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Sample records for crystallographic inversion centre

  1. Crystallographic mechanism of inverse twinning in ordered β′-CuZn alloy

    Institute of Scientific and Technical Information of China (English)

    毛卫民

    2000-01-01

    The basic process of mechanical twinning in β’-CuZn phase, as an example of B2 structured metals, has been analyzed under the rolling stresses. The behavior of inverse twinning in B2 structured metals is discussed in terms of mechanics and crystallographic stability. It is shown that the inverse twinning could remain the B2 structure, and the resulting strains will have the lowest resistance during the rolling deformation of the polycrystalline.

  2. Crystallographic mechanism of inverse twinning in ordered β'-CuZn alloy

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The basic process of mechanical twinning in β'-CuZn phase, as an example of B2 structured metals, has been analyzed under the rolling stresses. The behavior of inverse twinning in B2 structured metals is discussed in terms of mechanics and crystallographic stability. It is shown that the inverse twinning could remain the B2 structure, and the resulting strains will have the lowest resistance during the rolling deformation of the polycrystalline.

  3. On Room-Temperature Inversion of EPR Signals of P1 Centre in Synthetic Diamond

    Institute of Scientific and Technical Information of China (English)

    G. G. Fedoruk; O. N. Poklonskaya

    2009-01-01

    Room-temperature inversion of EPR absorption signals of P1 centre in synthetic diamond is studied by the tran-sient nutation technique. Use of the bichromatic field, consisting of a transverse microwave field and longitudinal radio frequency field, allows to investigate the dynamics of P1 centres in the same field configuration as in cw EPR spectrometers. It is shown that the annealing decreases the P1 centre concentration and, respectively, increases the spin-spin relaxation time. As a result, the periodic inversion (nutation) of the P1 centre absorption signal is observed longer. It is assumed that the P1 centre signal inversion, which was previously observed by cw EPR, might be caused by the Bloch-Siegert effect in the biehromatic field.

  4. 40-Godišnjica institucije Cambridge Crystallographic Data Centre posvećene pohranjivanju podataka o molekularnim i kristalnim strukturama -

    Directory of Open Access Journals (Sweden)

    Molčanov, K.

    2006-06-01

    Full Text Available The article is dedicated to 40th anniversary of The Cambridge Crystallographic Data Centre (CCDC, the world-known centre (http://www.ccdc.cam.ac.uk responsible for deposition and control of crystallographic data, including atomic coordinates that define the three-dimensional structures of organic molecules and metal complexes containing organic ligands. Cambride Structural Database (CSD, one among the first established electronic databases, nowadays is the most significant crystallographic database in the world. CSD has about 400,000 deposited structures. The use of the extensive database, which is growing rapidly, needs support of efficient and sophisticated software for searching, analysing and visualising structural data. The seminal role of CSD in the research related to crystallography, chemistry, material sciences, solid state physics and chemistry, life sciences, pharmacology, and in particular in drug design, has been documented in more than 1300 scientific papers. The important issues of CCDC are the accuracy of deposited data and development of software that enables a wide variety of applications. Such demanding project requires higly competent team of experts; thus the article brings into focus the scientific approach of the team based on the long tradition in crystallography, modelling and informatics. The article is not dedicated to 40th anniversary of the centre only, but it also reveals how Cambridge Structural Database can be used in the research and teaching. The use of electronic media and computer graphics makes “data mining" very efficient and useful but also esthetically appealing due to the molecular architecture. At the Rudjer Bošković Institute, Zagreb, Croatia there is The National Affiliated Centre of Cambridge Crystallographic Data Centre responsible for communication and dissemination of CSD in Croatia, Slovenia and Macedonia. The use of CSD is illustrated by two examples performed and published by the presenting

  5. Data-driven high-throughput prediction of the 3-D structure of small molecules: review and progress. A response to the letter by the Cambridge Crystallographic Data Centre.

    Science.gov (United States)

    Baldi, Pierre

    2011-12-27

    A response is presented to sentiments expressed in "Data-Driven High-Throughput Prediction of the 3-D Structure of Small Molecules: Review and Progress. A Response from The Cambridge Crystallographic Data Centre", recently published in the Journal of Chemical Information and Modeling, (1) which may give readers a misleading impression regarding significant impediments to scientific research posed by the CCDC.

  6. Searching for the inverse-Compton emission from bright cluster-centre radio galaxies

    CERN Document Server

    Hardcastle, M J

    2010-01-01

    We use deep archival Chandra and XMM-Newton observations of three of the brightest cluster-centre radio galaxies in the sky, Cygnus A, Hercules A and Hydra A, to search for inverse-Compton emission from the population of electrons responsible for the low-frequency radio emission. Using simulated observations, we derive robust estimates for the uncertainties on the normalization of an inverse-Compton component in the presence of the variations in background thermal temperature actually seen in our target objects. Using these, together with the pressures external to the lobes, we are able to place interesting upper limits on the fraction of the energy density in the lobes of Hydra A and Her A that can be provided by a population of relativistic electrons with standard properties, assuming that the magnetic field is not dominant; these limits are consistent with the long-standing idea that the energy density in these lobes is dominated by a non-radiating particle population. In Cygnus A, we find evidence in the ...

  7. Effects of hip joint centre mislocation on gait kinematics of children with cerebral palsy calculated using patient-specific direct and inverse kinematic models.

    Science.gov (United States)

    Kainz, Hans; Carty, Christopher P; Maine, Sheanna; Walsh, Henry P J; Lloyd, David G; Modenese, Luca

    2017-09-01

    Joint kinematics can be calculated by Direct Kinematics (DK), which is used in most clinical gait laboratories, or Inverse Kinematics (IK), which is mainly used for musculoskeletal research. In both approaches, joint centre locations are required to compute joint angles. The hip joint centre (HJC) in DK models can be estimated using predictive or functional methods, while in IK models can be obtained by scaling generic models. The aim of the current study was to systematically investigate the impact of HJC location errors on lower limb joint kinematics of a clinical population using DK and IK approaches. Subject-specific kinematic models of eight children with cerebral palsy were built from magnetic resonance images and used as reference models. HJC was then perturbed in 6mm steps within a 60mm cubic grid, and kinematic waveforms were calculated for the reference and perturbed models. HJC perturbations affected only hip and knee joint kinematics in a DK framework, but all joint angles were affected when using IK. In the DK model, joint constraints increased the sensitivity of joint range-of-motion to HJC location errors. Mean joint angle offsets larger than 5° were observed for both approaches (DK and IK), which were larger than previously reported for healthy adults. In the absence of medical images to identify the HJC, predictive or functional methods with small errors in anterior-posterior and medial-lateral directions and scaling procedures minimizing HJC location errors in the anterior-posterior direction should be chosen to minimize the impact on joint kinematics. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  8. Crystallographic Information Resources

    Science.gov (United States)

    Glasser, Leslie

    2016-01-01

    Crystallographic information provides the fundamental basis for understanding the properties and behavior of materials. This data, such as chemical composition, unit cell dimensions, space group, and atomic positions, derives from the primary literature--that is, from published experimental measurement or theoretical calculation. Although the…

  9. Macromolecular crystallographic estructure refinement

    Directory of Open Access Journals (Sweden)

    Afonine, Pavel V.

    2015-04-01

    Full Text Available Model refinement is a key step in crystallographic structure determination that ensures final atomic structure of macromolecule represents measured diffraction data as good as possible. Several decades have been put into developing methods and computational tools to streamline this step. In this manuscript we provide a brief overview of major milestones of crystallographic computing and methods development pertinent to structure refinement.El refinamiento es un paso clave en el proceso de determinación de una estructura cristalográfica al garantizar que la estructura atómica de la macromolécula final represente de la mejor manera posible los datos de difracción. Han hecho falta varias décadas para poder desarrollar nuevos métodos y herramientas computacionales dirigidas a dinamizar esta etapa. En este artículo ofrecemos un breve resumen de los principales hitos en la computación cristalográfica y de los nuevos métodos relevantes para el refinamiento de estructuras.

  10. Phaser crystallographic software.

    Science.gov (United States)

    McCoy, Airlie J; Grosse-Kunstleve, Ralf W; Adams, Paul D; Winn, Martyn D; Storoni, Laurent C; Read, Randy J

    2007-08-01

    Phaser is a program for phasing macromolecular crystal structures by both molecular replacement and experimental phasing methods. The novel phasing algorithms implemented in Phaser have been developed using maximum likelihood and multivariate statistics. For molecular replacement, the new algorithms have proved to be significantly better than traditional methods in discriminating correct solutions from noise, and for single-wavelength anomalous dispersion experimental phasing, the new algorithms, which account for correlations between F(+) and F(-), give better phases (lower mean phase error with respect to the phases given by the refined structure) than those that use mean F and anomalous differences DeltaF. One of the design concepts of Phaser was that it be capable of a high degree of automation. To this end, Phaser (written in C++) can be called directly from Python, although it can also be called using traditional CCP4 keyword-style input. Phaser is a platform for future development of improved phasing methods and their release, including source code, to the crystallographic community.

  11. A crystallographic perspective on sharing data and knowledge.

    Science.gov (United States)

    Bruno, Ian J; Groom, Colin R

    2014-10-01

    The crystallographic community is in many ways an exemplar of the benefits and practices of sharing data. Since the inception of the technique, virtually every published crystal structure has been made available to others. This has been achieved through the establishment of several specialist data centres, including the Cambridge Crystallographic Data Centre, which produces the Cambridge Structural Database. Containing curated structures of small organic molecules, some containing a metal, the database has been produced for almost 50 years. This has required the development of complex informatics tools and an environment allowing expert human curation. As importantly, a financial model has evolved which has, to date, ensured the sustainability of the resource. However, the opportunities afforded by technological changes and changing attitudes to sharing data make it an opportune moment to review current practices.

  12. Crystallographic topology and its applications

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, C.K.; Burnett, M.N. [Oak Ridge National Lab., TN (United States); Dunbar, W.D. [Simon`s Rock Coll., Great Barrington, MA (United States). Div. of Natural Sciences and Mathematics

    1996-10-01

    Geometric topology and structural crystallography concepts are combined to define a new area we call Structural Crystallographic Topology, which may be of interest to both crystallographers and mathematicians. In this paper, we represent crystallographic symmetry groups by orbifolds and crystal structures by Morse - functions. The Morse function uses mildly overlapping Gaussian thermal-motion probability density functions centered on atomic sites to form a critical net with peak, pass, pale, and pit critical points joined into a graph by density gradient-flow separatrices. Critical net crystal structure drawings can be made with the ORTEP-III graphics pro- An orbifold consists of an underlying topological space with an embedded singular set that represents the Wyckoff sites of the crystallographic group. An orbifold for a point group, plane group, or space group is derived by gluing together equivalent edges or faces of a crystallographic asymmetric unit. The critical-net-on-orbifold model incorporates the classical invariant lattice complexes of crystallography and allows concise quotient-space topological illustrations to be drawn without the repetition that is characteristic of normal crystal structure drawings.

  13. CIF (Crystallographic Information File): A Standard for Crystallographic Data Interchange

    Science.gov (United States)

    Brown, I. D.

    1996-01-01

    The Crystallographic Information File (CIF) uses the self-defining STAR file structure. This requires the creation of a dictionary of data names and definitions. A basic dictionary of terms needed to describe the crystal structures of small molecules was approved in 1991 and is currently used for the submission of papers to Acta Crystallographica C. A number of extensions to this dictionary are in preparation. By storing the dictionary itself as a STAR file, the definitions and relationships in the CIF dictionary become computer interpretable. This offers many possibilities for the automatic handling of crystallographic information. PMID:27805170

  14. The birth of the European Crystallographic Committee (ECC) and of the European Crystallographic Meetings (ECMs)

    Science.gov (United States)

    Authier, A.

    2010-01-01

    This article describes the circumstances of the establishment of the European Crystallographic Committee, now the European Crystallographic Association, a regional associate of the IUCr, and of the European Crystallographic Meetings.

  15. The Crystallographic Information File (CIF

    Directory of Open Access Journals (Sweden)

    I D Brown

    2006-11-01

    Full Text Available The Crystallographic Information File (CIF, owned by the International Union of Crystallography, is a file structure based on tag-value ASCII pairs with tags defined in machine-readable dictionaries. The crystallographic community publishes and archives large quantities of numeric information generated by crystal structure determinations, and CIF's acceptance was assured by its adoption as the submission format for Acta Crystallographica and by the obvious needs of the community. CIF's strength lies in its dictionaries, which define most of the concepts of crystallography; its weakness is the difficulty of writing software that exploits its full potential.

  16. Triboluminescence dominated by crystallographic orientation

    Science.gov (United States)

    Wang, Kuifang; Ma, Liran; Xu, Xuefeng; Wen, Shizhu; Luo, Jianbin

    2016-05-01

    Triboluminescence (TL) is an optical phenomenon that has a long and varied history with broad applications, such as damage detection, X-ray source, and mass health monitoring sensor. So far, the properties and mechanisms of TL remain not completely understood. The TL properties emitted during the sliding contact between Al2O3 and SiO2 surfaces were studied along different crystallographic orientations. In this study, the TL intensity of Al2O3 was significantly enhanced as Al2O3 surface was along a particular crystallographic orientation, which is an unconventional phenomenon. TL enhancement of Al2O3 was not affected by air atmosphere and atomic stocking mode of Al2O3. The enhancement mechanism of Al2O3 may be influenced by the surface state of Al2O3. This work provides a new method to control the intensity of TL and novel ideas to elucidate the TL mechanism.

  17. Crystallographic properties of fertilizer compounds

    Energy Technology Data Exchange (ETDEWEB)

    Frazier, A.W.; Dillard, E.F.; Thrasher, R.D.; Waerstad, K.R.; Hunter, S.R.; Kohler, J.J.; Scheib, R.M.

    1991-02-01

    This bulletin is a compilation of crystallographic data collected at NFERC on 450 fertilizer-related compounds. In TVA's fertilizer R and D program, petrographic examination, XRD, and infrared spectroscopy are combined with conventional chemical analysis methods in identifying the individual compounds that occur in fertilizer materials. This handbook brings together the results of these characterization studies and supplemental crystallographic data from the literature. It is in one-compound-per-page, loose-leaf format, ordered alphabetically by IUPAC name. Indexes provided include IUPAC name, formula, group, alternate formula, synonyms, x-ray data, optical data. Tables are given for solids, compounds in commercial MAP and DAP, and matrix materials in phosphate rock.

  18. Crystallographic groups and topology in Escher. (Spanish:Grupos cristalográficos y topología en Escher).

    OpenAIRE

    Montesinos Amilibia, José María

    2010-01-01

    In the late 19th century Fedorov, Schoenflies, and Barlow classified the seventeen wallpaper groups (two-dimensional crystallographic groups, five of them direct movements and twelve of them inverse movements) and the 320 three-dimensional crystallographic groups. In order to get the lists of groups, they all used the same geometric strategy: to combine all possible movements and study them case by case. Later on, Zassenhaus developed a purely algebraic algorithm which allowed him to u...

  19. Internet Based Open Access Crystallographic Databases

    Science.gov (United States)

    Upreti, Girish; Seipel, Bjoern; Harvey, Morgan; Garrick, Will; Moeck, Peter

    2006-05-01

    Two freely accessible crystallographic databases are discussed: the Crystallographic Open Database (COD, http://crystallography.net) which contains over 37,000 crystal structures, and the Nano-Crystallography Database (NCD, http://nanocrystallography.research.pdx.edu) which we recently started to support image-based nanocrystallography and (nano) materials science education. Both databases collect crystallographic relevant information in a standardized format; the Crystallographic Information File (CIF). CIF is the standard file format adopted by the International Union of Crystallography (http://iucr.org) for the archiving and distribution of crystallographic information. A subset of the COD, the Predicted Crystallographic Online Database, allows for 3D structural displays of structural polyhedra and wireframes of approximately 2,600 entries. Since electron microscopist are interested in simple, yet technologically important materials, the crystallographic information for those materials will be included in our database. At our NCD site, entries in the COD and the NCD can be visualized in three dimensions (3D) along with (2D) lattice fringe fingerprints plots. The latter supports the identification of unknown nanocrystal phases from high-resolution transmission electron microscopy (HRTEM) images. Morphological crystal information from the database ``Bestimmungstabellen f"ur Kristalle/ ???????????? ??????????,'' (A.K. Boldyrew and W.W. Doliwo-Dobrowolsky, Zentrales Wissenschaftlichers Institute der Geologie und Sch"urfung, Leningrad/ Moscow, 1937/1939) will also be included in the NCD to support image-based nanocrystallography in 3D.

  20. The New NRL Crystallographic Database

    Science.gov (United States)

    Mehl, Michael; Curtarolo, Stefano; Hicks, David; Toher, Cormac; Levy, Ohad; Hart, Gus

    For many years the Naval Research Laboratory maintained an online graphical database of crystal structures for a wide variety of materials. This database has now been redesigned, updated and integrated with the AFLOW framework for high throughput computational materials discovery (http://materials.duke.edu/aflow.html). For each structure we provide an image showing the atomic positions; the primitive vectors of the lattice and the basis vectors of every atom in the unit cell; the space group and Wyckoff positions; Pearson symbols; common names; and Strukturbericht designations, where available. References for each structure are provided, as well as a Crystallographic Information File (CIF). The database currently includes almost 300 entries and will be continuously updated and expanded. It enables easy search of the various structures based on their underlying symmetries, either by Bravais lattice, Pearson symbol, Strukturbericht designation or commonly used prototypes. The talk will describe the features of the database, and highlight its utility for high throughput computational materials design. Work at NRL is funded by a Contract with the Duke University Department of Mechanical Engineering.

  1. Defining the Crystallographic Fingerprint of Extraterrestrial Treasures

    Science.gov (United States)

    Forman, L. V.; Bland, P. A.; Timms, N. E.; Daly, L.; Benedix, G. K.; Trimby, P. W.

    2016-08-01

    An approach to determine the crystallographic fingerprint of chondritic matrix grains, which is complimentary to the geochemical signature commonly identified to constrain some aspects of the petrogenesis of a sample.

  2. Nexus, crystallographic computing all around the world.

    Science.gov (United States)

    Cranswick, Lachlan Michael David; Bisson, William; Cockcroft, Jeremy Karl

    2008-01-01

    Crystallographic Nexus CD-ROMs, containing a range of free crystallographic software for single-crystal and powder diffraction available on the Internet, have been distributed on request since 1996. The free CD is made in the form of a ;virtual Internet' with the main intent of benefiting crystallographers with inadequate Internet access. The IUCr funds an annual/biennial update which is distributed to known previous recipients. Feedback from current recipients indicates the CD is still useful. The most current IUCr-funded CD is being produced by the CCP14 project at University College London and The Royal Institution UK for distribution to the ECM 2007 and AsCA 2007 conferences.

  3. Non-Crystallographic Symmetry in Packing Spaces

    Directory of Open Access Journals (Sweden)

    Valery G. Rau

    2013-01-01

    Full Text Available In the following, isomorphism of an arbitrary finite group of symmetry, non-crystallographic symmetry (quaternion groups, Pauli matrices groups, and other abstract subgroups, in addition to the permutation group, are considered. Application of finite groups of permutations to the packing space determines space tilings by policubes (polyominoes and forms a structure. Such an approach establishes the computer design of abstract groups of symmetry. Every finite discrete model of the real structure is an element of symmetry groups, including non-crystallographic ones. The set packing spaces of the same order N characterizes discrete deformation transformations of the structure.

  4. Inverse Limits

    CERN Document Server

    Ingram, WT

    2012-01-01

    Inverse limits provide a powerful tool for constructing complicated spaces from simple ones. They also turn the study of a dynamical system consisting of a space and a self-map into a study of a (likely more complicated) space and a self-homeomorphism. In four chapters along with an appendix containing background material the authors develop the theory of inverse limits. The book begins with an introduction through inverse limits on [0,1] before moving to a general treatment of the subject. Special topics in continuum theory complete the book. Although it is not a book on dynamics, the influen

  5. Quantum crystallographic charge density of urea

    Directory of Open Access Journals (Sweden)

    Michael E. Wall

    2016-07-01

    Full Text Available Standard X-ray crystallography methods use free-atom models to calculate mean unit-cell charge densities. Real molecules, however, have shared charge that is not captured accurately using free-atom models. To address this limitation, a charge density model of crystalline urea was calculated using high-level quantum theory and was refined against publicly available ultra-high-resolution experimental Bragg data, including the effects of atomic displacement parameters. The resulting quantum crystallographic model was compared with models obtained using spherical atom or multipole methods. Despite using only the same number of free parameters as the spherical atom model, the agreement of the quantum model with the data is comparable to the multipole model. The static, theoretical crystalline charge density of the quantum model is distinct from the multipole model, indicating the quantum model provides substantially new information. Hydrogen thermal ellipsoids in the quantum model were very similar to those obtained using neutron crystallography, indicating that quantum crystallography can increase the accuracy of the X-ray crystallographic atomic displacement parameters. The results demonstrate the feasibility and benefits of integrating fully periodic quantum charge density calculations into ultra-high-resolution X-ray crystallographic model building and refinement.

  6. Crystallographic theory of the martensitic transformation

    Directory of Open Access Journals (Sweden)

    Edwar A. Torres-López

    2014-08-01

    Full Text Available The martensitic transformation is one of the most researched topics in the materials science during the 20th century. The second half of this century was mainly remembered by the development of several theories related with the kinetics of phase transformation, the mechanisms involved in the nucleation phenomenon, and the way as the crystallographic change is produced. In this paper are described the fundamental concepts that are defined in the crystallographic framework of the martensitic transformation. The study is focused on the application of the most outstanding crystallographic models: the Bain; the Wechsler, Lieberman & Read; and the Bowles & Mackenzie. The topic is presented based upon the particular features of the martensitic transformation, such as its non-diffusional character, type of interface between parent (austenite and product (martensite phases, the formation of substructural defects, and the shape change; all of these features are mathematically described by equations aimed to predict how the transformation will take place rather than to explain the actual movement of the atoms within the structure. This mathematical development is known as the Phenomenological Theory of Martensite Crystallography (PTMC.

  7. A preliminary neutron crystallographic study of thaumatin

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, Susana C. M. [ILL-EMBL Deuteration Laboratory, Partnership for Structural Biology, 6 Rue Jules Horowitz, 38042 Grenoble (France); Institut Laue Langevin, 6 Rue Jules Horowitz, 38042 Grenoble (France); EPSAM and ISTM, Keele University, Staffordshire ST5 5BG (United Kingdom); Blakeley, Matthew P. [Institut Laue Langevin, 6 Rue Jules Horowitz, 38042 Grenoble (France); Leal, Ricardo M. F. [ILL-EMBL Deuteration Laboratory, Partnership for Structural Biology, 6 Rue Jules Horowitz, 38042 Grenoble (France); Institut Laue Langevin, 6 Rue Jules Horowitz, 38042 Grenoble (France); EPSAM and ISTM, Keele University, Staffordshire ST5 5BG (United Kingdom); ESRF, 6 Rue Jules Horowitz, BP-220, 38043 Grenoble (France); Mitchell, Edward P. [EPSAM and ISTM, Keele University, Staffordshire ST5 5BG (United Kingdom); ESRF, 6 Rue Jules Horowitz, BP-220, 38043 Grenoble (France); Forsyth, V. Trevor, E-mail: tforsyth@ill.fr [ILL-EMBL Deuteration Laboratory, Partnership for Structural Biology, 6 Rue Jules Horowitz, 38042 Grenoble (France); Institut Laue Langevin, 6 Rue Jules Horowitz, 38042 Grenoble (France); EPSAM and ISTM, Keele University, Staffordshire ST5 5BG (United Kingdom)

    2008-05-01

    Preliminary neutron crystallographic data from the sweet protein thaumatin have been recorded using the LADI-III diffractometer at the Institut Laue Langevin (ILL). The results illustrate the feasibility of a full neutron structural analysis aimed at further understanding the molecular basis of the perception of sweet taste. Such an analysis will exploit the use of perdeuterated thaumatin. A preliminary neutron crystallographic study of the sweet protein thaumatin is presented. Large hydrogenated crystals were prepared in deuterated crystallization buffer using the gel-acupuncture method. Data were collected to a resolution of 2 Å on the LADI-III diffractometer at the Institut Laue Langevin (ILL). The results demonstrate the feasibility of a full neutron crystallographic analysis of this structure aimed at providing relevant information on the location of H atoms, the distribution of charge on the protein surface and localized water in the structure. This information will be of interest for understanding the specificity of thaumatin–receptor interactions and will contribute to further understanding of the molecular mechanisms underlying the perception of taste.

  8. Quantum crystallographic charge density of urea.

    Science.gov (United States)

    Wall, Michael E

    2016-07-01

    Standard X-ray crystallography methods use free-atom models to calculate mean unit-cell charge densities. Real molecules, however, have shared charge that is not captured accurately using free-atom models. To address this limitation, a charge density model of crystalline urea was calculated using high-level quantum theory and was refined against publicly available ultra-high-resolution experimental Bragg data, including the effects of atomic displacement parameters. The resulting quantum crystallographic model was compared with models obtained using spherical atom or multipole methods. Despite using only the same number of free parameters as the spherical atom model, the agreement of the quantum model with the data is comparable to the multipole model. The static, theoretical crystalline charge density of the quantum model is distinct from the multipole model, indicating the quantum model provides substantially new information. Hydrogen thermal ellipsoids in the quantum model were very similar to those obtained using neutron crystallography, indicating that quantum crystallography can increase the accuracy of the X-ray crystallographic atomic displacement parameters. The results demonstrate the feasibility and benefits of integrating fully periodic quantum charge density calculations into ultra-high-resolution X-ray crystallographic model building and refinement.

  9. Quantum crystallographic charge density of urea

    Science.gov (United States)

    Wall, Michael E.

    2016-01-01

    Standard X-ray crystallography methods use free-atom models to calculate mean unit-cell charge densities. Real molecules, however, have shared charge that is not captured accurately using free-atom models. To address this limitation, a charge density model of crystalline urea was calculated using high-level quantum theory and was refined against publicly available ultra-high-resolution experimental Bragg data, including the effects of atomic displacement parameters. The resulting quantum crystallographic model was compared with models obtained using spherical atom or multipole methods. Despite using only the same number of free parameters as the spherical atom model, the agreement of the quantum model with the data is comparable to the multipole model. The static, theoretical crystalline charge density of the quantum model is distinct from the multipole model, indicating the quantum model provides substantially new information. Hydrogen thermal ellipsoids in the quantum model were very similar to those obtained using neutron crystallography, indicating that quantum crystallography can increase the accuracy of the X-ray crystallographic atomic displacement parameters. The results demonstrate the feasibility and benefits of integrating fully periodic quantum charge density calculations into ultra-high-resolution X-ray crystallographic model building and refinement. PMID:27437111

  10. World directory of crystallographers and of other scientists employing crystallographic methods

    CERN Document Server

    Filippini, G; Hashizume, H; Torriani, I; Duax, W

    1995-01-01

    The 9th edition of the World Directory of Crystallographers and of Other Scientists Employing Crystallographic Methods, which contains 7907 entries embracing 72 countries, differs considerably from the 8th edition, published in 1990. The content has been updated, and the methods used to acquire the information presented and to produce this new edition of the Directory have involved the latest advances in technology. The Directory is now also available as a regularly updated electronic database, accessible via e-mail, Telnet, Gopher, World-Wide Web, and Mosaic. Full details are given in an Appendix to the printed edition.

  11. Inverse disjuncties

    NARCIS (Netherlands)

    Malepaard, J.

    2007-01-01

    Balansschikkingen (of negatief gebonden of-constructies) zijn volgens de in dit artikel ontwikkelde hypothese inverse disjuncties (id's). Het zijn tweeledige zinnen waarvan het eerste lid een verplichte negatieve of minimaliserende constituent bevat en het tweede lid met of begint. Evenals

  12. Crystallographic Analysis of Tapering of ADP Crystallites

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    On the basis of crystallographic characteristics of ADP (ammonium dihydrogen phosphate) crystals and the selected growth conditions, the growth habit of ADP crystals was studied. In comparison with pyramidal planes, the growth rate of prismatic faces is slower and more sensitive to the additives and impurities for ADP crystals. When the supersaturation is low, the advance of growth steps on prismatic face can be blocked by ethanol or impurities, the crystal morphology is changed from the tetragonal prism to shuttle (i.e., the tapered shape). The tapering formation of ADP crystallites was structurally studied in a novel view.

  13. The pros and cons of the inversion method approach to derive 3D dust emission properties of the ISM: the Hi-GAL field centred on (l,b)=(30$^{\\circ}$,0$^{\\circ}$)

    CERN Document Server

    Traficante, Alessio; Compiegne, Mathieu; Alves, Marta I R; Cambresy, Laurent; Gibson, Steven J; Tibbs, Christopher T; Noriega-Crespo, Alberto; Molinari, Sergio; Carey, Sean J; Ingalls, Jim G; Natoli, Paolo; Davies, Rod D; Davis, Richard J; Dickinson, Clive; Fuller, Gary A

    2014-01-01

    Herschel FIR continuum data obtained as part of the Hi-GAL survey have been used, together with the GLIMPSE 8 $\\mu$m and MIPSGAL 24 $\\mu$m data, to attempt the first 3D-decomposition of dust emission associated with atomic, molecular and ionized gas at 15 arcmin angular resolution. Our initial test case is a 2$\\times$2 square degrees region centred on (l,b)=(30$^{\\circ}$,0$^{\\circ}$), a direction that encompasses the origin point of the Scutum-Crux Arm at the tip of the Galactic Bar. Coupling the IR maps with velocity maps specific for different gas phases (HI 21cm, $^{12}$CO and $^{13}$CO, and RRLs), we estimate the properties of dust blended with each of the gas components and at different Galactocentric distances along the LOS. A statistical Pearson's coefficients analysis is used to study the correlation between the column densities and the intensity of the IR emission. This analysis provides evidence that the 2$\\times$2 square degree field under consideration is characterized by the presence of a gas com...

  14. Orbits of crystallographic embedding of non-crystallographic groups and applications to virology.

    Science.gov (United States)

    Twarock, Reidun; Valiunas, Motiejus; Zappa, Emilio

    2015-11-01

    The architecture of infinite structures with non-crystallographic symmetries can be modelled via aperiodic tilings, but a systematic construction method for finite structures with non-crystallographic symmetry at different radial levels is still lacking. This paper presents a group theoretical method for the construction of finite nested point sets with non-crystallographic symmetry. Akin to the construction of quasicrystals, a non-crystallographic group G is embedded into the point group P of a higher-dimensional lattice and the chains of all G-containing subgroups are constructed. The orbits of lattice points under such subgroups are determined, and it is shown that their projection into a lower-dimensional G-invariant subspace consists of nested point sets with G-symmetry at each radial level. The number of different radial levels is bounded by the index of G in the subgroup of P. In the case of icosahedral symmetry, all subgroup chains are determined explicitly and it is illustrated that these point sets in projection provide blueprints that approximate the organization of simple viral capsids, encoding information on the structural organization of capsid proteins and the genomic material collectively, based on two case studies. Contrary to the affine extensions previously introduced, these orbits endow virus architecture with an underlying finite group structure, which lends itself better to the modelling of dynamic properties than its infinite-dimensional counterpart.

  15. Collaborative annotation of 3D crystallographic models.

    Science.gov (United States)

    Hunter, J; Henderson, M; Khan, I

    2007-01-01

    This paper describes the AnnoCryst system-a tool that was designed to enable authenticated collaborators to share online discussions about 3D crystallographic structures through the asynchronous attachment, storage, and retrieval of annotations. Annotations are personal comments, interpretations, questions, assessments, or references that can be attached to files, data, digital objects, or Web pages. The AnnoCryst system enables annotations to be attached to 3D crystallographic models retrieved from either private local repositories (e.g., Fedora) or public online databases (e.g., Protein Data Bank or Inorganic Crystal Structure Database) via a Web browser. The system uses the Jmol plugin for viewing and manipulating the 3D crystal structures but extends Jmol by providing an additional interface through which annotations can be created, attached, stored, searched, browsed, and retrieved. The annotations are stored on a standardized Web annotation server (Annotea), which has been extended to support 3D macromolecular structures. Finally, the system is embedded within a security framework that is capable of authenticating users and restricting access only to trusted colleagues.

  16. X-ray crystallographic studies of metalloproteins.

    Science.gov (United States)

    Volbeda, Anne

    2014-01-01

    Many proteins require metals for their physiological function. In combination with spectroscopic characterizations, X-ray crystallography is a very powerful method to correlate the function of protein-bound metal sites with their structure. Due to their special X-ray scattering properties, specific metals may be located in metalloprotein structures and eventually used for phasing the diffracted X-rays by the method of Multi-wavelength Anomalous Dispersion (MAD). How this is done is the principle subject of this chapter. Attention is also given to the crystallographic characterization of different oxidation states of redox active metals and to the complication of structural changes that may be induced by X-ray irradiation of protein crystals.

  17. The effect of crystallographic texture on stress-induced martensitic transformation in NiTi: A computational analysis.

    Science.gov (United States)

    Weafer, F M; Guo, Y; Bruzzi, M S

    2016-01-01

    NiTi׳s superelasticity is exploited in a number of biomedical devices, in particular self-expanding endovascular stents. These stents are often laser-cut from textured micro-tubing; texture is the distribution of crystallographic grain orientations in a polycrystalline material which has been experimentally shown to have a marked influence on mechanical properties. This study offers a computational examination into the effect of texture on the stress-induced martensite transformation (SIMT) in a micro-dogbone NiTi specimen subject to tensile loading. Finite Element Analysis (FEA) is employed to simulate the transformational behaviour of the specimen on a micro-scale level. To represent a realistic grain structure in the FEA model, grains present in a 200µm×290µm test site located at the centre edge of the specimen were identified using Scanning Electron Microscopy (SEM). Grains are assumed to have homogenous behaviour with properties varying according to their crystallographic orientation to the loading direction. Required material properties were extracted from uniaxial stress-strain curves of single crystals for each crystallographic orientation for input into the in-built UMAT/Nitinol. The orientation of each grain in the test site was identified using Electron Back-Scatter Diffraction (EBSD) techniques. In this way, a quantitative explanation is offered to the effect of crystallographic texture on SIMT. Finally, the evolution of grains in the specimen, during the transformation process, was experimentally investigated by means of an in-situ SEM tensile test.

  18. CMS Centre at CERN

    CERN Multimedia

    2007-01-01

    A new "CMS Centre" is being established on the CERN Meyrin site by the CMS collaboration. It will be a focal point for communications, where physicists will work together on data quality monitoring, detector calibration, offline analysis of physics events, and CMS computing operations. Construction of the CMS Centre begins in the historic Proton Synchrotron (PS) control room. The historic Proton Synchrotron (PS) control room, Opened by Niels Bohr in 1960, will be reused by CMS to built its control centre. TThe LHC@FNAL Centre, in operation at Fermilab in the US, will work very closely with the CMS Centre, as well as the CERN Control Centre. (Photo Fermilab)The historic Proton Synchrotron (PS) control room is about to start a new life. Opened by Niels Bohr in 1960, the room will be reused by CMS to built its control centre. When finished, it will resemble the CERN Contro...

  19. Crystallographic orientation dependent etching of graphene layers

    Energy Technology Data Exchange (ETDEWEB)

    Nemes-Incze, Peter; Biro, Laszlo Peter [Research Institute for Technical Physics and Materials Science, PO. Box 49, 1525 Budapest (Hungary); Magda, Gabor [Budapest University of Technology and Economics (BME), PO Box 91, 1521 Budapest (Hungary); Kamaras, Katalin [Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, PO Box 49, 1525, Budapest (Hungary)

    2010-04-15

    Graphene has gripped the scientific community ever since its discovery in 2004, with very promising electronic properties and hopes to integrate graphene into nanoelectronic devices. For graphene to make its way into electronic devices, two major obstacles have to be overcome: reproducible preparation of large area graphene samples and patterning techniques to obtain functional components. In this paper we present a graphene etching technique, which is crystallographic orientation selective and allows for the patterning of graphene layers using a chemical reduction process. The process involves the reduction of the SiO{sub 2} support by the carbon in the graphene itself. This reaction only occurs at the sample edges and does not result in the degradation of the graphene crystal lattice itself. However, we have observed evidence of strong hole doping in our etched samples. This etching technique opens up new possibilities in graphene patterning and modification. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Determination of crystallographic intensities from sparse data

    Directory of Open Access Journals (Sweden)

    Kartik Ayyer

    2015-01-01

    Full Text Available X-ray serial microcrystallography involves the collection and merging of frames of diffraction data from randomly oriented protein microcrystals. The number of diffracted X-rays in each frame is limited by radiation damage, and this number decreases with crystal size. The data in the frame are said to be sparse if too few X-rays are collected to determine the orientation of the microcrystal. It is commonly assumed that sparse crystal diffraction frames cannot be merged, thereby setting a lower limit to the size of microcrystals that may be merged with a given source fluence. The EMC algorithm [Loh & Elser (2009, Phys. Rev. E, 80, 026705] has previously been applied to reconstruct structures from sparse noncrystalline data of objects with unknown orientations [Philipp et al. (2012, Opt. Express, 20, 13129–13137; Ayyer et al. (2014, Opt. Express, 22, 2403–2413]. Here, it is shown that sparse data which cannot be oriented on a per-frame basis can be used effectively as crystallographic data. As a proof-of-principle, reconstruction of the three-dimensional diffraction intensity using sparse data frames from a 1.35 kDa molecule crystal is demonstrated. The results suggest that serial microcrystallography is, in principle, not limited by the fluence of the X-ray source, and collection of complete data sets should be feasible at, for instance, storage-ring X-ray sources.

  1. Topological inverse semigroups

    Institute of Scientific and Technical Information of China (English)

    ZHU Yongwen

    2004-01-01

    That the projective limit of any projective system of compact inverse semigroups is also a compact inverse semigroup,the injective limit of any injective system of inverse semigroups is also an inverse semigroup, and that a compact inverse semigroup is topologically isomorphic to a strict projective limit of compact metric inverse semigroups are proved. It is also demonstrated that Horn (S,T) is a topological inverse semigroup provided that S or T is a topological inverse semigroup with some other conditions. Being proved by means of the combination of topological semigroup theory with inverse semigroup theory,all these results generalize the corresponding ones related to topological semigroups or topological groups.

  2. Crystallographic interpretation of Galois symmetries for magnetic pentagonal ring

    Science.gov (United States)

    Milewski, J.; Lulek, T.; Łabuz, M.

    2017-03-01

    Galois symmetry of exact Bethe Ansatz eigenstates for the magnetic pentagonal ring within the XXX model are investigated by a comparison with crystallographic constructions of space groups. It follows that the arithmetic symmetry of Bethe parameters for the interior of the Brillouin zone admits crystallographic interpretation, in terms of the periodic square Z2 ×Z2 , that is the two-dimensional crystal lattice with Born-Karman period two in both directions.

  3. Client Centred Desing

    DEFF Research Database (Denmark)

    Ørngreen, Rikke; Nielsen, Janni; Levinsen, Karin

    2008-01-01

    In this paper we argue for the use of Client Centred preparation phases when designing complex systems. Through Client Centred Design human computer interaction can extend the focus on end-users to alse encompass the client's needs, context and resources....

  4. Crystallographic and magnetic structures of Pr6Fe13Ge studied by powder neutron diffraction

    Institute of Scientific and Technical Information of China (English)

    Wang Fang-Wei; Zhang Pan-Lin; Shen Bao-Gen; Yan Qi-Wei

    2004-01-01

    Crystallographic and magnetic structures of Pr6Fel3Ge have been investigated by high-resolution powder neutron diffraction in the temperature range of 10-300 K. The magnetic structure consists of ferromagnetic Pr6Fe13 slabs that alternate antiferromagnetically, along c, with the next Pr6Fe13 slab separated by a non-magnetic Ge layer. The magnetic moments lie within the ab-planes. The propagation vector of this structure is k=(001) with respect to the conventional reciprocal lattice of the Ⅰ-centred structure. However, the temperature-dependence of neutron-scattering intensity of the (110) Bragg peak, very similar to the temperature-dependent magnetization measured by SQUID magnetometer,indicates that a small c-axis ferromagnetic component should be added to the above antiferromagnetic model.

  5. Crystallization and crystallographic studies of kallistatin

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Fang; Zhou, Aiwu; Wei, Zhenquan, E-mail: weizhq@gmail.com [Shanghai Jiaotong University School of Medicine (Room 1006, Building 2, No 280, South Chongqing Road), Shanghai 200025, People’s Republic of (China)

    2015-08-25

    The crystallization of human kallistatin in the relaxed conformation is reported. Kallistatin is a serine protease inhibitor (serpin) which specifically inhibits human tissue kallikrein; however, its inhibitory activity is inhibited by heparin. In order to elucidate the underlying mechanism, recombinant human kallistatin was prepared in Escherichia coli and the protein was crystallized by the sitting-drop vapour-diffusion method. X-ray diffraction data were collected to 1.9 Å resolution. The crystals were found to belong to space group P6{sub 1}, with unit-cell parameters a = 113.51, b = 113.51, c = 76.17 Å. Initial analysis indicated that the crystallized kallistatin was in a relaxed conformation, with its reactive-centre loop inserted in the central β-sheet.

  6. Maximum a posteriori estimation of crystallographic phases in X-ray diffraction tomography

    Energy Technology Data Exchange (ETDEWEB)

    Gürsoy, Doǧa; Bicer, Tekin; Almer, Jonathan D.; Kettimuthu, Rajkumar; Stock, Stuart; De Carlo, Francesco

    2015-06-13

    A maximum a posteriori approach is proposed for X-ray diffraction tomography for reconstructing three-dimensional spatial distribution of crystallographic phases and orientations of polycrystalline materials. The approach maximizes the a posteriori density which includes a Poisson log-likelihood and an a priori term that reinforces expected solution properties such as smoothness or local continuity. The reconstruction method is validated with experimental data acquired from a section of the spinous process of a porcine vertebra collected at the 1-ID-C beamline of the Advanced Photon Source, at Argonne National Laboratory. The reconstruction results show significant improvement in the reduction of aliasing and streaking artefacts, and improved robustness to noise and undersampling compared to conventional analytical inversion approaches. The approach has the potential to reduce data acquisition times, and significantly improve beamtime efficiency.

  7. Virtual particle therapy centre

    CERN Multimedia

    2015-01-01

    Particle therapy is an advanced technique of cancer radiation therapy, using protons or other ions to target the cancerous mass. This advanced technique requires a multi-disciplinary team working in a specialised centre. 3D animation: Nymus3D

  8. The IGU Knowledge Centre

    NARCIS (Netherlands)

    Huizing, Bernardus

    2005-01-01

    This article describes an innovative service for members of the International Gas Union - IGU. The IGU Knowledge Centre provides members with relevant information and data. In this article is described why, how and where.

  9. CENTRE FOR GEOMETRICAL METROLOGY

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo

    The objective of this Annual Report is to give a general introduction to CGM as well as to give an account of the tasks carried out using the facilities of CGM's Instrument Centre during 1998 and 1999....

  10. Crystallographic effects during micromachining — A finite-element model

    Science.gov (United States)

    Song, Shin-Hyung; Choi, Woo Chun

    2015-07-01

    Mechanical micromachining is a powerful and effective way for manufacturing small sized machine parts. Even though the micromachining process is similar to the traditional machining, the material behavior during the process is much different. In particular, many researchers report that the basic mechanics of the work material is affected by microstructures and their crystallographic orientations. For example, crystallographic orientations of the work material have significant influence on force response, chip formation and surface finish. In order to thoroughly understand the effect of crystallographic orientations on the micromachining process, finite-element model (FEM) simulating orthogonal cutting process of single crystallographic material was presented. For modeling the work material, rate sensitive single crystal plasticity of face-centered cubic (FCC) crystal was implemented. For the chip formation during the simulation, element deletion technique was used. The simulation model is developed using ABAQUS/explicit with user material subroutine via user material subroutine (VUMAT). Simulations showed that variation of the specific cutting energy at different crystallographic orientations of work material shows significant anisotropy. The developed FEM model can be a useful prediction tool of micromachining of crystalline materials.

  11. Crystallographic orientation and concentric layers in spicules of calcareous sponges.

    Science.gov (United States)

    Rossi, André Linhares; Ribeiro, Bárbara; Lemos, Moara; Werckmann, Jacques; Borojevic, Radovan; Fromont, Jane; Klautau, Michelle; Farina, Marcos

    2016-11-01

    In this work, the crystallography of calcareous sponges (Porifera) spicules and the organization pattern of the concentric layers present in their inner structure were investigated in 10 species of the subclass Calcaronea and three species of the subclass Calcinea. Polished spicules had specific concentric patterns that varied depending on the plane in which the spicules were sectioned. A 3D model of the concentric layers was created to interpret these patterns and the biomineralization process of the triactine spicules. The morphology of the spicules was compared with the crystallographic orientation of the calcite crystals by analyzing the Kikuchi diffraction patterns using a scanning electron microscope. Triactine spicules from the subclass Calcinea had actines (rays) elongated in the 〈210〉 direction, which is perpendicular to the c-axis. The scale spicules of the hypercalcified species Murrayona phanolepis presented the c-axis perpendicular to the plane of the scale, which is in accordance with the crystallography of all other Calcinea. The triactine spicules of the calcaronean species had approximately the same crystallographic orientation with the unpaired actine elongated in the ∼[211] direction. Only one Calcaronea species, whose triactine was regular, had a different orientation. Three different crystallographic orientations were found in diactines. Spicules with different morphologies, dimensions and positions in the sponge body had similar crystallographic directions suggesting that the crystallographic orientation of spicules in calcareous sponges is conserved through evolution. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Locally Inverse Semigroups with Inverse Transversals

    Institute of Scientific and Technical Information of China (English)

    SHAO Yong; ZHAO Xian Zhong

    2009-01-01

    Let S be a locally inverse semigroup with an inverse transversal S°. In this paper, we construct an amenable partial order on S by an R-cone. Conversely, every amenable partial order on S can be constructed in this way. We give some properties of a locally inverse semigroup with a Clifford transversal. In particular, if S is a locally inverse semigroup with a Clifford transversal, then there is an order-preserving bijection from the set of all amenable partial orders on S to the set of all R-cones of S.

  13. Crystallographic Topology 2: Overview and Work in Progress

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, C.K.

    1999-08-01

    This overview describes an application of contemporary geometric topology and stochastic process concepts to structural crystallography. In this application, crystallographic groups become orbifolds, crystal structures become Morse functions on orbifolds, and vibrating atoms in a crystal become vector valued Gaussian measures with the Radon-Nikodym property. Intended crystallographic benefits include new methods for visualization of space groups and crystal structures, analysis of the thermal motion patterns seen in ORTEP drawings, and a classification scheme for crystal structures based on their Heegaard splitting properties.

  14. Crystal structure refinement a crystallographers guide to SHELXL

    CERN Document Server

    2006-01-01

    A crystallographers guide to SHELXL, covering various aspects of practical crystal structure refinement, from the treatment of hydrogen atoms to the assignment of atom types, and more. After an introduction to SHELXL, a brief survey of crystal structure refinement is provided.

  15. Recovery of crystallographic texture in remineralized dental enamel.

    Science.gov (United States)

    Siddiqui, Samera; Anderson, Paul; Al-Jawad, Maisoon

    2014-01-01

    Dental caries is the most prevalent disease encountered by people of all ages around the world. Chemical changes occurring in the oral environment during the caries process alter the crystallography and microstructure of dental enamel resulting in loss of mechanical function. Little is known about the crystallographic effects of demineralization and remineralization. The motivation for this study was to develop understanding of the caries process at the crystallographic level in order to contribute towards a long term solution. In this study synchrotron X-ray diffraction combined with scanning electron microscopy and scanning microradiography have been used to correlate enamel crystallography, microstructure and mineral concentration respectively in enamel affected by natural caries and following artificial demineralization and remineralization regimes. In particular, the extent of destruction and re-formation of this complex structure has been measured. 2D diffraction patterns collected at the European Synchrotron Radiation Facility were used to quantify changes in the preferred orientation (crystallographic texture) and position of the (002) Bragg reflection within selected regions of interest in each tooth slice, and then correlated with the microstructure and local mineral mass. The results revealed that caries and artificial demineralization cause a large reduction in crystallographic texture which is coupled with the loss of mineral mass. Remineralization restores the texture to the original level seen in healthy enamel and restores mineral density. The results also showed that remineralization promotes ordered formation of new crystallites and growth of pre-existing crystallites which match the preferred orientation of healthy enamel. Combining microstructural and crystallographic characterization aids the understanding of caries and erosion processes and assists in the progress towards developing therapeutic treatments to allow affected enamel to regain

  16. Crystallographic Mapping of Guided Nanowires by Second Harmonic Generation Polarimetry.

    Science.gov (United States)

    Neeman, Lior; Ben-Zvi, Regev; Rechav, Katya; Popovitz-Biro, Ronit; Oron, Dan; Joselevich, Ernesto

    2017-02-08

    The growth of horizontal nanowires (NWs) guided by epitaxial and graphoepitaxial relations with the substrate is becoming increasingly attractive owing to the possibility of controlling their position, direction, and crystallographic orientation. In guided NWs, as opposed to the extensively characterized vertically grown NWs, there is an increasing need for understanding the relation between structure and properties, specifically the role of the epitaxial relation with the substrate. Furthermore, the uniformity of crystallographic orientation along guided NWs and over the substrate has yet to be checked. Here we perform highly sensitive second harmonic generation (SHG) polarimetry of polar and nonpolar guided ZnO NWs grown on R-plane and M-plane sapphire. We optically map large areas on the substrate in a nondestructive way and find that the crystallographic orientations of the guided NWs are highly selective and specific for each growth direction with respect to the substrate lattice. In addition, we perform SHG polarimetry along individual NWs and find that the crystallographic orientation is preserved along the NW in both polar and nonpolar NWs. While polar NWs show highly uniform SHG along their axis, nonpolar NWs show a significant change in the local nonlinear susceptibility along a few micrometers, reflected in a reduction of 40% in the ratio of the SHG along different crystal axes. We suggest that these differences may be related to strain accumulation along the nonpolar wires. We find SHG polarimetry to be a powerful tool to study both selectivity and uniformity of crystallographic orientations of guided NWs with different epitaxial relations.

  17. Recovery of crystallographic texture in remineralized dental enamel.

    Directory of Open Access Journals (Sweden)

    Samera Siddiqui

    Full Text Available Dental caries is the most prevalent disease encountered by people of all ages around the world. Chemical changes occurring in the oral environment during the caries process alter the crystallography and microstructure of dental enamel resulting in loss of mechanical function. Little is known about the crystallographic effects of demineralization and remineralization. The motivation for this study was to develop understanding of the caries process at the crystallographic level in order to contribute towards a long term solution. In this study synchrotron X-ray diffraction combined with scanning electron microscopy and scanning microradiography have been used to correlate enamel crystallography, microstructure and mineral concentration respectively in enamel affected by natural caries and following artificial demineralization and remineralization regimes. In particular, the extent of destruction and re-formation of this complex structure has been measured. 2D diffraction patterns collected at the European Synchrotron Radiation Facility were used to quantify changes in the preferred orientation (crystallographic texture and position of the (002 Bragg reflection within selected regions of interest in each tooth slice, and then correlated with the microstructure and local mineral mass. The results revealed that caries and artificial demineralization cause a large reduction in crystallographic texture which is coupled with the loss of mineral mass. Remineralization restores the texture to the original level seen in healthy enamel and restores mineral density. The results also showed that remineralization promotes ordered formation of new crystallites and growth of pre-existing crystallites which match the preferred orientation of healthy enamel. Combining microstructural and crystallographic characterization aids the understanding of caries and erosion processes and assists in the progress towards developing therapeutic treatments to allow affected

  18. Academic Drug Discovery Centres

    DEFF Research Database (Denmark)

    Kirkegaard, Henriette Schultz; Valentin, Finn

    2014-01-01

    Academic drug discovery centres (ADDCs) are seen as one of the solutions to fill the innovation gap in early drug discovery, which has proven challenging for previous organisational models. Prior studies of ADDCs have identified the need to analyse them from the angle of their economic...... their performance....

  19. CENTRE IN NIGERIA.

    African Journals Online (AJOL)

    PATTERN OF NEURO-OPHTHALMIC DISORDERS IN A TERTIARY EYE. CENTRE IN NIGERIA. A E Omoti , M J M ... movement or light was determined. The external ... assessed by color desaturation tests and visual field assessment by the ...

  20. Implementing Responsibility Centre Budgeting

    Science.gov (United States)

    Vonasek, Joseph

    2011-01-01

    Recently, institutes of higher education (universities) have shown a renewed interest in organisational structures and operating methodologies that generate productivity and innovation; responsibility centre budgeting (RCB) is one such process. This paper describes the underlying principles constituting RCB, its origin and structural elements, and…

  1. The GSO Data Centre

    CERN Document Server

    Paletou, F; Génot, V; Rouillard, A; Petit, P; Palacios, A; Caux, E; Wakelam, V

    2015-01-01

    Hereafter we describe the activities of the $Grand \\, Sud-Ouest$ Data Centre operated for INSU/CNRS by the OMP-IRAP and the Universit\\'e Paul Sabatier (Toulouse), in a collaboration with the OASU-LAB (Bordeaux) and OREME-LUPM (Montpellier).

  2. Implementing Responsibility Centre Budgeting

    Science.gov (United States)

    Vonasek, Joseph

    2011-01-01

    Recently, institutes of higher education (universities) have shown a renewed interest in organisational structures and operating methodologies that generate productivity and innovation; responsibility centre budgeting (RCB) is one such process. This paper describes the underlying principles constituting RCB, its origin and structural elements, and…

  3. ATLAS Visitors Centre

    CERN Multimedia

    claudia Marcelloni

    2009-01-01

    ATLAS Visitors Centre has opened its shiny new doors to the public. Officially launched on Monday February 23rd, 2009, the permanent exhibition at Point 1 was conceived as a tour resource for ATLAS guides, and as a way to preserve the public’s opportunity to get a close-up look at the experiment in action when the cavern is sealed.

  4. Inverse anticipating chaos synchronization.

    Science.gov (United States)

    Shahverdiev, E M; Sivaprakasam, S; Shore, K A

    2002-07-01

    We derive conditions for achieving inverse anticipating synchronization where a driven time-delay chaotic system synchronizes to the inverse future state of the driver. The significance of inverse anticipating chaos in delineating synchronization regimes in time-delay systems is elucidated. The concept is extended to cascaded time-delay systems.

  5. Locative Inversion in Cantonese.

    Science.gov (United States)

    Mok, Sui-Sang

    This study investigates the phenomenon of "Locative Inversion" in Cantonese. The term "Locative Inversion" indicates that the locative phrase (LP) syntactic process in Cantonese and the appears at the sentence-initial position and its logical subject occurs postverbally. It is demonstrated that this Locative Inversion is a…

  6. Transfer of olivine crystallographic orientation through a cycle of serpentinisation and dehydration

    Science.gov (United States)

    Dunkel, Kristina G.; Austrheim, Håkon; Ildefonse, Benoit; Jamtveit, Bjørn

    2017-08-01

    Our ability to decipher the mechanisms behind metamorphic transformation processes depends in a major way on the extent to which crystallographic and microstructural information is transferred from one stage to another. Within the Leka Ophiolite Complex in the Central Norwegian Caledonides, prograde olivine veins that formed by dehydration of serpentinite veins in dunites exhibit a characteristic distribution of microstructures: The outer part of the veins comprises coarse-grained olivine that forms an unusual, brick-like microstructure. The inner part of the veins, surrounding a central fault, is composed of fine-grained olivine. Where the fault movement included a dilational component, optically clear, equant olivine occurs in the centre. Electron backscatter diffraction mapping reveals that the vein olivine has inherited its crystallographic preferred orientation (CPO) from the olivine in the porphyroclastic host rock; however, misorientation is weaker and associated to different rotation axes. We propose that prograde olivine grew epitaxially on relics of mantle olivine and thereby acquired its CPO. Growth towards pre-existing microfractures along which serpentinisation had occurred led to straight grain boundaries and a brick-like microstructure in the veins. When dehydration embrittlement induced slip, a strong strain localisation on discrete fault planes prevented distortion of the CPO due to cataclastic deformation; grain size reduction did not significantly modify the olivine CPO. This illustrates how a CPO can be preserved though an entire metamorphic cycle, including hydration, dehydration, and deformation processes, and that the CPO and the microstructures (e.g. grain shape) of one phase do not necessarily record the same event.

  7. Reorientation of M{sub A}{sup +}-centres in CaF{sub 2}:Me{sup +} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Chornyi, Z.P.; Shchur, G.O.; Salapak, V.M. [Ukrainian State Univ. of Forestry and Wood Technology, Lviv (Ukraine); Kravchuk, I.M.; Kachan, S.I. [State Univ. ' ' Lvivska Polytekhnika' ' , Lviv (Ukraine)

    2001-02-01

    Studies of photoinductive dichroism allow to define the orientation of colour centres. The photo-inductive dichroism of absorption testifies the fact that oscillators, responsible for the long-wave absorption band of M{sub A}{sup +}-centres, are located along left angle 100 right angle crystallographic directions, and high-energetic oscillators, along left angle 110 right angle crystallographic directions. Various impurities cause unequal perturbations in the crystal lattice. The determination of the kinetic parameters of the reorientation processes in simple and complex colour centres allows establishing the structure of the aggregative centre. The size of the impurity ion influences the energy of reorientation of M{sub A}{sup +}-centres, and this, in turn, is connected with the displacement of vacancies towards the anion sites of the crystal. It is found that the anion vacancy in M{sub A}{sup +}-centres jumps in left angle 110 right angle directions, but in F{sub A}{sup +}-centres it jumps in left angle 100 right angle directions. (orig.)

