WorldWideScience

Sample records for bents

  1. Construction of bent functions from near-bent functions

    DEFF Research Database (Denmark)

    Leander, Gregor; McGuire, G.

    2009-01-01

    We give a construction of bent functions in dimension 2m from near-bent functions in dimension 2m - 1. in particular, we give the first ever examples of non-weakly-normal bent functions in dimensions 10 and 12, which demonstrates the significance of our construction.......We give a construction of bent functions in dimension 2m from near-bent functions in dimension 2m - 1. in particular, we give the first ever examples of non-weakly-normal bent functions in dimensions 10 and 12, which demonstrates the significance of our construction....

  2. Some Properties of Bent Functions

    Institute of Scientific and Technical Information of China (English)

    Ying Zhao

    2007-01-01

    First, this paper discusses and sums up some properties of a pair of functions p(x), q(x) that makes (y + 1)p(x) + yq(x) into a bent function. Then it discusses the properties of bent functions. Also, the upper and lower bounds of the number of bent functions on GF(2)2k are discussed.

  3.   Bente Boa, Torm, Denmark

    DEFF Research Database (Denmark)

    Wagtmann, Maria Anne

    2009-01-01

    At the beginning of July 2009, Maria Anne Wagtmann (Associate Professor, PhD, University of Southern Denmark) had the opportunity to interview Ms Bente Boa, a senior marine HR manager in the Danish ship owning firm TORM A/S' ( http://www.torm.com/ ). Bente Boa is also chairwoman of the "The Sea...

  4. A new construction of bent functions based on Z-bent functions

    DEFF Research Database (Denmark)

    Gangopadhyay, Sugata; Joshi, Anand; Leander, Gregor;

    2013-01-01

    Dobbertin has embedded the problem of construction of bent functions in a recursive framework by using a generalization of bent functions called -bent functions. Following his ideas, we generalize the construction of partial spreads bent functions to partial spreads -bent functions of arbitrary...... level. Furthermore, we show how these partial spreads -bent functions give rise to a new construction of (classical) bent functions. Further, we construct a bent function on 8 variables which is inequivalent to all Maiorana-McFarland as well as PS ap type bents. It is also shown that all bent functions...

  5. Bent Marshak Waves

    Energy Technology Data Exchange (ETDEWEB)

    Hurricane, O A; Hammer, J H

    2005-10-11

    Radiation driven heat waves (Marshak Waves) are ubiquitous in astrophysics and terrestrial laser driven high energy density plasma physics (HEDP) experiments. Generally, the equations describing Marshak waves are so nonlinear, that solutions involving more than one spatial dimension require simulation. However, in this paper we show how one may analytically solve the problem of the two-dimensional nonlinear evolution of a Marshak wave, bounded by lossy walls, using an asymptotic expansion in a parameter related to the wall albedo and a simplification of the heat front equation of motion. Three parameters determine the nonlinear evolution, a modified Markshak diffusion constant, a smallness parameter related to the wall albedo, and the spacing of the walls. The final nonlinear solution shows that the Marshak wave will be both slowed and bent by the non-ideal boundary. In the limit of a perfect boundary, the solution recovers the original diffusion-like solution of Marshak. The analytic solution will be compared to a limited set of simulation results and experimental data.

  6. Relationship between Multi-Output Partially Bent Functions and Multi-Output Bent Functions

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yaqun; JU Guizhi; WANG Jue

    2006-01-01

    In this paper, the definition of multi-output partially Bent functions is presented and some properties are discussed. Then the relationship between multi-output partially Bent functions and multi-output Bent functions is given in Theorem 4, which includes Walsh spectrum expression and function expression. This shows that multi-output partially Bent functions and multi-output Bent functions can define each other in principle. So we obtain the general method to construct multi-output partially Bent functions from multi-output Bent functions.

  7. Ion implantation for manufacturing bent and periodically bent crystals

    Energy Technology Data Exchange (ETDEWEB)

    Bellucci, Valerio; Camattari, Riccardo; Guidi, Vincenzo, E-mail: guidi@fe.infn.it; Mazzolari, Andrea; Paternò, Gianfranco [Department of Physics and Earth Sciences, University of Ferrara, Via Saragat 1/c, 44122 Ferrara, Italy and INFN, Section of Ferrara (Italy); Mattei, Giovanni, E-mail: giovanni.mattei@unipd.it; Scian, Carlo [Department of Physics and Astronomy Galileo Galilei, University of Padova, Via Marzolo 8, 35131 Padova (Italy); Lanzoni, Luca [Dipertimento di Economia e Tecnologia, Università degli Studi della Repubblica di San Marino, Salita alla Rocca, 44, 47890 San Marino Città (San Marino)

    2015-08-10

    Ion implantation is proposed to produce self-standing bent monocrystals. A Si sample 0.2 mm thick was bent to a radius of curvature of 10.5 m. The sample curvature was characterized by interferometric measurements; the crystalline quality of the bulk was tested by X-ray diffraction in transmission geometry through synchrotron light at ESRF (Grenoble, France). Dislocations induced by ion implantation affect only a very superficial layer of the sample, namely, the damaged region is confined in a layer 1 μm thick. Finally, an elective application of a deformed crystal through ion implantation is here proposed, i.e., the realization of a crystalline undulator to produce X-ray beams.

  8. Bent functions results and applications to cryptography

    CERN Document Server

    Tokareva, Natalia

    2015-01-01

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

  9. Bent Electro-Absorption Modulator

    DEFF Research Database (Denmark)

    2002-01-01

    The present invention relates to a method and a device for modulating optical signals based on modulating bending losses in bend, quantum well semiconductor waveguide sections. The complex refractive index of the optical active semiconducting components of the waveguide section is modulated...... components and the applied electric field in relation to the frequency of the modulated radiation, the bending losses (and possibly coupling losses) will provide extinction of light guided by the bent waveguide section. The refractive index contract may be modulated while keeping the absorption coefficient...... substantially constant and small, whereby the guided light can be modulated only by bending losses. Alternatively, the invention may be applied to enhance the extinction ratio of existing absorption modulators such as Electro-Absorption Modulators (EAMs) in which case extinction by absorption and extinction...

  10. Univariate Niho Bent Functions from o-Polynomials

    OpenAIRE

    Budaghyan, Lilya; Kholosha, Alexander; Carlet, Claude; Helleseth, Tor

    2014-01-01

    In this paper, we discover that any univariate Niho bent function is a sum of functions having the form of Leander-Kholosha bent functions with extra coefficients of the power terms. This allows immediately, knowing the terms of an o-polynomial, to obtain the powers of the additive terms in the polynomial representing corresponding bent function. However, the coefficients are calculated ambiguously. The explicit form is given for the bent functions obtained from quadratic and cubic o-polynomi...

  11. The ranks of Maiorana-McFarland bent functions

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this paper, the ranks of a special family of Maiorana-McFarland bent functions are discussed. The upper and lower bounds of the ranks are given and those bent functions whose ranks achieve these bounds are determined. As a consequence, the inequivalence of some bent functions are derived. Furthermore, the ranks of the functions of this family are calculated when t 6.

  12. The ranks of Maiorana-McFarland bent functions

    Institute of Scientific and Technical Information of China (English)

    WENG GuoBiao; FENG RongQuan; QIU WeiSheng; ZHENG ZhiMing

    2008-01-01

    In this paper,the ranks of a special family of Maiorana-McFarland bent functions are discussed.The upper and lower bounds of the ranks are given and those bent functions whose ranks achieve these bounds are determined.As a consequence,the inequivalence of some bent functions are derived.Furthermore,the ranks of the functions of this family are calculated when t≤6.

  13. Bent Solenoids with Superimposed Dipole Fields

    Energy Technology Data Exchange (ETDEWEB)

    Meinke, Rainer, B.; Goodzeit, Carl, L.

    2000-03-21

    A conceptual design and manufacturing technique were developed for a superconducting bent solenoid magnet with a superimposed dipole field that would be used as a dispersion device in the cooling channel of a future Muon Collider. The considered bent solenoid is equivalent to a 180° section of a toroid with a major radius of ~610 mm and a coil aperture of ~416 mm. The required field components of this magnet are 4 tesla for the solenoid field and 1 tesla for the superimposed dipole field. A magnet of this size and shape, operating at these field levels, has to sustain large Lorentz forces resulting in a maximum magnetic pressure of about 2,000 psi. A flexible round mini-cable with 37 strands of Cu-NbTi was selected as the superconductor. Detailed magnetic analysis showed that it is possible to obtain the required superimposed dipole field by tilting the winding planes of the solenoid by ~25°. A complete structural analysis of the coil support system and the helium containment vessel under thermal, pressure, and Lorentz force loads was carried out using 3D finite element models of the structures. The main technical issues were studied and solutions were worked out so that a highly reliable magnet of this type can be produced at an affordable cost.

  14. Systemic transthyretin amyloidosis in a patient with bent spine syndrome.

    Science.gov (United States)

    Rezania, Kourosh; Pytel, Peter; Smit, Laurel J; Mastrianni, James; Dina, Michelle A; Highsmith, W Edward; Dogan, Ahmet

    2013-06-01

    Wild-type and mutant transthyretin (TTR) are implicated in systemic amyloidosis (ATTR). Myopathy is a rare complication of ATTR amyloidosis, however no patient with bent spine syndrome secondary to ATTR amyloidosis has been reported so far. We present the first case of bent spine syndrome in a patient with wild-type ATTR amyloidosis who also had concomitant Alzheimer's disease.

  15. Niho Bent Functions and Subiaco/Adelaide Hyperovals

    OpenAIRE

    Helleseth, Tor; Kholosha, Alexander; Mesnager, Sihem

    2012-01-01

    In this paper, the relation between binomial Niho bent functions discovered by Dobbertin et al. and o-polynomials that give rise to the Subiaco and Adelaide classes of hyperovals is found. This allows to expand the class of bent functions that corresponds to Subiaco hyperovals, in the case when $m\\equiv 2 (\\bmod 4)$.

  16. Study and Design of Spiral Bent Waveguide Configuration

    Institute of Scientific and Technical Information of China (English)

    ZENG Wen-hong; LIAO Yun; SHI Shuang-jin; QIU Qi; LI Wei

    2007-01-01

    A new version of the scalar transverse electric(TE) wave equation in the bent waveguide is introduced.Then,TE polarized field in curved single-mode waveguides is analyzed by using the finite-difference beam propagation method(FD-BPM).The bending loss in bent waveguides is gotten for the optical fields obtained from BPM and comparisons are made among losses of the waveguides with various curvature radiuses,refractive index differences and cross sections.Based on the results,the design of spiral bent waveguide configuration is proposed as follows:refractive index difference being of 0.007,both width and thickness of waveguides being of 6 μm,the curvature radius in the spiral centre being of 4 mm,and the bending loss coefficient of the designed spiral bent waveguide being of 0.302 3 dB/cm.

  17. Channeling and radiation in periodically bent crystals

    CERN Document Server

    Korol, Andrey V; Greiner, Walter

    2014-01-01

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

  18. Proton extraction from the CERN SPS using bent silicon crystals

    Science.gov (United States)

    Elsener, K.; Fidecaro, G.; Gyr, M.; Herr, W.; Klem, J.; Mikkelsen, U.; Møller, S. P.; Uggerhøj, E.; Vuagnin, G.; Weisse, E.

    1996-10-01

    The extraction of high energy particles from a circular accelerator by means of channeling in bent crystals is an attractive alternative to classical extraction schemes, in particular for high energy proton colliders where a classical scheme becomes expensive and incompatible with normal operation. This paper reviews the ongoing extraction experiments at the CERN-SPS with bent silicon crystals. It describes the principles of beam extraction by means of a bent crystal and the different extraction schemes used: first- and multi-pass extraction and the methods to create diffusion. The limitations in tuning the accelerator to the desired impact parameters and crucial items concerning crystal preparation, bending and pre-alignment are discussed. The experimental procedures including an overview of the detection of circulating and extracted beam are given. Finally, the paper summarizes the results of these experiments together with ideas for future developments.

  19. Recent progress on the mechanics of sharply bent DNA

    Science.gov (United States)

    Cong, PeiWen; Yan, Jie

    2016-08-01

    Despite extensive studies on the mechanics of DNA under external constrains, such as tension, torsion, and bending, several important aspects have remained poorly understood. One biologically important example is the mechanics of DNA under sharp bending conditions, which has been debated for a decade without thorough comprehension. The debate is about the interesting phenomenon raised from a series of different experiments: sharply bent DNA has a surprisingly high apparent bending flexibility that deviates from the canonical bending elasticity of DNA. This finding has motivated various theoretical models, which mainly incorporate the excitation of mechanical defects inside severely bent DNA molecules. Here, we review the recent progress on the understanding of the mechanics of sharply bent DNA and provide our view on this important question by interrogating the theoretical foundation of these experimental measurements.

  20. Proofs of two conjectures on ternary weakly regular bent functions

    OpenAIRE

    Helleseth, Tor; Hollmann, Henk D. L.; Kholosha, Alexander; Wang, Zeying; Xiang, Qing

    2008-01-01

    We study ternary monomial functions of the form $f(x)=\\Tr_n(ax^d)$, where $x\\in \\Ff_{3^n}$ and $\\Tr_n: \\Ff_{3^n}\\to \\Ff_3$ is the absolute trace function. Using a lemma of Hou \\cite{hou}, Stickelberger's theorem on Gauss sums, and certain ternary weight inequalities, we show that certain ternary monomial functions arising from \\cite{hk1} are weakly regular bent, settling a conjecture of Helleseth and Kholosha \\cite{hk1}. We also prove that the Coulter-Matthews bent functions are weakly regular.

  1. Dispersion in a bent-solenoid channel with symmetric focusing

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-08-21

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

  2. Productivity and ergonomic investigation of bent-handle pliers.

    Science.gov (United States)

    Duke, Kelly; Mirka, Gary A; Sommerich, Carolyn M

    2004-01-01

    Awkward wrist posture is generally considered an occupational risk factor for hand/wrist disorders, leading to the ergonomic design principle of "bend the tool, not the wrist." Sixteen participants performed a computer jumper installation task and a simple assembly task while productivity, wrist posture, and shoulder posture were measured. The work surface orientation (vertical and 45 degrees) and the level of constraint placed on the user (constrained grip and unconstrained grip) were also varied. The results indicate that the beneficial effects of the bent-handle pliers are task dependent. In the computer jumper task the bent-handle pliers resulted in 5.3% faster task performance, whereas in the assembly task performance was 4.9% faster with the straight-handle pliers. The bent-handle pliers reduced shoulder deviations by 50% in the jumper installation task, and ulnar deviation was reduced by 12% and 22% for the jumper installation task and the assembly task, respectively (all significant at p ergonomic utility of bent-handle pliers can be considerable but that the 3-D kinematics characteristics of the task must be considered.

  3. Proton extraction from the SPS with a bent crystal

    Science.gov (United States)

    Ferroni, F.; Akbari, H.; Altuna, X.; Bardin, S.; Bellazzini, R.; Biryukov, V.; Brez, A.; Bussa, M. P.; Busso, L.; Calcaterra, A.; Carboni, G.; Costantini, F.; De Sangro, R.; Elsener, K.; Ferioli, G.; Ferrari, A.; Ferri, G. P.; Ferroni, F.; Fidecaro, G.; Freund, A.; Guinand, R.; Gyr, M.; Herr, W.; Hilaire, A.; Jensen, B. N.; Klem, J.; Lanceri, L.; Maier, K.; Massai, M. M.; Mertens, V.; Moller, S. P.; Morganti, S.; Palamara, O.; Peraire, S.; Petrera, S.; Placidi, M.; Santacesaria, R.; Scandale, W.; Schmidt, R.; Taratin, A. M.; Tosello, F.; Uggerhoj, E.; Vetterman, B.; Vita, P. E.; Vuagnin, G.; Weisse, E.; Weisz, S.; RD22 Collaboration

    1994-11-01

    The RD22 Collaboration has performed several measurements on the extraction of protons from the CERN-SPS by planar channeling in bent silicon monocrystals. Extraction efficiencies of about 10% have been routinely achieved for a bending angle of 8.5 mrad with the SPS running at 120 GeV.

  4. Counting all bent functions in dimension eight 99270589265934370305785861242880

    DEFF Research Database (Denmark)

    Langevin, Philippe; Leander, Gregor

    2011-01-01

    Based on the classification of the homogeneous Boolean functions of degree 4 in 8 variables we present the strategy that we used to count the number of all bent functions in dimension 8. There are $$99270589265934370305785861242880 \\approx 2^{106}$$such functions in total. Furthermore, we show...

  5. I/O correlation properties of bent functions

    Institute of Scientific and Technical Information of China (English)

    张宝东; 吕述望

    2000-01-01

    Let f( x1, x2, …, xn) be a Boolean bent function with n variables. The mutual information between the output variable and m linearly independent affine functions with respect to x1, x2, …, xn is studied. The results show that the mutual information depends mainly on m and n, but little on the structure of function f.

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

    Science.gov (United States)

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

    2011-07-01

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

  7. Genetic Analysis on Bent Characters of Cucumber Fruit

    Institute of Scientific and Technical Information of China (English)

    ZHANG Peng; QIN Zhiwei; WANG Lili; ZHOU Xiuyan

    2011-01-01

    Bent varieties and straight varieties were made as parents for the genetic analysis to investigate cucumber bending genetic mechanism. The results showed that the bent characters of the cucumber fruit (BCCF) were quantitative inheritance controlled by multiple genes and major genes. The additive effect played the main role and the dominance effect played the lesser role. Compared with the additive environmental variance, the dominant-environmental variance was more important and the cucumber fruit was more easily affected by the additive effect. The broad heritability and the narrow heritability of BCCF were both higher. The varieties of D0455 and D07299 could be used as parents which were benefit for improving the straight characters of the cucumber fruit

  8. Revisit the anomalous bending elasticity of sharply bent DNA

    CERN Document Server

    Cong, Peiwen; Chen, Hu; van der Maarel, Johan R C; Doyle, Patrick S; Yan, Jie

    2015-01-01

    Several recent experiments have suggested that sharply bent DNA has a surprisingly high bending flexibility, but the cause is poorly understood. It has been demonstrated that excitation of flexible defects can explain the results; while whether such defects can be excited under the level of DNA bending in those experiments has remained unclear and been debated. Interestingly, due to experimental design DNA contained pre-existing nicks in nearly all those experiments, while the potential effect of nicks have never been considered. Here, using full-atom molecular dynamics (MD) simulations, we show that nicks promote DNA basepair disruption at the nicked sites which drastically reduced DNA bending energy. In the absence of nicks, basepair disruption can also occur, but it requires a higher level of DNA bending. Overall, our results challenge the interpretations of previous sharp DNA bending experiments and highlight that the micromechanics of sharply bent DNA still remains an open question.

  9. Vertical neutron beam focusing with bent mosaic crystals

    Science.gov (United States)

    Courtois, P.

    2016-09-01

    We report on the performance of bent mosaic crystals when used as a vertical focusing neutron monochromator. High-quality Cu(200) and Ge(335) mosaic crystals with a controlled curvature have been successfully produced at the ILL using plastic deformation at high temperature. As expected from simple geometrical considerations, they exhibit excellent properties for focusing a neutron beam vertically when examined on a high-resolution diffractometer installed on an m = 1 thermal neutron guide. Both Cu(200) and Ge(335) curved crystals allow a significant reduction of the focal image size at the sample position compared with a flat crystal with the same defect concentration. As a result, significant gain factors of 6 to 7 in intensity were obtained by replacing a flat crystal of 30 mm with a bent crystal.

  10. Measurement of the intermodal crosstalk of a bent multimode waveguide.

    Science.gov (United States)

    Wang, Jian; Zhao, Changyun; Wei, Bing; Gencheng, Wang; Dai, Tingge; Wang, Yuehai; Jiang, Xiaoqing; Li, Yubo; Yang, Jianyi

    2016-09-20

    We quantitatively investigate the main source of the intermodal crosstalk of a silicon-based bent multimode waveguide by experiment. The measurement is performed through time-domain scanning low-coherence interferometry. From the measurement results, one can not only calculate the modal crosstalk, but can also locate the position where the crosstalk appears. The results indicate that the modal mismatch at the points where the curvature of the waveguide changes is the main origin of the modal crosstalk. For a two-mode waveguide with a bending radius of 5 μm at 1310 nm, the crosstalk is as high as -20 and -16  dB for the fundamental and first-order mode, respectively. This work gives us a deep insight into how the guided modes actually propagate through the bent waveguide.

  11. Simulations of electron channeling in bent silicon crystal

    CERN Document Server

    Sushko, G B; Korol, A V; Greiner, Walter; Solov'yov, A V; Polozkov, R G; Ivanov, V K

    2013-01-01

    We report on the results of theoretical simulations of the electron channeling in a bent silicon crystal. The dynamics of ultra-relativistic electrons in the crystal is computed using the newly developed part [1] of the MBN Explorer package [2,3], which simulates classical trajectories of in a crystalline medium by integrating the relativistic equations of motion with account for the interaction between the projectile and crystal atoms. A Monte Carlo approach is employed to sample the incoming electrons and to account for thermal vibrations of the crystal atoms. The electron channeling along Si(110) crystallographic planes are studied for the projectile energies 195--855 MeV and different curvatures of the bent crystal.

  12. Bent Dinuclear Platinum(II Halo-Bridged Carbonyl Complexes

    Directory of Open Access Journals (Sweden)

    Fabio Marchetti

    2011-07-01

    Full Text Available Crystals of trans-Pt2(μ-X2X2(CO2 (X = Br, I have been grown and their molecular and crystalline structures have been solved by X-ray diffraction methods. In both cases the dinuclear molecules are bent, with a bending angle of 164.6° and 156.5° for the bromide and the iodide, respectively. While the structure of the bromo-derivative is reported here for the first time, a modification of trans-Pt2(μ-I2I2(CO2 with planar centrosymmetric molecules is known. This appears to be a rare case of a platinum(II halo-bridged derivative structurally characterized in both bent and planar forms.

  13. Volume reflection efficiency for negative particles in bent crystals

    Science.gov (United States)

    Biryukov, V. M.

    2017-02-01

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

  14. Volume reflection efficiency for negative particles in bent crystals

    Directory of Open Access Journals (Sweden)

    V.M. Biryukov

    2017-02-01

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

  15. Ram pressure statistics for bent tail radio galaxies

    CERN Document Server

    Mguda, Zolile; van der Heyden, Kurt; Gottlöber, Stefan; Cress, Catherine; Vaisanen, Petri; Yepes, Gustavo

    2014-01-01

    In this paper we use the MareNostrum Universe Simulation, a large scale, hydrodynamic, non-radiative simulation in combination with a simple abundance matching approach to determine the ram pressure statistics for bent radio sources (BRSs). The abundance matching approach allows us to determine the locations of all galaxies with stellar masses $> 10^{11} MSol$ in the simulation volume. Assuming ram pressure exceeding a critical value causes bent morphology, we compute the ratio of all galaxies exceeding the ram pressure limit (RPEX galaxies) relative to all galaxies in our sample. According to our model 50% of the RPEX galaxies at $z = 0$ are found in clusters with masses larger than $10^{14.5}MSol$ the other half resides in lower mass clusters. Therefore, the appearance of bent tail morphology alone does not put tight constraints on the host cluster mass. In low mass clusters, $M 10^{15}Msol$ they can be found at distances up to 1.5Mpc. Only clusters with masses $> 10^{15}MSol $ are likely to host more than...

  16. Synthesis and mesomorphic properties of bent-shaped molecule with low bent-angle central core and long alkylthio tail

    Institute of Scientific and Technical Information of China (English)

    Xiao Dong Li; Mao Sheng Zhan; Kai Wang

    2011-01-01

    Two homologous series of bent-shaped molecules composed of low bent-angle naphthalene central core and long alkoxy tail or alkylthio tail, N(1,7)-n-OPIMB and W(1,7)-n-SPIMB (n = 20, 22), respectively, were synthesized. The mesomorphic properties were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (XRD). Compared to the direct transition from the isotropic phase to the chiral B4 phase examined in N(1,7)-n-OPIMB, N(1,7)-n-SPIMB exhibited a rare Iso-Ncol-Colh-B4 phase sequence. The combination of the asymmetric low bent-angle 1,7-naphathalene central core and the flexible long alkylthio tail is considered to play an important role in the formation of such a novel phase sequence. (c) 2011 Mao Sheng Zhan. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

  17. Bent Branderup - akadeemilise ratsutamiskunsti rüütel / Eda Vallimäe

    Index Scriptorium Estoniae

    Vallimäe, Eda

    2014-01-01

    Taani ratusutamismeister Bent Branderup on ellu äratanud ajaloo- ja kultuuripärandit esindava akadeemilise ratsutamiskunsti, mis kombineerib parimad teadmised vanadelt ratsutamismeistritelt moodsa hobumaailmaga

  18. Quantum effects for particles channeling in a bent crystal

    Science.gov (United States)

    Feranchuk, Ilya; San, Nguyen Quang

    2016-09-01

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

  19. Analysis of Circular Polarization of Cylindrically Bent Microstrip Antennas

    Directory of Open Access Journals (Sweden)

    Tiiti Kellomäki

    2012-01-01

    Full Text Available When circularly polarized (CP microstrip antennas are bent, the polarization becomes elliptical. We present a simple model that describes the phenomenon. The two linear modes present in a CP patch are modeled separately and added together to produce CP. Bending distorts the almost-spherical equiphase surface of a linearly polarized patch, which leads to phase imbalance in the far-field of a CP patch. The model predicts both the frequency shifting of the axial ratio band as well as the narrowing of the axial ratio beam. Uncontrolled bending is a problem associated especially with flexible textile antennas, and wearable antennas should therefore be designed somewhat conformal.

  20. Riot at the calc exam and other mathematically bent stories

    CERN Document Server

    Adams, Colin

    2009-01-01

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

  1. Direct numerical simulation of turbulence in a bent pipe

    Science.gov (United States)

    Schlatter, Philipp; Noorani, Azad

    2013-11-01

    A series of direct numerical simulations of turbulent flow in a bent pipe is presented. The setup employs periodic (cyclic) boundary conditions in the axial direction, leading to a nominally infinitely long pipe. The discretisation is based on the high-order spectral element method, using the code Nek5000. Four different curvatures, defined as the ratio between pipe radius and coil radius, are considered: κ = 0 (straight), 0.01 (mild curvature), 0.1 and 0.3 (strong curvature), at bulk Reynolds numbers of up to 11700 (corresponding to Reτ = 360 in the straight pipe case). The result show the turbulence-reducing effect of the curvature (similar to rotation), leading close to relaminarisation in the inner side; the outer side, however, remains fully turbulent. Prpoer orthogonal decomposition (POD) is used to extract the dominant modes, in an effort to explain low-frequency switching of sides inside the pipe. A number of additional interesting features are explored, which include sub-straight and sub-laminar drag for specific choices of curvature and Reynolds number: In particular the case with sub-laminar drag is investigated further, and our analysis shows the existence of a spanwise wave in the bent pipe, which in fact leads to lower overall pressure drop.

  2. Planar channeling and quasichanneling oscillations in a bent crystal

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-02-15

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

  3. 31 CFR 100.11 - Exchange of bent and partial coins.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Exchange of bent and partial coins. 100.11 Section 100.11 Money and Finance: Treasury Regulations Relating to Money and Finance EXCHANGE OF PAPER CURRENCY AND COIN Exchange of Coin § 100.11 Exchange of bent and partial coins....

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

    Directory of Open Access Journals (Sweden)

    A. V. Sokolov

    2016-01-01

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

  5. Development of Exterior Anti-corrosion Coating Production Line for Large Diameter Hot Bent Pipes

    Institute of Scientific and Technical Information of China (English)

    JiaoRuyi; ZhangYing

    2004-01-01

    The epoxy powder exterior anti-corrosion coating production line for bent pipes with a single (double) course production is a technologically advanced bent pipe anti-corrosion method with cost efficiency, environment friendliness and stable coating quality. The quality of the coating on the bent pipe fully meets the requirements of the current national and industrial standards. The application of the technology has filled the gap in the bent pipe anti-corrosion coating area of China, and leads the world technologically. With this technology the coating quality of the bent pipe has greatly improved, resulting in significant social and economic benefits. With the use of the technology in various large scale pipeline projects such as the “West to East Gas Pipeline Project”, it will exhibite a greater potential in the future pipeline projects with a broad application prospect.

  6. Gamma-ray streaming in bent ducts and voids

    Energy Technology Data Exchange (ETDEWEB)

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

    1983-05-01

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

  7. Channeling of ultra-relativistic positrons in bent diamond crystals

    Directory of Open Access Journals (Sweden)

    R.G. Polozkov

    2015-06-01

    Full Text Available Results of numerical simulations of channeling of ultra-relativistic positrons are reported for straight and uniformly bent diamond crystals. The projectile trajectories in a crystal are computed using a newly developed module of the MBN Explorer package which simulates classical trajectories in a crystalline medium by integrating the relativistic equations of motion with account for the interaction between the projectile and the crystal atoms. The Monte Carlo method is employed to sample the incoming positrons and to account for thermal vibrations of the crystal atoms. The channeling parameters and emission spectra of incident positrons with a projecti le energy of 855 MeV along C(110 crystallographic planes are calculated for different bending radii of the crystal. Two features of the emission spectrum associated with positron oscillations in a channel and synchrotron radiation are studied as a function of crystal curvature.

  8. Levelized Cost of Energy for a Backward Bent Duct Buoy

    Energy Technology Data Exchange (ETDEWEB)

    Bull, Diana; Jenne, D. Scott; Smith, Christopher S.; Copping, Andrea E.; Copeland, Guild

    2016-12-01

    The Reference Model Project, supported by the U.S. Department of Energy, was developed to provide publically available technical and economic benchmarks for a variety of marine energy converters. The methodology to achieve these benchmarks is to develop public domain designs that incorporate power performance estimates, structural models, anchor and mooring designs, power conversion chain designs, and estimates of the operations and maintenance, installation, and environmental permitting required. The reference model designs are intended to be conservative, robust, and experimentally verified. The Backward Bent Duct Buoy (BBDB) presented in this paper is one of three wave energy conversion devices studied within the Reference Model Project. Comprehensive modeling of the BBDB in a Northern California climate has enabled a full levelized cost of energy (LCOE) analysis to be completed on this device.

  9. Simulation of a Laue lens with bent Ge(111) crystals

    CERN Document Server

    Valsan, Vineeth; Frontera, Filippo; Liccardo, Vincenzo; Caroli, Ezio; Stephen, John B

    2015-01-01

    In the context of Laue project for focusing hard X-/ soft gamma-rays, an entire Laue lens, using bent Ge(111) crystal tiles, with 40 meters curvature radius, is simulated with a focal length of 20 meters. The focusing energy band is between 80 keV and 600 keV. The distortion of the output image of the lens on the focal plane due to the effect of crystal tile misalignment as well as the radial distortion arising from the curvature of the crystal is discussed in detail. Expected detection efficiency and instrument background is also estimated. Finally the sensitivity of the Laue lens is calculated. A quantitative analysis of the results of these simulation is also presented.

  10. Reversible greyscale memory effect of a bent-core liquid crystal

    Energy Technology Data Exchange (ETDEWEB)

    Hong Zhe; Jin Yan [Department of Display Engineering, Hoseo University, Asan, Chungnam 336-795 (Korea, Republic of); Lee, Ji-Hoon; Yoon, Tae-Hoon [School of Electrical Engineering, Pusan National University, Busan 609-735 (Korea, Republic of); Choi, E-Joon; Lee, Eun-Woo, E-mail: jihoonlee@pusan.ac.kr, E-mail: ejchoi@kumoh.ac.kr [Department of Polymer Science and Engineering, Kumoh National Institute of Technology, Gumi, Gyungbuk 730-701 (Korea, Republic of)

    2011-10-19

    Memory effect of a bent-core liquid crystal (LC) in smectic A phase was studied. The bent-core LC formed spatially distributed domains with different threshold fields, and the domains showed a bistable switching from a planar to a homeotropic state under an electric field across the cell. The fraction of homeotropic domains was gradually increased with stronger electric field, thus an analogue greyscale memory effect was obtained by the relative fraction between the planar and homeotropic domains. The bent-core molecules could be reversibly switched back to the initial planar state by applying an in-plane electric field.

  11. Dynamical focusing by bent, asymmetrically cut perfect crystals in Laue geometry.

    Science.gov (United States)

    Guigay, J P; Ferrero, C

    2016-07-01

    A semi-analytical approach based on the influence functions of a point source located on the crystal surface has been adopted to show that the focusing ability of cylindrically bent Laue crystals may be strongly enhanced by replacing symmetrically cut crystals with asymmetrically cut crystals. This approach is generally applicable to any distance between the X-ray source and the focusing bent crystal. A mathematically straightforward method to simplify the derivation of the already known expression of the influence functions in the case of deformed crystals with a constant strain gradient (e.g. cylindrically bent crystals) is also presented.

  12. Analytic Matrix Method for the Study of Propagation Characteristics of a Bent Planar Waveguide

    Institute of Scientific and Technical Information of China (English)

    LIU Qing; CAO Zhuang-Qi; SHEN Qi-Shun; DOU Xiao-Ming; CHEN Ying-Li

    2000-01-01

    An analytic matrix method is used to analyze and accurately calculate the propagation constant and bendinglosses of a bent planar waveguide. This method gives not only a dispersion equation with explicit physical insight,but also accurate complex propagation constants.

  13. Elliptically Bent X-ray Mirrors with Active Temperature Stabilization

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Sheng; Church, Matthew; Yashchuk, Valeriy V.; Goldberg, Kenneth A.; Celestre, Rich; McKinney, Wayne R.; Kirschman, Jonathan; Morrison, Greg; Noll, Tino; Warwick, Tony; Padmore, Howard A.

    2010-01-31

    We present details of design of elliptically bent Kirkpatrick-Baez mirrors developed and successfully used at the Advanced Light Source for submicron focusing. A distinctive feature of the mirror design is an active temperature stabilization based on a Peltier element attached directly to the mirror body. The design and materials have been carefully optimized to provide high heat conductance between the mirror body and substrate. We describe the experimental procedures used when assembling and precisely shaping the mirrors, with special attention paid to laboratory testing of the mirror-temperature stabilization. For this purpose, the temperature dependence of the surface slope profile of a specially fabricated test mirror placed inside a temperature-controlled container was measured. We demonstrate that with active mirror-temperature stabilization, a change of the surrounding temperature by more than 3K does not noticeably affect the mirror figure. Without temperature stabilization, the surface slope changes by approximately 1.5 ?mu rad rms (primarily defocus) under the same conditions.

  14. On the energy dependence of proton beam extraction with a bent crystal

    CERN Document Server

    Arduini, Gianluigi; Fidecaro, Giuseppe; Gyr, Marcel; Herr, Werner; Klem, J T; Mikkelsen, U; Weisse, E

    1998-01-01

    Proton beam extraction from the CERN SPS by means of a bent silicon crystal is reported at three different energies, 14 GeV, 120 GeV and 270 GeV. The experimental results are compared to computer simulations which contain a sound model of the SPS accelerator as well as the channeling phenomena in bent crystals. The overall energy dependence of crystal assisted proton beam extraction is understood and provides the basis to discuss such a scheme for future accelerators.

  15. Oblique detonation waves stabilized in rectangular-cross-section bent tubes

    OpenAIRE

    2011-01-01

    Oblique detonation waves, which are generated by a fundamental detonation phenomenon occurring in bent tubes, may be applied to fuel combustion in high-efficiency engines such as a pulse detonation engine (PDE) and a rotating detonation engine (RDE). The present study has experimentally demonstrated that steady-state oblique detonation waves propagated stably through rectangular-cross-section bent tubes by visualizing these waves using a high-speed camera and the shadowgraph method. The obliq...

  16. A new class of hyper-bent Boolean functions in binomial forms

    CERN Document Server

    Wang, Baocheng; Qi, Yanfeng; Yang, Yixian; Xu, Maozhi

    2011-01-01

    Bent functions, which are maximally nonlinear Boolean functions with even numbers of variables and whose Hamming distance to the set of all affine functions equals $2^{n-1}\\pm 2^{\\frac{n}{2}-1}$, were introduced by Rothaus in 1976 when he considered problems in combinatorics. Bent functions have been extensively studied due to their applications in cryptography, such as S-box, block cipher and stream cipher. Further, they have been applied to coding theory, spread spectrum and combinatorial design. Hyper-bent functions, as a special class of bent functions, were introduced by Youssef and Gong in 2001, which have stronger properties and rarer elements. Many research focus on the construction of bent and hyper-bent functions. In this paper, we consider functions defined over $\\mathbb{F}_{2^n}$ by $f_{a,b}:=\\mathrm{Tr}_{1}^{n}(ax^{(2^m-1)})+\\mathrm{Tr}_{1}^{4}(bx^{\\frac{2^n-1}{5}})$, where $n=2m$, $m\\equiv 2\\pmod 4$, $a\\in \\mathbb{F}_{2^m}$ and $b\\in\\mathbb{F}_{16}$. When $a\\in \\mathbb{F}_{2^m}$ and $(b+1)(b^4+b...

  17. Clinical and radiographic delineation of Bent Bone Dysplasia-FGFR2 type or Bent Bone Dysplasia with Distinctive Clavicles and Angel-shaped Phalanges.

    Science.gov (United States)

    Krakow, Deborah; Cohn, Daniel H; Wilcox, William R; Noh, Grace J; Raffel, Leslie J; Sarukhanov, Anna; Ivanova, Margarita H; Danielpour, Moise; Grange, Dorothy K; Elliott, Alison M; Bernstein, Jonathan A; Rimoin, David L; Merrill, Amy E; Lachman, Ralph S

    2016-10-01

    Bent Bone Dysplasia-FGFR2 type is a relatively recently described bent bone phenotype with diagnostic clinical, radiographic, and molecular characteristics. Here we report on 11 individuals, including the original four patients plus seven new individuals with three longer-term survivors. The prenatal phenotype included stillbirth, bending of the femora, and a high incidence of polyhydramnios, prematurity, and perinatal death in three of 11 patients in the series. The survivors presented with characteristic radiographic findings that were observed among those with lethality, including bent bones, distinctive (moustache-shaped) small clavicles, angel-shaped metacarpals and phalanges, poor mineralization of the calvarium, and craniosynostosis. Craniofacial abnormalities, hirsutism, hepatic abnormalities, and genitourinary abnormalities were noted as well. Longer-term survivors all needed ventilator support. Heterozygosity for mutations in the gene that encodes Fibroblast Growth Factor Receptor 2 (FGFR2) was identified in the nine individuals with available DNA. Description of these patients expands the prenatal and postnatal findings of Bent Bone Dysplasia-FGFR2 type and adds to the phenotypic spectrum among all FGFR2 disorders. © 2016 Wiley Periodicals, Inc.

  18. The elusive thermotropic biaxial nematic phase in rigid bent-core molecules

    Indian Academy of Sciences (India)

    Bharat R Acharya; Andrew Primak; Theo J Dingemans; Edward T Samulski; Satyendra Kumar

    2003-08-01

    The biaxial nematic liquid crystalline phase was predicted several decades ago. Several vigorous attempts to find it in various systems resulted in mis-identifications. The results of X-ray diffraction and optical texture studies of the phases exhibited by rigid bent-core molecules derived from 2,5-bis-(-hydroxyphenyl)-1,3,4-oxadiazole reveal that the biaxial nematic phase is formed by three compounds of this type. X-ray diffraction studies reveal that the nematic phase of these compounds has the achiral symmetry D2h, in which the overall long axes of the molecules are oriented parallel to each other to define the major axis of the biaxial phase. The apex of the bent-cores defines the minor axis of this phase along which the planes containing the bent-cores of neighboring molecules are oriented parallel to each other.

  19. Channeling of high-energy particles in bent crystals - Experiments at the CERN SPS

    Science.gov (United States)

    Baurichter, A.; Biino, C.; Clément, M.; Doble, N.; Elsener, K.; Fidecaro, G.; Freund, A.; Gatignon, L.; Grafström, P.; Gyr, M.; Hage-Ali, M.; Herr, W.; Keppler, P.; Kirsebom, K.; Klem, J.; Major, J.; Medenwaldt, R.; Mikkelsen, U.; Møller, S. P.; Siffert, P.; Uggerhøj, E.; Vilakazi, Z. Z.; Weisse, E.

    2000-04-01

    During the latest decade, experiments have been performed at the CERN SPS to investigate the use of high-energy channeled nuclei in bent crystals for extraction, beam splitting and beam bending. An understanding of channeling in a bent crystal with extraction and deflection efficiencies for different energies, crystal types and ions has been developed. Furthermore, the long-standing question of radiation damage has been addressed with encouraging outcome. This makes extrapolations possible for the construction of, e.g., an extraction device for the LHC at CERN, RHIC at Brookhaven or new splitting elements in high-energy beams.We present the main results obtained and discuss existing and future applications of bent crystals in high-energy physics.

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

    Science.gov (United States)

    Loisel, G. P.; Wu, M.; Stolte, W.; Kruschwitz, C.; Lake, P.; Dunham, G. S.; Bailey, J. E.; Rochau, G. A.

    2016-11-01

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

  1. From antiferroelectricity to ferroelectricity in smectic mesophases formed by bent-core molecules

    Indian Academy of Sciences (India)

    Carsten Tschierske; Gert Dantlgraber

    2003-08-01

    This contribution gives an overview of ferroelectric switching liquid crystalline phases formed by bent-core molecules. First a description of some general principles behind the mesophase formation within bent-core systems will be given, followed by a short review of the mesophase structures formed by such molecules. Then, different classes of ferroelectric switching bent-core mesogens will be described. This type of switching behaviour has been reported for several subtypes of polar smectic phases (B2, B5, B7 and SmCG) and recently for columnar mesophases. In this discussion particular attention will be made to polyphilic bent-core molecules, composed of three incompatible units, a bent aromatic core, alkyl chains and an oligosiloxane unit. The importance of the decoupling of the layers into microsegregated sublayers for the ferroelectric organisation is discussed. Many of the ferroelectric switching mesophases show dark textures with distinct regions of opposite chirality in their ground states. It is discussed that this might be due to a helical superstructure formed as a result of an escape from macroscopic polar order. Hence, the materials themselves are not ferroelectric in the ground state, but upon alignment within an electric field in the measuring cells the ferroelectric states are stabilised by surface interactions, leading to a ferroelectric switching system. The designing principle was extended to mesogenic dimers with bent-core structural units. For these compounds, depending on the number of dimethylsiloxane units in the spacer either ferroelectric or antiferroelectric switching was observed, whereby the effect of parity is reversed to that observed for conventional calamitic dimesogens. Finally, a carbosilane-based first generation dendrimer is reported. It shows a ferroelectric switching phase, for which a non-correlated organisation of tilted polar smectic layers is proposed (SmCPR).

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

    Science.gov (United States)

    Scandale, W.; Kovalenko, A. D.; Taratin, A. M.

    2017-03-01

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

  3. Energy funneling in a bent chain of Morse oscillators with long-range coupling

    DEFF Research Database (Denmark)

    Larsen, Peter Ulrik Vingaard; Christiansen, Peter Leth; Bang, Ole;

    2004-01-01

    A bent chain of coupled Morse oscillators with long-range dispersive interaction is considered. Moving localized excitations may be trapped in the bending region. Thus chain geometry acts like an impurity. An energy funneling effect is observed in the case of random initial conditions.......A bent chain of coupled Morse oscillators with long-range dispersive interaction is considered. Moving localized excitations may be trapped in the bending region. Thus chain geometry acts like an impurity. An energy funneling effect is observed in the case of random initial conditions....

  4. High efficiency multi-pass proton beam extraction with a bent crystal at the SPS

    Science.gov (United States)

    Altuna, X.; Bussa, M. P.; Carboni, G.; Dehning, B.; Elsener, K.; Ferrari, A.; Fidecaro, G.; Freund, A.; Guinand, R.; Gyr, M.; Herr, W.; Klem, J.; Laffin, M.; Lanceri, L.; Mikkelsen, U.; Møller, S. P.; Scandale, W.; Tosello, F.; Uggerhøj, E.; Vuagnin, G.; Weisse, E.; Weisz, S.

    1995-02-01

    Recent measurements of 120 GeV proton extraction by means of a bent silicon crystal at the CERN-SPS accelerator are summarized. The existence of multi-pass extraction has been proven by blocking first-pass extraction: using a crystal covered with an amorphous layer, extracted beam with high efficiency was observed, which provides a direct proof for the importance of the multi-pass mechanism. This opens new possibilities in the design and optimization of a bent crystal extraction scheme.

  5. Deflection of 450 GeV protons by planar channeling in a bent silicon crystal

    Science.gov (United States)

    Jensen, B. N.; Møller, S. P.; Uggerhøj, E.; Worm, T.; Atherton, H. W.; Clément, M.; Doble, N.; Elsener, K.; Gatignon, L.; Grafström, P.; Jeanneret, J. B.; Hage-Ali, M.; Siffert, P.

    1992-08-01

    A 450 GeV proton beam has been bent by various angles from 4 to 14 mrad using planar channeling in a (111) silicon crystal. Detailed investigations of the deflected beam as well as the unbent and scattered particles have been performed. The incident beam had a divergence of about 35 μrad (FWHM). 20% of the protons hitting the crystal front face were found to be initially channeled. The measured bending efficiencies range from 5 to 2% (for increasing deflection angles) are compared to theoretical estimates including surface acceptance and dechanneling in bent silicon crystals.

  6. On the energy dependence of proton beam extraction with a bent crystal

    Science.gov (United States)

    Arduini, G.; Elsener, K.; Fidecaro, G.; Gyr, M.; Herr, W.; Klem, J.; Mikkelsen, U.; Weisse, E.

    1998-03-01

    Proton beam extraction from the CERN SPS by means of a bent silicon crystal is reported at three different energies, 14 GeV, 120 GeV and 270 GeV. The experimental results are compared to computer simulations which contain a sound model of the SPS accelerator as well as the channeling phenomena in bent crystals. The overall energy dependence of crystal assisted proton beam extraction is understood and provides the basis to discuss such a scheme for future accelerators. © 1998

  7. Deflection of 450 GeV protons by planar channeling in a bent silicon crystal

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, B.N.; Moeller, S.P.; Uggerhoej, E.; Worm, T. (Inst. for Synchrotron Radiation, Aarhus Univ. (Denmark)); Atherton, H.W.; Clement, M.; Doble, N.; Elsener, K.; Gatignon, L.; Grafstroem, P.; Jeanneret, J.B. (European Organization for Nuclear Research (CERN), Geneva (Switzerland)); Hage-Ali, M.; Siffert, P. (Centre de Recherches Nucleaires, 67 - Strasbourg (France))

    1992-08-01

    A 450 GeV proton beam has been bent by various angles from 4 to 14 mrad using planar channeling in a (111) silicon crystal. Detailed investigations of the deflected beam as well as the unbent and scattered particles have been performed. The incident beam had a divergence of about 35 [mu]rad (FWHM). 20% of the protons hitting the crystal front face were found to be initially channeled. The measured bending efficiencies range from 5 to 2% (for increasing deflection angles) and are compared to theoretical estimates including surface acceptance and dechanneling in bent silicon crystals. (orig.).

  8. Dual Symmetry in Bent-Core Liquid Crystals and Unconventional Superconductors

    Directory of Open Access Journals (Sweden)

    Vladimir Lorman

    2010-01-01

    Full Text Available We extend the Landau theory of bent-core mesophases and d-wave high-Tc superconductors by considering additional secondary pseudo-proper order parameters. These systems exhibit a remarkable analogy relating their symmetry groups, lists of phases, and an infinite set of physical tensors. This analogy lies upon an internal dual structure shared by the two theories. We study the dual operator transforming rotations into translations in liquid crystals, and gauge symmetries into rotations in superconductors. It is used to classify the bent-core line defects, and to analyze the electronic gap structure of lamellar d-wave superfluids.

  9. Microbiota bacteriana asociada a los cultivos de dos especies de diatomeas bentónicas.

    OpenAIRE

    Hernández-Zulueta, Joicye; Leal, Sylvia; Loza, Sandra

    2014-01-01

    Las diatomeas bentónicas forman biopelículas debido a las sustancias que secretan, que les permite mantenerse adheridas al sustrato. A ellas se asocian bacterias que, dada las condiciones no axénicas de los cultivos, pueden alterar su valor nutricional. El objetivo del presente trabajo fue caracterizar la microbiota bacteriana asociada a los cultivos de las microalgas bentónicas Navicula germanopolonica y Amphora sp., especies utilizadas para la precría del camarón en cultivo. Se aislaron e i...

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

    Science.gov (United States)

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

    1977-01-01

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

  11. Parallel code NSBC: Simulations of relativistic nuclei scattering by a bent crystal

    Science.gov (United States)

    Babaev, A. A.

    2014-01-01

    The presented program was designed to simulate the passage of relativistic nuclei through a bent crystal. Namely, the input data is related to a nuclei beam. The nuclei move into the crystal under planar channeling and quasichanneling conditions. The program realizes the numerical algorithm to evaluate the trajectory of nucleus in the bent crystal. The program output is formed by the projectile motion data including the angular distribution of nuclei behind the crystal. The program could be useful to simulate the particle tracking at the accelerator facilities used the crystal collimation systems. The code has been written on C++ and designed for the multiprocessor systems (clusters).

  12. What did we learn from the extraction experiments with bent crystals at the CERN SPS?

    CERN Document Server

    Elsener, K; Gyr, Marcel; Herr, Werner; Klem, J T; Mikkelsen, U; Weisse, E

    1998-01-01

    The feasibility and properties of particle extraction from an accelerator by means of a bent crystal were studied extensively at the CERN SPS. The main results of the experiments are presented. This includes the evidence for multipass extraction of heavy ions. These results are compared with theoretical expectations and computer simulations.

  13. Channeling, volume reflection, and volume capture study of electrons in a bent silicon crystal

    DEFF Research Database (Denmark)

    Wistisen, T. N.; Uggerhoj, U. I.; Wienands, U.;

    2016-01-01

    We present the experimental data and analysis of experiments conducted at SLAC National Accelerator Laboratory investigating the processes of channeling, volume-reflection and volume-capture along the (111) plane in a strongly bent quasimosaic silicon crystal. These phenomena were investigated at...

  14. Laterally substituted symmetric and nonsymmetric salicylideneimine-based bent-core mesogens

    Directory of Open Access Journals (Sweden)

    Sonja Findeisen-Tandel

    2012-01-01

    Full Text Available Bent-core mesogens have gained considerable importance due to their ability to form new mesophases with unusual properties. Relationships between the chemical structure of bent-core molecules and the type and physical properties of the formed mesophases are relatively unknown in detail and differ strongly from those known for calamitic liquid crystals. In this paper symmetric and nonsymmetric five-ring salicylideneaniline-based bent-core mesogens are presented, and the effect of lateral substituents attached at the outer phenyl rings (F, Cl, Br or the central phenyl ring (CH3 on the liquid-crystalline behaviour and on the physical properties is studied. Corresponding benzylideneaniline-based compounds were additionally prepared in order to study the influence of the intramolecular hydrogen bond. The occurring mesophases were investigated by differential scanning calorimetry, polarising microscopy, X-ray diffraction and dielectric and electro-optical measurements. The paper reports on new findings with respect to the structure–property relationships of bent-core mesogens. On one hand, the disruptive effect of laterally substituted halogen atoms, F, Cl and Br, on the mesophase behaviour of three isomeric series was much lower than expected. On the other hand, an increase of the clearing temperature by 34 K was observed, caused by small lateral substituents. The electro-optical behaviour, especially the type of polar switching and corresponding molecular movements, is sensitive to variations in the molecular structure.

  15. Note on the glide of a bird with wings bent downwards

    NARCIS (Netherlands)

    Sparenberg, J. A.

    2006-01-01

    This note considers the influence of the bending down of the wings of a bird on the performance of its glide. The induced drag of bent wings is compared with the induced drag of a corresponding straight wing. Numerical results are given.

  16. The theory of the centrifugal mechanism of feeding-in in bent crystals

    OpenAIRE

    2001-01-01

    For a particle channeled in the bent crystal planes (axes), the phenomenon of "bending dechanneling", which is a particle transition to a random state due to centrifugal force, is well known. We consider an analytical theory of the reverse phenomenon, i.e., feeding from a random state to a channeled state due to centrifugal force in a crystal with variable curvature.

  17. Two-dimensional refractive index and stresses profiles of a homogenous bent optical fiber.

    Science.gov (United States)

    Ramadan, W A; Wahba, H H; Shams El-Din, M A

    2014-11-01

    We present a significant contribution to the theory of determining the refractive index profile of a bent homogenous optical fiber. In this theory we consider two different processes controlling the index profile variations. The first is the linear index variation due to stress along the bent radius, and the second is the release of this stress on the fiber surface. This release process is considered to have radial dependence on the fiber radius. These considerations enable us to construct the index profile in two dimensions normal to the optical axis, considering the refraction of light rays traversing the fiber. This theory is applied to optical homogenous bent fiber with two bending radii when they are located orthogonal to the light path of the object arm in the holographic setup (like the Mach-Zehnder interferometer). Digital holographic phase shifting interferometry is employed in this study. The recorded phase shifted holograms have been combined, reconstructed, and processed to extract the phase map of the bent optical fiber. A comparison between the extracted optical phase differences and the calculated one indicates that the refractive index profile variation should include the above mentioned two processes, which are considered as a response for stress distribution across the fiber's cross section. The experimentally obtained refractive index profiles provide the stress induced birefringence profile. Thus we are able to present a realistic induced stress profile due to bending.

  18. Observation of Proton Reflection on Bent Silicon Crystals at the CERN SPS

    CERN Document Server

    Scandale, Walter

    2007-01-01

    We report the observation of the so-called volume reflection effect with 400 GeV/c protons interacting with bent silicon crystals in the H8 beam line performed by the H8RDD22 Collaboration at the CERN SPS. The volume reflection is an effect of the same nature of the particle channeling among the crystalline planes of a bent crystal. The reflection occurs at the tangency point of a particle trajectory with the bent crystalline planes where the transverse component of the particle momentum is reversed. The measurements were realized with a high spatial resolution detector mainly based on silicon microstrips showing the effect on particle trajectories of bent silicon crystals in several configurations. The proton beam was deviated in a direction opposite to that of channeling by 12-14 mrad, which is 1.3 times the critical angle, with an efficiency greater than 97% in a range of the proton-to-crystal incident angle as wide as the bending angle of crystallographic planes. This evidence opens new perspectives for m...

  19. A new family of four-ring bent-core nematic liquid crystals with highly polar transverse and end groups

    Directory of Open Access Journals (Sweden)

    Kalpana Upadhyaya

    2013-01-01

    Full Text Available Non-symmetrically substituted four-ring achiral bent-core compounds with polar substituents, i.e.., chloro in the bent or transverse direction in the central core and cyano in the lateral direction at one terminal end of the molecule, are designed and synthesized. These molecules possess an alkoxy chain attached at only one end of the bent-core molecule. The molecular structure characterization is consistent with data from elemental and spectroscopic analysis. The materials thermal behaviour and phase characterization have been investigated by differential scanning calorimetry and polarizing microscopy. All the compounds exhibit a wide-ranging monotropic nematic phase.

  20. Proton and Pb ion beam extraction experiments with bent crystals at the CERN-SPS

    CERN Document Server

    Elsener, K; Klem, J T; CERN. Geneva. SPS and LEP Division

    1997-01-01

    Extraction of particle beams from the CERN-SPS using bent silicon crystals is described. A summary of the early results is given. Emphasis is on the recent experiments, in particular on the energy dependence of proton extraction at 14, 120 and 270 GeV. 'U-shaped' crystals of different thickness and with a different miscut angle have been compared at 120 GeV. Non-linear excitation of the beam was used in one experiment, with the aim to achieve larger impact parameters - the results show a particular behaviour in the tails of the beam. Finally, the first experimental result on extraction of a 22 TeV fully stripped Pb ion beam with a bent crystal is also described.

  1. CMS Pixel Telescope Addition to T-980 Bent Crystal Collimation Experiment at the Tevatron

    CERN Document Server

    Rivera, Ryan; Johnson, Todd; Kwan, Simon; Lundberg, Carl; Still, Dean; Prosser, Alan; Uplegger, Lorenzo; Zagel, Jim; Zvodaya, Viktoriya

    2012-01-01

    An enhancement to the T-980 bent crystal collimation experiment at the Tevatron has been completed. The enhancement was the installation of a pixel telescope inside the vacuum-sealed beam pipe of the Tevatron. The telescope is comprised of six CMS PSI46 pixel plaquettes, arranged as three stations of horizontal and vertical planes, with the CAPTAN system for data acquisition and control. The purpose of the pixel telescope is to measure beam profiles produced by bent crystals under various conditions. The telescope electronics inside the beam pipe initially were not adequately shielded from the image current of the passing beams. A new shielding approach was devised and installed, which resolved the problem. The noise issues encountered and the mitigating techniques are presented herein, as well as some preliminary results from the telescope.

  2. Analysis of distribution of critical current of bent-damaged Bi2223 composite tape

    Energy Technology Data Exchange (ETDEWEB)

    Ochiai, S; Okuda, H; Hojo, M [Graduate School of Engineering, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606- 8501 (Japan); Sugano, M [Graduate School of Engineering, Kyoto University, Kyoto-Daigaku Katsura, Nishikyo-ku, Kyoto 615-8530 (Japan); Osamura, K [Research Institute for Applied Sciences, Sakyo-ku, Kyoto 606-8202 (Japan); Kuroda, T; Kumakura, H; Kitaguchi, H; Itoh, K; Wada, H, E-mail: shojiro.ochiai@materials.mbox.media.kyoto-u.ac.jp [National Institute for Materials Science, 1-2-1, Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

    2011-10-29

    Distributions of critical current of damaged Bi2223 tape specimens bent by 0.6, 0.8 and 1.0% were investigated analytically with a modelling approach based on the correlation of damage evolution to distribution of critical current. It was revealed that the distribution of critical current is described by three parameter Weibull distribution function through the distribution of the tensile damage strain of Bi2223 filaments that determines the damage front in bent-composite tape. Also it was shown that the measured distribution of critical current values can be reproduced successfully by a Monte Carlo simulation using the distributions of tensile damage strain of filaments and original critical current.

  3. The High-Redshift Clusters Occupied by Bent Radio AGN (COBRA) Survey

    CERN Document Server

    Paterno-Mahler, R; Ashby, M L N; Brodwin, M; Wing, J D; Anand, G; Decker, B; Golden-Marx, E

    2016-01-01

    We present 238 high-redshift galaxy cluster candidates based on galaxy overdensities in the Spitzer/IRAC imaging of the fields surrounding 646 bent, double-lobed radio sources drawn from the Clusters Occupied by Bent Radio AGN (COBRA) Survey. The COBRA sources were chosen as objects in the VLA FIRST survey that lack optical counterparts in the Sloan Digital Sky Survey (SDSS) to a limit of $m_r=22$, making them likely to lie at high redshift. This is confirmed by our observations: the redshift distribution of COBRA sources with estimated redshifts peaks near $z=1$, and extends out to $z\\approx3$. Cluster candidates were identified by comparing our sources to a background field and searching for overdensities. Forty-one of these sources are quasars with known spectroscopic redshifts, which may be tracers of some of the most distant clusters known.

  4. CMS Pixel Telescope Addition to T-980 Bent Crystal Collimation Experiment at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Rivera, Ryan; Annala, Jerry; Johnson, Todd; Kwan, Simon; Lundberg, Carl; Still, Dean; Prosser, Alan; Uplegger, Lorenzo; Zagel, Jim; Zvodaya, Viktoriya; /Fermilab

    2011-09-14

    An enhancement to the T-980 bent crystal collimation experiment at the Tevatron has been completed. The enhancement was the installation of a pixel telescope inside the vacuum-sealed beam pipe of the Tevatron. The telescope is comprised of six CMS PSI46 pixel plaquettes, arranged as three stations of horizontal and vertical planes, with the CAPTAN system for data acquisition and control. The purpose of the pixel telescope is to measure beam profiles produced by bent crystals under various conditions. The telescope electronics inside the beam pipe initially were not adequately shielded from the image current of the passing beams. A new shielding approach was devised and installed, which resolved the problem. The noise issues encountered and the mitigating techniques are presented herein, as well as some preliminary results from the telescope.

  5. A continuum model of piezoelectric potential generated in a bent ZnO nanorod

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Z Z; Wen, L Y; Wu, D M [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215125 (China); Wang, X F; Zhang, X A; Chang, S L, E-mail: zzshao2009@gmail.co [Center of Materials Science, College of Science, National University of Defense Technology, Changsha 410073 (China)

    2010-06-23

    A continuum model of piezoelectric potential generated in a bent ZnO nanorod cantilever is presented by means of the first piezoelectric effect approximation. The analytical solution of the model shows that the piezoelectric potential in the nanorod is proportional to the lateral force but is independent along the longitudinal direction. The electric potential in the tensile area and that in the compressive area are antisymmetric in the cross section of the nanorod, which makes the nanorod a 'parallel plate capacitor' for piezoelectric nanodevices, such as a nanogenerator. The magnitude of piezoelectric potential for a ZnO nanorod of 50 nm diameter and 600 nm length bent by a 80 nN lateral force is about 0.27 V, which is in good agreement with the finite element method calculation.

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

    Science.gov (United States)

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

    2016-11-01

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

  7. Improving the energy resolution of bent crystal X-ray spectrometers with position-sensitive detectors.

    Science.gov (United States)

    Honkanen, Ari Pekka; Verbeni, Roberto; Simonelli, Laura; Moretti Sala, Marco; Al-Zein, Ali; Krisch, Michael; Monaco, Giulio; Huotari, Simo

    2014-07-01

    Wavelength-dispersive high-resolution X-ray spectrometers often employ elastically bent crystals for the wavelength analysis. In a preceding paper [Honkanen et al. (2014). J. Synchrotron Rad. 21, 104-110] a theory for quantifying the internal stress of a macroscopically large spherically curved analyser crystal was presented. Here the theory is applied to compensate for the corresponding decrease of the energy resolution. The technique is demonstrated with a Johann-type spectrometer using a spherically bent Si(660) analyser in near-backscattering geometry, where an improvement in the energy resolution from 1.0 eV down to 0.5 eV at 9.7 keV incident photon energy was observed.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-08-31

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

  9. Stig Sundell at the bent crystal X-ray spectrometer for the X-ray shift experiment.

    CERN Multimedia

    1976-01-01

    The bent crystal X-ray spectrometer is being used to measure small shifts in the frequencies of X-rays emitted from the lower electron energy levels, in order to learn about the size of the nuclei concerned

  10. Extragalactic Jets as Probes of Distant Clusters of Galaxies and the Clusters Occupied by Bent Radio AGN (COBRA) Survey

    CERN Document Server

    Blanton, Elizabeth L; Wing, Joshua D; Ashby, M L N; Golden-Marx, Emmet; Brodwin, Mark; Douglass, E M; Randall, Scott W; Clarke, T E

    2014-01-01

    We are conducting a large survey of distant clusters of galaxies using radio sources with bent jets and lobes as tracers. These radio sources are driven by AGN and achieve their bent morphologies through interaction with the surrounding gas found in clusters of galaxies. Based on low-redshift studies, these types of sources can be used to identify clusters very efficiently. We present initial results from our survey of 653 bent-double radio sources with optical hosts too faint to appear in the SDSS. The sample was observed in the infrared with Spitzer, and it has revealed $\\sim$200 distant clusters or proto-clusters in the redshift range $z\\sim0.7 - 3.0$. The sample of bent-doubles contains both quasars and radio galaxies enabling us to study both radiative and kinetic mode feedback in cluster and group environments at a wide range of redshifts.

  11. Observation of nuclear dechanneling length reduction for high energy protons in a short bent crystal

    Directory of Open Access Journals (Sweden)

    W. Scandale

    2015-04-01

    Full Text Available Deflection of 400 GeV/c protons by a short bent silicon crystal was studied at the CERN SPS. It was shown that the dechanneling probability increases while the dechanneling length decreases with an increase of incident angles of particles relative to the crystal planes. The observation of the dechanneling length reduction provides evidence of the particle population increase at the top levels of transverse energies in the potential well of the planar channels.

  12. First results on proton extraction from the CERN-SPS with a bent crystal

    Science.gov (United States)

    Akbari, H.; Altuna, X.; Bardin, S.; Bellazzini, R.; Biryukov, V.; Brez, A.; Bussa, M. P.; Busso, L.; Calcaterra, A.; Carboni, G.; Costantini, F.; de Sangro, R.; Elsener, K.; Ferioli, F.; Ferrari, A.; Ferri, G. P.; Ferroni, F.; Fidecaro, G.; Freund, A.; Guinand, R.; Gyr, M.; Herr, W.; Hilaire, A.; Jensen, B. N.; Klem, J.; Lanceri, L.; Maier, K.; Massai, M. M.; Mertens, V.; Møller, S. P.; Morganti, S.; Palamara, O.; Peraire, S.; Petrera, S.; Placidi, M.; Santacesaria, R.; Scandale, W.; Schmidt, R.; Taratin, A. M.; Tosello, F.; Uggerhøj, E.; Vettermann, B.; Vita, P. F.; Vuagnin, G.; Weisse, E.; Weisz, S.

