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Chen, D. L.; Shen, B.; Sun, Y.; Qian, J. P., E-mail: jpqian@ipp.ac.cn; Wang, Y.; Xiao, B. J. [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031 (China); Granetz, R. S. [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States)

    2015-10-15

    The design, calibration, and installation of disruption halo current sensors for the Experimental Advanced Superconducting Tokamak are described in this article. All the sensors are Rogowski coils that surround conducting structures, and all the signals are analog integrated. Coils with two different cross-section sizes have been fabricated, and their mutual inductances are calibrated. Sensors have been installed to measure halo currents in several different parts of both the upper divertor (tungsten) and lower divertor (graphite) at several toroidal locations. Initial measurements from disruptions show that the halo current diagnostics are working well.

  2. Halo current diagnostic system of experimental advanced superconducting tokamak

    Science.gov (United States)

    Chen, D. L.; Shen, B.; Granetz, R. S.; Sun, Y.; Qian, J. P.; Wang, Y.; Xiao, B. J.

    2015-10-01

    The design, calibration, and installation of disruption halo current sensors for the Experimental Advanced Superconducting Tokamak are described in this article. All the sensors are Rogowski coils that surround conducting structures, and all the signals are analog integrated. Coils with two different cross-section sizes have been fabricated, and their mutual inductances are calibrated. Sensors have been installed to measure halo currents in several different parts of both the upper divertor (tungsten) and lower divertor (graphite) at several toroidal locations. Initial measurements from disruptions show that the halo current diagnostics are working well.

  3. Experimental melts from crustal rocks: A lithochemical constraint on granite petrogenesis

    Science.gov (United States)

    Gao, Peng; Zheng, Yong-Fei; Zhao, Zi-Fu

    2016-12-01

    Many studies of experimental petrology have devoted to partial melting of crustal rocks. In order to provide lithochemical constraints on granite petrogenesis, this paper presents a compilation and synthesis of available experimental data for the major element compositions of felsic melts derived from partial melting of natural or synthetic materials in the compositional range of crustal rocks. The experimental melts are categorized into four types according to the species of hydrous minerals in starting materials: (I) amphibole-bearing; (II) amphibole- and biotite-bearing; (III) biotite-bearing; and (IV) biotite- and muscovite-bearing. If dehydration melting takes place at normal crustal conditions (P = 5-10 kbar, T ≤ 1000 °C), experimental melts are rich in SiO2 but poor in MgO + FeOT except those from amphibole-bearing sources. A comprehensive comparison of compositions between experimental melts and starting materials indicates that geochemical fractionation is variable for different major elements and their ratios. Source composition and melting temperature exert stronger controls on the compositional variations of experimental melts than pressure and fluid. By comparing the experimental melts with natural granites, the following insights into granite petrogenesis can be got: (1) while peritectic assemblage entrainment may be the dominant mechanism for the compositional variations of garnet/cordierite-rich S-type granites, fractional crystallization of diverse melts from heterogeneous metasedimentary precursors probably governs the compositional variations of garnet/cordierite-poor S-type granites; (2) relatively K2O-rich mafic to intermediate rocks are appropriate sources for calc-alkaline I-type granites. The compositional variations of calc-alkaline granites are jointly controlled by peritectic assemblage entrainment and subsequent fractional crystallization; (3) while dehydration melting at T > 950 °C is appropriate for the production of ferroan and

  4. Experimental Gravity Currents Propagating Downslope Over A Synthetic Topography

    Science.gov (United States)

    Burgos Cuevas, Andrea; Ruiz-Angulo, Angel; Palacios-Morales, Carlos

    2016-11-01

    Lock-release gravity currents are studied experimentally in order to investigate their dynamics and the mixing process between them and the ambient fluid. We produced these currents in a laboratory tank and allow them to propagate downslope first in a flat slope and then in a rough one with a synthetic topography. This topography is similar to the one of a side of a mountain near mexico's valley. Our aim is to investigate the dynamics of gravity currents as similar as possible to the mountain breezes that can develop around this valley. To the best of our knowledge, there are few experimental investigations that take into account the roughness of the slope. For each experiment, we obtain the instantaneous velocity fields using the standard piv technique. From the velocity fields, we estimate the entrainment coefficient time series. We found that this coefficient depends on the roughness of the surface where the current propagates. Besides, pressure time series were obtained in synthetic stations along the rough profile. These series showed a very clear signal of the gravity current propagating along the slope.

  5. Transcranial Direct Current Stimulation Potentiates Improvements in Functional Ability in Patients With Chronic Stroke Receiving Constraint-Induced Movement Therapy

    DEFF Research Database (Denmark)

    Figlewski, Krystian; Blicher, Jakob Udby; Mortensen, Jesper;

    2017-01-01

    BACKGROUND AND PURPOSE: Transcranial direct current stimulation may enhance effect of rehabilitation in patients with chronic stroke. The objective was to evaluate the efficacy of anodal transcranial direct current stimulation combined with constraint-induced movement therapy of the paretic upper...... limb. METHODS: A total of 44 patients with stroke were randomly allocated to receive 2 weeks of constraint-induced movement therapy with either anodal or sham transcranial direct current stimulation. The primary outcome measure, Wolf Motor Function Test, was assessed at baseline and after...... the intervention by blinded investigators. RESULTS: Both groups improved significantly on all Wolf Motor Function Test scores. Group comparison showed improvement on Wolf Motor Function Test in the anodal group compared with the sham group. CONCLUSIONS: Anodal transcranial direct current stimulation combined...

  6. Experimental simulation of gravity currents in erodible bed

    Science.gov (United States)

    Bateman, A.; La Roca, M.; Medina, V.

    2009-04-01

    Gravity currents are commonly met in nature, when a flow of denser fluid moves into a less dense one. A typical example of a gravity current is given by the sea water which flows into the bottom of a river during the summer, in correspondence of the estuary, when the river's discharge attains low values. In this case, dangerous consequences can occur, because of the polluting of the aquifer caused by the salty water. Density currents also occurs in lakes and reservoirs, because of a change in temperature or because a flood, both can produce some environmental impacts that are of interest to the local water Agency of the different countries. Of particular relevance is also the interaction of the gravity current with the movement of the sediments from the bottom of the bed. The international state of the art is particularly concerned with experimental and numerical investigation on gravity currents on fixed and porous bed [1-2-3], while, to the authors' knowledge, the interaction of a gravity current with an erodible bed is still an open field of investigation. In this paper experiments concerning with the propagation of a gravity current over fixed and erodible bed are presented. The experiments, conducted at the laboratory of Hydraulics of the Universitat Politecnica de Catalunya (actually in the Prof. Bateman's blue room), were concerned with a transparent tank 2 m long, 0.2 m wide and 0.3 m deep, partly filled with salty water and partly with fresh water, up to a depth of 0.28 m. The salty water, whose density was in the range 1050John E. Simpson. Gravity Currents [3] J.J. Monaghan, R.A.F. Cas, A.M. Kos, M. Hallworth, Gravity currents descending a ramp in a stratified tank, The Journal of Fluid Mechanics, Vol. 379, 1999

  7. Constraint Differentiation

    DEFF Research Database (Denmark)

    Mödersheim, Sebastian Alexander; Basin, David; Viganò, Luca

    2010-01-01

    , under the assumption that the original constraint-based approach has these properties. Practically, as a concrete case study, we have integrated this technique into OFMC, a state-of-the-art model-checker for security protocol analysis, and demonstrated its effectiveness by extensive experimentation. Our......We introduce constraint differentiation, a powerful technique for reducing search when model-checking security protocols using constraint-based methods. Constraint differentiation works by eliminating certain kinds of redundancies that arise in the search space when using constraints to represent...

  8. An Experimental Study on Constraint Cooling Process of Hot-rolled CoilS

    Institute of Scientific and Technical Information of China (English)

    Lijuan WANG; Chunli ZHANG

    2003-01-01

    In order to master mechanical property, surface quality and microstructure of constraint cooling (CC) coils undervarious water cooling parameters, more than 100 coils cooling experiments were done with real production process,of which is designed a coolin

  9. Experimental constraints on mineral-melt reactions in the Middle Zone of the Skaergaard intrusion

    Science.gov (United States)

    Veksler, I. V.; Nielsen, T. F.

    2009-12-01

    The Eocene Skaergaard intrusion (East Greenland) is the classical example of the Fe enrichment trend in tholeitic magma. Despite numerous attempts to reproduce the trend experimentally, its direction in the Middle Zone (MZ) of the intrusion remains contentious. It remains unclear whether the strong Fe enrichment of the magma continued after the start of ilmenite and magnetite crystallization. Thy et al. (2009) recently showed that the modal ratio of Fe-Ti oxide minerals to Fe-Mg silicates in average Skaergaard rocks was lower than the experimentally determined cotectic proportions. In our view, the difference probably resulted from mineral-melt post-cumulus reactions. Cumulus assemblage in the MZ comprised plagioclase, high- and low-Ca pyroxenes, ilmenite and magnetite. Olivine is locally present as an inter-cumulus phase. All the minerals and the liquid were involved in continuous and discontinuous reaction series. Traces of the reactions are ubiquitous throughout the intrusion, and especially prominent around autolithic blocks (Irvine et al., 1998; McBirney, 2009). We examined experimental constraints on the reactions from 67 experimental equilibria compiled from 25 publications, in which dry silicate melts coexisted with plagioclase, olivine, and two pyroxenes. The experiments had been carried out at 1 atm, temperatures between 1040 and 1180 °C, and variable fO2. We found that the 4-mineral assemblage did not constrain a narrow range of liquid compositions. For example, SiO2 in the liquids varies broadly from 42 to 66 wt.%. Cotectic proportions of the crystal phases vary accordingly. FeO and alkalis impose strong and opposite effects on the cotectic proportions and equilibrium melt compositions. Thus, alkali-poor liquids evolve to FeO concentrations of up to 30 wt. %. We propose that the mineral-melt reactions compounded by migration of FeO and alkalis in the liquid may explain poorly understood phenomena such as the reverse evolution of plagioclase towards

  10. Current and future constraints on Bekenstein-type models for varying couplings

    CERN Document Server

    Leite, A C O

    2016-01-01

    Astrophysical tests of the stability of dimensionless fundamental couplings, such as the fine-structure constant $\\alpha$ and the proton-to-electron mass ratio $\\mu$, are an optimal probe of new physics. There is a growing interest in these tests, following indications of possible spacetime variations at the few parts per million level. Here we make use of the latest astrophysical measurements, combined with background cosmological observations, to obtain improved constraints on Bekenstein-type models for the evolution of both couplings. These are arguably the simplest models allowing for $\\alpha$ and $\\mu$ variations, and are characterized by a single free dimensionless parameter, $\\zeta$, describing the coupling of the underlying dynamical degree of freedom to the electromagnetic sector. In the former case we find that this parameter is constrained to be $|\\zeta_\\alpha|<4.8\\times10^{-6}$ (improving previous constraints by a factor of 6), while in the latter (which we quantitatively compare to astrophysic...

  11. Experimental Investigation of Turbulence Specifications of Turbidity Currents

    Directory of Open Access Journals (Sweden)

    B Firoozabadi

    2010-01-01

    Full Text Available The present study investigates the turbulence characteristic of turbidity current experimentally. The three-dimensional Acoustic-Doppler Velocimeter (ADV was used to measure the instantaneous velocity and characteristics of the turbulent flow. The experiments were conducted in a three-dimensional channel for different discharge flows, concentrations, and bed slopes. Results are expressed at various distances from the inlet, for all flow rates, slopes and concentrations as the distribution of turbulence energy, Reynolds stress and the turbulent intensity. It was concluded that the maximum turbulence intensity happens in both the interface and near the wall. Also, it was observed that the turbulence intensity reaches its minimum where maximum velocity occurs.

  12. Recent experimental results of KSTAR RF heating and current drive

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S. J., E-mail: sjwang@nfri.re.kr; Kim, J.; Jeong, J. H.; Kim, H. J.; Joung, M.; Bae, Y. S.; Kwak, J. G. [National Fusion Research Institute, Daejoen, 305-806 (Korea, Republic of)

    2015-12-10

    The overview of KSTAR activities on ICRH, LHCD and ECH/CD including the last experimental results and future plan aiming for long-pulse high-beta plasma will be presented. Recently we achieved reasonable coupling of ICRF power to H-mode plasma through several efforts to increase system reliability. Power balance will be discussed on this experiment. LHCD is still struggling in the low power regime. Review of antenna spectrum for the higher coupling in H-mode plasma will be tried. ECH/CD provides 41 sec, 0.8 MW of heating power to support high-performance long-pulse discharge. Also, 170 GHz ECH system is integrated with the Plasma Control System (PCS) for the feedback controlling of NTM. Status and plan of ECH/CD will be discussed. Finally, helicon current drive is being prepared for the next stage of KSTAR operation. The hardware preparation and the calculation results of helicon current drive in KSTAR plasma will be discussed.

  13. Model-independent constraints on modified gravity from current data and from the Euclid and SKA future surveys

    CERN Document Server

    Taddei, Laura; Amendola, Luca

    2016-01-01

    The aim of this paper is to constrain modified gravity with redshift space distortion observations and supernovae measurements. Compared with a standard LCDM analysis, we include three additional free parameters, namely the initial conditions of the matter perturbations,the overall perturbation normalization, and a scale-dependent Y parameter modifying the Poisson equation, in an attempt to perform a more model-independent analysis. First, we constrain the Poisson parameter Y (also called Geff ) by using currently available fsigma_8 data and the recent SN catalog JLA. We find that the inclusion of the additional free parameters makes the constraints significantly weaker than when fixing them to the standard cosmological value. Second, we constrain Y by using forecast growth-rate data for Euclid and SKA missions. Here again we point out the weakening of the constraints when the additional parameters are included. Finally, we adopt as modified gravity Poisson parameter the specific Horndeski form, and use scale...

  14. Experimental and modeling constraints on the seismic structure of oceanic lithosphere

    Science.gov (United States)

    Faul, Ulrich; Jackson, Ian; Hall, Paul

    2014-05-01

    Seismological techniques provide different views of the structure of the oceanic upper mantle. Surface waves can not resolve sharp changes in velocities with depth, but provide absolute velocities. Receiver functions are sensitive to sharp changes, but these steps in velocities have to be reconciled with absolute velocities. Experimental measurements of seismic properties can be used to translate velocities into a physical state and to explore possible mechanisms for sharp changes. Current experiments at elevated pressures and temperatures are designed to resolve the onset of the deviation from elastic behavior at temperatures above 600ºC. Initial experiments with copper jackets, which avoid the interference from phase transitions in mild steel, confirm the existence of a plateau in dissipation in olivine that is due to the grain-scale process of elastically accommodated grain boundary sliding. As this mechanism is solely due to temperature it occurs everywhere in the thermal boundary layer, although the sharpness will depend on the temperature gradient. Forward modeling of seismic velocities with the experimentally determined properties predict velocity gradients in the thermal boundary layer that are not sharp enough to generate receiver functions. However, particularly for younger oceanic lithosphere these gradients only need to be enhanced by a relatively small amount by other factors. Possible mechanisms include the presence of melt and/or volatiles. For older oceanic lithosphere small scale convection may steepen the temperature gradient beneath the lid. We are currently conducting numerical models with experimentally derived rheological parameters with the aim to determine the thermal structure and calculate seismic velocities from it. If operative, small scale convection may also lead to cooling of the whole upper mantle as a function of age. In the upper part of the lithosphere seismologic observations imply a constant, high velocity lid. This contrasts

  15. Constraints on new physics in the electroweak bosonic sector from current data and future experiments

    CERN Document Server

    Hagiwara, K; Szalapski, R

    1995-01-01

    Extensions of the Standard Model which involve a new scale, \\Lambda, may, for energies sufficiently small compared to this new scale, be expressed in terms of operators with energy dimension greater than four. The coefficients of just four SU(2)\\timesU(1)-gauge-inva riant energy-dimension-six operators are sufficient to parameterize the contributions of new physics in the electroweak bosonic sector to electroweak precision measurements. In this letter we update constraints on the coefficients of these four operators due to recent precision measurements of electroweak observables. We further demonstrate how such constraints may be improved by experiments at TRISTAN, LEP2 and at a future linear e^+e^- collider. The relationship of these operators to the oblique parameters S, T and U is examined. Two of the operators contribute to a non-standard running of the electroweak charge form-factors \\overline{\\alpha}(q^2), \\overline{s}^2(q^2), \\overline{g}_Z^2(q^2) and \\overline{g}_W^2(q^2); in the special case where th...

  16. Constraint-Induced Movement Therapy (CIMT: Current Perspectives and Future Directions

    Directory of Open Access Journals (Sweden)

    Aimee P. Reiss

    2012-01-01

    Full Text Available Constraint-induced movement therapy (CIMT has gained considerable popularity as a treatment technique for upper extremity rehabilitation among patients with mild-to-moderate stroke. While substantial evidence has emerged to support its applicability, issues remain unanswered regarding the best and most practical approach. Following the establishment of what can be called the “signature” CIMT approach characterized by intense clinic/laboratory-based practice, several distributed forms of training, collectively known as modified constraint therapy (mCIMT, have emerged. There is a need to examine the strengths and limitations of such approaches, and based upon such information, develop the components of a study that would compare the signature approach to the best elements of mCIMT, referred to here as “alternative” CIMT. Based upon a PEDro review of literature, limitations in mCIMT studies for meeting criteria were identified and discussed. A suggestion for a “first effort” at a comparative study that would both address such limitations while taking practical considerations into account is provided.

  17. ITER (International Thermonuclear Experimental Reactor) current drive and heating physics

    Energy Technology Data Exchange (ETDEWEB)

    Nevins, W.M.; Lindquist, W. (Lawrence Livermore National Lab., CA (USA)); Fujisawa, N.; Kimura, H. (Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan)); Hopman, H.; Rebuffi, L.; Wegrowe, J.G. (Max-Planck-Institut fuer Plasmaphysik, Garching (Germany, F.R.). NET Design Team); Parail, V.; Vdovin, V. (Gosudarstvennyj Komitet po Ispol' zovaniyu Atomnoj Ehnergii SSSR, Moscow (USSR). Inst. Atomnoj Ehn

    1990-01-01

    The ITER Current Drive and Heating (CD H) systems are required for: Ionization and current initiation; Non-inductive current ramp-up assist; Heating of the plasma; Steady-state operation with full non-inductive current drive; Current profile control; and Burn control by modulation of the auxiliary power. Steady-state current drive is the most demanding requirement, so this has driven the choice of the ITER current drive and heating systems.

  18. Binary Encodings of Non-binary Constraint Satisfaction Problems: Algorithms and Experimental Results

    CERN Document Server

    Samaras, N; 10.1613/jair.1776

    2011-01-01

    A non-binary Constraint Satisfaction Problem (CSP) can be solved directly using extended versions of binary techniques. Alternatively, the non-binary problem can be translated into an equivalent binary one. In this case, it is generally accepted that the translated problem can be solved by applying well-established techniques for binary CSPs. In this paper we evaluate the applicability of the latter approach. We demonstrate that the use of standard techniques for binary CSPs in the encodings of non-binary problems is problematic and results in models that are very rarely competitive with the non-binary representation. To overcome this, we propose specialized arc consistency and search algorithms for binary encodings, and we evaluate them theoretically and empirically. We consider three binary representations; the hidden variable encoding, the dual encoding, and the double encoding. Theoretical and empirical results show that, for certain classes of non-binary constraints, binary encodings are a competitive op...

  19. Constraints on the Dynamics of Seabed Pockmarks: an Integrated Sedimentological, Biostratigraphic, Geophysical, Oceanographic and Experimental Approach

    Science.gov (United States)

    Pau, M.; Hammer, Ø.; Chand, S.; Gisler, G. R.

    2015-12-01

    Pockmarks are crater-like seabed depressions commonly resulting from focused fluid escape from soft, fine-grained sediments. Typically measuring 20-50 m across with depths of 2-10 m, these features often occur in extensive fields containing hundreds of them per square kilometre. They are prominent hazards for offshore installations such as oil rigs and pipelines, affecting vast areas worldwide. Besides, they represent a major geological source of methane, and their importance has been pointed out as contributors to the global climate variability.Sedimentological and biostratigraphic analyses of sediment cores were coupled with shallow seismic images to investigate the origin and evolution of a pockmark field in the southwestern Barents Sea, an epicontinental sea part of the Arctic Ocean. The pockmarks formed as a result of reduced sedimentation above active gas seeps near the retreating edge of the Barents Sea ice sheet about 15,000 years ago. The seepage is ascribed to climate change-induced dissociation of methane hydrates. These findings strengthen the case that pockmarks, worldwide, recorded the release of massive quantities of methane from the seafloor into the ocean during the last deglaciation. No evidence was found for current upward methane flux, so the pockmarks in the study area appear as inactive seabed features. Field measurements of currents and sediment fluxes in pockmarks in the Oslofjord, Norway, along with an experimental hydrodynamics study, provide insight into the mechanisms responsible for the long-term maintenance of inactive pockmarks. Near-bed currents may control the net sedimentation rate in these depressions by inhibiting the sedimentation from suspended transport. Enhanced turbulence and more intense biological activity suggest that the suspended fines are supported in the water column more easily in the pockmarks than on the surrounding bed, and can be transported away before settling. Moreover, upwelling generated by flow deflection

  20. Translational constraint influences dynamic spinal canal occlusion of the thoracic spine: an in vitro experimental study.

    Science.gov (United States)

    Zhu, Qingan; Lane, Chris; Ching, Randal P; Gordon, Jeff D; Fisher, Charles G; Dvorak, Marcel F; Cripton, Peter A; Oxland, Thomas R

    2008-01-01

    Mechanical constraints to spine motion can arise in a variety of real-world situations such as when shoulder belts prevent anterior translation of the thorax during automotive collisions. The effect of such constraint on spinal column-spinal cord interaction during injury remains unknown. The purpose of the present study was to compare maximal dynamic spinal canal occlusion, measured via a specialized transducer, in cadaveric upper thoracic spine specimens under a variety of anterior-posterior constraint conditions. Four injury models were produced using 24 cadaveric spine specimens (T1-T4). Incremental compressive trauma was applied under constrained (i.e. blocked anterior-posterior translation) flexion-compression, pure-compression and extension-compression, and under unconstrained (i.e. free anterior-posterior translation) flexion-compression. All displacements were applied at 500 mm/s. For all three constrained trauma groups, complete transducer occlusion occurred between 20 and 30 mm of compressive displacement. The extension-compression caused transducer occlusion significantly less than the other constrained models (p design of injury prevention devices.

  1. Current Dark Matter Annihilation Constraints from CMB and Low-Redshift Data

    CERN Document Server

    Madhavacheril, Mathew S; Slatyer, Tracy R

    2013-01-01

    Updated constraints on dark matter cross section and mass are presented combining CMB power spectrum measurements from Planck, WMAP9, ACT, and SPT as well as several low-redshift datasets (BAO, HST, supernovae). For the CMB datasets, we combine WMAP9 temperature and polarization data for l 2500, and Planck CMB four-point lensing measurements. We allow for redshift-dependent energy deposition from dark matter annihilation by using a `universal' energy absorption curve. We also include an updated treatment of the excitation, heating, and ionization energy fractions, and provide updated deposition efficiency factors (f_eff) for 41 different dark matter models. Assuming perfect energy deposition (f_eff = 1) and a thermal cross section, dark matter masses below 26 GeV are excluded at the 2-sigma level. Assuming a more generic efficiency of f_eff = 0.2, thermal dark matter masses below 5 GeV are disfavored at the 2-sigma level. These limits are a factor of ~2 improvement over those from WMAP9 data alone. These cur...

  2. New constraints on kinetic isotope effects during CO2(aq) hydration and hydroxylation: Revisiting theoretical and experimental data

    Science.gov (United States)

    Sade, Ziv; Halevy, Itay

    2017-10-01

    CO2 (de)hydration (i.e., CO2 hydration/HCO3- dehydration) and (de)hydroxylation (i.e., CO2 hydroxylation/HCO3- dehydroxylation) are key reactions in the dissolved inorganic carbon (DIC) system. Kinetic isotope effects (KIEs) during these reactions are likely to be expressed in the DIC and recorded in carbonate minerals formed during CO2 degassing or dissolution of gaseous CO2. Thus, a better understanding of KIEs during CO2 (de)hydration and (de)hydroxylation would improve interpretations of disequilibrium compositions in carbonate minerals. To date, the literature lacks direct experimental constraints on most of the oxygen KIEs associated with these reactions. In addition, theoretical estimates describe oxygen KIEs during separate individual reactions. The KIEs of the related reverse reactions were neither derived directly nor calculated from a link to the equilibrium fractionation. Consequently, KIE estimates of experimental and theoretical studies have been difficult to compare. Here we revisit experimental and theoretical data to provide new constraints on oxygen KIEs during CO2 (de)hydration and (de)hydroxylation. For this purpose, we provide a clearer definition of the KIEs and relate them both to isotopic rate constants and equilibrium fractionations. Such relations are well founded in studies of single isotope source/sink reactions, but they have not been established for reactions that involve dual isotopic sources/sinks, such as CO2 (de)hydration and (de)hydroxylation. We apply the new quantitative constraints on the KIEs to investigate fractionations during simultaneous CaCO3 precipitation and HCO3- dehydration far from equilibrium.

  3. Experimental study of blockage of monochromatic waves by counter currents

    NARCIS (Netherlands)

    Suastika, I.K.

    1999-01-01

    Blockage of waves by a current can occur if waves are propagating on a spatially varying opposing current in which the velocity is increasing in the wave propagation direction. The ongoing waves become shorter and steeper while they are propagating against the current. Blocking occurs at the

  4. Experimental Study on Current-Driven Domain Wall Motion

    Science.gov (United States)

    Ono, T.; Yamaguchi, A.; Tanigawa, H.; Yano, K.; Kasai, S.

    2006-06-01

    Current-driven domain wall (DW) motion for a well-defined single DW in a micro-fabricated magnetic wire with submicron width was investigated by real-space observation with magnetic force microscopy. Magnetic force microscopy visualizes that a single DW introduced in a wire is displaced back and forth by positive and negative pulsed-current, respectively. Effect of the Joule heating, reduction of the threshold current density by shape control, and magnetic ratchet effect are also presented.

  5. Experimental study of the dynamics of a thin current sheet

    Science.gov (United States)

    Gekelman, W.; DeHaas, T.; Van Compernolle, B.; Daughton, W.; Pribyl, P.; Vincena, S.; Hong, D.

    2016-05-01

    Many plasmas in natural settings or in laboratory experiments carry currents. In magnetized plasmas the currents can be narrow field-aligned filaments as small as the electron inertial length ≤ft(\\tfrac{c}{{ω }pe}\\right) in the transverse dimension or fill the entire plasma column. Currents can take the form of sheets, again with the transverse dimension the narrow one. Are laminar sheets of electric current in a magnetized plasma stable? This became an important issue in the 1960s when current-carrying plasmas became key in the quest for thermonuclear fusion. The subject is still under study today. The conditions necessary for the onset for tearing are known, the key issue is that of the final state. Is there a final state? One possibility is a collection of stable tubes of current. On the other hand, is the interaction between the current filaments which are the byproduct endless, or does it go on to become chaotic? The subject of three-dimensional current systems is intriguing, rich in a variety of phenomena on multiple scale sizes and frequencies, and relevant to fusion studies, solar physics, space plasmas and astrophysical phenomena. In this study a long (δz = 11 m) and narrow (δx = 1 cm, δy = 20 cm) current sheet is generated in a background magnetoplasma capable of supporting Alfvén waves. The current is observed to rapidly tear into a series of magnetic islands when viewed in a cross-sectional plane, but they are in essence three-dimensional flux ropes. At the onset of the current, magnetic field line reconnection is observed between the flux ropes. The sheet on the whole is kink-unstable, and after kinking exhibits large-scale, low-frequency (f ≪ f ci ) rotation about the background field with an amplitude that grows with distance from the source of the current. Three-dimensional data of the magnetic and electric fields is acquired throughout the duration of the experiment and the parallel resistivity is derived from it. The parallel

  6. As it happens: current directions in experimental evolution.

    Science.gov (United States)

    Bataillon, Thomas; Joyce, Paul; Sniegowski, Paul

    2013-02-23

    Recent decades have seen a significant rise in studies in which evolution is observed and analysed directly-as it happens-under replicated, controlled conditions. Such 'experimental evolution' approaches offer a degree of resolution of evolutionary processes and their underlying genetics that is difficult or even impossible to achieve in more traditional comparative and retrospective analyses. In principle, experimental populations can be monitored for phenotypic and genetic changes with any desired level of replication and measurement precision, facilitating progress on fundamental and previously unresolved questions in evolutionary biology. Here, we summarize 10 invited papers in which experimental evolution is making significant progress on a variety of fundamental questions. We conclude by briefly considering future directions in this very active field of research, emphasizing the importance of quantitative tests of theories and the emerging role of genome-wide re-sequencing.

  7. Three-dimensional deployment of electro-dynamic tether via tension and current control with constraints

    Science.gov (United States)

    Wen, Hao; Jin, Dongping; Hu, Haiyan

    2016-12-01

    The concept of space tether has found a great deal of promising applications in space engineering. A prerequisite of any space tether mission is to deploy its tether to a commanded length. This paper aims to achieving the three-dimensional deployment of an electro-dynamic tether system in a propellant-free manner via the feedback control of the tension and electric current in the tether. The proposed controller is formulated in an analytical form with an extremely low level of computational load, and can explicitly account for the physical bounds of the tether tension and electric current by using a pair of strictly increasing saturation functions. In addition, the Lyapunov analysis is made to gain an insight into the stability characteristics of the proposed control strategy. To facilitate the theoretical analysis, the dynamic model of the system is developed under the widely used dumbbell assumption, along with the geomagnetic field modeled using a tilted dipole approximation. Finally, numerical case studies on a representative electro-dynamic tether system are conducted to evaluate the performance of the proposed controller and the influence of the actuating conditions and orbital inclinations.

  8. Constraints on top quark flavor changing neutral currents using diphoton events at the LHC

    Directory of Open Access Journals (Sweden)

    Sara Khatibi

    2016-08-01

    Full Text Available In this paper we show that the diphoton mass spectrum in proton–proton collisions at the LHC is sensitive to the top quark flavor changing neutral current in the vertices of tuγ and tcγ. The diphoton mass spectrum measured by the CMS experiment at the LHC at a center-of-mass energy of 8 TeV and an integrated luminosity of 19.5 fb−1 is used as an example to set limits on these FCNC couplings. It is also shown that the angular distribution of the diphotons is sensitive to anomalous tuγ and tcγ couplings and it is a powerful tool to probe any value of the branching fraction of top quark rare decay to an up-type quark plus a photon down to the order of 10−4.

  9. Analysis of environmental constraints on expanding reserves in current and future reservoirs in wetlands. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Harder, B.J.

    1995-03-01

    Louisiana wetlands require careful management to allow exploitation of non-renewable resources without destroying renewable resources. Current regulatory requirements have been moderately successful in meeting this goal by restricting development in wetland habitats. Continuing public emphasis on reducing environmental impacts of resource development is causing regulators to reassess their regulations and operators to rethink their compliance strategies. We examined the regulatory system and found that reducing the number of applications required by going to a single application process and having a coherent map of the steps required for operations in wetland areas would reduce regulatory burdens. Incremental changes can be made to regulations to allow one agency to be the lead for wetland permitting at minimal cost to operators. Operators need cost effective means of access that will reduce environmental impacts, decrease permitting time, and limit future liability. Regulators and industry must partner to develop incentive based regulations that can provide significant environmental impact reduction for minimal economic cost. In addition regulators need forecasts of future E&P trends to estimate the impact of future regulations. To determine future activity we attempted to survey potential operators when this approach was unsuccessful we created two econometric models of north and south Louisiana relating drilling activity, success ratio, and price to predict future wetland activity. Results of the econometric models indicate that environmental regulations have a small but statistically significant effect on drilling operations in wetland areas of Louisiana. We examined current wetland practices and evaluated those practices comparing environmental versus economic costs and created a method for ranking the practices.

  10. Plagioclase in Dacites of the Current Mt. St. Helens Eruption: Constraints for Magma Origin and Dynamics

    Science.gov (United States)

    Streck, M. J.; Broderick, C.; Thornber, C. R.; Clynne, M. A.; Pallister, J. S.

    2005-12-01

    The current, now year-long eruption of Mt. St. Helens is remarkable for a variety of reasons. Nearly solid, gas-poor dacite lava is extruding at the surface. Earthquakes are limited to the upper 3 km with most occurring less than 1 km below the surface; no deeper seismicity has been observed. Emissions of SO2, H2S, CO2 are extremely low, suggesting eruption of degassed magma. No direct evidence for mingling of more mafic magma has been observed. We investigated plagioclase crystals in 2004-5 dacite and 1980-86 dacite dome rocks to shed light on the nature and origin of the current magma. Polarized light and Nomarski microscopy in combination with detailed microprobe traverses were used to characterize single plagioclase crystals, focusing on areas near their rims. In addition, we mapped all plagioclase crystals within an area of ~1/3 of each thin section and grouped them according to easily distinguishable mineral features. Although labor-intensive, this new approach was devised to generate data statistically significant enough to compare plagioclase crystal populations of crystal-rich samples. Mappable features within crystals include: i) zones of acicular opx microlitic inclusions (commonly occurring near the rim), ii) resorption surfaces, iii) spatial association of i) and ii). Our key results from the crystal mapping indicate that sequential samples of 2004/5 have remained comparable, but are distinct from 1980-86 dacite dome samples. We interpret this result as strong evidence that the 2004-5 dacite is new magma and not 'left-over' 1980's dacite. The most interesting result from combining compositional profiling with texture is that acicular opx inclusions occur at the lowest observed An content of 40-33 regardless of position within crystal and that overgrowth on resorption surfaces are typically 10-20 mol% higher in An than within opx-rich zones resulting in single to multiple oscillations of An content towards the rim. These features could possibly be

  11. Applying experimental constraints to a one-dimensional model for BiS2 superconductivity

    Science.gov (United States)

    Griffith, M. A.; Foyevtsova, K.; Continentino, M. A.; Martins, G. B.

    2016-10-01

    Recent ARPES measurements [Sugimoto et al., Phys. Rev. B 92 (2015) 041113] have confirmed the one-dimensional character of the electronic structure of CeO0.5 F0.5 BiS2, a representative of BiS2-based superconductors. In addition, several members of this family present sizable increase in the superconducting transition temperature Tc under application of hydrostatic pressure. Motivated by these two results, we propose an effective one-dimensional three-orbital model, whose kinetic energy part, obtained through ab initio calculations, is supplemented by pair-scattering terms, which are treated at the mean-field level. We solve the gap equations self-consistently and then systematically probe which combination of pair-scattering terms gives results consistent with experiment, namely, a superconducting dome with a maximum Tc at the right chemical potential and a sizable increase in Tc when the magnitude of the hoppings is increased. For these constraints to be satisfied multi-gap superconductivity is required, in agreement with experiments, and one of the hoppings has a dominant influence over the increase of Tc with pressure.

  12. Current experimental situation in heavy-ion reactions

    Energy Technology Data Exchange (ETDEWEB)

    Scott, D.K.

    1978-06-01

    A detailed survey of the present experimental situation in heavy-ion physics is presented. The discussion begins by considering the simple excitation of discrete states in elastic scattering, transfer, and compound-nucleus reactions; it then turns to more drastic perturbations of the nucleus high in the continuum through fusion, fission, and deeply inelastic scattering, and concludes with the (possibly) limiting asymptotic phenomena of relativistic heavy-ion collisions. 138 figures, 5 tables, 451 references. (RWR)

  13. A structural model for Alzheimer's β-amyloid fibrils based on experimental constraints from solid state NMR

    Science.gov (United States)

    Petkova, Aneta T.; Ishii, Yoshitaka; Balbach, John J.; Antzutkin, Oleg N.; Leapman, Richard D.; Delaglio, Frank; Tycko, Robert

    2002-01-01

    We present a structural model for amyloid fibrils formed by the 40-residue β-amyloid peptide associated with Alzheimer's disease (Aβ1–40), based on a set of experimental constraints from solid state NMR spectroscopy. The model additionally incorporates the cross-β structural motif established by x-ray fiber diffraction and satisfies constraints on Aβ1–40 fibril dimensions and mass-per-length determined from electron microscopy. Approximately the first 10 residues of Aβ1–40 are structurally disordered in the fibrils. Residues 12–24 and 30–40 adopt β-strand conformations and form parallel β-sheets through intermolecular hydrogen bonding. Residues 25–29 contain a bend of the peptide backbone that brings the two β-sheets in contact through sidechain-sidechain interactions. A single cross-β unit is then a double-layered β-sheet structure with a hydrophobic core and one hydrophobic face. The only charged sidechains in the core are those of D23 and K28, which form salt bridges. Fibrils with minimum mass-per-length and diameter consist of two cross-β units with their hydrophobic faces juxtaposed. PMID:12481027

  14. Experimental constraints on the thermodynamics and sound velocities of hcp-Fe to core pressures

    Science.gov (United States)

    Murphy, Caitlin A.; Jackson, Jennifer M.; Sturhahn, Wolfgang

    2013-05-01

    We report the high-pressure thermoelastic and vibrational thermodynamic parameters for hexagonal close-packed iron (ɛ-Fe), based on nuclear resonant inelastic X-ray scattering and in situ X-ray diffraction experiments at 300 K. Long data collection times, high-energy resolution, and quasi-hydrostatic sample conditions produced a high-statistical quality data set that comprises the volume-dependent phonon density of states (DOS) of ɛ-Fe at eleven compression points. From the integrated phonon DOS, we determine the Lamb-Mössbauer factor (fLM), average force constant (Φ), and vibrational entropy (Svib) of ɛ-Fe to pressures relevant to Earth's outer core. We find fLM = 0.923 ± 0.001 at 171 GPa, suggesting restricted thermal atomic motion at large compressions. We use Φ to approximate ɛ-Fe's pressure- and temperature-dependent reduced isotopic partition function ratios (β-factors), which provide information about the partitioning behavior of iron isotopes in equilibrium processes involving solid ɛ-Fe. In addition, we use the volume dependence of Svib to determine the product of ɛ-Fe's vibrational thermal expansion coefficient and isothermal bulk modulus, which we find to be pressure-independent and equal to 5.70 ± 0.05 MPa/K at 300 K. Finally, from the low-energy region of each phonon DOS, we determine the Debye sound velocity (vD), from which we derive the compressional (vP) and shear (vS) sound velocities of ɛ-Fe. We find vD = 5.60 ± 0.06, vP = 10.11 ± 0.12, and vS = 4.99 ± 0.06 km/s at 171 GPa, thus providing a new tight constraint on the density dependence of ɛ-Fe's sound velocities to outer core pressures.

  15. Experimental Verification of Current Shear Design Equations for HSRC Beams

    Directory of Open Access Journals (Sweden)

    Attaullah Shah

    2012-07-01

    Full Text Available Experimental research on the shear capacity of HSRC (High Strength Reinforced Concrete beams is relatively very limited as compared to the NSRC (Normal Strength Reinforced Concrete beams. Most of the Building Codes determine the shear strength of HSRC with the help of empirical equations based on experimental work of NSRC beams and hence these equations are generally regarded as un-conservative for HSRC beams particularly at low level of longitudinal reinforcement. In this paper, 42 beams have been tested in two sets, such that in 21 beams no transverse reinforcement has been used, whereas in the remaining 21 beams, minimum transverse reinforcement has been used as per ACI-318 (American Concrete Institute provisions. Two values of compressive strength 52 and 61 MPa, three values of longitudinal steel ratio and seven values of shear span to depth ratio have been have been used. The beams were tested under concentrated load at the mid span. The results are compared with the equations proposed by different international building codes like ACI, AASHTO LRFD, EC (Euro Code, Canadian Code and Japanese Code for shear strength of HSRC beams.From comparison, it has been observed that some codes are less conservative for shear design of HSRC beams and further research is required to rationalize these equations.

  16. Experimental Study on Current Decay Characteristics of Persistent Current HTS Magnet by Alternating Magnetic Field

    Science.gov (United States)

    Park, Young Gun; Lee, Chang Young; Hwang, Young Jin; Lee, Woo Seung; Lee, Jiho; Jo, Hyun Chul; Chung, Yoon Do; Ko, Tae Kuk

    This paper deals with a current decay characteristics of a high temperature superconducting (HTS) magnet operated in persistent current mode (PCM). In superconducting synchronous machine applications such as linear synchronous motor (LSM), the superconducting coil is designed to operate in the PCM to obtain steady magnetic field with DC transport current. This superconducting magnet operates on a direct current, but it can be exposed to alternating magnetic field due to the armature winding. When the magnet is subjected to an external time-varying magnetic field, it is possible to result in a decay of the current in PCM system due to AC loss. In this research, a PCM system with armature coil which generates time-varying magnetic field was fabricated to verify current decay characteristics by external alternating magnetic field. The current decay rate was measured by using a hall sensor as functions of amplitude and frequency of armature coil.

  17. Wall conditioning for ITER: Current experimental and modeling activities

    Energy Technology Data Exchange (ETDEWEB)

    Douai, D., E-mail: david.douai@cea.fr [CEA, IRFM, Association Euratom-CEA, 13108 St. Paul lez Durance (France); Kogut, D. [CEA, IRFM, Association Euratom-CEA, 13108 St. Paul lez Durance (France); Wauters, T. [LPP-ERM/KMS, Association Belgian State, 1000 Brussels (Belgium); Brezinsek, S. [FZJ, Institut für Energie- und Klimaforschung Plasmaphysik, 52441 Jülich (Germany); Hagelaar, G.J.M. [Laboratoire Plasma et Conversion d’Energie, UMR5213, Toulouse (France); Hong, S.H. [National Fusion Research Institute, Daejeon 305-806 (Korea, Republic of); Lomas, P.J. [CCFE, Culham Science Centre, OX14 3DB Abingdon (United Kingdom); Lyssoivan, A. [LPP-ERM/KMS, Association Belgian State, 1000 Brussels (Belgium); Nunes, I. [Associação EURATOM-IST, Instituto de Plasmas e Fusão Nuclear, 1049-001 Lisboa (Portugal); Pitts, R.A. [ITER International Organization, F-13067 St. Paul lez Durance (France); Rohde, V. [Max-Planck-Institut für Plasmaphysik, 85748 Garching (Germany); Vries, P.C. de [ITER International Organization, F-13067 St. Paul lez Durance (France)

    2015-08-15

    Wall conditioning will be required in ITER to control fuel and impurity recycling, as well as tritium (T) inventory. Analysis of conditioning cycle on the JET, with its ITER-Like Wall is presented, evidencing reduced need for wall cleaning in ITER compared to JET–CFC. Using a novel 2D multi-fluid model, current density during Glow Discharge Conditioning (GDC) on the in-vessel plasma-facing components (PFC) of ITER is predicted to approach the simple expectation of total anode current divided by wall surface area. Baking of the divertor to 350 °C should desorb the majority of the co-deposited T. ITER foresees the use of low temperature plasma based techniques compatible with the permanent toroidal magnetic field, such as Ion (ICWC) or Electron Cyclotron Wall Conditioning (ECWC), for tritium removal between ITER plasma pulses. Extrapolation of JET ICWC results to ITER indicates removal comparable to estimated T-retention in nominal ITER D:T shots, whereas GDC may be unattractive for that purpose.

  18. Experimental investigation of current free double layers in helicon plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Sahu, B. B. [Department of Applied Sciences and Humanities, Dronacharya College of Engineering, Gurgaon 123506 (India); Tarey, R. D. [Department of Physics, Indian Institute of Technology, New Delhi 110016 (India); Ganguli, A. [Centre for Energy Studies, Indian Institute of Technology, New Delhi 110016 (India)

    2014-02-15

    The paper presents investigations of current free double layer (CFDL) that forms in helicon plasmas. In contrast to the other work reporting on the same subject, in the present investigations the double layer (DL) forms in a mirror-like magnetic field topology. The RF compensated Langmuir probe measurements show multiple DLs, which are in connection with, the abrupt fall of densities along with potential drop of about 24 V and 18 V. The DLs strengths (e ΔV{sub p})/(k T{sub e}) are about 9.5 and 6, and the corresponding widths are about 6 and 5 D lengths. The potential drop is nearly equal to the thermal anisotropies between the two plasma regions forming the DL, which is present in the plateau region of mirror, unlike the earlier studies on the DL formation in the region of strong gradients in the magnetic field. Also, it presents a qualitative discussion on the mechanism of DL formation.

  19. Experimental constraints on the electrical anisotropy of the lithosphere-asthenosphere system.

    Science.gov (United States)

    Pommier, Anne; Leinenweber, Kurt; Kohlstedt, David L; Qi, Chao; Garnero, Edward J; Mackwell, Stephen J; Tyburczy, James A

    2015-06-11

    The relative motion of lithospheric plates and underlying mantle produces localized deformation near the lithosphere-asthenosphere boundary. The transition from rheologically stronger lithosphere to weaker asthenosphere may result from a small amount of melt or water in the asthenosphere, reducing viscosity. Either possibility may explain the seismic and electrical anomalies that extend to a depth of about 200 kilometres. However, the effect of melt on the physical properties of deformed materials at upper-mantle conditions remains poorly constrained. Here we present electrical anisotropy measurements at high temperatures and quasi-hydrostatic pressures of about three gigapascals on previously deformed olivine aggregates and sheared partially molten rocks. For all samples, electrical conductivity is highest when parallel to the direction of prior deformation. The conductivity of highly sheared olivine samples is ten times greater in the shear direction than for undeformed samples. At temperatures above 900 degrees Celsius, a deformed solid matrix with nearly isotropic melt distribution has an electrical anisotropy factor less than five. To obtain higher electrical anisotropy (up to a factor of 100), we propose an experimentally based model in which layers of sheared olivine are alternated with layers of sheared olivine plus MORB or of pure melt. Conductivities are up to 100 times greater in the shear direction than when perpendicular to the shear direction and reproduce stress-driven alignment of the melt. Our experimental results and the model reproduce mantle conductivity-depth profiles for melt-bearing geological contexts. The field data are best fitted by an electrically anisotropic asthenosphere overlain by an isotropic, high-conductivity lowermost lithosphere. The high conductivity could arise from partial melting associated with localized deformation resulting from differential plate velocities relative to the mantle, with subsequent upward melt percolation

  20. Experimental constraints on shock-induced microstructures in naturally deformed silicates

    Science.gov (United States)

    Huffman, Alan R.; Reimold, W. Uwe

    1996-05-01

    Planar deformation features (PDFs) in various minerals have long been accepted as evidence of impact-induced deformation. The uniqueness of this association was challenged in the context of the {K}/{T} Boundary extinction debate, after mosaicism and microstructures similar to PDFs were reported from the products of explosive volcanism. As a result of this debate, a significant volume of new experimental and observational data on the development of shock-induced microstructures has become available over the last ten years. The results reveal that factors such as pre-shock temperature, pulse duration, and crystallographic orientation of target minerals to the shock wave have a primary influence on how these microstructures develop. Data from diamond anvil cell and high-pressure friction experiments reveal that the same solid-state amorphization process that produces shock-induced PDFs at low temperatures also occurs at much lower strain rates in static experiments. The experimental data indicate that the amorphization process is thermally activated and that the character of the resulting PDFs is a function of the applied strain rate. Shock-induced amorphization occurs along those crystallographic planes that are most readily transformed to the high-pressure phase during very short pulse durations and produces PDFs that are visible at the optical scale. Lower strain rate deformation produces TEM scale amorphization with orientations that are more homogeneously distributed throughout the target mineral and produces no optically visible PDFs. The data confirm the uniqueness of multiple intersecting sets of optically visible PDFs as a diagnostic indicator of hypervelocity impact. The data also support the hypothesis that the amorphization process can occur at a wide range of strain rates, and that the limiting pressure for the process is controlled by the phase stability of the target mineral under the applied loading conditions, not by the HEL. The data also suggest

  1. Experimental constraints on the solidification of a nominally dry lunar magma ocean

    Science.gov (United States)

    Lin, Yanhao; Tronche, Elodie J.; Steenstra, Edgar S.; van Westrenen, Wim

    2017-08-01

    The lunar magma ocean (LMO) concept has been used extensively for lunar evolution models for decades, but to date the full cooling and crystallization path of the LMO has not been studied experimentally. Here we present results of a high-pressure, high-temperature experimental study of the mineralogical and geochemical evolution accompanying the full solidification of a nominally dry LMO. Experiments used a bulk composition based on geophysical data, and assumed an initial LMO depth of 700 km. The effect of pressure within a deep magma ocean on solidification at different levels in the ocean was explicitly taken into account, by performing experiments at multiple pressures and constant temperature during each solidification step. Results show formation of a deep harzburgite (olivine + low-Ca pyroxene) layer in the first ∼50% of equilibrium crystallization. The crystallising mineral assemblage does not change until plagioclase and clinopyroxene appear at 68 PCS (per cent solid by volume), while low-Ca pyroxene stops forming. Olivine disappears at 83 PCS, and ilmenite and β-quartz start crystallizing at 91 and 96 PCS, respectively. At 99 PCS, we observe an extremely iron-rich (26.5 wt.% FeO) residual LMO liquid. Our results differ substantially from the oft-cited LMO solidification study of Snyder et al. (1992), which was based on a limited number of experiments at a single pressure. Differences include the mineralogy of the deepest sections of the solidified LMO (harzburgitic instead of dunitic), the formation of SiO2 in the lunar interior, and the development of extreme iron enrichment in the last remaining dregs of the LMO. Our findings shed new light on several aspects of lunar petrology, including the formation of felsic and iron-rich magmas in the Moon. Finally, based on our experiments the lunar crust, consisting of the light minerals plagioclase and quartz, would reach a thickness of ∼67.5 km. This is far greater than crustal thickness estimates from

  2. Realizing life-scalable experimental pyroclastic density currents

    Science.gov (United States)

    Cronin, S. J.; Lube, G.; Breard, E.; Jones, J.; Valentine, G.; Freundt, A.; Hort, M. K.; Bursik, M. I.

    2013-12-01

    Pyroclastic Density Currents (PDCs) - the most deadly threat from volcanoes - are extremely hot, ground-hugging currents of rock fragments and gas that descend slopes at hundreds of kilometers per hour. These hostile flows are impossible to internally measure, thus volcanologists are persistently blocked in efforts to realistically forecast their internal mechanics and hazards. Attempts to fill this gap via laboratory-scale experiments continue to prove difficult, because they usually mismatch the dynamic and kinematic scaling of real-world flows by several orders of magnitude. In a multi-institutional effort, the first large-scale pyroclastic flow generator that can synthesize repeatable hot high-energy gas-particle mixture flows in safety has been commissioned in New Zealand. The final apparatus stands 15 m high, consisting of a tower/elevator system; an instrumented hopper that can hold >6000 kg (or 3.2 m3) of natural volcanic materials, which can be discharged at a range of controlled rates onto an instrumented, variably inclinable (6-25°) glass-sided chute for examining the vertical profiles of PDCs in motion. The use of rhyolitic pyroclastic material from the 1800 AD Taupo Eruption (with its natural grain-size, sorting and shape characteristics) and gas ensures natural coupling between the solids and fluid phases. PDC analogues with runout of >15 meters and flow depths of 1.5-6 meters are created by generating variably heated falling columns of natural volcanic particles (50-1300 kg/s), dispersed and aerated to controlled particle densities between 3 and 60 vol.% at the base of the elevated hopper. The descending columns rapidly generate high-velocity flows (up to 14 m/s) once impacting on the inclined channel, reproducing many features of natural flows, including segregation into dense and dilute regimes, progressive aggradational and en masse deposition of particles and the development of high internal gas-pore-pressures during flow. The PDC starting

  3. Bioremediating oil spills in nutrient poor ocean waters using fertilized clay mineral flakes: some experimental constraints.

    Science.gov (United States)

    Warr, Laurence N; Friese, André; Schwarz, Florian; Schauer, Frieder; Portier, Ralph J; Basirico, Laura M; Olson, Gregory M

    2013-01-01

    Much oil spill research has focused on fertilizing hydrocarbon oxidising bacteria, but a primary limitation is the rapid dilution of additives in open waters. A new technique is presented for bioremediation by adding nutrient amendments to the oil spill using thin filmed minerals comprised largely of Fullers Earth clay. Together with adsorbed N and P fertilizers, filming additives, and organoclay, clay flakes can be engineered to float on seawater, attach to the oil, and slowly release contained nutrients. Our laboratory experiments of microbial activity on weathered source oil from the Deepwater Horizon spill in the Gulf of Mexico show fertilized clay treatment significantly enhanced bacterial respiration and consumption of alkanes compared to untreated oil-in-water conditions and reacted faster than straight fertilization. Whereas a major portion (up to 98%) of the alkane content was removed during the 1 month period of experimentation by fertilized clay flake interaction; the reduced concentration of polyaromatic hydrocarbons was not significantly different from the non-clay bearing samples. Such clay flake treatment could offer a way to more effectively apply the fertilizer to the spill in open nutrient poor waters and thus significantly reduce the extent and duration of marine oil spills, but this method is not expected to impact hydrocarbon toxicity.

  4. Bioremediating Oil Spills in Nutrient Poor Ocean Waters Using Fertilized Clay Mineral Flakes: Some Experimental Constraints

    Directory of Open Access Journals (Sweden)

    Laurence N. Warr

    2013-01-01

    Full Text Available Much oil spill research has focused on fertilizing hydrocarbon oxidising bacteria, but a primary limitation is the rapid dilution of additives in open waters. A new technique is presented for bioremediation by adding nutrient amendments to the oil spill using thin filmed minerals comprised largely of Fullers Earth clay. Together with adsorbed N and P fertilizers, filming additives, and organoclay, clay flakes can be engineered to float on seawater, attach to the oil, and slowly release contained nutrients. Our laboratory experiments of microbial activity on weathered source oil from the Deepwater Horizon spill in the Gulf of Mexico show fertilized clay treatment significantly enhanced bacterial respiration and consumption of alkanes compared to untreated oil-in-water conditions and reacted faster than straight fertilization. Whereas a major portion (up to 98% of the alkane content was removed during the 1 month period of experimentation by fertilized clay flake interaction; the reduced concentration of polyaromatic hydrocarbons was not significantly different from the non-clay bearing samples. Such clay flake treatment could offer a way to more effectively apply the fertilizer to the spill in open nutrient poor waters and thus significantly reduce the extent and duration of marine oil spills, but this method is not expected to impact hydrocarbon toxicity.

  5. Experimental constraints on the origin of in-situ shattered dolostones

    Science.gov (United States)

    Fondriest, Michele; Doan, Mai-Lihn; Di Toro, Giulio; Fusseis, Florian

    2015-04-01

    Many seismically active regions on Earth include thick sequences (up to 4-10 km) of sedimentary carbonate-bearing rocks (mainly limestones and dolostones) in the brittle upper crust. This implies that most moderate to large in size earthquakes (e.g. L'Aquila 2009 Mw = 6.1 in central Italy) and their aftershocks, nucleate within and propagate through carbonate rocks. In the last years several field and experimental studies focused on the characterization of carbonate-bearing fault zone rocks to determine earthquake-related deformation processes. In particular, the occurrence of thick belts (10-100s m) of low-strain fault-related breccias (average size of rock fragments >1 cm), which is relatively common within carbonate-bearing damage zones, was generally interpreted as resulting from quasi-static growth of the fault zones (e.g. Billi et al., 2003; Salvini et al., 1999) rather than from the cumulative effect of multiple earthquake ruptures. Here we report the occurrence of up to hundreds of meters thick belts of intensely fragmented dolostones along the major transpressive Foiana Fault Zone (FFZ, Italian Southern Alps) which was exhumed from 1.5-2 km depth. Such dolostones are reduced into fragments ranging from few centimeters down to few millimeters in size and are reduced to ultrafine-grained layers in proximity to the principal slipping zones. Preservation of the original bedding indicates a lack of significant shear strain in the fragmented dolostones which seem to have been shattered in situ. To understand the origin of the in-situ shattered rocks, dolostones of the Mendola Formation (i.e. host rock of the FFZ) were deformed in uniaxial compression both under low-strain rate (~10-3 s-1) quasi-static loading and high-strain rate (>50 s-1) dynamic loading. Dolostones deformed up to failure under low-strain rate loading were affected by single to multiple discrete (i.e. not interconnected) extensional fractures sub-parallel to the loading direction. Dolostones

  6. Experimental Constraints on a Dark Matter Origin for the DAMA Annual Modulation Effect

    Energy Technology Data Exchange (ETDEWEB)

    Aalseth, Craig E.; Barbeau, Phil; Cerdeno, D. G.; Colaresi, J.; Collar, J. I.; de Lurgio, P.; Drake, G.; Fast, James E.; Greenberg, C.; Hossbach, Todd W.; Kephart, Jeremy D.; Marino, Michael G.; Miley, Harry S.; Orrell, John L.; Reyna, D.; Robertson, R. G. H.; Talaga, R. L.; Tench, O.; Van Wechel, T. D.; Wilkerson, J.; Yocum, K. M.

    2008-12-17

    Abstract Follows: C. E. Aalseth,1 P. S. Barbeau,2 D. G. Cerdeño,3 J. Colaresi,4 J. I. Collar,2 P. de Lurgio,5 G. Drake,5 J. E. Fast,1 C. H. Greenberg,2 T. W. Hossbach,1 J. D. Kephart,1 M. G. Marino,7 H. S. Miley,1 J. L. Orrell,1 D. Reyna,6 R. G. H. Robertson,7 R. L. Talaga,5 O. Tench,4 T. D. Van Wechel,7 J. F. Wilkerson,7 and K. M. Yocum4 (CoGeNT Collaboration) 1Pacific Northwest National Laboratory, Richland, Washington 99352, USA 2Kavli Institute for Cosmological Physics and Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA 3Departamento de Física Teórica C-XI & Instituto de Física Teórica UAM-CSIC, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain 4CANBERRA Industries, Meriden, Connecticut 06450, USA 5Argonne National Laboratory, Argonne, Illinois 60439, USA 6Sandia National Laboratories, Livermore, California 94550, USA 7Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, Washington 98195, USA Received 7 July 2008; revised 6 August 2008; published 17 December 2008 A claim for evidence of dark matter interactions in the DAMA experiment has been recently reinforced. We employ a new type of germanium detector to conclusively rule out a standard isothermal galactic halo of weakly interacting massive particles as the explanation for the annual modulation effect leading to the claim. Bounds are similarly imposed on a suggestion that dark pseudoscalars might lead to the effect. We describe the sensitivity to light dark matter particles achievable with our device, in particular, to next-to-minimal supersymmetric model candidates.

  7. Experimental Constraints on the Partitioning and Valence of V and Cr in Garnet and Coexisting Glass

    Science.gov (United States)

    Righter, K.; Sutton, S.; Berthet, S.; Newville, M.