  8. Town Centre Redevelopment Strategies

    DEFF Research Database (Denmark)

    Vagnby, Bo Hellisen

    as slum clearence and urban renewal. To a certain extent parallels are drawn to international experiences, especially where these are of such a nature that they can be assumed transferred to Danish connctions. Conclusively, the strategies are discussed in the light of the turn of Danish urban planning...... urban planning and design strategieswhich have been practised in most of the larger Danish towns: pedestrian streets, shopping centres, preservation of historic features, waterfronts, concentration of offices, conference and sports facilities, improvement og traffic and transport conditions as well...... during late years, where increased internationalisation is in focus and where it seems as if the social dimension of the town centre planning is slipping out of the hands of the urban planners....

  9. Elderly Care Centre

    Science.gov (United States)

    Wagiman, Aliani; Haja Bava Mohidin, Hazrina; Ismail, Alice Sabrina

    2016-02-01

    The demand for elderly centre has increased tremendously abreast with the world demographic change as the number of senior citizens rose in the 21st century. This has become one of the most crucial problems of today's era. As the world progress into modernity, more and more people are occupied with daily work causing the senior citizens to lose the care that they actually need. This paper seeks to elucidate the best possible design of an elderly care centre with new approach in order to provide the best service for them by analysing their needs and suitable activities that could elevate their quality of life. All these findings will then be incorporated into design solutions so as to enhance the living environment for the elderly especially in Malaysian context.

  10. Call centres: constructing flexibility

    OpenAIRE

    Arzbächer, Sandra; Holtgrewe, Ursula; Kerst, Christian

    2002-01-01

    "The development of call centres as a flexible interface between firms and their environments has been seen as exemplary or even symptomatic of flexible capitalism (Sennett 1998). We are going to point out that they do not just stand for organisational change but also for changes of institutions towards deregulation. Employers and managers hoped for gains of flexibility, decreasing labour costs, and market gains by an expanded 24-hour-service. Surveillance and control by flexib...

  11. Historical centres: changing definitions

    Directory of Open Access Journals (Sweden)

    Roberta Lazzarotti

    2014-02-01

    Full Text Available Since the end of the Second World War, the architectural and planning culture has been showing a fluctuating attention to the theme of historical centres and their enhancement. First of all this uneven progress explains the difficulty to reach a homogeneous definition and this is still lacking. During a long phase of this period, the historical parts of the town were considered as objects to be preserved in an integral way, as urban monuments. This is mostly due to the high symbolic value of these settlements, that represent fundamental landmarks. Identity building and empowerment of local communities are indispensable conditions for any development programme, especially in the case of centres or other historic environments at risk of abandonment. The progressive evolution of this concept brings awareness of the impossibility of separating – either in analytical or in planning terms ­ historical centres from their urban and territorial contexts, which are linked by mutual, deep relationships. This article attempts to retrace the steps signaled by the publication of international documents and conventions, from the Charter of Gubbio (1960 to the Charter of Krakow and the European Landscape Convention (2000; they obviously represent particular points of view, not exhaustive of the richness of the positions in the debate, but extremely significant in terms of diffusion and consensus.

  12. Crystallographic data processing for free-electron laser sources

    Energy Technology Data Exchange (ETDEWEB)

    White, Thomas A., E-mail: taw@physics.org; Barty, Anton; Stellato, Francesco [DESY, Notkestrasse 85, 22607 Hamburg (Germany); Holton, James M. [University of California, San Francisco, CA 94158 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Kirian, Richard A. [DESY, Notkestrasse 85, 22607 Hamburg (Germany); Arizona State University, Tempe, AZ 85287 (United States); Zatsepin, Nadia A. [Arizona State University, Tempe, AZ 85287 (United States); Chapman, Henry N. [DESY, Notkestrasse 85, 22607 Hamburg (Germany); University of Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany)

    2013-07-01

    A processing pipeline for diffraction data acquired using the ‘serial crystallography’ methodology with a free-electron laser source is described with reference to the crystallographic analysis suite CrystFEL and the pre-processing program Cheetah. A processing pipeline for diffraction data acquired using the ‘serial crystallography’ methodology with a free-electron laser source is described with reference to the crystallographic analysis suite CrystFEL and the pre-processing program Cheetah. A detailed analysis of the nature and impact of indexing ambiguities is presented. Simulations of the Monte Carlo integration scheme, which accounts for the partially recorded nature of the diffraction intensities, are presented and show that the integration of partial reflections could be made to converge more quickly if the bandwidth of the X-rays were to be increased by a small amount or if a slight convergence angle were introduced into the incident beam.

  13. Crystallographic changes in lead zirconate titanate due to neutron irradiation

    Directory of Open Access Journals (Sweden)

    Alexandra Henriques

    2014-11-01

    Full Text Available Piezoelectric and ferroelectric materials are useful as the active element in non-destructive monitoring devices for high-radiation areas. Here, crystallographic structural refinement (i.e., the Rietveld method is used to quantify the type and extent of structural changes in PbZr0.5Ti0.5O3 after exposure to a 1 MeV equivalent neutron fluence of 1.7 × 1015 neutrons/cm2. The results show a measurable decrease in the occupancy of Pb and O due to irradiation, with O vacancies in the tetragonal phase being created preferentially on one of the two O sites. The results demonstrate a method by which the effects of radiation on crystallographic structure may be investigated.

  14. Recent developments in crystallographic investigation of martensitic transformation

    Institute of Scientific and Technical Information of China (English)

    GU Nanju; DONG Guixia; LIN Xiaoping; WANG Baoqi; MA Xiaoli

    2004-01-01

    The results and new knowledge obtained in recent years by using an atom force microscope (AFM) to investigate the surface relieves and to reveal the lattice deformation characteristics in martensitic transformation (MT) are summarized. All-round analysis and research about crystallography and morphology of MT have been done based on our "displacement vector" theory. New viewpoints that the "invariant-plane-strain" criterion have no universality and that the large rotation of habit-planes takes place in {557} lath and {225} plate martensites are put forward. Thereby, the formation mode of {557} martensite is established, which is in good agreement with the experimental results. Finally, according to the self-accommodation principle between variants crystallographic calculations of twin and multi-variant martensites in shape memory alloys have been carried out. The calculation method greatly simplifies the crystallographic calculation process of phenomenological theory. And the calculated results are in good agreement with experimental ones.

  15. Tele-centres in Ghana

    DEFF Research Database (Denmark)

    Falch, Morten

    2004-01-01

    Tele-centres offer a low cost opportunity for the many who cannot afford their own phone or Internet connection. This paper presents a field study of tele-centres in Ghana and analyses how they contribute to universal access.......Tele-centres offer a low cost opportunity for the many who cannot afford their own phone or Internet connection. This paper presents a field study of tele-centres in Ghana and analyses how they contribute to universal access....

  16. Crystallographically uniform arrays of ordered (In)GaN nanocolumns

    Energy Technology Data Exchange (ETDEWEB)

    Gačević, Ž., E-mail: gacevic@isom.upm.es; Bengoechea-Encabo, A.; Albert, S.; Calleja, E. [ETSIT-ISOM, Universidad Politécnica de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain); Torres-Pardo, A.; González-Calbet, J. M. [Dept. Química Inorgánica, Universidad Complutense, 28040 Madrid (Spain); CEI Campus Moncloa, UCM-UPM, Madrid (Spain)

    2015-01-21

    In this work, through a comparative study of self-assembled (SA) and selective area grown (SAG) (In)GaN nanocolumn (NC) ensembles, we first give a detailed insight into improved crystallographic uniformity (homogeneity of crystallographic tilts and twists) of the latter ones. The study, performed making use of: reflective high energy electron diffraction, X-ray diffraction and scanning electron microscopy, reveals that unlike their SA counterparts, the ensembles of SAG NCs show single epitaxial relationship to both sapphire(0001) and Si(111) underlying substrates. In the second part of the article, making use of X-ray diffraction, we directly show that the selective area growth leads to improved compositional uniformity of InGaN NC ensembles. This further leads to improved spectral purity of their luminescence, as confirmed by comparative macro-photoluminescence measurements performed on SA and SAG InGaN NC ensembles. An improved crystallographic uniformity of NC ensembles facilitates their integration into optoelectronic devices, whereas their improved compositional uniformity allows for their employment in single-color optoelectronic applications.

  17. Crystallographically uniform arrays of ordered (In)GaN nanocolumns

    Science.gov (United States)

    Gačević, Ž.; Bengoechea-Encabo, A.; Albert, S.; Torres-Pardo, A.; González-Calbet, J. M.; Calleja, E.

    2015-01-01

    In this work, through a comparative study of self-assembled (SA) and selective area grown (SAG) (In)GaN nanocolumn (NC) ensembles, we first give a detailed insight into improved crystallographic uniformity (homogeneity of crystallographic tilts and twists) of the latter ones. The study, performed making use of: reflective high energy electron diffraction, X-ray diffraction and scanning electron microscopy, reveals that unlike their SA counterparts, the ensembles of SAG NCs show single epitaxial relationship to both sapphire(0001) and Si(111) underlying substrates. In the second part of the article, making use of X-ray diffraction, we directly show that the selective area growth leads to improved compositional uniformity of InGaN NC ensembles. This further leads to improved spectral purity of their luminescence, as confirmed by comparative macro-photoluminescence measurements performed on SA and SAG InGaN NC ensembles. An improved crystallographic uniformity of NC ensembles facilitates their integration into optoelectronic devices, whereas their improved compositional uniformity allows for their employment in single-color optoelectronic applications.

  18. Direct Waveform Inversion by Iterative Inverse Propagation

    CERN Document Server

    Schlottmann, R B

    2009-01-01

    Seismic waves are the most sensitive probe of the Earth's interior we have. With the dense data sets available in exploration, images of subsurface structures can be obtained through processes such as migration. Unfortunately, relating these surface recordings to actual Earth properties is non-trivial. Tomographic techniques use only a small amount of the information contained in the full seismogram and result in relatively low resolution images. Other methods use a larger amount of the seismogram but are based on either linearization of the problem, an expensive statistical search over a limited range of models, or both. We present the development of a new approach to full waveform inversion, i.e., inversion which uses the complete seismogram. This new method, which falls under the general category of inverse scattering, is based on a highly non-linear Fredholm integral equation relating the Earth structure to itself and to the recorded seismograms. An iterative solution to this equation is proposed. The res...

  19. Inverse Kinematics using Quaternions

    DEFF Research Database (Denmark)

    Henriksen, Knud; Erleben, Kenny; Engell-Nørregård, Morten

    In this project I describe the status of inverse kinematics research, with the focus firmly on the methods that solve the core problem. An overview of the different methods are presented Three common methods used in inverse kinematics computation have been chosen as subject for closer inspection....... suite, developed in this project and in [4]. Source code developed for this project includes the CCD method , improvements on the BFGS method and Jacobian inverse originally developed in [4]....

  20. Inverse periodic shadowing properties

    CERN Document Server

    Osipov, Alexey V

    2011-01-01

    We consider inverse periodic shadowing properties of discrete dynamical systems generated by diffeomorphisms of closed smooth manifolds. We show that the $C^1$-interior of the set of all diffeomorphisms having so-called inverse periodic shadowing property coincides with the set of $\\Omega$-stable diffeomorphisms. The equivalence of Lipschitz inverse periodic shadowing property and hyperbolicity of the closure of all periodic points is proved. Besides, we prove that the set of all diffeomorphisms that have Lipschitz inverse periodic shadowing property and whose periodic points are dense in the nonwandering set coincides with the set of Axiom A diffeomorphisms.

  1. Town Centre Redevelopment Strategies

    DEFF Research Database (Denmark)

    Vagnby, Bo Hellisen

    After many years of urban growth Danish downtowns are facing some important choices. Shall the stake one-sidedly be on the town centres as driving forces for growth and 'city marketing', or do they still have a role to play in a broader socio-economic context? In the paper we look back on eight...... as slum clearence and urban renewal. To a certain extent parallels are drawn to international experiences, especially where these are of such a nature that they can be assumed transferred to Danish connctions. Conclusively, the strategies are discussed in the light of the turn of Danish urban planning...

  2. Dynamical inverse problems

    CERN Document Server

    Gladwell, Graham ML

    2011-01-01

    The papers in this volume present an overview of the general aspects and practical applications of dynamic inverse methods, through the interaction of several topics, ranging from classical and advanced inverse problems in vibration, isospectral systems, dynamic methods for structural identification, active vibration control and damage detection, imaging shear stiffness in biological tissues, wave propagation, to computational and experimental aspects relevant for engineering problems.

  3. Inverse Symmetric Inflationary Attractors

    CERN Document Server

    Odintsov, S D

    2016-01-01

    We present a class of inflationary potentials which are invariant under a special symmetry, which depends on the parameters of the models. As we show, in certain limiting cases, the inverse symmetric potentials are qualitatively similar to the $\\alpha$-attractors models, since the resulting observational indices are identical. However, there are some quantitative differences which we discuss in some detail. As we show, some inverse symmetric models always yield results compatible with observations, but this strongly depends on the asymptotic form of the potential at large $e$-folding numbers. In fact when the limiting functional form is identical to the one corresponding to the $\\alpha$-attractors models, the compatibility with the observations is guaranteed. Also we find the relation of the inverse symmetric models with the Starobinsky model and we highlight the differences. In addition, an alternative inverse symmetric model is studied and as we show, not all the inverse symmetric models are viable. Moreove...

  4. 0-Semidistributive Inverse Semigroups

    Institute of Scientific and Technical Information of China (English)

    田振际

    2004-01-01

    @@ For an inverse semigroup S, the set L(S) of all inverse subsemigroups (including the empty set) of S forms a lattice with respect to intersection denoted as usual by ∩ and union, where the union is the inverse subsemigroup generated by inverse subsemigroups A, B of S. The set LF(S) of all full inverse subsemigroups of S forms a complete sublattice of L(S), with Es as zero element (Es is the set of all idempotent of S)(see [3,5,6]). Note, that if S a group, then LF(S)=L(S), its lattice of all subgroups of S. If S = G0 is a group with adjoined zero, then clearly LF(S) ≌ L(G).

  5. Stavanger Squash Centre, Norway

    Energy Technology Data Exchange (ETDEWEB)

    Rostvik, H. [Sunlab/ABB, Stavanger (Norway)

    1999-07-01

    Although Stavanger is the technological and financial oil-capital of Norway, the Stavanger Squash Centre was until recently the largest solar building in Norway, with 120 m{sup 2} of collectors. The active, building-integrated, solar air collector in the 45 {sup o} roof facing 15 {sup o} east of due south, has now been delivering solar-heated hot water for the showers for 15 years. The solar system consists of several standard products put together in a new way. Monitoring has shown that the system produced 18,000 kWh/m{sup 2} a (150 kWh/m{sub coll} {sup 2}a). If operated as planned, it could have had a solar contribution of 45,000 kWh/a) (375 kWh/m{sub coll} {sup 2}a), resulting in a 19% solar fraction of total demand. (author)

  6. A cancer help centre.

    Science.gov (United States)

    Daniel, R

    1996-06-01

    The diagnosis of cancer can be shattering to all involved. The treatment of cancer is intense and often very challenging. Prevailing attitudes to cancer are sometimes fearful, negative and depressing. This combination may leave those affected by cancer shocked, disorientated and without hope. Even worse than this, on asking consultants 'What can I do to help myself?' patients are frequently told 'Absolutely nothing'--crushing in one fell swoop their remaining fighting spirit. Not so in the case of Penny Brohn, who, when faced with the diagnosis of breast cancer, travelled the world to find alternative cancer treatments, and having successfully brought her own cancer under control, dedicated her life to creating a Centre for others wishing to fight their disease.

  7. Crystallographic B factor of critical residues at enzyme active site

    Institute of Scientific and Technical Information of China (English)

    张海龙; 宋时英; 林政炯

    1999-01-01

    Thirty-seven sets of crystallographic enzyme data were selected from Protein Data Bank (PDB, 1995). The average temperature factors (B) of the critical residues at the active site and the whole molecule of those enzymes were calculated respectively. The statistical results showed that the critical residues at the active site of most of the enzymes had lower B factors than did the whole molecules, indicating that in the crystalline state the critical residues at the active site of the natural enzymes possess more stable conformation than do the whole molecules. The flexibility of the active site during the unfolding by denaturing was also discussed.

  8. Function representation with circle inversion map systems

    Science.gov (United States)

    Boreland, Bryson; Kunze, Herb

    2017-01-01

    The fractals literature develops the now well-known concept of local iterated function systems (using affine maps) with grey-level maps (LIFSM) as an approach to function representation in terms of the associated fixed point of the so-called fractal transform. While originally explored as a method to achieve signal (and 2-D image) compression, more recent work has explored various aspects of signal and image processing using this machinery. In this paper, we develop a similar framework for function representation using circle inversion map systems. Given a circle C with centre õ and radius r, inversion with respect to C transforms the point p˜ to the point p˜', such that p˜ and p˜' lie on the same radial half-line from õ and d(õ, p˜)d(õ, p˜') = r2, where d is Euclidean distance. We demonstrate the results with an example.

  9. Call Centre- Computer Telephone Integration

    Directory of Open Access Journals (Sweden)

    Dražen Kovačević

    2012-10-01

    Full Text Available Call centre largely came into being as a result of consumerneeds converging with enabling technology- and by the companiesrecognising the revenue opportunities generated by meetingthose needs thereby increasing customer satisfaction. Regardlessof the specific application or activity of a Call centre, customersatisfaction with the interaction is critical to the revenuegenerated or protected by the Call centre. Physical(v, Call centreset up is a place that includes computer, telephone and supervisorstation. Call centre can be available 24 hours a day - whenthe customer wants to make a purchase, needs information, orsimply wishes to register a complaint.

  10. Should "Teacher Centred Teaching" Replace "Student Centred Learning"?

    Science.gov (United States)

    Bailey, Patrick D.

    2008-01-01

    Mission statements of most HEIs across the UK support "student centred learning". In this paper, it is suggested that "teacher centred teaching" should also have a major role to play, improving the quality of the learning experience in higher education. Students are extremely diverse in their skills, weaknesses, and learning…

  11. Crystallographic Orientation Effect on Electromigration in Ni-Sn Microbump

    Science.gov (United States)

    Huang, Yi-Ting; Chen, Chih-Hao; Chakroborty, Subhendu; Wu, Albert T.

    2017-09-01

    This article addresses the reliability challenges regarding electromigration in developing three-dimensional integrated circuits (3D-ICs). The line-type sandwich structure of Ni/Sn3.5Ag(15 μm)/Ni was used to simulate microbumps to examine the reliability of electromigration in 3D-IC technology. The solder strip of Ni/Sn3.5Ag(15 μm)/Ni was stressed with a current density of 1.0 × 104 A/cm2 at 150°C. The current stressing enhanced the reaction between the solder and Ni to form Ni3Sn4, which occupied the entire joint and transformed into a Ni/Ni3Sn4/Ni structure when the solder was completely consumed. Electron backscatter diffraction was used to analyze the crystallographic characteristics of Sn and Ni3Sn4 as related to the electromigration effect. The results indicated that the crystallographic orientation of Sn plays a significant role in the Ni/Sn3.5Ag/Ni, whereas the orientation of Ni3Sn4 is the dominant factor of diffusion behavior in the Ni/Ni3Sn4/Ni.

  12. Crystallographic properties of magnetron sputtered barium ferrite films

    Energy Technology Data Exchange (ETDEWEB)

    Capraro, S. [Laboratoire DIOM, University of Saint-Etienne, 23 rue Michelon, 42023 Saint-Etienne Cedex (France)]. E-mail: stephane.capraro@univ-st-etienne.fr; Berre, M. Le [LPM, UMR 5511, INSA Lyon, 7 av. Jean Capelle, 69621 Villeurbanne Cedex (France); Chatelon, J.P. [Laboratoire DIOM, University of Saint-Etienne, 23 rue Michelon, 42023 Saint-Etienne Cedex (France); Bayard, B. [Laboratoire DIOM, University of Saint-Etienne, 23 rue Michelon, 42023 Saint-Etienne Cedex (France); Joisten, H. [CEA-LETI, 17 rue des martyrs, 38041 Grenoble Cedex (France); Canut, C. [LPMCN, University Lyon I, 43 Bvd. du 11 novembre 1918, 69622 Villerbanne, Cedex (France); Barbier, D. [LPM, UMR 5511, INSA Lyon, 7 av. Jean Capelle, 69621 Villeurbanne Cedex (France); Rousseau, J.J. [Laboratoire DIOM, University of Saint-Etienne, 23 rue Michelon, 42023 Saint-Etienne Cedex (France)

    2004-09-15

    The development of devices combining a ferrite with a semiconductor chip is a major focus of current research. Barium hexaferrite (BaFe{sub 12}O{sub 19} or BaM) thick films are deposited here using a RF magnetron sputtering system. Films are amorphous and non magnetic after deposition. Post-deposition thermal annealing is employed to make the films crystallize. The effects of the substrate, thermal annealing process, thickness, substrate temperature on crystallographic properties and stoichiometry are studied using a X-ray diffractometry (XRD) and Rutherford back-scattering (RBS). The in-depth homogeneity of Ba, Fe and O is evaluated by secondary ion mass spectroscopy (SIMS). The study shows a good crystallization of BaM films and there is a preferential orientation among the crystallographic planes (1 0 1), (2 0 0), (2 0 3), (1 0 2), (1 1 0) and (2 0 5) when BaM films are prepared at low RF power and when the substrate is heated. For several elaboration parameters, grains size is in the range of 25 and 40 nm and BaM films are stoichiometric with regard to the target stoichiometry.

  13. Crystallographic Orientation Effect on Electromigration in Ni-Sn Microbump

    Science.gov (United States)

    Huang, Yi-Ting; Chen, Chih-Hao; Chakroborty, Subhendu; Wu, Albert T.

    2017-07-01

    This article addresses the reliability challenges regarding electromigration in developing three-dimensional integrated circuits (3D-ICs). The line-type sandwich structure of Ni/Sn3.5Ag(15 μm)/Ni was used to simulate microbumps to examine the reliability of electromigration in 3D-IC technology. The solder strip of Ni/Sn3.5Ag(15 μm)/Ni was stressed with a current density of 1.0 × 104 A/cm2 at 150°C. The current stressing enhanced the reaction between the solder and Ni to form Ni3Sn4, which occupied the entire joint and transformed into a Ni/Ni3Sn4/Ni structure when the solder was completely consumed. Electron backscatter diffraction was used to analyze the crystallographic characteristics of Sn and Ni3Sn4 as related to the electromigration effect. The results indicated that the crystallographic orientation of Sn plays a significant role in the Ni/Sn3.5Ag/Ni, whereas the orientation of Ni3Sn4 is the dominant factor of diffusion behavior in the Ni/Ni3Sn4/Ni.

  14. Crystallographic alignment of high-density gallium nitride nanowire arrays.

    Science.gov (United States)

    Kuykendall, Tevye; Pauzauskie, Peter J; Zhang, Yanfeng; Goldberger, Joshua; Sirbuly, Donald; Denlinger, Jonathan; Yang, Peidong

    2004-08-01

    Single-crystalline, one-dimensional semiconductor nanostructures are considered to be one of the critical building blocks for nanoscale optoelectronics. Elucidation of the vapour-liquid-solid growth mechanism has already enabled precise control over nanowire position and size, yet to date, no reports have demonstrated the ability to choose from different crystallographic growth directions of a nanowire array. Control over the nanowire growth direction is extremely desirable, in that anisotropic parameters such as thermal and electrical conductivity, index of refraction, piezoelectric polarization, and bandgap may be used to tune the physical properties of nanowires made from a given material. Here we demonstrate the use of metal-organic chemical vapour deposition (MOCVD) and appropriate substrate selection to control the crystallographic growth directions of high-density arrays of gallium nitride nanowires with distinct geometric and physical properties. Epitaxial growth of wurtzite gallium nitride on (100) gamma-LiAlO(2) and (111) MgO single-crystal substrates resulted in the selective growth of nanowires in the orthogonal [1\\[Evec]0] and [001] directions, exhibiting triangular and hexagonal cross-sections and drastically different optical emission. The MOCVD process is entirely compatible with the current GaN thin-film technology, which would lead to easy scale-up and device integration.

  15. Diffusion-equation method for crystallographic figure of merits.

    Science.gov (United States)

    Markvardsen, Anders J; David, William I F

    2010-09-01

    Global optimization methods play a significant role in crystallography, particularly in structure solution from powder diffraction data. This paper presents the mathematical foundations for a diffusion-equation-based optimization method. The diffusion equation is best known for describing how heat propagates in matter. However, it has also attracted considerable attention as the basis for global optimization of a multimodal function [Piela et al. (1989). J. Phys. Chem. 93, 3339-3346]. The method relies heavily on available analytical solutions for the diffusion equation. Here it is shown that such solutions can be obtained for two important crystallographic figure-of-merit (FOM) functions that fully account for space-group symmetry and allow the diffusion-equation solution to vary depending on whether atomic coordinates are fixed or not. The resulting expression is computationally efficient, taking the same order of floating-point operations to evaluate as the starting FOM function measured in terms of the number of atoms in the asymmetric unit. This opens the possibility of implementing diffusion-equation methods for crystallographic global optimization algorithms such as structure determination from powder diffraction data.

  16. Crystallographic studies of gas sorption in metal–organic frameworks

    Science.gov (United States)

    Carrington, Elliot J.; Vitórica-Yrezábal, Iñigo J.; Brammer, Lee

    2014-01-01

    Metal–organic frameworks (MOFs) are a class of porous crystalline materials of modular design. One of the primary applications of these materials is in the adsorption and separation of gases, with potential benefits to the energy, transport and medical sectors. In situ crystallography of MOFs under gas atmospheres has enabled the behaviour of the frameworks under gas loading to be investigated and has established the precise location of adsorbed gas molecules in a significant number of MOFs. This article reviews progress in such crystallographic studies, which has taken place over the past decade, but has its origins in earlier studies of zeolites, clathrates etc. The review considers studies by single-crystal or powder diffraction using either X-rays or neutrons. Features of MOFs that strongly affect gas sorption behaviour are discussed in the context of in situ crystallographic studies, specifically framework flexibility, and the presence of (organic) functional groups and unsaturated (open) metal sites within pores that can form specific interactions with gas molecules. PMID:24892587

  17. On Generalized Inverse Transversals

    Institute of Scientific and Technical Information of China (English)

    Rong Hua ZHANG; Shou Feng WANG

    2008-01-01

    Let S be a regular semigroup,S° an inverse subsemigroup of S.S° is called a generalized inverse transversal of S,if V(x) ∩N S°≠φ.In this paper,some properties of this kind of semigroups are discussed.In particular,a construction theorem is obtained which contains some recent results in the literature as its special cases.

  18. The inverse electroencephalography pipeline

    Science.gov (United States)

    Weinstein, David Michael

    The inverse electroencephalography (EEG) problem is defined as determining which regions of the brain are active based on remote measurements recorded with scalp EEG electrodes. An accurate solution to this problem would benefit both fundamental neuroscience research and clinical neuroscience applications. However, constructing accurate patient-specific inverse EEG solutions requires complex modeling, simulation, and visualization algorithms, and to date only a few systems have been developed that provide such capabilities. In this dissertation, a computational system for generating and investigating patient-specific inverse EEG solutions is introduced, and the requirements for each stage of this Inverse EEG Pipeline are defined and discussed. While the requirements of many of the stages are satisfied with existing algorithms, others have motivated research into novel modeling and simulation methods. The principal technical results of this work include novel surface-based volume modeling techniques, an efficient construction for the EEG lead field, and the Open Source release of the Inverse EEG Pipeline software for use by the bioelectric field research community. In this work, the Inverse EEG Pipeline is applied to three research problems in neurology: comparing focal and distributed source imaging algorithms; separating measurements into independent activation components for multifocal epilepsy; and localizing the cortical activity that produces the P300 effect in schizophrenia.

  19. Generalized emissivity inverse problem.

    Science.gov (United States)

    Ming, DengMing; Wen, Tao; Dai, XianXi; Dai, JiXin; Evenson, William E

    2002-04-01

    Inverse problems have recently drawn considerable attention from the physics community due to of potential widespread applications [K. Chadan and P. C. Sabatier, Inverse Problems in Quantum Scattering Theory, 2nd ed. (Springer Verlag, Berlin, 1989)]. An inverse emissivity problem that determines the emissivity g(nu) from measurements of only the total radiated power J(T) has recently been studied [Tao Wen, DengMing Ming, Xianxi Dai, Jixin Dai, and William E. Evenson, Phys. Rev. E 63, 045601(R) (2001)]. In this paper, a new type of generalized emissivity and transmissivity inverse (GETI) problem is proposed. The present problem differs from our previous work on inverse problems by allowing the unknown (emissivity) function g(nu) to be temperature dependent as well as frequency dependent. Based on published experimental information, we have developed an exact solution formula for this GETI problem. A universal function set suggested for numerical calculation is shown to be robust, making this inversion method practical and convenient for realistic calculations.

  20. Council celebrates CERN Control Centre

    CERN Multimedia

    2006-01-01

    With the unveiling of its new sign, the CERN Control Centre was officially inaugurated on Thursday 16 March. To celebrate its startup, CERN Council members visited the sleek centre, a futuristic-looking room filled with a multitude of monitoring screens.

  1. Automatic loop centring with a high-precision goniometer head at the SLS macromolecular crystallography beamlines

    Energy Technology Data Exchange (ETDEWEB)

    Pauluhn, Anuschka, E-mail: anuschka.pauluhn@psi.ch; Pradervand, Claude; Rossetti, Daniel; Salathe, Marco; Schulze-Briese, Clemens [Paul Scherrer Institut, CH-5232 Villigen (Switzerland)

    2011-07-01

    An automated loop-centring program and a high-precision goniometer head used at the Swiss Light Source are described. Automatic loop centring has been developed as part of the automation process in crystallographic data collection at the Swiss Light Source. The procedure described here consists of an optional set-up part, in which the background images are taken, and the actual centring part. The algorithm uses boundary and centre-of-mass detection at two different microscope image magnifications. Micromounts can be handled as well. Centring of the loops can be achieved in 15–26 s, depending on their initial position, and as fast as manual centring. The alignment of the sample is carried out by means of a new flexural-hinge-based compact goniometer head. The device features an electromagnet for robotic wet mounting of samples. The circle of confusion was measured to be smaller than 1 µm (r.m.s.); its bidirectional backlash is below 2 µm.

  2. CMCC Data Distribution Centre

    Science.gov (United States)

    Aloisio, Giovanni; Fiore, Sandro; Negro, A.

    2010-05-01

    The CMCC Data Distribution Centre (DDC) is the primary entry point (web gateway) to the CMCC. It is a Data Grid Portal providing a ubiquitous and pervasive way to ease data publishing, climate metadata search, datasets discovery, metadata annotation, data access, data aggregation, sub-setting, etc. The grid portal security model includes the use of HTTPS protocol for secure communication with the client (based on X509v3 certificates that must be loaded into the browser) and secure cookies to establish and maintain user sessions. The CMCC DDC is now in a pre-production phase and it is currently used only by internal users (CMCC researchers and climate scientists). The most important component already available in the CMCC DDC is the Search Engine which allows users to perform, through web interfaces, distributed search and discovery activities by introducing one or more of the following search criteria: horizontal extent (which can be specified by interacting with a geographic map), vertical extent, temporal extent, keywords, topics, creation date, etc. By means of this page the user submits the first step of the query process on the metadata DB, then, she can choose one or more datasets retrieving and displaying the complete XML metadata description (from the browser). This way, the second step of the query process is carried out by accessing to a specific XML document of the metadata DB. Finally, through the web interface, the user can access to and download (partially or totally) the data stored on the storage device accessing to OPeNDAP servers and to other available grid storage interfaces. Requests concerning datasets stored in deep storage will be served asynchronously.

  3. Crystallographic shear mechanisms in Rh one-dimensional oxides

    Science.gov (United States)

    Hernando, María; Boulahya, Khalid; Parras, Marina; González-Calbet, José M.

    2005-02-01

    Electron diffraction and high resolution electron microscopy have been used to characterize two new one-dimensional superstructures in the A sbnd Rh sbnd O system (A = Ca, Sr) related to the 2H-ABO 3-type. They are formed by the intergrowth of n A 3A'BO 6 blocks, showing the Sr 4RhO 6-type, with A 12A' 2B 8O 30 blocks, constituted by two A 3O 9 and two A 3A'O 6 layers alternating in the stacking sequence 1:1, leading to the A 27A' 7B 13O 60 ( n=5) and A 30A' 8B 14O 66 ( n=6) compositions. A crystallographic shear mechanism is proposed to describe the structural relationship between Sr 4RhO 6 (A 3A'BO 6-type) and the new superstructures.

  4. 3D characterization of crystallographic orientation in polycrystals via EBSD

    Institute of Scientific and Technical Information of China (English)

    Stefan ZAEFFERER; Stuart I. WRIGHT

    2007-01-01

    Electron Backscatter Diffraction (EBSD) has been used in conjunction with a Scanning Electron Microscope (SEM) combined with a focused ion beam (FIB) instrument to obtain three dimensional (3D) high resolution characterizations of crystalline microstructures. This work reports on continued development that has proceeded on this technique. The technique is based on automated in-situ serial sectioning using the FIB and characterization of the sections using automated EBSD or orientation imaging microscopy (OIM). The technique extends the powerful features of two dimensional OIM into the third spatial dimension. This allows additional descriptive microstructural parameters to be obtained, for example the morphology and the crystallographic indices of interface planes. This paper provides an overview of the technique and shows results from two different samples: pearlite colonies in a high carbon steel and twin related grain triplets in a NiCo thin film.

  5. Crystallographic texturing in Nb3Sn multifilamentary superconducting composites

    Science.gov (United States)

    Cogan, Stuart F.; Rose, Robert M.

    1980-03-01

    Crystallographic texturing in Nb3Sn composites, fabricated by both the external diffusion and the commercial bronze processes, has been investigated. In the external-diffusion-processed composite the as-drawn texture of the copper matrix contained ca. 55% and 45% ; after recrystallization at 650 °C for 16 h this changed to 70% and 30% . Tin plating and reaction heat treatment for 40 h at 650 °C eliminated most of the texturing. In a commercial bronze-processed composite a or texture was obtained in the as-drawn bronze matrix, and after a reaction heat treatment at 700 °C for 30 h a diffuse texture was developed. In both composites the Nb3Sn reaction layer exhibited no preferred orientation.

  6. Ocean acidification reduces the crystallographic control in juvenile mussel shells.

    Science.gov (United States)

    Fitzer, Susan C; Cusack, Maggie; Phoenix, Vernon R; Kamenos, Nicholas A

    2014-10-01

    Global climate change threatens the oceans as anthropogenic carbon dioxide causes ocean acidification and reduced carbonate saturation. Future projections indicate under saturation of aragonite, and potentially calcite, in the oceans by 2100. Calcifying organisms are those most at risk from such ocean acidification, as carbonate is vital in the biomineralisation of their calcium carbonate protective shells. This study highlights the importance of multi-generational studies to investigate how marine organisms can potentially adapt to future projected global climate change. Mytilus edulis is an economically important marine calcifier vulnerable to decreasing carbonate saturation as their shells comprise two calcium carbonate polymorphs: aragonite and calcite. M. edulis specimens were cultured under current and projected pCO2 (380, 550, 750 and 1000μatm), following 6months of experimental culture, adults produced second generation juvenile mussels. Juvenile mussel shells were examined for structural and crystallographic orientation of aragonite and calcite. At 1000μatm pCO2, juvenile mussels spawned and grown under this high pCO2 do not produce aragonite which is more vulnerable to carbonate under-saturation than calcite. Calcite and aragonite were produced at 380, 550 and 750μatm pCO2. Electron back scatter diffraction analyses reveal less constraint in crystallographic orientation with increased pCO2. Shell formation is maintained, although the nacre crystals appear corroded and crystals are not so closely layered together. The differences in ultrastructure and crystallography in shells formed by juveniles spawned from adults in high pCO2 conditions may prove instrumental in their ability to survive ocean acidification. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Transuranic Hybrid Materials: Crystallographic and Computational Metrics of Supramolecular Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Surbella, Robert G. [Department; Ducati, Lucas C. [Department; Pellegrini, Kristi L. [Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354, United States; McNamara, Bruce K. [Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354, United States; Autschbach, Jochen [Department; Schwantes, Jon M. [Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354, United States; Cahill, Christopher L. [Department

    2017-07-26

    A family of twelve supramolecular [AnO2Cl4]2- (An = U, Np, Pu) containing compounds assembled via hydrogen and halogen bonds donated by substituted 4-X-pyridinium cations (X = H, Cl, Br, I) is reported. These materials were prepared from a room-temperature synthesis wherein crystallization of unhydrolyzed and valence pure [An(VI)O2Cl4]2- (An = U, Np, Pu) tectons are the norm. We present a hierarchy of assembly criteria based on crystallographic observations, and subsequently quantify the strengths of the non-covalent interactions using Kohn-Sham density functional calculations. We provide, for the first time, a detailed description of the electrostatic potentials (ESPs) of the actinyl tetrahalide dianions and reconcile crystallographically observed structural motifs and non-covalent interaction (NCI) acceptor-donor pairings. Our findings indicate that the average electrostatic potential across the halogen ligands (the acceptors) changes by only ~2 kJ mol-1 across the AnO22+ series, indicating the magnitude of the potential is independent of the metal center. The role of the cation is therefore critical in directing structural motifs and dictating the resulting hydrogen and halogen bond strengths, the former being stronger due to the positive charge centralized on the pyridyl nitrogen N-H+. Subsequent analyses using the Quantum theory of atoms in molecules (QTAIM) and natural bond orbital (NBO) approaches support this conclusion and highlight the structure directing role of the cations. Whereas one can infer that the 2 Columbic attraction is the driver for assembly, the contribution of the non-covalent interaction is to direct the molecular-level arrangement (or disposition) of the tectons.

  8. Sharp spatially constrained inversion

    DEFF Research Database (Denmark)

    Vignoli, Giulio G.; Fiandaca, Gianluca G.; Christiansen, Anders Vest C A.V.C.;

    2013-01-01

    We present sharp reconstruction of multi-layer models using a spatially constrained inversion with minimum gradient support regularization. In particular, its application to airborne electromagnetic data is discussed. Airborne surveys produce extremely large datasets, traditionally inverted...... by using smoothly varying 1D models. Smoothness is a result of the regularization constraints applied to address the inversion ill-posedness. The standard Occam-type regularized multi-layer inversion produces results where boundaries between layers are smeared. The sharp regularization overcomes......, the results are compatible with the data and, at the same time, favor sharp transitions. The focusing strategy can also be used to constrain the 1D solutions laterally, guaranteeing that lateral sharp transitions are retrieved without losing resolution. By means of real and synthetic datasets, sharp...

  9. Minister unveils new nanotech centres

    Science.gov (United States)

    Dumé, Belle

    2009-06-01

    Three new nanotechnology research centres are to be set up in France as part of a €70m government plan to help French companies in the sector. Researchers at the new centres, which will be located in Grenoble, Saclay (near Paris) and Toulouse, will be encouraged to collaborate with industry to develop new nanotech-based products. Dubbed NANO-INNOV, the new plan includes €46m for two new buildings at Saclay, with the rest being used to buy new equipment at the three centres and to fund grant proposals from staff to the French National Research Agency (ANR).

  10. 25 years Nuclear Research Centre

    Energy Technology Data Exchange (ETDEWEB)

    Harde, R.

    1981-07-01

    On June 12, the Karlsruhe Nuclear Research Centre celebrated its 25th anniversary. The Centre was founded on July 19, 1956. The importance of this institution became apparent by the large number of prominent guests, at the head, the Federal President, Karl Carstens. Minister President Spaeth and the Federal Minister for Research and Technology, von Buelow, appreciated the achievements obtained by this big science centre of nuclear technology. The ceremony held in the State theatre of Baden-Wuerttemberg gave testimony of an impressing confession in favour of nuclear energy. Excerpts from the speech of the Chairman of the Managing Board, Prof. Harde, are quoted.

  11. The World Heritage Centr

    Directory of Open Access Journals (Sweden)

    Ayman G. Abdel Tawab

    2014-09-01

    Full Text Available New Gourna Village, which is located inside one of the World Heritage Sites in Egypt, has never been recognized as an element contributing to the site’s Outstanding Universal Value. The recognition of the village as a contributing element is reliant on the successful assessment of its authenticity and integrity. Responding to the dramatically declining integrity of the village, the World Heritage Centre has carried out an architectural study to guide the potential conservation works in the property. The study has recommended that a group of objectives and two approaches to the conservation of the village should be adopted. One of these two approaches has been concerned with the conservation of the village according to the architect’s original intentions and principles. The previous approach can be called the principles-based approach. The main aim of this study was to examine the agreement of the World Heritage Centre’s objectives and their proposed principles-based approach to the conservation of the village with the aim to improve its chance in meeting the conditions of authenticity and integrity. The study approached the previous aim by assessing, by means of a proposed methodology; the level of significance, authenticity and integrity of the property. Based on the previous assessment, a list of conservation interventions was proposed to improve the property’s chance in meeting the conditions of authenticity and integrity. Finally, the World Heritage Centre’s recommended approaches and objectives were examined against the previous proposed conservation interventions. The findings indicated the possibility to adopt the principles-based approach to the conservation of New Gourna Village, as well as the other World Heritage Centre’s objectives, without limiting the property’s chance in meeting the conditions of authenticity and integrity. The study recommends to carry out further studies that are concerned with the identification

  12. Limits to Nonlinear Inversion

    DEFF Research Database (Denmark)

    Mosegaard, Klaus

    2012-01-01

    For non-linear inverse problems, the mathematical structure of the mapping from model parameters to data is usually unknown or partly unknown. Absence of information about the mathematical structure of this function prevents us from presenting an analytical solution, so our solution depends on our......-heuristics are inefficient for large-scale, non-linear inverse problems, and that the 'no-free-lunch' theorem holds. We discuss typical objections to the relevance of this theorem. A consequence of the no-free-lunch theorem is that algorithms adapted to the mathematical structure of the problem perform more efficiently than...

  13. 'Inverse' temporomandibular joint dislocation.

    Science.gov (United States)

    Alemán Navas, R M; Martínez Mendoza, M G

    2011-08-01

    Temporomandibular joint (TMJ) dislocation can be classified into four groups (anterior, posterior, lateral, and superior) depending on the direction of displacement and the location of the condylar head. All the groups are rare except for anterior dislocation. 'Inverse' TMJ dislocation is a bilateral anterior and superior dislocation with impaction of the mandible over the maxilla; to the authors' knowledge only two cases have previously been reported in the literature. Inverse TMJ dislocation has unique clinical and radiographic findings, which are described for this case. Copyright © 2011 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  14. The centre of the action

    CERN Multimedia

    2008-01-01

    The CERN Control Centre (CCC) has all the ingredients of an action movie control room: hundreds of screens, technicians buzzing in and out, huge floor-to-ceiling windows revealing the looming vista of a mountain range, flashing lights, microphones… This is the place where not just the LHC, but the whole of CERN’s accelerator complex and technical support is based - truly the centre of the action at CERN.

  15. Locative Inversion in English

    NARCIS (Netherlands)

    Broekhuis, H.

    2005-01-01

    This article aims at reformulating in more current terms Hoekstra and Mulder’s (1990) analysis of the Locative Inversion (LI) construction. The new proposal is crucially based on the assumption that Small Clause (SC) predicates agree with their external argument in phi-features, which may be morphol

  16. Inverse Kinematic Analysis of Human Hand Thumb Model

    Science.gov (United States)

    Toth-Tascau, Mirela; Pater, Flavius; Stoia, Dan Ioan; Menyhardt, Karoly; Rosu, Serban; Rusu, Lucian; Vigaru, Cosmina

    2011-09-01

    This paper deals with a kinematic model of the thumb of the human hand. The proposed model has 3 degrees of freedom being able to model the movements of the thumb tip with respect to the wrist joint centre. The kinematic equations are derived based on Denavit-Hartenberg Convention and solved in both direct and inverse way. Inverse kinematic analysis of human hand thumb model reveals multiple and connected solutions which are characteristic to nonlinear systems when the number of equations is greater than number of unknowns and correspond to natural movements of the finger.

  17. Bayesian seismic AVO inversion

    Energy Technology Data Exchange (ETDEWEB)

    Buland, Arild

    2002-07-01

    A new linearized AVO inversion technique is developed in a Bayesian framework. The objective is to obtain posterior distributions for P-wave velocity, S-wave velocity and density. Distributions for other elastic parameters can also be assessed, for example acoustic impedance, shear impedance and P-wave to S-wave velocity ratio. The inversion algorithm is based on the convolutional model and a linearized weak contrast approximation of the Zoeppritz equation. The solution is represented by a Gaussian posterior distribution with explicit expressions for the posterior expectation and covariance, hence exact prediction intervals for the inverted parameters can be computed under the specified model. The explicit analytical form of the posterior distribution provides a computationally fast inversion method. Tests on synthetic data show that all inverted parameters were almost perfectly retrieved when the noise approached zero. With realistic noise levels, acoustic impedance was the best determined parameter, while the inversion provided practically no information about the density. The inversion algorithm has also been tested on a real 3-D dataset from the Sleipner Field. The results show good agreement with well logs but the uncertainty is high. The stochastic model includes uncertainties of both the elastic parameters, the wavelet and the seismic and well log data. The posterior distribution is explored by Markov chain Monte Carlo simulation using the Gibbs sampler algorithm. The inversion algorithm has been tested on a seismic line from the Heidrun Field with two wells located on the line. The uncertainty of the estimated wavelet is low. In the Heidrun examples the effect of including uncertainty of the wavelet and the noise level was marginal with respect to the AVO inversion results. We have developed a 3-D linearized AVO inversion method with spatially coupled model parameters where the objective is to obtain posterior distributions for P-wave velocity, S

  18. Calculation of the inverse data space via sparse inversion

    KAUST Repository

    Saragiotis, Christos

    2011-01-01

    The inverse data space provides a natural separation of primaries and surface-related multiples, as the surface multiples map onto the area around the origin while the primaries map elsewhere. However, the calculation of the inverse data is far from trivial as theory requires infinite time and offset recording. Furthermore regularization issues arise during inversion. We perform the inversion by minimizing the least-squares norm of the misfit function by constraining the $ell_1$ norm of the solution, being the inverse data space. In this way a sparse inversion approach is obtained. We show results on field data with an application to surface multiple removal.

  19. Pseudo waveform inversion

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Chang Soo; Park, Keun Pil [Korea Inst. of Geology Mining and Materials, Taejon (Korea, Republic of); Suh, Jung Hee; Hyun, Byung Koo; Shin, Sung Ryul [Seoul National University, Seoul (Korea, Republic of)

    1995-12-01

    The seismic reflection exploration technique which is one of the geophysical methods for oil exploration became effectively to image the subsurface structure with rapid development of computer. However, the imagining of subsurface based on the conventional data processing is almost impossible to obtain the information on physical properties of the subsurface such as velocity and density. Since seismic data are implicitly function of velocities of subsurface, it is necessary to develop the inversion method that can delineate the velocity structure using seismic topography and waveform inversion. As a tool to perform seismic inversion, seismic forward modeling program using ray tracing should be developed. In this study, we have developed the algorithm that calculate the travel time of the complex geologic structure using shooting ray tracing by subdividing the geologic model into blocky structure having the constant velocity. With the travel time calculation, the partial derivatives of travel time can be calculated efficiently without difficulties. Since the current ray tracing technique has a limitation to calculate the travel times for extremely complex geologic model, our aim in the future is to develop the powerful ray tracer using the finite element technique. After applying the pseudo waveform inversion to the seismic data of Korea offshore, we can obtain the subsurface velocity model and use the result in bring up the quality of the seismic data processing. If conventional seismic data processing and seismic interpretation are linked with this inversion technique, the high quality of seismic data processing can be expected to image the structure of the subsurface. Future research area is to develop the powerful ray tracer of ray tracing which can calculate the travel times for the extremely complex geologic model. (author). 39 refs., 32 figs., 2 tabs.

  20. The ideal Atomic Centre; Le Centre Atomique ideal

    Energy Technology Data Exchange (ETDEWEB)

    Mas, R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    The author presents considerations which should prove to be of interest to all those who have to design, to construct and to operate a nuclear research centre. A large number of the ideas presented can also be applied to non-nuclear scientific research centres. In his report the author reviews: various problems with which the constructor is faced: ground-plan, infrastructure, buildings and the large units of scientific equipment in the centre, and those problems facing the director: maintenance, production, supplies, security. The author stresses the relationship which ought to exist between the research workers and the management. With this aim in view he proposes the creation of National School for Administration in Research which would train administrative executives for public or private organisations; they would be specialised in the fields of fundamental or applied research. (author) [French] L'auteur propose une base de reflexions a tous ceux qui doivent concevoir, realiser et faire vivre un Centre d'Etudes Nucleaires. Un grand nombre des idees exprimees peut d'ailleurs s'appliquer a un Centre d'Etudes Scientifiques non nucleaires. Dans son ouvrage, l'auteur passe en revue les differents problemes qui se posent au constructeur: plan, masse, infrastructure, batiments et grands appareils du Centre, et ceux qu'a a resoudre le directeur: entretien, fabrication, approvisionnements, securite. L'auteur insiste sur l'aspect des rapports qui doivent exister entre les chercheurs et ceux qui les administrent. Il propose a cette fin la creation d'une Ecole Nationale d'Administration de la Recherche qui formerait des cadres administratifs pour les organismes publics ou prives, specialises dans la Recherche fondamentale ou appliquee. (auteur)

  1. Measurements of control rod worth by modified inverse kinetic method

    Energy Technology Data Exchange (ETDEWEB)

    Bobrov, A. A.; Lebedev, G. V., E-mail: lgv2004@mail.ru; Nechaev, Yu. A. [Russian Research Centre Kurchatov Institute (Russian Federation)

    2011-12-15

    Results of control rod worth measurements on the Astra critical assembly at the Russian Research Centre Kurchatov Institute are presented. The measurements were carried out by the modified inverse kinetics method, which is based on the use of experimental information about the variation of neutron detector readings only after introducing a reactivity perturbation. Calculated corrections are not required. The results of measurements do not depend on the neutron detector position.

  2. An introduction to the tools hosted in the Bilbao Crystallographic Server

    Directory of Open Access Journals (Sweden)

    Aroyo M.I.

    2012-03-01

    Full Text Available The programs hosted in the Bilbao Crystallographic Server (http://www.cryst.ehu.es are briefly explained along with worked examples on various cases related to different fields of applications. It is our aim to have this text acting as a primer on the various usage of the crystallographic tools in conjunction with each other due to the modular structure of the server. For this reason, diverse topics such as crystallographic groups and their subgroups, pseudosymmetry, extinction conditions, k-vectors and irreducible representations have been discussed in the context.

  3. Nanocrystalline materials: recent advances in crystallographic characterization techniques

    Directory of Open Access Journals (Sweden)

    Emilie Ringe

    2014-11-01

    Full Text Available Most properties of nanocrystalline materials are shape-dependent, providing their exquisite tunability in optical, mechanical, electronic and catalytic properties. An example of the former is localized surface plasmon resonance (LSPR, the coherent oscillation of conduction electrons in metals that can be excited by the electric field of light; this resonance frequency is highly dependent on both the size and shape of a nanocrystal. An example of the latter is the marked difference in catalytic activity observed for different Pd nanoparticles. Such examples highlight the importance of particle shape in nanocrystalline materials and their practical applications. However, one may ask `how are nanoshapes created?', `how does the shape relate to the atomic packing and crystallography of the material?', `how can we control and characterize the external shape and crystal structure of such small nanocrystals?'. This feature article aims to give the reader an overview of important techniques, concepts and recent advances related to these questions. Nucleation, growth and how seed crystallography influences the final synthesis product are discussed, followed by shape prediction models based on seed crystallography and thermodynamic or kinetic parameters. The crystallographic implications of epitaxy and orientation in multilayered, core-shell nanoparticles are overviewed, and, finally, the development and implications of novel, spatially resolved analysis tools are discussed.

  4. Pulsed neutron spectroscopic imaging for crystallographic texture and microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Hirotaka, E-mail: hakuryu@eng.hokudai.ac.jp [Graduate School of Engineering, Hokkaido University, Kita-13 Nishi-8, Kita-ku, Sapporo 060-8628 (Japan); Kamiyama, Takashi [Graduate School of Engineering, Hokkaido University, Kita-13 Nishi-8, Kita-ku, Sapporo 060-8628 (Japan); Iwase, Kenji; Ishigaki, Toru [Frontier Research Center for Applied Atomic Sciences, Ibaraki University, Ibaraki 319-1106 (Japan); Kiyanagi, Yoshiaki [Graduate School of Engineering, Hokkaido University, Kita-13 Nishi-8, Kita-ku, Sapporo 060-8628 (Japan)

    2011-09-21

    A time-of-flight (TOF) spectroscopic neutron imaging at a pulsed neutron source is expected to be a new material analysis tool because this method can non-destructively investigate the spatial dependence of the crystallographic and metallographic information in a bulk material. For quantitative evaluation of such information, a spectral analysis code for the transmission data is necessary. Therefore, we have developed a Rietveld-like analysis code, RITS. Furthermore, we have applied the RITS code to evaluation of the position dependence of the crystal orientation anisotropy, the preferred orientation and the crystallite size of a welded {alpha}-iron plate, and we successfully obtained the information on the texture and the microstructure. However, the reliability of the values given by the RITS code has not been evaluated yet in detail. For this reason, we compared the parameters provided by the RITS code with the parameters obtained by the neutron TOF powder diffractometry and its Rietveld analysis. Both the RITS code and the Rietveld analysis software indicated values close to each other, but there were systematic differences on the preferred orientation and the crystallite size.

  5. Crystallographic structure of ubiquitin in complex with cadmium ions

    Directory of Open Access Journals (Sweden)

    Cheung Peter

    2009-12-01

    Full Text Available Abstract Background Ubiquitination plays a critical role in regulating many cellular processes, from DNA repair and gene transcription to cell cycle and apoptosis. It is catalyzed by a specific enzymatic cascade ultimately leading to the conjugation of ubiquitin to lysine residues of the target protein that can be the ubiquitin molecule itself and to the formation of poly-ubiquitin chains. Findings We present the crystal structure at 3.0 Å resolution of bovine ubiquitin crystallized in presence of cadmium ions. Two molecules of ubiquitin are present in the asymmetric unit. Interestingly this non-covalent dimeric arrangement brings Lys-6 and Lys-63 of each crystallographically-independent monomer in close contact with the C-terminal ends of the other monomer. Residues Leu-8, Ile-44 and Val-70 that form a hydrophobic patch at the surface of the Ub monomer are trapped at the dimer interface. Conclusions The structural basis for signalling by poly-Ub chains relies on a visualization of conformations of alternatively linked poly-Ub chains. This arrangement of ubiquitin could illustrate how linkages involving Lys-6 or Lys-63 of ubiquitin are produced in the cell. It also details how ubiquitin molecules can specifically chelate cadmium ions.

  6. Cassia grandis Linn. f. seed galactomannan: structural and crystallographical studies.

    Science.gov (United States)

    Joshi, Harsha; Kapoor, Virendra P

    2003-09-01

    Cassia grandis is a small or medium sized tree, found in abundance throughout India. The seeds contain about 50% endosperm gum and possess the characteristics of becoming a potential source of seed gum. The purified polysaccharide has been characterized as a pure galactomannan having a mannose-galactose ratio of 3.15; molecular weight (Mw) 80,200; polydispersity (Mw/Mn), 1.35 and intrinsic viscosity [eta], 848 mL/g. Methylation, periodate oxidation, Smith degradation and 13C NMR studies confirm that the polysaccharide has the basic structure of legume galactomannans consisting of a beta-(1-->4)-linked main mannan backbone to which galactose units are attached at O-6. The orthorhombic lattice constants of the hydrated gum are as follows: a=9.00, b=24.81, c=10.30 A. The crystallographic data establish that the probable space group symmetry of the unit cell is P2(1)2(1)2. The results are in contradiction to earlier reports (Indian J. Chem. 16B (1978) 966; J. Indian Chem. Soc. 55 (1978) 1216) in which a non-galactomannan polysaccharide structure has been assigned having a main chain of (1-->4)-linked galactose and mannose units in the molar ratio 6:3, where 50% of the galactose units branched with two galactose and one mannose through 1-->3 linkage.