    1993-09-01

    The feasibility of extracting protons from the halo of a high energy beam by means of a bent silicon crystal has been investigated. Protons diffusing from a GeV beam circulating in the SPS at CERN have been extracted at an angle of 8.5 mrad. Efficiencies of abour 10 percent, orders of magnitude higher than the values achieved previously, have been measured. The present results are promising in view of beam extraction from future multi-TeV proton accelerators.

  13. Liquid-crystalline hybrid materials based on [60]fullerene and bent-core structures.

    Science.gov (United States)

    Vergara, Jorge; Barberá, Joaquín; Serrano, José Luis; Ros, M Blanca; Sebastián, Nerea; de la Fuente, Rosario; López, David O; Fernández, Gustavo; Sánchez, Luis; Martín, Nazario

    2011-12-23

    What a core-ker! By the appropriate combination of promesogenic bent-core structures and the C(60)  unit, lamellar polar liquid-crystal phases were induced. The supramolecular organization of the functional fullerene-based assemblies, the temperature range of the soft phase, the stabilization of the mesophase-like order at room temperature, and the molecular switching under an electric field can be tuned, depending on the molecular structure.

  14. A relationship between the nonexistence of generalized bent functions and class groups

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A new result on the nonexistence of generalized bent functions is presented by using properties of the decomposition law of primes in cyclotomic fields and properties of solutions of some Diophantine equations. At the same time,a method is given which can be used to simplify the known results. Then we give the bounds and the meaning in algebraic number theory of the parameters in our results.

  15. The signs B and B-bent in Israeli sign language according to the theory of Phonology as Human Behavior.

    Science.gov (United States)

    Fuks, Orit; Tobin, Yishai

    2008-01-01

    The purpose of the present research is to examine which of the two factors: (1) the iconic-semiotic factor; or (2) the human-phonetic factor is more relevant in explaining the appearance and distribution of the hand shape B-bent in Israeli Sign Language (ISL). The B-bent shape has been the subject of much attention in sign language research revolving around the question of its status as a phoneme. The arguments supporting the phonemic status of the B-bent hand shape have been primarily based on the semiotic opposition between the hand shape B and the hand shape B-bent. It has been claimed that in Italian Sign Language the hand shape B is perceptually distinct from the hand shape B-bent, i.e. in opposition to the general, neutral, unmarked meaning of the hand shape B, the iconic hand shape B-bent has a more narrow, specific and marked meaning: DELIMIT. The B-bent hand shape appears in spatial-temporal signs such as "a little before, ahead, postpone or behind". In these signs the iconic structure of the hand shape B-bent is utilized to mark borders in space and time. The arguments opposing the perceptual/phonemic distinction between these hand shapes is based on the human-phonetic factor, i.e. the need to reduce the effort on the part of the wrist joints in specific phonetic environments. We performed a quantitative and qualitative content analysis of the distribution of the basic units of 560 lexical signs taken from a stratified random sample from the ISL dictionary. The results were analyzed in the framework of the sign-oriented linguistic theory of the Columbia School including the theory of Phonology as Human Behavior. Our data revealed that the B-bent hand shape--as all the "building blocks" of the ISL--is a morpho-phonemic unit. We found that there is not only a phonemic distinction between hand shape B and hand shape B-bent in ISL (based on minimal pairs), but there is also a perceptual distinction between them. The qualitative analysis shows that the

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

    CERN Document Server

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

    1999-01-01

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

  17. Channeling of fast ions through the bent carbon nanotubes: The extended two-fluid hydrodynamic model

    Science.gov (United States)

    Lazar, Karbunar; Duško, Borka; Ivan, Radović; Zoran, L. Mišković

    2016-04-01

    We investigate the interactions of charged particles with straight and bent single-walled carbon nanotubes (SWNTs) under channeling conditions in the presence of dynamic polarization of the valence electrons in carbon. This polarization is described by a cylindrical, two-fluid hydrodynamic model with the parameters taken from the recent modelling of several independent experiments on electron energy loss spectroscopy of carbon nano-structures. We use the hydrodynamic model to calculate the image potential for protons moving through four types of SWNTs at a speed of 3 atomic units. The image potential is then combined with the Doyle-Turner atomic potential to obtain the total potential in the bent carbon nanotubes. Using that potential, we also compute the spatial and angular distributions of protons channeled through the bent carbon nanotubes, and compare the results with the distributions obtained without taking into account the image potential. Project supported by the Funds from the Ministry of Education, Science and Technological Development of the Republic of Serbia (Grant No. 45005). Z. L. Mišković thanks the Natural Sciences and Engineering Research Council of Canada for Finacial Support.

  18. Channeling, Volume Reection and Gamma Emission Using 14GeV Electrons in Bent Silicon Crystals

    Energy Technology Data Exchange (ETDEWEB)

    Benson, Brandon [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-14

    High energy electrons can be deflected with very tight bending radius using a bent silicon crystal. This produces gamma radiation. As these crystals can be thin, a series of bent silicon crystals with alternating direction has the potential to produce coherent gamma radiation with reasonable energy of the driving electron beam. Such an electron crystal undulator offers the prospect for higher energy radiation at lower cost than current methods. Permanent magnetic undulators like LCLS at SLAC National Accelerator Laboratory are expensive and very large (about 100 m in case of the LCLS undulator). Silicon crystals are inexpensive and compact when compared to the large magnetic undulators. Additionally, such a high energy coherent light source could be used for probing through materials currently impenetrable by x-rays. In this work we present the experimental data and analysis of experiment T523 conducted at SLAC National Accelerator Laboratory. We collected the spectrum of gamma ray emission from 14 GeV electrons on a bent silicon crystal counting single photons. We also investigated the dynamics of electron motion in the crystal i.e. processes of channeling and volume reflection at 14 GeV, extending and building off previous work. Our single photon spectrum for the amorphous crystal orientation is consistent with bremsstrahlung radiation and the volume reflection crystal orientation shows a trend consistent with synchrotron radiation at a critical energy of 740 MeV. We observe that in these two cases the data are consistent, but we make no further claims because of statistical limitations. We also extended the known energy range of electron crystal dechanneling length and channeling efficiency to 14 GeV.

  19. Amber Clifford-Napoleone, Queerness in heavy metal music: metal bent

    OpenAIRE

    Hill, Rosemary Lucy

    2016-01-01

    Metal Bent is an important book that sheds new light on the topic of gender and sexuality in metal music. Its aims are to queer metal and reconfigure discussion of the genre around gender and sexuality, and to move on from thinking about metal as just for “the straight boys” (3). These aims are achieved through a discussion of the style and media coverage of various musicians, and the results of a survey and interviews with queer metal fans. Central are the assertions that metal is queer and ...

  20. New Binomial Bent Function over the Finite Fields of Odd Characteristic

    CERN Document Server

    Helleseth, Tor

    2009-01-01

    The $p$-ary function $f(x)$ mapping $\\mathrm{GF}(p^{4k})$ to $\\mathrm{GF}(p)$ given by $f(x)={\\rm Tr}_{4k}\\big(x^{p^{3k}+p^{2k}-p^k+1}+x^2\\big)$ is proven to be a weakly regular bent function and the exact values of its Walsh transform coefficients are found. The proof is based on a few new results in the area of exponential sums and polynomials over finite fields that may also be interesting as independent problems.

  1. High resolution x-ray and gamma ray imaging using diffraction lenses with mechanically bent crystals

    Science.gov (United States)

    Smither, Robert K.

    2008-12-23

    A method for high spatial resolution imaging of a plurality of sources of x-ray and gamma-ray radiation is provided. High quality mechanically bent diffracting crystals of 0.1 mm radial width are used for focusing the radiation and directing the radiation to an array of detectors which is used for analyzing their addition to collect data as to the location of the source of radiation. A computer is used for converting the data to an image. The invention also provides for the use of a multi-component high resolution detector array and for narrow source and detector apertures.

  2. Acoplamiento pelágico-bentónico: respuesta de la zona bentónica profunda a la sedimentación del florecimiento invernal de diatomeas en el lago oligotrófico Alchichica, Puebla, México

    OpenAIRE

    Javier Alcocer; Elva Escobar; Luis A. Oseguera

    2008-01-01

    El objetivo del presente estudio es reconocer la existencia de un acoplamiento pelágico-bentónico en el lago oligotrófico tropical Alchichica evaluando la respuesta de la zona bentónica profunda a la sedimentación del florecimiento invernal de diatomeas. Se midió la biomasa fitoplanctónica en la columna de agua a lo largo de un ciclo anual, al igual que la concentración de clorofila a sedimentaria. Alchichica es un lago monomíctico cálido con un periodo de circulación invernal y estratificaci...

  3. Deflection and Extraction of Pb Ions up to 33 TeV/c by a Bent Silicon Crystal

    Energy Technology Data Exchange (ETDEWEB)

    Arduini, G.; Biino, C.; Clement, M.; Cornelis, K.; Doble, N.; Elsener, K.; Ferioli, G.; Fidecaro, G.; Gatignon, L.; Grafstroem, P.; Gyr, M.; Herr, W.; Klem, J.; Mikkelsen, U.; Weisse, E. [SL Division, CERN, CH-1211 Geneva 23 (Switzerland); Mo/ller, S.P.; Uggerho/j, E. [ISA, Aarhus University (Denmark); Taratin, A. [JINR, Dubna (Russia); Freund, A. [ESRF, Grenoble (France); Keppler, P.; Major, J. [MPI fuer Metallforschung, Stuttgart (Germany)

    1997-11-01

    The first results from an experiment to deflect a beam of fully stripped, ultrarelativistic Pb{sup 82+} ions of 400 GeV/c per unit of charge, equivalent to 33 TeV/c , by means of a bent crystal are reported. Deflection efficiencies are as high as 14{percent}, in agreement with theoretical estimates. In a second experiment a bent crystal was used to extract 270 GeV/c -per-charge Pb{sup 82+} (22 TeV/c) ions from a coasting beam in the CERN-SPS, and a high extraction efficiency of up to 10{percent} was found. These represent the first measurements to demonstrate applications of bent crystals in high energy heavy ion beams. {copyright} {ital 1997} {ital The American Physical Society}

  4. Deflection and Extraction of Pb Ions up to 33 TeV/c by a Bent Silicon Crystal

    Science.gov (United States)

    Arduini, G.; Biino, C.; Clément, M.; Cornelis, K.; Doble, N.; Elsener, K.; Ferioli, G.; Fidecaro, G.; Gatignon, L.; Grafström, P.; Gyr, M.; Herr, W.; Klem, J.; Mikkelsen, U.; Weisse, E.; Møller, S. P.; Uggerhøj, E.; Taratin, A.; Freund, A.; Keppler, P.; Major, J.

    1997-11-01

    The first results from an experiment to deflect a beam of fully stripped, ultrarelativistic Pb82+ ions of 400 GeV/c per unit of charge, equivalent to 33 TeV/c, by means of a bent crystal are reported. Deflection efficiencies are as high as 14%, in agreement with theoretical estimates. In a second experiment a bent crystal was used to extract 270 GeV/c-per-charge Pb82+ \\(22 TeV/c\\) ions from a coasting beam in the CERN-SPS, and a high extraction efficiency of up to 10% was found. These represent the first measurements to demonstrate applications of bent crystals in high energy heavy ion beams.

  5. Deflection and extraction of Pb ions up to 33 TeV/c by a bent silicon crystal

    CERN Document Server

    Arduini, Gianluigi; Clément, M; Cornelis, Karel; Doble, Niels T; Elsener, K; Ferioli, G; Fidecaro, Giuseppe; Freund, A; Gatignon, L; Grafström, P; Gyr, Marcel; Herr, Werner; Keppler, P; Klem, J T; Major, J V; Mikkelsen, U; Møller, S P; Taratin, A M; Uggerhøj, Erik; Weisse, E

    1997-01-01

    The first results from an experiment to deflect a beam of fully stripped, ulta-relativistic Pb ions of 400 GeV/c per unit of charge, equivalent to 33 TeV/c, by means of a bent crystal are reported. Deflection efficiencies are as high as 14%, in agreement with theoretical predictions. In a second experiment a bent crsytal was used to extract 270 GeV/c per charge Pb82+ (22 TeV/c) ions from a coasting beam in the CERN-SPS, and a high extraction efficiency of up to 10% was found. These represent the first measurements to demonstrate applications of bent crystals in high energy heavy ion beams.

  6. Cell Area and Strut Distribution Changes of Bent Coronary Stents: A Finite Element Analysis

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yang; WU Wei; YANG Da-zhi; QI Min

    2009-01-01

    Coronary stents are metal coils or mesh tubes delivered to blocked vessels through catheters, which are expanded by balloons to reopen and scaffold target vessels. Recently,special drugs are carried by stents (drug-eluting stents) to further reduce in-stent restenosis rate after stenting procedure. However,continual study on biomechanical characteristics of stents is necessary for better interactions between stents and tissue, or to provide a more suitable drug loading platform for drug-eluting stents. The purpose of this paper is to show how finite element methods can be used to study cell area and strut distribution changes of bent coronary stents. A same bending deformation was applied to two commercial coronary stent models by a rigid curved vessel. Results show that the stent design influenced the changes of cell area and strut distribution under bending situation. The stent with links had more cell area changes at outer curvature, and the stent with peak-peak (><) strut design could have strut contact and overlapping at inner curvature. In conclusion, this finite element method can be used to study and compare cell area and strut distribution changes of bent stents,and to provide a convenient tool for designers in testing and improving biomechanical characteristics of new stents.

  7. Measuring the x-ray resolving power of bent potassium acid phthalate diffraction crystalsa)

    Science.gov (United States)

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

    2014-11-01

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

  8. Investigation of Momentum Resolution in Straight vs Bent Large End-Cap Chambers

    CERN Document Server

    Levin, D S

    1999-01-01

    We report on a calculation of momentum resolution for muons incident on the large end-cap chambers. The impact on the resolution of two chamber designs was evaluated: Those constructed with straight drift tubes are compared to the ATLAS baseline design in which chambers are bent such that tube axes conform to the catenary of their respective anode wires. The analysis was performed using the GARFIELD program to calculate drift tube time-to-space functions. ATLAS muon system code packages LHCTOR and MUONBOX were used to generate tracks, hits and momentum reconstruction. We find that, for straight tube chambers compared to bent ones, the overall degradation in momentum resolution, averaged over all of the largest of the so called large end-cap chambers (EML4-5 and EOL3 in the pseudo-rapidity range$1.02 < \\eta <1.49$), is very small for muon transverse momentum $P_t = 500 $ Gev and negligible for $P_t \\le 100 $ Gev. When the intermediate large end-cap chambers (EEL1 and EEL2) are considered no momentum degr...

  9. Bent π-conjugated systems composed of three-dimensional benzoannulenes.

    Science.gov (United States)

    Nishiuchi, Tomohiko; Iyoda, Masahiko

    2015-02-01

    This article describes bent π-conjugated systems composed of alternating o-phenylene and Z-vinylene units. all-Z-[n]Benzo[4n]annulenes are higher homologues of dibenzocyclooctatetraene (DBCOT) with a concave π system, and attempts were made to convert [20]- and [24]annulenes having partial belt structures of fullerenes and carbon nanotubes into [10]- and [12]phenacenes. A bent π-conjugated system composed of two DBCOT units showed dynamic syn-anti equilibrium in solution and behaved as dynamic molecular tweezers (DMTs). The syn isomers of the DMTs formed blue charge-transfer complexes with DDQ in solution, and this complexation and color change were applied to thermochromism. Furthermore, DMTs having two CN groups on each COT ring exhibited crystalline-state emission in the presence of solvent molecules, although almost no emission was observed in solution or the solid state. Based on this crystalline-state emission, a vapochromic system was established. The multifunctional properties of DMTs caused by the flexibility of the nonplanar π system are summarized.

  10. New results from the CERN-SPS beam deflection experiments with bent crystals

    Science.gov (United States)

    Baurichter, A.; Kirsebom, K.; Medenwaldt, R.; Møller, S. P.; Worm, T.; Uggerhøj, E.; Mikkelsen, U.; Graftström, P.; Gatignon, L.; Elsener, K.; Doble, N.; Biino, C.; Freund, A.; Vilakazi, Z.; Hage-Ali, M.; Siffert, P.; Clément, M.

    1996-10-01

    Results from five distinct bending experiments performed recently in the H8 beam at CERN are presented. Firstly, deflection of a positive pion beam at 200 GeV/c is compared to the "standard" 450-GeV/c proton beam for a bending angle of 3.1 mrad along the (111) plane in a 50 mm silicon crystal. Second, deflection of negative pions at 200 GeV/c is investigated for the same crystal, for incidence along the (111) plane as well as the axis. Small deflection effects are seen, but no negative particles are bent through the full bending angle of the crystal. Third, the first results from beam deflection at high energy using a germanium crystal are shown. Slightly higher deflection efficiencies than for silicon are seen for large bending angles, but significantly smaller than expected for such a crystal with higher atomic number. Fourth, deflection efficiencies using a strongly irradiated silicon crystal have been measured for the first time, and a small reduction in efficiency is seen in the irradiated region. Finally, deflection of positive particles using axial alignment of a bent silicon crystal has been investigated at 450 GeV/c. Qualitatively similar behaviour as in previous experiments at 12 GeV/c is seen; the beam splits into several beams corresponding to the different planes, and even weak planes are observed.

  11. Immunogold-silver staining (IGSS) based U-bent fiberoptic sandwich biosensor

    Science.gov (United States)

    Ramakrishna, B.; Sai, V. V. R.

    2016-11-01

    An evanescent wave absorbance (EWA) based U-bent fiberoptic sandwich immunobiosensor with human IgG detection limits of 6.67 fM (1 pg/ml of human IgG) and 66.7 aM (10 fg/ml of HIgG) is demonstrated by exploiting immunogold labels and subsequently silver enhancement respectively. Such very low detection limits were achieved with the help of enhanced evanescent filed at the bend region of U-bent optical fiber probe that allows efficient interaction of light with 40 nm immunogold labels on the probe surface resulting in measurable optical absorbance changes. The other significant advantages of the demonstrated sensing scheme are low cost optoelectronic instrumentation consisting of an commercial green LED and a photodetector (S150C, Thorlabs Inc.), small volumes of sample and immunogold reagent each of 25 μl and rapid detection in 20 min. These results from the plasmonic fiberoptic biosensor demonstrate its huge potential for development of point-of-care diagnostic devices for sensitive and rapid detection of analytes.

  12. Measuring the X-ray Resolving Power of Bent Potassium Acid Phthalate Diffraction Crystals

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-11-01

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

  13. Experimentally determining the relative efficiency of spherically bent germanium and quartz crystals

    Science.gov (United States)

    Brown, G. V.; Beiersdorfer, P.; Hell, N.; Magee, E.

    2016-11-01

    We have used the EBIT-I electron beam ion trap at the Lawrence Livermore National Laboratory and a duplicate Orion High Resolution X-ray Spectrometer (OHREX) to measure the relative efficiency of a spherically bent quartz (10 1 ¯ 1) crystal (2d = 6.687 Å) and a spherically bent germanium (111) crystal (2d = 6.532 Å). L-shell X-ray photons from highly charged molybdenum ions generated in EBIT-I were simultaneously focussed and Bragg reflected by each crystal, both housed in a single spectrometer, onto a single CCD X-ray detector. The flux from each crystal was then directly compared. Our results show that the germanium crystal has a reflection efficiency significantly better than the quartz crystal, however, the energy resolution is significantly worse. Moreover, we find that the spatial focussing properties of the germanium crystal are worse than those of the quartz crystal. Details of the experiment are presented, and we discuss the advantages of using either crystal on a streak-camera equipped OHREX spectrometer.

  14. On the discrete spectrum of the Dirac operator on bent chain quantum graph

    Directory of Open Access Journals (Sweden)

    Belov Michail

    2017-01-01

    Full Text Available We study Dirac operators on an infinite quantum graph of a bent chain form which consists of identical rings connected at the touching points by δ-couplings with a parameter α ∈ ℝ. We are interested in the discrete spectrum of the corresponding Hamiltonian. It can be non-empty due to a local (geometrical perturbation of the corresponding infinite chain of rings. The quantum graph of analogous geometry with the Schrodinger operator on the edges was considered by Duclos, Exner and Turek in 2008. They showed that the absence of δ-couplings at vertices (i.e. the Kirchhoff condition at the vertices lead to the absence of eigenvalues. We consider the relativistic particle (the Dirac operator instead of the Schrodinger one but the result is analogous. Quantum graphs of such type are suitable for description of grapheme-based nanostructures. It is established that the negativity of α is the necessary and sufficient condition for the existence of eigenvalues of the Dirac operator (i.e. the discrete spectrum of the Hamiltonian in this case is not empty. The continuous spectrum of the Hamiltonian for bent chain graph coincides with that for the corresponding straight infinite chain. Conditions for appearance of more than one eigenvalue are obtained. It is related to the bending angle. The investigation is based on the transfer-matrix approach. It allows one to reduce the problem to an algebraic task. δ-couplings was introduced by the operator extensions theory method.

  15. Peeling behavior and spalling resistance of CFRP sheets bonded to bent concrete surfaces

    Science.gov (United States)

    Yuan, Hong; Li, Faping

    2010-05-01

    In this paper, the peeling behavior and the spalling resistance effect of carbon fiber reinforced polymer (CFRP) sheets externally bonded to bent concrete surfaces are firstly investigated experimentally. Twenty one curved specimens and seven plane specimens are studied in the paper, in which curved specimens with bonded CFRP sheets can simulate the concrete spalling in tunnel, culvert, arch bridge etc., whereas plane specimens with bonded CFRP sheets can simulate the concrete spalling in beam bridge, slab bridge and pedestrian bridge. Three kinds of curved specimens with different radii of curvature are chosen by referring to practical tunnel structures, and plane specimens are used for comparison with curved ones. A peeling load is applied on the FRP sheet by loading a circular steel tube placed into the central notch of beam to debond CFRP sheets from the bent concrete surface, meanwhile full-range load-deflection curves are recorded by a MTS 831.10 Elastomer Test System. Based on the experimental results, a theoretical analysis is also conducted for the specimens. Both theoretical and experimental results show that only two material parameters, the interfacial fracture energy of CFRP-concrete interface and the tensile stiffness of CFRP sheets, are needed for describing the interfacial spalling behavior. It is found that the radius of curvature has remarkable influence on peeling load-deflection curves. The test methods and test results given in the paper are helpful and available for reference to the designer of tunnel strengthening.

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

    Science.gov (United States)

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

    2014-07-01

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

  17. Bent silicon crystals for the LHC collimation Studies with an ultrarelativistic proton beam

    CERN Document Server

    Hasan, Said; Scandale, Walter; Vallazza, Erik

    2007-01-01

    LHC is a source of new challenges in every HEP field; among these, the beam collimation requires an innovative approach. The H8RD22 collaboration is undertaking an intense study of bent crystal properties with the goal of using crystals as primary collimators. The thesis gives an introduction to the theory of channeling and its related phenomena in bent crystals explaining how these can be used to perform an efficient beam collimation. The pre-thesis experiments are described to introduce the scientific context in which the H8RD22 collaboration is working. The thesis core is the description of two beam tests held in Sept. 2006 and May 2007 on the CERN SPS H8 beamline with 400 GeV/c protons: the experimental setups and procedures are shown together with the analysis of the collected data. With the observation of the volume reflection for the first time at these energies and the use of multi crystal systems, these experiments are a clear indication that crystal collimation is a real possibility for the second p...

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

    CERN Multimedia

    Fabio Cerutti

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

  19. The Influence of Radiation Damage on the Deflection of High-Energy Beams in Bent Silicon Crystals

    CERN Document Server

    Biino, C; Doble, Niels T; Elsener, K; Gatignon, L; Grafström, P; Mikkelsen, U; Kirsebom, K; Møller, S P; Uggerhøj, Erik; Worm, T

    1996-01-01

    Experimental results obtained for deflection of 450 GeV/c protons channeling along the {111} planes in a bent, strongly irradiated silicon crystal are presented. A comparison between the deflection efficiencies in irradiated areas and non-irradiated areas in the crystal shows that irradiation by 2.4 · 1020 protons/cm2 leads to a reduction of around 30 % in deflection efficiency. As a consequence, beam-splitting and extraction from an accelerator by means of a bent crystal are feasible solutions at high energies even for intense beams and during long periods.

  20. Bent Si monochromator—multi-detector neutron diffractometer installed at B4 super-mirror thermal guide tube in KUR

    Science.gov (United States)

    Achiwa, N.; Kawano, S.; Hino, M.; Mikula, P.; Ono, M.; Fukunaga, T.

    2004-08-01

    A new multi-detector neutron diffractometer has been installed at B4 thermal supermirror neutron guide in KUR, using a new bent Si monochromator developed by Mikula et al. and Ono et al.. Here we report resolutions of powder diffraction patterns by the multi-detector neutron diffractometer, which mainly depend on a radius of sample. Bragg diffraction optics by bent perfect crystal shows improvement of resolution without loss of luminosity and the multi- detector on the same 2 θ arm can gain the intensity without loosing resolution.

  1. Broadband tunable external cavity laser using a bent-waveguide quantum-dot superluminescent diode as gain device

    Institute of Scientific and Technical Information of China (English)

    Wu Jian; Lü Xue-Qin; Jin Peng; Meng Xian-Quan; Wang Zhan-Guo

    2011-01-01

    A broadband tunable grating-coupled external cavity laser is realized by employing a self-assembled InAs/GaAs quantum-dot (QD) superluminescent diode (SLD) as the gain device. The SLD device is processed with a bent-waveguide structure and facet antireflection (AR) coating. Tuning bandwidths of 106 nm and 117 nm are achieved under 3-A and 3.5-A injection currents, respectively. The large tuning range originates essentially from the broad gain spectrum of self-assembled QDs. The bent waveguide structure combined with the facet AR coating plays a role in suppressing the inner-cavity lasing under a large injection current.

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

    Energy Technology Data Exchange (ETDEWEB)

    Maynadie, J.; Berthet, J.C.; Thuery, P.; Ephritikhine, M. [CEA Saclay, DSM, DRECAM, Serv Chim Mol, Lab Claude Frejacques, CNRS URA 331, F-91191 Gif Sur Yvette, (France)

    2007-07-01

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

  3. Specific distribution behavior of a ternary mixture of solvents fed into bent and wound microchannels in microchips.

    Science.gov (United States)

    Nishiyama, Kei; Murata, Masaharu; Hashimoto, Masahiko; Tsukagoshi, Kazuhiko

    2013-01-01

    The tube radial distribution of ternary solvents (water-hydrophilic/hydrophobic organic mixture) fed into bent and wound microchannels in a microchip was examined by fluorescence observations of dyes dissolved in the solvents under laminar flow conditions. Four kinds of microchips incorporating bent microchannels were used, together with a microchip with a straight channel. The microchannels had different bending times (2, 4, or 12 times), bending radii (0.8, 2.3, or 3 mm), and total channel lengths (80, 120, 200, or 500 mm). A water-acetonitrile (hydrophilic)-ethyl acetate (hydrophobic) mixture containing relatively hydrophilic Eosin Y (green) and hydrophobic perylene (blue) was delivered into the bent microchannels in the microchips. The fluorescence of the green and blue dyes enabled us to observe the specific radial distribution behavior of the ternary solvents in the bent micro channels at 0°C, including liquid-liquid interfaces. Further, the radial distribution pattern of the solvents was clearly observed in the wound microchannel (bending radius, ca. 0.1 mm; real total channel length, 500 mm; and apparent straight channel length, 40 mm) at 20°C (room temperature) as well as 0°C. It was found that the radial distribution behaviors of the solvents were successfully generated in even specific microchannels including various types of curves under the present conditions.

  4. Standing helicon induced by a rapidly bent magnetic field in plasmas

    Science.gov (United States)

    Takahashi, Kazunori; Takayama, Sho; Komuro, Atsushi; Ando, Akira; Plasma physics Team

    2016-09-01

    An electron energy probability function and an rf magnetic field are measured in an rf hydrogen helicon source, where axial and transverse static magnetic fields are applied to the source by solenoids and to the diffusion chamber by filter magnets, respectively. It is demonstrated that the helicon wave is reflected by the rapidly bent magnetic field and the resultant standing wave heats the electrons between the source and the magnetic filter, while the electron cooling effect by the magnetic filter is maintained. It is interpreted that the standing wave is generated by the presence of spatially localized change of a refractive index. The application to the hydrogen negative ion source used for the neutral beam injection system for fusion plasma heating is discussed. This work is partially supported by grant-in-aid for scientific research (16H04084 and 26247096) from the Japan Society for the Promotion of Science.

  5. Performance of bent-crystal x-ray microscopes for high energy density physics research.

    Science.gov (United States)

    Schollmeier, Marius S; Geissel, Matthias; Shores, Jonathon E; Smith, Ian C; Porter, John L

    2015-06-01

    We present calculations for the field of view (FOV), image fluence, image monochromaticity, spectral acceptance, and image aberrations for spherical crystal microscopes, which are used as self-emission imaging or backlighter systems at large-scale high energy density physics facilities. Our analytic results are benchmarked with ray-tracing calculations as well as with experimental measurements from the 6.151 keV backlighter system at Sandia National Laboratories. The analytic expressions can be used for x-ray source positions anywhere between the Rowland circle and object plane. This enables quick optimization of the performance of proposed but untested, bent-crystal microscope systems to find the best compromise between FOV, image fluence, and spatial resolution for a particular application.

  6. The fourth Bent-toed Gecko of the genus Cyrtodactylus (Squamata: Gekkonidae) from Java, Indonesia.

    Science.gov (United States)

    Riyanto, Awal; Grismer, L Lee; Wood, Perry L

    2015-12-22

    Cyrtodactylus petani sp. nov. is a new species of Bent-toed Gecko from Java, Indonesia that had been masquerading under the name C. fumosus (Müller, 1895). The new species is differentiated from C. fumosus and all its Sundaland congeners by having the following combination of morphological characters: a maximum SVL of 57.2 mm; nine or ten supralabials; seven or eight infralabials; strongly tuberculate body and limbs; 20-25 paravertebral tubercles; 30-35 ventral scales; enlarged precloacal scales; enlarged femoral scales; 17-18 subdigital lamellae on the fourth toe; 31-35 continuous precloacal and femoral pores in males, pores absent in females; no precloacal groove; no enlarged median subcaudals; tubercles on anterior portion of tail; no reticulated pattern on top of head; a blotched dorsal pattern; and no paired, dark, semi-lunar shaped blotches on the nape.

  7. Silky bent grass resistance to herbicides: one year of monitoring in Belgium.

    Science.gov (United States)

    Henriet, F; Bodson, B; Morales, R Meza

    2013-01-01

    Silky bent grass (Apera spica-venti (L.) P. Beauv.) is a common weed of cereal crops widely spread in Northern and Easthern Europe (Germany, Czech Republic,...), Northern Asia, Siberia and Canada. Up to now, no resistant case has been detected in Belgium but some chemical weeding failures have been observed in Wallonia fields. During summer 2011, 37 seed samples of Apera spica-venti were collected in Wallonia and submitted to resistance tests in controlled conditions. Three modes of action were tested: acetyl coenzyme-A carboxylase inhibitors (pinoxaden and cycloxydim), acetolactate synthase inhibitors (mesosulfuron+iodosulfu-ron, pyroxsulam and sulfometuron) and photosynthesis inhibitors (isoproturon). One susceptible standard population was included in the test in order to validate it and to permit wild populations classification according to "R" rating system developed by Moss et al (2007). Most of populations were susceptible but some populations showed resistance to at least one of the three tested modes of action.

  8. 更多新惊喜——访Hegel总裁Bent Holter

    Institute of Scientific and Technical Information of China (English)

    沈剑萍

    2010-01-01

    这已经是Bent Holter(以下简作Bent)第四次到广州了。Bent这次显得特别高兴,因为Hegel的产品目前在中国拥有很高的知名度,销售业绩也达到了一个崭新的高度。笔者(以下简作“沈”)知道Bent一向有许多新的刨意,Hegel推出新产品的速度也很快,所以第一时间想知道他又绐国内的发烧友带来什么新的惊喜。

  9. Theoretical study of bifurcated bent blue-shifted hydrogen bonds CH2…Y

    Institute of Scientific and Technical Information of China (English)

    LI AnYong

    2008-01-01

    Ab initio quantum chemistry methods were applied to study the bifurcated bent hydrogen bonds Y… MP2/6-311++G(2df,2p) levels. The results show that in each complex there are two equivalent natural bond orbital analysis shows that these blue-shifted H-bonds are caused by three factors: large rehybridization; small direct intermolecular hyperconjugation and larger indirect intermolecular hy-perconjugation; large decrease of intramolecular hyperconjugation. The topological analysis of elec-tron density shows that in each complex there are three intermolecular critical points: there is one bond critical point between the acceptor atom Y and each hydrogen, and there is a ring critical point inside the tetragon YHCH, so these interactions are exactly H-bonding.

  10. Energy loss distributions of 7 TeV protons channeled in a bent silicon crystals

    Directory of Open Access Journals (Sweden)

    Stojanov Nace

    2013-01-01

    Full Text Available The energy loss distributions of relativistic protons axially channeled through the bent Si crystals, with the constant curvature radius, R = 50 m, are studied here. The proton energy is 7 TeV and the thickness of the crystal is varied from 1 mm to 5 mm, which corresponds to the reduced crystal thickness, L, from 2.1 to 10.6, respectively. The proton energy was chosen in accordance with the large hadron collider project, at the European Organization for Nuclear Research, in Geneva, Switzerland. The energy loss distributions of the channeled protons were generated by the computer simulation method using the numerical solution of the proton equations of motion in the transverse plane. Dispersion of the proton scattering angle caused by its collisions with the crystal’s electrons was taken into account. [Projekat Ministarstva nauke Republike Srbije, br. III 45006

  11. Channeling, volume reflection, and volume capture study of electrons in a bent silicon crystal

    Science.gov (United States)

    Wistisen, T. N.; Uggerhøj, U. I.; Wienands, U.; Markiewicz, T. W.; Noble, R. J.; Benson, B. C.; Smith, T.; Bagli, E.; Bandiera, L.; Germogli, G.; Guidi, V.; Mazzolari, A.; Holtzapple, R.; Tucker, S.

    2016-07-01

    We present the experimental data and analysis of experiments conducted at SLAC National Accelerator Laboratory investigating the processes of channeling, volume-reflection and volume-capture along the (111) plane in a strongly bent quasimosaic silicon crystal. These phenomena were investigated at 5 energies: 3.35, 4.2, 6.3, 10.5, and 14.0 GeV with a crystal with bending radius of 0.15 m, corresponding to curvatures of 0.053, 0.066, 0.099, 0.16, and 0.22 times the critical curvature, respectively. Based on the parameters of fitting functions we have extracted important parameters describing the channeling process such as the dechanneling length, the angle of volume reflection, the surface transmission, and the widths of the distribution of channeled particles parallel and orthogonal to the plane.

  12. CRYSTAL simulation code and modeling of coherent effects in a bent crystal at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Sytov, A.I., E-mail: alex_sytov@mail.ru [Research Institute for Nuclear Problems, Belarusian State University, Bobruiskaya str., 11, 220030 Minsk (Belarus); INFN Sezione di Ferrara, Dipartimento di Fisica e Scienze della Terra, Università di Ferrara, Via Saragat 1, 44100 Ferrara (Italy); Tikhomirov, V.V., E-mail: vvtikh@mail.ru [Research Institute for Nuclear Problems, Belarusian State University, Bobruiskaya str., 11, 220030 Minsk (Belarus)

    2015-07-15

    A CRYSTAL simulation code for particle tracking in crystals is introduced. Its essence consists in both adequate and fast sampling of proton trajectories in crystals which is crucial for both correct description of experiments and quantitative prediction of new effects. The H8 single-pass experiment at the CERN SPS as well as 7 TeV proton deflection by a bent crystal at the LHC are simulated. We predict the existence of dechanneling peaks corresponding to the planar channeling oscillations as well as describe the possibility of their observation at high energies, specifically at the LHC energy. An effect of excess over the amorphous level of ionization losses in the channeling mode was also found at 7 TeV.

  13. Elliptically-bent crystal spectrograph for X-ray diagnosis of laser-produced plasmas

    Institute of Scientific and Technical Information of China (English)

    Xiancai Xiong(熊先才); Xianxin Zhong(钟先信); Shali Xiao(肖沙里); Guohong Yang(杨国洪); Jie Gao(高洁)

    2004-01-01

    In order to measure spatially and temporarily resolved laser-produced plasma X-ray spectra in 0.2 - 2nm region, a novel two-channel elliptically-bent crystal spectrograph has been developed. Dispersive elements are LiF, PET, Mica, and KAP crystals, which cover Bragg angles in the range of 30 - 67.5degrees. Eccentricity and focal distance of twin ellipses are 0.9586 and 1350 mm, respectively. Spatially resolved spectrum is photographically recorded with an X-ray film or X-CCD camera in one channel, and temporarily resolved one is photographically recorded with an X-ray streak camera in another channel,thus spatially and temporarily resolved spectra can be simultaneously obtained. Spectral images were acquired with X-CCD and PET in SHENGUANG-Ⅱ laser facility, and experimental results show that the spectral resolution of the spectrograph is about 0.002 nm.

  14. Bent bone dysplasia (BBD)-FGFR2 type: the radiologic manifestations in early gestation

    Energy Technology Data Exchange (ETDEWEB)

    Handa, Atsuhiko; Okajima, Yuka; Kurihara, Yasuyuki [St. Luke' s International Hospital, Department of Radiology, Tokyo (Japan); Izumi, Noriko; Yamanaka, Michiko [St. Luke' s International Hospital, Department of Integrated Women' s Health, Tokyo (Japan)

    2016-02-15

    Bent bone dysplasia-fibroblast growth factor receptor 2 type (BBD-FGFR2) is a recently identified skeletal dysplasia caused by specific FGFR2 mutations, characterized by craniosynostosis and prenatal bowing of the long bones. Only a few cases have been published. We report an affected fetus terminated at 21 weeks of gestation. The clinical and radiologic manifestations mostly recapitulate previous descriptions; however we suggest additional hallmarks of this disorder in early gestation. These hallmarks include distinctive short, thick clavicles and wavy ribs, as well as vertebral bodies that showed striking anteroposterior shortening. Femoral fractures were also present in our case. Although craniosynostosis is a hallmark of the disease, clinicians should be aware that craniosynostosis might not be readily apparent on plain films early in gestation. (orig.)

  15. Polar order in columnar phase made of polycatenar bent-core molecules.

    Science.gov (United States)

    Gorecka, Ewa; Pociecha, Damian; Matraszek, Joanna; Mieczkowski, Jozef; Shimbo, Yoshio; Takanishi, Yoichi; Takezoe, Hideo

    2006-03-01

    Columnar phases made of polycatenar molecules with bent-shaped mesogenic cores are studied. The polar order in this system is associated with the change of the column building blocks from flat disks (Colh phase) into cones (Colh PA phase), which allows for axial polarization of the columns. The nature of the Colh and Colh PA phase transition changes from first order for short homologues to continuous for the longest one. This can be attributed to decreasing intercolumnar interactions due to broadening of the columnar scaffold made of partially melted terminal alkyl chains. Decrease of intercolumnar interactions is also responsible for a strong increase of the pretransitional fluctuations in the Colh phase. The mesophase observed for the longest homologues is reminiscent of the relaxor phase observed for solid crystals.

  16. Bent Shaped 1,3,4-Oxadiazole/Thiadiazole heterocyclic rings containing liquid crystals

    Indian Academy of Sciences (India)

    Chinnaiyan Selvarasu; Palaninathan Kannan

    2015-10-01

    Two series of bent shaped 1,3,4-oxadiazole/thiadiazole heterocyclic ring containing liquid crystalline (LC) compounds were synthesized and characterized by FT-IR, 1H, 13C-NMR and ESI-Mass spectro-scopic techniques. Liquid crystal properties were investigated by polarized optical microscopy and differential scanning calorimetry. All the compounds exhibited mesophases such as nematic, smectic A and smectic C phases. The liquid crystalline effects were ascertained by changing the central atom in the heterocyclic ring and by increasing the length of the terminal alkyloxy chains which bring considerable improvements on the mesomorphic properties. The absorption and emission spectral studies of all the compounds were investigated and confirmed.

  17. Monte Carlo N-Particle Tracking of Ultrafine Particle Flow in Bent Micro-Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Casella, Andrew M.; Loyalka, Sudarsham K.

    2016-02-16

    The problem of large pressure-differential driven laminar convective-diffusive ultrafine aerosol flow through bent micro-tubes is of interest in several contemporary research areas including; release of contents from pressurized containment vessels, aerosol sampling equipment, advanced scientific instruments, gas-phase micro-heat exchangers, and microfluidic devices. In each of these areas, the predominant problem is the determination of the fraction of particles entering the micro-tube that is deposited within the tube and the fraction that is transmitted through. Due to the extensive parameter restrictions of this class of problems, a Lagrangian particle tracking method making use of the coupling of the analytical stream line solutions of Dean and the simplified Langevin equation is quite a useful tool in problem characterization. This method is a direct analog to the Monte Carlo N-Particle method of particle transport extensively used in nuclear physics and engineering. In this work, 10 nm diameter particles with a density of 1 g/cm3 are tracked within micro-tubes with toroidal bends with pressure differentials ranging between 0.2175 and 0.87 atmospheres. The tubes have radii of 25 microns and 50 microns and the radius of curvature is between 1 m and 0.3183 cm. The carrier gas is helium, and temperatures of 298 K and 558 K are considered. Numerical convergence is considered as a function of time step size and of the number of particles per simulation. Particle transmission rates and deposition patterns within the bent micro-tubes are calculated.

  18. Corresponding-states behavior of SPC/E-based modified (bent and hybrid) water models

    Science.gov (United States)

    Weiss, Volker C.

    2017-02-01

    The remarkable and sometimes anomalous properties of water can be traced back at the molecular level to the tetrahedral coordination of molecules due to the ability of a water molecule to form four hydrogen bonds to its neighbors; this feature allows for the formation of a network that greatly influences the thermodynamic behavior. Computer simulations are becoming increasingly important for our understanding of water. Molecular models of water, such as SPC/E, are needed for this purpose, and they have proved to capture many important features of real water. Modifications of the SPC/E model have been proposed, some changing the H-O-H angle (bent models) and others increasing the importance of dispersion interactions (hybrid models), to study the structural features that set water apart from other polar fluids and from simple fluids such as argon. Here, we focus on the properties at liquid-vapor equilibrium and study the coexistence curve, the interfacial tension, and the vapor pressure in a corresponding-states approach. In particular, we calculate Guggenheim's ratio for the reduced apparent enthalpy of vaporization and Guldberg's ratio for the reduced normal boiling point. This analysis offers additional insight from a more macroscopic, thermodynamic perspective and augments that which has already been learned at the molecular level from simulations. In the hybrid models, the relative importance of dispersion interactions is increased, which turns the modified water into a Lennard-Jones-like fluid. Consequently, in a corresponding-states framework, the typical behavior of simple fluids, such as argon, is seen to be approached asymptotically. For the bent models, decreasing the bond angle turns the model essentially into a polar diatomic fluid in which the particles form linear molecular arrangements; as a consequence, characteristic features of the corresponding-states behavior of hydrogen halides emerge.

  19. Energy loss distributions of 7 TeV protons axially channeled in the bent Si crystal

    Science.gov (United States)

    Stojanov, Nace; Petrović, Srdjan

    2016-04-01

    In this article, the energy loss distributions of relativistic protons axially channeled in the bent Si crystal are studied. The crystal thickness is equal to 1 mm, which corresponds to the reduced crystal thickness, Λ, equal to 1.22, whereas the bending angle, α, was varied from 0 to 30 μrad. The proton energy of 7 TeV was chosen in accordance with the concept of using the bent crystals as a tool for selective deflection of the beam halo particles from the LUA9 experiment at LHC. For the continuum interaction potential of the proton and the crystal the Molière's expression was used and the energy loss of a proton was calculated by applying the trajectory dependent stopping power model. Further, the uncertainness of the scattering angle of the proton caused by its collisions with the electrons of the crystal and the divergence of the proton beam were taken into account. The energy loss distribution of the channeled protons was obtained via the numerical solution of the proton equations of motion in the transverse plane and the computer simulation method. The analysis of the obtained theoretical data shows that the shape of the energy loss distribution strongly depends on the horizontal or vertical direction of the curvature of the crystal. The number of dechanneled protons as a function of the bending angle also strongly depends on the direction of the crystal's curvature. As a result, the dechanneling rates and ranges, obtained from the Gompertz type sigmoidal fitting functions, have different sets of values for different bending orientations. We have also studied the influence of the proton beam divergence on the energy loss distribution of channeled protons.

  20. Adsorption Removal of Phenols from Water by CTMAB-Bent and HDBAC-Bent%CTMAB -膨润土和 HDBAC -膨润土吸附去除水中酚类有机污染物

    Institute of Scientific and Technical Information of China (English)

    王闻捷; 虞卉; 陈晨; 郑凯琳; 杨超颖; 徐立恒

    2015-01-01

    Aiming to the removal of phenols from water , organobentonites (HDBAC-Bent and CTMAB-Bent) were fabrica-ted with HDBAC and CTMAB as modifiers , and their structure were characterized with FTIR and SEM .The adsorption ca-pacities of organobentonites towards phenols from single-solute and bi-solute system were studied .It was found that the ad-sorption ability of the two organobentonites towards 2-naphthol was remarkably higher than that towards phenol .In the bi-solute system, the adsorption of 2-naphthol was hardly effected by coexisted phenol , while the existing of 2-naphthol dra-matically reduce the adsorption of phenol .Comparing to CTMAB-Bent, the adsorption ability of HDBAC-Bent towards 2-naphthol was much higher .%针对水中酚类有机污染物的去除,十六烷基二甲基苄基氯化铵( HDBAC )和十六烷基三甲基溴化铵( CT-MAB)为改性剂在制备了两种有机膨润土( HDBAC-Bent和CTMAB-Bent),并以红外光谱和扫描电子显微镜对有机膨润土的结构进行表征。同时,考察了有机膨润土对单一和复合污染体系中苯酚和2-萘酚的吸附性能,研究发现两种有机膨润土对2-萘酚的吸附能力远远大于对苯酚的吸附,在两种有机物共存时,2-萘酚的吸附受苯酚影响很少,而苯酚的吸附显著受到抑制。

  1. Free-living benthic marine invertebrates in Chile Invertebrados bentónicos marinos de vida libre en Chile

    Directory of Open Access Journals (Sweden)

    MATTHEW R LEE

    2008-03-01

    Full Text Available A comprehensive literature review was conducted to determine the species richness of all the possible taxa of free-living benthic marine invertebrates in Chile. In addition, the extent of endemism to the Pacific Islands and deep-sea, the number of non-indigenous species, and the contribution that the Chilean benthic marine invertebrate fauna makes to the world benthic marine invertebrate fauna was examined. A total of 4,553 species were found. The most speciose taxa were the Crustacea, Mollusca and Polychaeta. Species richness data was not available for a number of taxa, despite evidence that these taxa are present in the Chilean benthos. The Chilean marine invertebrate benthic fauna constitutes 2.47 % of the world marine invertebrate benthic fauna. There are 599 species endemic to the Pacific Islands and 205 in the deep-sea. There are 25 invasive or non-indigenous species so far identified in Chile. Though the Chilean fauna is speciose there is still a considerable amount of diversity yet to be described, particularly amongst the small bodied invertebrates and from the less well explored habitats, such as the deep-seaSe realizó una revisión exhaustiva de la literatura para determinar la riqueza de especies de todos los taxa de invertebrados bentónicos de vida libre en Chile. Además, se analizó el endemismo de invertebrados marinos bentónicos para las islas chilenas del Pacífico y el mar profundo y el número de especies no indígenas; del mismo modo que la contribución de estos invertebrados a la riqueza mundial de invertebrados bentónicos marinos. Para Chile se acumuló un total de 4.553 especies de invertebrados bentónicos. Los taxa con más especies fueron Crustacea, Mollusca y Polychaeta. En algunos taxa de invertebrados no se encontró información sobre la diversidad de especies presentes en Chile, a pesar de existir evidencia de que éstos están presentes en el bentos marino chileno. Los invertebrados bentónicos marinos

  2. Analysis of surface plasmon resonance in bent single-mode waveguides with metal-coated cladding by eigenmode expansion method.

    Science.gov (United States)

    Kulchin, Yu N; Vitrik, O B; Dyshlyuk, A V

    2014-09-08

    A numerical study is presented of surface plasmon waves excitation in a metal film applied to the cladding of a standard bent single-mode optical fiber. It was shown that by adjusting the bend radius and metal film thickness one can achieve effective coupling between the fiber fundamental mode and symmetric surface plasmon mode through the intermediary of whispering gallery modes supported by the cladding of the bent fiber. This effect is demonstrated to allow for refractometric measurement both in the wavelength and intensity-modulated regimes with a resolution of up to 10⁻⁸ RIU. Usage of standard noise reduction techniques for intensity-modulated optical signals promises further increase in accuracy.

  3. Leaning-type polar smectic-C phase in a freely suspended bent-core liquid crystal film.

    Science.gov (United States)

    Chattham, Nattaporn; Tamba, Maria-Gabriela; Stannarius, Ralf; Westphal, Eduard; Gallardo, Hugo; Prehm, Marko; Tschierske, Carsten; Takezoe, Hideo; Eremin, Alexey

    2015-03-01

    A rich variety of responsive behavior occurs in complex structured fluids due to their lower symmetries. On the other hand, fluid disorder tends to increase the symmetry of liquid crystal mesophases. Here, we report direct evidence for the existence of a mesophase with CS symmetry. The observations are based on optical studies of director inversion walls in freely suspended films in electric fields under obliquely incident light. This phase is distinguished by the polarization lying in the molecular tilt plane in freely suspended films. Such a low-symmetry polar fluid phase has been long predicted to occur in bent-core liquid crystals. The stability of this phase is attributed to the bent shape of the mesogens and dominating dispersion interactions.

  4. First Observation of the Deflection of a 33 TeV Pb Ion Beam in a Bent Silicon Crystal

    Science.gov (United States)

    Elsener, K.; Biino, C.; Clement, M.; Doble, N.; Gatignon, L.; Grafstrom, P.; Mikkelsen, U.; Taratin, A.; Møller, S. P.; Uggerhøj, E.

    1997-05-01

    The deflection of an ultra-relativistic, fully stripped Pb(82+) ion beam in a bent silicon crystal has been observed for the first time. The ions were provided by the CERN-SPS in the H4 beam at a momentum of 400 GeV/c/Z. A 60 mm long silicon crystal, bent over 50 mm to give a 4 mrad deflection angle, was used in this experiment. The measured Pb ion deflection efficiencies are comparable to the ones obtained with protons at an equivalent ratio p/Z, and are found to be about 15% for a beam with a divergence of 50 microradians (FWHM). The interaction rate observed in a background counter is reduced by about the same 15% when the crystal is well aligned with the beam. This corroborates further the channeling model, which predicts that channeled ions are steered away from regions of high electron densities as well as from the nuclei in the crystal.

  5. Focusing effect of bent GaAs crystals for gamma-ray Laue lenses: Monte Carlo and experimental results

    CERN Document Server

    Virgilli, E; Rosati, P; Bonnini, E; Buffagni, E; Ferrari, C; Stephen, J B; Caroli, E; Auricchio, N; Basili, A; Silvestri, S

    2015-01-01

    We report on results of observation of the focusing effect from the planes (220) of Gallium Arsenide (GaAs) crystals. We have compared the experimental results with the simulations of the focusing capability of GaAs tiles through a developed Monte Carlo. The GaAs tiles were bent using a lapping process developed at the cnr/imem - Parma (Italy) in the framework of the laue project, funded by ASI, dedicated to build a broad band Laue lens prototype for astrophysical applications in the hard X-/soft gamma-ray energy range (80-600 keV). We present and discuss the results obtained from their characterization, mainly in terms of focusing capability. Bent crystals will significantly increase the signal to noise ratio of a telescope based on a Laue lens, consequently leading to an unprecedented enhancement of sensitivity with respect to the present non focusing instrumentation.

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

    CERN Document Server

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

    2016-01-01

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

  7. First observation of multiple volume reflection by different planes in one bent silicon crystal for high-energy protons

    CERN Document Server

    Scandale, E; Bagli, E; Baricordi, S; Dalpiaz, P; Fiorini, M; Guidi, V; Mazzolari, A; Vincenzi, D; Milan, R; Della Mea, Gianantonio; Vallazza, E; Afonin, A G; Chesnokov, Yu A; Maisheev, V A; Yazynin, I A; Golovatyuk, V M; Kovalenko, A D; Taratin, A M; Denisov, A S; Gavrikov, Yu A; Ivanov, Yu M; Lapina, L P; Malyarenko, L G; Skorobogatov, V V; Suvorov, V M; Vavilov, S A; Bolognini, D; Hasan, S; Mattera, A; Prest, M; Tikhomirovl, V V

    2009-01-01

    Multiple volume reflection by different planes in a bent silicon crystal with its 111 axis orientation close to the beam direction was observed for the first time for 400 GeV/c protons at the CERN SPS. The proton beam was deflected to the side opposite to the crystal bend by an angle of about 67 μrad, which is five times larger than in a single volume reflection by the (110) bent planes. The registered efficiency of one side deflection was about 84%. It was shown that multiple volume reflection transforms to a single volume reflection when the orientation angle of the 111 axis relative to the beam direction is increased

  8. Sistemática de Foraminíferos Bentónicos de playa Gómez isla Gorgona

    Directory of Open Access Journals (Sweden)

    Londoño de Hoyos Concha

    1996-06-01

    Full Text Available One hundred species of benthonic Foraminifera grouped in 46 genera, 22 families, 9 superfamilies and 3 suborders were identified. The total number of individuals studied was 1.445; according to the data repported by the literature on benthonic Foraminifera, 77% of the individuals studied could be considered as in sifu fauna, the rernaining 23% are considered as displaced tests.Se identificaron 100 especies de foraminíferos bentónicos, agrupados en 46 géneros, 22 familias, 9 superfamilias y 3 subórdenes. El total de individuos estudiados es de 1.44'5; un 77% de ellos, de acuerdo con los registros en la literatura sobre distribución de foraminíferos bentónicos, se pueden considerar
    como fauna in situ, el 23% restante se considera como caparazones desplazados.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-02-15

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

  10. Optimization and Annual Average Power Predictions of a Backward Bent Duct Buoy Oscillating Water Column Device Using the Wells Turbine

    OpenAIRE

    Smith, Christopher; Willits, Steven; Bull, Diana; Fontaine, Arnold

    2014-01-01

    This paper presents work completed by The Applied Research Laboratory at The Pennsylvania State University, in conjunction with Sandia National Labs, on the optimization of the power conversion chain (PCC) design to maximize the Average Annual Electric Power (AAEP) output of an Oscillating Water Column (OWC) device. The design consists of two independent stages. First, the design of a floating OWC, a Backward Bent Duct Buoy (BBDB), and second the design of the PCC. The pneumatic power output ...

  11. Deflection of 32.8 TeV/c fully stripped Pb ions by means of a bent Si crystal

    CERN Document Server

    Biino, C; Doble, Niels T; Elsener, K; Gatignon, L; Grafström, P; Herr, Werner; Keppler, P; Major, J V; Mikkelsen, U; Taratin, A; Velasco, M

    2000-01-01

    New results on the deflection of fully stripped 32.8 TeV/c Pb ions in a bent Si crystal at the CERN-SPS are reported. Deflection efficiencies above 10% have been measured for deflection angles in the range 4-9 mrad.The effect of particle losses due to interaction in the crystal and other systematic errors have been carefully investigated. The experimental results are in agreement with theoretical calculations

  12. Deflection of 32.8 TeV/c fully stripped Pb ions by means of a bent Si crystal

    Energy Technology Data Exchange (ETDEWEB)

    Biino, C.; Clement, M.; Doble, N.; Elsener, K. E-mail: konrad.elsener@cern.ch; Gatignon, L.; Grafstroem, P.; Herr, W.; Keppler, P.; Major, J.; Mikkelsen, U.; Taratin, A.; Velasco, M

    2000-04-01

    New results on the deflection of fully stripped 32.8 TeV/c Pb ions in a bent Si crystal at the CERN-SPS are reported. Deflection efficiencies above 10% have been measured for deflection angles in the range 4-9 mrad. The effect of particle losses due to interaction in the crystal and other systematic errors have been carefully investigated. The experimental results are in agreement with theoretical calculations.

  13. Deflection of 32.8 TeV/c fully stripped Pb ions by means of a bent Si crystal

    Science.gov (United States)

    Biino, C.; Clément, M.; Doble, N.; Elsener, K.; Gatignon, L.; Grafström, P.; Herr, W.; Keppler, P.; Major, J.; Mikkelsen, U.; Taratin, A.; Velasco, M.

    2000-03-01

    New results on the deflection of fully stripped 32.8 TeV/c Pb ions in a bent Si crystal at the CERN-SPS are reported. Deflection efficiencies above 10% have been measured for deflection angles in the range 4-9 mrad. The effect of particle losses due to interaction in the crystal and other systematic errors have been carefully investigated. The experimental results are in agreement with theoretical calculations.

  14. Channeling and Radiation of 855 MeV Electrons and Positrons in Straight and Bent Tungsten (110) Crystals

    CERN Document Server

    Shen, H; Zhang, F S; Sushko, Gennady B; Korol, Andrei V; Solov'yov, Andrey V

    2016-01-01

    Planar channeling of 855 MeV electrons and positrons in straight and bent tungsten (110) crystal is simulated by means of the \\MBNExplorer software package. The results of simulations for a broad range of bending radii are analyzed in terms of the channel acceptance, dechanneling length, and spectral distribution of the emitted radiation. Comparison of the results with predictions of other theories as well as with the data for (110) oriented diamond, silicon and germanium crystals is carried out.

  15. Recent evolution and degradation of the bent Jatunraju glacier (Cordillera Blanca, Peru)

    Science.gov (United States)

    Emmer, Adam; Loarte, Edwin C.; Klimeš, Jan; Vilímek, Vít

    2015-01-01

    This article brings new insight into the recent evolution and degradation of the bent Jatunraju glacier in the northern part of the Cordillera Blanca, Peru. Analysis of topographical maps, aerial photos and satellite images covering a period of 66 years and a field survey performed in June 2013 and May 2014 helped to describe the geomorphological setting and ongoing processes. Recent evolution and degradation processes are also deduced from surface movements. Historical geodetic measurements (1967-1968; 1977-1984) and current LANDSAT images (2001-2013) were used to estimate surface velocities and changes in surface velocities over time. Our investigation showed that the most significant changes happened at an altitude of between 4300 and 4450 m asl. A significant decrease in surface velocities and increase in debris thickness indicate that this part of Jatunraju turned from a debris-covered glacier into an ice-cored rock glacier during the analyzed period. Particular parts of the article describe the cycle of formation and extinction of supraglacial lakes and the melting of buried (debris-covered) ice. A scenario of future evolution is outlined and discussed as well. We assume that ice degradation within the debris-covered glacier will continue and that the altitude of its presence will increase hand-in-hand with the changing environment.

  16. Theoretical study of bifurcated bent blue-shifted hydrogen bonds CH2…Y

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Ab initio quantum chemistry methods were applied to study the bifurcated bent hydrogen bonds Y… H2CZ (Z = O, S, Se) and Y…H2CZ2 (Z = F, Cl, Br) (Y = Cl-, Br-) at the MP2/6-311++G(d,p) and MP2/6-311++G(2df,2p) levels. The results show that in each complex there are two equivalent blue-shifted H-bonds Y…H—C, and that the interaction energies and blue shifts are large, the energy of each Y…H—C H-bond is 15-27 kJ/mol, and Δr(CH) = -0.1 - -0.5 pm and Δv(CH) = 30 - 80 cm-1. The natural bond orbital analysis shows that these blue-shifted H-bonds are caused by three factors: large rehybridization; small direct intermolecular hyperconjugation and larger indirect intermolecular hy- perconjugation; large decrease of intramolecular hyperconjugation. The topological analysis of elec- tron density shows that in each complex there are three intermolecular critical points: there is one bond critical point between the acceptor atom Y and each hydrogen, and there is a ring critical point inside the tetragon YHCH, so these interactions are exactly H-bonding.

  17. Numerical analysis of angular defects in bent plates using tone burst eddy-current thermography (TBET)

    Science.gov (United States)

    Libin, M. N.; Balasubramaniam, Krishnan; Maxfield, B. W.

    2013-01-01

    Tone Burst Eddy current Thermography (TBET) is a new hybrid, non-contacting, Non-Destructive Evaluation (NDT) method which employs a combination of Pulsed Eddy current Thermography (PEC) and Thermographic Non-Destructive Evaluation (TNDE). For understanding angular cracks, fundamental knowledge about the induced current density distribution in the component under test is required. Further, this information enables us to find the amount of heat produced at those locations and how it diffuses to the surface. This paper describes simulation work done for cracks set at an angle to the surface in flat and bent aluminum plates. The investigation is implemented by the simulating transient thermal distribution for 2D angular cracks via finite element package COMSOL multi-physics with AC/DC module and general heat transfer. At crack edges, induced current is seen concentrated thus indicating a localized high heating in those areas relative to other regions. A numerical study was also carried out by varying parameters like crack angle (0°, 22.5°, 45°, 67.5°) and crack length (0.6mm, 1.2mm, 1.8mm) the transient thermal distributions were compared for different plate bend angles (180°, 120°, 90°, 60°, 30°). TBET method was found well suited for the detection of service induced cracks, usually caused by either rolling contact fatigue or stress corrosion, with a high degree of sensitivity.

  18. Whole-body muscle MRI to detect myopathies in non-extrapyramidal bent spine syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Ohana, Mickael [Nouvel Hopital Civil - Hopitaux Universitaires de Strasbourg, Service de Radiologie B, Strasbourg (France); Durand, Marie-Christine [AP-HP - Hopital Raymond Poincare, Service de Neurologie, Garches (France); Marty, Catherine; Lazareth, Jean-Philippe [AP-HP - Hopital Raymond Poincare, Service de Rhumatologie, Garches (France); Maisonobe, Thierry [APH-HP - Hopital de la Pitie-Salpetriere, Service de Neuropathologie, Paris (France); Mompoint, Dominique; Carlier, Robert-Yves [AP-HP - Hopital Raymond Poincare, Service de Radiologie, Garches (France)

    2014-08-15

    Bent spine syndrome (BSS), defined as an abnormal forward flexion of the trunk resolving in supine position, is usually related to parkinsonism, but can also be encountered in myopathies. This study evaluates whole-body muscle MRI (WB-mMRI) as a tool for detecting underlying myopathy in non-extrapyramidal BSS. Forty-three patients (90 % women; 53-86 years old) with a non-extrapyramidal BSS were prospectively included. All underwent a 1.5-T WB-mMRI and a nerve conduction study. Muscle biopsy was performed if a myopathy could not be eliminated based on clinical examination and all tests. Systematic MRI interpretation focused on peripheral and axial muscle injury; spinal posture and incidental findings were also reported. WB-mMRI was completed for all patients, with 13 muscle biopsies ultimately needed and myopathy revealed as the final etiological diagnosis in five cases (12 %). All biopsy-proven myopathies were detected by the WB-mMRI. Relevant incidental MRI findings were made in seven patients. This study supports WB-mMRI as a sensitive and feasible tool for detecting myopathy in BSS patients. Associated with electroneuromyography, it can better indicate when a muscle biopsy is needed and guide it when required. Rigorous radiological interpretation is mandatory, so as not to miss incidental findings of clinical consequence. (orig.)