    2008-01-01

    A series of experiments with garnet and coexisting melt have been carried out across a range of oxygen fugacities (near hematite-magnetite (HM) to below the iron-wustite (IW) buffers) at 1.7 GPa to study the partitioning and valence of Cr and V in both phases. Experiments were carried out in a non end loaded piston cylinder apparatus, and the run products were analyzed with electron microprobe and xray absorption near edge structure (XANES) analysis at beamline 13-ID at the Advanced Photon Source of Argonne National Lab. The valence of vanadium and chromium were determined using the position and intensity of the Ka pre-edge peaks, calibrated on a series of Cr and Vbearing standard glasses. This technique has been applied to V and Cr in glasses and V in spinels previously, and in these isotropic phases there are no orientational effects on the XANES spectra (Righter et al., 2006, Amer. Mineral. 91, 1643-1656). We also now demonstrate this to be true for V and Cr in garnet. Also, previous work has shown that V has a higher valence in the glass (or melt) than in the coexisting spinel. This is also true for V in garnet-glass pairs in this study. Vanadium valence in garnets varies from 2.7 below the IW buffer to 3.7 near HM, and for coexisting glass it varies from 3.2 to 4.3. Vanadium valence measured in some natural garnets from mantle localities indicates V in the more reduced range at 2.5. Comparisons will be made between fO2 estimated from V valence and other methods for garnet-bearing mantle samples. In contrast, Cr valence measured in garnet and coexisting glass for all experimental and natural samples is 2.9- 3.0, suggesting that the valence of Cr does not vary within either phase across a large fO2 range. These results demonstrate that while V varies from 2+ to 3+ to 4+ in garnet-melt systems, Cr does not, and this will ultimately affect the partitioning behavior of these two elements in natural systems. Garnet/melt D(Cr) are between 12 and 17 across this range

  8. Experimental Constraints on Microbial Liberation of Structural Iron from Common Clay Minerals in Marine Sediments

    Science.gov (United States)

    Metcalfe, K. S.; Gaines, R. R.; Trang, J.; Scott, S. W.; Crane, E. J.; Lackey, J.; Prokopenko, M. G.; Berelson, W.

    2013-12-01

    Iron is a limiting nutrient in many marine settings. The marine Fe-cycle is complex because Fe may be used as an electron donor or acceptor and cycled many times before ultimate burial in sediments. Thus, the availability of iron plays a large role in the marine carbon cycle, influencing not only the extent of primary productivity but also the oxidation of organic matter in sediments. The primary constituents of marine sediments are clay minerals, which commonly contain lattice-bound Fe in octahedral sites. In marine settings, the pool of Fe bound within silicate mineral lattices has long been considered reactive only over long timescales, and thus non-bioavailable. In vitro experimental evidence has shown that lab cultures of Fe-reducing bacteria are able to utilize structurally-bound Fe (III) from the crystal lattice of nontronite, an uncommon but particularly Fe-rich (> 12 wt.%) smectite. Importantly, this process is capable of liberating Fe (II) to solution, where it is available to biotic processes as an electron donor. In order to constrain the capacity of naturally-occurring marine bacteria to liberate structurally-coordinated Fe from the lattices of common clay minerals, we exposed a suite of 16 different clay minerals (0.8-13.9 wt.% Fe) to lab cultures of known Fe-reducer S. onenidensis MR-1 and to a natural consortium of Fe-reducing microbes from the San Pedro and Santa Monica Basins over timescales ranging from 7-120 days. Clay minerals were treated with Na-dithionite to extract surface-bound Fe prior to exposure. Crystallographic data and direct measurements of Fe in solution demonstrate the release of structural Fe from all clay minerals analyzed. Neoformation of illite and amorphous quartz were observed. The array of clay minerals and microbes used in this experiment complement past findings and suggest that common clay minerals may represent a large and previously unrecognized pool of bioavailable Fe in the world ocean that contributes significantly

  9. Experimental Investigations of Halogen and Noble Gas Geochemistry as Constraints on Planetary Outgassing

    Science.gov (United States)

    Musselwhite, D. S.; Drake, M. J.; Swindle, T. D.

    1992-07-01

    Introduction The ^129Xe/^132Xe ratio in Mid-Ocean Ridge Basalts (MORBs) is higher than in the atmosphere and Ocean Island Basalts. Enhanced ^129Xe/^132Xe ratios are widely regarded to be the result of ^129I decay (t(sub)1/2 = 16 m.y.) early in solar system history (e.g. Swindle et al., 1986). Allegre et al. (1983, 1988) proposed a catastrophic degassing scheme to explain this excess. Both Musselwhite et al. (1990) and Hiyagon and Ozima (1990) have noted that because mineral/melt partition coefficients (D) for I appear lower than for Xe, the I/Xe ratio may not be enhanced in the mantle by mineral/melt fractionation. Musselwhite et al. (1990) proposed recycling of I back into the mantle following outgassing, and Hiyagon and Ozima (1990) proposed impact degassing of the mantle as a way around this problem. Knowledge of the relative values of D(I) and D(Xe) is important to the discussion of early planetary outgassing models. Although the dataset for D(I) values is not complete, the known values so far are uniformly low. The dataset for Xe on the other hand is quite ambiguous. Experimentally determined values for D(Xe) vary widely--ranging from 0.05 to >> 1 (Hiyagon and Ozima, 1986; Broadhurst et al., 1992), and it is unclear which of the values is the geologically significant one. Particularly important is the question of whether D(Xe) is greater than or less than unity. Partitioning Experiments: We have undertaken to simultaneously determine the D(I) and D(Ar) values directly, then calculate the D(Xe) from D(Ar). This approach is possible because experiments investigating the mineral/melt partitioning of noble gases, while not consistent in an absolute sense between experiments, do display a consistent trend with the lightest noble gases being most incompatible and Xe most compatible. We are adapting our technique to determine D(Kr) and D(Xe) directly. Finely crushed silica glass (~100 micrometer grain size) was placed in a gas pressure vessel. The vessel was

  10. Currents, HF Radio-derived, Monterey Bay, 1 hr, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 1 hour average of the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN EXPERIMENTAL...

  11. Currents, HF Radio-derived, SF Bay, 1 hr, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 1 hour average of the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN EXPERIMENTAL...

  12. Currents, HF Radio-derived, SF Bay Outlet, 1 hr, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 1 hour average of the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN EXPERIMENTAL...

  13. Currents, HF Radio-derived, SF Bay Outlet, 1 hr, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 1 hour average of the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN EXPERIMENTAL...

  14. Currents, HF Radio-derived, Bodega Bay, 1 hr, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 1 hour average of the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN EXPERIMENTAL...

  15. Currents, HF Radio-derived, Bodega Bay, 1 hr, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 1 hour average of the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN EXPERIMENTAL...

  16. Currents, HF Radio-derived, Ano Nuevo, 1 hr, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 1 hour average of the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN EXPERIMENTAL...

  17. Currents, HF Radio-derived, Ano Nuevo, 1 hr, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 1 hour average of the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN EXPERIMENTAL...

  18. Glass Property Models and Constraints for Estimating the Glass to be Produced at Hanford by Implementing Current Advanced Glass Formulation Efforts

    Energy Technology Data Exchange (ETDEWEB)

    Vienna, John D.; Kim, Dong-Sang; Skorski, Daniel C.; Matyas, Josef

    2013-07-31

    Recent glass formulation and melter testing data have suggested that significant increases in waste loading in HLW and LAW glasses are possible over current system planning estimates. The data (although limited in some cases) were evaluated to determine a set of constraints and models that could be used to estimate the maximum loading of specific waste compositions in glass. It is recommended that these models and constraints be used to estimate the likely HLW and LAW glass volumes that would result if the current glass formulation studies are successfully completed. It is recognized that some of the models are preliminary in nature and will change in the coming years. Plus the models do not currently address the prediction uncertainties that would be needed before they could be used in plant operations. The models and constraints are only meant to give an indication of rough glass volumes and are not intended to be used in plant operation or waste form qualification activities. A current research program is in place to develop the data, models, and uncertainty descriptions for that purpose. A fundamental tenet underlying the research reported in this document is to try to be less conservative than previous studies when developing constraints for estimating the glass to be produced by implementing current advanced glass formulation efforts. The less conservative approach documented herein should allow for the estimate of glass masses that may be realized if the current efforts in advanced glass formulations are completed over the coming years and are as successful as early indications suggest they may be. Because of this approach there is an unquantifiable uncertainty in the ultimate glass volume projections due to model prediction uncertainties that has to be considered along with other system uncertainties such as waste compositions and amounts to be immobilized, split factors between LAW and HLW, etc.

  19. Glass Property Models and Constraints for Estimating the Glass to be Produced at Hanford by Implementing Current Advanced Glass Formulation Efforts

    Energy Technology Data Exchange (ETDEWEB)

    Vienna, John D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kim, Dong-Sang [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Skorski, Daniel C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Matyas, Josef [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2013-07-01

    Recent glass formulation and melter testing data have suggested that significant increases in waste loading in HLW and LAW glasses are possible over current system planning estimates. The data (although limited in some cases) were evaluated to determine a set of constraints and models that could be used to estimate the maximum loading of specific waste compositions in glass. It is recommended that these models and constraints be used to estimate the likely HLW and LAW glass volumes that would result if the current glass formulation studies are successfully completed. It is recognized that some of the models are preliminary in nature and will change in the coming years. Plus the models do not currently address the prediction uncertainties that would be needed before they could be used in plant operations. The models and constraints are only meant to give an indication of rough glass volumes and are not intended to be used in plant operation or waste form qualification activities. A current research program is in place to develop the data, models, and uncertainty descriptions for that purpose. A fundamental tenet underlying the research reported in this document is to try to be less conservative than previous studies when developing constraints for estimating the glass to be produced by implementing current advanced glass formulation efforts. The less conservative approach documented herein should allow for the estimate of glass masses that may be realized if the current efforts in advanced glass formulations are completed over the coming years and are as successful as early indications suggest they may be. Because of this approach there is an unquantifiable uncertainty in the ultimate glass volume projections due to model prediction uncertainties that has to be considered along with other system uncertainties such as waste compositions and amounts to be immobilized, split factors between LAW and HLW, etc.

  20. Current transformers with nanocrystalline alloy toroidal core: analytical, computational and experimental studies

    Directory of Open Access Journals (Sweden)

    Benedito Antonio Luciano

    2012-10-01

    Full Text Available In this paper are presented theoretical analysis and experimental results concerning the performance of toroidal cores used in current transformers. For most problems concerning transformers design, analytical methods are useful, but numerical methods provide a better understanding of the transformers electromagnetic behaviour. Numerical field solutions may be used to determine the electrical equivalent circuit parameters of toroidal core current transformers. Since the exciting current of current transformers alters the ratio and phase angle of primary and secondary currents, it is made as small as possible though the use of high permeability and low loss magnetic material in the construction of the core. According to experimental results presented in this work, in comparison with others soft magnetic materials, nanocrystalline alloys appear as the best material to be used in toroidal core for current transformers.

  1. Flux quantum tunneling effect and its influence on the experimental critical current density

    Institute of Scientific and Technical Information of China (English)

    闻海虎; 赵忠贤; GriessenR.

    1995-01-01

    By using magnetic sweeping method, the temperature and magnetic field dependencies of the experimental current density and the normalized relaxation rate have been obtained. The true critical current density corresponding to the zero activation energy has been carried out based on the collective-pinning and the thermally-activated flux motion models, and therefore the influences of the quantum tunneling effect and the thermal activation effect on the experimental critical current density are distinguished. It is found that, with temperature lower than 10 K, the relaxation rate will not drop to zero when T approaches zero K because of the occurrence of the flux quantum tunneling. This additional flux motion further reduces the experimental critical current density j making it saturated with lowering temperature.

  2. Experimental study of yttrium barium copper oxide superconducting tape’s critical current under twisting moment

    Indian Academy of Sciences (India)

    Ziauddin Khan; Ananya Kundu; Subrata Pradhan

    2013-10-01

    Critical current (c) characteristics of 2G YBCO superconducting tape under the influence of twisting moment was experimentally investigated at varying current ramp rates in the self-field. Under a uniform twist, the degradation in the current-carrying capacity of YBCO tape up to 30% was observed at 77 K. The degradation is largely attributed to the shear stress and torsional shear strain resulting from the twisting. The superconductor to resistive transition index, , is also found to behave in an identical manner with increase in the twisting. Finite element analysis (FEA) of the tape in the experimental configuration with twisting moment being applied on to it has been carried out in COMSOL. The torsional strain calculated analytically as per the experimental configuration matches closely with that of FEA results, which shows that the critical current degradation is a function of strain.

  3. Constraint-Induced Movement Therapy Combined with Transcranial Direct Current Stimulation over Premotor Cortex Improves Motor Function in Severe Stroke: A Pilot Randomized Controlled Trial

    Science.gov (United States)

    Batista, Larissa M.; Nogueira, Lídia L. R. F.; de Oliveira, Eliane A.; de Carvalho, Antonio G. C.; Lima, Soriano S.; Santana, Jordânia R. M.; de Lima, Emerson C. C.; Fernández-Calvo, Bernardino

    2017-01-01

    Objective. We compared the effects of transcranial direct current stimulation at different cortical sites (premotor and motor primary cortex) combined with constraint-induced movement therapy for treatment of stroke patients. Design. Sixty patients were randomly distributed into 3 groups: Group A, anodal stimulation on premotor cortex and constraint-induced movement therapy; Group B, anodal stimulation on primary motor cortex and constraint-induced movement therapy; Group C, sham stimulation and constraint-induced movement therapy. Evaluations involved analysis of functional independence, motor recovery, spasticity, gross motor function, and muscle strength. Results. A significant improvement in primary outcome (functional independence) after treatment in the premotor group followed by primary motor group and sham group was observed. The same pattern of improvement was highlighted among all secondary outcome measures regarding the superior performance of the premotor group over primary motor and sham groups. Conclusions. Premotor cortex can contribute to motor function in patients with severe functional disabilities in early stages of stroke. This study was registered in ClinicalTrials.gov database (NCT 02628561). PMID:28250992

  4. Constraint-Induced Movement Therapy Combined with Transcranial Direct Current Stimulation over Premotor Cortex Improves Motor Function in Severe Stroke: A Pilot Randomized Controlled Trial.

    Science.gov (United States)

    Andrade, Suellen M; Batista, Larissa M; Nogueira, Lídia L R F; de Oliveira, Eliane A; de Carvalho, Antonio G C; Lima, Soriano S; Santana, Jordânia R M; de Lima, Emerson C C; Fernández-Calvo, Bernardino

    2017-01-01

    Objective. We compared the effects of transcranial direct current stimulation at different cortical sites (premotor and motor primary cortex) combined with constraint-induced movement therapy for treatment of stroke patients. Design. Sixty patients were randomly distributed into 3 groups: Group A, anodal stimulation on premotor cortex and constraint-induced movement therapy; Group B, anodal stimulation on primary motor cortex and constraint-induced movement therapy; Group C, sham stimulation and constraint-induced movement therapy. Evaluations involved analysis of functional independence, motor recovery, spasticity, gross motor function, and muscle strength. Results. A significant improvement in primary outcome (functional independence) after treatment in the premotor group followed by primary motor group and sham group was observed. The same pattern of improvement was highlighted among all secondary outcome measures regarding the superior performance of the premotor group over primary motor and sham groups. Conclusions. Premotor cortex can contribute to motor function in patients with severe functional disabilities in early stages of stroke. This study was registered in ClinicalTrials.gov database (NCT 02628561).

  5. Constraint-Induced Movement Therapy Combined with Transcranial Direct Current Stimulation over Premotor Cortex Improves Motor Function in Severe Stroke: A Pilot Randomized Controlled Trial

    Directory of Open Access Journals (Sweden)

    Suellen M. Andrade

    2017-01-01

    Full Text Available Objective. We compared the effects of transcranial direct current stimulation at different cortical sites (premotor and motor primary cortex combined with constraint-induced movement therapy for treatment of stroke patients. Design. Sixty patients were randomly distributed into 3 groups: Group A, anodal stimulation on premotor cortex and constraint-induced movement therapy; Group B, anodal stimulation on primary motor cortex and constraint-induced movement therapy; Group C, sham stimulation and constraint-induced movement therapy. Evaluations involved analysis of functional independence, motor recovery, spasticity, gross motor function, and muscle strength. Results. A significant improvement in primary outcome (functional independence after treatment in the premotor group followed by primary motor group and sham group was observed. The same pattern of improvement was highlighted among all secondary outcome measures regarding the superior performance of the premotor group over primary motor and sham groups. Conclusions. Premotor cortex can contribute to motor function in patients with severe functional disabilities in early stages of stroke. This study was registered in ClinicalTrials.gov database (NCT 02628561.

  6. Performance of current measurement system in poloidal field power supply for Experimental Advanced Superconducting Tokamak

    Science.gov (United States)

    Liu, D. M.; Li, J.; Wan, B. N.; Lu, Z.; Wang, L. S.; Jiang, L.; Lu, C. H.; Huang, J.

    2016-11-01

    As one of the core subsystems of the Experimental Advanced Superconducting Tokamak (EAST), the poloidal field power system supplies energy to EAST's superconducting coils. To measure the converter current in the poloidal field power system, a current measurement system has been designed. The proposed measurement system is composed of a Rogowski coil and a newly designed integrator. The results of the resistor-inductor-capacitor discharge test and the converter equal current test show that the current measurement system provides good reliability and stability, and the maximum error of the proposed system is less than 1%.

  7. Experimental identification of an azimuthal current in a magnetic nozzle of a radiofrequency plasma thruster

    Science.gov (United States)

    Takahashi, Kazunori; Chiba, Aiki; Komuro, Atsushi; Ando, Akira

    2016-10-01

    The azimuthal plasma current in a magnetic nozzle of a radiofrequency plasma thruster is experimentally identified by measuring the plasma-induced magnetic field. The axial plasma momentum increases over about 20 cm downstream of the thruster exit due to the Lorentz force arising from the azimuthal current. The measured current shows that the azimuthal current is given by the sum of the electron diamagnetic drift and \\mathbf{E}× \\mathbf{B} drift currents, where the latter component decreases with an increase in the magnetic field strength; hence the azimuthal current approaches the electron diamagnetic drift one for the strong magnetic field. The Lorentz force calculated from the measured azimuthal plasma current and the radial magnetic field is smaller than the directly measured force exerted to the magnetic field, which indicates the existence of a non-negligible Lorentz force in the source tube.

  8. Water-waves on linear shear currents. A comparison of experimental and numerical results.

    Science.gov (United States)

    Simon, Bruno; Seez, William; Touboul, Julien; Rey, Vincent; Abid, Malek; Kharif, Christian

    2016-04-01

    Propagation of water waves can be described for uniformly sheared current conditions. Indeed, some mathematical simplifications remain applicable in the study of waves whether there is no current or a linearly sheared current. However, the widespread use of mathematical wave theories including shear has rarely been backed by experimental studies of such flows. New experimental and numerical methods were both recently developed to study wave current interactions for constant vorticity. On one hand, the numerical code can simulate, in two dimensions, arbitrary non-linear waves. On the other hand, the experimental methods can be used to generate waves with various shear conditions. Taking advantage of the simplicity of the experimental protocol and versatility of the numerical code, comparisons between experimental and numerical data are discussed and compared with linear theory for validation of the methods. ACKNOWLEDGEMENTS The DGA (Direction Générale de l'Armement, France) is acknowledged for its financial support through the ANR grant N° ANR-13-ASTR-0007.

  9. Geochemical Controls on the Mobility of Cu and Fe in Hydrothermal Vent Fluids at Mid-Ocean Ridges: Experimental and Theoretical Constraints

    Science.gov (United States)

    Schaen, A. T.; Tutolo, B. M.; Seyfried, W. E.

    2012-12-01

    It has long been recognized that MOR hydrothermal vent fluids are characterized by variably high concentrations of dissolved transition metals. These metalliferous fluids play a role in the formation of seafloor massive sulfide deposits, serving as analogues for similar deposits on land, while also contributing to the flux of metals to seawater, with biogeochemical implications. Owing to the evolution of magmatic and tectonic processes associated with crustal formation at both fast and slow spreading ridges, chemical and physical conditions can change in space and time with corresponding changes in the solubility of Cu and Fe. Indeed, time series observations of hydrothermal vent fluids at EPR 9o N have provided unambiguous evidence of both diking and eruptive events with important implications for temperature and pressure changes affecting phase equilibria controls on mineral solubility. At the same time, recent advances in theoretical data have resulted in more robust thermodynamic models that can be used to calculate the effect of temperature and pressure, redox variability and dissolved chloride on metal mobility. However, fluid speciation calculations employing currently accepted Helgeson-Kirkham-Flowers (HKF) parameters for aqueous species result in Cu and Fe solubilities that differ significantly from constraints imposed by published experimental data and sampled MOR vent fluids. Consequently, new thermodynamic data is retrieved in this study from recent high P, T experimental data for Cu and Fe complexes and validated against new experiments to ensure accurate fluid speciation and trace metal solubility calculations. The addition of new experimental data to the thermodynamic data retrieval process strengthens predictions of geochemical interactions not only at the P and T of the experiments, but also over the entire range of applicability of the HKF model. For example, theoretical modeling of seawater salinity fluids (550 mmol/kg Cl) at 400 oC show

  10. Correlates of experimentation with smoking and current cigarette consumption among adolescents

    Directory of Open Access Journals (Sweden)

    Amanda Gimenes Bonilha

    2014-12-01

    Full Text Available OBJECTIVE: The aim of this study was to analyze social characteristics and stress as correlates of cigarette smoking in adolescence. The main intent was to identify elements that distinguish adolescents who had experimented with smoking and did not progress to regular smoking from those who became current smokers. METHODS: Students at 10 high schools in the city of Ribeirão Preto, Brazil, completed a questionnaire based on an instrument employed in a similar large-scale study. The students were classified as never-smokers or experimenters. The experimenters were subcategorized as having become current smokers or nonprogressors. Analyses were performed using adjusted logistic models. RESULTS: A total of 2,014 students (mean age, 16.2 ± 1.1 years; females, 53% completed the questionnaire. We categorized 1,283 students (63.7% as never-smokers, 244 (12.1% as current smokers, and 487 (24.2% as nonprogressors. We found that experimentation with smoking was associated with being held back a grade in school (OR = 1.80, alcohol intake (low/occasional, OR = 8.92; high/regular, OR = 2.64, illicit drug use (OR = 9.32, having a sibling or cousin who smokes (OR = 1.39, having a friend who smokes (OR = 2.08, and high levels of stress (in females only, OR = 1.32. Factors associated with an increased risk of transitioning from experimenter to current smoker were alcohol intake (low/occasional, OR = 3.28; high/regular, OR = 2.16, illicit drug use (OR = 3.61, and having a friend who smokes (OR = 7.20. CONCLUSIONS: Current smoking was associated with a profile of socioeconomic correlates different from that associated with experimentation only. Our data (showing that current smoking was associated with having a friend who smokes, alcohol intake, and illicit drug use suggest the need for comprehensive approaches to discourage substance use during adolescence.

  11. Experimental observations of stray current effects on steel fibres embedded in mortar

    DEFF Research Database (Denmark)

    Solgaard, A.O.S.; Carsana, M.; Geiker, M.R.;

    2013-01-01

    It is known that stray direct current can cause corrosive damage over time to bar reinforced concrete, but knowledge on the consequences to steel fibre reinforced concrete is limited. This paper presents analyses and corresponding results from an experimental program (parametric study) investigat...

  12. Experimental Results on Current-Driven Turbulence in Plasmas - a Survey

    NARCIS (Netherlands)

    Dekluiver, H.; Perepelkin, N. F.; Hirose, A.

    1991-01-01

    The experimental consequences of plasma turbulence driven by a current parallel to a magnetic field and concurrent anomalous plasma heating are reviewed, with an attempt to deduce universalities in key parameters such as the anomalous electrical conductivities observed in diverse devices. It has

  13. Constraint-based modeling of heterologous pathways: application and experimental demonstration for overproduction of fatty acids in Escherichia coli.

    Science.gov (United States)

    Ip, Kuhn; Donoghue, Neil; Kim, Min Kyung; Lun, Desmond S

    2014-10-01

    Constraint-based modeling has been shown, in many instances, to be useful for metabolic engineering by allowing the prediction of the metabolic phenotype resulting from genetic manipulations. But the basic premise of constraint-based modeling-that of applying constraints to preclude certain behaviors-only makes sense for certain genetic manipulations (such as knockouts and knockdowns). In particular, when genes (such as those associated with a heterologous pathway) are introduced under artificial control, it is unclear how to predict the correct behavior. In this paper, we introduce a modeling method that we call proportional flux forcing (PFF) to model artificially induced enzymatic genes. The model modifications introduced by PFF can be transformed into a set of simple mass balance constraints, which allows computational methods for strain optimization based on flux balance analysis (FBA) to be utilized. We applied PFF to the metabolic engineering of Escherichia coli (E. coli) for free fatty acid (FFA) production-a metabolic engineering problem that has attracted significant attention because FFAs are a precursor to liquid transportation fuels such as biodiesel and biogasoline. We show that PFF used in conjunction with FBA-based computational strain optimization methods can yield non-obvious genetic manipulation strategies that significantly increase FFA production in E. coli. The two mutant strains constructed and successfully tested in this work had peak fatty acid (FA) yields of 0.050 g FA/g carbon source (17.4% theoretical yield) and 0.035 g FA/g carbon source (12.3% theoretical yield) when they were grown using a mixed carbon source of glucose and casamino acids in a ratio of 2-to-1. These yields represent increases of 5.4- and 3.8-fold, respectively, over the baseline strain.

  14. EXPERIMENTAL INVESTIGATIONS ON DIFFUSION CHARACTERISTICS OF HIGH CONCENTRATION JETS IN ENVIRONMENTAL CURRENTS

    Institute of Scientific and Technical Information of China (English)

    张燕; 王道增; 樊靖郁

    2002-01-01

    By means of flow visualization and quantitative measurement, the diffusionpattern and concentration distribution characteristics of high concentration jets verticallydischarged into shallow moving waterbody were experimentally investigated in waterchannel. The interactions between the high concentration jets and environmental flowconditions were analysed, and the formulae of impinging point coordinate and transversespread angle are gained from data analysis. Experimental results indicate that the jets showcomplicated flow patterns and diffusion characteristics in near region, which are differentfrom common submerged jets, and spread downstream in the manner of density currents.

  15. Experimental Investigation of a Direct Methanol Fuel Cell with Hilbert Fractal Current Collectors

    Directory of Open Access Journals (Sweden)

    Jing-Yi Chang

    2014-01-01

    Full Text Available The Hilbert curve is a continuous type of fractal space-filling curve. This fractal curve visits every point in a square grid with a size of 2×2, 4×4, or any other power of two. This paper presents Hilbert fractal curve application to direct methanol fuel cell (DMFC current collectors. The current collectors are carved following first, second, and third order Hilbert fractal curves. These curves give the current collectors different free open ratios and opening perimeters. We conducted an experimental investigation into DMFC performance as a function of the free open ratio and opening perimeter on the bipolar plates. Nyquist plots of the bipolar plates are made and compared using electrochemical impedance spectroscopy (EIS experiments to understand the phenomena in depth. The results obtained in this paper could be a good reference for future current collector design.

  16. Experimental Research of Harmonic Spectrum of Currents at Traction Drive with PMSM

    Directory of Open Access Journals (Sweden)

    J. Novak

    2011-06-01

    Full Text Available The paper deals with the significant results of the experimental research of current harmonic spectrum of traction drive with permanent magnet synchronous motor. The experiments were done on a special workplace with a real traction drive for wheel vehicles. Current harmonic spectrum was analyzed by a specialized device on the base of central measuring station. The knowledge of current marked subharmonic components of stator winding is the most significant finding of experiments. The frequencies of these components are given by multiples of frequency of mechanical speeds. The subharmonic components also pass to input DC current of drive. This fact is important in particular from the point of view of legislative requirements to electromagnetic compatibility of drive with railway interlocking devices.

  17. Evaluating the osseointegration of nanostructured titanium implants in animal models: Current experimental methods and perspectives (Review).

    Science.gov (United States)

    Babuska, Vaclav; Moztarzadeh, Omid; Kubikova, Tereza; Moztarzadeh, Amin; Hrusak, Daniel; Tonar, Zbynek

    2016-09-15

    The aim of this paper is to review the experimental methods currently being used to evaluate the osseointegration of nanostructured titanium implants using animal models. The material modifications are linked to the biocompatibility of various types of oral implants, such as laser-treated, acid-etched, plasma-coated, and sand-blasted surface modifications. The types of implants are reviewed according to their implantation site (endoosseous, subperiosteal, and transosseous implants). The animal species and target bones used in experimental implantology are carefully compared in terms of the ratio of compact to spongy bone. The surgical technique in animal experiments is briefly described, and all phases of the histological evaluation of osseointegration are described in detail, including harvesting tissue samples, processing undemineralized ground sections, and qualitative and quantitative histological assessment of the bone-implant interface. The results of histological staining methods used in implantology are illustrated and compared. A standardized and reproducible technique for stereological quantification of bone-implant contact is proposed and demonstrated. In conclusion, histological evaluation of the experimental osseointegration of dental implants requires careful selection of the experimental animals, bones, and implantation sites. It is also advisable to use larger animal models and older animals with a slower growth rate rather than small or growing experimental animals. Bones with a similar ratio of compact to spongy bone, such as the human maxilla and mandible, are preferred. A number of practical recommendations for the experimental procedures, harvesting of samples, tissue processing, and quantitative histological evaluations are provided.

  18. Constraints on the Formation of Double Neutron Stars from the Observed Eccentricities and Current Limits on Merger Rates

    Science.gov (United States)

    Chruslinska, M.; Belczynski, K.; Bulik, T.; Gladysz, W.

    2017-03-01

    We employ population synthesis method to model the double neutron star (DNS) population and test various possibilities on natal kick velocities gained by neutron stars after their formation. We first choose natal kicks after standard core collapse supernovae (CCSN) from a Maxwellian distribution with velocity dispersion of σ = 265 km/s as proposed by Hobbs and then modify this distribution by changing σ toward smaller and larger kick values. We also take into account the possibility of NS formation through electron capture supernova. In this case we test two scenarios: zero natal kick or small natal kick, drawn from Maxwellian distribution with σ = 26.5 km/s. We calculate the present-day orbital parameters of binaries and compare the resulting eccentricities with those known for observed DNSs. As an additional test we calculate Galactic merger rates for our model populations and confront them with observational limits. We do not find any model unequivocally consistent with both observational constraints simultaneously. The models with low kicks after CCSN for binaries with the second NS forming through core collapse SN are marginally consistent with the observations. This means that either 14 observed DNSs are not representative of the intrinsic Galactic population, or that our modeling of DNS formation needs revision.

  19. Experimental manifestation of the breakpoint region in the current-voltage characteristics of intrinsic Josephson junctions

    Science.gov (United States)

    Irie, A.; Shukrinov, Yu. M.; Oya, G.

    2008-10-01

    The experimental evidence of the breakpoint on the current-voltage characteristics (IVCs) of the stacks of intrinsic Josephson junctions (IJJs) is presented. The influence of the capacitive coupling on the IVCs of Bi2Sr2CaCu2Oy IJJs has been investigated. At 4.2K, clear breakpoint region is observed on the branches in the IVCs. It is found that due to the coupling between junctions, the hysteresis observed on the IVC is small compared to that expected from the McCumber parameter. Measurements agree well with the results predicted by the capacitively coupled Josephson junction model including the diffusion current.

  20. High performance predictive current control of a three phase VSI: An experimental assessment

    Indian Academy of Sciences (India)

    Vikas Kumar; Prerna Gaur; A P Mittal

    2014-12-01

    Delay has a significant role to play in the implementation of the predictive current control scheme as large amount of calculations are involved. Compensating delay in the predictive current controller design can lead to an improved load current total harmonic distortion (THD) and also an increased switching frequency. Minimization of switching frequency while maintaining the lower value of load current THD requires multiple objective optimization which is achieved by optimizing a single objective function, constructed using weighting factors as a linear combination of individual objective function. The effect of weighting factor on the switching frequency minimization and the current tracking error with delay compensation for the two level voltage source inverter (VSI) are investigated in this paper. The outcomes of the predictive current control using an optimized weighting factor which is calculated using branch and bound algorithm with the delay compensation are compared with the PWM based current control scheme. The experimental tests are conducted on a 2.2 kW VSI to verify the simulation observations.

  1. Synergistic effect of combined transcranial direct current stimulation/constraint-induced movement therapy in children and young adults with hemiparesis: study protocol.

    Science.gov (United States)

    Gillick, Bernadette; Menk, Jeremiah; Mueller, Bryon; Meekins, Gregg; Krach, Linda E; Feyma, Timothy; Rudser, Kyle

    2015-11-12

    Perinatal stroke occurs in more than 1 in 2,500 live births and resultant congenital hemiparesis necessitates investigation into interventions which may improve long-term function and decreased burden of care beyond current therapies ( http://www.cdc.gov/ncbddd/cp/data.html ). Constraint-Induced Movement Therapy (CIMT) is recognized as an effective hemiparesis rehabilitation intervention. Transcranial direct current stimulation as an adjunct treatment to CIMT may potentiate neuroplastic responses and improve motor function. The methodology of a clinical trial in children designed as a placebo-controlled, serial -session, non-invasive brain stimulation trial incorporating CIMT is described here. The primary hypotheses are 1) that no serious adverse events will occur in children receiving non-invasive brain stimulation and 2) that children in the stimulation intervention group will show significant improvements in hand motor function compared to children in the placebo stimulation control group. A randomized, controlled, double-blinded clinical trial. Twenty children and/or young adults (ages 8-21) with congenital hemiparesis, will be enrolled. The intervention group will receive ten 2-hour sessions of transcranial direct current stimulation combined with constraint-induced movement therapy and the control group will receive sham stimulation with CIMT. The primary outcome measure is safety assessment of transcranial direct current stimulation by physician evaluation, vital sign monitoring and symptom reports. Additionally, hand function will be evaluated using the Assisting Hand Assessment, grip strength and assessment of goals using the Canadian Occupational Performance Measure. Neuroimaging will confirm diagnoses, corticospinal tract integrity and cortical activation. Motor cortical excitability will also be examined using transcranial magnetic stimulation techniques. Combining non-invasive brain stimulation and CIMT interventions has the potential to improve motor

  2. Computational and experimental studies of laser cutting of the current collectors for lithium-ion batteries

    Science.gov (United States)

    Lee, Dongkyoung; Patwa, Rahul; Herfurth, Hans; Mazumder, Jyotirmoy

    2012-07-01

    Sizing electrodes is an important step during Lithium-ion battery manufacturing processes since poor cut edge affects battery performance significantly and sometime leads to fire hazard. Mechanical cutting could result in a poor cut quality with defects. The cutting quality can be improved by using a laser, due to its high energy concentration, fast processing time, small heat-affected zone, and high precision. The cutting quality is highly influenced by operating parameters such as laser power and scanning speed. Thus, we studied a numerical simulation to provide a guideline for achieving clear edge quality. In order to simulate electrodes laser cutting for Lithium-Ion batteries, understanding the behavior of current collectors is crucial. This study focuses on current collectors, such as pure copper and aluminium. Numerical studies utilized a 3D self-consistent mathematical model for laser-material interaction. Observations of penetration time, depth, and threshold during laser cutting processes of current collectors are described. The model is validated experimentally by cutting current collectors and single side-coated electrodes with a single mode fiber laser. The copper laser cutting is laser intensity and interaction time dependent process. The aluminium laser cutting depends more on laser intensity than the interaction time. Numerical and experimental results show good agreement.

  3. Principle and experimental investigation of current-driven negative-inductance superconducting quantum interference device

    Science.gov (United States)

    Li, Hao; Liu, Jianshe; Zhang, Yingshan; Cai, Han; Li, Gang; Liu, Qichun; Han, Siyuan; Chen, Wei

    2017-03-01

    A negative-inductance superconducting quantum interference device (nSQUID) is an adiabatic superconducting logic device with high energy efficiency, and therefore a promising building block for large-scale low-power superconducting computing. However, the principle of the nSQUID is not that straightforward and an nSQUID driven by voltage is vulnerable to common mode noise. We investigate a single nSQUID driven by current instead of voltage, and clarify the principle of the adiabatic transition of the current-driven nSQUID between different states. The basic logic operations of the current-driven nSQUID with proper parameters are simulated by WRspice. The corresponding circuit is fabricated with a 100 A cm‑2 Nb-based lift-off process, and the experimental results at low temperature confirm the basic logic operations as a gated buffer.

  4. Experimental study of the velocity of density currents in convergent and divergent channels

    Institute of Scientific and Technical Information of China (English)

    Hasan Torabi POUDEH; Samad EMAMGHOLIZADEH; Manoocher Fathi-MOGHADAM

    2014-01-01

    The head velocity of the density current in the convergent and divergent channel is a key parameter for evaluating the extent to which suspended material travels, and for determining the type and distribution of sediment in the water body. This study experimentally evaluated the effects of the reach degree of convergence and divergence on the head velocity of the density current. Experiments were conducted in the flume with 6.0 m long, 0.72 m width and 0.6 m height. The head velocity was measured at three convergent degrees (-8o;-12o;-26o), at three divergent degrees (8o; 12o; 26o) and two slopes (0.009, 0.016) for various discharges. The measured head velocity of the density current is compared with the head velocity of the density current in the constant cross section channel. Based on non-dimensional and statistical analysis, relations as linear multiple regression are offered for predicting head velocity of the density current in the convergent, divergent and constant cross section channel. Also the results of this research show that for the same slope and discharge, the head velocity of the density current in the convergent and divergent channel are greater and less than the head velocity of the constant cross section, respectively.

  5. Integral Constraints and MHD Stability

    Science.gov (United States)

    Jensen, T. H.

    2003-10-01

    Determining stability of a plasma in MHD equilibrium, energetically isolated by a conducting wall, requires an assumption on what governs the dynamics of the plasma. One example is the assumption that the plasma obeys ideal MHD, leading to the well known ``δ W" criteria [I. Bernstein, et al., Proc. Roy. Soc. London A244, 17 (1958)]. A radically different approach was used by Taylor [J.B. Taylor, Rev. Mod. Phys. 58, 741 (1986)] in assuming that the dynamics of the plasma is restricted only by the requirement that helicity, an integral constant associated with the plasma, is conserved. The relevancy of Taylor's assumption is supported by the agreement between resulting theoretical results and experimental observations. Another integral constraint involves the canonical angular momentum of the plasma particles. One consequence of using this constraint is that tokamak plasmas have no poloidal current in agreement with some current hole tokamak observations [T.H. Jensen, Phys. Lett. A 305, 183 (2002)].

  6. Geotectonic Elements, Stuctural Constraints and Current Problems for a Kinematic Reconstruction of the Caribbean Plate Margins during the Cretaceous.

    Science.gov (United States)

    Giunta, G.

    2001-12-01

    blocks; (2) the sinking direction of the previously subducted oceanic slabs; (3) the locations of and relationships between the intraoceanic and sub-continental subduction zones. Taking this points into account and on the basis of the new geological constraints, some alternative tectonic models can be elaborated, each of which needs kinematic releases (strike-slip faults) allowing either the simultaneous activation of intraoceanic and sub-continental collisions, or the progressive insertion by tectonic erosion of the rifted continental portions in the subduction complexes. In a whole transpressional regime the different subduction zones can be inferred to dip either eastward with a later flip westward below the oceanic plateau, or continuously westward; this last case is a better fit for the Northern margin than the Southern margin of the Caribbean plate, where a much more complicated kinematic mechanism should be envisaged. * Researches carried-out in the framework of the IGCP 433 "Caribbean Plate Tectonics".

  7. A Critical Examination of Current On-Orbit Satellite Collision Risk Analysis Under Constraints of Public Data

    Science.gov (United States)

    Whitworth, Brandon; Moon, Mark; Pace, William; Baker, Robert

    2010-09-01

    The collision of Cosmos 2251 and Iridium 33 on 10 February 2009, made real the dangers of space operations without accurate situational awareness. A critical examination of the state of the art in collision risk assessment for on-orbit assets quickly reveals that it is inadequate to have provided satellite operators the opportunity to prevent the Cosmos-Iridium collision. Satellite operators need reliable information in a timely manner in order to take appropriate action. The shortfalls of publicly available orbit information place all spacecraft and missions at risk. The accuracy limitations of the General Perturbations(GP) catalog and orbit model(SGP-4) limit the effectiveness of current open source efforts. Beyond the accuracy limits, the relatively low frequency of updates for debris included in the catalog increases the uncertainty in time-space for inactive space objects such as Cosmos 2251. The current state of the art collision risk assessment includes advanced techniques such as expanding the GP model with covariance information which will allow uncertainty in the model to be accounted for in the on-orbit risk calculations. Covariance information can be estimated from consecutively published element sets for the same orbital object. A challenge to covariance estimation is that maneuvers or long periods of time between updates can skew the computed data. Once reliable covariance information is known and an efficient algorithm can be applied to find all of the close approaches between all cataloged objects then it is possible to estimate the collision risk for each close encounter with the tri-variate normal distribution. Unknown covariance will need to be handled in an appropriate way for a complete solution. Covariance information alone cannot solve the problem due to the relatively slow rate of update for all objects by the Space Surveillance Network(SSN) and there is no centralized source for planned and executed orbit changes for powered spacecraft. The

  8. EXPERIMENTAL STUDY ON BED-LOAD SEDIMENT TRANSPORT IN IRREGULAR WAVE-CURRENT COEXISTENT FIELD

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In order to evaluate bed-load sediment transport in an irregular wave-current coexistent field, a series of experiments were completed in laboratory with an irregularly oscillating tray, which was specially designed to simulate the irregular wave-current coexistent field. Experimental results are presented on the initial motion of sediment and the rates of transport over flat horizontal bed. Testing conditions included three interaction angles, 0°, 45°, 90° and six kinds of grain sizes. Four kinds (0.2mm, 0.46mm, 0.85mm and 1.3mm) were used for the tests of initial motion, while the other two kinds (0.38mm and 1.1mm) for the tests of transport rate. Comparisons between experimental results of initial motion and modified Shields curve indicate that the Shields curve is still valid for the case of irregular wave-current coexistent field. Analysis of flow regime shows that initial conditions fall within smooth-turbulent transitional region. The results of transport rate show us that net sediment transport rate can be expressed approximately as the function of the maximum bottom shear stress and mean shear stress. A dimensionless formula is proposed on the basis of mechanism "Waves erode sediments, tides transport sediments".

  9. Numerical simulation and experimental validation of a direct current air corona discharge under atmospheric pressure

    Institute of Scientific and Technical Information of China (English)

    Liu Xing-Hua; He Wei; Yang Fan; Wang Hong-Yu; Liao Rui-Jin; Xiao Han-Guang

    2012-01-01

    Air corona discharge is one of the critical problems associated with high-voltage equipment.Investigating the corona mechanism plays a key role in enhancing the electrical insulation performance.An improved self-consistent multi-component two-dimensional plasma hybrid model is presented for the simulation of a direct current atmospheric pressure corona discharge in air.The model is based on plasma hydrodynamic and chemical models,and includes 12 species and 26 reactions.In addition,the photoionization effect is introduced into the model.The simulation on a bar-plate electrode configuration with an inter-electrode gap of 5.0 mm is carried out.The discharge voltage-current characteristics and the current density distribution predicted by the hybrid model agree with the experimental measurements.In addition,the dynamics of volume charged species generation,discharge current waveform,current density distribution at an electrode,charge density,electron temperature,and electric field variations are investigated in detail based on the model.The results indicate that the model can contribute valuable insights into the physics of an air plasma discharge.

  10. Experimental manifestation of the breakpoint region in the current-voltage characteristics of intrinsic Josephson junctions

    OpenAIRE

    Irie, A.; Shukrinov, Yu M.; Oya, G.

    2008-01-01

    The experimental evidence of the breakpoint on the current-voltage characteristics (IVCs) of the stacks of intrinsic Josephson junctions (IJJs) is presented. The influence of the capacitive coupling on the IVCs of Bi$_2$Sr$_2$CaCu$_2$O$_y$ IJJs has been investigated. At 4.2 K, clear breakpoint region is observed on the branches in the IVCs. It is found that the hysteresis observed on the IVC is suppressed due to the coupling compared with that expected from the McCumber parameter. Measurement...

  11. Experimental Investigations on PV Powered SVM-DTC Induction Motor without AC Phase Current Sensors

    Directory of Open Access Journals (Sweden)

    T. Muthamizhan

    2014-05-01

    Full Text Available The paper presents a low-cost, phase-current reconstruction algorithm for space vector modulated direct torque controlled induction motor using the information obtained from only one shunt resistor which is in series with low side switches in a conventional three-phase inverter. The aim is to develop a low-cost high - performance induction motor drive. It uses the dc-link voltage and dc current to reconstruct the stator currents needed to estimate the motor flux and the electromagnetic torque. Photovoltaic arrays convert solar power to dc electric power; uses chopper and dc-ac inverter to fed three phase Induction Motor. The chopper used here is current fed full bridge boost dc-dc converter, which is preferred and extensively used in high voltage applications and advantageous over voltage fed converters. The inverter switches are controlled by PWM techniques obtained from SVM-DTC of IM. The experimental investigations are given to prove the ability of the proposed scheme of reproducing the performances of a SVM- DTC IM drive.

  12. Safety and efficacy of transcranial direct current stimulation in acute experimental ischemic stroke.

    Science.gov (United States)

    Peruzzotti-Jametti, Luca; Cambiaghi, Marco; Bacigaluppi, Marco; Gallizioli, Mattia; Gaude, Edoardo; Mari, Silvia; Sandrone, Stefano; Cursi, Marco; Teneud, Luis; Comi, Giancarlo; Musco, Giovanna; Martino, Gianvito; Leocani, Letizia

    2013-11-01

    Transcranial direct current stimulation is emerging as a promising tool for the treatment of several neurological conditions, including cerebral ischemia. The therapeutic role of this noninvasive treatment is, however, limited to chronic phases of stroke. We thus ought to investigate whether different stimulation protocols could also be beneficial in the acute phase of experimental brain ischemia. The influence of both cathodal and anodal transcranial direct current stimulation in modifying brain metabolism of healthy mice was first tested by nuclear magnetic resonance spectroscopy. Then, mice undergoing transient proximal middle cerebral artery occlusion were randomized and treated acutely with anodal, cathodal, or sham transcranial direct current stimulation. Brain metabolism, functional outcomes, and ischemic lesion volume, as well as the inflammatory reaction and blood brain barrier functionality, were analyzed. Cathodal stimulation was able, if applied in the acute phase of stroke, to preserve cortical neurons from the ischemic damage, to reduce inflammation, and to promote a better clinical recovery compared with sham and anodal treatments. This finding was attributable to the significant decrease of cortical glutamate, as indicated by nuclear magnetic resonance spectroscopy. Conversely, anodal stimulation induced an increase in the postischemic lesion volume and augmented blood brain barrier derangement. Our data indicate that transcranial direct current stimulation exerts a measurable neuroprotective effect in the acute phase of stroke. However, its timing and polarity should be carefully identified on the base of the pathophysiological context to avoid potential harmful side effects.

  13. Experimental and theoretical investigations on the singularity of the intensity factor of the current in high temperature superconductors

    Science.gov (United States)

    Zhang, Xingyi; Huang, Yi; Zhou, Jun; Zhou, Youhe

    2013-08-01

    This paper presents experimental and analytical investigations into the distribution of current around a through-edge crack located in an infinitely long cylindrical high temperature superconductor (HTS) on the basis of the Bean model. Current distributions around the crack in the HTS without deformation are obtained by a simple conformal mapping. It is shown that the current is singular at the tip of the crack. An intensity factor of the current is introduced to characterize the singularity, the order of which is equal to -1. Additionally, an experimental verification according to the trapped field distributions around the crack is carried out, and the experimental results show little difference with the theoretical analysis.

  14. Experimental Determination of DT Yield in High Current DD Dense Plasma Focii

    Energy Technology Data Exchange (ETDEWEB)

    Lowe, D. R. [National Security Technologies, LLC; Hagen, E. C. [National Security Technologies, LLC; Meehan, B. T. [National Security Technologies, LLC; Springs, R. K. [University of Nevada, Las Vegas; O' Brien, R. J. [University of Nevada, Las Vegas

    2013-06-18

    Dense Plasma Focii (DPF), which utilize deuterium gas to produce 2.45 MeV neutrons, may in fact also produce DT fusion neutrons at 14.1 MeV due to the triton production in the DD reaction. If beam-target fusion is the primary producer of fusion neutrons in DPFs, it is possible that ejected tritons from the first pinch will interact with the second pinch, and so forth. The 2 MJ DPF at National Security Technologies’ Losee Road Facility is able to, and has produced, over 1E12 DD neutrons per pulse, allowing an accurate measurement of the DT/DD ratio. The DT/DD ratio was experimentally verified by using the (n,2n) reaction in a large piece of praseodymium metal, which has a threshold reaction of 8 MeV, and is widely used as a DT yield measurement system1. The DT/DD ratio was experimentally determined for over 100 shots, and then compared to independent variables such as tube pressure, number of pinches per shot, total current, pinch current and charge voltage.

  15. Experimental demonstration of a new radiation mechanism: emission by an oscillating, accelerated, superluminal polarization current

    CERN Document Server

    Ardavan, A; Ardavan, H; Fopma, J; Halliday, D; Hayes, W

    2004-01-01

    We describe the experimental implementation of a superluminal ({\\it i.e.} faster than light {\\it in vacuo}) polarization current distribution that both oscillates and undergoes centripetal acceleration. Theoretical treatments lead one to expect that the radiation emitted from each volume element of such a polarization current will comprise a \\v{C}erenkov-like envelope with two sheets that meet along a cusp. The emission from the experimental machine is in good agreement with these expectations, the combined effect of the volume elements leading to tightly-defined beams of a well-defined geometry, determined by the source speed and trajectory. In addition, over a restricted range of angles, we detect the presence of cusps in the emitted radiation. These are due to the detection over a short time period (in the laboratory frame) of radiation emitted over a considerably longer period of source time. Consequently, the intensity of the radiation at these angles was observed to decline more slowly with increasing d...

  16. Phreatic activity in the Valley of Desolation, Dominica (Lesser Antilles) - constraints from field investigations and experimental volcanology

    Science.gov (United States)

    Mayer, Klaus; Scheu, Bettina; Montanaro, Cristian; Yilmaz, Tim; Aßbichler, Donja; Gilg, H. Albert; Dingwell, Donald B.

    2016-04-01

    Dominica has one of the highest concentrations of potentially active volcanoes worldwide, flanked by abundant surficial geothermal manifestations: The Boiling Lake - Valley of Desolation area represents one of the most vigorous ones, hosting hot springs, mud pools, fumaroles, and steam vents. Intense alteration, together with predominantly phreatic explosive features of varying scales, characterize the whole area. The last historic eruptions in Dominica occurred at the Valley of Desolation. Phreatic eruptions are also the most likely type of volcanic activity to occur in the near future at Dominica in general and the Valley of Desolation in particular. Phreatic eruptions are up to date largely unpredictable in time and magnitude, strongly asking for constraints of eruptive conditions as well as trigger mechanisms. We conducted sampling and field mapping, together with the determination of in situ physical (density, humidity, permeability) and mechanical (strength, stiffness) properties to characterize the main active surficial area which possesses a high probability for a phreatic event. Rapid decompression experiments performed on selected samples from this area give insight into the fragmentation and ejection behavior of steam driven eruptions. These experiments were flanked by chemical analyses and laboratory measurements as porosity and granulometry. The results indicate that advanced argillic alteration in the proximity of degassing vents significantly changes the rock properties, which in turn play a crucial role for the degassing of hydrothermal systems. High-temperature acidic fluids lead to an intense alteration of the host rocks, and thereby cause the formation of a kaolinite-rich, low permeable layer above the vent. In addition, alteration enhances slope instabilities causing landslides which may cover and clog the outgassing vents. Such processes increase the likelihood of the site experiencing a pressurization, which may result in a steam

  17. Clinical and experimental studies on polyherbal formulations for diabetes:current status and future prospective

    Institute of Scientific and Technical Information of China (English)

    Ahmad Ghorbani

    2014-01-01

    Diabetes is a leading cause of morbidity and mortality in the world. There is currently an active search for antidiabetic drugs with greater effectiveness with fewer and less adverse side effects. Although numerous individual herbs have been experimentally or clinically reported to possess antidiabetic effects, considerably less research has been conducted on polyherbal compounds. It is believed that herbal compounds containing multiple plant products have synergistic antidiabetic effects and could enhance the desired actions. Several polyherbal formulations have been studied as therapeutic agents in diabetes management. To describe the current state of research on polyherbal compounds in the treatment of diabetes, an extensive review of literature was undertaken on several major databases. This paper presents what is known about the efifcacy of these polyherbal formulations and compare their antidiabetic effects with those of current oral hypoglycemic drugs as reference. The percent decrease in blood glucose, lipids and other biochemical parameters achieved by each product in diabetic animals and patients is reported. Also, the possible mechanisms responsible for hypoglycemic action of polyherbal formulations are discussed.

  18. Experimental evidence of bulk chemistry constraint on SiO2 solubility in clinopyroxene at high-pressure conditions

    Science.gov (United States)

    Kawasaki, Toshisuke; Osanai, Yasuhito

    2015-06-01

    We have experimentally confirmed that the solubility of SiO2 in clinopyroxene at ultrahigh-pressure metamorphic conditions is buffered by coesite and kyanite. The present findings were derived from high-pressure experiments on metapelite glass, powdered andesite and eclogite glass under anhydrous conditions. The metapelite glass and powdered andesite were recrystallised in boron nitride capsules at 8 GPa and 1100-1500 °C. The eclogite glass was heated in an AuPd capsule, both ends of which were welded, at 3 GPa and 1000 °C. Clinopyroxene nucleated from metapelite glass, the bulk composition of which is saturated in both SiO2 and Al2SiO5 components plotting within the Jd (Na,K)(Al,Cr)(Si,Ti)2O6-Qtz (Si,Ti)O2-Grt M3(Al,Cr)2(Si,Ti)3O12-Als (Al,Cr)2(Si,Ti)O5 tetrahedron (M = Fe, Mn, Mg, Ni, Zn, Ca), coexists with garnet, coesite and kyanite. The average excess silica content of the clinopyroxene ranges from 23.4 to 35.4 mol%. In contrast, an andesite experiment saturated in SiO2 but undersaturated in Al2SiO5 within the Jd-Qtz-Aug M(Si,Ti)O3-Grt tetrahedron produced clinopyroxene, garnet and coesite but no kyanite. The average excess silica in the clinopyroxene was 9.7-15.5 mol%, which is comparable to previous experimental data. Experiment on the eclogite glass with similar composition to andesite yielded clinopyroxene, garnet and coesite. An average excess silica content in clinopyroxene counts 6.4 mol%, which is much lower than that obtained from the andesite. The SiO2 content of clinopyroxene coexisting with garnet, coesite and kyanite is much higher than that of clinopyroxene coexisting with garnet and coesite without kyanite. Although the temperature dependence is unclear, the SiO2 solubility increases with pressure and Fe/(Fe+Mg). Clinopyroxene forms the solid solution series Jd-Es □0.5M0.5Al(Si,Ti)2O6 and Aug-Es, rather than Jd-Ts MAl2(Si,Ti)O6 and Es-Ts joins. Our experimental data suggest the probable existence of octahedral Si which may accompany the M2

  19. Experimental constraints on the differentiation process and pre-eruptive conditions in the magmatic system of Phlegraean Fields (Naples, Italy)

    Science.gov (United States)

    Fabbrizio, Alessandro; Carroll, Michael R.

    2008-03-01

    Phase relations of two samples of the Breccia Museo Eruption (BME), BME is an explosive event that took place (about 20 ky ago) during the caldera-forming phase of the Ignimbrite Campana eruption, have been determined experimentally as a function of temperature (700 to 885 °C), pressure (50 to 200 MPa) and water content of the melt. The crystallization experiments were carried out at fO 2 = NNO + 1 log unit. Melt water content ranged from 3.4 to 8 wt.% (H 2O saturation). The synthetic products are compared to the natural phases to constrain the pre-eruptive conditions of trachytic magma in the presence of an H 2O-rich fluid. The major phases occurring in the BME have been reproduced. The stability of biotite is favoured at pressures higher than 135 MPa. Phase equilibria at 200 MPa reproduce the phase assemblage of the magma only at temperatures below 775 °C. Phase abundances and melt fractions indicate that the eruption tapped a magma body that was at a temperature of 780 °C and a pressure in the range 200-140 MPa. The observed major element variations are fully consistent with a fractional crystallization of a sanidine-dominated assemblage starting from the least differentiated trachytes. The compositions of the experimental products are compatible with the progressive tapping of a shallow magma chamber that was chemically zoned. These results suggest that after an early eruptive phase during which the upper, most differentiated level of the magma chamber was tapped, the sudden collapse of the roof of the reservoir triggered drainage of the less evolved remaining magma.

  20. Experimental constraints on melting temperatures in the MgO-SiO2 system at lower mantle pressures

    Science.gov (United States)

    Baron, Marzena A.; Lord, Oliver T.; Myhill, Robert; Thomson, Andrew R.; Wang, Weiwei; Trønnes, Reidar G.; Walter, Michael J.

    2017-08-01

    Eutectic melting curves in the system MgO-SiO2 have been experimentally determined at lower mantle pressures using laser-heated diamond anvil cell (LH-DAC) techniques. We investigated eutectic melting of bridgmanite plus periclase in the MgO-MgSiO3 binary, and melting of bridgmanite plus stishovite in the MgSiO3-SiO2 binary, as analogues for natural peridotite and basalt, respectively. The melting curve of model basalt occurs at lower temperatures, has a shallower dT / dP slope and slightly less curvature than the model peridotitic melting curve. Overall, melting temperatures detected in this study are in good agreement with previous experiments and ab initio simulations at ∼25 GPa (Liebske and Frost, 2012; de Koker et al., 2013). However, at higher pressures the measured eutectic melting curves are systematically lower in temperature than curves extrapolated on the basis of thermodynamic modelling of low-pressure experimental data, and those calculated from atomistic simulations. We find that our data are inconsistent with previously computed melting temperatures and melt thermodynamic properties of the SiO2 endmember, and indicate a maximum in short-range ordering in MgO-SiO2 melts close to Mg2SiO4 composition. The curvature of the model peridotite eutectic relative to an MgSiO3 melt adiabat indicates that crystallization in a global magma ocean would begin at ∼100 GPa rather than at the bottom of the mantle, allowing for an early basal melt layer. The model peridotite melting curve lies ∼ 500 K above the mantle geotherm at the core-mantle boundary, indicating that it will not be molten unless the addition of other components reduces the solidus sufficiently. The model basalt melting curve intersects the geotherm at the base of the mantle, and partial melting of subducted oceanic crust is expected.