  7. Crystallographic analysis of amorphization caused by ion irradiation

    CERN Document Server

    Nakagawa, S T; Ono, T; Hada, Y; Betz, G

    2003-01-01

    Ion irradiation often causes amorphization in a crystal. We have presented a new crystallographic analysis that defines a new type of order parameter, which we call pixel mapping (PM). PM can describe algebraically to what extent and how the crystallinity has changed under ion bombardment. In other words, PM describes the long-range-order (LRO) interactions, based on the crystallography. PM can be effectively used, when it is incorporated in a classical molecular dynamics (MD) calculation. In the case of B ions implanted into a Si crystal, we observed crystal to amorphous (CA) transitions under energetic ion bombardment at low temperature. The PM profiling was more effective to reveal the CA transition than other atomistic methods of analyses as radial distribution function g(r) or vacancy mapping N sub v. PM could distinguish between perfect crystalline states, transition states, and random states. Moreover, PM revealed that the lattice reaction was cooperative even in a mesoscopic volume, e.g. in a cube of ...

  8. Crystallographic Orientation of Cuttlebone Shield Determined by Electron Backscatter Diffraction

    Science.gov (United States)

    Cusack, Maggie; Chung, Peter

    2014-01-01

    In common with many cephalopod mollusks, cuttlefish produce an internal biomineral buoyancy device. This cuttlebone is analogous to a surf board in shape and structure, providing rigidity and a means of controlling buoyancy. The cuttlebone is composed of calcium carbonate in the form of aragonite and comprises an upper dorsal shield and a lower lamellar matrix. The lamellar matrix comprises layers of chambers with highly corrugated walls. The dorsal shield comprises bundles of aragonite needles stacked on top of each other. Electron backscatter diffraction analyses of the dorsal shield reveal that the c-axis of aragonite is parallel with the long axis of the needles in the bundles such that any spread in crystallographic orientation is consistent with the spread in orientation of the fibers as they radiate to form the overall structure of the dorsal shield. This arrangement of c-axis coincident with the long axis of the biomineral structure is similar to the arrangement in corals and in contrast to the situation in the molluskan aragonite nacre of brachiopod calcite where the c-axis is perpendicular to the aragonite tablet or calcite fiber, respectively.

  9. Nanocrystalline materials: recent advances in crystallographic characterization techniques.

    Science.gov (United States)

    Ringe, Emilie

    2014-11-01

    Most properties of nanocrystalline materials are shape-dependent, providing their exquisite tunability in optical, mechanical, electronic and catalytic properties. An example of the former is localized surface plasmon resonance (LSPR), the coherent oscillation of conduction electrons in metals that can be excited by the electric field of light; this resonance frequency is highly dependent on both the size and shape of a nanocrystal. An example of the latter is the marked difference in catalytic activity observed for different Pd nanoparticles. Such examples highlight the importance of particle shape in nanocrystalline materials and their practical applications. However, one may ask 'how are nanoshapes created?', 'how does the shape relate to the atomic packing and crystallography of the material?', 'how can we control and characterize the external shape and crystal structure of such small nanocrystals?'. This feature article aims to give the reader an overview of important techniques, concepts and recent advances related to these questions. Nucleation, growth and how seed crystallography influences the final synthesis product are discussed, followed by shape prediction models based on seed crystallography and thermodynamic or kinetic parameters. The crystallographic implications of epitaxy and orientation in multilayered, core-shell nanoparticles are overviewed, and, finally, the development and implications of novel, spatially resolved analysis tools are discussed.

  10. Crystallization and preliminary crystallographic analysis of recombinant human galectin-1

    Energy Technology Data Exchange (ETDEWEB)

    Scott, Stacy A. [Institute for Glycomics, Gold Coast Campus, Griffith University, Queensland 4222 (Australia); Scott, Ken [School of Biological Sciences, University of Auckland, Auckland (New Zealand); Blanchard, Helen, E-mail: h.blanchard@griffith.edu.au [Institute for Glycomics, Gold Coast Campus, Griffith University, Queensland 4222 (Australia)

    2007-11-01

    Human galectin-1 has been cloned, expressed in E. coli, purified and crystallized in the presence of both lactose (ligand) and β-mercaptoethanol under six different conditions. The X-ray diffraction data obtained have enabled the assignment of unit-cell parameters for two novel crystal forms of human galectin-1. Galectin-1 is considered to be a regulator protein as it is ubiquitously expressed throughout the adult body and is responsible for a broad range of cellular regulatory functions. Interest in galectin-1 from a drug-design perspective is founded on evidence of its overexpression by many cancers and its immunomodulatory properties. The development of galectin-1-specific inhibitors is a rational approach to the fight against cancer because although galectin-1 induces a plethora of effects, null mice appear normal. X-ray crystallographic structure determination will aid the structure-based design of galectin-1 inhibitors. Here, the crystallization and preliminary diffraction analysis of human galectin-1 crystals generated under six different conditions is reported. X-ray diffraction data enabled the assignment of unit-cell parameters for crystals grown under two conditions, one belongs to a tetragonal crystal system and the other was determined as monoclinic P2{sub 1}, representing two new crystal forms of human galectin-1.

  11. Phormidium phycoerythrin forms hexamers in crystals: a crystallographic study.

    Science.gov (United States)

    Sonani, Ravi Raghav; Sharma, Mahima; Gupta, Gagan Deep; Kumar, Vinay; Madamwar, Datta

    2015-08-01

    The crystallographic analysis of a marine cyanobacterium (Phormidium sp. A09DM) phycoerythrin (PE) that shows distinct sequence features compared with known PE structures from cyanobacteria and red algae is reported. Phormidium PE was crystallized using the sitting-drop vapour-diffusion method with ammonium sulfate as a precipitant. Diffraction data were collected on the protein crystallography beamline at the Indus-2 synchrotron. The crystals diffracted to about 2.1 Å resolution at 100 K. The crystals, with an apparent hexagonal morphology, belonged to space group P1, with unit-cell parameters a = 108.3, b = 108.4 Å, c = 116.6 Å, α = 78.94, β = 82.50, γ = 60.34°. The molecular-replacement solution confirmed the presence of 12 αβ monomers in the P1 cell. The Phormidium PE elutes as an (αβ)3 trimer of αβ monomers from a molecular-sieve column and exists as [(αβ)3]2 hexamers in the crystal lattice. Unlike red algal PE proteins, the hexamers of Phormidium PE do not form higher-order structures in the crystals. The existence of only one characteristic visual absorption band at 564 nm suggests the presence of phycoerythrobilin chromophores, and the absence of any other types of bilins, in the Phormidium PE assembly.

  12. Correlating Atom Probe Crystallographic Measurements with Transmission Kikuchi Diffraction Data.

    Science.gov (United States)

    Breen, Andrew J; Babinsky, Katharina; Day, Alec C; Eder, K; Oakman, Connor J; Trimby, Patrick W; Primig, Sophie; Cairney, Julie M; Ringer, Simon P

    2017-03-14

    Correlative microscopy approaches offer synergistic solutions to many research problems. One such combination, that has been studied in limited detail, is the use of atom probe tomography (APT) and transmission Kikuchi diffraction (TKD) on the same tip specimen. By combining these two powerful microscopy techniques, the microstructure of important engineering alloys can be studied in greater detail. For the first time, the accuracy of crystallographic measurements made using APT will be independently verified using TKD. Experimental data from two atom probe tips, one a nanocrystalline Al-0.5Ag alloy specimen collected on a straight flight-path atom probe and the other a high purity Mo specimen collected on a reflectron-fitted instrument, will be compared. We find that the average minimum misorientation angle, calculated from calibrated atom probe reconstructions with two different pole combinations, deviate 0.7° and 1.4°, respectively, from the TKD results. The type of atom probe and experimental conditions appear to have some impact on this accuracy and the reconstruction and measurement procedures are likely to contribute further to degradation in angular resolution. The challenges and implications of this correlative approach will also be discussed.

  13. Nanocrystalline materials: recent advances in crystallographic characterization techniques

    Science.gov (United States)

    Ringe, Emilie

    2014-01-01

    Most properties of nanocrystalline materials are shape-dependent, providing their exquisite tunability in optical, mechanical, electronic and catalytic properties. An example of the former is localized surface plasmon resonance (LSPR), the coherent oscillation of conduction electrons in metals that can be excited by the electric field of light; this resonance frequency is highly dependent on both the size and shape of a nanocrystal. An example of the latter is the marked difference in catalytic activity observed for different Pd nanoparticles. Such examples highlight the importance of particle shape in nanocrystalline materials and their practical applications. However, one may ask ‘how are nanoshapes created?’, ‘how does the shape relate to the atomic packing and crystallography of the material?’, ‘how can we control and characterize the external shape and crystal structure of such small nanocrystals?’. This feature article aims to give the reader an overview of important techniques, concepts and recent advances related to these questions. Nucleation, growth and how seed crystallography influences the final synthesis product are discussed, followed by shape prediction models based on seed crystallography and thermodynamic or kinetic parameters. The crystallographic implications of epitaxy and orientation in multilayered, core-shell nanoparticles are overviewed, and, finally, the development and implications of novel, spatially resolved analysis tools are discussed. PMID:25485133

  14. Reduced Bayesian Inversion

    OpenAIRE

    Himpe, Christian; Ohlberger, Mario

    2014-01-01

    Bayesian inversion of models with large state and parameter spaces proves to be computationally complex. A combined state and parameter reduction can significantly decrease the computational time and cost required for the parameter estimation. The presented technique is based on the well-known balanced truncation approach. Classically, the balancing of the controllability and observability gramians allows a truncation of discardable states. Here the underlying model, being a linear or nonline...

  15. The Fukushima Inverse Problem

    OpenAIRE

    Martinez-Camara, Marta; Dokmanic, Ivan; Ranieri, Juri; Scheibler, Robin; Vetterli, Martin; STOHL Andreas

    2013-01-01

    Knowing what amount of radioactive material was released from Fukushima in March 2011 and at what time instants is crucial to assess the risk, the pollution, and to understand the scope of the consequences. Moreover, it could be used in forward simulations to obtain accurate maps of deposition. But these data are often not publicly available. We propose to estimate the emission waveforms by solving an inverse problem. Previous approaches have relied on a detailed expert guess of how the relea...

  16. [Total inversion of the uterus].

    Science.gov (United States)

    Novachkov, V; Baltadzhieva, B; Ilieva, A; Rachev, E

    2008-01-01

    Non puerperal inversion of the uterus is very uncommon. Patients may present with pelvic pain, vaginal bleeding or hemodynamic shock. We report a fifty five old woman with uterus inversion second stage.

  17. The emergence of urban centres

    DEFF Research Database (Denmark)

    Lazaro, Evelyn; Agergaard, Jytte; Larsen, Marianne Nylandsted

    In this paper we aim at understanding how social and spatial transformation of dynamic rural regions is driving spatial concentration and urbanization. We are particularly concerned with the processes of spatial change, verbalized as the emergence of urban centres in rural areas. Emerging Urban...... Centres (EUCs) are characterized by rapid population growth related to continuous and diverse flows of migrants from rural hinterlands and more detached rural locations. Many of these centres are also characterized by economic dynamics related to agricultural sector activities that have been stimulated...... by Tanzanian market liberalizations and its long term effects on private enterprise. The paper is based on a study of four EUCs in Tanzania (Ilula, Igowole, Madizini and Kibaigwa) and seeks to answer three research questions: 1) What economic and spatial trends, including national policies, have formed...

  18. Person-centred reflective practice.

    Science.gov (United States)

    Devenny, Bob; Duffy, Kathleen

    Person-centred health and person-centred care have gained prominence across the UK following the publication of reports on public inquiries exploring failings in care. Self-awareness and participation in reflective practice are recognised as vital to supporting the person-centred agenda. This article presents an education framework for reflective practice, developed and used in one NHS board in Scotland, and based on the tenets of the clinical pastoral education movement. Providing an insight into the usefulness of a spiritual component in the reflective process, the framework provides an opportunity for nurses and other healthcare professionals to examine the spiritual dimensions of patient encounters, their own values and beliefs, and the effect these may have on their practice.

  19. Construction of the Wigner Data Centre

    CERN Multimedia

    2013-01-01

    A remote extension of the CERN data centre has recently been inaugurated. Hosted at the Wigner Research Centre for Physics in Hungary, it provides extra computing power required to cover CERN’s needs. This video presents the construction of the Wigner Data Centre from initial demolishing work through to its completion and details the major technical characteristics of the Data Centre.

  20. Construction of the Wigner Data Centre

    CERN Document Server

    2013-01-01

    A remote extension of the CERN data centre has recently been inaugurated. Hosted at the Wigner Research Centre for Physics in Hungary, it provides extra computing power required to cover CERN’s needs. This video presents the construction of the Wigner Data Centre from initial demolishing work through to its completion and details the major technical characteristics of the Data Centre.

  1. Patterning hierarchy in direct and inverse opal crystals.

    Science.gov (United States)

    Mishchenko, Lidiya; Hatton, Benjamin; Kolle, Mathias; Aizenberg, Joanna

    2012-06-25

    Biological strategies for bottom-up synthesis of inorganic crystalline and amorphous materials within topographic templates have recently become an attractive approach for fabricating complex synthetic structures. Inspired by these strategies, herein the synthesis of multi-layered, hierarchical inverse colloidal crystal films formed directly on topographically patterned substrates via evaporative deposition, or "co-assembly", of polymeric spheres with a silicate sol-gel precursor solution and subsequent removal of the colloidal template, is described. The response of this growing composite colloid-silica system to artificially imposed 3D spatial constraints of various geometries is systematically studied, and compared with that of direct colloidal crystal assembly on the same template. Substrates designed with arrays of rectangular, triangular, and hexagonal prisms and cylinders are shown to control crystallographic domain nucleation and orientation of the direct and inverse opals. With this bottom-up topographical approach, it is demonstrated that the system can be manipulated to either form large patterned single crystals, or crystals with a fine-tuned extent of disorder, and to nucleate distinct colloidal domains of a defined size, location, and orientation in a wide range of length-scales. The resulting ordered, quasi-ordered, and disordered colloidal crystal films show distinct optical properties. Therefore, this method provides a means of controlling bottom-up synthesis of complex, hierarchical direct and inverse opal structures designed for altering optical properties and increased functionality. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Scheduling participants of Assessment Centres

    DEFF Research Database (Denmark)

    Lysgaard, Jens; Løber, Janni

      Assessment Centres are used as a tool for psychologists and coaches to observe a number of dimensions in a person's behaviour and test his/her potential within a number of chosen focus areas. This is done in an intense course, with a number of different exercises which expose each participant...... Centres usually last two days and involve 3-6 psychologists or trained coaches as assessors. An entire course is composed of a number of rounds, with each round having its individual duration. In each round, the participants are divided into a number of groups with prespecifed pairing of group sizes...

  3. Human Centred Design: a bibliometric overview based on Science Direct

    OpenAIRE

    Lucas José Garcia; Giselle Schmidt Alves Díaz Merino; Susana Cristina Domenech; Eugenio Andres Díaz Merino; Adilson Luiz Pinto

    2016-01-01

    This article aims to realize a bibliometric review on Science Direct to create a outlook about Human Centred Design in order to identify the most significant authors, journals and key-words as well as the most recurrent denomination about the subject. The method employed consist of application of three classical bibliometric laws: the Inverse Square Law of Lotka; the Bradford’s Law of Scattering and; The frequency law of words in a text of Zipf. The results indicate that the subject is not a ...

  4. Variations in Reactivity on Different Crystallographic Orientations of Cerium Oxide

    Energy Technology Data Exchange (ETDEWEB)

    Mullins, David R [ORNL; Albrecht, Peter M [ORNL; Calaza, Florencia C [ORNL

    2013-01-01

    Cerium oxide is a principal component in many heterogeneous catalytic processes. One of its key characteristics is the ability to provide or remove oxygen in chemical reactions. The different crystallographic faces of ceria present significantly different surface structures and compositions that may alter the catalytic reactivity. The structure and composition determine the number of coordination vacancies surrounding surface atoms, the availability of adsorption sites, the spacing between adsorption sites and the ability to remove O from the surface. To investigate the role of surface orientation on reactivity, CeO2 films were grown with two different orientations. CeO2(100) films were grown ex situ by pulsed laser deposition on Nb-doped SrTiO3(100). CeO2(111) films were grown in situ by thermal deposition of Ce metal onto Ru(0001) in an oxygen atmosphere. The chemical reactivity was characterized by the adsorption and decomposition of various molecules such as alcohols, aldehydes and organic acids. In general the CeO2(100) surface was found to be more active, i.e. molecules adsorbed more readily and reacted to form new products, especially on a fully oxidized substrate. However the CeO2(100) surface was less selective with a greater propensity to produce CO, CO2 and water as products. The differences in chemical reactivity are discussed in light of possible structural terminations of the two surfaces. Recently nanocubes and nano-octahedra have been synthesized that display CeO2(100) and CeO2(111) faces, respectively. These nanoparticles enable us to correlate reactions on high surface area model catalysts at atmospheric pressure with model single crystal films in a UHV environment.

  5. Shape and crystallographic orientation of nanodiamonds for quantum sensing.

    Science.gov (United States)

    Ong, S Y; Chipaux, M; Nagl, A; Schirhagl, R

    2017-01-23

    Nanodiamonds with dimensions down to a few tens of nanometers containing nitrogen-vacancy (NV) color centers have revealed their potential as powerful and versatile quantum sensors with a unique combination of spatial resolution and sensitivity. The NV centers allow transducing physical properties, such as strain, temperature, and electric or magnetic field, to an optical transition that can be detected in the single photon range. For example, this makes it possible to sense a single electron spin or a few nuclear spins by detecting their magnetic resonance. The location and orientation of these defects with respect to the diamond surface play a crucial role in interpreting the data and predicting their sensitivities. Despite its relevance, the geometry of these nanodiamonds has never been thoroughly investigated. Without accurate data, spherical models have been applied to interpret or predict results in the past. With the use of High Resolution Transmission Electron Microscopy (HR-TEM), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM), we investigated nanodiamonds with an average hydrodynamic diameter of 25 nm (the most common type for quantum sensing) and found a flake-like geometry, with 23.2 nm and 4.5 nm being the average lateral and vertical dimensions. We have also found evidence for a preferred crystallographic orientation of the main facet in the (110) direction. Furthermore, we discuss the consequences of this difference in geometry on diamond-based applications. Shape not only influences the creation efficiency of nitrogen-vacancy centers and their quantum coherence properties (and thus sensing performance), but also the optical properties of the nanodiamonds, their interaction with living cells, and their surface chemistry.

  6. Calculation of Crystallographic Texture of BCC Steels During Cold Rolling

    Science.gov (United States)

    Das, Arpan

    2017-05-01

    BCC alloys commonly tend to develop strong fibre textures and often represent as isointensity diagrams in φ 1 sections or by fibre diagrams. Alpha fibre in bcc steels is generally characterised by crystallographic axis parallel to the rolling direction. The objective of present research is to correlate carbon content, carbide dispersion, rolling reduction, Euler angles (ϕ) (when φ 1 = 0° and φ 2 = 45° along alpha fibre) and the resulting alpha fibre texture orientation intensity. In the present research, Bayesian neural computation has been employed to correlate these and compare with the existing feed-forward neural network model comprehensively. Excellent match to the measured texture data within the bounding box of texture training data set has been already predicted through the feed-forward neural network model by other researchers. Feed-forward neural network prediction outside the bounds of training texture data showed deviations from the expected values. Currently, Bayesian computation has been similarly applied to confirm that the predictions are reasonable in the context of basic metallurgical principles, and matched better outside the bounds of training texture data set than the reported feed-forward neural network. Bayesian computation puts error bars on predicted values and allows significance of each individual parameters to be estimated. Additionally, it is also possible by Bayesian computation to estimate the isolated influence of particular variable such as carbon concentration, which exactly cannot in practice be varied independently. This shows the ability of the Bayesian neural network to examine the new phenomenon in situations where the data cannot be accessed through experiments.

  7. Crystallographic control on the substructure of nacre tablets.

    Science.gov (United States)

    Checa, Antonio G; Mutvei, Harry; Osuna-Mascaró, Antonio J; Bonarski, Jan T; Faryna, Marek; Berent, Katarzyna; Pina, Carlos M; Rousseau, Marthe; Macías-Sánchez, Elena

    2013-09-01

    Nacre tablets of mollusks develop two kinds of features when either the calcium carbonate or the organic portions are removed: (1) parallel lineations (vermiculations) formed by elongated carbonate rods, and (2) hourglass patterns, which appear in high relief when etched or in low relief if bleached. In untreated tablets, SEM and AFM data show that vermiculations correspond to aligned and fused aragonite nanogloblules, which are partly surrounded by thin organic pellicles. EBSD mapping of the surfaces of tablets indicates that the vermiculations are invariably parallel to the crystallographic a-axis of aragonite and that the triangles are aligned with the b-axis and correspond to the advance of the {010} faces during the growth of the tablet. According to our interpretation, the vermiculations appear because organic molecules during growth are expelled from the a-axis, where the Ca-CO3 bonds are the shortest. In this way, the subunits forming nacre merge uninterruptedly, forming chains parallel to the a-axis, whereas the organic molecules are expelled to the sides of these chains. Hourglass patterns would be produced by preferential adsorption of organic molecules along the {010}, as compared to the {100} faces. A model is presented for the nanostructure of nacre tablets. SEM and EBSD data also show the existence within the tablets of nanocrystalline units, which are twinned on {110} with the rest of the tablet. Our study shows that the growth dynamics of nacre tablets (and bioaragonite in general) results from the interaction at two different and mutually related levels: tablets and nanogranules.

  8. Inversion assuming weak scattering

    DEFF Research Database (Denmark)

    Xenaki, Angeliki; Gerstoft, Peter; Mosegaard, Klaus

    2013-01-01

    The study of weak scattering from inhomogeneous media or interface roughness has long been of interest in sonar applications. In an acoustic backscattering model of a stationary field of volume inhomogeneities, a stochastic description of the field is more useful than a deterministic description...... due to the complex nature of the field. A method based on linear inversion is employed to infer information about the statistical properties of the scattering field from the obtained cross-spectral matrix. A synthetic example based on an active high-frequency sonar demonstrates that the proposed...

  9. Inverse Degree and Connectivity

    Institute of Scientific and Technical Information of China (English)

    MA Xiao-ling; TIAN Ying-zhi

    2013-01-01

    Let G be a connected graph with vertex set V(G),order n =丨V(G)丨,minimum degree δ(G) and connectivity κ(G).The graph G is called maximally connected if κ(G) =δ(G).Define the inverse degree of G with no isolated vertices as R(G) =Σv∈V(G)1/d(v),where d(v) denotes the degree of the vertex v.We show that G is maximally connected if R(G) < 1 + 2/δ + n-2δ+1/(n-1)(n-3).

  10. LDE centres: sprint or marathon?

    NARCIS (Netherlands)

    Bonger, S.; Van Rein, E.

    2015-01-01

    The aim of the Strategic Leiden-Delft-Erasmus Alliance, established by the three universities in 2012, was to improve research and education and competitiveness. Projects are intended to develop from the ground up, which led to the establishment of eight joint centres in 2013. A quick look around re

  11. SISYPHUS: A high performance seismic inversion factory

    Science.gov (United States)

    Gokhberg, Alexey; Simutė, Saulė; Boehm, Christian; Fichtner, Andreas

    2016-04-01

    branches for the static process setup, inversion iterations, and solver runs, each branch specifying information at the event, station and channel levels. The workflow management framework is based on an embedded scripting engine that allows definition of various workflow scenarios using a high-level scripting language and provides access to all available inversion components represented as standard library functions. At present the SES3D wave propagation solver is integrated in the solution; the work is in progress for interfacing with SPECFEM3D. A separate framework is designed for interoperability with an optimization module; the workflow manager and optimization process run in parallel and cooperate by exchanging messages according to a specially designed protocol. A library of high-performance modules implementing signal pre-processing, misfit and adjoint computations according to established good practices is included. Monitoring is based on information stored in the inversion state database and at present implements a command line interface; design of a graphical user interface is in progress. The software design fits well into the common massively parallel system architecture featuring a large number of computational nodes running distributed applications under control of batch-oriented resource managers. The solution prototype has been implemented on the "Piz Daint" supercomputer provided by the Swiss Supercomputing Centre (CSCS).

  12. The CCCB is a cultural centre, not a tourist centre

    Directory of Open Access Journals (Sweden)

    Elena Xirau

    2004-04-01

    Full Text Available Last February, Barcelona's Centre of Contemporary Culture (CCCB celebrated its first ten years in existence. During this time, this institution has looked to be a showcase to the most modern and innovative cultural expressions focused on reflecting on the concept of the city. In this interview, Josep Ramoneda offers his personal view, as the CCCB's director. He talks of how this cultural project was born, of how the concept of the institution took shape in the CCCB, of its relations with Barcelona's Strategic Plan, of how the project has evolved, of the architectural remodelling of the Casa de la Caritat building for its conversion into a cultural centre, of the relations with other institutions and its future.

  13. Energetic, crystallographic and diffusion characteristics of hydrogen isotopes in iron

    Energy Technology Data Exchange (ETDEWEB)

    Sivak, A.B., E-mail: sivak_ab@nrcki.ru [National Research Centre “Kurchatov Institute”, 1, Akademika Kurchatova pl., Moscow 123182 (Russian Federation); National Research Tomsk State University, 36, Lenina pr., Tomsk 634050 (Russian Federation); Sivak, P.A., E-mail: sivak_pa@nrcki.ru [National Research Centre “Kurchatov Institute”, 1, Akademika Kurchatova pl., Moscow 123182 (Russian Federation); Romanov, V.A., E-mail: romanov-ippe@mail.ru [National Research Tomsk State University, 36, Lenina pr., Tomsk 634050 (Russian Federation); A.I. Leypunski Institute of Physics and Power Engineering (IPPE), 1, Bondarenko pl., Obninsk, Kaluga reg. 249033 (Russian Federation); Chernov, V.M., E-mail: vmchernov@bochvar.ru [National Research Tomsk State University, 36, Lenina pr., Tomsk 634050 (Russian Federation); A.A. Bochvar High-technology Research Institute of Inorganic Materials (JSC “VNIINM”), 5-a, Rogova ul., PoB 369, Moscow 123098 (Russian Federation); National Research Nuclear University “MEPhI”, 31, Kashirskoye sh., Moscow 115409 (Russian Federation)

    2015-06-15

    Highlights: • H isotopes properties in Fe were calculated by molecular statics and dynamics methods. • The binding energies of complexes “H atoms – self-defects” were calculated. • Temperature dependencies of H isotopes diffusivities have parabolic form at T > 250 K. • There is a good agreement between MD and experimental data for protium diffusivity. • H isotopes diffusivities are within 10% at 293 K. Isotope effect increases with temperature. - Abstract: Energetic, crystallographic and diffusion characteristics of various interstitial configurations of H atoms and their complexes with self-point defects (SIA – self-interstitial atom, V – vacancy) in bcc iron have been calculated by molecular statics and molecular dynamics using Fe–H interatomic interaction potential developed by Ramasubramaniam et al. (2009) and modified by the authors of the present work and Fe–Fe matrix potential M07 developed by Malerba et al. (2010). The most energetically favorable configuration of an interstitial H atom is tetrahedral configuration. The energy barrier for H atom migration is 0.04 eV. The highest binding energy of all the considered complexes “vacancy – H atom” and “SIA – H atom” is 0.54 and 0.15 eV, respectively. The binding energy of H atom with edge dislocations in slip systems 〈1 1 1〉{1 1 0}, 〈1 1 1〉{1 1 2}, 〈1 0 0〉{1 0 0}, 〈1 0 0〉{1 1 0} is 0.32, 0.30, 0.45, 0.54 eV, respectively. The binding energy of H atom in VH{sub n} complexes (n = 1 … 15) decreases from 0.54 to 0.35 eV with increasing of n from 1 to 6. At n > 6, it decreases to ∼0.1 eV. The temperature dependences of hydrogen isotopes (P, D, T) diffusivities have been calculated for the temperature range 70–1800 K. Arrhenius-type dependencies describe the calculated data at temperatures T < 100 K. At T > 250 K, the temperature dependencies of the diffusivities D{sup P}, D{sup D}, D{sup T} have a parabolic form. The diffusivities of H isotopes are within 10

  14. Crystallographic transformation of limestone during calcination under CO2.

    Science.gov (United States)

    Valverde, Jose Manuel; Medina, Santiago

    2015-09-14

    The calcination reaction of limestone (CaCO3) to yield lime (CaO) is at the heart of many industrial applications as well as natural processes. In the recently emerged calcium-looping technology, CO2 capture is accomplished by the carbonation of CaO in a gas-solid reactor (carbonator). CaO is derived by the calcination of limestone in a calciner reactor under necessarily high CO2 partial pressure and high temperature. In situ X-ray diffraction (XRD) has been employed in this work to gain further insight into the crystallographic transformation that takes place during the calcination of limestone under CO2, at partial pressures (P) close to the equilibrium pressure (Peq) and at high temperature. Calcination under these conditions becomes extremely slow. The in situ XRD analysis presented here suggests the presence of an intermediate metastable CaO* phase stemming from the parent CaCO3 structure. According to the reaction mechanism proposed elsewhere, the exothermicity of the CaO* → CaO transformation and high values of P/Peq inhibit the nucleation of CaO at high temperatures. The wt% of CaO* remains at a relatively high level during slow calcination. Two diverse stages have been identified in the evolution of CaO crystallite size, L. Initially, L increases with CaCO3 conversion, following a logarithmic law. Slow calcination allows the crystallite size to grow up from a few nanometers at nucleation up to around 100 nm near the end of conversion. Otherwise, quick calcination at relatively lower CO2 concentrations limits CaO crystallite growth. Once calcination reaches an advanced state, the presence of CaO* drops to zero and the rate of increase of the CaO crystallite size is significantly hindered. Arguably, the first stage in CaO crystallite growth is driven by aggregation of the metastable CaO* nanocrystals, due to surface attractive forces, whereas the second one is consistent with sintering of the aggregated CaO crystals, and persists with time after full

  15. Dark Radiative Inverse Seesaw

    CERN Document Server

    Ahriche, Amine; Nasri, Salah

    2016-01-01

    We present a minimal model that simultaneously accounts for neutrino masses and the origin of dark matter (DM) and where the electroweak phase transition is strong enough to allow for electroweak baryogenesis. The Standard Model is enlarged with a Majorana fermion, three generations of chiral fermion pairs, and a single complex scalar that plays a central role in DM production and phenomenology, neutrino masses, and the strength of the phase transition. All the new fields are singlets under the SM gauge group. Neutrino masses are generated via a new variant of radiative inverse seesaw where the required small mass term is generated via loops involving DM and no large hierarchy is assumed among the mass scales. The model offers all the advantage of low-scale neutrino mass models as well as a viable dark matter candidate that is testable with direct detection experiments.

  16. Inverse Queries For Multidimensional Spaces

    CERN Document Server

    Bernecker, Thomas; Kriegel, Hans-Peter; Mamoulis, Nikos; Renz, Matthias; Zhang, Shiming; Züfle, Andreas

    2011-01-01

    Traditional spatial queries return, for a given query object $q$, all database objects that satisfy a given predicate, such as epsilon range and $k$-nearest neighbors. This paper defines and studies {\\em inverse} spatial queries, which, given a subset of database objects $Q$ and a query predicate, return all objects which, if used as query objects with the predicate, contain $Q$ in their result. We first show a straightforward solution for answering inverse spatial queries for any query predicate. Then, we propose a filter-and-refinement framework that can be used to improve efficiency. We show how to apply this framework on a variety of inverse queries, using appropriate space pruning strategies. In particular, we propose solutions for inverse epsilon range queries, inverse $k$-nearest neighbor queries, and inverse skyline queries. Our experiments show that our framework is significantly more efficient than naive approaches.

  17. European Centre for Disease Prevention and Control.

    Science.gov (United States)

    Evans, Roger

    2014-11-04

    The European Centre for Disease Prevention and Control was set up in 2005 to strengthen Europe's defences against infectious diseases. The centre is an independent agency of the European Union and is based in Stockholm, Sweden.

  18. LABORATORY SERVICES IN HEALTH CENTRES WITHIN ...

    African Journals Online (AJOL)

    1999-05-05

    May 5, 1999 ... the technicians aimed at improving the services in health centres within ... Settings: Twenty seven health centres in Amhara region, north .... man power in the laboratory .... service consumption in a teaching hospital in Gondar,.

  19. Approximation Theorems of Moore-Penrose Inverse by Outer Inverses

    Institute of Scientific and Technical Information of China (English)

    Qianglian Huang; Zheng Fang

    2006-01-01

    Let X and Y be Hilbert spaces and T a bounded linear operator from X into Y with a separable range. In this note, we prove, without assuming the closeness of the range of T, that the Moore-Penrose inverse T+ of T can be approximated by its bounded outer inverses T#n with finite ranks.

  20. Communicating astronomy by the Unizul Science Centre

    Science.gov (United States)

    Beesham, A.; Beesham, N.

    2015-03-01

    The University of Zululand, situated along the east coast of KwaZulu-Natal, has a thriving Science Centre (USC) situated in the developing port city of Richards Bay. Over 30 000 learners visit the centre annually, and it consists of an exhibition area, an auditorium, lecture areas and offices. The shows consist of interactive games, science shows, competitions, quizzes and matriculation workshops. Outreach activities take place through a mobile science centre for schools and communities that cannot visit the centre.

  1. A log-likelihood-gain intensity target for crystallographic phasing that accounts for experimental error.

    Science.gov (United States)

    Read, Randy J; McCoy, Airlie J

    2016-03-01

    The crystallographic diffraction experiment measures Bragg intensities; crystallographic electron-density maps and other crystallographic calculations in phasing require structure-factor amplitudes. If data were measured with no errors, the structure-factor amplitudes would be trivially proportional to the square roots of the intensities. When the experimental errors are large, and especially when random errors yield negative net intensities, the conversion of intensities and their error estimates into amplitudes and associated error estimates becomes nontrivial. Although this problem has been addressed intermittently in the history of crystallographic phasing, current approaches to accounting for experimental errors in macromolecular crystallography have numerous significant defects. These have been addressed with the formulation of LLGI, a log-likelihood-gain function in terms of the Bragg intensities and their associated experimental error estimates. LLGI has the correct asymptotic behaviour for data with large experimental error, appropriately downweighting these reflections without introducing bias. LLGI abrogates the need for the conversion of intensity data to amplitudes, which is usually performed with the French and Wilson method [French & Wilson (1978), Acta Cryst. A35, 517-525], wherever likelihood target functions are required. It has general applicability for a wide variety of algorithms in macromolecular crystallography, including scaling, characterizing anisotropy and translational noncrystallographic symmetry, detecting outliers, experimental phasing, molecular replacement and refinement. Because it is impossible to reliably recover the original intensity data from amplitudes, it is suggested that crystallographers should always deposit the intensity data in the Protein Data Bank.

  2. Small Steps towards Student-Centred Learning

    Science.gov (United States)

    Jacobs, George M.; Toh-Heng, Hwee Leng

    2013-01-01

    Student centred learning classroom practices are contrasted with those in teacher centred learning classrooms. The discussion focuses on the theoretical underpinnings of the former, and provides nine steps and tips on how to implement student centred learning strategies, with the aim of developing the 21st century skills of self-directed and…

  3. Magnetic anisotropy induced by crystallographic orientation and morphological alignment in directionally-solidified eutectic Mn-Sb alloy

    Science.gov (United States)

    Lou, Chang-Sheng; Liu, Tie; Dong, Meng; Wu, Chun; Shao, Jian-Guo; Wang, Qiang

    2017-02-01

    The influences of the crystallographic orientation and morphological alignment upon the magnetic anisotropic behavior of polycrystalline materials were investigated. Microstructures obtained in eutectic Mn-Sb alloys via directional solidification simultaneously displayed crystallographic orientation and morphological alignment. Both the crystallographic orientation and the morphological alignment were able to induce magnetic anisotropy in the alloys, wherein the influence of the crystallographic orientation and the morphological alignment upon the magnetic anisotropic behavior of the alloys strongly depended upon their directions and exhibited either mutual promotion or competition. These findings may provide useful guidance for the fabrication design of functional magnetic materials.

  4. Multiples waveform inversion

    KAUST Repository

    Zhang, D. L.

    2013-01-01

    To increase the illumination of the subsurface and to eliminate the dependency of FWI on the source wavelet, we propose multiples waveform inversion (MWI) that transforms each hydrophone into a virtual point source with a time history equal to that of the recorded data. These virtual sources are used to numerically generate downgoing wavefields that are correlated with the backprojected surface-related multiples to give the migration image. Since the recorded data are treated as the virtual sources, knowledge of the source wavelet is not required, and the subsurface illumination is greatly enhanced because the entire free surface acts as an extended source compared to the radiation pattern of a traditional point source. Numerical tests on the Marmousi2 model show that the convergence rate and the spatial resolution of MWI is, respectively, faster and more accurate then FWI. The potential pitfall with this method is that the multiples undergo more than one roundtrip to the surface, which increases attenuation and reduces spatial resolution. This can lead to less resolved tomograms compared to conventional FWI. The possible solution is to combine both FWI and MWI in inverting for the subsurface velocity distribution.

  5. Inverse problem in hydrogeology

    Science.gov (United States)

    Carrera, Jesús; Alcolea, Andrés; Medina, Agustín; Hidalgo, Juan; Slooten, Luit J.

    2005-03-01

    The state of the groundwater inverse problem is synthesized. Emphasis is placed on aquifer characterization, where modelers have to deal with conceptual model uncertainty (notably spatial and temporal variability), scale dependence, many types of unknown parameters (transmissivity, recharge, boundary conditions, etc.), nonlinearity, and often low sensitivity of state variables (typically heads and concentrations) to aquifer properties. Because of these difficulties, calibration cannot be separated from the modeling process, as it is sometimes done in other fields. Instead, it should be viewed as one step in the process of understanding aquifer behavior. In fact, it is shown that actual parameter estimation methods do not differ from each other in the essence, though they may differ in the computational details. It is argued that there is ample room for improvement in groundwater inversion: development of user-friendly codes, accommodation of variability through geostatistics, incorporation of geological information and different types of data (temperature, occurrence and concentration of isotopes, age, etc.), proper accounting of uncertainty, etc. Despite this, even with existing codes, automatic calibration facilitates enormously the task of modeling. Therefore, it is contended that its use should become standard practice. L'état du problème inverse des eaux souterraines est synthétisé. L'accent est placé sur la caractérisation de l'aquifère, où les modélisateurs doivent jouer avec l'incertitude des modèles conceptuels (notamment la variabilité spatiale et temporelle), les facteurs d'échelle, plusieurs inconnues sur différents paramètres (transmissivité, recharge, conditions aux limites, etc.), la non linéarité, et souvent la sensibilité de plusieurs variables d'état (charges hydrauliques, concentrations) des propriétés de l'aquifère. A cause de ces difficultés, le calibrage ne peut êtreséparé du processus de modélisation, comme c'est le

  6. Inverse problems for Maxwell's equations

    CERN Document Server

    Romanov, V G

    1994-01-01

    The Inverse and Ill-Posed Problems Series is a series of monographs publishing postgraduate level information on inverse and ill-posed problems for an international readership of professional scientists and researchers. The series aims to publish works which involve both theory and applications in, e.g., physics, medicine, geophysics, acoustics, electrodynamics, tomography, and ecology.

  7. Inversion exercises inspired by mechanics

    Science.gov (United States)

    Groetsch, C. W.

    2016-02-01

    An elementary calculus transform, inspired by the centroid and gyration radius, is introduced as a prelude to the study of more advanced transforms. Analysis of the transform, including its inversion, makes use of several key concepts from basic calculus and exercises in the application and inversion of the transform provide practice in the use of technology in calculus.

  8. Experimental and Theoretical Investigation of Crystallographic Orientation Dependence of Nanoscratching of Single Crystalline Copper

    Science.gov (United States)

    Geng, Yanquan; Zhang, Junjie; Yan, Yongda; Yu, Bowen; Geng, Lin; Sun, Tao

    2015-01-01

    In the present work, we perform experiments and molecular dynamics simulations to elucidate the underlying deformation mechanisms of single crystalline copper under the load-controlled multi-passes nanoscratching using a triangular pyramidal probe. The correlation of microscopic deformation behavior of the material with macroscopically-observed machining results is revealed. Moreover, the influence of crystallographic orientation on the nanoscratching of single crystalline copper is examined. Our simulation results indicate that the plastic deformation of single crystalline Cu under the nanoscratching is exclusively governed by dislocation mechanisms. However, there is no glissile dislocation structure formed due to the probe oscillation under the load-controlled mode. Both experiments and MD simulations demonstrate that the machined surface morphologies in terms of groove depth and surface pile-up exhibit strong crystallographic orientation dependence, because of different geometries of activated slip planes cutting with free surfaces and strain hardening abilities associated with different crystallographic orientations. PMID:26147506

  9. Experimental and Theoretical Investigation of Crystallographic Orientation Dependence of Nanoscratching of Single Crystalline Copper.

    Directory of Open Access Journals (Sweden)

    Yanquan Geng

    Full Text Available In the present work, we perform experiments and molecular dynamics simulations to elucidate the underlying deformation mechanisms of single crystalline copper under the load-controlled multi-passes nanoscratching using a triangular pyramidal probe. The correlation of microscopic deformation behavior of the material with macroscopically-observed machining results is revealed. Moreover, the influence of crystallographic orientation on the nanoscratching of single crystalline copper is examined. Our simulation results indicate that the plastic deformation of single crystalline Cu under the nanoscratching is exclusively governed by dislocation mechanisms. However, there is no glissile dislocation structure formed due to the probe oscillation under the load-controlled mode. Both experiments and MD simulations demonstrate that the machined surface morphologies in terms of groove depth and surface pile-up exhibit strong crystallographic orientation dependence, because of different geometries of activated slip planes cutting with free surfaces and strain hardening abilities associated with different crystallographic orientations.

  10. Evolution of the preferred crystallographic orientation across the thickness of nickel electrodeposits

    DEFF Research Database (Denmark)

    Alimadadi, Hossein; da Silva Fanta, Alice Bastos; Somers, Marcel A. J.;

    Numerous industrial applications of nickel electrodeposits, like for example as microcomponents, essentially depend on their preferred crystallographic orientation. As a function of the electrodeposition conditions, the microstructure can be tailored with respect to the size, shape...... for such advanced investigations. The present work reports on the evolution of the preferred crystallographic orientation on the example of various fiber textured nickel electrodeposits. Tailored electrodeposition provided nickel deposits with different fibre textures being , , and ... and crystallographic orientation of grains. Thorough microstructure characterization, however, is not straightforward, because the microstructure of electrodeposits often changes across the thickness of the deposits and numerous twin orientations even with nano-size dimensions can evolve during growth of the deposits...

  11. Advanced yield strength of interconnector ribbon for photovoltaic module using crystallographic texture control

    Science.gov (United States)

    Kang, Byungjun; Park, Nochang; Tark, Sung Ju; Oh, Won Wook; Park, Sungeun; Kim, Young Do; Lee, Hae-Seok; Kim, Donghwan

    2014-03-01

    This paper reports a study on reducing the yield strength of Cu ribbon wire used for Si solar cell interconnections in solar panels. Low yield strength Cu core should be used as the interconnector ribbon to minimize the fracture of Si solar cells during the tabbing process. We lowered the yield strength of Cu ribbon by controlling the crystallographic texture without increasing the annealing time and temperature. The crystallographic texture was controlled by lubrication in a cold rolling process. The crystallographic texture was observed by scanning electron microscopy with electron back scattered diffraction. A tensile test was performed for the comparison of the mechanical properties of Cu with and without lubrication. The average yield strength was 91.2 MPa with lubrication whereas the yield strength was 99.6 MPa without lubrication. The lower value of the lubricated samples seemed to be caused by the higher cube texture intensity than that of the samples without lubrication.

  12. Student-Centred and Teacher-Centred Learning Environments: What Students Think

    Science.gov (United States)

    Elen, Jan; Clarebout, Geraldine; Leonard, Rebecca; Lowyck, Joost

    2007-01-01

    This contribution explores the relationship between teacher-centred and student-centred learning environments from a student's perspective. Three different views with respect to this relationship can be retrieved. The "balance" view suggests that the more teacher-centred a learning environment is, the less student-centred it is and vice versa. The…

  13. Multiscale Modelling and Inverse Problems

    CERN Document Server

    Nolen, J; Stuart, A M

    2010-01-01

    The need to blend observational data and mathematical models arises in many applications and leads naturally to inverse problems. Parameters appearing in the model, such as constitutive tensors, initial conditions, boundary conditions, and forcing can be estimated on the basis of observed data. The resulting inverse problems are often ill-posed and some form of regularization is required. These notes discuss parameter estimation in situations where the unknown parameters vary across multiple scales. We illustrate the main ideas using a simple model for groundwater flow. We will highlight various approaches to regularization for inverse problems, including Tikhonov and Bayesian methods. We illustrate three ideas that arise when considering inverse problems in the multiscale context. The first idea is that the choice of space or set in which to seek the solution to the inverse problem is intimately related to whether a homogenized or full multiscale solution is required. This is a choice of regularization. The ...

  14. Powering the Future Data Centre

    DEFF Research Database (Denmark)

    Zhang, Zhe

    2010-01-01

    The extended run Uninterruptible Power Supply system (UPSs) which powered by fuel cells and supercapcitors, is a promising solution for future data centre to obtain environmentfriendly energy efficient and cost effective. There are many challenges in power electronic interface circuits, because...... of the traditional cascaded converters, a novel hybrid bidirectional dcdc converter which combines a fuel cell with a boost-type half bridge converter, and supercaps with a DAB converter, is proposed. With phase-shift plus duty cycle, all the switches realize ZVS in a wide range of load variation. Duty cycle control...

  15. Neighbourhood Centres – Organisation, Management and Finance

    DEFF Research Database (Denmark)

    Larsen, Jacob Norvig

    public subsidy. Some of the centres have high number of users on a daily basis, whereas others are only rarely used. It is explored how organisation, management and financial set-up differs among the centres. Quantitative data on financial issues and annual accounts of fifteen centres were analysed......From the late 1990s neighbourhood centres were brought to the fore of public urban regen-eration policy, because they were seen as a means to accelerate the formation of social capital in deprived urban neighbourhoods. A number of such local community centres were established with substantial...... to identify different financial models and analyse economic sustainability. As regards organisational and management models data were collected through documentary sources and by means of personal interviews and field visits to ten centres. Even within the analysed limited population of centres economic...

  16. The Ultrasonic Measurement of Crystallographic Orientation for Imaging Anisotropic Components with 2d Arrays

    Science.gov (United States)

    Lane, C. J. L.; Dunhill, A. K.; Drinkwater, B. W.; Wilcox, P. D.

    2011-06-01

    Single crystal components are used widely in the gas-turbine industry. However, these components are elastically anisotropic which causes difficulties when performing NDE inspections with ultrasound. Recently an ultrasonic algorithm for a 2D array has been corrected to perform the reliable volumetric inspection of single crystals. For the algorithm to be implemented the crystallographic orientation of the components must be known. This paper, therefore, develops and reviews crystallographic orientation methods using 2D ultrasonic arrays. The methods under examination are based on the anisotropic propagation of surface and bulk waves and an image-based orientation method is also considered.

  17. Elasto-Plastic Behavior of High RRR Niobium: Effects of Crystallographic Texture, Microstructure and Hydrogen Concentration

    Energy Technology Data Exchange (ETDEWEB)

    G.R. Myneni; S.R. Agnew

    2002-11-01

    Conventional assessments of the mechanical properties of polycrystalline high RRR niobium via tensile testing have revealed unusually low apparent Young's moduli and yield strength in annealed samples. These observations motivated the current investigation of a variety of possible contributors: crystallographic texture, grain size, and impurity concentration. It is shown that the crystallographic textures of a single lot of niobium are essentially unchanged by post-recrystallization anneals at temperatures up to 800 C. Ultrasonic measurements reveal that the elastic response is not degraded by annealing. Rather, the material's extremely low yield point gives the impression of a low elastic modulus during tensile testing.

  18. A rainbow inverse problem

    Directory of Open Access Journals (Sweden)

    Calvez V.

    2010-12-01

    Full Text Available We consider the radiative transfer equation (RTE with reflection in a three-dimensional domain, infinite in two dimensions, and prove an existence result. Then, we study the inverse problem of retrieving the optical parameters from boundary measurements, with help of existing results by Choulli and Stefanov. This theoretical analysis is the framework of an attempt to model the color of the skin. For this purpose, a code has been developed to solve the RTE and to study the sensitivity of the measurements made by biophysicists with respect to the physiological parameters responsible for the optical properties of this complex, multi-layered material. On étudie l’équation du transfert radiatif (ETR dans un domaine tridimensionnel infini dans deux directions, et on prouve un résultat d’existence. On s’intéresse ensuite à la reconstruction des paramètres optiques à partir de mesures faites au bord, en s’appuyant sur des résultats de Choulli et Stefanov. Cette analyse sert de cadre théorique à un travail de modélisation de la couleur de la peau. Dans cette perspective, un code à été développé pour résoudre l’ETR et étudier la sensibilité des mesures effectuées par les biophysiciens par rapport aux paramètres physiologiques tenus pour responsables des propriétés optiques de ce complexe matériau multicouche.

  19. Perceptual centres in speech - an acoustic analysis

    Science.gov (United States)

    Scott, Sophie Kerttu

    Perceptual centres, or P-centres, represent the perceptual moments of occurrence of acoustic signals - the 'beat' of a sound. P-centres underlie the perception and production of rhythm in perceptually regular speech sequences. P-centres have been modelled both in speech and non speech (music) domains. The three aims of this thesis were toatest out current P-centre models to determine which best accounted for the experimental data bto identify a candidate parameter to map P-centres onto (a local approach) as opposed to the previous global models which rely upon the whole signal to determine the P-centre the final aim was to develop a model of P-centre location which could be applied to speech and non speech signals. The first aim was investigated by a series of experiments in which a) speech from different speakers was investigated to determine whether different models could account for variation between speakers b) whether rendering the amplitude time plot of a speech signal affects the P-centre of the signal c) whether increasing the amplitude at the offset of a speech signal alters P-centres in the production and perception of speech. The second aim was carried out by a) manipulating the rise time of different speech signals to determine whether the P-centre was affected, and whether the type of speech sound ramped affected the P-centre shift b) manipulating the rise time and decay time of a synthetic vowel to determine whether the onset alteration was had more affect on P-centre than the offset manipulation c) and whether the duration of a vowel affected the P-centre, if other attributes (amplitude, spectral contents) were held constant. The third aim - modelling P-centres - was based on these results. The Frequency dependent Amplitude Increase Model of P-centre location (FAIM) was developed using a modelling protocol, the APU GammaTone Filterbank and the speech from different speakers. The P-centres of the stimuli corpus were highly predicted by attributes of

  20. The new AMS control centre

    CERN Multimedia

    Anaïs Schaeffer

    2011-01-01

    Construction work for the future AMS control room began in November 2010 and should be finished this June. The new building, which will have been completed in record time thanks to the professionalism of the project team, will soon be ready to receive the initial data from the AMS experiment.     Luigi Scibile and Michael Poehler, from the GS department, at the AMS control centre construction site.   The Alpha Magnetic Spectrometer (AMS) is due to wing its way towards the International Space Station (ISS) on board the shuttle Discovery in April. Mainly intended for research on antimatter and dark matter, the data collected by AMS will be sent to Houston in the United States and then directly to CERN’s new Building 946. Construction work for the AMS control centre building on the Route Gentner at CERN’s Prévessin site started in November 2010 and must be completed in time to receive the first data from the spectrometer in June. “It normall...

  1. Crystallographic preferred orientation and deformation of deep Earth minerals

    Science.gov (United States)

    Kaercher, Pamela Michelle

    This thesis aims to provide further insight into crystallographic preferred orientation (CPO) and deformation mechanisms active at high pressure. Preferred orientation of iron-rich magnesiowustite (Mg,Fe)O, a major mantle mineral phase, stishovite (SiO2), the high pressure polymorph of quartz that is likely present in the lower crust and mantle, and in NaMgF3 + NaCl, an analog system to lower mantle minerals MgSiO3 + MgO, have been examined with synchrotron X-ray diffraction while at high pressure in either a diamond anvil cell or a multianvil press. Magnesiowustite, (Mg0.08Fe0.88)O, and wustite, Fe0.94O, were compressed up to 37 GPa at ambient temperature in diamond anvil cells (DAC) at the Advanced Light Source (ALS). X-ray diffraction patterns were taken in situ in radial geometry in order to study the evolution of CPO through the cubic-to-rhombohedral phase transition. Under uniaxial stress in the DAC, cubic texture developed (i.e. {100} c planes aligned perpendicular to the compression direction). Variant selection of preferred orientation was observed immediately following the transition to the rhombohedral phase. Upon decompression in the DAC, FeO reverted back to cubic symmetry and the cubic texture reappeared, demonstrating that the transition is reversible and has texture memory. The crystal structure of the high pressure SiO2 polymorph stishovite has been studied in detail, but little is known about texture development during deformation, which provides information for understanding subduction of quartz-bearing crustal rocks into the mantle. Radial DAC experiments were done at the ALS and the Advanced Photon Source (APS) while collecting X-ray diffraction patterns in radial geometry to examine in situ development of CPO. Starting pressure in the sample chamber was still in the quartz stability field, and compression of quartz produced a weak texture, likely due to Dauphine twinning. Following compression of quartz into the stishovite stability field

  2. Multidimensional NMR Inversion without Kronecker Products: Multilinear Inversion

    CERN Document Server

    Medellín, David; Torres-Verdín, Carlos

    2016-01-01

    Multidimensional NMR inversion using Kronecker products poses several challenges. First, kernel compression is only possible when the kernel matrices are separable, and in recent years, there has been an increasing interest in NMR sequences with non-separable kernels. Second, in three or more dimensions, the singular value decomposition is not unique; therefore kernel compression is not well-defined for higher dimensions. Without kernel compression, the Kronecker product yields matrices that require large amounts of memory, making the inversion intractable for personal computers. Finally, incorporating arbitrary regularization terms is not possible using the Lawson-Hanson (LH) or the Butler-Reeds-Dawson (BRD) algorithms. We develop a minimization-based inversion method that circumvents the above problems by using multilinear forms to perform multidimensional NMR inversion without using kernel compression or Kronecker products. The new method is memory efficient, requiring less than 0.1% of the memory required...

  3. Givental graphs and inversion symmetry

    CERN Document Server

    Dunin-Barkowski, P; Spitz, L

    2012-01-01

    Inversion symmetry is a very non-trivial discrete symmetry of Frobenius manifolds. It was obtained by Dubrovin from one of the elementary Schlesinger transformations of a special ODE associated to Frobenius manifold. In this paper, we review the Givental group action on Frobenius manifolds in terms of Feynman graphs and then we obtain an interpretation of the inversion symmetry in terms of the action of the Givental group. We also consider the implication of this interpretation of the inversion symmetry for the Schlesinger transformations and for the Hamiltonians of the associated principle hierarchy.

  4. Inverse Doppler Effects in Flute

    CERN Document Server

    Zhao, Xiao P; Liu, Song; Shen, Fang L; Li, Lin L; Luo, Chun R

    2015-01-01

    Here we report the observation of the inverse Doppler effects in a flute. It is experimentally verified that, when there is a relative movement between the source and the observer, the inverse Doppler effect could be detected for all seven pitches of a musical scale produced by a flute. Higher tone is associated with a greater shift in frequency. The effect of the inverse frequency shift may provide new insights into why the flute, with its euphonious tone, has been popular for thousands of years in Asia and Europe.

  5. Powering the Future Data Centre

    DEFF Research Database (Denmark)

    Zhang, Zhe

    2010-01-01

    The extended run Uninterruptible Power Supply system (UPSs) which powered by fuel cells and supercapcitors, is a promising solution for future data centre to obtain environmentfriendly energy efficient and cost effective. There are many challenges in power electronic interface circuits, because...... of the characteristics of these two power sources: long warm-up stage and low dynamics for fuel cell, and variable terminal voltage for supercapacitors. The motivation for this project was to find ways which can overcome those limitations to integrate fuel cells and supercapcitors to the system with high efficiency...... and high reliability. Therefore, special focus is given to hybrid dc conversion circuits. From an overview of current state-of-the-art, based on the work of others, the thesis will show the methods utilized in this project to combining fuel cells and supercapcitors for the frontend dc system with cascaded...

  6. Crystallographic Analysis of Nucleation at Hardness Indentations in High-Purity Aluminum

    DEFF Research Database (Denmark)

    Xu, Chaoling; Zhang, Yubin; Lin, Fengxiang

    2016-01-01

    Nucleation at Vickers hardness indentations has been studied in high-purity aluminum cold-rolled 12 pct. Electron channeling contrast was used to measure the size of the indentations and to detect nuclei, while electron backscattering diffraction was used to determine crystallographic orientations...

  7. Interpretation of quantitative crystallographic texture in copper electrodeposits on amorphous substrates

    DEFF Research Database (Denmark)

    Pantleon, Karen; Jensen, Jens Arne Dahl; Somers, Marcel A. J.