  19. Manufacturing of advanced bent crystals for Laue Optics for Gamma ObservationS (LOGOS)

    Energy Technology Data Exchange (ETDEWEB)

    Mazzolari, Andrea, E-mail: mazzolari@fe.infn.it [Department of Physics and Earth Sciences, University of Ferrara, Via Saragat 1/c, 44122 Ferrara (Italy); INFN, Section of Ferrara (Italy); Camattari, Riccardo; Bellucci, Valerio; Paternò, Gianfranco [Department of Physics and Earth Sciences, University of Ferrara, Via Saragat 1/c, 44122 Ferrara (Italy); INFN, Section of Ferrara (Italy); Scian, Carlo; Mattei, Giovanni [University of Padova, Department of Physics and Astronomy Galileo Galilei (Italy); Guidi, Vincenzo [Department of Physics and Earth Sciences, University of Ferrara, Via Saragat 1/c, 44122 Ferrara (Italy); INFN, Section of Ferrara (Italy)

    2015-07-15

    X- and γ-ray detection is currently a hot topic for a wide scientific community, spanning from astrophysics to nuclear medicine. However, lack of optics capable of focusing photons of energies in the energy range 0.1–1 MeV leaves the photon detection to a direct-view approach, resulting in a limited efficiency and resolution. The main scope of the INFN-LOGOS project is the development of technologies that enable manufacturing highly performing optical elements to be employed in the realization of hard X-ray lenses. Such lenses, typically named Laue lenses, consist of an ensemble of crystals disposed in concentric rings in order to diffract the incident radiation towards the focus of the lens, where a detector is placed. In particular, the INFN-LOGOS project aims at the realization of intrinsically bent silicon and germanium crystals exploiting the quasi-mosaic effect for focusing hard X-rays. Crystal manufacturing relies on a proper revisitation of techniques typically employed in silicon micromachining, such as thin film deposition and patterning or ion implantation.

  20. Analysis of mitochondrial mechanical dynamics using a confocal fluorescence microscope with a bent optical fibre.

    Science.gov (United States)

    Li, Yongbo; Honda, Satoshi; Iwami, Kentaro; Ohta, Yoshihiro; Umeda, Norihiro

    2015-11-01

    The cells in the cardiovascular system are constantly subjected to mechanical forces created by blood flow and the beating heart. The effect of forces on cells has been extensively investigated, but their effect on cellular organelles such as mitochondria remains unclear. We examined the impact of nano-Newton forces on mitochondria using a bent optical fibre (BOF) with a flat-ended tip (diameter exceeding 2 μm) and a confocal fluorescence microscope. By indenting a single mitochondrion with the BOF tip, we found that the mitochondrial elastic modulus was proportional to the (-1/2) power of the mitochondrial radius in the 9.6-115 kPa range. We stained the mitochondria with a potential-metric dye (TMRE) and measured the changes in TMRE fluorescence intensity. We confirmed that more active mitochondria exhibit a higher frequency of repetitive transient depolarization. The same trend was observed at forces lower than 50 nN. We further showed that the depolarization frequency of mitochondria decreases under an extremely large force (nearly 100 nN). We conclude that mitochondrial function is affected by physical environmental factors, such as external forces at the nano-Newton level.

  1. Record Deflection Efficiencies Measured for High Energy Protons in a Bent Germanium Crystal

    Science.gov (United States)

    Elsener, K.; Biino, C.; Clement, M.; Doble, N.; Gatignon, L.; Grafstrom, P.; Mikkelsen, U.; Kirsebom, K.; Møller, S. P.; Uggerhøj, E.; Worm, T.; Freund, A.

    1997-05-01

    New experimental results on the deflection of 450 GeV/c and 200 GeV/c protons in a bent Ge crystal are presented. At 450 GeV/c, the 50 mm long crystal gave record deflection efficiencies up to 60% for small angles (1 mrad), while at angles as large as 12 mrad, the efficiency is about 25 times larger than for a silicon crystal of the same size. Measurements up to 20 mrad deflection angle have been performed at 200 GeV/c as well as 450 GeV/c - the lower bending dechanneling leads to a rather slow decrease in efficiency at lower momenta, and 15% of the 200 GeV/c beam hitting the crystal are still deflected at the largest angles measured. These experimental results are in good agreement with a model for channeling deflection developed by Ellison and give confidence in extrapolations to higher energies (e.g. to LHC), other crystal materials or different deflection angles.

  2. Characterization of kink actuators as compared to traditional chevron shaped Bent-Beam electrothermal actuators

    KAUST Repository

    Rawashdeh, E.

    2012-07-06

    This paper compares the design and performance of kink actuators, a modified version of the bent-beam thermal actuator, to the standard chevron-shaped designs. A variety of kink and chevron actuator designs were fabricated from polysilicon. While the actuators were electrically probed, these designs were tested using a probe station connected to a National Instruments (NI) controller that uses LabVIEW to extract the displacement results via image processing. The displacement results were then used to validate the thermal-electric-structural simulations produced by COMSOL. These results, in turn, were used to extract the stiffness for both actuator types. The data extracted show that chevron actuators can have larger stiffness values with increasing offsets, but at the cost of lower amplification factors. In contrast, kink actuators showed a constant stiffness value equivalent to the chevron actuator with the highest amplification factor. The kink actuator also had larger amplification factors than chevrons at all designs tested. Therefore, kink actuators are capable of longer throws at lower power levels than the standard chevron designs.

  3. Variance reduction techniques for 14 MeV neutron streaming problem in rectangular annular bent duct

    Energy Technology Data Exchange (ETDEWEB)

    Ueki, Kotaro [Ship Research Inst., Mitaka, Tokyo (Japan)

    1998-03-01

    Monte Carlo method is the powerful technique for solving wide range of radiation transport problems. Its features are that it can solve the Boltzmann`s transport equation almost without approximation, and that the complexity of the systems to be treated rarely becomes a problem. However, the Monte Carlo calculation is always accompanied by statistical errors called variance. In shielding calculation, standard deviation or fractional standard deviation (FSD) is used frequently. The expression of the FSD is shown. Radiation shielding problems are roughly divided into transmission through deep layer and streaming problem. In the streaming problem, the large difference in the weight depending on the history of particles makes the FSD of Monte Carlo calculation worse. The streaming experiment in the 14 MeV neutron rectangular annular bent duct, which is the typical streaming bench mark experiment carried out of the OKTAVIAN of Osaka University, was analyzed by MCNP 4B, and the reduction of variance or FSD was attempted. The experimental system is shown. The analysis model by MCNP 4B, the input data and the results of analysis are reported, and the comparison with the experimental results was examined. (K.I.)

  4. X-ray Imaging of MagLIF Experiments Using a Spherically-Bent Crystal Optic

    Science.gov (United States)

    Harding, E. C.; Gomez, M. R.; Jennings, C. A.; Knapp, P. F.; Slutz, S. A.; Sefkow, A. B.; Awe, T. J.; Hansen, S. B.; Peterson, K. J.; Hahn, K. D.; McBride, R. D.; Rochau, G. A.; Sinars, D. B.; Golovkin, I.

    2015-11-01

    The recent Magnetized Liner Inertial Fusion (MagLIF) experiments performed on Sandia's Z-machine produced significant thermonuclear DD fusion yields that were accompanied by observable x-ray emission [M.R. Gomez et. al., PRL (2014)]. The MagLIF experiments relied on a spherically-bent crystal optic to image portions of the x-ray continuum that were generated by the hot stagnation plasma. The images of stagnation show a long (6 to 8 mm) and narrow (~100 micron) column of x-ray emission with structure in both directions. This structure may be caused by variations in the electron temperature (Te) and density (ne) , as well as opacity variations in the surrounding Be pusher. Here we investigate the possible contributions from each of these effects. We will also discuss the development of a diagnostic technique in which Te and ne of the DD fuel are inferred from spectra emitted by Fe impurities that become ionized to a He-like charge state. Sandia National Labs is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. DoE NNSA under contract DE-AC04-94AL85000.

  5. Energy loss distributions of relativistic protons axially channeled in a bent silicon crystal

    Science.gov (United States)

    Stojanov, Nace; Petrović, Srdjan; Nešković, Nebojša

    2013-05-01

    A detailed study of the energy loss distributions of the relativistic protons axially channeled in the bent Si crystals is presented in this work. The bending angle was varied from 0 to 20 μrad, while the crystal thickness was equal to 1 mm. The proton energy was chosen to be 7 TeV in accordance with the Large Hadron Collider (LHC) project, at the European Organization for Nuclear Research (CERN), in Geneva, Switzerland. The energy loss distributions of the channeled protons were generated using the numerical solution of the proton equations of motion in the transverse plane and the computer simulation method. An accurate energy loss model was used, which takes into account the trajectory dependence of the energy loss of protons during their motion through the crystal channels. Further, the dispersion of the proton's scattering angle caused by its collisions with the electrons of the crystal and the divergence of the proton beam were taken into account. The calculated dependence of the number of dechanneled protons on the bending angle was excellently fitted by the Gompertz type dechanneling function.

  6. Energy loss distributions of relativistic protons axially channeled in a bent silicon crystal

    Energy Technology Data Exchange (ETDEWEB)

    Stojanov, Nace, E-mail: nacestoj@pmf.ukim.mk [Institute of Physics, Faculty of Natural Sciences and Mathematics, Sts. Cyril and Methodius University, P.O. Box 162, 1000 Skopje (Macedonia, The Former Yugoslav Republic of); Petrović, Srdjan; Nešković, Nebojša [Laboratory of Physics (010), Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia)

    2013-05-01

    A detailed study of the energy loss distributions of the relativistic protons axially channeled in the bent < 100 > Si crystals is presented in this work. The bending angle was varied from 0 to 20 μrad, while the crystal thickness was equal to 1 mm. The proton energy was chosen to be 7 TeV in accordance with the Large Hadron Collider (LHC) project, at the European Organization for Nuclear Research (CERN), in Geneva, Switzerland. The energy loss distributions of the channeled protons were generated using the numerical solution of the proton equations of motion in the transverse plane and the computer simulation method. An accurate energy loss model was used, which takes into account the trajectory dependence of the energy loss of protons during their motion through the crystal channels. Further, the dispersion of the proton’s scattering angle caused by its collisions with the electrons of the crystal and the divergence of the proton beam were taken into account. The calculated dependence of the number of dechanneled protons on the bending angle was excellently fitted by the Gompertz type dechanneling function.

  7. New Results from the Solar Maximum Mission/Bent Crystal Spectrometer

    Science.gov (United States)

    Rapley, C. G.; Sylwester, J.; Phillips, K. J. H.

    2017-04-01

    The Bent Crystal Spectrometer (BCS) onboard the NASA Solar Maximum Mission was part of the X-ray Polychromator, which observed numerous flares and bright active regions from February to November 1980, when operation was suspended as a result of the failure of the spacecraft fine-pointing system. Observations resumed following the Space Shuttle SMM Repair Mission in April 1984 and continued until November 1989. BCS spectra have been widely used in the past to obtain temperatures, emission measures, and turbulent and bulk flows during flares, as well as element abundances. Instrumental details including calibration factors not previously published are given here, and the in-orbit performance of the BCS is evaluated. Some significant changes during the mission are described, and recommendations for future instrumentation are made. Using improved estimates for the instrument parameters and operational limits, it is now possible to obtain de-convolved calibrated spectra that show finer detail than before, providing the means for improved interpretation of the physics of the emitting plasmas. The results indicate how historical archived data can be re-used to obtain enhanced and new, scientifically valuable results.

  8. Standard practice for preparation and use of Bent-Beam stress-corrosion test specimens

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This practice covers procedures for designing, preparing, and using bent-beam stress-corrosion specimens. 1.2 Different specimen configurations are given for use with different product forms, such as sheet or plate. This practice applicable to specimens of any metal that are stressed to levels less than the elastic limit of the material, and therefore, the applied stress can be accurately calculated or measured (see Note 1). Stress calculations by this practice are not applicable to plastically stressed specimens. Note 1—It is the nature of these practices that only the applied stress can be calculated. Since stress-corrosion cracking is a function of the total stress, for critical applications and proper interpretation of results, the residual stress (before applying external stress) or the total elastic stress (after applying external stress) should be determined by appropriate nondestructive methods, such as X-ray diffraction (1). 1.3 Test procedures are given for stress-corrosion testing by ex...

  9. High resolution X-ray spherically bent crystal spectrometer for laser-produced plasma diagnostics

    Institute of Scientific and Technical Information of China (English)

    Shali Xiao; Hongjian Wang; Jun Shi; Changhuan Tang; Shenye Liu

    2009-01-01

    A new high spectral resolution crystal spectrometer is designed to measure very low emissive X-ray spectra of laser-produced plasma in 0.5 - 0.9 nm range. A large open aperture (30 x 20 (mm)) mica (002) spherically bent crystal with curvature radius R = 380 mm is used as dispersive and focusing element. The imaging plate is employed to obtain high spectral resolution with effective area of 30 x 80 (mm). The long designed path of the X-ray spectrometer beam is 980 mm from the source to the detector via the crystal. Experiment is carried out at a 20-J laser facility. X-ray spectra in an absolute intensity scale is obtained from Al laser produced plasmas created by laser energy of 6.78 J. Samples of spectra obtained with spectral resolution of up to E/鈻矱 ~ 1500 are presented. The results clearly show that the device is good to diagnose laser high-density plasmas.

  10. IMMEDIATE EFFECT OF NEURODYNAMIC SLIDING TECHNIQUE VERSUS MULLIGAN BENT LEG RAISE TECHNIQUE ON HAMSTRING FLEXIBILITY IN ASYMPTOMATIC INDIVIDUALS

    Directory of Open Access Journals (Sweden)

    Vinod Babu .K

    2015-08-01

    Full Text Available Background: Neurodynamics sliding technique (NDST and Mulligan bent leg raise technique (MBLR both have been individually advocated for increasing hamstring flexibility but comparison of these techniques have not been found in studies. The purpose of the study was to find immediate effect of neurodynamic sliding technique versus mulligan bent leg raise technique on hamstring flexibility in asymptomatic individuals. Methods: An Experimental study designs, with two group 80 asymptomatic normal subjects were randomized 40 subjects into each NDST group and MBLR group. NDST group received Neurodynamic sliding technique and MBLR group received Mulligan bent leg raise technique; passive straight leg raise was taken as outcome measure pre and post intervention. Results: When means of post intervention were compared there is statistically significant difference in means of passive SLR ROM within the groups but there is no statistically significant difference in post intervention means between the groups. Conclusion: It is concluded that both NDST and MBLR technique are effective on improving hamstring flexibility for asymptomatic individuals with limited SLR ROM. However there is no significant difference in improvement in hamstring flexibility between the groups.

  11. Detection of the X-ray spectra of imploding neon Z-pinch with elliptically bent mica crystal spectrometer

    Institute of Scientific and Technical Information of China (English)

    Jun Shi; Shali Xiao; Hongjian Wang; Xianbin Huang; Libing Yang; Shenye Liu

    2008-01-01

    A wide variety of X-ray and extreme ultraviolet diagnostics are being developed to study on Yang acceler- ator. An elliptically bent crystal spectrometer is designed with a focal length of 1350 mm. A mica crystal with an interplanar spacing of 1.984 nm bent onto an elliptical substrate with eccentricity of 0.9485 is used. The crystal analyzer covers the Bragg angle range from 30° to 60°. The mica crystal can efficiently reflect radiation in multiple orders, covering the entire spectral range from 0.1 to 1.73 nm except for a gap from 0.86 to 1.0 nm. The application experiment is performed on Yang accelerator using the bent mica crystal analyzer. Spectra of neon-puff Z-pinch plasmas are recorded with a X-ray film, showing the H-like and the He-like lines of neon. Each spectrum has been identified and used for the wavelength calibration, and most of the line radiation is contained in the He-α and the L-α lines. The experimental results have demonstrated that the spectral resolution approximates 379.

  12. Bent-Tailed Radio Sources in the Australia Telescope Large Area Survey of the Chandra Deep Field-South

    CERN Document Server

    Dehghan, Siamak; Franzen, Thomas M O; Norris, Ray P; Miller, Neal A

    2015-01-01

    Using the 1.4 GHz Australia Telescope Large Area Survey (ATLAS), supplemented with the 1.4 GHz Very Large Array images, we undertook a search for bent-tailed (BT) radio galaxies in the Chandra Deep Field-South (CDFS). Here we present a catalog of 56 detections, which include 45 bent-tailed sources, four diffuse low-surface-brightness objects (one relic, two halos, and one unclassified object), and a further seven complex, multi-component sources. We report BT sources with rest-frame powers in the range $10^{22} \\leq$ $\\textrm{P}_{1.4 \\textrm{ GHz}} \\leq 10^{26}$ W Hz$^{-1}$, redshifts up to 2 and linear extents from tens of kpc up to about one Mpc. This is the first systematic study of such sources down to such low powers and high redshifts and demonstrates the complementary nature of searches in deep, limited area surveys as compared to shallower, large surveys. Of the sources presented here one is the most distant bent-tailed source yet detected at a redshift of 2.1688. Two of the sources are found to be as...

  13. Chemical shifts assignments of the archaeal MC1 protein and a strongly bent 15 base pairs DNA duplex in complex.

    Science.gov (United States)

    Loth, Karine; Landon, Céline; Paquet, Françoise

    2015-04-01

    MC1 is the most abundant architectural protein present in Methanosarcina thermophila CHTI55 in laboratory growth conditions and is structurally unrelated to other DNA-binding proteins. MC1 functions are to shape and to protect DNA against thermal denaturation by binding to it. Therefore, MC1 has a strong affinity for any double-stranded DNA. However, it recognizes and preferentially binds to bent DNA, such as four-way junctions and negatively supercoiled DNA minicircles. Combining NMR data, electron microscopy data, biochemistry, molecular modelisation and docking approaches, we proposed recently a new type of DNA/protein complex, in which the monomeric protein MC1 binds on the concave side of a strongly bent 15 base pairs DNA. We present here the NMR chemical shifts assignments of each partner in the complex, (1)H (15)N MC1 protein and (1)H (13)C (15)N bent duplex DNA, as first step towards the first experimental 3D structure of this new type of DNA/protein complex.

  14. 弯晶X射线光学%Bent crystal X-ray optics

    Institute of Scientific and Technical Information of China (English)

    E Forster

    2007-01-01

    Much effort has been exerted both in the development of modern dedicated synchrotrons and free electron lasers with unique properties.Femtosecond laser plasma sources provide ultra-short X-ray pulses of high peak brilliance and can thus be complementary X-ray sources to the undulator based sources.All these modern X-ray sources need dedicated X-ray optics for diagnostics and applications,respectively.X-ray spectroscopy is one of the most important diagnostics of plasmas in the context of laser fusion.Depending on the aims of these experiments,monochromatic X-ray images or high resolution spectra combined with either spatial or time resolution can be obtained.Sophisticated monochromatic imagers with up to 10 toroidally bent crystals have been developed to study the implosion processes in laser fusion experiments;time-resolved maps of plasma parameters are evaluated from the data.High-power femtosecond lasers provide a practical,relatively inexpensive,powerful X-ray pulse source.Information on production efficiency,the energy distribution and transport of hot electrons is needed to maximize X-ray output in desired K-shell emission lines or continuum ranges so that peak brilliances comparable to those of synchrotrons may be feasible.Combining these new sources with bent crystal optics enables diffraction experiments on sub-picosecond time scales.Laser-pump X-rayprobe experiments have shown evidence of structure changes in several crystals within 250 fs.These X-ray optics have been designed in our institute using ray tracing and Bragg reflection codes for the 1D or 2D bent crystals or combinations thereof.In the preparation process,extreme care has been taken over crystal perfection,selection of optimum reflections,precision bending,measurement of imaging and reflection properties.X-ray topographic cameras and diffractometers are used to check the relevant properties of the analyzer crystals.%近年来,人们付出很大精力研制新的具有独特性能的同步辐

  15. Channeling, volume reflection and gamma emission using 14GeV electrons in bent silicon crystals - Oral presentation

    Energy Technology Data Exchange (ETDEWEB)

    Benson, Brandon [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-23

    High energy electrons can be deflected with very tight bending radius using a bent silicon crystal. This produces gamma radiation. As these crystals can be thin, a series of bent silicon crystals with alternating direction has the potential to produce coherent gamma radiation with reasonable energy of the driving electron beam. Such an electron crystal undulator offers the prospect for higher energy radiation at lower cost than current methods. Permanent magnetic undulators like LCLS at SLAC National Accelerator Laboratory are expensive and very large (about 100 m in case of the LCLS undulator). Silicon crystals are inexpensive and compact when compared to the large magnetic undulators. Additionally, such a high energy coherent light source could be used for probing through materials currently impenetrable by x-rays. In this work we present the experimental data and analysis of experiment T523 conducted at SLAC National Accelerator Laboratory. We collected the spectrum of gamma ray emission from 14 GeV electrons on a bent silicon crystal counting single photons. We also investigated the dynamics of electron motion in the crystal i.e. processes of channeling and volume reflection at 14 GeV, extending and building off previous work. Our single photon spectrum for the amorphous crystal orientation is consistent with bremsstrahlung radiation and the volume reflection crystal orientation shows a trend consistent with synchrotron radiation at a critical energy of 740 MeV. We observe that in these two cases the data are consistent, but we make no further claims because of statistical limitations. We also extended the known energy range of electron crystal dechanneling length and channeling efficiency to 14 GeV.

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

    Energy Technology Data Exchange (ETDEWEB)

    Martinson, Mercedes, E-mail: mercedes.m@usask.ca [University of Saskatchewan, 116 Science Place, Room 163, Saskatoon, Saskatchewan (Canada); Samadi, Nazanin [University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan (Canada); Belev, George [Canadian Light Source, 44 Innovation Boulevard, Saskatoon, Saskatchewan (Canada); Bassey, Bassey [University of Saskatchewan, 116 Science Place, Room 163, Saskatoon, Saskatchewan (Canada); Lewis, Rob [University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan (Canada); Monash University, Clayton, Victoria 3800 (Australia); Aulakh, Gurpreet [University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan (Canada); Chapman, Dean [University of Saskatchewan, 116 Science Place, Room 163, Saskatoon, Saskatchewan (Canada); University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan (Canada)

    2014-03-13

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

  17. High-efficiency deflection of high energy protons due to channeling along the axis of a bent silicon crystal

    Science.gov (United States)

    Scandale, W.; Arduini, G.; Butcher, M.; Cerutti, F.; Garattini, M.; Gilardoni, S.; Lechner, A.; Masi, A.; Mirarchi, D.; Montesano, S.; Redaelli, S.; Rossi, R.; Smirnov, G.; Breton, D.; Burmistrov, L.; Chaumat, V.; Dubos, S.; Maalmi, J.; Puill, V.; Stocchi, A.; Bagli, E.; Bandiera, L.; Germogli, G.; Guidi, V.; Mazzolari, A.; Dabagov, S.; Murtas, F.; Addesa, F.; Cavoto, G.; Iacoangeli, F.; Galluccio, F.; Afonin, A. G.; Chesnokov, Yu. A.; Durum, A. A.; Maisheev, V. A.; Sandomirskiy, Yu. E.; Yanovich, A. A.; Kovalenko, A. D.; Taratin, A. M.; Denisov, A. S.; Gavrikov, Yu. A.; Ivanov, Yu. M.; Lapina, L. P.; Malyarenko, L. G.; Skorobogatov, V. V.; James, T.; Hall, G.; Pesaresi, M.; Raymond, M.

    2016-09-01

    A deflection efficiency of about 61% was observed for 400 GeV/c protons due to channeling, most strongly along the axis of a bent silicon crystal. It is comparable with the deflection efficiency in planar channeling and considerably larger than in the case of the axis. The measured probability of inelastic nuclear interactions of protons in channeling along the axis is only about 10% of its amorphous level whereas in channeling along the (110) planes it is about 25%. High efficiency deflection and small beam losses make this axial orientation of a silicon crystal a useful tool for the beam steering of high energy charged particles.

  18. 磨剑,岂止十年?——访挪威Hegel主设计师Bent Holter

    Institute of Scientific and Technical Information of China (English)

    沈剑萍

    2009-01-01

    在2008年的白天鹅音响展上,我再次与Hegel(音响哲学)的创始人Bent Holter(以下简称作Bent)。在这次展会上,Bent带来了Hegel最新型号P10/H10十周年纪念版前后级放大器。笔者就此对他进行了简短的采谎

  19. 新品层出不穷 访挪威Hegel主设计师Bent Holter

    Institute of Scientific and Technical Information of China (English)

    沈剑萍

    2010-01-01

    在2009年的白天鹅音响展上,我再次与Hegel(音响哲学)的创始人Bent Holter(以下简称Bent)相遇。在这次展会上,Bent兴致很高,原来是2009年Hegel的销售又创出了新纪录,而且刚推出的新型号也获到了广泛的好评。笔者趁此机会对他进行了简短的采访。

  20. Extraction of 22 TeV/c Lead Ions from the CERN SPS using a Bent Silicon Crystal

    Science.gov (United States)

    Herr, W.; Elsener, K.; Fidecaro, G.; Gyr, M.; Klem, J.; Weisse, E.

    1997-05-01

    The extraction of protons from the halo of a circulating beam has been repeatedly demonstrated at the SPS. In a recent experiment a coasting lead ion beam was available at a momentum of 270 GeV/c/Z corresponding to a total momentum of 22 TeV/c per ion and the possibility to extract ultrarelativistic lead ions with a bent crystal could be demonstrated for the first time. We present the experimental challenges, the measurements performed during this experiment and the first results.

  1. Observation of focusing of 400 GeV/c proton beam with the help of bent crystals

    CERN Document Server

    Scandale, W; Butcher, M; Cerutti, F; Gilardoni, S; Lechner, A; Losito, R; Masi, A; Metral, E; Mirarchi, D; Montesano, S; Redaelli, S; Smirnov, G; Bandiera, L; Baricordi, S; Dalpiaz, P; Guidi, V; Mazzolari, A; Vincenzi, D; Claps, G; Dabagov, S; Hampai, D; Murtas, F; Cavoto, G; Garattini, M; Iacoangeli, F; Ludovici, L; Santacesaria, R; Valente, P; Galluccio, F; Afonin, A G; Chesnokov, Yu A; Chirkov, P N; Maisheev, V A; Sandomirskiy, Yu E; Yazynin, I A; Kovalenko, A D; Taratin, A M; Gavrikov, Yu A; Ivanov, Yu M; Lapina, L P; Ferguson, W; Fulcher, J; Hall, G; Pesaresi, M; Raymond, M

    2014-01-01

    The results of observation and studies of focusing of 400 GeV/c proton beam with the help of bent single crystals are presented. Two silicon crystals have been used in the measurements. The focal length of the first and second crystals is found to be 1.48 m and 0.68 m, respectively. The mean square size of the horizontal profile in the focus was 3.1 and 4.3 times as small as at the exit of the crystals.

  2. Enhanced Fracture Resistance of Flexible ZnO:Al Thin Films in Situ Sputtered on Bent Polymer Substrates.

    Science.gov (United States)

    Choi, Hong Rak; Eswaran, Senthil Kumar; Lee, Seung Min; Cho, Yong Soo

    2015-08-19

    Improving the fracture resistance of inorganic thin films is one of the key challenges in flexible electronic devices. A nonconventional in situ sputtering method is introduced to induce residual compressive stress in ZnO:Al thin films during deposition on a bent polymer substrate. The films grown under a larger prebending strain resulted in a higher fracture resistance to applied strains by exhibiting a ∼ 70% improvement in crack-initiating critical strain compared with the reference sample grown without bending. This significant improvement is attributed to the induced residual stress, which helps to prevent the formation of cracks by counteracting the applied strain.

  3. Dielectric technique to measure the twist elastic constant of liquid crystals: the case of a bent-core material.

    Science.gov (United States)

    Salamon, P; Eber, N; Seltmann, J; Lehmann, M; Gleeson, J T; Sprunt, S; Jákli, A

    2012-06-01

    The effect of director pretilt on the twist magnetic Fréedericksz transition of nematics was investigated in a planar cell. The director configuration was calculated as a function of magnetic inductance. The dielectric and optical response of the nematic liquid crystal was numerically modeled. A dielectric measurement method for determining the elastic constant K_{22} is presented. The influence of the conditions for the Mauguin effect is discussed. The theoretical predictions were confirmed by our experiments. Experimental data for all elastic constants of a bent-core nematic material are presented and discussed.

  4. The crucial role of the f electrons in the bent or linear configuration of uranium cyanido metallocenes

    Energy Technology Data Exchange (ETDEWEB)

    Maynadie, J.; Berthet, J.C.; Thuery, P.; Ephritikhine, M. [Service de Chimie Moleculaire, DSM, DRECAM, CNRS URA 331, CEA/Saclay 91191 Gif sur Yvette cedex (France); Maron, L. [Laboratoire de Nanophysique Magnetisme et Optoelectronique, INSA Universite Paul Sabatier, 135 avenue de Rangueil, 31077 Toulouse cedex (France); Barros, N. [Service de Chimie des Procedes de Separation, DEN, DRCP, CEA Valrho BP 17171, 30207 Bagnols sur Ceze (France)

    2007-03-04

    Here is reported on the U{sup III}-U{sup V} complexes [Cp{sup *}{sub 2}U(CN){sub 3}][NR{sub 4}]{sub n} (n=1,2) and [Cp{sup *}{sub 2}U(CN){sub 5}][NR{sub 4}]{sub n} (n=2,3), which adopt a bent and linear configuration, respectively. These results raise the fundamental question of the nature of the metal-ligand interaction and the influence of the number of f electrons on the geometry of the complexes. The crucial role of the f orbitals is evidenced by density functional theory (DFT) analysis. (O.M.)

  5. Magnetic cloud models with bent and oblate cross-section boundaries

    Science.gov (United States)

    Démoulin, P.; Dasso, S.

    2009-11-01

    Context: Magnetic clouds (MCs) are formed by magnetic flux ropes that are ejected from the Sun as coronal mass ejections. These structures generally have low plasma beta and travel through the interplanetary medium interacting with the surrounding solar wind. Thus, the dynamical evolution of the internal magnetic structure of a MC is a consequence of both the conditions of its environment and of its own dynamical laws, which are mainly dominated by magnetic forces. Aims: With in-situ observations the magnetic field is only measured along the trajectory of the spacecraft across the MC. Therefore, a magnetic model is needed to reconstruct the magnetic configuration of the encountered MC. The main aim of the present work is to extend the widely used cylindrical model to arbitrary cross-section shapes. Methods: The flux rope boundary is parametrized to account for a broad range of shapes. Then, the internal structure of the flux rope is computed by expressing the magnetic field as a series of modes of a linear force-free field. Results: We analyze the magnetic field profile along straight cuts through the flux rope, in order to simulate the spacecraft crossing through a MC. We find that the magnetic field orientation is only weakly affected by the shape of the MC boundary. Therefore, the MC axis can approximately be found by the typical methods previously used (e.g., minimum variance). The boundary shape affects the magnetic field strength most. The measurement of how much the field strength peaks along the crossing provides an estimation of the aspect ratio of the flux-rope cross-section. The asymmetry of the field strength between the front and the back of the MC, after correcting for the time evolution (i.e., its aging during the observation of the MC), provides an estimation of the cross-section global bending. A flat or/and bent cross-section requires a large anisotropy of the total pressure imposed at the MC boundary by the surrounding medium. Conclusions: The

  6. The influence of the dechanneling process on the photon emission by an ultra-relativistc positron channeling in a periodically bent crystal

    CERN Document Server

    Korol, A V; Greiner, W

    2001-01-01

    We investigate, both analytically and numerically, the influence of the dechanneling process on the parameters of undulator radiation generated by ultra-relativistic positron channelling along a crystal plane, which is periodically bent. The bending might be due either to the propagation of a transverse acoustic wave through the crystal, or due to the static strain as it occurs in superlattices. In either case the periodically bent crystal serves as an undulator which allows to generate X-ray and gamma-radiation. We propose the scheme for accurate quantitative treatment of the radiation in presence of the dechanneling. The scheme includes (i) the analytic expression for spectral-angular distribution which contains, as a parameter, the dechanneling length, (ii) the simulation procedure of the dechanneling process of a positron in periodically bent crystals. Using these we calculate the dechanneling lengths of 5 GeV positrons channeling in Si, Ge and W crystals, and the spectral-angular and spectral distributio...

  7. Molecular arrangement in Langmuir and Langmuir-Blodgett films of a mesogenic bent-core carboxylic acid.

    Science.gov (United States)

    Giner, Ignacio; Gascón, Ignacio; Vergara, Jorge; López, M Carmen; Ros, M Blanca; Royo, Félix M

    2009-10-20

    A different alternative to previous research on Langmuir and Langmuir-Blodgett (LB) films of bent-core liquid crystals is reported in this work. A bent-shaped molecule wearing a terminal carboxylic group has been used to obtain monomolecular films with their long molecular axis almost perpendicular to the aqueous surface. Langmuir films at the air-liquid interface (pH=9) have been characterized by a combination of surface pressure and surface potential versus area per molecule isotherms, Brewster angle microscopy, and ultraviolet reflection spectroscopy. A condensed phase is reached at surface pressures up to 20 mN x m-1. In this condensed phase, molecules are packed forming H-aggregates with a well-defined molecular orientation. Langmuir films have been transferred onto quartz and silicon substrates and characterized by means of UV-vis spectroscopy and XRR. The transference is Z-type, with a constant deposition of the monolayers. The total LB monolayer film thickness is evaluated to be about 5.8 nm, which is in good agreement with the deduced orientation at the air-liquid interface as well as with the lamellar order observed within the solid obtained by cooling the sample from the mesophase.

  8. Dielectric and electro-optic studies of a bimesogenic liquid crystal composed of bent-core and calamitic units.

    Science.gov (United States)

    Balachandran, R; Panov, V P; Vij, J K; Shanker, G; Tschierske, C; Merkel, K; Kocot, A

    2014-09-01

    A bimesogen, BR1, composed of a bent-core and calamitic unit, linked laterally via a flexible spacer is investigated by dielectric and electro-optic techniques. X-ray results show the presence of clusters in the nematic phase, and the cluster size is of the order of the thickness of a single layer. The splitting of the small-angle scattering Δχ/2 is about 50°, which indicates SmC like clusters with a significant tilt of the molecules in the quasilayers. The sign reversal of the dielectric anisotropy Δε' is observed as a function of frequency; the behavior is rather similar to that exhibited by the conventional dual frequency nematics, composed of a calamitic mesogen, with the exception that it occurs at much lower frequencies in this material. Interestingly, as the bimesogen enters its nematic phase, the average permittivity decreases as the temperature is lowered. This indicates the onset of antiparallel association of some of the dipoles in the system, and this type of association is much more prominent in BR1 in comparison to other bent-core liquid crystalline systems composed of the same bisbenzoate core unit. The analysis of the dielectric spectra using the Maier-Meier model confirms the onset of an antiparallel correlation of dipoles occurring at the isotropic to nematic phase transition temperature. Additionally these results support a model of the cluster where the transverse dipole moments in the neighboring layers are antiparalleled to each other.

  9. Distribuição horizontal da macrofauna bentônica na praia do Cassino, extremo sul do Brasil

    Directory of Open Access Journals (Sweden)

    Luciano Peyrer das Neves

    2012-09-01

    Full Text Available A distribuição horizontal da macrofauna bentônica na praia do Cassino, Rio Grande do Sul, Brasil foi estudada durante o período de um ano (junho 2004 a maio de 2005 com base em coletas mensais. Foram escolhidos três locais, com 50 m de distância um do outro, sendo que em cada local foram fundeadas três transversais 2 m equidistantes. Cada transversal estendeu-se da base das dunas primárias até aproximadamente 1 m de profundidade no infralitoral. A distância dos níveis de coleta em cada transversal foi de 20 m até o limite superior da zona de varrido, a partir do qual a distância foi de 10 m. Em algumas ocasiões foi evidenciada variação espacial horizontal de alguns dos principais táxons, bem como da comunidade bentônica dentro de uma escala de 50 m e 100 m. Esta variação foi provavelmente reflexo da ação das marés meteorológicas que causam abrupta elevação do nível do mar.

  10. On the reduced interaction probability for fully stripped 33 TeV/c Pb ions channeled in a bent Si crystal

    Science.gov (United States)

    Biino, C.; Clément, M.; Doble, N.; Elsener, K.; Freund, A.; Gatignon, L.; Grafström, P.; Herr, W.; Taratin, A.; Uggerhøj, U. I.; Uzhinskii, V. V.; Velasco, M.

    2002-10-01

    We compare experimental results and computer simulations on the reduction of inelastic interactions for 33 TeV Pb 82+ ions channeled in a bent silicon crystal. The comparison shows that a very small fraction of the initially channeled ions suffer nuclear interactions while traversing the 60 mm long crystal under perfect alignment, even though its thickness would correspond to about 1.2 nuclear interaction lengths for an amorphous material. This result indicates that a bent crystal approach to extraction of high energy, fully stripped ions from e.g. RHIC or LHC might be feasible.

  11. On the reduced interaction probability for fully stripped 33 TeV/c Pb ions channeled in a bent Si crystal

    Energy Technology Data Exchange (ETDEWEB)

    Biino, C.; Clement, M.; Doble, N.; Elsener, K.; Freund, A.; Gatignon, L.; Grafstroem, P.; Herr, W.; Taratin, A.; Uggerhoej, U.I. E-mail: ulrik@ifa.au.dk; Uzhinskii, V.V.; Velasco, M

    2002-10-01

    We compare experimental results and computer simulations on the reduction of inelastic interactions for 33 TeV Pb{sup 82+} ions channeled in a bent silicon crystal. The comparison shows that a very small fraction of the initially channeled ions suffer nuclear interactions while traversing the 60 mm long crystal under perfect alignment, even though its thickness would correspond to about 1.2 nuclear interaction lengths for an amorphous material. This result indicates that a bent crystal approach to extraction of high energy, fully stripped ions from e.g. RHIC or LHC might be feasible.

  12. On the reduced interaction probability for fully stripped 33 TeV/c Pb ions channeled in a bent Si crystal

    CERN Document Server

    Uggerhøj, U; Clément, M; Doble, Niels T; Elsener, K; Freund, A; Gatignon, L; Grafström, P; Herr, Werner; Taratin, A; Uzhinskii, V V; Velasco, M

    2002-01-01

    We compare experimental results and computer simulations on the reduction of inelastic interactions for 33 TeV Pb**8**2**+ ions channeled in a bent silicon crystal. The comparison shows that a very small fraction of the initially channeled ions suffer nuclear interactions while traversing the 60 mm long crystal under perfect alignment, even though its thickness would correspond to about 1.2 nuclear interaction lengths for an amorphous material. This result indicates that a bent crystal approach to extraction of high energy, fully stripped ions from e.g. RHIC or LHC might be feasible.

  13. Alternating twist structures formed by electroconvection in the nematic phase of an achiral bent-core molecule.

    Science.gov (United States)

    Tanaka, Shingo; Dhara, Surajit; Sadashiva, B K; Shimbo, Yoshio; Takanishi, Yoichi; Araoka, Fumito; Ishikawa, Ken; Takezoe, Hideo

    2008-04-01

    We report an unusual electroconvection in the nematic phase of a bent-core liquid crystal. In a voltage-frequency diagram, two frequency regions exhibiting prewavy stripe patterns were found, as reported by Wiant We found that these stripes never show extinction dark when cells were rotated under crossed polarizers. Based on the color interchange in between neighboring stripes by the rotation of the cells or an analyzer, twisted molecular orientation is suggested; i.e., the directors are alternately twisted from the top to the bottom surfaces with a pretilt angle in adjacent stripes, which is an analogue of the twisted (splayed) structure observed in surface-stabilized ferroelectric liquid crystal cells. The transmittance spectra calculated using the 4x4 matrix method from the model structure are consistent with the experimental observation.

  14. Breakdown of Shape Memory Effect in Bent Cu-Al-Ni Nanopillars: When Twin Boundaries Become Stacking Faults.

    Science.gov (United States)

    Liu, Lifeng; Ding, Xiangdong; Sun, Jun; Li, Suzhi; Salje, Ekhard K H

    2016-01-13

    Bent Cu-Al-Ni nanopillars (diameters 90-750 nm) show a shape memory effect, SME, for diameters D > 300 nm. The SME and the associated twinning are located in a small deformed section of the nanopillar. Thick nanopillars (D > 300 nm) transform to austenite under heating, including the deformed region. Thin nanopillars (D < 130 nm) do not twin but generate highly disordered sequences of stacking faults in the deformed region. No SME occurs and heating converts only the undeformed regions into austenite. The defect-rich, deformed region remains in the martensite phase even after prolonged heating in the stability field of austenite. A complex mixture of twins and stacking faults was found for diameters 130 nm < D < 300 nm. The size effect of the SME in Cu-Al-Ni nanopillars consists of an approximately linear reduction of the SME between 300 and 130 nm when the SME completely vanishes for smaller diameters.

  15. Generation of CW cold CH3CN molecular beam by a bent electostatic quadrupole guiding: Monte-Carlo study

    Institute of Scientific and Technical Information of China (English)

    Min YUN; Yang LIU; Lian-zhong DENG; Qi ZHOU; Jian-ping YIN

    2008-01-01

    A new kind of continuous-wave (CW) cold mo-lecular beam, methyl cyanide (CH3 CN) beam, is generated by a bent electrostatic quadrupole guiding. The Stark shift of rotational energy levels of CH,3CN molecule and its popula-tion distribution are calculated, and the dynamic processes of electrostatic guiding and energy filtering of CH3CN molecules from a gas source with room temperature (300 K) are simu-lated by Monte Carlo Method. The study showed that the lon-gitudinal and transversal temperatures of output cold CH,3CN beam could be about -2 K and-420 mK, and the corre-sponding guiding efficiency was about 10'-5 as the guiding voltage was 3 kV. Furthermore, the temperature of the guided molecules and its guiding efficiency can be controlled by ad-justing the guiding voltages applied on electrodes.

  16. Structural Diversity of Metallosupramolecular Assemblies Based on the Bent Bridging Ligand 4,4′-Dithiodipyridine

    Directory of Open Access Journals (Sweden)

    Rüdiger W. Seidel

    2013-05-01

    Full Text Available 4,4′-Dithiodipyridine (dtdp, also termed 4,4′-dipyridyldisulfide, is a bridging ligand of the 4,4′-bipyridine type. The introduction of the disulfide moiety inevitably leads to a relatively rigid angular structure, which exhibits axial chirality. More than 90 metal complexes containing the dtdp ligand have been crystallographically characterised until now. This review focuses on the preparation and structural diversity of discrete and polymeric metallosupramolecular assemblies constructed from dtdp as bridging ligands. These encompass metallamacrocycles with M2L2 topology and coordination polymers with periodicity in one or two dimensions. One-dimensional coordination polymers represent the vast majority of the metallosupramolecular structures obtained from dtdp. These include repeated rhomboids, zigzag, helical and arched chains among other types. In this contribution, we make an attempt to provide a comprehensive account of the structural data that are currently available for metallosupramolecular assemblies based on the bent bridging ligand dtdp.

  17. The Diet and Sexual Differences of the Caspian Bent-Toed Gecko, Tenuidactylus caspius (Squamata: Gekkonidae, in Northern Iran

    Directory of Open Access Journals (Sweden)

    Vida Hojati

    2014-01-01

    Full Text Available The Caspian bent-toed gecko, Tenuidactylus caspius, is one of the most common nocturnal lizards of Iran with widespread distribution especially in the northern provinces. This research was done in order to study the diet and sexual dimorphism of this species in Sari County from 5 May to 20 October. During this research, 40 specimens of them including 20 males and 20 females were studied for diet and 140 specimens including 70 adult males and 70 adult females were studied for sexual dimorphism. Prey items identified were insects that belong to 15 species of 8 families and 6 orders. The most common prey items were Culex pipiens and Musca domestica. There is no significant difference between diets of males and females. Results show that the adult males in addition of having the apparent femoral and preanal pores are heavier than females and have larger body, head, and tail length.

  18. Evaluation of Contact Friction in Fracture of Rotationally Bent Nitinol Endodontic Files

    Science.gov (United States)

    Haimed, Tariq Abu

    2011-12-01

    The high flexibility of rotary Nitinol (Ni-Ti) files has helped clinicians perform root canal treatments with fewer technical errors than seen with stainless steel files. However, intracanal file fracture can occur, compromising the outcome of the treatment. Ni-Ti file fracture incidence is roughly around 4% amongst specialists and higher amongst general practitioners. Therefore, eliminating or reducing this problem should improve patient care. The aim of this project was to isolate and examine the role of friction between files and the canal walls of the glass tube model, and bending-related maximum strain amplitudes, on Ni-Ti file lifetimes-tofracture in the presence of different irrigant solutions and file coatings. A specifically designed device was used to test over 300 electropolished EndoSequenceRTM Ni-Ti files for number of cycles to failure (NCF) in smooth, bent glass tube models at 45 and 60 degrees during dry, coated and liquid-lubricated rotation at 600rpm. Fractured files were examined under Scanning Electron Microscopy (SEM) afterwards. Four different file sizes 25.04, 25.06, 35.04, 35.06 (diameter in mm/taper %) and six surface modification conditions were used independently. These conditions included, three solutions; (1) a surfactant-based solution, Surface-Active-Displacement-Solution (SADS), (2) a mouth wash proven to remove biofilms, Delmopinol 1%(DEL), and (3) Bleach 6% (vol.%), the most common antibacterial endodontic irrigant solution. The conditions also included two low-friction silane-based coating groups, 3-Hepta-fluoroisopropyl-propoxymethyl-dichlorosilane (3-HEPT) and Octadecyltrichlorosilane (ODS), in addition to an as-received file control group (Dry). The coefficient of friction (CF) between the file and the canal walls for each condition was measured as well as the surface tension of the irrigant solutions and the critical surface tension of the coated and uncoated files by contact angle measurements. The radius of curvature and

  19. Acoplamiento pelágico-bentónico: respuesta de la zona bentónica profunda a la sedimentación del florecimiento invernal de diatomeas en el lago oligotrófico Alchichica, Puebla, México Pelagic-benthic coupling: deep benthic zone response to winter diatom bloom sinking in oligotrophic Lake Alchichica, Puebla, Mexico

    OpenAIRE

    Javier Alcocer; Elva Escobar; Luis A. Oseguera

    2008-01-01

    El objetivo del presente estudio es reconocer la existencia de un acoplamiento pelágico-bentónico en el lago oligotrófico tropical Alchichica evaluando la respuesta de la zona bentónica profunda a la sedimentación del florecimiento invernal de diatomeas. Se midió la biomasa fitoplanctónica en la columna de agua a lo largo de un ciclo anual, al igual que la concentración de clorofila a sedimentaria. Alchichica es un lago monomíctico cálido con un periodo de circulación invernal y estratificaci...

  20. Bent and Generalized Bent Boolean Functions

    Science.gov (United States)

    2012-01-01

    from Zn2 to Z2. Then the crosscorrelation between f and g at u ∈ Zn2 is C f,g(u) = 1 2 ( Cb1 ,b2(u)+ Ca1+b1,a2+b2(u) )+ ı 2 ( Cb1 ,a2+b2(u)− Ca1+b1,b2(u...x⊕u) = 1 2 ( Cb1 ,b2(u)+ Ca1+b1,a2+b2(u) )+ ı 2 ( Cb1 ,a2+b2(u)− Ca1+b1,b2(u) ) . (20) which follows directly from the formula ıa−b = 1+(−1)a+b2 + (−1

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

    Directory of Open Access Journals (Sweden)

    María Custodio Villanueva

    2016-01-01

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

  2. Microperfurações em Foraminíferos Bentônicos da Lagoa Pitanguinha, RJ.

    Directory of Open Access Journals (Sweden)

    Mariana Cardoso

    2007-07-01

    Full Text Available Os foraminíferos bentônicos têm sido foco deestudos paleoecológicos por serem geralmente abundantese possuírem bom potencial de preservaçãodevido à carapaça de composição calcárea ou aglutinada.São indicadores potenciais do ambiente, e seuestado de preservação é um reflexo direto de fatoresambientais, entre eles, a atividade bioerosiva. Os organismosperfuradores são os principais agentes debioerosão em ambiente carbonático, comprometendoa preservação dos esqueletos. A lagoa Pitanguinhafaz parte do complexo lagunar em Araruama, noEstado do Rio de Janeiro, juntamente com outraslagunas distribuídas ao longo de uma estreita planície.Localizada na restinga de Massambaba, entreas latitudes 22°55’42’’ e 22°56’00’’S e longitudes42°20’45’’ e 42°2°21’30’’W, tem sua formação relacionadaa duas transgressões marinhas sucessivas.O presente estudo tem por objetivo registrar traçosde bioerosão em foraminíferos bentônicos da LagoaPitanguinha, Rio de Janeiro. Das amostras cedidaspara estudo pelo LABIOTAL/Ecb/UNIRIO, foramretirados 50 cm3 de sedimento, lavados em água correnteempregando-se peneiras 53, 75 e 212 mesh,desidratados em temperatura ambiente e triadas paraa identificação dos foraminíferos e das microperfurações,sendo analisado um total de 100 indivíduos.A identificação dos foraminíferos empregou microscópioestereoscópico e as fotomicrografias paraobservação bioerosão nas carapaças foram obtidasem microscópio eletrônico de varredura. As associaçõesde foraminíferos bentônicos são compostaspelas espécies de carapaças hialinas Ammoniatepida, Discorbis sp. e as espécies de carapaçasporcelanosas foram Quinqueloculina laevigata,Quinqueloculina poeyana, Quinqueloculina seminulum,Quinqueloculina sp., Triloculina oblonga eTriloculina sp. A. tepida e Q. laevigata aparecemcom maior freqüência e maiores índices de microbioerosão.Nas espécies porcelanosas, as perfura

  3. Observation of high deflection efficiency and narrow energy loss distributions for 450 GeV protons channeled in a bent silicon crystal

    Science.gov (United States)

    Møller, S. P.; Worm, T.; Clément, M.; Doble, N.; Elsener, K.; Gatignon, L.; Grafström, P.; Uggerhøj, E.; Hage-Ali, M.; Siffert, P.

    1994-03-01

    A 450 GeV proton beam has been deflected by various angles from 1 to 11 mrad using planar channeling in a (111) silicon crystal which was mechanically bent to achieve the desired beam deflection. High deflection efficiencies of up to 50% have been measured, in good agreement with present theoretical estimates. It is shown that bent crystals are also a unique tool for measurements of energy loss and straggling of channeled particles, without any influence from random particles: Selecting protons which are deflected by increasing angles corresponds to decreasing the transverse energy at the crystal entrance. With this technique energy loss and straggling was measured for protons channeled in the wide and narrow (111) planes in silicon for the first time.

  4. Deflection of high-energy negative particles in a bent crystal through axial channeling and multiple volume reflection stimulated by doughnut scattering

    CERN Document Server

    Taratin, AM; Chesnokov, Yu A; Denisov, A S; Dalpiaz, P; Bagli, E; Taratin, A M; Lapina, L P; Vavilov, S A; Fiorini, M; Vallazza, E; Afonin, A G; Guidi, V; Baricordi, S; Prest, M; Kovalenko, A D; Skorobogatov, V V; Scandale, W; Golovatyukh, V M; Suvorov, V M; Maisheev, V A; Vincenzi, D; Ivanov, Yu M; Hasan, S; Bolognini, D; Yazynin, I A; Della Mea, Gianantonio; Mazzolari, A; Gavrikov, Yu A; Vomiero, A; Milan, R

    2010-01-01

    Different kinds of deflection in a silicon crystal bent along the (111) axis was observed for 150 GeV/c negative particles. mainly pi(-) mesons, at one of the secondary beams of the CERN SPS. The whole beam was deflected to one side in quasi-bound states of doughnut scattering (DSB) by atomic strings with the efficiency (95.4 +/- 0.2)\\% and with the peak position close to the bend crystal angle, alpha = 185 mu rad. It was observed volume capture of pi(-) mesons into the DSB states with a probability higher than 7\\%. A beam deflection opposite to the crystal bend was observed for some orientations of the crystal axis due to doughnut scattering and subsequent multiple volume reflections of pi(-) mesons by different bent planes crossing the axis. (C) 2010 Elsevier B.V. All rights reserved.

  5. Investigation of supramolecular architectures of bent-shaped pyridine derivatives: from a three-ring crystalline compound towards five-ring mesogens

    CERN Document Server

    Trišović, Nemanja; Rogan, Jelena; Poleti, Dejan; Tóth-Katona, Tibor; Salamonczyk, Miroslaw; Jákli, Antal; Fodor-Csorba, Katalin

    2016-01-01

    In searching for novel photoactive liquid crystals, we have synthesized a series of five-ring pyridine-based bent-core compounds bearing different substituents at the peripheral phenyl rings (CH3O, Cl and NO2). Their mesomorphic behaviour has been investigated by polarizing optical microscopy, differential scanning calorimetry and X-ray scattering, and then compared with the unsubstituted parent compound. The introduction of the methoxy groups at the peripheral phenyl rings of the bent core results in a non-mesomorphic compound, whereas the chloro- and nitro-substituted compounds form enantiotropic B1-like phases. Significant changes of the textures and transition temperatures of the mesophase have been observed under UV light. The presented investigation of the mesomorphic properties of the synthesized compounds, coupled with analysis of the molecular packing of the related three-ring compounds, will help to design self-organized molecules suitable for UV indicators.

  6. Effect of small variations in the refractive index of the ambient medium on the spectrum of a bent fibre-optic Fabry - Perot interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Kulchin, Yurii N; Vitrik, O B; Gurbatov, S O [Institute for Automation and Control Processes, Far-Eastern Branch, Russian Academy of Sciences, Vladivostok (Russian Federation)

    2011-09-30

    The phase of light propagating through a bent optical fibre is shown to depend on the refractive index of the medium surrounding the fibre cladding when there is resonance coupling between the guided core mode and cladding modes. This shifts the spectral maxima in the bent fibre-optic Fabry - Perot interferometer. The highest phase and spectral sensitivities achieved with this interferometer configuration are 0.71 and 0.077, respectively, and enable changes in the refractive index of the ambient medium down to 5 Multiplication-Sign 10{sup -6} to be detected. This makes the proposed approach potentially attractive for producing highly stable, precision refractive index sensors capable of solving a wide range of liquid refractometry problems.

  7. Development of resistance of Apera spica-venti (L. P. Beauv. (Loose silky-bent in Lower Saxony in 2013 - also increasingly against Pinoxaden

    Directory of Open Access Journals (Sweden)

    Wolber, Dirk Michael

    2014-02-01

    Full Text Available Herbicide resistance has increased dramatically all over the world. Especially North America, South America and Australia are affected. In the last few years also in Europe different active ingredient groups become more and more ineffectively. The risk of resistance is very high for the ACC-ase inhibitors (Group A, the photosynthese- inhibitors (Group C and by now also for the ALS - inhibitors (Group B. In almost every agricultural region of Lower Saxony the loose silky-bent grass (Apera spica-venti shows resistance to at least one mode of action. Since 2005 especially in the lower saxonian region between Osnabrück, Hannover and Braunschweig resistance in loose silky-bent grass against the ALS- inhibitors occurs. 2012 target site resistance against Pinoxaden was found for the first time. In the last few years also in Europe different active ingredient groups became more and more ineffectively.

  8. High energy-resolution x-ray spectroscopy at ultra-high dilution with spherically bent crystal analyzers of 0.5 m radius

    CERN Document Server

    Rovezzi, Mauro; Manceau, Alain; Glatzel, Pieter; Verbeni, Roberto

    2016-01-01

    We present the development, manufacturing and performance of spherically bent crystal analyzers (SBCAs) of 100 mm diameter and 0.5 m bending radius. The elastic strain in the crystal wafer is partially released by a "strip-bent" method where the crystal wafer is cut in strips prior to the anodic bonding process. Compared to standard 1 m SBCAs, a gain in intensity is obtained without loss of energy resolution. The gain ranges between 2.5 and 7, depending on the experimental conditions and the width of the emission line measured. This reduces the acquisition times required to perform high energy-resolution x-ray absorption and emission spectroscopy on ultra-dilute species, accessing concentrations of the element of interest down to, or below, the ppm (ng/mg) level.

  9. Temperature profiles from expendable bathythermograph (XBT) casts from the USNS SILAS BENT in the North Pacific Ocean in support of the Integrated Global Ocean Services System (IGOSS) project from 04 March 1977 to 27 March 1977 (NODC Accession 7700351)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — XBT data were collected from the USNS SILAS BENT in support of the Integrated Global Ocean Services System (IGOSS) project. Data were collected by the US Navy; Naval...

  10. Benthic organism and other data from the Gulf of Alaska from the USNS SILAS BENT as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 31 August 1975 to 14 September 1975 (NODC Accession 7700434)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Benthic organism and other data were collected in the Gulf of Alaska from the USNS SILAS BENT by University of Alaska; Institute of Marine Science (UAK/IMS). Data...

  11. Temperature profiles from expendable bathythermograph (XBT) casts from the USNS SILAS BENT in the North Pacific Ocean in support of the Integrated Global Ocean Services System (IGOSS) project from 24 April 1977 to 27 April 1977 (NODC Accession 7700487)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — XBT data were collected from the USNS SILAS BENT in support of the Integrated Global Ocean Services System (IGOSS) project. Data were collected by the US Navy;...

  12. Temperature and salinity profiles from STD casts in the Bering Sea from the SILAS BENT as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 01 September 1975 to 26 September 1975 (NODC Accession 7600747)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature and salinity profiles were collected from STD casts in the Bering Sea from the SILAS BENT. Data were collected by the University of Alaska - Fairbanks...

  13. Effects of molecular chirality on self-assembly and switching in liquid crystals at the cross-over between rod-like and bent shapes.

    Science.gov (United States)

    Ocak, Hale; Poppe, Marco; Bilgin-Eran, Belkız; Karanlık, Gürkan; Prehm, Marko; Tschierske, Carsten

    2016-09-21

    A bent-core compound derived from a 4-cyanoresorcinol core unit with two terephthalate based rod-like wings and carrying chiral 3,7-dimethyloctyloxy side chains has been synthesized in racemic and enantiomerically pure form and characterized by polarizing microscopy, differential scanning calorimetry, X-ray diffraction and electro-optical investigations to study the influence of molecular chirality on the superstructural chirality and polar order in lamellar liquid crystalline phases. Herein we demonstrate that the coupling of molecular chirality with superstructural layer chirality in SmCsPF domain phases (forming energetically distinct diastereomeric pairs) can fix the tilt direction and thus stabilize synpolar order, leading to bistable ferroelectric switching in the SmC* phases of the (S)-enantiomer, whereas tristable modes determine the switching of the racemate. Moreover, the mechanism of electric field induced molecular reorganization changes from a rotation around the molecular long axis in the racemate to a rotation on the tilt-cone for the (S)-enantiomer. At high temperature the enantiomer behaves like a rod-like molecule with a chirality induced ferroelectric SmC* phase and an electroclinic effect in the SmA'* phase. At reduced temperature sterically induced polarization, due to the bent molecular shape, becomes dominating, leading to much higher polarization values, thus providing access to high polarization ferroelectric materials with weakly bent compounds having only "weakly chiral" stereogenic units. Moreover, the field induced alignment of the SmCsPF(()*()) domains gives rise to a special kind of electroclinic effect appearing even in the absence of molecular chirality. Comparison with related compounds indicates that the strongest effects of chirality appear for weakly bent molecules with a relatively short coherence length of polar order, whereas for smectic phases with long range polar order the effects of the interlayer interfaces can override

  14. HEGEL主设计师BENT HOLTER来穗主持新品H300放大器产品发布会

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    2012年9月24日下午,广州昌业音响举行HegelH300合并放大器新品发布会。该发布会由Hegel创办人兼主设计师BentHolter亲自主持.并请来本地主要音响媒体及相关人员十多人参加了本次产品发布会。

  15. Deflection of 200 GeV/c and 450 GeV/c positively charged particles in a bent germanium crystal

    Science.gov (United States)

    Biino, C.; Clement, M.; Doble, N.; Elsener, K.; Freund, A.; Gatignon, L.; Grafström, P.; Kirsebom, K.; Mikkelsen, U.; Møller, S. P.; Uggerhøj, E.; Worm, T.

    1997-02-01

    Experimental results on high-energy beam deflection by means of a bent germanium crystal are presented. Record deflection efficiencies of 60% have been found for 450 GeV/c protons at small angles. The results obtained with 200 and 450 GeV/c positively charged particles are well described by a classical model, giving confidence in predictions for other crystals and different beam momenta.

  16. Deflection of 200 GeV/c and 450 GeV/c Positively Charged Particles in a Bent Germanium Crystal

    CERN Document Server

    Biino, C; Doble, Niels T; Elsener, K; Freund, A; Gatignon, L; Grafström, P; Kirsebom, K; Mikkelsen, U; Møller, S P; Uggerhøj, Erik; Worm, T

    1997-01-01

    Experimental results on high-energy beam deflection by means of a bent germanium crystal are presented. Record deflection efficiencies of 60% have been found for 450 GeV/c protons at small angles. The results obtained with 200 and 450 GeV/c positively charged particles are well described by a classical model, giving confidence in predictions for other crystals and different beam momenta.

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

    Science.gov (United States)

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

    2016-07-01

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

  18. Optimization and Annual Average Power Predictions of a Backward Bent Duct Buoy Oscillating Water Column Device Using the Wells Turbine.

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Christopher S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bull, Diana L [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Willits, Steven M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Fontaine, Arnold A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-08-01

    This Technical Report presents work completed by The Applied Research Laboratory at The Pennsylvania State University, in conjunction with Sandia National Labs, on the optimization of the power conversion chain (PCC) design to maximize the Average Annual Electric Power (AAEP) output of an Oscillating Water Column (OWC) device. The design consists of two independent stages. First, the design of a floating OWC, a Backward Bent Duct Buoy (BBDB), and second the design of the PCC. The pneumatic power output of the BBDB in random waves is optimized through the use of a hydrodynamically coupled, linear, frequency-domain, performance model that links the oscillating structure to internal air-pressure fluctuations. The PCC optimization is centered on the selection and sizing of a Wells Turbine and electric power generation equipment. The optimization of the PCC involves the following variables: the type of Wells Turbine (fixed or variable pitched, with and without guide vanes), the radius of the turbine, the optimal vent pressure, the sizing of the power electronics, and number of turbines. Also included in this Technical Report are further details on how rotor thrust and torque are estimated, along with further details on the type of variable frequency drive selected.

  19. Structure of dimeric, recombinant Sulfolobus solfataricus phosphoribosyl diphosphate synthase: a bent dimer defining the adenine specificity of the substrate ATP.

    Science.gov (United States)

    Andersen, Rune W; Leggio, Leila Lo; Hove-Jensen, Bjarne; Kadziola, Anders

    2015-03-01

    The enzyme 5-phosphoribosyl-1-α-diphosphate (PRPP) synthase (EC 2.7.6.1) catalyses the Mg(2+)-dependent transfer of a diphosphoryl group from ATP to the C1 hydroxyl group of ribose 5-phosphate resulting in the production of PRPP and AMP. A nucleotide sequence specifying Sulfolobus solfataricus PRPP synthase was synthesised in vitro with optimised codon usage for expression in Escherichia coli. Following expression of the gene in E. coli PRPP synthase was purified by heat treatment and ammonium sulphate precipitation and the structure of S. solfataricus PRPP synthase was determined at 2.8 Å resolution. A bent dimer oligomerisation was revealed, which seems to be an abundant feature among PRPP synthases for defining the adenine specificity of the substrate ATP. Molecular replacement was used to determine the S. solfataricus PRPP synthase structure with a monomer subunit of Methanocaldococcus jannaschii PRPP synthase as a search model. The two amino acid sequences share 35 % identity. The resulting asymmetric unit consists of three separated dimers. The protein was co-crystallised in the presence of AMP and ribose 5-phosphate, but in the electron density map of the active site only AMP and a sulphate ion were observed. Sulphate ion, reminiscent of the ammonium sulphate precipitation step of the purification, seems to bind tightly and, therefore, presumably occupies and blocks the ribose 5-phosphate binding site. The activity of S. solfataricus PRPP synthase is independent of phosphate ion.

  20. Collapsed bipolar glycolipids at the air/water interface: effect of the stereochemistry on the stretched/bent conformations.

    Science.gov (United States)

    Jacquemet, Alicia; Terme, Nolwenn; Benvegnu, Thierry; Vié, Véronique; Lemiègre, Loïc

    2013-12-15

    This article describes a comparative study of several bipolar lipids derived from tetraether structures. The sole structural difference between the main two glycolipids is a unique stereochemical variation on a cyclopentyl ring placed in the middle of the lipids. We discuss the comparative results obtained at the air/water interface on the basis of tensiometry and ellipsometry. Langmuir-Blodgett depositions during lipid film compressions and decompressions were also analyzed by AFM. The lactosylated tetraether (bipolar) lipid structures involved the formation of highly stable multilayers, which are still present at 10 mN m(-1) during decompression. This study suggests also that the stereochemistry of a central cyclopentyl ring dramatically drives the conformation of the corresponding bipolar lipids. Both isomers (trans and cis) adopt a U-shaped (bent) conformation at the air/water interface but the trans cyclopentyl ring induces a much more frustration within this type of conformation. Consequently, this bipolar lipid (trans-tetraether) undergoes a flip of one polar head-group (lactosyl) leading to a stretched conformation during collapse.