  1. Experimental Investigation and Modelling for the Optimisation of Conduction Cooled HTS Hybrid Current Leads for SMES

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    It′s important that HTS tapes have lower thermal conductivity and higher transversal resistivity in order to reduce the heat leaks conducted along the tapes and AC losses in the high temperature superconducting system conduction-cooled by GM coolers. This paper presents an experimental investigation into the effects of pure Ag and AgAu alloys sheath materials on the properties of Bi(2223) multifilamentary tapes and the optimisation of conduction-cooled hybrid current leads made from copper and Bi(2223)/Ag or Bi(2223)/AgAu tapes. The thermal conductivity of the tapes were measured by cryogenic steady heat flux method and the resistance was measured by using standard DC four-probe method at low temperature. The results showed that the reduction of thermal conductivity by the addition of Au into the sheath material of Bi(2223) tapes was 650%, 750% and 850% lower than that of pure Ag sheathed Bi(2223) tapes and the increase of resistivity was 4.9, 10 and 19.4 times higher than that of pure Ag for the addition of 2.20%, 5.70% and 10.70%Au(atom ratio) respectively. And the study also attempts to optimise thermodynamically the conduction-cooled hybrid current lead by using a developed model, which took the irreversibility of commercial GM coolers, the contact resistance and thermal conductance into account. Predictions from the model showed that AgAu alloys were suitable candidate materials to replace Ag as sheath material of Bi(2223) tapes applied in HTS current leads. In addition, Bi(2223)/AgAu was a suitable material to be applied as the HTS section of hybrid current leads in conduction-cooled superconducting electric systems.

  2. Experimental Study on Vortex-Induced Vibrations of Submarine Pipeline near Seabed Boundary in Ocean Currents

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Unlike most previous studies on vortex-induced vibrations of a cylinder far from a boundary, this paper focuses on the influences of close proximity of a submarine pipeline to a rigid seabed boundary upon the dynamic responses of the pipeline in ocean currents. The effects of gap-to-diameter ratio and those of the stability parameter on the amplitude and frequency responses of a pipeline are investigated experimentally with a novel hydro-elastic facility. A comparison is made between the present experimental results of the amplitude and frequency responses for the pipes with seabed boundary effects and those for wall-free cylinders given by Govardhan and Williamson (2000) and Anand (1985). The comparison shows that the close proximity of a pipeline to seabed has much influence on the vortex-induced vibrations of the pipeline. Both the width of the lock-in ranges in terms of Vr and the dimensionless amplitude ratio Amax/D become larger with the decrease of the gap-to-diameter ratio e/D. Moreover, the vibration of the pipeline becomes easier to occur and its amplitude response becomes more intensive with the decrease of the stability parameter, while the pipeline frequency responses are affected slightly by the stability parameter.

  3. Experimental pain processing in individuals with cognitive impairment: current state of the science.

    Science.gov (United States)

    Defrin, Ruth; Amanzio, Martina; de Tommaso, Marina; Dimova, Violeta; Filipovic, Sasa; Finn, David P; Gimenez-Llort, Lydia; Invitto, Sara; Jensen-Dahm, Christina; Lautenbacher, Stefan; Oosterman, Joukje M; Petrini, Laura; Pick, Chaim G; Pickering, Gisele; Vase, Lene; Kunz, Miriam

    2015-08-01

    Cognitive impairment (CI) can develop during the course of ageing and is a feature of many neurological and neurodegenerative diseases. Many individuals with CI have substantial, sustained, and complex health care needs, which frequently include pain. However, individuals with CI can have difficulty communicating the features of their pain to others, which in turn presents a significant challenge for effective diagnosis and treatment of their pain. Herein, we review the literature on responsivity of individuals with CI to experimental pain stimuli. We discuss pain responding across a large number of neurological and neurodegenerative disorders in which CI is typically present. Overall, the existing data suggest that pain processing is altered in most individuals with CI compared with cognitively intact matched controls. The precise nature of these alterations varies with the type of CI (or associated clinical condition) and may also depend on the type of pain stimulation used and the type of pain responses assessed. Nevertheless, it is clear that regardless of the etiology of CI, patients do feel noxious stimuli, with more evidence for hypersensitivity than hyposensitivity to these stimuli compared with cognitively unimpaired individuals. Our current understanding of the neurobiological mechanisms underpinning these alterations is limited but may be enhanced through the use of animal models of CI, which also exhibit alterations in nociceptive responding. Further research using additional behavioural indices of pain is warranted. Increased understanding of altered experimental pain processing in CI will facilitate the development of improved diagnostic and therapeutic approaches for pain in individuals with CI.

  4. Comprehensive Experimental Performance Analysis of DSR, AODV and DSDV Routing Protocol for Different Metrics Values with Predefined Constraints

    Directory of Open Access Journals (Sweden)

    Zafar Mehmood

    2014-06-01

    Full Text Available A Mobile Adhoc Network is a multi-hop self-configuring network without any fixed infrastructure. Due to mobility of nodes, dynamic topology and highly dynamic environment, designing and implementing stable routing in Mobile Ad-hoc Networking is a major challenge and a critical issue. This paper analyses the performance analysis of on demand routing protocol, Dynamic Source Routing (DSR, Adhoc on Demand Distance Vector Routing (AODV and table driven protocol, Destination-Sequenced Distance Vectoring (DSDV using a network simulator NS2. Different types of test scenario have designed with fixed number of nodes but varying mobility. Different performance metric values like, throughput, delay, normalized network load, end to end delay, dropped packets, packets delivery ratio have been observed. The experimental results have been analysed and recommendation based on the obtained results has been proposed about the significance of each protocol in different scenarios and situations. The simulation results show that both protocols are good in performance in their own categories. We believe that findings of this paper will help the researcher to find the best protocol under predefined condition with varied mobility. We believe that this research will help the researcher to identify and further investigate any particular metrics value of AODV, DSR and DSDV.

  5. Some experimental constraints for spectral parameters used in the Warner and McIntyre gravity wave parameterization scheme

    Directory of Open Access Journals (Sweden)

    M. Ern

    2006-06-01

    Full Text Available In order to incorporate the effect of gravity waves (GWs on the atmospheric circulation most global circulation models (GCMs employ gravity wave parameterization schemes. To date, GW parameterization schemes in GCMs are used without experimental validation of the set of global parameters assumed for the GW launch spectrum. This paper focuses on the Warner and McIntyre GW parameterization scheme. Ranges of parameters compatible with absolute values of gravity wave momentum flux (GW-MF derived from CRISTA-1 and CRISTA-2 satellite measurements are deduced for several of the parameters and the limitations of both model and measurements are discussed. The findings presented in this paper show that the initial guess of spectral parameters provided by Warner and McIntyre (2001 are some kind of compromise with respect to agreement of absolute values and agreement of the horizontal structures found in both measurements and model results. Better agreement can be achieved by using a vertical wavenumber launch spectrum with a wider saturated spectral range and reduced spectral power in the unsaturated part. Still, even global features of the measurements remain unmatched, and it is inevitable to provide a globally varying source distribution in future.

  6. Some experimental constraints for spectral parameters used in the Warner and McIntyre gravity wave parameterization scheme

    Directory of Open Access Journals (Sweden)

    M. Ern

    2006-01-01

    Full Text Available In order to incorporate the effect of gravity waves (GWs on the atmospheric circulation most global circulation models (GCMs employ gravity wave parameterization schemes. To date, GW parameterization schemes in GCMs are used without experimental validation of the set of global parameters assumed for the GW launch spectrum. This paper focuses on the Warner and McIntyre GW parameterization scheme. Ranges of parameters compatible with absolute values of gravity wave momentum flux (GW-MF derived from CRISTA-1 and CRISTA-2 satellite measurements are deduced for several of the parameters and the limitations of both model and measurements are discussed. The findings presented in this paper show that the initial guess of spectral parameters provided by by Warner and McIntyre (2001 are some kind of compromise with respect to agreement of absolute values and agreement of the horizontal structures found in both measurements and model results. Better agreement can be achieved by using a vertical wavenumber launch spectrum with a wider saturated spectral range and reduced spectral power in the unsaturated part. However, even with this optimized set of global launch parameters not all features of the measurements are matched. This indicates that for further improvement spatial and seasonal variations of the launch parameters should be included in GW parameterization schemes.

  7. Experimental determination of two-dimensional critical current density distribution in YBCO coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Amemiya, Naoyuki; Shinkai, Yoshichika [Faculty of Engineering, Yokohama National University, Tokiwadai, Hodogaya, Yokohama (Japan); Iijima, Yasuhiro; Kakimoto, Kazuomi; Takeda, Kaoru [Materials Research Laboratory, Fujikura Ltd., Kiba, Koto, Tokyo (Japan)

    2001-08-01

    The critical current density (J{sub c}) distribution in YBCO coated conductors is attracting interest from the viewpoint of its influence on their AC loss characteristics as well as from material science and process engineering. A two-dimensional J{sub c} distribution in a YBCO coated conductor made by the IBAD (ion-beam assisted deposition) and the PLD (pulse-laser deposition) method can be determined by the magnetic-knife method with spatial resolutions of 0.2 mm lateral and 10 mm longitudinal directions, respectively. In an up-to-date 80A-class YBCO coated conductor, the J{sub c} is relatively uniform in the central part and reaches mbox{l_brace}7$x$10{sup 9} A m{sup -2}, {r_brace} while the J{sub c} fluctuates spatially in the central part of a tape fabricated earlier and with less critical current. Near the edges of the tapes, the J{sub c} is higher or lower than in the central part and the experimentally determined J{sub c} distributions are far from uniform. This suggests that a presumption of a uniform J{sub c} for AC loss estimations is not always reasonable and can lead to a large error in the estimated AC losses. (author)

  8. Experimental and numerical assessment of low-frequency current distributions from UMTS and GSM mobile phones.

    Science.gov (United States)

    Gosselin, Marie-Christine; Kühn, Sven; Kuster, Niels

    2013-12-07

    The evaluation of the exposure from mobile communication devices requires consideration of electromagnetic fields (EMFs) over a broad frequency range from dc to GHz. Mobile phones in operation have prominent spectral components in the low-frequency (LF) and radio-frequency (RF) ranges. While the exposure to RF fields from mobile phones has been comprehensively assessed in the past, the LF fields have received much less attention. In this study, LF fields from mobile phones are assessed experimentally and numerically for the global system for mobile (GSM) and universal mobile telecommunications system (UMTS) communication systems and conclusions about the global (LF and RF) EMF exposure from both systems are drawn. From the measurements of the time-domain magnetic fields, it was found that the contribution from the audio signal at a normal speech level, i.e., -16 dBm0, is the same order of magnitude as the fields induced by the current bursts generated from the implementation of the GSM communication system at maximum RF output level. The B-field induced by currents in phones using the UMTS is two orders of magnitude lower than that induced by GSM. Knowing that the RF exposure from the UMTS is also two orders of magnitude lower than from GSM, it is now possible to state that there is an overall reduction of the exposure from this communication system.

  9. Experimental diabetes induced by alloxan and streptozotocin: The current state of the art.

    Science.gov (United States)

    Radenković, Miroslav; Stojanović, Marko; Prostran, Milica

    2016-01-01

    Diabetes mellitus is a chronic metabolic disorder with a high prevalence worldwide. Animal models of diabetes represent an important tool in diabetes investigation that helps us to avoid unnecessary and ethically challenging studies in human subjects, as well as to obtain a comprehensive scientific viewpoint of this disease. Although there are several methods through which diabetes can be induced, chemical methods of alloxan- and streptozotocin-induced diabetes represent the most important and highly preferable experimental models for this pathological condition. Therefore, the aim of this article was to review the current knowledge related to quoted models of diabetes, including to this point available information about mechanism of action, particular time- and dose-dependent protocols, frequent problems, as well as major limitations linked to laboratory application of alloxan and sterptozotocin in inducing diabetes. Given that diabetes is known to be closely associated with serious health consequences it is of fundamental importance that current animal models for induction of diabetes should be continuously upgraded in order to improve overall prevention, diagnosis and treatment of this pathological condition.

  10. Numerical and experimental study of the interaction between two marine current turbines

    CERN Document Server

    Mycek, Paul; Germain, Grégory; Pinon, Grégory; Rivoalen, Elie

    2013-01-01

    The understanding of interaction effects between marine energy converters represents the next step in the research process that should eventually lead to the deployment of such devices. Although some a priori considerations have been suggested recently, very few real condition studies have been carried out concerning this issue. Trials were run on 1/30th scale models of three-bladed marine current turbine prototypes in a flume tank. The present work focuses on the case where a turbine is placed at different locations in the wake of a first one. The interaction effects in terms of performance and wake of the second turbine are examined and compared to the results obtained on the case of one single turbine. Besides, a three-dimensional software, based on a vortex method is currently being developed, and will be used in the near future to model more complex layouts. The experimental study shows that the second turbine is deeply affected by the presence of an upstream device and that a compromise between individu...

  11. Field and experimental constraints on the rheology of arc basaltic lavas: the January 2014 Eruption of Pacaya (Guatemala)

    Science.gov (United States)

    Soldati, A.; Sehlke, A.; Chigna, G.; Whittington, A.

    2016-06-01

    We estimated the rheology of an active basaltic lava flow in the field, and compared it with experimental measurements carried out in the laboratory. In the field we mapped, sampled, and recorded videos of the 2014 flow on the southern flank of Pacaya, Guatemala. Velocimetry data extracted from videos allowed us to determine that lava traveled at ˜2.8 m/s on the steep ˜45° slope 50 m from the vent, while 550 m further downflow it was moving at only ˜0.3 m/s on a ˜4° slope. Estimates of effective viscosity based on Jeffreys' equation increased from ˜7600 Pa s near the vent to ˜28,000 Pa s downflow. In the laboratory, we measured the viscosity of a representative lava composition using a concentric cylinder viscometer, at five different temperatures between 1234 and 1199 °C, with crystallinity increasing from 0.1 to 40 vol%. The rheological data were best fit by power law equations, with the flow index decreasing as crystal fraction increased, and no detectable yield strength. Although field-based estimates are based on lava characterized by a lower temperature, higher crystal and bubble fraction, and with a more complex petrographic texture, field estimates and laboratory measurements are mutually consistent and both indicate shear-thinning behavior. The complementary field and laboratory data sets allowed us to isolate the effects of different factors in determining the rheological evolution of the 2014 Pacaya flows. We assess the contributions of cooling, crystallization, and changing ground slope to the 3.7-fold increase in effective viscosity observed in the field over 550 m, and conclude that decreasing slope is the single most important factor over that distance. It follows that the complex relations between slope, flow velocity, and non-Newtonian lava rheology need to be incorporated into models of lava flow emplacement.

  12. Experimental constraints on the rheology, eruption, and emplacement dynamics of analog lavas comparable to Mercury's northern volcanic plains

    Science.gov (United States)

    Vetere, F.; Rossi, S.; Namur, O.; Morgavi, D.; Misiti, V.; Mancinelli, P.; Petrelli, M.; Pauselli, C.; Perugini, D.

    2017-07-01

    We present new viscosity measurements of a synthetic silicate system considered an analogue for the lava erupted on the surface of Mercury. In particular, we focus on the northern volcanic plains (NVP), which correspond to the largest lava flows on Mercury and possibly in the Solar System. High-temperature viscosity measurements were performed at both superliquidus (up to 1736 K) and subliquidus conditions (1569-1502 K) to constrain the viscosity variations as a function of crystallinity (from 0 to 28%) and shear rate (from 0.1 to 5 s-1). Melt viscosity shows moderate variations (4-16 Pa s) in the temperature range of 1736-1600 K. Experiments performed below the liquidus temperature show an increase in viscosity as shear rate decreases from 5 to 0.1 s-1, resulting in a shear thinning behavior, with a decrease in viscosity of 1 log unit. The low viscosity of the studied composition may explain the ability of NVP lavas to cover long distances, on the order of hundreds of kilometers in a turbulent flow regime. Using our experimental data we estimate that lava flows with thickness of 1, 5, and 10 m are likely to have velocities of 4.8, 6.5, and 7.2 m/s, respectively, on a 5° ground slope. Numerical modeling incorporating both the heat loss of the lavas and its possible crystallization during emplacement allows us to infer that high effusion rates (>10,000 m3/s) are necessary to cover the large distances indicated by satellite data from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging spacecraft.

  13. Comparison of experimental and theoretical reaction rail currents, rail voltages, and airgap fields for the linear induction motor research vehicle

    Science.gov (United States)

    Elliott, D. G.

    1977-01-01

    Measurements of reaction rail currents, reaction rail voltages, and airgap magnetic fields in tests of the Linear Induction Motor Research Vehicle (LIMRV) were compared with theoretical calculations from the mesh/matrix theory. It was found that the rail currents and magnetic fields predicted by the theory are within 20 percent of the measured currents and fields at most motor locations in most of the runs, but differ by as much as a factor of two in some cases. The most consistent difference is a higher experimental than theoretical magnetic field near the entrance of the motor and a lower experimental than theoretical magnetic field near the exit. The observed differences between the theoretical and experimental magnetic fields and currents do not account for the differences of as much as 26 percent between the theoretical and experimental thrusts.

  14. Experimental constraints on Fe isotope fractionation during magnetite and Fe carbonate formation coupled to dissimilatory hydrous ferric oxide reduction

    Science.gov (United States)

    Johnson, Clark M.; Roden, Eric E.; Welch, Susan A.; Beard, Brian L.

    2005-02-01

    , magnetite from BIFs that has δ 56Fe ≤0‰ apparently requires formation from aqueous Fe(II) that had very low δ 56Fe values. Based on this experimental study, formation of low-δ 56Fe Fe(II) aq in nonsulfidic systems seems most likely to have been produced by dissimilatory reduction of ferric oxides by Fe(III)-reducing bacteria.

  15. Ca(Ti,Si)O3 Diamond Inclusions Crystallized From Carbonate Melts in the Transition Zone: Experimental Constraints

    Science.gov (United States)

    Armstrong, L. S.; Walter, M. J.; Keshav, S.; Bulanova, G.; Pickles, J.; Lord, O. T.; Lennie, A.

    2007-12-01

    Composite diamond inclusions consisting of coexisting endmember CaSiO3 and CaTiO3 are rare but occur in diamond populations from Juina, Brazil1-2. Phase relations show that above ~9 GPa (at 1500 K) a perovskite-structured solid solution exists between these endmembers, while at lower pressures intermediate compositions produce coexisting CaTiO3-perovskite and CaSiO3 in the walstromite structure3. Inclusions with `perovskite' stoichiometry are commonly interpreted as fragments of solid mantle from the transition zone or lower mantle4-6. Here we report on two composite diamond inclusions from Juina kimberlite, and can effectively eliminate a subsolidus origin on the basis of experimental mineral phase relations. Instead, based on new melting experiments we find that the inclusions most likely crystallized directly from Ca-rich carbonate melts. Like other workers1-2 we interpret the composite inclusions as exsolution products of a high-pressure Ca(Ti,Si)O3 perovskite stable in the transition zone. Our bulk inclusion compositions are estimated to contain 50- 65 mol% CaTiO3, and are remarkably low in MgSiO3 component at less than 0.2 mol%. Experiments have shown that in peridotite or eclogite lithologies, Ca-rich perovskite in equilibrium with an MgSiO3-phase (majorite or Mg-perovskite) have about 3 to 7 mol% MgSiO37-8. Here we report on new subsolidus laser-heated diamond anvil cell experiments at 20-50 GPa in the ternary system CaSiO3-CaTiO3-MgSiO3 that bracket the CaTi-rich limb of the solvus between Ca- and Mg-rich perovskites. All experiments were made at 2000 (±200) K for 45-75 min, and were analysed using synchrotron micro-focus X-ray diffraction. We find that the solubility of MgSiO3 in CaTi-perovskite solid solutions increases significantly with increasing CaTiO3 component. Thus, Ti-rich calcium perovskite in peridotite or eclogite lithologies should have very high, not exceptionally low, MgSiO3 component. Accordingly, a subsolidus paragenesis is unlikely for

  16. Experimental constraints on the origin of compositional variations in the adakite-TTG-sanukitoid-HMA family of granitoids

    Science.gov (United States)

    Rapp, R. P.

    2003-04-01

    The current debate over whether or not Archean granitoids, including the TTG (tonalite-trondhjemite-granodiorite) and sanukitoid (high-Mg diorite) suites, are compositional analogues of modern day arc magmas related to "hot" subduction (adakites and high-Mg andesites, HMA), is for the most part an issue of semantics, the consequence of a definition for "adakite" that is too loose. That is not to say that the debate doesn't have important implications for the geodynamic setting in which growth of the Archean continental crust took place. Smithies (2000) and Martin (2002) both show that early-mid Archean (3.0--3.8 Ga) granitoids are generally restricted to low-Mg# TTG (with Mg# pressure interval of 1--4 GPa, have shown that low-moderate degrees of melting (˜10--40%) produces granitoid liquids with major- and trace-element characteristics comparable to both Archean TTG and low-Mg# adakite. These liquids are in equilibrium with garnet-bearing (garnet amphibolite or eclogite) crystalline residues; the mineral phases present in these residues (garnet, clinopyroxene, ± amphibole) impart to the melts the distinctive geochemical fingerprint that has come to be associated with both TTG and adakite. Experiments in which these "pristine" melts of garnet-bearing metabasalt are allowed to react with and assimilate mantle peridotite, simulating melt-rock reaction across the slab-wedge interface in modern subduction zones, or at the base of evolving Archean cratons, whatever the tectonic setting, produce hybridized granitoids resembling sanukitoids and HMAs. Assimilation of peridotite causes the Mg# of hybridizedTTG melts to increase, abundances of Cr and Ni to increase, SiO_2 to decrease, and the molar ratio [Al/(Ca+Na+K)] to decrease, but important trace element ratios (e.g., La/Yb, Sr/Y, Th/U) remain relatively unchanged, and primitive-mantle normalized abundance patterns of trace elements parallel those of the initial liquids. In terms of major- and trace-elements, therefore

  17. Current Parental Depression and Offspring Perceived Self-Competence: A Quasi-Experimental Examination

    Science.gov (United States)

    Class, Quetzal A.; D’Onofrio, Brian M.; Singh, Amber L.; Ganiban, Jody M.; Spotts, E. L.; Lichtenstein, Paul; Reiss, David; Neiderhiser, Jenae M.

    2013-01-01

    A genetically-informed, quasi-experimental design was used to examine the genetic and environmental processes underlying associations between current parental depressive symptoms and offspring perceived self-competence. Participants, drawn from a population-based Swedish sample, were 852 twin pairs and their male (52%) and female offspring aged 15.7 ± 2.4 years. Parental depressive symptoms were measured using the Center for Epidemiological Studies Depression scale. Offspring perceived self-competence was measured using a modified Harter Perceived Competence Scale. Cousin comparisons and Children of Twins (CoT) designs suggested that associations between maternal depressive symptoms and offspring perceived self-competence were due to shared genetic/environmental liability. The mechanism responsible for father-offspring associations, however, was independent of genetic factors and of extended-family environmental factors, supporting a causal inference. Thus, mothers and fathers may impact offspring perceived self-competence via different mechanisms and unmeasured genetic and environmental selection factors must be considered when studying the intergenerational transmission of cognitive vulnerabilities for depression. PMID:22692226

  18. Comparison of experimental and theoretical gain-current relations in GaInP quantum well lasers

    Energy Technology Data Exchange (ETDEWEB)

    Smowton, P.M.; Chow, W.W.; Blood, P.

    2000-01-10

    The authors compare the results of a microscopic laser theory with gain and recombination currents obtained from experimental spontaneous emission spectra. The calculated absorption spectrum is first matched to that measured on a laser, ensuring that the quasi-Fermi levels for the calculation and the experiment (spontaneous emission and gain) are directly related. This allows one to determine the inhomogeneous broadening in their experimental samples. The only other inputs to the theory are literature values of the bulk material parameter. The authors then estimate the non-radiative recombination current associated with the well and wave-guide core from a comparison of measured and calculated recombination currents.

  19. First Experimental Constraints on the Interference of 3/2+ Resonances in the 18F(p, ?)15O Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Chae, Kyung Yuk [ORNL; Bardayan, Daniel W [ORNL; Blackmon, Jeff C [ORNL; Gregory, Darren R [ORNL; Guidry, Mike W [ORNL; Johnson, Micah [ORNL; KOZUB, RAYMOND L [ORNL; Livesay, Jake [ORNL; Ma, Zhanwen [ORNL; Nesaraja, Caroline D [ORNL; Pain, Steven D [ORNL; Paulauskas, Stanley V [ORNL; Porter-Peden, Matthew D [ORNL; Shriner, Jr., John F [ORNL; Smith, Nathan A [ORNL; Smith, Michael Scott [ORNL; Thomas, Jeffrey S [ORNL

    2006-06-01

    The interference effects among J{sup {pi}}=3/2+ resonances in the {sup 18}F+p system have not been previously measured. R-matrix calculations show that the cross sections above the E{sub c.m.}=665 keV resonance are sensitive to the interference between the E{sub c.m.}=8, 38, and 665 keV resonances. An excitation function for the {sup 1}H({sup 18}F,{alpha}){sup 15}O reaction has been measured in the energy range of E{sub c.m.}=663-877 keV using radioactive 18F beams at the Holifield Radioactive Ion Beam Facility (HRIBF). By comparing the observed cross sections with the R-matrix calculations, we provide the first experimental constraints on the interference. Upper limits on proton widths ({Gamma}{sub p}) of the E{sub c.m.}=827 and 842 keV resonances have been set as well.

  20. Experimental Measurement of Asymmetric Fluctuations of Poloidal Magnetic Field in Damavand Tokomak at Different Plasma Currents

    Science.gov (United States)

    Moslehi-Fard, Mahmoud; Alinejad, Naser; Rasouli, Chapar; Sadigzadeh, Asghar

    2012-08-01

    Toroidal and Poloidal magnetic fields have an important effect on the tokomak topology. Damavand Tokomak is a small size tokomak characterized with k = 1.2, B t = 1T, R 0 = 36 cm, maximum plasma current is about 35 KA with a discharge time of 21 ms. In this experimental work, the variation of poloidal magnetic field on the torodial cross section is measured and analyzed. In order to measure the polodial magnetic field, 18 probes were installed on the edge of tokomak plasma with ∆θ = 18°, while a limiter was installed inside the torus. Plasma current, I p, induces a polodial magnetic field, B p, smaller than the torodial magnetic field B t. Magnetic lines B produced as a combination of B t and B p, are localized on the nested toroidal magnetic surfaces. The presence of polodial magnetic field is necessary for particles confinement. Mirnov oscillations are the fluctuations of polodial magnetic field, detected by magnetic probes. Disrupted instability in Tokomak typically starts with mirnov oscillations which appear as fluctuations of polodial magnetic field and is detected by magnetic probes. Minor disruptions inside the plasma can contain principal magnetic islands and their satellites can cause the annihilation of plasma confinement. Production of thin layer of turbulent magnetic field lines cause minor disruption. Magnetic limiter may cause the deformation of symmetric equilibrium configuration and chaotic magnetic islands reveal in plasma occurring in thin region of chaotic field lines close to their separatrix. The width of this chaotic layer in the right side of poloidal profile of Damavand Tokomak is smaller than the width in the left side profile because of Shafranov displacement. Ergodic region in the left side of profile develops a perturbation on the magnetic polodial field lines, B p, that are greater in magnitude than that in the right side, although the values of B p on the left side are smaller than that on the right side of the profile. The Left

  1. Experimental study of a high-current FEM with a broadband microwave system

    Energy Technology Data Exchange (ETDEWEB)

    Denisov, G.G.; Bratman, V.L.; Ginzburg, N.S. [Institute of Applied Physics, Nizhny Novgorod (Russian Federation)] [and others

    1995-12-31

    One of the main features of FELs and FEMs is the possibility of fast and wideband tuning of the resonant frequency of active media, which can be provided by changing the particle energy. For a frequency adjustable FEM-oscillator, a broadband microwave system, which is simply combined with an electron-optical FEM system and consists of an oversized waveguide and reflectors based on the microwave beams multiplication effect has been proposed and studied successfully in {open_quotes}cold{close_quotes} measurements. Here, the operating ability of a cavity, that includes some key elements of the broadband microwave system, was tested in the presence of an electron beam. To provide large particle oscillation velocities in a moderate undulator field and the presence of a guide magnetic field, the FEM operating regime of double resonance was chosen. In this regime the cyclotron as well as undulator resonance conditions were satisfied. The FEM-oscillator was investigated experimentally on a high-current accelerator {open_quotes}Sinus-6{close_quotes} that forms an electron beam with particle energy 500keV and pulse duration 25ns. The aperture with a diameter 2.5mm at the center of the anode allows to pass through only the central fraction of the electron beam with a current about 100A and a small spread of longitudinal velocities of the particles. Operating transverse velocity was pumped into the electron beam in the pulse plane undulator of a 2.4cm period. The cavity with a frequency near 45GHz consists of a square waveguide and two reflectors. The broadband up-stream reflector based on the multiplication effect had the power reflectivity coefficient more than 90% in the frequency band 10% for the H{sup 10} wave of the square waveguide with the maximum about 100% at a frequency 45GHz. The down-stream narrow-band Bragg reflector had the power reflection coefficient approximately 80% in the frequency band of 4% near 45GHz for the operating mode.

  2. 'I think it will eventually be done away with': Attitudes among healthcare professionals towards the current system of animal experimentation.

    Science.gov (United States)

    Dignon, Andrée

    2016-08-01

    This article describes a study of attitudes to the current system of animal experimentation (for the production of health interventions) among 52 UK healthcare professionals. These healthcare professionals participated in three separate focus groups (of 18, 17 and 17 participants) and were invited to respond to the question 'what is your opinion about the current system of animal testing?' The study focused specifically on their views of the current system (rather than their views of animal testing in general). The healthcare professionals were critical of the current system, particularly with regard to regulation, secrecy, validity, unnecessary suffering and welfare. © The Author(s) 2014.

  3. Two current experimental problems in heavy lepton physics: tau decay modes and close mass pairs

    Energy Technology Data Exchange (ETDEWEB)

    Perl, M.L.

    1987-08-01

    This paper investigates tau lepton decay modes and close-mass lepton pairs. The major part of the paper discusses branching functions from experimental and theoretical viewpoints. Finally, the lack of experimental signatures of close-mass lepton pairs are reviewed. 15 refs., 2 figs., 11 tabs. (JDH)

  4. Behavior of a DC zero-flux current sensor; Magnetic field analysis and comparison with experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Campostrini, P.; Sonato, P. (Istituto Gas Ionizzati del CNR, Padova (IT))

    1991-09-01

    In this paper the magnetic section of the finite-element ANSYS code, and in particular its optimization feature has been used to predict the behaviour of a zero-flux current sensor, briefly described, which is intended to be used in a fusion experiment to measure pulsed currents up to 50 kA, over a bandwidth from DC to 10 k Hz. The computed results fit well with those coming from experimental tests performed on a prototype.

  5. Faculty perceptions of the strengths, weaknesses and future prospects of the current medical undergraduate experimental physiology curriculum in Gujarat, India.

    Science.gov (United States)

    Paralikar, Swapnil; Shah, Chinmay

    2015-01-01

    Over the past several years, an opinion has emerged in India that the current practical curricula in medical schools fail to meet many of the objectives for which they were instituted. Hence, this study has assessed the perception of physiology faculty members regarding the current experimental physiology curriculum in one Indian state, Gujarat. The faculty were of the opinion that many of the topics currently taught in experimental physiology (amphibian nerve-muscle and heart muscle experiments) were outdated and clinically irrelevant: Therefore, the faculty advocated that duration of teaching time devoted to some of these topics should be reduced and topics with clinical relevance should be introduced at the undergraduate level. The faculty also felt that more emphasis should be laid on highlighting the clinical aspect related to each concept taught in experimental physiology . Moreover, a majority of faculty members were in favour of replacing the current practice in Gujarat of teaching experimental physiology only by explanation of graphs obtained from experiments conducted in the previous years, with computer assisted learning in small groups.

  6. Theoretical and Experimental Study of the Primary Current Distribution in Parallel-Plate Electrochemical Reactors

    Science.gov (United States)

    Vazquez Aranda, Armando I.; Henquin, Eduardo R.; Torres, Israel Rodriguez; Bisang, Jose M.

    2012-01-01

    A laboratory experiment is described to determine the primary current distribution in parallel-plate electrochemical reactors. The electrolyte is simulated by conductive paper and the electrodes are segmented to measure the current distribution. Experiments are reported with the electrolyte confined to the interelectrode gap, where the current…

  7. Experimental Phenomena of Improved Ohmic Confinement Induced by Modulated Toroidal Current on the HT-7 Tokamak

    Institute of Scientific and Technical Information of China (English)

    毛剑珊; 罗家融; P.Phillips; 赵君煜; 揭银先; 吴振伟; 胡立群; 李建刚

    2002-01-01

    The phenomena of improved ohmic confinement have been observed during the modulation of the toroidal curranton the Hefei superconducting Tokamak-7 (HT-7). In the experiment, the programming ohmic heating field wasmodulated. A toroidal frequency-modulated current induced by modulated loop voltage was added on the plasmaequilibrium current. The ratio of ac amplitude of the plasma current to the main plasma current is about 12-30%.These improved plasma confinement phenomena include the facts that the average electron density and the centralelectron temperature both increase, the Dα radiation from the edge is reduced, the magnetohydrodynamics isobviously suppressed by oscillating plasma current, eand the global energy confinement time increases by 27-45%o.It is found that the faster the modulation is, the more effective the improved ohmic confinement phase.

  8. Experimental study on directional solidification of Al-Si alloys under the influence of electric currents

    Science.gov (United States)

    Räbiger, D.; Zhang, Y.; Galindo, V.; Franke, S.; Willers, B.; Eckert, S.

    2016-07-01

    The application of electric currents during solidification can cause grain refinement in metallic alloys. However, the knowledge about the mechanisms underlying the decrease in grain size remains fragmentary. This study considers the solidification of Al-Si alloys under the influence of electric currents for the configuration of two parallel electrodes at the free surface. Solidification experiments were performed under the influence of both direct currents (DC) and rectangular electric current pulses (ECP). The interaction between the applied current and its own induced magnetic field causes a Lorentz force which produces an electro-vortex flow. Numerical simulations were conducted to calculate the Lorentz force, the Joule heating and the induced melt flow. The numerical predictions were confirmed by isothermal flow measurements in eutectic GaInSn. The results demonstrate that the grain refining effect observed in our experiments can be ascribed solely to the forced melt flow driven by the Lorentz force.

  9. Experimentally determined mechanical properties of, and models for, the periodontal ligament: critical review of current literature.

    Science.gov (United States)

    Fill, Ted S; Carey, Jason P; Toogood, Roger W; Major, Paul W

    2011-01-01

    Introduction. This review is intended to highlight and discuss discrepancies in the literature of the periodontal ligament's (PDL) mechanical properties and the various experimental approaches used to measure them. Methods. Searches were performed on biomechanical and orthodontic publications (in databases: Compendex, EMBASE, MEDLINE, PubMed, ScienceDirect, and Scopus). Results. The review revealed that significant variations exist, some on the order of six orders of magnitude, in the PDL's elastic constants and mechanical properties. Possible explanations may be attributable to different experimental approaches and assumptions. Conclusions. The discrepancies highlight the need for further research into PDL properties under various clinical and experimental loading conditions. Better understanding of the PDL's biomechanical behavior under physiologic and traumatic loading conditions might enhance the understanding of the PDL's biologic reaction in health and disease. Providing a greater insight into the response of the PDL would be instrumental to orthodontists and engineers for designing more predictable, and therefore more efficacious, orthodontic appliances.

  10. Unit commitment considering alternating current power flow constraints%交流潮流约束下的机组组合求解

    Institute of Scientific and Technical Information of China (English)

    潘志远; 韩学山; 刘超男

    2012-01-01

    With the parallel development of distributed generation technology and large power grid technology, a great amount of renewable energy generation was introduced to the electrical power grid. Under this circumstance, a unit commitment model was established by considering the constraints of transmission safety using AC (alternating current) power flow. This model also involved reactive and voltage constraints, as well as safe operation limits of generators. According to the Benders decomposition, the model was decomposed into a master problem and a sub-problem. The master problem could solve the unit commitment without AC constraints, and then the sub-problem could check the AC constraints according to the result of the master problem. Benders cuts might develop from the sub problem, and the cuts would form additional associated constraints, which could connect the master problem and the sub problem. Simulation results of modified IEEE-14 buses case proved that the proposed method could effectively solve unit commitment problems with constraints of AC power flow.%针对当前大电网与分布式发电并进,可再生资源发电大量接入的电网发展格局,构建交流潮流约束下的机组组合模型,在传统考虑有功网络安全约束的基础上,引入无功电压的制约,并计及机组的安全运行极限。依据Benders分解思想,将该模型分解为主、子两个问题,主问题为单母线模型机组组合,子问题为交流潮流约束的检验,通过子问题导引的Benders割形成主、子问题之间关联的附加约束。修正的IEEE-14节点仿真结果表明,该方法能够有效解决交流潮流约束下的机组组合问题。

  11. Experimental evaluation of IGBT junction temperature measurement via peak gate current

    DEFF Research Database (Denmark)

    Baker, Nick; Munk-Nielsen, Stig; Iannuzzo, Francesco

    2015-01-01

    Temperature sensitive electrical parameters allow junction temperature measurements on power semiconductors without modification to module packaging. The peak gate current has recently been proposed for IGBT junction temperature measurement and relies on the temperature dependent resistance of th...

  12. Currents, HF Radio-derived, Monterey Bay, 25 hr, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 25 hour running average of the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN...

  13. Currents, HF Radio-derived, Ano Nuevo, Normal Model, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements, with missing values filled in by a normal...

  14. Currents, HF Radio-derived, SF Bay Outlet, 25 hr, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 25 hour running average of the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN...

  15. Currents, HF Radio-derived, SF Bay, 33 hr, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 33 hour running average of the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN...

  16. Currents, HF Radio-derived, Bodega Bay, 25 hr, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 25 hour running average of the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN...

  17. Currents, HF Radio-derived, Ano Nuevo, 25 hr, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 25 hour running average of the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN...

  18. Currents, HF Radio-derived, Ano Nuevo, Normal Model, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements, with missing values filled in by a normal model....

  19. Currents, HF Radio-derived, Ano Nuevo, 25 hr, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 25 hour running average of the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN...

  20. Currents, HF Radio-derived, SF Bay Outlet, Normal Model, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements, with missing values filled in by a normal model....

  1. Experimental pain processing in individuals with cognitive impairment: current state of the science

    DEFF Research Database (Denmark)

    Defrin, R; Amanzio, Martina; de Tomasso, M

    2015-01-01

    to cognitively unimpaired individuals. Our current understanding of the neurobiological mechanisms underpinning these alterations is limited, but may be enhanced through the use of animal models of CI which also exhibit alterations in nociceptive responding. Further research employing additional behavioural...

  2. Currents, HF Radio-derived, Monterey Bay, Normal Model, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements, with missing values filled in by a normal model....

  3. Currents, HF Radio-derived, Monterey Bay, Normal Model, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements, with missing values filled in by a normal...

  4. Currents, HF Radio-derived, SF Bay Outlet, 25 hr, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 25 hour running average of the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN...

  5. Currents, HF Radio-derived, Bodega Bay, 25 hr, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 25 hour running average of the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN...

  6. Currents, HF Radio-derived, Monterey Bay, 25 hr, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 25 hour running average of the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN...

  7. Currents, HF Radio-derived, SF Bay Outlet, Normal Model, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements, with missing values filled in by a normal...

  8. Single-Case Experimental Designs: A Systematic Review of Published Research and Current Standards

    Science.gov (United States)

    Smith, Justin D.

    2012-01-01

    This article systematically reviews the research design and methodological characteristics of single-case experimental design (SCED) research published in peer-reviewed journals between 2000 and 2010. SCEDs provide researchers with a flexible and viable alternative to group designs with large sample sizes. However, methodological challenges have…

  9. An Introduction to 'Creativity Constraints'

    DEFF Research Database (Denmark)

    Onarheim, Balder; Biskjær, Michael Mose

    2013-01-01

    Constraints play a vital role as both restrainers and enablers in innovation processes by governing what the creative agent/s can and cannot do, and what the output can and cannot be. Notions of constraints are common in creativity research, but current contributions are highly dispersed due to n...

  10. Transcranial direct-current stimulation induced in stroke patients with aphasia: a prospective experimental cohort study

    Directory of Open Access Journals (Sweden)

    Michele Devido Santos

    Full Text Available CONTEXT AND OBJECTIVE: Previous animal and human studies have shown that transcranial direct current stimulation can induce significant and lasting neuroplasticity and may improve language recovery in patients with aphasia. The objective of the study was to describe a cohort of patients with aphasia after stroke who were treated with transcranial direct current stimulation. DESIGN AND SETTING: Prospective cohort study developed in a public university hospital. METHODS: Nineteen patients with chronic aphasia received 10 transcranial direct current stimulation sessions lasting 20 minutes each on consecutive days, using a current of 2 mA. The anode was positioned over the supraorbital area and the cathode over the contralateral motor cortex. The following variables were analyzed before and after the 10 neuromodulation sessions: oral language comprehension, copying, dictation, reading, writing, naming and verbal fluency. RESULTS: There were no adverse effects in the study. We found statistically significant differences from before to after stimulation in relation to simple sentence comprehension (P = 0.034, naming (P = 0.041 and verbal fluency for names of animals (P = 0.038. Improved scores for performing these three tasks were seen after stimulation. CONCLUSIONS: We observed that excitability of the primary motor cortex through transcranial direct current stimulation was associated with effects on different aspects of language. This can contribute towards future testing in randomized controlled trials.

  11. Single-Case Experimental Design: Current Standards and Applications in Occupational Therapy.

    Science.gov (United States)

    Lane, Justin D; Ledford, Jennifer R; Gast, David L

    Occupational therapy is a field with a long-standing history of recommending and implementing interventions designed to improve the quality of life of clients with disabilities. Often, the interventions are individualized to meet the needs of this diverse group of clients in dynamic settings. Identifying effective and efficient interventions for such a diverse group of clients and settings requires a flexible research approach. Single-case experimental designs (SCEDs) allow practitioners and researchers to answer experimental questions within the context of rigorous research designs. The purpose of this article is to highlight the similarities between the mission of occupational therapy and SCEDs. Recommendations for designing single-case studies with the framework provided by the Single-Case Reporting Guideline in Behavioral Interventions are provided. In addition, common problems and proposed solutions, along with implications for practitioners and researchers, are provided. Copyright © 2017 by the American Occupational Therapy Association, Inc.

  12. The case for a directional dark matter detector and the status of current experimental efforts

    CERN Document Server

    Ahlen, S; Battat, J B R; Billard, J; Bozorgnia, N; Burgos, S; Caldwell, T; Carmona, J M; Cebrián, S; Colas, P; Dafni, T; Daw, E; Dujmic, D; Dushkin, A; Fedus, W; Ferrer, E; Finkbeiner, D; Fisher, P H; Forbes, J; Fusayasu, T; Galan, J; Gamble, T; Ghag, C; Giomataris, Yu; Gold, M; Gomez, H; Gómez, M E; Gondolo, P; Green, A; Grignon, C; Guillaudin, O; Hagemann, C; Hattori, K; Henderson, S; Higashi, N; Ida, C; Iguaz, F J; Inglis, A; Irastorza, I G; Iwaki, S; Kaboth, A; Kabuki, S; Kadyk, J; Kallivayalil, N; Kubo, H; Kurosawa, S; Kudryavtsev, V A; Lamy, T; Lanza, R; Lawson, T B; Lee, A; Lee, E R; Lin, T; Loomba, D; López, J; Luzón, G; Manobu, T; Martoff, J; Mayet, F; McCluskey, B; Miller, E; Miuchi, K; Monroe, J; Morgan, B; Muna, D; Murphy, A St J; Naka, T; Nakamura, K; Nakamura, M; Nakano, T; Nicklin, G G; Nishimura, H; Niwa, K; Paling, S M; Parker, J; Petkov, A; Pipe, M; Pushkin, K; Robinson, M; Rodríguez, A; Rodríguez-Quintero, J; Sahin, T; Sanderson, R; Sanghi, N; Santos, D; Sato, O; Sawano, T; Sciolla, G; Sekiya, H; Slatyer, T R; Snowden-Ifft, D P; Spooner, N J C; Sugiyama, A; Takada, A; Takahashi, M; Takeda, A; Tanimori, T; Taniue, K; Tomas, A; Tomita, H; Tsuchiya, K; Turk, J; Tziaferi, E; Ueno, K; Vahsen, S; Vanderspek, R; Vergados, J; Villar, J A; Wellenstein, H; Wolfe, I; Yamamoto, R K; Yegoryan, H

    2010-01-01

    We present the case for a dark matter detector with directional sensitivity. This document was developed at the 2009 CYGNUS workshop on directional dark matter detection, and contains contributions from theorists and experimental groups in the field. We describe the need for a dark matter detector with directional sensitivity; each directional dark matter experiment presents their project's status; and we close with a feasibility study for scaling up to a one ton directional detector, which would cost around $150M.

  13. Experimental Test of Alternating-Current Zeeman Interference Effect in Ramsey Separated Oscillating Fields

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jun-Hai; WANG Feng-Zhi; YANG Dong-Hai

    2004-01-01

    An experimental test of ac Zeeman effect in an optically pumped caesium beam frequency standard is reported and analysed. An interference pattern of the atomic energy level shift as a function of the applied microwave field near the atomic transition frequency was observed. It was superimposed on the dispersion lineshape of a normal ac Zeeman effect. This effect was analysed with the atomic wavefunction phase analysing method.

  14. A study of experimental evaluations of neural network learning algorithms: current research practice

    OpenAIRE

    Prechelt, Lutz

    2007-01-01

    113 articles about neural network learning algorithms published in 1993 and 1994 are examined for the amount of experimental evaluation they contain. Every third of them does employ not even a single realistic or real learning problem. Only 6% of all articles present results for more than one problem using real world data.Furthermore, one third of all articles does not present any quantitative comparison with a previously known algorithm. These results indicate that the q...

  15. Experimental study on bed-load sediment transport under irregular wave and current combined flow

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Using an irregularly oscillating tray and flume, a series of experiments are completed to evaluate bed-load sediment transport rate under irregular wave- current coexistent fild. Testing conditions include three interaction angles 0°, 45°, 90° and two kinds of median sizes (0.38 and 1.10 mm).The results of transport rate show that the net sediment transport rate can be expressed approximately as the function of the maximum bottom shear stress of waves, mean shear stress of current and the grain size.

  16. Experimental and theoretical analysis of an optical current sensor for high power systems

    Science.gov (United States)

    Brigida, A. C. S.; Nascimento, I. M.; Mendonça, S.; Costa, J. C. W. A.; Martinez, M. A. G.; Baptista, J. M.; Jorge, P. A. S.

    2013-03-01

    A magneto-optical sensor, using a dual quadrature polarimetric processing scheme, was evaluated for current metering and protection applications in high voltage lines. Sensor calibration and resolution were obtained in different operational conditions using illumination in the 1550-nm band. Results obtained indicated the feasibility of interrogating such sensor via the optical ground wire (OPGW) link installed in standard high power grids. The polarimetric bulk optical current sensor also was theoretically studied, and the effects of different sources of error considering practical deployment were evaluated. In particular, the interference from external magnetic fields in a tree-phase system was analyzed.

  17. Current methods of the modeling of experimental diabetes mellitus type 2: a literature review

    Directory of Open Access Journals (Sweden)

    Yu. M. Kolesnyk

    2016-01-01

    Full Text Available Background. Diabetes mellitus (DM became a major problem of the healthcare in Ukraine. The rapid increase in the incidence was noticed especially in recent decade. The treatment of diabetes and its complications become a difficult task. From this standpoint the experimental modeling of diabetes is rather essential. Using the experimental models gives the possibility to assess the significance of the activity of pharmacological substances or to find out new mechanism in the action of medicaments. The aim of this review is to light up the most studied and common experimental models of diabetes mellitus type 2 (T2DM in small rodents and find out their drawbacks. It is known the background of T2DM is the violation of the insulin homeostasis such as the resistance of peripheral tissues to insulin as well as the dysfunction of the pancreatic beta-cells, which both lead to appearance of such phenomena as the glucosetoxicity and the lipotoxicity. In the end they both could result in life threatening vascular complications. Considering the steady growth of T2DM patients, the development both of the drug and non-drug methods of its treatment with the high therapeutically efficiency and the perfect safety profile becomes essential. The most important stage of the search of new ways of influence on pathogenetic links of T2DM is the preclinical stage. From this standpoint the usage of experimental models of T2DM has a huge importance. There are a lot of models of T2DM developed by different scientists. These models could be spontaneous or be induced by different chemical diabetogenic substances, diet or surgical interventions or be a combination of methods listed above. Conclusions. We should underline the adequate modeling of DM2T is the necessary basis for the pre-clinical study of drug-based and not-drug methods of correction of the hyperglycemic states. Using different models makes it possible for infer the obtained experimental results to the society

  18. Experimental results of current distribution in Rutherford-type LHC cables

    CERN Document Server

    Verweij, A P

    2000-01-01

    Current distribution among the wires of multi-strand superconducting cables is an important item for accelerator magnets. A non-uniform distribution could cause additional field distortions in the magnet bore and can as well be one of the reasons of premature quenching. Since two years electrical measurements on superconducting Rutherford-type cables are performed at CERN as part of the reception tests for the Large Hadron Collider (LHC). Cable samples of 2.4 m length are tested at currents up to 32 kA, temperatures around 1.9 and 4.3 K, and fields up to 10 T, applied perpendicularly as well as parallel to the broad face of the cable. Last year, an array of 24 Hall probes was installed in the test set-up in order to measure the self-field of the cable samples along one cable pitch. Each of the probes measures the local field generated by the current in the strands close by, and the results of the all probes reflect therefore the distribution of the strand currents. Experiments are done varying the applied fie...

  19. Resonance Chiral Lagrangian Currents and Experimental Data for $\\tau^-\\to\\pi^{-}\\pi^{-}\\pi^{+}\

    CERN Document Server

    Nugent, I M; Roig, P; Shekhovtsova, O; Was, Z

    2013-01-01

    In this paper we document the modifications introduced to the previous version of the Resonance Chiral Lagrangian current ({\\it Phys.Rev.} {\\bf D86} (2012) 113008) of the $\\tau^\\pm \\to \\pi^\\pm \\pi^\\pm \\pi^\\mp \

  20. Experimental Study on the Influence of AC Stray Current on the Cathodic Protection of Buried Pipe

    Directory of Open Access Journals (Sweden)

    Qingmiao Ding

    2016-01-01

    Full Text Available The size of the damaged area of the coating and its position on the pipeline impacted the cathodic protection potential, and there was a damaged area of the greatest impact value. When damaged area was 300 mm2, the IR drop was the largest, and this situation could easily lead to inadequate protection; when the parallel spacing between pipeline and interference source was unchanged, the measured value curves of cathodic protection potential presented “U” shaped trend with the increasing stray current interference intensity. Under certain parallel spacing between pipeline and interference source, high alternating stray current intensity would cause serious negative offsets, so that the overprotection of the pipeline occurred, and make the coating crack; there was a parallel threshold length. When less than the threshold, the pipe-ground potential increases rapidly with the parallel length increasing. In order to judge whether a pipeline was interference by AC stray current and the risk of stray current corrosion, we should make a comprehensive analysis of the cathodic protection energizing potential, the switch-off potential, AC pipe-soil potential, IR drops, and so on.

  1. Psychological constraints on egalitarianism

    DEFF Research Database (Denmark)

    Kasperbauer, Tyler Joshua

    2015-01-01

    Debates over egalitarianism for the most part are not concerned with constraints on achieving an egalitarian society, beyond discussions of the deficiencies of egalitarian theory itself. This paper looks beyond objections to egalitarianism as such and investigates the relevant psychological...... processes motivating people to resist various aspects of egalitarianism. I argue for two theses, one normative and one descriptive. The normative thesis holds that egalitarians must take psychological constraints into account when constructing egalitarian ideals. I draw from non-ideal theories in political...... philosophy, which aim to construct moral goals with current social and political constraints in mind, to argue that human psychology must be part of a non-ideal theory of egalitarianism. The descriptive thesis holds that the most fundamental psychological challenge to egalitarian ideals comes from what...

  2. Protobacco Media Exposure and Youth Susceptibility to Smoking Cigarettes, Cigarette Experimentation, and Current Tobacco Use among US Youth.

    Directory of Open Access Journals (Sweden)

    Erika B Fulmer

    Full Text Available Youth are exposed to many types of protobacco influences, including smoking in movies, which has been shown to cause initiation. This study investigates associations between different channels of protobacco media and susceptibility to smoking cigarettes, cigarette experimentation, and current tobacco use among US middle and high school students.By using data from the 2012 National Youth Tobacco Survey, structural equation modeling was performed in 2013. The analyses examined exposure to tobacco use in different channels of protobacco media on smoking susceptibility, experimentation, and current tobacco use, accounting for perceived peer tobacco use.In 2012, 27.9% of respondents were never-smokers who reported being susceptible to trying cigarette smoking. Cigarette experimentation increased from 6.3% in 6th grade to 37.1% in 12th grade. Likewise, current tobacco use increased from 5.2% in 6th grade to 33.2% in 12th grade. Structural equation modeling supported a model in which current tobacco use is associated with exposure to static advertising through perception of peer use, and by exposure to tobacco use depicted on TV and in movies, both directly and through perception of peer use. Exposure to static advertising appears to directly increase smoking susceptibility but indirectly (through increased perceptions of peer use to increase cigarette experimentation. Models that explicitly incorporate peer use as a mediator can better discern the direct and indirect effects of exposure to static advertising on youth tobacco use initiation.These findings underscore the importance of reducing youth exposure to smoking in TV, movies, and static advertising.

  3. Erosion Control of Scour during Construction; Report 3. Experimental Measurements of Refraction, Diffraction, and Current Patterns Near Jetties.

    Science.gov (United States)

    1980-09-01

    predict the probable magnitude of (Continued) DD vi’Ra 03 1wom or INov OM @ISDETR Unclassified S.CUm TY CLAS-.lCATIO OF THIS PAS.. (..m 0. Yw...transport of the bottom material at the particular site. The purpose of this study was to obtain detailed and precise experimental data regarding wave...currents. This removal of material from around structures is often not compensated by an influx of additional material ; the result is scour, or

  4. Experimental investigations of electric current under transverse and longitudinal electric field in uniaxially deformed p-Ge

    Science.gov (United States)

    Abramov, A. A.; Akimov, V. I.; Dalakyan, A. T.; Tulupenko, Victor N.; Zaitsev, A. M.; Danilov, S. N.; Firsov, D. A.; Shalygin, V. A.

    1999-11-01

    Comparison between cases of longitudinal and transverse directions of uniaxial pressure and strong electric field, affected the bulk hole germanium, to use it for lasting in far IR region has been carried out. Conclusion about preference of crossed directions is made. Threshold pressure, at which stimulated radiation arises, independence of crystallographic direction, along which external influences are applied, is also discussed. The results of experimental investigations of the crossed directions of uniaxial pressure and electric current are given.

  5. Experimental study on a wide range of wave and current conditions of the WEPTOS Wave Energy Converter

    DEFF Research Database (Denmark)

    Pecher, Arthur; Kofoed, Jens Peter

    This report presents the results of an experimental study that was performed on small scale model that was a replication of the full-scale Weptos WEC intended for DanWEC. The tests were performed in the circular basin at FloWave at Edinburgh University in October 2014. The laboratory facilities h...... the capabilities to have simultaneously currents and waves from any possible direction and also to produce advanced wave specifications....

  6. Numerical simulation and experimental study of the hydrodynamics of a modeled reef located within a current

    Institute of Scientific and Technical Information of China (English)

    姜昭阳; 梁振林; 唐衍力; 黄六一; 于定勇; 姜曼松

    2010-01-01

    The hydrodynamic forces and flow field of artificial reef models in steady flow were numerically investigated using the RNG k–εturbulent model.The numerical simulation results are consistent with results observed by experimental means.A comparative study indicates that the corresponding errors of forces between calculated values and values observed in the experiment vary in the range of 2.3%–11.2%and that the corresponding errors of velocities vary in the range of 1.3%–15.8%. The flow field numerical result...

  7. Survey of Current Experimental Studies of Effects of Traditional Chinese Medicine on Peripheral Nerve Regeneration

    Institute of Scientific and Technical Information of China (English)

    WU Qun-li; LIANG Xiao-chun

    2006-01-01

    The repairing and regeneration of peripheral nerves is a very complex biological and cytological process, its mechanism is unclear so far, and thus results in the lack of specific and effectual therapy and medicament. Chinese herbs and their effective components have their own inimitable predominance in promoting peripheral nerve regeneration, such as their multi-factorial, multi-target and multi-functional action, abundant source, inexpensive, etc. In this paper, the experimental studies reported in recent 5 years concerning the effects of Chinese herbs or their active components on peripheral nerve repairing and regeneration are reviewed in respects of the integral level, cellular level, molecular level and gene level.

  8. Minimum quench power dissipation and current non-uniformity in international thermonuclear experimental reactor type NbTi cable-in-conduit conductor samples under direct current conditions

    Science.gov (United States)

    Rolando, G.; van Lanen, E. P. A.; Nijhuis, A.

    2012-05-01

    The level of current non-uniformity in NbTi cable-in-conduit conductors (CICCs) sections near the joints in combination with the magnetic field profile needs attention in view of proper joint design. The strand joule power and current distribution at quench under DC conditions of two samples of ITER poloidal field coil conductors, as tested in the SULTAN facility, and of the so called PFCI model coil insert, have been analyzed with the numerical cable model JackPot. The precise trajectories of all individual strands, joint design, cabling configuration, spatial distribution of the magnetic field, sample geometry, and experimentally determined interstrand resistance distributions have been taken into account. Although unable to predict the quench point due to the lack of a thermal-hydraulic routine, the model allows to assess the instantaneous strand power at quench and its local distribution in the cable once the quench conditions in terms of current and temperature are experimentally known. The analysis points out the relation of the above mentioned factors with the DC quench stability of both short samples and coils. The possible small scale and local electrical-thermal interactions were ignored in order to examine the relevance of such effects in the overall prediction of the CICC performance. The electromagnetic code shows an excellent quantitative predictive potential for CICC transport properties, excluding any freedom for matching the results. The influence of the local thermal effects in the modeling is identified as being marginal and far less than the generally accepted temperature margin for safe operation.