    2004-01-01

    Crystallographic texture and morphology in Cu electrodeposits was studied in relation to the current density and the content of the organic levelling additive 3-mercapto-1-propanesulfonate. The substrate onto which Cu was electrodeposited consisted of amorphous Ni-P in order to allow substrate...

  8. Crystallographic structural organization of human rhinovirus serotype 16, 14, 3, 2 and 1A

    Science.gov (United States)

    Janner, A.

    2006-07-01

    The capsid of the icosahedral virion is encapsulated between two polyhedra scaled according to the golden mean, each being composed of an icosahedron and a dodecahedron. Structural units of the coat proteins are enclosed into forms whose projections along the icosahedral symmetry axes obey the crystallographic law of rational indices.

  9. Parameter estimation and inverse problems

    CERN Document Server

    Aster, Richard C; Thurber, Clifford H

    2005-01-01

    Parameter Estimation and Inverse Problems primarily serves as a textbook for advanced undergraduate and introductory graduate courses. Class notes have been developed and reside on the World Wide Web for faciliting use and feedback by teaching colleagues. The authors'' treatment promotes an understanding of fundamental and practical issus associated with parameter fitting and inverse problems including basic theory of inverse problems, statistical issues, computational issues, and an understanding of how to analyze the success and limitations of solutions to these probles. The text is also a practical resource for general students and professional researchers, where techniques and concepts can be readily picked up on a chapter-by-chapter basis.Parameter Estimation and Inverse Problems is structured around a course at New Mexico Tech and is designed to be accessible to typical graduate students in the physical sciences who may not have an extensive mathematical background. It is accompanied by a Web site that...

  10. Testing earthquake source inversion methodologies

    KAUST Repository

    Page, Morgan T.

    2011-01-01

    Source Inversion Validation Workshop; Palm Springs, California, 11-12 September 2010; Nowadays earthquake source inversions are routinely performed after large earthquakes and represent a key connection between recorded seismic and geodetic data and the complex rupture process at depth. The resulting earthquake source models quantify the spatiotemporal evolution of ruptures. They are also used to provide a rapid assessment of the severity of an earthquake and to estimate losses. However, because of uncertainties in the data, assumed fault geometry and velocity structure, and chosen rupture parameterization, it is not clear which features of these source models are robust. Improved understanding of the uncertainty and reliability of earthquake source inversions will allow the scientific community to use the robust features of kinematic inversions to more thoroughly investigate the complexity of the rupture process and to better constrain other earthquakerelated computations, such as ground motion simulations and static stress change calculations.

  11. Statistical perspectives on inverse problems

    DEFF Research Database (Denmark)

    Andersen, Kim Emil

    of the interior of an object from electrical boundary measurements. One part of this thesis concerns statistical approaches for solving, possibly non-linear, inverse problems. Thus inverse problems are recasted in a form suitable for statistical inference. In particular, a Bayesian approach for regularisation...... is obtained by assuming that the a priori beliefs about the solution before having observed any data can be described by a prior distribution. The solution to the statistical inverse problem is then given by the posterior distribution obtained by Bayes' formula. Hence the solution of an ill-posed inverse...... problem is given in terms of probability distributions. Posterior inference is obtained by Markov chain Monte Carlo methods and new, powerful simulation techniques based on e.g. coupled Markov chains and simulated tempering is developed to improve the computational efficiency of the overall simulation...

  12. Bayesian Approach to Inverse Problems

    CERN Document Server

    2008-01-01

    Many scientific, medical or engineering problems raise the issue of recovering some physical quantities from indirect measurements; for instance, detecting or quantifying flaws or cracks within a material from acoustic or electromagnetic measurements at its surface is an essential problem of non-destructive evaluation. The concept of inverse problems precisely originates from the idea of inverting the laws of physics to recover a quantity of interest from measurable data.Unfortunately, most inverse problems are ill-posed, which means that precise and stable solutions are not easy to devise. Regularization is the key concept to solve inverse problems.The goal of this book is to deal with inverse problems and regularized solutions using the Bayesian statistical tools, with a particular view to signal and image estimation

  13. Shape Coexistence in 78 Ni and the new Island of Inversion centred in 74 Cr

    CERN Document Server

    Nowacki, F; Caurier, E; Bounthong, B

    2016-01-01

    Large Scale Shell Model calculations (SM-CI) predict that the region of deformation which comprises the heaviest Chromium and Iron isotopes at and beyond N=40 will merge with a new one at N=50 in an astonishing parallel to the N=20 and N=28 case in the Neon and Magnesium isotopes. We propose a valence space including the full pf-shell for the protons and the full sdg shell for the neutrons; which represents a comeback of the the harmonic oscillator shells in the very neutron rich regime. The onset of deformation is understood in the framework of the algebraic SU3-like structures linked to quadrupole dominance. Our calculations preserve the doubly magic nature of the ground state of 78 Ni, which, however, exhibits a well deformed prolate band at low excitation energy, providing a striking example of shape coexistence far from stability.

  14. Inversion Therapy: Can It Relieve Back Pain?

    Science.gov (United States)

    ... and Conditions Back pain Does inversion therapy relieve back pain? Is it safe? Answers from Edward R. Laskowski, M.D. Inversion therapy doesn't provide lasting relief from back pain, and it's not safe for everyone. Inversion therapy ...

  15. Inversion-symmetric topological insulators

    Science.gov (United States)

    Hughes, Taylor L.; Prodan, Emil; Bernevig, B. Andrei

    2011-06-01

    We analyze translationally invariant insulators with inversion symmetry that fall outside the current established classification of topological insulators. These insulators exhibit no edge or surface modes in the energy spectrum and hence they are not edge metals when the Fermi level is in the bulk gap. However, they do exhibit protected modes in the entanglement spectrum localized on the cut between two entangled regions. Their entanglement entropy cannot be made to vanish adiabatically, and hence the insulators can be called topological. There is a direct connection between the inversion eigenvalues of the Hamiltonian band structure and the midgap states in the entanglement spectrum. The classification of protected entanglement levels is given by an integer N, which is the difference between the negative inversion eigenvalues at inversion symmetric points in the Brillouin zone, taken in sets of 2. When the Hamiltonian describes a Chern insulator or a nontrivial time-reversal invariant topological insulator, the entirety of the entanglement spectrum exhibits spectral flow. If the Chern number is zero for the former, or time reversal is broken in the latter, the entanglement spectrum does not have spectral flow, but, depending on the inversion eigenvalues, can still exhibit protected midgap bands similar to impurity bands in normal semiconductors. Although spectral flow is broken (implying the absence of real edge or surface modes in the original Hamiltonian), the midgap entanglement bands cannot be adiabatically removed, and the insulator is “topological.” We analyze the linear response of these insulators and provide proofs and examples of when the inversion eigenvalues determine a nontrivial charge polarization, a quantum Hall effect, an anisotropic three-dimensional (3D) quantum Hall effect, or a magnetoelectric polarization. In one dimension, we establish a link between the product of the inversion eigenvalues of all occupied bands at all inversion

  16. -Colour Self-Inverse Compositions

    Indian Academy of Sciences (India)

    Geetika Narang; A K Agarwal

    2006-08-01

    MacMahon’s definition of self-inverse composition is extended to -colour self-inverse composition. This introduces four new sequences which satisfy the same recurrence relation with different initial conditions like the famous Fibonacci and Lucas sequences. For these new sequences explicit formulas, recurrence relations, generating functions and a summation formula are obtained. Two new binomial identities with combinatorial meaning are also given.

  17. Thermal measurements and inverse techniques

    CERN Document Server

    Orlande, Helcio RB; Maillet, Denis; Cotta, Renato M

    2011-01-01

    With its uncommon presentation of instructional material regarding mathematical modeling, measurements, and solution of inverse problems, Thermal Measurements and Inverse Techniques is a one-stop reference for those dealing with various aspects of heat transfer. Progress in mathematical modeling of complex industrial and environmental systems has enabled numerical simulations of most physical phenomena. In addition, recent advances in thermal instrumentation and heat transfer modeling have improved experimental procedures and indirect measurements for heat transfer research of both natural phe

  18. Activities of Radiation Protection Centre in 2000

    CERN Document Server

    Radiat. Prot. Cent. Vilnius

    2001-01-01

    Description of the activities of Radiation Protection Centre in 2000 is presented. Radiation Protection Centre is responsible for radiation protection issues. Currently there are six departments at Radiation Protection Centre: two in Vilnius - Department of Radiation Protection Supervision and Control and Department of Programs and Expertise, and four in the districts. Brief information on subject controlled by each departments is provided focusing on main achievements and events.

  19. Criteria of Categorizing Logistics and Distribution Centres

    OpenAIRE

    Darko Babić; Anđelko Šćukanec; Kristijan Rogic

    2011-01-01

    Logistics and distribution centres represent very significant infrastructure elements of the macro-logistic system. The creation of the logistics and distribution centres and their connection into a wide (global) network have resulted in the creation of conditions for an adequate distribution of labour and significant increase in the productivity of all the logistics elements and processes, noting that the logistics and distribution centres in this concept have a superregional significance. ...

  20. Smart work centres in rural areas

    DEFF Research Database (Denmark)

    Lorentzen, Anne Birte

    This paper discusses the establishment of telework centres as an element in local development strategies in rural areas, with a particular view to two new telework centres in region North Denmark. The paper argues that telework centres do not represent an easy solution to problems of local develo...... development and environmental sustainability, and further, that technology may not even be the most important feature needed to make them function as such....

  1. Chromatid Painting for Chromosomal Inversion Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a novel approach to the detection of chromosomal inversions. Transmissible chromosome aberrations (translocations and inversions) have profound genetic...

  2. Criteria of Categorizing Logistics and Distribution Centres

    Directory of Open Access Journals (Sweden)

    Darko Babić

    2011-07-01

    Full Text Available Logistics and distribution centres represent very significant infrastructure elements of the macro-logistic system. The creation of the logistics and distribution centres and their connection into a wide (global network have resulted in the creation of conditions for an adequate distribution of labour and significant increase in the productivity of all the logistics elements and processes, noting that the logistics and distribution centres in this concept have a superregional significance. This paper represents the summary (results of the research that was carried out on a large number of logistics and distribution centres with the aim of considering the complexity and the issues related to the logistics and distribution centres and the distribution network, their elements and action of the subsystems according to the following criteria: spatial, technical, technological, and organizational, with the aim of defining the categorisation model of the logistics and distribution centres. The analysis of the selected data collected during the research has resulted in defining of the categorisation model of the logistics and distribution centres which foresees six categories. Each of the foreseen categories has been defined according to the set model by the mentioned traffic, technical and technological, and organisational characteristics and the level of service. This is precisely where the application of the categorisation model of the logistics and distribution centres can be found, which will define the relevant categories of the centres applicable in the creation of effective distribution

  3. Multidimensional NMR inversion without Kronecker products: Multilinear inversion

    Science.gov (United States)

    Medellín, David; Ravi, Vivek R.; Torres-Verdín, Carlos

    2016-08-01

    Multidimensional NMR inversion using Kronecker products poses several challenges. First, kernel compression is only possible when the kernel matrices are separable, and in recent years, there has been an increasing interest in NMR sequences with non-separable kernels. Second, in three or more dimensions, the singular value decomposition is not unique; therefore kernel compression is not well-defined for higher dimensions. Without kernel compression, the Kronecker product yields matrices that require large amounts of memory, making the inversion intractable for personal computers. Finally, incorporating arbitrary regularization terms is not possible using the Lawson-Hanson (LH) or the Butler-Reeds-Dawson (BRD) algorithms. We develop a minimization-based inversion method that circumvents the above problems by using multilinear forms to perform multidimensional NMR inversion without using kernel compression or Kronecker products. The new method is memory efficient, requiring less than 0.1% of the memory required by the LH or BRD methods. It can also be extended to arbitrary dimensions and adapted to include non-separable kernels, linear constraints, and arbitrary regularization terms. Additionally, it is easy to implement because only a cost function and its first derivative are required to perform the inversion.

  4. Human Centred Design: a bibliometric overview based on Science Direct

    Directory of Open Access Journals (Sweden)

    Lucas José Garcia

    2016-05-01

    Full Text Available This article aims to realize a bibliometric review on Science Direct to create a outlook about Human Centred Design in order to identify the most significant authors, journals and key-words as well as the most recurrent denomination about the subject. The method employed consist of application of three classical bibliometric laws: the Inverse Square Law of Lotka; the Bradford’s Law of Scattering and; The frequency law of words in a text of Zipf. The results indicate that the subject is not a main subject of Design and related areas and does not have a main author based on Science Direct. The journals covered with more articles about the subject are the International Journal of Industrial Ergonomics and the Applied Ergonomics.

  5. Capturing Reality at Centre Block

    Science.gov (United States)

    Boulanger, C.; Ouimet, C.; Yeomans, N.

    2017-08-01

    The Centre Block of Canada's Parliament buildings, National Historic Site of Canada is set to undergo a major rehabilitation project that will take approximately 10 years to complete. In preparation for this work, Heritage Conservation Services (HCS) of Public Services and Procurement Canada has been completing heritage documentation of the entire site which includes laser scanning of all interior rooms and accessible confined spaces such as attics and other similar areas. Other documentation completed includes detailed photogrammetric documentation of rooms and areas of high heritage value. Some of these high heritage value spaces present certain challenges such as accessibility due to the height and the size of the spaces. Another challenge is the poor lighting conditions, requiring the use of flash or strobe lighting to either compliment or completely eliminate the available ambient lighting. All the spaces captured at this higher level of detail were also captured with laser scanning. This allowed the team to validate the information and conduct a quality review of the photogrammetric data. As a result of this exercise, the team realized that in most, if not all cases, the photogrammetric data was more detailed and at a higher quality then the terrestrial laser scanning data. The purpose and motivation of this paper is to present these findings, as well provide the advantages and disadvantages of the two methods and data sets.

  6. CAPTURING REALITY AT CENTRE BLOCK

    Directory of Open Access Journals (Sweden)

    C. Boulanger

    2017-08-01

    Full Text Available The Centre Block of Canada’s Parliament buildings, National Historic Site of Canada is set to undergo a major rehabilitation project that will take approximately 10 years to complete. In preparation for this work, Heritage Conservation Services (HCS of Public Services and Procurement Canada has been completing heritage documentation of the entire site which includes laser scanning of all interior rooms and accessible confined spaces such as attics and other similar areas. Other documentation completed includes detailed photogrammetric documentation of rooms and areas of high heritage value. Some of these high heritage value spaces present certain challenges such as accessibility due to the height and the size of the spaces. Another challenge is the poor lighting conditions, requiring the use of flash or strobe lighting to either compliment or completely eliminate the available ambient lighting. All the spaces captured at this higher level of detail were also captured with laser scanning. This allowed the team to validate the information and conduct a quality review of the photogrammetric data. As a result of this exercise, the team realized that in most, if not all cases, the photogrammetric data was more detailed and at a higher quality then the terrestrial laser scanning data. The purpose and motivation of this paper is to present these findings, as well provide the advantages and disadvantages of the two methods and data sets.

  7. Laparoscopic adrenalectomy: Single centre experience.

    LENUS (Irish Health Repository)

    O'Farrell, N J

    2012-02-01

    BACKGROUND: Laparoscopic adrenalectomy is an attractive alternative to the traditional open approach in the surgical excision of an adrenal gland. It has replaced open adrenalectomy in our institution and we review our experience to date. METHODS: All cases of laparoscopic adrenalectomies in our hospital over eight years (from 2001 to May 2009) were retrospectively reviewed. Patient demographics, diagnosis, length of hospital stay, histology and all operative and post-operative details were evaluated. RESULTS: Fifty-five laparoscopic adrenalectomies (LA) were performed on 51 patients over eight years. The mean age was 48 years (Range 16-86 years) with the male: female ratio 1:2. Twenty-three cases had a right adrenalectomy, 24 had a left adrenalectomy and the remaining four patients had bilateral adrenalectomies. 91% were successfully completed laparoscopically with five converted to an open approach. Adenomas (functional and non functional) were the leading indication for LA, followed by phaeochromocytomas. Other indications for LA included Cushing\\'s disease, adrenal malignancies and rarer pathologies. There was one mortality from necrotising pancreatitis following a left adrenalectomy for severe Cushing\\'s disease, with subsequent death 10 days later. CONCLUSION: Laparoscopic adrenalectomy is effective for the treatment of adrenal tumours, fulfilling the criteria for the ideal minimally invasive procedure. It has replaced the traditional open approach in our centre and is a safe and effective alternative. However, in the case of severe Cushing\\'s disease, laparoscopic adrenalectomy has the potential for significant adverse outcomes and mortality.

  8. VLF Science at Indian Centre for Space Physics

    Science.gov (United States)

    Chakrabarti, Sandip Kumar

    2016-07-01

    Indian Centre for Space Physics has been monitoring VLF signals from stations around the world at its laboratories at Kolkata and Sitapur (Ionospheric and Earthquake Research Centre) as well as at several places throughout India when in a campaign mode. We have been interested to study high energy events from space, such as solar flares and gamma ray bursts. We have made studies during multiple solar eclipses and most importantly made substantial progress in the problem of lithosphere-ionosphere coupling while understanding various types of anomalies prior to major earthquakes. Other effects such as AGWs and LEPs are being studied. We have experience of two antarctic expedition and obtained VLF data from both Maitri and Bharati stations of India, which revealed, among other things, how the signal attenuation can indicate the extent of ice mass in Antarctica. We have been able to reproduce various VLF perturbation events using Atmospheric Chemical evolution model coupled with LWPC code. For instance we have reproduced solar flare induced VLF amplitude perturbation pattern by completely ab initio calculation. We also targeted the inverse problem, namely, deduction of the injected radiation spectra from space from the VLF signal alone, thereby establishing that the Earth can be used as a gigantic detector. These interesting results would be presented in my review talk.

  9. Oil Trading Centre to Reopen in Shanghai

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ Chinese oil companies will likely resume activities at the oil trading centre in Shanghai this year, a move to further liberalize the once tightly controlled oil market. The centre will trade forward contracts for refined oil products,including gasoline, diesel oil, kerosene and fuel oil, industrial sources said.

  10. Student-Centred Learning (SCL): Roles Changed?

    Science.gov (United States)

    Onurkan Aliusta, Gülen; Özer, Bekir

    2017-01-01

    This paper addresses the espoused and enacted practices of high school teachers with regard to student-centred learning (SCL). Explanatory mixed-method design, where quantitative strand is followed by qualitative one, is employed. While the quantitative strand aims to explore teachers' perceptions regarding the extent student-centred teacher and…

  11. Neighbourhood Centres – Organisation, Management and Finance

    DEFF Research Database (Denmark)

    Larsen, Jacob Norvig

    From the late 1990s neighbourhood centres were brought to the fore of public urban regen-eration policy, because they were seen as a means to accelerate the formation of social capital in deprived urban neighbourhoods. A number of such local community centres were established with substantial pub...

  12. Student Centred Approaches: Teachers' Learning and Practice

    Science.gov (United States)

    Vale, Colleen; Davies, Anne; Weaven, Mary; Hooley, Neil

    2010-01-01

    Student centred approaches to teaching and learning in mathematics is one of the reforms currently being advocated and implemented to improve mathematics outcomes for students from low socio-economic status (SES) backgrounds. The models, meanings and practices of student centred approaches explored in this paper reveal that a constructivist model…

  13. The Press Research Centre, 1956-1976.

    Science.gov (United States)

    Press Research Centre, Krakow (Poland).

    In 1956, the Press Research Centre was established in Cracow, Poland by a group of journalists and publishers, for the purpose of instituting press research that would have practical applications. The aims of the Centre were to conduct studies on the history of the Polish press, the contemporary press, press readership, and editorial techniques.…

  14. The role of the sexual assault centre.

    LENUS (Irish Health Repository)

    Eogan, Maeve

    2013-02-01

    Sexual Assault Centres provide multidisciplinary care for men and women who have experienced sexual crime. These centres enable provision of medical, forensic, psychological support and follow-up care, even if patients chose not to report the incident to the police service. Sexual Support Centres need to provide a ring-fenced, forensically clean environment. They need to be appropriately staffed and available 24 hours a day, 7 days a week to allow prompt provision of medical and supportive care and collection of forensic evidence. Sexual Assault Centres work best within the context of a core agreed model of care, which includes defined multi-agency guidelines and care pathways, close links with forensic science and police services, and designated and sustainable funding arrangements. Additionally, Sexual Assault Centres also participate in patient, staff and community education and risk reduction. Furthermore, they contribute to the development, evaluation and implementation of national strategies on domestic, sexual and gender-based violence.

  15. Centre for urban ecotechnology in ``Oeksnehallen``

    Energy Technology Data Exchange (ETDEWEB)

    1992-03-01

    The Lord Mayor`s Department of the municipality of Copenhagen, Denmark, has with support from this project made a proposal for the establishment of the Centre for Urban Ecotechnology in ``Oeksnehallen``, located in the Vesterbro area of the city. The centre should contribute to the dissemination of knowledge on ecological techniques (regarding passive solar energy etc.) to the inhabitants of Vesterbro and other citizens of Copenhagen, and also serve as a centre in an European context. The ecological demonstration centre will cover an area of two thousand square meters and will also include a cafe, a room for showing coloured slides, facilities for exhibitions created by the center and interested firms etc. The centre should play an important role as part of the ecological concept of urban renewal in Vesterbro. (author).

  16. Subadditive functions and their (pseudo-)inverses

    DEFF Research Database (Denmark)

    Østerdal, Lars Peter

    2006-01-01

    The paper considers non-negative increasing functions on intervals with left endpoint closed at zero and investigates the duality between subadditivity and superadditivity via the inverse function and pseudo-inverses......The paper considers non-negative increasing functions on intervals with left endpoint closed at zero and investigates the duality between subadditivity and superadditivity via the inverse function and pseudo-inverses...

  17. The representation and computation of generalized inverse

    Science.gov (United States)

    Sheng, Xingping; Chen, Guoliang; Gong, Yi

    2008-03-01

    This paper presents a novel representation for the generalized inverse . Based on this, we give an algorithm to compute this generalized inverse. As an application, we use Gauss-Jordan elimination to compute the weighted Moore-Penrose inverse and the Drazin inverse Ad.

  18. Exploring the Hamiltonian inversion landscape.

    Science.gov (United States)

    Donovan, Ashley; Rabitz, Herschel

    2014-08-07

    The identification of quantum system Hamiltonians through the use of experimental data remains an important research goal. Seeking a Hamiltonian that is consistent with experimental measurements constitutes an excursion over a Hamiltonian inversion landscape, which is the quality of reproducing the data as a function of the Hamiltonian parameters. Recent theoretical work showed that with sufficient experimental data there should be local convexity about the true Hamiltonian on the landscape. The present paper builds on this result and performs simulations to test whether such convexity is observed. A gradient-based Hamiltonian search algorithm is incorporated into an inversion routine as a means to explore the local inversion landscape. The simulations consider idealized noise-free as well as noise-ridden experimental data. The results suggest that a sizable convex domain exists about the true Hamiltonian, even with a modest amount of experimental data and in the presence of a reasonable level of noise.

  19. Optimization and geophysical inverse problems

    Energy Technology Data Exchange (ETDEWEB)

    Barhen, J.; Berryman, J.G.; Borcea, L.; Dennis, J.; de Groot-Hedlin, C.; Gilbert, F.; Gill, P.; Heinkenschloss, M.; Johnson, L.; McEvilly, T.; More, J.; Newman, G.; Oldenburg, D.; Parker, P.; Porto, B.; Sen, M.; Torczon, V.; Vasco, D.; Woodward, N.B.

    2000-10-01

    A fundamental part of geophysics is to make inferences about the interior of the earth on the basis of data collected at or near the surface of the earth. In almost all cases these measured data are only indirectly related to the properties of the earth that are of interest, so an inverse problem must be solved in order to obtain estimates of the physical properties within the earth. In February of 1999 the U.S. Department of Energy sponsored a workshop that was intended to examine the methods currently being used to solve geophysical inverse problems and to consider what new approaches should be explored in the future. The interdisciplinary area between inverse problems in geophysics and optimization methods in mathematics was specifically targeted as one where an interchange of ideas was likely to be fruitful. Thus about half of the participants were actively involved in solving geophysical inverse problems and about half were actively involved in research on general optimization methods. This report presents some of the topics that were explored at the workshop and the conclusions that were reached. In general, the objective of a geophysical inverse problem is to find an earth model, described by a set of physical parameters, that is consistent with the observational data. It is usually assumed that the forward problem, that of calculating simulated data for an earth model, is well enough understood so that reasonably accurate synthetic data can be generated for an arbitrary model. The inverse problem is then posed as an optimization problem, where the function to be optimized is variously called the objective function, misfit function, or fitness function. The objective function is typically some measure of the difference between observational data and synthetic data calculated for a trial model. However, because of incomplete and inaccurate data, the objective function often incorporates some additional form of regularization, such as a measure of smoothness

  20. Inverse methods for radiation transport

    Science.gov (United States)

    Bledsoe, Keith C.

    Implicit optimization methods for solving the inverse transport problems of interface location identification, source isotope weight fraction identification, shield material identification, and material mass density identification are explored. Among these optimization methods are the Schwinger inverse method, Levenberg-Marquardt method, and evolutionary algorithms. Inverse problems are studied in one-dimensional spherical and two-dimensional cylindrical geometries. The scalar fluxes of unscattered gamma-ray lines, leakages of neutron-induced gamma-ray lines, and/or neutron multiplication in the system are assumed to be measured. Each optimization method is studied on numerical test problems in which the measured data is simulated using the same deterministic transport code used in the optimization process (assuming perfectly consistent measurements) and using a Monte Carlo code (assuming less-consistent, more realistic measurements). The Schwinger inverse method and Levenberg-Marquardt methods are found to be successful for problems with relatively few (i.e. 4 or fewer) unknown parameters, with the former being the best for unknown isotope problems and the latter being more adept at interface location, unknown material mass density, and mixed parameter problems. A study of a variety of evolutionary algorithms indicates that the differential evolution method is the best for inverse transport problems, and outperforms the Levenberg-Marquardt method on problems with large numbers of unknowns. An algorithm created by combining different variants of the differential evolution method is shown to be highly successful on spherical problems with unscattered gamma-ray lines, while a basic differential evolution approach is more useful for problems with scattering and in cylindrical geometries. A hybrid differential evolution/Levenberg-Marquardt algorithm also was found to show promise for fast and robust solution of inverse problems.

  1. -Dimensional Fractional Lagrange's Inversion Theorem

    Directory of Open Access Journals (Sweden)

    F. A. Abd El-Salam

    2013-01-01

    Full Text Available Using Riemann-Liouville fractional differential operator, a fractional extension of the Lagrange inversion theorem and related formulas are developed. The required basic definitions, lemmas, and theorems in the fractional calculus are presented. A fractional form of Lagrange's expansion for one implicitly defined independent variable is obtained. Then, a fractional version of Lagrange's expansion in more than one unknown function is generalized. For extending the treatment in higher dimensions, some relevant vectors and tensors definitions and notations are presented. A fractional Taylor expansion of a function of -dimensional polyadics is derived. A fractional -dimensional Lagrange inversion theorem is proved.

  2. Thermoelectric properties of inverse opals

    Science.gov (United States)

    Mahan, G. D.; Poilvert, N.; Crespi, V. H.

    2016-02-01

    Rayleigh's method [Philos. Mag. Ser. 5 34, 481 (1892)] is used to solve for the classical thermoelectric equations in inverse opals. His theory predicts that in an inverse opal, with periodic holes, the Seebeck coefficient and the figure of merit are identical to that of the bulk material. We also provide a major revision to Rayleigh's method, in using the electrochemical potential as an important variable, instead of the electrostatic potential. We also show that in some cases, the thermal boundary resistance is important in the effective thermal conductivity.

  3. Population inversion by chirped pulses

    Energy Technology Data Exchange (ETDEWEB)

    Lu Tianshi [Department of Mathematics and Statistics, Wichita State University, Wichita, Kansas 67260-0033 (United States)

    2011-09-15

    In this paper, we analyze the condition for complete population inversion by a chirped pulse over a finite duration. The nonadiabatic transition probability is mapped in the two-dimensional parameter space of coupling strength and detuning amplitude. Asymptotic forms of the probability are derived by the interference of nonadiabatic transitions for sinusoidal and triangular pulses. The qualitative difference between the maps for the two types of pulses is accounted for. The map is used for the design of stable inversion pulses under specific accuracy thresholds.

  4. Size Estimates in Inverse Problems

    KAUST Repository

    Di Cristo, Michele

    2014-01-06

    Detection of inclusions or obstacles inside a body by boundary measurements is an inverse problems very useful in practical applications. When only finite numbers of measurements are available, we try to detect some information on the embedded object such as its size. In this talk we review some recent results on several inverse problems. The idea is to provide constructive upper and lower estimates of the area/volume of the unknown defect in terms of a quantity related to the work that can be expressed with the available boundary data.

  5. Inverse methods in hydrologic optics

    Directory of Open Access Journals (Sweden)

    Howard R. Gordon

    2002-03-01

    Full Text Available Methods for solving the hydrologic-optics inverse problem, i.e., estimating the inherent optical properties of a water body based solely on measurements of the apparent optical properties, are reviewed in detail. A new method is developed for the inverse problem in water bodies in which fluorescence is important. It is shown that in principle, given profiles of the spectra of up- and downwelling irradiance, estimation of the coefficient of inelastic scattering from any wave band to any other wave band can be effected.

  6. Darwin's "strange inversion of reasoning".

    Science.gov (United States)

    Dennett, Daniel

    2009-06-16

    Darwin's theory of evolution by natural selection unifies the world of physics with the world of meaning and purpose by proposing a deeply counterintuitive "inversion of reasoning" (according to a 19th century critic): "to make a perfect and beautiful machine, it is not requisite to know how to make it" [MacKenzie RB (1868) (Nisbet & Co., London)]. Turing proposed a similar inversion: to be a perfect and beautiful computing machine, it is not requisite to know what arithmetic is. Together, these ideas help to explain how we human intelligences came to be able to discern the reasons for all of the adaptations of life, including our own.

  7. Big Surveys, Big Data Centres

    Science.gov (United States)

    Schade, D.

    2016-06-01

    Well-designed astronomical surveys are powerful and have consistently been keystones of scientific progress. The Byurakan Surveys using a Schmidt telescope with an objective prism produced a list of about 3000 UV-excess Markarian galaxies but these objects have stimulated an enormous amount of further study and appear in over 16,000 publications. The CFHT Legacy Surveys used a wide-field imager to cover thousands of square degrees and those surveys are mentioned in over 1100 publications since 2002. Both ground and space-based astronomy have been increasing their investments in survey work. Survey instrumentation strives toward fair samples and large sky coverage and therefore strives to produce massive datasets. Thus we are faced with the "big data" problem in astronomy. Survey datasets require specialized approaches to data management. Big data places additional challenging requirements for data management. If the term "big data" is defined as data collections that are too large to move then there are profound implications for the infrastructure that supports big data science. The current model of data centres is obsolete. In the era of big data the central problem is how to create architectures that effectively manage the relationship between data collections, networks, processing capabilities, and software, given the science requirements of the projects that need to be executed. A stand alone data silo cannot support big data science. I'll describe the current efforts of the Canadian community to deal with this situation and our successes and failures. I'll talk about how we are planning in the next decade to try to create a workable and adaptable solution to support big data science.

  8. Time of falling of a quantum particle into an inverse square potential

    OpenAIRE

    Vasyuta, Vasyl; Tkachuk, Volodymyr

    2015-01-01

    Evolution of a particle in an inverse square potential is studied. We derive an equation of motion for $\\left$ and solve it exactly. It gives us a possibility to identify the conditions under which a falling of a quantum particle into an attractive centre is possible. We get the time of falling of a particle from an initial state into the centre. An example of a quasi-stationary state which evolves with $\\left$ being constant in time is given. We demonstrate the existence of quantum limit of ...

  9. An analysis on the inversion of polynomials

    OpenAIRE

    M. F. González-Cardel; R. Díaz-Uribe

    2006-01-01

    In this work the application and the intervals of validity of an inverse polynomial, according to the method proposed by Arfken [1] for the inversion of series, is analyzed. It is shown that, for the inverse polynomial there exists a restricted domain whose longitude depends on the magnitude of the acceptable error when the inverse polynomial is used to approximate the inverse function of the original polynomial. A method for calculating the error of the approximation and its use in determini...

  10. The relation between microstructure and crystallographic orientation in rolled copper and brass

    DEFF Research Database (Denmark)

    Christoffersen, H.; Leffers, Torben

    2002-01-01

    The relation between microstructure and crystallographic orientation is investigated in rolled copper and brass. For the two main types of microstructure in copper (the high wall density and the low wall density structure) there is a certain relation: theorientations corresponding to a specific...... type tend to cluster in certain regions of orientation space. However, the clustering is not very pronounced (there is a lot of overlap), and it cannot be related to any model. There is also a certain grain-sizeeffect: the average grain with high wall density structure is larger than the average grain...... with low wall density structure. For a third type of microstructure (to be described) there is a very clear relation to the crystallographic orientation. For brassthe distinction is between grains with and grains without deformation twins. There is a clear trend for the grains with twins to cluster...

  11. The X-ray system of crystallographic programs for any computer having a PIDGIN FORTRAN compiler

    Science.gov (United States)

    Stewart, J. M.; Kruger, G. J.; Ammon, H. L.; Dickinson, C.; Hall, S. R.

    1972-01-01

    A manual is presented for the use of a library of crystallographic programs. This library, called the X-ray system, is designed to carry out the calculations required to solve the structure of crystals by diffraction techniques. It has been implemented at the University of Maryland on the Univac 1108. It has, however, been developed and run on a variety of machines under various operating systems. It is considered to be an essentially machine independent library of applications programs. The report includes definition of crystallographic computing terms, program descriptions, with some text to show their application to specific crystal problems, detailed card input descriptions, mass storage file structure and some example run streams.

  12. Crystallographic dependence of CO activation on cobalt catalysts: HCP versus FCC.

    Science.gov (United States)

    Liu, Jin-Xun; Su, Hai-Yan; Sun, Da-Peng; Zhang, Bing-Yan; Li, Wei-Xue

    2013-11-06

    Identifying the structure sensitivity of catalysts in reactions, such as Fischer-Tropsch synthesis from CO and H2 over cobalt catalysts, is an important yet challenging issue in heterogeneous catalysis. Based on a first-principles kinetic study, we find for the first time that CO activation on hexagonal close-packed (HCP) Co not only has much higher intrinsic activity than that of face centered-cubic (FCC) Co but also prefers a different reaction route, i.e., direct dissociation with HCP Co but H-assisted dissociation on the FCC Co. The origin is identified from the formation of various denser yet favorable active sites on HCP Co not available for FCC Co, due to their distinct crystallographic structure and morphology. The great dependence of the activity on the crystallographic structure and morphology of the catalysts revealed here may open a new avenue for better, stable catalysts with maximum mass-specific reactivity.

  13. Novel Kac-Moody-type affine extensions of non-crystallographic Coxeter groups

    CERN Document Server

    Dechant, Pierre-Philippe; Twarock, Reidun

    2011-01-01

    Motivated by recent results in mathematical virology, we present novel asymmetric Z[tau]-integer-valued affine extensions of the non-crystallographic Coxeter groups H_2, H_3 and H_4 derived in a Kac-Moody-type formalism. In particular, we show that the affine reflection planes which extend the Coxeter group H_3 generate (twist) translations along 2-, 3- and 5-fold axes of icosahedral symmetry and classify these translations in terms of Fibonacci recursion relations, thus providing a framework to explain results of Keef et al and Wardman at the group level. Finally, we extend this classification to the case of the non-crystallographic Coxeter groups H_2 and H_4. These results should have applications in physics (quasicrystals), biology (viruses) and chemistry (fullerenes).

  14. Determination of crystallographic and macroscopic orientation of planar structures in TEM

    DEFF Research Database (Denmark)

    Huang, X.; Liu, Q.

    1998-01-01

    With the aid of a double-tilt holder in a transmission electron microscope (TEM), simple methods are described for determination of the crystallographic orientation of a planar structure and for calculation of the macroscopic orientation of the planar structure. The correlation between a planar s...... taken at tilted positions, can be transformed to the real macroscopic orientation of the planar structures with estimated error of about +/- 2 degrees. (C) 1998 Elsevier Science B.V. All rights reserved....... structure and a crystallographic plane can be found by comparing the differences in their trace directions on the projection plane and inclination angles with respect to that plane. The angles between the traces of planar structures and the sample axis measured from the TEM micrographs, which have been...

  15. Acanthamoeba polyphaga mimivirus NDK: preliminary crystallographic analysis of the first viral nucleoside diphosphate kinase.

    Science.gov (United States)

    Jeudy, Sandra; Coutard, Bruno; Lebrun, Régine; Abergel, Chantal

    2005-06-01

    The complete sequence of the largest known double-stranded DNA virus, Acanthamoeba polyphaga mimivirus, has recently been determined [Raoult et al. (2004), Science, 306, 1344-1350] and revealed numerous genes not expected to be found in a virus. A comprehensive structural and functional study of these gene products was initiated [Abergel et al. (2005), Acta Cryst. F61, 212-215] both to better understand their role in the virus physiology and to obtain some clues to the origin of DNA viruses. Here, the preliminary crystallographic analysis of the viral nucleoside diphosphate kinase protein is reported. The crystal belongs to the cubic space group P2(1)3, with unit-cell parameter 99.425 A. The self-rotation function confirms that there are two monomers per asymmetric unit related by a twofold non-crystallographic axis and that the unit cell thus contains four biological entities.

  16. Preferred crystallographic orientation in the ice I ← II transformation and the flow of ice II

    Science.gov (United States)

    Bennett, K.; Wenk, H.-R.; Durham, W.B.; Stern, L.A.; Kirby, S.H.

    1997-01-01

    The preferred crystallographic orientation developed during the ice I ← II transformation and during the plastic flow of ice II was measured in polycrystalline deuterium oxide (D2O) specimens using low-temperature neutron diffraction. Samples partially transformed from ice I to II under a non-hydrostatic stress developed a preferred crystallographic orientation in the ice II. Samples of pure ice II transformed from ice I under a hydrostatic stress and then when compressed axially, developed a strong preferred orientation of compression axes parallel to (1010). A match to the observed preferred orientation using the viscoplastic self-consistent theory was obtained only when (1010) [0001] was taken as the predominant slip system in ice II.

  17. Mineralogical, crystallographic and morphological characteristics of natural kaolins from the Ivory Coast (West Africa)

    Science.gov (United States)

    Sei, J.; Morato, F.; Kra, G.; Staunton, S.; Quiquampoix, H.; Jumas, J. C.; Olivier-Fourcade, J.

    2006-10-01

    Thirteen clay samples from four deposits in the Ivory Coast (West Africa) were studied using X-ray diffraction, thermogravimetric analysis and chemical analysis. Mineralogical, crystallographic and morphological characteristics of these samples are given. Kaolinite is the principal mineral but other minerals are present in small quantities: illite, quartz, anatase and iron oxides (oxides and oxyhydroxides). The crystallographic, morphological and surface characteristics are influenced by the presence of these impurities. In particular, the presence of iron oxides was associated with reduced structural ordering and thermal stability of kaolinite and increased specific surface area. These clays could be used in the ceramics industry to make tiles and bricks, and also in agronomy as supports for chemical fertilizers or for environmental protection by immobilising potentially toxic waste products.

  18. Crystallographic Analysis of Nucleation at Hardness Indentations in High-Purity Aluminum

    Science.gov (United States)

    Xu, Chaoling; Zhang, Yubin; Lin, Fengxiang; Wu, Guilin; Liu, Qing; Juul Jensen, Dorte

    2016-12-01

    Nucleation at Vickers hardness indentations has been studied in high-purity aluminum cold-rolled 12 pct. Electron channeling contrast was used to measure the size of the indentations and to detect nuclei, while electron backscattering diffraction was used to determine crystallographic orientations. It is found that indentations are preferential nucleation sites. The crystallographic orientations of the deformed grains affect the hardness and the nucleation potentials at the indentations. Higher hardness gives increased nucleation probabilities. Orientation relationships between nuclei developed at different indentations within one original grain are analyzed and it is found that the orientation distribution of the nuclei is far from random. It is suggested that it relates to the orientations present near the indentation tips which in turn depend on the orientation of the selected grain in which they form. Finally, possible nucleation mechanisms are briefly discussed.

  19. Expression, purification and preliminary crystallographic characterization of FlhF from Bacillus subtilis

    Energy Technology Data Exchange (ETDEWEB)

    Bange, Gert; Petzold, Georg; Wild, Klemens; Sinning, Irmgard, E-mail: irmi.sinning@bzh.uni-heidelberg.de [Heidelberg University Biochemistry Centre (BZH), INF 328, 69120 Heidelberg (Germany)

    2007-05-01

    Preliminary crystallographic data are reported for the third SRP GTPase FlhF from Bacillus subtilis. The Gram-positive bacterium Bacillus subtilis contains three proteins belonging to the signal recognition particle (SRP) type GTPase family. The well characterized signal sequence-binding protein SRP54 and the SRP receptor protein FtsY are universally conserved components of the SRP system of protein transport. The third member, FlhF, has been implicated in the placement and assembly of polar flagella. This article describes the overexpression and preliminary X-ray crystallographic analysis of an FlhF fragment that corresponds to the well characterized GTPase domains in SRP54 and FtsY. Three crystal forms are reported with either GDP or GMPPNP and diffract to a resolution of about 3 Å.

  20. Crystallographic orientation and induced potential effects in photoelectron emission from metal surfaces by ultrashort laser pulses

    CERN Document Server

    Rubiano, C A Rios; Mitnik, D M; Silkin, V M; Gravielle, M S

    2016-01-01

    The influence of the crystallographic orientation of a typical metal surface, like aluminum, on electron emission spectra produced by grazing incidence of ultrashort laser pulses is investigated by using the band-structure-based-Volkov (BSB-V) approximation. The present version of the BSB-V approach includes not only a realistic description of the surface interaction, accounting for band structure effects, but also effects due to the induced potential that originates from the collective response of valence-band electrons to the external electromagnetic field. The model is applied to evaluate differential electron emission probabilities from the valence band of Al(100) and Al(111). For both crystallographic orientations, the contribution of partially occupied surface electronic states and the influence of the induced potential are separately analyzed as a function of the laser carrier frequency. We found that the induced potential strongly affects photoelectron emission distributions, opening a window to scrut...

  1. Crystallographic similarity between the lath martensite and lower bainite in medium-carbon alloy steels

    Institute of Scientific and Technical Information of China (English)

    LIU Jiangwen; LUO Chengping; WU Dongxiao

    2005-01-01

    Progress in the crystallography of lath martensitic and lower bainitic transformations is briefly reviewed, followed by a presentation of the experimentally measured crystallographic characteristics of both lath martensite and lower bainite formed in mediumcarbon steels containing Si, Mn and Mo. It is found that the bainite plates relate to each other by a relative rotation of 54.7°or 60°about the normal to their common close-packed planes {110} b, which ensures a pseudo- {112}b twin relationship between two adjacent plates,and that all bainite variants formed in a single packet keep a unique G-T orientation relationship with the austenite matrix. These two types of OR of lower bainite are similar to that of the lath martensite, respectively. Furthermore, the measured habit planes of both the lower bainite and lath martensite are all {335} f type, which can verify the crystallographic similarity between the lath martensite and lower bainite.

  2. Microstructure, crystallographic texture and mechanical properties of friction stir welded AA2017A

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, M.M.Z., E-mail: mohamed_ahmed4@s-petrol.suez.edu.eg [Institute for Microstructural and Mechanical Processing Engineering, University of Sheffield (IMMPETUS), Mappin Street, Sheffield S1 3JD (United Kingdom); Department of Metallurgical and Materials Engineering, Suez Canal University, Suez 43721 (Egypt); Wynne, B.P.; Rainforth, W.M. [Institute for Microstructural and Mechanical Processing Engineering, University of Sheffield (IMMPETUS), Mappin Street, Sheffield S1 3JD (United Kingdom); Threadgill, P.L. [TWI LTD, Granta Park, Great Abington, Cambridge CB21 6AL (United Kingdom)

    2012-02-15

    In this study a thick section (20 mm) friction stir welded AA2017A-T451 has been characterized in terms of microstructure, crystallographic texture and mechanical properties. For microstructural analysis both optical and scanning electron microscopes have been used. A detailed crystallographic texture analysis has been carried out using the electron back scattering diffraction technique. Crystallographic texture has been examined in both shoulder and probe affected regions of the weld NG. An entirely weak texture is observed at the shoulder affected region which is mainly explained by the effect of the sequential multi pass deformation experienced by both tool probe and tool shoulder. The texture in the probe dominated region at the AS side of the weld is relatively weak but still assembles the simple shear texture of FCC metals with B/B{sup Macron} and C components existing across the whole map. However, the texture is stronger at the RS than at the AS of the weld, mainly dominated byB/B{sup Macron} components and with C component almost absent across the map. An alternating bands between (B) components and (B{sup Macron }) component are observed only at the AS side of the weld. - Highlights: Black-Right-Pointing-Pointer Detailed investigation of microstructure and crystallographic texture. Black-Right-Pointing-Pointer The grain size is varied from the top to the bottom of the NG. Black-Right-Pointing-Pointer An entirely weak texture is observed at the shoulder affected region. Black-Right-Pointing-Pointer The texture in the probe affected region is dominated by simple shear texture.

  3. Crystallographic orientation-dependent pattern replication in direct imprint of aluminum nanostructures

    OpenAIRE

    2015-01-01

    In the present work, we perform molecular dynamics simulations corroborated by experimental validations to elucidate the underlying deformation mechanisms of single-crystalline aluminum under direct imprint using a rigid silicon master. We investigate the influence of crystallographic orientation on the microscopic deformation behavior of the substrate materials and its correlation with the macroscopic pattern replications. Furthermore, the surface mechanical properties of the patterned struc...

  4. Experimental and Theoretical Investigation of Crystallographic Orientation Dependence of Nanoscratching of Single Crystalline Copper

    OpenAIRE

    2015-01-01

    In the present work, we perform experiments and molecular dynamics simulations to elucidate the underlying deformation mechanisms of single crystalline copper under the load-controlled multi-passes nanoscratching using a triangular pyramidal probe. The correlation of microscopic deformation behavior of the material with macroscopically-observed machining results is revealed. Moreover, the influence of crystallographic orientation on the nanoscratching of single crystalline copper is examined....

  5. Crystallization and preliminary crystallographic characterization of an SH3 domain from the IB1 scaffold protein

    DEFF Research Database (Denmark)

    Dar, Imran; Bonny, Christophe; Pedersen, Jan Torleif

    2003-01-01

    with unmodified protein and deliberately oxidized protein have led to different crystal forms. X-ray data have been collected to 3.0 A resolution from a crystal form with rectangular prism morphology. These crystals are orthorhombic (P2(1)2(1)2(1)), with unit-cell parameters a = 45.9, b = 57.0, c = 145.5 A....... These are the first crystallographic data on a scaffold molecule such as IB1 to be reported....

  6. Keep it together: restraints in crystallographic refinement of macromolecule–ligand complexes

    Science.gov (United States)

    Steiner, Roberto A.; Tucker, Julie A.

    2017-01-01

    A short introduction is provided to the concept of restraints in macromolecular crystallographic refinement. A typical ligand restraint-generation process is then described, covering types of input, the methodology and the mechanics behind the software in general terms, how this has evolved over recent years and what to look for in the output. Finally, the currently available restraint-generation software is compared, concluding with some thoughts for the future. PMID:28177305

  7. Holistic design : learning from the Learning Centre

    Energy Technology Data Exchange (ETDEWEB)

    Simon, C. [Charles Simon Architect and Planner, Eden Mills, ON, (Canada); McKee, C. [Kitchener-Waterloo YMCA Outdoor Services, ON (Canada)

    2004-08-01

    The energy efficiency of several solar technologies currently in operation at the Kitchener-Waterloo YMCA's Environmental Learning Centre was evaluated. The off-grid earth-sheltered building dug into a south-facing slope features a sod roof, and protection from north winds by coniferous tree plantations. Passive solar strategies are evaluated, including average indoor temperatures and lighting requirements in both summer and winter. Also evaluated were the centre's ventilation systems, windows and passive heat recovery ventilators (HRVs), solar collectors, masonry heaters, and photovoltaic panels. The centre's composting toilets and use of the Living Machine{sup TM} were also discussed and details of the centre's building materials were provided. Ten straw-bale cabins are currently under construction at the centre, using passive solar strategies for heating, ventilation and cooling and combination propane fired/solar hot water heaters, straw bale building envelope and wood frame roof. Further suggestions for the centre's potential uses, and an outline of the centre's ongoing priorities were outlined. 4 refs.

  8. Affine extensions of non-crystallographic Coxeter groups induced by projection

    Science.gov (United States)

    Dechant, Pierre-Philippe; BÅ`hm, Céline; Twarock, Reidun

    2013-09-01

    In this paper, we show that affine extensions of non-crystallographic Coxeter groups can be derived via Coxeter-Dynkin diagram foldings and projections of affine extended versions of the root systems E8, D6, and A4. We show that the induced affine extensions of the non-crystallographic groups H4, H3, and H2 correspond to a distinguished subset of those considered in [P.-P. Dechant, C. Bœhm, and R. Twarock, J. Phys. A: Math. Theor. 45, 285202 (2012)]. This class of extensions was motivated by physical applications in icosahedral systems in biology (viruses), physics (quasicrystals), and chemistry (fullerenes). By connecting these here to extensions of E8, D6, and A4, we place them into the broader context of crystallographic lattices such as E8, suggesting their potential for applications in high energy physics, integrable systems, and modular form theory. By inverting the projection, we make the case for admitting different number fields in the Cartan matrix, which could open up enticing possibilities in hyperbolic geometry and rational conformal field theory.

  9. Electron diffraction study of {alpha}-AlMnSi crystals including non-crystallographic axes

    Energy Technology Data Exchange (ETDEWEB)

    Song, G.L.; Bursill, L.A.

    1997-06-01

    The structure of crystalline {alpha}-AlMnSi is examined by electron diffraction. Six distinct zone axes are examined, including both normal crystallographic and non-crystallographic zones axes, allowing the space group symmetry to be studied. Electron diffraction patterns characteristic of Pm3-bar were obtained for thicker specimens. However, for very thin specimens, as used for HRTEM imaging, the electron diffraction patterns were characteristic of Im3-bar space group symmetry. The structural basis of the Pm3-bar to Im3-bar transformation may be understood in terms of an analysis of the icosahedral structural elements located at the corners and body-centers of the cubic unit cell. A method for indexing the non-crystallographic zone axis diffraction patterns is described. An electron diffraction pattern of the 5-fold axis of the quasicrystalline phase i-AlMnSi is also included; this is compared with the experimental results and calculations for the [0{tau}1] axis of Pm3-bar and Im3-bar crystalline phases. 26 refs., 4 tabs., 7 figs.

  10. Rapid Creation of Three-Dimensional, Tactile Models from Crystallographic Data

    Directory of Open Access Journals (Sweden)

    Nathan B. Fisher

    2016-01-01

    Full Text Available A method for the conversion of crystallographic information framework (CIF files to stereo lithographic data files suitable for printing on three-dimensional printers is presented. Crystallographic information framework or CIF files are capable of being manipulated in virtual space by a variety of computer programs, but their visual representations are limited to the two-dimensional surface of the computer screen. Tactile molecular models that demonstrate critical ideas, such as symmetry elements, play a critical role in enabling new students to fully visualize crystallographic concepts. In the past five years, major developments in three-dimensional printing has lowered the cost and complexity of these systems to a level where three-dimensional molecular models may be easily created provided that the data exists in a suitable format. Herein a method is described for the conversion of CIF file data using existing free software that allows for the rapid creation of inexpensive molecular models. This approach has numerous potential applications in basic research, education, visualization, and crystallography.

  11. Inversion of the perturbation series

    Energy Technology Data Exchange (ETDEWEB)

    Amore, Paolo [Facultad de Ciencias, Universidad de Colima, Bernal DIaz del Castillo 340, Colima, Colima (Mexico); Fernandez, Francisco M [INIFTA (Conicet, UNLP), Division Quimica Teorica, Diag 113 S/N, Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina)

    2008-01-18

    We investigate the inversion of the perturbation series and its resummation, and prove that it is related to a recently developed parametric perturbation theory. Results for some illustrative examples show that in some cases series reversion may improve the accuracy of the results.

  12. Wave-equation dispersion inversion

    KAUST Repository

    Li, Jing

    2016-12-08

    We present the theory for wave-equation inversion of dispersion curves, where the misfit function is the sum of the squared differences between the wavenumbers along the predicted and observed dispersion curves. The dispersion curves are obtained from Rayleigh waves recorded by vertical-component geophones. Similar to wave-equation traveltime tomography, the complicated surface wave arrivals in traces are skeletonized as simpler data, namely the picked dispersion curves in the phase-velocity and frequency domains. Solutions to the elastic wave equation and an iterative optimization method are then used to invert these curves for 2-D or 3-D S-wave velocity models. This procedure, denoted as wave-equation dispersion inversion (WD), does not require the assumption of a layered model and is significantly less prone to the cycle-skipping problems of full waveform inversion. The synthetic and field data examples demonstrate that WD can approximately reconstruct the S-wave velocity distributions in laterally heterogeneous media if the dispersion curves can be identified and picked. The WD method is easily extended to anisotropic data and the inversion of dispersion curves associated with Love waves.

  13. Inverse Expander Mixing for Hypergraphs

    OpenAIRE

    Cohen, Emma; Mubayi, Dhruv; Ralli, Peter; Tetali, Prasad

    2014-01-01

    We formulate and prove inverse mixing lemmas in the settings of simplicial complexes and k-uniform hypergraphs. In the hypergraph setting, we extend results of Bilu and Linial for graphs. In the simplicial complex setting, our results answer a question of Parzanchevski et al.

  14. Geoacoustic inversion of ship radiated noise in shallow water using data from a single hydrophone.

    Science.gov (United States)

    Crocker, Steven E; Nielsen, Peter L; Miller, James H; Siderius, Martin

    2014-11-01

    The Centre for Maritime Research and Experimentation conducted a geoacoustic inverse experiment in the Mediterranean Sea in the summer of 2012. Among the objectives was to employ an autonomous underwater vehicle to collect acoustic data to invert for properties of the seafloor. Inversion results for the compression wave speed in the bottom and the source spectrum of the R/V Alliance during a close approach to the bottom moored vehicle are presented. The estimated wave speed was 1529 m/s (σ=10). The source spectrum of the Alliance was estimated across more than six octaves of frequency.

  15. New centre for intelligent mining systems

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, W.

    2002-10-01

    A Centre for Intelligent Mining Systems has been opened by the University of Alberta's Computing Science Department, a collaborative effort by the University and Syncrude Canada Ltd. The objective of the new Centre is to apply technologies in the area of artificial intelligence and robotics to the problems of surface mining. The Centre has already attracted attention from other players within the industry and a long-term funding proposal by a consortium that includes Syncrude is in the works. Noranda Inc and Inco Inc have also shown interest.

  16. Modelling total energy costs of sports centres

    Energy Technology Data Exchange (ETDEWEB)

    Boussabaine, A.H.; Kirkham, R.J.; Grew, R.J. [Liverpool Univ., School of Architecture and Building Engineering, Liverpool (United Kingdom)

    1999-12-07

    Providing and maintaining safe and comfortable conditions in sport centres raises many issues, particularly cost. The paper gives an overview of the factors associated with sport centre servicing and attempts to highlight the governing factors associated with this, particularly energy costs. A total of 19 sport centres in the City of Liverpool in the UK are investigated, using data elicited from the Liverpool Leisure Services Directorate. The energy operating costs were analysed using statistical methods. Six models were developed to predict total energy costs. Testing and validation results showed a high level of model accuracy. The models would be of use to professionals involved in feasibility studies at the design stage. (Author)

  17. Centre for human development, stem cells & regeneration.

    Science.gov (United States)

    Oreffo, Richard O C

    2014-01-01

    The Centre for Human Development, Stem Cells and Regeneration (CHDSCR) was founded in 2004 as a cross-disciplinary research and translational program within the Faculty of Medicine at the University of Southampton. The Centre undertakes fundamental research into early development and stem cells together with applied translational research for patient benefit. The Centre has vibrant and thriving multidisciplinary research programs that harness the translational strength of the Faculty together with an innovative Stem Cell PhD program, outstanding clinical infrastructure and enterprise to deliver on this vision.

  18. Review of CERN Data Centre Infrastructure

    CERN Document Server

    Andrade, P; van Eldik, J; McCance, G; Panzer-Steindel, B; Coelho dos Santos, M; Traylen, S; Schwickerath, U

    2012-01-01

    The CERN Data Centre is reviewing strategies for optimizing the use of the existing infrastructure and expanding to a new data centre by studying how other large sites are being operated. Over the past six months, CERN has been investigating modern and widely-used tools and procedures used for virtualisation, clouds and fabric management in order to reduce operational effort, increase agility and support unattended remote data centres. This paper gives the details on the project’s motivations, current status and areas for future investigation.

  19. Planetary Radars Operating Centre PROC

    Science.gov (United States)

    Catallo, C.; Flamini, E.; Seu, R.; Alberti, G.