  1. Fiber-to-Waveguide and 3D Chip-to-Chip Light Coupling Based on Bent Metal-Clad Waveguides

    CERN Document Server

    Lu, Zhaolin; Shi, Kaifeng

    2016-01-01

    Efficient fiber-to-waveguide light coupling has been a key issue in integrated photonics for many years. The main challenge lies in the huge mode mismatch between an optical fiber and a single mode waveguide. Herein, we present a novel fiber-to-waveguide coupler, named "L-coupler", through which the light fed from the top of a chip can bend 90{\\deg} with low reflection and is then efficiently coupled into an on-chip Si waveguide within a short propagation distance (<20{\\mu}m). The key element is a bent metal-clad waveguide with a big matched input port. According to our finite-difference time-domain (FDTD) simulation, the coupling efficiency is over 80% within a broad range of working wavelengths in the near-infrared regime for a transverse electric input Gaussian wave. The coupler is polarization-dependent, with very low coupling efficiency (6%-9%) for transverse magnetic waves. The coupler can also be used for three-dimensional (3D) chip-to-chip optical interconnection by efficiently coupling light into ...

  2. Bent paths of a positive streamer and a cathode-directed spark leader in diffuse discharges preionized by runaway electrons

    Science.gov (United States)

    Zhang, Cheng; Tarasenko, Viktor F.; Shao, Tao; Beloplotov, Dmitry V.; Lomaev, Mikhail I.; Wang, Ruixue; Sorokin, Dmitry A.; Yan, Ping

    2015-03-01

    Diffuse discharges preionized by runaway electrons can produce large-area homogeneous discharges at elevated pressures, which is an intriguing phenomenon in the physics of pulsed discharges. In this paper, runaway-electron-preionized diffuse discharge (REP DD) was obtained in a wide pressure range (0.05-0.25 MPa), and under certain conditions a positive streamer and a cathode-directed spark leader could be observed to propagate at some angles to the applied (background) electric field lines. For a 16-mm gap at an air pressure of 0.08-0.1 MPa, the percentage of pulses in which such propagation is observed is about 5%-50% of their total number, and in the other pulses such bent paths could not be observed because there is even no streamer or cathode-directed spark leader in diffuse discharges. In our opinion, such propagation of the positive streamer and the cathode-directed spark leader at some angle to the background electric field lines owes to different increase rates of the electron density in different regions of the discharge volume under REP DD conditions. Therefore, during the formation of a REP DD, the increase of the electron density is inhomogeneous and nonsimultaneous, resulting in an electron density gradient at the ionization wave front.

  3. High resolution short focal distance Bent Crystal Laue Analyzer for copper K edge x-ray absorption spectroscopy.

    Science.gov (United States)

    Kujala, N G; Karanfil, C; Barrea, R A

    2011-06-01

    We have developed a compact short focal distance Bent Crystal Laue Analyzer (BCLA) for Cu speciation studies of biological systems with specific applications to cancer biology. The system provides high energy resolution and high background rejection. The system is composed of an aluminum block serving as a log spiral bender for a 15 micron thick Silicon 111 crystal and a set of soller slits. The energy resolution of the BCLA-about 14 eV at the Cu Kα line- allows resolution of the Cu Kα(1) and CuKα(2) lines. The system is easily aligned by using a set of motorized XYZ linear stages. Two operation modes are available: incident energy scans (IES) and emission energy scans (EES). IES allows scanning of the incident energy while the BCLA system is maintained at a preselected fixed position--typically CuKα(1) line. EES is used when the incident energy is fixed and the analyzer is scanned to provide the peak profile of the emission lines of Cu.

  4. Bent paths of a positive streamer and a cathode-directed spark leader in diffuse discharges preionized by runaway electrons

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Cheng; Shao, Tao, E-mail: st@mail.iee.ac.cn; Wang, Ruixue; Yan, Ping [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Key Laboratory of Power Electronics and Electric Drive, Chinese Academy of Sciences, Beijing 100190 (China); Tarasenko, Viktor F.; Beloplotov, Dmitry V.; Lomaev, Mikhail I.; Sorokin, Dmitry A. [Institute of High Current Electronics, Russian Academy of Science, Tomsk 634055 (Russian Federation); National Research Tomsk State University, 36 Lenin Ave., Tomsk 634050 (Russian Federation)

    2015-03-15

    Diffuse discharges preionized by runaway electrons can produce large-area homogeneous discharges at elevated pressures, which is an intriguing phenomenon in the physics of pulsed discharges. In this paper, runaway-electron-preionized diffuse discharge (REP DD) was obtained in a wide pressure range (0.05–0.25 MPa), and under certain conditions a positive streamer and a cathode-directed spark leader could be observed to propagate at some angles to the applied (background) electric field lines. For a 16-mm gap at an air pressure of 0.08–0.1 MPa, the percentage of pulses in which such propagation is observed is about 5%–50% of their total number, and in the other pulses such bent paths could not be observed because there is even no streamer or cathode-directed spark leader in diffuse discharges. In our opinion, such propagation of the positive streamer and the cathode-directed spark leader at some angle to the background electric field lines owes to different increase rates of the electron density in different regions of the discharge volume under REP DD conditions. Therefore, during the formation of a REP DD, the increase of the electron density is inhomogeneous and nonsimultaneous, resulting in an electron density gradient at the ionization wave front.

  5. Manufacturing and characterization of bent silicon crystals for studies of coherent interactions with negatively charged particles beams

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-15

    Efficient steering of GeV-energy negatively charged particle beams was demonstrated to be possible with a new generation of thin bent silicon crystals. Suitable crystals were produced at the Sensor Semiconductor Laboratory of Ferrara starting from Silicon On Insulator wafers, adopting proper revisitation of silicon micromachining techniques such as Low Pressure Chemical Vapor Deposition, photolithography and anisotropic chemical etching. Mechanical holders, which allow to properly bend the crystal and to reduce unwanted torsions, were employed. Crystallographic directions and crystal holder design were optimized in order to excite quasi-mosaic effect along (1 1 1) planes. Prior to exposing the crystal to particle beams, a full set of characterizations were performed. Infrared interferometry was used to measure crystal thickness with high accuracy. White-light interferometry was employed to characterize surface deformational state and its torsion. High-resolution X-rays diffraction was used to precisely measure crystal bending angle along the beam. Manufactured crystals were installed and tested at the MAMI MAinz MIcrotron to steer sub-GeV electrons, and at SLAC to deflect an electron beam in the 1 to 10 GeV energy range.

  6. Method for characterization of a spherically bent crystal for K.alpha. X-ray imaging of laser plasmas using a focusing monochromator geometry

    Science.gov (United States)

    Kugland, Nathan; Doeppner, Tilo; Glenzer, Siegfried; Constantin, Carmen; Niemann, Chris; Neumayer, Paul

    2015-04-07

    A method is provided for characterizing spectrometric properties (e.g., peak reflectivity, reflection curve width, and Bragg angle offset) of the K.alpha. emission line reflected narrowly off angle of the direct reflection of a bent crystal and in particular of a spherically bent quartz 200 crystal by analyzing the off-angle x-ray emission from a stronger emission line reflected at angles far from normal incidence. The bent quartz crystal can therefore accurately image argon K.alpha. x-rays at near-normal incidence (Bragg angle of approximately 81 degrees). The method is useful for in-situ calibration of instruments employing the crystal as a grating by first operating the crystal as a high throughput focusing monochromator on the Rowland circle at angles far from normal incidence (Bragg angle approximately 68 degrees) to make a reflection curve with the He-like x-rays such as the He-.alpha. emission line observed from a laser-excited plasma.

  7. Design of a Broadband E-Plane Power Combiner Based on Quarter-Arc Bent Rectangular Waveguides for Sub-THz and THz Wave

    Institute of Scientific and Technical Information of China (English)

    Xiao-Pin Tang; Zi-Qiang Yang; Zong-Jun Shi; Feng Lan

    2016-01-01

    A method of designing an E-plane power combiner composed of two quarter-arc bent rectangular waveguides is proposed for sub-THz and THz waves.The quarter-arc bent-waveguide power combiner has a simple geometry which is easy to design and fabricate.By HFSS codes,the physical mechanism and performance of the power combiner are analyzed,and the relationship between the output characteristics and the structure/operating parameters is given.Simulation results show that our power combiner is suitable for the combining of two equalpower and reversed-phase signals,the bandwidth of the combiner is wide and can be adjusted by the radius of the quarter-arc,and the isolation performance of the combiner can be improved by adding thin film resistive septa at the junction of two quarter-arc bent waveguides.Meanwhile,an approximate method based on the analytic geometrical analysis is given to design this power combiner for different frequency bands.

  8. Gelation behaviour of a bent-core dihydrazide derivative: effect of incubation temperature in chloroform and toluene.

    Science.gov (United States)

    Zhang, Chunxue; Zhang, Tianren; Ji, Nan; Zhang, Yan; Bai, Binglian; Wang, Haitao; Li, Min

    2016-02-01

    In this work, a new kind of gelator, 1,3-bis[(3,4-dioctyloxy phenyl) hydrazide]phenylene (BP8-C), containing two dihydrazide units as the rigid bent-core, has been synthesized and investigated. It was demonstrated that BP8-C is an efficient gelator which can gel various organic solvents, such as ethanol, benzene, toluene, chloroform, etc. Both an opaque gel (O-gel) and a transparent gel (T-gel), which is more stable, were obtained with BP8-C in chloroform at different incubation temperatures. Kinetic data based on fluorescence spectra revealed that the T-gels showed a larger Avrami parameter (n = 1.44 at 20 °C) than that of the O-gels (n = 1.21 for gelation at temperatures below 0 °C). While BP8-C did form the opaque gel in toluene, gelation took longer at lower incubation temperatures and even precipitated out below 0 °C. The kinetic Avrami analysis on sols of BP8-C with different concentrations shows a two-phrase mechanism, i.e. the n values are between 0.88 and 1.74 followed by 1.69 and 3.01 throughout the temperature range of 5 °C and 35 °C for 5.34 mg mL(-1) BP8-C in toluene, indicating that the fibers formed first and then bundled to produce compact networks. We propose that supersaturation governs the formation of gel in chloroform and that the diffusion process denominates gelation in toluene. XRD and FT-IR measurements confirmed that the xerogels prepared at different temperatures in different solvents exhibited a Col(h) structure and that there are three molecules in one columnar slice. Our results indicate that the gelation process, morphology of the gels and thus the final properties of the gels depend strongly on the preparation conditions such as temperature, solvent, concentration, etc.

  9. Combining flat crystals, bent crystals and compound refractive lenses for high-energy X-ray optics.

    Science.gov (United States)

    Shastri, S D

    2004-03-01

    Compound refractive lenses (CRLs) are effective for collimating or focusing high-energy X-ray beams (50-100 keV) and can be used in conjunction with crystal optics in a variety of configurations, as demonstrated at the 1-ID undulator beamline of the Advanced Photon Source. As a primary example, this article describes the quadrupling of the output flux when a collimating CRL, composed of cylindrical holes in aluminium, is inserted between two successive monochromators, i.e. a modest-energy-resolution premonochromator followed by a high-resolution monochromator. The premonochromator is a cryogenically cooled divergence-preserving bent double-Laue Si(111) crystal device delivering an energy width DeltaE/E approximately 10(-3), which is sufficient for most experiments. The high-resolution monochromator is a four-reflection flat Si(111) crystal system resembling two channel-cuts in a dispersive arrangement, reducing the bandwidth to less than 10(-4), as required for some applications. Tests with 67 and 81 keV photon energies show that the high-resolution monochromator, having a narrow angular acceptance of a few microradians, exhibits a fourfold throughput enhancement due to the insertion of a CRL that reduces the premonochromatized beam's vertical divergence from 29 micro rad to a few microradians. The ability to focus high-energy X-rays with CRLs having long focal lengths (tens of meters) is also shown by creating a line focus of 70-90 micro m beam height in the beamline end-station with both the modest-energy-resolution and the high-energy-resolution monochromatic X-rays.

  10. Revisiting the chemistry of the actinocenes [(η8-C8H8)2An] (An = U, Th) with neutral Lewis bases. Access to the bent sandwich complexes [(η8-C8H8)2An(L)] with thorium (L = py, 4,4'-bipy, tBuNC, R4phen).

    Science.gov (United States)

    Berthet, Jean-Claude; Thuéry, Pierre; Garin, Nicolas; Dognon, Jean-Pierre; Cantat, Thibault; Ephritikhine, Michel

    2013-07-10

    In stark contrast to uranocene, (Cot)2Th reacts with neutral mono- or bidentate Lewis bases to give the bent sandwich complexes (Cot)2Th(L) (L = py, 4,4'-bipy, tBuNC, phen, Me4phen). DFT calculations in the gas phase show that, for both U and Th, formation of the bent compound (Cot)2An(L) should be facile, the linear and bent forms being close in energy.

  11. Experimental study of the radiation emitted by 180-GeV/c electrons and positrons volume-reflected in a bent crystal

    CERN Document Server

    Scandale, Walter; Baricordi, S; Dalpiaz, P; Fiorini, M; Guidi, V; Mazzolari, A; Della Mea, G; Milan, R; Ambrosi, G; Zuccon, P; Bertucci, B; Bürger, W; Duranti, M; Cavoto, G; Santacesaria, R; Valente, P; Luci, C; Iacoangeli, F; Vallazza, E; Afonin, A G; Chesnokov, Yu A; Kotov, V I; Maisheev, V A; Yazynin, I A; Kovalenko, A D; Taratin, A M; Denisov, A S; Gavrikov, Y A; Ivanov, Yu M; Lapina, L P; Malyarenko, L G; Skorogobogatov, V V; Suvorov, V M; Vavilov, S A; Bolognini, D; Hasan, S; Mozzanica, A; Prest, M

    2009-01-01

    The radiation emitted by 180-GeV/c volume-reflected electrons and positrons impinging on a bent crystal has been measured by the H8RD22 Collaboration on the H8 beamline at the CERN SPS. A dedicated spectrometer has been developed to measure high-energy photon spectra (up to ~100 GeV) under volume reflection: photon and charged particle beams have been separated by a bending magnet and leptons were detected and tagged by microstrip silicon detectors and a Pb-scintillator sampling calorimeter. A comparison between the experimental and analytical data for the amorphous and volume-reflection cases is presented and the differences are discussed.

  12. COMPARISON OF THE EFFECTIVENESS BETWEEN ANTERIOR CAPSULOTOMY WITH Nd:YAG LASER AND WITH BENT NEEDLE IN PATIENTS WITH CONGENITAL CATARACT

    Institute of Scientific and Technical Information of China (English)

    1991-01-01

    The effectiveness of capsulotomy with Nd:YAG laser and with bent needle were compared in 50 patients(66 eyes) with congenital cataract. There were 24 patients(32 eyes) in the laser group and 26 patients(34 eyes) in the needle group. There were not significant differences in sex, age, pre-operative visual acuity and intraocular pressures, and classification of cataract between the two groups. The results show that patients in the laser group have better post-operative visual acuity. The reason is YAG las...

  13. Subcarrier phase recovery performance in bent-pipe mode of Shuttle data transmission. [on Tracking and Data Relay Satellite System Ku-band return link

    Science.gov (United States)

    Mckenzie, T. M.; Braun, W. R.

    1978-01-01

    The subcarrier phase recovery is analyzed for the bent-pipe mode of Space Shuttle detached-payload data transmission on the Tracking and Data Relay Satellite System (TDRSS) Ku-band return link. The high-power component of the subcarrier modulation is unrestored payload data, either at baseband or modulating another subcarrier. At the receiver a Costas loop recovers the subcarrier phase. To analyze its performance in the baseband case, we obtain the loop S-curve, the power spectral density of the equivalent noise process, and the loop phase error variance.

  14. Crutch art painting in the Middle Ages as orthopaedic heritage (part II: the peg leg, the bent-knee peg and the beggar).

    Science.gov (United States)

    Hernigou, Philippe

    2014-07-01

    Little of historical value about crutches can be ascertained before the Middle Ages. In contrast, the Middle Ages offer many examples for the study of crutches. Even if no medical report can be found, the immense patronage of the Church, encouraging artists to portray the saints and their miracles, has left great masterpieces that drew people with crutches. Pictures and the history of medieval conceptions of disability appear to provide an interesting chronicle of surgery of the peg leg and the bent-knee peg among the representations of cripples and beggars.

  15. Condicionantes ambientales de comunidades de foraminíferos bentónicos durante el pleistoceno medio en el Atlántico sudoccidental

    Directory of Open Access Journals (Sweden)

    Cecilia Laprida

    2014-09-01

    Full Text Available El océano Atlántico Sur es clave en la distribución de masas de agua profunda hacia otros océanos. Dado el papel que juega la circulación termohalina en el clima, el reconocimiento de variaciones en su distribución durante los ciclos glaciales/interglaciales reviste gran interés. Los foraminíferos bentónicos son utilizados como herramientas de reconstrucción paleoceanográfica, y la existencia de especies asociadas a masas de agua fue utilizada para definir cambios en la circulación oceánica profunda. Sin embargo, la relación entre foraminíferos bentónicos y masas de agua es controversial. Con el objetivo de determinar si las asociaciones de foraminíferos bentónicos reflejan la distribución de las masas de agua profunda durante un evento glacial del Pleistoceno Medio, se analizó un testigo ubicado en el límite entre dos masas de agua profunda: la North Atlantic Deep Water y la Circumpolar Deep Water. En las asociaciones se hallaron especies consideradas indicadoras de ambas masas de agua, aunque algunas especies asociadas a la Circumpolar Deep Water presentan abundancias relativas mayores, siendo Uvigerina peregrina dominante en ciertos niveles. Sin embargo, la escasa abundancia de Globocassidulina subglobosa, asociada a la Circumpolar Deep Water, y la constancia en el porcentaje de especies consideradas indicadoras de la North Atlantic Deep Water impiden atribuir la dominancia de Uvigerina peregrina a una mayor influencia de la Circumpolar Deep Water. El hecho de que esta especie está asociada a flujos elevados de materia orgánica y que su mayor dominancia coincida con aumentos en la abundancia de Globigerina bulloides indica que la productividad superficial fue el factor determinante en la estructuración de las asociaciones de foraminíferos bentónicos en el talud norbonaerense durante el Pleistoceno Medio.

  16. Influence of moieties for the phase stability, spontaneous polarization and dielectric relaxations in an achiral ferroelectric bent liquid crystal, PBUOB

    Energy Technology Data Exchange (ETDEWEB)

    Chalapathi, P.V. [Department of Physics, A.K.R.G. College of Engineering and Technology, Nallajerla 534112 (India); Srinivasulu, M. [Department of Chemistry, Manipal Institute of Technology, Manipal University, Manipal 576104 (India); Pisipati, V.G.K.M. [Department of Electronics and Communications Engineering, R and D Division, KL-University, Vaddeswaram (India); Satyanarayana, Ch. [Department of Computers Science Engineering, University College of Engineering, Jawaharlal Nehru Technological University: Kakinada, Kakinada 533003 (India); Potukuchi, D.M., E-mail: potukuchidm@yahoo.co [Department of Physics, University College of Engineering, Jawaharlal Nehru Technological University: Kakinada, Kakinada 533003 (India)

    2011-05-15

    The occurrence of ferroelectric phases and influence of chemical moieties in the area of supra-molecular achiral Bent core Liquid Crystals (BLCs) are reviewed. Synthesis of an intermediate/higher homolog of PBnOB series (for n=11), PBUOB, viz. 1,3-Phenyline-Bis(4-UndecylOxy Benzoate), is presented. Smectic LC phases exhibited by PBUOB are characterized by Polarized Optical Microscopy (POM), Differential Scanning Calorimetry (DSC) and Spontaneous Polarization (P{sub S}) techniques. Observations infer a bi-variant FE LC smectic phase occurrence, viz., isotropic{yields}B{sub 2}(FE){yields}B{sub 5}(FE){yields}solid phases in cooling and solid{yields}B{sub 5{yields}}isotropic phases in heating scans. Occurrence of B{sub 2} phase is monotropic (in cooling), while B{sub 5} phase is enantiotropic. I-B{sub 2} and B{sub 2}-B{sub 5} phase transitions are found to be of first order nature. The FE phases possess a moderate P{sub S} value of {approx}40 nC cm{sup -2}. Transition temperatures from dielectric studies agree with those from TM and DSC. Two modes of relaxations are observed, viz., a slow scissor mode at {approx}1 kHz and a fast mode at {approx}1 MHz. Anisotropic Dipolar Model is proposed to explain the reorientation mechanism. Arrhenius shifts of Relaxation Frequency (f{sub R}) show differing activation energies for two modes, i.e., 0.11 and 0.98 eV; 0.25 and 1.18 eV in B{sub 2} and B{sub 5} phases, respectively. Temperature variation of dielectric increment {Delta}{epsilon} and {alpha}-parameter LC phases reveals the relative fixture of dipole moment in polar smectic layers. An analytical study for the thermal stability, P{sub S} and f{sub R} in the FE phases is presented with respect to the constitution and configuration of moieties in BLCs.

  17. Bent But Not Broken

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    People in the earthquake zo task to return their lives to positive in spite of it One week after the 8.0-magnitude earthquake in southwestern Sichuan Province, 57-year-old farmer Li Fangyi of Anxian County, for the first time returned to his farmland to harvest wheat and rapeseed,

  18. Highly-sensitive detection of the lattice distortion in single bent ZnO nanowires by second-harmonic generation microscopy

    CERN Document Server

    Han, Xiaobo; Long, Hua; Hu, Hongbo; Chen, Jiawei; Wang, Bing; Lu, Peixiang

    2015-01-01

    Nanogenerators based on ZnO nanowires (NWs) realize the energy conversion at nanoscale, which are ascribed to the piezoelectric property caused by the lattice distortion of the ZnO NWs. The lattice distortion can significantly tune the electronic and optical properties, and requires a sensitive and convenient measurement. However, high-resolution transmission electron microscopy (HRTEM) technique provides a limited sensitivity of 0.01 nm on the variation of the lattice spacing and requires vacuum conditions. Here we demonstrate a highly-sensitive detection of the lattice distortion in single bent ZnO NWs by second-harmonic generation (SHG) microscopy. As the curvature of the single bent ZnO NW increases to 21 mm-1 (<4% bending distortion), it shows a significant decrease (~70%) in the SHG intensity ratio between perpendicular and parallel excitation polarization with respect to c-axis of ZnO NWs. Importantly, the extraordinary non-axisymmetrical SHG polarimetric patterns are also observed, indicating the t...

  19. Dark conglomerate phases of azobenzene derived bent-core mesogens - relationships between the molecular structure and mirror symmetry breaking in soft matter.

    Science.gov (United States)

    Alaasar, Mohamed; Prehm, Marko; Brautzsch, Marcel; Tschierske, Carsten

    2014-10-07

    New 4-bromoresorcinol based bent-core molecules with peripheral fluoro substituted azobenzene wings have been synthesized and the liquid crystalline self-assembly was investigated by differential scanning calorimetry (DSC), optical polarizing microscopy (POM), electro-optic studies and X-ray diffraction (XRD). A new type of optically isotropic mesophase composed of chiral domains with opposite handedness (dark conglomerate phases, DC phases) is observed, which for some homologues with medium alkyl chain length is stable down to ambient temperature. It is proposed that these DC phases are formed by helical twisted nano-domains of limited size and composed of the crystallized aromatic cores which are separated by the disordered alkyl chains. This structure is distinct from the previously known soft helical nano-filament phases (HNF phases, B4 phases) formed by extended crystalline nano-filaments and also distinct from the fluid sponge phases composed of deformed fluid layers. Comparison with related bent-core molecules having H, F, Cl, I, CH3 and CN groups in the 4-position at the resorcinol core, either with or without additional peripheral fluorines, provided information about the effects of these substituents on the tendency to form DC phases. Based on these relationships and by comparison with the minimum energy conformations obtained by DFT calculations a hypothesis is provided for the formation of DC phases depending on the molecular structure.

  20. An X-ray Raman spectrometer for EXAFS studies on minerals: bent Laue spectrometer with 20 keV X-rays.

    Science.gov (United States)

    Hiraoka, N; Fukui, H; Tanida, H; Toyokawa, H; Cai, Y Q; Tsuei, K D

    2013-03-01

    An X-ray Raman spectrometer for studies of local structures in minerals is discussed. Contrary to widely adopted back-scattering spectrometers using ≤10 keV X-rays, a spectrometer utilizing ~20 keV X-rays and a bent Laue analyzer is proposed. The 20 keV photons penetrate mineral samples much more deeply than 10 keV photons, so that high intensity is obtained owing to an enhancement of the scattering volume. Furthermore, a bent Laue analyzer provides a wide band-pass and a high reflectivity, leading to a much enhanced integrated intensity. A prototype spectrometer has been constructed and performance tests carried out. The oxygen K-edge in SiO(2) glass and crystal (α-quartz) has been measured with energy resolutions of 4 eV (EXAFS mode) and 1.3 eV (XANES mode). Unlike methods previously adopted, it is proposed to determine the pre-edge curve based on a theoretical Compton profile and a Monte Carlo multiple-scattering simulation before extracting EXAFS features. It is shown that the obtained EXAFS features are reproduced fairly well by a cluster model with a minimal set of fitting parameters. The spectrometer and the data processing proposed here are readily applicable to high-pressure studies.

  1. Suficiência amostral para estudos de impacto ambiental sobre a comunidade de macroinvertebrados bentônicos em arrozais irrigados

    Directory of Open Access Journals (Sweden)

    Alana Cristina Dorneles Wandscheer

    2016-01-01

    Full Text Available RESUMO: O objetivo deste estudo foi determinar a suficiência amostral para estudos de impacto ambiental sobre a comunidade de macroinvertebrados bentônicos em arrozais irrigados (Oryza sativa L.. Amostragens de solo foram realizadas com auxílio de coletor cilíndrico, nos anos agrícolas 2007/08 e 2012/13. As amostras foram triadas e os espécimes identificados até o nível de família. Os dados foram submetidos à análise da curva do coletor e os índices de diversidade de Shannon e equabilidade de Pielou foram calculados para o total de amostras e o número de amostras definido pela curva do coletor, em cada ano amostral. Considerando o método de amostragem verificado no presente trabalho, indica-se um mínimo de 12 réplicas para se obter o maior número de famílias sem perda de informação, quando em estudos de impacto ambiental sobre a comunidade de macroinvertebrados bentônicos em área de cultivo de arroz irrigado.

  2. 竖向框排架厂房柱间支撑设计%On support design for column bracing at workshops of vertical frame-bent structures

    Institute of Scientific and Technical Information of China (English)

    尹航; 张矿三

    2015-01-01

    Taking the vertical frame-bent structure of compressor in some project of Xinjiang as the example,the paper analyzes the modeling cal-culation of the workshop,and explores the column bracing design principle and calculation methods for the vertical frame-bent structure at high earthquake intensity areas by combining with the national regulations and rules,so as to provide some reference for related engineering design.%以新疆某工程中压缩机厂房竖向框排架结构设计为例,通过对此厂房的建模计算分析,结合国家规范条文,探讨了在高地震烈度地区竖向框排架结构的柱间支撑设计原则与计算方法,为相关工程设计提供参考。

  3. Foraminíferos planctônicos e bentônicos do intervalo aptianoalbiano do DSDP Site 364 (bacia de Kwanza): taxonomia, bioestratigrafia, paleoecologia e implicações paleoceanográficas

    OpenAIRE

    Kochhann, Karlos Guilherme Diemer

    2012-01-01

    O presente estudo apresenta a taxonomia, bioestratigrafia e paleoecologia dos foraminíferos planctônicos e bentônicos recuperados no intervalo Aptiano superiorAlbiano da sucessão dominantemente carbonática do Deep Sea Drilling Project (DSDP) Site 364, localizado na bacia de Kwanza (costa afora de Angola). Foram identificadas 30 espécies de foraminíferos planctônicos e 42 espécies de foraminíferos bentônicos. Com base nas assembleias de foraminíferos planctônicos, a seção sedimentar estudada f...

  4. Strong suppression of nuclear-charge changing interactions for 18 TeV/c In ions channeled through a bent Si crystal

    Energy Technology Data Exchange (ETDEWEB)

    Uggerhoj, U.I. [Department of Physics and Astronomy, University of Aarhus (Denmark)]. E-mail: ulrik@phys.au.dk; Hansen, H.D. [Department of Physics and Astronomy, University of Aarhus (Denmark); Jessen, K. [Department of Physics and Astronomy, University of Aarhus (Denmark); Knudsen, H. [Department of Physics and Astronomy, University of Aarhus (Denmark); Uggerhoj, E. [Department of Physics and Astronomy, University of Aarhus (Denmark); Scheidenberger, C. [GSI, Darmstadt (Germany); Biino, C. [CERN, Geneva (Switzerland); Clement, M. [CERN, Geneva (Switzerland); Doble, N. [CERN, Geneva (Switzerland); Elsener, K. [CERN, Geneva (Switzerland); Gatignon, L. [CERN, Geneva (Switzerland); Grafstroem, P. [CERN, Geneva (Switzerland); Sona, P. [University of Florence, Florence (Italy); Mangiarotti, A. [University of Florence, Florence (Italy); Ballestrero, S. [University of Florence, Florence (Italy)

    2005-07-21

    We present experimental results giving evidence for the strong reduction-a factor of more than 20-of nuclear-charge changing interactions for 18 TeV In{sup 49+} ions channeled through a silicon crystal bent to 7.5, 11.9 and 19.8 mrad. A very small fraction of the deflected ions suffer electromagnetic or nuclear interactions leading to proton loss while traversing the 60 mm long crystal, even though its thickness corresponds to about 0.13 nuclear interaction lengths for an amorphous material. By considering the deflected ions only, we show experimentally that the nuclear-charge pickup reaction believed to be induced by virtual photons is a short-range phenomenon.

  5. High-efficiency deflection of high energy protons due to channeling along the 〈110〉 axis of a bent silicon crystal

    Directory of Open Access Journals (Sweden)

    W. Scandale

    2016-09-01

    Full Text Available A deflection efficiency of about 61% was observed for 400 GeV/c protons due to channeling, most strongly along the 〈110〉 axis of a bent silicon crystal. It is comparable with the deflection efficiency in planar channeling and considerably larger than in the case of the 〈111〉 axis. The measured probability of inelastic nuclear interactions of protons in channeling along the 〈110〉 axis is only about 10% of its amorphous level whereas in channeling along the (110 planes it is about 25%. High efficiency deflection and small beam losses make this axial orientation of a silicon crystal a useful tool for the beam steering of high energy charged particles.

  6. A possibility of parallel and anti-parallel diffraction measurements on neutron diffractometer employing bent perfect crystal monochromator at the monochromatic focusing condition

    Indian Academy of Sciences (India)

    Yong Nam Choi; Shin Ae Kim; Sung Kyu Kim; Sung Baek Kim; Chang-Hee Lee; Pivel Mikula

    2004-07-01

    In a conventional diffractometer having single monochromator, only one position, parallel position, is used for the diffraction experiment (i.e. detection) because the resolution property of the other one, anti-parallel position, is very poor. However, a bent perfect crystal (BPC) monochromator at monochromatic focusing condition can provide a quite flat and equal resolution property at both parallel and anti-parallel positions and thus one can have a chance to use both sides for the diffraction experiment. From the data of the FWHM and the / measured on three diffraction geometries (symmetric, asymmetric compression and asymmetric expansion), we can conclude that the simultaneous diffraction measurement in both parallel and anti-parallel positions can be achieved.

  7. Sawadalepis prima n. g., n. sp. (Cestoda: Cyclophyllidea) from the Schreiber's bent-winged bat Miniopterus schreibersii Kuhl (Chiroptera: Vespertilionidae) from China.

    Science.gov (United States)

    Makarikova, Tatiana A; Makarikov, Arseny A

    2013-09-01

    Sawadalepis n. g. is erected for Sawadalepis prima n. sp. in Schreiber's bent-winged bat Miniopterus schreibersii Kuhl (Chiroptera: Vespertilionidae) from southern China. Diagnostic features of the currently monotypic genus include attributes of the osmoregulatory system and female genital organs. The dorsal osmoregulatory canals are shifted bilaterally towards the margins of proglottides in relation to the ventral canals. The genital pores are unilateral and sinistral. Among female attributes, the copulatory part of the vagina is covered externally by a dense layer of intensely stained cells; the conductive part of the vagina is clearly distinguishable from the seminal receptacle; the uterus has ventral and dorsal diverticula, extending bilaterally beyond the longitudinal osmoregulatory canals; and the eggs are spherical with thick outer coat.

  8. Optimization of the bent perfect Si(311)-crystal monochromator for a residual strain/stress instrument at the HANARO reactor-Part I

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Myung-Kook [Korea Atomic Energy Research Institute, Neutron Beam Application, 150 Duckjin-Dong, Yusung, Daejon 305-600 (Korea, Republic of)]. E-mail: moonmk@kaeri.re.kr; Lee, Chang-Hee [Korea Atomic Energy Research Institute, Neutron Beam Application, 150 Duckjin-Dong, Yusung, Daejon 305-600 (Korea, Republic of); Em, Vyacheslav T. [Korea Atomic Energy Research Institute, Neutron Beam Application, 150 Duckjin-Dong, Yusung, Daejon 305-600 (Korea, Republic of); Mikula, Pavol [Nuclear Physics Institute and Research Centre Rez, Ltd., 250 68 Rez (Czech Republic); Hong, Kwang-Pyo [Korea Atomic Energy Research Institute, Neutron Beam Application, 150 Duckjin-Dong, Yusung, Daejon 305-600 (Korea, Republic of); Choi, Young-Hyun [Korea Atomic Energy Research Institute, Neutron Beam Application, 150 Duckjin-Dong, Yusung, Daejon 305-600 (Korea, Republic of); Cheon, Jong-Kyu [Korea Atomic Energy Research Institute, Neutron Beam Application, 150 Duckjin-Dong, Yusung, Daejon 305-600 (Korea, Republic of); Choi, Young-Nam [Korea Atomic Energy Research Institute, Neutron Beam Application, 150 Duckjin-Dong, Yusung, Daejon 305-600 (Korea, Republic of); Kim, Shin-Ae [Korea Atomic Energy Research Institute, Neutron Beam Application, 150 Duckjin-Dong, Yusung, Daejon 305-600 (Korea, Republic of); Kim, Sung-Kyu [Korea Atomic Energy Research Institute, Neutron Beam Application, 150 Duckjin-Dong, Yusung, Daejon 305-600 (Korea, Republic of); Jin, Kyung-Chan [Korea Institute of Industrial Technology 35-3 Hongchon-Ri, Ipchang-Myun, Chonan-Si, Chungnam 330-825 (Korea, Republic of)

    2005-12-01

    Reflectivity and resolution properties of a variety of optimized focusing monochromator performances based on cylindrically bent perfect Si-crystals were tested with the aim of evaluating their possible use in a strain/stress diffractometer. It has been found that the optimized monochromator performances of the curved Si(311) crystals (for the take-off angle 2{theta}{sub M}=60 deg.) provide a good luminosity and a sufficiently high resolution (full width at half maximum (FWHM) of the instrumental {delta}d/d-profile can be about 2x10{sup -3} in the vicinity of the lattice spacing d=0.117nm for 2{theta}{sub S}{approx}90 deg.) of the strain/stress diffractometer with the figure of merit more than one order of magnitude larger than that related to the conventional flat mosaic Ge(220) monochromator of {eta}=15{sup '}.

  9. Strong suppression of nuclear-charge changing interactions for 18 TeV/ c In ions channeled through a bent Si crystal

    Science.gov (United States)

    Uggerhøj, U. I.; Hansen, H. D.; Jessen, K.; Knudsen, H.; Uggerhøj, E.; Scheidenberger, C.; Biino, C.; Clément, M.; Doble, N.; Elsener, K.; Gatignon, L.; Grafström, P.; Sona, P.; Mangiarotti, A.; Ballestrero, S.

    2005-07-01

    We present experimental results giving evidence for the strong reduction-a factor of more than 20-of nuclear-charge changing interactions for 18 TeV In49+ ions channeled through a silicon crystal bent to 7.5, 11.9 and 19.8 mrad. A very small fraction of the deflected ions suffer electromagnetic or nuclear interactions leading to proton loss while traversing the 60 mm long crystal, even though its thickness corresponds to about 0.13 nuclear interaction lengths for an amorphous material. By considering the deflected ions only, we show experimentally that the nuclear-charge pickup reaction believed to be induced by virtual photons is a short-range phenomenon.

  10. Dynamics Stability of the Micro Robot Moving in Bent Pipe%管道内微机器人弯管运动的动力学稳定性

    Institute of Scientific and Technical Information of China (English)

    程良伦; 杨宜民

    2001-01-01

    A new type of micro pipe robot is introduced. A constrained micropipe robot dynamic model with frictional contact is proposed, a singular perturbation method is used to reveal additional necessary conditions to ensure contact force stability in the reduced rigid body model. And the stability of the micro pipe robot moving in bent pipe is analyzed.%介绍了一种新型管道内微机器人,根据该机器人建立了有摩擦接触的微机器人受限运动的动力学模型,用奇异摄动法解释了降阶刚体模型接触力稳定性的附加条件.利用该模型分析了管道内微机器人在弯管内运动的稳定性.

  11. A study of Channeling, Volume Reflection and Volume Capture of 3.35 - 14.0 GeV Electrons in a bent Silicon Crystal

    Energy Technology Data Exchange (ETDEWEB)

    Wistisen, T. N. [Aarhus Univ. (Denmark); Uggerhoj, U. I. [Aarhus Univ. (Denmark); Wienands, U. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Markiewicz, T. W. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Noble, R. J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Benson, B. L. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Smith, T. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Bagli, E. [Univ. of Ferrara (Italy); Bandiera, L. [Univ. of Ferrara (Italy); Germogli, G. [Univ. of Ferrara (Italy); Guidi, V. [Univ. of Ferrara (Italy); Mazzolari, A. [Univ. of Ferrara (Italy); Holtzapple, R. [California Polytechnic State Univ. (CalPoly), San Luis Obispo, CA (United States); Tucker, S. [California Polytechnic State Univ. (CalPoly), San Luis Obispo, CA (United States)

    2015-12-03

    We present the experimental data and analysis of experiments conducted at SLAC National Accelerator Laboratory investigating the processes of channeling, volume-reflection and volume-capture along the (111) plane in a strongly bent quasi-mosaic silicon crystal. Additionally, these phenomena were investigated at 5 energies: 3.35, 4.2, 6.3, 10.5 and 14.0 GeV with a crystal with bending radius of 0.15m, corresponding to curvatures of 0.070, 0.088, 0.13, 0.22 and 0.29 times the critical curvature respectively. We have extracted important parameters describing the channeling process such as the dechanneling length, the angle of volume reflection, the surface transmission and the widths of the distribution of channeled particles parallel and orthogonal to the plane.

  12. Acoplamiento pelágico-bentónico: respuesta de la zona bentónica profunda a la sedimentación del florecimiento invernal de diatomeas en el lago oligotrófico Alchichica, Puebla, México Pelagic-benthic coupling: deep benthic zone response to winter diatom bloom sinking in oligotrophic Lake Alchichica, Puebla, Mexico

    Directory of Open Access Journals (Sweden)

    Javier Alcocer

    2008-08-01

    Full Text Available El objetivo del presente estudio es reconocer la existencia de un acoplamiento pelágico-bentónico en el lago oligotrófico tropical Alchichica evaluando la respuesta de la zona bentónica profunda a la sedimentación del florecimiento invernal de diatomeas. Se midió la biomasa fitoplanctónica en la columna de agua a lo largo de un ciclo anual, al igual que la concentración de clorofila a sedimentaria. Alchichica es un lago monomíctico cálido con un periodo de circulación invernal y estratificación el resto del año. La presencia de turbulencia y nutrimentos durante el periodo de circulación favorecen el desarrollo de un florecimiento de diatomeas compuesto por especies de talla grande (p. e., Cyclotella alchichicana, las cuales se sedimentan al no ser consumidas en su totalidad. La zona bentónica profunda del lago responde a la sedimentación del florecimiento invernal de diatomeas con el desarrollo y permanencia por un periodo prolongado de anoxia hipolimnética, lo que a su vez, impide el establecimiento y desarrollo de fauna bentónica en el Lago Alchichica, favorece la pérdida interna de nitrógeno por desnitrificación y consecuentemente, conlleva a que el nitrógeno sea el elemento que más frecuentemente límite el crecimiento fitoplanctónico.The aim of this study is to recognize the existence of a pelagic-benthic coupling in the oligotrophic, tropical Lake Alchichica through analysis of the response of the deep benthic zone to the winter diatom bloom deposition. The water column phytoplankton biomass and the sedimentary chlorophyll a were analyzed along an annual cycle. Alchichica is a warm monomictic lake circulating in winter and stratified over the rest of the year. The presence of turbulence and nutrient availability during the mixing period, favor the development of a diatom bloom composed by large species (e. g., Cyclotella alchichicana which are not totally consumed and settle down. The deep benthic zone responds to

  13. In-situ metrology for the optimization of bent crystals used in hard-X-ray monochromators: Comparison between measurement and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Thomasset, Muriel, E-mail: muriel.thomasset@synchrotron-soleil.f [Synchrotron SOLEIL, L' orme des Merisiers, BP 48, 91192 Gif sur Yvette (France); Moreno, Thierry; Capitanio, Blandine; Idir, Mourad [Synchrotron SOLEIL, L' orme des Merisiers, BP 48, 91192 Gif sur Yvette (France); Bucourt, Samuel [Imagine Optic, 18 rue Charles de Gaulle, Orsay 91400 (France)

    2010-05-01

    Crystal sagittal focusing is known as one of the most efficient way of focusing synchrotron X-ray radiation from bending magnet sources, thus delivering increases photon flux at the sample position. To optimize the performance of a sagittaly bent crystal inside a monochromator, it is necessary to have knowledge of its radius of curvature. However, this measurement is not very easy to obtain. Even though the use of the X-ray beam is the ultimate source for optimizing the system, it is still necessary to have a prior knowledge of the radius of curvature as a function of the motor bender positions to avoid any catastrophic failure. In this paper, we describe a simple, efficient and accurate method of measuring the radius of curvature of sagitally bent monochromator crystals at several bending magnet beamlines at synchrotron SOLEIL. To optimize the crystal bending inside these monochromators, we used a Shack-Hartmann sensor (HP 26) developed by the Imagine Optic Company (Orsay/France). This high accuracy two-dimensional metrology tool was originally designed to be installed on a Long Trace Profiler translation stage to measure the mirrors profiles. During a period where the SOLEIL synchrotron was in shutdown, this instrument was directly mounted inside the monochromator so that the radius of curvature could be measured in-situ. This method allows us to optimize the curvature and eliminate twist before bending strongly the crystal below radii of curvature of less than 2 m. The second step in the optimization process was to use the X-ray beam for the final adjustments of the bending system, where X-ray images are then used to analyse the residual defaults of the system. Using SpotX, a ray-tracing simulation tool, these errors can be fully analysed and a fully optimized system can then be obtained. Overall, five beamlines at synchrotron SOLEIL have used in this method to optimize their monochromators.

  14. The Nature of the Idealized Triple Bonds Between Principal Elements and the σ Origins of Trans-Bent Geometries-A Valence Bond Study.

    Science.gov (United States)

    Ploshnik, Elina; Danovich, David; Hiberty, Philippe C; Shaik, Sason

    2011-04-12

    We describe herein a valence bond (VB) study of 27 triply bonded molecules of the general type X≡Y, where X and Y are main element atoms/fragments from groups 13-15 in the periodic table. The following conclusions were derived from the computational data: (a) Single π-bond and double π-bond energies for the entire set correlate with the "molecular electronegativity", which is the sum of the X and Y electronegativites for X≡Y. The correlation with the molecular electronegativity establishes a simple rule of periodicity: π-bonding strength generally increases from left to right in a period and decreases down a column in the periodic table. (b) The σ frame invariably prefers trans bending, while π-bonding gets destabilized and opposes the trans distortion. In HC≡CH, the π-bonding destabilization overrides the propensity of the σ frame to distort, while in the higher row molecules, the σ frame wins out and establishes trans-bent molecules with 2(1)/2 bonds, in accord with recent experimental evidence based on solid state (29)Si NMR of the Sekiguchi compound. Thus, in the trans-bent molecules "less bonds pay more". (c) All of the π bonds show significant bonding contributions from the resonance energy due to covalent-ionic mixing. This quantity is shown to correlate linearly with the corresponding "molecular electronegativity" and to reflect the mechanism required to satisfy the equilibrium condition for the bond. The π bonds for molecules possessing high molecular electronegativity are charge-shift bonds, wherein bonding is dominated by the resonance energy of the covalent and ionic forms, rather than by either form by itself.

  15. Ensamble de crustáceos bentónicos en un lago salino tropical Benthic crustaceans assemblage in a tropical, saline lake

    Directory of Open Access Journals (Sweden)

    Ma. del Carmen Hernández

    2010-10-01

    Full Text Available El presente trabajo reconoce la composición, estructura y distribución espacial del ensamble de crustáceos bentónicos de Alchichica, un lago salino tropical ubicado en el extremo oriental del altiplano mexicano. El lago presenta una riqueza taxonómica de crustáceos bentónicos compuesta por 1 anfípodo (Hyalella azteca, 1 isópodo (Caecidotea williamsi y 2 ostrácodos (Limnocythere inopinata y Candona sp.. Comparada con otros lagos tropicales, la riqueza de especies es reducida. A pesar de lo anterior, es importante mencionar el grado elevado de endemismo representado por C. williamsi, recientemente descrita para el lago Alchichica; adicionalmente, es factible que tanto Candona como H. azteca sean especies nuevas y endémicas del lago. Los crustáceos bentónicos se distribuyen desde la zona litoral hasta la zona más profunda del lago (62 m con abundancias y riqueza taxonómica variables. Los ostrácodos fueron los crustáceos que con mayor frecuencia se recolectaron en el lago, en la zona litoral, en el talud, y en la zona profunda de la que son habitantes exclusivos. Los anfípodos constituyeron el segundo grupo en abundancia de la zona litoral y talud y estuvieron ausentes en la zona profunda. Los isópodos sólo se encuentran asociados a los depósitos de tufa, hábitat característico del lago que se extiende a lo largo del talud, por lo que con las técnicas de muestreo tradicional empleadas en el presente estudio no fueron capturados. En este ensamble de crustáceos predominan las especies de desarrollo directo y con posiciones tróficas que incluyen componentes herbívoros (H. azteca, omnívoros (C. williamsi y bacterívoros (L. inopinata y Candona sp..This work acknowledges the composition, structure and spatial distribution of the benthic crustaceans assemblage of Alchichica, a tropical saline lake located in the easternmost portion of the Mexican highlands. The benthic crustaceans' assemblage was comprised by 1 amphipod

  16. Invertebrados bentônicos: relação entre estrutura da fauna e características do mesohabitat

    Directory of Open Access Journals (Sweden)

    Virginia Sanches Uieda

    2016-06-01

    Full Text Available Em ecossistemas lóticos é comum a formação de diferentes mesohabitats intercalados ao longo do rio, como poções, corredeiras e rápidos, frequentemente acompanhados de alterações na estrutura da fauna bentônica associada. No trabalho analisamos a fauna de invertebrados bentônicos em rápidos e corredeiras de um trecho de serra do Rio Capivara (Bacia do Médio Rio Tietê. A análise das características ambientais e a coleta da fauna foram realizadas em três corredeiras e três rápidos, em um mês da estação chuvosa (cinco réplicas de cada. Os mesohabitats se diferenciaram quanto ao maior porcentual de blocos nos rápidos e maiores valores de profundidade, correnteza e porcentual de matacões nas corredeiras. Do total de 57 Unidades Taxonômicas Operacionais (UTO's amostradas, 75% foram comuns aos dois mesohabitats (Similaridade de Morisita = 0,86. Quando analisado o porcentual de abundância, a similaridade espacial se manteve e dois grupos se sobressaíram em abundância: Hexapoda (>80%, sendo a maioria Ephemeroptera, Diptera e Trichoptera e Annelida (10%. As análises exploratórias (cluster e NMDS também apontaram para uma elevada similaridade espacial, porém os resultados da Análise de Similaridade (ANOSIM indicaram uma diferença significativa entre os mesohabitats (p<0,1%, seja analisando o total de UTO's ou retirando as UTO's raras. Cinco grupos tiveram uma maior contribuição para a média de dissimilaridade entre os mesohabitats: Simulium e Baetodes mais abundantes nas corredeiras, Traveryphes, Hagenulopsis e Macrelmis nos rápidos. Assim, os resultados da ANOSIM salientaram a importância do refinamento na identificação para a interpretação mais precisa acerca da relação entre a fauna e a estrutura do habitat.

  17. 不对称弯曲形液晶的合成与性能研究%Synthesis and property of unsymmetric bent-core liquid crystals

    Institute of Scientific and Technical Information of China (English)

    毛志鹏; 游红军; 张智勇; 王坤; 申烦

    2015-01-01

    Three novel bent-core liquid crystal compounds (8, 9a and 9b) were prepared with a central bent core based on 2,5-disubstitueted-1,3,4-oxadiazole,ester group bridge (-coo-), alkyl terminal tails, and one side wing substituted by fluorine atom .The structures of the target compounds were confirmed by IR , 1 H NMR, 13 C NMR, MS, and their transition temperatures and phase textures were investigated by using differential scanning calorimet -ric (DSC) and polarizing optical microscopy (POM).The result suggested that all target compounds had right chemical structure .All target compounds exhibited nematic phase and wide temperature range of nematic phase , and the widest range of nematic phase was 78℃.The temperature range of nematic phase of compounds 8 with later-al monofluoro-substituted benzene was more narrow than compounds 9 with lateral difluoro-substituted benzene .%以2,5-二取代-1,3,4-噁二唑为中心核,酯基(-COO-)为桥键,直链烷基为末端基团,在单侧苯环侧位上引入氟原子,设计合成了3个新型不对称弯曲形液晶化合物8,9a和9b;并通过IR,1 H NMR,13 C NMR,19 F NMR和MS对其结构进行鉴定,经差热扫描仪( DSC)和偏光显微镜( POM)测定其液晶相态。结果表明:所有目标化合物的分子结构正确,都呈现向列相态,向列相态温度范围最宽达78℃;侧位单氟苯环结构化合物(8)的向列相温度范围没有二氟苯环结构(9)的宽。

  18. O fenômeno da \\"decoada\\" no Pantanal do rio Paraguai, Corumbá/MS: alterações dos parâmetros limnológicos e efeitos sobre os macroinvertebrados bentônicos

    OpenAIRE

    Maria Helena da Silva Andrade

    2011-01-01

    Este trabalho teve como objetivo investigar a hipótese de que a decoada (alteração dos parâmetros físicos e químicos da água) é um fenômeno natural importante na estruturação da comunidade de invertebrados bentônicos do Pantanal do rio Paraguai, bem como a caracterizar a comunidade de macroinvertebrados bentônicos quanto à composição, abundância de organismos e riqueza em função das alterações ambientais provocadas pela decoada. Além disso, pretendeu-se contribuir para o conhecimento da biota...

  19. Channeling efficiency dependence on bending radius and thermal vibration amplitude of the model for the channeling of high-energy particles in straight and bent crystals implemented in Geant4

    Energy Technology Data Exchange (ETDEWEB)

    Bagli, Enrico [INFN Sezione di Ferrara, Dipartimento di Fisica e Scienze della Terra, Università di Ferrara, Via Saragat 1, 44100 Ferrara (Italy); Asai, Makoto; Dotti, Andrea [SLAC National Accelerator Laboratory, 2575 Sand Hill Rd, Menlo Park, CA 94025 (United States); Guidi, Vincenzo [INFN Sezione di Ferrara, Dipartimento di Fisica e Scienze della Terra, Università di Ferrara, Via Saragat 1, 44100 Ferrara (Italy); Verderi, Marc [Laboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS/IN2P3, F-91128 Palaiseau (France)

    2015-07-15

    Monte Carlo simulations of the interaction of particles with matter are usually done with downloadable toolkits such as Geant4. A model suitable for the implementation into Geant4 for the interaction of high-energy particles in straight and bent crystals was developed and implemented. The model relies on the continuum potential approximation. The variation of the Geant4 model for the description of the orientational effect as a function of the physical parameters for the calculation of the interplanar potential is presented. The simulations are capable of reproducing the variation of the efficiency of channeling as a function of the thermal vibration amplitude and the bending radius of a bent Si strip. The study can be useful for the simulation of the channeling effect in experiments at GeV/c energies.

  20. Temperature profiles from expendable bathythermograph (XBT) casts from the USNS SILAS BENT in the North Pacific Ocean, East China Sea, and Sea of Japan in support of the Integrated Global Ocean Services System (IGOSS) project from 13 November 1975 to 11 December 1975 (NODC Accession 7601776)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — XBT data were collected from the USNS SILAS BENT in support of the Integrated Global Ocean Services System (IGOSS) project. Data were collected by the US Navy; Naval...

  1. Secondary flow structures in the presence of Type-IV stent fractures through a bent tube model for curved arteries: Effect of circulation thresholding

    Science.gov (United States)

    Hussain, Shadman; Bulusu, Kartik V.; Plesniak, Michael W.

    2013-11-01

    A common treatment for atherosclerosis is the opening of narrowed arteries resulting from obstructive lesions by angioplasty and stent implantation to restore unrestricted blood flow. ``Type-IV'' stent fractures involve complete transverse, linear fracture of stent struts, along with displacement of the stent fragments. Experimental data pertaining to secondary flows in the presence of stents that underwent ``Type-IV'' fractures in a bent artery model under physiological inflow conditions were obtained through a two-component, two-dimensional (2C-2D) PIV technique. Concomitant stent-induced flow perturbations result in secondary flow structures with complex, multi-scale morphologies and varying size-strength characteristics. Ultimately, these flow structures may have a role to play in restenosis and progression of atherosclerotic plaque. Vortex circulation thresholds were established with the goal of resolving and tracking iso-circulation secondary flow vortical structures and their morphological changes. This allowed for a parametric evaluation and quantitative representation of secondary flow structures undergoing deformation and spatial reorganization. Supported by NSF Grant No. CBET- 0828903 and GW Center for Biomimetics and Bioinspired Engineering.

  2. Genetic Structure and Relationships among Populations of the Caspian Bent-toed Gecko, Tenuidactylus caspius (Eichwald, 1831) (Sauria:Gekkonidae) in Northern Iran

    Institute of Scientific and Technical Information of China (English)

    Vida HOJATI; Eskandar Rastegar POUYANI; Kazem PARIVAR

    2015-01-01

    The Caspian bent-toed gecko, Tenuidactylus caspius, belonging to the family Gekkonidae, is widely distributed across the northern half of Iran, especially along the southern coastal region of the Caspian Sea. It is regarded as a commensal species throughout its entire distribution. We investigated genetic variation and relationships among different populations of this species in Iran. Fragments of the mitochondrial cyt b (547 bp) and ND4 (831 bp) genes were sequenced and analyzed in 64 and 28 specimens, respectively, from 21 geographically distant localities. Cyrtopodion scabrum was used as the outgroup taxon. The data showed no significant genetic variation within the populations of T. caspius in Iran. Nevertheless, populations of Khorasan and Semnan (especially Shahrood) in northeastern Iran showed greater divergence (p-distance = 2.1%) from other Iranian populations. The low genetic variation and homogeneous structure among populations of T. caspius on either side of the Elburz Mountains suggests that this species most likely has achieved its current distribution recently and as a result of anthropogenic activities.

  3. 技术不过是工具,触动心灵更重要——访挪威Hegel主设计师Bent Holter

    Institute of Scientific and Technical Information of China (English)

    沈剑萍

    2008-01-01

    在白天鹅音响展上,当我(以下简称作“沈”)第一眼见到Hegel的创始人Bent Holter(以下简称作Bent)时,觉得他好高好瘦,与我印象中的北欧壮汉大相径庭;还很年轻,好象也就三十来岁的样子;言语不多,显得平和沉稳。但随着谈话的深入,让我逐渐了解Bent的另一面:他已经42岁了,真的看不出来;虽然他很斯文,但他同时也是一位很狂热的吉他手,玩的还是木吉他,足足有14年的资历;为人低调、

  4. Focusing bent perfect-crystal neutron monochromator a key to high-resolution stress/strain measurement studies of polycrystalline materials

    CERN Document Server

    Ono, M; Harjo, S; Saroun, J; Yoneda, K; Sawano, J; Sakurai, Y; Kobayashi, T

    2000-01-01

    A new neutron focusing device with bent Si-single crystal has been installed at high-resolution neutron diffractometer dedicated to strain/stress investigations in polycrystalline materials and introduced into routine operation as a neutron strain scanner using reactor neutrons from supermirror guider at Kyoto University Research Reactor (KUR). Properties of the diffractometer are described on the basis of experimental results when one slab or two slabs of curved Si single crystals are employed as monochromator:i.e. 1) the luminosity 2) the absolute value of monochromatic neutrons with the Au-foil activation method, 3) beam profiles with the imaging plate method, 4) characterization of the diffractometer with alpha Fe (211) peak and its comparison with the Bragg optical prediction. It is confirmed that the FWHM of the instrumental delta d/d-profile of the peak can be less than 3*10/sup -3/ at d=1.17 A and the resolution permits us to investigate both the macro- and microstrains with good luminosity. The lumin...

  5. On some liquid crystalline phases exhibited by compounds made of bent-core molecules and their mixtures with rod-like molecules

    Indian Academy of Sciences (India)

    R Pratibha; N V Madhusudana; B K Sadashiva

    2003-08-01

    In most homologous series of compounds made of bent-core (BC) molecules, the B2, B1 and B6 phases occur as the chain length decreases. We have studied binary mixtures of the compound 1,3-phenylene bis[4-(3-methylbenzoyloxy)]4'--dodecylbiphenyl 4'-carboxylate (BC12) which exhibits the B2 phase with the compound 4-biphenylyl 4''--undecyloxybenzoate (BO11) made of rod-like (R) molecules. We find the above sequence of occurrence of the B phases with increasing concentration of BO11. In this paper we describe the physical origin for the formation of these phases in both pure compounds and in the mixtures. We have also found the occurrence of the biaxial smectic A phase when the BO11 concentration is increased to 87–95.5 mol%. We also report on another binary system composed of BC12 and 4--octyloxy 4'- cyanobiphenyl (8OCB) made of R molecules. This system exhibits the biaxial smectic A phase down to 30°C. Using polarized infrared spectroscopy we find that the mutual orientation of the R and BC molecules in the SmAdb liquid crystal is such that the arrow axes of the BC molecules are along the layer normal of the partial bilayer smectic structure formed by the rods. We also describe unusual growth patterns obtained when the nematic phase transforms to the SmAdb phase in a mixture with 24 mol% of BC12.

  6. Detection of multi-scale secondary flow structures using anisotropic 2D Ricker wavelets in a bent tube model for curved arteries

    Science.gov (United States)

    Plesniak, Daniel H.; Bulusu, Kartik V.; Plesniak, Michael W.

    2012-11-01

    Interpretation of complex flow patterns observed in this study of a model curved artery required characterization of multiple, low-circulation secondary flow structures that were observed during the late systolic deceleration and diastolic phases under physiological inflow conditions. Phase-locked, planar vorticity PIV data were acquired at various cross-sectional locations of the 180-degree bent tube model. High circulation, deformed Dean- and Lyne-type vortices were observed during early stages of deceleration, while several smaller scale, highly deformed, low-circulation vortical patterns appeared in the core and near-wall regions during late systolic deceleration and diastolic phases. Due to the multiplicity of vortical scales and shapes, anisotropic 2D Ricker wavelets were used for coherent structure detection in a continuous wavelet transform algorithm (PIVlet 1.2). Our bio-inspired study is geared towards understanding whether optimizing the shape of the wavelet kernel will enable better resolution of several low-circulation, multi-scale secondary flow morphologies and whether new insights into the dynamics of arterial secondary flow structures can accordingly be gained. Supported by the National Science Foundation, Grant No. CBET-0828903 and GW Center for Biomimetics and Bioinspired Engineering (COBRE).

  7. A regime map for secondary flow structures under physiological and multi-harmonic inflow through a bent tube model for curved arteries

    Science.gov (United States)

    Callahan, Shannon M.; Caldwell, Kirin; Bulusu, Kartik V.; Plesniak, Michael W.

    2012-11-01

    Secondary flow structures are known to affect wall shear stress, which is closely related to atherogenesis and drug particle deposition. A regime map provides a framework to examine phase-wise variations in secondary flow structures under physiological and multi-harmonic inflow waveforms under conditions of a fixed Womersley number (4.2) and curvature ratio (1/7). Experimental PIV data were acquired at the 90-degree location in a 180-degree curved test section of a bent tube model for curved arteries using a blood analog working fluid. Coherent structure detection was performed using a continuous wavelet transform algorithm (PIVlet 1.2) and further analysis was carried out by grouping similar secondary flow structures at a fixed secondary Reynolds numbers. Phase-locked, planar vorticity fields over one period of inflow waveform revealed size, structure and strength similarities in secondary flow morphologies during the acceleration and deceleration phases. The utility of the new regime map lies in the a priori identification of pulsatile secondary flow structures, eliminating the need for exhaustive experimentation or computing, requiring only flow rate measurements that are easily acquired under clinical conditions. Supported by the National Science Foundation, Grant No. CBET-0828903 and GW Center for Biomimetics and Bioinspired Engineering (COBRE).

  8. Ytterbocenes as one- and two-electron reductants in their reactions with diazadienes: YbIII mixed-ligand bent-sandwich complexes containing a dianion of diazabutadiene.

    Science.gov (United States)

    Trifonov, Alexander A; Borovkov, Ivan A; Fedorova, Elena A; Fukin, Georgii K; Larionova, Joulia; Druzhkov, Nikolai O; Cherkasov, Vladimir K

    2007-01-01

    Ytterbocene [Yb(C(5)MeH(4))(2)(thf)(2)] reacts with diazabutadiene 2,6-iPr(2)C(6)H(3)-N=CH-CH=N-C(6)H(3)iPr(2)-2,6 (DAD) as a one-electron reductant to afford a bis(cyclopentadienyl) Yb(III) derivative containing a DAD radical anion [Yb(C(5)MeH(4))(2)(dad(-.))]. However, ytterbocenes [YbCp*(2)(thf)(2)] (Cp*=C(5)Me(5), C(5)Me(4)H) coordinated by sterically demanding cyclopentadienyl ligands act as two-electron reductants in their reactions with DAD. These reactions occur by abstraction of one Cp* ring and result in the formation of novel Yb(III) mixed-ligand bent-sandwich complexes, [YbCp*(dad)(thf)], in which the dianion of DAD has an uncommon terminal eta(4)-coordination to the ytterbium atom. The variable-temperature magnetic measurements of complex [Yb(C(5)Me(5))(dad)(thf)] suggest the existence of redox tautomerism for this compound.

  9. Polar Order and Symmetry Breaking at the Boundary between Bent-Core and Rodlike Molecular Forms: When 4-Cyanoresorcinol Meets the Carbosilane End Group.

    Science.gov (United States)

    Westphal, Eduard; Gallardo, Hugo; Caramori, Giovanni Finoto; Sebastián, Nerea; Tamba, Maria-Gabriela; Eremin, Alexey; Kawauchi, Susumu; Prehm, Marko; Tschierske, Carsten

    2016-06-01

    Two isomeric achiral bent-core liquid crystals involving a 4-cyanoresorcinol core and containing a carbosilane unit as nanosegregating segment were synthesized and were shown to form ferroelectric liquid-crystalline phases. Inversion of the direction of one of the COO groups in these molecules leads to a distinct distribution of the electrostatic potential along the surface of the molecule and to a strong change of the molecular dipole moments. Thus, a distinct degree of segregation of the carbosilane units and consequent modification of the phase structure and coherence length of polar order result. For the compound with larger dipole moment (CN1) segregation of the carbosilane units is suppressed, and this compound forms paraelectric SmA and SmC phases; polar order is only achieved after transition to a new LC phase, namely, the ferroelectric leaning phase (SmCLs PS ) with the unique feature that tilt direction and polar direction coincide. The isomeric compound CN2 with a smaller dipole moment forms separate layers of the carbosilane groups and shows a randomized polar SmA phase (SmAPAR ) and ferroelectric polydomain SmCs PS phases with orthogonal combination of tilt and polar direction and much higher polarizations. Thus, surprisingly, the compound with the smaller molecular dipole moment shows increased polar order in the LC phases. Besides ferroelectricity, mirror-symmetry breaking with formation of a conglomerate of macroscopic chiral domains was observed in one of the SmC phases of CN1. These investigations contribute to the general understanding of the development of polar order and chirality in soft matter.

  10. Relationship between architecture, filament breakage and critical current decay in Nb3Sn composite wires repeatedly in-plane bent at room temperature

    Science.gov (United States)

    Badica, P.; Awaji, S.; Oguro, H.; Nishijima, G.; Watanabe, K.