  9. Experimental Verification of Overlimiting Current by Surface Conduction and Electro-osmotic Flow in Microchannels

    CERN Document Server

    Nam, Sungmin; Heo, Joonseong; Lim, Geunbae; Bazant, Martin Z; Sung, Gunyong; Kim, Sung Jae

    2014-01-01

    Possible mechanisms of overlimiting current in unsupported electrolytes, exceeding diffusion limitation, have been intensely studied for their fundamental significance and applications to desalination, separations, sensing, and energy storage. In bulk membrane systems, the primary physical mechanism is electro-convection, driven by electro-osmotic instability on the membrane surface. It has recently been predicted that confinement by charged surfaces in microchannels or porous media favors two new mechanisms, electro-osmotic flow (EOF) and surface conduction (SC), driven by large electric fields in the depleted region acting on the electric double layers on the sidewalls. Here, we provide the first direct evidence for the transition from SC to EOF above a critical channel height, using in situ particle tracking and current-voltage measurements in a micro/nanofluidic device. The dependence of the over-limiting conductance on channel depth (d) is consistent with theoretical predictions, scaling as d^-1 for SC a...

  10. Experimental study on hydrodynamic characteristics of vertical-axis floating tidal current energy power generation device

    Science.gov (United States)

    Ma, Yong; Li, Teng-fei; Zhang, Liang; Sheng, Qi-hu; Zhang, Xue-wei; Jiang, Jin

    2016-10-01

    To study the characteristics of attenuation, hydrostatic towage and wave response of the vertical-axis floating tidal current energy power generation device (VAFTCEPGD), a prototype is designed and experiment is carried out in the towing tank. Free decay is conducted to obtain attenuation characteristics of the VAFTCEPGD, and characteristics of mooring forces and motion response, floating condition, especially the lateral displacement of the VAFTCEPGD are obtained from the towing in still water. Tension response of the #1 mooring line and vibration characteristics of the VAFTCEPGD in regular waves as well as in level 4 irregular wave sea state with the current velocity of 0.6 m/s. The results can be reference for theoretical study and engineering applications related to VAFTCEPGD.

  11. Foreign Languages in Vienna Primary Schools – in Mainstream Education and in Current Experimental Models

    Directory of Open Access Journals (Sweden)

    Renate Seebauer

    2015-05-01

    Full Text Available Starting with a short retrospective and an overview of the incorporation of foreign language learning into the Austrian curriculum for primary schools the paper in hand describes the current situation of foreign language teaching in primary schools as well as various current models of foreign language education in primary schools in Vienna (school year 1 to 4. In terms of objectives these models exceed the requirements of the curriculum of the formal education system or regard themselves as quantitative and qualitative enrichment. They follow different didactic approaches and/or site-specific characteristics and needs. The formulation of basic skills is to be understood as an attempt to find a common basis of output indicators and to facilitate the transition to secondary education. Although English is the most commonly chosen resp. offered language the paper also refers to school experiments that focus on Romance or Slavic languages or on languages of Austra’s neighbouring countries.

  12. Experimental investigation of quasiperiodic-chaotic-quasiperiodic-chaotic transition in a direct current magnetron sputtering plasma

    Energy Technology Data Exchange (ETDEWEB)

    Sabavath, Gopi Kishan; Banerjee, I.; Mahapatra, S. K., E-mail: skmahapatra@bitmesra.ac.in [Plasma Laboratory, Department of Physics, Birla Institute of Technology-Mesra, Ranchi 835215 (India); Shaw, Pankaj Kumar; Sekar Iyengar, A. N. [Plasma Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India)

    2015-08-15

    Floating potential fluctuations from a direct current magnetron sputtering plasma have been analysed using time series analysis techniques like phase space plots, power spectra, frequency bifurcation plot, etc. The system exhibits quasiperiodic-chaotic-quasiperiodic-chaotic transitions as the discharge voltage was increased. The transitions of the fluctuations, quantified using the largest Lyapunov exponent, have been corroborated by Hurst exponent and the Shannon entropy. The Shannon entropy is high for quasiperiodic and low for chaotic oscillations.

  13. Experimental studies on benzene carcinogenicity at the Bologna Institute of Oncology: current results and ongoing research.

    Science.gov (United States)

    Maltoni, C; Conti, B; Cotti, G; Belpoggi, F

    1985-01-01

    In 1977 Maltoni and Scarnato were the first to demonstrate that benzene is an experimental carcinogen in rats. With that and other experiments, Maltoni et al have shown that benzene administered by ingestion (stomach tube) or inhalation is a multipotential carcinogen in rats (of two different strains) and mice and produces a variety of tumors, namely: Zymbal gland carcinomas, oral and nasal cavity carcinomas, skin carcinomas, acanthomas, dysplasias and carcinomas of forestomach, mammary malignant tumors, hepatomas, liver angiosarcomas, hemolymphoreticular neoplasias, and pulmonary tumors. The incidence of Zymbal gland carcinomas and carcinomas of the oral and nasal cavities is affected by the length of treatment by inhalation and by the age of animals. However, the available epidemiological and experimental data at present do not provide precise information on the risk of doses around or below 10 ppm. Long-term carcinogenicity bioassays at 50, 25, 10, 5 and 1 ppm may be helpful for scientific risk assessment. In addition, these experiments have shown that toluene, xylene, and ethylbenzene, at high concentrations, cause an increase in the number of total malignant tumors.

  14. Single-Case Experimental Designs: A Systematic Review of Published Research and Current Standards

    Science.gov (United States)

    Smith, Justin D.

    2013-01-01

    This article systematically reviews the research design and methodological characteristics of single-case experimental design (SCED) research published in peer-reviewed journals between 2000 and 2010. SCEDs provide researchers with a flexible and viable alternative to group designs with large sample sizes. However, methodological challenges have precluded widespread implementation and acceptance of the SCED as a viable complementary methodology to the predominant group design. This article includes a description of the research design, measurement, and analysis domains distinctive to the SCED; a discussion of the results within the framework of contemporary standards and guidelines in the field; and a presentation of updated benchmarks for key characteristics (e.g., baseline sampling, method of analysis), and overall, it provides researchers and reviewers with a resource for conducting and evaluating SCED research. The results of the systematic review of 409 studies suggest that recently published SCED research is largely in accordance with contemporary criteria for experimental quality. Analytic method emerged as an area of discord. Comparison of the findings of this review with historical estimates of the use of statistical analysis indicates an upward trend, but visual analysis remains the most common analytic method and also garners the most support amongst those entities providing SCED standards. Although consensus exists along key dimensions of single-case research design and researchers appear to be practicing within these parameters, there remains a need for further evaluation of assessment and sampling techniques and data analytic methods. PMID:22845874

  15. Glazed clay pottery and lead exposure in Mexico: Current experimental evidence.

    Science.gov (United States)

    Diaz-Ruiz, Araceli; Tristán-López, Luis Antonio; Medrano-Gómez, Karen Itzel; Torres-Domínguez, Juan Alejandro; Ríos, Camilo; Montes, Sergio

    2017-11-01

    Lead exposure remains a significant environmental problem; lead is neurotoxic, especially in developing humans. In Mexico, lead in human blood is still a concern. Historically, much of the lead exposure is attributed to the use of handcrafted clay pottery for cooking, storing and serving food. However, experimental cause-and-effect demonstration is lacking. The present study explores this issue with a prospective experimental approach. We used handcrafted clay containers to prepare and store lemonade, which was supplied as drinking water to pregnant rats throughout the gestational period. We found that clay pots, jars, and mugs leached on average 200 µg/l lead, and exposure to the lemonade resulted in 2.5 µg/dl of lead in the pregnant rats' blood. Neonates also showed increased lead content in the hippocampus and cerebellum. Caspase-3 activity was found to be statistically increased in the hippocampus in prenatally exposed neonates, suggesting increased apoptosis in that brain region. Glazed ceramics are still an important source of lead exposure in Mexico, and our results confirm that pregnancy is a vulnerable period for brain development.

  16. Current and experimental treatments of Parkinson disease: A guide for neuroscientists.

    Science.gov (United States)

    Oertel, Wolfgang; Schulz, Jörg B

    2016-10-01

    Over a period of more than 50 years, the symptomatic treatment of the motor symptoms of Parkinson disease (PD) has been optimized using pharmacotherapy, deep brain stimulation, and physiotherapy. The arsenal of pharmacotherapies includes L-Dopa, several dopamine agonists, inhibitors of monoamine oxidase (MAO)-B and catechol-o-methyltransferase (COMT), and amantadine. In the later course of the disease, motor complications occur, at which stage different oral formulations of L-Dopa or dopamine agonists with long half-life, a transdermal application or parenteral pumps for continuous drug supply can be subscribed. Alternatively, the patient is offered deep brain stimulation of the subthalamic nucleus (STN) or the internal part of the globus pallidus (GPi). For a more efficacious treatment of motor complications, new formulations of L-Dopa, dopamine agonists, and amantadine as well as new MAO-B and COMT inhibitors are currently tested in clinical trials, and some of them already yielding positive results in phase 3 trials. In addition, non-dopaminergic agents have been tested in the early clinical phase for the treatment of motor fluctuations and dyskinesia, including adenosine A2A antagonists (istradefylline, preladenant, and tozadenant) and modulators of the metabolic glutamate receptor 5 (mGluR5 - mavoglurant) and serotonin (eltoprazine) receptors. Recent clinical trials testing coenzyme Q10, the dopamine agonist pramipexole, creatine monohydrate, pioglitazone, or AAV-mediated gene therapy aimed at increasing expression of neurturin, did not prove efficacious. Treatment with nicotine, caffeine, inosine (a precursor of urate), and isradipine (a dihydropyridine calcium channel blocker), as well as active and passive immunization against α-synuclein and inhibitors or modulators of α-synuclein-aggregation are currently studied in clinical trials. However, to date, no disease-modifying treatment is available. We here review the current status of treatment options for

  17. Topology Optimization with Stress Constraints

    NARCIS (Netherlands)

    Verbart, A.

    2015-01-01

    This thesis contains contributions to the development of topology optimization techniques capable of handling stress constraints. The research that led to these contributions was motivated by the need for topology optimization techniques more suitable for industrial applications. Currently, topolo

  18. An Experimental Investigation of Passive Variable-Pitch Vertical-Axis Ocean Current Turbine

    Directory of Open Access Journals (Sweden)

    Ridho Hantoro

    2011-04-01

    Full Text Available Vertical-axis hydrokinetic turbines with fixed pitch blades typically suffer from poor starting torque, low efficiency and shaking due to large fluctuations in both radial and tangential force with azimuth angle. Maximizing the turbine power output can be achieved only if the mechanism of generation of the hydrodynamic force on the blades is clearly identified and tools to design high-performance rotors are developed. This paper describes an initial experimental investigation to understand more of the performance on vertical-axis turbine related to the effect of fixed-pitch and passive variable-pitch application using airfoil NACA 0018. Comparative analysis according to aspects of rotation and tip speed ratios was discussed. Information regarding the changes of foil position in passive variable-pitch during rotation at a limited range of flow velocity variations test was obtained and analyzed.

  19. Current Status of Clinical and Experimental Researches on Cognitive Impairment in Diabetes

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This article reviews the clinical and experimental researches on cognitive impairment related to diabetes in the recent decade. Most clinical studies indicate that the cognitive impairment in patients with type 1 diabetes mellitus is related to recurrent hypoglycemia closely. There is little research about whether or not hyperglycemia is related to cognitive impairment in patients with type 1 diabetes mellitus. Most studies indicate that the cognitive impairment in type 2 diabetes involves multiple factors through multiple mechanisms, including blood glucose, blood lipid, blood pressure, level of insulin, medication, chronic complication, etc. But, there has been no large-scale, multi-center, randomized controlled clinical trial in China recently. And what is more, some problems exist in this field of research, such as the lack of golden criterion of cognitive function measurement, different population of studied objects, and incomprehensive handling of confounding factors. Experimental studies found that hippocampal long-term potentiation (LTP) was impaired,which were manifested by impairment of spatial memory and decreased expression of LTP, but its relation to hyperglycemia, the duration of diabetes, learning and memory has always been differently reported by different researches. Thus, there are a lot of unknown things to be explored and studied in order to clarify its mechanism. TCM has abundant clinical experience in treating cerebral disease with medicine that enforces the kidney and promotes wit. However, there has been no research on treating diabetic cognitive impairment,which requires work to be done actively and TCM to be put into full play, in order to improve the treatment of diabetes and enhance living quality of patients.

  20. An experimental study on counter current flow limitation in annular narrow gaps with large diameter

    Energy Technology Data Exchange (ETDEWEB)

    Park, Rae Joon; Jeong, Ji Whan; Lee, Sung Jin; Cho, Young Ro; Ha, Kwang Sun; Kim, Sang Baik; Kim, Hee Dong [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2002-04-01

    The present study intends to carry out CCFL experiment with the same gap size as the CHFG facility and suggest an empirical correlation in order to provide basic information useful to development of an empirical critical-power correlation. The present facility consists of water accumulator tank, test section, DC pump, air regulator, valves and sensors. Air and water are used as working fluids. The experiments are carried out at the atmospheric pressure. Differential pressure between the gap ends, liquid and gas phase flow rates, temperature, lower plenum pressure are measured.Measured values are expressed in terms of Wallis' parameter using gap size as a characteristic length. There is a big difference between the present experimental results and the Koizumi et al.'s results, but the present experimental results are very similar to the Richter et al.'s results. The present results agree well with the Osakabe and Kawasaki's results. In comparison of present experiments with the Koizumi et al.'s experiments, gap thickness is similar, but the diameter of the present is bigger than that of Koizumi et al.'s experiments. In comparison of present experiments with the Richter et al.'s experiments, diameter is similar, but the gap thickness of the present is smaller than that of Richter et al.'s experiments. It is judged from these results that correlation development on CCFL to consider gap thickness is reasonable at similar condition of diameter.The developed correlation will be used to develop the CHFG model. 36 refs., 26 figs., 7 tabs. (Author)

  1. Secondary current properties generated by wind-induced water waves in experimental conditions

    Directory of Open Access Journals (Sweden)

    Michio Sanjou

    2014-06-01

    Full Text Available Secondary currents such as the Langmuir circulation are of high interest in natural rivers and the ocean because they have striking impacts on scour, sedimentation, and mass transport. Basic characteristics have been well-studied in straight open-channel flows. However, little is known regarding secondary circulation induced by wind waves. The presented study describes the generation properties of wind waves observed in the laboratory tank. Wind-induced water waves are known to produce large scale circulations. The phenomenon is observed together with high-speed and low-speed streaks, convergence and divergence zones, respectively. Therefore, it is important to determine the hydrodynamic properties of secondary currents for wind-induced water waves within rivers and lakes. In this study, using two high-speed CMOS cameras, stereoscopic particle image velocimetry (PIV measurements were conducted in order to reveal the distribution of all three components of velocity vectors. The experiments allowed us to investigate the three-dimensional turbulent structure under water waves and the generation mechanism of large-scale circulations. Additionally, a third CMOS camera was used to measure the spanwise profile of thefree-surface elevation. The time-series of velocity components and the free-surface were obtained simultaneously. From our experiments, free-surface variations were found to influence the instantaneous velocity distributions of the cross-sectional plane. We also considered thegeneration process by the phase analysis related to gravity waves and compared the contribution of the apparent stress.

  2. New hadronic currents in TAUOLA: for confrontation with the experimental data

    CERN Document Server

    Was, Z

    2012-01-01

    The status of implementation of new hadronic currents into the Monte Carlo system for simulation of tau-lepton production and decay in high-energy accelerator experiments is reviewed. Since the tau-lepton conference in 2010 substantial progress was achieved: (i) For the TAUOLA Monte Carlo generator of tau-lepton decays, automated and simultaneous use of many versions of form factors for the calculation of optional weights for fits was developed and checked to work in the Belle and BaBar software environment. Alternative parameterizations of hadronic currents based on the Resonance Chiral approach are available now. This was achieved for more than 88% of the total tau hadronic width. (ii) the TAUOLA universal interface based on HepMC (the C++ event record) is available. This is the case for C++ users of PHOTOS Monte Carlo for radiative corrections in decays, as well. An algorithm for weighted events to explore spin effects in analysis of hard processes was prepared. (iii) Kernels featuring a complete first-ord...

  3. New hadronic currents in TAUOLA: for confrontation with the experimental data

    Energy Technology Data Exchange (ETDEWEB)

    Was, Z. [Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, 31-342 Cracow (Poland); CERN, 1211 Geneva (Switzerland)

    2012-04-15

    The status of implementation of new hadronic currents into the Monte Carlo system for simulation of {tau}-lepton production and decay in high-energy accelerator experiments is reviewed. Since the {tau}-lepton conference in 2010 substantial progress was achieved: (i) For the TAUOLA Monte Carlo generator of {tau}-lepton decays, automated and simultaneous use of many versions of form factors for the calculation of optional weights for fits was developed and checked to work in the Belle and BaBar software environment. Alternative parameterizations of hadronic currents based on the Resonance Chiral approach are available now. This was achieved for more than 88% of the total {tau} hadronic width. (ii) the TAUOLA universal interface based on HepMC (the C++ event record) is available. This is the case for C++ users of PHOTOS Monte Carlo for radiative corrections in decays, as well. An algorithm for weighted events to explore spin effects in analysis of hard processes was prepared. (iii) Kernels featuring a complete first-order matrix element are available now for PHOTOS users interested in decays of Z and W bosons. New tests with different options of matrix elements for those and for K{sub l3} decays are available as well. Presented results illustrate the status of the projects performed in collaboration with Zofia Czyczula, Nadia Davidson, Tomasz Przedzinski, Olga Shekhovtsova, Elzbieta Richter-Was, Pablo Roig, Qingjun Xu and others.

  4. An Experimental Study on the Darrieus-Savonius Turbine for the Tidal Current Power Generation

    Science.gov (United States)

    Kyozuka, Yusaku

    The Darrieus turbine is popular for tidal current power generation in Japan. It is simple in structure with straight wings rotating around a vertical axis, so that it has no directionality against the motion of tidal flow which changes its direction twice a day. However, there is one defect in the Darrieus turbine; its small starting torque. Once it stops, a Darrieus turbine is hard to re-start until a fairly fast current is exerted on it. To improve the starting torque of the Darrieus turbine used for tidal power generation, a hybrid turbine, composed of a Darrieus turbine and a Savonius rotor is proposed. Hydrodynamic characteristics of a semi-circular section used for the Savonius bucket were measured in a wind tunnel. The torque of a two bucket Savonius rotor was measured in a circulating water channel, where four different configurations of the bucket were compared. A combined Darrieus and Savonius turbine was tested in the circulating water channel, where the effect of the attaching angle between Darrieus wing and Savonius rotor was studied. Finally, power generation experiments using a 48 pole electric generator were conducted in a towing tank and the power coefficients were compared with the results of experiments obtained in the circulating water channel.

  5. Experimental and Numerical Study of Wave-Induced Long-Shore Currents on A Mild Slope Beach

    Institute of Scientific and Technical Information of China (English)

    SUN Tao; TAO Jian-hua

    2005-01-01

    The long-shore current distribution on a mild slope beach is studied by combining the numerical model and the physical experiment. The experiments of long-shore currents under the action of regular and irregular waves are conducted on mild beaches with different slopes in a wave basin. A numerical model is established, which includes a wave propagation model, a wave breaking model and a long-shore current model. The validity of the numerical model is proved by the comparison of its results with the results of the experimental model. It is concluded that the wave-induced long-shore current is influenced significantly by the incident wave height, the wave angle and the beach slope. Its application to the Bohai Bay indicates that the wave-induced currents have the same order of magnitude as the tide currents in the near-shore zone of mill slope beach. In the design of wastewater outfall locations on a mild-slope beach with shallow water of the Bohai Bay, the position of the outfall should be 10 km away from the shoreline, which is outside of the surf-zone.

  6. [Regeneration of endocrine gastroenteropancreatic system in experimental and clinical pathology: concept development and current problems].

    Science.gov (United States)

    Ivanova, V F

    2013-01-01

    Literature review contains the literature data and the results of author's own investigations describing the coming into being and the development of the concepts on the regeneration of endocrine gastroenteropancreatic (GEP) system under the conditions of norm, experimental and clinical pathology. Data analysis permitted to reveal the similarities and differences in the course of this process in various organs of the digestive system. Endocrine GEP system renewal occurs at different levels of its organization. At the tissue level, the endocrine cells renewal occurs via the transformation of exocrine cells into the endocrine ones and as a result of differentiation from stem cells via the "agranular" cell stage which are precursors of the endocrine cells. This pathway of regeneration is the major one after the damage. Regeneration at cellular level occurs through mitotic division of the differentiated endocrine cells (early stage of regeneration) and as a result of the formation granules with different hormonal profile in D-cells. At the intracellular level, the regeneration is realized through the intracellular structure restoration after their damage induced by the increase of cell functional activity accompanied by degranulation and dystrophic changes development

  7. Experimental Constraints on {\\gamma}-ray Pulsar Gap Models and the Pulsar GeV to Pulsar Wind Nebula TeV Connection

    CERN Document Server

    Abeysekara, A U

    2015-01-01

    The pulsar emission mechanism in the gamma-ray energy band is poorly understood. Currently, there are several models under discussion in the pulsar community. These models can be constrained by studying the collective properties of a sample of pulsars, which became possible with the large sample of gamma-ray pulsars discovered by the Fermi Large Area Telescope (Fermi-LAT). In this paper we develop a new experimental multi-wavelength technique to determine the beaming factor $\\left( f_\\Omega \\right)$ dependance on spin-down luminosity of a set of GeV pulsars. This technique requires three input parameters: pulsar spin-down luminosity, pulsar phase-averaged GeV flux and TeV or X-ray flux from the associated Pulsar Wind Nebula (PWN). The analysis presented in this paper uses the PWN TeV flux measurements to study the correlation between $f_\\Omega$ and $\\dot{E}$. The measured correlation has some features that favor the Outer Gap model over the Polar Cap, Slot Gap and One Pole Caustic models for pulsar emission i...

  8. Current experimental perspectives on the clinical progression of alcoholic liver disease.

    Science.gov (United States)

    Breitkopf, Katja; Nagy, Laura E; Beier, Juliane I; Mueller, Sebastian; Weng, Honglei; Dooley, Steven

    2009-10-01

    Chronic alcohol abuse is an important cause of morbidity and mortality throughout the world. Liver damage due to chronic alcohol intoxication initially leads to accumulation of lipids within the liver and with ongoing exposure this condition of steatosis may first progress to an inflammatory stage which leads the way for fibrogenesis and finally cirrhosis of the liver. While the earlier stages of the disease are considered reversible, cirrhotic destruction of the liver architecture beyond certain limits causes irreversible damage of the organ and often represents the basis for cancer development. This review will summarize current knowledge about the molecular mechanisms underlying the different stages of alcoholic liver disease (ALD). Recent observations have led to the identification of new molecular mechanisms and mediators of ALD. For example, plasminogen activator inhibitor 1 was shown to play a central role for steatosis, the anti-inflammatory adipokine, adiponectin profoundly regulates liver macrophage function and excessive hepatic deposition of iron is caused by chronic ethanol intoxication and increases the risk of hepatocellular carcinoma development.

  9. Experimental Estimating Deflection of a Simple Beam Bridge Model Using Grating Eddy Current Sensors

    Directory of Open Access Journals (Sweden)

    Hui Zhao

    2012-07-01

    Full Text Available A novel three-point method using a grating eddy current absolute position sensor (GECS for bridge deflection estimation is proposed in this paper. Real spatial positions of the measuring points along the span axis are directly used as relative reference points of each other rather than using any other auxiliary static reference points for measuring devices in a conventional method. Every three adjacent measuring points are defined as a measuring unit and a straight connecting bar with a GECS fixed on the center section of it links the two endpoints. In each measuring unit, the displacement of the mid-measuring point relative to the connecting bar measured by the GECS is defined as the relative deflection. Absolute deflections of each measuring point can be calculated from the relative deflections of all the measuring units directly without any correcting approaches. Principles of the three-point method and displacement measurement of the GECS are introduced in detail. Both static and dynamic experiments have been carried out on a simple beam bridge model, which demonstrate that the three-point deflection estimation method using the GECS is effective and offers a reliable way for bridge deflection estimation, especially for long-term monitoring.

  10. Structural Characterization of Phase Separation in Fe-Cr: A Current Comparison of Experimental Methods

    Science.gov (United States)

    Xu, Xin; Odqvist, Joakim; Colliander, Magnus Hörnqvist; Thuvander, Mattias; Steuwer, Axel; Westraadt, Johan E.; King, Stephen; Hedström, Peter

    2016-12-01

    Self-assembly due to phase separation within a miscibility gap is important in numerous material systems and applications. A system of particular interest is the binary alloy system Fe-Cr, since it is both a suitable model material and the base system for the stainless steel alloy category, suffering from low-temperature embrittlement due to phase separation. Structural characterization of the minute nano-scale concentration fluctuations during early phase separation has for a long time been considered a major challenge within material characterization. However, recent developments present new opportunities in this field. Here, we present an overview of the current capabilities and limitations of different techniques. A set of Fe-Cr alloys were investigated using small-angle neutron scattering (SANS), atom probe tomography, and analytical transmission electron microscopy. The complementarity of the characterization techniques is clear, and combinatorial studies can provide complete quantitative structure information during phase separation in Fe-Cr alloys. Furthermore, we argue that SANS provides a unique in-situ access to the nanostructure, and that direct comparisons between SANS and phase-field modeling, solving the non-linear Cahn Hilliard equation with proper physical input, should be pursued.

  11. Current radiological techniques used to evaluate unilateral partial ureteral obstruction: an experimental rabbit study.

    Science.gov (United States)

    Yazıcı, Mehmet; Celebi, Suleyman; Kuzdan, Özgür; Koçan, Hüseyin; Ayyıldız, Halil Suat; Bayrak, İlkay Koray; Bilgici, Meltem Ceyhan; Yapıcı, Oktay; Kefeli, Mehmet; Arıtürk, Ender

    2015-07-01

    The aim of this study was to evaluate functional and prognostic benefits of Doppler ultrasonography (DU), diuretic renal scintigraphy (DRS), and magnetic resonance urography (MRU) during diagnosis and follow-up of ureteropelvic junction obstruction (UPJO) and to examine apoptosis rates caused by UPJO in an experimental rabbit model. Twenty-four rabbits were divided randomly into two groups. The left kidneys of 15 rabbits from the first group underwent Ulm-Miller surgery to create UPJO, whereas the left kidneys of nine rabbits from the second group underwent sham surgery. A pressure flow study (Whitaker's test) was done during postoperative week 6. Based on the Whitaker test, the DU, DRS, and MRU findings were compared. The number of apoptotic renal cells was counted after death. The Whitaker test run during postoperative week 6 revealed obstructions in 15 rabbits from group 1; the nine rabbits of the sham group had no obstructions. Sensitivity and specificity of DRS were 93.3 and 88.8 %, respectively, and those of MRU were 93.3 and 88.8 %, respectively. The postoperative mean RI values were significantly higher than the preoperative values, associated with sensitivity of 86.6 % and specificity of 77.5 % for detecting UPJO. DRS, MRU, and RI could not predict UPJO in one (8 %), one (8 %), and two (16 %) kidneys, respectively. Likelihood ratio (LR) was 8.4 for MRU and scintigraphy, while for RI, LR was 3.9. Pathology specimens revealed that all kidneys with UPJO underwent apoptosis, and the number of apoptotic cells was significantly higher on the UPJO-created side than on the contralateral and in the sham group (p < 0.05). No test predicted all apoptosis related to UPJO. The RI, DRS, and DMRU results correlated with the pressure flow results for detecting UPJO. No single radiological technique predicted all initial UPJO-created kidneys that concluded with apoptosis. Further studies are required to seek with better methods for diagnosing an obstruction or to define a

  12. Constraints on mSUGRA from isospin asymmetry in $B \\to K^{*} \\gamma$

    CERN Document Server

    Mahmoudi, F

    2007-01-01

    We study the isospin asymmetry as an observable in exclusive B -> K* gamma decay that can be used to study the effects of physics beyond the Standard Model. We present predictions for isospin asymmetry in Supersymmetric extension of the Standard Model with minimal flavor violation, using parameter values allowed by current experimental constraints. This observable can provide very tight constraints on the mSUGRA parameter space.

  13. Current and future experimental strategies for structural analysis of trichothecene mycotoxins--a prospectus.

    Science.gov (United States)

    Shank, Roxanne A; Foroud, Nora A; Hazendonk, Paul; Eudes, François; Blackwell, Barbara A

    2011-12-01

    Fungal toxins, such as those produced by members of the order Hypocreales, have widespread effects on cereal crops, resulting in yield losses and the potential for severe disease and mortality in humans and livestock. Among the most toxic are the trichothecenes. Trichothecenes have various detrimental effects on eukaryotic cells including an interference with protein production and the disruption of nucleic acid synthesis. However, these toxins can have a wide range of toxicity depending on the system. Major differences in the phytotoxicity and cytotoxicity of these mycotoxins are observed for individual members of the class, and variations in toxicity are observed among different species for each individual compound. Furthermore, while diverse toxicological effects are observed throughout the whole cellular system upon trichothecene exposure, the mechanism of toxicity is not well understood. In order to comprehend how these toxins interact with the cell, we must first have an advanced understanding of their structure and dynamics. The structural analysis of trichothecenes was a subject of major interest in the 1980s, and primarily focused on crystallographic and solution-state Nuclear Magnetic Resonance (NMR) spectroscopic studies. Recent advances in structural determination through solution- and solid-state NMR, as well as computation based molecular modeling is leading to a resurgent interest in the structure of these and other mycotoxins, with the focus shifting in the direction of structural dynamics. The purpose of this work is to first provide a brief overview of the structural data available on trichothecenes and a characterization of the methods commonly employed to obtain such information. A summary of the current understanding of the relationship between structure and known function of these compounds is also presented. Finally, a prospectus on the application of new emerging structural methods on these and other related systems is discussed.

  14. Current and Future Experimental Strategies for Structural Analysis of Trichothecene Mycotoxins—A Prospectus

    Directory of Open Access Journals (Sweden)

    Barbara A. Blackwell

    2011-12-01

    Full Text Available Fungal toxins, such as those produced by members of the order Hypocreales, have widespread effects on cereal crops, resulting in yield losses and the potential for severe disease and mortality in humans and livestock. Among the most toxic are the trichothecenes. Trichothecenes have various detrimental effects on eukaryotic cells including an interference with protein production and the disruption of nucleic acid synthesis. However, these toxins can have a wide range of toxicity depending on the system. Major differences in the phytotoxicity and cytotoxicity of these mycotoxins are observed for individual members of the class, and variations in toxicity are observed among different species for each individual compound. Furthermore, while diverse toxicological effects are observed throughout the whole cellular system upon trichothecene exposure, the mechanism of toxicity is not well understood. In order to comprehend how these toxins interact with the cell, we must first have an advanced understanding of their structure and dynamics. The structural analysis of trichothecenes was a subject of major interest in the 1980s, and primarily focused on crystallographic and solution-state Nuclear Magnetic Resonance (NMR spectroscopic studies. Recent advances in structural determination through solution- and solid-state NMR, as well as computation based molecular modeling is leading to a resurgent interest in the structure of these and other mycotoxins, with the focus shifting in the direction of structural dynamics. The purpose of this work is to first provide a brief overview of the structural data available on trichothecenes and a characterization of the methods commonly employed to obtain such information. A summary of the current understanding of the relationship between structure and known function of these compounds is also presented. Finally, a prospectus on the application of new emerging structural methods on these and other related systems is

  15. Formal Verification under Unknown Constraints

    Institute of Scientific and Technical Information of China (English)

    LI Guang-hui; LI Xiao-wei

    2005-01-01

    We present a formal method of verifying designs with unknown constraints (e. g. , black boxes) using Boolean satisfiability (SAT). This method is based on a new encoding scheme of unknown constraints, and solves the corresponding conjunctive normal form (CNF) formulas. Furthermore, this method can avoid the potential memory explosion, which the binary decision diagram (BDD) based techniques maybe suffer from, thus it has the capacity of verifying large designs. Experimental results demonstrate the efficiency and feasibility of the proposed method.

  16. Nurse Scheduling System based on Dynamic Weighted Maximal Constraint Satisfaction Problem

    Science.gov (United States)

    Hattori, Hiromitsu; Isomura, Atsushi; Ito, Takayuki; Ozono, Tadachika; Shintani, Toramatsu

    Scheduling has been an important research field in Artificial Intelligence. Because typical scheduling problems could be modeled as a Constraint Satisfaction Problem(CSP), several constraint satisfaction techniques have been proposed. In order to handle the different levels of importance of the constraints, solving a problem as a Weighted Maximal Constraint Satisfaction Problem(W-MaxCSP) is an promising approach. However, there exists the case where unexpected events are added and some sudden changes are required, i.e., the case with dynamic changes in scheduling problems. In this paper, we describe such dynamic scheduling problem as a Dynamic Weighted Maximal Constraint Satisfaction Problem(DW-MaxCSP) in which constraints would changes dynamically. Generally, it is undesirable to determine vastly modified schedule even if re-scheduling is needed. A new schedule should be close to the current one as much as possible. In order to obtain stable solutions, we propose the methodology to maintain portions of the current schedule using the provisional soft constraints, which explicitly penalize the changes from the current schedule. We have experimentally confirmed the efficacy of re-scheduling based on our method with provisional constraints. In this paper, we construct the nurse scheduling system for applying the proposed scheduling method.

  17. Are current disease-modifying therapeutics in multiple sclerosis justified on the basis of studies in experimental autoimmune encephalomyelitis?

    Science.gov (United States)

    Farooqi, Nasr; Gran, Bruno; Constantinescu, Cris S

    2010-11-01

    The precise aetio-pathology of multiple sclerosis remains elusive. However, important recent advances have been made and several therapies have been licensed for clinical use. Many of these were developed, validated or tested in the animal model, experimental autoimmune encephalomyelitis (EAE). This systematic review aims to assess whether the current disease modifying treatments and those that are the closest to the clinic are justified on the basis of the results of EAE studies. We discuss some aspects of the utility and caveats of EAE as a model for multiple sclerosis drug development.

  18. Complementary numerical–experimental benchmarking for shape optimization and validation of structures subjected to wave and current forces

    DEFF Research Database (Denmark)

    Markus, D.; Ferri, Francesco; Wüchner, R.

    2015-01-01

    that focuses on differences in load curves resulting from 2D and 3D flows. It is shown that the major trends predicted by the numerical simulations are also captured in the experiment, highlighting the potential of CFD as a powerful tool for shape optimization studies. The overall aim of the paper...... variations of the structure on the resulting horizontal forces. Steady current conditions, dynamic loading due to waves, and combined wave–current scenarios are considered. A clear focus is put on simplicity and reproducibility, allowing for efficient testing of related methods and codes. This is achieved...... by defining a simple test geometry, altered in one design variable only, and by designing the test case such that a two dimensional analysis of the flow fields is possible. The force sensitivities to changes in the geometry are determined both numerically and experimentally for a great bandwidth of different...

  19. Analytical magnetic torque calculations and experimental testing of radial flux permanent magnet-type eddy current brakes

    Science.gov (United States)

    Choi, Jang-Young; Jang, Seok-Myeong

    2012-04-01

    This paper reports on analytical magnetic torque calculations and experimental tests of a radial flux permanent magnet (RFPM)-type eddy current brake (ECB). Analytical solutions for permanent magnet-generated magnetic fields that consider the eddy current reaction are obtained by using a magnetic vector potential and a two dimensional (2D) polar coordinate system. On the basis of these solutions, the analytical expressions for a magnetic torque are also derived. All analytical results are validated extensively by non-linear finite element calculations. In particular, magnetic torque measurements are obtained in tests to confirm the analyses. Finally, practical issues related to the analytical study of RFPM-type ECBs are fully discussed.

  20. They see a rat, we seek a cure for diseases: the current status of animal experimentation in medical practice.

    Science.gov (United States)

    Kehinde, Elijah O

    2013-01-01

    The objective of this review article was to examine current and prospective developments in the scientific use of laboratory animals, and to find out whether or not there are still valid scientific benefits of and justification for animal experimentation. The PubMed and Web of Science databases were searched using the following key words: animal models, basic research, pharmaceutical research, toxicity testing, experimental surgery, surgical simulation, ethics, animal welfare, benign, malignant diseases. Important relevant reviews, original articles and references from 1970 to 2012 were reviewed for data on the use of experimental animals in the study of diseases. The use of laboratory animals in scientific research continues to generate intense public debate. Their use can be justified today in the following areas of research: basic scientific research, use of animals as models for human diseases, pharmaceutical research and development, toxicity testing and teaching of new surgical techniques. This is because there are inherent limitations in the use of alternatives such as in vitro studies, human clinical trials or computer simulation. However, there are problems of transferability of results obtained from animal research to humans. Efforts are on-going to find suitable alternatives to animal experimentation like cell and tissue culture and computer simulation. For the foreseeable future, it would appear that to enable scientists to have a more precise understanding of human disease, including its diagnosis, prognosis and therapeutic intervention, there will still be enough grounds to advocate animal experimentation. However, efforts must continue to minimize or eliminate the need for animal testing in scientific research as soon as possible. © 2013 S. Karger AG, Basel.

  1. Monitoring tooth profile faults in epicyclic gearboxes using synchronously averaged motor currents: Mathematical modeling and experimental validation

    Science.gov (United States)

    Ottewill, J. R.; Ruszczyk, A.; Broda, D.

    2017-02-01

    Time-varying transmission paths and inaccessibility can increase the difficulty in both acquiring and processing vibration signals for the purpose of monitoring epicyclic gearboxes. Recent work has shown that the synchronous signal averaging approach may be applied to measured motor currents in order to diagnose tooth faults in parallel shaft gearboxes. In this paper we further develop the approach, so that it may also be applied to monitor tooth faults in epicyclic gearboxes. A low-degree-of-freedom model of an epicyclic gearbox which incorporates the possibility of simulating tooth faults, as well as any subsequent tooth contact loss due to these faults, is introduced. By combining this model with a simple space-phasor model of an induction motor it is possible to show that, in theory, tooth faults in epicyclic gearboxes may be identified from motor currents. Applying the synchronous averaging approach to experimentally recorded motor currents and angular displacements recorded from a shaft mounted encoder, validate this finding. Comparison between experiments and theory highlight the influence of operating conditions, backlash and shaft couplings on the transient response excited in the currents by the tooth fault. The results obtained suggest that the method may be a viable alternative or complement to more traditional methods for monitoring gearboxes. However, general observations also indicate that further investigations into the sensitivity and robustness of the method would be beneficial.

  2. Constraint Specialisation in Horn Clause Verification

    DEFF Research Database (Denmark)

    Kafle, Bishoksan; Gallagher, John Patrick

    2015-01-01

    We present a method for specialising the constraints in constrained Horn clauses with respect to a goal. We use abstract interpretation to compute a model of a query-answer transformation of a given set of clauses and a goal. The effect is to propagate the constraints from the goal top......-down and propagate answer constraints bottom-up. Our approach does not unfold the clauses at all; we use the constraints from the model to compute a specialised version of each clause in the program. The approach is independent of the abstract domain and the constraints theory underlying the clauses. Experimental...

  3. Studies of challenge in lower hybrid current drive capability at high density regime in experimental advanced superconducting tokamak

    Science.gov (United States)

    Ding, B. J.; Li, M. H.; Li, Y. C.; Wang, M.; Liu, F. K.; Shan, J. F.; Li, J. G.; Wan, B. N.; Wan

    2017-02-01

    Aiming at a fusion reactor, two issues must be solved for the lower hybrid current drive (LHCD), namely good lower hybrid wave (LHW)-plasma coupling and effective current drive at high density. For this goal, efforts have been made to improve LHW-plasma coupling and current drive capability at high density in experimental advanced superconducting tokamak (EAST). LHW-plasma coupling is improved by means of local gas puffing and gas puffing from the electron side is taken as a routine way for EAST to operate with LHCD. Studies of high density experiments suggest that low recycling and high lower hybrid (LH) frequency are preferred for LHCD experiments at high density, consistent with previous results in other machines. With the combination of 2.45 GHz and 4.6 GHz LH waves, a repeatable high confinement mode plasma with maximum density up to 19~\\text{m}-3$ was obtained by LHCD in EAST. In addition, in the first stage of LHCD cyclic operation, an alternative candidate for more economical fusion reactors has been demonstrated in EAST and further work will be continued.

  4. Individual cortical current density reconstructions of the semantic N400 effect: using a generalized minimum norm model with different constraints (L1 and L2 norm).

    Science.gov (United States)

    Haan, H; Streb, J; Bien, S; Rösler, F

    2000-11-01

    Event-related brain potentials were recorded to study whether verbs and nouns activate topographically distinct cortical generators. Fifteen subjects performed a primed lexical decision task with verb/verb and noun/noun pairs. The relatedness between prime and target items was varied in three steps (unrelated, moderately, and strongly related) and the EEG was recorded from 124 scalp electrodes. The topography of cortical sources of the N400 effect was evaluated by standardized differences scores and by cortical current source estimates which were constrained by the individual MRI-determined cortex anatomy. A behavioral priming effect and a substantial N400 effect was found for both word categories. However, the topography of the grand average N400 effect of verbs and nouns did not differ, neither for raw nor for standardized amplitudes. Cortical current source estimates of the N400 effect revealed a very broad and scattered distribution of active locations with pronounced interindividual differences. Cortical current source estimates obtained with the L1-norm and L2-norm model, respectively, differed in the distribution of sources over the cortex but converged on the same "hot spots." The data give no indication that the N400 effect is generated by word category-specific networks which have a different topography. The marked individual differences are discussed with respect to the involved processes and the current source estimation procedures.

  5. Recent experimental results of effects of perfluoroalkyl substances in laboratory animals - Relation to current regulations and guidance values.

    Science.gov (United States)

    Lilienthal, Hellmuth; Dieter, Hermann H; Hölzer, Jürgen; Wilhelm, Michael

    2017-03-02

    The detection of perfluoroalkyl substances (PFAS) in surface and drinking water from various countries raised the attention to the presence of these chemicals in environmental probes and led to several regulatory actions to limit exposure in human beings. There was particular concern about perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), due to their former wide-spread use. Recently, several institutions published revisions of former regulatory or recommended maximum concentrations in drinking water and food, which are markedly lower than the former values. The present short overview describes the current regulations for PFAS and compares them with the outcome of several experimental studies in laboratory animals at low-level exposure to PFOA and PFOS. In addition, regulations for short-chain PFAS are presented which, due to lack of toxicological information, are evaluated according to the concepts of Threshold of Toxicological Concern (TTC) or the Health-related Indication Values (HRIV).

  6. An experimental investigation of the dynamics of submarine leveed channel initiation as sediment-laden density currents experience sudden unconfinement

    Energy Technology Data Exchange (ETDEWEB)

    Rowland, Joel C [Los Alamos National Laboratory; Hilley, George E [STANFORD UNIV; Fildani, Andrea [CHEVRON ETC

    2009-01-01

    Leveed submarine channels play a critical role in the transfer of sediment from the upper continental slopes to interslope basins and ultimately deepwater settings. Despite a reasonable understanding of how these channels grow once established, how such channels initiate on previously unchannelized portions of the seafloor remains poorly understood. We conducted a series of experiments that elucidate the influence of excess density relative to flow velocity on the dynamics of, and depositional morphologies arising from, density currents undergoing sudden unconfinement across a sloped bed. Experimental currents transported only suspended sediment across a non-erodible substrate. Under flow conditions ranging from supercritical to subcritical (bulk Richardson numbers of 0.02 to 1.2) our experiments failed to produce deposits resembling or exhibiting the potential to evolve into self-formed leveed channels. In the absence of excess density, a submerged sediment-laden flow produced sharp crested lateral deposits bounding the margins of the flow for approximately a distance of two outlet widths down basin. These lateral deposits terminated in a centerline deposit that greatly exceeded marginal deposits in thickness. As excess density increased relative to the outlet velocity, the rate of lateral spreading of the flow increased relative to the downstream propagation of the density current, transitioning from a narrow flow aligned with the channel outlet to a broad radially expanding flow. Coincident with these changes in flow dynamics, the bounding lateral deposits extended for shorter distances, had lower, more poorly defined crests that were increasingly wider in separation than the initial outlet, and progressively became more oblong rather than linear. Based on our results, we conclude that leveed channels cannot initiate from sediment-laden density currents under strictly depositional conditions. Partial confinement of these currents appears to be necessary to

  7. Experimental Investigation of an Automobile Air-Conditioning System using Integrated Brushless Direct Current Motor Rotary Compressor

    Directory of Open Access Journals (Sweden)

    Sukri M.F.

    2016-01-01

    Full Text Available The present study presents an experimental investigation on the effect of condenser air inlet temperature and dimensionless parameter of X on the performance of automobile air-conditioning (AAC system using integrated brushless direct current motor-rotary compressor and electronic expansion valve. The other components of AAC system are from original component of AAC system used for medium size passenger car. The experimental results showed that the increment of the condenser air inlet temperature and X caused an increase in condensing temperature, cooling capacity and compressor work, while decreasing the coefficient of performance (COP. Meanwhile, the evaporating temperature increase with the increment of condenser air inlet temperature, but decrease with decrement of X. In general, AAC system have to work at higher value of X in order to produce more cooling capacity, thereby increment in compressor work also occurs due to energy balance. However, at higher value of X, the COP of the system dropped due to dominant increase in compressor power, as opposed to a rise in cooling capacity. Due to this reason, the best operation of this compressor occurs at X = 4.96 for constant T5 (35ºC, or at T5 = 30ºC for constant X (4.96.

  8. Constraint solving for direct manipulation of features

    NARCIS (Netherlands)

    Lourenco, D.; Oliveira, P.; Noort, A.; Bidarra, R.

    2006-01-01

    In current commercial feature modeling systems, support for direct manipulation of features is not commonly available. This is partly due to the strong reliance of such systems on constraints, but also to the lack of speed of current constraint solvers. In this paper, an approach to the optimization

  9. Experimental primates and non-human primate (NHP) models of human diseases in China: current status and progress.

    Science.gov (United States)

    Zhang, Xiao-Liang; Pang, Wei; Hu, Xin-Tian; Li, Jia-Li; Yao, Yong-Gang; Zheng, Yong-Tang

    2014-11-18

    Non-human primates (NHPs) are phylogenetically close to humans, with many similarities in terms of physiology, anatomy, immunology, as well as neurology, all of which make them excellent experimental models for biomedical research. Compared with developed countries in America and Europe, China has relatively rich primate resources and has continually aimed to develop NHPs resources. Currently, China is a leading producer and a major supplier of NHPs on the international market. However, there are some deficiencies in feeding and management that have hampered China's growth in NHP research and materials. Nonetheless, China has recently established a number of primate animal models for human diseases and achieved marked scientific progress on infectious diseases, cardiovascular diseases, endocrine diseases, reproductive diseases, neurological diseases, and ophthalmic diseases, etc. Advances in these fields via NHP models will undoubtedly further promote the development of China's life sciences and pharmaceutical industry, and enhance China's position as a leader in NHP research. This review covers the current status of NHPs in China and other areas, highlighting the latest developments in disease models using NHPs, as well as outlining basic problems and proposing effective countermeasures to better utilize NHP resources and further foster NHP research in China.

  10. Experimental Results of a DC Bus Voltage Level Control for a Load-Controlled Marine Current Energy Converter

    Directory of Open Access Journals (Sweden)

    Johan Forslund

    2015-05-01

    Full Text Available This paper investigates three load control methods for a  marine current energy converter using a vertical axis current  turbine (VACT mounted on a permanent magnet synchronous generator  (PMSG. The three cases are; a fixed AC load, a fixed pulse width  modulated (PWM DC load and DC bus voltage control of a DC  load. Experimental results show that the DC bus voltage control  reduces the variations of rotational speed by a factor of 3.5 at the cost  of slightly increased losses in the generator and transmission lines.  For all three cases, the tip speed ratio \\(\\lambda\\ can be kept close to  the expected \\(\\lambda_{opt}\\. The power coefficient is estimated to be  0.36 at \\(\\lambda_{opt}\\; however, for all three cases, the average  extracted power was about \\(\\sim 19\\\\%. A maximum power point  tracking (MPPT system, with or without water velocity measurement,  could increase the average extracted power.

  11. An Introduction to 'Creativity Constraints'

    DEFF Research Database (Denmark)

    Onarheim, Balder; Biskjaer, Michael Mose

    Constraints play a vital role as both restrainers and enablers in innovation processes by governing what the creative agent/s can and cannot do, and what the output can and cannot be. Notions of constraints are common in creativity research, but current contributions are highly dispersed due...... to no overall conceptual framing or shared terminology. This lack of unity hinders overt opportunities for cross-disciplinary interchange. We argue that an improved understanding of constraints in creativity holds a promising potential for advancements in creativity research across domains and disciplines. Here......, we give an overview of the growing, but incohesive body of research into creativity and constraints, which leads us to introduce ‘creativity constraints’ as a unifying concept to help bridge these disjoint contributions to facilitate cross- disciplinary interchange. Finally, we suggest key topics...

  12. Effects of constraint-induced movement therapy in children with hemiplegia: a single case experimental study Efeitos da terapia de restrição por movimento induzido em crianças com hemiplegia: desenho experimental de caso único

    Directory of Open Access Journals (Sweden)

    Marina B. Brandão

    2009-12-01

    Full Text Available OBJECTIVE: To investigate the profile of changes in the use of the upper extremity in three children with hemiplegia submitted to an adapted protocol of constraint-induced movement therapy (CIMT. METHODS: A single-subject design (ABA was replicated in three children aged 8 to 11 years old. Baseline phases (A1 and (A2 and the intervention phase (B lasted 2 weeks each. During the intervention period, children wore a splint on the non-affected extremity for 10 hours a day and were submitted to 3 hours of therapy a day during 10 days. Training consisted of activities with the affected upper extremity, with gradually increasing complexity and verbal feedback. Hand function was classified according to the Manual Ability Classification System (MACS. Children were assessed four times every week with the Toddler Arm Use Test (TAUT and three adapted tasks from the Jebsen-Taylor Hand Function test (JTHF, and once a week with the Pediatric Motor Activity Log (PMAL and self-care scales of the Pediatric Evaluation of Disability Inventory (PEDI. Celeration Line, Two-Standard Deviation Band and visual analysis methods were used for data analyses. RESULTS: Significant improvements in the amount and quality of upper extremity use (PMAL, TAUT quality of use for children 2 and 3, and participation for child 1, as well as decreased time to complete JTHF tasks for children 2 and 3 were observed. No changes were observed in the PEDI self-care scales. CONCLUSION: CIMT effects were associated with improvements in manual dexterity, amount and quality of use of the affected upper extremity in children with hemiplegia.OBJETIVO: Investigar mudanças longitudinais no uso da extremidade superior em três crianças com hemiplegia submetidas a um protocolo adaptado de terapia de movimento induzido por restrição (CIMT. MÉTODOS: Um desenho experimental de caso único (ABA foi replicado em três crianças entre 8 e 11 anos de idade. Fases de baseline (A1 e (A2 e fase de

  13. Experimental Constraints on Mantle Heterogeneity and Mantle-Melt Equilibration Depths along the Volcanic Front of the Trans-Mexican Volcanic Belt

    Science.gov (United States)

    Weaver, S.; Wallace, P. J.; Johnston, A.

    2012-12-01

    Primitive magmas erupted along the volcanic front in the Trans-Mexican Volcanic Belt (TMVB) span a wide geochemical range, with variations in silica, alkalies, and volatiles, indicating that the subarc mantle wedge is chemically heterogeneous. In this work we present the results of hydrous, near-liquidus piston-cylinder experiments for three chemically distinct primitive magmas that have erupted at the volcanic front along the TMVB. The experiments were aimed to constrain the mineralogy of equilibrium residues and final equilibration pressures and temperatures for these primitive melts over a range of H2O contents (1.5-7 wt%). The results provide an along-arc view of primitive magma equilibration conditions beneath the volcanic front of the TMVB. The experimental starting materials included a medium-K basaltic andesite (JR-28, Jorullo, Central Mexico; Weaver et al., 2011), potassic trachybasalt (JOR-46, La Pilita, central Mexico), and an alkali basalt (AY-509, Ayutla, western Mexico). The residual mineralogy for these three compositions at upper mantle pressures was harzburgite (JR-28) and wehrlite (JOR-46 and AY-509). Experimentally constrained equilibration pressures varied from 1.4 GPa-1.8 GPa, with the lowest pressure observed in the central Mexico lavas (Jorullo and La Pilita) and the highest pressures observed for the Ayutla basalt from western Mexico. Other experimental studies on primitive Mexican lavas have produced similar mantle residues and equilibration pressures; high-Mg basaltic andesite (Pelagatos, Mexico City region; Weber et al., 2011) and primitive absarokite (Mascota, Jalisco, western Mexico; Hesse and Grove, 2003) both equilibrated with harzburgite at 1.3 GPa and 1.6 GPa, respectively. We combine all of the available experimental data with recent geodynamic models of the mantle wedge beneath the TMVB to provide a comprehensive, along-arc perspective of mantle-melt equilibrium beneath the volcanic front. There is significant experimental and

  14. Experimental constraints on the P/T conditions of high silica andesite storage preceding the 2006 eruption of Augustine Volcano, Alaska

    Science.gov (United States)

    Henton, S.; Larsen, J. F.; Traxler, N.

    2010-12-01

    We present new experimental results to constrain the P/T storage conditions of the high silica andesite (HSA) prior to the 2006 eruption of Augustine Volcano, Alaska. Augustine Volcano forms a small island located in Alaska’s Cook Inlet, approximately 180 miles southwest of Anchorage. The 2006 eruption began January 11, 2006, and evolved from an initial phase of explosive activity, through continuous and effusive phases, ending approximately mid-March 2006. Lithologies erupted indicate pervasive hybridization between high- (HSA; 62.2-63.3 wt. % SiO2) and low-silica andesite (LSA; 56.6-58.7 wt% SiO2). This study focuses on experiments using the HSA as starting material to constrain magma storage conditions, based on amphibole stability. Experiments were conducted between 100-160 MPa and 800-900 °C, utilzing H2O saturated conditions and fO2 of Re-ReO. Both lightly crushed and sintered HSA were used as starting powders, seeded respectively with 5 wt. % amphibole and a mix of 5 wt. % amphibole and 20 wt. % plagioclase. Experiments with sintered starting material tended toward a bimodal distribution of experimental phenocrysts and microlites, whilst experiments of the lightly crushed material are more phenocryst rich. Preliminary results indicate that amphibole is stable at conditions of 120-140 MPa and 820-840 °C. These pressures correspond with depths of approximately 4.6-5.4 km, which are consistent with prior magma storage models for Augustine 1986 and 2006 magmas, as well as amphiboles found in other arc andesites (e.g., Redoubt and Soufriere Hills volcanoes). Experimental amphiboles are magnesio-hornblendes, which is in keeping with the natural HSA amphiboles. Experimental and natural hornblendes are similar in composition, with the main difference being a small FeO enrichment (2-3 wt%) and MgO depletion (1-2wt%) in the experimental grains. Further work will provide a more complete assessment of amphibole stability and composition, and will be applied towards

  15. Noble gas isotopic ratios from historical lavas and fumaroles at Mount Vesuvius (southern Italy): constraints for current and future volcanic activity

    Science.gov (United States)

    Tedesco, Dario; Nagao, Keisuke; Scarsi, Paolo

    1998-12-01

    Helium, neon and argon isotope ratios have been analysed from phenocrysts of eleven lava samples belonging to the last eruptive cycle of Mount Vesuvius (1631 until 1944). The phenocrysts separates include pyroxene ( N=10) and olivine ( N=1). All phenocryst samples show similarly low gas contents (He, Ne and Ar ˜10 -10 cm 3/g). 3He/ 4He ratios, 5.3-2.11 Ra, are generally low if compared to those typical of the MORB and those of the European Subcontinental Mantle (ESCM), respectively R/ Ra 8.5±1 and 6.0-6.5. A decreasing trend is found from 1631 to 1796, while a more homogeneous set of data is obtained for more recent eruptions, as evidenced by an average R/ Ra value of 2.85. Neon ratios ( 21Ne/ 22Ne and 20Ne/ 22Ne) strongly differ from those typically found on volcanoes and suggest that a crustal component has been added in the source region to Mt. Vesuvius magmas. Argon ratios ( 40Ar/ 36Ar and 38Ar/ 36Ar) have values similar to the atmosphere and are well correlated. The low 40Ar/ 36Ar ratio (max. 302) is, however, in the range of the 40Ar/ 36Ar ratios obtained from several lava samples at other Italian volcanoes and might be considered to have a deep origin. Two hypothesis have been discussed: (1) a deep argon-like-air source, due to subduction of air-rich sediments and/or (2) a preferential loss of Ar, in comparison to lighter noble gases, from silicic melts. Helium isotopic analysis of gas samples recently collected from crater and submarine fumaroles are similar to those of lavas belonging to the final part of this eruptive cycle. This result supports the idea that no new juvenile fluids from the source region have been injected into the magmatic reservoir during the 1631-1944 eruptive cycle and, more importantly, until 1993. Both sets of data help to understand the genesis of these fluids and to constrain the current activity of the volcano.

  16. Stochastic Constraint Programming

    OpenAIRE

    Walsh, Toby

    2009-01-01

    To model combinatorial decision problems involving uncertainty and probability, we introduce stochastic constraint programming. Stochastic constraint programs contain both decision variables (which we can set) and stochastic variables (which follow a probability distribution). They combine together the best features of traditional constraint satisfaction, stochastic integer programming, and stochastic satisfiability. We give a semantics for stochastic constraint programs, and propose a number...

  17. Experimental infection of the digeneans to some congeneric snail species radiated in a single water system: Relative importance of local evolution and phylogenetic constraint.

    Science.gov (United States)

    Urabe, Misako

    2016-06-01

    To determine the relative importance of local adaptation caused by host-parasite coevolution and resource tracking by the parasites, the susceptibility of the freshwater snail genus Semisulcospira to the digenean parasite genus Genarchopsis was investigated experimentally. Four snail species endemic to the Lake Biwa system in Japan and two non-endemic species were investigated. All but one species was also tested for local variation in susceptibility. Parasites were obtained from Takashima (mix population of Genarchopsis gigi and Genarchopsis chubuensis) and Nagahama (G. chubuensis). In endemic Semisulcospira, closely related specie pairs (Semisulcospira habei and Semisulcospira niponica, Semisulcospira decipiens and Semisulcospira nakasekoae) showed similar susceptibilities to parasites from both localities. S. habei and S. niponica were highly susceptible to parasites from Takashima, but were resistant to parasites from Nagahama. S. decipiens and S. nakasekoae showed moderate susceptibility to parasites from both localities. None of the endemic snail species showed a clear local variation in susceptibility. These results show that the susceptibility of endemic Semisulcospira to Genarchopsis is conservative and can be regarded as an example of resource-tracking. One of the non-endemic snails, Semisulcospira libertina, showed local variation in susceptibility. This variation was not related to the sympatry of the parasites used for the experimental infection, suggesting that it was not the result of local adaptation by parasites.

  18. Reactivity of organic-rich sediment in seawater at 350°c, 500 bars: experimental and theoretical constraints and implications for the guaymas basin hydrothermal system

    Science.gov (United States)

    Thornton, Edward C.; Seyfried, W. E., Jr.