    2007-12-01

    Planetary exploration by means of radar systems, mainly using Ground Penetrating Radars (GPR) plays an important role in Italy. Numerous scientific international space programs are currently carried out jointly with ESA and NASA by Italian Space Agency, the scientific community and the industry. Three important experiments under Italian leadership ( designed and manufactured by the Italian industry), provided by ASI either as contribution to ESA programs either within a NASA/ASI joint venture framework, are now operating: MARSIS on-board Mars Express, SHARAD on-board Mars Reconnaissance Orbiter and CASSINI Radar on-board Cassini spacecraft. In order to support all the scientific communities, institutional customers and experiment teams operation three Italian dedicated operational centers have been realized, namely SHOC, (Sharad Operating Centre), MOC (Marsis Operating Center) and CASSINI PAD ( Processing Altimetry Data). Each center is dedicated to a single instrument management and control, data processing and distribution. Although they had been conceived to operate autonomously and independently one from each other, synergies and overlaps have been envisaged leading to the suggestion of a unified center, the Planetary Radar Processing Center (PROC). PROC is conceived in order to include the three operational centers, namely SHOC, MOC and CASSINI PAD, either from logistics point of view and from HW/SW capabilities point of view. The Planetary Radar Processing Center shall be conceived as the Italian support facility to the scientific community for on-going and future Italian planetary exploration programs. Therefore, scalability, easy use and management shall be the design drivers. The paper describes how PROC is designed and developed, to allow SHOC, MOC and CASSINI PAD to operate as before, and to offer improved functionalities to increase capabilities, mainly in terms of data exchange, comparison, interpretation and exploitation. Furthermore, in the frame of

  20. Inverse and forward dynamics: models of multi-body systems.

    Science.gov (United States)

    Otten, E

    2003-01-01

    Connected multi-body systems exhibit notoriously complex behaviour when driven by external and internal forces and torques. The problem of reconstructing the internal forces and/or torques from the movements and known external forces is called the 'inverse dynamics problem', whereas calculating motion from known internal forces and/or torques and resulting reaction forces is called the 'forward dynamics problem'. When stepping forward to cross the street, people use muscle forces that generate angular accelerations of their body segments and, by virtue of reaction forces from the street, a forward acceleration of the centre of mass of their body. Inverse dynamics calculations applied to a set of motion data from such an event can teach us how temporal patterns of joint torques were responsible for the observed motion. In forward dynamics calculations we may attempt to create motion from such temporal patterns, which is extremely difficult, because of the complex mechanical linkage along the chains forming the multi-body system. To understand, predict and sometimes control multi-body systems, we may want to have mathematical expressions for them. The Newton-Euler, Lagrangian and Featherstone approaches have their advantages and disadvantages. The simulation of collisions and the inclusion of muscle forces or other internal forces are discussed. Also, the possibility to perform a mixed inverse and forward dynamics calculation are dealt with. The use and limitations of these approaches form the conclusion. PMID:14561340

  1. Workflows for Full Waveform Inversions

    Science.gov (United States)

    Boehm, Christian; Krischer, Lion; Afanasiev, Michael; van Driel, Martin; May, Dave A.; Rietmann, Max; Fichtner, Andreas

    2017-04-01

    Despite many theoretical advances and the increasing availability of high-performance computing clusters, full seismic waveform inversions still face considerable challenges regarding data and workflow management. While the community has access to solvers which can harness modern heterogeneous computing architectures, the computational bottleneck has fallen to these often manpower-bounded issues that need to be overcome to facilitate further progress. Modern inversions involve huge amounts of data and require a tight integration between numerical PDE solvers, data acquisition and processing systems, nonlinear optimization libraries, and job orchestration frameworks. To this end we created a set of libraries and applications revolving around Salvus (http://salvus.io), a novel software package designed to solve large-scale full waveform inverse problems. This presentation focuses on solving passive source seismic full waveform inversions from local to global scales with Salvus. We discuss (i) design choices for the aforementioned components required for full waveform modeling and inversion, (ii) their implementation in the Salvus framework, and (iii) how it is all tied together by a usable workflow system. We combine state-of-the-art algorithms ranging from high-order finite-element solutions of the wave equation to quasi-Newton optimization algorithms using trust-region methods that can handle inexact derivatives. All is steered by an automated interactive graph-based workflow framework capable of orchestrating all necessary pieces. This naturally facilitates the creation of new Earth models and hopefully sparks new scientific insights. Additionally, and even more importantly, it enhances reproducibility and reliability of the final results.

  2. Pareto joint inversion of 2D magnetotelluric and gravity data

    Science.gov (United States)

    Miernik, Katarzyna; Bogacz, Adrian; Kozubal, Adam; Danek, Tomasz; Wojdyła, Marek

    2015-04-01

    interesting density distributions are relatively shallow and resistivity changes are related to deeper parts. This kind of conditions are well suited for joint inversion of MT and gravity data. In the next stage of the solution development of further code optimization and extensive tests for real data will be realized. Presented work was supported by Polish National Centre for Research and Development under the contract number POIG.01.04.00-12-279/13

  3. Towards Human-Centred Design

    Science.gov (United States)

    Bannon, Liam J.

    The field of HCI has evolved and expanded dramatically since its origin in the early 1980’s. The HCI community embraces a large community of researchers and practitioners around the world, from a variety of disciplinary backgrounds in the human and social sciences, engineering and informatics, and more recently, the arts and design disciplines. This kaleidoscope of cultures and disciplines as seen at INTERACT Conferences provides a rich pool of resources for examining our field. Applications are increasingly exploring our full range of sensory modalities, and merging the digital and physical worlds. WiFi has opened up a huge design space for mobile applications. A focus on usability of products and services has been complemented by an emphasis on engagement, enjoyment and experience. With the advent of ubiquitous computing, and the emergence of “The Internet of Things”, new kinds of more open infrastructures make possible radically new kinds of applications. The sources of innovation have also broadened, to include human and social actors outside of the computing and design organizations. The question is to what extent is our mainstream thinking in the HCI field ready for the challenges of this Brave New World? Do the technological and social innovations that we see emerging require us to re-shape, or even, re-create, our field, or is it a case of a more gradual evolution and development of that which we already know? In this closing Keynote, I will provide a perspective on the evolution and development of the HCI field, looking backwards as well as forwards, in order to determine what are some of the changes of significance in the field. This “broad-brush” approach to what I term “ human-centred design” will be complemented by the examination of specific projects and applications, to help anchor some of the discussion. Areas such as user-centred design, participatory design, computer-supported cooperative work and learning, and interaction design, in

  4. Symmetric centres of braided monoidal categories

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper introduces the concept of‘symmetric centres' of braided monoidal categories. Let H be a Hopf algebra with bijective antipode over a field k. We address the symmetric centre of the Yetter-Drinfel'd module category HH(yD) and show that a left Yetter-Drinfel'd module M belongs to the symmetric centre of HH(yD) if and only if M is trivial. We also study the symmetric centres of categories of representations of quasitriangular Hopf algebras and give a sufficient and necessary condition for the braid of H(M) to induce the braid of (H(H)(A),(○)A,A,φ,l,r), or equivalently, the braid of (A#H(H),(○)A,A,φ,l,r), where A is a quantum commutative H-module algebra.

  5. Potential of Natural Ventilation in Shopping Centres

    DEFF Research Database (Denmark)

    Diederichsen, Alice; Friis, Kristina; Brohus, Henrik

    2008-01-01

    The indoor environmental quality (IEQ) is a fundamental requirement for a well performing shopping centre. This paper contains a pilot study of the potential of using hybrid ventilation (a combination of automatically controlled natural and mechanical ventilation - respectively NV and MV) in shop......The indoor environmental quality (IEQ) is a fundamental requirement for a well performing shopping centre. This paper contains a pilot study of the potential of using hybrid ventilation (a combination of automatically controlled natural and mechanical ventilation - respectively NV and MV......) in shopping centres with focus on both the achieved IEQ and energy consumptions for air movement. By thermal building simulations it is found that there exists an interesting potential for hybrid ventilation of shopping centres, which can lead to great savings in the electrical energy consumptions...

  6. Identity Theft: A Study in Contact Centres

    Science.gov (United States)

    Moir, Iain; Weir, George R. S.

    This paper explores the recent phenomenon of identity theft. In particular, it examines the contact centre environment as a mechanism for this to occur. Through a survey that was conducted amongst forty-five contact centre workers in the Glasgow area we determined that contact centres can and do provide a mechanism for identity theft. Specifically, we found a particularly high incidence of agents who had previously dealt with phone calls that they considered suspicious. Furthermore, there are agents within such environments who have previously been offered money in exchange for customers' details, or who know of fellow workers who received such offers. Lastly, we identify specific practices within contact centres that may contribute to the likelihood of identity theft.

  7. Social innovation for People-Centred Development

    DEFF Research Database (Denmark)

    Hulgård, Lars; P.K., Shajahan

    2013-01-01

    Social innovation is closely related to the people-centred development (PCD) framework of knowledge production. The discussion of PCD in this chapter particularly expands on the feature of empowerment and socio-political mobilization of people in social innovation......Social innovation is closely related to the people-centred development (PCD) framework of knowledge production. The discussion of PCD in this chapter particularly expands on the feature of empowerment and socio-political mobilization of people in social innovation...

  8. Perspectives on recycling centres and future developments.

    Science.gov (United States)

    Engkvist, I-L; Eklund, J; Krook, J; Björkman, M; Sundin, E

    2016-11-01

    The overall aim of this paper is to draw combined, all-embracing conclusions based on a long-term multidisciplinary research programme on recycling centres in Sweden, focussing on working conditions, environment and system performance. A second aim is to give recommendations for their development of new and existing recycling centres and to discuss implications for the future design and organisation. Several opportunities for improvement of recycling centres were identified, such as design, layout, ease with which users could sort their waste, the work environment, conflicting needs and goals within the industry, and industrialisation. Combining all results from the research, which consisted of different disciplinary aspects, made it possible to analyse and elucidate their interrelations. Waste sorting quality was recognized as the most prominent improvement field in the recycling centre system. The research identified the importance of involving stakeholders with different perspectives when planning a recycling centre in order to get functionality and high performance. Practical proposals of how to plan and build recycling centres are given in a detailed checklist.

  9. The Imperial College Thermophysical Properties Data Centre

    Science.gov (United States)

    Angus, S.; Cole, W. A.; Craven, R.; de Reuck, K. M.; Trengove, R. D.; Wakeham, W. A.

    1986-07-01

    The IUPAC Thermodynamic Tables Project Centre in London has at its disposal considerable expertise on the production and utilization of high-accuracy equations of state which represent the thermodynamic properties of substances. For some years they have been content to propagate this information by the traditional method of book production, but the increasing use of the computer in industry for process design has shown that an additional method was needed. The setting up of the IUPAC Transport Properties Project Centre, also at Imperial College, whose products would also be in demand by industry, afforded the occasion for a new look at the problem. The solution has been to set up the Imperial College Thermophysical Properties Data Centre, which embraces the two IUPAC Project Centres, and for it to establish a link with the existing Physical Properties Data Service of the Institution of Chemical Engineers, thus providing for the dissemination of the available information without involving the Centres in problems such as those of marketing and advertising. This paper outlines the activities of the Centres and discusses the problems in bringing their products to the attention of industry in suitable form.

  10. Ultrahigh-intensity inverse bremsstrahlung

    Science.gov (United States)

    Kostyukov, I. Yu.; Rax, J.-M.

    1999-01-01

    We study inverse bremsstrahlung in the ultrahigh intensity relativistic regime. The fully relativistic ultrahigh intensity absorption (emission) coefficient is derived for an arbitrary scattering potential and small-angle scattering. We find that in the Coulomb field case this absorption (emission) coefficient can be calculated as a function of the quiver energy, drift momentum, and impact parameter in two complementary regimes: (i) for remote collisions when the impact parameter is larger than the amplitude of the quiver motion, and (ii) for instantaneous collisions when the scattering time is shorter than the period of the wave. Both circular and linear polarizations are considered, and this study reveals that in this relativistic regime inverse bremsstrahlung absorption can be viewed as a harmonic Compton resonance heating of the laser-driven electron by the virtual photon of the ion Coulomb field. The relativistic modification of Marcuse's effect [Bell Syst. Tech. J. 41, 1557 (1962)] are also discussed, and relations with previous nonrelativistic results are elucidated.

  11. Analysis of RAE-1 inversion

    Science.gov (United States)

    Hedland, D. A.; Degonia, P. K.

    1974-01-01

    The RAE-1 spacecraft inversion performed October 31, 1972 is described based upon the in-orbit dynamical data in conjunction with results obtained from previously developed computer simulation models. The computer simulations used are predictive of the satellite dynamics, including boom flexing, and are applicable during boom deployment and retraction, inter-phase coast periods, and post-deployment operations. Attitude data, as well as boom tip data, were analyzed in order to obtain a detailed description of the dynamical behavior of the spacecraft during and after the inversion. Runs were made using the computer model and the results were analyzed and compared with the real time data. Close agreement between the actual recorded spacecraft attitude and the computer simulation results was obtained.

  12. Inverse imbalance reconstruction in rotordynamics

    Energy Technology Data Exchange (ETDEWEB)

    Ramlau, R. [Austrian Academy of Sciences, Linz (Austria). Johann Radon Inst. for Computational and Applied Mathematics; Dicken, V. [MeVis GmbH, Bremen (Germany); Maass, P. [Bremen Univ. (Germany). Zentrum fuer Technomathematik; Streller, C. [Rolls-Royce Germany GmbH, Dahlewitz (Germany); Rienaecker, A. [MTU Aero Engines GmbH, Muenchen (Germany)

    2006-05-15

    The goal of this work is to establish and compare algorithms for inverse imbalance reconstruction in aircraft turbines. Such algorithms are based on a validated whole engine model of a turbo engine under consideration. Base on the model, the impact of an imbalance distribution on the vibration behaviour of the turbine can be described as a matrix-vector multiplication Af = g, where f is the imbalance distribution and g the vibration response. It turns out that the matrix A is very ill-conditioned. As the measured data is highly affected with noise, we have to use regularization methods in order to stabilize the inversion. Our main interest was in the use of nonlinear regularization methods, in particular nonlinear filtered singular value decomposition and conjugate gradient regularization. (orig.)

  13. Broadband synthetic aperture geoacoustic inversion.

    Science.gov (United States)

    Tan, Bien Aik; Gerstoft, Peter; Yardim, Caglar; Hodgkiss, William S

    2013-07-01

    A typical geoacoustic inversion procedure involves powerful source transmissions received on a large-aperture receiver array. A more practical approach is to use a single moving source and/or receiver in a low signal to noise ratio (SNR) setting. This paper uses single-receiver, broadband, frequency coherent matched-field inversion and exploits coherently repeated transmissions to improve estimation of the geoacoustic parameters. The long observation time creates a synthetic aperture due to relative source-receiver motion. This approach is illustrated by studying the transmission of multiple linear frequency modulated (LFM) pulses which results in a multi-tonal comb spectrum that is Doppler sensitive. To correlate well with the measured field across a receiver trajectory and to incorporate transmission from a source trajectory, waveguide Doppler and normal mode theory is applied. The method is demonstrated with low SNR, 100-900 Hz LFM pulse data from the Shallow Water 2006 experiment.

  14. Sex Inversion Operations in China

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    IN July 1992, Dr. Xia Zhaoji, 58, and his assistants surprised the world by successfully completing the world’s first operation to partially replant human internal reproductive organs. BBC broadcast this 8-minute news story ten days later, followed by AP, Reuters and AFP, as well as some other domestic and international media. What is a sex inversion operation? Why should people change their sex? And how is it

  15. Inverse Gibbs-Thomson effect

    Science.gov (United States)

    Gershanov, V. Yu.; Garmashov, S. I.

    2015-01-01

    We prove the existence of an effect inverse to the Gibbs-Thomson effect for mass transfer in systems consisting of a solid phase and the solution of the solid phase material in a certain solvent. The effect involves a change in the shape of the interface due to a variation of the equilibrium concentrations under it, which is induced by external conditions, and exists in the presence of a negative feedback for mass transfer associated with capillary effects.

  16. Action understanding as inverse planning

    OpenAIRE

    Baker, Christopher Lawrence; Saxe, Rebecca R.; Joshua B Tenenbaum

    2009-01-01

    Humans are adept at inferring the mental states underlying other agents’ actions, such as goals, beliefs, desires, emotions and other thoughts. We propose a computational framework based on Bayesian inverse planning for modeling human action understanding. The framework represents an intuitive theory of intentional agents’ behavior based on the principle of rationality: the expectation that agents will plan approximately rationally to achieve their goals, given their beliefs about the world. ...

  17. Neglected puerperal inversion of the uterus

    African Journals Online (AJOL)

    abp

    2012-07-27

    Jul 27, 2012 ... Key words: Inversion of uterus, acute puerperal inversion, shock, post partum bleeding, neglect ... anesthesia, vaginal manual reposition was attempted, which failed due to tight cervical ring. Then, O .... Int J Gynecol Cancer.

  18. Identification of inversion domains in KTiOPO{sub 4}via resonant X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Fabrizi, Federica, E-mail: federica.fabrizi@diamond.ac.uk [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE (United Kingdom); Thomas, Pamela A. [Department of Physics, University of Warwick, Coventry, CV4 7AL (United Kingdom); Nisbet, Gareth; Collins, Stephen P. [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE (United Kingdom)

    2015-05-14

    The identification and high-resolution mapping of the absolute crystallographic structure in multi-domain ferroelectric KTiOPO{sub 4} is achieved through a novel synchrotron X-ray diffraction method. On a single Bragg reflection, the intensity ratio in resonant diffraction below and above the Ti absorption K edge demonstrates a domain contrast up to a factor of ∼270, thus implementing a non-contact, non-destructive imaging technique with micrometre spatial resolution, applicable to samples of arbitrarily large dimensions. A novel method is presented for the identification of the absolute crystallographic structure in multi-domain polar materials such as ferroelectric KTiOPO{sub 4}. Resonant (or ‘anomalous’) X-ray diffraction spectra collected across the absorption K edge of Ti (4.966 keV) on a single Bragg reflection demonstrate a huge intensity ratio above and below the edge, providing a polar domain contrast of ∼270. This allows one to map the spatial domain distribution in a periodically inverted sample, with a resolution of ∼1 µm achieved with a microfocused beam. This non-contact, non-destructive technique is well suited for samples of large dimensions (in contrast with traditional resonant X-ray methods based on diffraction from Friedel pairs), and its potential is particularly relevant in the context of physical phenomena connected with an absence of inversion symmetry, which require characterization of the underlying absolute atomic structure (such as in the case of magnetoelectric coupling and multiferroics)

  19. Generalized Inverses of Matrices over Rings

    Institute of Scientific and Technical Information of China (English)

    韩瑞珠; 陈建龙

    1992-01-01

    Let R be a ring,*be an involutory function of the set of all finite matrices over R. In this pa-per,necessary and sufficient conditions are given for a matrix to have a (1,3)-inverse,(1,4)-inverse,or Morre-Penrose inverse,relative to *.Some results about generalized inverses of matrices over division rings are generalized and improved.

  20. Transmission of HIV in dialysis centre.

    Science.gov (United States)

    Velandia, M; Fridkin, S K; Cárdenas, V; Boshell, J; Ramirez, G; Bland, L; Iglesias, A; Jarvis, W

    1995-06-01

    In August, 1993, 13 dialysis patients at one dialysis centre in Colombia, South America, were found to be HIV positive, and this prompted an epidemiological investigation. We carried out a cohort study of all dialysis centre patients during January, 1992 to December, 1993 (epidemic period) to determine risk factors for HIV seroconversion. Haemodialysis and medical records were reviewed, dialysis centre staff and surviving patients were interviewed, and dialysis practices were observed. Stored sera from all dialysis centre patients were tested for HIV antibody. 12 (52%) of 23 patients tested positive for HIV antibody by enzyme immunoassay and western blot during the epidemic period. Of the 23 tested, 9 (39%) converted from HIV antibody negative to positive (seroconverters) and 10 (44%) remained HIV negative (seronegatives). The HIV seroconversion rate was higher among patients dialysed at the centre while a new patient, who was HIV seropositive, was dialysed there (90% vs 0%; p dialysis centre reprocessed access needles, dialysers, and bloodlines (60% vs 0%). While 2 of 9 HIV seroconverters had had sex with prostitutes, none had received unscreened blood products or had other HIV risk factors. No surgical or dental procedures were associated with HIV seroconversion. Dialysers were reprocessed separately with 5% formaldehyde and were labelled for use on the same patient. Access needles were reprocessed by soaking them in a common container with a low-level disinfectant, benzalkonium chloride; 4 pairs of needles were placed in one pan creating the potential for cross-contamination or use of one patient's needles on another patient. HIV transmission at the dialysis centre was confirmed. Improperly reprocessed patient-care equipment, most probably access needles, is the likely mechanism of transmission. This outbreak was discovered by accident and similar transmission may be occurring in many other countries where low-level disinfectants are used to sterilise critical

  1. Inverse Computation and the Universal Resolving Algorithm

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    We survey fundamental concepts for inverse programming and thenpresent the Uni v ersal Resolving Algorithm, an algorithm for inverse computation in a first-orde r , functional programming language. We discuss the key concepts of the algorithm, including a three-step approach based on the notion of a perfect process tree, and demonstrate our implementation with several examples of inverse computation.

  2. -Colour even Self-Inverse Compositions

    Indian Academy of Sciences (India)

    Yu-hong Guo

    2010-02-01

    An -colour even self-inverse composition is defined as an -colour self-inverse composition with even parts. In this paper, we get generating functions, explicit formulas and recurrence formulas for -colour even self-inverse compositions. One new binomial identity is also obtained.

  3. Recombination rate predicts inversion size in Diptera.

    Science.gov (United States)

    Cáceres, M; Barbadilla, A; Ruiz, A

    1999-09-01

    Most species of the Drosophila genus and other Diptera are polymorphic for paracentric inversions. A common observation is that successful inversions are of intermediate size. We test here the hypothesis that the selected property is the recombination length of inversions, not their physical length. If so, physical length of successful inversions should be negatively correlated with recombination rate across species. This prediction was tested by a comprehensive statistical analysis of inversion size and recombination map length in 12 Diptera species for which appropriate data are available. We found that (1) there is a wide variation in recombination map length among species; (2) physical length of successful inversions varies greatly among species and is inversely correlated with the species recombination map length; and (3) neither the among-species variation in inversion length nor the correlation are observed in unsuccessful inversions. The clear differences between successful and unsuccessful inversions point to natural selection as the most likely explanation for our results. Presumably the selective advantage of an inversion increases with its length, but so does its detrimental effect on fertility due to double crossovers. Our analysis provides the strongest and most extensive evidence in favor of the notion that the adaptive value of inversions stems from their effect on recombination.

  4. Self-assembled ultra-nanocrystalline silicon films with preferred crystallographic orientation for solar cell applications

    Science.gov (United States)

    Banerjee, Amit; Das, Debajyoti

    2015-03-01

    Using low-pressure planar inductively coupled plasma CVD at 87% H2-dilution to the SiH4 plasma, nc-Si:H films are prepared that possess preferential growth along crystallographic orientation with I220/I111 > 1.2, bonded H-content of ∼5.5 at.%, a low microstructure factor of ∼0.56, along with a reasonably high σD ∼ 5.2 × 10-4 S cm-1, ΔE ∼ 143 meV and σPh ∼ 1.4 × 10-3 S cm-1. The growth of the nc-Si:H network has been optimized to a moderately high nanocrystallinity (∼68%), with an average grain size of ∼8 nm. The overall network comprises a significant fraction of ultra-nanocrystalline component, Xunc/Xnc ∼ 0.47, which are dominantly inhabited by the thermodynamically preferred crystallographic orientation that provides convenient electrical transport perpendicular to the film surface and subsequently could facilitate photovoltaic performance. The cross-sectional view of the fracture surface demonstrates columnar structures, closely correlated to the favored growth of the nanocrystallites along crystallographic orientation that retains direction perpendicular to the substrate surface. The underlying phenomena could be demonstrated as a consequence of preferential growth induced by high atomic H density present in the planar inductively coupled SiH4 plasma obtained via much lower H2-dilution compared to that realized in conventional capacitively coupled plasma-CVD. The nc-Si:H films with precise material properties as well as the allied low-pressure ICP-CVD growth process could be of significant use in further progress of nc-Si solar cells.

  5. Trapping of Oxygen Vacancies at Crystallographic Shear Planes in Acceptor-Doped Pb-Based Ferroelectrics.

    Science.gov (United States)

    Batuk, Dmitry; Batuk, Maria; Tsirlin, Alexander A; Hadermann, Joke; Abakumov, Artem M

    2015-12-01

    The defect chemistry of the ferroelectric material PbTiO3 after doping with Fe(III) acceptor ions is reported. Using advanced transmission electron microscopy and powder X-ray and neutron diffraction, we demonstrate that even at concentrations as low as circa 1.7% (material composition approximately ABO2.95), the oxygen vacancies are trapped into extended planar defects, specifically crystallographic shear planes. We investigate the evolution of these defects upon doping and unravel their detailed atomic structure using the formalism of superspace crystallography, thus unveiling their role in nonstoichiometry in the Pb-based perovskites.

  6. Crystallographic dependence of photocatalytic activity of WO3 thin films prepared by molecular beam epitaxy.

    Science.gov (United States)

    Li, Guoqiang; Varga, Tamas; Yan, Pengfei; Wang, Zhiguo; Wang, Chongmin; Chambers, Scott A; Du, Yingge

    2015-06-21

    We investigated the impact of crystallographic orientation on the photocatalytic activity of single crystalline WO3 thin films prepared by molecular beam epitaxy on the photodegradation of rhodamine B (RhB). A clear effect is observed, with (111) being the most reactive surface, followed by (110) and (001). Photoreactivity is directly correlated with the surface free energy determined by density functional theory calculations. The RhB photodegradation mechanism is found to involve hydroxyl radicals in solution formed from photo-generated holes and differs from previous studies performed on nanoparticles and composites.

  7. Regularities of crystallographic texture formation in cladding tubes from Zr-based alloys during their production

    Science.gov (United States)

    Isaenkova, M.; Perlovich, Yu; Fesenko, V.

    2016-04-01

    This paper summarizes researches of the authors, which are directed on the development of the methodological basis of X-ray studies in the materials science of zirconium and on the systematization of new experimental results obtained using developed methods. The paper describes regularities of the formation of the crystallographic texture and the substructure inhomogeneity of cladding tubes from zirconium alloys at various stages of their manufacturing, i.e. during hot and cold deformation, recrystallization, phase transformations and interactions of the above processes.

  8. (Fundamental studies of new magnetic heterostructures: Their growth, crystallographic structure, magnetic and electronic properties)

    Energy Technology Data Exchange (ETDEWEB)

    Onellion, M. (Wisconsin Univ., Madison, WI (USA). Dept. of Physics); Dowben, P.A. (Syracuse Univ., NY (USA). Dept. of Physics)

    1990-01-01

    As part of our request for renewal of our grant, we include this progress report on the significant results obtained under grant number FG02-89ER45319, Fundamental Studies of New Magnetic Heterostructures: Their Growth, Crystallographic Structure, Magnetic and Electronic Properties,'' since the inception of the grant. The results include the scientific accomplishments, the instrumentation developed, and the technological applications of our work. Each area is discussed separately and an initial summary of all areas is provided before the detailed discussion.

  9. Use of Bayesian Inference in Crystallographic Structure Refinement via Full Diffraction Profile Analysis

    Science.gov (United States)

    Fancher, Chris M.; Han, Zhen; Levin, Igor; Page, Katharine; Reich, Brian J.; Smith, Ralph C.; Wilson, Alyson G.; Jones, Jacob L.

    2016-01-01

    A Bayesian inference method for refining crystallographic structures is presented. The distribution of model parameters is stochastically sampled using Markov chain Monte Carlo. Posterior probability distributions are constructed for all model parameters to properly quantify uncertainty by appropriately modeling the heteroskedasticity and correlation of the error structure. The proposed method is demonstrated by analyzing a National Institute of Standards and Technology silicon standard reference material. The results obtained by Bayesian inference are compared with those determined by Rietveld refinement. Posterior probability distributions of model parameters provide both estimates and uncertainties. The new method better estimates the true uncertainties in the model as compared to the Rietveld method. PMID:27550221

  10. Morphological and crystallographic evolution of bainite transformation in Fe-0.15C binary alloy.

    Science.gov (United States)

    Zhang, Di; Terasaki, Hidenori; Komizo, Yuichi

    2010-01-01

    In this article, an in situ observation method, combining laser scanning confocal microscopy and electron backscattering diffraction, was used to investigate the morphological and crystallographic evolution of bainite transformation in a Fe-0.15C binary alloy. The nucleation at a grain boundary and inclusions, sympathetic nucleation, and impingement event of bainitic ferrite were directly shown in real time. The variant evolution during bainite transformation and misorientation between bainitic ferrites were clarified. Strong variant selection was observed during sympathetic nucleation. (c) 2009 Wiley-Liss, Inc.

  11. Visits to Tier-1 Computing Centres

    CERN Multimedia

    Dario Barberis

    At the beginning of 2007 it became clear that an enhanced level of communication is needed between the ATLAS computing organisation and the Tier-1 centres. Most usual meetings are ATLAS-centric and cannot address the issues of each Tier-1; therefore we decided to organise a series of visits to the Tier-1 centres and focus on site issues. For us, ATLAS computing management, it is most useful to realize how each Tier-1 centre is organised, and its relation to the associated Tier-2s; indeed their presence at these visits is also very useful. We hope it is also useful for sites... at least, we are told so! The usual participation includes, from the ATLAS side: computing management, operations, data placement, resources, accounting and database deployment coordinators; and from the Tier-1 side: computer centre management, system managers, Grid infrastructure people, network, storage and database experts, local ATLAS liaison people and representatives of the associated Tier-2s. Visiting Tier-1 centres (1-4). ...

  12. Scavenger hunt in the CERN Computing Centre

    CERN Multimedia

    CERN Bulletin

    2013-01-01

    Hidden among the racks of servers and disks in the CERN Computing Centre, you’ll find Hawaiian dancers, space aliens, gorillas… all LEGO® figurines! These characters were placed about the Centre for the arrival of Google’s Street View team for the world to discover.   PLEASE NOTE THAT THE COMPETITION IS OVER. ONLY FOR REFERENCE, HERE IS THE ORIGINAL ARTICLE. We’re pleased to announce our first global scavenger hunt! Spot three LEGO® figurines using Google’s Street View and you’ll be entered to win a gift of your choice from our CERN Gift Guide. A LEGO® figurine in the CERN Computing Centre, as seen on Google Street View. Here are the details: Find at least three LEGO® figurines hidden around the CERN Computing Centre using Google Street View.   Take screencaps of the figurines and e-mail the pictures to TreasureHunt-ComputingCentre@cern.ch. This email is no longer active.   The...

  13. The Aube centre. 1997 statement; Le centre de l`Aube. Bilan 1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-01

    Since January 1992 the Aube centre ensures the storage of 90% of the short life radioactive wastes produced in France. This educational booklet describes the organization of the activities in the centre from the storage of wastes to the radioactivity surveillance of the environment (air, surface and ground waters, river sediments, plants and milk). (J.S.)

  14. An algorithm for constructing minimal order inverses

    Science.gov (United States)

    Patel, R. V.

    1976-01-01

    In this paper an algorithm is presented for constructing minimal order inverses of linear, time invariant, controllable and observable, multivariable systems. By means of simple matrix operations, a 'state-overdescribed' system is first constructed which is an inverse of the given multivariable system. A simple Gauss-Jordan type reduction procedure is then used to remove the redundancy in the state vector of the inverse system to obtain a minimal order inverse. When the given multivariable system is not invertible, the algorithm enables a minimal order inverse of an invertible subsystem to be constructed. Numerical examples are given to illustrate the use of the algorithm.

  15. Reverse Universal Resolving Algorithm and inverse driving

    DEFF Research Database (Denmark)

    Pécseli, Thomas

    2012-01-01

    variant of the Universal Resolving Algorithm for inverse interpretation. The new variant outperforms the original algorithm in several cases, e.g., when unpacking a list using inverse interpretation of a pack program. It uses inverse driving as its main technique, which has not been described in detail......Inverse interpretation is a semantics based, non-standard interpretation of programs. Given a program and a value, an inverse interpreter finds all or one of the inputs, that would yield the given value as output with normal forward evaluation. The Reverse Universal Resolving Algorithm is a new...

  16. Inversion of GPS meteorology data

    Directory of Open Access Journals (Sweden)

    K. Hocke

    Full Text Available The GPS meteorology (GPS/MET experiment, led by the Universities Corporation for Atmospheric Research (UCAR, consists of a GPS receiver aboard a low earth orbit (LEO satellite which was launched on 3 April 1995. During a radio occultation the LEO satellite rises or sets relative to one of the 24 GPS satellites at the Earth's horizon. Thereby the atmospheric layers are successively sounded by radio waves which propagate from the GPS satellite to the LEO satellite. From the observed phase path increases, which are due to refraction of the radio waves by the ionosphere and the neutral atmosphere, the atmospheric parameter refractivity, density, pressure and temperature are calculated with high accuracy and resolution (0.5–1.5 km. In the present study, practical aspects of the GPS/MET data analysis are discussed. The retrieval is based on the Abelian integral inversion of the atmospheric bending angle profile into the refractivity index profile. The problem of the upper boundary condition of the Abelian integral is described by examples. The statistical optimization approach which is applied to the data above 40 km and the use of topside bending angle profiles from model atmospheres stabilize the inversion. The retrieved temperature profiles are compared with corresponding profiles which have already been calculated by scientists of UCAR and Jet Propulsion Laboratory (JPL, using Abelian integral inversion too. The comparison shows that in some cases large differences occur (5 K and more. This is probably due to different treatment of the upper boundary condition, data runaways and noise. Several temperature profiles with wavelike structures at tropospheric and stratospheric heights are shown. While the periodic structures at upper stratospheric heights could be caused by residual errors of the ionospheric correction method, the periodic temperature fluctuations at heights below 30 km are most likely caused by atmospheric waves (vertically

  17. A day in the CERN Control Centre

    CERN Multimedia

    Rosaria Marraffino

    2015-01-01

    The CERN Control Centre (CCC) is the nerve centre of the CERN beam systems. From this room, the experts prepare, monitor, adjust, and control the particle beams that circulate throughout the accelerator complex while ensuring that the services and the technical infrastructure work flawlessly. Buttons, screens, telephones, lights (but no sound): in the CCC, everything is ready to make it possible for the LHC to reach the unprecedented energies expected at Run 2.   Seen from above, the CERN Control Centre resembles the shape of a quadrupole magnet. The consoles are distributed in four circles, called “islands”, dedicated to the LHC, the SPS, the PS Complex and the Technical Infrastructure (TI) respectively. Spread between TI and LHC are the Cryogenics consoles. Being in the same room allows the 24h-manned islands to be constantly in touch with one another, thus ensuring the best performance of the machines. At the LHC island, operators are currently busy training the magnet...

  18. Information Centre Radioactivity Switzerland; Beratungsstelle Radioaktivitaet Schweiz

    Energy Technology Data Exchange (ETDEWEB)

    Mosimann, N.; Balsiger, B.; Burger, M. [Bundesamt fuer Bevoelkerungsschutz (Switzerland). LABOR SPIEZ

    2016-07-01

    The Information Centre Radioactivity Switzerland is meant to assess the radiological condition and serves for psychological-medical care of affected members of the Swiss public following an event of increased radioactivity in the environment. The Centre is structured in a modular way consisting of the following modules: ''Entry Measurement'': The visitors are registered and measured for contamination, ''Decontamination'': Contaminated visitors are decontaminated, ''Additional Measurements'': If required, thyroid and whole body measurements are performed, ''Information'': The visitors are informed about radioactivity, radiation protection, the current situation and their individual next steps, ''Exit'': Administrative release from the Information Centre.

  19. Occupational deprivation in an asylum centre:

    DEFF Research Database (Denmark)

    Morville, Anne-Le; Erlandsson, Lena-Karin

    2013-01-01

    This article presents a study of three asylum-seeking men from Iran and Afghanistan. It aimed to explore how and if they experienced occupations as occupations in a Danish asylum centre and how their life experience shaped their choice and value of current occupations. In-depth narrative interviews...... explored the participants’ occupational history and its influence on their occupations in the asylum centre. A thematic analysis showed that the participants had been subjected to occupational disruption and deprivation by politically oppressive systems even before their flight. Their occupations...... in Denmark were to a certain extent influenced by their earlier occupations and the current occupational deprivation they all experienced was due to limited possibilities in the centre. Although they tried their best to fill their days and create structure, there was a loss of valued occupations...

  20. Learning Styles of Independent Learning Centre Users

    Directory of Open Access Journals (Sweden)

    Tarik Uzun

    2014-09-01

    Full Text Available Learning style research has been a significant field within language teaching and learning. There have been very few attempts, however, to seek possible links between independent learning and learning style preferences. This paper aims to identify the learning styles of students who use the Independent Learning Centre (ILC on a regular basis at a state university in Turkey (n=102. The findings of the learning style analysis revealed that, contrary to expectations, most of the regular users of the centre were synoptic learners, which implies that these learners might not necessarily have conscious control over their own learning processes. An in-depth analysis of learning styles and recommendations to improve the services offered in the centre are also included in the paper.

  1. Inverse Star, Borders, and Palstars

    OpenAIRE

    Rampersad, Narad; Shallit, Jeffrey; Wang, Ming-Wei

    2010-01-01

    A language L is closed if L = L*. We consider an operation on closed languages, L-*, that is an inverse to Kleene closure. It is known that if L is closed and regular, then L-* is also regular. We show that the analogous result fails to hold for the context-free languages. Along the way we find a new relationship between the unbordered words and the prime palstars of Knuth, Morris, and Pratt. We use this relationship to enumerate the prime palstars, and we prove that neither the language of a...

  2. Spray formation: an inverse cascade

    CERN Document Server

    Ling, Yue; Tryggvason, Gretar; zaleski, Stephane

    2015-01-01

    We present a study of droplet formation in a gas-liquid mixing layer using direct numerical simulation. It is seen that two mechanisms compete to generate the droplets: fingering at the tip of the waves and hole formation in the thin liquid sheet. The three dimensional liquid structures are much shorter than the longitudinal wavelength of the instability at the first instant of their formation. As time evolves, the structures evolves to larger and larger scales, in a way similar to the inverse cascade of length scales in droplet impact and impact crown formation.

  3. Iterative optimization in inverse problems

    CERN Document Server

    Byrne, Charles L

    2014-01-01

    Iterative Optimization in Inverse Problems brings together a number of important iterative algorithms for medical imaging, optimization, and statistical estimation. It incorporates recent work that has not appeared in other books and draws on the author's considerable research in the field, including his recently developed class of SUMMA algorithms. Related to sequential unconstrained minimization methods, the SUMMA class includes a wide range of iterative algorithms well known to researchers in various areas, such as statistics and image processing. Organizing the topics from general to more

  4. The Inverse of Banded Matrices

    Science.gov (United States)

    2013-01-01

    of Br,n. For these sequences to be well-defined, we assume that none of the denominators kis are zero (which is equivalent to the below-defined U...numbers of summed or subtracted terms in computing the inverse of a term of an upper (lower) triangular matrix are the generalized order-k Fibonacci ... Fibonacci numbers are the usual Fibonacci numbers, that is, f 2m = Fm (mth Fibonacci number). When also k = 3, c1 = c2 = c3 = 1, then the generalized order-3

  5. Optimizing Data Centre Energy and Environmental Costs

    Science.gov (United States)

    Aikema, David Hendrik

    Data centres use an estimated 2% of US electrical power which accounts for much of their total cost of ownership. This consumption continues to grow, further straining power grids attempting to integrate more renewable energy. This dissertation focuses on assessing and reducing data centre environmental and financial costs. Emissions of projects undertaken to lower the data centre environmental footprints can be assessed and the emission reduction projects compared using an ISO-14064-2-compliant greenhouse gas reduction protocol outlined herein. I was closely involved with the development of the protocol. Full lifecycle analysis and verifying that projects exceed business-as-usual expectations are addressed, and a test project is described. Consuming power when it is low cost or when renewable energy is available can be used to reduce the financial and environmental costs of computing. Adaptation based on the power price showed 10--50% potential savings in typical cases, and local renewable energy use could be increased by 10--80%. Allowing a fraction of high-priority tasks to proceed unimpeded still allows significant savings. Power grid operators use mechanisms called ancillary services to address variation and system failures, paying organizations to alter power consumption on request. By bidding to offer these services, data centres may be able to lower their energy costs while reducing their environmental impact. If providing contingency reserves which require only infrequent action, savings of up to 12% were seen in simulations. Greater power cost savings are possible for those ceding more control to the power grid operator. Coordinating multiple data centres adds overhead, and altering at which data centre requests are processed based on changes in the financial or environmental costs of power is likely to increase this overhead. Tests of virtual machine migrations showed that in some cases there was no visible increase in power use while in others power use

  6. THE ELUSIVENESS OF LEARNER-CENTRED TEACHING

    Directory of Open Access Journals (Sweden)

    Ervin Kovačević

    2016-03-01

    Full Text Available This research will explore teaching styles of university professors. Teaching style is an umbrella term for teaching decisions made during the entire teaching process – planning, delivery, and evaluation. Contemporary university teachers are advised to adopt the learner-centred teaching style which is assumed to produce remarkable possibilities. In the Fall Semester 2015 fifty-two respondents in different faculties of International University of Sarajevo were surveyed using The Principles of Adult Learning Scale inventory designed by Gary J. Conti. Inventory scores were calculated according to guidelines suggested by the author of the inventory. The scores revealed that majority of respondents strongly supported teacher-centred rather than learner-centred styles of instruction. Scores were analysed on gender lines and across three different faculties, namely: Arts and Social Sciences; Business and Administration; Engineering and Natural Sciences. In all five groups none of the seven teaching style indicators was found to conform with the learner-centred teaching criteria. There was no statistically significant difference between the two genders’ preference for a teaching style. And there was no statistically significant difference between teaching style preference across the three different faculties.The results of this research imply that the learner-centred style of instruction is not frequently implemented. Secondly, the results indicate that the requirements necessary for proper application of the learner-centred teaching style are not easy to meet in current written and unwritten norms. Finally, the results show that traditional teaching styles, which have been preserved in different scientific fields, still predominate in universities.

  7. High resolution 3D nonlinear integrated inversion

    Institute of Scientific and Technical Information of China (English)

    Li Yong; Wang Xuben; Li Zhirong; Li Qiong; Li Zhengwen

    2009-01-01

    The high resolution 3D nonlinear integrated inversion method is based on nonlinear theory. Under layer control, the log data from several wells (or all wells) in the study area and seismic trace data adjacent to the wells are input to a network with multiple inputs and outputs and are integratedly trained to obtain an adaptive weight function of the entire study area. Integrated nonlinear mapping relationships are built and updated by the lateral and vertical geologic variations of the reservoirs. Therefore, the inversion process and its inversion results can be constrained and controlled and a stable seismic inversion section with high resolution with velocity inversion, impedance inversion, and density inversion sections, can be gained. Good geologic effects have been obtained in model computation tests and real data processing, which verified that this method has high precision, good practicality, and can be used for quantitative reservoir analysis.

  8. Byurakan Astrophysical Observatory as Cultural Centre

    Science.gov (United States)

    Mickaelian, A. M.; Farmanyan, S. V.

    2016-12-01

    NAS RA V. Ambartsumian Byurakan Astrophysical Observatory is presented as a cultural centre for Armenia and the Armenian nation in general. Besides being scientific and educational centre, the Observatory is famous for its unique architectural ensemble, rich botanical garden and world of birds, as well as it is one of the most frequently visited sightseeing of Armenia. In recent years, the Observatory has also taken the initiative of the coordination of the Cultural Astronomy in Armenia and in this field, unites the astronomers, historians, archaeologists, ethnographers, culturologists, literary critics, linguists, art historians and other experts.

  9. Byurakan Astrophysical Observatory as Cultural Centre

    Science.gov (United States)

    Mickaelian, A. M.; Farmanyan, S. V.

    2017-07-01

    NAS RA V. Ambartsumian Byurakan Astrophysical Observatory is presented as a cultural centre for Armenia and the Armenian nation in general. Besides being scientific and educational centre, the Observatory is famous for its unique architectural ensemble, rich botanical garden and world of birds, as well as it is one of the most frequently visited sightseeing of Armenia. In recent years, the Observatory has also taken the initiative of the coordination of the Cultural Astronomy in Armenia and in this field, unites the astronomers, historians, archaeologists, ethnographers, culturologists, literary critics, linguists, art historians and other experts. Keywords: Byurakan Astrophysical Observatory, architecture, botanic garden, tourism, Cultural Astronomy.

  10. Enhancing person-centred communication in NICU

    DEFF Research Database (Denmark)

    Weis, Janne; Zoffmann, Vibeke; Egerod, Ingrid

    2015-01-01

    Aims of this article were (a) to explore how parents of premature infants experience guided family-centred care (GFCC), and (b) to compare how parents receiving GFCC versus standard care (SC) describe nurse-parent communication in the neonatal intensive care unit.......Aims of this article were (a) to explore how parents of premature infants experience guided family-centred care (GFCC), and (b) to compare how parents receiving GFCC versus standard care (SC) describe nurse-parent communication in the neonatal intensive care unit....

  11. Seismic Waveform Inversion Using the Finite-Difference Contrast Source Inversion Method

    OpenAIRE

    Bo Han; Qinglong He; Yong Chen; Yixin Dou

    2014-01-01

    This paper extends the finite-difference contrast source inversion method to reconstruct the mass density for two-dimensional elastic wave inversion in the framework of the full-waveform inversion. The contrast source inversion method is a nonlinear iterative method that alternatively reconstructs contrast sources and contrast function. One of the most outstanding advantages of this inversion method is the highly computational efficiency, since it does not need to simulate a fu...

  12. Magnetic transition temperatures follow crystallographic symmetry in samarium under high-pressures and low-temperatures

    Science.gov (United States)

    Johnson, Craig R.; Tsoi, Georgiy M.; Vohra, Yogesh K.

    2017-02-01

    Magnetic ordering temperatures in rare earth metal samarium (Sm) have been studied using an ultrasensitive electrical transport measurement technique in a designer diamond anvil cell to high-pressure up to 47 GPa and low-temperature to 10 K. The two magnetic transitions at 106 K and 14 K in the α-Sm phase, attributed to antiferromagnetic ordering on hexagonal and cubic layers respectively, collapse in to one magnetic transition near 10 GPa when Sm assumes a double hexagonal close packed (dhcp) phase. On further increase in pressure above 34 GPa, the magnetic transitions split again as Sm adopts a hexagonal-hP3 structure indicating different magnetic transition temperatures for different crystallographic sites. A model for magnetic ordering for the hexagonal-hP3 phase in samarium has been proposed based on the experimental data. The magnetic transition temperatures closely follow the crystallographic symmetry during α-Sm  →  dhcp  →  fcc/dist.fcc  →  hP3 structure sequence at high-pressures and low-temperatures.

  13. Erbium-ion implantation into various crystallographic cuts of Al2O3

    Science.gov (United States)

    Nekvindova, P.; Mackova, A.; Malinsky, P.; Cajzl, J.; Svecova, B.; Oswald, J.; Wilhelm, R. A.

    2015-12-01

    This paper reports on the importance of crystallographic cuts with a different orientation on the luminescent properties and structural changes of Al2O3 implanted with Er+ ions at 190 keV and with a fluence of 1.0 × 1016 cm-2. Post-implantation annealing at 1000 °C in oxygen atmosphere was also done. The chemical compositions and erbium concentration-depth profiles of implanted layers were studied by Rutherford Backscattering Spectrometry (RBS) and compared to SRIM simulations. The same value of the maximum erbium concentration (up to 2 at.%) was observed at a depth of about 40 nm for all crystallographic cuts. The structural properties of the prepared layers were characterised by RBS/channelling. The relative amount of disordered atoms of 70-80% was observed in the prepared implanted layers and discussed for various cuts. It has been found that erbium is positioned randomly in the Al2O3 crystalline matrix, and no preferential positions appeared even after the annealing procedure. Erbium luminescence properties were measured in the wavelength range of 1440-1650 nm for all samples. As-implanted Al2O3 samples had a significant luminescence band at 1530 nm. The best luminescence was repeatedly observed in the cut of Al2O3. The annealing procedure significantly improved the luminescent properties.

  14. Crystallographic structure of Ni-Co coating on the affinity adsorption of histidine-tagged protein.

    Science.gov (United States)

    Chang, Yaw-Jen; Chen, Sheng-Zheng; Ho, Ching-Yuan

    2015-04-01

    The principle of immobilized metal affinity chromatography (IMAC) has been recently implemented for protein microarrays for the study of protein abundance and function. Ni-Co film fabricated by electrodeposition is a novel microarray surface in an alloy type for immobilizing histidine-tagged proteins based on IMAC. In this paper, the effects of crystallographic structures and surface properties of Ni-Co coatings, with and without the annealing process, on the immobilization of histidine-tagged proteins were systematically investigated. The experimental results reveal that the stronger hcp texture, due to a higher Co content, results in better affinity adsorption for histidine-tagged biotin. Nevertheless, the allotropic phase transformation from hcp to fcc, due to the annealing process, leads to the decrease of affinity adsorption. The wettability property and the surface roughness of Ni-Co coating are, however, not important factors. Obviously, the crystallographic structure of Ni-Co coating is the dominant factor for the specific affinity adsorption of histidine-tagged protein.

  15. Crystallographic superstructure in R2PdSi3 compounds (R=heavy rare earth)

    Science.gov (United States)

    Tang, Fei; Frontzek, Matthias; Dshemuchadse, Julia; Leisegang, Tilmann; Zschornak, Matthias; Mietrach, Robert; Hoffmann, Jens-Uwe; Löser, Wolfgang; Gemming, Sibylle; Meyer, Dirk C.; Loewenhaupt, Michael

    2011-09-01

    The R2PdSi3 intermetallic compounds have been reported to crystallize in a hexagonal AlB2-derived structure, with the rare earth atoms on the Al sites and Pd and Si atoms randomly distributed on the B sites. However, the intricate magnetic properties observed in the series of compounds have always suggested complications to the assumed structure. To clarify the situation, x-ray and neutron diffraction measurements were performed on the heavy rare earth compounds with R=Gd, Tb, Dy, Ho, Er, Tm, which revealed the existence of a crystallographic superstructure. The superstructure features a doubled unit cell in the hexagonal basal plane and an octuplication along the perpendicular c direction with respect to the primitive cell. No structural transition was observed between 300 and 1.5 K. Extended x-ray absorption fine structure (EXAFS) analysis as well as density functional theory (DFT) calculations were utilized to investigate the local environments of the respective atoms. In this paper the various experimental results will be presented and it will be shown that the superstructure is mainly due to the Pd-Si order on the B sites. A structure model will be proposed to fully describe the superstructure of Pd-Si order in R2PdSi3. The connection between the crystallographic superstructure and the magnetic properties will be discussed in the framework of the presented model.

  16. Reaction temperature variations on the crystallographic state of spinel cobalt aluminate.

    Science.gov (United States)

    Taguchi, Minori; Nakane, Takayuki; Hashi, Kenjiro; Ohki, Shinobu; Shimizu, Tadashi; Sakka, Yoshio; Matsushita, Akiyuki; Abe, Hiroya; Funazukuri, Toshitaka; Naka, Takashi

    2013-05-21

    In this study, we report a rapid and simple technique for obtaining cobalt aluminate having a spinel structure. The products were prepared from a hydroxide precursor synthesized by coprecipitation of cobalt (Co(2+)) and aluminum (Al(3+)) nitrates with an alkaline solution. The chosen precursor enabled low temperature fabrication of cobalt aluminate with a spinel structure by sintering it for 2 hours at low temperatures (>400 °C). Crystallographic and thermal analyses suggest that the low-temperature-sintered products contain Co(3+) ions stabilized by chemisorbed water and/or hydroxide groups, which was not observed for products sintered at temperatures higher than 1000 °C. The color of the products turned from clear blue (Thenard's blue) to dark green when sintering temperatures were below 1000 °C. Magnetic quantities, Curie constants, and Weiss temperatures show a strong dependence on the sintering temperature. These findings suggest that there are mixed valent states, i.e. Co(2+) and Co(3+), and unique cation distributions at the different crystallographic sites in the spinel structure, especially in the products sintered at lower temperatures.

  17. Synthesis of crystallographically oriented olivine aggregates using colloidal processing in a strong magnetic field

    Science.gov (United States)

    Koizumi, Sanae; Suzuki, Tohru S.; Sakka, Yoshio; Yabe, Kosuke; Hiraga, Takehiko

    2016-11-01

    This study develops a fabrication technique to obtain Fe-free and Fe-bearing (Fe:Mg = 1:9) olivine aggregates not only with high density and fine grain size but with crystallographic preferred orientation (CPO). A magnetic field (≤12 T) is applied to synthetic, fine-grained ( 120 nm), olivine particles dispersed in solvent. The alignment of certain crystallographic axes of the particles with respect to a magnetic direction is anticipated due to magnetic anisotropy of olivine. The dispersed particles are gradually consolidated on a porous alumina mold covered with a solid-liquid separation filter during drainage of the solvent. The resultant aligned consolidated aggregate is then isostatically pressed and vacuum sintered. We find that (1) preparation of fully reacted olivine particles, with less propensity to coalesce; (2) preparation of a suspension with highly dispersed particles; and (3) application of a certain strength of the magnetic field are essential to obtain well-sintered and well-aligned aggregates. High density (i.e., olivine aggregates were successfully synthesized with uniaxially aligned a- and c-axes, respectively. Attempts to uniaxially align the magnetization hard axis and to triaxially align Fe-bearing olivine by rotating the suspension in the magnetic field succeeded in obtaining weakly developed CPO aggregates.

  18. Crystallographic and electronic properties of AlCrN films that absorb visible light

    Science.gov (United States)

    Tatemizo, N.; Imada, S.; Miura, Y.; Nishio, K.; Isshiki, T.

    2017-05-01

    We investigate the crystallographic and electronic properties of wurtzite Cr-doped AlN (AlCrN) films (Cr ≤12.0%) that absorb visible light. We confirmed that the films consist of wurtzite columnar single crystals that are densely packed, c-axis oriented, and exhibit a random rotation along the a-axis in plane by using transmission electron microscopy. The oxidation state of Cr was found to be 3+ using Cr K-edge X-ray absorption near edge structure, which implies that Cr can be a substitute for Al3+ in AlN. The first nearest neighbor distances estimated using Cr K-edge extended X-ray absorption fine structure (EXAFS) were found to be nearly isotropic for incident light with electric fields that are parallel and perpendicular to the plane. The results of ab initio lattice relaxation calculations for the model of wurtzite Al1-xCrxN supercell where Cr replaces Al support the EXAFS results. The calculations for the model showed that additional energy bands are formed in the band gap of AlN, in which the Fermi energy (EF) is present. As expected from the calculation results, the electrical conductivity increases with increase in the Cr concentration, implying that the density of states at EF increases monotonically. From these results, we can conclude that AlCrN films are an intermediate band material with respect to their crystallographic and electric properties.

  19. Determination of precise crystallographic directions for mask alignment in wet bulk micromachining for MEMS

    Science.gov (United States)

    Singh, Sajal Sagar; Pal, Prem; Pandey, Ashok Kumar; Xing, Yan; Sato, Kazuo

    2016-12-01

    In wet bulk micromachining, the etching characteristics are orientation dependent. As a result, prolonged etching of mask openings of any geometric shape on both Si{100} and Si{110} wafers results in a structure defined by the slowest etching planes. In order to fabricate microstructures with high dimensional accuracy, it is vital to align the mask edges along the crystal directions comprising of these slowest etching planes. Thus, precise alignment of mask edges is important in micro/nano fabrication. As a result, the determination of accurate crystal directions is of utmost importance and is in fact the first step to ensure dimensionally accurate microstructures for improved performance. In this review article, we have presented a comprehensive analysis of different techniques to precisely determine the crystallographic directions. We have covered various techniques proposed in the span of more than two decades to determine the crystallographic directions on both Si{100} and Si{110} wafers. Apart from a detailed discussion of each technique along with their design and implementation, we have provided a critical analysis of the associated constraints, benefits and shortcomings. We have also summed up the critical aspects of each technique and presented in a tabular format for easy reference for readers. This review article comprises of an exhaustive discussion and is a handy reference for researchers who are new in the field of wet anisotropic etching or who want to get abreast with the techniques of determination of crystal directions.

  20. Conformation-changing aggregation in hydroxyacetone: a combined low-temperature FTIR, jet, and crystallographic study.