    2006-04-01

    Six Nb3Sn composite wires with different architectures ('central and near-the-edge reinforcement') were repeatedly in-plane bent at room temperature (in-plane 'pre-bending'). Breakage behaviour was revealed from scanning electron microscopy observations by semi-quantitative analysis of the filament crack formation and evolution. Cracks are formed in the transversal and longitudinal directions. Transversal cracks show some tolerance to the applied bending strain due to the fact that filaments are composite materials; residual Nb core can arrest development of a partial transversal crack initiated in the Nb3Sn outer part of the filament. Together with the density of cracks C and the evolution of this parameter with pre-bending strain, ɛpb, in different regions of the wire, R-ɛpb curves are important to understand breakage behaviour of the wires. R is the ratio (number of full transversal cracks)/(number of full transversal cracks + number of partial transversal cracks). Parameters C and R allow us to reveal and satisfactorily understand the wire architecture—breakage—critical current decay relationship when pre-bending treatment is applied. As a consequence, breakage criteria necessary to minimize Ic decay were defined and the positive influence of the reinforcement in preventing breakage was observed. It was also found that, in this regard, more Nb in the CuNb reinforcement, for the investigated wires, is better, if the heat treatment for the wire synthesis is performed at 670 °C for 96 h. A different heat treatment, 650 °C for 240 h, is less efficient in preventing filament breakage. Our results suggest the possibility of control and improvement of the breakage susceptibility of the filaments in the wires and, hence, of the bending Ic decay, through the wise design of the wire architecture (i.e. by correlating design with the choice of composing materials and heat treatments).

  11. Tuned synthesis of two coordination polymers of Cd(II) using substituted bent 3-pyridyl linker and succinate: structures and their applications in anion exchange and sorption properties.

    Science.gov (United States)

    Maity, Dilip Kumar; Bhattacharya, Biswajit; Halder, Arijit; Ghoshal, Debajyoti

    2015-12-28

    Two new Cd(II) coordination polymers, namely [Cd(3-bpdh)2(ClO4)2]n (1) and {[Cd(3-bpdh)(suc)(H2O)]·3(H2O)}n (2), have been synthesized using a substituted bent N,N'-donor ligand 2,5-bis-(3-pyridyl)-3,4-diaza-2,4-hexadiene (3-bpdh) and aliphatic dicarboxylate disodium succinate (suc) with Cd(II) perchlorate salts at room temperature by a slow diffusion technique for the exploration of our previous reported work. Both the structures were determined by single-crystal X-ray diffraction analysis and also by other physicochemical methods. Structure analysis revealed that complex 1 is a 1D chain structure containing coordinated perchlorate with a metal centre, and complex 2 shows a porous 3D framework with encapsulation of lattice water molecules into the void along the crystallographic a-axis. The PXRD study shows the bulk purity of both the complexes and TGA analysis of 2 exhibits that the structure is thermally stable up to 250 °C. Complex 1 shows a nice anion exchange property with replacement of weakly coordinated perchlorate with the inclusion of new anions; and the anion exchanged solids were characterised by FT-IR, PXRD and photoluminescence properties. The desolvated framework of 2 exhibits sorption of CO2 and water vapor and surface adsorption of N2 corroborating with the nature of the pore environment present in 2. The photoluminescence study has been also done for both complexes in the solid state which exhibits ligand based emissions at room temperature.

  12. On bent and semi-bent quadratic Boolean functions

    DEFF Research Database (Denmark)

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

    2005-01-01

    The maximum-length sequences, also called m-sequences, have received a lot of attention since the late 1960s. In terms of linear-feedback shift register (LFSR) synthesis they are usually generated by certain power polynomials over a finite field and in addition are characterized by a low cross co...

  13. ELASTIC EARTHQUAKE RESPONSE ANALYSIS OF STEEL FRAME-BENT STRUCTURES OF MAIN BUILDINGS FOR LARGE THERMAL POWER PLANT%大型火电厂钢结构主厂房弹性地震反应分析

    Institute of Scientific and Technical Information of China (English)

    薛建阳; 梁炯丰; 彭修宁; 温永强

    2012-01-01

    The steel frame-bent structure is the main load-supporting structure in thermal power plants of China, whose structural quality and rigidity are distributed non-uniformly. It is particularly necessary to research earthquake resistant behavior of this structure. The time history response analysis method was used to study the dynamic properties, the interlayer deformation and the interlayer shear of steel frame-bent structures of main buildings for large thermal power plant. The results showed that there were many weak parts in the horizontal frame-bent and longitudinal frame-supporting structures, which must be strengthened when designed. The space model should be used to consider the effect of torsion in structural calculation and analysis.%钢框排架结构是我国火电厂主厂房的主要结构形式之一,但因其结构质量、刚度分布不均匀,所以对它的抗震性能研究尤为必要。采用弹性时程分析方法对大型火电厂钢框排架主厂房进行抗震分析,研究该类结构的动力特性、层间变形和层剪力等。计算结果表明:主厂房横向框排架和纵向框架-支撑结构存在较多的薄弱部位,计算分析应采用考虑扭转效应的空间模型。

  14. Efeito de metais Cobre (Cu e Zinco (Zn sobre a comunidade de macroinvertebrados bentônicos em riachos do sul do Brasil = The effect of metals (Cu and Zn on the benthic macroinvertebrate community in streams in southern Brazil

    Directory of Open Access Journals (Sweden)

    Silvia Vendruscolo Milesi

    2008-07-01

    Full Text Available O objetivo deste estudo foi avaliar os efeitos de metais (Cu e Zn sobre a comunidade de macroinverterados bentônicos. Foram amostrados, trimestralmente, entre setembro de 2006 e junho de 2007, organismos e água em oito trechos de riachos de duas bacias hidrográficas influenciadas por urbanização e agricultura. Foram estimados os valores de densidade de organismos, riqueza taxonômica e diversidade de Shannon. Para avaliação dos dados, foram utilizados testes de variância e regressão linear simples. Os resultados demonstraram variabilidade das concentrações dos metais e da macrofauna entre as estações do ano e riachos estudados. O metal Cobre (Cu apresentou influência apenas sobre a densidade Chironomidae e o metal Zinco (Zn apresentou efeito sobre a densidade total da macrofauna bentônica e de Chironomidae. Nenhum dos metais apresentou efeitos sobre ariqueza e diversidade de macroinvertebrados. Os resultados indicam potencial bioindicador da comunidade bentônica na avaliação da qualidade integrada do ambiente.The aim of this study was to evaluate the effect of metals (Cu and Zn on the benthic macroinvertebrate community. The organismsand water were collected quarterly between September 2006 and June 2007, in eight sites in streams of two hydrographic basins, influenced by urbanization and agriculture. The values of organism density, taxonomic richness and the Shannon diversity index were calculated. For data evaluation, tests of variance and simple linear regression were used. The results showed variability in the metal concentration and benthic community among seasons and studied streams. Cu showed influence only on Chironomidae density. Zn demonstrated effect on the benthic community and Chironomidae density. None of the metals presented effect on the macroinvertebrate richness and diversity. The results indicate a bioindicatorpotential of the benthic community in the evaluation of integral quality of the environment.

  15. Diversidade de habitats físicos e sua relação com macroinvertebrados bentônicos em reservatórios urbanos em Minas Gerais

    Directory of Open Access Journals (Sweden)

    Joseline Molozzi

    2011-09-01

    Full Text Available Foram avaliados os efeitos da estrutura física de habitats em comunidades de macroinvertebrados bentônicos em três reservatórios: Serra Azul (SA, Vargem das Flores (FV e Ibirité (IB. Mensurações de variáveis físicas e químicas e comunidade bentônica foram realizadas em 30 estações de amostragem em cada reservatório. Em SA, foram coletados 12 táxons com predomínio de Melanoides tuberculatus Müller, 1774 (15,2% e Chaoboridae (63,8%. Em VF foram coletados 11 táxons sendo M. tuberculatus (34,2% e Oligochaeta (33,6% os dominantes. Em IB foram coletados 7 táxons com domínio de M. tuberculatus (91,2% e Chaoboridae (6,27%. Em Serra Azul foi observada influência significativa do sub-bosque arbustivo e do ângulo de inclinação do barranco. Nos reservatórios de Ibirité e Vargem das Flores as variáveis significativas foram cobertura do solo, influência humana e macrófitas aquáticas. Concluímos que as ações humanas reduzem a cobertura da vegetação terrestre e a complexidade de habitats físicos na região litorâneos dos reservatórios, levando a uma redução na qualidade de água. Essas mudanças, por sua vez, reduzem a riqueza taxonômica dos macroinvertebrados bentônicos.

  16. Algas marinas bentónicas de la costa noroccidental de Guerrero, México Benthic marine algae of the west coast of Guerrero, Mexico

    Directory of Open Access Journals (Sweden)

    Luz Elena Mateo-Cid

    2012-12-01

    Full Text Available Se presentan los resultados de un estudio sobre algas marinas bentónicas en 7 localidades de la costa noroccidental de Guerrero, México. Se determinó la presencia de 163 especies de algas marinas. Se identificaron 17 especies de Cyanobacteria, 93 Rhodophyta, 28 Chlorophyta y 25 de Heterokontophyta. Se citan 54 registros nuevos para el litoral de Guerrero, 2 también nuevos, Myrionema strangulans Greville y Acrochaete ramosa (N.L.Gardner O'Kelly para la costa del Pacífico. Cada especie se acompaña de datos sobre su distribución en el área de estudio, su estado reproductivo, nivel de marea, hábitat, observaciones, epifitismo y número de herbario o de recolección. Se comparó la riqueza específica entre la estación climática de lluvias y la de secas. La división Rhodophyta dominó en términos de diversidad en relación con las 3 divisiones restantes. La ficoflora de la costa noroccidental de Guerrero es de afinidad tropical y más diversa en la época de secas.We present results on the study on benthic marine algae in 7 localities from the west coast of Guerrero, Mexico. We report 163 species: 17 Cyanobacteria, 93 Rhodophyta, 28 Chlorophyta and 25 Heterokontophyta. Fifty four are new records for Guerrero; while Myrionema strangulans Greville and Acrochaete ramosa (N.L.Gardner O'Kelly are new to the Pacific coast of Mexico. Each species includes data on its distribution, reproductive stages, tidal level, facies, epiphytism and herbarium's number. Species diversity was compared for 2 different climatic seasons. The Rhodophyta are dominant in terms of diversity in relation to the other groups. The algal flora of the northwest coast of Guerrero is tropical and the greatest diversity was found during dry seasons.

  17. Macroinvertebrados bentónicos como indicadores de la calidad de agua en la microcuenca San Alberto, Oxapampa, Perú

    Directory of Open Access Journals (Sweden)

    Stefany Salcedo Gustavson

    2013-12-01

    Full Text Available Objetivos: Evaluar la biodiversidad de macroinvertebrados y la calidad ecológica de la microcuenca San Alberto (provincia de Oxapampa, Pasco de abril a julio de 2013. Métodos: El muestreo fue realizado en tres zonas de la microcuenca San Alberto (cuenca alta, media y baja. En los tres sitios fueron colectados macroinvertebrados bentónicos en piedra y arena. Luego se estimaron: el índice biótico andino (IBA, de hábitat fluvial (IHF, de calidad de vegetación de ribera andina (QBRAnd y de estado ecológico (ECOSTRIAND. Se evaluaron parámetros fisicoquímicos, nutrientes y metales en el agua. Resultados: Se registraron un total de 123 taxones de 47 familias (101 taxones en la cuenca alta, 77 en la cuenca media y 55 en la cuenca baja. La mayor abundancia de macroinvertebrados se presentó en la cuenca media. El IBA resultó ser de “muy buena” calidad para la cuenca alta, media y baja, pero al combinarse este índice con el QBR-And, para elaborar el Índice ECOSTRIAND, se observó el estado ecológico de las cuencas alta y media fueron de “muy buena” calidad y de la cuenca baja fue “regular”. El método de muestreo de limpieza de piedras fue el que permitió colectar la mayor cantidad de taxones. Las mejores condiciones de hábitat fluvial, de vegetación ribereña y de estado ecológico, tras la aplicación de los índices IHF, QBR-And y ECOSTRIAND, se encuentran en la cuenca alta. Conclusiones: Los resultados indican que la diferencia de calidad de hábitat ribereño y fluvial así como de conductividad, sólidos disueltos y nitratos influyen negativamente sobre la calidad del agua, y ésta, sobre la comunidad de macroinvertebrados. Las familias reportadas como sensibles a la contaminación (Leptophlebiidae, Oligoneuriidae, Perlidae, Anomalopsychidae, Calamoceratidae, Helicopsychidae, Odontoceridae, Blephariceridae mostraron ser bioindicadores de calidad de agua para la microcuenca.

  18. Clorofíceas marinhas bentônicas da Praia de Serrambi, Pernambuco, Brasil Benthic marine Chlorophyceae from Serrambi Beach, Pernambuco, Brazil

    Directory of Open Access Journals (Sweden)

    Sônia Maria Barreto Pereira

    1998-04-01

    Full Text Available É apresentado o levantamento florístico sobre as clorofíceas marinhas bentônicas encontradas na Praia de Serrambi, litoral Sul do Estado de Pernambuco. O material estudado foi coletado em três estações, as quais foram visitadas mensalmente durante o período de abril de 1986 a setembro de 1987. As clorofíceas foram representadas na flora local por 39 espécies, três variedades e uma forma, pertencentes às ordens Ulotrichales, Ulvales, Siphonocladales, Cladophorales, Caulerpales e Dasycladales. Acetabularia calyculus Quoy & Gaimard. In Freycinet, Bryopsis pennata Lamouroux, Bryopsis plumosa (Hudson C. Agardh, Caulerpa ambigua Okamura, Caulerpa serrulata (Forsskål J. Agardh emend Børgesen, Chaetomorpha brachygona Harvey, Cladophora coelothrix Kützing, Cladophoropsis membranacea (C. Agardh Børgesen, Codium intertextum Collins & Hervey, Ernodesmis verticillata (Kützing Børgesen são novas referências para a flora do litoral de Pernambuco. Pringsheimiella scutata (Reinke von Höhnel ex Marchewianka o é também para o litoral continental do Brasil. Halimeda opuntia (L. Lamouroux foi hospedeira de maior número de epífitas, enquanto Bryopsis plumosa, quando epífita, foi a que cresceu sobre maior número de hospedeiros.This survey presents studies about benthics marine chlorophyceae found in the Serrambi Beach, South coast of Pernambuco. The material studied was collected in three stations, which were visited monthly during the period from April, 1986 to September, 1987. The chlorophyceae were represented in this flora by 39 species, three varieties and one form, from orders Ulotrichales, Ulvales, Siphonocladales, Cladophorales, Caulerpales and Dasycladales. Acetabularia calyculus Quoy & Gaimard. In Freycinet, Bryopsis pennata Lamouroux, Bryopsis plumosa (Hudson C. Agardh, Caulerpa ambigua Okamura, Caulerpa serrulata (Forsskål J. Agardh emend Børgesen, Chaetomorpha brachygona Harvey, Cladophora coelothrix Kützing, Cladophoropsis

  19. Estrutura da Comunidade de Invertebrados Bentônicos do Rio Piranhas-Assu, Rio Grande do Norte, Nordeste do Brasil

    Directory of Open Access Journals (Sweden)

    Jansen Fernandes Medeiros

    2008-12-01

    Full Text Available Esse trabalho teve como objetivo conhecer os invertebrados bentônicos, bem como caracterizar os grupos tróficos funcionais existentes no rio Piranhas-Assu, município de Alto do Rodrigues, Rio Grande do Norte. As coletas foram realizadas nos meses de maio (chuva, julho e setembro (seca de 2002, em trechos diferentes do rio. Foi medida a velocidade da correnteza, a largura, profundidade do rio e temperatura da água. Foram coletados 3525 indivíduos de Insecta e outras classes (Malacostraca, Gastropoda, Bivalvia, Arachnida, Ostracoda e Copepoda. A maior abundância da classe Insecta ocorreu no mês de setembro (seca. A vazão apresentou correlação com a abundância com na Classe Insecta, já a velocidade superficial da água para outras classes. Entre os Insecta observou-se uma maior abundância de predadores, seguida dos coletores, já para as outras classes os raspadores foram mais abundantes.Structure of benthic invertebrate’s community with focus in the aquatic insects of the Piranhas-Assu river, State of Rio Grande do Norte, Northeast, BrazilAbstract. The aim of this work was to verify the benthonic invertebrates, and to identify the functional trophic groups that exist in the Piranhas-Assu, in Alto do Rodrigues municipality, Rio Grande do Norte State. The samples were carried taken on May (rain season, July and September (dry season from 2002, in different sites in the river. The measurements of water speed, wide, temperature and river deep where made. It was collected 3525 individuals of Insecta and other classes (Malacostraca, Gastropoda, Bivalvia, Arachnida, Ostracoda and Copepoda. Insecta showed a higher abundance in September (dry season. The river discharge showed significant correlation with Insecta classe abundance, and the superficial water speed had correlation with other classes. The insects showed a highest abundance of predators, followed by collectors, in the other classes, the scrappers were the most abundant.

  20. Bent u klaar voor burgerinitiatieven?

    NARCIS (Netherlands)

    Kerstholt, J.H.

    2014-01-01

    Wat motiveert burgers om iets voor hun omgeving te doen? En wat is de motivatie van gemeenten om burgerparticipatie in te zetten? Met José Kerstholt terug naar de basis om burgerparticipatie en maatschappelijke initiatieven effectief te benutten.

  1. 基于IDA方法的框排架结构抗震性能分析%Seismic performance analysis based on Incremental dynamic analysis for frame-bent structure

    Institute of Scientific and Technical Information of China (English)

    牛帅; 朱佳宁

    2012-01-01

    the main powerhouse belongs to frame-bent structure style, is of irregular shape, complicated force paths. In strong earthquake, it easily deforms and even collapses to cause much damage. Therefore, the seismic capability must be known. According to incremental dynamical analysis method, 10 earthquake waves are chosen in nonlinear time-history a-nalysis of frame-bent structure. Through statistical analysis of IDA curves obtained, the IDA curve based on the probability of each floor and the whole structure can be obtained to make a judgment for the performance. Seismic capability of main powerhouse is more than demand, but its coal scuttle beam is vulnerable, strengthening is needed in design process.%基于逐步增量弹塑性时程方法,选择了10条地震波对火电厂主厂房框排架结构进行非线性时程分析,得到了相关指标的IDA曲线簇,并进行统计分析,最终得到了以概率为基础的框排架各层以及整体IDA曲线,以此对抗震性能进行评价.主厂房框排架结构抗震能力具有较大的富余度,但煤斗大梁处是结构的薄弱环节,设计时应注意加强.

  2. 对数螺旋型劳厄弯晶的X射线单色成像应用%Logarithmic Spiral Bent Laue Crystals for X-Ray Monochromatic Imaging Applications

    Institute of Scientific and Technical Information of China (English)

    毋玉芬; 肖沙里; 鲁建; 钱家渝; 刘利锋; 黄显宾

    2013-01-01

    Taking advantages of the monochromatic X-ray diffraction property of Laue crystals,an innovative use of logarithmic spiral bent Laue crystals for X-ray monochromatic imaging is investigated.According to the ray tracing method and the surface equation of the logarithmic spiral,the imaging principles and characteristics of the logarithmic spiral bent Laue crystals are studied,including the condition that the diffracted beam can be separated from the transmitted beam,the magnifications and the field of view (FOV).A logarithmic spiral bent quartz (1010) Laue crystal analyzer is developed.With the proposed crystal analyzer,the monochromatic backlight imaging experiment for the mesh grid with a diameter of 50 μm is carried out by taking an X-ray source of Cu target as the backlighter.The experimental results show that the spatial resolution of the analyzer is approximately 11.9 μm under a source diameter of 110 μm.Furthermore,the FOVs of the crystal analyzer are 22.3557 mm and 8.2602 mm in horizontal and vertical directions,respectively.%利用劳厄晶体研究了X射线的单色衍射性质,研究了对数螺旋型劳厄弯晶在等离子体X射线单色成像中的应用.根据光线追迹原理及对数螺旋线的表面方程,研究了对数螺旋型劳厄弯晶的单色成像原理,分析了单色衍射像不受透射白光X射线影响的准则,以及子午、弧矢放大倍数和单色成像视场等性能参数.研制了石英晶体(1010)对数螺旋劳厄弯晶分析器,以铜靶X射线源作为背光源,对网丝直径为50 μm的金属网格进行了单色背光成像实验.实验结果表明,当背光源尺寸为110 μm时,对数螺旋型劳厄弯晶的空间分辨力约为11.9μm,分析器在子午和弧矢方向的视场分别达到22.3557 mm和8.2602 mm.

  3. Macroinvertebrados bentônicos como indicadores de qualidade de água na Barragem Santa Bárbara, Pelotas, RS, Brasil Zoobenthics as indicators of the water quality in the Santa Bárbara Dam, Pelotas, RS, Brazil

    Directory of Open Access Journals (Sweden)

    Sérgio Renato Noguez Piedras

    2006-04-01

    Full Text Available O objetivo deste trabalho foi estudar o impacto de dois afluentes da barragem Santa Bárbara sobre o ambiente da mesma, utilizando a ocorrência de invertebrados bentônicos e características químicas da água. Durante nove meses foram realizadas coletas e análises da água e de invertebrados bentônicos nos afluentes Sanga da Barbuda e Sanga do Passo do Cunha e também no interior da bacia de acumulação da barragem. Os resultados mostram que, embora a Sanga da Barbuda e a Sanga do Passo do Cunha apresentem características químicas abaixo do recomendável, no limite aceitável pela legislação que determina os padrões de qualidade da água para abastecimento público, estes afluentes estão, ainda, sendo diluídos de forma satisfatória na bacia de acumulação da barragem. O estudo das relações entre variáveis químicas e invertebrados bentônicos mostra haver correlação significativa entre os baixos níveis de oxigênio dissolvido e a presença de Oligochaeta, sendo que o aumento do número de Oligochaeta indica uma situação de anoxia na barragem Santa Bárbara.The objective of this work was to study the impact of two tributaries from the Santa Bárbara Dam on this environment using the occurrence of zoobenthics and some water chemical characteristics. Monthly gathering and analysis from the water and zoobenthics were done during nine months in the tributaries Sanga da Barbuda and Sanga Passo do Cunha as well as in the inner part of the accumulation basin in the Santa Barbara dam. The results demonstrate that, though Sanga da Barbuda and Sanga Passo do Cunha present chemical characteristics lower than the recommended but still in the limits acceptable by the law that regulates the water quality standards for the supply, these tributaries are being diluted in a satisfactory way in the accumulation basin in the Santa Barbara dam. The study of the relations between chemical variables and zoobenthics show a significant correlation

  4. 专注线路设计,让器材还原出更真实的声音 Hegel总设计师Bent Holter媒体见面会

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    挪威Hegel是音响界的新晋品牌,其产品涉及CD机、解码器以及放大器。Hegel以务实的设计作风和旗帜鲜明的风格得到了音响发烧友们的认可,其产品也得到业界的广泛好评。由于Hegel进入中国市场的时间不长,其总设计师Bent Holter十分重视中国市场的发展,为此,于2011年5月10日来到广州昌业音响有限公司与本地影音媒体进行交流,

  5. Spontaneous and field-induced mesomorphism of a silyl-terminated bent-core liquid crystal as determined from second-harmonic generation and resonant X-ray scattering.

    Science.gov (United States)

    Folcia, C L; Ortega, J; Etxebarria, J; Rodríguez-Conde, S; Sanz-Enguita, G; Geese, K; Tschierske, C; Ponsinet, V; Barois, P; Pindak, R; Pan, LiDong; Liu, Z Q; McCoy, B K; Huang, C C

    2014-01-07

    The polarity and structure of the phases of a liquid crystal constituted by thiophene-based bent-core molecules is investigated by means of optical second-harmonic generation (SHG), and resonant and conventional X-ray diffraction. The material studied is representative of a wide family of mesogens that contain silyl groups at the ends of the chains. These bulky terminal groups have been reported to give rise to smectic phases showing ferroelectric switching. However, the analysis of the SHG signal before and after application of electric fields has allowed us to establish unambiguously that the reported ferroelectricity is not intrinsic to the material but stabilized by the cell substrates once an electric field has been applied. In addition, the results obtained from resonant X-ray diffraction indicate that virgin samples have antiferroelectric undulated synclinic smectic structures.

  6. Analysis and Study on Equivalent Length of Reinforced Concrete Bent-columns%关于钢筋混凝土排架柱等效长度的分析研究

    Institute of Scientific and Technical Information of China (English)

    潘斯

    2015-01-01

    The finite element analysis software ETABS is adopted to simulate twelve two-span reinforced concrete bent structures, and the equivalent length coefficients of side columns and middle columns are respectively calculated withh-l0method. And through the analysis and summarization of the obtained data, it shows that the height ration of the upper and lower columns is the main influencing factor of the equivalent length of bent columns. In comparison with the values of the equivalent length coefficient in Code for Design of Concrete Structures, it shows that there is a big difference between the standard value and the actual calculation results, and it is not reasonable to merge the value of the side columns and middle columns.%应用有限元分析软件ETABS对12个两跨钢筋混凝土排架结构进行模拟,采取h-l0法分别反算出边柱、中柱的等效长度系数,并对所得数据进行分析归纳,发现上下柱高度比是影响排架柱等效长度系数的主要因素。将分析所得排架柱等效长度系数与《混凝土结构设计规范》中的取值进行对比,发现规范取值和实际计算结果有较大差异,而且规范取值没有区分边柱和中柱也是不合理的。

  7. Estrutura da comunidade de macroinvertebrados bentônicos de um riacho de serra em Itatinga, São Paulo, Brasil Structure of a benthic macroinvertebrates community in a mountain stream in Itatinga, São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Ludmilla O. Ribeiro

    2005-09-01

    Full Text Available A comunidade de macroinvertebrados bentônicos de um riacho de terceira ordem foi analisada em duas estações do ano, chuvosa e seca. Substratos artificiais foram amostrados semanalmente, ao longo de 56 dias para a coleta de macroinvertebrados, nas duas estações do ano. A composição da comunidade foi caracterizada por uma baixa diversidade, ou seja, presença de muitas espécies raras e poucas espécies abundantes nas duas estações do ano. Uma alta dominância de Chironomidae (Diptera nas duas estações, seguida de Baetidae (Ephemeroptera e Ancylidae (Mollusca, respectivamente nas estações chuvosa e seca, foi característico. Os resultados obtidos reforçam a grande importância de Chironomidae na comunidade bentônica de riachos e salientam a influência da sazonalidade sobre a estruturação destes organismos.The benthic macroinvertebrates community of a third order stream was studied during the wet and dry seasons. The community was analyzed using artificial substrates sampled weekly during 56 days in each season. The community composition was characterized by low species diversity, with high number of rare species and few abundant species for both seasons. A high dominance of Chinonomidae (Diptera for both seasons, followed by Baetidae (Ephemeroptera and Ancylidae (Mollusca, respectively for the wet and dry seasons, was found. The results reinforced the high importance of Chironomidae and the seasonal effect determining the stream benthic community structure.

  8. EFFICACY OF MULLIGAN’S TWO LEG ROTATION AND BENT LEG RAISE TECHNIQUES IN HAMSTRING FLEXIBILITY IN SUBJECTS WITH ACUTE NON-SPECIFIC LOW BACK PAIN: RANDOMIZED CLINICAL TRIAL

    Directory of Open Access Journals (Sweden)

    Pratik .A. Phansopkar,

    2014-10-01

    Full Text Available Background and objectives: Adequate flexibility of the Hamstring muscles and Core muscle strength is necessary for a healthy lower back. Mulligan’s techniques are fascinating Physiotherapy approach in treatment of hamstrings tightness in NS-LBP such as Mulligan’s Bent Leg Raise (BLR technique, Limited Literature is available on the efficacies of Mulligan’s Two Leg Rotation (TLR technique in Hamstrings flexibility. The objective of the present study was to determine the effectiveness of Mulligan’s TLR and BLR in treatment of acute NS-LBP. Methods: The present randomized clinical trial was conducted among 40 subjects which included both male and female symptomatic subjects between the age of 18 to 35 years with acute NS-LBP and they were randomly allocated into 2 groups namely Group A[SWD, HMP, Mulligan’s TLR, MCE] , Group B[SWD, HMP, Mulligan’s BLR, MCE]. Pre-interventional and 7th day Post-interventional outcome measurements were taken in the form of Visual Analogue Scale (VAS, Modified Oswestry Disability Questionnaire (MODQ, Active Knee Extension (AKE Measurement, Lumbar ROM and Core muscle strength. Results: Intra-group comparison for all the outcome parameters in both the groups showed statistical significance (p<0.001. Inter group comparison for all the outcome parameters had differences but showed no statistical significance. Conclusion: Mulligan’s Two Leg Rotation and Bent Leg Raise techniques are effective in increasing the hamstrings flexibility in subjects with acute non specific low back pain in terms of pain, range of motion and functional disability.

  9. Effects of different fertilization treatments on winter survival rate of bent grass%不同施肥处理对匍匐翦股颖越冬性能的影响

    Institute of Scientific and Technical Information of China (English)

    王亚静; 孙吉雄; 张香运; 刘文序

    2011-01-01

    试验研究了诺维信生物复合肥分别与雷力果岭肥、尿素、富利禾鸡粪肥以不同比例配合施用对匍匐翦股颖(Agrostis stolonifera)绿期、地下生物量、密度及越冬率指标的影响,以期为高尔夫球场果岭秋季施肥提供参考。结果表明:各施肥处理均能促进草坪草初期生长,延长草坪绿期,诺维信:雷力(2:1)配合使用全年绿期最长为303d,且与诺维信:鸡粪肥(2:1)的绿期和越冬率显著高于其他处理(P〈0.05);地下生物量诺维信:雷力(1:2)显著高于其他处理(P〈0.05);秋季诺维信生物复合肥与尿素按不同比例配合施用草坪密度大,显著高于其他处理(P〈0.05),导致草坪徒长,枯草层增厚,延迟返青。综合各个指标,诺维信生物复合肥与雷力果岭专用肥配合施用,匍匐翦股颖越冬效果较好。%This experiment was studied the effects of the different mixture proportion between Novozymes Biological Fertilizer and other fertilizers(Lei Li Special Fertilizer, Urea and poultry fertilizer)on green period, underground biomass,density and winter survival rate of bent grass in order to provide some references for fertilizer management on putting green in autumn. The results showed that all the fertilization treatments promoted growth of the bent grass at early stage, and prolong its green period as well. The mixing proportion of Novozymes:Lei Li with 2 : 1 could prolong green period to 300 days. The proportion of Novozymes:Poultry Fertilizer with 2 : 1 had significant effect on green period and winter survival rate than other treatments(P〈0.05). The underground biomass under the proportion of Novozymes:Lei Li with 1 : 2 was higher than other treatments(P〈0.05). The treatment of Novozymes combined with Urea in autumn significantly improved density of putting green(P〈0.05)but it led to grass overgrowing and thick

  10. 错位六弯叶桨在假塑性流体中的混沌搅拌特性%Chaotic agitation characteristics of shifted 6-bent-blade impeller in pseudoplastic fluid

    Institute of Scientific and Technical Information of China (English)

    栾德玉; 周慎杰; 陈颂英; 楚树坡

    2011-01-01

    Based on the chaotic mixing theory, a novel impeller with shifted 6-bent-blade was proposed for destroying the mixed isolation region of laminar flow field. Computational fluid dynamics ( CFD) method was applied to the study of 3D flow field driven by a 6-bent-blade turbine (6BT) and a shifted 6-bent-blade turbine (6SBT) respectively in the agitation of xanthan gum. The flow pattern, mean velocity distribution and power consumption in stirred tank with two different impellers were extensively analyzed and compared. The results show that the values of numerical simulation and the experimental measurement of power consumption are in good agreement, and the critical Reynolds number of 6SBT in laminar flow is 20. The asymmetric structure in flow field of 6SBT can destroy mixed isolation region, and enlarge the stirring range. The improvement effect of laminar flow field performance strengthens, the average shear rate increases, and it has energy-saving effect as Reynolds number increases. The radial and axial velocity distributions of 6SBT are clearly superior to those of 6BT at agitation speed of 5 r/s, while the power consumption is about 93% of that in 6BT agitation.%基于混沌混合理论,提出了一种错位叶片的结构形式,用来消除层流流场的混合隔离区.利用CFD的方法,对六弯叶涡轮(6BT)和错位六弯叶涡轮(6SBT)2种搅拌器在黄原胶水溶液中的流场变化进行研究,分析比较了2种搅拌器的流场结构、速度分布以及功率消耗的不同.结果表明,模拟计算得到的功率值与实验测量值吻合较好,6SBT桨在层流区的临界雷诺数为20;错位叶片搅拌流场结构不对称,可消除流场隔离区,搅动范围变大;随Re增大,对层流流场的改善效果增强,全槽的平均剪切速率得以提高,并且具有节能功效.在转速N=5 r/s的条件下,6SBT桨的轴向和径向速度分布整体上明显好于6BT桨,而功耗约为6BT桨的93%.

  11. Experimentos de disolución de CaCO3 en foraminíferos bentónicos aglutinados del Paleoceno-Eoceno en Zumaya (Cuenca Vasco-Cantábrica, España

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    Arreguín-Rodríguez, G. J.

    2015-06-01

    Full Text Available The largest extinction of deep-sea benthic foraminifera in the Cenozoic occurred during the Paleocene-Eocene Thermal Maximum event (PETM, ~55.8 Ma. Much has been speculated about the causes of such extinction, and proposed mechanisms include changes in productivity and/or oxygenation of bottom waters, metabolic changes and in the composition of the food supply to the seafloor, or the ocean acidification related to the massive input of isotopically light carbon into the ocean-atmosphere system, among others. Here we analyse ocean acidification as a potential triggering mechanism of the extinctions. The early Eocene at the Zumaya section (Basque-Cantabrian Basin is marked by a 4 m-thick interval with a very low CaCO3 content. In order to analyse whether CaCO3 dissolution had a direct effect on the extinctions across the PETM, we car-ried out dissolution experiments on various species of agglutinated benthic foraminifera from Zumaya. In general, agglutinated species that do not disappear in the interval of most intense dissolution at Zumaya were not -or only slightly- affected by our dissolution experiments, since they do not have calcareous particles or cement. However, some species that went extinct or locally disappeared during the early Eocene, such as Dorothia cylindracea, Spiroplectammina spectabilis and Haplophragmoides cf. walteri, are resistant to dissolution. These results sug-gest that, in addition to ocean acidification, other factors must have contributed to the destabilization of benthic foraminiferal assemblages.Durante el evento de calentamiento global conocido como Máximo Térmico del Paleoceno-Eoceno (PETM por sus siglas en inglés; hace ~55.8 Ma tuvo lugar la mayor extinción de foraminíferos bentónicos de medios profundos de todo el Cenozoico. Mucho se ha especulado sobre las causas de dicha extinción, que incluyen cambios en la productividad y/o en la oxigenación de las aguas, cambios metabólicos y en la composición del

  12. The benthic macroinvertebrate fauna of highland streams in southern Brazil: composition, diversity and structure Fauna de macro-invertebrados bentônicos de rios de montanha no sul do Brasil: composição, diversidade e estrutura

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    Ludwig Buckup

    2007-06-01

    Full Text Available Benthic macroinvertebrate in four rivers, three in the Pelotas River basin (Divisa, Marco and Silveira rivers, in the headwaters of the Uruguai River and one in the Taquari-Antas system (Antas River, a tributary in the Guaíba basin, in the state of Rio Grande do Sul, were identified. Two samples were collected in summer, autumn and spring, with one replicate in each river. The total of 28,961 specimens included members of Platyhelminthes, Annelida, Acarina, Insecta, Crustacea and Mollusca. The Silveira and Marco rivers showed significant differences in the indices of Shannon-Weaver (H’, Simpson’s Reciprocal (1/D, Margalef (DMg and Equitability (E. The Silveira River showed the highest means of diversity and the EPT index (Ephemeroptera, Plecoptera, Trichoptera. Comparison among the diversity indices, considered individually, were insufficient to show differences in community structure, for the purpose of ecological characterization of the rivers. The EPT values characterized the Divisa River as having the highest abundance (73%, followed by the Marco (71%, Antas (48% and Silveira (36%. These results suggest that the Silveira River is subject to moderate environmental stress, from human impact, although it showed the highest diversity of the major macrobenthic groups.Os macro-invertebrados bentônicos que ocorrem em quatro rios, três pertencentes à bacia do Rio Pelotas (Rios Divisa, Marco e Silveira nas cabeceiras do Rio Uruguai e um ao sistema Taquari-Antas (Rio Antas, tributário da bacia do Guaíba, no Estado do Rio Grande do Sul, foram identificados. Duas amostras foram coletadas no verão, outono e primavera, com uma réplica em cada rio. Foram coletados 28961 espécimes de macro-invertebrados compreendendo Platyhelminthes, Annelida, Acarina, Insecta, Crustacea e Mollusca. Na comparação entre os rios, Silveira e Marco mostraram diferenças significativas nos índices de Shannon-Weaver (H’, no Recíproco de Simpson (1/D, de

  13. Effects of carbofuran and metsulfuron-methyl on the benthic macroinvertebrate community in flooded ricefields Efeito do carbofurano e metsulfuron-methyl sobre a comunidade de macroinvertebrados bentônicos de lavoura de arroz irrigado

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    Joele Baumart

    2011-06-01

    Full Text Available AIM: This study evaluated the effect of the insecticide carbofuran and the herbicide metsulfuron-methyl on the abundance and diversity of benthic macroinvertebrates in a paddy ricefield. METHODS: To achieve this goal, two pesticide treatments [the insecticide carbofuran (IC and the herbicide metsulfuron-methyl (HM] and a control (Co treatment with no added pesticide were established in an experimental area of the Plant Science Department of the Federal University of Santa Maria. Soil samples were collected in triplicate from each treatment 30 days before and 1, 10, and 51 days after the pesticide application, for macrofauna identification. RESULTS: Among the 21 taxa identified, Trichoceridae was present only in Co, Hydroptilidae was recorded only in IC, and Corixidae in HM. In Co, the most abundant group was Annelida, while in IC and HM Diptera (Chironomidae was dominant. Significant differences were observed between Co and IC, in the density of Odontoceridae (Control>IC and Hydrophilidae (ControlHM and Hirudinea (ControlOBJETIVO: O objetivo desse estudo foi avaliar o efeito do inseticida carbofurano e do herbicida metsulfuron-methyl na abundância e diversidade de macroinvertebrados bentônicos em campo de arroz irrigado. MÉTODOS: Para isto, dois tratamentos com agrotóxicos [o inseticida carbofurano (IC e o herbicida metsulfuron-methyl (HM] e um controle (Co, tratamento sem pesticida, foram aplicados em uma área experimental no Departamento de Fitotecnia da Universidade Federal de Santa Maria. Amostras de solo foram coletadas em triplicatas em cada tratamento 30 dias antes (DBA e 1, 10 e 51 dias após a aplicação dos pesticidas, posteriormente a macrofauna foi identificada. RESULTADOS: Vinte e um (21 taxa foram identificados, entre esses Trichoceridae esteve presente apenas em Co, enquanto que Hydroptilidae foi coletado apenas em IC, e Corixidae em HM. Em Co e IC, o grupo mais abundante foi Annelida, e em HM foi Diptera (Chironomidae que

  14. Development and characterisation of 20 microsatellite loci isolated from the large bent-wing bat, Miniopterus schreibersii (Chiroptera: Miniopteridae) and their cross-taxa utility in the family Miniopteridae.

    Science.gov (United States)

    Wood, Rebecca; Weyeneth, Nicole; Appleton, Belinda

    2011-07-01

    The large bent-wing bat, Miniopterus schreibersii (Kuhl 1819), has a long history of taxonomic uncertainty and many populations are known to be in a state of decline. Microsatellite loci were developed for the taxonomic and population genetic assessment of the Australian complex of this species. Of the 33 primer sets designed for this research, seven (21%) were deemed suitably polymorphic for population-level analyses of the Australian taxa, with five (71%) of these loci revealing moderate to high levels of polymorphism (PIC = 0.56 to 0.91). The cross-taxa utility of the M. schreibersii microsatellite markers was assessed in the microbat (Chiroptera) family Miniopteridae. Sub-species and species covering the Miniopteridae's global distribution (with the exception of the Middle East) were selected, numbering 25 taxa in total. Amplification was successful for 26 loci, of which 20 (77%) were polymorphic. High cross-taxa utility of markers was observed with amplification achieved for all taxa for between four (20%) and 20 (100%) loci, and polymorphism was considered moderate to high (PIC = 0.47-0.91) for 12 (60%) of these loci. The high cross-taxa utility of the microsatellites reported herein reveal versatile and cost-effective molecular markers, contributing an important genetic resource for the research and conservation of Miniopteridae species worldwide.

  15. A new species of bent-toed gecko, genus Cyrtodactylus Gray, 1827 (Reptilia: Squamata: Gekkonidae), from Jawa Timur Province, Java, Indonesia, with taxonomic remarks on C. fumosus (Müller, 1895).

    Science.gov (United States)

    Hartmann, Lukas; Mecke, Sven; Kieckbusch, Max; Mader, Felix; Kaiser, Hinrich

    2016-01-26

    A new species of the gekkonid lizard genus Cyrtodactylus Gray, 1827 is described from Klakah, Lumajang Regency, Jawa Timur Province, Java, Indonesia. Cyrtodactylus klakahensis sp. nov. can be distinguished from all other congeners by the presence of (1) a deep precloacal groove in males, (2) three rows of enlarged precloacofemoral scales, of which the third row bears 37-38 pores in males, (3) three or four rows of enlarged scales between the precloacofemoral scale rows and the cloaca, forming distinct chevrons, (4) raised and strongly keeled dorsal tubercles in 15-19 rows at midbody, (5) an indistinct lateral fold, (6) 17-20 subdigital lamellae under the 4th toe, and (7) subcaudal scales which are not transversely enlarged. Cyrtodactylus klakahensis sp. nov. is only the third bent-toed gecko species described from Java, indicating that the diversity of this genus on this island has been neglected in the past. Furthermore, we confirm that C. fumosus (Müller, 1895) is a species that possesses a precloacal groove in males and is most likely restricted to northern Sulawesi. That species is defined by a single female holotype (NMB-REPT 2662). Specimens in museum collections catalogued as C. fumosus from localities elsewhere are misidentified and likely represent undescribed species.

  16. Colonização de macroinvertebrados bentônicos em detritos foliares em um riacho de primeira ordem na Floresta Atlântica do nordeste brasileiro

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    Iris Gabrielly Arruda dos Santos

    2015-03-01

    Full Text Available O objetivo do estudo foi avaliar a colonização de macroinvertebrados bentônicos em detritos foliares de Inga ingoides (Leguminosae em experimentos de campo em um riacho de primeira ordem da Mata Atlântica do Estado de Pernambuco no nordeste do Brasil. Um total de 270 bolsas de folhiço, distribuídas em três trechos do riacho com características similares em relação à morfologia e parâmetros físicos e químicos da água foram submersas, entre fevereiro a julho de 2013 e retiradas após 7, 30, 60, 90 e 120 dias. Dois tratamentos foram utilizados: colonização e exclusão da macrofauna. O percentual de biomassa remanescente final (%R foi maior para bolsas de colonização do que para as de exclusão, evidenciando a efetiva participação dos macroinvertebrados no processo de decomposição. Os fragmentadores apresentaram menor participação no processo de decomposição foliar de I. ingoides, sendo Tripletides (Trichoptera: Leptoceridae, Polypedillum e Stenochironomus (Diptera, Chironomidae os táxons predominantes na macrofauna. Filtrador foi o grupo trófico funcional predominante (45,6%, seguido por predador (31,2%, coletor (11,8%, raspador (6,7% e fragmentador (4,8%.

  17. Foraminíferos bentónicos de tres playas en Isla Barú (Caribe colombiano y su relación con algunos parámetros sedimentológicos

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    Parada Ruffinatti Carmen

    1995-11-01

    Full Text Available Benthic foraminiferal communities and sediments in three shores of Barú island are studied. These ones were selected because they have different characteristics. In Mohan beach, situed al norwest side of the island, the sediments are coarse grained, with high contents of calcium carbonate. In Marimberos beach, situated at Barbacoas bay, the sediments are something finer and of continental origino at Muertos beach, situated at southeastearn extreme, there are intermediate characteristics. About the biothic component, there are different distribution between the foraminiferal species, that are related with calcium carbonate, grain size and e/N relationship.Se estudian las comunidades de foraminíferos bentónicos y sedimentos en tres playas de isla Barú, escogidas por tener características diferentes. En playa Mohán, ubicada al costado noroeste de la isla, predomina el sedimento grueso con alto contenido de carbonato de calcio; en playa Marimberos, situada en la bahía de Barbacoas, se evidencia el aporte continental a través del canal del Dique y los sedimentos son algo más finos; en playa Muertos, ubicada al extremo sureste, las características son intermedias. En cuanto al componente biótico, se observan diferencias en la distribución de especies de foraminíferos, relacionadas con los cambios de porcentaje de carbonato de calcio, tamaño de grano y relación Carbono/Nitrógeno.

  18. Gobernanza y capital social en el co-manejo de recursos bentónicos en Chile: aportes del análisis de redes al estudio de la pesca artesanal de pequeña escala.

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    Stefan Gelcich

    2012-09-01

    Full Text Available El co-manejo o manejo colaborativo es considerado una institución relacional ya que pone el énfasis, no sólo en la administración de los recursos propiamente tales, sino en las relaciones sociales que se establecen entre múltiples actores con diversos intereses en el territorio. Por esto, existe un creciente interés en su estudio desde el análisis de redes sociales (ARS y el concepto afín de capital social. En este artículo presentamos dos aplicaciones del uso de ARS para comprender el co-manejo, utilizando el sistema chileno de Áreas de Manejo y Explotación de Recursos Bentónicos (AMERB como caso de estudio. Específicamente se aplican herramientas del ARS para: (1 describir y analizar la red de gobernanza que subyace el régimen de AMERB, y (2 explorar el rol del capital social de las organizaciones de pescadores en el funcionamiento y desempeño del co-manejo. En base a las aplicaciones descritas en el artículo planteamos que el enfoque de redes sociales entrega una mirada promisoria y complementaria para el desarrollo y reformulación de políticas públicas más efectivas y con creciente participación de las comunidades locales.

  19. A new type of structure of four bent corners bending & piercing compound mold%一种新型的四角弯曲冲孔复合模结构

    Institute of Scientific and Technical Information of China (English)

    茆琦; 李潍

    2012-01-01

    结合支撑托架冲件的具体案例,阐述了一种新型的四角弯曲冲孔复合模结构.该结构通过采用浮动式的弯曲凸模,能够保证先后两次U形弯曲和冲孔依次进行,且冲孔时消除了弯曲变形的发生.该结构能够保证弯曲件上孔及孔间距的精度,具有一定的独创性.%Based on the specific case of support bracket stamping, in this paper, a new type of structure of four bent corners bending & piercing compound mold is stated. By using floating bending punch, this structure can guarantee that it has two U bending and piercing in turn and the bending deformation has been eliminated when piercing happens. This structure can also guarantee the hole spacing accuracy of bending parts, and has some originality.

  20. Casting technique optimization of the primary coolant bent pipes used for a pressurized water reactor nuclear power plant by ProCAST software%基于ProCAST软件优化压水堆核电站一回路弯管铸造工艺

    Institute of Scientific and Technical Information of China (English)

    吉晓霞; 王根启; 杨滨; 王西涛

    2012-01-01

    利用ProCAST软件对压水堆核电站一回路90°弯管的充型和凝固过程进行了模拟.结果表明,浇注过程中金属液充型平稳,浇注系统设计符合顺序凝固原则.利用固相率法预测了弯管易出现缩孔缩松的位置,优化设计后获得了无缩孔缩松的弯管铸造工艺.研究表明,运用ProCAST软件有利于提高弯管铸件的工艺出品率.%The filling and solidification processes of the primary coolant 90° bent pipes in pressurized water reactors(PWR) were simulated by ProCAST software.The simulation results show that molten steel can be filled smoothly,which demonstrates that the gating system plan meets the directional solidification principle.The locations of shrinkage and porosity in the bent pipes were predicted by using the solid fraction method.A series of technique optimizations were carried out in order to eliminate the shrinkage and porosity,so an optimized casting technique was finally obtained for the bend pipes.It is indicated that the casting yield of the bent pipes can be increased using ProCAST software analysis.

  1. Disjoint geographical distribution of intertidal and nearshore benthic invertebrates in the Southern Hemisphere Distribuciones geográficas disyuntas de invertebrados bentónicos intermareales y del submareal somero en el Hemisferio Sur

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    JUAN C CASTILLA

    2000-12-01

    Full Text Available Biogeographical explanations for the extant and paleo disjoint geographical distribution in the southern hemisphere of five species of nearshore marine benthic invertebrates: Gaimardia trapesina, Ostrea chilensis, Pyura stolonifera taxonomic complex, Aulacomya ater and Concholepas concholepas, showing distinctive reproductive strategies and early life history characteristics are reviewed and analyzed. Through the use of published and new information we contrasted the following hypotheses: a vicariance-historical process, b epiplanktonic larval dispersal, c juvenile/adult dispersal through rafting and d planned or accidental anthropogenic dispersal mechanisms. The juvenile/adult transoceanic dispersal hypothesis by rafting was the only one impossible to be rejected for the species analyzed. The implication and future direction for research in this area are discussedSe revisa y analiza las posibles explicaciones para la distribución geográfica disyunta, presente y pasada, en el hemisferio sur de cinco especies de invertebrados bentónicos marinos litorales: Gaimardia trapesina, Ostrea chilensis, el complejo taxonómico Pyura stolonifera, Aulacomya ater y Concholepas concholepas, con estrategias reproductivas y características de historia de vida distintas. Se discute y pone a prueba, usando información original o publicada, las siguientes hipótesis: a procesos históricos de vicarianza, b dispersión de larvas epi-planctónicas, c dispersión de juveniles o adultos por transporte pasivo y d dispersión antropogénica planificada o accidental. La hipótesis de dispersión transoceánica de juveniles o adultos fue la única imposible de rechazar para las especies analizadas. Se discute las direcciones futuras de investigación en esta área

  2. Efeito de metais Cobre (Cu e Zinco (Zn sobre a comunidade de macroinvertebrados bentônicos em riachos do sul do Brasil - DOI: 10.4025/actascibiolsci.v30i3.677 The effect of metals (Cu and Zn on the benthic macroinvertebrate community in streams in southern Brazil - DOI: 10.4025/actascibiolsci.v30i3.677

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    Luiz Ubiratan Hepp

    2008-10-01

    Full Text Available O objetivo deste estudo foi avaliar os efeitos de metais (Cu e Zn sobre a comunidade de macroinverterados bentônicos. Foram amostrados, trimestralmente, entre setembro de 2006 e junho de 2007, organismos e água em oito trechos de riachos de duas bacias hidrográficas influenciadas por urbanização e agricultura. Foram estimados os valores de densidade de organismos, riqueza taxonômica e diversidade de Shannon. Para avaliação dos dados, foram utilizados testes de variância e regressão linear simples. Os resultados demonstraram variabilidade das concentrações dos metais e da macrofauna entre as estações do ano e riachos estudados. O metal Cobre (Cu apresentou influência apenas sobre a densidade Chironomidae e o metal Zinco (Zn apresentou efeito sobre a densidade total da macrofauna bentônica e de Chironomidae. Nenhum dos metais apresentou efeitos sobre a riqueza e diversidade de macroinvertebrados. Os resultados indicam potencial bioindicador da comunidade bentônica na avaliação da qualidade integrada do ambiente.The aim of this study was to evaluate the effect of metals (Cu and Zn on the benthic macroinvertebrate community. The organisms and water were collected quarterly between September 2006 and June 2007, in eight sites in streams of two hydrographic basins, influenced by urbanization and agriculture. The values of organism density, taxonomic richness and the Shannon diversity index were calculated. For data evaluation, tests of variance and simple linear regression were used. The results showed variability in the metal concentration and benthic community among seasons and studied streams. Cu showed influence only on Chironomidae density. Zn demonstrated effect on the benthic community and Chironomidae density. None of the metals presented effect on the macroinvertebrate richness and diversity. The results indicate a bioindicator potential of the benthic community in the evaluation of integral quality of the environment.

  3. Quasi-static test of steel frame-bent structures of large thermal power plant main buildings%大型火电厂钢结构主厂房框排架结构拟静力试验研究

    Institute of Scientific and Technical Information of China (English)

    薛建阳; 梁炯丰; 彭修宁; 刘祖强; 茅荣华

    2012-01-01

    对1榀3跨5层的钢框排架主体结构进行了低周反复加载试验,观测了框排架的破坏形态,得到了试件的荷载-位移滞回曲线、骨架曲线,分析了钢框排架的破坏机制、滞回性能、延性、耗能能力、刚度退化等力学性能。结果表明:钢框排架结构的破坏机制为先梁端后柱端出现塑性铰的混合破坏机制,滞回曲线较饱满,整体位移延性系数大于4.0,等效黏滞阻尼系数达到0.189。钢框排架结构体系总体上表现出良好的抗震能力,适合高烈度抗震设防区采用。模型结构的层间位移角在底层和第二层较大,为薄弱层;煤斗梁地震反应较强,设计时要特别注意。%Through the experimental study on the model of a three-bay and five-story steel frame-bent structures under low cycle reversed loading,the failure condition of frame-bent structures was observed.The load-displacement,hysteretic loops and skeleton curve of tested model were obtained.The failure mechanism,hysteretic behavior,ductility,energy dissipation capacity and stiffness degradation were investigated.The results show that the failure mechanism of steel frame-bent structures is the first occurrence of beam-hinge and then column-hinge mechanism.The hysteretic loops are plump.The average of the overall ductility factors is greater than 4.The equivalent viscous damping coefficient is 0.189.The steel frame-bent structure exhibits excellent seismic behavior,and can be adopted in high seismic fortification zones.The inter-story drift is relatively large on the bottom story and the second story,namely the weak stories.And there are large seismic forces at the coal hopper beams,which must be paid attention in design.

  4. Impacto de "El Niño 1997-98" sobre el asentamiento larval de algunos invertebrados marinos bentónicos de bahía Independencia, Pisco -Perú

    Directory of Open Access Journals (Sweden)

    Elmer Ramos

    2014-06-01

    Full Text Available Se evaluó mensualmente los cambios y la magnitud del impacto de "El Niño" (EN, sobre el mecanismo del asentamiento larval de algunos invertebrados marinos bentónicos, en sustratos artificiales filamentosos (fibra nylon, entre enero 1996 y julio 1998, en una estación fija, a 10m de profundidad, situada en el lado oriental de la Isla Independencia, en Bahía Independencia, Durante 1996, en la fase fría "La Niña" (LN, el número de especies presentó un pico en abril y la densidad en junio. En la fase cálida EN 199798, la densidad total y el número de especies, presentaron un primer pico en marzo de 1997, luego, un segundo pico, en febrero y julio de 1998, respectivamente. Un primer grupo de especies que intensificó su asentamiento durante la fase fría LN 1996, estuvo constituido por el bivalvo Hiatella solida, el turbelario Notoplana sp. y el gastrópodo Caecum chilense. El segundo grupo intensificó su asentamiento en la etapa temprana de la fase cálida EN 1997-98, Y lo formaron el braquiópodo Discinisca lamel/osa, el equinodermo Ophíactís kr6yerí y bivalvos de la Familia Mytllidae, Un tercer grupo, mostró una intensificación del asentamiento larval, en la etapa tardía de la fase cálida EN 1997-98, a inicios de 1998, y fue formado por el bivalvo Argopecten purpuratus y un gastrópodo turriforme. La aparición de larvas recién asentadas de especies tropicales, como el bivalvo Ptería stema y el gastrópodo Epitoníum sp., tuvo lugar en la etapa tardía de la fase cálida EN 1997-98.

  5. Patrones de distribución espacial de ensambles de macroinvertebrados bentónicos de un sistema fluvial Andino Patagónico Spatial distribution patterns of benthic macroinvertebrates assemblages in an Andean Patagonian fluvial system

    Directory of Open Access Journals (Sweden)

    CAROLINA MOYA

    2009-01-01

    Full Text Available En enero de 2006 se estudiaron los patrones espaciales de distribución de comunidades de macroinvertebrados bentónicos de la cuenca hidrográfica del río Baker (45°50' O y 47°55' S y los principales factores controladores, intentando cubrir la mayor variedad de ecosistemas lóticos. Para llevar a cabo el estudio se seleccionaron 27 estaciones de muestreo ubicadas en las diferentes subcuencas del río. En cada estación se realizó una caracterización fisicoquímica del agua (conductividad, oxígeno disuelto, pH, temperatura y turbidez, y se documentaron las características del tramo de río (e.g. ancho del cauce y tipo de sedimento e información cartográfica utilizando un sistema de información geográfica (SIG. Se identificaron un total de 51 taxa que correspondieron en su mayoría a larvas de insectos (80 %. Los grupos con mayor riqueza fueron los órdenes Ephemeroptera (15 taxa, Plecoptera (8 taxa y Trichoptera (8 taxa. Los análisis de clasificación y ordenación realizados con los datos de abundancia, permitieron reconocer siete grupos de estaciones diferentes (A-F que fueron estadísticamente significativos (P In January of 2006 we studied the distributional patterns of benthic macroinvertebrate communities of the Baker river basin (45°50' O and 47°55' S and their main controlling factors trying to cover the greater variety of the lotic ecosystems. To carry out the study, 27 sampling stations were located in the different sub basins of the river. In each station, physical-chemical parameters of the column of water were quantified (conductivity, dissolved oxygen, pH, temperature and turbidity, and documented characteristics of the segment (e.g. wide of the channel and sediment type and cartographic information using a geographic information system (GIS and complemented with cartographic information using GIS. Identified a total of 51 taxa, are mostly insect larvae (80 %. The groups most richness were orders Ephemeroptera (15

  6. Impacto de la captura ilegal en pesquerías artesanales bentónicas bajo el régimen de co-manejo: el caso de Isla Mocha, Chile

    Directory of Open Access Journals (Sweden)

    Ricardo M Bandin

    2014-07-01

    Full Text Available El régimen de Áreas de Manejo y Explotación de Recursos Bentónicos (AMERB en Chile, considerado uno de los más grandes experimentos de co-manejo a escala global, enfrenta aún amenazas como el robo de recursos. En las AMERB dedicadas al recurso 'loco' (Concholepas concholepas la administración pesquera establece capturas totales permisibles suponiendo robos nulos, comprometiendo asi su sustentabilidad. Tomando como caso de estudio las AMERB dedicadas al recurso 'loco' en la Isla Mocha, mediante entrevistas a usuarios de AMERB, consultas a autoridades fiscalizadoras, y acopio de data secundaria, se reconstruyó una serie anual de robos, se simuló el impacto bio-económico del robo en una AMERB, y se sistematizó la opinión de los usuarios sobre las causas del robo y sus posibles soluciones. Los robos representan entre 32-68% de los ingresos brutos anuales históricos de las AMERB. Según las proyecciones bio-económicas, un stock de 'loco' en AMERB seria resiliente a toda combinación de niveles propuestos de 'Robo', 'Reglas de Cosecha' y 'Precios de Loco', excepto ante un 'Robo Descontrolado' (i.e., doble de la tasa de mortalidad por robo máxima histórica que agota la pesquería formal. Los usuarios de AMERB consideran más grave al robo realizado por pescadores no-isleños respecto del robo isleño, identificando incentivos comunes a ambos; esperan mayor acción del Estado sobre los infractores no-isleños, y confían más en sus propias organizaciones para controlar a los infractores isleños. Para combatir los robos en AMERB se propone mitigar sus incentivos socio-económicos, asignar en algunos casos derechos exclusivos de acceso territorial a las organizaciones asignatarias, y definir estrategias contra las operaciones ilegales previa conciliación de objetivos entre autoridades y grupos de interés.

  7. Identificación de macro invertebrados bentónicos en los ríos: Pindo Mirador, Alpayacu y Pindo Grande; determinación de su calidad de agua

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    Alexandra Endara

    2012-12-01

    Full Text Available En un estudio realizado en el mes de mayo del 2012, utilizando una red Surber de 30 x 30 cmde área de superficie y 0,5 mm de abertura de malla, en los ríos: Pindo Mirador, Pindo Grandey Alpayacu, ubicados en el sector de Mera, provincia de Pastaza de la Amazonía ecuatoriana,se analizó la diversidad y la abundancia de los macro invertebrados bentónicos utilizando losíndices BMWP/Col y EPT. Se logró determinar que la calidad del agua de los ríos PindoMirador y Pindo Grande es buena mientras la del río Alpayacu es mala. Este estudio da unaidea general de la situación ambiental de los ecosistemas lóticos cercanos a la EstaciónBiológica Pindo Mirador. Los resultados de ésta investigación permiten determinar laimportancia de las micro-cuencas de los ríos Pindo Mirador y Pindo Grande como fuente deagua para las poblaciones que se encuentran río abajo, así como el modo en el cual lapresencia o ausencia de organismos bioindicadores (macroinvertebrados indica la calidad delagua y de los bosques de la micro-cuenca.Abstract:In May 2012, using a 30x30 cm surface and 0.5 mm aperture Surber net in the rivers: PindoMirador, Pindo Grande and Alpayacu, located in Mera, Pastaza, Ecuadorian Amazonia, thediversity and abundance of macro invertebrates was analyzed applying the BMWP/Col and theEPT indexes. It was determined the good Pindo Mirador, Pindo Grande and Alpayacu rivers’water quality, as well as the bad Alpayacu river’s water quality. This work provides an overviewof the environmental situation of aquatic ecosystems near Pindo Mirador Biological Station, ithighlights the importance of the rivers’ micro-watersheds near Pindo Mirador Biological Station,used as water source by the populations living downstream, and shows how macroinvertebrates can be used as bioindicators for the water and forests quality.

  8. Radiation Reaction in a Bent Focusing System

    Science.gov (United States)

    Huang, Zhirong; Chen, Pisin; Ruth, Ronald D.

    1996-05-01

    We have shown that in a straight, continuous focusing channel the radiation reaction is different from that in a bending magnet. Quantum excitation to the transverse action is absent in this focusing system, and the radiation damping is faster in the transverse direction than in the longitudinal one. In this talk we study the effect of radiation in a combined-function system, where both focusing and bending fields are present. In one case where the bending dominates over the focusing, we recover the result of standard synchrotron radiation damping in storage rings. In the other case where the focusing dominates over the bending, we find that the lack of quantum excitation and the asymmetric damping found in a straight focusing channel still hold. In addition, the possibility of designing a focusing-dominated damping ring to demonstrate and apply this effect is discussed.

  9. Post Impressions: Music Writing as Bent Travelogue

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    Hollis Taylor

    2011-08-01

    Full Text Available The wind is our universal musician and has been recognized as such for millennia. If the wind can play a fence as an aeolian harp, then a violinist armed with a bow could also cause these gigantic structures to sing. Thus, an American woman and an Australian man set out to explore and perform on the giant musical instruments covering the continent of Australia: fences. This presentation excerpts highlights from the voyage, illuminating the range of sounds to be drawn out of a five-wire fence. Playing fences reveals a sound world that is embedded in the physical reality and the psyche of the culture. In pursuit of their instruments, including the Rabbit-Proof Fence and the 5300-kilometre–long Dingo Fence, the duo travels 40,000 kilometres, engaging with a singing dingo, an auctioneer, an Aboriginal gumleaf virtuoso, bush musicians, the first (now ruined piano in Central Australia, and the School of the Air’s distorted, modulating, phasing white and pink electronic noise. PLEASE NOTE: there are four supplementary files that accompany this contribution. Click on the tab 'Supplementary Files' on the right hand side of the screen when accessing the pdf of the article.

  10. Channeling and radiation in periodically bent crystals

    CERN Document Server

    Korol, Andrey V; Greiner, Walter

    2012-01-01

    The development of coherent radiation sources for sub-angstrom wavelengths - i.e. in the hard X-ray and gamma-ray range - is a challenging goal of modern physics. The availability of such sources will have many applications in basic science, technology and medicine, and, in particular, they may have a revolutionary impact on nuclear and solid state physics, as well as on the life sciences. The present state-of-the-art lasers are capable of emitting electromagnetic radiation from the infrared to the ultraviolet, while free electron lasers (X-FELs) are now entering the soft X-ray region. Moving

  11. High Throughput Bent-Pipe Processor Demonstrator

    Science.gov (United States)

    Tabacco, P.; Vernucci, A.; Russo, L.; Cangini, P.; Botticchio, T.; Angeletti, P.