    1987-07-01

    Hydrothermal alteration of organic-rich diatomaceous sediment by seawater was modelled experimentally at 350°C, 500 bars and seawater/sediment mass ratio of 3. The experiment was performed to assess the effect of organic matter reactivity on solution speciation and sediment alteration processes at an elevated temperature and pressure and provide requisite data to better understand the chemistry of hydrothermal fluids issuing from vents in the Guaymas Basin, Gulf of California. Seawater chemistry changed greatly during the experiment. In particular, Na, Mg and SO 4 decreased, while ∑ CO 2, ∑ NH 3, ∑ H 2S, SiO 2, Ca, K, H 2, CH 4 and heavy and base metals increased. Moreover, owing to the thermal alteration of sediment organic matter, organic acids, phenolic derivatives and phthlate were released to solution. Examination of solid alteration products revealed the effects of extensive dissolution and precipitation processes characterized by total elimination of diatoms and formation of cristobalite, quartz (?), pyrite, pyrrhotite, mixed layer chlorite/smectite and calcite. Plagioclase feldspar (An 40) recrystallized to a more albitic form owing to Na fixation and Ca cycling to calcite. A graphitic residue was also present in the products of the experiment. Mg and Na fixation reactions during the experiment generated significant H +, although the pH measured at 25°C was approximately 6.2. SO 4 reduction and thermal alteration and dissolution of organics, however, consume H + and are chiefly responsible for the near neutral pH for the overall reaction. Speciation calculations including ammine and acetate protonation reactions give a pH at experimental conditions of approximately 5.1, while mineral solubility relations involving virtually all alteration phases require a pH of 5.57 to 5.94. A near neutral pH at experimental conditions constrains the mobility of Fe, Mn, Zn, Cu and Ni, which existed in solution as chloro-complexes. Dissolved concentrations of Pb and

  19. Rigidity Constraints for Large Mesh Deformation

    Institute of Scientific and Technical Information of China (English)

    Yong Zhao; Xin-Guo Liu; Qun-Sheng Peng; Hu-Jun Bao

    2009-01-01

    It is a challenging problem of surface-based deformation to avoid apparent volumetric distortions around largely deformed areas. In this paper, we propose a new rigidity constraint for gradient domain mesh deformation to address this problem. Intuitively the proposed constraint can be regarded as several small cubes defined by the mesh vertices through mean value coordinates. The user interactively specifies the cubes in the regions which are prone to volumetric distortions, and the rigidity constraints could make the mesh behave like a solid object during deformation. The experimental results demonstrate that our constraint is intuitive, easy to use and very effective.

  20. Observational constraints on cluster evolution

    NARCIS (Netherlands)

    Larsen, S.S.|info:eu-repo/dai/nl/304833347

    2008-01-01

    Current observational constraints on the dynamical evolution of star clusters are reviewed. Theory and observations now agree nicely on the mass dependency and time scales for disruption of young star clusters in galactic disks, but many problems still await resolution. The origin of the mass

  1. Experimental constraints on the γ-ray strength function in 90Zr using partial cross sections of the Y89(p,γZr90 reaction

    Directory of Open Access Journals (Sweden)

    L. Netterdon

    2015-05-01

    Full Text Available Partial cross sections of the Y89(p,γZr90 reaction have been measured to investigate the γ-ray strength function in the neutron–magic nucleus 90Zr. For five proton energies between Ep=3.65 MeV and Ep=4.70 MeV, partial cross sections for the population of seven discrete states in 90Zr have been determined by means of in-beam γ-ray spectroscopy. Since these γ-ray transitions are dominantly of E1 character, the present measurement allows an access to the low-lying dipole strength in 90Zr. A γ-ray strength function based on the experimental data could be extracted, which is used to describe the total and partial cross sections of this reaction by Hauser–Feshbach calculations successfully. Significant differences with respect to previously measured strength functions from photoabsorption data point towards deviations from the Brink–Axel hypothesis relating the photo-excitation and de-excitation strength functions.

  2. Thermodiffusion in concentrated ferrofluids: A review and current experimental and numerical results on non-magnetic thermodiffusion

    Energy Technology Data Exchange (ETDEWEB)

    Sprenger, Lisa, E-mail: Lisa.Sprenger@tu-dresden.de; Lange, Adrian; Odenbach, Stefan [Institute of Fluid Mechanics, Chair of Magnetofluiddynamics, Measuring and Automation Technology, TU Dresden, 01062 Dresden (Germany)

    2013-12-15

    Ferrofluids are colloidal suspensions consisting of magnetic nanoparticles dispersed in a carrier liquid. Their thermodiffusive behaviour is rather strong compared to molecular binary mixtures, leading to a Soret coefficient (S{sub T}) of 0.16 K{sup −1}. Former experiments with dilute magnetic fluids have been done with thermogravitational columns or horizontal thermodiffusion cells by different research groups. Considering the horizontal thermodiffusion cell, a former analytical approach has been used to solve the phenomenological diffusion equation in one dimension assuming a constant concentration gradient over the cell's height. The current experimental work is based on the horizontal separation cell and emphasises the comparison of the concentration development in different concentrated magnetic fluids and at different temperature gradients. The ferrofluid investigated is the kerosene-based EMG905 (Ferrotec) to be compared with the APG513A (Ferrotec), both containing magnetite nanoparticles. The experiments prove that the separation process linearly depends on the temperature gradient and that a constant concentration gradient develops in the setup due to the separation. Analytical one dimensional and numerical three dimensional approaches to solve the diffusion equation are derived to be compared with the solution used so far for dilute fluids to see if formerly made assumptions also hold for higher concentrated fluids. Both, the analytical and numerical solutions, either in a phenomenological or a thermodynamic description, are able to reproduce the separation signal gained from the experiments. The Soret coefficient can then be determined to 0.184 K{sup −1} in the analytical case and 0.29 K{sup −1} in the numerical case. Former theoretical approaches for dilute magnetic fluids underestimate the strength of the separation in the case of a concentrated ferrofluid.

  3. Current Observational Constraints on Cosmic Doomsday

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yun

    2004-09-14

    In a broad class of dark energy models, the universe may collapse within a finite time t{sub c}. Here we study a representative model of dark energy with a linear potential, V({phi})=V{sub 0}(1 + {alpha}{phi}). This model is the simplest doomsday model, in which the universe collapses rather quickly after it stops expanding. Observational data from type Ia supernovae (SNe Ia), cosmic microwave background anisotropy (CMB), and large scale structure (LSS) are complementary in constraining dark energy models. Using the new SN Ia data (Riess sample), the CMB data from WMAP, and the LSS data from 2dF, we find that the collapse time of the universe is t{sub c} {approx}> 42 (24) gigayears from today at 68% (95%) confidence.

  4. The Current State of Knowledge of Hepatic Ischemia-Reperfusion Injury Based on Its Study in Experimental Models

    Science.gov (United States)

    Mendes-Braz, M.; Elias-Miró, M.; Jiménez-Castro, M. B.; Casillas-Ramírez, A.; Ramalho, F. S.; Peralta, C.

    2012-01-01

    The present review focuses on the numerous experimental models used to study the complexity of hepatic ischemia/reperfusion (I/R) injury. Although experimental models of hepatic I/R injury represent a compromise between the clinical reality and experimental simplification, the clinical transfer of experimental results is problematic because of anatomical and physiological differences and the inevitable simplification of experimental work. In this review, the strengths and limitations of the various models of hepatic I/R are discussed. Several strategies to protect the liver from I/R injury have been developed in animal models and, some of these, might find their way into clinical practice. We also attempt to highlight the fact that the mechanisms responsible for hepatic I/R injury depend on the experimental model used, and therefore the therapeutic strategies also differ according to the model used. Thus, the choice of model must therefore be adapted to the clinical question being answered. PMID:22649277

  5. Supernova constraints on neutrino mass and mixing

    Indian Academy of Sciences (India)

    Srubabati Goswami

    2000-01-01

    In this article I review the constraints on neutrino mass and mixing coming from type-II supernovae. The bounds obtained on these parameters from shock reheating, -process nucleosynthesis and from SN1987A are discussed. Given the current constraints on neutrino mass and mixing the effect of oscillations of neutrinos from a nearby supernova explosion in future detectors will also be discussed.

  6. Constrained Optimization Based on Hybrid Evolutionary Algorithm and Adaptive Constraint-Handling Technique

    DEFF Research Database (Denmark)

    Wang, Yong; Cai, Zixing; Zhou, Yuren

    2009-01-01

    A novel approach to deal with numerical and engineering constrained optimization problems, which incorporates a hybrid evolutionary algorithm and an adaptive constraint-handling technique, is presented in this paper. The hybrid evolutionary algorithm simultaneously uses simplex crossover and two...... mutation operators to generate the offspring population. Additionally, the adaptive constraint-handling technique consists of three main situations. In detail, at each situation, one constraint-handling mechanism is designed based on current population state. Experiments on 13 benchmark test functions...... and four well-known constrained design problems verify the effectiveness and efficiency of the proposed method. The experimental results show that integrating the hybrid evolutionary algorithm with the adaptive constraint-handling technique is beneficial, and the proposed method achieves competitive...

  7. Constraint-based animation: temporal constraints in the Animus systems

    Energy Technology Data Exchange (ETDEWEB)

    Duisberg, R.A.

    1986-01-01

    Algorithm animation has a growing role in computer-aided algorithm design documentation and debugging, since interactive graphics is a richer channel than text for communication. Most animation is currently done laboriously by hand, and it often has the character of canned demonstrations with restricted user interaction. Animus is a system that allows easy construction of an animation with minimal concern for lower-level graphics programming. Constraints are used to describe the appearance and structure of a picture as well as how those pictures evolve in time. The implementation and support of temporal constraints is a substantive extension to previous constraint languages which had only allowed specification of static state. Use of the Animus system is demonstrated in the creation of animations of dynamic mechanical and electrical-circuit simulations, sorting algorithms, problems in operating systems, and geometric curve-drawing algorithms.

  8. Fluid-present melting of sulfide-bearing ocean-crust: Experimental constraints on the transport of sulfur from subducting slab to mantle wedge

    Science.gov (United States)

    Jégo, Sébastien; Dasgupta, Rajdeep

    2013-06-01

    To constrain the sulfur enrichment of arc magma source-regions and the agent of sulfur transport from subducting slab to mantle wedge, here we report experimental measurements of sulfur content at sulfide saturation (SCSS) of slab-derived hydrous partial melts at 2.0 and 3.0 GPa and from 800 to 1050 °C, using Ni-NiO (NNO) and Co-CoO (CCO) external oxygen fugacity (fO2) buffers. A synthetic H2O-saturated MORB with 1 wt.% S (added as pyrite) was used as starting material. All experiments produced pyrrhotite- and fluid-saturated assemblages of silicate glass, clinopyroxene, garnet, quartz, and rutile (plus amphibole at 2 GPa/800 °C and phengite at 3 GPa/850 °C). The silicate partial melt composition evolves from rhyolitic to rhyodacitic compositions with increasing temperature and melting degree in equilibrium with an eclogitic residue, showing substantial decrease in SiO2 and Mg# and increase in FeOT, TiO2 and Na2O. At all temperatures melt sulfur concentrations are very low, with an average of 110 ± 50 ppm S, similar to previous measurements at lower pressures. Melt SCSS appears to be mainly controlled by the melt composition, the activity of water, aH2O and the sulfur fugacity, fS2 (calculated from the composition of pyrrhotite). Mass-balance calculations show that the proportion of bulk sulfur dissolved in the silicate melt is negligible (<0.005 wt.% of the bulk sulfur). In contrast, diminishing proportion of pyrrhotite with increasing temperature suggests that the fluid phase at equilibrium may contain as much as 10-15 wt.% S at ⩾1050 °C, and more than 40 wt.% of the bulk sulfur initially present in the slab may be transferred to the aqueous fluid. Our data also suggest that fluid/melt sulfur partitioning increases with increasing temperature, from ˜300 at 900 °C to ˜1200 at 1050 °C, whereas pressure appears to have less of an effect. With respect to fO2, no real difference of fluid/melt S partitioning, within data uncertainties, between NNO and CCO at

  9. Causality Constraints in Conformal Field Theory

    CERN Document Server

    CERN. Geneva

    2015-01-01

    Causality places nontrivial constraints on QFT in Lorentzian signature, for example fixing the signs of certain terms in the low energy Lagrangian. In d-dimensional conformal field theory, we show how such constraints are encoded in crossing symmetry of Euclidean correlators, and derive analogous constraints directly from the conformal bootstrap (analytically). The bootstrap setup is a Lorentzian four-point function corresponding to propagation through a shockwave. Crossing symmetry fixes the signs of certain log terms that appear in the conformal block expansion, which constrains the interactions of low-lying operators. As an application, we use the bootstrap to rederive the well known sign constraint on the (∂φ)4 coupling in effective field theory, from a dual CFT. We also find constraints on theories with higher spin conserved currents. Our analysis is restricted to scalar correlators, but we argue that similar methods should also impose nontrivial constraints on the interactions of spinni...

  10. Causality Constraints in Conformal Field Theory

    CERN Document Server

    Hartman, Thomas; Kundu, Sandipan

    2015-01-01

    Causality places nontrivial constraints on QFT in Lorentzian signature, for example fixing the signs of certain terms in the low energy Lagrangian. In d-dimensional conformal field theory, we show how such constraints are encoded in crossing symmetry of Euclidean correlators, and derive analogous constraints directly from the conformal bootstrap (analytically). The bootstrap setup is a Lorentzian four-point function corresponding to propagation through a shockwave. Crossing symmetry fixes the signs of certain log terms that appear in the conformal block expansion, which constrains the interactions of low-lying operators. As an application, we use the bootstrap to rederive the well known sign constraint on the $(\\partial\\phi)^4$ coupling in effective field theory, from a dual CFT. We also find constraints on theories with higher spin conserved currents. Our analysis is restricted to scalar correlators, but we argue that similar methods should also impose nontrivial constraints on the interactions of spinning o...

  11. Principles of applied experimental igneous petrology: A comment on “Experimental constraints on the Skaergaard liquid line of descent” by Thy, Lesher, Nielsen, and Brooks, 2006, Lithos 92: 154 180

    Science.gov (United States)

    Morse, S. A.

    2008-10-01

    The foremost principles of experimental igneous petrology applied to natural rocks are here considered to be the following. First, only the mineral assemblages found at or near the experimental liquidus are relevant to fractional crystallization. Subliquidus assemblages of the same bulk composition can have little relevance to this process, owing to the closed system of the experiment. Second, in a closed system the natural mineral assemblages define the intensive parameters of T, P, and the activities of all components, including oxygen, which must constrain the experimental investigation. Extensive (mass-dependent) parameters do not define the compositions of the evolving liquids, which are solely controlled by successive liquidus phase assemblages. Third, the bulk compositions (rocks or mixtures) chosen for study must be able to yield at the liquidus the mineral compositions found in the natural occurrence. The study under discussion fails in all three of these desiderata. Subliquidus products of equilibrium crystallization and their masses were used to infer a differentiation history. Intensive parameters were constrained to an arbitrary choice of the FMQ buffer. Finally, the bulk compositions chosen for experiment can be shown beforehand (and as in the listed results) to yield olivine and plagioclase compositions far more refractory than in any known rock of the target intrusion.

  12. The Soft Cumulative Constraint

    CERN Document Server

    Petit, Thierry

    2009-01-01

    This research report presents an extension of Cumulative of Choco constraint solver, which is useful to encode over-constrained cumulative problems. This new global constraint uses sweep and task interval violation-based algorithms.

  13. Developmental constraints on behavioural flexibility.

    Science.gov (United States)

    Holekamp, Kay E; Swanson, Eli M; Van Meter, Page E

    2013-05-19

    We suggest that variation in mammalian behavioural flexibility not accounted for by current socioecological models may be explained in part by developmental constraints. From our own work, we provide examples of constraints affecting variation in behavioural flexibility, not only among individuals, but also among species and higher taxonomic units. We first implicate organizational maternal effects of androgens in shaping individual differences in aggressive behaviour emitted by female spotted hyaenas throughout the lifespan. We then compare carnivores and primates with respect to their locomotor and craniofacial adaptations. We inquire whether antagonistic selection pressures on the skull might impose differential functional constraints on evolvability of skulls and brains in these two orders, thus ultimately affecting behavioural flexibility in each group. We suggest that, even when carnivores and primates would theoretically benefit from the same adaptations with respect to behavioural flexibility, carnivores may nevertheless exhibit less behavioural flexibility than primates because of constraints imposed by past adaptations in the morphology of the limbs and skull. Phylogenetic analysis consistent with this idea suggests greater evolutionary lability in relative brain size within families of primates than carnivores. Thus, consideration of developmental constraints may help elucidate variation in mammalian behavioural flexibility.

  14. Composing constraint solvers

    NARCIS (Netherlands)

    Zoeteweij, P.

    2005-01-01

    Composing constraint solvers based on tree search and constraint propagation through generic iteration leads to efficient and flexible constraint solvers. This was demonstrated using OpenSolver, an abstract branch-and-propagate tree search engine that supports a wide range of relevant solver configu

  15. A study into ant colony optimisation, evolutionary computation and constraint programming on binary constraint satisfaction problems.

    NARCIS (Netherlands)

    J.I. van Hemert; C. Solnon

    2004-01-01

    textabstractWe compare two heuristic approaches, evolutionary computation and ant colony optimisation, and a complete tree-search approach, constraint programming, for solving binary constraint satisfaction problems. We experimentally show that, if evolutionary computation is far from being able to

  16. Characteristics of inertial oscillations according to the experimental measurements of currents on the Russian shelf of the Black Sea

    Science.gov (United States)

    Bondur, V. G.; Sabinin, K. D.; Grebenyuk, Yu. V.

    2017-01-01

    The analysis of inertial oscillations on the Gelendzhik shelf of the Black Sea is presented. Spectral characteristics of the current fields are studied based on the measurements taken by the acoustic Doppler current profiler. Strong variability of the inertial oscillation hodographs at variations in the background shear current and diverse forms of inertial oscillations measured at a fixed point at various values of the shear current are revealed. The relation between the passage of the multidirectional jets and the trains of inertial oscillations inside the jets in the studied region are established.

  17. Experimental and numerical examination of eddy (Foucault) currents in rotating micro-coils: Generation of heat and its impact on sample temperature.

    Science.gov (United States)

    Aguiar, Pedro M; Jacquinot, Jacques-François; Sakellariou, Dimitris

    2009-09-01

    The application of nuclear magnetic resonance (NMR) to systems of limited quantity has stimulated the use of micro-coils (diameter Foucault (eddy) currents, which generate heat. We report the first data acquired with a 4mm MACS system and spinning up to 10kHz. The need to spin faster necessitates improved methods to control heating. We propose an approximate solution to calculate the power losses (heat) from the eddy currents for a solenoidal coil, in order to provide insight into the functional dependencies of Foucault currents. Experimental tests of the dependencies reveal conditions which result in reduced sample heating and negligible temperature distributions over the sample volume.

  18. On Testing Constraint Programs

    CERN Document Server

    Lazaar, Nadjib; Yahia, Lebbah

    2010-01-01

    The success of several constraint-based modeling languages such as OPL, ZINC, or COMET, appeals for better software engineering practices, particularly in the testing phase. This paper introduces a testing framework enabling automated test case generation for constraint programming. We propose a general framework of constraint program development which supposes that a first declarative and simple constraint model is available from the problem specifications analysis. Then, this model is refined using classical techniques such as constraint reformulation, surrogate and global constraint addition, or symmetry-breaking to form an improved constraint model that must be thoroughly tested before being used to address real-sized problems. We think that most of the faults are introduced in this refinement step and propose a process which takes the first declarative model as an oracle for detecting non-conformities. We derive practical test purposes from this process to generate automatically test data that exhibit no...

  19. Upgrade of the Gas Flow Control System of the Resistive Current Leads of the LHC Inner Triplet Magnets: Simulation and Experimental Validation

    CERN Document Server

    Perin, A; Casas-Cubillos, J; Pezzetti, M

    2014-01-01

    The 600 A and 120 A circuits of the inner triplet magnets of the Large Hadron Collider are powered by resistive gas cooled current leads. The current solution for controlling the gas flow of these leads has shown severe operability limitations. In order to allow a more precise and more reliable control of the cooling gas flow, new flowmeters will be installed during the first long shutdown of the LHC. Because of the high level of radiation in the area next to the current leads, the flowmeters will be installed in shielded areas located up to 50 m away from the current leads. The control valves being located next to the current leads, this configuration leads to long piping between the valves and the flowmeters. In order to determine its dynamic behaviour, the proposed system was simulated with a numerical model and validated with experimental measurements performed on a dedicated test bench.

  20. Direct Experimental Evidence for Current-Transfer Mode Operation of Nested Tungsten Wire Arrays at 16 19 MA

    Science.gov (United States)

    Cuneo, M. E.; Sinars, D. B.; Bliss, D. E.; Waisman, E. M.; Porter, J. L.; Stygar, W. A.; Lebedev, S. V.; Chittenden, J. P.; Sarkisov, G. S.; Afeyan, B. B.

    2005-06-01

    Nested tungsten wire arrays (20-mm on 12-mm diam.) are shown for the first time to operate in a current-transfer mode at 16 19 MA, even for azimuthal interwire gaps of 0.2 mm that are the smallest typically used for any array experiment. After current transfer, the inner wire array shows discrete wire ablation and implosion characteristics identical to that of a single array, such as axially nonuniform ablation, delayed acceleration, and trailing mass and current. The presence of trailing mass from the outer and the inner arrays may play a role in determining nested array performance.

  1. Experimental study of the dependence of beam current on injection magnetic field in 6.4 GHz ECR ion source

    Indian Academy of Sciences (India)

    G S Taki; P R Sarma; D K Chakraborty; R K Bhandari; P K Ray

    2006-09-01

    The ion current from an electron cyclotron resonance (ECR) heavy ion source depends on the confining axial and radial magnetic fields. Some efforts were made by earlier workers to investigate magnetic field scaling on the performance of the ECR source. In order to study the dependence of the ion current on the injection magnetic field in the 6.4 GHz ECR source, we have measured the current by varying the peak injection field and have inferred that the variation of the current is exponential up to our maximum design injection field of 7.5 kG. An attempt has been made to understand this exponential nature on the basis of ion confinement time.

  2. Design and Experimental Study of a Current Transformer with a Stacked PCB Based on B-Dot.

    Science.gov (United States)

    Wang, Jingang; Si, Diancheng; Tian, Tian; Ren, Ran

    2017-04-10

    An electronic current transformer with a B-dot sensor is proposed in this study. The B-dot sensor can realize the current measurement of the transmission line in a non-contact way in accordance with the principle of magnetic field coupling. The multiple electrodes series-opposing structure is applied together with differential input structures and active integrating circuits, which can allow the sensor to operate in differential mode. Maxwell software is adopted to model and simulate the sensor. Optimization of the sensor structural parameters is conducted through finite-element simulation. A test platform is built to conduct the steady-state characteristic, on-off operation, and linearity tests for the designed current transformer under the power-frequency current. As shown by the test results, in contrast with traditional electromagnetic CT, the designed current transformer can achieve high accuracy and good phase-frequency; its linearity is also very good at different distances from the wire. The proposed current transformer provides a new method for electricity larceny prevention and on-line monitoring of the power grid in an electric system, thereby satisfying the development demands of the smart power grid.

  3. Managing Restaurant Tables using Constraints

    Science.gov (United States)

    Vidotto, Alfio; Brown, Kenneth N.; Beck, J. Christopher

    Restaurant table management can have significant impact on both profitability and the customer experience. The core of the issue is a complex dynamic combinatorial problem. We show how to model the problem as constraint satisfaction, with extensions which generate flexible seating plans and which maintain stability when changes occur. We describe an implemented system which provides advice to users in real time. The system is currently being evaluated in a restaurant environment.

  4. Constraint Cooling of Hot Rolled Coil

    Institute of Scientific and Technical Information of China (English)

    WANG Li-juan; ZHANG Chun-li

    2004-01-01

    The layer thermal conductivity during constraint cooling of hot rolled coil was described by using equivalent thermal conductivity model and finite element method. Two radial stress concentration zones in constraint cooled coil were shown by numerical analysis, and the tension stress was assumed to be the main factor to induce stress corrosion. The experimental results show that the longer the water cooling time is, the smaller the grain size and the more uniform the grains are.

  5. Constraints meet concurrency

    CERN Document Server

    Mauro, Jacopo

    2014-01-01

    This book describes the benefits that emerge when the fields of constraint programming and concurrency meet. On the one hand, constraints can be used in concurrency theory to increase the conciseness and the expressive power of concurrent languages from a pragmatic point of view. On the other hand, problems modeled by using constraints can be solved faster and more efficiently using a concurrent system. Both directions are explored providing two separate lines of development. Firstly the expressive power of a concurrent language is studied, namely Constraint Handling Rules, that supports constraints as a primitive construct. The features of this language which make it Turing powerful are shown. Then a framework is proposed to solve constraint problems that is intended to be deployed on a concurrent system. For the development of this framework the concurrent language Jolie following the Service Oriented paradigm is used. Based on this experience, an extension to Service Oriented Languages is also proposed in ...

  6. On Minimal Constraint Networks

    CERN Document Server

    Gottlob, Georg

    2011-01-01

    In a minimal binary constraint network, every tuple of a constraint relation can be extended to a solution. It was conjectured that computing a solution to such a network is NP complete. We prove this conjecture true and show that the problem remains NP hard even in case the total domain of all values that may appear in the constraint relations is bounded by a constant.

  7. Temporal Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Valencia Posso, Frank Dan

    2002-01-01

    The ntcc calculus is a model of non-deterministic temporal concurrent constraint programming. In this paper we study behavioral notions for this calculus. In the underlying computational model, concurrent constraint processes are executed in discrete time intervals. The behavioral notions studied...... reflect the reactive interactions between concurrent constraint processes and their environment, as well as internal interactions between individual processes. Relationships between the suggested notions are studied, and they are all proved to be decidable for a substantial fragment of the calculus...

  8. Experimental investigation of the effect of titanium dioxide and barium titanate additives on DC transient currents in low density polyethylene

    DEFF Research Database (Denmark)

    Khalil, M.S; Henk, Peter O; Henriksen, Mogens

    1988-01-01

    The effect of titanium dioxide as a semiconductive additive and barium titanate as a highly polar additive on the DC transient currents in low-density polyethylene is investigated. Experiments were made using thick specimens under a high electric field (>25×106 V/m) and a constant temperature of 40...

  9. 中国玉米秸秆直接还田的现状与发展%Development of Direct Return of Corn Stalk to Soil:Current Status, Driving Forces and Constraints

    Institute of Scientific and Technical Information of China (English)

    吕开宇; 仇焕广; 白军飞; 徐志刚

    2013-01-01

    推广秸秆还田对于改善土壤条件、促进农业可持续发展意义重大.但与美国等发达国家相比,我国玉米秸秆直接还田比例仍较低,地域差异明显.本文旨在从技术和经济两个方面,掌握玉米秸秆直接还田的现状,理清未来推广的重点和思路.为此,采用实地调查、文献资料查阅和专家访谈等研究方法,首先利用技术参数对我国玉米秸秆的资源总量及其使用结构进行估计,从总体上把握玉米秸秆的资源状况和还田发展水平;其次依据文献和调研信息,从积极和消极两个方面系统分析了玉米秸秆直接还田技术应用的经济环境影响,从技术和经济两个角度分析了现阶段推广该技术面临的主要瓶颈;再次结合美国推广的成功经验,论证了我国未来推广玉米秸秆直接还田技术的可行性,并明确了未来推广的关键;最后从政策、技术、舆论和调研四个方面提出了政策建议.%The direct return of corn stalk to soil can significantly contribute to the improvement of soil fertility and the sustainable development of agriculture. Comparing to the status quo in many developed countries like the U. S. , the return rate of corn stalk in China is still at a lower level with obvious regional discrepancy. This paper aims to understand the current status of direct return of corn stalk to soil and to identify the main constrains and strategies for the development of such tillage technology from both the technical and economic perspectives. To achieve these objectives, methods such as field survey, literature review and expert interview were employed. First, the paper estimates the amount and utilization of corn stalk resources in China by using relative technical conversion parameters to understand the potentials and use of corn stalks in China. Second, this paper analyzes the positive and negative effects of practices of direct return of corn stalk to soil on local agricultural

  10. RESULTS OF CALCULATION-EXPERIMENTAL INVESTIGATIONS OF ELECTRO-THERMAL RESISTIBILITY OF SHEET STEEL SAMPLES TO ACTION OF RATIONED COMPONENTS OF PULSED CURRENT OF ARTIFICIAL LIGHTING

    Directory of Open Access Journals (Sweden)

    M.I. Baranov

    2016-06-01

    Full Text Available Purpose. Calculation and experimental researches of the electro-thermal resistibility of the steel sheet samples to action standard pulse current components of the artificial lightning with amplitude-time parameters (ATP, corresponded the requirements of normative documents of USA for SAE ARP 5412 & SAE ARP 5416. Methodology. Electrophysics bases of technique of high tensions and large impulsive currents (LIC, and also scientific and technical bases of planning of devices of high-voltage impulsive technique and measuring in them LIC. Сurrent amplitude ImA=±200 kA (with a tolerance of ±10 %; current action integral JA=2∙106 A2•s (with a tolerance of ±20 %; time, corresponding to the amplitude of the current ImA, tmA≤50 microseconds; the duration of the current flow τpA≤500 microseconds. Results. The results of the evaluation of the calculated and experimental studies of electro-thermal resistance of the samples of plates measuring 0,5 m  0,5 m stainless steel 1 mm thickness to the action on them artificial lightning impulse currents with rationed ATP on the requirements of normative documents of USA for SAE ARP 5412 & SAE ARP 5416. A pulse A- component have a first amplitude 192 kA, the corresponding time of 34 μs, and the duration aperiodic component amplitude 804 A, corresponding to the time 9 ms. It has been shown that the long C- component current of artificial lightning can lead to keyhole these samples. The diameter of the holes in this thin steel sheet, which is formed during the flow of current C- components can reach 15 mm. The results of calculation and experiment agree within 28 %. Originality. For the first time in world practice on the generator large pulsed currents experimental studies of resistibility of sheet steel samples to the action of artificial lightning currents with critical parameters. Practical value. Using the results obtained in the practice of lightning protection will significantly improve the

  11. Induced current and redefinition of electric and magnetic fields from non-compact Kaluza-Klein theory: An experimental signature of the fifth dimension

    CERN Document Server

    Liko, T

    2005-01-01

    The field equations for gravitation and electromagnetism with sources in four dimensions can be interpreted as arising from the vacuum Einstein equations in five dimensions. Gauge invariance of the electromagnetic potentials leads to a ``generalized'' electromagnetic field tensor. We use the action principle to derive the equations of motion for free electromagnetic fields in flat spacetime, and isolate an effective electromagnetic current with a source that is purely higher-dimensional in origin. This current provides, at least in principle, a means of detecting extra dimensions experimentally.

  12. Theoretical and experimental study of superradiance pulse generation by heavy-current subnanosecond electron bunches moving in periodic slowing down system

    CERN Document Server

    Ginzburg, N S; Novozhilova, Y V; Sergeev, A S; Shpak, V G; Shunailov, S A; Ul'maskulov, M R; Yalandin, M I

    2002-01-01

    One studied both theoretically and experimentally the Cherenkov superradiance at liner motion of an electron bunch through the periodic slowing down system. Simulations in terms of the KARAT code show that peak intensity of microwave pulses is proportional to the square of total number of particles in a bunch. This finding os conformed experimentally. As a results, at 39 GHz frequency one obtained ultrashort pulses of up to 140 MW high intensity and with 30 ps duration. The RADAN 303 high-current subnanosecond accelerator injected electron bunches with up to 2 A current, 0.5-1.5 ns duration and 200-300 keV particle energy was used as a source of electrons. Simulation shows possibility of further intensification of electromagnetic pulses up to 300-400 MW due to optimization of parameters of accelerating voltage pulse

  13. Design of an Experimental Contemporary Physics Course which Develops the Full Experience of Scientific Research and Highlights Current Faculty Research

    Science.gov (United States)

    Yarrison-Rice, Jan M.; Jaeger, Herbert; Eid, Khalid F.

    2013-03-01

    From background literature searches and reading, to conducting experiments, to presenting results and writing a journal manuscript, Miami University has revised its second-year Experimental Contemporary Physics Course, Phy293, to follow a basic research model. We examined research that faculty were conducting and chose experiments which were strongly related to understanding the ongoing research in the Department, while being based in fundamental quantum mechanics and recent 21st century physics. Experiments often had common instrumentation and data analysis techniques which allowed for grouping them into 3 basic categories: 1) Spectroscopy of gases and solids, 2) Characterization of contemporary samples, and 3) Quantized systems in electronic, magnetic and nuclear physics. These experiments also supported our secondary goal of preparing students to enter our research laboratories. At Miami, we generally have between 25-35 second year students, so the laboratory course must be managed to maintain groups of 2-3 for the best student learning outcomes. We will report on course logistics, the grouping of experiments, and methods for assessing students' learning. Having run the revised, full experimental format of Phy293 a 3rd time, we feel confident stating that this course demonstrates to students ``how physics research in the 21st century is actually conducted!''

  14. Decrease of a Current Mediated by Kv1.3 Channels Causes Striatal Cholinergic Interneuron Hyperexcitability in Experimental Parkinsonism

    Directory of Open Access Journals (Sweden)

    Cecilia Tubert

    2016-09-01

    Full Text Available The mechanism underlying a hypercholinergic state in Parkinson’s disease (PD remains uncertain. Here, we show that disruption of the Kv1 channel-mediated function causes hyperexcitability of striatal cholinergic interneurons in a mouse model of PD. Specifically, our data reveal that Kv1 channels containing Kv1.3 subunits contribute significantly to the orphan potassium current known as IsAHP in striatal cholinergic interneurons. Typically, this Kv1 current provides negative feedback to depolarization that limits burst firing and slows the tonic activity of cholinergic interneurons. However, such inhibitory control of cholinergic interneuron excitability by Kv1.3-mediated current is markedly diminished in the parkinsonian striatum, suggesting that targeting Kv1.3 subunits and their regulatory pathways may have therapeutic potential in PD therapy. These studies reveal unexpected roles of Kv1.3 subunit-containing channels in the regulation of firing patterns of striatal cholinergic interneurons, which were thought to be largely dependent on KCa channels.

  15. Numerical and Experimental Study of the 3D Effect on Connecting Arm of Vertical Axis Tidal Current Turbine

    Institute of Scientific and Technical Information of China (English)

    郭伟; 康海贵; 陈兵; 谢宇; 王胤

    2016-01-01

    Vertical axis tidal current turbine is a promising device to extract energy from ocean current. One of the important components of the turbine is the connecting arm, which can bring about a significant effect on the pressure distribution along the span of the turbine blade, herein we call it 3D effect. However, so far the effect is rarely reported in the research, moreover, in numerical simulation. In the present study, a 3D numerical model of the turbine with the connecting arm was developed by using FLUENT software compiling the UDF (User Defined Function) command. The simulation results show that the pressure distribution along the span of blade with the connecting arm model is significantly different from those without the connecting arm. To facilitate the validation of numerical model, the laboratory experiment has been carried out by using three different types of NACA aerofoil connecting arm and circle section connecting arm. And results show that the turbine with NACA0012 connecting arm has the best start-up performance which is 0.346 m/s and the peak point of power conversion coefficient is around 0.33. A further study has been performed and a conclusion is drawn that the aerofoil and thickness of connecting arm are the most important factors on the power conversion coefficient of the vertical axis tidal current turbine.

  16. Interpretation Of Assembly Task Constraints From Position And Force Sensory Data

    Science.gov (United States)

    Hou, E. S. H.; Lee, C. S. G.

    1990-03-01

    One of the major deficiencies in current robot control schemes is the lack of high-level knowledge in the feedback loop. Typically, the sensory data acquired are fed back to the robot controller with minimal amount of processing. However, by accumulating useful sensory data and processing them intelligently, one can obtain invaluable information about the state of the task being performed by the robot. This paper presents a method based on the screw theory for interpreting the position and force sensory data into high-level assembly task constraints. The position data are obtained from the joint angle encoders of the manipulator and the force data are obtained from a wrist force sensor attached to the mounting plate of the manipulator end-effector. The interpretation of the sensory data is divided into two subproblems: representation problem and interpretation problem. Spatial and physical constraints based on the screw axis and force axis of the manipulator are used to represent the high-level task constraints. Algorithms which yield least-squared error results are developed to obtain the spatial and physical constraints from the position and force data. The spatial and physical constraints obtained from the sensory data are then compared with the desired spatial and physical constraints to interpret the state of the assembly task. Computer simulation and experimental results for verifying the validity of the algorithms are also presented and discussed.

  17. Theory of Constraints (TOC)

    DEFF Research Database (Denmark)

    Michelsen, Aage U.

    2004-01-01

    Tankegangen bag Theory of Constraints samt planlægningsprincippet Drum-Buffer-Rope. Endvidere skitse af The Thinking Process.......Tankegangen bag Theory of Constraints samt planlægningsprincippet Drum-Buffer-Rope. Endvidere skitse af The Thinking Process....

  18. Credit Constraints in Education

    Science.gov (United States)

    Lochner, Lance; Monge-Naranjo, Alexander

    2012-01-01

    We review studies of the impact of credit constraints on the accumulation of human capital. Evidence suggests that credit constraints have recently become important for schooling and other aspects of households' behavior. We highlight the importance of early childhood investments, as their response largely determines the impact of credit…

  19. Theory of Constraints (TOC)

    DEFF Research Database (Denmark)

    Michelsen, Aage U.

    2004-01-01

    Tankegangen bag Theory of Constraints samt planlægningsprincippet Drum-Buffer-Rope. Endvidere skitse af The Thinking Process.......Tankegangen bag Theory of Constraints samt planlægningsprincippet Drum-Buffer-Rope. Endvidere skitse af The Thinking Process....

  20. Temporal Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Palamidessi, Catuscia; Valencia, Frank Dan

    2002-01-01

    The ntcc calculus is a model of non-deterministic temporal concurrent constraint programming. In this paper we study behavioral notions for this calculus. In the underlying computational model, concurrent constraint processes are executed in discrete time intervals. The behavioral notions studied...

  1. Evaluating Distributed Timing Constraints

    DEFF Research Database (Denmark)

    Kristensen, C.H.; Drejer, N.

    1994-01-01

    In this paper we describe a solution to the problem of implementing time-optimal evaluation of timing constraints in distributed real-time systems.......In this paper we describe a solution to the problem of implementing time-optimal evaluation of timing constraints in distributed real-time systems....

  2. Numerical and experimental investigation on the performance of three newly designed 100 kW-class tidal current turbines

    Directory of Open Access Journals (Sweden)

    Museok Song

    2012-09-01

    Full Text Available Three types of 100 kW-class tidal stream turbines are proposed and their performance is studied both numerically and experimentally. Following a wind turbine design procedure, a base blade is derived and two additional blades are newly designed focusing more on efficiency and cavitation. For the three designed turbines, a CFD is performed by using FLUENT. The calculations predict that the newly designed turbines perform better than the base turbine and the tip vortex can be reduced with additional efficiency increase by adopting a tip rake. The performance of the turbines is tested in a towing tank with 700 mm models. The scale problem is carefully investigated and the measurements are compared with the CFD results. All the prediction from the CFD is supported by the model experiment with some quantitative discrepancy. The maximum efficiencies are 0.49 (CFD and 0.45 (experiment at TSR 5.17 for the turbine with a tip rake.

  3. Infrared Constraint on Ultraviolet Theories

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Yuhsin [Cornell Univ., Ithaca, NY (United States)

    2012-08-01

    While our current paradigm of particle physics, the Standard Model (SM), has been extremely successful at explaining experiments, it is theoretically incomplete and must be embedded into a larger framework. In this thesis, we review the main motivations for theories beyond the SM (BSM) and the ways such theories can be constrained using low energy physics. The hierarchy problem, neutrino mass and the existence of dark matter (DM) are the main reasons why the SM is incomplete . Two of the most plausible theories that may solve the hierarchy problem are the Randall-Sundrum (RS) models and supersymmetry (SUSY). RS models usually suffer from strong flavor constraints, while SUSY models produce extra degrees of freedom that need to be hidden from current experiments. To show the importance of infrared (IR) physics constraints, we discuss the flavor bounds on the anarchic RS model in both the lepton and quark sectors. For SUSY models, we discuss the difficulties in obtaining a phenomenologically allowed gaugino mass, its relation to R-symmetry breaking, and how to build a model that avoids this problem. For the neutrino mass problem, we discuss the idea of generating small neutrino masses using compositeness. By requiring successful leptogenesis and the existence of warm dark matter (WDM), we can set various constraints on the hidden composite sector. Finally, to give an example of model independent bounds from collider experiments, we show how to constrain the DM–SM particle interactions using collider results with an effective coupling description.

  4. Decentralized Constraint Satisfaction

    CERN Document Server

    Duffy, K R; Leith, D J

    2011-01-01

    Constraint satisfaction problems (CSPs) lie at the heart of many modern industrial and commercial tasks. An important new collection of CSPs has recently been emerging that differ from classical problems in that they impose constraints on the class of algorithms that can be used to solve them. In computer network applications, these constraints arise as the variables within the CSP are located at physically distinct devices that cannot communicate. At each instant, every variable only knows if all its constraints are met or at least one is not. Consequently, the CSP's solution must be found using a decentralized approach. Existing algorithms for solving CSPs are either centralized or distributed, both of which violate these algorithmic constraints. In this article we present the first algorithm for solving CSPs that fulfills these new requirements. It is fully decentralized, making no use of a centralized controller or message-passing between variables. We prove that this algorithm converges with probability ...

  5. Constraints in Quantum Geometrodynamics

    CERN Document Server

    Gentle, A P; Kheyfets, A I; Miller, W A; Gentle, Adrian P.; George, Nathan D.; Kheyfets, Arkady; Miller, Warner A.

    2003-01-01

    We compare different treatments of the constraints in canonical quantum gravity. The standard approach on the superspace of 3-geometries treats the constraints as the sole carriers of the dynamic content of the theory, thus rendering the traditional dynamic equations obsolete. Quantization of the constraints in both the Dirac and ADM square root Hamiltonian approach lead to the well known problems of the description of time evolution. These problems of time are both of interpretational and technical nature. In contrast, the so-called geometrodynamic quantization procedure on the superspace of the true dynamic variables separates the issue of quantization from enforcing the constraints. The resulting theory takes into account the states that are off shell with respect to the constraints, and thus avoids the problems of time. Here, we develop, for the first time, the geometrodynamic quantization formalism in a general setting and show that it retains all essential features previously illustrated in the context ...

  6. Implementation of Excitation Inrush Current Analysis and Experimental Facility%励磁涌流分析及其实验装置的实现

    Institute of Scientific and Technical Information of China (English)

    刘兰荣; 赵志强; 王伟; 张晓光

    2014-01-01

    励磁涌流是变压器空载合闸时不可避免的现象。从实验角度对励磁涌流的表现加以分析,并以晶闸管配合交流接触器作为核心器件,制造了合闸相位角可控的励磁涌流发生控制装置,模拟实际中可能出现的各种励磁涌流现象,进行相关励磁涌流峰值、衰减特性等的分析。试验结果表明该装置可作为励磁涌流计算的有效验证手段。%The excitation inrush current is the inevitable phenomenon in transformer no-load closing. This paper analyzed the phenomenon of excitation inrush current from the corner of experiments. An excitation inrush current generation control device, controlled by the closing phase angle, with thyristors and AC contactor as the core components, was manufactured. This paper simulated various possible arisen phenomena of excitation inrush current in practice and analyzed the related peak value of excitation inrush current, the attenuation characteristics and so on. Experimental results show that the device could be the effective verification way to calculate excitation inrush current.

  7. Experimentally-Based Computational Investigation into Beat-To-Beat Variability in Ventricular Repolarization and Its Response to Ionic Current Inhibition.

    Directory of Open Access Journals (Sweden)

    E Pueyo

    Full Text Available Beat-to-beat variability in repolarization (BVR has been proposed as an arrhythmic risk marker for disease and pharmacological action. The mechanisms are unclear but BVR is thought to be a cell level manifestation of ion channel stochasticity, modulated by cell-to-cell differences in ionic conductances. In this study, we describe the construction of an experimentally-calibrated set of stochastic cardiac cell models that captures both BVR and cell-to-cell differences in BVR displayed in isolated canine action potential measurements using pharmacological agents. Simulated and experimental ranges of BVR are compared in control and under pharmacological inhibition, and the key ionic currents determining BVR under physiological and pharmacological conditions are identified. Results show that the 4-aminopyridine-sensitive transient outward potassium current, Ito1, is a fundamental driver of BVR in control and upon complete inhibition of the slow delayed rectifier potassium current, IKs. In contrast, IKs and the L-type calcium current, ICaL, become the major contributors to BVR upon inhibition of the fast delayed rectifier potassium current, IKr. This highlights both IKs and Ito1 as key contributors to repolarization reserve. Partial correlation analysis identifies the distribution of Ito1 channel numbers as an important independent determinant of the magnitude of BVR and drug-induced change in BVR in control and under pharmacological inhibition of ionic currents. Distributions in the number of IKs and ICaL channels only become independent determinants of the magnitude of BVR upon complete inhibition of IKr. These findings provide quantitative insights into the ionic causes of BVR as a marker for repolarization reserve, both under control condition and pharmacological inhibition.

  8. Self-Imposed Creativity Constraints

    DEFF Research Database (Denmark)

    Biskjaer, Michael Mose

    2013-01-01

    . As the majority of work in creativity research originates from psychology, the dissertation shows how the humanities – given their salient critical-analytical reflection and high concept awareness – can contribute new types of studies to creativity research, which, despite its blossoming as a field, is becoming...... increasingly fragmented and in need of new ‘big’ unifying questions. Hence the designation of the dissertation’s research approach. The four papers serve a dual purpose. They are contributions in their own right, and they provide partial answers to the overall research question. In this respect, the concept...... of the current dispersed studies on constraints in creativity, spanning psychology, engineering, philosophy, design, and aesthetics. (2) Definitions, concepts, and models of self-imposed creativity constraints for analytical application within and across creative domains, including the 6i model for demonstrating...

  9. Spurious claims for health-care products: an experimental approach to evaluating current UK legislation and its implementation.

    Science.gov (United States)

    Rose, Leslie B; Posadzki, Paul; Ernst, Edzard

    2012-01-01

    The lay media, and especially the Internet, contain many misleading claims for health products which have previously been inadequately regulated by consumer law. This was an experimental interventional survey within a consumer health-care setting. Three health products were chosen on the basis of being widely available on the UK market and having no available evidence of effectiveness. Twelve volunteers submitted 39 complaints to Consumer Direct (UK portal for the regulator Trading Standards) regarding false health claims, and 36 complaints were followed up for a maximum of 4.8 months. The mean time from submission of complaints to Consumer Direct to acknowledgement by the relevant Trading Standards office was 13 days. There were no responses from Trading Standards for 22% of complaints. At the end of the study one supplier had amended their website following Trading Standards advice, but did not stop all health claims. Another stopped advertising their product on the Internet and the third continued the health claims unchanged. EU directive 2005/29/EC is largely ineffective in preventing misleading health claims for consumer products in the UK.

  10. Development and evaluation of a high-resolution reanalysis of the East Australian Current region using the Regional Ocean Modelling System (ROMS 3.4) and Incremental Strong-Constraint 4-Dimensional Variational (IS4D-Var) data assimilation

    Science.gov (United States)

    Kerry, Colette; Powell, Brian; Roughan, Moninya; Oke, Peter

    2016-10-01

    As with other Western Boundary Currents globally, the East Australian Current (EAC) is highly variable making it a challenge to model and predict. For the EAC region, we combine a high-resolution state-of-the-art numerical ocean model with a variety of traditional and newly available observations using an advanced variational data assimilation scheme. The numerical model is configured using the Regional Ocean Modelling System (ROMS 3.4) and takes boundary forcing from the BlueLink ReANalysis (BRAN3). For the data assimilation, we use an Incremental Strong-Constraint 4-Dimensional Variational (IS4D-Var) scheme, which uses the model dynamics to perturb the initial conditions, atmospheric forcing, and boundary conditions, such that the modelled ocean state better fits and is in balance with the observations. This paper describes the data assimilative model configuration that achieves a significant reduction of the difference between the modelled solution and the observations to give a dynamically consistent "best estimate" of the ocean state over a 2-year period. The reanalysis is shown to represent both assimilated and non-assimilated observations well. It achieves mean spatially averaged root mean squared (rms) residuals with the observations of 7.6 cm for sea surface height (SSH) and 0.4 °C for sea surface temperature (SST) over the assimilation period. The time-mean rms residual for subsurface temperature measured by Argo floats is a maximum of 0.9 °C between water depths of 100 and 300 m and smaller throughout the rest of the water column. Velocities at several offshore and continental shelf moorings are well represented in the reanalysis with complex correlations between 0.8 and 1 for all observations in the upper 500 m. Surface radial velocities from a high-frequency radar array are assimilated and the reanalysis provides surface velocity estimates with complex correlations with observed velocities of 0.8-1 across the radar footprint. A comparison with

  11. Interaction between intention and environmental constraints on the fractal dynamics of human performance.

    Science.gov (United States)

    Washburn, Auriel; Coey, Charles A; Romero, Veronica; Malone, MaryLauren; Richardson, Michael J

    2015-11-01

    The current study investigated whether the influence of available task constraints on power-law scaling might be moderated by a participant's task intention. Participants performed a simple rhythmic movement task with the intention of controlling either movement period or amplitude, either with or without an experimental stimulus designed to constrain period. In the absence of the stimulus, differences in intention did not produce any changes in power-law scaling. When the stimulus was present, however, a shift toward more random fluctuations occurred in the corresponding task dimension, regardless of participants' intentions. More importantly, participants' intentions interacted with available task constraints to produce an even greater shift toward random variation when the task dimension constrained by the stimulus was also the dimension the participant intended to control. Together, the results suggest that intentions serve to more tightly constrain behavior to existing environmental constraints, evidenced by changes in the fractal scaling of task performance.

  12. Constraint-based reachability

    Directory of Open Access Journals (Sweden)

    Arnaud Gotlieb

    2013-02-01

    Full Text Available Iterative imperative programs can be considered as infinite-state systems computing over possibly unbounded domains. Studying reachability in these systems is challenging as it requires to deal with an infinite number of states with standard backward or forward exploration strategies. An approach that we call Constraint-based reachability, is proposed to address reachability problems by exploring program states using a constraint model of the whole program. The keypoint of the approach is to interpret imperative constructions such as conditionals, loops, array and memory manipulations with the fundamental notion of constraint over a computational domain. By combining constraint filtering and abstraction techniques, Constraint-based reachability is able to solve reachability problems which are usually outside the scope of backward or forward exploration strategies. This paper proposes an interpretation of classical filtering consistencies used in Constraint Programming as abstract domain computations, and shows how this approach can be used to produce a constraint solver that efficiently generates solutions for reachability problems that are unsolvable by other approaches.

  13. Relationship between protein structure and geometrical constraints

    DEFF Research Database (Denmark)

    Lund, Ole; Hansen, Jan; Brunak, Søren;

    1996-01-01

    We evaluate to what extent the structure of proteins can be deduced from incomplete knowledge of disulfide bridges, surface assignments, secondary structure assignments, and additional distance constraints. A cost function taking such constraints into account was used to obtain protein structures...... using a simple minimization algorithm. For small proteins, the approximate structure could be obtained using one additional distance constraint for each amino acid in the protein. We also studied the effect of using predicted secondary structure and surface assignments. The constraints used...... in this approach typically may be obtained from low-resolution experimental data. When using a cost function based on distances, half of the resulting structures will be mirrored, because the resulting structure and its mirror image will have the same cost. The secondary structure assignments were therefore...

  14. Experimental study of nonlinear interaction of plasma flow with charged thin current sheets: 2. Hall dynamics, mass and momentum transfer

    Directory of Open Access Journals (Sweden)

    S. Savin

    2006-01-01

    Full Text Available Proceeding with the analysis of Amata et al. (2005, we suggest that the general feature for the local transport at a thin magnetopause (MP consists of the penetration of ions from the magnetosheath with gyroradius larger than the MP width, and that, in crossing it, the transverse potential difference at the thin current sheet (TCS is acquired by these ions, providing a field-particle energy exchange without parallel electric fields. It is suggested that a part of the surface charge is self-consistently produced by deflection of ions in the course of inertial drift in the non-uniform electric field at MP. Consideration of the partial moments of ions with different energies demonstrates that the protons having gyroradii of roughly the same size or larger than the MP width carry fluxes normal to MP that are about 20% of the total flow in the plasma jet under MP. This is close to the excess of the ion transverse velocity over the cross-field drift speed in the plasma flow just inside MP (Amata et al., 2005, which conforms to the contribution of the finite-gyroradius inflow across MP. A linkage through the TCS between different plasmas results from the momentum conservation of the higher-energy ions. If the finite-gyroradius penetration occurs along the MP over ~1.5 RE from the observation site, then it can completely account for the formation of the jet under the MP. To provide the downstream acceleration of the flow near the MP via the cross-field drift, the weak magnetic field is suggested to rotate from its nearly parallel direction to the unperturbed flow toward being almost perpendicular to the accelerated flow near the MP. We discuss a deceleration of the higher-energy ions in the MP normal direction due to the interaction with finite-scale electric field bursts in the magnetosheath flow frame, equivalent to collisions, providing a charge separation. These effective collisions, with a nonlinear frequency proxy of the order of the proton

  15. Experimental study of the surface thermal signature of gravity currents: application to the assessment of lava flow effusion rate

    Science.gov (United States)

    Garel, F.; Kaminski, E.; Tait, S.; Limare, A.

    2011-12-01

    During an effusive volcanic eruption, the crisis management is mainly based on the prediction of lava flows advance and its velocity. As the spreading of lava flows is mainly controlled by its rheology and the eruptive mass flux, the key question is how to evaluate them during the eruption (rather than afterwards.) A relationship between the heat flux lost by the lava at its surface and the eruption rate is likely to exist, based on the first-order argument that higher eruption rates should correspond to larger power radiated by a lava flow. The semi-empirical formula developed by Harris and co-workers (e.g. Harris et al., Bull. Volc. 2007) is currently used to estimate lava flow rate from satellite surveys yielding the surface temperatures and area of the lava flow field. However, this approach is derived from a static thermal budget of the lava flow and does not explicitly model the time-evolution of the surface thermal signal. Here we propose laboratory experiments and theoretical studies of the cooling of a viscous axisymmetric gravity current fed at constant flux rate. We first consider the isoviscous case, for which the spreading is well-know. The experiments using silicon oil and the theoretical model both reveal the establishment of a steady surface thermal structure after a transient time. The steady state is a balance between surface cooling and heat advection in the flow. The radiated heat flux in the steady regime, a few days for a basaltic lava flow, depends mainly on the effusion rate rather than on the viscosity. In this regime, one thermal survey of the radiated power could provide a consistent estimate of the flow rate if the external cooling conditions (wind) are reasonably well constrained. We continue to investigate the relationship between the thermal radiated heat flux and the effusion rate by using in the experiments fluids with temperature-dependent viscosity (glucose syrup) or undergoing solidification while cooling (PEG wax). We observe a

  16. Imposing Constraints from the Source Tree on ITG Constraints for SMT

    Science.gov (United States)

    Yamamoto, Hirofumi; Okuma, Hideo; Sumita, Eiichiro

    In the current statistical machine translation (SMT), erroneous word reordering is one of the most serious problems. To resolve this problem, many word-reordering constraint techniques have been proposed. Inversion transduction grammar (ITG) is one of these constraints. In ITG constraints, target-side word order is obtained by rotating nodes of the source-side binary tree. In these node rotations, the source binary tree instance is not considered. Therefore, stronger constraints for word reordering can be obtained by imposing further constraints derived from the source tree on the ITG constraints. For example, for the source word sequence { a b c d }, ITG constraints allow a total of twenty-two target word orderings. However, when the source binary tree instance ((a b) (c d)) is given, our proposed “imposing source tree on ITG” (IST-ITG) constraints allow only eight word orderings. The reduction in the number of word-order permutations by our proposed stronger constraints efficiently suppresses erroneous word orderings. In our experiments with IST-ITG using the NIST MT08 English-to-Chinese translation track's data, the proposed method resulted in a 1.8-points improvement in character BLEU-4 (35.2 to 37.0) and a 6.2% lower CER (74.1 to 67.9%) compared with our baseline condition.

  17. Communication with Disturbance Constraints

    CERN Document Server

    Bandemer, Bernd

    2011-01-01

    The problem of communication with disturbance constraints is introduced. The rate-disturbance region is established for the single constraint case. The optimal encoding scheme turns out to be the same as the Han-Kobayashi scheme for the two user-pair interference channel. For communication with two disturbance constraints, a coding scheme and a corresponding inner bound for the deterministic case are presented. The results suggest a natural way to obtain a new inner bound on the capacity region of the interference channel with more than two user pairs.

  18. Optimization under Nonlinear Constraints

    OpenAIRE

    1982-01-01

    In this paper a timesaving method is proposed for maximizing likelihood functions when the parameter space is subject to nonlinear constraints, expressible as second order polynomials. The suggested approach is especially attractive when dealing with systems with many parameters.

  19. Experimental study of nonlinear interaction of plasma flow with charged thin current sheets: 1. Boundary structure and motion

    Directory of Open Access Journals (Sweden)

    E. Amata

    2006-01-01

    Full Text Available We study plasma transport at a thin magnetopause (MP, described hereafter as a thin current sheet (TCS, observed by Cluster at the southern cusp on 13 February 2001 around 20:01 UT. The Cluster observations generally agree with the predictions of the Gas Dynamic Convection Field (GDCF model in the magnetosheath (MSH up to the MSH boundary layer, where significant differences are seen. We find for the MP a normal roughly along the GSE x-axis, which implies a clear departure from the local average MP normal, a ~90 km thickness and an outward speed of 35 km/s. Two populations are identified in the MSH boundary layer: the first one roughly perpendicular to the MSH magnetic field, which we interpret as the "incident" MSH plasma, the second one mostly parallel to B. Just after the MP crossing a velocity jet is observed with a peak speed of 240 km/s, perpendicular to B, with MA=3 and β>10 (peak value 23. The magnetic field clock angle rotates by 70° across the MP. Ex is the main electric field component on both sides of the MP, displaying a bipolar signature, positive on the MSH side and negative on the opposite side, corresponding to a ~300 V electric potential jump across the TCS. The E×B velocity generally coincides with the perpendicular velocity measured by CIS; however, in the speed jet a difference between the two is observed, which suggests the need for an extra flow source. We propose that the MP TCS can act locally as an obstacle for low-energy ions (<350 eV, being transparent for ions with larger gyroradius. As a result, the penetration of plasma by finite gyroradius is considered as a possible source for the jet. The role of reconnection is briefly discussed. The electrodynamics of the TCS along with mass and momentum transfer across it are further discussed in the companion paper by Savin et al. (2006.