    Science.gov (United States)

    Sharma, Archna; Reva, Igor; Fausto, Rui; Hesse, Susanne; Xue, Zhifeng; Suhm, Martin A; Nayak, Susanta K; Sathishkumar, Ranganthan; Pal, Rumpa; Row, Tayur N Guru

    2011-12-21

    Aggregation in hydroxyacetone (HA) is studied using low-temperature FTIR, supersonic jet expansion, and X-ray crystallographic (in situ cryocrystallization) techniques. Along with quantum chemical methods (MP2 and DFT), the experiments unravel the conformational preferences of HA upon aggregation to dimers and oligomers. The O-H···O═C intramolecular hydrogen bond present in the gas-phase monomer partially opens upon aggregation in supersonic expansions, giving rise to intermolecular cooperatively enhanced O-H···O-H hydrogen bonds in competition with isolated O-H···O═C hydrogen bonds. On the other hand, low-temperature IR studies on the neat solid and X-ray crystallographic data reveal that HA undergoes profound conformational changes upon crystallization, with the HOCC dihedral angle changing from ~0° in the gas phase to ~180° in the crystalline phase, hence giving rise to a completely new conformation. These conclusions are supported by theoretical calculations performed on the geometry derived from the crystalline phase. © 2011 American Chemical Society

  1. Acanthamoeba polyphaga mimivirus NDK: preliminary crystallographic analysis of the first viral nucleoside diphosphate kinase

    Energy Technology Data Exchange (ETDEWEB)

    Jeudy, Sandra [Information Génomique et Structurale, CNRS UPR 2589, 31 Chemin Joseph Aiguier, 13402 Marseille CEDEX 20 (France); Coutard, Bruno [Architecture et Fonction des Macromolecules Biologiques, CNRS UMR 6098, 31 Chemin Joseph Aiguier, 13402 Marseille CEDEX 20 (France); Lebrun, Régine [IBSM, 31 Chemin Joseph Aiguier, 13402 Marseille CEDEX 20 (France); Abergel, Chantal, E-mail: chantal.abergel@igs.cnrs-mrs.fr [Information Génomique et Structurale, CNRS UPR 2589, 31 Chemin Joseph Aiguier, 13402 Marseille CEDEX 20 (France)

    2005-06-01

    A. polyphaga mimivirus, the largest known double-stranded DNA virus, is the first virus to exhibit a nucleoside diphosphate kinase gene. The expression and crystallization of the viral NDK are reported. The complete sequence of the largest known double-stranded DNA virus, Acanthamoeba polyphaga mimivirus, has recently been determined [Raoult et al. (2004 ▶), Science, 306, 1344–1350] and revealed numerous genes not expected to be found in a virus. A comprehensive structural and functional study of these gene products was initiated [Abergel et al. (2005 ▶), Acta Cryst. F61, 212–215] both to better understand their role in the virus physiology and to obtain some clues to the origin of DNA viruses. Here, the preliminary crystallographic analysis of the viral nucleoside diphosphate kinase protein is reported. The crystal belongs to the cubic space group P2{sub 1}3, with unit-cell parameter 99.425 Å. The self-rotation function confirms that there are two monomers per asymmetric unit related by a twofold non-crystallographic axis and that the unit cell thus contains four biological entities.

  2. The fourth crystallographic closest packing unveiled in the gold nanocluster crystal

    Science.gov (United States)

    Gan, Zibao; Chen, Jishi; Wang, Juan; Wang, Chengming; Li, Man-Bo; Yao, Chuanhao; Zhuang, Shengli; Xu, An; Li, Lingling; Wu, Zhikun

    2017-03-01

    Metal nanoclusters have recently attracted extensive interest not only for fundamental scientific research, but also for practical applications. For fundamental scientific research, it is of major importance to explore the internal structure and crystallographic arrangement. Herein, we synthesize a gold nanocluster whose composition is determined to be Au60S6(SCH2Ph)36 by using electrospray ionization mass spectrometry and single crystal X-ray crystallography (SCXC). SCXC also reveals that Au60S6(SCH2Ph)36 consists of a fcc-like Au20 kernel protected by a pair of giant Au20S3(SCH2Ph)18 staple motifs, which contain 6 tetrahedral-coordinate μ4-S atoms not previously reported in the Au-S interface. Importantly, the fourth crystallographic closest-packed pattern, termed 6H left-handed helical (6HLH) arrangement, which results in the distinct loss of solid photoluminescence of amorphous Au60S6(SCH2Ph)36, is found in the crystals of Au60S6(SCH2Ph)36. The solvent-polarity-dependent solution photoluminescence is also demonstrated. Overall, this work provides important insights about the structure, Au-S bonding and solid photoluminescence of gold nanoclusters.

  3. Evaluating Free Energies of Binding and Conservation of Crystallographic Waters Using SZMAP.

    Science.gov (United States)

    Bayden, Alexander S; Moustakas, Demetri T; Joseph-McCarthy, Diane; Lamb, Michelle L

    2015-08-24

    The SZMAP method computes binding free energies and the corresponding thermodynamic components for water molecules in the binding site of a protein structure [ SZMAP, 1.0.0 ; OpenEye Scientific Software Inc. : Santa Fe, NM, USA , 2011 ]. In this work, the ability of SZMAP to predict water structure and thermodynamic stability is examined for the X-ray crystal structures of a series of protein-ligand complexes. SZMAP results correlate with higher-level replica exchange thermodynamic integration double decoupling calculations of the absolute free energy of bound waters in the test set complexes. In addition, SZMAP calculations show good agreement with experimental data in terms of water conservation (across multiple crystal structures) and B-factors over a subset of the test set. In particular, the SZMAP neutral entropy difference term calculated at crystallographic water positions within each of the complex structures correlates well with whether that crystallographic water is conserved or displaceable. Furthermore, the calculated entropy of the water probe relative to the continuum shows a significant degree of correlation with the B-factors associated with the oxygen atoms of the water molecules. Taken together, these results indicate that SZMAP is capable of quantitatively predicting water positions and their energetics and is potentially a useful tool for determining which waters to attempt to displace, maintain, or build in through water-mediated interactions when evolving a lead series during a drug discovery program.

  4. Development of Microstructure and Crystallographic Texture in a Double-Sided Friction Stir Welded Microalloyed Steel

    Science.gov (United States)

    Rahimi, S.; Wynne, B. P.; Baker, T. N.

    2017-01-01

    The evolution of microstructure and crystallographic texture has been investigated in double-sided friction stir welded microalloyed steel, using electron backscatter diffraction (EBSD). The microstructure analyses show that the center of stirred zone reached a temperature between Ac1 and Ac3 during FSW, resulting in a dual-phase austenitic/ ferritic microstructure. The temperatures in the thermo-mechanically affected zone and the overlapped area between the first and second weld pass did not exceed the Ac1. The shear generated by the rotation probe occurs in austenitic/ferritic phase field where the austenite portion of the microstructure is transformed to a bainitic ferrite, on cooling. Analysis of crystallographic textures with regard to shear flow lines generated by the probe tool shows the dominance of simple shear components across the whole weld. The austenite texture at Ac1 - Ac3 is dominated by the B { {1bar{1}2} }stirred zone and the ferrites in the thermo-mechanically affected zones and the overlapped area underwent shear deformation with textures dominated by the D1 { {bar{1}bar{1}2} }weld pass. This is due to continuous dynamic strain-induced recrystallization as a result of simultaneous severe shear deformation and drastic undercooling.

  5. Enhancing nanoscale SEM image segmentation and reconstruction with crystallographic orientation data and machine learning

    Energy Technology Data Exchange (ETDEWEB)

    Converse, Matthew I., E-mail: mconverse85@yahoo.com; Fullwood, David T.

    2013-09-15

    Current methods of image segmentation and reconstructions from scanning electron micrographs can be inadequate for resolving nanoscale gaps in composite materials (1–20 nm). Such information is critical to both accurate material characterizations and models of piezoresistive response. The current work proposes the use of crystallographic orientation data and machine learning for enhancing this process. It is first shown how a machine learning algorithm can be used to predict the connectivity of nanoscale grains in a Nickel nanostrand/epoxy composite. This results in 71.9% accuracy for a 2D algorithm and 62.4% accuracy in 3D. Finally, it is demonstrated how these algorithms can be used to predict the location of gaps between distinct nanostrands — gaps which would otherwise not be detected with the sole use of a scanning electron microscope. - Highlights: • A method is proposed for enhancing the segmentation/reconstruction of SEM images. • 3D crystallographic orientation data from a nickel nanocomposite is collected. • A machine learning algorithm is used to detect trends in adjacent grains. • This algorithm is then applied to predict likely regions of nanoscale gaps. • These gaps would otherwise be unresolved with the sole use of an SEM.

  6. CRYSNET manual. Informal report. [Hardware and software of crystallographic computing network

    Energy Technology Data Exchange (ETDEWEB)

    None,

    1976-07-01

    This manual describes the hardware and software which together make up the crystallographic computing network (CRYSNET). The manual is intended as a users' guide and also provides general information for persons without any experience with the system. CRYSNET is a network of intelligent remote graphics terminals that are used to communicate with the CDC Cyber 70/76 computing system at the Brookhaven National Laboratory (BNL) Central Scientific Computing Facility. Terminals are in active use by four research groups in the field of crystallography. A protein data bank has been established at BNL to store in machine-readable form atomic coordinates and other crystallographic data for macromolecules. The bank currently includes data for more than 20 proteins. This structural information can be accessed at BNL directly by the CRYSNET graphics terminals. More than two years of experience has been accumulated with CRYSNET. During this period, it has been demonstrated that the terminals, which provide access to a large, fast third-generation computer, plus stand-alone interactive graphics capability, are useful for computations in crystallography, and in a variety of other applications as well. The terminal hardware, the actual operations of the terminals, and the operations of the BNL Central Facility are described in some detail, and documentation of the terminal and central-site software is given. (RWR)

  7. The Structural Biology Center 19ID undulator beamline: facility specifications and protein crystallographic results.

    Science.gov (United States)

    Rosenbaum, Gerd; Alkire, Randy W; Evans, Gwyndaf; Rotella, Frank J; Lazarski, Krzystof; Zhang, Rong Guang; Ginell, Stephan L; Duke, Norma; Naday, Istvan; Lazarz, Jack; Molitsky, Michael J; Keefe, Lisa; Gonczy, John; Rock, Larry; Sanishvili, Ruslan; Walsh, Martin A; Westbrook, Edwin; Joachimiak, Andrzej

    2006-01-01

    The 19ID undulator beamline of the Structure Biology Center has been designed and built to take full advantage of the high flux, brilliance and quality of X-ray beams delivered by the Advanced Photon Source. The beamline optics are capable of delivering monochromatic X-rays with photon energies from 3.5 to 20 keV (3.5-0.6 A wavelength) with fluxes up to 8-18 x 10(12) photons s(-1) (depending on photon energy) onto cryogenically cooled crystal samples. The size of the beam (full width at half-maximum) at the sample position can be varied from 2.2 mm x 1.0 mm (horizontal x vertical, unfocused) to 0.083 mm x 0.020 mm in its fully focused configuration. Specimen-to-detector distances of between 100 mm and 1500 mm can be used. The high flexibility, inherent in the design of the optics, coupled with a kappa-geometry goniometer and beamline control software allows optimal strategies to be adopted in protein crystallographic experiments, thus maximizing the chances of their success. A large-area mosaic 3 x 3 CCD detector allows high-quality diffraction data to be measured rapidly to the crystal diffraction limits. The beamline layout and the X-ray optical and endstation components are described in detail, and the results of representative crystallographic experiments are presented.

  8. Mode decomposition based on crystallographic symmetry in the band-unfolding method

    Science.gov (United States)

    Ikeda, Yuji; Carreras, Abel; Seko, Atsuto; Togo, Atsushi; Tanaka, Isao

    2017-01-01

    The band-unfolding method is widely used to calculate the effective band structures of a disordered system from its supercell model. The unfolded band structures show the crystallographic symmetry of the underlying structure, where the difference of chemical components and the local atomic relaxation are ignored. However, it has still been difficult to decompose the unfolded band structures into the modes based on the crystallographic symmetry of the underlying structure, and therefore detailed analyses of the unfolded band structures have been restricted. In this study, a procedure to decompose the unfolded band structures according to the small representations (SRs) of the little groups is developed. The decomposition is performed using the projection operators for SRs derived from the group representation theory. The current method is employed to investigate the phonon band structure of disordered face-centered-cubic Cu0.75Au0.25 , which has large variations of atomic masses and force constants among the atomic sites due to the chemical disorder. In the unfolded phonon band structure, several peculiar behaviors such as discontinuous and split branches are found in the decomposed modes corresponding to specific SRs. They are found to occur because different combinations of the chemical elements contribute to different regions of frequency.

  9. LHC Report: 2 inverse femtobarns!

    CERN Document Server

    Mike Lamont for the LHC Team

    2011-01-01

    The LHC is enjoying a confluence of twos. This morning (Friday 5 August) we passed 2 inverse femtobarns delivered in 2011; the peak luminosity is now just over 2 x1033 cm-2s-1; and recently fill 2000 was in for nearly 22 hours and delivered around 90 inverse picobarns, almost twice 2010's total.   In order to increase the luminosity we can increase of number of bunches, increase the number of particles per bunch, or decrease the transverse beam size at the interaction point. The beam size can be tackled in two ways: either reduce the size of the injected bunches or squeeze harder with the quadrupole magnets situated on either side of the experiments. Having increased the number of bunches to 1380, the maximum possible with a 50 ns bunch spacing, a one day meeting in Crozet decided to explore the other possibilities. The size of the beams coming from the injectors has been reduced to the minimum possible. This has brought an increase in the peak luminosity of about 50% and the 2 x 1033 cm...

  10. Inverse problems and inverse scattering of plane waves

    CERN Document Server

    Ghosh Roy, Dilip N

    2001-01-01

    The purpose of this text is to present the theory and mathematics of inverse scattering, in a simple way, to the many researchers and professionals who use it in their everyday research. While applications range across a broad spectrum of disciplines, examples in this text will focus primarly, but not exclusively, on acoustics. The text will be especially valuable for those applied workers who would like to delve more deeply into the fundamentally mathematical character of the subject matter.Practitioners in this field comprise applied physicists, engineers, and technologists, whereas the theory is almost entirely in the domain of abstract mathematics. This gulf between the two, if bridged, can only lead to improvement in the level of scholarship in this highly important discipline. This is the book''s primary focus.

  11. [Accreditation criteria and quality standards for Poisons centres: development of a quality management system within the Milan Poisons centre].

    Science.gov (United States)

    Della Puppa, Tiziana; Manfrè, Sergio; Grezzi, Marinella

    2006-01-01

    Poisons centres throughout Italy and Europe vary considerably in terms of their institutions and organisation. The European Association of Poisons Centres and Clinical Toxicologists (EAPCCT) has laid down the activities that a poisons centre must carry out, specifying minimum and maximum standards required. These directions allow an evaluation of the service provided. In 2002 Milan Poisons Centre began a project aiming to introduce concepts and methodology proper of the quality systems within poisons centres' institutional activity. Concluded, the project resulted in the centre's certification and the documentation of its procedures: this may now contribute to help define the status and activity of poisons centres in Italy.

  12. Constrained and joint inversion on unstructured meshes

    Science.gov (United States)

    Doetsch, J.; Jordi, C.; Rieckh, V.; Guenther, T.; Schmelzbach, C.

    2015-12-01

    Unstructured meshes allow for inclusion of arbitrary surface topography, complex acquisition geometry and undulating geological interfaces in the inversion of geophysical data. This flexibility opens new opportunities for coupling different geophysical and hydrological data sets in constrained and joint inversions. For example, incorporating geological interfaces that have been derived from high-resolution geophysical data (e.g., ground penetrating radar) can add geological constraints to inversions of electrical resistivity data. These constraints can be critical for a hydrogeological interpretation of the inversion results. For time-lapse inversions of geophysical data, constraints can be derived from hydrological point measurements in boreholes, but it is difficult to include these hard constraints in the inversion of electrical resistivity monitoring data. Especially mesh density and the regularization footprint around the hydrological point measurements are important for an improved inversion compared to the unconstrained case. With the help of synthetic and field examples, we analyze how regularization and coupling operators should be chosen for time-lapse inversions constrained by point measurements and for joint inversions of geophysical data in order to take full advantage of the flexibility of unstructured meshes. For the case of constraining to point measurements, it is important to choose a regularization operator that extends beyond the neighboring cells and the uncertainty in the point measurements needs to be accounted for. For joint inversion, the choice of the regularization depends on the expected subsurface heterogeneity and the cell size of the parameter mesh.

  13. [The coordination of care in health centres].

    Science.gov (United States)

    Ribardière, Olivia

    2016-06-01

    Health centres are structurally designed to facilitate the coordination of care. However, evolutions in society have resulted in forms of consumption of health care which are not necessarily compatible with efficient care coordination. On a local level, teams are nevertheless organising and structuring themselves to offer the right form of care, to the right patient and at the right time.

  14. Renovation of the CERN Computer Centre

    CERN Multimedia

    Patrice Loïez

    2003-01-01

    The Computer Centre at CERN is seen after half of the equipment is the large ground floor room has been removed. A large-scale spring-cleaning operation took place before renovation work for the new CERN Grid system began. Fifteen kilometres of cables that were no longer needed were removed from the cavity floor for recycling.

  15. Visiting a science centre: what's on offer?

    Science.gov (United States)

    Russell, Ian

    1990-09-01

    Science centres are a valuable resource, used more frequently by family groups and primary school parties than by secondary schools. The importance of affective learning, involving attitude changes, is stressed. Provided the right approach is used, accompanying adults can help children get the most out of a visit.

  16. Tensions in human-centred design

    NARCIS (Netherlands)

    Steen, M.G.D.

    2011-01-01

    In human-centred design (HCD), researchers and designers attempt to cooperate with and learn from potential users of the products or services which they are developing. Their goal is to develop products or services that match users' practices, needs and preferences. In this position paper it is argu

  17. Centre de formació virtual

    OpenAIRE

    Mòdol Martínez, Oscar

    2012-01-01

    Treball de fi de carrera en .NET sobre un centre de formació virtual, desenvolupat en la plataforma .NET amb ASP.NET, VB.NET i Windows Phone 7. Trabajo de fin de carrera en .NET sobre un centro de formación virtual, desarrollado en la plataforma .NET con ASP.NET, VB.NET y Windows Phone 7.

  18. Self Assessment and Student-Centred Learning

    Science.gov (United States)

    McDonald, Betty

    2012-01-01

    This paper seeks to show how self assessment facilitates student-centred learning (SCL) and fills a gap in the literature. Two groups of students were selected from a single class in a tertiary educational institution. The control group of 25 was selected randomly by the tossing of an unbiased coin (heads = control group). They were trained in the…

  19. Student-Centred Learning: A Humanist Perspective

    Science.gov (United States)

    Tangney, Sue

    2014-01-01

    The notion of student-centred learning is often not defined; within the pedagogic literature it is generally associated with constructivism or principles associated with a constructivist environment such as building on prior knowledge, purposeful active learning and sense-making. An informal enquiry into conceptions of university staff prior to…

  20. Patient-centred tuberculosis treatment in Tanzania

    NARCIS (Netherlands)

    Mkopi, A.B.

    2015-01-01

    The main aim of this thesis was to describe and assess the efficacy of the Patient-Centred Treatment (PCT) strategy for the delivery and supervision of tuberculosis (TB) treatment as implemented by the National Tuberculosis and Leprosy programme of Tanzania. The studies presented in this thesis show

  1. Youth Research Centre Annual Report, 2002.

    Science.gov (United States)

    Melbourne Univ. (Australia). Youth Research Centre.

    This report details the activities of the Youth Research Centre (YRC) at the University of Melbourne in 2002 in research project work involving a balance between the completion of projects, the development of new areas, and the continuation of longer-term projects as well as the supervision and teaching of a range of postgraduate health and…

  2. Mandibular trauma: a two-centre study

    NARCIS (Netherlands)

    Boffano, P.; Kommers, S.C.; Karagozoglu, K.H.; Gallesio, C.; Forouzanfar, T.

    2015-01-01

    The aims of this study were to assess and compare epidemiological data on mandibular fractures from two European centres and to perform a review of the literature. Between 2001 and 2010, a total of 752 patients with a total of 1167 mandibular fractures were admitted to a hospital in Turin, and 245 p

  3. Regional Dermatology Training Centre in Moshi, Tanzania ...

    African Journals Online (AJOL)

    31 No. 7. Regional Dermatology Training Centre in Moshi, Tanzania – pursuing a dream ... little training in the management of skin disease.[1] ... through lack of trained personnel or resources ... With time, other facilities such as a library, a pharmaceutical compounding ... of information on dermatology and STIs in a tropical ...

  4. Flexible Processes in Project-Centred Learning

    NARCIS (Netherlands)

    Ceri, Stefano; Matera, Maristella; Raffio, Alessandro; Spoelstra, Howard

    2007-01-01

    Ceri, S., Matera, M., Raffio, A. & Spoelstra, H. (2007). Flexible Processes in Project-Centred Learning. In E. Duval, R. Klamma, and M. Wolpers (Eds.), European Conference on Technology Enhanced Learning, Lecture Notes in Computer Science, Vol. 4753, pp. 463-468. Berlin Heidelberg: Springer-Verlag

  5. Myanmar: The Community Learning Centre Experience.

    Science.gov (United States)

    Middelborg, Jorn; Duvieusart, Baudouin, Ed.

    A community learning centre (CLC) is a local educational institution outside the formal education system, usually set up and managed by local people. CLCs were first introduced in Myanmar in 1994, and by 2001 there were 71 CLCs in 11 townships. The townships are characterized by remoteness, landlessness, unemployment, dependency on one cash crop,…

  6. Cactus: The Centres of a Triangle

    Science.gov (United States)

    Hyde, Hartley

    2009-01-01

    This is the first of two articles which describe how to use "JavaSketchPad" to explore the centres of a triangle. This introductory exercise is suggested in the GSP "Workshop Guide". Students can use "JavaSketchPad Interactive Geometry" (JSP) at home at no cost. They are likely to impress their parents with their enthusiasm for geometry and all…

  7. The INTEGRAL science data centre (ISDC)

    DEFF Research Database (Denmark)

    Courvoisier, T.J.L.; Walter, Rasmus; Beckmann, V.

    2003-01-01

    The INTEGRAL Science Data Centre (ISDC) provides the INTEGRAL data and means to analyse them to the scientific community. The ISDC runs a gamma ray burst alert system that provides the position of gamma ray bursts on the sky within seconds to the community. It operates a quick-look analysis...

  8. Solution for Ill-Posed Inverse Kinematics of Robot Arm by Network Inversion

    Directory of Open Access Journals (Sweden)

    Takehiko Ogawa

    2010-01-01

    Full Text Available In the context of controlling a robot arm with multiple joints, the method of estimating the joint angles from the given end-effector coordinates is called inverse kinematics, which is a type of inverse problems. Network inversion has been proposed as a method for solving inverse problems by using a multilayer neural network. In this paper, network inversion is introduced as a method to solve the inverse kinematics problem of a robot arm with multiple joints, where the joint angles are estimated from the given end-effector coordinates. In general, inverse problems are affected by ill-posedness, which implies that the existence, uniqueness, and stability of their solutions are not guaranteed. In this paper, we show the effectiveness of applying network inversion with regularization, by which ill-posedness can be reduced, to the ill-posed inverse kinematics of an actual robot arm with multiple joints.

  9. Person-centred care in nursing documentation.

    LENUS (Irish Health Repository)

    Broderick, Margaret C

    2012-12-07

    BACKGROUND: Documentation is an essential part of nursing. It provides evidence that care has been carried out and contains important information to enhance the quality and continuity of care. Person-centred care (PCC) is an approach to care that is underpinned by mutual respect and the development of a therapeutic relationship between the patient and nurse. It is a core principle in standards for residential care settings for older people and is beneficial for both patients and staff (International Practice Development in Nursing and Healthcare, Chichester, Blackwell, 2008 and The Implementation of a Model of Person-Centred Practice in Older Person Settings, Dublin, Health Service Executive, 2010a). However, the literature suggests a lack of person-centredness within nursing documentation (International Journal of Older People Nursing 2, 2007, 263 and The Implementation of a Model of Person-Centred Practice in Older Person Settings, Dublin, Health Service Executive, 2010a). AIMS AND OBJECTIVES: To explore nursing documentation in long-term care, to determine whether it reflected a person-centred approach to care and to describe aspects of PCC as they appeared in nursing records. METHOD: A qualitative descriptive study using the PCN framework (Person-centred Nursing; Theory and Practice, Oxford, Wiley-Blackwell, 2010) as the context through which nursing assessments and care plans were explored. RESULTS: Findings indicated that many nursing records were incomplete, and information regarding psychosocial aspects of care was infrequent. There was evidence that nurses engaged with residents and worked with their beliefs and values. However, nursing documentation was not completed in consultation with the patient, and there was little to suggest that patients were involved in decisions relating to their care. IMPLICATIONS FOR PRACTICE: The structure of nursing documentation can be a major obstacle to the recording of PCC and appropriate care planning. Documentation

  10. Wake Vortex Inverse Model User's Guide

    Science.gov (United States)

    Lai, David; Delisi, Donald

    2008-01-01

    NorthWest Research Associates (NWRA) has developed an inverse model for inverting landing aircraft vortex data. The data used for the inversion are the time evolution of the lateral transport position and vertical position of both the port and starboard vortices. The inverse model performs iterative forward model runs using various estimates of vortex parameters, vertical crosswind profiles, and vortex circulation as a function of wake age. Forward model predictions of lateral transport and altitude are then compared with the observed data. Differences between the data and model predictions guide the choice of vortex parameter values, crosswind profile and circulation evolution in the next iteration. Iterations are performed until a user-defined criterion is satisfied. Currently, the inverse model is set to stop when the improvement in the rms deviation between the data and model predictions is less than 1 percent for two consecutive iterations. The forward model used in this inverse model is a modified version of the Shear-APA model. A detailed description of this forward model, the inverse model, and its validation are presented in a different report (Lai, Mellman, Robins, and Delisi, 2007). This document is a User's Guide for the Wake Vortex Inverse Model. Section 2 presents an overview of the inverse model program. Execution of the inverse model is described in Section 3. When executing the inverse model, a user is requested to provide the name of an input file which contains the inverse model parameters, the various datasets, and directories needed for the inversion. A detailed description of the list of parameters in the inversion input file is presented in Section 4. A user has an option to save the inversion results of each lidar track in a mat-file (a condensed data file in Matlab format). These saved mat-files can be used for post-inversion analysis. A description of the contents of the saved files is given in Section 5. An example of an inversion input

  11. Statistical Inversion of Seismic Noise Inversion statistique du bruit sismique

    Directory of Open Access Journals (Sweden)

    Adler P. M.

    2006-11-01

    Full Text Available A systematic investigation of wave propagation in random media is presented. Spectral analysis, inversion of codas and attenuation of the direct wave front are studied for synthetic data obtained in isotropic or anisotropic, 2D or 3D media. A coda inversion process is developed and checked on two sets of real data. In both cases, it is possible to compare the correlation lengths obtained by inversion to characteristic lengths measured on seismic logs, for the full scale seismic survey, or on a thin section, for the laboratory experiment. These two experiments prove the feasibility and the efficiency of the statistical inversion of codas. Correct characteristic lengths can be obtained which cannot be determined by another method. Le problème de la géophysique est la recherche d'informations concernant le sous-sol, dans des signaux sismiques enregistrés en surface ou dans des puits. Ces informations sont habituellement recherchées sous forme déterministe, c'est-à-dire sous la forme de la donnée en chaque point d'une valeur du paramètre étudié. Notre point de vue est différent puisque notre objectif est de déduire certaines propriétés statistiques du milieu, supposé hétérogène, à partir des sismogrammes enregistrés après propagation. Il apparaît alors deux moyens de remplir l'objectif fixé. Le premier est l'analyse spectrale des codas ; cette analyse permet de déterminer les tailles moyennes des hétérogénéités du sous-sol. La deuxième possibilité est l'étude de l'atténuation du front direct de l'onde, qui conduit aussi à la connaissance des longueurs caractéristiques du sous-sol ; contrairement à la première méthode, elle ne semble pas pouvoir être transposée efficacement à des cas réels. Dans la première partie, on teste numériquement la proportionnalité entre le facteur de rétrodiffraction, relié aux propriétés statistiques du milieu, et le spectre des codas. Les distributions de vitesse, à valeur

  12. Bayesian multitask inverse reinforcement learning

    CERN Document Server

    Dimitrakakis, Christos

    2011-01-01

    We generalise the problem of inverse reinforcement learning to multiple tasks, from a set of demonstrations. Each demonstration may represent one expert trying to solve a different task. Alternatively, one may see each demonstration as given by a different expert trying to solve the same task. Our main technical contribution is to solve the problem by formalising it as statistical preference elicitation, via a number of structured priors, whose form captures our biases about the relatedness of different tasks or expert policies. We show that our methodology allows us not only to learn to efficiently from multiple experts but to also effectively differentiate between the goals of each. Possible applications include analysing the intrinsic motivations of subjects in behavioural experiments and imitation learning from multiple teachers.

  13. Inverse Diffusion Theory of Photoacoustics

    CERN Document Server

    Bal, Guillaume

    2009-01-01

    This paper analyzes the reconstruction of diffusion and absorption parameters in an elliptic equation from knowledge of internal data. In the application of photo-acoustics, the internal data are the amount of thermal energy deposited by high frequency radiation propagating inside a domain of interest. These data are obtained by solving an inverse wave equation, which is well-studied in the literature. We show that knowledge of two internal data based on well-chosen boundary conditions uniquely determines two constitutive parameters in diffusion and Schroedinger equations. Stability of the reconstruction is guaranteed under additional geometric constraints of strict convexity. No geometric constraints are necessary when $2n$ internal data for well-chosen boundary conditions are available, where $n$ is spatial dimension. The set of well-chosen boundary conditions is characterized in terms of appropriate complex geometrical optics (CGO) solutions.

  14. Inverse Transport Theory of Photoacoustics

    CERN Document Server

    Bal, Guillaume; Jugnon, Vincent

    2009-01-01

    We consider the reconstruction of optical parameters in a domain of interest from photoacoustic data. Photoacoustic tomography (PAT) radiates high frequency electromagnetic waves into the domain and measures acoustic signals emitted by the resulting thermal expansion. Acoustic signals are then used to construct the deposited thermal energy map. The latter depends on the constitutive optical parameters in a nontrivial manner. In this paper, we develop and use an inverse transport theory with internal measurements to extract information on the optical coefficients from knowledge of the deposited thermal energy map. We consider the multi-measurement setting in which many electromagnetic radiation patterns are used to probe the domain of interest. By developing an expansion of the measurement operator into singular components, we show that the spatial variations of the intrinsic attenuation and the scattering coefficients may be reconstructed. We also reconstruct coefficients describing anisotropic scattering of ...

  15. Inverse Magnetic/Shear Catalysis

    CERN Document Server

    McInnes, Brett

    2015-01-01

    It is well known that very large magnetic fields are generated when the Quark-Gluon Plasma is formed during peripheral heavy-ion collisions. Lattice, holographic, and other studies strongly suggest that these fields may, for observationally relevant field values, induce ``inverse magnetic catalysis'', signalled by a lowering of the critical temperature for the chiral/deconfinement transition. The theoretical basis of this effect has recently attracted much attention; yet so far these investigations have not included another, equally dramatic consequence of the peripheral collision geometry: the QGP acquires a large angular momentum vector, parallel to the magnetic field. Here we use holographic techniques to argue that the angular momentum can also, independently, have an effect on transition temperatures, and we obtain a rough estimate of the relative effects of the presence of both a magnetic field and an angular momentum density. We find that the shearing angular momentum reinforces the effect of the magne...

  16. Optimization and inverse problems in electromagnetism

    CERN Document Server

    Wiak, Sławomir

    2003-01-01

    From 12 to 14 September 2002, the Academy of Humanities and Economics (AHE) hosted the workshop "Optimization and Inverse Problems in Electromagnetism". After this bi-annual event, a large number of papers were assembled and combined in this book. During the workshop recent developments and applications in optimization and inverse methodologies for electromagnetic fields were discussed. The contributions selected for the present volume cover a wide spectrum of inverse and optimal electromagnetic methodologies, ranging from theoretical to practical applications. A number of new optimal and inverse methodologies were proposed. There are contributions related to dedicated software. Optimization and Inverse Problems in Electromagnetism consists of three thematic chapters, covering: -General papers (survey of specific aspects of optimization and inverse problems in electromagnetism), -Methodologies, -Industrial Applications. The book can be useful to students of electrical and electronics engineering, computer sci...

  17. Effect of crystallographic orientation on hillock formation in thermally cycled large grain tin films

    Science.gov (United States)

    Koppes, John Patrick

    Tin whiskers and hillocks grow spontaneously from the surfaces of polycrystalline Sn films at room temperature. Whiskers can grow long enough to cause short circuits in electronic devices. We hypothesized that the anisotropies of the crystal structure lead to locally high strain energies that are relieved by the growth of whiskers and hillocks. This research studies hillock formations on large grain Sn-alloy films relative to the crystallographic orientations of the adjacent grains. Large grain films were produced by solidifying 96.5wt% Sn - 3wt% Ag - 0.5wt% Cu solder alloy on a Cu substrate. These surface defects (hillocks) grew predominately at grain boundaries during thermal cycling. The formation of the surface defects between two grains created a pseudo-bi-crystal sample geometry, making it ideal for studying surface defects relative to the local crystallographic orientations and the grains' corresponding anisotropic properties. The crystallographic orientations of the grains were studied with Electron Backscatter Diffraction (EBSD) and Laue micro-diffraction at the Lawrence Berkeley National Laboratory Advanced Light Source. Local orientation studies of the surface defects and the surrounding grains indicated that the surface defects nucleated and grew with low dislocation densities. In addition, the linear surface defect densities along the grain boundaries were measured and observed to change as a function of orientation. The change in linear defect density with respect to orientation was due, in part, to the anisotropy of the coefficient of thermal expansion of β-Sn. In addition, it was important to account for elastic anisotropies. The elastic stresses, strains, and strain energy densities of the microstructures were determined with Object Oriented Finite element analysis. The simulations indicated that during thermal cycling the local stresses exceeded the yield strength. As a result, the highest linear defect densities did not occur at orientations

  18. The peculiarities of the crystallographics modification of a tissues from corpse during putrefactive corpse transformation

    Directory of Open Access Journals (Sweden)

    Fedorova Е.А.

    2013-12-01

    Full Text Available Background. The crystallographic method was used to study the extracts of organs and blood in forensic medicine is not developed yet. However, it is fairly easy to use and does not require additional special equipment, so there is quite promising. Objective. The aim of research are became basis of possibility and effectively to use by thezygraphy method for medico-legal definition of prescription of approach of death by tissue of a corpse during its putrefaction. Methods. Thezygraphy method is used a modification of crystallogramms during dynamics postmortem period for medico-legal definition of prescription of approach of death. Sectional material consisted of the corpses of people who died from violent and nonviolent death in the age range from 18 to 92 years. All the bodies after death were preserved in the same temperature conditions. The tissues from various internal organs: brain, heart, lungs, kidneys, liver, spleen and blood from 30 cadavers were the object of sectional study. There for 939 biological objects were investigated. Results. The article deals with generalization the crystallography (thezigraphy observation of crystallogramms from different tissues extract and blood depending on the different cause of violent and nonviolent death. The main purpose is to identify common crystallogramms features of the extracts of internal organs taken during putrefactive corpse transformation of people who died from various kinds of death. It has been proved that: 1.The typical сrystallogramms were formed from various tissue extracts: blood, brain, heart, lungs, liver, kidneys, spleen in first day after of approach of death, depending on the cause of deaths. 2. In the dynamics of postmortem period and putrefactive transformation of the corpses (first week the dynamic changes occur in crystallographic patterns obtained from extracts of the internal organs, and they can be used to establish the approach of death. Conclusion. The thezygraphy

  19. Novel FIR Inversion with Only FIRS

    CERN Document Server

    Chalmers, G

    2005-01-01

    The inversion of an FIR data sampling is usually stated to be possible with the use of a potentially unstable IIR, and in particular circumstances. It is possible to accomplish the same inversion with the doubling of an FIR sampling and with only FIRs for the sampling and the inversion. This note presents the configuration, which appently is not in the literature, for perfect signal reconstruction.

  20. Chromatid Painting for Chromosomal Inversion Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose the continued development of a novel approach to the detection of chromosomal inversions. Transmissible chromosome aberrations (translocations and...

  1. Bayesian approach to inverse statistical mechanics.

    Science.gov (United States)

    Habeck, Michael

    2014-05-01

    Inverse statistical mechanics aims to determine particle interactions from ensemble properties. This article looks at this inverse problem from a Bayesian perspective and discusses several statistical estimators to solve it. In addition, a sequential Monte Carlo algorithm is proposed that draws the interaction parameters from their posterior probability distribution. The posterior probability involves an intractable partition function that is estimated along with the interactions. The method is illustrated for inverse problems of varying complexity, including the estimation of a temperature, the inverse Ising problem, maximum entropy fitting, and the reconstruction of molecular interaction potentials.

  2. The structure of (L)*-inverse semigroups

    Institute of Scientific and Technical Information of China (English)

    REN Xueming; SHUM Karping

    2006-01-01

    The concepts of (L)*-inverse semigroups and left wreath products of semigroups are introduced. It is shown that the (L)*-inverse semigroup can be described as the left wreath product of a type A semigroup Γ and a left regular band B together with a mapping which maps the semigroup Γ into the endomorphism semigroup End(B). This result generalizes the structure theorem of Yamada for the left inverse semigroups in the class of regular semigroups.We shall also provide a constructed example for the (L)*-inverse semigroups by using the left wreath products.

  3. Analysis of nonlinear channel friction inverse problem

    Institute of Scientific and Technical Information of China (English)

    CHENG Weiping; LIU Guohua

    2007-01-01

    Based on the Backus-Gilbert inverse theory, the singular value decomposition (SVD) for general inverse matrices and the optimization algorithm are used to solve the channel friction inverse problem. The resolution and covari- ance friction inverse model in matrix form is developed to examine the reliability of solutions. Theoretical analyses demonstrate that the convergence rate of the general Newton optimization algorithm is in the second-order. The Wiggins method is also incorporated into the algorithm. Using the method, noise can be suppressed effectively, and the results are close to accurate solutions with proper control parameters. Also, the numerical stability can be improved.

  4. Inverse Kinematics of a Serial Robot

    Directory of Open Access Journals (Sweden)

    Amici Cinzia

    2016-01-01

    Full Text Available This work describes a technique to treat the inverse kinematics of a serial manipulator. The inverse kinematics is obtained through the numerical inversion of the Jacobian matrix, that represents the equation of motion of the manipulator. The inversion is affected by numerical errors and, in different conditions, due to the numerical nature of the solver, it does not converge to a reasonable solution. Thus a soft computing approach is adopted to mix different traditional methods to obtain an increment of algorithmic convergence.

  5. Measurement of Eccentricity of the Centre of Mass from the Geometric Centre of a Sphere

    Institute of Scientific and Technical Information of China (English)

    郭俊起; 胡忠坤; 顾邦明; 罗俊

    2004-01-01

    The eccentricity of the centre of mass from the geometric centre of a spherical attracting mass in determining the Newtonian gravitational constant G is tested by means of an electronic balance. The experimental result shows that the eccentricity of the sample is about 0.31 μm with uncertainty of 0.05 μm. Two density distribution models are discussed to estimate the uncertainty to G by the eccentricities of the attracting masses.

  6. HISTORIC CENTRE(S OF BARCELONA: PRACTICAL AND SYMBOLIC ELEMENTS IN TRADITIONAL URBAN SPACE

    Directory of Open Access Journals (Sweden)

    Verónica Martínez Robles

    2007-09-01

    The model of compact city that Barcelona aims, has required the renewal of its historical areas, and in order to improve their level of centrality, taking into account, that in addition of its historical centre “Ciutat Vella”, Barcelona contains diverse traditional neighborhoods each of them having their own historical centre. The difference centre‐periphery should also be perceived among these other historical centers. Integration should not be confused with standardization, neither differentiation with segregation.

  7. Effect of organizational features on patient satisfaction with care in Italian multiple sclerosis centres.

    Science.gov (United States)

    Mattarozzi, K; Baldin, E; Zenesini, C; Solari, A; Amato, M P; Leone, M; Mancardi, G; Martinelli, V; Savettieri, G; Solaro, C; Tola, M R; D'Alessandro, R

    2017-04-01

    Receiving clear, complete and up-to-date information and having a satisfying relationship with the health professional (HP) are of primary importance for MS patients. Healthcare organization plays a key role in promoting an effective relationship and communication between patients and HPs. The present study aims to explore which care organization and service characteristics provided by Italian MS centres best predict patients' satisfaction with healthcare. Eighty-one centres and 707 patients (502 women, mean age 40.5 years, SD 10.2; mean education 12.2 years, SD 3.6; time since diagnosis 5.9 years, SD 1.5) were included in the analysis. The care organization and service provided by each centre were evaluated in comparison with the National Institute for Health and Care Excellence (NICE) guidelines on management of MS. Patients' satisfaction with care was measured using the patient self-assessed questionnaire 'Comunicazione medico-paziente nella Sclerosi Multipla, revised' section 2 (COSM-R section 2). The clinical characteristics of patients significantly affected their satisfaction. A multivariate regression model showed that higher patients' satisfaction (COSM-R score) was inversely associated with hospital size (number of patients under care) (β = -0.21, 95% confidence interval -0.35; -0.07) and directly associated with psychological interventions (β = 2.44, 95% confidence interval 0.29; 4.59). Multiple sclerosis patients from larger hospitals are less satisfied with the information received and the relationship with HPs. Building an individualized relationship between patients and HPs and tailoring the communication of information improve patients' satisfaction. Such a goal is probably less likely to be accomplished in larger centres with many incoming patients. Moreover, when the centres also provide structured psychological interventions, the patients are more satisfied. © 2017 EAN.

  8. Global Monthly CO2 Flux Inversion Based on Results of Terrestrial Ecosystem Modeling

    Science.gov (United States)

    Deng, F.; Chen, J.; Peters, W.; Krol, M.

    2008-12-01

    Most of our understanding of the sources and sinks of atmospheric CO2 has come from inverse studies of atmospheric CO2 concentration measurements. However, the number of currently available observation stations and our ability to simulate the diurnal planetary boundary layer evolution over continental regions essentially limit the number of regions that can be reliably inverted globally, especially over continental areas. In order to overcome these restrictions, a nested inverse modeling system was developed based on the Bayesian principle for estimating carbon fluxes of 30 regions in North America and 20 regions for the rest of the globe. Inverse modeling was conducted in monthly steps using CO2 concentration measurements of 5 years (2000 - 2005) with the following two models: (a) An atmospheric transport model (TM5) is used to generate the transport matrix where the diurnal variation n of atmospheric CO2 concentration is considered to enhance the use of the afternoon-hour average CO2 concentration measurements over the continental sites. (b) A process-based terrestrial ecosystem model (BEPS) is used to produce hourly step carbon fluxes, which could minimize the limitation due to our inability to solve the inverse problem in a high resolution, as the background of our inversion. We will present our recent results achieved through a combination of the bottom-up modeling with BEPS and the top-down modeling based on TM5 driven by offline meteorological fields generated by the European Centre for Medium Range Weather Forecast (ECMFW).

  9. Purification, identification and preliminary crystallographic studies of Pru du amandin, an allergenic protein from Prunus dulcis

    Energy Technology Data Exchange (ETDEWEB)

    Gaur, Vineet; Sethi, Dhruv K.; Salunke, Dinakar M., E-mail: dinakar@nii.res.in [National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110 067 (India)

    2008-01-01

    The purification, identification, crystallization and preliminary crystallographic studies of an allergy-related protein, Pru du amandin, from P. dulcis nuts are reported. Food allergies appear to be one of the foremost causes of hypersensitivity reactions. Nut allergies account for most food allergies and are often permanent. The 360 kDa hexameric protein Pru du amandin, a known allergen, was purified from almonds (Prunus dulcis) by ammonium sulfate fractionation and ion-exchange chromatography. The protein was identified by a BLAST homology search against the nonredundant sequence database. Pru du amandin belongs to the 11S legumin family of seed storage proteins characterized by the presence of a cupin motif. Crystals were obtained by the hanging-drop vapour-diffusion method. The crystals belong to space group P4{sub 1} (or P4{sub 3}), with unit-cell parameters a = b = 150.7, c = 164.9 Å.

  10. Paramagnetic and crystallographic effects of low temperature ashing on human bone and tooth enamel.

    Science.gov (United States)

    Tochon-Danguy, H J; Very, J M; Geoffroy, M; Baud, C A

    1978-02-28

    Low temperature ashing by excited gas (LTA) causes crystallographic and paramagnetic alterations of the human bone and tooth enamel mineral. On the one hand, LTA induces variations of the alpha lattice parameter. These variations depend upon the nature of the gas used, but are little affected by its degree of excitation. Trapping of gas molecules in the crystal structure is demonstrated. On the other hand, LTA produces two preponderant paramagnetic centers in bone and enamel samples at 20 degrees C. Their inorganic origin clearly indicated. One of the two radicals has been identified as O3- (g1 = 2.002, g2 = 2.010, g3 = 2.016) and the other as (CO3-3 (parallel = 1.996, g = perpendicular 2.003). Variations of the alpha lattice parameter and trapping of paramagnetic gas species do not seem to be directly related.

  11. Radiation of high-energy electrons near crystallographic axes and planes of a diamond crystal

    Energy Technology Data Exchange (ETDEWEB)

    Avakyan, R.O.; Avakyan, E.O.; Avetisyan, A.E.

    1986-05-01

    The paper is devoted to the experimental study of high-energy electrons interaction with diamond crystals of different thicknesses at small incident angles with respect to crystallographic axes and planes. The effect of the so-called channeling phenomenon on the process of electron radiation in a crystal is studied. Results of the measurements of 4.5. GeV electrons radiation spectra at incident angles approximately O are given. For comparison, we have also presented the spectrum of the radiation on an amorphous target /sup 12/C of similar thickness. Results indicate that the low-energy part of spectra greatly surpass the amorphous spectrum with a pronounced peak structure, with peak widths being noticeably wider in the case of axial channeling than in the planar case. Spectra are measured by a No.I(Tl) total absorption detector. The experiment is performed on the Yerevan electron synchrotron beam with small angular divergence.

  12. Platinum Group Thiophenoxyimine Complexes: Syntheses,Crystallographic and Computational Studies of Structural Properties

    Energy Technology Data Exchange (ETDEWEB)

    Krinsky, Jamin L.; Arnold, John; Bergman, Robert G.

    2006-10-03

    Monomeric thiosalicylaldiminate complexes of rhodium(I) and iridium(I) were prepared by ligand transfer from the homoleptic zinc(II) species. In the presence of strongly donating ligands, the iridium complexes undergo insertion of the metal into the imine carbon-hydrogen bond. Thiophenoxyketimines were prepared by non-templated reaction of o-mercaptoacetophenone with anilines, and were complexed with rhodium(I), iridium(I), nickel(II) and platinum(II). X-ray crystallographic studies showed that while the thiosalicylaldiminate complexes display planar ligand conformations, those of the thiophenoxyketiminates are strongly distorted. Results of a computational study were consistent with a steric-strain interpretation of the difference in preferred ligand geometries.

  13. Processing and crystallographic structure of non-equilibrium Si-doped HfO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Dong; Fancher, Chris M.; Esteves, Giovanni; Jones, Jacob L., E-mail: jacobjones@ncsu.edu [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Zhao, Lili [School of Information Science and Technology, Northwest University, Xi' an 710127 (China)

    2015-06-28

    Si-doped HfO{sub 2} was confirmed to exist as a non-equilibrium state. The crystallographic structures of Si-doped HfO{sub 2} were studied using high-resolution synchrotron X-ray diffraction and the Rietveld refinement method. Incorporation of Si into HfO{sub 2} and diffusion of Si out of (Hf,Si)O{sub 2} were determined as a function of calcination temperature. Higher thermal energy input at elevated calcination temperatures resulted in the formation of HfSiO{sub 4}, which is the expected major secondary phase in Si-doped HfO{sub 2}. The effect of SiO{sub 2} particle size (nano- and micron-sized) on the formation of Si-doped HfO{sub 2} was also determined. Nano-crystalline SiO{sub 2} was found to incorporate into HfO{sub 2} more readily.

  14. Quantification of thin film crystallographic orientation using X-ray diffraction with an area detector.

    Science.gov (United States)

    Baker, Jessy L; Jimison, Leslie H; Mannsfeld, Stefan; Volkman, Steven; Yin, Shong; Subramanian, Vivek; Salleo, Alberto; Alivisatos, A Paul; Toney, Michael F

    2010-06-01

    As thin films become increasingly popular (for solar cells, LEDs, microelectronics, batteries), quantitative morphological and crystallographic information is needed to predict and optimize the film's electrical, optical, and mechanical properties. This quantification can be obtained quickly and easily with X-ray diffraction using an area detector in two sample geometries. In this paper, we describe a methodology for constructing complete pole figures for thin films with fiber texture (isotropic in-plane orientation). We demonstrate this technique on semicrystalline polymer films, self-assembled nanoparticle semiconductor films, and randomly packed metallic nanoparticle films. This method can be immediately implemented to help understand the relationship between film processing and microstructure, enabling the development of better and less expensive electronic and optoelectronic devices.

  15. Ge/SrTiO{sub 3}(001): Correlation between interface chemistry and crystallographic orientation

    Energy Technology Data Exchange (ETDEWEB)

    Gobaut, B.; Penuelas, J.; Grenet, G.; Ferrah, D.; Benamrouche, A.; Chettaoui, A.; Robach, Y.; Botella, C.; Saint-Girons, G. [Universite de Lyon, Institut des Nanotechnologies de Lyon, Ecole Centrale de Lyon, 36 avenue Guy de Collongue, 69134 Ecully (France); El Kazzi, M.; Silly, M. G.; Sirotti, F. [Synchrotron SOLEIL (TEMPO beamline), l' Orme des Merisiers, Saint-Aubin, 91192 Gif-sur-Yvette (France)

    2012-11-01

    In this work, the desorption of a submonolayer deposit of Ge on SrTiO{sub 3}(001) is studied by reflection high energy electron diffraction. The results are compared to those of a previous experiment done using soft x-ray photoelectron spectroscopy. Combining these techniques allows for correlating interface chemistry and crystal orientation, and for bringing clarifying elements concerning the competition between (111) and (001) crystal orientation typical for the semiconductor/perovskite epitaxial systems. Despite poor interface matching, (111)-oriented islands are stabilized at the expense of (001)-oriented islands due to the relatively low energy of their free facets. Such 'surface energy driven' crystallographic orientation of the deposit is enhanced by the low adhesion energy characteristic of the Ge/SrTiO{sub 3} system.

  16. Dianthraceno[a,e]pentalenes: Synthesis, crystallographic structures and applications in organic field-effect transistors

    KAUST Repository

    Dai, Gaole

    2015-01-01

    Two soluble and stable dianthraceno[a,e]pentalenes with two (DAP1) and six (DAP2) phenyl substituents were synthesized. Both compounds possess a small energy band gap and show amphoteric redox behaviour due to intramolecular donor-accepter interactions. X-ray crystallographic analysis revealed that DAP2 has a closely packed structure with multi-dimensional [C-H⋯π] interactions although there are no π-π interactions between the dianthraceno[a,e]pentalene cores. As a result, solution-processed field effect transistors based on DAP2 exhibited an average hole mobility of 0.65 cm2 V-1 s-1. Under similar conditions, DAP1 showed an average field effect hole mobility of 0.001 cm2 V-1 s-1. This journal is

  17. Preliminary crystallographic data for the thiamin diphosphate-dependent enzyme pyruvate decarboxylase from brewers' yeast.

    Science.gov (United States)

    Dyda, F; Furey, W; Swaminathan, S; Sax, M; Farrenkopf, B; Jordan, F

    1990-10-15

    Single crystals of the thiamin diphosphate (the vitamin B1 coenzyme)-dependent enzyme pyruvate decarboxylase (EC 4.1.1.1) from brewers' yeast have been grown using polyethylene glycol as a precipitating agent. Crystals of the homotetrameric version alpha 4 of the holoenzyme are triclinic, space group P1, with cell constants a = 81.0, b = 82.4, c = 116.6 A, alpha = 69.5 beta = 72.6, gamma = 62.4 degrees. The crystals are reasonably stable in a rotating anode x-ray beam and diffract to at least 2.5 A resolution. The Vm value of 2.55 A/dalton is consistent with a unit cell containing four subunits with mass of approximately 60 kDa each. Rotation function results with native data indicate strong non-crystallographic 222 symmetry relating the four identical subunits, thus density averaging methods are likely to play a role in the structure determination.

  18. Crystallographic analysis of CVD films using x-ray polychromatic radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lavelle, B. [CNRS, Toulouse (France). Centre d`Elaboration de Materiaux et d`Etudes Structurales; Brissonneau, L.; Baggot, E.; Vahlas, C. [INPT-CNRS, Toulouse (France). Lab. Materiaux et Interfaces

    1998-12-31

    The Energy Dispersive X-ray Diffractometry (EDXD) technique was tested for in-situ crystallographic characterization of nickel films processed by chemical vapor deposition (CVD). The diffracted beam at low Bragg angle was analyzed in energy by a solid state detector. A nickel reference sample was used to face the problems of EDXD background signal and uncertainty of sample location. The relative accuracy on lattice parameters measurements is 1.5.10{sup {minus}3}, to be compared to 0.5.10{sup {minus}3} for classical (monochromatic) X-ray diffraction. Texture measurements yields results in agreement with those obtained form recent texture goniometer. Finally, an estimation of the thickness was obtained from the intensity of nickel fluorescence peak. In view of the obtained results, EDXD appears to be a promising technique for in-situ studies. Although less powerful compared to the synchrotron facility, it is more flexible and can be applied at lower cost.

  19. Lytic polysaccharide monooxygenases: a crystallographer's view on a new class of biomass-degrading enzymes

    Directory of Open Access Journals (Sweden)

    Kristian E. H. Frandsen

    2016-11-01

    Full Text Available Lytic polysaccharide monooxygenases (LPMOs are a new class of microbial copper enzymes involved in the degradation of recalcitrant polysaccharides. They have only been discovered and characterized in the last 5–10 years and have stimulated strong interest both in biotechnology and in bioinorganic chemistry. In biotechnology, the hope is that these enzymes will finally help to make enzymatic biomass conversion, especially of lignocellulosic plant waste, economically attractive. Here, the role of LPMOs is likely to be in attacking bonds that are not accessible to other enzymes. LPMOs have attracted enormous interest since their discovery. The emphasis in this review is on the past and present contribution of crystallographic studies as a guide to functional understanding, with a final look towards the future.

  20. Preparation, crystallization and preliminary crystallographic analysis of old yellow enzyme from Trypanosoma cruzi

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, Shigeru [Maruwa Foods Co. Ltd, Tsutsui-cho 170-1, Yamatokoriyama, Nara 639-1123 (Japan); Tokuoka, Keiji [Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamada-Oka, Suita, Osaka 565-0871 (Japan); Uchiyama, Nahoko [Department of Molecular Behavioral Biology, Osaka Bioscience Institute, Osaka 565-0874 (Japan); Okamoto, Naoki; Okano, Yousuke; Matsumura, Hiroyoshi [Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamada-Oka, Suita, Osaka 565-0871 (Japan); Inaka, Koji [Maruwa Foods Co. Ltd, Tsutsui-cho 170-1, Yamatokoriyama, Nara 639-1123 (Japan); Urade, Yoshihiro [Department of Molecular Behavioral Biology, Osaka Bioscience Institute, Osaka 565-0874 (Japan); Inoue, Tsuyoshi, E-mail: inouet@chem.eng.osaka-u.ac.jp [Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamada-Oka, Suita, Osaka 565-0871 (Japan); Maruwa Foods Co. Ltd, Tsutsui-cho 170-1, Yamatokoriyama, Nara 639-1123 (Japan)

    2007-10-01

    Old yellow enzyme from Trypanosoma cruzi, has been crystallized using the hanging-drop vapour-diffusion method. Old yellow enzyme (OYE) is an NADPH oxidoreductase that contains a flavin mononucleotide as a prosthetic group. The OYE from Trypanosoma cruzi, which produces prostaglandin F{sub 2α}, a potent mediator of various physiological and pathological processes, from prostaglandin H2. The protein was recombinantly expressed and purified from Escherichia coli and was crystallized using the hanging-drop vapour-diffusion method. The crystal belongs to the monoclinic space group P2{sub 1}, with unit-cell parameters a = 56.3, b = 78.8, c = 78.8 Å, β = 93.4° and two molecules per asymmetric unit. The crystals were suitable for X-ray crystallographic studies and diffracted to 1.70 Å resolution. A Patterson search method is in progress using the structure of OYE from Pseudomonas putida as a starting model.