    2008-08-01

    The work associated to this article is a study initiative sponsored by ESA/ESTEC that responds to the crucial need of developing new Satellite payload aimed at making rapid progresses in handling large amounts of data at a competitive price with respect to terrestrial one in the telecommunication field. Considering the quite limited band allowed to space communications at Ka band, reusing the same band in a large number of beams is mandatory: therefore beam-forming is the right technological answer. Technological progresses - mainly in the digital domain - also help greatly in increasing the satellite capacity. Next Satellite payload target are set in throughput range of 50Gbps. Despite the fact that the implementation of a wideband transparent processor for a high capacity communication payload is a very challenging task, Space Engineering team in the frame of this ESA study proposed an intermediate step of development for a scalable unit able to demonstrate both the capacity and flexibility objectives for different type of Wideband Beamforming antennas designs. To this aim the article describes the features of Wideband HW (analog and digital) platform purposely developed by Space Engineering in the frame of this ESA/ESTEC contract ("WDBFN" contract) with some preliminary system test results. The same platform and part of the associated SW will be used in the development and demonstration of the real payload digital front end Mux and Demux algorithms as well as the Beam Forming and on Board channel switching in frequency domain. At the time of this article writing, despite new FPGA and new ADC and DAC converters have become available as choices for wideband system implementation, the two HW platforms developed by Space Engineering, namely WDBFN ADC and DAC Boards, represent still the most performing units in terms of analog bandwidth, processing capability (in terms of FPGA module density), SERDES (SERiliazer DESerializers) external links density, integration form factor (6U C-PCI) and modularity (they are both rack mounted boards).

  12. Sequences, Bent Functions and Jacobsthal sums

    CERN Document Server

    Helleseth, Tor

    2010-01-01

    The $p$-ary function $f(x)$ mapping $\\mathrm{GF}(p^{4k})$ to $\\mathrm{GF}(p)$ and given by $f(x)={\\rm Tr}_{4k}\\big(ax^d+bx^2\\big)$ with $a,b\\in\\mathrm{GF}(p^{4k})$ and $d=p^{3k}+p^{2k}-p^k+1$ is studied with the respect to its exponential sum. In the case when either $a^{p^k(p^k+1)}\

  13. Space-time as strongly bent plate

    CERN Document Server

    Kokarev, S S

    1999-01-01

    Futher development is made of a consept of space-time as multidimensional elastic plate, proposed earlier in [20,21]. General equilibrium equations, including 4-dimensional tangent stress tensor - energy-momentum tensor of matter - are derived. Comparative analysis of multidimensional elasticity theory (MET) and GR is given. Variational principle, boundary conditions, energy-momentum tensor, matter and space-time signature are reviewed within the context of MET.

  14. Riparian leaf litter processing by benthic macroinvertebrates in a woodland stream of central Chile Procesamiento de detritus ripariano por macroinvertebrados bentónicos en un estero boscoso de Chile central

    Directory of Open Access Journals (Sweden)

    CLAUDIO VALDOVINOS

    2001-06-01

    un importante impacto sobre las características energéticas de las comunidades fluviales de Chile central. Actualmente, los bosques exóticos existentes en esta área están compuestos principalmente por Pinus radiata (D. Don (pino insigne, llegando a cerca. del 80 % de las más de 1.800.000 ha de plantaciones forestales. El objetivo de este estudio fue analizar el efecto de camadas de hojas de una especie nativa dominante (Nothofagus pumilio y una especie exótica (P. radiata sobre el procesamiento de detritus realizado por macroinvertebrados bentónicos, en una cuenca experimental de Chile central (estero Rucúe; 36° 20' 00" S, 71° 47'40" O. Los resultados muestran que las tasas de procesamiento de los paquetes de hojas de la especie nativa son superiores a la exótica, sugiriendo que la sustitución de la flora nativa caducifolia por coníferas exóticas tiene un importante impacto sobre los componentes energéticos de los ecosistemas fluviales de Chile central. Los coeficientes de pérdida (k fueron 0,0072 para N. pumilio y 0,0027 para P. radiata. La abundancia y biomasa de fragmentadores por gramo de paquete de hojas explican las diferencias en las tasas de procesamiento de hojas, especialmente dos plecópteros Gripopterygidae, Limnoperla jaffueli y Antarctoperla michaelseni

  15. Choosing the best non-parametric richness estimator for benthic macroinvertebrates databases Eligiendo el mejor estimador no paramétrico para calcular riqueza en bases de datos de macroinvertebrados bentónicos

    Directory of Open Access Journals (Sweden)

    Carola V. Basualdo

    2011-06-01

    Full Text Available Non-parametric estimators allow to compare the estimates of richness among data sets from heterogeneous sources. However, since the estimator performance depends on the species-abundance distribution of the sample, preference for one or another is a difficult issue. The present study recovers and revalues some criteria already present in the literature in order to choose the most suitable estimator for streams macroinvertebrates, and provides some tools to apply them. Two abundance and four incidence estimators were applied to a regional database at family and genus level. They were evaluated under four criteria: sub-sample size required to estimate the observed richness; constancy of the sub-sample size; lack of erratic behavior and similarity in curve shape through different data sets. Among incidence estimators, Jack1 had the best performance. Between abundance estimators, ACE was the best when the observed richness was small and Chao1 when the observed richness was high. The uniformity of curves shapes allowed to describe the general sequences of curves behavior that could act as references to compare estimations of small databases and to infer the possible behavior of the curve (i.e the expected richness if the sample were larger. These results can be very useful for environmental management, and update the state of knowledge of regional macroinvertebrates.Los estimadores no paramétricos permiten comparar la riqueza estimada de conjuntos de datos de origen diverso. Empero, como su comportamiento depende de la distribución de abundancia del conjunto de datos, la preferencia por alguno representa una decisión difícil. Este trabajo rescata algunos criterios presentes en la literatura para elegir el estimador más adecuado para macroinvertebrados bentónicos de ríos y ofrece algunas herramientas para su aplicación. Cuatro estimadores de incidencia y dos de abundancia se aplicaron a un inventario regional a nivel de familia y género. Para

  16. Impacto dos efluentes de cultivo semi-intensivo de camarão sobre a fauna bentônica no sul do Brasil = Environmental impact of semi-intensive shrimp farming on benthic fauna in southern Brazil

    Directory of Open Access Journals (Sweden)

    Ana Carolina Canary

    2009-10-01

    Full Text Available O aumento dos cultivos em ambientes costeiros tem gerado preocupação arespeito do lançamento dos seus efluentes no ambiente aquático. Este estudo objetivou determinar o impacto dos efluentes de cultivos de camarões sobre a comunidade de macroinvertebrados bentônicos no estuário da lagoa dos Patos-Brasil. Este trabalho foi realizado numa fazenda de cultivo de camarão Litopenaeus vannamei. Como parâmetros dequalidade de água, foram monitorados quinzenalmente pH, oxigênio dissolvido, consumo de oxigênio e sólidos suspensos totais, sendo os locais de amostragem uma região-controle, saída do canal de drenagem da fazenda e bacia de sedimentação. As coletas de sedimento para a análise macrobentônica foram realizadas na saída da fazenda e no controle, e realizouse amostragem antes do início e quinzenalmente durante o cultivo. Os resultados mostram que a bacia de sedimentação neste cultivo é relativamente eficiente. Houve reduções no pH e na concentração de oxigênio e aumento no consumo de oxigênio na saída do canal de drenagem da fazenda. Além disso, foi observada alteração na estrutura da macrofauna no ambiente adjacente ao cultivo. Ocorreu redução das espécies mais sensíveis a distúrbios Nephtys fluviatilis e Heleobia australis e flutuações na abundância de Kalliapseudes schubartii.The increase in aquaculture activity in costal areas has raisedconcerns about the discharge of effluents in the aquatic environment. The aim of this study was to determine the impact of effluents from the cultivation in Patos Lagoon – Brazil, using benthic macroinvertebrates as indicators. This research was conducted in a farm of Litopenaeus vannamei shrimp. Water parameters such as pH, diluted oxygen, oxygen consumption and total suspended solids were checked every 15 days. The sampling sites were a controlled region, the farm outflow channel and the settling ponds. The sediment for analysis of the benthic was sampled in the farm

  17. 流体流变性对错位六弯叶桨流场特性的影响%Influence of fluid rheology on flow field features stirred by impeller of perturbed six-bent-bladed turbine

    Institute of Scientific and Technical Information of China (English)

    栾德玉; 周慎杰; 陈颂英

    2012-01-01

    利用计算流体力学(CFD)的方法,以高黏牛顿流体和假塑性非牛顿流体为研究对象,对错位六弯叶桨在层流域的搅拌流场特性进行了研究.结果表明:数值计算得到的功率值与实验测量值吻合较好,搅拌雷诺数对假塑性流体搅拌流场的量纲一速度和切应变速率影响较大,因此提高转速对改变流场的速度及切应变速率分布是一个有效的办法;而流体的流变性只对假塑性流体的量纲一速度有明显影响,对切应变速率影响较小,当流变指数n<0.3时与n基本无关.当流动由层流向过渡流转变时,搅拌桨的流量准数及泵送效率有显著提高;假塑性流体的流变指数降低时,其泵送效率显著下降.研究进一步认识了错位桨在不同流体中的搅拌流场特点,为高黏假塑性流体搅拌桨的设计、应用以及开发新型搅拌桨提供了参考.%The laminar flow field stirred by impeller of perturbed six-bent-bladed turbine (6PBT) in a cylindrical vessel was studied by means of computational fluid dynamics (CFD), with highly viscous Newtonian fluid and pseudoplastic non-Newtonian fluid as research object. Hie results show that the numerical calculated value of power consumption in glycerine is in good agreements with that of the experimental measurement. For pseudoplastic Quids, the value of Reynolds number has a major influence on the normalized velocity and shear rate, and the proper increasing speed would be a better way for improving the distribution of velocity field and shear rate. The rheological properties of fluids have obvious influences on the normalized velocity, but minor influences on shear rate specially; there is no correlation between the rheological index and shear rate when n <0. 3. With the flow development from the laminar flow to the transitional flow regime, the flow number and pumping efficiency of 6PBT impeller increase considerably. Moreover, the pumping efficiency of the impeller

  18. Macroinvertebrados bentónicos como indicadores de calidad de agua de ríos del sur de Chile Benthic macroinvertebrates as indicators of water quality of southern Chile rivers

    Directory of Open Access Journals (Sweden)

    RICARDO FIGUEROA

    2003-06-01

    Full Text Available La Cuenca Hidrográfica del Río Damas (40°39' S, 72°23' O, presenta una intensa actividad agrícola y ganadera en un 78,2 % de su superficie, lo cual se ha traducido en importantes aportes de nutrientes al ecosistema acuático. Los objetivos de este estudio fueron: (a analizar la distribución espacial de la macrofauna bentónica en la cuenca y (b determinar la viabilidad de utilizar el Índice Biótico de Familias (IBF para evaluación de la calidad de las aguas. Los muestreos se realizaron en enero de 1998 con una red Surber (0,09 m², en 15 sitios distribuidos en el curso principal y sus tributarios. Se registró un total de 77 taxa, siendo los grupos más diversos Plecoptera (16 %, Trichoptera (16 %, Diptera (14 % y Ephemeroptera (12 %. Se observó una marcada tendencia a la disminución de riqueza específica desde la cabecera de la cuenca hacia aguas abajo. Las abundancias, biomasas y el IBF, presentaron una tendencia inversa a la riqueza específica. IBF se correlacionó significativa y positivamente con el fósforo total (r² = 0,71, temperatura (r² = 0,66, nitrito (r² = 0,56, conductividad eléctrica (r² = 0,50, demanda biológica de oxígeno (r² = 0,46 y nitrógeno total (r² = 0,46, y negativamente con oxígeno disuelto (r² = 0,53, variables estrechamente asociadas al uso intensivo de fertilizantes en la cuenca. Los resultados sugieren que el IBF es un buen indicador de la calidad de las aguas de los ríos de cuencas agrícolas y ganaderas del sur de ChileThe Damas River Hydrographic Basin (40°39'S, 72°23' W presents an intense agricultural and cattle ranching activities in 78.2 % of its surface, which has resulted in important inputs of nutrients into the aquatic ecosystem. The objectives of this study were: (a to analyze the spatial distribution of the benthic macrofauna in the Damas basin, and (b to determine the feasibility of using the Families Biotic Index (FBI for the evaluation of water quality. The samplings were

  19. Caracterización del metabolismo y de la ofrerta de recursos de materia orgánica para los macroinvertebrados bentónicos en una quebrada de montaña de primer orden

    Directory of Open Access Journals (Sweden)

    Ospina Rodulfo

    2006-12-01

    Full Text Available Se realizaron medidas de la actividad metabólica de los substratos del bentos en la quebrada La Vieja, Bogotá,
    Colombia. Los datos de metabolismo se extrapolaron a un tramo, con el fin de confrontar estos resultados, con los supuestos del concepto del continuo del río (CCR para cabeceras. Se obtuvo un factor de corrección para hallar una equivalencia entre el área muestreada y el área real disponible para la actividad microbiana. A una escala de substrato, el epiliton y el musgo mostraron una relación P/R >1, mientras que a la escala de tramo, la relación P/R fue <1 cumpliendo el supuesto del CCR, para las cabeceras de los ríos. Se analizó el efecto de la velocidad de corte sobre la actividad metabólica de cinco substratos. Los resultados sugieren que existe una disminución de la productividad y la relación P/R, provocada al parecer por el efecto abrasivo de la velocidad de corte sobre las biopelículas de los substratos. La respiración no mostró cambios cuando la velocidad de corte fue incrementada. Se estimó la acumulación de las fracciones de Materia Orgánica Gruesa y Materia Orgánica Fina. La oferta de ambas fracciones de materia orgánica fue comparada con los Grupos Funcionales de macroinvertebrados bentónicos. Los resultados mostraron que la hojarasca no tiene una
    cobertura extensa y que normalmente es movilizada y compactada, ocupando un área menor o igual que la
    de otros substratos. Se analizó la relación entre los Grupos Funcionales de macroinvertebrados y la oferta de materia orgánica. Se presenta una tipología para los segmentos de ríos en Cundinamarca, Colombia. La tipología esta basada en dos descriptores adimensionales que estiman la estabilidad estructural y la actividad metabólica, en cada segmento de río obtenido por la intersección de las capas temáticas. La ponderación de cada capa fue obtenida a partir del valor absoluto porcentual de los coeficientes del primer componente en un

  20. Zoogeografía de macroinvertebrados bentónicos de la costa de Chile: contribución para la conservación marina Zoogeography of benthic macroinvertebrates of the Chilean coast: contribution for marine conservation

    Directory of Open Access Journals (Sweden)

    DOMINGO A. LANCELLOTTI

    2000-03-01

    Full Text Available La diversidad de macroinvertebrados marinos ha recibido una atención creciente, no obstante, con un escaso tratamiento en el contexto biogeográfico. Este estudio analiza los registros de 1.601 especies de macroinvertebrados bentónicos pertenecientes a: Demospongiae, Anthozoa, Polychaeta, Mollusca, Crustacea, Echinodermata y Ascideacea, agrupados en 10 zonas y tratados desde una perspectiva zoogeográfica. Mollusca (611 especies, Polychaeta (403 y Crustacea (370 corresponden a los grupos mejor representados a lo largo de la costa chilena, determinantes en el patrón global de la biodiversidad. Este aumenta suavemente de norte a sur, interrumpido por máximos que sugieren esfuerzos diferenciales de estudio más que un comportamiento natural de la biodiversidad. El grado de agrupamiento entre las zonas muestra las tres unidades biogeográficas definidas recientemente por Lancellotti & Vásquez. Este arreglo, que representa lo exhibido por los grupos más diversos, se ve alterado en los grupos menos representados donde las diferencias obedecen al patrón de afinidades mostradas por las zonas comprendidas dentro de la Región Templada Transicional. El quiebre zoogeográfico alrededor de los 41º S, sugerido largamente en la literatura, sólo ocurre en Echinodermata y Demospongiae, evidenciando en los otros taxa la existencia de un área de transición entre los 35º y 48º S, caracterizada por un reemplazo gradual de especies. Dentro de las regiones la biodiversidad muestra homogeneidad, contrario al endemismo, el que alcanza un máximo de 52% en la Región Templada Fría y que parece ser consecuencia del alto número de especies con registros únicos (38,2% de especies citadas para una sóla zona. Esto sugiere un desconocimiento de los macroinvertebrados chilenos (distribución y diversidad, sobrestimando el endemismo regional y distorsionando los patrones locales de biodiversidadThe diversity of marine macroinvertebrates has received increasing

  1. Controlling factors of benthic macroinvertebrates distribution in a small tropical pond, lateral to the Paranapanema River (São Paulo, Brazil Macroinvertebrados bentônicos e fatores controladores de sua distribuição em uma pequena lagoa tropical adjacente ao rio Paranapanema (São Paulo, Brasil

    Directory of Open Access Journals (Sweden)

    Erika Mayumi Shimabukuro

    2011-06-01

    Full Text Available AIM: The aim of the present study was to examine the benthic fauna in a marginal pond lateral to the Paranapanema River and to identify the main controlling factors of its distribution. Considering the small size of the lacustrine ecosystem, we expected that seasonal variations of the benthic community attributes are more important than spatial variations; METHODS: Two samplings, one in March and another in August, were carried out at nine sites in the pond. Sediment samples were obtained through a Van Veen grab for invertebrate sorting, granulometric analysis, and for quantification of organic matter in sediment. Other abiotic factors were measured, such as water transparency, dissolved oxygen, pH, electric conductivity, temperature, and depth of sediment sampling sites. Regarding the comparative analysis at spatial scale, no significant variations in density of the benthic invertebrate community were found. RESULTS: In relation to the studied abiotic factors, only depth presented significant differences among sampling sites; All the measured environmental parameters presented significant differences among sampling months, except depth and the physical and chemical characteristics of the sediment. The abundance of Chaoboridae and Chironomidae was the unique attribute with a significant difference in comparing the two months. A higher abundance of taxa occurred in August, especially for Oligochaeta, Nematoda, Chaoboridae, and Chironomidae; CONCLUSIONS: Because of the low structural complexity of the studied pond, we concluded that the changes in benthic macroinvertebrate community attributes were mainly due to seasonal effects.OBJETIVO: O presente estudo tem por objetivo examinar a fauna bentônica em lagoa marginal ao rio Paranapanema e os principais fatores reguladores da sua distribuição. Devido ao pequeno tamanho do ambiente lacustre, procurou-se mostrar que as variações sazonais dos atributos da comunidade bentônica são mais

  2. Caracterización preliminar de los invertebrados bentónicos capturados accidentalmente en la pesca de camarones en el norte del estado de Río de Janeiro, sudeste de Brasil Preliminary characterization of benthic invertebrates caught as by-catch in the shrimp fishery in the north of the Rio de Janeiro State, southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Igor David da Costa

    2009-01-01

    Full Text Available Para caracterizar la biodiversidad de invertebrados bentónicos que componen la fauna asociada a la pesca de camarones en el puerto del Farol de Sao Thomé, costa norte del estado de Río de Janeiro, se realizaron 11 pescas mensuales en el año 2004 con redes de arrastre de fondo, cuya área de operaciones comprende 3-5 mn desde la línea de costa, entre 22°00'S y 22°20'S. Los datos registrados de cada taxon y/o especie se refieren a la frecuencia de ocurrencia, frecuencia numérica, biomasa, índice de Importancia Relativa y abundancia. En total se registraron 27 especies de invertebrados bentónicos de Porifera, Cnidaria, Mollusca, Annelida, Crustácea, Echinodermata y Bryozoa. Crustácea fue el más representativo, tanto en número de ejemplares de Petrochirus diogenes, Hepatus pudibundus y Callinectes ornatos, como en biomasa de P. diogenes y H. pudibundas. En términos de frecuencia de ocurrencia en los muéstreos, 11 especies (40,7% fueron constantes; 6 (22,2% accesorias y 10 (37,0% accidentales.In order to characterize the biodiversity of the benthic invertebrate by-catch associated with the shrimp fishery at Farol de Sao Thome harbor, northern Rio de Janeiro State, Brazil, in 2004, 11 monthly trawls were conducted using bottom trawl nets between 22°00'S and 22°20'S and from 3 to 5 nm from the shoreline. The analyzed data for each talon and/or species include frequency of occurrence, numeric frequency, biomass, index of Relative Importance, and abundance. In total, 27 benthic invertebrate species were recorded, including Peripheral, Cnidarians, Mollusk, Annelid, Crustacea, Echinodermata, and Bryozoa. The most representative group was Crustacea, both in number of specimens (Petrochirus diogenes, Hepatus pudibundus, Callinectes ornatus and in biomass (P. diogenes, H. pudibundus. In terms of the frequency of occurrence in the samples, 11 species (40.7% were constant, 6 species (22.2% were accessories, and 10 species (37.0% were by-catch.

  3. Size structure of a heavily fished benthic/demersal community by shrimp trawling in the Colombian Caribbean Sea Estructura de tamaños de una comunidad bentónica/demersal fuertemente impactada por la pesca de arrastre camaronero en el Mar Caribe de Colombia

    Directory of Open Access Journals (Sweden)

    Paúl Gómez-Canchong

    2011-01-01

    Full Text Available The benthic and demersal communities in the Colombian Caribbean Sea (CCS are heavily fished by the shrimp trawling fishery, which presents very high discard levels. Here, we conducted an analysis of the size structure of these benthic and demersal communities in the northern and southern zones of the CCS. Sampling was conducted onboard shrimp trawlers throughout an entire year. No significant differences were found in the size distributions of the two zones, among sites within southern ecoregions, or among the analyzed cruises. This homogeneity in size structure is remarkable since the zones analyzed possess very different species compositions and environmental conditions. The observed size structures were adequately described by non-linear distributions rather than the traditionally employed linear normalized biomass size spectra. It is hypothesized that the non-linearity is due to the effect of fishing and particularly, of discarding. This study emphasizes the need for a greater understanding of the impacts that trawl fishing has on community size structure and the applicability of this knowledge towards fishery resource management in ecosystems with high diversity.Las comunidades bentónico-demersales en el Mar Caribe de Colombia (MCC son fuertemente explotadas por la pesca de arrastre camaronero, presentando niveles de descarte muy altos. Se efectuó un análisis de la estructura de tamaños de estas comunidades bentónico-demersales en las zonas norte y sur del MCC. Se realizaron muéstreos a bordo de las embarcaciones de arrastre de camarón a lo largo de un año. No se encontraron diferencias significativas entre las distribuciones de tamaños de las diferentes zonas, ecorregiones de la zona sur y cruceros analizados. Esta homogeneidad en la estructura de tamaños es destacable ya que las areas analizadas difieren en composición de especies y condiciones medioambientales. Las estructuras de tamaño observadas, fueron descritas

  4. Influence of environmental factors on benthic macroinvertebrate communities of urban streams in Vereda habitats, Central Brazil Influência de variáveis ambientais na comunidade de macroinvertebrados bentônicos de córregos urbanos de Veredas, Brasil Central

    Directory of Open Access Journals (Sweden)

    Renata de Moura Guimaraes Souto

    2011-09-01

    integridade do habitat nas comunidades de macroinvertebrados bentônicos têm aumentado nos anos recentes, entretanto, não há estudos avaliando a influência da urbanização nas comunidades de macroinvertebrados em córregos de veredas. Assim, ampliar o conhecimento da relação entre as variáveis abióticas e fauna bentônica é muito importante para a compreensão do funcionamento dos processos ecológicos e da integridade dos ecossistemas aquáticos. Este estudo investigou a influência de variáveis físicas e químicas nas comunidades de macroinvertebrados bentônicos ao longo de um gradiente de distúrbios antrópicos em quatro córregos de Vereda em Uberlândia (MG; um em uma área preservada e três na área urbana MÉTODOS: as amostras foram coletadas nas estações seca e chuvosa RESULTADOS: A análise de componentes principais separou o córrego da área preservada daqueles da área urbana por apresentar menores valores de DBO, DQO, tamanho do sedimento, condutividade, detergentes, pH, sólidos depositáveis e sólidos totais dissolvidos. Grupos sensíveis à poluição (e.g., Ephemeroptera e Trichoptera foram associados ao córrego da área preservada e grupos mais tolerantes (Chironomidae e Oligochaeta tiveram maior abundância nos córregos da área urbana. A Análise de Correspondência Canônica indicou que oxigênio dissolvido, condutividade, DBO, óleos e graxas e turbidez explicaram 56% da variação na distribuição e abundância de macroinvertebrados; CONCLUSÕES: comunidades bentônicas de córregos de Vereda em áreas urbanas no Bioma Cerrado parecem ser altamente afetadas pelas atividades humanas que aumentam a poluição orgânica da água e a sedimentação.

  5. 计算机辅助快速成型钛网在眼眶爆裂骨折整复中的应用%Orbital blowout fracture reconstruction using titanium mesh pre-bent with computer-aided rapid prototy-ping technology

    Institute of Scientific and Technical Information of China (English)

    张翔; 陈伟; 曹罡; 董震; 徐金科; 刘秉尧; 罗婷苑; 马娟; 张森林

    2016-01-01

    Objective This study was to evaluate the clinical outcomes of orbital blowout fracture repair using the individual titanium mesh bent by computer-aided rapid prototyping . Methods The CT imaging data of 11 cases of orbital blowout fracture were analyzed.The subciliary approach was used for the exposure of the fractures .An appropriate 3D-printed titanium mesh pre-bent by computer-aided rapid prototyping was selected and implanted according to the characteristics of a given defect .The surgical results were analyzed by evaluating diplopia , eyeball movement , enophthalmos , and the position of the titanium mesh and comparing the orbital vol-ume before and after surgery . Results All the operations were successfully accomplished .No remolding or trimming was needed for the pre-bent titanium mesh and implanted titanium mesh was tightly fixed to the orbital wall .The patients were followed up for 3 -12 months, which revealed no symptoms of diplopia in any of the patients . Volumetric analysis showed a significantly reduced orbital volume difference from (2.60 ±0.43) mL preoperatively to (-0.07 ±0.62) mL postoperatively (P<0.01).Enophthalmos was desirably correc-ted, with the enophthalmos difference decreased from (2.35 ±0.81)mm preoperatively to (-0.10 ±0.52) mm postoperatively (P<0.01).No extra-ocular muscle limitation was observed . Conclusion The individual titanium mesh bent with computer-aided rapid prototyping technology can be applied to orbital blowout fracture repair , which may achieve a high success rate of anatomic restoration of the orbital volume and effective prevention of enophthalmos .%目的:由于眶下壁和眶内侧壁的形态不规则,且衬垫的钛网通常是在术中由医师根据经验手工弯制和塑形,难以精确恢复眶壁的原有形态,故整复效果难以得到保障。本研究分析应用计算机辅助快速成型技术预弯的钛网修复眼眶爆裂骨折的临床疗效。方法根据11例眼眶爆裂骨折患

  6. Living (stained calcareous benthic foraminifera from recent sediments off Concepción, central-southern Chile (~36° S Foraminíferos bentónicos calcáreos vivos (teñidos en sedimentos recientes de Concepción, Chile centro-sur (~36° S

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    RAÚL TAPIA

    2008-09-01

    Full Text Available This study examines onshore-offshore and vertical distribution of living (Rose Bengal stained benthic foraminifera (> 180 μm fraction from three sediment stations along a bathymetric transect off Concepción, Chile (station 18 = 88 m water depth, station 26 = 120 m, station 40 = 1,030 m, within and below the oxygen minimum zone. All cores were collected in austral winter. Calcareous foraminifera dominated the three stations. The species composition, living foraminifera density, and vertical distribution patterns within the sediment changed in accordance with bottom water dissolved oxygen concentration and food availability. Onshore-offshore pattern revealed overall highest living foraminiferal densities at shelf stations 18 and 26 where bottom water dissolved oxygen was lowest (~ 0.2 mL-1 and content in labile organic matter highest. Within the sediment, maximum relative abundances (50-60 % of living organisms were found in the 0-1 cm interval at the organic-rich and oxygen-poor shelf stations 18 and 26. In the well-oxygenated (2.7 mL-1 slope station 40, 70 % of living foraminifera were observed deeper than the first centimeter. The number of species and the contribution of the > 250 μm fraction to the total fauna larger than 180 μm increased offshore. Nonionella auris (d'Orbigny dominated at stations 18 and 26 while a more diverse foraminifera fauna was found at station 40. This study provides the first quantitative data on living benthic foraminifera in the area; seasonal and interannual changes are not addressed.Este estudio examina la distribución costa-océano y vertical de los foraminíferos bentónicos calcáreos (fracción > 180 im vivos (teñidos en tres estaciones a lo largo de un transecto batimétrico frente al área de Concepción, Chile (estación 18 = 88 m, estación 26 = 120 m, estación 40 = 1.030 m de profundidad, dentro y bajo la zona mínima de oxígeno. Todos los testigos de sedimento fueron recolectados durante el per

  7. Disponibilidade de invertebrados aquáticos para peixes bentófagos de dois riachos da bacia do rio Iguaçu, Estado do Paraná, Brasil Aquatic invertebrates disponibility for bentophagous fishes in two streams at the Iguaçu River basin, state of Paraná, Brazil

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    Anderson Ferreira

    2002-05-01

    Full Text Available Assumindo que os organismos que os peixes consomem refletem sua disponibilidade no ambiente, os objetivos deste trabalho foram verificar, através da dieta, quais os principais organismos que compõem a bentofauna disponível para peixes bentófagos, e analisar as variações espaço-temporais e ontogenéticas na dieta deste grupo de peixes. As coletas foram realizadas mensalmente de março/2000 a fevereiro/2001 através de pesca elétrica em dois riachos da bacia do rio Iguaçu e os estômagos (n=329 analisados pelo método volumétrico. A análise da dieta revelou uma grande diversidade de invertebrados bênticos, principalmente insetos de várias ordens, sendo as mais consumidas Ephemeroptera, representada por três famílias, Diptera por onze e Trichoptera por nove famílias, sendo esses, os organismos mais disponíveis para a alimentação, além de diversos organismos menos representativos. Os resultados de correlação de Spearman foram altamente significativos, revelando forte similaridade espacial, temporal e ontogenética. Essa grande disponibilidade de recursos aquáticos, provavelmente seja a maior responsável pela elevada abundância de indivíduos do gênero Trichomycterus (Siluriformes, Trichomyspteridae nos ambientes analisados.Analyzing aquatic organisms present in fish stomachs is a good way to determine their availability in the environment. This paper aims to determine aquatic organism availability (especially benthos for bentophagous fishes and to analyze spatial, temporal and ontogenetic changes in their diets. Samples were monthly taken from March 2000 to February 2001, through electrofishing, in two streams of the Iguaçu River. The stomachs were analyzed (329 units and the results expressed through volumetric method. The diet was composed of benthic invertebrates, especially insects from several orders, being Ephemeroptera (3 families, diptera (11 families and Trichoptera (9 families the most consumed ones. Therefore

  8. Effects of cutting disturbance in Schoenoplectus californicus (C.A. Mey. Soják on the benthic macroinvertebrates = Efeito do distúrbio de corte em Schoenoplectus californicus (C.A. Mey. Soják sobre a fauna de macroinvertebrados bentônicos

    Directory of Open Access Journals (Sweden)

    Thiago Cesar Lima Silveira

    2011-01-01

    Full Text Available Lagoons are considered protected areas because these systems play a key ecological role. However, the extraction of macrophyte Schoenoplectus californicus is held for manufacture of handcrafts, being an alternative income for riverbank communities. This studyevaluated the impact of S. californicus experimental cutting on benthic macroinvertebrates trough a field experiment. Macroinvertebrates were sampled at 1, 12, 26 and 60 days after themacrophyte cutting in demarked plots (1 m², as well at control plots. The families number was not statistically different (ANOVA, p > 0.05, but the total density of invertebrates, and the density of Ceratopogonidae were significant (ANOVA, p No Brasil, as margens de lagoas são consideradas áreas protegidas por desempenharem importante papel ecológico. No entanto, a extração da macrófita Schoenoplectus californicus é realizada para a fabricação de artesanato, sendo alternativa de renda para as comunidades ribeirrinhas. Este estudo teve como objetivo avaliar o impacto do corte de S. californicus sobre os macroinvertebrados bentônicos por meio de um experimento de campo. Os macroinvertebrados foram amostrados um dia, 12, 26 e 60 dias após o corte em macrófitas em parcelas demarcadas (1 m², bem como nas parcelas-controle. As famílias de macroinvertebrados mais abundantes não apresentaram diferenças significativas (ANOVA, p < 0,05, mas a densidade total de invertebrados e a densidade de Ceratopogonidae foram significativas (ANOVA, p < 0,05 para a interação entre a data de amostragem e tratamento. A Análise de Componentes Principais identificou que a profundidade no local do experimento foi a variável que influenciou a variabilidade entre as amostras coletadas no experimento. Concluiu-seque o corte de S. californicus, nessa área, como a intensidade do corte realizado, não afeta drasticamente a composição de macroinvertebrados aquáticos. Os resultados sugerem que o extrativismo em pequenas

  9. IHF and HU: flexible architects of bent DNA.

    Science.gov (United States)

    Swinger, Kerren K; Rice, Phoebe A

    2004-02-01

    The energetic cost of bending short segments of DNA is very high. This bending is critical for the packaging of DNA and is exploited to regulate many cellular processes. In prokaryotes, IHF and HU are key architectural proteins present at high concentrations. New protein-DNA co-crystal structures, and the adaptation of advanced biophysical and biochemical techniques have led to an improved understanding of how these proteins interact with DNA. These techniques include time-resolved synchrotron X-ray footprinting, differential scanning calorimetry, isothermal titration calorimetry and single-molecule experiments.

  10. V-shaped nematogens with the "magic bent angle".

    Science.gov (United States)

    Seltmann, Jens; Müller, Kathrin; Klein, Susanne; Lehmann, Matthias

    2011-06-21

    V-shaped nematogens 1a-c and 2a-b with benzodithiophene bending units have been synthesised. The derivatives 1a-c comprise a flat core with a bending angle of 109°, which is almost the tetrahedral angle proposed to be optimal in the realization of mesogens forming a biaxial nematic thermotropic mesophase.

  11. Exact equivalent straight waveguide model for bent and twisted waveguides

    DEFF Research Database (Denmark)

    Shyroki, Dzmitry

    2008-01-01

    Exact equivalent straight waveguide representation is given for a waveguide of arbitrary curvature and torsion. No assumptions regarding refractive index contrast, isotropy of materials, or particular morphology in the waveguide cross section are made. This enables rigorous full-vector modeling o...... of in-plane curved or helically wound waveguides with use of available simulators for straight waveguides without the restrictions of the known approximate equivalent-index formulas....

  12. Bent by baryons: the low mass galaxy-halo relation

    CERN Document Server

    Sawala, Till; Fattahi, Azadeh; Navarro, Julio F; Bower, Richard G; Crain, Robert A; Vecchia, Claudio Dalla; Furlong, Michelle; Jenkins, Adrian; McCarthy, Ian G; Qu, Yan; Schaller, Matthieu; Schaye, Joop; Theuns, Tom

    2014-01-01

    The relation between galaxies and dark matter halos is of vital importance for evaluating theoretical predictions of structure formation and galaxy formation physics. We show that the widely used method of abundance matching based on dark matter only simulations fails at the low mass end because two of its underlying assumptions are broken: only a small fraction of low mass (below 10^9.5 solar masses) halos host a visible galaxy, and halos grow at a lower rate due to the effect of baryons. In this regime, reliance on dark matter only simulations for abundance matching is neither accurate nor self-consistent. We find that the reported discrepancy between observational estimates of the halo masses of dwarf galaxies and the values predicted by abundance matching does not point to a failure of LCDM, but simply to a failure to account for baryonic effects. Our results also imply that the Local Group contains only a few hundred observable galaxies in contrast with the thousands of faint dwarfs that abundance matchi...

  13. Civil Affairs Authorities Bent on Protecting People s Basic Rights

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In response to the global financial crisis,China's civil affairs au-thorities redoubled their effort in 2009 to improve the livelihood of the Chinese people and protect their basic rights and interests under the constitutional principle of respectingand protecting human rights.

  14. Experimental evidence of planar channeling in a periodically bent crystal

    CERN Document Server

    Bagli, E; Bellucci, V; Berra, E; Camattari, R; De Salvador, D; Germogli, G; Guidi, V; Lanzoni, L; Lietti, D; Mazzolari, A; Prest, M; Tikhomirov, V V; Vallazza, E

    2014-01-01

    The usage of a Crystalline Undulator (CU) has been identified as a promising solution for generating powerful and monochromatic $\\gamma$-rays. A CU was fabricated at SSL through the grooving method, i.e., by the manufacturing of a series of periodical grooves on the major surfaces of a crystal. The CU was extensively characterized both morphologically via optical interferometry at SSL and structurally via X-ray diffraction at ESRF. Then, it was finally tested for channeling with a 400 GeV/c proton beam at CERN. The experimental results were compared to Monte Carlo simulations. Evidence of planar channeling in the CU was firmly observed. Finally, the emission spectrum of the positron beam interacting with the CU was simulated for possible usage in currently existing facilities.

  15. Foraminíferos bentónicos aglutinados de los Depósitos turbidíticos. Área Nápoles, Sur de San Marcos de Tarrazú, Costa Rica Agglutinated foraminifera from turbiditic deposits, Nápoles Area, South of San Marcos, Tarrazú, Costa Rica

    Directory of Open Access Journals (Sweden)

    Lolita Campos

    2012-12-01

    Full Text Available En el sector de Nápoles, San Marcos de Tarrazú, situado dentro de una ancha faja estructural aún no completamente definida en el límite entre las cuencas sedimentarias de Valle Central y Térraba, la muestra LOR-10 brindó una asociación faunística de exclusivamente foraminíferos bentónicos. Como no fueron encontrados foraminíferos planctónicos no se pudieron realizar determinaciones bioestratigráficas. Del total de individuos identificados, estos corresponden a 3 subórdenes, 9 superfamilias y 33 especies. Con respecto al índice de diversidad de Shannon (H, para interpretaciones paleoecológicas el resultado fue de H=1.4, indicando condiciones de ciénagas y ambientes marginales marinos. Los foraminíferos bentónicos identificados hasta nivel de especie en la muestra, poseen rangos de existencia muy amplio señalando una zona que se extiende del Triásico al Reciente. Desde el punto de vista paleoecológico en relación con la salinidad, fueron determinados los siguientes porcentajes 53.3% de rotaliinos, 41.9% de texturaliinos y 2.2% de miliólidos, valores que son indicadores de ambientes de laguna salobre, estuario y plataforma, esta mezcla de fauna de ambientes distintos sugiere que se trata de un depósito alóctono retrabajado. La identificación de Portatrochammina sp. (4.3% que aparece entre los 500 y 2000 m, pero es abundante aproximadamente entre los 600 y 700 m y de Cibicides lobatulus (3.2% indicadora de la zona batial media superior (500-1500 m, confirman la interpretación del ambiente del depósito como un abanico submarino de talud del ámbito batial medio. Así mismo la preeminencia de los foraminíferos aglutinados sugiere un importante aporte de detrito hacia la cuenca. Por último, las cuencas estratificadas, frías, profundas, con altas tasas de sedimentación favorecen la preservación de las asociaciones de foraminíferos aglutinados sobre los carbonatadosIn the area of Napoles, South of San Marcos, Tarraz

  16. Development of end-bent/swept blade for multistage axial compressors; Jikuryu asshukukiyo end bent sweep yoku no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Tanino, T.; Kuromaru, M.; Furukawa, M.; Niizeki, Y.; Inoue, M. [Kyushu University, Fukuoka (Japan). Faculty of Engineering; Kinoue, Y. [Saga University, Saga (Japan). Faculty of Science and Engineering; Okuno, K. [Toshiba Corp., Tokyo (Japan)

    1999-09-20

    The endbent/swept (EBS) blades have been developed to improve the endwall boundary layer flows in middle stages of axial compressors. They have three distinctive features: the leading-edge sweep near the tip and hub to activate the annulus boundary layer flows, the leading-edge bend near the tip and hub to meet a preferable inlet flow condition, and the same exit metal angle of blade evaluated by a conventional vortex design method. The EBS and baseline blades were designed for both of the rotor and stator, and the stage performance testing was conducted in every combination of the rotor and stator in a low speed compressor test rig. The results showed that the maximum stage efficiency of the EBS rotor was higher than the baseline rotor and the considerable increase in surge margin was obtained by using the EBS rotor and stator. The effects of the EBS rotor and stator on the endwall boundary layer flows were clarified by the flow measurements downstream of the rotor and stator with a hot-wire and 5 hole-probe. (author)

  17. Study on Seismic Behavior of the Frame-Bent Hybrid Structure of SRC Columns-RC Shear Walls forthe Main Building of Thermal Power Plants%火电厂主厂房SRC柱-RC分散剪力墙框排架混合结构抗震性能研究

    Institute of Scientific and Technical Information of China (English)

    刘志钦; 白国良; 李红星; 赵春莲

    2013-01-01

    火电厂主厂房因承载的设备种类繁多,运行参数复杂,使其质量、刚度在空间和平面上分布不均匀,导致结构体系的抗震性能较差.以8度区Ⅱ类场地,单机容量1000MW机组的主厂房为研究对象,提出SRC柱-RC分散剪力墙框排架混合结构,对荷重较大的三榀子结构按1/7缩尺设计制作的模型结构,进行抗震性能试验研究,得到不同加速度峰值地震波作用下结构的荷载和位移反应,SRC柱、RC分散剪力墙的协同受力及多道抗震防线的形成规律等,并对结构在8度地震作用下的动力弹塑性分析进行对比,其结果表明该结构体系满足8度小震不坏、大震不倒的抗震设防要求,具有良好的变形性能,SRC柱与RC分散剪力墙有较好的协同工作性能,设置的RC剪力墙完美起到了第一道抗震防线作用,说明SRC柱-RC分散剪力墙框排架混合结构主厂房宜于在高烈度区大容量机组主厂房中推广应用.%As the structure of main building has many types of electric equipment, running complex parameters, with the structure system so uneven distribution of mass and stiffness has poor seismic behavior. Taking the main building with unit capacity 1000MW and at 8 degree intensity site II as research object, SCR column and RC dispersed shear wall frame-bent hybrid structural system is put forward. Three Substructures are selected and the model according to 1/7 reduced scale design is made, study to the seismic behavior. The load and displacement in different seismic waves, the coordinated working of SCR column and RC dispersed shear wall, the formation rule of multiple aseismic lines are obtained. Furthermore, the testing results are compared with the dynamic elastic-plastic analyses of model in 8 degree earthquake. The results show that the structural system can meet the needs of design in zone with the seismic fortification intensity 8, SRC frame and RC shear wall have better deformation performance and

  18. Temporal and spatial variation of rocky shores intertidal benthic communities in Southeast Brazil Variação espaço-temporal das comunidades bentônicas do entremarés de costões rochosos no Sudeste do Brasil

    Directory of Open Access Journals (Sweden)

    Gabriela C. Zamprogno

    2012-12-01

    Full Text Available The relationships between environmental factors and temporal and spatial variations of benthic communities of three rocky shores of the state of Espírito Santo, Southeast Brazil, were studied. Sampling was conducted every three months, from August 2006 to May 2007, using intersection points. Chthamalus bisinuatus (Pilsbry, 1916 (Crustacea and Brachidontes spp. (Mollusca were the most abundant taxa, occupying the upper level of the intertidal zone of the rocky shore. The species richness was higher at the lower levels. The invasive species Isognomon bicolor (C. B. Adams, 1845 (Mollusca occurred at low densities in the studied areas. The clustering analysis dendrogram indicated a separation of communities based on exposed and sheltered areas. According to the variance analyses, the communities were significantly different among the studied areas and seasons. The extent of wave exposure and shore slope influenced the species variability. The Setibão site showed the highest diversity and richness, most likely due to greater wave exposure. The communities showed greater variation in the lower levels where environmental conditions were less severe, relative to the other levels.Foram realizadas amostragens das comunidades bentônicas de médiolitoral em três costões rochosos do estado do Espírito Santo com o objetivo de estudar a variação espaço-temporal, relacionando com os fatores abióticos. Efetuaram-se coletas trimestrais entre agosto de 2006 e maio de 2007, utilizando o método de pontos de interseção. Chthamalus bisinuatus Pilsbry, 1916 (Crustacea e Brachidontes spp. (Mollusca foram os táxons mais abundantes, ocupando os níveis superiores da zona entremarés dos costões. Nas zonas inferiores ocorreu um maior número de espécies. A espécie invasora Isognomon bicolor (C.B. Adams, 1845 (Mollusca ocorreu em baixa cobertura nas áreas estudadas. O dendrograma indicou a separação das amostras das áreas expostas e abrigadas. Segundo

  19. Macroalgas bentônicas associadas a bancos de Hypnea musciformis (Wulfen J.V. Lamour. (Rhodophyta - Gigartinales em duas praias do litoral baiano Macroalgae associated with banks of Hypnea musciformis (Wulfen J.V. Lamour. (Rhodophyta, Gigartinales on two beaches on the coast of Bahia

    Directory of Open Access Journals (Sweden)

    Iara Oliveira Costa

    2012-06-01

    Full Text Available Este trabalho caracteriza a estrutura e dinâmica das comunidades de macroalgas bentônicas associadas a populações de H. musciformis ocorrentes em formações recifais nas praias de Stella Maris (Salvador e Itacimirim (Camaçari. As coletas ocorreram entre agosto de 2007 e junho de 2008. As formações recifais foram divididas em compartimentos com base no hidrodinamismo. Utilizou-se três transectos em cada compartimento, onde foram dispostos cinco quadrados de 20 x 20 cm. Foram obtidos dados de riqueza, biomassa, percentual de importância (Pi%, diversidade (H' e equitabilidade (J'. Na área estudada ocorreram 60 espécies: 30 Rhodophyta, 20 Chlorophyta e 10 Ochrophyta; biomassa média de 136 g.m-² (peso seco; e índices médios de H' e J' de 2,7 e 0,97, respectivamente. Houve predominância das rodofíceas, tanto em riqueza específica quanto em valores de biomassa. Foi encontrada maior contribuição do grupo morfo-funcional de algas corticadas. Dentre a flora associada, Gelidiella acerosa, Sargassum cymosum e Palisada perforata apresentaram maiores valores de biomassa. O compartimento recifal mais representativo em riqueza específica e biomassa foi a região frontal do recife. As comunidades das praias estudadas foram consideradas distintas devido à fisionomia das formações recifais.This study characterized the structure and dynamics of macroalgae communities associated with benthic populations of H. musciformis occurring in reef formations on the beaches of Stella Maris (Salvador and Itacimirim (Camaçari, Bahia. The samples were collected between August 2007 and June 2008. The reef formations were divided into compartments based on hydrodynamics. Three transects where made for each compartment, and each of these had five quadrants of 20 x 20cm. Data about the richness, biomass, percentage of importance (Pi%, diversity (H' and evenness (J' was collected. The study recorded 60 species, 30 Rhodophyta, 20 Chlorophyta and 10 Ochrophyta

  20. Impacto dos efluentes de cultivo semi-intensivo de camarão sobre a fauna bentônica no sul do Brasil - DOI: 10.4025/actascibiolsci.v31i4.3601 Environmental impact of semi-intensive shrimp farming on benthic fauna in southern Brazil - DOI: 10.4025/actascibiolsci.v31i4.3601

    Directory of Open Access Journals (Sweden)

    Wilson Wasielesky Junior

    2009-08-01

    Full Text Available O aumento dos cultivos em ambientes costeiros tem gerado preocupação a respeito do lançamento dos seus efluentes no ambiente aquático. Este estudo objetivou determinar o impacto dos efluentes de cultivos de camarões sobre a comunidade de macroinvertebrados bentônicos no estuário da lagoa dos Patos-Brasil. Este trabalho foi realizado numa fazenda de cultivo de camarão Litopenaeus vannamei. Como parâmetros de qualidade de água, foram monitorados quinzenalmente pH, oxigênio dissolvido, consumo de oxigênio e sólidos suspensos totais, sendo os locais de amostragem uma região-controle, saída do canal de drenagem da fazenda e bacia de sedimentação. As coletas de sedimento para a análise macrobentônica foram realizadas na saída da fazenda e no controle, e realizou-se amostragem antes do início e quinzenalmente durante o cultivo. Os resultados mostram que a bacia de sedimentação neste cultivo é relativamente eficiente. Houve reduções no pH e na concentração de oxigênio e aumento no consumo de oxigênio na saída do canal de drenagem da fazenda. Além disso, foi observada alteração na estrutura da macrofauna no ambiente adjacente ao cultivo. Ocorreu redução das espécies mais sensíveis a distúrbios Nephtys fluviatilis e Heleobia australis e flutuações na abundância de Kalliapseudes schubartiiThe increase in aquaculture activity in costal areas has raised concerns about the discharge of effluents in the aquatic environment. The aim of this study was to determine the impact of effluents from the cultivation in Patos Lagoon – Brazil, using benthic macroinvertebrates as indicators. This research was conducted in a farm of Litopenaeus vannamei shrimp. Water parameters such as pH, diluted oxygen, oxygen consumption and total suspended solids were checked every 15 days. The sampling sites were a controlled region, the farm outflow channel and the settling ponds. The sediment for analysis of the benthic was sampled in the

  1. Los macroinvertebrados bentónicos de pozo azul (Cuenca del río Gaira, Colombia y su relación con la calidad del agua The Benthonic Macroinvertebrates of Pozo Azul (Gaira River Basin, Colombia and their Relationship with Water Quality

    Directory of Open Access Journals (Sweden)

    Manjarrés-Hernández Ana

    2003-12-01

    Full Text Available En julio de 2002 se realizó el estudio de algunos parámetros fisicoquímicos y la estructura de la comunidad de macroinvertebrados bentónicos asociados a cuatro coriotipos (piedra, hojarasca, sedimento y macrófitas en el sector de Pozo Azul sobre la cuenca del río Gaira (Magdalena, Colombia. Se discute la relación entre la estructura de la comunidad y la calidad del agua del sector. Los parámetros fisicoquímicos estuvieron determinados en gran medida por las características geográficas del sistema. El agua se caracterizó por estar saturada de oxígeno y por la ausencia de compuestos intermedios de la estabilización de la materia orgánica como nitritos y amonio. Se colectaron 588 individuos distribuidos en 11 órdenes y 38 familias. Los órdenes más representativos fueron Trichoptera, Coleoptera, Diptera y Ephemeroptera, siendo el último de ellos el más abundante. Las familias más representativas fueron Baetidae, Simullidae, Perlidae, Chironomidae e Hydropsychidae, en ese mismo orden de abundancia. Para la relación de la estructura de la comunidad con la calidad del agua se calculó el índice BMWP, adaptado por la Universidad del Valle, Cali, Colombia, que estableció para este caso un agua de óptima calidad y oligosapróbita, según la ecología sapróbita, estado alcanzado luego de la estabilización frente a pequeñas alteraciones inducidas por las actividades del cultivo del café en la zona.On July 2002, a study of some physicochemical parameters and their relationship with the benthonic macroinvertebrates community structure on four coriotypes: stone, trash, silt and macrophytes, was carried out in Pozo Azul (Gaira River basin, Magdalena, Colombia. The physicochemical parameters were determined, to a considerable extent, by the geographic characteristics of the system. The water was found to be oxygen saturated, and intermediate compounds of the organic matter stabilization, such as nitrites and ammonium, there were

  2. A biodiversidade bentônica em lagoa marginal ao rio Paranapanema na zona de sua desembocadura, na represa de Jurumirim - DOI: 10.4025/actascibiolsci.v28i4.166 The benthic biodiversity in a lake marginal to the Paranapanema river in its mouth zone into Jurumirim reservoir- DOI: 10.4025/actascibiolsci.166

    Directory of Open Access Journals (Sweden)

    Rosemary Cristina Souza Davanso

    2007-11-01

    Full Text Available O presente trabalho teve como objetivo principal verificar a biodiversidade bentônica em áreas do fundo da lagoa do Coqueiral, zona de desembocadura do rio Paranapanema, na represa de Jurumirim, Estado de São Paulo. Foram selecionados dezoito pontos de amostragem, englobando áreas rasas e áreas profundas. As coletas foram feitas em intervalos trimestrais ao longo de um ano; também foram analisadas as variáveis físicas e químicas da água (nível, transparência, temperatura, oxigênio dissolvido, pH e condutividade elétrica. Amostras do sedimento, para análise da fauna e de fatores abióticos (granulometria e conteúdo orgânico, foram recolhidas em tréplicas, utilizando como coletor a draga de Petersen. O material foi triado e analisado sob microscópio estereoscópico. Contagem e identificação dos organismos foram realizadas, e densidade, abundância relativa, riqueza taxonômica e índice de dominância foram calculados. A análise revelou uma fauna com baixa diversidade e a dominância de Chironomidae e Ephemeroptera. Domínio de Ephemeroptera, constituído por Campsurus, ocorreu no período mais quente do ano e com baixa profundidade da lagoa. A distribuição dos organismos teve como principais fatores determinantes profundidade, transparência, pH e temperatura da água. Na comparação feita entre áreas rasas e profundas, foi observada uma menor densidade de organismos nas regiões profundas.Coqueiral lake is a marginal lake located at the southeast São Paulo State, in the mouth zone of the Paranapanema river into Jurumirim Reservoir and it has high connectivity with the Paranapanema river. This work aimed to verify the benthic biodiversity in areas of the lake bottom. 18 sampling sites in the lake were selected, including shallow and deep areas. The samples were taken every three months during one year. Physical and chemical water variables (level, transparency, dissolved oxygen, pH, and electric conductivity were

  3. Patterns and breaking points in the distribution of benthic algae along the temperate Pacific coast of South America Patrones y puntos de quiebre en la distribución de algas bentónicas a lo largo de la costa Pacífica de Sudamérica

    Directory of Open Access Journals (Sweden)

    ISABEL MENESES

    2000-12-01

    Full Text Available According to biogeographic studies made two decades ago, marine benthic algal species of the Pacific temperate coast of South America could be grouped into five components according to their geographic affinities. Each of these components was distributed differentially along the coastline between 4º and 56ºS and thus, their contribution to the overall flora varied depending on the latitude. Species composition changed at specific latitudes in such a way that three groups could be observed: from 4 to 6ºS, from 6 to 30ºS and from 30 to 55ºS. Since 1980, new information on marine algae along this coastline allows a review of the previous phytogeographic characterization. The presence/absence of algal species, separated by division and geographic affinity, was recorded for each degree of latitude from 4º to 56ºS and used to analyze the similarity in species composition and possible changes in distribution patterns. Results show the same five geographic components detected 20 years ago with similar distributions. Differences observed are a further southward intrusion of subtropical elements, a decrease in endemic species number and relative contribution to the flora at the southern tip of South America, and two breaking points in species composition at 12º and 42ºS. Another two breaking points occur at 20ºS and at 33ºS in Phaeophyta and Rhodophyta species composition respectively. The inclusion of single-record species does not affect significantly the distribution of species along this coastlineDe acuerdo a estudios biogeográficos realizados hace 20 años, las especies de algas marinas bentónicas de la costa temperada del Pacífico de Sudamérica se agrupan en 5 componentes de distinta afinidad geográfica. Cada uno de estos componentes posee una distribución diferencial a lo largo de estas costas entre los 4º y los 55ºS. De esta forma su contribución a la flora varía dependiendo de la latitud. La composición de las especies

  4. Ecological attributes of the benthic community and indices of water quality in urban, rural and preserved environments Atributos ecológicos da comunidade bentônica e índices de qualidade da água de ambientes urbanos, rurais e preservados

    Directory of Open Access Journals (Sweden)

    Claudia Eiko Yoshida

    2012-09-01

    as alterações da paisagem dos riachos e de seu entorno com as mudanças na estrutura da comunidade de macroinvertebrados desses ambientes; OBJETIVOS: O presente estudo teve como objetivos correlacionar as mudanças da paisagem com os atributos ecológicos da comunidade e índices de qualidade da água e, recomendar valores de condição referencial de integridade de riachos para a região de Jundiaí/SP; MÉTODOS: Foram amostradas a fauna bentônica de três riachos urbanos, três rurais e três preservados, com amostrador do tipo Surber, em julho de 2010. As características da paisagem foram avaliadas por meio da Diversidade de Habitat (DH; a comunidade, analisada quanto a S, N, J', H' e curvas de rarefação S e de dominância K e; a qualidade da água aferida pelos índices ICB Rio, BMWP-CETEC, ASPT e SOMI; RESULTADOS: A estrutura e a composição das comunidades variaram em função dos riachos e refletiram-se nos valores dos índices biológicos e de qualidade ambiental. As melhores condições foram encontradas nos riachos preservados, as intermediárias, nos riachos rurais e, as piores, nos urbanos. As significativas correlações (r > 0.73 e P < 0.05 entre o índice de diversidade de habitat (DH e os atributos ecológicos e de qualidade da água dos riachos de Jundiaí, demonstraram que DH pode ser um bom preditor das características ambientais avaliadas e como tal, recomenda-se como valores de condição de referencia de riachos: DH ≥ 80; H' ≥ 2,3 e J ≥ 0.8 (família como nível taxonômico e; qualidade de água boa (ICB Rio, BMWP-CETEC e BI, de levemente poluída a limpa (ASPT e regular (SOMI.

  5. Ecological attributes of the benthic community and indices of water quality in urban, rural and preserved environments Atributos ecológicos da comunidade bentônica e índices de qualidade da água de ambientes urbanos, rurais e preservados

    Directory of Open Access Journals (Sweden)

    Claudia Eiko Yoshida

    2012-01-01

    as alterações da paisagem dos riachos e de seu entorno com as mudanças na estrutura da comunidade de macroinvertebrados desses ambientes; OBJETIVOS: O presente estudo teve como objetivos correlacionar as mudanças da paisagem com os atributos ecológicos da comunidade e índices de qualidade da água e, recomendar valores de condição referencial de integridade de riachos para a região de Jundiaí/SP; MÉTODOS: Foram amostradas a fauna bentônica de três riachos urbanos, três rurais e três preservados, com amostrador do tipo Surber, em julho de 2010. As características da paisagem foram avaliadas por meio da Diversidade de Habitat (DH; a comunidade, analisada quanto a S, N, J', H' e curvas de rarefação S e de dominância K e; a qualidade da água aferida pelos índices ICB Rio, BMWP-CETEC, ASPT e SOMI; RESULTADOS: A estrutura e a composição das comunidades variaram em função dos riachos e refletiram-se nos valores dos índices biológicos e de qualidade ambiental. As melhores condições foram encontradas nos riachos preservados, as intermediárias, nos riachos rurais e, as piores, nos urbanos. As significativas correlações (r > 0.73 e P < 0.05 entre o índice de diversidade de habitat (DH e os atributos ecológicos e de qualidade da água dos riachos de Jundiaí, demonstraram que DH pode ser um bom preditor das características ambientais avaliadas e como tal, recomenda-se como valores de condição de referencia de riachos: DH ≥ 80; H' ≥ 2,3 e J ≥ 0.8 (família como nível taxonômico e; qualidade de água boa (ICB Rio, BMWP-CETEC e BI, de levemente poluída a limpa (ASPT e regular (SOMI.

  6. "Forlagbranchen satser på de unges sprog" interview med Bent Fausing af Naj Helen Hertzum

    DEFF Research Database (Denmark)

    Fausing, Bent

    2009-01-01

    Om afsmitningen af sms sprog på det almindelige sprog, samt afsmitningen af billedbeskeder og digitale fotostreams på Social Network Sites (Twitter, Facebook, Fælickr etc.) på æstetikken og kunsten i det hele taget.......Om afsmitningen af sms sprog på det almindelige sprog, samt afsmitningen af billedbeskeder og digitale fotostreams på Social Network Sites (Twitter, Facebook, Fælickr etc.) på æstetikken og kunsten i det hele taget....

  7. 访谈HEGEL(音响哲学)主设计师BENT HOLTER

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    HEGEL(音响哲学)是一个来自挪威的Hi—End品牌,总部位于挪威首都奥斯陆,具有独立的研发中心,主设计师是BENTHOLTER。HEGEL认为:好的器材应该能忠实地还原软件中本来的信息,既不应该添加什么,也不应丢失什么,声音不应有明显的人为色彩,力求自然、透明、准确、平衡。不久前,他来到了广州,

  8. A technique for measuring the quality of an elliptically bent pentaerythritol [PET(002)] crystal

    Science.gov (United States)

    Haugh, M. J.; Jacoby, K. D.; Barrios, M. A.; Thorn, D.; Emig, J. A.; Schneider, M. B.

    2016-11-01

    We present a technique for determining the X-ray spectral quality from each region of an elliptically curved PET(002) crystal. The investigative technique utilizes the shape of the crystal rocking curve which changes significantly as the radius of curvature changes. This unique quality information enables the spectroscopist to verify where in the spectral range that the spectrometer performance is satisfactory and where there are regions that would show spectral distortion. A collection of rocking curve measurements for elliptically curved PET(002) has been built up in our X-ray laboratory. The multi-lamellar model from the XOP software has been used as a guide and corrections were applied to the model based upon measurements. But, the measurement of RI at small radius of curvature shows an anomalous behavior; the multi-lamellar model fails to show this behavior. The effect of this anomalous RI behavior on an X-ray spectrometer calibration is calculated. It is compared to the multi-lamellar model calculation which is completely inadequate for predicting RI for this range of curvature and spectral energies.

  9. 'Gewoon worden wie je bent': Over authenticiteit en anti-institutionalisme

    NARCIS (Netherlands)

    S.D. Aupers (Stef); D. Houtman (Dick); I. van der Tak

    2003-01-01

    textabstractAnalysis of a dozen semi-structured interviews with Dutch New Age trainers demonstrates that the modern 'ethics of authenticity' underlies contemporary society's anti-institutional mood. All institutions, be they traditional or modern, or so our respondants argue, prevent one from being

  10. Field Plot and Accuracy Assessment Points for Bent's Old Fort National Historic Site Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — Accuracy Assessment, Observation and Plot Points. Plots within the park were identified and sampled in the summer of 2005. In the summer of 2006, randomly selected...

  11. Hierarchical models for failure analysis of plates bent by distributed and localized transverse loadings

    Institute of Scientific and Technical Information of China (English)

    Erasmo CARRERA; Gaetano GIUNTA

    2008-01-01

    The failure analysis of simply supported, isotropic, square plates is addressed. Attention focuses on minimum failure load amplitudes and failure locations, von Mises' equivalent stress along the plate thickness is also addressed. Several distributed and localized loading conditions are considered. Loads act on the top of the plate. Bi-sinusoidal and uniform loads are taken into account for distributed loadings, while stepwise constant centric and off-centric loadings are addressed in the case of localized loadings. Analysis is performed considering plates whose length-to-thickness ratio a/h can be as high as 100 (thin plates) and as low as 2 (very thick plates). Results are obtained via several 2D plate models. Classical theories (CTs) and higher order models are applied. Those theories are based on polynomial approximation of the displacement field. Among the higher order theories (HOTs), HOTsd models account for the transverse shear deformations, while HOTs models account for both transverse shear and transverse normal deformations. LHOTs represent a local application of the higher order theories. A layerwise approach is thus assumed: by means of mathematical interfaces, the plate is considered to be made of several fictitious layers. The exact 3D solution is presented in order to determine the accuracy of the results obtained via the 2D models. In this way a hierarchy among the 2D theories is established. CTs provide highly accurate results for a/h greater than 10 in the case of distributed loadings and greater than 20 for localized Ioadings. Results obtained via HOTs are highly accurate in the case of very thick plates for bi-sinusoidal and centric loadings. In the case of uniform and off-centric loadings a high gradient is present in the neighborhood of the plate top. In those cases, LHOTs yield results that match the exact solution.

  12. Macroalgas bentónicas de la laguna de Tampamachoco, Veracruz, México

    OpenAIRE

    Kurt M. Dreckmann; Pérez-Hemández, Marco A

    2016-01-01

    A total of 23 macroalgal species were identified in Laguna Tampamachoco, Veracruz, Mexico: 9 ChIorophyceae, 2 Phaeophyceae and 12 Rhodophyceae. Algal richness per area is relatively higher (60-100 times) than in another coastal lagoon and one estuary of the area (Laguna Madre and Tamiahua with 29 and 22 species respectively). We report the presence of Phaeophyceae in this environment for the first time. The three sites have 58 species in total, twice the number reported from any other North A...

  13. Klimop 1, Nut en schadelijkheid : je bent onvoorwaardelijk vóór of faliekant tegen

    NARCIS (Netherlands)

    Kopinga, J.