  20. Constraints and spandrels of interareal connectomes

    Science.gov (United States)

    Rubinov, Mikail

    2016-12-01

    Interareal connectomes are whole-brain wiring diagrams of white-matter pathways. Recent studies have identified modules, hubs, module hierarchies and rich clubs as structural hallmarks of these wiring diagrams. An influential current theory postulates that connectome modules are adequately explained by evolutionary pressures for wiring economy, but that the other hallmarks are not explained by such pressures and are therefore less trivial. Here, we use constraint network models to test these postulates in current gold-standard vertebrate and invertebrate interareal-connectome reconstructions. We show that empirical wiring-cost constraints inadequately explain connectome module organization, and that simultaneous module and hub constraints induce the structural byproducts of hierarchies and rich clubs. These byproducts, known as spandrels in evolutionary biology, include the structural substrate of the default-mode network. Our results imply that currently standard connectome characterizations are based on circular analyses or double dipping, and we emphasize an integrative approach to future connectome analyses for avoiding such pitfalls.

  1. CALCULATION-EXPERIMENTAL METHOD OF RESEARCH IN A METALLIC CONDUCTOR WITH THE PULSE CURRENT OF ELECTRONIC WAVEPACKAGES AND DE BROGLIE ELECTRONIC HALF-WAVES

    Directory of Open Access Journals (Sweden)

    M. I. Baranov

    2016-12-01

    Full Text Available Purpose. Development of calculation-experimental method for a discovery and study of electronic wavepackages (EWP and of de Broglie electronic half-waves in a metallic conductor with the pulse axial-flow current of high density. Methodology. Theoretical bases of the electrical engineering, bases of quantum physics, electrophysics bases of technique of high voltage and large pulsecurrents, and also bases of technique of measuring of permanent and variable electric value. Results. On the basis of generalization of results of research of features of the longitudinal wave periodic distributing of negatively charged transmitters of electric current of conductivity in the thin round continuous zincked steel wire offered and approved in the conditions of high-voltage laboratory method for a discovery and direct determination in him of geometrical parameters of «hot» and «cold» longitudinal areas quantized periodic longitudinal EWP and accordingly the mediated determination of values of the quantized lengths formative their de Broglie electronic half-waves. It is shown that results of close quantum mechanical calculations of EWP and quantized lengths λenz/2 of longitudinal de Broglie half-waves for the probed wire long l0 well comport with the results of the executed high temperature experiments on the powerful high-voltage generator of homopolar large pulse current of millisecond duration. Originality. First calculation-experimental a way the important for the theory of electricity fact of existence is set in a round metallic explorer with the impulsive axial-flow current of the quantized coherent de Broglie electronic half-waves, amplitudes of which at the quantum number of n=1,3,9 correspond the middles of «hot» longitudinal areas of EWP. Calculation quantum mechanical correlation of type of λenz/2=l0/n got experimental confirmation, in obedience to which on length of l0 conductor the integer of quantized electronic half-waves is always laid

  2. Constraints on the timeon model

    Science.gov (United States)

    Araki, Takeshi; Geng, C. Q.

    2009-04-01

    The timeon model recently proposed by Friedberg and Lee has a potential problem of flavor changing neutral currents (FCNCs) if the mass of the timeon is small. In order to avoid, we introduce a small dimensionless parameter to suppress FCNCs. Even in this case, we find that the timeon mass must be larger than 151 GeV to satisfy all the constraints from processes involving FCNCs in the quark sectors. We also extend the timeon model to the lepton sector and examine the leptonic processes.

  3. Constraints on the CP-Violating MSSM

    CERN Document Server

    Arbey, A; Godbole, R M; Mahmoudi, F

    2016-01-01

    We discuss the prospects for observing CP violation in the MSSM with six CP-violating phases, using a geometric approach to maximise CP-violating observables subject to the experimental upper bounds on electric dipole moments. We consider constraints from Higgs physics, flavour physics, the dark matter relic density and spin-independent scattering cross section with matter.

  4. Relating Weight Constraint and Aggregate Programs: Semantics and Representation

    CERN Document Server

    Liu, Guohua

    2011-01-01

    Weight constraint and aggregate programs are among the most widely used logic programs with constraints. In this paper, we relate the semantics of these two classes of programs, namely the stable model semantics for weight constraint programs and the answer set semantics based on conditional satisfaction for aggregate programs. Both classes of programs are instances of logic programs with constraints, and in particular, the answer set semantics for aggregate programs can be applied to weight constraint programs. We show that the two semantics are closely related. First, we show that for a broad class of weight constraint programs, called strongly satisfiable programs, the two semantics coincide. When they disagree, a stable model admitted by the stable model semantics may be circularly justified. We show that the gap between the two semantics can be closed by transforming a weight constraint program to a strongly satisfiable one, so that no circular models may be generated under the current implementation of ...

  5. Constraints on the parameters of the CKM matrix by End 1998

    CERN Document Server

    Parodi, F; Stocchi, A

    1999-01-01

    A review of the current status of the Cabibbo-Kobayashi-Maskawa matrix (CKM) is presented. This paper is an update of the results published in [1]. The experimental constraints imposed by the measurements of \\epsilon_K, V_{ub}/V_{cb}, \\Delta m_d and from the limit on \\Delta m_d are used. Values of the constraints and of the parameters entering into the constraints, which restrict the range of the \\bar{\\rho} and \\bar{\\eta} parameters, include recent measurements presented at 1998 Summer Conferences and progress obtained by lattice QCD collaborations. The results are: \\bar{\\rho}=0.202 ^{+0.053}_{-0.059},\\bar{\\eta}=0.340 \\pm 0.035, from which the angles \\alpha, ^{+ 0.29}_{-0.28} ,\\sin 2 \\beta = 0.725 ^{+0.050}_{-0.060} ,\\gamma= (59.5^{+8.5}_{-7.5})^{\\circ}. Without using the constraint from \\epsilon_K, external measurements or theoretical inputs have been removed, in turn, from the constraints and their respective probability density functions have been obtained. Central values and uncertainties on these quantit...

  6. The photogrammetric inner constraints

    Science.gov (United States)

    Dermanis, Athanasios

    A derivation of the complete inner constraints, which are required for obtaining "free network" solutions in close-range photogrammetry, is presented. The inner constraints are derived analytically for the bundle method, by exploiting the fact that the rows of their coefficient matrix from a basis for the null subspace of the design matrix used in the linearized observation equations. The derivation is independent of any particular choice of rotational parameters and examples are given for three types of rotation angles used in photogrammetry, as well as for the Rodriguez elements. A convenient algorithm based on the use of the S-transformation is presented, for the computation of free solutions with either inner or partial inner constraints. This approach is finally compared with alternative approaches to free network solutions.

  7. Constraint algebra in bigravity

    Energy Technology Data Exchange (ETDEWEB)

    Soloviev, V. O., E-mail: Vladimir.Soloviev@ihep.ru [National Research Center Kurchatov Institute, Institute for High Energy Physics (Russian Federation)

    2015-07-15

    The number of degrees of freedom in bigravity theory is found for a potential of general form and also for the potential proposed by de Rham, Gabadadze, and Tolley (dRGT). This aim is pursued via constructing a Hamiltonian formalismand studying the Poisson algebra of constraints. A general potential leads to a theory featuring four first-class constraints generated by general covariance. The vanishing of the respective Hessian is a crucial property of the dRGT potential, and this leads to the appearance of two additional second-class constraints and, hence, to the exclusion of a superfluous degree of freedom—that is, the Boulware—Deser ghost. The use of a method that permits avoiding an explicit expression for the dRGT potential is a distinctive feature of the present study.

  8. Constraints as evolutionary systems

    CERN Document Server

    Rácz, István

    2016-01-01

    The constraint equations for smooth $[n+1]$-dimensional (with $n\\geq 3$) Riemannian or Lorentzian spaces satisfying the Einstein field equations are considered. It is shown, regardless of the signature of the primary space, that the constraints can be put into the form of an evolutionary system comprised either by a first order symmetric hyperbolic system and a parabolic equation or, alternatively, by a strongly hyperbolic system and a subsidiary algebraic relation. In both cases the (local) existence and uniqueness of solutions are also discussed.

  9. Constraint-based scheduling applying constraint programming to scheduling problems

    CERN Document Server

    Baptiste, Philippe; Nuijten, Wim

    2001-01-01

    Constraint Programming is a problem-solving paradigm that establishes a clear distinction between two pivotal aspects of a problem: (1) a precise definition of the constraints that define the problem to be solved and (2) the algorithms and heuristics enabling the selection of decisions to solve the problem. It is because of these capabilities that Constraint Programming is increasingly being employed as a problem-solving tool to solve scheduling problems. Hence the development of Constraint-Based Scheduling as a field of study. The aim of this book is to provide an overview of the most widely used Constraint-Based Scheduling techniques. Following the principles of Constraint Programming, the book consists of three distinct parts: The first chapter introduces the basic principles of Constraint Programming and provides a model of the constraints that are the most often encountered in scheduling problems. Chapters 2, 3, 4, and 5 are focused on the propagation of resource constraints, which usually are responsibl...

  10. Constraints on single-field inflation

    Energy Technology Data Exchange (ETDEWEB)

    Pirtskhalava, David [Institut de Théorie des Phénoménes Physiques,EPFL Lausanne (Switzerland); Santoni, Luca; Trincherini, Enrico [Scuola Normale Superiore,Piazza dei Cavalieri 7, 56126, Pisa (Italy); INFN - Sezione di Pisa,56200, Pisa (Italy)

    2016-06-28

    Many alternatives to canonical slow-roll inflation have been proposed over the years, one of the main motivations being to have a model, capable of generating observable values of non-Gaussianity. In this work, we (re-)explore the physical implications of a great majority of such models within a single, effective field theory framework (including novel models with large non-Gaussianity discussed for the first time below). The constraints we apply — both theoretical and experimental — are found to be rather robust, determined to a great extent by just three parameters: the coefficients of the quadratic EFT operators (δN){sup 2} and δNδE, and the slow-roll parameter ε. This allows to significantly limit the majority of single-field alternatives to canonical slow-roll inflation. While the existing data still leaves some room for most of the considered models, the situation would change dramatically if the current upper limit on the tensor-to-scalar ratio decreased down to r<10{sup −2}. Apart from inflationary models driven by plateau-like potentials, the single-field model that would have a chance of surviving this bound is the recently proposed slow-roll inflation with weakly-broken galileon symmetry. In contrast to canonical slow-roll inflation, the latter model can support r<10{sup −2} even if driven by a convex potential, as well as generate observable values for the amplitude of non-Gaussianity.

  11. Method and System for Air Traffic Rerouting for Airspace Constraint Resolution

    Science.gov (United States)

    Sheth, Kapil S. (Inventor); McNally, B. David (Inventor); Erzberger, Heinz (Inventor); Morando, Alexander R. (Inventor); Clymer, Alexis A. (Inventor); Shih, Fu-tai (Inventor)

    2017-01-01

    A dynamic constraint avoidance route system automatically analyzes routes of aircraft flying, or to be flown, in or near constraint regions and attempts to find more time and fuel efficient reroutes around current and predicted constraints. The dynamic constraint avoidance route system continuously analyzes all flight routes and provides reroute advisories that are dynamically updated in real time. The dynamic constraint avoidance route system includes a graphical user interface that allows users to visualize, evaluate, modify if necessary, and implement proposed reroutes.

  12. Uso da corrente catódica de alta voltagem sobre a dor em compressão nervosa experimental Use of high-voltage cathodic current for pain in experimental nerve compression

    Directory of Open Access Journals (Sweden)

    Gladson Ricardo Flor Bertolini

    2012-04-01

    Full Text Available OBJETIVO: Avaliar o efeito da corrente catódica de alta voltagem sobre a dor em um modelo experimental de ciatalgia. MÉTODOS: Foram utilizados 16 ratos Wistar, machos, submetidos a um modelo de ciatalgia experimental no membro pélvico direito. Os sujeitos foram divididos em grupo simulacro (GS e grupo tratado com corrente catódica (GP- por 20 min diários durante 10 dias. O modelo de compressão foi realizado com amarria por fio catgut 4.0 cromado, em quatro pontos ao longo do nervo isquiático. A avaliação da nocicepção foi realizada, de forma funcional, com o tempo de elevação da pata (TEP, e à pressão, pelo limiar de retirada, via analgesímetro eletrônico. Os dados foram coletados antes do modelo de ciatalgia (AV1, três dias depois da compressão (antes, AV2, e após o tratamento, AV3, após o quinto dia de tratamento (AV4 e em seguida ao décimo dia de tratamento (AV5. RESULTADOS: Pela avaliação funcional, em ambos os grupos houve aumento da nocicepção, sem redução da mesma em qualquer momento da avaliação. À pressão, no entanto, o GS mostrou redução do limiar de retirada em todos os momentos, enquanto o GP- apresentou redução do limiar apenas inicialmente - em AV5 o limiar foi restaurado. CONCLUSÃO: Não houve alteração na nocicepção pela avaliação funcional; porém, à pressão, o tratamento com corrente catódica mostrou efeito com a somatória de terapias.OBJECTIVE: To assess the effect of high-voltage cathodic current on pain from a sciatica experimental model. METHODS: A total of 16 male Wistar rats were submitted to the sciatica experimental model in the right hind paw. They were divided into sham group (GS and group treated with cathodic current (GP- for 20 min/daily, for 10 days. The model of sciatic compression was performed with a 4.0-chromic catgut thread tie in four points of the sciatic nerve. Assessment of nociception was performed by measuring the time during which the animal held its hind

  13. Identification of steel bars immersed in reinforced concrete based on experimental results of eddy current testing and artificial neural network analysis

    Science.gov (United States)

    de Alcantara, Naasson

    2013-03-01

    This paper presents an experimental research on the use of eddy current testing (ECT) and artificial neural networks (ANNs) in order to identify the gauge and position of steel bars immersed in concrete structures. The paper presents details of the ECT probe and concrete specimens constructed for the tests, and a study about the influence of the concrete on the values of measured voltages. After this, new measurements were done with a greater number of specimens, simulating a field condition and the results were used to generate training and validation vectors for multilayer perceptron ANNs. The results show a high percentage of correct identification with respect to both, the gauge of the bar and of the thickness of the concrete cover.

  14. Maturational Constraints and First Language Attrition

    Science.gov (United States)

    Bylund, Emanuel

    2009-01-01

    The aim of the article is to examine how first language attrition research on maturational constraints interprets and links its findings to current views on maturation in the field of second language acquisition. It is argued that attrition research exhibits certain inconsistencies in the interpretation of the structural characteristics of the…

  15. Comparative antioxidant status in freshwater fish Carassius auratus exposed to six current-use brominated flame retardants: A combined experimental and theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Mingbao; Qu, Ruijuan; Wang, Chao; Wang, Liansheng; Wang, Zunyao, E-mail: wangzun315cn@163.com

    2013-09-15

    Highlights: •A combined experimental and theoretical approach was used for risk assessments of six BFRs in fish. •Oxidative stress biomarkers were measured for toxicity identification. •Toxicity order was proposed via the integrated biomarker response. •Theoretical calculations were performed to analyze the BFRs toxicity. -- Abstract: Decabromodiphenyl ether (BDE-209) and several non-polybrominated diphenyl ether (PBDE) brominated flame retardants (BFRs), such as tetrabromobisphenol A (TBBPA), hexabromocyclododecane (HBCD), decabromodiphenyl ethane (DBDPE), hexabromobenzene (HBB) and pentabromotoluene (PBT), are persistent halogenated contaminants ubiquitously detected in aquatic systems. However, data on comparative toxicological effects of these BFRs are lacking for fish. In this study, a combined experimental and theoretical approach was used to compare and analyze the effects of these BFRs on biochemical biomarkers in liver of Carassius auratus injected intraperitoneally with different doses (10 and 100 mg/kg) for 7, 14 and 30 days. Oxidative stress was evoked evidently for the prolonged exposure, represented by the significantly altered indices (superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione, and malondialdehyde). The integrated biomarker response (IBR) index ranked biotoxicity as: PBT > HBB > HBCD > TBBPA > BDE-209 > DBDPE. Quantum chemical calculations (electronic parameters, frontier molecular orbitals, and Wiberg bond order) were performed for theoretical analysis. Notably, some descriptors were correlated with the toxicity order, probably implying the existence of a potential structure–activity relationship when more BFRs were included. Besides, theoretical calculations also provided some valuable information regarding the molecular characteristics and metabolic pathways of these current-use BFRs, which may facilitate the understanding on their environmental behavior and fate. Overall, this study adopted a combined

  16. Constraint Optimization Literature Review

    Science.gov (United States)

    2015-11-01

    COPs. 15. SUBJECT TERMS high-performance computing, mobile ad hoc network, optimization, constraint, satisfaction 16. SECURITY CLASSIFICATION OF: 17...France): INRA Editions; 1996. p. 111–150. Black PE. Branch-and-bound. US national institute of standards and technology dictionary of algorithms

  17. A Review of Constraint-Handling Techniques for Evolution Strategies

    Directory of Open Access Journals (Sweden)

    Oliver Kramer

    2010-01-01

    Full Text Available Evolution strategies are successful global optimization methods. In many practical numerical problems constraints are not explicitly given. Evolution strategies have to incorporate techniques to optimize in restricted solution spaces. Famous constraint-handling techniques are penalty and multiobjective approaches. Past work has shown that in particular an ill-conditioned alignment between the coordinate system of Gaussian mutation and the constraint boundaries leads to premature convergence. Covariance matrix adaptation evolution strategies offer a solution to this alignment problem. Last, metamodeling of the constraint boundary leads to significant savings of constraint function calls and to a speedup by repairing infeasible solutions. This work gives a brief overview over constraint-handling methods for evolution strategies by demonstrating the approaches experimentally on two exemplary constrained problems.

  18. Global Constraints on a Heavy Neutrino

    CERN Document Server

    de Gouvêa, André

    2015-01-01

    We estimate constraints on the existence of a heavy, mostly sterile neutrino with mass between 10 eV and 1 TeV. We improve upon previous analyses by performing a global combination and expanding the experimental inputs to simultaneously include tests for lepton universality, lepton flavor violating processes, electroweak precision data, dipole moments, and neutrinoless double beta decay. Assuming the heavy neutrino and its decay products are invisible to detection, we further include, in a self-consistent manner, constraints from direct kinematic searches, the kinematics of muon decay, cosmology, and neutrino oscillations, in order to estimate constraints on the values of $|U_{e4}|^2$, $|U_{\\mu4}|^2$, and $|U_{\\tau4}|^2$.

  19. Expressing Model Constraints Visually with VMQL

    DEFF Research Database (Denmark)

    Störrle, Harald

    2011-01-01

    OCL is the de facto standard language for expressing constraints and queries on UML models. However, OCL expressions are very difficult to create, understand, and maintain, even with the sophisticated tool support now available. In this paper, we propose to use the Visual Model Query Language (VMQL......) for specifying constraints on UML models. We examine VMQL's usability by controlled experiments and its expressiveness by a representative sample. We conclude that VMQL is less expressive than OCL, although expressive enough for most of the constraints in the sample. In terms of usability, however, VMQL...... is superior to OCL, although the experimental evidence we present here is not as compelling as the one we presented when comparing VMQL and OCL on model querying....

  20. Analytical modelling and experimental verification of the three-dimensional current distribution on the top surface of silicon solar cells operating under concentrated sunlight

    Energy Technology Data Exchange (ETDEWEB)

    Costagliola, Maurizio; Riccio, Michele; Irace, Andrea; Breglio, Gianluca; Daliento, Santolo [Department of Biomedical, Electronics and Telecommunications Engineering, University of Naples ' ' Federico II' ' , via Claudio 21, 80125 Naples (Italy)

    2011-03-15

    The approximation that the current is constant in any point of the emitter is not true for solar cells operating under concentrated sunlight. The transverse paths followed by photogenerated carriers to reach metal grid electrodes causes voltage drops leading to non-uniform distributed surface potential and a consequent reduction of the conversion efficiency. Moreover, concentrating lens often provide non-uniform light intensity thus worsening non-uniform current distribution. The correct design of surface geometry of the cell (metal grid, emitter depth, sheet resistance) should always take into account the above effects. Unfortunately a lack of reliable models still exists. In this paper we analytically solve the three-dimensional semiconductor equations with proper boundary conditions and taking into account, as source term, a distributed generation contribute. The reliability of the model has been tested by numerical simulations and experimentally verified with a lock-in thermography technique (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. REDUCTION OF CONSTRAINTS FOR COUPLED OPERATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Raszewski, F.; Edwards, T.

    2009-12-15

    The homogeneity constraint was implemented in the Defense Waste Processing Facility (DWPF) Product Composition Control System (PCCS) to help ensure that the current durability models would be applicable to the glass compositions being processed during DWPF operations. While the homogeneity constraint is typically an issue at lower waste loadings (WLs), it may impact the operating windows for DWPF operations, where the glass forming systems may be limited to lower waste loadings based on fissile or heat load limits. In the sludge batch 1b (SB1b) variability study, application of the homogeneity constraint at the measurement acceptability region (MAR) limit eliminated much of the potential operating window for DWPF. As a result, Edwards and Brown developed criteria that allowed DWPF to relax the homogeneity constraint from the MAR to the property acceptance region (PAR) criterion, which opened up the operating window for DWPF operations. These criteria are defined as: (1) use the alumina constraint as currently implemented in PCCS (Al{sub 2}O{sub 3} {ge} 3 wt%) and add a sum of alkali constraint with an upper limit of 19.3 wt% ({Sigma}M{sub 2}O < 19.3 wt%), or (2) adjust the lower limit on the Al{sub 2}O{sub 3} constraint to 4 wt% (Al{sub 2}O{sub 3} {ge} 4 wt%). Herman et al. previously demonstrated that these criteria could be used to replace the homogeneity constraint for future sludge-only batches. The compositional region encompassing coupled operations flowsheets could not be bounded as these flowsheets were unknown at the time. With the initiation of coupled operations at DWPF in 2008, the need to revisit the homogeneity constraint was realized. This constraint was specifically addressed through the variability study for SB5 where it was shown that the homogeneity constraint could be ignored if the alumina and alkali constraints were imposed. Additional benefit could be gained if the homogeneity constraint could be replaced by the Al{sub 2}O{sub 3} and sum of

  2. REDUCTION OF CONSTRAINTS FOR COUPLED OPERATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Raszewski, F.; Edwards, T.

    2009-12-15

    The homogeneity constraint was implemented in the Defense Waste Processing Facility (DWPF) Product Composition Control System (PCCS) to help ensure that the current durability models would be applicable to the glass compositions being processed during DWPF operations. While the homogeneity constraint is typically an issue at lower waste loadings (WLs), it may impact the operating windows for DWPF operations, where the glass forming systems may be limited to lower waste loadings based on fissile or heat load limits. In the sludge batch 1b (SB1b) variability study, application of the homogeneity constraint at the measurement acceptability region (MAR) limit eliminated much of the potential operating window for DWPF. As a result, Edwards and Brown developed criteria that allowed DWPF to relax the homogeneity constraint from the MAR to the property acceptance region (PAR) criterion, which opened up the operating window for DWPF operations. These criteria are defined as: (1) use the alumina constraint as currently implemented in PCCS (Al{sub 2}O{sub 3} {ge} 3 wt%) and add a sum of alkali constraint with an upper limit of 19.3 wt% ({Sigma}M{sub 2}O < 19.3 wt%), or (2) adjust the lower limit on the Al{sub 2}O{sub 3} constraint to 4 wt% (Al{sub 2}O{sub 3} {ge} 4 wt%). Herman et al. previously demonstrated that these criteria could be used to replace the homogeneity constraint for future sludge-only batches. The compositional region encompassing coupled operations flowsheets could not be bounded as these flowsheets were unknown at the time. With the initiation of coupled operations at DWPF in 2008, the need to revisit the homogeneity constraint was realized. This constraint was specifically addressed through the variability study for SB5 where it was shown that the homogeneity constraint could be ignored if the alumina and alkali constraints were imposed. Additional benefit could be gained if the homogeneity constraint could be replaced by the Al{sub 2}O{sub 3} and sum of

  3. Experimental study on rectangular tidal current turbines%矩形潮流能水轮机性能的实验研究

    Institute of Scientific and Technical Information of China (English)

    陈展; 马勇; 张亮; 苏国卿

    2013-01-01

    To study the performance of rectangular tidal current turbines,a rectangular tidal current turbine and its experimental model were designed.An experiment platform was established and the experiment instrument and devices were selected.Then,some experiments were conducted,including the model of reciprocating flow experiment,the changing installation angle experiments,the impact of compactness experiment and the output power in different flow velocity experiment.The experimental results show that the rectangular tidal current turbine has good two-way flow of unidirectional rotation characteristic and the forward and reverse flows with the same energy capture capacity in the case of a constant flow velocity; when installation angle Ψ=±15°,the tidal turbine's ability of energy-capture is superior to the one when the installation angle Ψ=± 5°; the tidal turbine's ability of energycapture increases as the compactness increases within different speed ratio intervals; the peak value of output power increases with the increase of the flow velocity and the peak point moves right.%为了研究矩形潮流能水轮机的性能,设计了矩形潮流能水轮机及其实验模型装置,构建了实验平台,选配了实验仪器和设备,进行矩形潮流能水轮机模型的往复流及变安装摆角实验、密实度影响实验和不同流速下的功率输出实验.实验结果表明:矩形水轮机具有良好的双向来流单向旋转特性,在来流速度大小恒定的情况下,正向来流和反向来流具有相同的能量捕获能力;当安装摆角Ψ=±15°时,水轮机的能量捕获能力优于Ψ=±5°时的;不同速比区间内,随密实度增加,水轮机的获能能力也相应增加;流速增加,输出功率峰值增大,峰值点右移.

  4. Time constraints in the alcohol purchase task.

    Science.gov (United States)

    Kaplan, Brent A; Reed, Derek D; Murphy, James G; Henley, Amy J; Reed, Florence D DiGennaro; Roma, Peter G; Hursh, Steven R

    2017-06-01

    Hypothetical purchase tasks have advanced behavioral economic evaluations of demand by circumventing practical and ethical restrictions associated with delivering drug reinforcers to participants. Numerous studies examining the reliability and validity of purchase task methodology suggest that it is a valuable method for assessing demand that warrants continued use and evaluation. Within the literature examining purchase tasks, the alcohol purchase task (APT) has received the most investigation, and currently represents the most experimentally validated variant. However, inconsistencies in purchase task methodology between studies exist, even within APT studies, and, to date, none have assessed the influence of experimental economic constraints on responding. This study examined changes in Q0 (reported consumption when drinks are free), breakpoint (price that suppresses consumption), and α (rate of change in demand elasticity) in the presence of different hypothetical durations of access to alcohol in an APT. One hundred seventy-nine participants (94 males, 85 females) from Amazon Mechanical Turk completed 3 APTs that varied in the duration of time at a party (i.e., access to alcoholic beverages) as described in the APT instructions (i.e., vignette). The 3 durations included 5-hr (used by Murphy et al., 2013), 1-hr, and 9-hr time frames. We found that hypothetical duration of access was significantly related to Q0 and breakpoint at the individual level. Additionally, group-level mean α decreased significantly with increases in duration of access, thus indicating relatively higher demand for alcohol with longer durations of access. We discuss implications for conducting hypothetical purchase task research and alcohol misuse prevention efforts. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  5. A constraint algorithm for singular Lagrangians subjected to nonholonomic constraints

    Energy Technology Data Exchange (ETDEWEB)

    de Leon, M. [Instituto de Matematicas y Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 123, 28006 Madrid (Spain); de Diego, D.M. [Departamento de Economia Aplicada Cuantitativa, Facultad de Ciencias Economicas y Empresariales, UNED, 28040 Madrid (Spain)

    1997-06-01

    We construct a constraint algorithm for singular Lagrangian systems subjected to nonholonomic constraints which generalizes that of Dirac for constrained Hamiltonian systems. {copyright} {ital 1997 American Institute of Physics.}

  6. Pair Production Constraints on Superluminal Neutrinos Revisited

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, Stanley J.; /SLAC; Gardner, Susan; /Kentucky U.

    2012-02-16

    We revisit the pair creation constraint on superluminal neutrinos considered by Cohen and Glashow in order to clarify which types of superluminal models are constrained. We show that a model in which the superluminal neutrino is effectively light-like can evade the Cohen-Glashow constraint. In summary, any model for which the CG pair production process operates is excluded because such timelike neutrinos would not be detected by OPERA or other experiments. However, a superluminal neutrino which is effectively lightlike with fixed p{sup 2} can evade the Cohen-Glashow constraint because of energy-momentum conservation. The coincidence involved in explaining the SN1987A constraint certainly makes such a picture improbable - but it is still intrinsically possible. The lightlike model is appealing in that it does not violate Lorentz symmetry in particle interactions, although one would expect Hughes-Drever tests to turn up a violation eventually. Other evasions of the CG constraints are also possible; perhaps, e.g., the neutrino takes a 'short cut' through extra dimensions or suffers anomalous acceleration in matter. Irrespective of the OPERA result, Lorentz-violating interactions remain possible, and ongoing experimental investigation of such possibilities should continue.

  7. Linear programming analysis of the R-parity violation within EDM-constraints

    Science.gov (United States)

    Yamanaka, Nodoka; Sato, Toru; Kubota, Takahiro

    2014-12-01

    The constraint on the R-parity violating supersymmetric interactions is discussed in the light of current experimental data of the electric dipole moment of neutron, 129Xe , 205Tl, and 199Hg atoms, and YbF and ThO molecules. To investigate the constraints without relying upon the assumption of the dominance of a particular combination of couplings over all the rest, an extensive use is made of the linear programming method in the scan of the parameter space. We give maximally possible values for the EDMs of the proton, deuteron, 3He nucleus, 211Rn, 225Ra, 210Fr, and the R-correlation of the neutron beta decay within the constraints from the current experimental data of the EDMs of neutron, 129Xe, 205Tl, and 199Hg atoms, and YbF and ThO molecules using the linear programming method. It is found that the R-correlation of the neutron beta decay and hadronic EDMs are very useful observables to constrain definite regions of the parameter space of the R-parity violating supersymmetry.

  8. Dynamical Constraints on Exoplanets

    CERN Document Server

    Horner, Jonti; Tinney, Chris; Hinse, Tobias C; Marshall, Jonathan P

    2013-01-01

    Dynamical studies of new exoplanet systems are a critical component of the discovery and characterisation process. Such studies can provide firmer constraints on the parameters of the newly discovered planets, and may even reveal that the proposed planets do not stand up to dynamical scrutiny. Here, we demonstrate how dynamical studies can assist the characterisation of such systems through two examples: QS Virginis and HD 73526.

  9. (non) Emergent Constraints

    Science.gov (United States)

    Jackson, C. S.; Hattab, M. W.; Huerta, G.

    2014-12-01

    Emergent constraints are observable quantities that provide some physical basis for testing or predicting how a climate model will respond to greenhouse gas forcing. Very few such constraints have been identified for the multi-model CMIP archive. Here we explore the question of whether constraints that apply to a single model, a perturbed parameter ensemble (PPE) of the Community Atmosphere Model (CAM3.1), can be applied to predicting the climate sensitivities of models within the CMIP archive. In particular we construct our predictive patterns from multivariate EOFs of the CAM3.1 ensemble control climate. Multiple regressive statistical models were created that do an excellent job of predicting CAM3.1 sensitivity to greenhouse gas forcing. However, these same patterns fail spectacularly to predict sensitivities of models within the CMIP archive. We attribute this failure to several factors. First, and perhaps the most important, is that the structures affecting climate sensitivity in CAM3.1 have a unique signature in the space of our multivariate EOF patterns that are unlike any other climate model. That is to say, we should not expect CAM3.1 to represent the way another models within CMIP archive respond to greenhouse gas forcing. The second, perhaps related, reason is that the CAM3.1 PPE does a poor job of spanning the range of climates and responses found within the CMIP archive. We shall discuss the implications of these results for the prospect of finding emergent constraints within the CMIP archive. We will also discuss what this may mean for establishing uncertainties in climate projections.

  10. The NCL natural constraint language

    CERN Document Server

    Zhou, Jianyang

    2012-01-01

    This book presents the Natural Constraint Language (NCL) language, a description language in conventional mathematical logic for modeling and solving constraint satisfaction problems. It uses illustrations and tutorials to detail NCL and its applications.

  11. Lorentz violation. Motivation and new constraints

    Energy Technology Data Exchange (ETDEWEB)

    Liberati, S. [Scuola Internazionale Superiore di Studi Avanzati SISSA, Trieste (Italy); Istituto Nazionale di Fisica Nucleare INFN, Sezione di Trieste (Italy); Maccione, L. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2009-09-15

    We review the main theoretical motivations and observational constraints on Planck scale sup-pressed violations of Lorentz invariance. After introducing the problems related to the phenomenological study of quantum gravitational effects, we discuss the main theoretical frameworks within which possible departures from Lorentz invariance can be described. In particular, we focus on the framework of Effective Field Theory, describing several possible ways of including Lorentz violation therein and discussing their theoretical viability. We review the main low energy effects that are expected in this framework. We discuss the current observational constraints on such a framework, focusing on those achievable through high-energy astrophysics observations. In this context we present a summary of the most recent and strongest constraints on QED with Lorentz violating non-renormalizable operators. Finally, we discuss the present status of the field and its future perspectives. (orig.)

  12. The transmission interface constraint problem. Revision

    Energy Technology Data Exchange (ETDEWEB)

    Baldick, R.; Kahn, E.

    1994-10-01

    Electric power transmission systems exhibit a number of complex constraints on their operation and usage. When a network is subject to a constraint that limits the amount of power that can be moved from one region to another, there is said to be an interface limit. The power systems literature gives no general treatment of the engineering-economics of this ubiquitous phenomenon. Particular aspects of interface limits are typically discussed in sophisticated technical detail, but the general engineering-economic trade-offs involved in relieving interface constraints have not been systematically addressed. We approach this problem in the spirit of a heuristic model. Such models are quite valuable under current industry conditions because they delineate technical opportunities and choices in situations where there may be conflicting views among competing parties and regulatory authorities. We organize and enumerate the choices, clarify the practical conditions that dictate the optimum in particular cases, and help to motivate the final choices made by planners.

  13. Fluence map optimization (FMO) with dose-volume constraints in IMRT using the geometric distance sorting method

    Science.gov (United States)

    Lan, Yihua; Li, Cunhua; Ren, Haozheng; Zhang, Yong; Min, Zhifang

    2012-10-01

    A new heuristic algorithm based on the so-called geometric distance sorting technique is proposed for solving the fluence map optimization with dose-volume constraints which is one of the most essential tasks for inverse planning in IMRT. The framework of the proposed method is basically an iterative process which begins with a simple linear constrained quadratic optimization model without considering any dose-volume constraints, and then the dose constraints for the voxels violating the dose-volume constraints are gradually added into the quadratic optimization model step by step until all the dose-volume constraints are satisfied. In each iteration step, an interior point method is adopted to solve each new linear constrained quadratic programming. For choosing the proper candidate voxels for the current dose constraint adding, a so-called geometric distance defined in the transformed standard quadratic form of the fluence map optimization model was used to guide the selection of the voxels. The new geometric distance sorting technique can mostly reduce the unexpected increase of the objective function value caused inevitably by the constraint adding. It can be regarded as an upgrading to the traditional dose sorting technique. The geometry explanation for the proposed method is also given and a proposition is proved to support our heuristic idea. In addition, a smart constraint adding/deleting strategy is designed to ensure a stable iteration convergence. The new algorithm is tested on four cases including head-neck, a prostate, a lung and an oropharyngeal, and compared with the algorithm based on the traditional dose sorting technique. Experimental results showed that the proposed method is more suitable for guiding the selection of new constraints than the traditional dose sorting method, especially for the cases whose target regions are in non-convex shapes. It is a more efficient optimization technique to some extent for choosing constraints than the dose

  14. Constraints on Relaxion Windows

    CERN Document Server

    Choi, Kiwoon

    2016-01-01

    We examine low energy phenomenology of the relaxion solution to the weak scale hierarchy problem. Assuming that the Hubble friction is responsible for the dissipation of relaxion energy, we identify the cosmological relaxion window which corresponds to the parameter region compatible with a given value of the acceptable number of inflationary $e$-foldings. We then discuss a variety of observational constraints on the relaxion window, while focusing on the case that the barrier potential to stabilize the relaxion is induced by new physics, rather than by low energy QCD dynamics. We find that majority of the parameter space with a relaxion mass $m_\\phi\\gtrsim 100$ eV or a relaxion decay constant $f\\lesssim 10^7$ GeV is excluded by existing constraints. There is an interesting small parameter region with $m_\\phi\\sim \\,0.2-1$ GeV and $f\\sim\\, {\\rm few}-10$ TeV, which is allowed by existing constraints, but can be probed soon by future beam dump experiment such as the SHiP experiment, or by improved EDM experiment...

  15. Current Situation of Modified Constraint-induced Movement Therapy Used in Children with Hemiplegia (review)%改良强制性诱导运动疗法在偏瘫儿童康复中的应用现状

    Institute of Scientific and Technical Information of China (English)

    董婕; 吴卫红

    2014-01-01

    儿童偏瘫是儿童脑损伤后较常见的一种障碍类型。由于多种原因,偏瘫儿童患侧上肢功能改善比较困难,尤其是患手的功能。近年来提出用于儿童的改良强制性诱导运动疗法,本文就目前此方法在偏瘫儿童康复中的应用情况进行总结。%Hemiplegia is a common type of physical disability in children with brain damage. For many kinds of reasons, the outcome of rehabilitation of the affected upper limb is not good enough, especially in the affected hand. Recently, many studies engaged in the modi-fied Constraint-induced Movement Therapy (mCIMT) to explore the child-friendly way of restraint to improve hand function in hemiplegic children, and were summarized in this paper.

  16. What controls open-pore and residual currents in the first sensing zone of alpha-hemolysin nanopore? Combined experimental and theoretical study

    Science.gov (United States)

    de Biase, Pablo M.; Ervin, Eric N.; Pal, Prithwish; Samoylova, Olga; Markosyan, Suren; Keehan, Michael G.; Barrall, Geoffrey A.; Noskov, Sergei Yu.

    2016-06-01

    The electrophoretic transport of single-stranded DNA through biological nanopores such as alpha-hemolysin (αHL) is a promising and cost-effective technology with the potential to revolutionize genomics. The rational design of pores with the controlled polymer translocation rates and high contrast between different nucleotides could improve significantly nanopore sequencing applications. Here, we apply a combination of theoretical and experimental methods in an attempt to elucidate several selective modifications in the pore which were proposed to be central for the effective discrimination between purines and pyrimidines. Our nanopore test set includes the wild type αHL and six mutants (E111N/M113X/K147N) in which the cross-section and chemical functionality of the first constriction zone of the pore are modified. Electrophysiological recordings were combined with all-atom Molecular Dynamics simulations (MD) and a recently developed Brownian Dynamics (BROMOC) protocol to investigate residual ion currents and pore-DNA interactions for two homo-polymers e.g. poly(dA)40 or poly(dC)40 blocking the pore. The calculated residual currents and contrast in the poly(dA)40/poly(dC)40 blocked pore are in qualitative agreement with the experimental recordings. We showed that a simple structural metric allows rationalization of key elements in the emergent contrast between purines and pyrimidines in the modified αHL mutants. The shape of the pore and its capacity for hydrogen bonding to a translocated polynucleotide are two essential parameters for contrast optimization. To further probe the impact of these two factors in the ssDNA sensing, we eliminated the effect of the primary constriction using serine substitutions (i.e. E111S/M113S/T145S/K147S) and increased the hydrophobic volume of the central residue in the secondary constriction (L135I). This pore modification sharply increased the contrast between Adenine (A) and Cytosine (C).The electrophoretic transport of single

  17. Parallel Handling of Integrity Constraints

    NARCIS (Netherlands)

    Grefen, P.W.P.J.; Flokstra, Jan; Apers, Peter M.G.

    1990-01-01

    Integrity constraints form an important part of a data model. Therefore, a complete integrity constraint handling subsystem is considered an important part of any modern DBMS. In implementing an integrity constraint handling subsystem, there are two major problem areas: providing enough functionalit

  18. Constraints on the Cosmological Parameters using CMB observations

    OpenAIRE

    Rocha, Graca

    1999-01-01

    This paper covers several techniques of intercomparison of Cosmic Microwave Background (CMB) anisotropy experiments and models of structure formation. It presents the constraints on several cosmological parameters using current CMB observations.

  19. Statistical and Energetic Constraints in Population Synthesis Models

    CERN Document Server

    Buzzoni, A

    1998-01-01

    Physical and numerical constraints in building up self-consistent population synthesis models are briefly analysed discussing their application to most of the current synthesis codes widely adopted in Galactic and extragalactic studies.

  20. Transcranial direct current stimulation (tDCS) priming of 1Hz repetitive transcranial magnetic stimulation (rTMS) modulates experimental pain thresholds.

    Science.gov (United States)

    Moloney, Tonya M; Witney, Alice G

    2013-02-08

    Transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS) of primary motor cortex (M1) modulate cortical excitability. Both techniques have been demonstrated to modulate chronic pain and experimental pain thresholds, but with inconsistent effects. Preconditioning M1 with weak tDCS (1mA) standardizes the effects of subsequent stimulation via rTMS on levels of cortical excitability. Here we examine whether 1Hz rTMS, primed with tDCS, could effectively standardize the modulation of pain thresholds. Thermal pain thresholds were determined using quantitative sensory testing (QST) of the palmar thenar of both hands in 12 healthy males pre and post tDCS - 1Hz rTMS over the hand area of the left M1. Cathodal tDCS preconditioning of 1Hz rTMS successfully reversed the normal suppressive effect of low frequency rTMS and effectively modulated cold and heat pain thresholds. Conversely, anodal tDCS - 1Hz rTMS led to a decrease in cold pain thresholds. Therefore, this study supports that preconditioning M1 using cathodal tDCS before subsequent stimulation via 1Hz rTMS facilitates the production of analgesia.

  1. Transcranial direct current stimulation over the opercular somatosensory region does not influence experimentally induced pain: a triple blind, sham-controlled study

    Science.gov (United States)

    Koyama, Soichiro; Nakagawa, Kei

    2017-01-01

    Transcranial magnetic stimulation (TMS) over the opercular somatosensory region (OP), which includes the secondary somatosensory cortex and the insular cortex, suppresses pain sensation. However, whether transcranial direct current stimulation (tDCS) over the OP has a similar effect on pain sensation remains unknown. We examined whether pain sensation would be suppressed by tDCS over the OP. Our experiment with a triple-blind, sham-controlled, crossover design involved 12 healthy participants. Participants were asked to rate their subjective pain intensity during and after three types of bihemispheric tDCS: right anodal/left cathodal OP tDCS, left anodal/right cathodal OP tDCS (2 mA, 12 min), and sham tDCS (15 s). Pain stimuli were alternately applied to the dorsum of each index finger using intraepidermal electrical stimulation. We observed no significant effect of tDCS over the OP on the perception of experimentally induced pain. Subjective pain intensity did not differ significantly between the three tDCS conditions. The present null results have crucial implications for the selection of optimal stimulation regions and parameters for clinical pain treatment. PMID:27984542

  2. 偏头痛实验动物模型的研究现状%The Current Research Situation of Experimental Animal Models of Migraine

    Institute of Scientific and Technical Information of China (English)

    袁博博

    2011-01-01

    偏头痛是一种由体外触发和体内病理生理机制相互作用、伴有神经心理及胃肠症状、具有遗传性及复发性的头痛综合征.其发病机制至今尚未完全明了,动物模型基于三叉神经血管学说、皮层扩散抑制学说和血管学说等理论而建立.现从造模机制、特点、适用范围及效度等方面对目前常用的偏头痛动物模型的研究现状进行综述.%Migraine is a genetically related recurrent headache syndrome appearing with neuro-psychological and gastrointestinal symptoms, implicating interaction between external triggers and internal pathophysiology. Its pathogenesis is still not completely clarified, animal models are established on the basis of trigeminovascular theory,cortical spreading depression theory and neurovascular theory. Here is to review the current migraine experimental animal models from the perspectives of modeling mechanism, characteristics,scope and validity, etc.

  3. Experimental study on the effects of surface gravity waves of different wavelengths on the phase averaged performance characteristics of marine current turbine

    Science.gov (United States)

    Luznik, L.; Lust, E.; Flack, K. A.

    2014-12-01

    There are few studies describing the interaction between marine current turbines and an overlying surface gravity wave field. In this work we present an experimental study on the effects of surface gravity waves of different wavelengths on the wave phase averaged performance characteristics of a marine current turbine model. Measurements are performed with a 1/25 scale (diameter D=0.8m) two bladed horizontal axis turbine towed in the large (116m long) towing tank at the U.S. Naval Academy equipped with a dual-flap, servo-controlled wave maker. Three regular waves with wavelengths of 15.8, 8.8 and 3.9m with wave heights adjusted such that all waveforms have the same energy input per unit width are produced by the wave maker and model turbine is towed into the waves at constant carriage speed of 1.68 m/s. This representing the case of waves travelling in the same direction as the mean current. Thrust and torque developed by the model turbine are measured using a dynamometer mounted in line with the turbine shaft. Shaft rotation speed and blade position are measured using in in-house designed shaft position indexing system. The tip speed ratio (TSR) is adjusted using a hysteresis brake which is attached to the output shaft. Free surface elevation and wave parameters are measured with two optical wave height sensors, one located in the turbine rotor plane and other one diameter upstream of the rotor. All instruments are synchronized in time and data is sampled at a rate of 700 Hz. All measured quantities are conditionally sampled as a function of the measured surface elevation and transformed to wave phase space using the Hilbert Transform. Phenomena observed in earlier experiments with the same turbine such as phase lag in the torque signal and an increase in thrust due to Stokes drift are examined and presented with the present data as well as spectral analysis of the torque and thrust data.

  4. EXPERIMENTAL RESEARCHES OF ELECTRO-THERMAL RESISTIBILITY OF SEND-OFFS AND CABLES TO ACTION RATIONED ON THE INTERNATIONAL STANDARD OF IEC 62305-1-2010 OF APERIODIC IMPULSE OF CURRENT OF ARTIFICIAL LIGHTNING

    OpenAIRE

    M.I. Baranov; Rudakov, S. V.

    2016-01-01

    Purpose. Experimental researches of electro-thermal resistibility of cable-explorer products, applied in the power electric circuits of objects of electric-power industry, to action on its copper and aluminum parts bearings a current rationed on the International Standard of IEC 62305-1-2010 aperiodic impulse 10/350 μs of current of artificial lightning. Methodology. Electrophysics bases of technique of high tensions and high pulsed currents (HPC), and also scientific and technical bases of p...

  5. Comparing Constraints from Dark Matter Studies to Invisible Higgs Searches at CMS

    CERN Document Server

    Mccusker, Daniel

    2016-01-01

    Evidence for dark matter constitutes a strong motivation for searches for physics beyond the Standard Model (BSM). Current dark matter experiments strongly constrain the regions of parameter space in which dark matter particles might reside. These constraints guide searches for dark matter through production channels at collider experiments, e.g. at the Large Hadron Collider (LHC). Using MadDM and MadGraph software, we conduct computational analyses on a simple Higgs portal model, in which a Standard Model (SM) Higgs boson decays to two scalar dark matter particles. We synthesize existing experimental constraints, from relic density and direct detection data, with estimates of the Higgs to invisible decay branching ratios at the LHC. We find a region of dark matter particle mass and Yukawa coupling values which may fall within the future plans for the detection capability of the HL-LHC.

  6. Markerless human motion capture by Markov random field and dynamic graph cuts with color constraints

    Institute of Scientific and Technical Information of China (English)

    LI Jia; WAN ChengKai; ZHANG DianYong; MIAO ZhenJiang; YUAN BaoZong

    2009-01-01

    Currently, many vision-based motion capture systems require passive markers attached to key lca-tions on the human body. However, such systems are intrusive with limited application. The algorithm that we use for human motion capture in this paper is based on Markov random field (MRF) and dynamic graph cuts. It takes full account of the impact of 3D reconstruction error and integrates human motion capture and 3D reconstruction into MRF-MAP framework. For more accurate and robust performance, we extend our algorithm by incorporating color constraints Into the pose estimation process. The ad-vantages of incorporating color constraints are demonstrated by experimental results on several video sequences.

  7. Constraints on field theoretical models for variation of the fine structure constant

    Science.gov (United States)

    Steinhardt, Charles L.

    2005-02-01

    Recent theoretical ideas and observational claims suggest that the fine structure constant α may be variable. We examine a spectrum of models in which α is a function of a scalar field. Specifically, we consider three scenarios: oscillating α, monotonic time variation of α, and time-independent α that is spatially varying. We examine the constraints imposed upon these theories by cosmological observations, particle detector experiments, and “fifth force” experiments. These constraints are very strong on models involving oscillation but cannot compete with bounds from the Oklo subnuclear reactor on models with monotonic timelike variation of α. One particular model with spatial variation is consistent with all current experimental and observational measurements, including those from two seemingly conflicting measurements of the fine structure constant using the many multiplet method on absorption lines.

  8. Direct and indirect constraints on CP-violating Higgs-quark and Higgs-gluon interactions

    CERN Document Server

    Chien, Y -T; Dekens, W; de Vries, J; Mereghetti, E

    2015-01-01

    We investigate direct and indirect constraints on the complete set of anomalous CP-violating Higgs couplings to quarks and gluons originating from dimension-6 operators, by studying their signatures at the LHC and in electric dipole moments (EDMs). We show that existing uncertainties in hadronic and nuclear matrix elements have a significant impact on the interpretation of EDM experiments, and we quantify the improvements needed to fully exploit the power of EDM searches. Currently, the best bounds on the anomalous CP-violating Higgs interactions come from a combination of EDM measurements and the data from LHC Run 1. We argue that Higgs production cross section measurements at the LHC Run 2 will not improve the constraints significantly. On the other hand, the bounds on the couplings scale roughly linearly with EDM limits, so that future theoretical and experimental EDM developments can have a major impact in pinning down interactions of the Higgs.

  9. Asteroseismic constraints for Gaia

    CERN Document Server

    Creevey, O L

    2012-01-01

    Distances from the Gaia mission will no doubt improve our understanding of stellar physics by providing an excellent constraint on the luminosity of the star. However, it is also clear that high precision stellar properties from, for example, asteroseismology, will also provide a needed input constraint in order to calibrate the methods that Gaia will use, e.g. stellar models or GSP_phot. For solar-like stars (F, G, K IV/V), asteroseismic data delivers at the least two very important quantities: (1) the average large frequency separation and (2) the frequency corresponding to the maximum of the modulated-amplitude spectrum nu_max. Both of these quantities are related directly to stellar parameters (radius and mass) and in particular their combination (gravity and density). We show how the precision in , nu_max, and atmospheric parameters T_eff and [Fe/H] affect the determination of gravity (log g) for a sample of well-known stars. We find that log g can be determined within less than 0.02 dex accuracy for ou...

  10. Design with Nonlinear Constraints

    KAUST Repository

    Tang, Chengcheng

    2015-12-10

    Most modern industrial and architectural designs need to satisfy the requirements of their targeted performance and respect the limitations of available fabrication technologies. At the same time, they should reflect the artistic considerations and personal taste of the designers, which cannot be simply formulated as optimization goals with single best solutions. This thesis aims at a general, flexible yet e cient computational framework for interactive creation, exploration and discovery of serviceable, constructible, and stylish designs. By formulating nonlinear engineering considerations as linear or quadratic expressions by introducing auxiliary variables, the constrained space could be e ciently accessed by the proposed algorithm Guided Projection, with the guidance of aesthetic formulations. The approach is introduced through applications in different scenarios, its effectiveness is demonstrated by examples that were difficult or even impossible to be computationally designed before. The first application is the design of meshes under both geometric and static constraints, including self-supporting polyhedral meshes that are not height fields. Then, with a formulation bridging mesh based and spline based representations, the application is extended to developable surfaces including origami with curved creases. Finally, general approaches to extend hard constraints and soft energies are discussed, followed by a concluding remark outlooking possible future studies.

  11. Experimental investigation of droplet separation in a horizontal counter-current air/water stratified flow; Experimentelle Untersuchung der Tropfenabscheidung einer horizontalen, entgegengerichteten Wasser/Luft-Schichtenstroemung

    Energy Technology Data Exchange (ETDEWEB)

    Gabriel, Stephan Gerhard

    2015-07-01

    A stratified counter-current two-phase gas/liquid flow can occur in various technical systems. In the past investigations have mainly been motivated by the possible occurrence of these flows in accident scenarios of nuclear light water-reactors and in numerous applications in process engineering. However, the precise forecast of flow parameters, is still challenging, for instance due to their strong dependency on the geometric boundary conditions. A new approach which uses CFD methods (Computational Fluid Dynamics) promises a better understanding of the flow phenomena and simultaneously a higher scalability of the findings. RANS methods (Reynolds Averaged Navier Stokes) are preferred in order to compute industrial processes and geometries. A very deep understanding of the flow behavior and equation systems based on real physics are necessary preconditions to develop the equation system for a reliable RANS approach with predictive power. Therefore, local highly resolved, experimental data is needed in order to provide and validate the required turbulence and phase interaction models. The central objective of this work is to provide the data needed for the code development for these unsteady, turbulent and three-dimensional flows. Experiments were carried out at the WENKA facility (Water Entrainment Channel Karlsruhe) at the Karlsruhe Institute of Technology (KIT). The work consists of a detailed description of the test-facility including a new bended channel, the measurement techniques and the experimental results. The characterization of the new channel was done by flow maps. A high-speed imaging study gives an impression of the occurring flow regimes, and different flow phenomena like droplet separation. The velocity distributions as well as various turbulence values were investigated by particle image velocimetry (PIV). In the liquid phase fluorescent tracer-particles were used to suppress optical reflections from the phase surface (fluorescent PIV, FPIV

  12. Distribution system constraints and their impact on distributed generation: final report

    Energy Technology Data Exchange (ETDEWEB)

    Thornycroft, J.; Caisley, A.; Russell, T.; Willis, S.; Youssef, R.; Bawden, R.; Holden, G.; Williams, J.

    2004-05-01

    This report examines constraints due to the connection of distributed generators to the distribution network focusing on small generators with the aim of developing technical and economic models to examine the relationship between the initial investment and the ensuing cost of the constraints under different scenarios. Constraints are defined as limitations to operation of connected generators, and the types of constraints, and the allocation of reinforcement and constraint costs are considered. Details are given of the modeling of sections of urban, rural and semi-rural network at Faversham, and the current constraints on this network are described.

  13. Constraints on Neutrino Mass from Galaxy Surveys

    Science.gov (United States)

    Cuesta, A. J.; Niro, V.; Verde, L.

    2017-03-01

    Modern large-scale galaxy surveys, combined with measurements of the cosmic microwave background, have managed to constrain the sum of neutrino masses to an order of magnitude below the limit placed by laboratory experiments. We discuss the signature of massive neutrinos in the distribution of galaxies and the current state of the art of neutrino mass constraints, focusing on parameter degeneracies that reveal how we can improve current constraints with next-generation galaxy surveys. We also comment on how the near future cosmology experiments are an opportunity for the first measurement of the value of the sum of neutrino masses, or alternatively, to find profound implications for neutrino physics extensions beyond the Standard Model.

  14. New Physics constraints from rare b → s + (γ, ℓ+ℓ− decays

    Directory of Open Access Journals (Sweden)

    Bobeth Christoph

    2013-05-01

    Full Text Available The experimental measurements of flavor-changing neutral-current B-meson decays governed by b → s + (γ, ℓ+ℓ− transitions have entered a new level of precision. Recent results by Belle, CDF, Babar, and LHCb on B → K(*ℓ+ℓ− and Bs → μ+μ− decays are used in model-(independent analyses to test the Standard Model predictions and to derive stronger constraints on nonstandard contributions. While in agreement with the Standard Model, they still leave sizable room for new physics.

  15. Robust adaptive matched field processing with sector eigenvector constraints

    Institute of Scientific and Technical Information of China (English)

    YANG Kunde; MA Yuanliang

    2006-01-01

    Standard adaptive beamforming or matched field processing requires accurate replica fields finely gridded over the search parameter space for localization with sidelobe control. This paper presents an Adaptive Matched Field Processing (AMFP) algo rithm, which aims at gaining robustness for the environmentai mismatch, and simultaneously reducing the real-time computational load. The new method integrates the merits of several AMFP beamformers with neighboring location constraints, environmental perturbation constraints and sector focusing constraints. The robustness and effectiveness of the suggested algorithm has been illustrated through the numerical simulation and the experimental Mediterranean benchmark shallow-water data.

  16. Rewriting Constraint Models with Metamodels

    CERN Document Server

    Chenouard, Raphael; Soto, Ricardo

    2010-01-01

    An important challenge in constraint programming is to rewrite constraint models into executable programs calculat- ing the solutions. This phase of constraint processing may require translations between constraint programming lan- guages, transformations of constraint representations, model optimizations, and tuning of solving strategies. In this paper, we introduce a pivot metamodel describing the common fea- tures of constraint models including different kinds of con- straints, statements like conditionals and loops, and other first-class elements like object classes and predicates. This metamodel is general enough to cope with the constructions of many languages, from object-oriented modeling languages to logic languages, but it is independent from them. The rewriting operations manipulate metamodel instances apart from languages. As a consequence, the rewriting operations apply whatever languages are selected and they are able to manage model semantic information. A bridge is created between the metamode...

  17. Constraint Propagation as Information Maximization

    CERN Document Server

    Abdallah, A Nait

    2012-01-01

    Dana Scott used the partial order among partial functions for his mathematical model of recursively defined functions. He interpreted the partial order as one of information content. In this paper we elaborate on Scott's suggestion of regarding computation as a process of information maximization by applying it to the solution of constraint satisfaction problems. Here the method of constraint propagation can be interpreted as decreasing uncertainty about the solution -- that is, as gain in information about the solution. As illustrative example we choose numerical constraint satisfaction problems to be solved by interval constraints. To facilitate this approach to constraint solving we formulate constraint satisfaction problems as formulas in predicate logic. This necessitates extending the usual semantics for predicate logic so that meaning is assigned not only to sentences but also to formulas with free variables.

  18. Efficient Searching with Linear Constraints

    DEFF Research Database (Denmark)

    Agarwal, Pankaj K.; Arge, Lars Allan; Erickson, Jeff

    2000-01-01

    We show how to preprocess a set S of points in d into an external memory data structure that efficiently supports linear-constraint queries. Each query is in the form of a linear constraint xd a0+∑d−1i=1 aixi; the data structure must report all the points of S that satisfy the constraint. This pr......We show how to preprocess a set S of points in d into an external memory data structure that efficiently supports linear-constraint queries. Each query is in the form of a linear constraint xd a0+∑d−1i=1 aixi; the data structure must report all the points of S that satisfy the constraint...