  1. Effects of unstratified and centre-stratified randomization in multi-centre clinical trials.

    Science.gov (United States)

    Anisimov, Vladimir V

    2011-01-01

    This paper deals with the analysis of randomization effects in multi-centre clinical trials. The two randomization schemes most often used in clinical trials are considered: unstratified and centre-stratified block-permuted randomization. The prediction of the number of patients randomized to different treatment arms in different regions during the recruitment period accounting for the stochastic nature of the recruitment and effects of multiple centres is investigated. A new analytic approach using a Poisson-gamma patient recruitment model (patients arrive at different centres according to Poisson processes with rates sampled from a gamma distributed population) and its further extensions is proposed. Closed-form expressions for corresponding distributions of the predicted number of the patients randomized in different regions are derived. In the case of two treatments, the properties of the total imbalance in the number of patients on treatment arms caused by using centre-stratified randomization are investigated and for a large number of centres a normal approximation of imbalance is proved. The impact of imbalance on the power of the study is considered. It is shown that the loss of statistical power is practically negligible and can be compensated by a minor increase in sample size. The influence of patient dropout is also investigated. The impact of randomization on predicted drug supply overage is discussed.

  2. Crystallization and preliminary crystallographic analysis of l-asparaginase from Erwinia carotovora

    Energy Technology Data Exchange (ETDEWEB)

    Wikman, Linnea E. K. [Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku 20521 (Finland); Krasotkina, Julya; Kuchumova, Anastasia; Sokolov, Nikolay N. [Institute for Biomedical Chemistry, Russian Academy of Medical Sciences, 559-B, 10 Pogodinskay St, Moscow 119121 (Russian Federation); Papageorgiou, Anastassios C., E-mail: tassos.papageorgiou@btk.fi [Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku 20521 (Finland)

    2005-04-01

    Er. carotovoral-asparaginase, a potential antileukaemic agent, has been crystallized. Crystals diffract to 2.6 Å using a rotating-anode source and belong to space group P2{sub 1}, with unit-cell parameters a = 78.0, b = 112.3, c = 78.7 Å, β = 101.9° and a homotetramer in the crystallographic asymmetric unit. Bacterial l-asparaginases have been used as therapeutic agents in the treatment of acute childhood lymphoblastic leukaemia for over 30 y. However, their use is limited owing to the glutaminase activity of the administered enzymes, which results in serious side effects. In contrast, l-asparaginase from Erwinia carotovora exhibits low glutaminase activity at physiological concentrations of l-asparagine and l-glutamine in the blood. Recombinant Er. carotovoral-asparaginase was crystallized in the presence of l-glutamate by the hanging-drop vapour-diffusion method using 10 mg ml{sup −1} purified enzyme, 16–18%(w/v) PEG 3350 and 0.2 M NaF. X-ray diffraction data were collected to 2.6 Å at 293 K using an in-house rotating-anode generator. The crystals belong to the monoclinic P2{sub 1} space group, with unit-cell parameters a = 78.0, b = 112.3, c = 78.7 Å, β = 101.9° and a homotetramer in the crystallographic asymmetric unit. A molecular-replacement solution has been found and refinement is currently in progress. The crystal structure may provide leads towards protein-engineering efforts aimed at safer asparaginase administration in leukaemia treatment.

  3. Achieving competences in patient-centred care

    DEFF Research Database (Denmark)

    Lomborg, Kirsten; Nielsen, Else Skånning; Jensen, Annesofie Lunde

    2011-01-01

    Aim: To document the efficacy of a training programme in patient-centred care in which the nursing staff was trained to involve chronic obstructive pulmonary patients in assisted personal body care (APBC). The objectives were to describe the programme and uncover the outcomes. Background: Chronic...... obstructive pulmonary patients suffer from breathlessness and may need comprehensive assistance with personal body care. The patients’ wellbeing may be improved and their integrity safeguarded if nurses are able to involve the patients in accordance with their illness conditions and personal preferences....... The training was time-consuming. Conclusion: A comprehensive training programme can improve nursing competences to action patient-centred and involve severely ill respiratory patients in APBC. Further studies are needed to investigate the efficacy from the patients’ perspective. Relevance to clinical practice...

  4. JOB CENTRE FOR DOMESTIC STAFF IN SWITZERLAND

    CERN Multimedia

    Relations with the Host States Service; http://www.cern.ch/relations/

    2001-01-01

    The Permanent mission of Switzerland to the International Organisations in Geneva has informed CERN that the Geneva Welcome Centre has set up an employment registration desk for the domestic staff of international civil servants. The aim of this pilot project is, on the one hand, to help international civil servants find domestic staff and, on the other hand, to help domestic staff holding an 'F'-type carte de légitimation find employment within 30 days after the expiry of a contract. For more information, please contact the Geneva Welcome Centre, La Pastorale, 106, route de Ferney, Case postale 103, 1211 Genève 20, tel. (+41.22) 918 02 70, fax (+41.22) 918 02 79), http://geneva-international.org/Welcome.E.html.

  5. Institutional profile: the London Centre for Nanotechnology.

    Science.gov (United States)

    Weston, David; Bontoux, Thierry

    2009-12-01

    Located in the London neighborhoods of Bloomsbury and South Kensington, the London Centre for Nanotechnology is a UK-based multidisciplinary research center that operates at the forefront of science and technology. It is a joint venture between two of the world's leading institutions, UCL and Imperial College London, uniting their strong capabilities in the disciplines that underpin nanotechnology: engineering, the physical sciences and biomedicine. The London Centre for Nanotechnology has a unique operating model that accesses and focuses the combined skills of the Departments of Chemistry, Physics, Materials, Medicine, Electrical and Electronic Engineering, Mechanical Engineering, Chemical Engineering, Biochemical Engineering and Earth Sciences across the two universities. It aims to provide the nanoscience and nanotechnology required to solve major problems in healthcare, information processing, energy and the environment.

  6. Emergency Centre Organization and Automated Triage System

    CERN Document Server

    Golding, Dan; Marwala, Tshilidzi

    2008-01-01

    The excessive rate of patients arriving at accident and emergency centres is a major problem facing South African hospitals. Patients are prioritized for medical care through a triage process. Manual systems allow for inconsistency and error. This paper proposes a novel system to automate accident and emergency centre triage and uses this triage score along with an artificial intelligence estimate of patient-doctor time to optimize the queue order. A fuzzy inference system is employed to triage patients and a similar system estimates the time but adapts continuously through fuzzy Q-learning. The optimal queue order is found using a novel procedure based on genetic algorithms. These components are integrated in a simple graphical user interface. Live tests could not be performed but simulations reveal that the average waiting time can be reduced by 48 minutes and priority is given to urgent patients

  7. Danish Polymer Centre annual report 2001

    DEFF Research Database (Denmark)

    Hassager, O.; Hvilsted, S.; Mortensen, Kell

    The centre is a collaboration between the Risø National Laboratory and the Technical University of Denmark (DTU). At the DTU the Department of Chemical Engineering and the Department of Manufacturing Engineering and Management participate in the centre.From 2001 the Polymer Department at Risø...... campus in Lyngby as shown in the pictures on this page. In addition to well equipped laboratories at Risø which will be expanded in 2002 and 2003, thesefacilities provide a common ground for polymer chemists, polymer physicists, chemical engineers and mechanical engineers from the two institutions...... coordinates the activities at Risø From the outset it was considered important with common laboratories to obtain the full effect of the collaboration between the two departments at the DTU and Risø NationalLaboratory. In 2001 new laboratories for polymer research and education were established at the DTU...

  8. Danish Polymer Centre annual report 2001

    DEFF Research Database (Denmark)

    Hassager, O.; Hvilsted, S.; Mortensen, Kell

    The centre is a collaboration between the Risø National Laboratory and the Technical University of Denmark (DTU). At the DTU the Department of Chemical Engineering and the Department of Manufacturing Engineering and Management participate in the centre.From 2001 the Polymer Department at Risø coo....... The Annual Report for 2001 represents therefore the first report from a period in which the new facilitieshave been utilized to full advantage....... coordinates the activities at Risø From the outset it was considered important with common laboratories to obtain the full effect of the collaboration between the two departments at the DTU and Risø NationalLaboratory. In 2001 new laboratories for polymer research and education were established at the DTU...

  9. [The development process of colon cancer centres].

    Science.gov (United States)

    Sahm, M; Wesselmann, S; Kube, R; Schöffel, N; Pross, M; Lippert, H; Kahl, S

    2013-02-01

    Colon carcinomas are the most common malignant tumours in the Western world. Important findings about the overall quality of medical care have been reported in multi-centre observational studies. A quality enhancement of therapeutic care can be achieved by an additional increase in diagnostic and therapeutic measures in the interdisciplinary setting. The development of colon cancer centres improves the chance to objectively observe the results of medical care induced by the development of an interdisciplinary and cross-sectoral unit that includes a comprehensive medical care for patients. The implementation of the current medical findings based on evidence in clinical routine, the inspection of the usage of guidelines by external specialists as part of an audit and the continuous correction of analysed deficits in the course of treatment guarantee a continuous improvement of service.

  10. It's all change at the Computer Centre

    CERN Multimedia

    Laëtitia Pedroso

    2011-01-01

    The IT and EN Departments are modernising the infrastructure of the Computer Centre to improve the conditions in which the equipment has to operate and to increase capacity. The construction work has already begun and is due to be completed in October 2012.   Every year CERN experiences around ten power cuts lasting from less than a second to several hours. In most cases the two protection systems - the UPS* and the diesel generators – are able to ensure that the operation of the Computer Centre is not affected. As Vincent Doré, the project leader for the IT Department, and Paul Pepinster, the EN Department's technical coordinator in charge of modernising the infrastructure, explains: "Building 513 has two types of computing facilities – the "non-critical" ones, such as the servers for "off-line" computing, which have UPS systems ensuring that they can operate for 10 minutes after a power cut, and the "critical&...

  11. The structure of *-inverse semigroups

    Institute of Scientific and Technical Information of China (English)

    REN; Xueming

    2006-01-01

    [1]Hall T E.Orthodox semigroups.Pacific J Math,1971,39:677-686[2]Howie J M.An Introduction to Semigroup Theory.Now York:Academic Press,1976[3]Fountain J B.Abundant semigroups.Proc Lond Math Soc,1982,44 (3):103-129[4]El-Qallali A,Fountain J B.Idempotent-connected abundant semigroups.Proc Roy Soc Edinburgh,1981,Sec.A:79-90[5]El-Qallali A,Fountain J B.Quasi-adequate semigroups.Proc Roy Soc Edinburgh,1981,Sec.A:91-99[6]Fountain J B.Adequate semigroups.Proc Edinburgh Math Soc,1979,22:113-125[7]Guo X J.Abundant C-lpp proper semigroups.Southeast Asian Bull Math,2000,24 (1):41-50[8]Guo X J,Shum K P,Guo Y Q.Perfect rpp semigroups.Communications in Algebra,2001,29(6):2447-2459[9]Ren X M,Shum K P.Structure theorems for right pp-semigroups with left central idempotents.Discussions Math General Algebra and Applications,2000,20:63-75[10]Ren X M,Shum K P.The structure of superabundant semigroups.Sci China Ser A-Math,2004,47(5):756-771[11]Shum K P,Ren X M.Abundant semigroups with left central idempotents.Pure Math Appl,1999,10(1):109-113[12]Armstrong S.The structure of type A semigroups.Semigroup Forum,1984,29:319-336[13]Lawson M V.The structure of type A semigroups.Quart J Math Oxford,1986,37(2):279-298[14]Bailes G L.Right inverse semigroups.J Algebra,1973,26:492-507[15]Venkatesan P S.Right (left) inverse semigroups.J Algebra,1974,31:209-217[16]Yamada M.Orthodox semigroups whose idempotents satisfy a certain identity.Semigroup Forum,1973,6:113-128[17]Preston G B.Semiproducts of semigroups.Proc Roy Soc Edinburgh,1986,102A:91-102[18]Preston G B:Products of semigroups.In:Shum K P,Yuen P C,eds.Proc.of the conference"Ordered structures and algebra of computer languages",1991 (Hong Kong).Singapore:World Scientific Inc,1993.161-169[19]Lawson M V.The natural partial order on an abundant semigroup.Proc Edinburgh Math Soc,1987,30:169-186[20]El-Qallali A.(L)*-unipotent semigroups.J Pure and Applied Algebra,1989,62:19-23

  12. Training science centre Explainers. The Techniquest experience

    Directory of Open Access Journals (Sweden)

    Colin Johnson

    2005-12-01

    Full Text Available Techniquest was established in 1986, and in 1995 moved to its current premises at Cardiff Bay, South Wales. This was the first purpose-built science centre in the UK. It receives around 200,000 visitors every year to its exhibition, and to its programmes for schools and public audiences in the theatre, laboratory, discovery room and planetarium. The author joined the Techniquest project in 1985, became a staff member in 1990 and was the Chief Executive from 1997 until his retirement in 2004. Techniquest has three “out-stations” in Wales, and is responsible for the supply and maintenance of exhibits to the Look Out Discovery Centre in Bracknell, England. There is a Techniquest gallery at the Lisbon Pavilhão do Conhecimento - Ciência Viva, and a traveling exhibition, SciQuest, in South Africa which was also supplied by Techniquest. All these centres rely on the effective intervention of “Explainers” (at Techniquest we call them “Helpers” to provide the best possible experience for visitors. At its most demanding, the tasks of an Explainer are varied and intensive, yet there may be times when the duties are mundane or even dull. When you rely on people to act as both hosts and housekeepers, to provide both support and stimulus, and to be both welcoming and watchful, you are asking a great deal. This article raises some of the issues concerned with the recruitment and retention of Explainers, their training and management, and the way in which their role is recognized and valued by the science centre as a whole.

  13. Enhancing Safety at Airline Operations Control Centre

    Directory of Open Access Journals (Sweden)

    Lukáš Řasa

    2015-04-01

    Full Text Available In recent years a new term of Safety Management System (SMS has been introduced into aviation legislation. This system is being adopted by airline operators. One of the groundbased actors of everyday operations is Operations Control Centre (OCC. The goal of this article has been to identify and assess risks and dangers which occur at OCC and create a template for OCC implementation into SMS.

  14. User-Centred Design Using Gamestorming.

    Science.gov (United States)

    Currie, Leanne

    2016-01-01

    User-centered design (UX) is becoming a standard in software engineering and has tremendous potential in healthcare. The purpose of this tutorial will be to demonstrate and provide participants with practice in user-centred design methods that involve 'Gamestorming', a form of brainstorming where 'the rules of life are temporarily suspended'. Participants will learn and apply gamestorming methods including persona development via empathy mapping and methods to translate artefacts derived from participatory design sessions into functional and design requirements.

  15. CMS Centres Worldwide - a New Collaborative Infrastructure

    CERN Document Server

    Taylor, Lucas

    2011-01-01

    Webcasts, and generic Web tools such as CMS-TV for broadcasting live monitoring and outreach information. Being Web-based and experiment-independent, these systems could easily be extended to other organizations. We describe the experiences of using CMS Centres Worldwide in the CMS data-taking operations as well as for major media events with several hundred TV channels, radio stations, and many more press journalists simultaneously around the world.

  16. Birth of a science centre. Italian phenomenology

    Directory of Open Access Journals (Sweden)

    Paola Rodari

    2006-06-01

    Full Text Available In May 2004 the Balì Museum, Planetarium and interactive science museum, was opened to the public in Italy: 35 hands-on exhibits designed according to the interactive tradition of the Exploratorium in San Francisco, an astronomic observatory for educational activities, a Planetarium with 70 places. With a total investment of about three million euros, about two thirds of which were spent on restructuring the splendid eighteenth-century villa in which it is housed, the undertaking may be considered a small one in comparison with other European science centres. Three million euros: perhaps enough to cover the cost of only the splendid circular access ramp to the brand-new Cosmocaixa in Barcelona, an investment of one hundred million euros. But the interesting aspect of the story of the Balì Museum (but also of other Italian stories, as we shall see lies in the fact that this lively and advanced science centre stands in the bucolic region of the Marches, next to a small town of only 800 inhabitants (Saltara, in the Province of Pesaro and Urbino, in a municipal territory that has a total of 5000. Whereas in Italy the projects for science centres comparable with the Catalan one, for example projects for Rome and Turin, never get off the ground, smaller ones are opening in small and medium-sized towns: why is this? And what does the unusual location of the centres entail for science communication in Italy? This Focus does not claim to tell the whole truth about Italian interactive museums, but it does offer some phenomenological cues to open a debate on the cultural, economic and political premises that favour their lives.

  17. Bismuth centred magnetic perovskite: A projected multiferroic

    Energy Technology Data Exchange (ETDEWEB)

    Kundu, Asish K., E-mail: asish.k@gmail.com [Discipline of Physics, Indian Institute of Information Technology, Design and Manufacturing, Dumna Airport Road, Jabalpur 482005 (India); Seikh, Md. Motin [Department of Chemistry, Visva-Bharati University, Santiniketan, West Bengal 731235 (India); Nautiyal, Pranjal [Discipline of Mechanical Engineering, Indian Institute of Information Technology, Design and Manufacturing, Dumna Airport Road, Jabalpur 482005 (India)

    2015-03-15

    In recent time substantial attention has been initiated to understand the physics behind multiferroism and to design new multiferroic materials. BiMnO{sub 3} and BiFeO{sub 3} are the well-studied Bi-centred multiferroic oxides. BiMnO{sub 3} is a ferromagnetic–ferroelectric (metastable) phase and require drastic conditions to synthesize. However, lanthanum substituted BiMnO{sub 3} phases stabilized at ambient pressure. It is thus of major importance to increase the number of ferromagnetic perovskites with Bi cations that could be designed under ambient conditions. In this article, we have presented an up to date report of investigations on Bi-centred magnetic perovskites, a prospective material for multiferroic application. Central focus is concentrated on La{sub 0.5}Bi{sub 0.5}MnO{sub 3} perovskite with various substitutions at different levels. A few of these perovskites are found to be of practical importance e.g. La{sub 0.5}Bi{sub 0.5}Mn{sub 0.67}Co{sub 0.33}O{sub 3} with high dielectric permittivity coupled with ferromagnetism. A comprehensive analysis of different physical functionalities and their interrelation for a wide range of compositions of these Bi-centred perovskites is presented. It has been found that the complex magnetic behaviour originates from mixed valence metal ions. The ferroelectricity is associated with the 6s{sup 2} lone pair of Bi{sup 3+} cations. The magnetic ground state influences the dielectric properties reflecting the multiferroism in a single material. - Highlights: • Multiferroics have attracted increasing attention due to their possible device applications. • Bismuth centred magnetic perovskite is one kind of such promising multiferroic materials. • Ferromagnetic Bi-perovskites, which are synthesized at ambient conditions, have been discussed.

  18. A new visitor centre for CMS

    CERN Multimedia

    2001-01-01

    At the inauguration of the new CMS visitor centre. The CMS experiment inaugurated a new visitor centre at its Cessy site on 14 June. This will allow the thousands of people who come to CERN each year to follow the construction of one the Laboratory's flagship experiments first-hand. CERN receives over 20,000 visitors each year. Until recently, many of them were taken on a guided tour of one of the LEP experiments. With the closure of LEP, however, trips underground are no longer possible, and the Visits' Service has put in place a number of other itineraries (Bulletin 46/2000). Since the CMS detector will be almost entirely constructed in a surface hall, it is now taking a big share of the limelight. The CMS visitor centre has been built on a platform overlooking CMS construction. It contains a set of clear descriptive posters describing the experiment, along with a video projection showing animations and movies about CMS construction. In the coming weeks, a display of CMS detector elements will be added, as...

  19. Upcoming opening of CERN's new Mobility Centre

    CERN Multimedia

    2016-01-01

    On 29 February, CERN’s brand new Mobility Centre opened in the Globe car park. The Centre has been created to cater to the transport needs of everyone at CERN, to simplify procedures and to centralise all the transport services on offer: the rental of CERN bikes and cars, the CERN car-sharing scheme and SIXT car rental.   From 29 February onwards, the Mobility Centre in the Globe car park will be the place to go for all your duty travel needs: rental of CERN cars (with or without the CERN logo), SIXT car rental, CERN bike rental, distribution of cards allowing the use of CERN’s self-service bike- and car-sharing schemes. That same day, the premises currently housing the Car Pool in Building 130 will become the CERN garage, responsible for: upkeep and repairs on CERN bikes, minor maintenance work on CERN vehicles (e.g. replacing windscreen wipers, bulbs and fuses, refilling windscreen washer fluid, pumping up tyres, etc.), arranging and following up the repair and maintenan...

  20. Bismuth centred magnetic perovskite: A projected multiferroic

    Science.gov (United States)

    Kundu, Asish K.; Seikh, Md. Motin; Nautiyal, Pranjal

    2015-03-01

    In recent time substantial attention has been initiated to understand the physics behind multiferroism and to design new multiferroic materials. BiMnO3 and BiFeO3 are the well-studied Bi-centred multiferroic oxides. BiMnO3 is a ferromagnetic-ferroelectric (metastable) phase and require drastic conditions to synthesize. However, lanthanum substituted BiMnO3 phases stabilized at ambient pressure. It is thus of major importance to increase the number of ferromagnetic perovskites with Bi cations that could be designed under ambient conditions. In this article, we have presented an up to date report of investigations on Bi-centred magnetic perovskites, a prospective material for multiferroic application. Central focus is concentrated on La0.5Bi0.5MnO3 perovskite with various substitutions at different levels. A few of these perovskites are found to be of practical importance e.g. La0.5Bi0.5Mn0.67Co0.33O3 with high dielectric permittivity coupled with ferromagnetism. A comprehensive analysis of different physical functionalities and their interrelation for a wide range of compositions of these Bi-centred perovskites is presented. It has been found that the complex magnetic behaviour originates from mixed valence metal ions. The ferroelectricity is associated with the 6s2 lone pair of Bi3+ cations. The magnetic ground state influences the dielectric properties reflecting the multiferroism in a single material.

  1. Anisotropic grain morphology, crystallographic texture and their implications for flux pinning mechanisms in MgB{sub 2} pellets, filaments and thin films

    Energy Technology Data Exchange (ETDEWEB)

    Song Xueyan [Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI (United States) and Applied Superconductivity Center, University of Wisconsin-Madison, Madison, WI (United States)]. E-mail: xsong@facstaff.wisc.edu; Babcock, S.E.; Eom, C.B.; Larbalestier, D.C. [Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI (United States); Applied Superconductivity Center, University of Wisconsin-Madison, Madison, WI (United States); Regan, K.A.; Cava, R.J. [Department of Chemistry, Princeton University, Princeton, NJ (United States); Bud' Ko, S.L.; Canfield, P.C.; Finnemore, D.K. [Department of Physics and Astronomy, Iowa State University, Ames, IA (United States)

    2002-04-01

    Grain morphology and crystallographic texture were investigated by electron microscopy in four different polycrystalline forms of superconducting MgB{sub 2}. The materials included a hot-pressed sintered MgB{sub 2} pellet, a pellet reacted in situ from Mg and B, an in situ reacted MgB{sub 2} filament and a pulsed-laser-deposited thin film grown on a single crystalline [111] oriented SrTiO{sub 3} substrate. Thick plate-shaped grains with an aspect ratio of {approx}3 and large faces parallel to (0001) planes dominated the microstructure in all four types of sample. The intermediate-sized plate-shaped grains (0.1{mu}mx0.3{mu}m on average) in the electromagnetically most homogeneous parts of the hot-pressed pellets were strongly facetted, but not textured. Large (3-5 {mu}m) plate-shaped grains were seen in the pellet reacted directly from stoichiometric Mg and B. A tendency for parallel alignment of the [0001] axes of the considerably larger grains ({approx}0.25{mu}mx1{mu}m) in the filament was observed near its W core, but degradation of this texture away from the core was apparent. The very small grains ({approx}10 nm) of the thin film possessed a well-defined fibre texture with [0001] parallel to the film normal and no preferred orientation in the plane of the film. Electrical resistivity of the finest grain samples was some 10{sup 3} times higher than the largest grain sample and their critical current density about one order of magnitude higher. We conclude that, in contrast to the cuprate-based high-T{sub c} superconductors, grain boundaries do not limit the critical current density of polycrystalline MgB{sub 2} and indeed act as flux-pinning centres, which enhance the critical current density. (author)

  2. Loading applied on prosthetic knee of transfemoral amputee: comparison of inverse dynamics and direct measurements.

    Science.gov (United States)

    Dumas, R; Cheze, L; Frossard, L

    2009-11-01

    Inverse dynamics is the most comprehensive method that gives access to the net joint forces and moments during walking. However it is based on assumptions (i.e., rigid segments linked by ideal joints) and it is known to be sensitive to the input data (e.g., kinematic derivatives, positions of joint centres and centre of pressure, inertial parameters). Alternatively, transducers can be used to measure directly the load applied on the residuum of transfemoral amputees. So, the purpose of this study was to compare the forces and moments applied on a prosthetic knee measured directly with the ones calculated by three inverse dynamics computations--corresponding to 3 and 2 segments, and "ground reaction vector technique"--during the gait of one patient. The maximum RMSEs between the estimated and directly measured forces (i.e., 56 N) and moment (i.e., 5 N m) were relatively small. However the dynamic outcomes of the prosthetic components (i.e., absorption of the foot, friction and limit stop of the knee) were only partially assessed with inverse dynamic methods.

  3. Crystallographic Behavior of Iron Oxide Minerals in the Deformed Iron Formation of Quadrilátero Ferrífero

    Science.gov (United States)

    Duarte Lisboa, Filipe Augusto; Lagoeiro, Leonardo; Martins Graça, Leonardo; Ávila, Carlos Fernando; Ferreira Barbosa, Paola

    2016-04-01

    The Quadrilátero Ferrífero (QF) which is located in Brazil represents a mineral province of great importance for hosting Banded Iron Formation deposits (BIFs). The Alegria mine which belongs to Vale Company is located in the east part of Quadrilátero Ferrífero and it explores iron ore from a region of great structural complexity. A deformed BIF sample that presents a micro-fold on quartz and hematite bands was analyzed through Electron Backscatter Diffraction technique (EBSD) in order to relate the crystallographic orientations with the microstructures along the micro-fold envelop. For the sample orientation the Z-axis is taken parallel to the fold limb, Y-axis is perpendicular to the fold hinge and X-axis perpendicular to the YZ plane. In the limbs hematite grains are mostly stretched whereas at the hinge grains tend to be somewhat equant. On the other hand, quartz grain shapes are invariable along the fold, with a few exceptions in the hinge where grains are slightly elongated. Grains of hematite present a strong c-axis ({0001}) preferred orientation forming a subtle girdle somewhat parallel to the XY plane of the strain ellipsoid determined macroscopically (XY being the foliation plane), and a strong () crystallographic fabric approximately parallel to the Z-axis. Similarly, the poles to the prismatic planes ({m} or {10bar10}) also have a stronger crystallographic fabric parallel to the Z axis. It seems that there are two crossing planes for the orientation of and {m} with the two maxima at the intersection of the two planes. Typical hematite crystallographic fabrics are somewhat distinct, since {c} axis commonly forms a very strong fiber texture parallel to the pole of the foliation. Most studies regard such crystallographic texture as evidence for high activity of {c} slip. The {c} girdles observed here are common for mica grains under rigid body rotation in constriction strain, which mechanism is commonly observed in the hematite grains of the sample. The

  4. Inverse magnetic/shear catalysis

    Energy Technology Data Exchange (ETDEWEB)

    McInnes, Brett, E-mail: matmcinn@nus.edu.sg

    2016-05-15

    It is well known that very large magnetic fields are generated when the Quark–Gluon Plasma is formed during peripheral heavy-ion collisions. Lattice, holographic, and other studies strongly suggest that these fields may, for observationally relevant field values, induce “inverse magnetic catalysis”, signalled by a lowering of the critical temperature for the chiral/deconfinement transition. The theoretical basis of this effect has recently attracted much attention; yet so far these investigations have not included another, equally dramatic consequence of the peripheral collision geometry: the QGP acquires a large angular momentum vector, parallel to the magnetic field. Here we use holographic techniques to argue that the angular momentum can also, independently, have an effect on transition temperatures, and we obtain a rough estimate of the relative effects of the presence of both a magnetic field and an angular momentum density. We find that the shearing angular momentum reinforces the effect of the magnetic field at low values of the baryonic chemical potential, but that it can actually decrease that effect at high chemical potentials.

  5. Inversion based on computational simulations

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, K.M.; Cunningham, G.S.; Saquib, S.S.

    1998-09-01

    A standard approach to solving inversion problems that involve many parameters uses gradient-based optimization to find the parameters that best match the data. The authors discuss enabling techniques that facilitate application of this approach to large-scale computational simulations, which are the only way to investigate many complex physical phenomena. Such simulations may not seem to lend themselves to calculation of the gradient with respect to numerous parameters. However, adjoint differentiation allows one to efficiently compute the gradient of an objective function with respect to all the variables of a simulation. When combined with advanced gradient-based optimization algorithms, adjoint differentiation permits one to solve very large problems of optimization or parameter estimation. These techniques will be illustrated through the simulation of the time-dependent diffusion of infrared light through tissue, which has been used to perform optical tomography. The techniques discussed have a wide range of applicability to modeling including the optimization of models to achieve a desired design goal.

  6. Inverse magnetic/shear catalysis

    Directory of Open Access Journals (Sweden)

    Brett McInnes

    2016-05-01

    Full Text Available It is well known that very large magnetic fields are generated when the Quark–Gluon Plasma is formed during peripheral heavy-ion collisions. Lattice, holographic, and other studies strongly suggest that these fields may, for observationally relevant field values, induce “inverse magnetic catalysis”, signalled by a lowering of the critical temperature for the chiral/deconfinement transition. The theoretical basis of this effect has recently attracted much attention; yet so far these investigations have not included another, equally dramatic consequence of the peripheral collision geometry: the QGP acquires a large angular momentum vector, parallel to the magnetic field. Here we use holographic techniques to argue that the angular momentum can also, independently, have an effect on transition temperatures, and we obtain a rough estimate of the relative effects of the presence of both a magnetic field and an angular momentum density. We find that the shearing angular momentum reinforces the effect of the magnetic field at low values of the baryonic chemical potential, but that it can actually decrease that effect at high chemical potentials.

  7. MODEL SELECTION FOR SPECTROPOLARIMETRIC INVERSIONS

    Energy Technology Data Exchange (ETDEWEB)

    Asensio Ramos, A.; Manso Sainz, R.; Martinez Gonzalez, M. J.; Socas-Navarro, H. [Instituto de Astrofisica de Canarias, E-38205, La Laguna, Tenerife (Spain); Viticchie, B. [ESA/ESTEC RSSD, Keplerlaan 1, 2200 AG Noordwijk (Netherlands); Orozco Suarez, D., E-mail: aasensio@iac.es [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan)

    2012-04-01

    Inferring magnetic and thermodynamic information from spectropolarimetric observations relies on the assumption of a parameterized model atmosphere whose parameters are tuned by comparison with observations. Often, the choice of the underlying atmospheric model is based on subjective reasons. In other cases, complex models are chosen based on objective reasons (for instance, the necessity to explain asymmetries in the Stokes profiles) but it is not clear what degree of complexity is needed. The lack of an objective way of comparing models has, sometimes, led to opposing views of the solar magnetism because the inferred physical scenarios are essentially different. We present the first quantitative model comparison based on the computation of the Bayesian evidence ratios for spectropolarimetric observations. Our results show that there is not a single model appropriate for all profiles simultaneously. Data with moderate signal-to-noise ratios (S/Ns) favor models without gradients along the line of sight. If the observations show clear circular and linear polarization signals above the noise level, models with gradients along the line are preferred. As a general rule, observations with large S/Ns favor more complex models. We demonstrate that the evidence ratios correlate well with simple proxies. Therefore, we propose to calculate these proxies when carrying out standard least-squares inversions to allow for model comparison in the future.

  8. Inverse problems and uncertainty quantification

    KAUST Repository

    Litvinenko, Alexander

    2013-12-18

    In a Bayesian setting, inverse problems and uncertainty quantification (UQ)— the propagation of uncertainty through a computational (forward) model—are strongly connected. In the form of conditional expectation the Bayesian update becomes computationally attractive. This is especially the case as together with a functional or spectral approach for the forward UQ there is no need for time- consuming and slowly convergent Monte Carlo sampling. The developed sampling- free non-linear Bayesian update is derived from the variational problem associated with conditional expectation. This formulation in general calls for further discretisa- tion to make the computation possible, and we choose a polynomial approximation. After giving details on the actual computation in the framework of functional or spectral approximations, we demonstrate the workings of the algorithm on a number of examples of increasing complexity. At last, we compare the linear and quadratic Bayesian update on the small but taxing example of the chaotic Lorenz 84 model, where we experiment with the influence of different observation or measurement operators on the update.

  9. Inverse Problems and Uncertainty Quantification

    KAUST Repository

    Litvinenko, Alexander

    2014-01-06

    In a Bayesian setting, inverse problems and uncertainty quantification (UQ) - the propagation of uncertainty through a computational (forward) modelare strongly connected. In the form of conditional expectation the Bayesian update becomes computationally attractive. This is especially the case as together with a functional or spectral approach for the forward UQ there is no need for time- consuming and slowly convergent Monte Carlo sampling. The developed sampling- free non-linear Bayesian update is derived from the variational problem associated with conditional expectation. This formulation in general calls for further discretisa- tion to make the computation possible, and we choose a polynomial approximation. After giving details on the actual computation in the framework of functional or spectral approximations, we demonstrate the workings of the algorithm on a number of examples of increasing complexity. At last, we compare the linear and quadratic Bayesian update on the small but taxing example of the chaotic Lorenz 84 model, where we experiment with the influence of different observation or measurement operators on the update.

  10. Inverse problem in Parker's dynamo

    CERN Document Server

    Reshetnyak, M Yu

    2015-01-01

    The inverse solution of the 1D Parker dynamo equations is considered. The method is based on minimization of the cost-function, which characterize deviation of the model solution properties from the desired ones. The output is the latitude distribution of the magnetic field generation sources: the $\\alpha$- and $\\omega$-effects. Minimization is made using the Monte-Carlo method. The details of the method, as well as some applications, which can be interesting for the broad dynamo community, are considered: conditions when the invisible for the observer at the surface of the planet toroidal part of the magnetic field is much larger than the poloidal counterpart. It is shown that at some particular distributions of $\\alpha$ and $\\omega$ the well-known thesis that sign of the dynamo-number defines equatorial symmetry of the magnetic field to the equator plane, is violated. It is also demonstrated in what circumstances magnetic field in the both hemispheres have different properties, and simple physical explanati...

  11. Inversion and approximation of Laplace transforms

    Science.gov (United States)

    Lear, W. M.

    1980-01-01

    A method of inverting Laplace transforms by using a set of orthonormal functions is reported. As a byproduct of the inversion, approximation of complicated Laplace transforms by a transform with a series of simple poles along the left half plane real axis is shown. The inversion and approximation process is simple enough to be put on a programmable hand calculator.

  12. Integrative inversion of land surface component temperature

    Institute of Scientific and Technical Information of China (English)

    FAN Wenjie; XU Xiru

    2005-01-01

    In this paper, the row winter wheat was selected as the example to study the component temperature inversion method of land surface target in detail. The result showed that the structural pattern of row crop can affect the inversion precision of component temperature evidently. Choosing appropriate structural pattern of row crop can improve the inversion precision significantly. The iterative method combining inverse matrix was a stable method that was fit for inversing component temperature of land surface target. The result of simulation and field experiment showed that the integrative method could remarkably improve the inversion accuracy of the lighted soil surface temperature and the top layer canopy temperature, and enhance inversion stability of components temperature. Just two parameters were sufficient for accurate atmospheric correction of multi-angle and multi-spectral thermal infrared data: atmospheric transmittance and the atmospheric upwelling radiance. If the atmospheric parameters and component temperature can be inversed synchronously, the really and truly accurate atmospheric correction can be achieved. The validation using ATSRII data showed that the method was useful.

  13. Non-Linear Logging Parameters Inversion

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The non-linear logging parameters inversion is based on the field theory, information optimization and predication theory. It uses seismic charaoters,geological model and logging data as a restriction to inverse 2D, 3D logging parameters data volume. Using this method,

  14. Third Harmonic Imaging using a Pulse Inversion

    DEFF Research Database (Denmark)

    Rasmussen, Joachim; Du, Yigang; Jensen, Jørgen Arendt

    2011-01-01

    The pulse inversion (PI) technique can be utilized to separate and enhance harmonic components of a waveform for tissue harmonic imaging. While most ultrasound systems can perform pulse inversion, only few image the 3rd harmonic component. PI pulse subtraction can isolate and enhance the 3rd...

  15. Inversion in Mathematical Thinking and Learning

    Science.gov (United States)

    Greer, Brian

    2012-01-01

    Inversion is a fundamental relational building block both within mathematics as the study of structures and within people's physical and social experience, linked to many other key elements such as equilibrium, invariance, reversal, compensation, symmetry, and balance. Within purely formal arithmetic, the inverse relationships between addition and…

  16. Normal Orthodox Semigroups with Inverse Transversals

    Institute of Scientific and Technical Information of China (English)

    ZHUFeng-lin

    2003-01-01

    A normal orthodox semigroup is an orthodox semigroup whose idempotent elements form a normal band.We deal with congruces on a normal orthodox semigroup with an iverse transversal .A structure theorem for such semigroup is obtained.Munn(1966)gave a fundamental inverse semigroup Following Munn's idea ,we give a fundamental normal orthodox semigroup with an inverse transversal.

  17. Treatment of inverse psoriasis with efalizumab.

    Science.gov (United States)

    George, Dornechia; Rosen, Ted

    2009-01-01

    Various topical and systemic treatments have shown efficacy in plaque and palmoplantar psoriasis; however, studies regarding efficacy in inverse psoriasis are few. The authors present a case of a patient with severe inverse psoriasis who was successfully treated with efalizumab, resulting in complete and sustained remission during prolonged maintenance therapy.

  18. Approximation of the Inverse -Frame Operator

    Indian Academy of Sciences (India)

    M R Abdollahpour; A Najati

    2011-05-01

    In this paper, we introduce the concept of (strong) projection method for -frames which works for all conditional -Riesz frames. We also derive a method for approximation of the inverse -frame operator which is efficient for all -frames. We show how the inverse of -frame operator can be approximated as close as we like using finite-dimensional linear algebra.

  19. An inversion algorithm for general tridiagonal matrix

    Institute of Scientific and Technical Information of China (English)

    Rui-sheng RAN; Ting-zhu HUANG; Xing-ping LIU; Tong-xiang GU

    2009-01-01

    An algorithm for the inverse of a general tridiagonal matrix is presented. For a tridiagonal matrix having the Doolittle factorization, an inversion algorithm is established.The algorithm is then generalized to deal with a general tridiagonal matrix without any restriction. Comparison with other methods is provided, indicating low computational complexity of the proposed algorithm, and its applicability to general tridiagonal matrices.

  20. Resolution analysis in full waveform inversion

    NARCIS (Netherlands)

    Fichtner, A.; Trampert, J.

    2011-01-01

    We propose a new method for the quantitative resolution analysis in full seismic waveform inversion that overcomes the limitations of classical synthetic inversions while being computationally more efficient and applicable to any misfit measure. The method rests on (1) the local quadratic approximat

  1. Metaheuristic optimization of acoustic inverse problems.

    NARCIS (Netherlands)

    van Leijen, A.V.; Rothkrantz, L.; Groen, F.

    2011-01-01

    Swift solving of geoacoustic inverse problems strongly depends on the application of a global optimization scheme. Given a particular inverse problem, this work aims to answer the questions how to select an appropriate metaheuristic search strategy, and how to configure it for optimal performance.

  2. A Construction of Weakly Inverse Semigroups

    Institute of Scientific and Technical Information of China (English)

    Bing Jun YU; Yan LI

    2009-01-01

    Let S° be an inverse semigroup with semilattice biordered set E° of idempotents and E a weakly inverse biordered set with a subsemilattice Ep = { e ∈ E |(V) f ∈ E, S(f , e)(C) w(e) } isomorphic to E° by θ:Ep→E°. In this paper, it is proved that if(V)f, g∈E, f ←→ ,g(→) f°θ (ζ)s° g°θand there exists a mapping φ from Ep into the symmetric weakly inverse semigroup (ζξ)(E ∪S°) satisfying six appropriate conditions, then a weakly inverse semigroup ∑ can be constructed in (ζξ)(S°), called the weakly inverse hull of a weakly inverse system (S°, E, θ, φ) with I(∑) ≌ S°, E(∑) (≌) E. Conversely,every weakly inverse semigroup can be constructed in this way. Furthermore, a sufficient and necessary condition for two weakly inverse hulls to be isomorphic is also given.

  3. Metaheuristic optimization of acoustic inverse problems.

    NARCIS (Netherlands)

    van Leijen, A.V.; Rothkrantz, L.; Groen, F.

    2011-01-01

    Swift solving of geoacoustic inverse problems strongly depends on the application of a global optimization scheme. Given a particular inverse problem, this work aims to answer the questions how to select an appropriate metaheuristic search strategy, and how to configure it for optimal performance. F

  4. Patient-centred continuing professional development for Canadian ...

    African Journals Online (AJOL)

    Improving clinical practice skills can enhance a patient-centred model of health care. ... of patient-centred care important, and whether the perceived importance is ... than men but men rated patient communication skills higher than women.

  5. Inverse scattering: applications to nuclear physics

    CERN Document Server

    Mackintosh, Raymond S

    2012-01-01

    In what follows we first set the context for inverse scattering in nuclear physics with a brief account of inverse problems in general. We then turn to inverse scattering which involves the S-matrix, which connects the interaction potential between two scattering particles with the measured scattering cross section. The term `inverse' is a reference to the fact that instead of determining the scattering S-matrix from the interaction potential between the scattering particles, we do the inverse. That is to say, we calculate the interaction potential from the S-matrix. This review explains how this can now be done reliably, but the emphasis will be upon reasons why one should wish to do this, with an account of some of the ways this can lead to understanding concerning nuclear interactions.

  6. Forward modeling. Route to electromagnetic inversion

    Energy Technology Data Exchange (ETDEWEB)

    Groom, R.; Walker, P. [PetRos EiKon Incorporated, Ontario (Canada)

    1996-05-01

    Inversion of electromagnetic data is a topical subject in the literature, and much time has been devoted to understanding the convergence properties of various inverse methods. The relative lack of success of electromagnetic inversion techniques is partly attributable to the difficulties in the kernel forward modeling software. These difficulties come in two broad classes: (1) Completeness and robustness, and (2) convergence, execution time and model simplicity. If such problems exist in the forward modeling kernel, it was demonstrated that inversion can fail to generate reasonable results. It was suggested that classical inversion techniques, which are based on minimizing a norm of the error between data and the simulated data, will only be successful when these difficulties in forward modeling kernels are properly dealt with. 4 refs., 5 figs.

  7. Recurrent Neural Network for Computing Outer Inverse.

    Science.gov (United States)

    Živković, Ivan S; Stanimirović, Predrag S; Wei, Yimin

    2016-05-01

    Two linear recurrent neural networks for generating outer inverses with prescribed range and null space are defined. Each of the proposed recurrent neural networks is based on the matrix-valued differential equation, a generalization of dynamic equations proposed earlier for the nonsingular matrix inversion, the Moore-Penrose inversion, as well as the Drazin inversion, under the condition of zero initial state. The application of the first approach is conditioned by the properties of the spectrum of a certain matrix; the second approach eliminates this drawback, though at the cost of increasing the number of matrix operations. The cases corresponding to the most common generalized inverses are defined. The conditions that ensure stability of the proposed neural network are presented. Illustrative examples present the results of numerical simulations.

  8. Fast wavelet based sparse approximate inverse preconditioner

    Energy Technology Data Exchange (ETDEWEB)

    Wan, W.L. [Univ. of California, Los Angeles, CA (United States)

    1996-12-31

    Incomplete LU factorization is a robust preconditioner for both general and PDE problems but unfortunately not easy to parallelize. Recent study of Huckle and Grote and Chow and Saad showed that sparse approximate inverse could be a potential alternative while readily parallelizable. However, for special class of matrix A that comes from elliptic PDE problems, their preconditioners are not optimal in the sense that independent of mesh size. A reason may be that no good sparse approximate inverse exists for the dense inverse matrix. Our observation is that for this kind of matrices, its inverse entries typically have piecewise smooth changes. We can take advantage of this fact and use wavelet compression techniques to construct a better sparse approximate inverse preconditioner. We shall show numerically that our approach is effective for this kind of matrices.

  9. Inverse m-matrices and ultrametric matrices

    CERN Document Server

    Dellacherie, Claude; San Martin, Jaime

    2014-01-01

    The study of M-matrices, their inverses and discrete potential theory is now a well-established part of linear algebra and the theory of Markov chains. The main focus of this monograph is the so-called inverse M-matrix problem, which asks for a characterization of nonnegative matrices whose inverses are M-matrices. We present an answer in terms of discrete potential theory based on the Choquet-Deny Theorem. A distinguished subclass of inverse M-matrices is ultrametric matrices, which are important in applications such as taxonomy. Ultrametricity is revealed to be a relevant concept in linear algebra and discrete potential theory because of its relation with trees in graph theory and mean expected value matrices in probability theory. Remarkable properties of Hadamard functions and products for the class of inverse M-matrices are developed and probabilistic insights are provided throughout the monograph.

  10. Energy Efficiency Improvements Using DC in Data Centres

    OpenAIRE

    Bergqvist, Sofia

    2011-01-01

    The installed power usage in a data centre will often amount to several megawatts (MW). Thetotal power consumption of the data centres in the world is comparable to that of the airtraffic. The high energy costs and carbon dioxide emissions resulting from the operation of adata centre call for alternative, more efficient, solutions for the power supply design. Oneproposed solution to decrease the energy usage is to use a direct current power supply (DCUPS) for all the servers in the data centr...

  11. Tele-centres as a way of achieving universal access

    DEFF Research Database (Denmark)

    Falch, Morten; Anyimadu, Amos

    2003-01-01

    The success of tele-centres in Ghana is discussed. The tele-centres offer a low cost opportunity to empower local communities in developed and developing countries to meet the challenges of the information society. The tele-centres can also contribute more directly to the supply of non-commercial...

  12. Reaching the Students that Student-Centred Learning Cannot Reach

    Science.gov (United States)

    Hockings, Christine

    2009-01-01

    Student-centred learning has the potential to engage a more academically diverse student body than the more conventional teacher-centred approaches. In spite of the evidence in favour of student-centred learning, a recent study showed that it was ineffective for around 30% of undergraduates in a large and diverse group studying business operations…

  13. Identification of polymorphic inversions from genotypes

    Directory of Open Access Journals (Sweden)

    Cáceres Alejandro

    2012-02-01

    Full Text Available Abstract Background Polymorphic inversions are a source of genetic variability with a direct impact on recombination frequencies. Given the difficulty of their experimental study, computational methods have been developed to infer their existence in a large number of individuals using genome-wide data of nucleotide variation. Methods based on haplotype tagging of known inversions attempt to classify individuals as having a normal or inverted allele. Other methods that measure differences between linkage disequilibrium attempt to identify regions with inversions but unable to classify subjects accurately, an essential requirement for association studies. Results We present a novel method to both identify polymorphic inversions from genome-wide genotype data and classify individuals as containing a normal or inverted allele. Our method, a generalization of a published method for haplotype data 1, utilizes linkage between groups of SNPs to partition a set of individuals into normal and inverted subpopulations. We employ a sliding window scan to identify regions likely to have an inversion, and accumulation of evidence from neighboring SNPs is used to accurately determine the inversion status of each subject. Further, our approach detects inversions directly from genotype data, thus increasing its usability to current genome-wide association studies (GWAS. Conclusions We demonstrate the accuracy of our method to detect inversions and classify individuals on principled-simulated genotypes, produced by the evolution of an inversion event within a coalescent model 2. We applied our method to real genotype data from HapMap Phase III to characterize the inversion status of two known inversions within the regions 17q21 and 8p23 across 1184 individuals. Finally, we scan the full genomes of the European Origin (CEU and Yoruba (YRI HapMap samples. We find population-based evidence for 9 out of 15 well-established autosomic inversions, and for 52 regions

  14. Post Stack Seismic data-impedance Inversion using Multi-Point Stochastic Inversion in Yme field, Norwegian Sea

    OpenAIRE

    Inácio, Celso dos Santos Laurinda

    2011-01-01

    The Multi-Point Stochastic Inversion (MPSI) is a method based on both deterministic inversion and stochastic inversion. The deterministic inversion is used prior to the stochastic inversion and it is more general and works well for thick layers while the stochastic inversion works well for thin layers. Because of its combination, the MPSI method is one of suitable methods for reservoir characterization. Apart from being used for post-stack seismic acoustic impedance (AI) inversion, the MPSI m...

  15. The "Magic" of Tutorial Centres in Hong Kong: An Analysis of Media Marketing and Pedagogy in a Tutorial Centre

    Science.gov (United States)

    Koh, Aaron

    2014-01-01

    Why do more than three-quarters of Hong Kong's senior secondary students flock to tutorial centres like moths to light? What is the "magic" that is driving the popularity of the tutorial centre enterprise? Indeed, looking at the ongoing boom of tutorial centres in Hong Kong (there are almost 1,000 of them), it is difficult not to ask…

  16. Low energy use at Vaestervik sports centre

    Energy Technology Data Exchange (ETDEWEB)

    2009-05-15

    Vaestervik, in south Sweden, has saved both energy and money since modern energy efficiency equipment was installed in its swimming pool and bowling alley. Energy use in the sports centre has so far fallen by around 830 MWh/year, and operating costs have been reduced by efficient heat recovery. Energy efficiency at the Vaestervik sports centre is a good example of how a local authority can save energy and money by installing modern equipment for ventilation and heat recovery in a facility with high energy consumption. The well-used sports centre, including a swimming pool and bowling alley, is in central Vaestervik. In 1999 the Municipality received grants from the local investment programme (LIP) to improve the facility's energy efficiency. An efficient ventilation system with a dehumidifier and heat exchanger was installed at the swimming pool, reducing the need to introduce cold air. In addition the bowling alley, which did not have heat recovery, was given a modern heat-recovery plant. - Lower operating costs due to efficient heat recovery. - Reduced energy use (electricity and district heating) for the plant at around 830 MWh/year. The modern and highly efficient units for heat recovery, dehumidification and heat exchange result in lower operating costs and reduced energy use, which means that the Municipality of Vaestervik saves energy and money. Installation at the swimming pool resulted in slightly higher air humidity, but a relative humidity of 60% is common in swimming pools and difficult to reduce without inconveniencing bathers. A new fan room installed in the roof contributed to higher than anticipated costs, but the financial and economic gains outweigh these. New frequency-controlled circulation pumps for the pool water were installed in 2007. They are to have occupancy control capability, giving a further improvement of energy saving and heat recovery

  17. Sparse CSEM inversion driven by seismic coherence

    Science.gov (United States)

    Guo, Zhenwei; Dong, Hefeng; Kristensen, Åge

    2016-12-01

    Marine controlled source electromagnetic (CSEM) data inversion for hydrocarbon exploration is often challenging due to high computational cost, physical memory requirement and low resolution of the obtained resistivity map. This paper aims to enhance both the speed and resolution of CSEM inversion by introducing structural geological information in the inversion algorithm. A coarse mesh is generated for Occam’s inversion, where the parameters are fewer than in the fine regular mesh. This sparse mesh is defined as a coherence-based irregular (IC) sparse mesh, which is based on vertices extracted from available geological information. Inversion results on synthetic data illustrate that the IC sparse mesh has a smaller inversion computational cost compared to the regular dense (RD) mesh. It also has a higher resolution than with a regular sparse (RS) mesh for the same number of estimated parameters. In order to study how the IC sparse mesh reduces the computational time, four different meshes are generated for Occam’s inversion. As a result, an IC sparse mesh can reduce the computational cost while it keeps the resolution as good as a fine regular mesh. The IC sparse mesh reduces the computational cost of the matrix operation for model updates. When the number of estimated parameters reduces to a limited value, the computational cost is independent of the number of parameters. For a testing model with two resistive layers, the inversion result using an IC sparse mesh has higher resolution in both horizontal and vertical directions. Overall, the model representing significant geological information in the IC mesh can improve the resolution of the resistivity models obtained from inversion of CSEM data.

  18. On the inversion-indel distance.

    Science.gov (United States)

    Willing, Eyla; Zaccaria, Simone; Braga, Marília D V; Stoye, Jens

    2013-01-01

    The inversion distance, that is the distance between two unichromosomal genomes with the same content allowing only inversions of DNA segments, can be computed thanks to a pioneering approach of Hannenhalli and Pevzner in 1995. In 2000, El-Mabrouk extended the inversion model to allow the comparison of unichromosomal genomes with unequal contents, thus insertions and deletions of DNA segments besides inversions. However, an exact algorithm was presented only for the case in which we have insertions alone and no deletion (or vice versa), while a heuristic was provided for the symmetric case, that allows both insertions and deletions and is called the inversion-indel distance. In 2005, Yancopoulos, Attie and Friedberg started a new branch of research by introducing the generic double cut and join (DCJ) operation, that can represent several genome rearrangements (including inversions). Among others, the DCJ model gave rise to two important results. First, it has been shown that the inversion distance can be computed in a simpler way with the help of the DCJ operation. Second, the DCJ operation originated the DCJ-indel distance, that allows the comparison of genomes with unequal contents, considering DCJ, insertions and deletions, and can be computed in linear time. In the present work we put these two results together to solve an open problem, showing that, when the graph that represents the relation between the two compared genomes has no bad components, the inversion-indel distance is equal to the DCJ-indel distance. We also give a lower and an upper bound for the inversion-indel distance in the presence of bad components.

  19. Optimal catchment area and primary PCI centre volume revisited

    DEFF Research Database (Denmark)

    Schoos, Mikkel Malby; Pedersen, Frants; Holmvang, Lene

    2015-01-01

    AIMS: The currently stated optimal catchment population for a pPCI centre is 300,000-1,100,000, resulting in 200-800 procedures/year. pPCI centres are increasing in number even within small geographic areas. We describe the organisation and quality of care after merging two high-volume centres....... The quality of a centre reflects governance, training, resources and pre-hospital triage, rather than catchment population and STEMI incidence, as long as a minimum volume is guaranteed. Resources can be utilised better by merging neighbouring centres, without negative effects on quality of care....

  20. The INTEGRAL science data centre (ISDC)

    DEFF Research Database (Denmark)

    Courvoisier, T.J.L.; Walter, Rasmus; Beckmann, V.;

    2003-01-01

    The INTEGRAL Science Data Centre (ISDC) provides the INTEGRAL data and means to analyse them to the scientific community. The ISDC runs a gamma ray burst alert system that provides the position of gamma ray bursts on the sky within seconds to the community. It operates a quick-look analysis...... of the data within few hours that detects new and unexpected sources as well as it monitors the instruments. The ISDC processes the data through a standard analysis the results of which are provided to the observers together with their data....

  1. going for the centre of the world

    Directory of Open Access Journals (Sweden)

    Moses Iten

    2005-08-01

    Full Text Available “He wants to go to the centre!” exclaims the man I’ve just asked for directions, winking to his friends. They are laying a cement foundation for a house, amongst wooden huts with dirt floors. An upgrade. They giggle and wave for me to continue along the only road. At each house - spaced fifty metres from each other - I keep asking for the same directions. “El Centro?” a lady asks me at one of the many wooden kiosks, that all seem to sell the same few things, “bueno, just take a left at the next crossing.”

  2. Dynamics of B cells in germinal centres.

    Science.gov (United States)

    De Silva, Nilushi S; Klein, Ulf

    2015-03-01

    Humoral immunity depends on the germinal centre (GC) reaction during which somatically mutated high-affinity memory B cells and plasma cells are generated. Recent studies have uncovered crucial cues that are required for the formation and the maintenance of GCs and for the selection of high-affinity antibody mutants. In addition, it is now clear that these events are promoted by the dynamic movements of cells within and between GCs. These findings have resolved the complexities of the GC reaction in greater detail than ever before. This Review focuses on these recent advances and discusses their implications for the establishment of humoral immunity.

  3. Biological Inspiration in Human Centred Robotics

    Institute of Scientific and Technical Information of China (English)

    HU Huo-sheng; LIU Jin-dong; Calderon Carlos A

    2004-01-01

    Human centred robotics (HCR) concerns with the development of various kinds of intelligent systems and robots that will be used in environments coexisting with humans. These systems and robots will be interactive and useful assistants/companions for people in different ages, situations, activities and environments in order to improve the quality of life. This paper presents the autors' current research work toward the development of advanced theory and technologies for HCR applications, based on inspiration from biological systems. More specifically, both bio-mimetic system modelling and robot learning by imitation are discussed respectively, and some preliminary results are demonstrated.