    2008-01-01

    Dit artikel is het eerste in een serie van drie over de toepassing en het beheer van klimop. Het is gebaseerd op het rapport Klimop in het stedelijk groen, dat schrijver dezes opstelde op verzoek van stadsdeel Amsterdam-Noord. Dit eerste deel gaat over het nut en de schadelijkheid van klimop en de b

  14. Hell-Bent on Force Protection: Confusing Troop Welfare With Mission Accomplishment in Counterinsurgency

    Science.gov (United States)

    2009-01-01

    accessed February 25,2009). Downey, Robert ; Lee Grubbs, Brian Malloy , and Craig Wonson. "How Should the U.S. Execute a Surge in Afghanistan?" Small Wars...survival rate against lED and mine attacks, with the Marines reporting to Secretary of Defense Robert Gates in 2006 that no Marines had been killed...Krepinevich, 4-5. 43 Robert Cassidy, "Back to the Street Without Joy: Counterinsurgency Lessons from Vietnam and Other Small Wars," Parameters, (Summer 2004

  15. NMR studies of bent DNA using {sup 13}C-enriched samples

    Energy Technology Data Exchange (ETDEWEB)

    Zimmer, D.P.; Crothers, D.M. [Yale Univ., New Haven, CT (United States)

    1994-12-01

    Bending of the DNA double helix can be brought about by introducing runs of adenines (A-tracts) in phase with the helical repeat of the DNA. The requirements for bending of DNA by A-tracts are that the length of the A-tract be greater than 3 base pairs and that the A-tracts must be in phase with the helical repeat (every 10 or 11 bp). Other factors, such as the number of adenines in the run, flanking sequences, and whether the A-tracts are phased with respect to the 5{prime}A or the 3{prime}A, have effects upon the degree of bending as assayed by electrophoretic mobility on native polyacrylamide gels. There are a number of models for bending A-tract DNA. The junction-bending model postulates that the structure of A-tracts is similar to the fiber diffraction structure of poly A, in which there is a significant degree of base pair tilt with respect to the helix axis. In this model, bending occurs at the junction between the A-tract and the B-form helix to allow favorable stacking interactions to occur. The bend of the helix could arise as a result of some other perturbation of B-form DNA by A-tracts, such as propeller twist; bending also could be due to a combination of factors. Our goal is to find the structural features of A-tracts responsible for bending of the helix by performing NMR on oligonucleotides containing A-tracts to obtain higher resolution structural data. One of the problems encountered in NMR structure determination of nucleic acids and other macromolecules is the assignment of resonances to nuclei. This procedure can be greatly facilitated through the use of {sup 13}C-enriched nucleic acid samples. We are developing a technique for the enzymatic synthesis of labeled DNA for NMR. The technique we are developing is similar to RNA labeling techniques already in use. The technique involves growth of methylotrophic bacteria on {sup 13}CH{sub 3}OH.

  16. Measurement of Short Living Baryon Magnetic Moment using Bent Crystals at SPS and LHC

    CERN Document Server

    Burmistrov, L; Ivanov, Yu; Massacrier, L; Robbe, P; Scandale, W; Stocchi, A

    2016-01-01

    The magnetic moments of baryons containing u,d and s quarks have been extensively studied and measured. The experimental results are all obtained by a well-assessed method that consists in measuring the polarisation vector of the incoming particles and the precession angle when the particle is travelling through an intense magnetic field. The polarization is evaluated by analysing the angular distribution of the decay products. No measurement of magnetic moments of charm or beauty baryons (and τ leptons) has been performed so far. The main reason is the lifetimes of charm/beauty baryons, too short to measure the magnetic moment by standard techniques. Historically, the prediction of baryon magnetic moments was one of the striking successes of the quark model. The importance of the measurement of heavy quark magnetic moment is to test the possibility that the charmed and/or beauty quarks has an anomalous magnetic moment, arising if those quarks are composite objects. Measurements on magnetic moments of heav...

  17. Steering efficiency of a ultrarelativistic proton beam in a thin bent crystal

    CERN Document Server

    Bagli, Enrico; Guidi, Vincenzo; Mazzolari, Andrea; De Salvador, Davide; Berra, Alessandro; Lietti, Daniela; Prest, Michela; Vallazza, Erik

    2013-01-01

    Crystals with small thickness along the beam exhibit top performance for steering particle beams through planar channeling. For such crystals, the effect of nuclear dechanneling plays an important role because it affects their efficiency. We addressed the problem through experimental work carried out with 400 GeV/c protons at fixed-target facilities of CERN-SPS. The dependence of efficiency vs. curvature radius has been investigated and compared favourably to the results of modeling. A realistic estimate of the performance of a crystal designed for LHC energy including nuclear dechanneling has been achieved.

  18. Volume reflection and channeling of ultrarelativistic protons in germanium bent single crystals

    CERN Document Server

    Bellucci, S

    2016-01-01

    The paper devoted to investigation of volume reflection and channeling processes of ultrarela- tivistic positive charged particles moving in germanium single crystals. We demonstrate that the choice of atomic potential on the basis of Hartree-Fock method and correct choice of Debye tem- perature allow us to describe the above mentioned processes in a good agreement with the recent experiments. Moreover, the presented in the paper universal form of equations for volume reflection gives true description of the process at a wide range of particle energies. Standing on this study we make predictions for mean angle reflection (as a function of bending radius) of positive and negative particles for germanium (110) and (111) crystallographic planes.

  19. 75 FR 57289 - Notice of Inventory Completion: Pioneer Historical Society of Bent County, Las Animas, CO

    Science.gov (United States)

    2010-09-20

    ..., CO AGENCY: National Park Service, Interior. ACTION: Notice. Notice is here given in accordance with... Animas, CO. The human remains were removed from unknown locations. This notice is published as part of..., New Mexico; Pueblo of Santo Domingo, New Mexico; Pueblo of Taos, New Mexico; Pueblo of Tesuque,...

  20. Neutrophil recruitment limited by high-affinity bent β2 integrin binding ligand in cis.

    Science.gov (United States)

    Fan, Zhichao; McArdle, Sara; Marki, Alex; Mikulski, Zbigniew; Gutierrez, Edgar; Engelhardt, Britta; Deutsch, Urban; Ginsberg, Mark; Groisman, Alex; Ley, Klaus

    2016-08-31

    Neutrophils are essential for innate immunity and inflammation and many neutrophil functions are β2 integrin-dependent. Integrins can extend (E(+)) and acquire a high-affinity conformation with an 'open' headpiece (H(+)). The canonical switchblade model of integrin activation proposes that the E(+) conformation precedes H(+), and the two are believed to be structurally linked. Here we show, using high-resolution quantitative dynamic footprinting (qDF) microscopy combined with a homogenous conformation-reporter binding assay in a microfluidic device, that a substantial fraction of β2 integrins on human neutrophils acquire an unexpected E(-)H(+) conformation. E(-)H(+) β2 integrins bind intercellular adhesion molecules (ICAMs) in cis, which inhibits leukocyte adhesion in vitro and in vivo. This endogenous anti-inflammatory mechanism inhibits neutrophil aggregation, accumulation and inflammation.

  1. Unravelling the mechanism behind Swirl-Switching in turbulent bent pipes

    Science.gov (United States)

    Schlatter, Philipp; Hufnagel, Lorenz; Canton, Jacopo; Örlü, Ramis; Marin, Oana; Merzari, Elia

    2016-11-01

    Turbulent flow through pipe bends has been extensively studied, but several phenomena still miss an exhaustive explanation. Due to centrifugal forces, the fluid flowing through a curved pipe forms two symmetric, counter-rotating Dean vortices. It has been observed, experimentally and numerically, that these vortices change their size, intensity and axis in a periodic, oscillatory fashion, a phenomenon known as swirl-switching. These oscillations are responsible for failure due to fatigue in pipes, and their origin has been attributed to a recirculation bubble, disturbances coming from the upstream straight section and others. The present study tackles the problem by direct numerical simulations (DNS) analysed, for the first time, with three-dimensional proper orthogonal decomposition (POD) as to distinguish between the spatial and temporal contributions. The simulations are performed at a friction Reynolds number of about 360 with a divergence-free synthetic turbulence inflow, as to avoid the interference of low-frequency oscillations generated by a standard recycling method. Results indicate that a single low-frequency, three-dimensional POD mode, representing a travelling wave, and previously mistaken by 2D POD for two different modes, is responsible for the swirl-switching.

  2. Crack prevention of highly bent metal thin films in woven electronic textiles

    Science.gov (United States)

    Kinkeldei, T.; Cherenack, K.; Zysset, C.; Woo, N. C.; Tröster, G.

    2011-08-01

    Recent smart textile fabrication methods that are aimed at increasing the integration of electronics with textiles have involved fabricating micro-electronic components directly at the yarn level. Our approach to creating smart textiles is to fabricate thin-film devices and interconnects on plastic strips to create `e-fibers' and weave them into a textile using a commercial weaving machine. e-Fibers are exposed to bending radii as small as 165 μm during weaving. If patterned interconnect lines and device layers on the surface of the e-fiber are not designed correctly, they will crack due to the high strain and lose their electronic functionality. Brittle sensor and transistor device layers may be protected locally using rigid encapsulation materials, but cracking remains an issue for long metal interconnect lines which require flexibility. We investigated two strain-control methods to prevent the thin-film interconnect lines from cracking during weaving: (1) patterning the metal interconnect lines with a geometric design to slow propagation and merging of cracks and (2) encapsulation of interconnect lines to shift the deposited films to the neutral plain of the substrate. The mechanical behavior of interconnect lines exposed to tensile bending was studied by measuring the change in interconnect resistance versus bending radii ranging from 5 mm to 50 μm. The critical bending radius, XC, defined as the radius at which the normalized interconnect resistance changes to 1.1 (indicating the onset of film rupturing) was 150 μm for standard interconnect lines. Patterned interconnect lines had a radius XC of 115 μm while encapsulated interconnect lines never reached this critical bending radius and showed a maximum resistance change of 1.02 at 100 μm. These results show that it is possible to design interconnect lines with reduced cracking behavior when exposed to high strain during commercial weaving.

  3. A technique for measuring the quality of an elliptically bent pentaerythritol [PET(002)] crystal.

    Science.gov (United States)

    Haugh, M J; Jacoby, K D; Barrios, M A; Thorn, D; Emig, J A; Schneider, M B

    2016-11-01

    We present a technique for determining the X-ray spectral quality from each region of an elliptically curved PET(002) crystal. The investigative technique utilizes the shape of the crystal rocking curve which changes significantly as the radius of curvature changes. This unique quality information enables the spectroscopist to verify where in the spectral range that the spectrometer performance is satisfactory and where there are regions that would show spectral distortion. A collection of rocking curve measurements for elliptically curved PET(002) has been built up in our X-ray laboratory. The multi-lamellar model from the XOP software has been used as a guide and corrections were applied to the model based upon measurements. But, the measurement of RI at small radius of curvature shows an anomalous behavior; the multi-lamellar model fails to show this behavior. The effect of this anomalous RI behavior on an X-ray spectrometer calibration is calculated. It is compared to the multi-lamellar model calculation which is completely inadequate for predicting RI for this range of curvature and spectral energies.

  4. Bent Crystal Monochromator with Constant Crystal Center Position and 2-theta Arm for a Dispersive Beamline

    Science.gov (United States)

    Neuenschwander, Regis T.; Tolentino, Hélio C. N.

    2004-05-01

    For the new LNLS dispersive beam line it was designed a single-crystal monochromator and a 2-theta arm. The monochromator uses a new bender design assembled on the top of an in-vacuum HUBER goniometer. This bender is able to apply independent torque on each extremity of the crystal in a way that changes in the curvature radius do not affect the position of the center of the crystal. It also has a twist mechanism, based on eccentric bearings and elastic components. The crystal extremities are clamped to the bender using two water-cooled copper blocks, for thermal stabilization. All the bender's movements are done with vacuum compatible stepping-motors. The vacuum chamber was built with enough space to allow future installation of another bender for crystals with different Bragg planes. The internal mechanics is isolated from the vacuum chamber and can move up and down with three high precision jacks. The design of the 2-theta arm is based on two linear translation stages and some special bearings. The two stages are equipped with linear encoders, ball screws end linear bearings. With a proper alignment procedure, it is possible to find the equations that controls each translation stage in order to get a virtual rotation referenced to the monochromator center. The main arm is composed of a steel frame, a 3m long granite block, a central aluminum optical rail and two auxiliary side rails.

  5. Estrutura de comunidades bentónicas sob pressão de pesca de arrasto

    OpenAIRE

    Alves, Fábio Rui Lima

    2014-01-01

    Over time, fishing techniques improved as a response to the needs of Human populations. Alongside with the increase of fishing activities important changes in the marine ecosystems were also observed (e.g. overexploitation of stocks and habitat loss or degradation). Overfishing, bycatch, discards and ghost-fishing are some of the most discussed impacts of fishing activities, but the effect of bottom trawling should not be underestimated, since it has been proven to have a significant impac...

  6. Spatial Vegetation Data for Bent's Old Fort National Historic Site Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — High resolution vegetation polygons mapped by the National Park Service. A total of 800 acres (324 ha) were mapped. Thirteen map classes were used to describe the...

  7. Stretch bent forming technology for the bent stainless steel roof beams on railcars%轨道车辆不锈钢车顶弯梁拉弯成形技术

    Institute of Scientific and Technical Information of China (English)

    王锋; 谷诤巍; 刘玉梅; 刘志泰; 赵亚夫

    2007-01-01

    介绍了拉弯成形专用模拟软件PS2F(Profile Stretch 2D Forming),运用该软件对北京地铁5号线不锈钢车体车顶弯梁的拉弯成形工艺进行数值模拟分析,消除了起皱等成形缺陷,开发出高精度拉弯模具.

  8. Dynamic stability of a curved pipe bent in the arc of a circle on hinge supports at the ends

    Indian Academy of Sciences (India)

    D S Lolov; S V Lilkova-Markova

    2006-10-01

    Curved pipes conveying fluids are investigated in the paper. Methods of numerical solution of the dynamic stability of a pipe in its plane are developed. An example of a curved pipe is solved by these methods. A non-dimensional parameter of flow velocity and a non-dimensional circular frequency are obtained.

  9. Biótopos de foraminíferos bentónicos da plataforma continental portuguesa

    OpenAIRE

    2014-01-01

    Este trabalho enquadra-se no Projeto ACOSHELF (Coastal Shelf Studies Ecosystems Studies Using Acoustics). O programa de amostragem ocorreu em Abril/Maio de 2008. As amostras de sedimentos superficiais foram recolhidas com uma draga Smith-McIntyre (com 0,1m2). Para este trabalho foram selecionadas 46 amostras, recolhidas ao longo de transeptos perpendiculares à linha de costa, entre profundidades de 15 m a 190 m. Os sedimentos foram caracterizados em termos de granulometria e conteúdo em ma...

  10. Momentum-space spectroscopy for advanced analysis of dielectric-loaded surface plasmon polariton coupled and bent waveguides

    CERN Document Server

    Hassan, K; Bernardin, T; Colas-des-Francs, G; Weeber, Jean-Claude; de Lamestre, R Espiau; Dereux, Alain

    2013-01-01

    We perform advanced radiation leakage microscopy of routing dielectric-loaded plasmonic waveguiding structures. By direct plane imaging and momentum-space spectroscopy, we analyze the energy transfer between coupled waveguides as a function of gap distance and reveal the momentum distribution of curved geometries. Specifically, we observed a clear degeneracy lift of the effective indices for strongly interacting waveguides in agreement with coupled-mode theory. We use momentum-space representations to discuss the effect of curvature on dielectric-loaded waveguides. The experimental images are successfully reproduced by a numerical and an analytical model of the mode propagating in a curved plasmonic waveguide.

  11. Bent Metal in a Bone: A Rare Complication of an Emergent Procedure or a Deficiency in Skill Set?

    Directory of Open Access Journals (Sweden)

    Mridula Krishnan

    2016-01-01

    Full Text Available Intraosseous (IO access is an important consideration in patients with difficult intravenous (IV access in emergent situations. IO access in adults has become more popular due to the ease of placement and high success rates. The most common sites of access include the proximal tibia and the humeral head. The complications associated are rare but can be catastrophic: subsequent amputation of a limb has been described in the literature. We report a 25-year-old female presenting with diabetic ketoacidosis (DKA in whom emergent IO access was complicated by needle bending inside the humerus. Conventional bedside removal was impossible and required surgical intervention in operating room.

  12. Optimization of bent perfect Si(220)-crystal monochromator for residual strain/stress instrument-Part II

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Myung-Kook [Neutron Beam Application, Korea Atomic Energy Research Institute, 150 Duckjin-Dong, Yusung, Daejon 305-600 (Korea, Republic of)]. E-mail: moonmk@kaeri.re.kr; Em, Vyacheslav T. [Neutron Beam Application, Korea Atomic Energy Research Institute, 150 Duckjin-Dong, Yusung, Daejon 305-600 (Korea, Republic of); Lee, Chang-Hee [Neutron Beam Application, Korea Atomic Energy Research Institute, 150 Duckjin-Dong, Yusung, Daejon 305-600 (Korea, Republic of); Mikula, Pavol [Nuclear Physics Institute and Research Centre Rez Ltd., 250 68 Rez (Czech Republic); Hong, Kwang-Pyo [Neutron Beam Application, Korea Atomic Energy Research Institute, 150 Duckjin-Dong, Yusung, Daejon 305-600 (Korea, Republic of); Choi, Young-Hyun [Neutron Beam Application, Korea Atomic Energy Research Institute, 150 Duckjin-Dong, Yusung, Daejon 305-600 (Korea, Republic of); Cheon, Jong-Kyu [Neutron Beam Application, Korea Atomic Energy Research Institute, 150 Duckjin-Dong, Yusung, Daejon 305-600 (Korea, Republic of); Nam, Uk-Won [Nuclear Physics Institute and Research Centre Rez Ltd., 250 68 Rez (Czech Republic); Kong, Kyung-Nam [Nuclear Physics Institute and Research Centre Rez Ltd., 250 68 Rez (Czech Republic); Korea Astronomy Observatory, Yusung, Daejeon 305-348 (Korea, Republic of); Jin, Kyung-Chan [Korea Institute of Industrial Technology, 35-3 Hongchon-Ri, Ipchang-Myun, Chonan-Si, Chungnam, 330-825 (Korea, Republic of)

    2005-11-01

    Optimized diffractometer arrangements for residual strain measurements employing curved crystal monochromators provide good luminosity and a high {delta}d/d resolution in the vicinity of usually used scattering angle 2{theta}{sub S}{approx}+/-90{sup o}. Due to a variety of designs of the diffractometers which could be installed at a constant or different take-off angles, except a few attempts, there is a lack of experimental evidence providing a help in a choice of parameters for an optimum performance. In addition to our earlier investigations with curved Si(311) monochromator employed in different diffraction geometries (see paper I [M.K. Moon et al., Physica B, submitted [1

  13. Successful Percutaneous Coronary Intervention through a Severely Bent Artificial Ascending Aorta Using the DIO Thrombus Aspiration Catheter

    Directory of Open Access Journals (Sweden)

    Akinori Fujikake

    2016-01-01

    Full Text Available A 66-year-old man was admitted to our institute because of chest pain. He had undergone replacement of the ascending aorta due to aortic dissection 9 years previously. We made a diagnosis of acute coronary syndrome, and coronary artery angiography was performed. Although the right coronary artery was successfully cannulated, a severe bend of the artificial aorta made it very difficult to advance the catheter into the left coronary artery. Ultimately, a DIO thrombus aspiration catheter was used to enter the left coronary artery, and a stent was implanted successfully. The DIO catheter is very useful when the selection of a guiding catheter is complicated, such as in the case of severe vessel tortuosity or a bend of the ascending aorta.

  14. Evaluative Testing of the Bent Canyon Stage Station on the Pinon Canyon Maneuver Site, Las Animas County, Colorado

    Science.gov (United States)

    2005-01-01

    Boulder. Chapman, J. A., J. G. Hockman and W. R. Edwards 1982 Cottontails: Sylvilagus floridanus and Allies. In Wild Mammals of North America: Biology ...Smith, R. L. 1980 Ecology and Field Biology . Harper and Row, New York. South, S. 1978 Exploring Analytical Technique. In Historical Archaeology: A...page 1 of • ACC# " EXCAVATON LEVEL FORM Fort Carson-Pifion Canyon Maneuver Site Proj ect . Stage 7 Site ,L-131 75 Unit Z X•o ALevel Screen size 4

  15. Nonsymmetric bent-core liquid crystals based on a 1,3,4-thiadiazole core unit and their nematic mesomorphism

    Energy Technology Data Exchange (ETDEWEB)

    Seltmann, Jens; Marini, Alberto; Mennucci, Benedetta; Dey, Sonal; Kumar, Satyendra; Lehmann, Matthias (Wurzburg); (Kent); (Chemnitz)

    2012-09-06

    The synthesis and thermotropic properties of novel V-shaped molecules having a central 1,3,4-thiadiazole core with a bend-angle of 160 degrees are reported. The compounds consist of a shape-persistent oligo(phenylene ethynylene) scaffold with lateral alkyloxy substituents. One of the terminal aromatic units possesses an alkoxy chain capped by an ethyl ester group while the second terminus is a pyridyl group. They exhibit enantiotropic nematic phases and are characterized by polarized optical microscopy, differential scanning calorimetry, and X-ray diffraction. Results from conoscopy indicate a biaxial nature of the nematic phase near room temperature. DFT calculations of dipole moments and molecular polarizabilities are used to substantiate the experimental findings.

  16. National Agriculture Imagery Program (NAIP) Digital Ortho Imagery for Bent's Old Fort National Historic Site Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — This data set contains imagery from the National Agriculture Imagery Program (NAIP). NAIP acquires digital ortho imagery during the agricultural growing seasons in...

  17. Effect of closure of collinear cracks on the stress-strain state and the limiting equilibrium of bent shallow shells

    Science.gov (United States)

    Shatskii, I. P.; Makoviichuk, N. V.

    2011-05-01

    The problem of closure of collinear cracks during bending of a shallow shell is considered within the framework of the Kirchhoff theory. Crack closure is described using the model of contact along a line on one of the shell faces. Strain and moment intensity factors and fracture load are studied as functions of shell curvature and defect location, and the distribution of contact forces along the cracks is investigated.

  18. Social return: zó bent u er klaar voor : do’s en don’ts voor MKB

    NARCIS (Netherlands)

    Walhof, Gert

    2013-01-01

    Aanbevelingen voor het MKB. ​MKB'ers kunnen hun concurrentiepositie versterken door goed voorbereid te zijn op Social Return. Social Return wil zeggen dat opdrachtgevers zoals gemeenten voorwaarden in aanbestedingen opnemen waarbij ze van ondernemers vragen om mensen met een afstand tot de arbeidsma

  19. Vector Finite Element Modeling of the Full-Wave Maxwell Equations to Evaluate Power Loss in Bent Optical Fibers

    Energy Technology Data Exchange (ETDEWEB)

    Koning, J; Rieben, R; Rodrigue, G

    2004-12-09

    We measure the loss of power incurred by the bending of a single mode step-indexed optical fiber using vector finite element modeling of the full-wave Maxwell equations in the optical regime. We demonstrate fewer grid elements can be used to model light transmission in longer fiber lengths by using high-order basis functions in conjunction with a high order energy conserving time integration method. The power in the core is measured at several points to determine the percentage loss. We also demonstrate the effect of bending on the light polarization.

  20. Determination of the properties of cereal stalks when being bent and cut with the aid of a universal test bench

    Directory of Open Access Journals (Sweden)

    Andrej Batos

    2015-07-01

    Full Text Available Für die Messung der Biege- und Schnitteigenschaften halmartiger Güter wurde ein Universalprüfstand entworfen. Die mit ihm ermittelten Messwerte dienen der Erstellung von Simulationsmodellen zur Abbildung landtechnischer Schnittprozesse. In der vorliegenden Studie werden Weizenhalme untersucht. Die Schnittversuche erfolgen mit zwei Geschwindigkeiten und zwei Schnittwinkeln. Die Mittelwerte aus jeweils 50 Messungen werden miteinander verglichen. Der Feuchtigkeitsgehalt der Proben liegt zwischen 5,5 und 7,1 %. Die Biegespannungen betragen für das erste Internodium 1,09 N/mm², für das zweite 0,99 N/mm² und für das dritte 1,07 N/mm². Bei den Schnittversuchen tritt die höchste Spannung (4,44 N/mm² beim Schneiden des zweiten Internodiums auf (50 mm/s, 40°. Die niedrigste Spannung (2,20 N/mm² tritt beim Schneiden des dritten Internodiums auf (150 mm/s, 60°. Bis auf eine Ausnahme ist die auf den Probenquerschnitt bezogene Schnittenergie (12,18–19,85 mJ/mm² bei der Auswahl des größeren Winkels höher. Die mittleren Variationskoeffizienten liegen zwischen 5 und 32 %.

  1. Focusing X-rays to a 1-{mu}m spot using elastically bent, graded multilayer coated mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Underwood, J.H.; Thompson, A.C.; Kortright, J.B. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    In the x-ray fluorescent microprobe at beamline 10.3.1, the ALS bending magnet source is demagnified by a factor of several hundred using a pair of mirrors arranged in the Kirkpatrick-Baez (K-B) configuration. These are coated with multilayers to increase reflectivity and limit the pass band of the x-rays striking the sample. The x-rays excite characteristic fluorescent x-rays of elements in the sample, which are analyzed by an energy dispersive Si-Li detector, for a sensitive assay of the elemental content. By scanning the focal spot the spatial distribution of the elements is determined; the spatial resolution depends on the size of this spot. When spherical mirrors are used, the spatial resolution is limited by aberrations to 5 or 10 {mu}m. This has been improved to 1 {mu}m through the use of an elliptical mirror formed by elastically bending a plane mirror of uniform width and thickness with the optimum combination of end couples.

  2. Sustancias naturales de moluscos opistobranquios: estudio de su estructura, origen y función en ecosistemas bentónicos

    OpenAIRE

    Ávila Escartín, Conxita

    1993-01-01

    Los Moluscos Opistobranquios, en relación a la reducción o incluso pérdida de la concha, han desarrollado múltiples y sofisticados métodos de defensa (incluyendo la defensa química) que les han permitido sobrevivir sin dicha defensa mecánica. En esta Tesis se estudia el papel de las sustancias naturales de Moluscos Opistobranquios, haciendo énfasis en aspectos biológicos tales como el origen dietético o biosintético de las mismas, su localización en el organismo, y su actividad y función en e...

  3. Bente Knoll, Elke Szalai: Frauenwege – Männerwege. Entwicklung von gendersensiblen Mobilitätserhebungen. Wien: Bundesministerium für Verkehr, Innovation und Technologie 2008.

    Directory of Open Access Journals (Sweden)

    Gabriele Sturm

    2009-11-01

    Full Text Available Der vorliegende Band ist typisch für Ressortforschung, bei der ein gesellschaftliches Interesse mit dem Handlungshorizont eines Ministeriums verknüpft wird. Über solch eine externe Beschränkung hinaus weist die Studie leider auch zahlreiche interne Einschränkungen infolge handwerklich schlecht eingesetzter Methoden oder unzureichender konzeptioneller Bezogenheit der verschiedenen Forschungsschritte auf. So überzeugt weder die transdisziplinäre Verknüpfung von Wissenschaft, Planung und Politik im Rahmenkonzept noch das interdisziplinäre Zusammenwirken der unterschiedlichen (Unter- Auftragnehmerinnen für den eigentlichen Forschungszweck – die Entwicklung und Prüfung eines gendersensiblen Mobilitätsfragebogens – und auch die Präsentation der Studie erfüllt nicht die Mindeststandards.The volume at hand is typical for strategic research in that it connects social interest to a governmental ministry’s sphere of action. Beyond such external limitations, the study unfortunately also displays multiple internal limitations due to poorly executed methods or inadequately conceived relationships between the various research steps. Because of this, the volume’s framing concept that includes transdisciplinary connections between science, planning, and politics remains inadequate. In addition, the interdisciplinary collaboration between the different (under agents for the volume’s stated research purpose – the development and testing of a gender-sensitive questionnaire on mobility – and the presentation of this study does not fulfill minimum standards.

  4. Udpegning af risikolokaliteter på det tosporede vejnet i åbent land baseret på data om vejens karakteristika

    DEFF Research Database (Denmark)

    Andersen, Camilla Sloth

    registreringsgraden er siden 2001 faldet fra, at 18,5 % af de tilskadekomne, der behandles på skadestue, også blev registreret i den officielle ulykkesstatstik, til at andelen, der blev registreret i 2011, er nede på 10 %. De danske vejmyndigheder, heraf særligt kommunerne, har derfor vanskeligt ved at udpege sorte...

  5. Assessment of the effect of No Stay, Bent Stay or Straight Stay when the Clothe the Soldier Rucksack is Worn with the Fragmentation Vest

    Science.gov (United States)

    2006-02-01

    Skin Contact Pressures An F-ScanTM pressure sensor system ( Tekscan Incorporated) was used to acquire contact pressure data on the manikin skin...pressure sensor system ( Tekscan Incorporated) was used to acquire contact pressure data on the mannikin skin over the anterior shoulder, posterior

  6. Study on the Pictures Code Bent Sorting Method of Chinese Newspaper%浅议中文报纸音画码排架排序法

    Institute of Scientific and Technical Information of China (English)

    郭科文

    2011-01-01

    This paper presents an arranging method for Chinese newspaper,with Pinyin and strokes combined.In accordance with the principle of "Pinyin-based,supplemented by stroke,Pinyin and strokes combined",to encode the newspaper based on the pinyin and stroke ord%本文提出一种以拼音与笔画相结合的中文报纸排架排序法。因其依照"拼音为主、笔画为辅,拼音与笔画相结合"的原则,根据报纸名称的拼音和笔画对报纸进行编码排序,故称为音画码排架排序法。此方法可灵活运用在开架报纸排架和闭架报纸库排架中,能给读者和图书馆工作人员带来极大的便利。

  7. Macroalgas bentónicas de los ríos de Castilla-La Mancha. Bases para el estudio de su potencial indicador

    OpenAIRE

    Monteagudo Canales, Laura

    2016-01-01

    Las especies indicadoras ofrecen, simplemente con su presencia, información acerca de las condiciones físicas y/o químicas del entorno que les rodea. Por tanto, la evaluación del potencial indicador de las macroalgas fluviales debe partir de una base sólida de conocimiento acerca de la diversidad de estos organismos y de cómo responden a las presiones antropogénicas que afectan a la calidad del agua. En Castilla-La Mancha, la mayoría de estudios sobre algas se han centrado en la cuenca de...

  8. Udpegning af risikolokaliteter på det tosporede vejnet i åbent land baseret på data om vejens karakteristika

    DEFF Research Database (Denmark)

    Andersen, Camilla Sloth

    I det stedbestemte trafiksikkerhedsarbejde har udpegning og udbedring af sorte pletter (identificering, analyse samt udbedring af risikolokaliteter på vejnettet) siden 1970’erne været en af de primære aktiviteter. Imidlertid er sortpletarbejdet med årene blevet vanskeligere af to grunde: Dels er ...

  9. Algebraic function operator expectation value based quantum eigenstate determination: A case of twisted or bent Hamiltonian, or, a spatially univariate quantum system on a curved space

    Energy Technology Data Exchange (ETDEWEB)

    Baykara, N. A. [Marmara University, Faculty of Sciences and Letters, Mathematics Department, Göztepe Campus, 34730, Istanbul (Turkey)

    2015-12-31

    Recent studies on quantum evolutionary problems in Demiralp’s group have arrived at a stage where the construction of an expectation value formula for a given algebraic function operator depending on only position operator becomes possible. It has also been shown that this formula turns into an algebraic recursion amongst some finite number of consecutive elements in a set of expectation values of an appropriately chosen basis set over the natural number powers of the position operator as long as the function under consideration and the system Hamiltonian are both autonomous. This recursion corresponds to a denumerable infinite number of algebraic equations whose solutions can or can not be obtained analytically. This idea is not completely original. There are many recursive relations amongst the expectation values of the natural number powers of position operator. However, those recursions may not be always efficient to get the system energy values and especially the eigenstate wavefunctions. The present approach is somehow improved and generalized form of those expansions. We focus on this issue for a specific system where the Hamiltonian is defined on the coordinate of a curved space instead of the Cartesian one.

  10. Practical Study on Single Bent Sliding Steerable BHA%单弯动力钻具滑动导向组合的实践研究

    Institute of Scientific and Technical Information of China (English)

    安克; 王敏生; 郗茂武; 奚国银; 胡贯平; 杨进

    2003-01-01

    导向钻进技术在特殊工艺井施工中的应用越来越广泛,对导向钻具组合复合钻进中的复合转速、井径及导向能力等几个问题进行了分析,结合单弯单稳导向组合在胜利油田2口分支水平井中的应用实践,对影响导向组合导向能力的因素和复合钻进中应注意的问题进行了分析.

  11. Comparative analysis of strength and crack resistance of normal sections of bent elements of T-sections, made of rubber concrete, kauton reinforcement and concrete

    Directory of Open Access Journals (Sweden)

    Potapov Yuriy

    2016-01-01

    Full Text Available One of the urgent tasks of development of the construction associated with the development of new building designs, the use of which provides increased strength, crack resistance, reducing the flow of construction materials, reducing the labor intensity, energy consumption and cost. Ensuring effective functioning of structures during their operation in the harsh environments associated not only with the task of developing materials of higher strength and corrosion resistance, but also composites of increased strength and crack resistance, as structural materials crack resistance is largely determined by the ability of the structure to prevent the formation and growth of cracks. For structures operating in conditions of chemical action, the question of crack resistance is paramount, as the disclosure of cracks in aggressive environment, penetrating deep into the section and causing corrosion of the reinforcement will significantly impair the ability of the load bearing capacity of the element as a whole. The results of experiments of polymer concrete beams of the cross T-profile and comparison of the results with those obtained in an experiment similar to concrete and kauton reinforced elements are given. The observations of the stress-strain state of polymer concrete of flexural members, strength and crack resistance of these elements are presented.

  12. Residual stress evaluation by X-Ray diffraction and hole-drilling in an API 5L X70 steel pipe bent by hot induction

    Energy Technology Data Exchange (ETDEWEB)

    Ceglias, Rodrigo Braga; Alves, Juciane Maria; Botelho, Ramon Alves; Baeta Junior, Eustaquio de Souza; Santos, Igor Cuzzuol dos; Moraes, Nicki Robbers Darciano Cajueiro de; Oliveira, Rebeca Vieira de; Diniz, Saulo Brinco; Brandao, Luiz Paulo, E-mail: brandao@ime.eb.br [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Secao de Engenharia Mecanica e de Materiais

    2016-09-15

    The API 5L X70 steel is used in high-pressure gas transmission pipelines. Because of this, knowledge of presence of residual stress and their magnitude is important to assess the material integrity in service. For the pipeline manufacturing, tubes need to be curved which is often made using the hot induction bending process. This process can introduce different residual stress depending of tube position. For this research, in order to evaluate the residual stress, was used an API 5L X70 tube that was previously curved by hot induction process. Samples were taken from the extrados, intrados, neutral line and straight section of the curved tube. Residual stresses were studied by two conventional methods: X-Ray Diffraction (XRD) and Hole-Drilling, which are destructive and non-destructive methods, respectively, in order to assess their qualitative responses. Each of these methods presents particular methodologies in sample preparation and material analysis, but also they differ in factors such time consumption and cost of the analysis. The qualitative responses obtained by the two different methods were comparable and satisfactory and pointed out the existence of a compressive residual stress state in steel pipe. (author)

  13. Study on Removal Method of Inclined Bents and Effect of Tuned Mass Damper of Long-span Cable-stayed Bridge(Megami Bridge)

    OpenAIRE

    北原, 雄一

    2009-01-01

    長大斜張橋の計画において架設工法を決定する場合,架設地点の地形状況,気候等の現地条件および使用可能な架設技術を基に,その橋梁に最も適した架設工法が決定される.さらに長大斜張橋では,主桁架設にバランシング工法が採用されることが多いので,架設時の耐風安定性の検討も不可欠となる.このように多くの検討すべき事項が架設工法に影響を与えるため,過去の長大斜張橋の架設に関する技術情報では不十分であり架設地点の状況に応じた検証が必要となる.  このため,本研究は,長崎県の長崎湾に架設された女神大橋を研究対象として架設地点に応じた斜ベントの撤去工法の実証と架設系,完成系における制振装置の効果検証を目的とする....

  14. Organic reactions for the electrochemical and photochemical production of chemical fuels from CO2--The reduction chemistry of carboxylic acids and derivatives as bent CO2 surrogates.

    Science.gov (United States)

    Luca, Oana R; Fenwick, Aidan Q

    2015-11-01

    The present review covers organic transformations involved in the reduction of CO2 to chemical fuels. In particular, we focus on reactions of CO2 with organic molecules to yield carboxylic acid derivatives as a first step in CO2 reduction reaction sequences. These biomimetic initial steps create opportunities for tandem electrochemical/chemical reductions. We draw parallels between long-standing knowledge of CO2 reactivity from organic chemistry, organocatalysis, surface science and electrocatalysis. We point out some possible non-faradaic chemical reactions that may contribute to product distributions in the production of solar fuels from CO2. These reactions may be accelerated by thermal effects such as resistive heating and illumination.

  15. Tafonomia de Foraminíferos Bentônicos em Sedimentos Siliciclásticos e Carbonáticos

    Directory of Open Access Journals (Sweden)

    Mariana Nunes Cardoso

    2007-07-01

    Full Text Available Biological, physical and chemical features work on the bioclasts, which react specifically under diverse environmental conditions. As consequence of the environment stress, the taphonomic signature onforaminiferal tests provides significant paleocological information. This study aims to compare taphonomic properties on foraminiferal tests from carbonate (lagoa Pitanguinha and siliciclastic (Reserva Tauá settings. On Reserva Tauá-Pântano da Malhada where identified 10 species and on lagoa Pitanguinha 9, that reveal low diversity. Hyaline and porcelaneous tests occur in carbonate deposits, while in the siliciclastic occurs only the hyaline one. The fragmentation was significant to both depositional environments, the dissolution wasfaintly higher on the siliciclastic and cyanobacterial microbioerosion was found exclusively on the carbonate. Ammonia tepida shows a high frequency, possessing great rates of bioerosion, fragmentation and dissolution.

  16. How to identify science being bent: the tobacco industry's fight to deny second-hand smoking health hazards as an example.

    Science.gov (United States)

    De Camargo, Kenneth Rochel

    2012-10-01

    Social studies of science have produced a critical description of science that challenges traditional ideas about "objectivity" and "neutrality". Given evidence that scientific tools have been used to undermine solid science against the interests of the general public as opposed to protecting society from findings prematurely declared to be facts, this article asks: how can one differentiate between the usual proceedings of scientists and deliberate attempts to distort science? In order to respond to this question, the author presents systematic studies of the distortion (or "bending") of science, with special attention to the role of public relation firms in the process. Drawing on examples from the tobacco industry, the article concludes that there are two key features of the tobacco industry case that indicate that distortions in science may have taken place: the fact that controversies surrounding tobacco has been centered in public forums, and legal or regulatory arenas more than scientific domains; and the presence of conflicts of interest in authorship and funding.

  17. Efecto de la contaminación hidrocarburífera sobre la estructura comunitaria de macroinvertebrados bentónicos presentes en el sedimento del Estero Salado

    OpenAIRE

    Cárdenas Calle, Maritza Cecilia

    2010-01-01

    El Estero Salado forma parte del Golfo de Guayaquil, se encuentra contaminado con hidrocarburos debido al aporte de aguas residuales industriales, derrames de petróleo, aguas de sentina, transferencia y transportación de combustibles, mal manejo de desechos sólidos. El objetivo de este estudio fue determinar el efecto de la contaminación hidrocarburíferas sobre la estructura comunitaria de macroinvertebrados presentes en el sedimento en el Estero Salado durante noviembre de 2009. Doce e...

  18. Infrared absorption spectroscopy of CO2-HX complexes using the CO2 asymmetric stretch chromophore: CO2HF(DF) and CO2HCl(DCl) linear and CO2HBr bent equilibrium geometries

    Science.gov (United States)

    Sharpe, S. W.; Zeng, Y. P.; Wittig, C.; Beaudet, R. A.

    1990-01-01

    Infrared absorption spectra associated with the CO2 asymmetric stretch vibration have been recorded for weakly bonded gas-phase complexes of CO2 with HF, DF, HCl, DCl, and HBr, using tunable diode laser spectroscopy and a pulsed slit expansion (0.15×38 mm2) that provides >20 MHz overall resolution. Results obtained with CO2-HF are in agreement with earlier studies, in which the HF-stretch region near 3900 cm-1 was examined. In both cases, broad linewidths suggest subnanosecond predissociation. With CO2-DF, the natural linewidths are markedly narrower than with CO2-HF (e.g., 28 vs 182 MHz), and this difference is attributed to slower predissociation, possibly implicating resonances in the case of CO2-HF. Both CO2-HF and CO2-DF exhibited overlapping features: simple P and R branches associated with a linear rotor, and P and R branches containing doublets. As in earlier studies, the second feature can be assigned to either a slightly asymmetric rotor with Ka=1, or a hot band involving a low-frequency intermolecular bend mode. Results obtained with CO2-HCl are in excellent agreement with earlier microwave measurements on the ground vibrational state, and the vibrationally excited state is almost identical to the lower state. Like CO2-DF, linewidths of CO2-HCl and CO2-DCl are much sharper than those of CO2-HF, and in addition, CO2-HCl and CO2-DCl exhibited weak hot bands, as were also evident with CO2-HF and CO2-DF. Upon forming complexes with either HF or HCl, the asymmetric stretch mode of CO2 underwent a blue shift relative to uncomplexed CO2. This can be understood in terms of the nature of the hydrogen bonds, and ab initio calculations are surprisingly good at predicting these shifts. Deuteration of both HF and HCl resulted in further blue shifts of the band origins. These additional shifts are attributed to stronger intermolecular interactions, i.e., deuteration lowers the zero-point energy, and in a highly anharmonic field this results in a more compact average structure. While both HF and HCl complexes exhibit nearly linear geometries,CO2-HBr is asymmetric, with the Br-C symmetry line essentially perpendicular to the CO2 axis, and the H atom probably localized near one of the oxygens. Although the moments of inertia are insensitive to the location of the H atom in CO2-HBr, Bose-Einstein statistics require that odd K`a states are missing for C2v symmetry, as is observed with T-shaped CO2-(rare gas) complexes. However, we observe a full complement of odd and even Ka states, indicating that the H atom is not located symmetrically about the C2v axis on the time scale of the measurement. With CO2-HBr, the low gas-phase acidity of HBr and the high Br-atom polarizability encourage a qualitative change in the geometry relative to CO2-HCl and CO2-HF. This has valuable implications for photoinitiated reactions in such complexes.

  19. Estrutura da comunidade de invertebrados bentônicos em dois cursos d'água do Rio Grande do Sul, Brasil Community structure of benthic invertebrates in two watercourses in Rio Grande do Sul State, southern Brazil

    Directory of Open Access Journals (Sweden)

    Alessandra A. P. Bueno

    2003-03-01

    Full Text Available The benthic fauna has an important role in the trophic chain of limnic environments, serving as food for fishes and crustaceans. This work aimed to identify and compare, quantitative and qualitatively, the macrobenthic communities from two watercourses in Rio Grande do Sul State. Samplings were done with a Surber sampler, monthly, from September 1999 to August 2000, in one of the creeks forming Tainhas River(29º15'30,2"S, 50º13'12,5"W, around São Francisco de Paula city and in Mineiro Creek (29º30'0,2"S, 50º46'50"W, around Taquara city. At each sampling point, physical and chemical variables of the waters were registered. In the laboratory, the samples were sorted out and the animals identified and quantified. Dissolved oxigen, pH and stream speed were very similar for both environments, whilst conductivity had extreme values. Insects, crustaceans, acari and molluscs dominated in the samples. Abundance, richness and diversity indexes in Tainhas subsidiary had relatively higher average values than Mineiro Creek. Similarity matrix groupings between sampling units indicate three groups. Our research revealed important characteristics of the ecology and distribution of benthic invertebrates, information that can subsidise future environmental monitoring in the region of São Francisco de Paula and Taquara.

  20. Solid-state 13C NMR study of banana liquid crystals - 3: Alkyl-tail-group packing environments of an acute-angle bent-core molecule in the hexagonal columnar and cubic phases

    Science.gov (United States)

    Kurosu, Hiromichi; Endo, Yumi; Kimura, Saori; Hashimoto, Tomoko; Harada, Motoi; Lee, Eun-Woo; Sone, Masato; Watanabe, Junji; Kang, Sungmin

    2016-02-01

    Solid-state 13C nuclear magnetic resonance (NMR) measurements were performed on the hexagonal columnar and cubic phases of an acute-angle banana-shaped molecule, N(1,7)-S30. In the hexagonal columnar phase, three peaks appear at the NMR chemical shifts assigned to the internal methylene carbons of alkyl tails, indicating that the two alkyl tails have different packing structures, and one of the tails has two different conformations within a single molecule. Combined cross-polarization/magic-angle spinning and pulse saturation transfer/magic-angle spinning measurements show that one of the alkyl chains is located inside and the other is located outside the columnar structure. In the cubic phase, pulse saturation transfer/magic-angle spinning measurement shows that only one peak appears at the NMR chemical shifts assigned to the internal methylene carbons of alkyl tails, indicating that both of the alkyl chains are located outside the cubic structure.

  1. Estudio de la biología trófica de cinco especies de peces bentónicos de la costa de Cullera. Relaciones con la acumulación de metales pesados

    OpenAIRE

    JARAMILLO LONDOÑO, ÁNGELA MARÍA

    2011-01-01

    Los estudios acerca de la ecología trófica de los peces, en los cuales se relacionan la biología y fisiología de las especies con su hábitat, régimen alimentario, tipo de dieta y relaciones bióticas, aportan información básica y necesaria para comprender el papel ecológico que desempeñan estos organismos dentro del ecosistema que habitan, y por lo tanto para establecer protocolos de gestión de sus poblaciones. Esta tesis aporta un mayor conocimiento de la biología, fenología y hábitos alim...

  2. Utilización potencial del control de las comunidades bentónicas intermareales como indicador de la alteración ambiental: Troia Resort (Portugal), un proyecto turístico de gran escala, como caso de estudio

    OpenAIRE

    FERREIRA, M. de A.; Arias-Andrade, F. (Francisco)

    2003-01-01

    Sandy beaches are the key attraction in coastal tourist projects, and are directly affected by such uses as construction of infrastructure and recreation. Benthic communities integrate, in space and time, the variability of the environment they occupy, and constitute useful indicators of the environmental change induced by projects built on the shoreline. Their study can, therefore, assist decision-makers in the management of these sensitive areas. In the framework of the environmental asses...

  3. Efeitos da VariaÃÃo Sazonal de um banco de Halodule wrightii Ascherson sobre comunidades bentÃnicas associadas, na Praia das Goiabeiras, Fortaleza-CE

    OpenAIRE

    kcrishna Vilanova de Souza Barros

    2008-01-01

    No Brasil, o grau de variaÃÃo de caracteres morfolÃgicos especÃficos de Halodule wrightii tem sido raramente reportado na literatura, dificultando a comparaÃÃo entre bancos de diferentes Ãreas. Estudos sobre assemblÃias faunÃsticas associadas tambÃm sÃo considerados raros, sobretudo, com relaÃÃo Ãs interaÃÃes planta-animal. Fatores ambientais podem influenciar fortemente a morfologia das plantas, mas existem poucos estudos ambientais que demonstram esse fato para a espÃcie H. wrightii. No est...

  4. Comparative study of the estimated sample size for benthic intertidal species and communities Estudio comparativo del tamaño estimativo de muestra para especies bentónicas intermareales y de la comunidad

    Directory of Open Access Journals (Sweden)

    Danielle C Barbiero

    2011-01-01

    Full Text Available The objective of this study was to determine the minimum sample size for studies of community structure and/or dominant species at different heights of a rocky intertidal zone at Rio de Janeiro. Community structure indicators suggested a variation in the minimum surface of 100 to 800 cm , with a minimum of 2 to 8 pro files and at least 20 to 80 quadrant sampling points, depending on the height. Indicators of species abundance suggest 100 cm for Hypnea musciformis and 400 cm for Ulva fasciata, Phragmatopoma lapidosa Kinberg, (1867 and Gymnogongrus griffthsiae at lower heights; 200 cm² for Chthamalus spp. at intermedíate heights; and 800 cm for Littorina ziczac at the greatest height. In general, seven to eight profiles and 10 to 20 sampling points were used. Different sample sizes were related to the abundance and spatial distributions of individual species, which varied at each intertidal height according to the degree of environmental stress.El objetivo de este estudio fue determinar el tamaño mínimo de muestra para estudios de estructura de la comunidad y para las especies dominantes a diferentes alturas, en una zona intermareal rocosa en Río de Janeiro. Los indicadores de la estructura de la comunidad sugirieron una variación en la superficie mínima de 100 a 800 cm , 2 a 8 el número mínimo de perfiles y 20 a 80 el número mínimo de puntos de muestreo de cuadrantes, dependiendo en la altura. Los indicadores de abundancia de especies sugieren 100 cm para Hypnea musciformis, 400 cm para Ulva fasciata, Phragmatopoma lapidosa Kinberg, (1867 y Gymnogongrus griffthsiae a las alturas inferiores; 200 cm² para Chthamalus spp. a las alturas mediales y 800 cm para Littorina ziczac a la altura superior. El número de perfiles y puntos de muestreo fue, en general, 7-8 y 10-20, respectivamente. Diferentes tamaños de la muestra fueron relacionados con la abundancia de especies individuales y su distribución espacial, que varían en cada altura de la zona intermareal de acuerdo con el grado de stress ambiental.

  5. Asociaciones de foraminíferos bentónicos cuaternarios de la plataforma del río Maroni (Guayana francesa): contribución paleogeográfica

    OpenAIRE

    Pascual, Ana; Pujos, Michel

    1997-01-01

    The distribution of benthic foraminiferal microfauna recovered from two cores on the Maroni continental shelf (French Guiana) has been studied. 1 00 species and two types of foraminiferal assemblages have been identified in the study area. They characterize a record of oceanographic changes from lateQuaternary (3000 years B.P) to the present The assemblage of unit 2 indicates a shelf environment with strong erosion (deeper core KS 33), also an old lagoon with temporary anoxy events (shallower...

  6. The Knight and the King: two new species of giant bent-toed gecko (Cyrtodactylus, Gekkonidae, Squamata) from northern New Guinea, with comments on endemism in the North Papuan Mountains

    Science.gov (United States)

    Oliver, Paul M.; Richards, Stephen J.; Mumpuni; Rösler, Herbert

    2016-01-01

    Abstract The diverse biota of New Guinea includes many nominally widespread species that actually comprise multiple deeply divergent lineages with more localised histories of evolution. Here we investigate the systematics of the very large geckos of the Cyrtodactylus novaeguineae complex using molecular and morphological data. These data reveal two widespread and divergent lineages that can be distinguished from each other, and from type material of Cyrtodactylus novaeguineae, by aspects of size, build, coloration and male scalation. On the basis of these differences we describe two new species. Both have wide distributions that overlap extensively in the foothill forests of the North Papuan Mountains, however one is seemingly restricted to hill and lower montane forests on the ranges themselves, while the other is more widespread throughout the surrounding lowlands. The taxon endemic to the North Papuan Mountains is related to an apparently lowland form currently known only from Waigeo and Batanta Island far to the west – hinting at a history on island arcs that accreted to form the North Papuan Mountains. PMID:27006624

  7. 丘陵地区长输管道带弯管下沟技术研究%Study on Lowering Long-distance Pipeline with Bent Pipes into Trench

    Institute of Scientific and Technical Information of China (English)

    郑明高

    2010-01-01

    巴西GASCAV天然气管道工程,由于地形起伏,管道的弯管用量大,施工采用沟上组焊带弯管下沟方式,因此根据地形确定管沟弯点、进行管沟开挖和管道下沟难度大.文章对弯管下沟的几种工况(水平弯、纵向弯和迭加弯)进行了理论分析,提出了通过调整弯点位置、适当加大开挖量、控制施工工序等措施来解决工程难题,并成功地实施.

  8. 弯壳体导向钻具造斜能力影响因素分析%The Influential Factors Analyses of Bent Housing Steerable-Motor's Build Angle Capability

    Institute of Scientific and Technical Information of China (English)

    闫铁; 王辉; 毕雪亮

    2010-01-01

    下部钻具组合尤其导向钻具的造斜能力不但是评价工具性能的主要指标,也是井眼轨迹控制的重要依据,并且准确地设计和预测下部钻具组合的造斜能力更是实现连续导向钻井的技术关键,因此分析弯壳体导向钻具造斜能力的影响因素具有十分重要的意义.从研究导向钻具组合造斜能力的影响因素出发,应用三点定圆法预测造斜能力,重点分析影响因素对不同导向钻具造斜能力的影响,并绘制出各种影响曲线图,直观地反映出造斜能力随影响因素的变化.

  9. The Bent Branches---Chinese Online Literature Viewed from Nationalist Angle%“压弯的树枝”--民族主义视野下的中国网络文学

    Institute of Scientific and Technical Information of China (English)

    胡疆锋

    2014-01-01

    In the process of much mentioned historical context and globalization, Chinese online literature nurtures a complicated and rich mindset of a powerful nation, concerning Chinese territory, national sovereignty, national dignity, cultural identity, foreign policy, and other heated topics, which results in the cause-and-effect relationship with the new nationalism. Online literature reveals the difficult problems in Chinese society and tries to solve them, and clearly depicts the Chinese youth's search for their identity with complicated national consciousness, rational, feverish, nihilistic, cynical, and so on. The negative and harmful trends of contemporary nationalism manifested in online literature should be pointed out and discarded.%在架空的历史语境和全球化境遇中,中国网络文学建构出了复杂而丰富的大国想象,涉及中国领土、国家地位、民族尊严、文化认同、外交政策等热点问题,与新一轮的民族主义形成了互为因果的关系。网络文学揭示出并试图“解决”中国社会中许多尚未解决的难题,清晰勾勒出了当代中国青年在理性、狂热、虚无、犬儒等复杂的民族意识中寻找认同之路的印迹。网络文学中所体现出的当代民族主义中的一些不良倾向应该引起警惕并加以摒弃。

  10. Method Comparison Study for Bent Type Hopper Knuckle of CSR-BC Structural Fatigue Assessment%散货船弯曲型底边舱折角疲劳评估方法对比研究

    Institute of Scientific and Technical Information of China (English)

    袁鸿宇

    2015-01-01

    主要结合散货船共同结构规范及劳氏船级社规范,对一艘64 000 dwt散货船其弯曲型底边舱折角区域内的结构采用简单计算法及谱分析法进行疲劳分析,并对其计算结果差异进行对比研究.

  11. Análise Multivariada de Dados Ecológicos da Baía de Guanabara- RJ,com Base em Foraminíferos Bentônicos.

    Directory of Open Access Journals (Sweden)

    Priscila Tavares dos Santos

    2007-07-01

    Full Text Available Guanabara bay is an estuary environment situated in the seaboard of Rio de Janeiro state, under the coordinates 22º 40’ and 23º 00’S and 43º 00’ and 43º 20’W. Nowadays, it has an approximate area of 377 km2, it has had a reduction of 91 km2 since the discovery of Brazil, being considered one of the most polluted seacoast regions of the country. The environmental monitoring of Guanabara bay becomes increasingly necessary in order to be capable of taking effectivemeasures in its management. Therefore, the use of bioindicator organisms, like foraminifera, is an excellent tool because of their rapid response to environmental changes. The goal of this paper is to apply statistical analyses to the biotic data benthicforaminifera, aiming to observe how they behave in Guanabara bay. In November 1999, samples of bottom sediment were collected along Guanabara bay; 52 of them distributed along all the bay were used in this study. They were treated and classified according to the pattern methodology for foraminifera. For the numerical ecology, grouping analysis and indicating species analysis (ISA were done using the programs Statistica 6.0 and PCORD. Through the groupinganalysis, it was observed the formation of groups in both samples and species. ISA showed what species is the best one toindicate the actual state of Guanabara bay - Ammonia tepida. The multivaried ecological analyses had an optimal response in the evaluation of patterns of pollution in Guanabara bay, based on benthic foraminifera.

  12. 可控弯接头变异万向轴和轴承的强度模拟分析%Strength Simulation Analysis of the Variation Cardan Shaft and Bearing on Controllable Bent Sub

    Institute of Scientific and Technical Information of China (English)

    张光伟; 李钊; 游莉

    2014-01-01

    为了促进我国旋转导向钻井技术发展,对智能型井下闭环旋转导向工具——可控弯接头的结构和工作原理进行了介绍,并用ANSYS软件对旋转导向钻井工具中的变异万向轴和推力轴承进行了研究,分析了推力轴承、滚子和变异万向轴的相互作用及应力分布情况.分析结果表明,接触配合中危险区域的最大应力为234 MPa,发生在轴承上与滚子接触的球窝边缘部分,与赫兹理论相符;变异万向轴和推力轴承都能较好地满足强度要求.

  13. A novel approach for removing 2-naphthol from wastewater using immobilized organo-bentonite.

    Science.gov (United States)

    Sun, Xiaohui; Huang, Wenfei; Ma, Zhanyu; Lu, Yingying; Shen, Xueyou

    2013-05-15

    The major concern limiting the industrial application of organo-bentonite in powder form (P-Bent) for wastewater treatment is that it is difficult to separate it from treated water by settlement. To address this problem, a novel approach for synthesizing immobilized organo-bentonite in globular form (G-Bent) is proposed. The G-Bent is modified using the cationic surfactant cetylpyridinium chloride (CPC) and immobilized by polyvinyl alcohol (PVA). The removal of 2-naphthol by G-Bent was compared with removal by P-Bent for solid/liquid separation, removal efficiency and desorption of the modifier used in its preparation. Results indicated that G-Bent was easy to recover from treated wastewater, and was effective and reusable in removing 2-naphthol. The percentage of 2-naphthol removed by G-Bent exceeded 90% with the cationic exchange capacity (CEC) loadings ranging from 100% to 150%. This was almost equivalent to the results obtained using P-Bent. In the five rounds of reuse examined, the percentage of 2-naphthol removed was maintained above 50% for 150%-G-Bent. The percentage of CPC desorption was less than 0.75% after five rounds of reuse and no PVA was detected. The results of this work provide novel information for using G-Bent in the treatment of wastewater containing organic contaminants.

  14. Crystals channel high-energy beams in the LHC

    CERN Multimedia

    CERN Bulletin

    2015-01-01

    Bent crystals can be used to deflect particle beams, as suggested by E. Tsyganov in 1976. Experimental demonstrations have been carried out for four decades in various laboratories worldwide. In recent tests, a bent crystal inserted into the LHC beam halo successfully channelled and deflected 6.5 TeV protons into an absorber, with reduced secondary irradiation.    Quasimosaic crystal for the LHC (developed by PNPI). Bent crystal technology was introduced at CERN and further developed for the LHC by the UA9 Collaboration. For about ten years, experts from CERN, INFN (Italy), Imperial College (UK), LAL (France), and PNPI, IHEP and JINR (Russia) have been investigating the advantages of using bent crystals in the collimation systems of high-energy hadron colliders. A bent crystal replacing the primary collimator can deflect the incoming halo deeply inside the secondary collimators, improving their absorption efficiency. “The bent crystals we have just tested at the world-record en...

  15. 大连国际会议中心超长空间弯扭外围护钢柱安装技术%INSTALLATION TECHNIQUE FOR SUPER-LONG SPACE BENT AND TWISTED EXTERNAL ENCLOSURE STEEL COLUMN OF DALIAN INTERNATIONAL CONFERENCE CENTER PROJECT

    Institute of Scientific and Technical Information of China (English)

    周光毅; 王磊; 唐家如; 毛立贤; 陈超

    2013-01-01

    大连国际会议中心工程弯扭外围护钢柱结构工程量大,施工难度大.在采用SAP2000等软件进行施工过程模拟的基础上,有针对性地实施了复杂空间钢结构的安装施工,施工质量满足规范及设计要求,为后续外装饰工程施工创造了条件.

  16. 碗扣式与钢管扣件式超重平台结构排架支撑体系的对比%Comparison of Bowl-Type and Steel Pipe Type Fastener Bent Support System for Super Heavy Platform Structure

    Institute of Scientific and Technical Information of China (English)

    胡昊

    2012-01-01

    碗扣式排架支撑体系与钢管扣件式脚手支撑体系是目前比较常用的排架支撑体系。以某地下综合体工程的超重混凝土结构支撑体系施工为例,评论这两种排架支撑体系在该类工程中的优劣,可供类似工程参考。

  17. Diversity, dynamics and biogeography of Chilean benthic nearshore ecosystems: an overview and guidelines for conservation Diversidad, dinámica y biogeografía del ecosistema costero bentónico de Chile: revisión y bases para conservación marina

    Directory of Open Access Journals (Sweden)

    MIRIAM FERNANDEZ

    2000-12-01

    Full Text Available Despite Chile has been one of the pioneering countries in studies of human impact on marine communities, and despite the enormous economic and social significance that the marine environment has for the country, the development of marine conservation programs and the scientific basis for sustainability has not kept pace, with the exploitation rate of marine fisheries and the increasing use of the coast for other purposes. Although we think that the establishment of any conservation policies along the vast coastline of Chile must be based on a multitude of approaches and considerations, scientific, biological, and ecological principles should guide much of these efforts. In this paper, we attempt to present a general overview of the current knowledge about the ecology and biogeography of nearshore systems in Chile. Based on the most relevant existing information, our goals are to: 1 Identify major biogeographic and ecological features of nearshore ecosystems, and the obvious gaps in information, 2 identify the most harmful human activities impacting the structure and dynamics of these systems, and 3 suggest the possible use of indicators to assess the conservational status of different environments along the coast. This overview shows, on one side, the geographic areas of deficitary knowledge on nearshore environments that are critical for future marine conservation and management plans, and on the other, the availability of high quality information for other geographic areas along the coast. Regarding the taxonomy and large-scale patterns of species distribution, important gaps in information were detected, however no big changes in the total number of species are expected in the future. There are few large-scale patterns of species distribution are reported in the literature, and in this contribution, but more work needs to be done, particularly for some taxa, to identify areas of high species diversity as well as areas which possess unique characteristics in terms of ecosystem processes (e.g., particular disturbance and upwelling regimes in coastal marine ecosystems and species (e.g., endemic and keystone species. For most marine invertebrates and macroalgae, hotspots in species diversity are present in southern Chile. New studies addressing the causal factors generating these large-scale patterns of species distribution are also needed; information about coastal oceanography and larval supply is still poor. This information crucial for the design of a marine reserve network. The information available on community structure and ecosystem functioning, especially highlighting the effect of human impact, comes from very few geographic regions. More information about community structure for other areas of the coast is required, particularly considering the strong differences in temperature, circulation patterns, habitat heterogeneity, species composition, as well as of upwelling and El Niño effects along the 4,000 km of coastline. Finally, we list what we think are the most harmful human activities by area and environment along the coast, and integrate this information to suggest possible environmental indicators, and basic needs and guidelines for marine conservation in ChileA pesar de que Chile ha sido un país pionero en estudios del efecto del impacto humano sobre la estructura comunitaria en ambientes marinos, y a pesar de la enorme importancia económica y social que el ambiente marino tiene para el país, el desarrollo de programas de conservación marina y de bases científicas para la sustentabilidad no se han generado a la misma tasa a la que han explotado los recursos y se ha utilizado el ambiente costero para diversos fines. Aunque nosotros pensamos que el establecimiento de planes de conservación a lo largo de la costa de Chile debe basarse en varios factores, los principios científicos, biológicos y ecológicos deben guiar muchos de estos esfuerzos, y en este trabajo nosotros intentamos presentar una visión general del estado actual del conocimiento sobre la ecología y la biogegrafía del sistema costero en Chile. En base a la información más relevante existente, nuestros objetivos son: 1 identificar las características biogeográficas y ecológicas del ecosistema costero y también vacíos en información, 2 identificar las actividades humanas más dañinas que tengan impacto en la estructura y dinámica de estos sistemas, y 3 sugerir el uso de posibles indicadores para determinar la situación de diferentes áreas de la costa de Chile, y las necesidades de conservación. Esta revisión muestra, por un lado, áreas geográficas con información crítica deficitaria para planes futuros de manejo y conservación marina , y por el otro lado, la disponibilidad de información de alta calidad para otras zonas geográficas del país. Respecto de la información existente sobre taxonomía y patrones de distribución de especies a gran escala, existen importantes vacíos de información; no se esperan en el futuro grandes cambios en el número total de especies. Existen pocos estudios sobre patrones de distribución de especies a gran escala, y más información es necesaria para identificar áreas de alta diversidad de especies, especialmente para algunos taxa, como también para identificar áreas que posean características únicas en relación a especies (endémicas, especies claves y a procesos ecosistémicos (disturbios, surgencias. Para la mayoría de los invertebrados y macroalgas, las áreas de alta diversidad de especies se encuentran en el sur de Chile. Nuevos estudios dirigidos a entender los factores que podrían generar patrones a macroescala son necesarios, como también información sobre oceanografía costera y disponibilidad de larvas. Esta información es clave para el diseño de una futura red de parques marinos. Por otro lado, la información disponible sobre estructuras comunitarias y funcionamiento ecosistémico, especialmente sobre el efecto del impacto humano, provienen de pocas regiones geográficas. Mas información sobre otras zonas geográficas es requerida, particularmente si se consideran las diferencias notables en temperatura, patrones de circulación, heterogeneidad del habitat, y composición de especies, como también el efecto de surgencia y de El Niño a lo largo de los más de 4.000 km de costa de Chile. Finalmente, listamos las que consideramos son las actividades humanas más dañinas para el ambiente marino, e integramos esta información para sugerir posibles indicadores ambientales y necesidades básicas y sugerencias para conservación marina in Chile

  18. Biología, distribución e integración del alga alóctona Undaria pinnatifida (Laminariales, Phaeophyta en las comunidades bentónicas de las costas de Galicia (NW de la Península Ibérica

    Directory of Open Access Journals (Sweden)

    Cremades Ugarte, Javier

    2006-12-01

    Full Text Available Undaria pinnatifida is an Asian seaweed that is valuable as an edible species. This kelp was first reported for Spain in the 1980s on Galician coasts, where it is now widely distributed and incorporated into the native community. In Galicia, intertidal populations of the sporophytic phase typically inhabit sites under moderate wave-exposure in the early spring, albeit they can be found throughout the year as the species displays at least two recruitment periods per year. The morphology varies between individuals and depends strongly on the spatiotemporal pattern of environmental conditions. The chronology of the introduction of this species and the types of habitat where it is currently integrated on Galician coasts clearly reveal that the presence and local expansion of this kelp is influenced largely by human activities, mainly shellfish aquaculture and maritime traffic. U. pinnatifida has a slow natural expansion, limited aggressiveness and it temporarily fills empty niches; this kelp displays luxuriant growth only on artificial substrates or in otherwise disturbed communities.Undaria pinnatifida es una especie asiática de gran interés económico como alga alimentaria que en la década de los ochenta apareció por primera vez en España en las costas de Galicia, donde actualmente se encuentra ampliamente distribuida y naturalizada. Las poblaciones intermareales de los esporófitos de esta especie en la costa gallega son propias de localidades moderadamente expuestas a la acción del oleaje, siendo muy notorias a principios de primavera; aunque pueden encontrarse casi todoel año, al existir al menos dos períodos anuales de reclutamiento. La morfología de los ejemplares que las forman es muy variable y está fuertemente relacionada con las variaciones espaciotemporales de las condiciones ambientales. Analizando la cronología de su introducción en Galicia y los hábitats y tipos de comunidades en las que se integra, se observa claramente la influencia de las actividades humanas en todo ello, sobre todo las derivadas de la acuicultura de moluscos y el tráfico marítimo. U. pinnatifida es una especie de lenta expansión natural, poco agresiva y que ocupa temporalmente nichos ecológicos vacíos, siendo solo abundante sobre sustratos artificiales o en aquellos naturales cuya vegetación ha sido en alguna medida previamente degradada.