  19. Constraints On Cosmic Dynamics

    CERN Document Server

    Mbonye, M R

    2003-01-01

    Observationally, the universe appears virtually critical. Yet, there is no simple explanation for this state. In this article we advance and explore the premise that the dynamics of the universe always seeks equilibrium conditions. Vacuum-induced cosmic accelerations lead to creation of matter-energy modes at the expense of vacuum energy. Because they gravitate, such modes constitute inertia against cosmic acceleration. On the other extreme, the would-be ultimate phase of local gravitational collapse is checked by a phase transition in the collapsing matter fields leading to a de Sitter-like fluid deep inside the black hole horizon, and at the expense of the collapsing matter fields. As a result, the universe succumbs to neither vacuum-induced run-away accelerations nor to gravitationally induced spacetime curvature singularities. Cosmic dynamics is self-regulating. We discuss the physical basis for these constraints and the implications, pointing out how the framework relates and helps resolve standing puzzl...

  20. Constraints on Spontaneous Entrainment

    Directory of Open Access Journals (Sweden)

    Richardson Michael J.

    2011-12-01

    Full Text Available Past research has revealed that a person's rhythmic limb movements become spontaneously entrained to an environmental rhythm if a. visual information about the environmental rhythm is available and b. its frequency of the environmental rhythm is near that of the person's movements. Further, this research has demonstrated that if the eyes track the environmental stimulus, the spontaneous entrainment to the environmental rhythm is strengthened. Experiments were performed to investigate two hypotheses that could explain this eye-tracking enhancement of spontaneous entrainment. One hypothesis is that eye tracking allows for the pick up of important coordinative information at the turn-around points of a movement trajectory. Another hypothesis is that the limb movements entrain to the moving eyes through a neuromotor synergy linking the eyes and limb. Results of these experiments will help delineate the informational and dynamical constraints that can impact the acquisition of skilled actions.

  1. Constraint-Based Categorial Grammar

    CERN Document Server

    Bouma, G; Bouma, Gosse; Noord, Gertjan van

    1994-01-01

    We propose a generalization of Categorial Grammar in which lexical categories are defined by means of recursive constraints. In particular, the introduction of relational constraints allows one to capture the effects of (recursive) lexical rules in a computationally attractive manner. We illustrate the linguistic merits of the new approach by showing how it accounts for the syntax of Dutch cross-serial dependencies and the position and scope of adjuncts in such constructions. Delayed evaluation is used to process grammars containing recursive constraints.

  2. Seismological Constraints on Geodynamics

    Science.gov (United States)

    Lomnitz, C.

    2004-12-01

    Earth is an open thermodynamic system radiating heat energy into space. A transition from geostatic earth models such as PREM to geodynamical models is needed. We discuss possible thermodynamic constraints on the variables that govern the distribution of forces and flows in the deep Earth. In this paper we assume that the temperature distribution is time-invariant, so that all flows vanish at steady state except for the heat flow Jq per unit area (Kuiken, 1994). Superscript 0 will refer to the steady state while x denotes the excited state of the system. We may write σ 0=(J{q}0ṡX{q}0)/T where Xq is the conjugate force corresponding to Jq, and σ is the rate of entropy production per unit volume. Consider now what happens after the occurrence of an earthquake at time t=0 and location (0,0,0). The earthquake introduces a stress drop Δ P(x,y,z) at all points of the system. Response flows are directed along the gradients toward the epicentral area, and the entropy production will increase with time as (Prigogine, 1947) σ x(t)=σ 0+α {1}/(t+β )+α {2}/(t+β )2+etc A seismological constraint on the parameters may be obtained from Omori's empirical relation N(t)=p/(t+q) where N(t) is the number of aftershocks at time t following the main shock. It may be assumed that p/q\\sim\\alpha_{1}/\\beta times a constant. Another useful constraint is the Mexican-hat geometry of the seismic transient as obtained e.g. from InSAR radar interferometry. For strike-slip events such as Landers the distribution of \\DeltaP is quadrantal, and an oval-shaped seismicity gap develops about the epicenter. A weak outer triggering maxiμm is found at a distance of about 17 fault lengths. Such patterns may be extracted from earthquake catalogs by statistical analysis (Lomnitz, 1996). Finally, the energy of the perturbation must be at least equal to the recovery energy. The total energy expended in an aftershock sequence can be found approximately by integrating the local contribution over

  3. Minimal Flavor Constraints for Technicolor

    DEFF Research Database (Denmark)

    Sakuma, Hidenori; Sannino, Francesco

    2010-01-01

    We analyze the constraints on the the vacuum polarization of the standard model gauge bosons from a minimal set of flavor observables valid for a general class of models of dynamical electroweak symmetry breaking. We will show that the constraints have a strong impact on the self-coupling and mas...

  4. Nonholonomic constraints with fractional derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Tarasov, Vasily E [Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119992 (Russian Federation); Zaslavsky, George M [Courant Institute of Mathematical Sciences, New York University, 251 Mercer St, New York, NY 10012 (United States)

    2006-08-04

    We consider the fractional generalization of nonholonomic constraints defined by equations with fractional derivatives and provide some examples. The corresponding equations of motion are derived using variational principle. We prove that fractional constraints can be used to describe the evolution of dynamical systems in which some coordinates and velocities are related to velocities through a power-law memory function.

  5. Market segmentation using perceived constraints

    Science.gov (United States)

    Jinhee Jun; Gerard Kyle; Andrew Mowen

    2008-01-01

    We examined the practical utility of segmenting potential visitors to Cleveland Metroparks using their constraint profiles. Our analysis identified three segments based on their scores on the dimensions of constraints: Other priorities--visitors who scored the highest on 'other priorities' dimension; Highly Constrained--visitors who scored relatively high on...

  6. On Constraints in Assembly Planning

    Energy Technology Data Exchange (ETDEWEB)

    Calton, T.L.; Jones, R.E.; Wilson, R.H.

    1998-12-17

    Constraints on assembly plans vary depending on product, assembly facility, assembly volume, and many other factors. Assembly costs and other measures to optimize vary just as widely. To be effective, computer-aided assembly planning systems must allow users to express the plan selection criteria that appIy to their products and production environments. We begin this article by surveying the types of user criteria, both constraints and quality measures, that have been accepted by assembly planning systems to date. The survey is organized along several dimensions, including strategic vs. tactical criteria; manufacturing requirements VS. requirements of the automated planning process itself and the information needed to assess compliance with each criterion. The latter strongly influences the efficiency of planning. We then focus on constraints. We describe a framework to support a wide variety of user constraints for intuitive and efficient assembly planning. Our framework expresses all constraints on a sequencing level, specifying orders and conditions on part mating operations in a number of ways. Constraints are implemented as simple procedures that either accept or reject assembly operations proposed by the planner. For efficiency, some constraints are supplemented with special-purpose modifications to the planner's algorithms. Fast replanning enables an interactive plan-view-constrain-replan cycle that aids in constraint discovery and documentation. We describe an implementation of the framework in a computer-aided assembly planning system and experiments applying the system to a number of complex assemblies, including one with 472 parts.

  7. Constraint Programming for Context Comprehension

    DEFF Research Database (Denmark)

    Christiansen, Henning

    2014-01-01

    of knowledge. The language of Constraint Handling Rules, CHR, is suggested for defining constraint solvers that reflect “world knowledge” for the given domain, and driver algorithms may be ex- pressed in Prolog or additional rules of CHR. It is argued that this way of doing context comprehension is an instance...

  8. Redshift drift constraints on holographic dark energy

    Science.gov (United States)

    He, Dong-Ze; Zhang, Jing-Fei; Zhang, Xin

    2017-03-01

    The Sandage-Loeb (SL) test is a promising method for probing dark energy because it measures the redshift drift in the spectra of Lyman- α forest of distant quasars, covering the "redshift desert" of 2 ≲ z ≲ 5, which is not covered by existing cosmological observations. Therefore, it could provide an important supplement to current cosmological observations. In this paper, we explore the impact of SL test on the precision of cosmological constraints for two typical holographic dark energy models, i.e., the original holographic dark energy (HDE) model and the Ricci holographic dark energy (RDE) model. To avoid data inconsistency, we use the best-fit models based on current combined observational data as the fiducial models to simulate 30 mock SL test data. The results show that SL test can effectively break the existing strong degeneracy between the present-day matter density Ωm0 and the Hubble constant H 0 in other cosmological observations. For the considered two typical dark energy models, not only can a 30-year observation of SL test improve the constraint precision of Ωm0 and h dramatically, but can also enhance the constraint precision of the model parameters c and α significantly.

  9. HUBBLE PARAMETER MEASUREMENT CONSTRAINTS ON DARK ENERGY

    Energy Technology Data Exchange (ETDEWEB)

    Farooq, Omer; Mania, Data; Ratra, Bharat, E-mail: omer@phys.ksu.edu, E-mail: mania@phys.ksu.edu, E-mail: ratra@phys.ksu.edu [Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, KS 66506 (United States)

    2013-02-20

    We use 21 Hubble parameter versus redshift data points from Simon et al., Gaztanaga et al., Stern et al., and Moresco et al. to place constraints on model parameters of constant and time-evolving dark energy cosmologies. The inclusion of the eight new measurements results in H(z) constraints more restrictive than those derived by Chen and Ratra. These constraints are now almost as restrictive as those that follow from current Type Ia supernova (SNIa) apparent magnitude versus redshift data, which now more carefully account for systematic uncertainties. This is a remarkable result. We emphasize, however, that SNIa data have been studied for a longer time than the H(z) data, possibly resulting in a better estimate of potential systematic errors in the SNIa case. A joint analysis of the H(z), baryon acoustic oscillation peak length scale, and SNIa data favors a spatially flat cosmological model currently dominated by a time-independent cosmological constant but does not exclude slowly evolving dark energy.

  10. 强约束轴心受压钢管柱耐火性能试验研究%Experimental study on the fire-resistance of steel tube columns with axial compression and strong constraints

    Institute of Scientific and Technical Information of China (English)

    屈立军; 潘翀; 李焕群

    2012-01-01

    为正确评估强约束钢管柱的耐火性能,利用自行研制的杆系结构构件温度轴力测量装置,采用恒载升温试验方法,设5级初应力水平,6种长细比,对30根Q345钢管柱进行试验研究,揭示轴心受压钢管柱在强约束下的耐火性能。试验结果表明:强约束钢管柱在温升作用下的温度应力相当大,对钢管柱破坏有决定性作用,在耐火设计与评估中必须考虑。钢管柱在高温作用下,破坏前其弹塑性性质较为明显。相同长细比的构件,在较高的初始应力水平作用下,极限承载力大、温度应力小、临界温度低;反之相反。在相同初应力水平下,长细比对强约束钢管柱的极限承载力和温度应力的影响并不敏感,但长细比大的试件为失稳破坏,破坏后变形很大;长细比较小的试件为强度破坏,破坏后变形较小。以试验数据为基础给出两端固定Q345钢管柱的下限临界温度回归计算公式,可用于火灾中约束刚度不变的钢结构耐火设计与评估。%In order to evaluate the fire resistance of steel tube columns with strong constraints, a self-developed thermal internal force measurement device for frame structure members was employed. Test under elevated temperature and constant loading was conducted for 30 steel tube columns of Q345 with 5 grades of initial stress levels and 6 slenderness ratios, to reveal the fire resistance of such columns. The results show that under elevated temperature the thermal stress of the steel tube columns is great, and should be considered in the fire resistance design and evaluation. Under elevated temperature, the steel tube columns exhibite obvious elasto-plastic properties before failure. With identical slenderness ratio, the columns with higher initial stress level hadve larger bearing capability, lower thermal stress and critical temperature, when compared with the columns with lower initial stress levels

  11. Hubble parameter data constraints on dark energy

    Energy Technology Data Exchange (ETDEWEB)

    Chen Yun, E-mail: chenyun@mail.bnu.edu.cn [Department of Astronomy, Beijing Normal University, Beijing 100875 (China); Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, KS 66506 (United States); Ratra, Bharat, E-mail: ratra@phys.ksu.edu [Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, KS 66506 (United States)

    2011-09-20

    We use Hubble parameter versus redshift data from Stern et al. (2010) and Gaztanaga et al. (2009) to place constraints on model parameters of constant and time-evolving dark energy cosmological models. These constraints are consistent with (through not as restrictive as) those derived from supernova Type Ia magnitude-redshift data. However, they are more restrictive than those derived from galaxy cluster angular diameter distance, and comparable with those from gamma-ray burst and lookback time data. A joint analysis of the Hubble parameter data with more restrictive baryon acoustic oscillation peak length scale and supernova Type Ia apparent magnitude data favors a spatially-flat cosmological model currently dominated by a time-independent cosmological constant but does not exclude time-varying dark energy.

  12. Atom-Interferometry Constraints on Dark Energy

    Science.gov (United States)

    Mueller, Holger

    2016-03-01

    If dark energy is a light scalar field, it might interact with normal matter. The interactions, however, are suppressed in some leading models, which are thus compatible with current cosmological observations as well as solar-system and laboratory studies. Such suppression typically relies on the scalar's interaction with macroscopic amounts of ordinary matter, but can be bypassed by studying the interaction with individual particles. Using an atom interferometer, we have placed tight constraints on so-called chameleon models, ruling out interaction parameters βM > 4 ×104 . This limit is improved by 2.5 orders of magnitude relative to previous experiments. We have already increased the sensitivity of our interferometer hundredfold and are expecting a new constraint soon. Purpose-built experiments in the lab or on the international space station will completely close the gap and rule out out chameleons and other theories, such as axions, dark photons, symmetrons or f (R) gravity.

  13. Examination and experimental constraints of the stellar reaction rate factor $N_A < \\sigma v >$ of the $^{18}$Ne($\\alpha$,$p$)$^{21}$Na reaction at temperatures of X-Ray Bursts

    CERN Document Server

    Mohr, P

    2013-01-01

    The $^{18}$Ne($\\alpha$,$p$)$^{21}$Na reaction is one key for the break-out from the hot CNO-cycles to the $rp$-process. Recent papers have provided reaction rate factors $N_A $ which are discrepant by at least one order of magnitude. The compatibility of the latest experimental results is tested, and a partial explanation for the discrepant $N_A$ is given. A new rate factor is derived from the combined analysis of all available data. The new rate factor is located slightly below the higher rate factor by Matic {\\it et al.}\\ at low temperatures and significantly below at higher temperatures whereas it is about a factor of five higher than the lower rate factor recently published by Salter {\\it et al.}

  14. Experimental and theoretical studies of a high temperature cesium-barium tacitron, with application to low voltage-high current inversion. Final report, April 1, 1993--February 28, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Murray, C.S.; El-Genk, M.S.

    1994-02-01

    A low voltage/high current switch refer-red as ``Cs-Ba tacitron`` is studied for use as a dc to ac inverter in high temperature and/or ionizing radiation environments. The operational characteristics of the Cs-Ba tacitron as a switch were investigated experimentally in three modes: (a) breakdown mode, (b) I-V mode, and (c) current modulation mode. Operation parameters measured include switching frequencies up to 20 kHz, hold-off voltages up to 200 V, current densities in excess of 15 A/CM{sup 2}, switch power density of 1 kW/cm{sup 2}, and a switching efficiency in excess of 90 % at collector voltages greater than 30 V. Also, if the discharge current is circuit limited to a value below the maximum thermal emission current density, the voltage drop is constant and below 3 V.

  15. Numerical evaluation of currents induced in a worker by ELF non-uniform electric fields in high voltage substations and comparison with experimental results.

    Science.gov (United States)

    Tarao, Hiroo; Korpinen, Leena H; Kuisti, Harri A; Hayashi, Noriyuki; Elovaara, Jarmo A; Isaka, Katsuo

    2013-01-01

    An ungrounded human, such as a substation worker, receives contact currents when touching a grounded object in electric fields. In this article, contact currents and internal electric fields induced in the human when exposed to non-uniform electric fields at 50 Hz are numerically calculated. This is done using a realistic human model standing at a distance of 0.1-0.5 m from the grounded conductive object. We found that the relationship between the external electric field strength and the contact current obtained by calculation is in good agreement with previous measurements. Calculated results show that the contact currents largely depend on the distance, and that the induced electric fields in the tissues are proportional to the contact current regardless of the non-uniformity of the external electric field. Therefore, it is concluded that the contact current, rather than the spatial average of the external electric field, is more suitable for evaluating electric field dosimetry of tissues. The maximum induced electric field appears in the spinal cord in the central nervous system tissues, with the induced electric field in the spinal cord approaching the basic restriction (100 mV/m) of the new 2010 International Commission on Non-Ionizing Radiation Protection guidelines for occupational exposure, if the contact current is 0.5 mA. Copyright © 2012 Wiley Periodicals, Inc.

  16. Ghost imaging lidar via sparsity constraints

    CERN Document Server

    Zhao, Chengqiang; Chen, Mingliang; Li, Enrong; Wang, Hui; Xu, Wendong; Han, Shensheng

    2012-01-01

    For remote sensing, high-resolution imaging techniques are helpful to catch more characteristic information of the target. We extend pseudo-thermal light ghost imaging to the area of remote imaging and propose a ghost imaging lidar system. For the first time, we demonstrate experimentally that the real-space image of a target at about 1.0 km range with 20 mm resolution is achieved by ghost imaging via sparsity constraints (GISC) technique. The characters of GISC technique compared to the existing lidar systems are also discussed.

  17. Evolutionary constraints or opportunities?

    Science.gov (United States)

    Sharov, Alexei A.

    2014-01-01

    Natural selection is traditionally viewed as a leading factor of evolution, whereas variation is assumed to be random and non-directional. Any order in variation is attributed to epigenetic or developmental constraints that can hinder the action of natural selection. In contrast I consider the positive role of epigenetic mechanisms in evolution because they provide organisms with opportunities for rapid adaptive change. Because the term “constraint” has negative connotations, I use the term “regulated variation” to emphasize the adaptive nature of phenotypic variation, which helps populations and species to survive and evolve in changing environments. The capacity to produce regulated variation is a phenotypic property, which is not described in the genome. Instead, the genome acts as a switchboard, where mostly random mutations switch “on” or “off” preexisting functional capacities of organism components. Thus, there are two channels of heredity: informational (genomic) and structure-functional (phenotypic). Functional capacities of organisms most likely emerged in a chain of modifications and combinations of more simple ancestral functions. The role of DNA has been to keep records of these changes (without describing the result) so that they can be reproduced in the following generations. Evolutionary opportunities include adjustments of individual functions, multitasking, connection between various components of an organism, and interaction between organisms. The adaptive nature of regulated variation can be explained by the differential success of lineages in macro-evolution. Lineages with more advantageous patterns of regulated variation are likely to produce more species and secure more resources (i.e., long-term lineage selection). PMID:24769155

  18. Semantic Segmentation with Same Topic Constraints

    Directory of Open Access Journals (Sweden)

    Ling Mao

    2013-02-01

    Full Text Available A popular approach to semantic segmentation problems is to construct a pair wise Conditional Markov Random Field (CRF over image pixels where the pair wise term encodes a preference for smoothness within pixel neighborhoods. Recently, researchers have considered higher-order models that encode local region or soft non-local constraints (e.g., label consistency or co-occurrence statistics. These new models with higher-order terms have significantly pushed the state-of-the-art for semantic segmentation problems. In this study, we consider a novel non-local constraint that enforces consistent pixel labels among those image regions having the same topic. These topics are discovered by Probabilistic Latent Semantic Analysis model (PLSA. We encode this constraint as a robust Pn higher-order potential among all the image regions of the same topic in a unified CRF model. We experimentally demonstrate quantitative and qualitative improvements over a refined baseline unary and pair wise CRF models.

  19. CONSTRAINT PROGRAMMING AND UNIVERSITY TIMETABLING

    Directory of Open Access Journals (Sweden)

    G.W. Groves

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: The technology of Constraint Programming is rapidly becoming a popular alternative for solving large-scale industry problems. This paper provides an introduction to Constraint Programming and to Constraint Logic Programming (CLP, an enabler of constraint programming. The use of Constraint Logic Programming is demonstrated by describing a system developed for scheduling university timetables. Timetabling problems have a high degree of algorithmic complexity (they are usually NP-Complete, and share features with scheduling problems encountered in industry. The system allows the declaration of both hard requirements, which must always be satisfied, and soft constraints which need not be satisfied, though this would be an advantage.

    AFRIKAANSE OPSOMMING: Hierdie artikel beskryf ’n familie van probleem-oplossingstegnieke bekend as “Constraint Programming”, wat al hoe meer gebruik word om groot-skaalse industriële probleme op te los. Die nut van hierdie tegnieke word gedemonstreer deur die beskrywing van ’n skeduleringsisteem om die roosters vir ’n universiteit te genereer. Roosterskeduleringsprobleme is in praktiese gevalle NP-volledig en deel baie eienskappe met industriële skeduleringsprobleme. Die sisteem wat hier beskryf word maak gebruik van beide harde beperkings (wat altyd bevredig moet word en sagte beperkings (bevrediging hiervan is wel voordelig maar dit is opsioneel.

  20. Dynamic active constraints for hyper-redundant flexible robots.

    Science.gov (United States)

    Kwok, Ka-Wai; Mylonas, George P; Sun, Loi Wah; Lerotic, Mirna; Clark, James; Athanasiou, Thanos; Darzi, Ara; Yang, Guang-Zhong

    2009-01-01

    In robot-assisted procedures, the surgeon's ability can be enhanced by navigation guidance through the use of virtual fixtures or active constraints. This paper presents a real-time modeling scheme for dynamic active constraints with fast and simple mesh adaptation under cardiac deformation and changes in anatomic structure. A smooth tubular pathway is constructed which provides assistance for a flexible hyper-redundant robot to circumnavigate the heart with the aim of undertaking bilateral pulmonary vein isolation as part of a modified maze procedure for the treatment of debilitating arrhythmia and atrial fibrillation. In contrast to existing approaches, the method incorporates detailed geometrical constraints with explicit manipulation margins of the forbidden region for an entire articulated surgical instrument, rather than just the end-effector itself. Detailed experimental validation is conducted to demonstrate the speed and accuracy of the instrument navigation with and without the use of the proposed dynamic constraints.

  1. An experimental study of impact loading on deck of shore-connecting jetties ex-posed to oblique waves and current

    Institute of Scientific and Technical Information of China (English)

    孟艳秋; 陈国平; 严士常; 童朝锋

    2014-01-01

    The impact pressure from waves is an important issue to be considered in the design of coastal structures. In this paper, the waves acting on the deck of a shore-connecting jetty on a slope exposed to oblique waves and in the presence of current are examined based on laboratory experiments. The impact pressures are measured on a 1:50 scale model of a jetty head with down-standing beams and berthing members. The relations of the impact pressure with the incident wave angle and the current velocity are examined. It is shown that the impact pressure is sensitive to the wave angle and the current velocity. A computational model for the impact load on the deck of shore-connecting jetties exposed to oblique waves and current is developed.

  2. Experimental Study of the Course of Threshold Current, Voltage and Electrode Impedance During Stepwise Stimulation From the Skin Surface to the Human Cortex

    NARCIS (Netherlands)

    Szelenyi, Andrea; Journee, Henricus Louis; Herrlich, Simon; Galistu, Gianni M.; van den Berg, Joris; van Dijk, J. Marc C.

    Background: Transcranial electric stimulation as used during intraoperative neurostimulation is dependent on electrode and skull impedances. Objective: Threshold currents, voltages and electrode impedances were evaluated with electrical stimulation at 8 successive layers between the skin and the

  3. Experimental Study of the Course of Threshold Current, Voltage and Electrode Impedance During Stepwise Stimulation From the Skin Surface to the Human Cortex

    NARCIS (Netherlands)

    Szelenyi, Andrea; Journee, Henricus Louis; Herrlich, Simon; Galistu, Gianni M.; van den Berg, Joris; van Dijk, J. Marc C.

    2013-01-01

    Background: Transcranial electric stimulation as used during intraoperative neurostimulation is dependent on electrode and skull impedances. Objective: Threshold currents, voltages and electrode impedances were evaluated with electrical stimulation at 8 successive layers between the skin and the cer

  4. Experimental constraints on the monazite-fluorapatite-allanite and xenotime-(Y,HREE)-rich fluorapatite-(Y,HREE)-rich epidote phase relations as a function of pressure, temperature, and Ca vs. Na activity in the fluid

    Science.gov (United States)

    Budzyń, Bartosz; Harlov, Daniel E.; Majka, Jarosław; Kozub, Gabriela A.

    2014-05-01

    Stability relations of monazite-fluorapatite-allanite and xenotime-(Y,HREE)-rich fluorapatite-(Y,HREE)-rich epidote are strongly dependent on pressure, temperature and fluid composition. The increased Ca bulk content expands stability field of allanite relative to monazite towards higher temperatures (Spear, 2010, Chem Geol 279, 55-62). It was also reported from amphibolite facies Alpine metapelites, that both temperature and bulk CaO/Na2O ratio control relative stabilities of allanite, monazite and xenotime (Janots et al., 2008, J Metam Geol 26, 5, 509-526). This study experimentally defines influence of pressure, temperature, high activity of Ca vs. Na in the fluid, and high vs. moderate bulk CaO/Na2O ratio on the relative stabilities of monazite-fluorapatite-allanite/REE-rich epidote and xenotime-(Y,HREE)-rich fluorapatite-(Y,HREE)-rich epidote. This work expands previous experimental study on monazite (Budzyń et al., 2011, Am Min 96, 1547-1567) to wide pressure-temperature range of 2-10 kbar and 450-750°C, utilizing most reactive fluids used in previous experiments. Experiments were performed using cold-seal autoclaves on a hydrothermal line (2-4 kbar runs) and piston-cylinder apparatus (6-10 kbar runs) over 4-16 days. Four sets of experiments, two for monazite and two for xenotime, were performed with 2M Ca(OH)2 and Na2Si2O5 + H2O fluids. The starting materials included inclusion-free crystals of monazite (pegmatite, Burnet County, TX, USA) or xenotime (pegmatite, Northwest Frontier Province, Pakistan) mixed with (1) labradorite (Ab37An60Kfs3) + K-feldspar + biotite + muscovite ± garnet + SiO2 + CaF2 + 2M Ca(OH)2 or (2) albite (Ab100) + K-feldspar + biotite + muscovite ± garnet + SiO2 + CaF2 + Na2Si2O5 + H2O. 20-35 mg of solids and 5 mg of fluid were loaded into 3x15 mm Au capsules and arc welded shut. The monazite alteration is observed in all runs. Newly formed REE-rich fluorapatite and/or britholite are stable in all experimental P-T range in the

  5. Decrease of a Current Mediated by K(v)1.3 Channels Causes Striatal Cholinergic Interneuron Hyperexcitability in Experimental Parkinsonism

    OpenAIRE

    Cecilia Tubert; Irene R.E. Taravini; Eden Flores-Barrera; Gonzalo M. Sánchez; María Alejandra Prost; María Elena Avale; Kuei Y. Tseng; Lorena Rela; Mario Gustavo Murer

    2016-01-01

    The mechanism underlying a hypercholinergic state in Parkinsons disease (PD) remains uncertain. Here, we show that disruption of the K(v)1 channel-mediated function causes hyperexcitability of striatal cholinergic interneurons in a mouse model of PD. Specifically, our data reveal that Kv1 channels containing K(v)1.3 subunits contribute significantly to the orphan potassium current known as I-sAHP in striatal cholinergic interneurons. Typically, this Kv1 current provides negative feedback to d...

  6. EXPERIMENTAL ESTIMATION OF THE ANALGESIC EFFECT AT COMBINED INFLUENCE OF THE ELECTROSTIMULATION AND THE PERCUSSIVE-FRICTIONAL MASSAGE AND IMPULSE CURRENTS REGISTRATION

    Directory of Open Access Journals (Sweden)

    M. G. Kiselev

    2012-01-01

    Full Text Available The experimental complex of percussive-frictional massager with electrostimulation function and softand hardware of original design gives a possibility to use various mechanical and electrical parameters of massage and electrostimulation and it can be used like the alternative instead of the accepted medicine analgesics. Analgesic effect decreases pain sensation of the patient up to 50 %.

  7. MODELING AND EXPERIMENTAL EVALUATION OF AN AEROSOL GENERATOR FOR VERY HIGH NUMBER CURRENTS BASED ON A FREE TURBULENT JET. (R827354C008)

    Science.gov (United States)

    In this paper we report on theoretical and experimental work on aerosol formation in a free turbulent jet. A hot DEHS vapor issues through a circular nozzle into slowly moving cold air. Vapor concentration and temperatures are such that particles are formed via homogeneous nuc...

  8. Effective Constraints for Quantum Systems

    CERN Document Server

    Bojowald, Martin; Skirzewski, Aureliano; Tsobanjan, Artur

    2008-01-01

    An effective formalism for quantum constrained systems is presented which allows manageable derivations of solutions and observables, including a treatment of physical reality conditions without requiring full knowledge of the physical inner product. Instead of a state equation from a constraint operator, an infinite system of constraint functions on the quantum phase space of expectation values and moments of states is used. The examples of linear constraints as well as the free non-relativistic particle in parameterized form illustrate how standard problems of constrained systems can be dealt with in this framework.

  9. Pose measurement method based on geometrical constraints

    Institute of Scientific and Technical Information of China (English)

    Zimiao Zhang; Changku Sun; Pengfei Sun; Peng Wang

    2011-01-01

    @@ The pose estimation method based on geometric constraints is studied.The coordinates of the five feature points in the camera coordinate system are calculated to obtain the pose of an object on the basis of the geometric constraints formed by the connective lines of the feature points and the coordinates of the feature points on the CCD image plane; during the solution process,the scaling and orthography projection model is used to approximate the perspective projection model.%The pose estimation method based on geometric constraints is studied. The coordinates of the five feature points in the camera coordinate system are calculated to obtain the pose of an object on the basis of the geometric constraints formed by the connective lines of the feature points and the coordinates of the feature points on the CCD image plane; during the solution process, the scaling and orthography projection model is used to approximate the perspective projection model. The initial values of the coordinates of the five feature points in the camera coordinate system are obtained to ensure the accuracy and convergence rate of the non-linear algorithm. In accordance with the perspective projection characteristics of the circular feature landmarks, we propose an approach that enables the iterative acquisition of accurate target poses through the correction of the perspective projection coordinates of the circular feature landmark centers. Experimental results show that the translation positioning accuracy reaches ±0.05 mm in the measurement range of 0-40 mm, and the rotation positioning accuracy reaches ±0.06° in the measurement range of 4°-60°.

  10. Mass Action and Conservation of Current

    Directory of Open Access Journals (Sweden)

    Eisenberg Robert S.

    2016-10-01

    Full Text Available The law of mass action does not force a series of chemical reactions to have the same current flow everywhere. Interruption of far-away current does not stop current everywhere in a series of chemical reactions (analyzed according to the law of mass action, and so does not obey Maxwell’s equations. An additional constraint and equation is needed to enforce global continuity of current. The additional constraint is introduced in this paper in the special case that the chemical reaction describes spatial movement through narrow channels. In that case, a fully consistent treatment is possible using different models of charge movement. The general case must be dealt with by variational methods that enforce consistency of all the physical laws involved. Violations of current continuity arise away from equilibrium, when current flows, and the law of mass action is applied to a non-equilibrium situation, different from the systems considered when the law was originally derived. Device design in the chemical world is difficult because simple laws are not obeyed in that way. Rate constants of the law of mass action are found experimentally to change from one set of conditions to another. The law of mass action is not robust in most cases and cannot serve the same role that circuit models do in our electrical technology. Robust models and device designs in the chemical world will not be possible until continuity of current is embedded in a generalization of the law of mass action using a consistent variational model of energy and dissipation.

  11. Phonotactic Constraints Are Activated across Languages in Bilinguals

    Science.gov (United States)

    Freeman, Max R.; Blumenfeld, Henrike K.; Marian, Viorica

    2016-01-01

    During spoken language comprehension, auditory input activates a bilingual’s two languages in parallel based on phonological representations that are shared across languages. However, it is unclear whether bilinguals access phonotactic constraints from the non-target language during target language processing. For example, in Spanish, words with s+ consonant onsets cannot exist, and phonotactic constraints call for epenthesis (addition of a vowel, e.g., stable/estable). Native Spanish speakers may produce English words such as estudy (“study”) with epenthesis, suggesting that these bilinguals apply Spanish phonotactic constraints when speaking English. The present study is the first to examine whether bilinguals access Spanish phonotactic constraints during English comprehension. In an English cross-modal priming lexical decision task, Spanish–English bilinguals and English monolinguals heard English cognate and non-cognate primes containing s+ consonant onsets or controls without s+ onsets, followed by a lexical decision on visual targets with the /e/ phonotactic constraint or controls without /e/. Results revealed that bilinguals were faster to respond to /es/ non-word targets preceded by s+ cognate primes and /es/ and /e/ non-word targets preceded by s+ non-cognate primes, confirming that English primes containing s+ onsets activated Spanish phonotactic constraints. These findings are discussed within current accounts of parallel activation of two languages during bilingual spoken language comprehension, which may be expanded to include activation of phonotactic constraints from the irrelevant language. PMID:27242615

  12. Weighted constraints in generative linguistics.

    Science.gov (United States)

    Pater, Joe

    2009-08-01

    Harmonic Grammar (HG) and Optimality Theory (OT) are closely related formal frameworks for the study of language. In both, the structure of a given language is determined by the relative strengths of a set of constraints. They differ in how these strengths are represented: as numerical weights (HG) or as ranks (OT). Weighted constraints have advantages for the construction of accounts of language learning and other cognitive processes, partly because they allow for the adaptation of connectionist and statistical models. HG has been little studied in generative linguistics, however, largely due to influential claims that weighted constraints make incorrect predictions about the typology of natural languages, predictions that are not shared by the more popular OT. This paper makes the case that HG is in fact a promising framework for typological research, and reviews and extends the existing arguments for weighted over ranked constraints.

  13. Model-Driven Constraint Programming

    CERN Document Server

    Chenouard, Raphael; Soto, Ricardo; 10.1145/1389449.1389479

    2010-01-01

    Constraint programming can definitely be seen as a model-driven paradigm. The users write programs for modeling problems. These programs are mapped to executable models to calculate the solutions. This paper focuses on efficient model management (definition and transformation). From this point of view, we propose to revisit the design of constraint-programming systems. A model-driven architecture is introduced to map solving-independent constraint models to solving-dependent decision models. Several important questions are examined, such as the need for a visual highlevel modeling language, and the quality of metamodeling techniques to implement the transformations. A main result is the s-COMMA platform that efficiently implements the chain from modeling to solving constraint problems

  14. Decentralized systems with design constraints

    CERN Document Server

    Mahmoud, Magdi S

    2014-01-01

    This volume provides a rigorous examination of the analysis, stability and control of large-scale systems, and addresses the difficulties that arise because of dimensionality, information structure constraints, parametric uncertainty and time-delays.

  15. Experimental analysis of current conduction through thermally grown SiO2 on thick epitaxial 4H-SiC employing Poole–Frenkel mechanism

    Indian Academy of Sciences (India)

    Sanjeev K Gupta; A Azam; J Akhtar

    2010-02-01

    Electrical properties of SiO2 grown on the Si-face of the epitaxial 4H-SiC substrate by wet thermal oxidation technique have been experimentally investigated in metal oxide–silicon carbide (MOSiC) structure with varying oxide thicknesses employing Poole–Frenkel (P–F) conduction mechanism. The quality of SiO2 with increasing thickness in MOSiC structure has been analysed on the basis of variation in multiple oxide traps due to effective P–F conduction range. Validity of Poole–Frenkel conduction is established quantitatively employing electric field and the oxide thickness using forward – characteristics across MOSiC structures. From P–F conduction plot (ln(/) vs. 1/2), it is revealed that Poole–Frenkel conduction retains its validation after a fixed electric field range. The experimental methodology adopted is useful for the characterization of oxide films grown on 4H-SiC substrate.

  16. Constraints on the parameters of the $V_{CKM}$ matrix at the end of 1997

    CERN Document Server

    Parodi, F; Stocchi, A

    1998-01-01

    A review of the current status of the Cabibbo-Kobayashi-Maskawa matrix V_CKM is presented. This paper contains an update of the results published in hep-ph/9711261. Values of the parameters entering into the constraints, which restrict the range for rho and eta parameters, include recent measurements given at 1997 Summer Conferences and progress obtained by lattice QCD collaborations.Experimental constraints imposed by the measurements of epsilon_k,V_ub/V_cb, Delta m_d and by the limit on Delta m_s, are compatible and do not show evidence for New Physics inside measurements errors. Values for the angles alpha, beta and gamma of the C.K.M. triangle have been also obtained: rho=0.156 +- 0.090 , eta=0.328 +- 0.054 sin 2alpha = -0.10+-0.40 ,sin 2beta = 0.68 +- 0.10 ,gamma= 64+-12¡ Angles theta,theta_u,theta_d and phi proposed in the parametrisation (Phys. Lett. B5353 (1995) 114.) of the C.K.M. matrix have been also determined. Finally, as there are more constraints than the fitted rho and eta parameters, several...

  17. Constraint Programming for Context Comprehension

    DEFF Research Database (Denmark)

    Christiansen, Henning

    2014-01-01

    A close similarity is demonstrated between context comprehension, such as discourse analysis, and constraint programming. The constraint store takes the role of a growing knowledge base learned throughout the discourse, and a suitable con- straint solver does the job of incorporating new pieces o...... of abductive reasoning. The approach fits with possible worlds semantics that allows both standard first-order and non-monotonic semantics....

  18. Path following control of planar snake robots using virtual holonomic constraints: theory and experiments.

    Science.gov (United States)

    Rezapour, Ehsan; Pettersen, Kristin Y; Liljebäck, Pål; Gravdahl, Jan T; Kelasidi, Eleni

    This paper considers path following control of planar snake robots using virtual holonomic constraints. In order to present a model-based path following control design for the snake robot, we first derive the Euler-Lagrange equations of motion of the system. Subsequently, we define geometric relations among the generalized coordinates of the system, using the method of virtual holonomic constraints. These appropriately defined constraints shape the geometry of a constraint manifold for the system, which is a submanifold of the configuration space of the robot. Furthermore, we show that the constraint manifold can be made invariant by a suitable choice of feedback. In particular, we analytically design a smooth feedback control law to exponentially stabilize the constraint manifold. We show that enforcing the appropriately defined virtual holonomic constraints for the configuration variables implies that the robot converges to and follows a desired geometric path. Numerical simulations and experimental results are presented to validate the theoretical approach.

  19. Constraints on muon-specific dark forces

    CERN Document Server

    Karshenboim, Savely G; Pospelov, Maxim

    2014-01-01

    The recent measurement of the Lamb shift in muonic hydrogen allows for the most precise extraction of the charge radius of the proton which is currently in conflict with other determinations based on $e-p$ scattering and hydrogen spectroscopy. This discrepancy could be the result of some new muon-specific force with O(1-100) MeV force carrier---in this paper we concentrate on vector mediators. Such an explanation faces challenges from the constraints imposed by the $g-2$ of the muon and electron as well as precision spectroscopy of muonic atoms. In this work we complement the family of constraints by calculating the contribution of hypothetical forces to the muonium hyperfine structure. We also compute the two-loop contribution to the electron parity violating amplitude due to a muon loop, which is sensitive to the muon axial-vector coupling. Overall, we find that the combination of low-energy constraints favors the mass of the mediator to be below 10 MeV, and that a certain degree of tuning is required betwe...

  20. Hubble parameter measurement constraints on dark energy

    CERN Document Server

    Farooq, Omer; Ratra, Bharat

    2012-01-01

    We use 21 Hubble parameter versus redshift data points, from Gazta\\~{n}aga et al. (2009), Stern et al. (2010), and Moresco et al. (2012), to place constraints on model parameters of constant and time-evolving dark energy cosmologies. This is the largest set of H(z) data considered to date. The inclusion of the 8 new Moresco et al. (2012) measurements results in H(z) constraints more restrictive than those derived by Chen & Ratra (2011b). These constraints are now almost as restrictive as those that follow from current Type Ia supernova (SNIa) apparent magnitude versus redshift data (Suzuki et al. 2012), which now more carefully account for systematic uncertainties. This is a remarkable result. We emphasize however that SNIa data have been studied for a longer time than the H(z) data, possibly resulting in a better estimate of potential systematic errors in the SNIa case. A joint analysis of the H(z), baryon acoustic oscillation peak length scale, and SNIa data favors a spatially-flat cosmological model cu...

  1. Metabolic constraint-based refinement of transcriptional regulatory networks.

    Science.gov (United States)

    Chandrasekaran, Sriram; Price, Nathan D

    2013-01-01

    There is a strong need for computational frameworks that integrate different biological processes and data-types to unravel cellular regulation. Current efforts to reconstruct transcriptional regulatory networks (TRNs) focus primarily on proximal data such as gene co-expression and transcription factor (TF) binding. While such approaches enable rapid reconstruction of TRNs, the overwhelming combinatorics of possible networks limits identification of mechanistic regulatory interactions. Utilizing growth phenotypes and systems-level constraints to inform regulatory network reconstruction is an unmet challenge. We present our approach Gene Expression and Metabolism Integrated for Network Inference (GEMINI) that links a compendium of candidate regulatory interactions with the metabolic network to predict their systems-level effect on growth phenotypes. We then compare predictions with experimental phenotype data to select phenotype-consistent regulatory interactions. GEMINI makes use of the observation that only a small fraction of regulatory network states are compatible with a viable metabolic network, and outputs a regulatory network that is simultaneously consistent with the input genome-scale metabolic network model, gene expression data, and TF knockout phenotypes. GEMINI preferentially recalls gold-standard interactions (p-value = 10(-172)), significantly better than using gene expression alone. We applied GEMINI to create an integrated metabolic-regulatory network model for Saccharomyces cerevisiae involving 25,000 regulatory interactions controlling 1597 metabolic reactions. The model quantitatively predicts TF knockout phenotypes in new conditions (p-value = 10(-14)) and revealed potential condition-specific regulatory mechanisms. Our results suggest that a metabolic constraint-based approach can be successfully used to help reconstruct TRNs from high-throughput data, and highlights the potential of using a biochemically-detailed mechanistic framework to

  2. Experimental behaviour of a argon plasma, which is passed by a high current intensity, with different magnetic field configurations; Comportamiento experimental de un plasma de argon en diferentes configuraciones de campo magnetico y a elevadas corrientes

    Energy Technology Data Exchange (ETDEWEB)

    Lozano, J.

    1964-07-01

    In a lineal discharge, the longitudinal and azimuthal magnetic fields produced by the current through the tube and the returning conductors, which have 4 different forms, are determined with a magnetic probe, which has a radial and longitudinal displacement. The plasma is produced discharging a 135{mu}F and 9 KV capacitor bank through Argon at 10{sup -}1 Torr. (Author) 5 refs.

  3. Investigations on contribution of glial inwardly-rectifying K+ current to membrane potential and ion flux: An experimental and theoretical study

    Directory of Open Access Journals (Sweden)

    Sheng-Nan Wu

    2015-01-01

    Full Text Available The inwardly rectifying K+ current [IK(IR] allows large inward K+ currents at potentials negative to K+ equilibrium potential (EK and it becomes small outward K+ currents at those positive to EK. How changes of such currents enriched in glial cells can influence the functions of glial cell, neurons, or both is not clearly defined, although mutations of Kir4.1 channels have been demonstrated to cause serious neurological disorders. In this study, we identified the presence of IK(IR in human glioma cells (U373 and U87 cells. The amplitude of IK(IR in U373 cells was subject to inhibition by amitriptyline, arecoline, or BaCl2. The activity of inwardly rectifying K+ channels was also clearly detected, and single-channel conductance of these channels was calculated to be around 23 pS. Moreover, based on a simulation model derived from neuron–glial interaction mediated by ion flux, we further found out that incorporation of glial IK(IR conductance into the model can significantly contribute to regulation of extracellular K+ concentrations and glial resting potential, particularly during high-frequency stimulation. Glial cells and neurons can mutually modulate their expression of ion channels through K+ ions released into the extracellular space. It is thus anticipated that glial IK(IR may be a potential target utilized to influence the activity of neuronal and glial cells as well as their interaction.

  4. Experimental Section: On the magnetic field distribution generated by a dipolar current source situated in a realistically shaped compartment model of the head

    NARCIS (Netherlands)

    Meijs, J.W.H.; Bosch, F.G.C.; Peters, M.J.; Lopes da silva, F.H.

    1987-01-01

    The magnetic field distribution around the head is simulated using a realistically shaped compartment model of the head. The model is based on magnetic resonance images. The 3 compartments describe the brain, the skull and the scalp. The source is represented by a current dipole situated in the

  5. Cosmological constraints on the neutron lifetime

    CERN Document Server

    Salvati, Laura; Consiglio, Rossella; Melchiorri, Alessandro

    2015-01-01

    We derive new constraints on the neutron lifetime based on the recent Planck 2015 observations of temperature and polarization anisotropies of the CMB. Under the assumption of standard Big Bang Nucleosynthesis, we show that Planck data constrains the neutron lifetime to $\\tau_n=(907 \\pm 69) \\, [\\text{s}]$ at $68 \\%$ c.l.. Moreover, by including the direct measurements of primordial Helium abundance of Izotov et al. 2014 and Mucciarelli et al. 2014, we show that cosmological data provide the stringent constraint $\\tau_n=(905.7 \\pm 7.8) \\, [\\text{s}]$. This value is in tension with the most recent experimental value of $\\tau_n^{\\text{bottle}}=(879.6 \\pm 0.8) \\, [\\text{s}]$ provided by the "bottle method" based on Ultra Cold Neutrons, but in agreement with the experimental value of $\\tau_n^{\\text{beam}}=(888.0 \\pm 2.1) \\, [\\text{s}]$ based on the "beam method". Future CMB surveys as COrE+, in combination with a weak lensing survey as EUCLID, could constrain the neutron life time up to a $\\sim 6$ s precision.

  6. A critical reevaluation of radio constraints on annihilating dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Cholis, Ilias; Hooper, Dan; Linden, Tim

    2015-04-01

    A number of groups have employed radio observations of the Galactic center to derive stringent constraints on the annihilation cross section of weakly interacting dark matter. In this paper, we show that electron energy losses in this region are likely to be dominated by inverse Compton scattering on the interstellar radiation field, rather than by synchrotron, considerably relaxing the constraints on the dark matter annihilation cross section compared to previous works. Strong convective winds, which are well motivated by recent observations, may also significantly weaken synchrotron constraints. After taking these factors into account, we find that radio constraints on annihilating dark matter are orders of magnitude less stringent than previously reported, and are generally weaker than those derived from current gamma-ray observations.

  7. Overlapping constraint for variational surface reconstruction

    DEFF Research Database (Denmark)

    Aanæs, Henrik; Solem, J.E.

    2005-01-01

    In this paper a counter example, illustrating a shortcoming in most variational formulations for 3D surface estimation, is presented. The nature of this shortcoming is a lack of an overlapping constraint. A remedy for this shortcoming is presented in the form of a penalty function with an analysis...... of the effects of this function on surface motion. For practical purposes, this will only have minor influence on current methods. However, the insight provided in the analysis is likely to influence future developments in the field of variational surface reconstruction....

  8. Economic Growth in Croatia: Potential and Constraints

    Directory of Open Access Journals (Sweden)

    Athanasios Vamvakidis

    2008-03-01

    Full Text Available This paper examines the factors and constraints that affect recent and potential growth in Croatia, as well as policies that can influence it. On current productivity trends, it estimates Croatia’s potential growth rate at 4–4½ percent, a result reasonably robust to different methodologies. For growth to be sustained at a significantly higher rate, the business environment needs to be improved through further measures to reduce the administrative burden, legal uncertainties, and corruption. The analysis also emphasizes the importance of attracting more greenfield foreign direct investment, and reforms to reduce the role of the state in the economy through fiscal consolidation and faster privatization.

  9. Gamma ray constraints on decaying dark matter

    DEFF Research Database (Denmark)

    Cirelli, M.; Moulin, E.; Panci, P.

    2012-01-01

    We derive new bounds on decaying dark matter from the gamma ray measurements of (i) the isotropic residual (extragalactic) background by Fermi and (ii) the Fornax galaxy cluster by H.E.S.S. We find that those from (i) are among the most stringent constraints currently available, for a large range...... of dark matter masses and a variety of decay modes, excluding half-lives up to similar to 10(26) to few 10(27) seconds. In particular, they rule out the interpretation in terms of decaying dark matter of the e(+/-) spectral features in PAMELA, Fermi and H.E.S.S., unless very conservative choices...

  10. Gamma ray constraints on decaying dark matter

    DEFF Research Database (Denmark)

    Cirelli, M.; Moulin, E.; Panci, P.

    2012-01-01

    We derive new bounds on decaying dark matter from the gamma ray measurements of (i) the isotropic residual (extragalactic) background by Fermi and (ii) the Fornax galaxy cluster by H.E.S.S. We find that those from (i) are among the most stringent constraints currently available, for a large range...... of dark matter masses and a variety of decay modes, excluding half-lives up to similar to 10(26) to few 10(27) seconds. In particular, they rule out the interpretation in terms of decaying dark matter of the e(+/-) spectral features in PAMELA, Fermi and H.E.S.S., unless very conservative choices...

  11. Constraints on torsion from bounds on lorentz violation.

    Science.gov (United States)

    Kostelecký, V Alan; Russell, Neil; Tasson, Jay D

    2008-03-21

    Exceptional sensitivity to space-time torsion can be achieved by searching for its couplings to fermions. Recent experimental searches for Lorentz violation are exploited to extract new constraints involving 19 of the 24 independent torsion components down to levels of order 10(-31) GeV.

  12. Constraints on nonmetricity from bounds on Lorentz violation

    Science.gov (United States)

    Foster, Joshua; Kostelecký, V. Alan; Xu, Rui

    2017-04-01

    Spacetime nonmetricity can be studied experimentally through its couplings to fermions and photons. We use recent high-precision searches for Lorentz violation to deduce first constraints involving the 40 independent nonmetricity components down to levels of order 10-43 GeV .

  13. Experimental constraints on the origin of potassium-rich adakites in eastern China%中国东部富钾埃达克岩成因的实验约束

    Institute of Scientific and Technical Information of China (English)

    RobertP.PAPP; 肖龙; 等

    2002-01-01

    Adakites are geochemically distinct volcanic and plutonic granitoid rocks found in intraoceanic island arc settings where relatively young, hot oceanic lithosphere has been subducted and melted (termed "slab melting"), and in continental arcs, such as the Andes, where melting has taken place at the base of tectonically- or magmatically-thickened lower crust (termed "lower crustal melting"). In both settings, the distinctive geochemical signature of adakitic granitoids is attributed to an origin by partial melting of a variably-hydrated metabasaltic protolith at sufficient depths for garnet to be stable within the residual crystalline assemblage (I.e., residues of garnet-amphibolite and/or eclogite). Once generated, "pristine" or "parental" adakite melts may have their composition subsequently modified by processes of assimilation (of either mantle or continental material) and crystal fractionation during transport to and emplacement in the middle-upper crust. Late Mesozoic (early-mid Cretaceous, ~160-110 Ma) adakites in eastern China are unusually rich in potassium (K2O) and other large-ion lithophile elements (e.g., Ba, Th, U), with low Na2O/ K2O ratios (~1.0-1.1), in contrast to sodic adakites, found in eastern China and elsewhere, which resemble experimental adakite liquids produced by dehydration melting of basalt in the garnet-amphibolite to eclogite facies. And which formed by either slab melting of oceanic crust, or by partial melting of broadly basaltic, lower crustal protoliths. Despite these compositional differences, their overall geochemical character defines the potassic granitoids of eastern China as adakites. We attribute the unique chemistry of these potassium-rich adakites to either peculiarities in the composition of their source, or to the processes, including assimiliation and fractional crystallization (AFC), that subsequently modified parental adakite magmas. Although the apparent lack of proximity to a subduction zone suggests that

  14. The constraints on new physics from b → s transitions

    Science.gov (United States)

    Ge, Zhao-Feng; Feng, Tai-Fu; Zhang, Hai-Bin

    2016-08-01

    Assuming that the corrections to relevant Wilson coefficients from new physics (NP) contain the possible CP phases, we analyze the constraints on the NP corrections from the updated experimental data on rare B decays from LHCb, BABAR, and BELLE, etc. systematically. Through global fit among the theoretical evaluations and corresponding experimental observations, we find that the possible CP phases of the corrections to relevant Wilson coefficients from NP affect the allowed parameter space obviously.

  15. EXPERIMENTAL RESEARCHES OF ELECTRO-THERMAL RESISTIBILITY OF SEND-OFFS AND CABLES TO ACTION RATIONED ON THE INTERNATIONAL STANDARD OF IEC 62305-1-2010 OF APERIODIC IMPULSE OF CURRENT OF ARTIFICIAL LIGHTNING

    Directory of Open Access Journals (Sweden)

    M.I. Baranov

    2016-03-01

    Full Text Available Purpose. Experimental researches of electro-thermal resistibility of cable-explorer products, applied in the power electric circuits of objects of electric-power industry, to action on its copper and aluminum parts bearings a current rationed on the International Standard of IEC 62305-1-2010 aperiodic impulse 10/350 μs of current of artificial lightning. Methodology. Electrophysics bases of technique of high tensions and high pulsed currents (HPC, and also scientific and technical bases of planning of devices of high-voltage impulsive technique and measuring HPC in them. Results. Experimental a way the quantitative levels of maximal values maximum of possible and critical closenesses of aperiodic impulse 10/350 μs of current of artificial lightning with rationed on the international standard of IEC 62305-1-2010 peak-temporal parameters and admittances on them in copper (aluminum parts bearings a current of send-offs and cables with a polyethylene (PET and polyvinylchloride (PVCH isolation. Originality. First in world practice on the unique powerful high-voltage generator of HPC of artificial lightning experimental researches of resistibility to lightning of pre-production models of send-offs (cables are conducted with copper (aluminum tendons, PET and PVCH by an isolation, in-use in power electric circuits of electric-power industry objects. Practical value. The use in practice of protecting from lightning of the got results will allow substantially to promote functional and fire-prevention safety of engineering communications of objects of industrial electroenergy in the conditions of action on them of short shots of linear lightning.

  16. Illumination angle and layer thickness influence on the photo current generation in organic solar cells: A combined simulative and experimental study

    Directory of Open Access Journals (Sweden)

    Jan Mescher

    2015-07-01

    Full Text Available In most future organic photovoltaic applications, such as fixed roof installations, facade or clothing integration, the solar cells will face the sun under varying angles. By a combined simulative and experimental study, we investigate the mutual interdependencies of the angle of light incidence, the absorber layer thickness and the photon harvesting efficiency within a typical organic photovoltaic device. For thin absorber layers, we find a steady decrease of the effective photocurrent towards increasing angles. For 90-140 nm thick absorber layers, however, we observe an effective photocurrent enhancement, exhibiting a maximum yield at angles of incidence of about 50°. Both effects mainly originate from the angle-dependent spatial broadening of the optical interference pattern inside the solar cell and a shift of the absorption maximum away from the metal electrode.

  17. Experimental Investigation on the Influence of Axial Magnetic Field Distribution on Resisting the Constriction of a High-Current Vacuum Arc

    Institute of Scientific and Technical Information of China (English)

    SHI Zongqian; LIU Zhigang; JIA Shenli; SONG Xiaochuan; WANG Lijun

    2009-01-01

    Effect of the axial magnetic field (AMF) on resisting the constriction of a high-current vacuum arc is studied in this paper. Two typical AMF distributions were investigated, i.e., the traditional bell-shaped AMF, and the saddle-shaped AMF. Experiments were conducted in a detachable vacuum chamber with a rms arc current in the range of 10 kA to 25 kA. The arc column was photographed by a high-speed digital camera with an exposure time of 2 microseconds. The constriction of the vacuum arc was compared by processing the images of the arc column under the two different field configurations and numerically determining the dimensions of the arc column near the electrodes. It was also confirmed that the AMF distribution had a signifcant influence on its effectiveness in resisting arc constriction, Furthermore, the AMF strength near the periphery of the arc is more influential than that at the centre of the electrodes in resisting arc constriction.

  18. Two complementary approaches to right-handed currents

    Energy Technology Data Exchange (ETDEWEB)

    Gemmler, Katrin M.

    2012-04-17

    Flavour observables impose strong constraints on models of new physics. We study whether right-handed currents can provide a realistic extension to the Standard Model. We analyse two complementary models. These setups lead to new flavour violating interactions in the right-handed sector. We first consider a bottom-up approach assuming a left-right symmetric flavour group broken only by the Yukawa couplings. In this model the vertical stroke V{sub ub} vertical stroke problem can be solved. Secondly we study the Left-Right Model. We perform a comprehensive numerical analysis, including all known experimental constraints from {Delta}F=2 observables and the decay B {yields}X{sub s}{gamma} simultaneously. We observe that there exist regions in parameter space in accordance with the all data. In this model all flavour anomalies can be resolved except the vertical stroke V{sub ub} vertical stroke problem.

  19. CALCULATION AND EXPERIMENTAL ESTIMATION OF RESULTS OF ELECTRO-THERMAL ACTION OF RATIONED BY THE INTERNATIONAL STANDARD IEC 62305-1-2010 IMPULSE CURRENT OF SHORT BLOW OF ARTIFICIAL LIGHTNING ON THE THIN-WALLED COVERAGE FROM STAINLESS STEEL

    Directory of Open Access Journals (Sweden)

    M. I. Baranov

    2017-03-01

    Full Text Available Purpose. Calculation and experimental researches of electro-thermal resistibility of the pre-production thin-walled sheet models of outward roof of height technical buildings from stainless steel are easily soiled 12Х18Н10Т to direct action on them rationed by the International Standard IEC 62305-1-2010 aperiodic impulse of current of short bow of artificial lightning of temporal form 10/350 μs with the proper admittances on his peak-temporal parameters (PTP. Methodology. Electrophysics bases of technique of high voltage and large impulsive currents (LIC, and also scientific and technical bases of planning of high-voltage impulsive devices and measuring methods in them LIC with followings below extreme PTP: amplitude of impulse of current of ImL=200 кА (with admittance ±10 %; integral of action of impulse of current of JL=10·106 A2·s (with admittance ±35 %; %; duration of wavefront current of T1=10 μs (with admittance ±20 %; time, proper amplitude of impulse of current of ImL, tmL≤24 μs (with admittance ±20 %; duration of flowing of impulse of current of T2=350 μs (with admittance ±10 %. Results. The results of evaluation calculation and experimental researches of electro-thermal resistibility of the indicated pre-production sheet models are resulted measuring in the plan of 0,5 x 0,5 m from stainless steel are easily soiled the 12Х18Н10Т thickness of 1 mm to action on them of aperiodic impulse of current of short blow of artificial lightning with rationed PTP on the requirements of the International Standard IEC 62305-1-2010. In high current experiments amplitude of ImL of the aperiodic rationed impulse of current of artificial lightning of temporal form of T1/T2=15 μs/315 μs changed in the range of (100-184 кА. The integral of action of JL of impulse of current for I-IV of levels of protection of lightning of technical objects (TO numeral made from 2,32·106 А2·s to 7,88·106 А2·s, and the flowing through the

  20. Constraint programming and decision making

    CERN Document Server

    Kreinovich, Vladik

    2014-01-01

    In many application areas, it is necessary to make effective decisions under constraints. Several area-specific techniques are known for such decision problems; however, because these techniques are area-specific, it is not easy to apply each technique to other applications areas. Cross-fertilization between different application areas is one of the main objectives of the annual International Workshops on Constraint Programming and Decision Making. Those workshops, held in the US (El Paso, Texas), in Europe (Lyon, France), and in Asia (Novosibirsk, Russia), from 2008 to 2012, have attracted researchers and practitioners from all over the world. This volume presents extended versions of selected papers from those workshops. These papers deal with all stages of decision making under constraints: (1) formulating the problem of multi-criteria decision making in precise terms, (2) determining when the corresponding decision problem is algorithmically solvable; (3) finding the corresponding algorithms, and making...