  4. Effect of crystallographic texture and dislocation hardening on limit strain in sheet metal forming

    Science.gov (United States)

    Wen, Xiyu

    2000-10-01

    In the metal industry, sheet metals are widely used to produce packaging materials for consumer goods, for structures such as automobilse, and for building construction and transportation. The desired shape of the products is imparted by plastic deformation in either the cold or hot state. Traditionally, the prediction of the forming limit of sheet metals is based on tensile tests, simulation tests and continuum mathematical models. Continuum models used in the prediction of the plastic behavior of sheet metals are based on average values of mechanical properties such as elongation, yield strength, work hardening and work-hardening rate, which are usually derived from tensile tests. Although attempts have been made to abandon the phenomenological description of the yield function by applying the theory of crystal plasticity to calculate the yield surface of texture polycrystals and hence the limit strains, only the average properties of the microstructure (e.g., the crystallographic texture of the bulk sheet) have been taken into account. So far, there has been no model for the prediction of the strain path and the limit strain of sheet metals that takes into account the effect of individual grain orientation and the dislocation property. In this thesis, different approaches in the study of plastic deformation are reviewed from the view-point of both macroplasticity and microplasticity. Instead of relying on a unique flow rule to describe the stress and strain relationship, the role of work hardening in the instability process of sheet metal and hence the flow localization phenomenon is explored from a study of the changes in the orientation of the constituent crystallites and from the changes in the dislocation density associated with different grain orientations during the course of large biaxial deformation. The changes in the crystallographic textures of an aluminium sheet sample deformed under various stress states from plane-strain tension to equi

  5. Crystal growth and first crystallographic characterization of mixed uranium(IV)-plutonium(III) oxalates.

    Science.gov (United States)

    Tamain, Christelle; Arab Chapelet, Bénédicte; Rivenet, Murielle; Abraham, Francis; Caraballo, Richard; Grandjean, Stéphane

    2013-05-06

    The mixed-actinide uranium(IV)-plutonium(III) oxalate single crystals (NH4)0.5[Pu(III)0.5U(IV)0.5(C2O4)2·H2O]·nH2O (1) and (NH4)2.7Pu(III)0.7U(IV)1.3(C2O4)5·nH2O (2) have been prepared by the diffusion of different ions through membranes separating compartments of a triple cell. UV-vis, Raman, and thermal ionization mass spectrometry analyses demonstrate the presence of both uranium and plutonium metal cations with conservation of the initial oxidation state, U(IV) and Pu(III), and the formation of mixed-valence, mixed-actinide oxalate compounds. The structure of 1 and an average structure of 2 were determined by single-crystal X-ray diffraction and were solved by direct methods and Fourier difference techniques. Compounds 1 and 2 are the first mixed uranium(IV)-plutonium(III) compounds to be structurally characterized by single-crystal X-ray diffraction. The structure of 1, space group P4/n, a = 8.8558(3) Å, b = 7.8963(2) Å, Z = 2, consists of layers formed by four-membered rings of the two actinide metals occupying the same crystallographic site connected through oxalate ions. The actinide atoms are nine-coordinated by oxygen atoms from four bidentate oxalate ligands and one water molecule, which alternates up and down the layer. The single-charged cations and nonbonded water molecules are disordered in the same crystallographic site. For compound 2, an average structure has been determined in space group P6/mmm with a = 11.158(2) Å and c = 6.400(1) Å. The honeycomb-like framework [Pu(III)0.7U(IV)1.3(C2O4)5](2.7-) results from a three-dimensional arrangement of mixed (U0.65Pu0.35)O10 polyhedra connected by five bis-bidentate μ(2)-oxalate ions in a trigonal-bipyramidal configuration.

  6. Graph inverse semigroups: their characterization and completion

    CERN Document Server

    Jones, David G

    2011-01-01

    Graph inverse semigroups generalize the polycyclic inverse monoids and play an important role in the theory of C*-algebras. This paper has two main goals: first, to provide an abstract characterization of graph inverse semigroups; and second, to show how they may be completed, under suitable conditions, to form what we call the Cuntz-Krieger semigroup of the graph. This semigroup is the ample semigroup of a topological groupoid associated with the graph, and the semigroup analogue of the Leavitt path algebra of the graph.

  7. 3rd Annual Workshop on Inverse Problem

    CERN Document Server

    2015-01-01

    This proceeding volume is based on papers presented on the Third Annual Workshop on Inverse Problems which was organized by the Department of Mathematical Sciences, Chalmers University of Technology and University of Gothenburg, and took place in May 2013 in Stockholm. The purpose of this workshop was to present new analytical developments and numerical techniques for solution of inverse problems for a wide range of applications in acoustics, electromagnetics, optical fibers, medical imaging, geophysics, etc. The contributions in this volume reflect these themes and will be beneficial to researchers who are working in the area of applied inverse problems.

  8. Parallel Algorithm in Surface Wave Waveform Inversion

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In Surface wave waveform inversion, we want to reconstruct 3Dshear wav e velocity structure, which calculation beyond the capability of the powerful pr esent day personal computer or even workstation. So we designed a high parallele d algorithm and carried out the inversion on Parallel computer based on the part itioned waveform inversion (PWI). It partitions the large scale optimization pro blem into a number of independent small scale problems and reduces the computati onal effort by several orders of magnitude. We adopted surface waveform inversio n with a equal block(2°×2°) discretization.

  9. New recursive algorithm for matrix inversion

    Institute of Scientific and Technical Information of China (English)

    Cao Jianshu; Wang Xuegang

    2008-01-01

    To reduce the computational complexity of matrix inversion, which is the majority of processing in many practical applications, two numerically efficient recursive algorithms (called algorithms Ⅰ and Ⅱ, respectively)are presented. Algorithm Ⅰ is used to calculate the inverse of such a matrix, whose leading principal minors are all nonzero. Algorithm Ⅱ, whereby, the inverse of an arbitrary nonsingular matrix can be evaluated is derived via improving the algorithm Ⅰ. The implementation, for algorithm Ⅱ or Ⅰ, involves matrix-vector multiplications and vector outer products. These operations are computationally fast and highly parallelizable. MATLAB simulations show that both recursive algorithms are valid.

  10. Nonlinear system compound inverse control method

    Institute of Scientific and Technical Information of China (English)

    Yan ZHANG; Zengqiang CHEN; Peng YANG; Zhuzhi YUAN

    2005-01-01

    A compound neural network is utilized to identify the dynamic nonlinear system.This network is composed of two parts: one is a linear neural network,and the other is a recurrent neural network.Based on the inverse theory a compound inverse control method is proposed.The controller has also two parts:a linear controller and a nonlinear neural network controller.The stability condition of the closed-loop neural network-based compound inverse control system is demonstrated based on the Lyapunov theory.Simulation studies have shown that this scheme is simple and has good control accuracy and robustness.

  11. Voxel inversion of airborne EM data

    DEFF Research Database (Denmark)

    Fiandaca, Gianluca G.; Auken, Esben; Christiansen, Anders Vest C A.V.C.;

    2013-01-01

    We present a geophysical inversion algorithm working directly in a voxel grid disconnected from the actual measuring points, which allows for straightforward integration of different data types in joint inversion, for informing geological/hydrogeological models directly and for easier incorporation...... for jointly inverting airborne and ground-based geophysical data. Furthermore, geological and groundwater models most often refer to a regular voxel grid not correlated to the geophysical model space, and incorporating the geophysical data into the geological/hydrological modelling grids is problematic. We...... present a voxel grid inversion routine that overcomes these problems and we discuss in detail the algorithm implementation....

  12. Analysis of Temperature Distributions in Nighttime Inversions

    Science.gov (United States)

    Telyak, Oksana; Krasouski, Aliaksandr; Svetashev, Alexander; Turishev, Leonid; Barodka, Siarhei

    2015-04-01

    Adequate prediction of temperature inversion in the atmospheric boundary layer is one of prerequisites for successful forecasting of meteorological parameters and severe weather events. Examples include surface air temperature and precipitation forecasting as well as prediction of fog, frosts and smog with hazardous levels of atmospheric pollution. At the same time, reliable forecasting of temperature inversions remains an unsolved problem. For prediction of nighttime inversions over some specific territory, it is important to study characteristic features of local circulation cells formation and to properly take local factors into account to develop custom modeling techniques for operational use. The present study aims to investigate and analyze vertical temperature distributions in tropospheric inversions (isotherms) over the territory of Belarus. We study several specific cases of formation, evolution and decay of deep nighttime temperature inversions in Belarus by means of mesoscale numerical simulations with WRF model, considering basic mechanisms of isothermal and inverse temperature layers formation in the troposphere and impact of these layers on local circulation cells. Our primary goal is to assess the feasibility of advance prediction of inversions formation with WRF. Modeling results reveal that all cases under consideration have characteristic features of radiative inversions (e.g., their formation times, development phases, inversion intensities, etc). Regions of "blocking" layers formation are extensive and often spread over the entire territory of Belarus. Inversions decay starts from the lowermost (near surface) layer (altitudes of 5 to 50 m). In all cases, one can observe formation of temperature gradients that substantially differ from the basic inversion gradient, i.e. the layer splits into smaller layers, each having a different temperature stratification (isothermal, adiabatic, etc). As opposed to various empirical techniques as well as

  13. BOOK REVIEW: Inverse Problems. Activities for Undergraduates

    Science.gov (United States)

    Yamamoto, Masahiro

    2003-06-01

    This book is a valuable introduction to inverse problems. In particular, from the educational point of view, the author addresses the questions of what constitutes an inverse problem and how and why we should study them. Such an approach has been eagerly awaited for a long time. Professor Groetsch, of the University of Cincinnati, is a world-renowned specialist in inverse problems, in particular the theory of regularization. Moreover, he has made a remarkable contribution to educational activities in the field of inverse problems, which was the subject of his previous book (Groetsch C W 1993 Inverse Problems in the Mathematical Sciences (Braunschweig: Vieweg)). For this reason, he is one of the most qualified to write an introductory book on inverse problems. Without question, inverse problems are important, necessary and appear in various aspects. So it is crucial to introduce students to exercises in inverse problems. However, there are not many introductory books which are directly accessible by students in the first two undergraduate years. As a consequence, students often encounter diverse concrete inverse problems before becoming aware of their general principles. The main purpose of this book is to present activities to allow first-year undergraduates to learn inverse theory. To my knowledge, this book is a rare attempt to do this and, in my opinion, a great success. The author emphasizes that it is very important to teach inverse theory in the early years. He writes; `If students consider only the direct problem, they are not looking at the problem from all sides .... The habit of always looking at problems from the direct point of view is intellectually limiting ...' (page 21). The book is very carefully organized so that teachers will be able to use it as a textbook. After an introduction in chapter 1, sucessive chapters deal with inverse problems in precalculus, calculus, differential equations and linear algebra. In order to let one gain some insight

  14. Ellipsoidal head model for fetal magnetoencephalography: forward and inverse solutions

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez, David [Department of Bioengineering, University of Illinois at Chicago, 851 S. Morgan St (M/C 063), Chicago, IL 60607-7053 (United States); Nehorai, Arye [Department of Bioengineering, University of Illinois at Chicago, 851 S. Morgan St (M/C 063), Chicago, IL 60607-7053 (United States); Department of Electrical and Computer Engineering, University of Illinois at Chicago, 851 S. Morgan St, 1120 SEO (M/C 154), Chicago, IL 60607-7053 (United States); Preissl, Hubert [Department of Obstetrics and Gynecology, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States); MEG-Center, University of Tuebingen, Tuebingen, 72206 (Germany)

    2005-05-07

    Fetal magnetoencephalography (fMEG) is a non-invasive technique where measurements of the magnetic field outside the maternal abdomen are used to infer the source location and signals of the fetus' neural activity. There are a number of aspects related to fMEG modelling that must be addressed, such as the conductor volume, fetal position and orientation, gestation period, etc. We propose a solution to the forward problem of fMEG based on an ellipsoidal head geometry. This model has the advantage of highlighting special characteristics of the field that are inherent to the anisotropy of the human head, such as the spread and orientation of the field in relationship with the localization and position of the fetal head. Our forward solution is presented in the form of a kernel matrix that facilitates the solution of the inverse problem through decoupling of the dipole localization parameters from the source signals. Then, we use this model and the maximum likelihood technique to solve the inverse problem assuming the availability of measurements from multiple trials. The applicability and performance of our methods are illustrated through numerical examples based on a real 151-channel SQUID fMEG measurement system (SARA). SARA is an MEG system especially designed for fetal assessment and is currently used for heart and brain studies. Finally, since our model requires knowledge of the best-fitting ellipsoid's centre location and semiaxes lengths, we propose a method for estimating these parameters through a least-squares fit on anatomical information obtained from three-dimensional ultrasound images.

  15. WISB: Warwick Integrative Synthetic Biology Centre.

    Science.gov (United States)

    McCarthy, John

    2016-06-15

    Synthetic biology promises to create high-impact solutions to challenges in the areas of biotechnology, human/animal health, the environment, energy, materials and food security. Equally, synthetic biologists create tools and strategies that have the potential to help us answer important fundamental questions in biology. Warwick Integrative Synthetic Biology (WISB) pursues both of these mutually complementary 'build to apply' and 'build to understand' approaches. This is reflected in our research structure, in which a core theme on predictive biosystems engineering develops underpinning understanding as well as next-generation experimental/theoretical tools, and these are then incorporated into three applied themes in which we engineer biosynthetic pathways, microbial communities and microbial effector systems in plants. WISB takes a comprehensive approach to training, education and outreach. For example, WISB is a partner in the EPSRC/BBSRC-funded U.K. Doctoral Training Centre in synthetic biology, we have developed a new undergraduate module in the subject, and we have established five WISB Research Career Development Fellowships to support young group leaders. Research in Ethical, Legal and Societal Aspects (ELSA) of synthetic biology is embedded in our centre activities. WISB has been highly proactive in building an international research and training network that includes partners in Barcelona, Boston, Copenhagen, Madrid, Marburg, São Paulo, Tartu and Valencia.

  16. KNMI Data Centre: Easy access for all

    Science.gov (United States)

    van de Vegte, John; Som de Cerff, Wim; Plieger, Maarten; de Vreede, Ernst; Sluiter, Raymond; Willem Noteboom, Jan; van der Neut, Ian; Verhoef, Hans; van Versendaal, Robert; van Binnendijk, Martin; Kalle, Henk; Knopper, Arthur; Spit, Jasper; Mastop, Joeri; Klos, Olaf; Calis, Gijs; Ha, Siu-Siu; van Moosel, Wim; Klein Ikkink, Henk-Jan; Tosun, Tuncay

    2013-04-01

    KNMI is the Dutch institute for weather, climate research and seismology. It disseminates weather information to the public at large, the government, aviation and the shipping industry in the interest of safety, the economy and a sustainable environment. To gain insight into long-term developments KNMI conducts research on climate change. Making the knowledge, data and information on hand at KNMI accessible is one core activity. A huge part of the KNMI information is from numerical models, insitu sensor networks and remote sensing satellites. This digital collection is mostly internal only available and is a collection of non searchable , non standardized file formats, lacking documentation and has no references to scientific publications. With the KNMI Data Centre (KDC) project these issues are tackled. In the project a user driven development approach with SCRUM was chosen to get maximum user involvement in a relative short development timeframe. Building on open standards and proven open source technology (which includes in-house developed software like ADAGUC WMS and Portal) resulted in a first release in December 2012 This presentation will focus on the aspects of KDC relating to its technical challenges, the development strategy and the initial usage results of the data centre.

  17. ALICE opens its new nerve centre

    CERN Multimedia

    Antonella Del Rosso

    2014-01-01

    Twenty-nine fully equipped and ergonomic workstations, one meeting area and 11 large format screens in a completely refurbished room: the ALICE Run Control Centre (ARC) implements the best and newest solutions for its shift workers and expert operators, including access for persons with reduced mobility and very soon a magic window for Point 2 visitors.   The ALICE Run Control Centre. “Our initial intention was just to optimise the old layout,” says Federico Ronchetti from Laboratori Nazionali di Frascati (Italy), a CERN scientific associate currently appointed as ALICE Run Coordinator and person in charge of the ALICE Consolidation Task Force. “However, during the review process, we carried out a study of all the existing control rooms at CERN and became aware we needed a radical change. Hence we started planning a complete redesign of the workspace.” Designed and equipped over many years, the old ALICE control room did not have enough space to fit al...

  18. CMS tracker slides into centre stage

    CERN Multimedia

    2006-01-01

    As preparations for the magnet test and cosmic challenge get underway, a prototype tracker has been carefully inserted into the centre of CMS. The tracker, in its special platform, is slowly inserted into the centre of CMS. The CMS prototype tracker to be used for the magnet test and cosmic challenge coming up this summer has the same dimensions -2.5 m in diameter and 6 m in length- as the real one and tooling exactly like it. However, the support tube is only about 1% equipped, with 2 m2 of silicon detectors installed out of the total 200 m2. This is already more than any LEP experiment ever used and indicates the great care needed to be taken by engineers and technicians as these fragile detectors were installed and transported to Point 5. Sixteen thousand silicon detectors with a total of about 10 million strips will make up the full tracker. So far, 140 modules with about 100 000 strips have been implanted into the prototype tracker. These silicon strips will provide precision tracking for cosmic muon...

  19. Probabilistic 3-D time-lapse inversion of magnetotelluric data: Application to an enhanced geothermal system

    Science.gov (United States)

    Rosas-Carbajal, Marina; Linde, Nicolas; Peacock, Jared R.; Zyserman, F. I.; Kalscheuer, Thomas; Thiel, Stephan

    2015-01-01

    Surface-based monitoring of mass transfer caused by injections and extractions in deep boreholes is crucial to maximize oil, gas and geothermal production. Inductive electromagnetic methods, such as magnetotellurics, are appealing for these applications due to their large penetration depths and sensitivity to changes in fluid conductivity and fracture connectivity. In this work, we propose a 3-D Markov chain Monte Carlo inversion of time-lapse magnetotelluric data to image mass transfer following a saline fluid injection. The inversion estimates the posterior probability density function of the resulting plume, and thereby quantifies model uncertainty. To decrease computation times, we base the parametrization on a reduced Legendre moment decomposition of the plume. A synthetic test shows that our methodology is effective when the electrical resistivity structure prior to the injection is well known. The centre of mass and spread of the plume are well retrieved.We then apply our inversion strategy to an injection experiment in an enhanced geothermal system at Paralana, South Australia, and compare it to a 3-D deterministic time-lapse inversion. The latter retrieves resistivity changes that are more shallow than the actual injection interval, whereas the probabilistic inversion retrieves plumes that are located at the correct depths and oriented in a preferential north-south direction. To explain the time-lapse data, the inversion requires unrealistically large resistivity changes with respect to the base model. We suggest that this is partly explained by unaccounted subsurface heterogeneities in the base model from which time-lapse changes are inferred.

  20. Crystallographic orientation and electrode nature are key factors for electric current generation by Geobacter sulfurreducens.

    Science.gov (United States)

    Maestro, Beatriz; Ortiz, Juan M; Schrott, Germán; Busalmen, Juan P; Climent, Víctor; Feliu, Juan M

    2014-08-01

    We have investigated the influence of electrode material and crystallographic structure on electron transfer and biofilm formation of Geobacter sulfurreducens. Single-crystal gold-Au(110), Au(111), Au(210)-and platinum-Pt(100), Pt(110), Pt(111), Pt(210)-electrodes were tested and compared to graphite rods. G. sulfurreducens electrochemically interacts with all these materials with different attachment kinetics and final current production, although redox species involved in the electron transfer to the anode are virtually the same in all cases. Initial bacterial colonization was fastest on graphite up to the monolayer level, whereas gold electrodes led to higher final current densities. Crystal geometry was shown to have an important influence, with Au(210) sustaining a current density of up to 1442±101μAcm(-2) at the steady state, over Au(111) with 961±94μAcm(-2) and Au(110) with 944±89μAcm(-2). On the other hand, the platinum electrodes displayed the lowest performances, including Pt(210). Our results indicate that both crystal geometry and electrode material are key parameters for the efficient interaction of bacteria with the substrate and should be considered for the design of novel materials and microbial devices to optimize energy production.

  1. Synthetic, crystallographic, and computational study of copper(II) complexes of ethylenediaminetetracarboxylate ligands.

    Science.gov (United States)

    Matović, Zoran D; Miletić, Vesna D; Ćendić, Marina; Meetsma, Auke; van Koningsbruggen, Petra J; Deeth, Robert J

    2013-02-04

    Copper(II) complexes of hexadentate ethylenediaminetetracarboxylic acid type ligands H(4)eda3p and H(4)eddadp (H(4)eda3p = ethylenediamine-N-acetic-N,N',N'-tri-3-propionic acid; H(4)eddadp = ethylenediamine-N,N'-diacetic-N,N'-di-3-propionic acid) have been prepared. An octahedral trans(O(6)) geometry (two propionate ligands coordinated in axial positions) has been established crystallographically for the Ba[Cu(eda3p)]·8H(2)O compound, while Ba[Cu(eddadp)]·8H(2)O is proposed to adopt a trans(O(5)) geometry (two axial acetates) on the basis of density functional theory calculations and comparisons of IR and UV-vis spectral data. Experimental and computed structural data correlating similar copper(II) chelate complexes have been used to better understand the isomerism and departure from regular octahedral geometry within the series. The in-plane O-Cu-N chelate angles show the smallest deviation from the ideal octahedral value of 90°, and hence the lowest strain, for the eddadp complex with two equatorial β-propionate rings. A linear dependence between tetragonality and the number of five-membered rings has been established. A natural bonding orbital analysis of the series of complexes is also presented.

  2. On elliptic Calogero-Moser systems for complex crystallographic reflection groups

    CERN Document Server

    Etingof, Pavel; Ma, Xiaoguang; Veselov, Alexander

    2010-01-01

    To every irreducible finite crystallographic reflection group (i.e., an irreducible finite reflection group G acting faithfully on an abelian variety X), we attach a family of classical and quantum integrable systems on X (with meromorphic coefficients). These families are parametrized by G-invariant functions of pairs (T,s), where T is a hypertorus in X (of codimension 1), and s in G is a reflection acting trivially on T. If G is a real reflection group, these families reduce to the known generalizations of elliptic Calogero-Moser systems, but in the non-real case they appear to be new. We give two constructions of the integrals of these systems - an explicit construction as limits of classical Calogero-Moser Hamiltonians of elliptic Dunkl operators as the dynamical parameter goes to 0 (implementing an idea of arXiv:hep-th/9403178), and a geometric construction as global sections of sheaves of elliptic Cherednik algebras for the critical value of the twisting parameter. We also prove algebraic integrability ...

  3. Surface energy-mediated construction of anisotropic semiconductor wires with selective crystallographic polarity

    Science.gov (United States)

    Sohn, Jung Inn; Hong, Woong-Ki; Lee, Sunghoon; Lee, Sanghyo; Ku, Jiyeon; Park, Young Jun; Hong, Jinpyo; Hwang, Sungwoo; Park, Kyung Ho; Warner, Jamie H.; Cha, Seungnam; Kim, Jong Min

    2014-07-01

    ZnO is a wide band-gap semiconductor with piezoelectric properties suitable for opto-electronics, sensors, and as an electrode material. Controlling the shape and crystallography of any semiconducting nanomaterial is a key step towards extending their use in applications. Whilst anisotropic ZnO wires have been routinely fabricated, precise control over the specific surface facets and tailoring of polar and non-polar growth directions still requires significant refinement. Manipulating the surface energy of crystal facets is a generic approach for the rational design and growth of one-dimensional (1D) building blocks. Although the surface energy is one basic factor for governing crystal nucleation and growth of anisotropic 1D structures, structural control based on surface energy minimization has not been yet demonstrated. Here, we report an electronic configuration scheme to rationally modulate surface electrostatic energies for crystallographic-selective growth of ZnO wires. The facets and orientations of ZnO wires are transformed between hexagonal and rectangular/diamond cross-sections with polar and non-polar growth directions, exhibiting different optical and piezoelectrical properties. Our novel synthetic route for ZnO wire fabrication provides new opportunities for future opto-electronics, piezoelectronics, and electronics, with new topological properties.

  4. Expression, purification, crystallization and preliminary crystallographic analysis of the proliferation-associated protein Ebp1

    Energy Technology Data Exchange (ETDEWEB)

    Kowalinski, Eva; Bange, Gert; Wild, Klemens; Sinning, Irmgard, E-mail: irmi.sinning@bzh.uni-heidelberg.de [Heidelberg University Biochemistry Center, INF 328, D-69120 Heidelberg (Germany)

    2007-09-01

    Preliminary X-ray analysis of the proliferation-associated protein Ebp1 from Homo sapiens is provided. ErbB-3-binding protein 1 (Ebp1) is a member of the family of proliferation-associated 2G4 proteins (PA2G4s) and plays a role in cellular growth and differentiation. Ligand-induced activation of the transmembrane receptor ErbB3 leads to dissociation of Ebp1 from the receptor in a phosphorylation-dependent manner. The non-associated protein is involved in transcriptional and translational regulation in the cell. Here, the overexpression, purification, crystallization and preliminary crystallographic studies of Ebp1 from Homo sapiens are reported. Initially observed crystals were improved by serial seeding to single crystals suitable for data collection. The optimized crystals belong to the tetragonal space group P4{sub 1}2{sub 1}2 or P4{sub 3}2{sub 1}2 and diffracted to a resolution of 1.6 Å.

  5. Protein structure prediction provides comparable performance to crystallographic structures in docking-based virtual screening.

    Science.gov (United States)

    Du, Hongying; Brender, Jeffrey R; Zhang, Jian; Zhang, Yang

    2015-01-01

    Structure based virtual screening has largely been limited to protein targets for which either an experimental structure is available or a strongly homologous template exists so that a high-resolution model can be constructed. The performance of state of the art protein structure predictions in virtual screening in systems where only weakly homologous templates are available is largely untested. Using the challenging DUD database of structural decoys, we show here that even using templates with only weak sequence homology (identity) structural models can be constructed by I-TASSER which achieve comparable enrichment rates to using the experimental bound crystal structure in the majority of the cases studied. For 65% of the targets, the I-TASSER models, which are constructed essentially in the apo conformations, reached 70% of the virtual screening performance of using the holo-crystal structures. A correlation was observed between the success of I-TASSER in modeling the global fold and local structures in the binding pockets of the proteins versus the relative success in virtual screening. The virtual screening performance can be further improved by the recognition of chemical features of the ligand compounds. These results suggest that the combination of structure-based docking and advanced protein structure modeling methods should be a valuable approach to the large-scale drug screening and discovery studies, especially for the proteins lacking crystallographic structures.

  6. Crystallographic and Computational Analyses of AUUCU Repeating RNA That Causes Spinocerebellar Ataxia Type 10 (SCA10).

    Science.gov (United States)

    Park, HaJeung; González, Àlex L; Yildirim, Ilyas; Tran, Tuan; Lohman, Jeremy R; Fang, Pengfei; Guo, Min; Disney, Matthew D

    2015-06-23

    Spinocerebellar ataxia type 10 (SCA10) is caused by a pentanucleotide repeat expansion of r(AUUCU) within intron 9 of the ATXN10 pre-mRNA. The RNA causes disease by a gain-of-function mechanism in which it inactivates proteins involved in RNA biogenesis. Spectroscopic studies showed that r(AUUCU) repeats form a hairpin structure; however, there were no high-resolution structural models prior to this work. Herein, we report the first crystal structure of model r(AUUCU) repeats refined to 2.8 Å and analysis of the structure via molecular dynamics simulations. The r(AUUCU) tracts adopt an overall A-form geometry in which 3 × 3 nucleotide (5')UCU(3')/(3')UCU(5') internal loops are closed by AU pairs. Helical parameters of the refined structure as well as the corresponding electron density map on the crystallographic model reflect dynamic features of the internal loop. The computational analyses captured dynamic motion of the loop closing pairs, which can form single-stranded conformations with relatively low energies. Overall, the results presented here suggest the possibility for r(AUUCU) repeats to form metastable A-from structures, which can rearrange into single-stranded conformations and attract proteins such as heterogeneous nuclear ribonucleoprotein K (hnRNP K). The information presented here may aid in the rational design of therapeutics targeting this RNA.

  7. Scattering of slow ions by various crystallographic planes of tungsten single crystals

    CERN Document Server

    Ermolov, S N; Kortenraad, R; Must, B; Shtinov, E D; Brongersma, K K

    2002-01-01

    The dependence of low-energy ion scattering signal intensity on single crystal surface orientation is investigated, and it is shown that this dependence is not necessarily in direct proportion to atomic density in the uppermost atomic layer. On the basis of comparison of signals from various crystallographic planes of a high purity W single crystal a conclusion is made that the ions scattered from more deep atomic layers contribute considerably to the signal measured for the surface with an open structure. It is shown that reference specimens with a known surface density are needed for quantitative analysis of surface composition by the method of low-energy ion scattering. The best reference specimens are well-oriented single crystals with close-packed planes at the surface, since in this case the low-energy ion scattering signal is proportional to atomic density of the uppermost atomic layer. It single crystals with open surface structure are used as reference specimens the contribution of deeper atomic laye...

  8. CRYSTALLOGRAPHIC RELATIONS OF CEMENTITE–AUSTENITE–FERRITE IN THE DIFFUSIVE DECOMPOSITION OF AUSTENITE

    Directory of Open Access Journals (Sweden)

    BOLSHAKOV V. I.

    2016-05-01

    Full Text Available Summary. It was made a search for new and more accurate orientation relations between the crystal lattice in the pearlite and bainite austenite decomposition products. Methods. It were used the methods: transmission electron microscopy, the micro-, mathematical matrix and stereographic analysis. The purpose of the research is with theoretical, numerical and experimental methods to set up to a 0.2 degree angular orientation relations between the lattices of ferrite and cementite in the austenite decomposition products in the temperature range 400 ... 700С. Results. It was established a new, refined value for grids in the diffusion decay of γ → α + (α + θ. Practical significance. It was proposed a new oriented dependence and the corresponding double gnomonic projection with poles to planes α and θ phases, which can be used in patterns of crystallographic lattices relations studies at phase transitions, as well as the subsequent modeling of complex physical processes of structure formation in metals and binary systems.

  9. Changes of structure and crystallographic texture of cladding tubes from austenitic steel under thermal creep testing

    Science.gov (United States)

    Perlovich, Yu; Isaenkova, M.; Fesenko, V.; Dobrokhotov, P.; Tselishchev, A.

    2016-04-01

    The process of changes in structure and crystallographic texture of cladding tubes from austenitic steel ChS68 under thermal creep testing were studied. Testing of tubes was conducted at the temperature 700 oC in the air by their stretching in axial direction under the stress 160 MPa until rupture. By data of phase and texture analysis a number of processes, accompanying plastic deformation of tubes during thermal creep tests at elevated temperature, were identified. The main texture components of original tube, as well as texture components of different parts of the tested tube are {110} and {112}. In the rupture zone the component of the texture of tension with axis along the tube axis becomes stronger. This effect is connected with activation of dislocation slip in the deformed area of tested tube near the new-formed neck. At the same time the character of texture changes in the zone of tube rupture indicates to development of the dynamic recrystallization, conditioned by the total influence of all factors, which control the passage in the tube of thermal creep. In addition, it was revealed the activation of martensitic transformations in the zone of maximal deformation of tube as a result of its creep tests.

  10. Reintroducing electrostatics into macromolecular crystallographic refinement: application to neutron crystallography and DNA hydration.

    Science.gov (United States)

    Fenn, Timothy D; Schnieders, Michael J; Mustyakimov, Marat; Wu, Chuanjie; Langan, Paul; Pande, Vijay S; Brunger, Axel T

    2011-04-13

    Most current crystallographic structure refinements augment the diffraction data with a priori information consisting of bond, angle, dihedral, planarity restraints, and atomic repulsion based on the Pauli exclusion principle. Yet, electrostatics and van der Waals attraction are physical forces that provide additional a priori information. Here, we assess the inclusion of electrostatics for the force field used for all-atom (including hydrogen) joint neutron/X-ray refinement. Two DNA and a protein crystal structure were refined against joint neutron/X-ray diffraction data sets using force fields without electrostatics or with electrostatics. Hydrogen-bond orientation/geometry favors the inclusion of electrostatics. Refinement of Z-DNA with electrostatics leads to a hypothesis for the entropic stabilization of Z-DNA that may partly explain the thermodynamics of converting the B form of DNA to its Z form. Thus, inclusion of electrostatics assists joint neutron/X-ray refinements, especially for placing and orienting hydrogen atoms.

  11. Protein crystallography for aspiring crystallographers or how to avoid pitfalls and traps in macromolecular structure determination.

    Science.gov (United States)

    Wlodawer, Alexander; Minor, Wladek; Dauter, Zbigniew; Jaskolski, Mariusz

    2013-11-01

    The number of macromolecular structures deposited in the Protein Data Bank now approaches 100,000, with the vast majority of them determined by crystallographic methods. Thousands of papers describing such structures have been published in the scientific literature, and 20 Nobel Prizes in chemistry or medicine have been awarded for discoveries based on macromolecular crystallography. New hardware and software tools have made crystallography appear to be an almost routine (but still far from being analytical) technique and many structures are now being determined by scientists with very limited experience in the practical aspects of the field. However, this apparent ease is sometimes illusory and proper procedures need to be followed to maintain high standards of structure quality. In addition, many noncrystallographers may have problems with the critical evaluation and interpretation of structural results published in the scientific literature. The present review provides an outline of the technical aspects of crystallography for less experienced practitioners, as well as information that might be useful for users of macromolecular structures, aiming to show them how to interpret (but not overinterpret) the information present in the coordinate files and in their description. A discussion of the extent of information that can be gleaned from the atomic coordinates of structures solved at different resolution is provided, as well as problems and pitfalls encountered in structure determination and interpretation.

  12. A new systematic framework for crystallographic analysis of atom probe data

    Energy Technology Data Exchange (ETDEWEB)

    Araullo-Peters, Vicente J., E-mail: vicente.araullopeters@gmail.com [Australian Centre for Microscopy and Microanalysis, University of Sydney (Australia); School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney (Australia); Breen, Andrew; Ceguerra, Anna V. [Australian Centre for Microscopy and Microanalysis, University of Sydney (Australia); School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney (Australia); Gault, Baptiste [Department of Materials, University of Oxford, Parks Road, Oxford (United Kingdom); Ringer, Simon P.; Cairney, Julie M. [Australian Centre for Microscopy and Microanalysis, University of Sydney (Australia); School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney (Australia)

    2015-07-15

    In this article, after a brief introduction to the principles behind atom probe crystallography, we introduce methods for unambiguously determining the presence of crystal planes within atom probe datasets, as well as their characteristics: location; orientation and interplanar spacing. These methods, which we refer to as plane orientation extraction (POE) and local crystallography mapping (LCM) make use of real-space data and allow for systematic analyses. We present here application of POE and LCM to datasets of pure Al, industrial aluminium alloys and doped-silicon. Data was collected both in DC voltage mode and laser-assisted mode (in the latter of which extracting crystallographic information is known to be more difficult due to distortions). The nature of the atomic planes in both datasets was extracted and analysed. - Highlights: • A new analysis method was designed that determines if reconstructed planes are present in atom probe data. • The location, orientation, and planar spacing of these planes are obtained. • This method was applied to simulated, aluminium alloy and silicon data where the extent of planes was shown to vary considerably. • This method can be used to examine atom probe reconstruction quality.

  13. Microstructures and crystallographic preferred orientation of anorthosites from Oman ophiolite and the dynamics of melt lenses

    Science.gov (United States)

    Morales, Luiz F. G.; Boudier, FrançOise; Nicolas, Adolphe

    2011-04-01

    Microstructures and crystallographic preferred orientation (CPO) of anorthosite samples interlayered in the upper and lower gabbro sections in the Oman ophiolite were analyzed in this paper. In the anorthosites registering the dynamics of the melt lenses, foliation is flat lying and starts to develop a few meters below the root zone of the sheeted dike complex (RZSDC). Microstructures and CPO of these rocks were developed in response to four different mechanisms: (1) density-controlled settling of plagioclase on the lens floor, (2) deposition of anorthosites related to convection currents, (3) melt compaction, and (4) uncompacted melt accumulation. In these anorthosites, the poles to (010) of plagioclase are parallel to the flow plane of convection, whereas the [100] axes and poles to (001) express the convection flow direction and the axis of convection rolls, respectively. The effect of subsidence of melt lens floor is recorded immediately below the RZSDC and is characterized by the rapid (but progressive) development of dipping foliation and lineation, reflecting the increase of deformation downsection. The degree of foliation and CPO development in the anorthosites is directly related to the distance of the center of the melt lenses before the subsidence starts. Despite the uncertain origin of the anorthosites from the lower gabbro section, all the samples lost the magmatic microstructural characteristics and presently are reequilibrated aggregates. However, they still preserve plagioclase CPO, where some of these patterns present similarities with the anorthosites from the upper gabbro section, but no evidence of intracrystalline deformation under high temperatures.

  14. Purification and crystallographic analysis of a FAD-dependent halogenase from Streptomyces sp. JCM9888.

    Science.gov (United States)

    Zhao, Yanqun; Yan, Baohua; Yang, Ting; Jiang, Jian; Wei, Heng; Zhu, Xiaofeng

    2015-08-01

    A new FAD (flavin adenine dinucleotide)-dependent halogenase HalY from Streptomyces sp. JCM9888 was reported to be involved in the regioselective halogenation of adenine. HalY is a variant B FAD-dependent halogenase that is most similar to the halogenase PltA involved in pyoluteorin biosynthesis. This study reports the overexpression and purification of HalY with an N-terminal hexahistidine tag, followed by crystallization experiments and X-ray crystallographic analysis. HalY was purified as a monomer in solution and crystallized to give X-ray diffraction to a resolution of 1.7 Å. The crystal belonged to the monoclinic space group P21, with unit-cell parameters a = 41.4, b = 113.4, c = 47.6 Å, α = γ = 90, β = 107.4°, and contained one monomer of HalY in the asymmetric unit, with a calculated Matthews coefficient of 2.3 Å(3) Da(-1) and a solvent content of 46%. The structure of the halogenase CndH was used as a search model in molecular replacement to obtain the initial model of HalY. Manual model building and structure refinement of HalY are in progress.

  15. Interactive inverse kinematics for human motion estimation

    DEFF Research Database (Denmark)

    Engell-Nørregård, Morten Pol; Hauberg, Søren; Lapuyade, Jerome

    2009-01-01

    We present an application of a fast interactive inverse kinematics method as a dimensionality reduction for monocular human motion estimation. The inverse kinematics solver deals efficiently and robustly with box constraints and does not suffer from shaking artifacts. The presented motion...... estimation system uses a single camera to estimate the motion of a human. The results show that inverse kinematics can significantly speed up the estimation process, while retaining a quality comparable to a full pose motion estimation system. Our novelty lies primarily in use of inverse kinematics...... to significantly speed up the particle filtering. It should be stressed that the observation part of the system has not been our focus, and as such is described only from a sense of completeness. With our approach it is possible to construct a robust and computationally efficient system for human motion estimation....

  16. Inverse Bremsstrahlung in Shocked Astrophysical Plasmas

    CERN Document Server

    Baring, M G; Ellison, D C; Baring, Matthew G.; Jones, Frank C.; Ellison, Donald C.

    1999-01-01

    There has recently been interest in the role of inverse bremsstrahlung, the emission of photons by fast suprathermal ions in collisions with ambient electrons possessing relatively low velocities, in tenuous plasmas in various astrophysical contexts. This follows a long hiatus in the application of suprathermal ion bremsstrahlung to astrophysical models since the early 1970s. The potential importance of inverse bremsstrahlung relative to normal bremsstrahlung, i.e. where ions are at rest, hinges upon the underlying velocity distributions of the interacting species. In this paper, we identify the conditions under which the inverse bremsstrahlung emissivity is significant relative to that for normal bremsstrahlung in shocked astrophysical plasmas. We determine that, since both observational and theoretical evidence favors electron temperatures almost comparable to, and certainly not very deficient relative to proton temperatures in shocked plasmas, these environments generally render inverse bremsstrahlung at b...

  17. The Transmuted Generalized Inverse Weibull Distribution

    Directory of Open Access Journals (Sweden)

    Faton Merovci

    2014-05-01

    Full Text Available A generalization of the generalized inverse Weibull distribution the so-called transmuted generalized inverse Weibull distribution is proposed and studied. We will use the quadratic rank transmutation map (QRTM in order to generate a flexible family of probability distributions taking the generalized inverseWeibull distribution as the base value distribution by introducing a new parameter that would offer more distributional flexibility. Various structural properties including explicit expressions for the moments, quantiles, and moment generating function of the new distribution are derived. We propose the method of maximum likelihood for estimating the model parameters and obtain the observed information matrix. A real data set are used to compare the flexibility of the transmuted version versus the generalized inverse Weibull distribution.

  18. Inverse Doppler Effects in Broadband Acoustic Metamaterials.

    Science.gov (United States)

    Zhai, S L; Zhao, X P; Liu, S; Shen, F L; Li, L L; Luo, C R

    2016-08-31

    The Doppler effect refers to the change in frequency of a wave source as a consequence of the relative motion between the source and an observer. Veselago theoretically predicted that materials with negative refractions can induce inverse Doppler effects. With the development of metamaterials, inverse Doppler effects have been extensively investigated. However, the ideal material parameters prescribed by these metamaterial design approaches are complex and also challenging to obtain experimentally. Here, we demonstrated a method of designing and experimentally characterising arbitrary broadband acoustic metamaterials. These omni-directional, double-negative, acoustic metamaterials are constructed with 'flute-like' acoustic meta-cluster sets with seven double meta-molecules; these metamaterials also overcome the limitations of broadband negative bulk modulus and mass density to provide a region of negative refraction and inverse Doppler effects. It was also shown that inverse Doppler effects can be detected in a flute, which has been popular for thousands of years in Asia and Europe.

  19. Full traveltime inversion in source domain

    KAUST Repository

    Liu, Lu

    2017-06-01

    This paper presents a new method of source-domain full traveltime inversion (FTI). The objective of this study is automatically building near-surface velocity using the early arrivals of seismic data. This method can generate the inverted velocity that can kinetically best match the reconstructed plane-wave source of early arrivals with true source in source domain. It does not require picking first arrivals for tomography, which is one of the most challenging aspects of ray-based tomographic inversion. Besides, this method does not need estimate the source wavelet, which is a necessity for receiver-domain wave-equation velocity inversion. Furthermore, we applied our method on one synthetic dataset; the results show our method could generate a reasonable background velocity even when shingling first arrivals exist and could provide a good initial velocity for the conventional full waveform inversion (FWI).

  20. Self-Inverse Interleavers for Turbo Codes

    CERN Document Server

    Sakzad, Amin; Panario, Daniel; Eshghi, Nasim

    2010-01-01

    In this work we introduce and study a set of new interleavers based on permutation polynomials and functions with known inverses over a finite field $\\mathbb{F}_q$ for using in turbo code structures. We use Monomial, Dickson, M\\"{o}bius and R\\'edei functions in order to get new interleavers. In addition we employ Skolem sequences in order to find new interleavers with known cycle structure. As a byproduct we give an exact formula for the inverse of every R\\'edei function. The cycle structure of R\\'edei functions are also investigated. Finally, self-inverse versions of permutation functions are used to construct interleavers. These interleavers are their own de-interleavers and are useful for turbo coding and turbo decoding. Experiments carried out for self-inverse interleavers constructed using these kind of permutation polynomials and functions show excellent agreement with our theoretical results.

  1. Inverse Doppler Effects in Broadband Acoustic Metamaterials

    Science.gov (United States)

    Zhai, S. L.; Zhao, X. P.; Liu, S.; Shen, F. L.; Li, L. L.; Luo, C. R.

    2016-08-01

    The Doppler effect refers to the change in frequency of a wave source as a consequence of the relative motion between the source and an observer. Veselago theoretically predicted that materials with negative refractions can induce inverse Doppler effects. With the development of metamaterials, inverse Doppler effects have been extensively investigated. However, the ideal material parameters prescribed by these metamaterial design approaches are complex and also challenging to obtain experimentally. Here, we demonstrated a method of designing and experimentally characterising arbitrary broadband acoustic metamaterials. These omni-directional, double-negative, acoustic metamaterials are constructed with ‘flute-like’ acoustic meta-cluster sets with seven double meta-molecules; these metamaterials also overcome the limitations of broadband negative bulk modulus and mass density to provide a region of negative refraction and inverse Doppler effects. It was also shown that inverse Doppler effects can be detected in a flute, which has been popular for thousands of years in Asia and Europe.

  2. Nonlinear Least Squares for Inverse Problems

    CERN Document Server

    Chavent, Guy

    2009-01-01

    Presents an introduction into the least squares resolution of nonlinear inverse problems. This title intends to develop a geometrical theory to analyze nonlinear least square (NLS) problems with respect to their quadratic wellposedness, that is, both wellposedness and optimizability

  3. An Inverse Problem Statistical Methodology Summary

    Science.gov (United States)

    2008-01-12

    R. Vogel, Computational Methods for Inverse Problems, SIAM, Philadelphia, 2002. [36] D. D. Wackerly, W. Mendenhall III, and R. L. Scheaffer , Mathematical Statistics with Applications, Duxbury Thompson Learning, USA, 2002. 56

  4. Inverse Doppler Effects in Broadband Acoustic Metamaterials

    National Research Council Canada - National Science Library

    Zhai, S L; Zhao, X P; Liu, S; Shen, F L; Li, L L; Luo, C R

    2016-01-01

    .... With the development of metamaterials, inverse Doppler effects have been extensively investigated. However, the ideal material parameters prescribed by these metamaterial design approaches are complex and also challenging to obtain experimentally...

  5. Inversion of hysteresis and creep operators

    Science.gov (United States)

    Krejčí, Pavel; Al Janaideh, Mohammad; Deasy, Fergal

    2012-05-01

    The explicit inversion formula for rate dependent Prandtl-Ishlinskii operators is extended to cases without the threshold dilation condition. This solves a problem in hysteresis and creep modeling of magnetostrictive behavior.

  6. Inverse agonism and its therapeutic significance

    Directory of Open Access Journals (Sweden)

    Gurudas Khilnani

    2011-01-01

    Full Text Available A large number of G-protein-coupled receptors (GPCRs show varying degrees of basal or constitutive activity. This constitutive activity is usually minimal in natural receptors but is markedly observed in wild type and mutated (naturally or induced receptors. According to conventional two-state drug receptor interaction model, binding of a ligand may initiate activity (agonist with varying degrees of positive intrinsic activity or prevent the effect of an agonist (antagonist with zero intrinsic activity. Inverse agonists bind with the constitutively active receptors, stabilize them, and thus reduce the activity (negative intrinsic activity. Receptors of many classes (α-and β-adrenergic, histaminergic, GABAergic, serotoninergic, opiate, and angiotensin receptors have shown basal activity in suitable in vitro models. Several drugs that have been conventionally classified as antagonists (β-blockers, antihistaminics have shown inverse agonist effects on corresponding constitutively active receptors. Nearly all H 1 and H 2 antihistaminics (antagonists have been shown to be inverse agonists. Among the β-blockers, carvedilol and bucindolol demonstrate low level of inverse agonism as compared to propranolol and nadolol. Several antipsychotic drugs (D 2 receptors antagonist, antihypertensive (AT 1 receptor antagonists, antiserotoninergic drugs and opioid antagonists have significant inverse agonistic activity that contributes partly or wholly to their therapeutic value. Inverse agonism may also help explain the underlying mechanism of beneficial effects of carvedilol in congestive failure, naloxone-induced withdrawal syndrome in opioid dependence, clozapine in psychosis, and candesartan in cardiac hypertrophy. Understanding inverse agonisms has paved a way for newer drug development. It is now possible to develop agents, which have only desired therapeutic value and are devoid of unwanted adverse effect. Pimavanserin (ACP-103, a highly selective 5-HT

  7. LES INVERSIONS LOCATIVES DANS "LA JALOUSIE"

    OpenAIRE

    Fuchs, Catherine; Le Goffic, Pierre

    2016-01-01

    International audience; Chapter 4 is devoted to a linguistic analysis of the 47 examples of locative inversions which are to be found in Robbe-Grillet's novel La Jalousie. We successively consider the ordering, the internal structure, the lexical characteristics and the determiners of the three main constituents (namely the Location Phrase, the Verbal Phrase and the nominal Subject Phrase). The analysis enlightens the non prototypical way in which the author uses locative inversion structures...

  8. Study of Inverse Creep In Textile Yarns

    Directory of Open Access Journals (Sweden)

    P.G. Patil

    2009-12-01

    Full Text Available Creep has been known and studied for textilematerials for decades. In comparison, a newlyobserved phenomenon of inverse creep seems not tohave received much attention. A new instrument hasbeen fabricated to measure creep and inverse creep intextile materials particularly yarns. Creep and Inversecreep measurements of nylon multifilament yarn,polyester multifilament yarn, cotton and wool yarn atdifferent levels of stress have been studied using thenew instrument and results are reported in the presentpaper.

  9. Inverse semigroups the theory of partial symmetries

    CERN Document Server

    Lawson, Mark V

    1998-01-01

    Symmetry is one of the most important organising principles in the natural sciences. The mathematical theory of symmetry has long been associated with group theory, but it is a basic premise of this book that there are aspects of symmetry which are more faithfully represented by a generalization of groups called inverse semigroups. The theory of inverse semigroups is described from its origins in the foundations of differential geometry through to its most recent applications in combinatorial group theory, and the theory tilings.

  10. Inverse Distance Weighted Interpolation Involving Position Shading

    OpenAIRE

    Li, Zhengquan; WU Yaoxiang

    2015-01-01

    Considering the shortcomings of inverse distance weighted (IDW) interpolation in practical applications, this study improved the IDW algorithm and put forward a new spatial interpolation method that named as adjusted inverse distance weighted (AIDW). In interpolating process, the AIDW is capable of taking into account the comprehensive influence of distance and position of sample point to interpolation point, by adding a coefficient (K) into the normal IDW formula. The coefficient (K) is used...

  11. Inverse problems in stochastic computational dynamics

    OpenAIRE

    Capiez-Lernout, Evangéline; Soize, Christian

    2008-01-01

    International audience; This paper deals with robust updating of dynamical systems using stochastic computational models for which model and parameter uncertainties are taken into account by the nonparametric probabilistic approach. Such a problem is formulated as an inverse problem consisting in identifying the parameters of the mean computational model and the parameters of the probabilistic model of uncertainties. This inverse problem leads us to solve an optimization problem for which the...

  12. Bayesian Inversion of Seabed Scattering Data

    Science.gov (United States)

    2014-09-30

    uncertainties as well as parameter values, thereby quantifying the information content of the data to resolve the model parameters. Bayesian inversion...method based on deviance information criterion to determine the dominant scattering mechanism is in development. This work has been compiled in two... Bayesian Inversion of Seabed Scattering Data (Special Research Award in Ocean Acoustics) Gavin A.M.W. Steininger School of Earth & Ocean

  13. INVERSE COEFFICIENT PROBLEMS FOR PARABOLIC HEMIVARIATIONAL INEQUALITIES

    Institute of Scientific and Technical Information of China (English)

    Liu Zhenhai; I.Szántó

    2011-01-01

    This paper is devoted to the class of inverse problems for a nonlinear parabolic hemivariational inequality.The unknown coefficient of the operator depends on the gradient of the solution and belongs to a set of admissible coefficients.It is proved that the convergence of solutions for the corresponding direct problems continuously depends on the coefficient convergence.Based on this result the existence of a quasisolution of the inverse problem is obtained.

  14. An inverse problem in analytical dynamics

    Institute of Scientific and Technical Information of China (English)

    Li Guang-Cheng; Mei-Feng-Xiang

    2006-01-01

    This paper presents an inverse problem in analytical dynamics.The inverse problem is to construct the Lagrangian when the integrals of a system are given.Firstly,the differential equations are obtained by using the time derivative of the integrals.Secondly,the differential equations can be written in the Lagrange equations under certain conditions and the Lagrangian can be obtained.Finally,two examples are given to illustrate the application of the result.

  15. Crystallographic analysis of TPP riboswitch binding by small-molecule ligands discovered through fragment-based drug discovery approaches.

    Science.gov (United States)

    Warner, Katherine Deigan; Ferré-D'Amaré, Adrian R

    2014-01-01

    Riboswitches are structured mRNA elements that regulate gene expression in response to metabolite or second-messenger binding and are promising targets for drug discovery. Fragment-based drug discovery methods have identified weakly binding small molecule "fragments" that bind a thiamine pyrophosphate (TPP) riboswitch. However, these fragments require substantial chemical elaboration into more potent, drug-like molecules. Structure determination of the fragments bound to the riboswitch is the necessary next step. In this chapter, we describe the methods for co-crystallization and structure determination of fragment-bound TPP riboswitch structures. We focus on considerations for screening crystallization conditions across multiple crystal forms and provide guidance for building the fragment into the refined crystallographic model. These methods are broadly applicable for crystallographic analyses of any small molecules that bind structured RNAs.

  16. Glassy Carbon Electrode-Supported Au Nanoparticles for the Glucose Electrooxidation: On the Role of Crystallographic Orientation

    Directory of Open Access Journals (Sweden)

    M. Guerra-Balcázar

    2012-01-01

    Full Text Available Glucose electrooxidation in alkaline solution was examined using glassy carbon electrodes modified with Au nanoparticles. Au nanoparticles were prepared following the two-phase protocol and characterized by transmission electron microscopy (TEM, UV-Vis spectroscopy, X-ray diffraction spectroscopy (XRD, and cyclic voltammetry (CV. It was found that, under the study conditions, it is possible to obtain nanoparticles between 1 and 5 nm; also it was found that the crystallographic orientation is strongly influenced by the ratio metal/thiol and to a lesser extent by the synthesis temperature. The voltammetric response for the electrocatalytic oxidation of glucose at carbon Au nanoparticle-modified electrode shows an increasing activity with nanoparticles size. Electroactivity and possibly selectivity are found to be nanoparticles' crystallographic orientation dependent. Classical electrochemical analysis shows that glucose electrooxidation is a diffusion-controlled process followed by a homogenous reaction.

  17. Inversion of receiver function by wavelet transformation

    Institute of Scientific and Technical Information of China (English)

    吴庆举; 田小波; 张乃铃; 李桂银; 曾融生

    2003-01-01

    A new method for receiver function inversion by wavelet transformation is presented in this paper. Receiver func-tion is expanded to different scales with different resolution by wavelet transformation. After an initial model be-ing taken, a generalized least-squares inversion procedure is gradually carried out for receiver function from low tohigh scale, with the inversion result for low order receiver function as the initial model for high order. Aneighborhood containing the global minimum is firstly searched from low scale receiver function, and will gradu-ally focus at the global minimum by introducing high scale information of receiver function. With the gradual ad-dition of high wave-number to smooth background velocity structure, wavelet transformation can keep the inver-sion result converge to the global minimum, reduce to certain extent the dependence of inversion result on theinitial model, overcome the nonuniqueness of generalized least-squares inversion, and obtain reliable crustal andupper mantle velocity with high resolution.

  18. Geoacoustic inversion with ships as sources.

    Science.gov (United States)

    Koch, Robert A; Knobles, David P

    2005-02-01

    Estimation of geoacoustic parameters using acoustic data from a surface ship was performed for a shallow water region in the Gulf of Mexico. The data were recorded from hydrophones in a bottom mounted, horizontal line array (HLA). The techniques developed to produce the geoacoustic inversion are described, and an efficient method for geoacoustic inversion with broadband beam cross-spectral data is demonstrated. The performance of cost functions that involve coherent or incoherent sums over frequency and one or multiple time segments is discussed. Successful inversions for the first sediment layer sound speed and thickness and some of the parameters for the deeper layers were obtained with the surface ship at nominal ranges of 20, 30, or 50 water depths. The data for these inversions were beam cross-spectra from four subapertures of the HLA spanning a little more than two water depths. The subaperture beams included ten frequencies equally spaced in the 120-200 Hz band. The values of the geoacoustic parameters from the inversions are validated by comparisons with geophysical observations and with the parameter values from previous inversions by other invesigators, and by comparing transmission loss (TL) measured in the experiment with modeled TL based on the inverted geoacoustic parameters.

  19. Image Fusion for Travel Time Tomography Inversion

    Directory of Open Access Journals (Sweden)

    Liu Linan

    2015-09-01

    Full Text Available The travel time tomography technology had achieved wide application, the hinge of tomography was inversion algorithm, the ray path tracing technology had a great impact on the inversion results. In order to improve the SNR of inversion image, comprehensive utilization of inversion results with different ray tracing can be used. We presented an imaging fusion method based on improved Wilkinson iteration method. Firstly, the shortest path method and the linear travel time interpolation were used for forward calculation; then combined the improved Wilkinson iteration method with super relaxation precondition method to reduce the condition number of matrix and accelerate iterative speed, the precise integration method was used to solve the inverse matrix more precisely in tomography inversion process; finally, use wavelet transform for image fusion, obtain the final image. Therefore, the ill-conditioned linear equations were changed into iterative normal system through two times of treatment and using images with different forward algorithms for image fusion, it reduced the influence effect of measurement error on imaging. Simulation results showed that, this method can eliminate the artifacts in images effectively, it had extensive practical significance.

  20. An application of sparse inversion on the calculation of the inverse data space of geophysical data

    KAUST Repository

    Saragiotis, Christos

    2011-07-01

    Multiple reflections as observed in seismic reflection measurements often hide arrivals from the deeper target reflectors and need to be removed. The inverse data space provides a natural separation of primaries and surface-related multiples, as the surface multiples map onto the area around the origin while the primaries map elsewhere. However, the calculation of the inverse data is far from trivial as theory requires infinite time and offset recording. Furthermore regularization issues arise during inversion. We perform the inversion by minimizing the least-squares norm of the misfit function and by constraining the 1 norm of the solution, being the inverse data space. In this way a sparse inversion approach is obtained. We show results on field data with an application to surface multiple removal. © 2011 IEEE.