  19. Full dimensional Franck-Condon factors for the acetylene tilde{{A}} 1Au—{tilde{X}} {^1Σ _g^+} transition. I. Method for calculating polyatomic linear—bent vibrational intensity factors and evaluation of calculated intensities for the gerade vibrational modes in acetylene

    Science.gov (United States)

    Park, G. Barratt

    2014-10-01

    Franck-Condon vibrational overlap integrals for the tilde{A} {^1A_u}—{tilde{X}} {^1Σ _g^+} transition in acetylene have been calculated in full dimension in the harmonic normal mode basis. The calculation uses the method of generating functions first developed for polyatomic Franck-Condon factors by Sharp and Rosenstock [J. Chem. Phys. 41(11), 3453-3463 (1964)], and previously applied to acetylene by Watson [J. Mol. Spectrosc. 207(2), 276-284 (2001)] in a reduced-dimension calculation. Because the transition involves a large change in the equilibrium geometry of the electronic states, two different types of corrections to the coordinate transformation are considered to first order: corrections for axis-switching between the Cartesian molecular frames and corrections for the curvilinear nature of the normal modes at large amplitude. The angular factor in the wavefunction for the out-of-plane component of the trans bending mode, ν _4^' ' }, is treated as a rotation, which results in an Eckart constraint on the polar coordinates of the bending modes. To simplify the calculation, the other degenerate bending mode, ν _5^' ' }, is integrated in the Cartesian basis and later transformed to the constrained polar coordinate basis, restoring the conventional v and l quantum numbers. An updated tilde{A}-state harmonic force field obtained recently in the R. W. Field research group is evaluated. The results for transitions involving the gerade vibrational modes are in qualitative agreement with experiment. Calculated results for transitions involving ungerade modes are presented in Paper II of this series [G. B. Park, J. H. Baraban, and R. W. Field, "Full dimensional Franck-Condon factors for the acetylene tilde{A} {^1A_u}—{tilde{X}} {^1Σ _g^+} transition. II. Vibrational overlap factors for levels involving excitation in ungerade modes," J. Chem. Phys. 141, 134305 (2014)].

  20. Full dimensional Franck-Condon factors for the acetylene à (1)A(u)-X̃ (1)Σ(g)(+) transition. I. Method for calculating polyatomic linear-bent vibrational intensity factors and evaluation of calculated intensities for the gerade vibrational modes in acetylene.

    Science.gov (United States)

    Park, G Barratt

    2014-10-07

    Franck-Condon vibrational overlap integrals for the à Au1-X̃ 1Σg+ transition in acetylene have been calculated in full dimension in the harmonic normal mode basis. The calculation uses the method of generating functions first developed for polyatomic Franck-Condon factors by Sharp and Rosenstock [J. Chem. Phys. 41(11), 3453-3463 (1964)], and previously applied to acetylene by Watson [J. Mol. Spectrosc. 207(2), 276-284 (2001)] in a reduced-dimension calculation. Because the transition involves a large change in the equilibrium geometry of the electronic states, two different types of corrections to the coordinate transformation are considered to first order: corrections for axis-switching between the Cartesian molecular frames and corrections for the curvilinear nature of the normal modes at large amplitude. The angular factor in the wavefunction for the out-of-plane component of the trans bending mode, ν4(″), is treated as a rotation, which results in an Eckart constraint on the polar coordinates of the bending modes. To simplify the calculation, the other degenerate bending mode, ν5(″), is integrated in the Cartesian basis and later transformed to the constrained polar coordinate basis, restoring the conventional v and l quantum numbers. An updated Ã-state harmonic force field obtained recently in the R. W. Field research group is evaluated. The results for transitions involving the gerade vibrational modes are in qualitative agreement with experiment. Calculated results for transitions involving ungerade modes are presented in Paper II of this series [G. B. Park, J. H. Baraban, and R. W. Field, "Full dimensional Franck-Condon factors for the acetylene à Au1-X̃ 1Σg+ transition. II. Vibrational overlap factors for levels involving excitation in ungerade modes," J. Chem. Phys. 141, 134305 (2014)].

  1. Distribución de foraminíferos bentónicos (Protozoa: Foraminiferida en la ensenada Quillaipe (41°32' S; 72°44' O, Chile: Implicaciones para el estudio del nivel del mar Distribution of benthic foraminifera (Protozoa: Foraminiferida in the Quillaipe Inlet (41°32' S; 72°44' W, Chile: Implications for sea level studies

    Directory of Open Access Journals (Sweden)

    LEONARDO D FERNÁNDEZ

    2010-12-01

    Full Text Available Los foraminíferos de las marismas salobres son utilizados como indicadores del cambio producido en el nivel del mar durante el Holoceno. No obstante, los foraminíferos de las marismas de Chile han sido escasamente estudiados por lo que se desconoce la factibilidad de utilizarlos para este fin. Para subsanar esto se desarrolló una investigación en el intermareal de la ensenada de Quillaipe, Chile, con los objetivos de determinar los foraminíferos y su distribución vertical; analizar los parámetros que explican su distribución y determinar las especies que son útiles como indicadoras del nivel del mar. Los resultados revelaron 18 especies (nueve aglutinadas y nueve calcáreas distribuidas en dos grandes Zonas (I y II. La Zona I se restringió a la parte más alta y vegetada del intermareal (marisma y estuvo habitada solo por taxa aglutinados. Aquí se registraron bajos valores de diversidad (H' = 0.567, pH (6.6 y salinidad (18.7 y un dominio de la especie aglutinada Haplophragmoides manilaensis. En cambio, la Zona II se limitó a la zona menos elevada y sin vegetación del intermareal (llanura de marea y estuvo habitada por una comunidad calcárea-aglutinada. Contrariamente, los valores de diversidad (H' = 0.909, pH (7.7 y salinidad (32.8 fueron más altos, y la especie dominante fue la calcárea Ammonia beccarii. Por otro lado, la asociación aglutinada Trochamminita salsa-Jadammina macrescens se restringió a la parte más alta de la marisma y a los valores más bajos de salinidad y pH. Estos antecedentes permiten concluir que la distribución de los foraminíferos está controlada por la salinidad, el pH y la elevación del intermareal y que la asociación Trochamminita salsa-Jadammina macrescens son indicadoras del máximo nivel del mar en la ensenada de Quillaipe.Saltmarsh foraminifera are used as indicators of sea-level change which occurs during the Holocene. In Chile however, the saltmarsh foraminifera have been poorly studied, so it is unknown the feasibility of using them for this purpose. To address this issue, a research was conducted in the intertidal Quillaipe Inlet, Chile, in order to determine the vertical distribution of foraminifera and to analyze the parameters that explain their distribution and determine the species that are useful as indicators of sea level. The results revealed 18 species (nine calcareous and nine agglutinated distributed in two zones (I and II. Zone I was restricted to the saltmarsh and inhabited exclusively by agglutinated community. Here, diversity (H' = 0.567, pH (6.6 and salinity (18.7 values were low with a dominance of agglutinated species Haplophragmoides manilaensis. Zone II was restricted to tidal fíat and inhabited by a calcareous-agglutinated community. In contrast, diversity (H' = 0.909, pH (7.7 and salinity (32.8 values were higher, and the dominant species was the calcareous Ammonia beccarii. On the other hand, the agglutinated association Trochamminita salsa-Jadammina macrescens was restricted to the top of the saltmarsh and to low salinity and pH values. We conclude that the distribution of foraminifera is controlled by salinity, pH and the elevation of intertidal área and suggest that Trochamminita salsa-Jadammina macrescens association could be used as indicators of the maximum sea-level in the Quillaipe Inlet.

  2. Seasonal variability on the structure of sublittoral macrozoobenthic association in the Patos Lagoon estuary, southern Brazil Variabilidade sazonal na estrutura da associação de macroinvertebrados bentônicos em uma enseada estuarina da Lagoa dos Patos, sul do Brasil

    Directory of Open Access Journals (Sweden)

    Leonir A. Colling

    Full Text Available The aim of this study is to analyze and relate the spatial-temporal variability of macrozoobenthic assemblages to bottom characteristics and salinity fluctuations, in an estuarine shallow water region of Patos Lagoon. Monthly samples, between September 2002 and August 2003, were taken on six sampling stations (distant 90 m. Three biological samples with a 10 cm diameter corer, one sample for sediment analysis, fortnightly bottom topography measurements, and daily data of temperature and salinity were taken from each station. Two biotic and environmental conditions were identified: the first corresponding to spring and summer months, with low macrozoobenthos densities, low values of salinity, small variations in bottom topographic level and weak hydrodynamic activity. A second situation occurred in the months of fall and winter, which showed increased salinity, hydrodynamics and macrobenthos organisms. These results which contrast with previous studies carried out in the area, were attributed to failure in macrozoobenthos recruitments during summer period, especially of the bivalve Erodona mactroides Bosc, 1802 and the tanaid Kalliapseuses schubartii Mañe-Garzón, 1949. This results showed that recruitments of dominant species were influenced by salinity and hydrodynamic conditions.Objetiva-se analisar e relacionar a variabilidade espaço-temporal de uma associação macrozoobentônica com as características do substrato e variações da salinidade, numa enseada da região estuarina da Lagoa dos Patos. Amostragens mensais entre setembro de 2002 e agosto de 2003 foram realizadas em seis pontos de coleta distantes 90 m entre si. Em cada ponto foram tomadas três amostras biológicas com tubo extrator de 10 cm de diâmetro, uma amostra para análise do sedimento, medidas quinzenais da topografia do fundo e dados diários de temperatura e salinidade. Foram identificadas duas situações ambientais e bióticas bem definidas: uma correspondente aos meses de primavera e verão com baixas densidades do macrozoobentos, baixos valores de salinidade e pouca variação no nível do substrato, refletindo neste caso uma menor atividade hidrodinâmica. A outra situação ocorreu nos meses de outono e inverno, que mostrou uma situação oposta em relação às variáveis bióticas e abióticas. Esses resultados, que contrariam trabalhos anteriores efetuados na região, foram atribuídos a falhas nos recrutamentos do macrozoobentos durante o período de verão, especialmente do bivalve Erodona mactroides Bosc, 1802 e do tanaidáceo Kalliapseudes schubartii Mañe-Garzón, 1949. Verificou-se que os recrutamentos das espécies dominantes foram influenciados pelas condições de salinidade e pela hidrodinâmica.

  3. Ecologia de comunidades de insetos bentônicos (Ephemeroptera, Plecoptera e Trichoptera, em córregos do parque ecológico de Goiânia, Goiás, Brasil Ecology of benthic insects communi ites (Ephemeroptera, Plecoptera and Trichoptera in streams at parque ecológico de Goiânia, Goiás, Brazil

    Directory of Open Access Journals (Sweden)

    Leandro Gonçalves Oliveira

    1997-12-01

    Full Text Available Relationships among some abiotic factors (temperature, velocity, flow, conductivity, oxy-reduction potential and pH and the seazonal density of benthic insects (immature forms of the orders Ephemeroptera, Plecoptera and Trichoptera at the Parque Ecológico de Goiânia, Goiás are studied. An area of 1m² was sampled and abiotic factors were recorded in 4 sites from August/1994 to July/1995. The faunistic composition was 75% Ephemeroptera, 1% Plecoptera and 24% Trichoptera. The data suggest the water velocity and flow as the main factors that determined the aquatic insects abundance.

  4. Efecto del reemplazo de la vegetación nativa de ribera sobre la comunidad de macroinvertebrados bentónicos en arroyos de climas templados, Chile central Replacement effect of riparian native vegetation on benthic macroinvertebrates community in temperate climate streams, Central Chile

    Directory of Open Access Journals (Sweden)

    Gabriela Mancilla

    2009-12-01

    Full Text Available El aporte de materia orgánica desde la vegetación ribereña es determinante en la estructura y complejidad de los sistemas fluviales; es identificado como el mayor aporte energético en ríos y una fuente importante de alimento para macroinvertebrados en arroyos de cabecera. No obstante, el paisaje ribereño ha sido altamente degradado por actividades humanas, lo que ha afectado la estructura y composición de las comunidades acuáticas. El presente estudio se desarrolló en Chile central (región del Biobío donde se concentra una intensa actividad forestal con especies exóticas. Se seleccionaron ríos de bajo orden (The organic matter from riparian vegetation is determined by the structure and complexity of streams. It presents a higher energetic input to streams as well as important source of food for macroinvertebrates in head streams. In spite of its importance, riparian landscape has been rapidly degraded by human activity, this affects structure and composition of the aquatic community. The present study was made in Central Chile (Biobio Region which has intensive forest activity with exotic species. Small streams were selected (< 3 order, because they are very particularly sensitive to changes in land use. The sites were grouped identified according to native forest land cover larger than 20% (group 1 and smaller than 20% (group 2. Significant differences (p< 0.05 in Plecoptera abundance (p < 0.05 were found between the two groups. Differences in trophic groups were significant for shredders and predators increased and gathering-collectors decreased their abundance, with native cover smaller than 20%. This showed the dependent on allochthonous material. The vegetation cover and community parameters correlations showed that Diversity (W increased with higher percentage of watershed covered by native vegetation and exotic species mix. Results suggest that a buffer conservation area of native riparian vegetation is necessary in streams and rivers in order to maintain the structure and diversity of macroinvertebrates and health of these ecosystems.

  5. Tailed Radio Sources in the CDFS Field

    Indian Academy of Sciences (India)

    S. Dehghan; M. Johnston-Hollitt; M. Mao; R. P. Norris; N. A. Miller; M. Huynh

    2011-12-01

    Using 1.4 GHz ATCA & VLA images with 5.5 GHz ATCA data, we present a sample of 12 bent-tailed galaxies over the 4 deg2 area of the Chandra Deep Field South (CDFS). We find 10 new sources, one of which is possibly the highest red-shift bent-tailed galaxy detected at ∼ 2.

  6. Influence of the chemical modification and content of the clay on the mechanical properties of polypropylene and national bentonite composites; Influencia da modificacao quimica e do teor de argila nas propriedades mecanicas de compositos de polipropileno e bentonita nacional

    Energy Technology Data Exchange (ETDEWEB)

    Libano, Elaine V.D.G., E-mail: elainelibano@uezo.rj.gov.br [Centro Universitario Estadual da Zona Oeste - UEZO - RJ (Brazil); Pacheco, Elen B.A.V.; Visconte, Leila L.Y. [Universidade Federal do Rio de Janeiro - UFRJ, Instituto de Macromoleculas Professora Eloisa Mano - IMA, RJ (Brazil)

    2011-07-01

    The polypropylene/national clay composite was prepared by melt intercalation in a counter-rotating twin screw extruder, using bentonite as filler either in the natural (BENT) form or modified with the ammonium salt, cetyltrimethylammonium chloride (BENT-org). The clay was used in 1, 3 and 5%w. The influence of the modification and content of clay on the mechanical properties of this system was analysed. The analyses of infrared spectroscopy (FTIR) and X-ray diffraction (XRD) showed that clay organophilization did occur. The tensile modulus and the tensile strength at the yield point were not affected by chemical modification (BENT and BENT-org) or clay content. On the other hand, it was evidenced that the elongation at the yield point decreased with the addition of BENT and BENT-org to polypropylene. According to the thermogravimetric results, it was evidenced that the incorporation of clay into polypropylene improved thermal stability of the polymer in the composites with 5%w of BENT and 3 and 5%w of BENT-org. (author)

  7. Drama, drive and sensuous appeal

    DEFF Research Database (Denmark)

    Bonde, Lars Ole

    2002-01-01

    Introduction to Bent Lorentzen and his music, with focus on the piano music. Booklet accomapnying a complete recording of the piano works by Erik Kaltoft......Introduction to Bent Lorentzen and his music, with focus on the piano music. Booklet accomapnying a complete recording of the piano works by Erik Kaltoft...

  8. The "Global" Formulation of Thermodynamics and the First Law: 50 Years On

    Science.gov (United States)

    Gislason, Eric A.; Craig, Norman C.

    2011-01-01

    Nearly 50 years ago, Henry Bent published his groundbreaking article in this "Journal" introducing the "global" formulation of thermodynamics. In the following years, the global formulation was elaborated by Bent and by one of the present authors. The global formulation of the first law focuses on conservation of energy and the recognition that…

  9. IT-projekter er stadig risikable

    DEFF Research Database (Denmark)

    Harboe, Peter Georg

    2011-01-01

    Anmeldelse af Bent Flyvbjergs artikel i Harvard Business Review "Why your IT-projects may be riskier than you think"......Anmeldelse af Bent Flyvbjergs artikel i Harvard Business Review "Why your IT-projects may be riskier than you think"...

  10. Analysis of residual stress and hardness in regions of pre-manufactured and manual bends in fixation plates for maxillary advancement.

    Science.gov (United States)

    Araújo, Marcelo Marotta; Lauria, Andrezza; Mendes, Marcelo Breno Meneses; Claro, Ana Paula Rosifini Alves; Claro, Cristiane Aparecida de Assis; Moreira, Roger William Fernandes

    2015-12-01

    The aim of this study was to analyze, through Vickers hardness test and photoelasticity analysis, pre-bent areas, manually bent areas, and areas without bends of 10-mm advancement pre-bent titanium plates (Leibinger system). The work was divided into three groups: group I-region without bend, group II-region of 90° manual bend, and group III-region of 90° pre-fabricated bends. All the materials were evaluated through hardness analysis by the Vickers hardness test, stress analysis by residual images obtained in a polariscope, and photoelastic analysis by reflection during the manual bending. The data obtained from the hardness tests were statistically analyzed using ANOVA and Tukey's tests at a significance level of 5 %. The pre-bent plate (group III) showed hardness means statistically significantly higher (P < 0.05) than those of the other groups (I-region without bends, II-90° manually bent region). Through the study of photoelastic reflection, it was possible to identify that the stress gradually increased, reaching a pink color (1.81 δ / λ), as the bending was performed. A general analysis of the results showed that the bent plate region of pre-bent titanium presented the best results.

  11. Synthesis of assorted metal ions anchored alginate bentonite biocomposites for Cr(VI) sorption.

    Science.gov (United States)

    Gopalakannan, Venkatrajan; Periyasamy, Soodamani; Viswanathan, Natrayasamy

    2016-10-20

    Biocomposites were synthesized by dispersing bentonite (Bent) clay in a biopolymer namely alginate (Alg) and cross-linked with bi (Ca(2+)), tri (Ce(3+)) and tetravalent (Zr(4+)) metal ions viz., Ca@AlgBent, Ce@AlgBent and Zr@AlgBent composites respectively. The synthesized biocomposites were characterized by various instrumental techniques like FTIR, SEM and EDAX. Cr(VI) sorption capacities (SCs) of the biocomposites Ca@AlgBent, Ce@AlgBent and Zr@AlgBent were examined by batch process. Various adsorption influencing factors viz., contact time, dosage of the sorbent, pH of the medium, temperature, presence of common co-ions and initial Cr(VI) concentration were studied. Freundlich, Langmuir and Dubinin-Radushkevich (D-R) isotherm models were adopted to examine the adsorption equilibrium. Kinetics of the sorption process was carried out by pseudo-first-order and pseudo-second-order models. The nature of the sorption process was explained using thermodynamic parameters like ΔS°, ΔG° and ΔH° and a possible mechanism for the sorption of Cr(VI) onto the biocomposites was given. The application of the biocomposites at field conditions was also examined by testing it with industrial water. The regeneration studies were carried to know about the reusability of the biocomposites.

  12. NMR Evidence for a Planar Arene Intermediate in the Electron-Transfer Induced Eta 6 to Eta 4 Hapticity Change of a Rhodium Arene Complex

    Science.gov (United States)

    1989-07-01

    complex. Elschenbroich and co-workers2 8 observed large differences in coupling constants for the protons of the bent benzene ring in the ESR spectrum...characterization by Elschenbroich , et al., of the bent arene 19-electron complex [(n4-C6H6 )Cr(C 6H6 )3- 28, it rust be considered that bent arene structures...Koelle, U.; Fuss, B.; Rajasekharan, M.V.; Ramakrishna, B.L. Ammeter, J.H.; Boehm, M.C. J. Amer. Chem. Soc., 1984, 206, 4152. 28. Elschenbroich , Ch

  13. China Tries to Tap Cleaner Energy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ "The country is bent on reducing its reliance on dwindling fossil fuels and want to pursue sustainable energy development," said Shi Dinghuan, a director from the Ministry of Science and Technology.

  14. 29 CFR 1918.62 - Miscellaneous auxiliary gear.

    Science.gov (United States)

    2010-07-01

    ... than 5 percent; when a link is bent, twisted or otherwise damaged; or when a link has a raised scarf or... for hoisting shall be bolts and nuts, drive screws (helically threaded nails), annular threaded...

  15. 29 CFR 1917.42 - Miscellaneous auxiliary gear.

    Science.gov (United States)

    2010-07-01

    ... has increased the length of a measured section by more than five percent; when a link is bent, twisted..., drive screws (helically threaded nails), annular threaded nails or fastenings of equivalent...

  16. 78 FR 47486 - Joint Failure on Continuous Welded Rail Track

    Science.gov (United States)

    2013-08-05

    ... welded rail (CWR), plan contents. The plan must include procedures that prescribe the scheduling and... failure for which railroad personnel must inspect, including, at a minimum, (i) loose, bent, or...

  17. LC/IRMS analysis: A powerful technique to trace carbon flow in microphytobenthic communities in intertidal sediments

    NARCIS (Netherlands)

    Moerdijk-Poortvliet, T.C.W.; Stal, L.J.; Boschker, H.T.S.

    2014-01-01

    Microphytobenthic communities are important for primary production in intertidal marine sediments. Extracellular polymeric substances (EPS), comprising polysaccharides and proteins, play a key role in the structure and functioning of microphytobenthic biofilms and allow interactions between the bent

  18. Robottens Anatomi

    DEFF Research Database (Denmark)

    Nørgaard, Bent

    2009-01-01

    Videnskabsteater om robotter med bl.a Baard Owe, Steen Rasmussen, Musik :Hans Sydow, Scenografi: Cathia Hauberg Engel, Visuals: Anders Boe/Mikkel Larris, Koncept: Mikael Valeur, Willie Flint, Mimo Antabi, Bent Nørgaard...

  19. 49 CFR 213.119 - Continuous welded rail (CWR); plan contents.

    Science.gov (United States)

    2010-10-01

    ... following items: (i) Loose, bent, or missing joint bolts; (ii) Rail end batter or mismatch that contributes... amount and length of rail end batter or ramp on each rail end; the amount of tread mismatch; the...

  20. Ultra-relativistic heavy-ion physics with AFTER@LHC

    CERN Document Server

    Rakotozafindrabe, A; Brodsky, S J; Chambert, V; Didelez, J P; Genolini, B; Ferreiro, E G; Fleuret, F; Hadjidakis, C; Lansberg, J P; Rosier, P; Schienbein, I; Scomparin, E; Uggerhoj, U I

    2012-01-01

    We outline the opportunities for ultra-relativistic heavy-ion physics which are offered by a next generation and multi-purpose fixed-target experiment exploiting the proton and ion LHC beams extracted by a bent crystal.

  1. Realization of robust photonic crystal waveguides designed to reduce out-of-plane scattering

    DEFF Research Database (Denmark)

    Arentoft, Jesper; Kristensen, Martin; Søndergaard, Thomas;

    2001-01-01

    We have realized environmentally stable silicon-on-insulator based photonic crystal waveguides. The waveguide structure is designed to minimize scattering at semiconductor/hole interfaces. Transmission measurements and IR pictures indicate efficient guiding through straight and bent waveguides....

  2. Ultra-relativistic heavy-ion physics with AFTER@LHC

    DEFF Research Database (Denmark)

    Rakotozafindrabe, A.; Arnaldi, R.; Brodsky, Stanley;

    2013-01-01

    We outline the opportunities for ultra-relativistic heavy–ion physics which are offered by a next generation and multi-purpose fixed-target experiment exploiting the proton and ion LHC beams extracted by a bent crystal....

  3. 76 FR 18524 - Aluminum Extrusions From the People's Republic of China: Final Determination of Sales at Less...

    Science.gov (United States)

    2011-04-04

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE... Apodaca, AD/CVD Operations, Office 8, Import Administration, International Trade Administration, U.S..., punched, notched, bent, stretched, knurled, swedged, mitered, chamfered, threaded, and spun. The...

  4. Glaucous-winged gull nesting on Amchitka Island

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The glaucous-winged gull (Larus glaucescens) is the most common gull in the north Pacific (Bent 1921, Murie 1959). It is also one of the most abundant permanent...

  5. Mosaiikpilte Norramaa köögist / Moonika Siimets

    Index Scriptorium Estoniae

    Siimets, Moonika, 1980-

    2009-01-01

    Norra reisist: Väiketootja Inger Rosenfeldi juustu edust Prantsusmaal, Ameerikas ja Norras; 1993. aasta kokandusolümpia "Bocuse d`Or" võitjast Bent Stiansenist; norralaste toitumisharjumustest; Preikestolen Fjellstue ökomajas asuva turismikeskuse restoranis pakutavatest roogadest.

  6. Simultaneous sorption of aqueous phenanthrene and phosphate onto bentonites modified with AlCl3 and CTMAB

    Institute of Scientific and Technical Information of China (English)

    ZHU Runliang; ZHU Lizhong; ZHU Jianxi

    2007-01-01

    The Durpose of this work is to synthesize a new type of bentonite sorbent that can simultaneously remove both organic compounds and phosphate from water.Inorganic-organic bentonites(Al-CTMAB-Bent)were synthesized by modifying bentonites with both AlCl3 and cetyltrimethyl ammonium bromide(CTMAB).Simultaneous sorption of aqueous phenanthrene and phosphate onto Al-CTMAB-Bent was examined.Removal rates of phenanthrene and phosphate from water reached 96.3% and 90.2%,respectively,at their respective initial concentrations of 1mg/L and 5 mg/L and the added amount of Al-CTMAB-Bent was 1.25 g/L.The residual turbidity of the Al-CTMAB-Bent suspension decreased 81.4% compared to that of organobentonite suspension after a 1 h settling time.Thus,inorganic-organic bentonite can be used to treat wastewater containing both organic pollutants and phosphate.

  7. Pop / Lauri Tikerpe

    Index Scriptorium Estoniae

    Tikerpe, Lauri

    2006-01-01

    Heliplaatidest: Stereotyp "Keepin' Me", Bent "Intercept!", The Mars Volta "Amputechture", X-press 2 "Makeshift Feelgood", Kosmikud "Pulmad ja matused", Beck "The Information", Ursula "Armastan end aeglaselt", Envy "Insomniac Doze", Joe Colley & Jason Lescalleet "Annihilate This Week"

  8. GrB-TWEAK: A Potential Novel Biologic for NSCLC Therapy

    Science.gov (United States)

    2015-09-01

    a pattern of disease progression, and resemble stages in neurogenesis. Cancer Cell 2006; 9: 157–173. 55 Stupp R, Mason WP, van den Bent MJ, Weller M...Hegi ME, Mason WP, van den Bent MJ, Taphoorn MJ, Janzer RC et al. Effects of radiotherapy with concomitant and adjuvant temozolomide versus radiotherapy...520. 172 Agemy L, Friedmann-Morvinski D, Kotamraju VR, Roth L, Sugahara KN, Girard OM et al. Targeted nanoparticle enhanced proapoptotic peptide as

  9. Salles, Sergio. Paul Ricoeur e o humanismo jurídico moderno: O reconhecimento do sujeito de direito. Études Ricoeuriennes / Ricoeur Studies vol. 2, no. 2 (2011: 106–117

    Directory of Open Access Journals (Sweden)

    ERRS ERRS

    2012-01-01

    Full Text Available As published, the authorship for this article is incorrect. Coauthor Hilda Helena Soares Bentes was omitted due to an editorial error. The correct citation is:Bentes, Hilda and Salles, Sergio. Paul Ricoeur e o humanismo jurídico moderno: O reconhecimento do sujeito de direito. Études Ricoeuriennes / Ricoeur Studies vol. 2, no. 2 (2011: 106–117.The online version reflects these changes.

  10. Monochromator design for the HADAS reflectometer in Jülich

    Science.gov (United States)

    Rücker, U.; Alefeld, B.; Kentzinger, E.; Brückel, Th

    2000-06-01

    A reflectometer with polarization analysis is being built on the basis of the HADAS spectrometer in the neutron guide hall at the research reactor FRJ-2 (DIDO) in Jülich. For obtaining the optimal flux at the sample position, the performances of several monochromator designs have been calculated, e.g. focusing mirrors, mosaic monochromator crystals and bent perfect crystal monochromators. Under the given geometrical limitations a double monochromator with bent perfect Si crystals and vertical focusing has the best performance.

  11. The superluminal radio source 4c 39. 25 as relativistic jet prototype. El cuasar superluminal 4C 93. 25 como prototipo de jet relativistia

    Energy Technology Data Exchange (ETDEWEB)

    Alberdi, A.; Gomez, J.L.; Marcaide, J.M.

    1993-01-01

    We have developed a numerical code which solves the synchrotron radiation transfer equations to compute the total and polarized emission of bent shocked relativistic jets, and we have applied it to reproduce the compact structure, kinematic evolution of the superluminal radio source 4C 39.25 contains a bent relativistic jet which is misaligned relative to the observer near the core region, leading to a relatively low core brightness. (Author) 12 refs.

  12. Hyggeligt, men lavt til loftet, eller er det plat at have det godt

    DEFF Research Database (Denmark)

    Klausen, Søren Harnow

    2010-01-01

    Undersøger hvordan forskellige litterære fremstillinger - bl.a. hos Tage Skou-Hansen, Bent Vinn Nielsen, George Eliot og Virginia Woolf - kan være med til at kvalificere diskussionen om velfærdsstaten.......Undersøger hvordan forskellige litterære fremstillinger - bl.a. hos Tage Skou-Hansen, Bent Vinn Nielsen, George Eliot og Virginia Woolf - kan være med til at kvalificere diskussionen om velfærdsstaten....

  13. Construction and analysis of cryptographic functions

    CERN Document Server

    Budaghyan, Lilya

    2015-01-01

    This book covers novel research on construction and analysis of optimal cryptographic functions such as almost perfect nonlinear (APN), almost bent (AB), planar and bent functions. These functions have optimal resistance to linear and/or differential attacks, which are the two most powerful attacks on symmetric cryptosystems. Besides cryptographic applications, these functions are significant in many branches of mathematics and information theory including coding theory, combinatorics, commutative algebra, finite geometry, sequence design and quantum information theory. The author analyzes equ

  14. Evaluation of low back pain risks in a beef skinning operation.

    Science.gov (United States)

    Das, B; Sengupta, A K

    2000-01-01

    The low back pain risks in a beef skinning operation at a high stand kill floor workstation was evaluated. The increases in compressive forces at lower back (L5/S1) between normal slump (back angle 25 degrees, measured in the sagittal plane) and severe (45 degrees ) and between normal slump and very severe (70 degrees ) bent back postures were 387 N or 28% and 616 N or 45%, respectively. The high spine load coupled with high level of repetition can have a high probability of fatigue failure in the spine structural members. Non-neutral back posture for a large portion of the total work time can be a low back pain risk factor. The videotape analysis showed that the times involved during the task performance for the bent back (more than 25 degrees ) and severe bent back (more than 45 degrees ) were 48.4 and 33.5% of the total cycle time, respectively. The upper limit from OWAS (Ovako Working Posture Analysis System) for bent back posture is 30% of the total cycle time. The bent and twisted back posture (both more than 25 degrees ) time was 10.4% compared to OWAS limit of 5%. This indicated that actions are needed in the near future to alleviate the risk of low back pain. Ergonomics redesign of the workstation was recommended for the operation.

  15. Numerical analysis of dimension precision of U-shaped aluminium profile rotary stretch bending

    Institute of Scientific and Technical Information of China (English)

    YU Zhong-qi; LIN Zhong-qin

    2007-01-01

    In order to enhance the dimension precision of bent part, advanced bending technologies is requested recently. Rotary stretch bending(RSB) is a suitable technology to realize high precision of bent part. The effect of processing parameters, namely the side pressure and the stretching force, on the dimension precision of aluminium profile RSB part was studied by finite element method. The numerical simulation of the U-shaped aluminium profile RSB was carried out, and the validity of the simulation was checked. Parametric analysis shows that the section distortion of the U-shaped profile LY12M bent part decreases with the increasing of the side pressure, whereas the springback of curvature increases, and that both of the section distortion and the springback of curvature decrease with the increasing of the stretching force, moreover, the uniformity of curvature of the bent part is clearly enhanced with the increasing of the stretching force. The results above prove that RSB technology can better improve the dimension precision of aluminium profile bent part.

  16. Crystals in the LHC

    CERN Multimedia

    Antonella Del Rosso

    2012-01-01

    Bent crystals can be used to deflect charged particle beams. Their use in high-energy accelerators has been investigated for almost 40 years. Recently, a bent crystal was irradiated for the first time in the HiRadMat facility with an extreme particle flux, which crystals would have to withstand in the LHC. The results were very encouraging and confirmed that this technology could play a major role in increasing the beam collimation performance in future upgrades of the machine.   UA9 bent crystal tested with a laser. Charged particles interacting with a bent crystal can be trapped in channelling states and deflected by the atomic planes of the crystal lattice (see box). The use of bent crystals for beam manipulation in particle accelerators is a concept that has been well-assessed. Over the last three decades, a large number of experimental findings have contributed to furthering our knowledge and improving our ability to control crystal-particle interactions. In modern hadron colliders, su...

  17. On the construction of cryptographically strong Boolean functions with desirable trade-off

    Institute of Scientific and Technical Information of China (English)

    REN Kui; PARK Jaemin; KIM Kwangjo

    2005-01-01

    This paper proposes a practical algorithm for systematically generating strong Boolean functions (f:GF(2)n→GF(2))with cryptographic meaning. This algorithm takes bent function as input and directly outputs the resulted Boolean function in terms of truth table sequence. This algorithm was used to develop two classes of balanced Boolean functions, one of which has very good cryptographic properties: nl(f)=22k-1-2k+2k-2 (n=2k), with the sum-of-squares avalanche characteristic off satisfying σf=24k+23k+2+23k+23k-2 and the absolute avalanche characteristic of △f satisfying △f=2k+1. This is the best result up to now compared to existing ones. Instead of bent sequences, starting from random Boolean functions was also tested in the algorithm. Experimental results showed that starting from bent sequences is highly superior to starting from random Boolean functions.

  18. Zig-zag twins and helical phase transformations.

    Science.gov (United States)

    Ganor, Yaniv; Dumitrică, Traian; Feng, Fan; James, Richard D

    2016-04-28

    We demonstrate the large bending deformation induced by an array of permanent magnets (applied field ∼0.02 T) designed to minimize poles in the bent state of the crystal. Planar cantilevers of NiMnGa (5M modulated martensite) ferromagnetic shape memory alloy deform into an arched shape according to theory, with a zig-zag microstructure that complies with the kinematic and magnetic compatibility between adjacent twin variants. A general theory of bent and twisted states is given, applicable to both twinning and austenite/martensite transformations. Some of these configurations achieve order-of-magnitude amplification of rotation and axial strain. We investigate also atomistic analogues of these bent and twisted configurations with perfect interfaces between phases. These mechanisms of large deformation, induced by small magnetic fields or temperature changes, have potential application to the development of new actuation technologies for micro-robotic systems.

  19. [Causes of camptocormia].

    Science.gov (United States)

    Glocker, F X; Berninger, U G

    2013-08-01

    In this society with an ever increasing number of the elderly there is an increasing number of causes of a bent spine syndrome (camptocormia/dropped head syndrome). The causes include neurological, neuro-orthopedic, rheumatological and psychiatric disorders. Parkinson's disease, dystonia and neuromuscular diseases (motor neuron disease, myositis and muscular dystrophy) with weakness of the axial muscles may result in bent spine syndrome and is often combined with a dropped head. Disc herniation, hypertrophic spondylosis or pseudospondylolisthesis with spinal narrowing may lead to an abnormal flexion of the trunk. Ankylosing spondylitis can produce a disabling bent spine syndrome. Camptocormia may also be mimicked by osteoporotic fractures of the vertebral bones with wedge-shaped vertebrae. In some cases camptocormia is related to a psychogenic disorder.

  20. Observation of channeling for 6500 GeV/c protons in the crystal assisted collimation setup for LHC

    Science.gov (United States)

    Scandale, W.; Arduini, G.; Butcher, M.; Cerutti, F.; Garattini, M.; Gilardoni, S.; Lechner, A.; Losito, R.; Masi, A.; Mirarchi, D.; Montesano, S.; Redaelli, S.; Rossi, R.; Schoofs, P.; Smirnov, G.; Valentino, G.; Breton, D.; Burmistrov, L.; Chaumat, V.; Dubos, S.; Maalmi, J.; Puill, V.; Stocchi, A.; Bagli, E.; Bandiera, L.; Germogli, G.; Guidi, V.; Mazzolari, A.; Dabagov, S.; Murtas, F.; Addesa, F.; Cavoto, G.; Iacoangeli, F.; Ludovici, L.; Santacesaria, R.; Valente, P.; Galluccio, F.; Afonin, A. G.; Chesnokov, Yu. A.; Durum, A. A.; Maisheev, V. A.; Sandomirskiy, Yu. E.; Yanovich, A. A.; Kovalenko, A. D.; Taratin, A. M.; Denisov, A. S.; Gavrikov, Yu. A.; Ivanov, Yu. M.; Lapina, L. P.; Malyarenko, L. G.; Skorobogatov, V. V.; James, T.; Hall, G.; Pesaresi, M.; Raymond, M.

    2016-07-01

    Two high-accuracy goniometers equipped with two bent silicon crystals were installed in the betatron cleaning insertion of the CERN Large Hadron Collider (LHC) during its long shutdown. First beam tests were recently performed at the LHC with 450 GeV/c and 6500 GeV/c stored proton beams to investigate the feasibility of beam halo collimation assisted by bent crystals. For the first time channeling of 6500 GeV/c protons was observed in a particle accelerator. A strong reduction of beam losses due to nuclear inelastic interactions in the aligned crystal in comparison with its amorphous orientation was detected. The loss reduction value was about 24. Thus, the results show that deflection of particles by a bent crystal due to channeling is effective for this record particle energy.

  1. Monitoring of Moisture in Transformer Oil Using Optical Fiber as Sensor

    Directory of Open Access Journals (Sweden)

    S. Laskar

    2013-01-01

    Full Text Available This paper describes an optical fiber sensor and temperature sensor-based instrumentation system to measure the moisture content in transformer oil. The sensor system consists of (i Diode Laser Source, (ii a bare and bent multimode fiber as sensor probe, (iii an LDR as detector, (iv LM35-based temperature sensor, and (v microcontroller system having a trained ANN for processing and calibration. The bare and bent optical fiber sensor and the temperature sensor LM35 are used to provide the measures of refractive index (RI and temperature of a transformer oil sample. An ATmega32-microcontroller-based system with trained ANN algorithm has been developed to determine the moisture content of the transformer oil sample by sampling the readings of the bare bent optical fiber sensor and the temperature sensor.

  2. Bend-Induced Distortion in Large Mode Area Holey Fibre

    Institute of Scientific and Technical Information of China (English)

    TAN Xiao-Ling; GENG You-Fu; ZHANG Tie-Li; WANG Wei-Neng; WANG Peng; YAO Jian-Quan

    2008-01-01

    A simplified scheme of bend-induced mode distortion is introduced into bent holey fibres,the distorted mode distribution and mode effective area reduction are investigated using the finite difference method.Numerical results show that the modes of bent holey fibres with small bend radius shift away from the core and are deformed greatly,and the mode areas drop significantly as the bend radius decreases,which severely affects the fibre laser performance.The propagation characteristics of bent holey fibres at given wavelength are determined by fill factor and normalized bend radius.Finally,the transition normalized bend radius that represents the location of the mode area beginning to fall off is obtained.

  3. Gode spisevaner læres gennem smag, sprog og sanser

    DEFF Research Database (Denmark)

    Mikkelsen, Bent Egberg; Mikkelsen, Mette Vang

    2013-01-01

    Frokostordninger i dagtilbuddene er kommet for at blive. Men det er vigtigt, at ordningerne udvikles og fastholdes omkring dagtilbuddenes centrale kerneopgaver, så de ikke ender som passive bespisningstilbud. Det skriver Bent Egberg Mikkelsen og Mette Vang Mikkelsen, forskere ved Aalborg Universi......Frokostordninger i dagtilbuddene er kommet for at blive. Men det er vigtigt, at ordningerne udvikles og fastholdes omkring dagtilbuddenes centrale kerneopgaver, så de ikke ender som passive bespisningstilbud. Det skriver Bent Egberg Mikkelsen og Mette Vang Mikkelsen, forskere ved Aalborg...

  4. On the magnetostatics of chains of magnetic nanoparticles

    DEFF Research Database (Denmark)

    Phatak, C.; Pokharel, R.; Beleggia, Marco

    2011-01-01

    A novel approach is presented for the computation of the magnetostatic energy of straight and bent chains of identical, uniformly magnetized particles of arbitrary shape. The formalism relies on the concept of the magnetometric tensor field, and allows for closed form expressions for the magnetos......A novel approach is presented for the computation of the magnetostatic energy of straight and bent chains of identical, uniformly magnetized particles of arbitrary shape. The formalism relies on the concept of the magnetometric tensor field, and allows for closed form expressions...

  5. Multivariate Generalized Linear Mixed Models with High Complexity / Modèles linéaires généralisés mixtes multivariés avec complexité élevée

    DEFF Research Database (Denmark)

    Labouriau, Rodrigo

    The theory of exponential dispersion models (EDM), for which Bent Jørgensen made substantial contributions, provides a flexible framework of models alternative to the classic Gaussian linear models (e.g. generalized linear models and additive models). I review some multivariate extensions of thos...... aux EDMs pour bien représenter et interpréter les questions biologiques d'intérêt. Bent Jørgensen prônait des idées similaires dans son travail depuis les années 1980....

  6. WD-XRA technique in multiphase flow measuring

    Energy Technology Data Exchange (ETDEWEB)

    Gogolev, A.S.; Cherepennikov, Yu.M.; Vukolov, A.V. [Tomsk Polytechnic University, Lenin Avenue 30, Tomsk 634050 (Russian Federation); Rezaev, R.O. [Tomsk Polytechnic University, Lenin Avenue 30, Tomsk 634050 (Russian Federation); Nuclear University MEPhI, Kashirskoye Shosse 31, Moscow 115409 (Russian Federation); Stuchebrov, S.G. [Tomsk Polytechnic University, Lenin Avenue 30, Tomsk 634050 (Russian Federation); Hampai, D. [INFN Laboratori Nazionali di Frascati, Via E. Fermi 40, 00044 Frascati (Italy); Dabagov, S.B. [INFN Laboratori Nazionali di Frascati, Via E. Fermi 40, 00044 Frascati (Italy); Nuclear University MEPhI, Kashirskoye Shosse 31, Moscow 115409 (Russian Federation); RAS P.N. Lebedev Physical Institute, Lenin Avenue 53, Moscow 119991 (Russian Federation); Liedl, A.; Polese, C. [INFN Laboratori Nazionali di Frascati, Via E. Fermi 40, 00044 Frascati (Italy)

    2015-07-15

    A new technique to perform the analysis of multiphase fluid flow based on wave dispersive X-ray absorptiometry is suggested. The numerical simulation and comparison of this technique with currently used approaches are provided and a way to increase the luminosity intensity is found that includes the usage the X-ray focusing optics by a bent crystal and a polycapillary semilens. Based on numerical simulation of radiation spectrum the influence of the bent crystal on the luminosity is evaluated and experimentally shown the advantages of using the multicapillary optics.

  7. WD-XRA technique in multiphase flow measuring

    Science.gov (United States)

    Gogolev, A. S.; Cherepennikov, Yu. M.; Vukolov, A. V.; Rezaev, R. O.; Stuchebrov, S. G.; Hampai, D.; Dabagov, S. B.; Liedl, A.; Polese, C.

    2015-07-01

    A new technique to perform the analysis of multiphase fluid flow based on wave dispersive X-ray absorptiometry is suggested. The numerical simulation and comparison of this technique with currently used approaches are provided and a way to increase the luminosity intensity is found that includes the usage the X-ray focusing optics by a bent crystal and a polycapillary semilens. Based on numerical simulation of radiation spectrum the influence of the bent crystal on the luminosity is evaluated and experimentally shown the advantages of using the multicapillary optics.

  8. Relativistic jet with shock waves like model of superluminal radio source. Jet relativista con ondas de choque como modelo de radio fuentes superluminales

    Energy Technology Data Exchange (ETDEWEB)

    Alberdi, A.; Gomez, J.L.; Marcaide, J.M.

    1993-01-01

    The structure of the compact radio sources at milliarcsecond angular resolution can be explained in terms of shock waves propagating along bent jets. These jets consist of narrow-angle cones of plasma flowing at bulk relativistic velocities, within tangled magnetic fields, emitting synchrotron radiation. We have developed a numerical code which solves the synchrotron radiation transfer equations to compute the total and polarized emission of bent shocked relativistic jets, and we have applied it to reproduce the compact structure, kenimatic evolution and time flux density evolution of the superluminal radio source 4C 39.25 and to obtain its jet physical parameters. (Author) 23 ref.

  9. Channeling collimation studies at the Fermilab Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Carrigan, Richard A.; Drozhdin, Alexandr I.; Fliller, Raymond P., III; Mokhov, Nikolai V.; Shiltsev, Vladimir D.; Still, Dean A.; /Fermilab

    2006-08-01

    Bent crystal channeling has promising advantages for accelerator beam collimation at high energy hadron facilities such as the LHC. This significance has been amplified by several surprising developments including multi-pass channeling and the observation of enhanced deflections over the entire arc of a bent crystal. The second effect has been observed both at RHIC and recently at the Tevatron. Results are reported showing channeling collimation of the circulating proton beam halo at the Tevatron. Parenthetically, this study is the highest energy proton channeling experiment ever carried out. The study is continuing.

  10. CARBON SEQUESTRATION ON SURFACE MINE LANDS

    Energy Technology Data Exchange (ETDEWEB)

    Donald H. Graves; Christopher Barton; Richard Sweigard; Richard Warner

    2005-06-22

    An area planted in 2004 on Bent Mountain in Pike County was shifted to the Department of Energy project to centralize an area to become a demonstration site. An additional 98.3 acres were planted on Peabody lands in western Kentucky and Bent Mountain to bring the total area under study by this project to 556.5 acres as indicated in Table 2. Major efforts this quarter include the implementation of new plots that will examine the influence of differing geologic material on tree growth and survival, water quality and quantity and carbon sequestration. Normal monitoring and maintenance was conducted and additional instrumentation was installed to monitor the new areas planted.

  11. Shear Piezoelectricity in Poly(vinylidenefluoride-co-trifluoroethylene): Full Piezotensor Coefficients by Molecular Modeling, Biaxial Transverse Response, and Use in Suspended Energy-Harvesting Nanostructures.

    Science.gov (United States)

    Persano, Luana; Catellani, Alessandra; Dagdeviren, Canan; Ma, Yinji; Guo, Xiaogang; Huang, Yonggang; Calzolari, Arrigo; Pisignano, Dario

    2016-09-01

    The intrinsic flexible character of polymeric materials causes remarkable strain deformations along directions perpendicular to the applied stress. The biaxial response in the shear piezoelectricity of polyvinylidenefluoride copolymers is analyzed and their full piezoelectric tensors are provided. The microscopic shear is exploited in single suspended nanowires bent by localized loading to couple flexural deformation and transverse piezoelectric response.

  12. Claire Danes's Star-Body, Teen Female Viewers and the Pluralisation of Authorship in Baz Luhrmann's "William Shakespeare's Romeo + Juliet"

    Science.gov (United States)

    Keam, Angela

    2008-01-01

    Teaching William Shakespeare's canonical tragedy "Romeo and Juliet" to teenagers in the context of the English classroom in Australia is not a particularly new pedagogical practice. In the year 2008, when many teachers (particularly those with a feminist bent such as I) are intent on guiding their students to decipher the ideological…

  13. Effects of sediment-spiked lufenuron on benthic macroinvertebrates in outdoor microcosms and single-species toxicity tests

    NARCIS (Netherlands)

    Brock, T.C.M.; Bas, D.A.; Belgers, J.D.M.; Bibbe, L.; Boerwinkel, M.C.; Crum, S.J.H.; Diepens, N.J.; Kraak, M.H.S.; Vonk, J.A.; Roessink, I.

    2016-01-01

    Sediment ecotoxicity studies were conducted with lufenuron to (i) complement the results of a water-spiked mesocosm experiment with this lipophilic benzoylurea insecticide, (ii) to explore the predictive value of laboratory single-species tests for population and community-level responses of bent

  14. Revitalizing the Nuclear Weapons Enterprise

    Science.gov (United States)

    2010-03-01

    units failing Nuclear Operational Readiness Inspections ( NORI ). In assessing the Air Force, the Schlesinger Task Force found a cause for these...all of the time. For example, the Air Force unit involved in the “Bent Spear” incident in 2007 had passed their NORI about 16 months earlier.52

  15. "Gone fishing": modeling diversity in work ethics

    NARCIS (Netherlands)

    Freyberg-Inan, A.; Koçer, R.G.

    2012-01-01

    In his "Anecdote Concerning the Lowering of Productivity", written in 1963, the West-German writer Heinrich Böll humorously contrasts the mindset of an enterprising capitalist, bent on the maximization of profit, with that of a person we might call a profit "satisficer," a maximizer of leisure or ha

  16. Light Armored Vehicle (LAV) Training Equipment Survey for the U.S. Marine Corps LAV-25.

    Science.gov (United States)

    1983-12-15

    unit *un dispositif de dtection des mouvements .a weapon motion sensing device de l’drme .a control unit * unbotier o cmmano .a TV monitor, used by the... fouling from the receiver. 9.2.7 Use clean, dry cloth to wipe buffer. 9.2.8 Mbve feed lever and cover labels to check spring tension. 9.2.9 Look for bent

  17. The effect of a varying Mg2+free concentration upon the kinetic behaviour of human liver L-type pyruvate kinase

    NARCIS (Netherlands)

    Sprengers, E.D.; Staal, Gerard E.J.

    1979-01-01

    We have proposed negative cooperativity for human liver L-type pyruvate kinase, a phenomenon also observed in: Lineweaver-Burk plots V⁻¹ versus [phosphoenolpyruvatel]⁻¹ were straight lines at low phosphoenolpyruvate concentrations, and bent downward near they axis (high phosphoenolpyruvate concentra

  18. Exercise physiology

    DEFF Research Database (Denmark)

    Kiens, Bente; Richter, Erik; Wojtaszewski, Jørgen

    2014-01-01

    The passing of Professor Bengt Saltin on September 12, 2014 truly marks the end of an era. As editor of the Journal of Applied Physiology and one of Bengt’s many collaborators and colleagues, I wanted the Journal to celebrate his many seminal contributions by means of an Editorial. Professor Bent...

  19. Engineer: The Professional Bulletin of Army Engineers, Jan-Apr 2010

    Science.gov (United States)

    2010-04-01

    their training. However, after the conclusion of conventional combat operations, our Soldiers faced a resil - ient and adaptive enemy bent on...an environment strewn with trash—or where children walk in open sewer drainage ditches, or where the purity of water or air is questioned— projects

  20. Direct mapping of light propagation in photonic crystal waveguides

    DEFF Research Database (Denmark)

    Bozhevolnyi, S.I.; Volkov, V.S.; Arentoft, J.;

    2002-01-01

    Using near-field optical microscopy, we directly map the propagation of light in the wavelength range of 1510-1560 nm along bent photonic crystal waveguides formed by removing a single row of holes in the triangular 400-nm-period lattice and connected to access ridge waveguides, the structure being...

  1. Power Production and Economical Feasibility of Tideng Tidal Stream Power Converter

    DEFF Research Database (Denmark)

    Parmeggiani, Stefano; Frigaard, Peter; Kofoed, Jens Peter;

    This report is a product of the contract between Aalborg University and TIDENG (by Bent Hilleke) on the evaluation and development of the TIDENG Tidal Energy Conversion System (TECS). The work has focused on the evaluation of the yearly power production of the device and its economical feasibility...

  2. Large Scale Glazed Concrete Panels

    DEFF Research Database (Denmark)

    Bache, Anja Margrethe

    2010-01-01

    existing buildings in and around Copenhagen that are covered with mosaic tiles or glazed tiles; buildings such as Nanna Ditzel’s House in Klareboderne, Arne Jacobsen’s gas station, Erik Møller’s Industriens Hus, Bent Helweg Møller’s Berlingske Hus, Arne Jacobsen’s Stellings Hus and Toms Chocolate Factories...

  3. Flexible, angle-independent, structural color reflectors inspired by morpho butterfly wings.

    Science.gov (United States)

    Chung, Kyungjae; Yu, Sunkyu; Heo, Chul-Joon; Shim, Jae Won; Yang, Seung-Man; Han, Moon Gyu; Lee, Hong-Seok; Jin, Yongwan; Lee, Sang Yoon; Park, Namkyoo; Shin, Jung H

    2012-05-08

    Thin-film color reflectors inspired by Morpho butterflies are fabricated. Using a combination of directional deposition, silica microspheres with a wide size distribution, and a PDMS (polydimethylsiloxane) encasing, a large, flexible reflector is created that actually provides better angle-independent color characteristics than Morpho butterflies and which can even be bent and folded freely without losing its Morpho-mimetic photonic properties.

  4. Away with Good Bantus: De-Linking African Language Literature from Culture, "Tribe" and Propriety

    Science.gov (United States)

    Mkhize, Nomalanga

    2016-01-01

    This paper argues that the "institutionalisation" model used by universities to spearhead the intellectualisation of African languages is a non-starter for taking African languages in new creative directions. The major constraint for African language literary culture is that written output has historically been heavily bent towards…

  5. Pediatric Glioblastoma Therapies Based on Patient-Derived Stem Cell Resources

    Science.gov (United States)

    2014-11-01

    cancerfactsfi gures/cancerfactsfi gures/cancer-facts-and- fi gures-2010 . 2. Stupp R , Mason WP , van den Bent MJ , Weller M , Fisher B , Taphoorn...Cell 13, 566–579. Powell, S., Szklarczyk, D., Trachana, K., Roth , A., Kuhn, M., Muller, J., Arnold, R., Rattei, T., Letunic, I., Doerks, T., et al

  6. Doubly curved imaging Bragg crystal spectrometer for X-ray astronomy

    DEFF Research Database (Denmark)

    Byrnak, B. P.; Christensen, Finn Erland; Westergaard, Niels Jørgen Stenfeldt

    1985-01-01

    An X-ray spectrometer which is sensitive in the 0.5-7-keV energy range and is intended for use onboard astronomical satellites has been studied. The Bragg reflected rays from a doubly bent crystal positioned downstream of the focal plane of a grazing-incidence concentrator are focused along the a...

  7. Robust arkitektur

    DEFF Research Database (Denmark)

    Stylsvig Madsen, Ulrik

    2008-01-01

    derfor betinget af arkitekturens evne til gennem bygningen og dens struktur at skabe en række rige og åbne rumlige muligheder, som kan involvere brugerne og inspirere dem til at bruge de fysiske rammer i der dagligdag. Det er dog vigtigt, at dette mulighedsfelt er så åbent, at det gennem tiden kan optage...

  8. Garrison Project - Lake Sakakawea Oil and Gas Management Plan, North Dakota

    Science.gov (United States)

    2012-11-01

    sedge Carex haydenii Cloud sedge Cheilanthes feei Fee’s lipfern Chenopodium subglabrum Smooth...drummondii Drummond’s milkvetch Astragalus vexilliflexus Bent-flower milkvetch Carex athrostachya Jointed-spike...Mentzelia pumila Dwarf mentzelia Monotropa uniflora Indian-pipe Myosurus aristatus Sedge mousetail Pellaea

  9. Design Packing to Safely Mail Raw Spaghetti. Grades 3-5.

    Science.gov (United States)

    Rushton, Erik; Ryan, Emily; Swift, Charles

    This activity is designed to build creative skills based on an everyday problem. The scenario that sometimes packages are dropped and letters get bent is used. How can a special delivery be protected from such unfortunate mishaps? Students use their creative skills to determine a way to mail raw spaghetti. A way to safely package the raw spaghetti…

  10. Wire and Packing Tape Sandwiches

    Science.gov (United States)

    Rabinowitz, Sandy

    2009-01-01

    In this article, the author describes how students can combine craft wire with clear packing tape to create a two-dimensional design that can be bent and twisted to create a three-dimensional form. Students sandwich wire designs between two layers of tape. (Contains 1 online resource.)

  11. The human Y chromosome: a sole survivor

    NARCIS (Netherlands)

    Noordam, M.J.

    2012-01-01

    Het Y-chromosoom zorgt er niet alleen voor dat je man bent, maar is ook van groot belang voor de aanmaak van zaadcellen. Uit eerder onderzoek blijkt dat mannen met slecht zaad vaak stukjes van het Y-chromosoom missen. Michiel Noordam onderzocht of vermenigvuldiging van bepaalde grote delen van het Y

  12. AFTER@LHC: a precision machine to study the interface between particle and nuclear physics

    CERN Document Server

    Lansberg, J P; Brodsky, S J; Chambert, V; Didelez, J P; Genolini, B; Ferreiro, E G; Fleuret, F; Hadjidakis, C; Lorce, C; Rakotozafindrabe, A; Rosier, P; Schienbein, I; Scomparin, E; Uggerhoj, U I

    2014-01-01

    We outline the opportunities to study with high precision the interface between nuclear and particle physics, which are offered by a next generation and multi-purpose fixed-target experiment exploiting the proton and ion LHC beams extracted by a bent crystal.

  13. Studying the high x frontier with A Fixed-Target ExpeRiment at the LHC

    CERN Document Server

    Rakotozafindrabe, A; Arnaldi, R; Brodsky, S J; Chambert, V; Didelez, J P; Ferreiro, E G; Fleuret, F; Genolini, B; Hadjidakis, C; Lansberg, J P; Lorce, C; Rosier, P; Schienbein, I; Scomparin, E; Uggerhoj, U I

    2013-01-01

    The opportunities which are offered by a next generation and multi-purpose fixed-target experiment exploiting the proton and lead LHC beams extracted by a bent crystal are outlined. In particular, such an experiment can greatly complement facilities with lepton beams by unraveling the partonic structure of polarised and unpolarised nucleons and of nuclei, especially at large momentum fractions.

  14. Spin physics at A Fixed-Target ExpeRiment at the LHC (AFTER@LHC)

    CERN Document Server

    Rakotozafindrabe, A; Arnaldi, R; Brodsky, S J; Chambert, V; Didelez, J P; Ferreiro, E G; Fleuret, F; Genolini, B; Hadjidakis, C; Lansberg, J P; Lorce, C; Rosier, P; Schienbein, I; Scomparin, E; Uggerhoj, U I

    2013-01-01

    We outline the opportunities for spin physics which are offered by a next generation and multi-purpose fixed-target experiment exploiting the proton LHC beam extracted by a bent crystal. In particular, we focus on the study of single transverse spin asymetries with the polarisation of the target.

  15. 76 FR 6406 - Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to a...

    Science.gov (United States)

    2011-02-04

    ... concrete piles which will be excised down to the mud line. An additional three 24-in steel fender piles... piles cut to the mud line (includes 72 at fragmentation barrier, four at walkway, four at Bent 8... such as drilling or dredging, vibratory pile driving, and active sonar systems. The duration of...

  16. Approximations for the natural logarithm from solenoid-toroid correspondence

    CERN Document Server

    Semiz, Ibrahim

    2015-01-01

    It seems reasonable that a toroid can be thought of approximately as a solenoid bent into a circle. The correspondence of the inductances of these two objects gives an approximation for the natural logarithm in terms of the average of two numbers. Different ways of averaging give different approximants. They are expressions simpler than Taylor polynomials, and are meaningful over a wider domain.

  17. Modernism in School Reform: Promoting Private over Public Good

    Science.gov (United States)

    Nordgren, R. D.

    2016-01-01

    School reform in the past several decades has taken a "modernist" bent in that it has focused on quantitatively based accountability systems modeled after business (Ravitch, 2013; Tienken & Orlich, 2013). The author uses a model devised by a Finnish scholar to demonstrate that 1) these reforms are indeed modernist, and 2) the private…

  18. Interplay of nonlinearity and geometry in a DNA-related, Klein-Gordon model with long-range dipole-dipole interaction

    DEFF Research Database (Denmark)

    Archilla, J. F.R.; Christiansen, Peter Leth; Gaididei, Yuri Borisovich

    2002-01-01

    Most of the studies on mathematical models of DNA are limited to next neighbor interaction. However, the coupling between base pairs is thought to be caused by dipole interaction, and, when the DNA strand is bent, the distances between base pairs become shorter, therefore the interactions with di...

  19. Nieuwsbrief Nanotechnologie 16 - Rathenau Instituut lanceert website over nanotechnologie

    NARCIS (Netherlands)

    Walhout, B.

    2010-01-01

    Beste lezer, U ontvangt deze e-mail omdat u geabonneerd bent op de Nieuwsbrief Nanotechnologie van het Rathenau Instituut. Zoals u ziet is deze nieuwsbrief helemaal vernieuwd. Sinds 2003 informeert het Rathenau Instituut de politiek over nanotechnologie. Met de nieuwsbrief willen we u op de hoogte h

  20. 76 FR 18521 - Aluminum Extrusions From the People's Republic of China: Final Affirmative Countervailing Duty...

    Science.gov (United States)

    2011-04-04

    ... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF COMMERCE...: John Conniff, AD/CVD Operations, Office 3, Import Administration, U.S. Department of Commerce, Room...-length, machined, drilled, punched, notched, bent, stretched, knurled, swedged, mitered,...