  1. Effect of variable winds on current structure and Reynolds stresses in a tidal flow: analysis of experimental data in the eastern English Channel

    Directory of Open Access Journals (Sweden)

    K. A. Korotenko

    2012-11-01

    Full Text Available Wind and wave effects on tidal current structure and turbulence throughout the water column are examined using an upward-looking acoustic Doppler current profiler (ADCP. The instrument has been deployed on the seafloor of 18-m mean depth, off the north-eastern French coast in the eastern English Channel, over 12 tidal cycles, and covered the period of the transition from mean spring to neap tide, and forcing regimes varied from calm to moderate storm conditions. During storms, we observed gusty winds with magnitudes reaching 15 m s−1 and wave heights reaching up to 1.3 m. Analysis of velocity spectra revealed a noticeable contribution of wind-induced waves to spectral structure of velocity fluctuations within the subsurface layer. Near the surface, stormy winds and waves produced a significant intensification of velocity fluctuations, particularly when the sustained wind blew against the ebb tide flow. As during wavy periods, the variance-derived Reynolds stress estimates might include a wave-induced contamination, we applied the Variance Fit method to obtain unbiased stresses and other turbulent quantities. Over calm periods, the turbulent quantities usually decreased with height above the seabed. The stresses were found to vary regularly with the predominantly semidiurnal tidal flow. The along-shore stress being generally greater during the flood flow (~2.7 Pa than during the ebb flow (~−0.6 Pa. The turbulent kinetic energy production rate, P, and eddy viscosity, Az, followed a nearly regular cycle with close to a quarter-diurnal period. As for the stresses, near the seabed, we found the maximum values of estimated quantities of P and Az to be 0.1 Wm−3 and 0.5 m2 s−1, respectively, during the flood flow. Over the storm periods, we found the highest unbiased stress values (~−2.6 Pa during ebb when tidal currents were opposite to the

  2. Effect of variable winds on current structure and Reynolds stresses in a tidal flow: analysis of experimental data in the Eastern English Channel

    Directory of Open Access Journals (Sweden)

    K. A. Korotenko

    2012-06-01

    Full Text Available Wind and wave effects on tidal current structure and turbulence throughout the water column are examined using an upward-looking acoustic Doppler current profiler (ADCP. The instrument has been deployed on the seafloor of 20-m depth, off the North-Eastern French coast in the Eastern English Channel over 12 tidal cycles and covered the period of the transition from mean spring to neap tide and forcing regimes varied from calm to moderate storm conditions. During storms, we observed gusty winds with magnitude reached 15 m s−1 and wave height reached up to 1.3 m. Analysis of velocity spectra revealed a noticeable contribution of wind-induced waves to spectral structure of velocity fluctuations within the upper 10-m layer. Near the surface, stormy winds and waves produced a significant intensification of velocity fluctuations, particularly when the sustained wind blew against the ebb tide flow. As during wavy periods the variance-derived Reynolds stress estimates might include a wave-induced contamination, we applied the Variance Fit method to obtain unbiased stresses and other turbulent quantities. Over calm periods, the turbulent quantities usually decreased with height above the seabed. The stresses were found to vary regularly with the predominantly semidiurnal tidal flow, with the along-shore stress being generally greater during the flood flow (~2.7 Pa than during the ebb flow (~−0.6 Pa. The turbulent kinetic energy production rate, P, and eddy viscosity, Az}, followed a nearly regular cycle with close to a quarter-diurnal period. As for the stresses, near the seabed, we found the maximum values of estimated quantities of P and Az to be 0.1 W m−3 and 0.5 m2 s−1, respectively, during the flood flow. Over the storm periods, we found the highest stress values (~−2 Pa during ebb when tidal currents were opposite to the southwesterly winds while

  3. Experimental constraints on the $\\omega$-nucleus real potential

    CERN Document Server

    Friedrich, S; Metag, V; Bayadilov, D; Bantes, B; Beck, R; Beloglazov, Y A; Böse, S; Brinkmann, K -T; Challand, Th; Crede, V; Dahlke, T; Dietz, F; Drexler, P; Eberhardt, H; Elsner, D; Ewald, R; Fornet-Ponse, K; Frommberger, F; Funke, Ch; Gottschall, M; Gridnev, A; Grüner, M; Gutz, E; Hammann, Ch; Hammann, D; Hannappel, J; Hartmann, J; Hillert, W; Hirenzaki, S; Hoffmeister, P; Honisch, Ch; Jaegle, I; Kaiser, D; Kalinowsky, H; Kammer, S; Keshelashvili, I; Kleber, V; Klein, F; Krusche, B; Lang, M; Lopatin, I V; Maghrbi, Y; Nanova, M; Nagahiro, H; Müller, J; Odenthal, T; Piontek, D; Rostomyan, T; Schaepe, S; Schmidt, Ch; Schmieden, H; Schmitz, R; Seifen, T; Thiel, A; Thoma, U; van Pee, H; Walther, D; Weil, J; Wendel, Ch; Wiedner, U; Wilson, A; Winnebeck, A; Zenke, F

    2014-01-01

    In a search for $\\omega$ mesic states, the production of $\\omega$-mesons in coincidence with forward going protons has been studied in photon induced reactions on $^{12}$C for incident photon energies of 1250 - 3100 MeV. The $\\pi^0 \\gamma$ pairs from decays of bound or quasi-free $\\omega$-mesons have been measured with the CBELSA/TAPS detector system in coincidence with protons registered in the MiniTAPS forward array. Structures in the total energy distribution of the $\\pi^0 \\gamma$ pairs, which would indicate the population and decay of bound $\\omega~^{11}$B states, are not observed. The $\\pi^0 \\gamma$ cross section of 0.3 nb/MeV/sr observed in the bound state energy regime between -100 and 0 MeV may be accounted for by yield leaking into the bound state regime because of the large in-medium width of the $\\omega$-meson. A comparison of the measured total energy distribution with calculations suggests the real part $V_0$ of the $\\omega~^{11}$B potential to be small and only weakly attractive with $V_0(\\rho=\\...

  4. Experimental constraints on the ω–nucleus real potential

    Energy Technology Data Exchange (ETDEWEB)

    Friedrich, S., E-mail: stefan.friedrich@exp2.physik.uni-giessen.de [II. Physikalisches Institut, Universität Gießen (Germany); Makonyi, K. [II. Physikalisches Institut, Universität Gießen (Germany); Metag, V. [II. Physikalisches Institut, Universität Gießen (Germany); Department of Physics, Florida State University, Tallahassee, FL (United States); Bayadilov, D. [Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Bantes, B. [Departement Physik, Universität Basel (Switzerland); Beck, R. [Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn (Germany); Beloglazov, Y.A. [Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Böse, S. [Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn (Germany); Brinkmann, K.-T. [II. Physikalisches Institut, Universität Gießen (Germany); Challand, Th. [Departement Physik, Universität Basel (Switzerland); Crede, V. [Department of Physics, Florida State University, Tallahassee, FL (United States); Dahlke, T. [Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn (Germany); and others

    2014-09-07

    In a search for ω mesic states, the production of ω-mesons in coincidence with forward going protons has been studied in photon induced reactions on {sup 12}C for incident photon energies of 1250–3100 MeV. The π{sup 0}γ pairs from decays of bound or quasi-free ω-mesons have been measured with the CBELSA/TAPS detector system in coincidence with protons registered in the MiniTAPS forward array. Structures in the total energy distribution of the π{sup 0}γ pairs, which would indicate the population and decay of bound ω{sup 11}B states, are not observed. The π{sup 0}γ cross section of 0.3 nb MeV{sup −1} sr{sup −1} observed in the bound state energy regime between −100 and 0 MeV may be accounted for by yield leaking into the bound state regime because of the large in-medium width of the ω-meson. A comparison of the measured total energy distribution with calculations suggests the real part V{sub 0} of the ω{sup 11}B potential to be small and only weakly attractive with V{sub 0}(ρ=ρ{sub 0})=−15±35(stat)±20(syst) MeV in contrast to some theoretical predictions of attractive potentials with a depth of 100–150 MeV.

  5. Experimental constraints on the ω–nucleus real potential

    Directory of Open Access Journals (Sweden)

    S. Friedrich

    2014-09-01

    Full Text Available In a search for ω mesic states, the production of ω-mesons in coincidence with forward going protons has been studied in photon induced reactions on 12C for incident photon energies of 1250–3100 MeV. The π0γ pairs from decays of bound or quasi-free ω-mesons have been measured with the CBELSA/TAPS detector system in coincidence with protons registered in the MiniTAPS forward array. Structures in the total energy distribution of the π0γ pairs, which would indicate the population and decay of bound ω 11B states, are not observed. The π0γ cross section of 0.3 nb MeV−1 sr−1 observed in the bound state energy regime between −100 and 0 MeV may be accounted for by yield leaking into the bound state regime because of the large in-medium width of the ω-meson. A comparison of the measured total energy distribution with calculations suggests the real part V0 of the ω 11B potential to be small and only weakly attractive with V0(ρ=ρ0=−15±35(stat±20(syst MeV in contrast to some theoretical predictions of attractive potentials with a depth of 100–150 MeV.

  6. Experimental constraints on gold and silver solubility in iron sulfides

    Energy Technology Data Exchange (ETDEWEB)

    Pal' yanova, Galina [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3, Koptyuga, Novosibirsk, 630090 (Russian Federation); Novosibirsk State University, Russia, 2, Pirogova, Novosibirsk, 630090 (Russian Federation); Mikhlin, Yuri [Institute of Chemistry and Chemical Technology, Siberian Branch of the Russian Academy of Sciences, Akademgorodok, 50/24, Krasnoyarsk, 660036 (Russian Federation); Kokh, Konstantin, E-mail: k.a.kokh@gmail.com [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3, Koptyuga, Novosibirsk, 630090 (Russian Federation); Novosibirsk State University, Russia, 2, Pirogova, Novosibirsk, 630090 (Russian Federation); Siberian Physical–Technical Institute of Tomsk State University, 1, Novosobornaya, Tomsk, 634050 (Russian Federation); Karmanov, Nick [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3, Koptyuga, Novosibirsk, 630090 (Russian Federation); Seryotkin, Yurii [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3, Koptyuga, Novosibirsk, 630090 (Russian Federation); Novosibirsk State University, Russia, 2, Pirogova, Novosibirsk, 630090 (Russian Federation)

    2015-11-15

    Experiments were performed to determine crystallization of Fe,S-melts (pyriti≿ and troilitic with molar ratio S/Fe ratios of 2 and 1, respectively) containing traces of gold and silver at (Ag/Au){sub wt} ratios varying from 10 to 0.1. The solid products were studied by optical microscopy, scanning electron microscopy, X-ray powder diffraction (XRD), microprobe analysis, and X-ray photoelectron spectroscopy (XPS) in order to reveal the concentration limits of “invisible” gold and silver in magmatic iron sulfides, and to determine the influence of sulfur on forms of precious metals in the Fe–S system with different Ag/Au ratios. Au–Ag phases do not form inclusions but instead concentrate on the grain boundaries in the synthetic pyrrhotite and troilite, while pyrite comprises micro- (1–5 μm) and macroinclusions of Au–Ag alloys and Au–Ag sulfides. In “pyriti≿” systems, the fineness of alloys increases from 650 to 970‰ and the composition of sulfides changes from acanthite (Ag{sub 2}S) to uytenbogaardtite (Ag{sub 3}AuS{sub 2}) and petrovskaite (AgAuS) as the Ag/Au ratio decreases. The concentrations of “invisible” precious metals revealed in troilite were 0.040 ± 0.013 wt.% Au and 0.079 ± 0.016 wt.% Ag. Measured concentrations in pyrite and pyrrhotite were <0.024 wt.% Au and <0.030 wt.% Ag. The surface layers of iron sulfides probed with XPS were enriched in the precious metals, and in silver relative to gold, especially in the systems with Fe/S = 1, probably, due to depletion of the metallic alloy surfaces with gold. Au- and Ag-bearing iron sulfides crystallized primarily from melts may be the source of redeposited phases in hydrothermal and hypergene processes. - Highlights: • The samples of Fe–S–Au–Ag system were synthesized. • Coupled solubility of gold and silver in iron sulfides was specified. • Ag–Au inclusions on surfaces of iron sulfides are likely to be enriched in silver. • Au–Ag sulfides can exist along with native gold in pyrite.

  7. New Experimental Constraints for the Standard Model from Muon Decay

    CERN Document Server

    Bayes, R; Hillairet, A; Davydov, Yu I; Depommier, P; Faszer, W; Gagliardi, C A; Gaponenko, A; Gill, D R; Grossheim, A; Gumplinger, P; Hasinoff, M D; Henderson, R S; Hu, J; Koetke, D D; MacDonald, R P; Marshall, G; Mathie, E L; Mischke, R E; Olchanski, K; Olin, A; Openshaw, R; Poutissou, J -M; Poutissou, R; Selivanov, V; Sheffer, G; Shin, B; Stanislaus, T D S; Tacik, R; Tribble, R E

    2010-01-01

    The TWIST Collaboration has completed a new measurement of the energy-angle spectrum of positrons from the decay of highly polarized muons. A simultaneous measurement of the muon decay parameters {\\rho}, {\\delta}, and (P_{\\mu}){\\xi} tests the Standard Model (SM) in a purely leptonic process and provides improved limits for relevant extensions to the SM. Specifically, these results set significant new limits on the heavy $W$ mass and the mixing angle in a class of left-right symmetric models.

  8. Reentry trajectory optimization for hypersonic vehicle satisfying complex constraints

    Institute of Scientific and Technical Information of China (English)

    Jiang Zhao; Rui Zhou

    2013-01-01

    The reentry trajectory optimization for hypersonic vehicle (HV) is a current problem of great interest. Some complex constraints, such as waypoints for reconnaissance and no-fly zones for threat avoidance, are inevitably involved in a global strike mission. Of the many direct methods, Gauss pseudospectral method (GPM) has been demonstrated as an effective tool to solve the tra-jectory optimization problem with typical constraints. However, a series of difficulties arises for complex constraints, such as the uncertainty of passage time for waypoints and the inaccuracy of approximate trajectory near no-fly zones. The research herein proposes a multi-phase technique based on the GPM to generate an optimal reentry trajectory for HV satisfying waypoint and no-fly zone constraints. Three kinds of specific breaks are introduced to divide the full trajectory into multiple phases. The continuity conditions are presented to ensure a smooth connection between each pair of phases. Numerical examples for reentry trajectory optimization in free-space flight and with complex constraints are used to demonstrate the proposed technique. Simulation results show the feasible application of multi-phase technique in reentry trajectory optimization with way-point and no-fly zone constraints.

  9. Physical properties and cytotoxicity comparison of experimental gypsum-based biomaterials with two current dental cement materials on L929 fibroblast cells

    Directory of Open Access Journals (Sweden)

    Nafsiyah Mahshim

    2013-01-01

    Full Text Available Aim: To evaluate physical properties and cytotoxicity of pure gypsum-based (pure-GYP and experimental gypsum-based biomaterials mixed with polyacrylic acid (Gyp-PA. The results were compared with calcium hydroxide (CH and glass ionomer cement (GIC for application as base/liner materials. Materials and Methods: Vicat′s needle was used to measure the setting time and solubility (% was determined by percentage of weight loss of the materials following immersion in distilled water. For cytotoxicity test, eluates of different concentrations of materials were obtained and pipetted onto L-929 mouse fibroblast cultures and incubated for 3 days. Cellular viability was assessed using Dimethylthiazol diphenyltetrazolium bromide test to determine the cytotoxicity level. Statistical significance was determined by one-way analysis of variance followed by post hoc test ( P Gyp-PA > CH = GIC. The pure-Gyp was found as the least cytotoxic materials at different concentrations. At 100 mg/mL dilutions of materials in growth medium highest cytotoxicity was observed with CH group. Conclusion: Cytotoxic effect was not observed with pure-Gyp; application of this novel biomaterial on deeper dentin/an exposed pulp and possibility of gradual replacement of this biodegradable material by dentin like structure would be highly promising.

  10. Optimization of mask manufacturing rule check constraint for model based assist feature generation

    Science.gov (United States)

    Shim, Seongbo; Kim, Young-chang; Chun, Yong-jin; Lee, Seong-Woo; Lee, Suk-joo; Choi, Seong-woon; Han, Woo-sung; Chang, Seong-hoon; Yoon, Seok-chan; Kim, Hee-bom; Ki, Won-tai; Woo, Sang-gyun; Cho, Han-gu

    2008-11-01

    SRAF (sub-resolution assist feature) generation technology has been a popular resolution enhancement technique in photo-lithography past sub-65nm node. It helps to increase the process window, and these are some times called ILT(inverse lithography technology). Also, many studies have been presented on how to determine the best positions of SRAFs, and optimize its size. According to these reports, the generation of SRAF can be formulated as a constrained optimization problem. The constraints are the side lobe suppression and allowable minimum feature size or MRC (mask manufacturing rule check). As we know, bigger SRAF gives better contribution to main feature but susceptible to SRAF side lobe issue. Thus, we finally have no choice but to trade-off the advantages of the ideally optimized mask that contains very complicated SRAF patterns to the layout that has been MRC imposed applied to it. The above dilemma can be resolved by simultaneously using lower dose (high threshold) and cleaning up by smaller MRC. This solution makes the room between threshold (side lobe limitation) and MRC constraint (minimum feature limitation) wider. In order to use smaller MRC restriction without considering the mask writing and inspection issue, it is also appropriate to identify the exact mask writing limitation and find the smart mask constraints that well reflect the mask manufacturability and the e-beam lithography characteristics. In this article, we discuss two main topics on mask optimizations with SRAF. The first topic is on the experimental work to find what behavior of the mask writing ability is in term of several MRC parameters, and we propose more effective MRC constraint for aggressive generation of SRAF. The next topic is on finding the optimum MRC condition in practical case, 3X nm node DRAM contact layer. In fact, it is not easy to encompass the mask writing capability for very complicate real SRAF pattern by using the current MRC constraint based on the only width and

  11. Strict constraints on 2D primitive pairs for engineering symbol recognition:Theory and application

    Institute of Scientific and Technical Information of China (English)

    LI Ting; QIU XianJie; HUANG He; WANG ZhaoQi

    2012-01-01

    Geometric constraints on the line-line pair,line-arc pair and arc-arc pair are proposed.The constraints are able to encode the geometric relations between lines,arcs and circles.A geometric proof is presented to demonstrate that the constraints are stable under translation,rotation,uniform scaling or reflection of the primitive pairs.Based on the constraints,an algorithm for recognizing symbols in drawings is developed.Experimental results show that,compared with three other methods,our method can distinguish more primitive pairs and has higher accuracy in engineering symbol recognition.

  12. Applying Motion Constraints Based on Test Data

    Science.gov (United States)

    Burlone, Michael

    2014-01-01

    MSC ADAMS is a simulation software that is used to analyze multibody dynamics. Using user subroutines, it is possible to apply motion constraints to the rigid bodies so that they match the motion profile collected from test data. This presentation describes the process of taking test data and passing it to ADAMS using user subroutines, and uses the Morpheus free-flight 4 test as an example of motion data used for this purpose. Morpheus is the name of a prototype lander vehicle built by NASA that serves as a test bed for various experimental technologies (see backup slides for details) MSC.ADAMS"TM" is used to play back telemetry data (vehicle orientation and position) from each test as the inputs to a 6-DoF general motion constraint (details in backup slides) The MSC.ADAMS"TM" playback simulations allow engineers to examine and analyze flight trajectory as well as observe vehicle motion from any angle and at any playback speed. This facilitates the development of robust and stable control algorithms, increasing reliability and reducing development costs of this developmental engine The simulation also incorporates a 3D model of the artificial hazard field, allowing engineers to visualize and measure performance of the developmental autonomous landing and hazard avoidance technology ADAMS is a multibody dynamics solver. It uses forces, constraints, and mass properties to numerically integrate equations of motion. The ADAMS solver will ask the motion subroutine for position, velocity, and acceleration values at various time steps. Those values must be continuous over the whole time domain. Each degree of freedom in the telemetry data can be examined separately; however, linear interpolation of the telemetry data is invalid, since there will be discontinuities in velocity and acceleration.

  13. Morphodynamics of submarine channel inception revealed by new experimental approach

    Science.gov (United States)

    de Leeuw, Jan; Eggenhuisen, Joris T.; Cartigny, Matthieu J. B.

    2016-03-01

    Submarine channels are ubiquitous on the seafloor and their inception and evolution is a result of dynamic interaction between turbidity currents and the evolving seafloor. However, the morphodynamic links between channel inception and flow dynamics have not yet been monitored in experiments and only in one instance on the modern seafloor. Previous experimental flows did not show channel inception, because flow conditions were not appropriately scaled to sustain suspended sediment transport. Here we introduce and apply new scaling constraints for similarity between natural and experimental turbidity currents. The scaled currents initiate a leveed channel from an initially featureless slope. Channelization commences with deposition of levees in some slope segments and erosion of a conduit in other segments. Channel relief and flow confinement increase progressively during subsequent flows. This morphodynamic evolution determines the architecture of submarine channel deposits in the stratigraphic record and efficiency of sediment bypass to the basin floor.

  14. Design of hydrodynamic performance experimental system of horizontal axis tidal current energy blade%水平轴潮流能桨叶水动力性能实验系统设计

    Institute of Scientific and Technical Information of China (English)

    林躜; 张利; 张惠娣; 陈俊华

    2016-01-01

    Based on the analysis of the characteristics of the impeller’s design for horizontal axis tidal current energy turbine .a 1 kW hydrodynamic performance test system of horizontal axis tidal current energy blade is achieved .The experimental system consists of the making flow subsystem ,tidal current energy capturing subsystem ,transmission subsystem ,measuring and control subsystem and load resistor .It can simulate maximum 2m/s flow velocity .Many hydrodynamic performance tests are supported in the experimental system such as variable tip speed ratio ,mounting angle and wing profile of turbine blade .Using airMAX wireless technology ,the experimental system is capable of wireless remote control and data acquisition , and accomplishes procedure management to monitor the entire experimental system .Under 1 .5 m/s flow velocity energy capture efficiency of blade was tested ,and it is proved that the experimental system is stable ,reliable and easy to control .The experimental system has laid the foundation for blade performance test and wing profile design .%在分析现有水平轴潮流能发电水轮机设计特点的基础上,设计了1 kw水平轴潮流能捕获桨叶水动力性能实验系统。该实验系统由造流子系统、潮流能捕获子系统、传动子系统、测控子系统和负载组成。该系统可模拟2m/s以下潮流,能实现不同尖速比、桨叶安装角、桨叶翼型等多种水动力性能测试研究。该系统应用了无线airM AX技术,能够无线远程控制和数据采集,实现了整个系统的流程化管理和监控。在1.5 m/s模拟潮流下,利用该系统对桨叶的捕能效率进行测试,测试表明系统运行稳定、工作可靠、控制方便。该实验系统奠定了桨叶翼型设计、验证桨叶性能等方面的基础。

  15. LHC constraints and prospects for $S_1$ scalar leptoquark explaining the $\\bar B \\to D^{(*)} \\tau \\bar\

    CERN Document Server

    Dumont, Béranger; Watanabe, Ryoutaro

    2016-01-01

    Recently, deviations in flavor observables of B -> D(*) tau nu have been shown between the predictions in the Standard Model and the experimental results reported by BaBar, Belle, and LHCb collaborations. One of the solutions to this anomaly is obtained in a class of leptoquark model with a scalar leptoquark boson S_1, which is a SU(3)_c triplet and SU(2)_L singlet particle with -1/3 hypercharge interacting with a quark-lepton pair. With well-adjusted couplings, this model can explain the anomaly and be compatible with all flavor constraints. In such a case, the S_1 boson can be pair-produced at CERN's Large Hadron Collider (LHC) and subsequently decay as S_1 -> t tau, b nu, c tau. This paper explores the current 8 and 13 TeV constraints, as well as the detailed prospects at 14 TeV, of this flavor-motivated S_1 model. From the current available 8 and 13 TeV LHC searches, we obtain constraints on the S_1 boson mass for M_{S_1} D(*) tau nu anomaly can be probed with mass less than around 600/800 GeV at the 14 ...

  16. 小电流接地系统实验平台研制和实验内容开发%Experimental Platform and Content Development of Low Current Grounding System

    Institute of Scientific and Technical Information of China (English)

    王庆华; 陈新苗; 贺秋丽

    2013-01-01

    介绍了自行研制的独立的小电流接地系统实验平台的接线和设备选型.论述了自主开发的系统正常运行、单相接地故障、电压互感器故障、铁磁谐振、线路断线、接地故障选线等各项实验内容的原理和方法.实验平台适用于课程实验、专业综合实验、创新实验以及毕业设计各个教学环节,且成本低廉,通用性强.%The construction of an experimental platform of low current grounding system and the strengthening of practice teaching is of great importance in the cultivation of innovation and application-oriented talents. This paper introduces the function and. wiring diagram of an experimental platform of low current grounding system, and expatiates the content principle and method of each experiment, such as system normal operation, single-phase grounding fault, voltage transformer breakdown, ferromagnetic resonance, line broken and grounding fault selection. This experimental platform is appropriate for the electrical specialty in universities.

  17. Interferometric Constraints on Quantum Geometrical Shear Noise Correlations

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Aaron; Glass, Henry; Gustafson, H. Richard; Hogan, Craig J.; Kamai, Brittany L.; Kwon, Ohkyung; Lanza, Robert; McCuller, Lee; Meyer, Stephan S.; Richardson, Jonathan W.; Stoughton, Chris; Tomlin, Ray; Weiss, Rainer

    2017-03-24

    Final measurements and analysis are reported from the first-generation Holometer, the first instrument capable of measuring correlated variations in space-time position at strain noise power spectral densities smaller than a Planck time. The apparatus consists of two co-located, but independent and isolated, 40 m power-recycled Michelson interferometers, whose outputs are cross-correlated to 25 MHz. The data are sensitive to correlations of differential position across the apparatus over a broad band of frequencies up to and exceeding the inverse light crossing time, 7.6 MHz. By measuring with Planck precision the correlation of position variations at spacelike separations, the Holometer searches for faint, irreducible correlated position noise backgrounds predicted by some models of quantum space-time geometry. The first-generation optical layout is sensitive to quantum geometrical noise correlations with shear symmetry---those that can be interpreted as a fundamental noncommutativity of space-time position in orthogonal directions. General experimental constraints are placed on parameters of a set of models of spatial shear noise correlations, with a sensitivity that exceeds the Planck-scale holographic information bound on position states by a large factor. This result significantly extends the upper limits placed on models of directional noncommutativity by currently operating gravitational wave observatories.

  18. Interferometric constraints on quantum geometrical shear noise correlations

    Science.gov (United States)

    Chou, Aaron; Glass, Henry; Gustafson, H. Richard; Hogan, Craig J.; Kamai, Brittany L.; Kwon, Ohkyung; Lanza, Robert; McCuller, Lee; Meyer, Stephan S.; Richardson, Jonathan W.; Stoughton, Chris; Tomlin, Ray; Weiss, Rainer

    2017-08-01

    Final measurements and analysis are reported from the first-generation Holometer, the first instrument capable of measuring correlated variations in space-time position at strain noise power spectral densities smaller than a Planck time. The apparatus consists of two co-located, but independent and isolated, 40 m power-recycled Michelson interferometers, whose outputs are cross-correlated to 25 MHz. The data are sensitive to correlations of differential position across the apparatus over a broad band of frequencies up to and exceeding the inverse light crossing time, 7.6 MHz. By measuring with Planck precision the correlation of position variations at spacelike separations, the Holometer searches for faint, irreducible correlated position noise backgrounds predicted by some models of quantum space-time geometry. The first-generation optical layout is sensitive to quantum geometrical noise correlations with shear symmetry—those that can be interpreted as a fundamental noncommutativity of space-time position in orthogonal directions. General experimental constraints are placed on parameters of a set of models of spatial shear noise correlations, with a sensitivity that exceeds the Planck-scale holographic information bound on position states by a large factor. This result significantly extends the upper limits placed on models of directional noncommutativity by currently operating gravitational wave observatories.

  19. Experimental animal model of gastric cancer: an overview of current research%胃癌实验动物模型的研究概况

    Institute of Scientific and Technical Information of China (English)

    张继燃

    2013-01-01

    Stomach cancer is one of the most common malignant tumors,so the establishment of a reliable animal model of this disease has important significance in elucidating its causes and pathogenesis as well as screening the prevention and treatment drugs.At present,the animal models of gastric cancer,according to the level and purpose of study,are classified into long-term induction model,rapid xenograft tumor formation model and other specific models.This paper overviews the current status of the available animal models with regard to the animal selection,creation methods,and scope of application,etc.%胃癌是最常见的恶性肿瘤之一,故建立可靠的胃癌动物模型对于探明胃癌的病因、发病机制及防治药物的研究均具有重要意义.目前,根据不同的研究水平及研究目的,胃癌动物模型可分为长期诱导型、快速移植型及其他特殊模型等,本文就胃癌动物模型的动物选择、造模方法、适用范围等的研究现状进行综述.

  20. Experimental Characterisation of the Interfacial Structure during Counter-Current Flow Limitation in a Model of the Hot Leg of a PWR

    Directory of Open Access Journals (Sweden)

    Christophe Vallée

    2012-01-01

    Full Text Available In order to investigate the two-phase flow behaviour during counter-current flow limitation in the hot leg of a pressurised water reactor, dedicated experiments were performed in a scaled down model of Kobe University. The experiments were performed with air and water at atmospheric pressure and room temperature. At high flow rates, CCFL occurs and the discharge of water to the reactor pressure vessel simulator is limited by the formation of slugs carrying liquid back to the steam generator. The structure of the interface was observed from the side of the channel test section using a high-speed video camera. An algorithm was developed to recognise the stratified interface in the camera frames after background subtraction. This method allows extracting the water level at any position in the image as well as performing further statistical treatments. The evolution of the interfacial structure along the horizontal part of the hot leg is shown by the visualisation of the probability distribution of the water level and analysed in function of the liquid and gas flow rates. The data achieved are useful for the analysis of the flow conditions as well as for the validation of modelling approaches like computational fluid dynamics.

  1. Validación Experimental de la Metodología Motor Current Signature Analysis para un Motor de Inducción de 2 HP

    Directory of Open Access Journals (Sweden)

    Silvia J. Oviedo

    2014-01-01

    Full Text Available El análisis de las corrientes de estator en la monitorización de máquinas eléctricas rotativas, particularmente en motores de inducción, ha tenido un creciente interés, debido a que la información contenida en el espectro de la señal de corriente puede indicar la presencia de diversos tipos de fallas tanto eléctricas como mecánicas. En este trabajo se implementó un banco de pruebas para motores de inducción de 2 HP con el fin de validar la metodología MCSA (Motor Current Signature Analysis para la detección de: corto circuito en el devanado del estator, barras de rotor rotas y excentricidad del entrehierro bajo distintas condiciones de carga. Los resultados dejan ver el grado de dependencia entre la condición de carga del motor con falla y la posibilidad de detección de la misma, así como evaluar la viabilidad de la implementación de dicha metodología en los esquemas de mantenimiento basado en la condición (CBM.

  2. Design, theoretical analysis, and experimental verification of a CMOS current integrator with 1.2 × 2.05 µm2 microelectrode array for high-sensitivity bacterial counting

    Science.gov (United States)

    Gamo, Kohei; Nakazato, Kazuo; Niitsu, Kiichi

    2017-01-01

    In this paper, we present the design and experimental verification of an amperometric CMOS-based sensor with a current integrator and a 1.2 × 2.05 µm2 bacterial-sized microelectrode array for high-sensitivity bacterial counting. For high-sensitivity bacterial counting with a sufficient signal-to-noise ratio (SNR), noise must be reduced because bacterial-sized microelectrodes can handle only a low current of the order of 100 pA. Thus, we implement a current integrator that is highly effective for noise reduction. Furthermore, for the first time, we use the current integrator in conjunction with the bacterial-sized microelectrode array. On the basis of the results of the proposed current integration, we successfully reduce noise and achieve a high SNR of 30.4 dB. To verify the effectiveness of the proposed CMOS-based sensor, we perform two-dimensional counting of microbeads, which are almost of the same size as bacteria. The measurement results demonstrate successful high-sensitivity two-dimensional (2D) counting of microbeads with a high SNR of 27 dB.

  3. Taxes and financial constraints : Evidence from linguistic cues

    NARCIS (Netherlands)

    Law, Kelvin; Mills, L.F.

    2015-01-01

    Using a new measure of financial constraints based on firms’ qualitative disclosures, we find that financially constrained firms—firms that use more negative words in their annual reports—pursue more aggressive tax planning strategies as evidenced by: (1) higher current and future unrecognized tax b

  4. Constraint-Induced Movement Therapy (CIMT): Pediatric Applications

    Science.gov (United States)

    Brady, Kathleen; Garcia, Teressa

    2009-01-01

    The purpose of this article is to describe theoretical and research bases for constraint-induced movement therapy (CIMT), to discuss key features and variations in protocols currently in use with children, and to review the results of studies of efficacy. CIMT has been found to be an effective intervention for increasing functional use of the…

  5. Taxes and financial constraints : Evidence from linguistic cues

    NARCIS (Netherlands)

    Law, Kelvin; Mills, L.F.

    2015-01-01

    Using a new measure of financial constraints based on firms’ qualitative disclosures, we find that financially constrained firms—firms that use more negative words in their annual reports—pursue more aggressive tax planning strategies as evidenced by: (1) higher current and future unrecognized tax b

  6. Intertemporal consumption and credit constraints

    DEFF Research Database (Denmark)

    Leth-Petersen, Søren

    2010-01-01

    There is continuing controversy over the importance of credit constraints. This paper investigates whether total household expenditure and debt is affected by an exogenous increase in access to credit provided by a credit market reform that enabled Danish house owners to use housing equity as col...

  7. Perceptual Constraints in Phonotactic Learning

    Science.gov (United States)

    Endress, Ansgar D.; Mehler, Jacques

    2010-01-01

    Structural regularities in language have often been attributed to symbolic or statistical general purpose computations, whereas perceptual factors influencing such generalizations have received less interest. Here, we use phonotactic-like constraints as a case study to ask whether the structural properties of specific perceptual and memory…

  8. Sterile neutrino constraints from cosmology

    DEFF Research Database (Denmark)

    Hamann, Jan; Hannestad, Steen; Raffelt, Georg G.

    2012-01-01

    The presence of light particles beyond the standard model's three neutrino species can profoundly impact the physics of decoupling and primordial nucleosynthesis. I review the observational signatures of extra light species, present constraints from recent data, and discuss the implications...... of possible sterile neutrinos with O(eV)-masses for cosmology....

  9. Sterile neutrino constraints from cosmology

    DEFF Research Database (Denmark)

    Hamann, Jan; Hannestad, Steen; Raffelt, Georg G.;

    2012-01-01

    The presence of light particles beyond the standard model's three neutrino species can profoundly impact the physics of decoupling and primordial nucleosynthesis. I review the observational signatures of extra light species, present constraints from recent data, and discuss the implications of po...

  10. Constraint-based facial animation

    NARCIS (Netherlands)

    Z.M. Ruttkay

    1999-01-01

    textabstractConstraints have been traditionally used for computer animation applications to define side conditions for generating synthesized motion according to a standard, usually physically realistic, set of motion equations. The case of facial animation is very different, as no set of motion equ

  11. Constraint-induced movement therapy

    DEFF Research Database (Denmark)

    Castellini, Greta; Gianola, Silvia; Banzi, Rita;

    2014-01-01

    on randomized controlled trials (RCTs) included in a Cochrane systematic review on the effectiveness of constraint-induced movement therapy (CIMT) for stroke patients. METHODS: We extracted data on the functional independence measure (FIM) and the action research arm test (ARAT) from RCTs that compared CIMT...

  12. Constraint Programming versus Mathematical Programming

    DEFF Research Database (Denmark)

    Hansen, Jesper

    2003-01-01

    Constraint Logic Programming (CLP) is a relatively new technique from the 80's with origins in Computer Science and Artificial Intelligence. Lately, much research have been focused on ways of using CLP within the paradigm of Operations Research (OR) and vice versa. The purpose of this paper...

  13. Constraint-based facial animation

    NARCIS (Netherlands)

    Z.M. Ruttkay

    1999-01-01

    textabstractConstraints have been traditionally used for computer animation applications to define side conditions for generating synthesized motion according to a standard, usually physically realistic, set of motion equations. The case of facial animation is very different, as no set of motion

  14. A proof for loop-law constraints in stoichiometric metabolic networks

    Directory of Open Access Journals (Sweden)

    Noor Elad

    2012-11-01

    Full Text Available Abstract Background Constraint-based modeling is increasingly employed for metabolic network analysis. Its underlying assumption is that natural metabolic phenotypes can be predicted by adding physicochemical constraints to remove unrealistic metabolic flux solutions. The loopless-COBRA approach provides an additional constraint that eliminates thermodynamically infeasible internal cycles (or loops from the space of solutions. This allows the prediction of flux solutions that are more consistent with experimental data. However, it is not clear if this approach over-constrains the models by removing non-loop solutions as well. Results Here we apply Gordan’s theorem from linear algebra to prove for the first time that the constraints added in loopless-COBRA do not over-constrain the problem beyond the elimination of the loops themselves. Conclusions The loopless-COBRA constraints can be reliably applied. Furthermore, this proof may be adapted to evaluate the theoretical soundness for other methods in constraint-based modeling.

  15. Registering aerial video images using the projective constraint.

    Science.gov (United States)

    Jackson, Brian P; Goshtasby, A Ardeshir

    2010-03-01

    To separate object motion from camera motion in an aerial video, consecutive frames are registered at their planar background. Feature points are selected in consecutive frames and those that belong to the background are identified using the projective constraint. Corresponding background feature points are then used to register and align the frames. By aligning video frames at the background and knowing that objects move against the background, a means to detect and track moving objects is provided. Only scenes with planar background are considered in this study. Experimental results show improvement in registration accuracy when using the projective constraint to determine the registration parameters as opposed to finding the registration parameters without the projective constraint.

  16. A Data Flow Behavior Constraints Model for Branch Decisionmaking Variables

    Directory of Open Access Journals (Sweden)

    Lu Yan

    2012-06-01

    Full Text Available In order to detect the attacks to decision-making variable, this paper presents a data flow behavior constraint model for branch decision-making variables. Our model is expanded from the common control flow model, itemphasizes on the analysis and verification about the data flow for decision-making variables, so that to ensure the branch statement can execute correctly and can also detect the attack to branch decision-making variableeasily. The constraints of our model include the collection of variables, the statements that the decision-making variables are dependent on and the data flow constraint with the use-def relation of these variables. Our experimental results indicate that it is effective in detecting the attacks to branch decision-making variables as well as the attacks to control-data.

  17. Observational constraints on extended Chaplygin gas cosmologies

    Indian Academy of Sciences (India)

    B C PAUL; P THAKUR; A SAHA

    2017-08-01

    We investigate cosmological models with extended Chaplygin gas (ECG) as a candidate for dark energy and determine the equation of state parameters using observed data namely, observed Hubble data, baryon acousticoscillation data and cosmic microwave background shift data. Cosmological models are investigated considering cosmic fluid which is an extension of Chaplygin gas, however, it reduces to modified Chaplygin gas (MCG) andalso to generalized Chaplygin gas (GCG) in special cases. It is found that in the case of MCG and GCG, the best-fit values of all the parameters are positive. The distance modulus agrees quite well with the experimental Union2data. The speed of sound obtained in the model is small, necessary for structure formation. We also determine the observational constraints on the constants of the ECG equation.

  18. Current progresses of experimental models of amblyopia and clinical therapeutic%弱视的实验研究及临床治疗展望

    Institute of Scientific and Technical Information of China (English)

    李少敏(综述)

    2014-01-01

    弱视是一种儿童早期由于异常的视觉经历如斜视,屈光参差,视觉剥夺等导致的皮层性视觉损害,因而,只有理解了其发病的神经机制,才可能提出有效的治疗。一般观念认为弱视只有在儿童期治疗才有效,而成人的弱视基本无法治愈,但是近年来随着对弱视发病机制的分子生物学及神经电生理的研究,尤其是对视觉皮层发育可塑性的细胞间交流及细胞内分子信号通路的认识,拓展了人们对弱视病理的知识,因而也成功地通过恢复成年期的可塑性改善了成年弱视的视力。本文介绍了视觉发育可塑性的进展,就近年在增强成年可塑性途径如改变神经兴奋性与抑制性的平衡、细胞外基质、丰富环境及表观遗传学修饰等作了介绍,以其对弱视的病理机制,尤其对成人弱视的治疗有更深入的认识。%Amblyopia is a form of cerebral visual impairment caused by abnormal visual experience ( e.g., strabismus, anisometropia, deprivation) during early childhood. It is essential to understand the neural mechanism of amblyopia in order to devise novel therapeutic strategies. Although previous concepts of amblyopia is an untreatable pathology in adults, recent data deepen our knowledge of the factors involved in the intercellular communication and intracellular signaling that mediate experience-dependent plasticity in the developing visual cortex. Successful en-hancement of adult plasticity has been achieved by altering the excitation to inhibition balance;extracellular matrices;environmental enrichment and epigenetic modification. In this review, I describe current concepts of brain plasticity and the established mechanisms of amblyopia, and their implications for novel therapeutic strategies, these may hold the best hope for success in the fight against amblyopia.

  19. Creativity from Constraints in Engineering Design

    DEFF Research Database (Denmark)

    Onarheim, Balder

    2012-01-01

    This paper investigates the role of constraints in limiting and enhancing creativity in engineering design. Based on a review of literature relating constraints to creativity, the paper presents a longitudinal participatory study from Coloplast A/S, a major international producer of disposable......, removal, introducing and revising. Constraints introduced late in a project contributed to the generation of new solutions to old problems, and existing solutions were creatively adopted to satisfy new constraints. This paper recommends creative constraint-handling strategies, as well as identifying...... potential directions for future research on the relationship between creativity and constraints...

  20. An SQP algorithm for mathematical programs with nonlinear complementarity constraints

    Institute of Scientific and Technical Information of China (English)

    Zhi-bin ZHU; Jin-bao JIAN; Cong ZHANG

    2009-01-01

    In this paper,we describe a successive approximation and smooth sequential quadratic programming (SQP) method for mathematical programs with nonlinear complementarity constraints (MPCC). We introduce a class of smooth programs to approximate the MPCC. Using an l1 penalty function,the line search assures global convergence,while the superlinear convergence rate is shown under the strictly complementary and second-order sufficient conditions. Moreover,we prove that the current iterated point is an exact stationary point of the mathematical programs with equilibrium constraints (MPEC) when the algorithm terminates finitely.

  1. Cosmological constraints on the generalized holographic dark energy

    CERN Document Server

    Lu, Jianbo; Wu, Yabo; Wang, Tianqiang

    2012-01-01

    We use the Markov ChainMonte Carlo method to investigate global constraints on the generalized holographic (GH) dark energy with flat and non-flat universe from the current observed data: the Union2 dataset of type supernovae Ia (SNIa), high-redshift Gamma-Ray Bursts (GRBs), the observational Hubble data (OHD), the cluster X-ray gas mass fraction, the baryon acoustic oscillation (BAO), and the cosmic microwave background (CMB) data. The most stringent constraints on the GH model parameter are obtained. In addition, it is found that the equation of state for this generalized holographic dark energy can cross over the phantom boundary wde =-1.

  2. Observational Constraints on Exponential Gravity

    CERN Document Server

    Yang, Louis; Luo, Ling-Wei; Geng, Chao-Qiang

    2010-01-01

    We study the observational constraints on the exponential gravity model of f(R)=-beta*Rs(1-e^(-R/Rs)). We use the latest observational data including Supernova Cosmology Project (SCP) Union2 compilation, Two-Degree Field Galaxy Redshift Survey (2dFGRS), Sloan Digital Sky Survey Data Release 7 (SDSS DR7) and Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP7) in our analysis. From these observations, we obtain a lower bound on the model parameter beta at 1.27 (95% CL) but no appreciable upper bound. The constraint on the present matter density parameter is 0.245< Omega_m^0<0.311 (95% CL). We also find out the best-fit value of model parameters on several cases.

  3. A Compendium of Chameleon Constraints

    CERN Document Server

    Burrage, Clare

    2016-01-01

    The chameleon model is a scalar field theory with a screening mechanism that explains how a cosmologically relevant light scalar can avoid the constraints of intra-solar-system searches for fifth-forces. The chameleon is a popular dark energy candidate and also arises in $f(R)$ theories of gravity. Whilst the chameleon is designed to avoid historical searches for fifth-forces it is not unobservable and much effort has gone into identifying the best observables and experiments to detect it. These results are not always presented for the same models or in the same language, a particular problem when comparing astrophysical and laboratory searches making it difficult to understand what regions of parameter space remain. Here we present combined constraints on the chameleon model from astrophysical and laboratory searches for the first time and identify the remaining windows of parameter space. We discuss the implications for cosmological chameleon searches and future small-scale probes.

  4. A compendium of chameleon constraints

    Science.gov (United States)

    Burrage, Clare; Sakstein, Jeremy

    2016-11-01

    The chameleon model is a scalar field theory with a screening mechanism that explains how a cosmologically relevant light scalar can avoid the constraints of intra-solar-system searches for fifth-forces. The chameleon is a popular dark energy candidate and also arises in f(R) theories of gravity. Whilst the chameleon is designed to avoid historical searches for fifth-forces it is not unobservable and much effort has gone into identifying the best observables and experiments to detect it. These results are not always presented for the same models or in the same language, a particular problem when comparing astrophysical and laboratory searches making it difficult to understand what regions of parameter space remain. Here we present combined constraints on the chameleon model from astrophysical and laboratory searches for the first time and identify the remaining windows of parameter space. We discuss the implications for cosmological chameleon searches and future small-scale probes.

  5. Self-Imposed Creativity Constraints

    DEFF Research Database (Denmark)

    Biskjaer, Michael Mose

    2013-01-01

    Abstract This dissertation epitomizes three years of research guided by the research question: how can we conceptualize creative self-binding as a resource in art and design processes? Concretely, the dissertation seeks to offer insight into the puzzling observation that highly skilled creative...... practitioners sometimes freely and intentionally impose rigid rules, peculiar principles, and other kinds of creative obstructions on themselves as a means to spur momentum in the process and reach a distinctly original outcome. To investigate this the dissertation is composed of four papers (Part II) framed...... of analysis. Informed by the insight that constraints both enable and restrain creative agency, the dissertation’s main contention is that creative self- binding may profitably be conceptualized as the exercise of self-imposed creativity constraints. Thus, the dissertation marks an analytical move from vague...

  6. An analysis of constraints on access to augmentative communication in cerebral palsy.

    Science.gov (United States)

    Costigan, F Aileen; Newell, Karl M

    2009-06-01

    Effective use of augmentative communication requires an individual to manage its technical aspects. Motor-skill limitations in cerebral palsy (i.e., individual constraints) can influence this ability as can demands imposed by communication devices (i.e., task constraints). This paper emphasizes the importance of analyzing the confluence of task and individual constraints in promoting a functional fit between the individual with cerebral palsy and the communication device. We demonstrate the utility of current principles of motor control in analyzing this confluence. Task constraints imposed by target selection and individual constraints imposed by cerebral palsy are introduced prior to an analysis of their confluence using the degrees of freedom of the potential planes of limb motion. Occupational therapists should look beyond motor-skill assessment to the confluence of task and individual constraints when customizing target selection in augmentative communication.

  7. Deepening Contractions and Collateral Constraints

    DEFF Research Database (Denmark)

    Jensen, Henrik; Ravn, Søren Hove; Santoro, Emiliano

    on the differential impact that occasionally non-binding constraints exert on the shape of expansions and contractions, we are also able to reconcile a more negatively skewed business cycle with a moderation in its volatility. Finally, our model can account for an intrinsic feature of economic downturns preceded...... by private credit build-ups: Financially driven expansions lead to deeper contractions, as compared to equally-sized non-financial expansions....

  8. Causality constraints on TMD PDF

    CERN Document Server

    Efremov, A V

    2013-01-01

    In this short note, we discuss constraints on the transverse momentum dependent factorization formulae coming from the causality properties for the hadronic tensor. We show that the range of definition of the TMD PDFs in the transverse coordinate plane is wider that it is allowed by the causality. It indicates the presents of the large compensating corrections for the TMD PDF factorization theorem and/or overestimation of the transverse component dependence of TMD PDF.

  9. Expressing Preferences using Preference Set Constraint Atoms

    CERN Document Server

    Brik, Alex

    2012-01-01

    This paper introduces an extension of Answer Set Programming called Preference Set Constraint Programming which is a convenient and general formalism to reason with preferences. PSC programming extends Set Constraint Programming introduced by Marek and Remmel (Marek and Remmel 2004) by introducing two types of preference set constraint atoms, measure preference set constraint atoms and pre-ordered preference set constraint atoms, which are extensions of set constraint atoms. We show that the question of whether a PSC program has a preferred stable model is CoNP-complete. We give examples of the uses of the preference set constraint atoms and show that Answer Set Optimization (Brewka, Niemel\\"a, and Truszczynski 2003) and General Preference (Son and Pontelli 2006) can be expressed using preference set constraint atoms.

  10. Relaxations of semiring constraint satisfaction problems

    CSIR Research Space (South Africa)

    Leenen, L

    2007-03-01

    Full Text Available The Semiring Constraint Satisfaction Problem (SCSP) framework is a popular approach for the representation of partial constraint satisfaction problems. In this framework preferences can be associated with tuples of values of the variable domains...

  11. Solving Topological and Geometrical Constraints in Bridge Feature Model

    Institute of Scientific and Technical Information of China (English)

    PENG Weibing; SONG Liangliang; PAN Guoshuai

    2008-01-01

    The capacity that computer can solve more complex design problem was gradually increased.Bridge designs need a breakthrough in the current development limitations, and then become more intelli-gent and integrated. This paper proposes a new parametric and feature-based computer aided design (CAD) models which can represent families of bridge objects, includes knowledge representation, three-dimensional geometric topology relationships. The realization of a family member is found by solving first the geometdc constraints, and then the topological constraints. From the geometric solution, constraint equations are constructed. Topology solution is developed by feature dependencies graph between bridge objects. Finally, feature parameters are proposed to drive bridge design with feature parameters. Results from our implementation show that the method can help to facilitate bridge design.

  12. Cosmological and astrophysical constraints on tachyon dark energy models

    CERN Document Server

    Martins, C J A P

    2016-01-01

    Rolling tachyon field models are among the candidates suggested as explanations for the recent acceleration of the Universe. In these models the field is expected to interact with gauge fields and lead to variations of the fine-structure constant $\\alpha$. Here we take advantage of recent observational progress and use a combination of background cosmological observations of Type Ia supernovas and astrophysical and local measurements of $\\alpha$ to improve constraints on this class of models. We show that the constraints on $\\alpha$ imply that the field dynamics must be extremely slow, leading to a constraint of the present-day dark energy equation of state $(1+w_0)<2.4\\times10^{-7}$ at the $99.7\\%$ confidence level. Therefore current and forthcoming standard background cosmology observational probes can't distinguish this class of models from a cosmological constant, while detections of $\\alpha$ variations could possibly do so since they would have a characteristic redshift dependence.

  13. Cosmological and astrophysical constraints on tachyon dark energy models

    Science.gov (United States)

    Martins, C. J. A. P.; Moucherek, F. M. O.

    2016-06-01

    Rolling tachyon field models are among the candidates suggested as explanations for the recent acceleration of the Universe. In these models the field is expected to interact with gauge fields and lead to variations of the fine-structure constant α . Here we take advantage of recent observational progress and use a combination of background cosmological observations of type Ia supernovas and astrophysical and local measurements of α to improve constraints on this class of models. We show that the constraints on α imply that the field dynamics must be extremely slow, leading to a constraint of the present-day dark energy equation of state (1 +w0)<2.4 ×10-7 at the 99.7% confidence level. Therefore current and forthcoming standard background cosmology observational probes cannot distinguish this class of models from a cosmological constant, while detections of α variations could possibly do so since they would have a characteristic redshift dependence.

  14. Closure constraints for hyperbolic tetrahedra

    CERN Document Server

    Charles, Christoph

    2015-01-01

    We investigate the generalization of loop gravity's twisted geometries to a q-deformed gauge group. In the standard undeformed case, loop gravity is a formulation of general relativity as a diffeomorphism-invariant SU(2) gauge theory. Its classical states are graphs provided with algebraic data. In particular closure constraints at every node of the graph ensure their interpretation as twisted geometries. Dual to each node, one has a polyhedron embedded in flat space R^3. One then glues them allowing for both curvature and torsion. It was recently conjectured that q-deforming the gauge group SU(2) would allow to account for a non-vanishing cosmological constant Lambda, and in particular that deforming the loop gravity phase space with real parameter q>0 would lead to a generalization of twisted geometries to a hyperbolic curvature. Following this insight, we look for generalization of the closure constraints to the hyperbolic case. In particular, we introduce two new closure constraints for hyperbolic tetrahe...

  15. Updating neutrino magnetic moment constraints

    Directory of Open Access Journals (Sweden)

    B.C. Cañas

    2016-02-01

    Full Text Available In this paper we provide an updated analysis of the neutrino magnetic moments (NMMs, discussing both the constraints on the magnitudes of the three transition moments Λi and the role of the CP violating phases present both in the mixing matrix and in the NMM matrix. The scattering of solar neutrinos off electrons in Borexino provides the most stringent restrictions, due to its robust statistics and the low energies observed, below 1 MeV. Our new limit on the effective neutrino magnetic moment which follows from the most recent Borexino data is 3.1×10−11μB at 90% C.L. This corresponds to the individual transition magnetic moment constraints: |Λ1|≤5.6×10−11μB, |Λ2|≤4.0×10−11μB, and |Λ3|≤3.1×10−11μB (90% C.L., irrespective of any complex phase. Indeed, the incoherent admixture of neutrino mass eigenstates present in the solar flux makes Borexino insensitive to the Majorana phases present in the NMM matrix. For this reason we also provide a global analysis including the case of reactor and accelerator neutrino sources, presenting the resulting constraints for different values of the relevant CP phases. Improved reactor and accelerator neutrino experiments will be needed in order to underpin the full profile of the neutrino electromagnetic properties.

  16. Geometric constraint solving with geometric transformation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper proposes two algorithms for solving geometric constraint systems. The first algorithm is for constrained systems without loops and has linear complexity. The second algorithm can solve constraint systems with loops. The latter algorithm is of quadratic complexity and is complete for constraint problems about simple polygons. The key to it is to combine the idea of graph based methods for geometric constraint solving and geometric transformations coming from rule-based methods.

  17. Ant colony optimization and constraint programming

    CERN Document Server

    Solnon, Christine

    2013-01-01

    Ant colony optimization is a metaheuristic which has been successfully applied to a wide range of combinatorial optimization problems. The author describes this metaheuristic and studies its efficiency for solving some hard combinatorial problems, with a specific focus on constraint programming. The text is organized into three parts. The first part introduces constraint programming, which provides high level features to declaratively model problems by means of constraints. It describes the main existing approaches for solving constraint satisfaction problems, including complete tree search

  18. Astrophysical Constraints on Planck Scale Dissipative Phenomena

    Science.gov (United States)

    Liberati, Stefano; Maccione, Luca

    2014-04-01

    The emergence of a classical spacetime from any quantum gravity model is still a subtle and only partially understood issue. If indeed spacetime is arising as some sort of large scale condensate of more fundamental objects, then it is natural to expect that matter, being a collective excitation of the spacetime constituents, will present modified kinematics at sufficiently high energies. We consider here the phenomenology of the dissipative effects necessarily arising in such a picture. Adopting dissipative hydrodynamics as a general framework for the description of the energy exchange between collective excitations and the spacetime fundamental degrees of freedom, we discuss how rates of energy loss for elementary particles can be derived from dispersion relations and used to provide strong constraints on the base of current astrophysical observations of high-energy particles.

  19. Implementing network constraints in the EMPS model

    Energy Technology Data Exchange (ETDEWEB)

    Helseth, Arild; Warland, Geir; Mo, Birger; Fosso, Olav B.

    2010-02-15

    This report concerns the coupling of detailed market and network models for long-term hydro-thermal scheduling. Currently, the EPF model (Samlast) is the only tool available for this task for actors in the Nordic market. A new prototype for solving the coupled market and network problem has been developed. The prototype is based on the EMPS model (Samkjoeringsmodellen). Results from the market model are distributed to a detailed network model, where a DC load flow detects if there are overloads on monitored lines or intersections. In case of overloads, network constraints are generated and added to the market problem. Theoretical and implementation details for the new prototype are elaborated in this report. The performance of the prototype is tested against the EPF model on a 20-area Nordic dataset. (Author)

  20. Cosmological constraints on coupled dark energy

    CERN Document Server

    Yang, Weiqiang; Wu, Yabo; Lu, Jianbo

    2016-01-01

    The coupled dark energy model provides a possible approach to mitigate the coincidence problem of cosmological standard model. Here, the coupling term is assumed as $\\bar{Q}=3H\\xi_x\\bar{\\rho}_x$, which is related to the interaction rate and energy density of dark energy. We derive the background and perturbation evolution equations for several coupled models. Then, we test these models by currently available cosmic observations which include cosmic microwave background radiation from Planck 2015, baryon acoustic oscillation, type Ia supernovae, $f\\sigma_8(z)$ data points from redshift-space distortions, and weak gravitational lensing. The constraint results tell us the interaction rate is close to zero in 1$\\sigma$ region, it is very hard to distinguish different coupled models from other ones.